Note: Descriptions are shown in the official language in which they were submitted.
PORTABLE DEFECT MITIGATOR
FOR ELECTROCHROMIC WINDOWS
[00011
FIELD
[0002] The present disclosure concerns apparatus, systems, and methods for
mitigating
defects in electronic devices on substrates, e.g., where such defects can be
visually perceived
by the end user, such as flat panel displays, photovoltaic windows,
electrochromic devices,
and the like, particularly electrochromic windows.
BACKGROUND
[0003] Electrochromism is a phenomenon in which a material exhibits a
reversible
electrochemically-mediated change in an optical property when placed in a
different
electronic state, typically by being subjected to a voltage change. The
optical property is
typically one or more of color, transmittance, absorbance, and reflectance.
While
electrochromism was discovered in the 1960s, electrochromic devices still
unfortunately
suffer various problems and have not begun to realize their full commercial
potential.
[00041 Electrochromic materials may be incorporated into, for example,
windows and
mirrors. The color, transmittance, absorbance, and/or reflectance of such
windows and
mirrors may be changed by inducing a change in the electrochromic material.
However,
advancements in electrochromic technology, apparatus, and related methods of
making
and/or using them, are needed because conventional electrochromic windows
suffer from, for
example, high defectivity and low versatility.
[0005] Electrochromic windows are made by forming an electrochromic device
on a pane
of transparent material. During production, the electrochromic device on the
pane is
scrutinized for any defects that would cause visual distortions or anomalies
to the end user of
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the window. These defects are then mitigated. Mitigation may include isolating
short type
defects using probes and then "zapping" the short defect by applying a
localized electric arc
to overload and destroy the short conduction path. Other methods of mitigation
include, for
example, identifying visual defects and then circumscribing each defect with a
laser to
electronically isolate the defect and thereby lower or eliminate the visual
effect the defect
would create when the window is in a colored state. Similar mitigation efforts
are made for
other electronic devices on substrates where such defects can be visually
perceived by the end
user, such as flat panel displays. The electronic device may be analyzed for
defects on one
machine and then the defects mitigated on another machine in a production
facility setting.
Such defect detection and mitigation apparatus for flat panel displays are
commercially
available, for example, under the trade names of ArrayCheckerTM and
ArraySaverTM which
are made by Orbotech Inc. of Billerica, Massachusetts.
SUMMARY
[0006] Systems, methods, an apparatus for identifying and mitigating
defects in
electronic devices on substrates, which may be included in flat panel
displays, photovoltaic
windows, electrochromic windows, and the like. In some cases, the apparatus
may be a
portable defect mitigator that can be easily transported to identify and
mitigate a defect in the
electronic device located in the field (e.g., an electrochromic window
installed in a building).
The portable defect mitigator may be a hand-held operated design that can be
easily
maneuvered and affixed to the surface of the window during the procedure.
[0007] In the field, a window may be subjected to forces (e.g., wind gusts)
that can bend
or otherwise deform the window. Certain embodiments include a dynamic
autofocus system
for automatically focusing a laser during mitigation of a defect in an
electronic device of a
deforming window. The dynamic autofocus system has a focal lens for focusing
the
collimated light from a laser mitigating the defect. The dynamic autofocus
system also has a
detector mechanism (e.g., triangulation sensor) for measuring a separation
distance to the
surface of the electronic device. The detector mechanism takes this
measurement at one or
more sample times. The dynamic autofocus system also has a lens positioning
mechanism
for moving the lens to about a focal length from the surface of the electronic
device based on
the separation distance measured at the sample time. The dynamic autofocus
system also has
a processor that can send a signal to the lens positioning mechanism to move
the focal lens.
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In one case, the detector mechanism also measures a rate of change of the
separation distance
at the sample time. The processor predicts the separation distance at a future
time based on
the separation distance and its rate of change measured at the sample time.
The lens
positioning mechanism moves the lens to about the focal length based on the
predicted
separation distance at the future time determined from the measured separation
distance and
rate of change at the sample time.
[0008] In one aspect, the portable defect mitigator may include a vacuum
engagement
system for affixing the mitigator to a window surface. The vacuum engagement
system
includes a plurality of isolated recesses and a groove around each of the
recesses. The system
also includes 0-rings, each 0-ring is configured to fit within one of the
grooves. Each of the
recesses is vacuum sealed with the 0-ring to form a vacuum chamber with the
window
surface. The vacuum engagement system may a set of valves. Each valve is
configured to
control vacuum in one of the vacuum chambers. The valves may be independently
controlled.
[0009] In some embodiments, a portable defect mitigator includes a first
mechanism
configured to detect the defect, a second mechanism configured to mitigate the
defect, and a
dichroic mirror for receiving collimated illumination from the first mechanism
and the second
mechanism. The portable defect mitigator also includes a reflective mirror for
receiving
collimated illumination along a coaxial path from the dichroic mirror and a
focal lens
receiving collimated illumination reflected from the mirror and focusing the
illumination to
the electronic device to image and mitigate the defect. In some cases, the
portable defect
mitigator may include a pivoting mechanism for pivoting the mirror and focal
lens about a
pivot point to focus the illumination at an angle to a plane at a surface of
the electronic
device. For example, the focal lens can focus the illumination to a focal
point at a corner of
an insulated glass unit. As another example, the focal lens can focus the
illumination to a
focal point under a spacer of an insulated glass unit.
[0010] One embodiment is a method of mitigating a defect in an electronic
device on a
window using a portable defect mitigator. The method includes mounting the
portable defect
mitigator to a surface of the window. The method also includes focusing a
laser on the
surface of the electronic device and identifying one or more defects in a
field of view. The
method also includes mitigating a selected defect using a laser based on a
selected scribe
pattern.
3
[0011] In embodiments, the portable defect mitigator may include one or
more
subsystems with a variety of functionalities. One subsystem is an X-Y stage
for increasing the
field of view of the mitigating laser and the imaging device. Another
subsystem is a Z-stage
for moving the focal point of the laser and/or imaging device. Another
subsystem is a tether
system for tethering the portable defect mitigator for added safety. Another
subsystem is a
vacuum engagement system for affixing the portable defect mitigator to the
surface of the
window. Another subsystem is a dynamic autofocus system. Another subsystem
includes
imaging and mitigation systems which share a common axis from a dichroic
mirror through
the focal lens and onto the window surface. Another subsystem is a pivot
system for pivoting
the optics in a portable defect mitigator mounted to the window in order to
image and mitigate
defects at the corners or underneath a spacer of an IGU. Another subsystem is
a light tight
hand-held chassis and/or a case-like structure separate from the chassis.
Another subsystem is
a tracking stylus for manually inputting defect locations. Another subsystem
is a beam
blocker.
According to an aspect of the present invention, there is provided a dynamic
autofocus system for automatically focusing a laser during mitigation of a
defect in an
electronic device of a deforming window, the system comprising:
a focal lens configured to focus collimated light from a laser mitigating the
defect;
a detector mechanism configured to measure a separation distance to a surface
of
the electronic device at a sample time;
a lens positioning mechanism configured to move the focal lens to about a
focal
length from the surface of the electronic device based on the separation
distance measured at
the sample time; and
a processor adapted to send a signal to the lens positioning mechanism to
cause
the focal lens to move;
wherein the processor is further adapted to determine a rate of change of the
separation distance at the sample time based on the measured separation
distance, and adapted
to predict a future separation distance at a future time based on the measured
separation
distance and determined rate of change; and
wherein the lens positioning mechanism is configured to move the focal lens to
about the focal length from the surface of the electronic device according to
the predicted
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separation distance from the surface of the electronic device determined based
on the
measured separation distance.
According to another aspect of the present invention, there is provided a
vacuum
engagement system for affixing a portable defect mitigator to a window
surface, the system
comprising:
a plurality of isolated recesses in a surface of the portable defect
mitigator;
a groove around each isolated recess; and
an 0-ring configured to fit within the groove;
wherein each recess forms an isolated vacuum chamber with the window surface
when sealed with the 0-ring located in the groove.
According to another aspect of the present invention, there is provided a
portable
defect mitigator for mitigating a defect in an electronic device of a window,
the portable defect
mitigator comprising:
a first mechanism configured to detect the defect;
a second mechanism configured to mitigate the defect;
a dichroic mirror configured to receive collimated illumination from the first
mechanism and collimated illumination from the second mechanism;
a reflective mirror configured to receive collimated illumination from the
first and
second mechanisms along a coaxial path from the dichroic mirror; and
a focal lens configured to receive collimated illumination reflected from the
reflective mirror and configured to focus the collimated illumination to the
electronic device to
image and mitigate the defect.
According to another aspect of the present invention, there is provided a
method
of mitigating a defect in an electronic device on a window using a portable
defect mitigator,
the method including:
mounting the portable defect mitigator to a surface of the window;
focusing a laser on the surface of the electronic device;
identifying one or more defects in a field of view;
mitigating a selected defect using a laser based on a selected scribe pattern;
and
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wherein mounting the portable defect mitigator to the surface of the window
comprises applying a vacuum to chambers formed between a plurality of recesses
in a surface
of the portable defect mitigator and the mating surface of the window.
According to another aspect of the present invention, there is provided a
dynamic
autofocus system for automatically focusing a laser during mitigation of a
defect in an
electronic device disposed on a window that is deforming during defect
mitigation, the
dynamic autofocus system comprising:
a focal lens configured to focus collimated light from the laser mitigating
the defect;
a detector mechanism configured to take measurements over time of separation
distance to a surface of the electronic device disposed on the deforming
window; and
a processor configured to:
determine a rate of change of separation distance using the measurements
taken over time by the detector mechanism;
predict a first distance occurring at a future time using the determined rate
of change, and
send a signal to a lens positioning mechanism to move the focal lens; and
the lens positioning mechanism configured to move the focal lens to about a
focal
length from the surface of the electronic device using to the first distance
predicted to occur at
the future time.
[0012] These and other features and embodiments will be described in
more detail below
with reference to the drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0013] Figures 1A and 1B depict the structure and function of
electrochromic devices.
[0014] Figure 2 depicts a particle defect in an electrochromic device.
[0015] Figures 3A-3C depict aspects of formation of a pop-off defect.
[0016] Figure 4 depicts aspects of a dark field illumination technique.
4b
Date Recue/Date Received 2020-10-09
[0017] Figure 5A depicts a perspective of an apparatus for identifying
and remediating a
visual defect.
[0018] Figure 5B depicts a rail or track system for apparatus as
described herein.
[0019] Figure 5C depicts a coaxial optical path for laser and detection
optics.
[0020] Figure 5D depicts a pre-firing alignment process.
4c
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[0021] Figures 6 and 7 depict various aspects of apparatus for identifying
and
remediating a visual defect.
[0022] Figures 8A-8C depict aspects of a process flow.
[0023] Figure 9 is a schematic diagram of a dynamic autofocus system in a
portable
defect mitigator, according to embodiments.
[0024] Figure 10 is a schematic diagram of a triangulation sensor of a
dynamic autofocus
system, according to embodiments.
[0025] Figure 11A is a schematic diagram of an optical system in a compact
arrangement
having a mirror at a nominal position, according to embodiments.
[0026] Figure 11B is a schematic diagram of the optical system of Figure
11A with the
mirror tilted upward.
[0027] Figure 12 is a schematic diagram of an optical system in a compact
arrangement,
according to embodiments.
[0028] Figures 13A-H are isometric line drawings of a portable defect
mitigator,
according to embodiments.
[0029] Figure 14 is a flowchart of a method of using a portable defect
mitigator,
according to embodiments.
DETAILED DESCRIPTION
[0030] ELECTROCHROMIC DEVICES
[0031] Figures 1A and 1B are schematic cross-sections of an electrochromic
device, 100,
showing a common structural motif for such devices, and further, the function
of such
devices is summarized below. Electrochromic device 100 includes a substrate
102, a
conductive layer (CL) 104, an electrochromic layer (EC) 106, an ion conducting
(electrically
resistive) layer (IC) 108, a counter electrode layer (CE) 110, and another
conductive layer
(CL) 112. Elements 104, 106, 108, 110, and 112 are collectively referred to as
an
electrochromic stack, 114. A voltage source, 116, operable to apply an
electric potential
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across electrochromic stack 112 effects the transition of the electrochromic
device from, e.g.,
a bleached state (refer to Figure 1A) to a colored state (refer to Figure 1B).
The order of
layers may be reversed with respect to the substrate. That is, the layers may
be in the
following order: substrate, conductive layer, counter electrode layer, ion
conducting layer,
electrochromic material layer, and conductive layer. The conductive layers
commonly
comprise transparent conductive materials, such as metal oxides, alloy oxides,
and doped
versions thereof, and are commonly referred to as "TCO" layers because they
are made from
transparent conducting oxides. Device 100 is meant for illustrative purposes,
in order to
understand the context of embodiments described herein. Methods and apparatus
described
herein are used to identify and mitigate defects in electrochromic devices,
regardless of the
structural motif of the electrochromic device, so long as there is a stacked
device structure
that functions similarly to device 100, that is, devices that can have visual
defects that can be
mitigated as described herein.
[0032] During normal operation, electrochromic devices such as 100
reversibly cycle
between a bleached state and a colored state. As depicted in Figure 1A, in the
bleached state,
a potential is applied across the electrodes (transparent conductor layers 104
and 112) of
electrochromic stack 114 such that available ions (e.g. lithium ions) in the
stack that would
otherwise cause electrochromic material 106 to be in the colored state reside
primarily in the
counter electrode 110, and thus electrochromic layer 106 is in a bleached
state. In certain
electrochromic devices, when loaded with the available ions, counter electrode
layer 110 is
also in a bleached state (thus it can be thought of as an ion storage area of
the device).
[0033] Referring to Figure 1B, when the potential on the electrochromic
stack is
reversed, the ions are transported across ion conducting layer 108 to
electrochromic layer 106
and cause the material to enter the colored state. In certain electrochromic
devices, the
depletion of ions from the counter electrode material causes it to color also
(as depicted, thus
in this example counter electrode layer 110 is a lithium storage area when the
device is
bleached, and also functions to color the device when the ions leave layer
110). Thus, there
is a synergistic effect where the transition to colored states for both layers
106 and 110 are
additive toward reducing the amount of light transmitted through the stack.
When the voltage
is no longer applied to device 100, ions travel from electrochromic layer 106,
through the ion
conducting layer 108, and back into counter electrode layer 110.
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[0034] Electrochromic devices such as described in relation to Figures lA
and 1B are
used to fabricate, for example, electrochromic windows. For example, substrate
102 may be
architectural glass upon which electrochromic devices are fabricated.
Architectural glass is
glass that is used as a building material. Architectural glass is typically
used in commercial
buildings, but may also be used in residential buildings, and typically,
though not necessarily,
separates an indoor environment from an outdoor environment. In certain
embodiments,
architectural glass is at least 20 inches by 20 inches, and can be much
larger, e.g., as large as
about 72 inches by 120 inches.
[0035] As larger and larger substrates are used for electrochromic windows
it is desirable
to minimize defects in the electrochromic device, because otherwise the
performance and
visual quality of the electrochromic windows will suffer. Even if defects are
minimized,
there will be some defects in the final product that must be mitigated.
Understanding the
needs addressed by embodiments described herein requires a better
understanding of
defectivity in electrochromic windows.
[0036] DEFECTIUTY IN ELECTROCHROMIC WINDOWS
[0037] As used herein, the term "defect" refers to a defective point or
region of an
electrochromic device. Defects may be caused by electrical shorts or by
pinholes. Further,
defects may be characterized as visible or non-visible. In general, a defect
in an
electrochromic device, and sometimes an area around the defect, does not
change optical
state (e.g., color) in response to an applied potential that is sufficient to
cause non-defective
regions of the electrochromic device to color or otherwise change optical
state. Often a
defect will be manifest as visually discernible anomalies in the
electrochromic window or
other device. Such defects are referred to herein as "visible" defects. Other
defects are so
small that they are not visually noticeable to the observer in normal use
(e.g., such defects do
not produce a noticeable light point or "pinhole" when the device is in the
colored state
during daytime).
[0038] A short is a localized electronically conductive pathway spanning
the ion
conducting layer (e.g., an electronically conductive pathway between the two
TCO layers).
Typically, a defect causing a visible short will have a physical dimension of
about 3
micrometers, sometimes less, which is a relatively small defect from a visual
perspective. However, these relatively small defects result in a visual
anomaly, the halo, in
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the colored electrochromic window that are, for example, about 1 centimeter in
diameter,
sometimes larger. Halos can be reduced significantly by isolating the defect,
for example by
circumscribing the defect via a laser scribe or by ablating the material
directly without
circumscribing it. For example, a circular, oval, triangular, rectangular, or
other shaped
perimeter is ablated around the shorting defect thus electrically isolating it
from the rest of
the functioning device. The circumscription may be only tens, a hundred, or up
to a few
hundred micrometers in diameter. By circumscribing, and thus electrically
isolating the
defect, the visible short will resemble only a small point of light to the
naked eye when the
window is colored and there is sufficient light on the other side of the
window. When ablated
directly, without circumscription, there remains no EC device material in the
area where the
electrical short defect once resided. Rather, there is a hole through the
device and at the base
of the hole is, for example, the float glass or the diffusion barrier or the
lower transparent
electrode material, or a mixture thereof. Since these materials are all
transparent, light may
pass through the base of the hole in the device. Depending on the diameter of
a
circumscribed defect, and the width of the laser beam, circumscribed pinholes
may also have
little or no electrochromic material remaining within the circumscription (as
the
circumscription is typically, though not necessarily, made as small as
possible). Such
mitigated short defects manifest as pin points of light against the colored
device, thus these
points of light are commonly referred to as -pinholes." Isolation of an
electrical short by
circumscribing or direct ablation would be an example of a man-made pinhole,
one purposely
formed to convert a halo into a much smaller visual defect. However, pinholes
may also arise
as a natural result of defects in the optical device.
[0039] A pinhole
is a region where one or more layers of the electrochromic device are
missing or damaged so that electrochromism is not exhibited. Pinholes are not
electrical
shorts, and, as described above, they may be the result of mitigating an
electrical short in the
device. A pinhole may have a defect dimension of between about 25 micrometers
and about
300 micrometers, typically between about 50 micrometers and about 150
micrometers, thus it
is much harder to discern visually than a halo. Typically, in order to reduce
the visible
perception of pinholes resulting from mitigation of halos, one will limit the
size of a
purposely-created pinhole to about 100 micrometers or less.
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Particle
Worst Case Failure Effect
Location
on substrate pops off leaving pinhole pinhole
pops off allowing ITO- visible short
on TEC
TEC short voltage drop
visible short
on EC leakage across IC
voltage drop
on IC pops off leaving pinhole pinhole
on CE pops off leaving pinhole pinhole
[0040] In some cases, an electrical short is created by a conductive
particle lodging in
and/or across the ion conducting layer, thereby causing an electronic path
between the
counter electrode layer and the electrochromic layer or the TCO associated
with either one of
them. A defect may also be caused by a particle on the substrate on which the
electrochromic
stack is fabricated. When such a particle causes layer delamination due to
stresses imparted
by the particle, this is sometimes called "pop-off. " In other instances, the
layers do not
adhere to the substrate properly and delaminate, interrupting the flow of ions
and/or electrical
current within the device. These types of defects are described in more detail
below in
relation to Figures 2 and 3A - 3C. A delamination or pop-off defect can lead
to a short if it
occurs before a TCO or associated EC or CE is deposited. In such cases, the
subsequently
deposited TCO or EC/CE layer will directly contact an underlying TCO or CE/EC
layer
providing direct electronic conductive pathway. A few examples of defect
sources are
presented in the table below. The table below is intended to provide examples
of mechanisms
that lead to the different types of visible and non-visible defects.
Additional factors exist
which may influence how the EC window responds to a defect within the stack.
[0041] As noted above, in the case of a visible short the defect will
appear as a light
central region (when the device is in the colored state) with a diffuse
boundary such that the
device gradually darkens with distance from the center of the short. If there
are a significant
number of electrical shorts (visible or non-visible) concentrated in an area
of an
electrochromic device, they may collectively impact a broad region of the
device whereby the
device cannot switch in such region. This is because the potential difference
between the EC
and CE layers in such regions cannot attain a threshold level required to
drive ions across the
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ion conductive layer. It should be understood that leakage current may result
from sources
other than short-type defects. Such other sources include broad-based leakage
across the ion
conducting layer and edge defects such as roll off defects as described
elsewhere herein and
scribe line defects. The emphasis here is on leakage caused only by points of
electrical
shorting across the ion conducting layer in the interior regions of the
electrochromic device.
These shorts cause visible defects that must be minimized and/or mitigated for
the
electrochromic pane to be acceptable for use in an electrochromic window.
Conventionally,
the visual defects are identified and mitigated prior to assembly of the pane
into an insulated
glass unit (IGU). Methods described herein allow identification and mitigation
after the pane
is fabricated into an IGU and also after installed in a building or, for
example, after the pane
is installed in an automobile.
[0042] Since an IGU may include inure than two glass panes assembled into a
unit (e.g. a
triple pane unit), and for electrochromic windows specifically may include
electrical leads for
connecting the electrochromic glass to a voltage source, switches and the
like, the term
"window unit" is used to convey a more simple sub-assembly. That is, for the
purposes of
this invention, an IGU may include more components than a window unit. The
most basic
assembly of a window unit is two substrates (panes or glazings) with a sealing
separator in
between and registered with the two substrates.
[0043] Figure 2 is a schematic cross-section of an electrochromic device,
200, with a
particle, 205, in the ion conducting layer causing a localized defect in the
device. In this
example, electrochromic device 200 includes the same layers as described in
relation to
Figures lA and 1B. Voltage source 116 is configured to apply a potential to
electrochromic
stack 114 as described above, through suitable connections (e.g., bus bars) to
conductive
layers 104 and 112.
[0044] In this example, ion conducting layer 108 includes a conductive
particle, 205, or
other artifact causing a defect. Conductive particle 205 results in a short
between
electrochromic layer 106 and counter electrode layer 110. In this example,
particle 205 spans
the thickness of the IC layer 108. Particle 205 physically impedes the flow of
ions between
electrochromic layer 106 and counter electrode layer 110, and also, due to its
electrical
conductivity, allows electrons to pass locally between the layers, resulting
in a transparent
region 210 in electrochromic layer 106 and a transparent region 220 in counter
electrode
layer 110. Transparent region 210 exists when the remainder of layers 110 and
106 are in the
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colored state. That is, if electrochromic device 200 is in the colored state,
conductive particle
205 renders regions 210 and 220 of the electrochromic device unable to enter
into the colored
state. Sometimes such visible defect regions are referred to as
"constellations" or "halos"
because they appear as a series of bright spots (or stars) against a dark
background (the
remainder of the device being in the colored state). Humans will naturally
direct their
attention to the halos and often find them distracting or unattractive.
Embodiments described
herein identify and mitigate such visible defects. Pinhole defects may or may
not be deemed
worthy of repair, as they can be nearly indiscernible to the naked eye by most
observers.
[0045] It should be noted that defect mitigators described herein may have
optical
detection components that allow detection of defects not discernible to the
human eye.
Moreover, the mitigation components described herein can repair such defects.
Embodiments described herein are thus not limited to portable defect
mitigators that detect
and repair defects visually discernible to the human eye; however, visually
discernible
defects are of most concern from an end user perspective. Non-visually
discernible defects
can lead to poor device performance in the aggregate due to their associated
leakage current,
and thus may also be mitigated using apparatus and methods as described
herein.
[0046] As mentioned above, visible short defects can also be caused by
particles popping
off, e.g. during or after fabrication of the electrochromic device, thereby
creating damaged
areas in the electrochromic stack, through one or more layers of the stack.
Pop-off defects
are described in more detail below.
[0047] Figure 3A is a schematic cross-section of an electrochromic device,
300, with a
particle 305 or other debris on conductive layer 104 prior to depositing the
remainder of the
electrochromic stack. Electrochromic device 300 includes the same components
as
electrochromic device 100. Particle 305 causes the layers in the
electrochromic stack 114 to
bulge in the region of particle 305, due to conformal layers 106-110 being
deposited
sequentially over particle 305 as depicted (in this example, conductive layer
112 has not yet
been deposited). While not wishing to be bound by a particular theory, it is
believed that
layering over such particles, given the relatively thin nature of the layers,
can cause stress in
the area where the bulges are formed. More particularly, in each layer, around
the perimeter
of the bulged region, there can be defects in the layer, e.g. in the lattice
arrangement or on a
more macroscopic level, cracks or voids. One consequence of these defects
would be, for
example, an electrical short between electrochromic layer 106 and counter
electrode layer
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110 and/or loss of ion conductivity in layer 108. These defects are not
depicted in Figure
3A, however.
[0048] Referring to Figure 3B, another consequence of defects caused by
particle 305 is
called a "pop-off" In this example, prior to deposition of conductive layer
112, a portion
above the conductive layer 104 in the region of particle 305 breaks loose,
carrying with it
portions of electrochromic layer 106, ion conducting layer 108, and counter
electrode layer
110. The "pop-off' is piece 310, which includes particle 305, a portion of
electrochromic
layer 106, as well as ion conducting layer 108 and counter electrode layer
110. The result is
an exposed area of conductive layer 104 at the bottom of the trench left when
piece 310
popped out of the layered stack of materials. Referring to Figure 3C, after
pop-off and once
conductive layer 112 is deposited, an electrical short is formed where
conductive layer 112
comes in contact with conductive layer 104. This electrical short would leave
a transparent
region in electrochromic device 300 when it is in the colored state, similar
in appearance to
the visual defect created by the short described above in relation to Figure
2.
[0049] Pop-off defects due to particles or debris on the substrate, ion
conducting layer,
and on the counter electrode layer may also cause pinhole defects. Also, if a
contaminate
particle is large enough and does not cause a pop-off, it might be visible
when the
electrochromic device is in the bleached state.
[0050] The description above, as described in relation to Figures 1A, 1B,
2, and 3A-C,
presumes that there is a distinct ion conducting (electronically resistive)
layer sandwiched
between an electrochromic layer and a counter electrode layer in
electrochromic devices.
The description is only meant to be illustrative of how a particle can create
a short related
defect. That is, there are electrochromic devices where a distinct
electronically resistive and
ion conducting layer does not exist, but rather an interfacial region that
serves as an ion
conductive layer exists at the interface of the electrochromic and counter
electrode layers.
Electrochromic devices having this architecture are described in U.S. Patent
applications,
serial numbers 12/772,055 filed 4/30/2010, 12/772,075 filed 4/30/2010,
12/814,277 filed
6/11/2010, 12/814,279 filed 6/11/2010 and 13/166,537 filed 6/22/2011, each
entitled,
"Electrochromic Devices," each having inventors Wang et al., and each hereby
incorporated
by reference in their entirety. Thus particles can cause shorting defects in
these devices as
well, e.g., where the particle exists at and/or crosses the interface between
the electrochromic
and counter electrode layers and/or creates pop-off type defects as described.
Such devices
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are also susceptible to other defect types described herein, despite not
having a distinct IC
layer as in conventional devices.
[0051] Thus, there are three types of defects are of primary concern with
regard to
electrochromic windows: (1) visible pinholes, (2) visible shorts, and (3) non-
visible shorts. A
visible pinhole will have a defect dimension of at least about 100 pm, and
manifest as a very
small point of light when the window is colored, sometimes barely discernible
to the naked
eye, but visible upon close scrutiny. Typically, though not necessarily, a
visible short will
have defect dimension of at least about 3 micrometers resulting in a region,
e.g. of about 1 cm
in diameter, often referred to as a "halo," where the electrochromic effect is
perceptibly
diminished. These halo regions can be reduced significantly by isolating the
defect causing
the visible short so that to the naked eye the visible short will resemble
only a visible pinhole.
Non-visible shorts can affect switching performance of the electrochromic
device, by
contributing to the overall leakage current of the device, but do not create
discernible points
of light or halos when the window is in a colored state.
[0052] Embodiments described herein include apparatus and methods where
visible
defects are identified and mitigated. In certain embodiments, the visible
defect is due to a
visible short, i.e., a visible defect that produces a halo is identified and
mitigated. Visible
short defects that produce halos are described in more detail below.
[0053] Visible shorts produce a halo when the device is darkened. A halo is
a region in
the device where an electrical short across the electrochromic stack causes an
area around the
short to drain current into the short and therefore the area surrounding the
short is not
darkened. As mentioned, these regions can be up to about 1 cm in diameter, and
thus present
a problem by making the electrochromic window, when colored, unattractive to
the observer.
This frustrates the purpose of having windows that can operate in a colored
mode.
[0054] Conventionally visible short defects are mitigated after fabrication
of the
electrochromic device, but while still in the production facility, for
example, prior to
installation in an IGU. For example, individual electrochromic panes are
characterized by
first applying temporary bus bars and then coloring the electrochromic device.
Visual defects
such as halos are identified and then mitigated, for example, laser
circumscribed to isolate
them and remove the halo effect, which leaves smaller, less discernible,
pinhole defects. As
described above, conventionally, at least two, large, dedicated apparatus, are
used to carry out
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identification and mitigation of visual defects. However, defects can form in
the
electrochromic devices after the devices leave the production facility due to,
for example, the
inherent stresses in electrochromic devices (e.g. see above) and/or stresses
applied to the
windows during normal use such as installation, pressure differential between
interior and
exterior space, impacts that do not break the window pane and the like.
Conventionally, for
electrochromic windows already installed in a vehicle or building, mitigating
such defects
would not be done, rather the unit would be replaced in the field. This can be
very expensive.
As well, mitigating defects in existing electrochromic windows in the field
would greatly
extend the usable lifetime of the windows. Thus embodiments described herein
include
portable apparatus for identifying and mitigating visual defects.
[0055] PORTABLE DEFECT MITIGATORS
[0056] Embodiments described herein include apparatus and methods for
identifying and
mitigating visual defects in electrochromic or other devices where a visually
discernible
defect can be identified and mitigated as described herein. Such apparatus may
be referred to
herein as "defect mitigators," though their function includes components for
both identifying
and mitigating visual defects. In certain embodiments, apparatus for
identifying and
mitigating visual defects are portable. "Portable" in this context means that
such apparatus
can readily be moved and/or transported in order to identify and mitigate a
visual defect in an
electrochromic window or other device in the field, for example, an
electrochromic window
that is installed in a building, an automobile, and the like. That is, the
apparatus can be, for
example, carried by hand or otherwise manipulated by one or more users in
order to position
the apparatus proximate to an electrochromic window and carry out the
functions of
identifying a visual defect and mitigating the visual defect using the
apparatus.
[0057] Portable apparatus for identifying and mitigating visual defects in
electronic
devices, such as those used in flat panel displays, photovoltaic windows and
electrochromic
windows, provide significant advantages over large, dedicated apparatus in a
production
facility setting. In particular, the portability of the apparatus allows for
its use in the field,
including on installed devices. Due to inherent stresses in electronic devices
such as
electrochromic windows and/or stresses applied to the devices, defects can
form after the
devices leave the production facility. This is a problem, especially for
devices that are
installed in a permanent fashion, such as an electrochromic window installed
in a vehicle or
building. Typically, when such visual defects arise in an electrochromic
window, the
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window must be replaced. This can be costly, because electrochromic windows
have
associated wiring and related hardware. For example, recently, replacing four
defective
electrochromic windows in a prominent downtown London building was estimated
to cost
nearly Ã1 million. As well, avoiding replacement by mitigating defects in
existing
electrochromic windows in the field would greatly extend their usable
lifetime.
[0058] In certain embodiments, a portable apparatus will attach to the wall
and/or
window frame in order to carry out identification and mitigation of visual
defects in an
electrochromic window. In some embodiments, the portable apparatus will attach
to the
electrochromic window glass in order to identify and mitigate visual defects.
This mode of
attachment may be on a pane bearing an electrochromic device or a pane of an
IGU that does
not have an electrochromic device on it, e.g., defects are identified and
mitigated on one
pane, through another pane not having an electrochromic device. These and
other aspects of
embodiments are described in more detail below.
[0059] Some embodiments include an apparatus for mitigating a visual defect
in an
electronic device on a substrate, the apparatus including: a first mechanism
configured to
detect the visual defect; and a second mechanism configured to mitigate the
visual defect.
Apparatus described herein are particularly useful for identifying and
mitigating visual
defects where the electronic device on the substrate is an electrochromic
window pane. In
some embodiments, the first mechanism and second mechanisms are mounted on a
movable
stage, the movable stage configured to align the first and second mechanisms
over all or
substantially all of the viewable surface of the substrate. In one embodiment,
the movable
stage is an X-Y stage.
[0060] In some embodiments, the first mechanism includes an optical
instrument. The
optical instrument may be automated and thus include associated optical
processing software.
In one embodiment, the optical instrument includes at least one of a
microscope, a camera,
and a photo detector. For example, a microscope finds the center of a halo by
measuring the
relative intensity of light passing through the window (including any defects)
and zeroing in
on the maximum intensity region, which will typically be the center of the
halo, and which
also indicates the location of the defect to be remedied. Other types of
detection mechanisms
may rely on reflection or scattering of incident light (e.g. laser light, high
intensity lamps, or
ambient light). A microscope would typically be used during bright daylight
hours when
external radiation is impinging on the window undergoing defect detection;
however a bright
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light or other source of visible energy, e.g. a laser source, may be used to
illuminate the pane
from the other side during darker hours of the day.
[0061] In some embodiments, a dark field illumination technique may be used
to detect
defects. In dark field illumination, sample contrast comes from light
scattered by the sample.
A dark field illumination technique can work well for defect detection when
the defect causes
a bump or other surface irregularity on the substrate; the dark field
illumination technique can
improve the contrast of such defects. For example, in the case of an
electrochromic device
disposed on a lite, the defect could include a particle with layers of the
electrochromic device
deposited over it, forming a raised bump in the electrochromic device.
[0062] As shown in Figure 4, in dark field illumination, a substrate, 480,
may include a
particle, 481, creating an irregularity on the surface of substrate 480.
Illumination sources,
482 and 483, may illuminate particle 481 at a small glancing or grazing angle
(e.g., angles
484 and 485). An optical detector, 486, may detect light scattered from the
irregularity on the
surface of substrate 480. In some embodiments, dark field illumination employs
a lens or
other optical component to focus the scattered light onto optical detector
486.
[0063] Light incident upon the smooth regions of substrate 480 would
reflect at wide
reflection angles and would not be collected optical detector 486. In some
embodiments,
when multiple light sources or a circular light source (i.e., a light source
configured to shine
light from a perimeter of a circle onto a substrate) are used, the scattered
light may form an
image of the irregularity contour. In some embodiments, when a single or only
a few light
sources are used, the scattered light may give an indication of a surface
irregularity, but may
not form an image of the surface irregularity. In some embodiments, the first
mechanism
including components for dark field illumination may be on the same side of
the substrate or
lite as the second mechanism.
[0064] In some embodiments, the second mechanism includes at least one of a
laser, a
heat source, an induction coil, a microwave source, and a voltage source. If a
laser is used,
some thought must be given to ensuring the safety of those who might encounter
the laser
beam outside the building having a window where the remediation is being
performed. In
one embodiment, a laser having a very short focal length laser beam is used to
mitigate
defects so that any laser radiation passing outside the window will quickly
diffuse over a
wide area and become harmless. In one embodiment, laser energy is used to
circumscribe a
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visual defect in such a manner so that it penetrates at least through the
entire electrochromic
device, including the electrochromic materials and both transparent conducting
layers. The
penetration may or may not pass through a diffusion barrier (if present) on
the substrate. In
another embodiment, mechanisms that allow detection and remediation after dark
are used, so
that there is a much lower likelihood of escaping laser radiation injuring
citizens. In another
embodiment, an opaque material is draped over the opposite side of the window
upon which
remediation is to take place. In another embodiment, the laser is tuned so
that upon
encountering the EC device and while mitigating the defect, the remaining
energy of the laser
beam is scattered or otherwise made diffuse so that any energy traveling past
the window
pane is harmless.
[0065] In some embodiments, a combination laser backstop/illumination
device is used
when the second mechanism includes a laser. A laser backstop/illumination
device may be a
battery powered device that is attached to the opposite side of the window
from the laser
during defect mitigation. For example, an illumination device may be useful in
locating
visual defects in an electrochromic device disposed on a window. The
electrochromic device
may be transitioned to a colored state, with the illumination device on a
first side of the
window and an optical instrument for detecting defects may be on a second side
of the
window. The illumination device, by shining light though pinholes or other
visible defects in
the electrochromic device, may make such defects more visible. In some
embodiments, the
illumination device includes a diffused light emitting diode (LED) backlight,
a diffused
halogen lamp, or other means of projecting light directly through the
electrochromic device.
For example, in some embodiments, the illumination device may include optics
or
components that use ambient light, including ambient sunlight, for a light
source.
[0066] The illumination device is coupled with a laser backstop that may
include a safety
interlock. The illumination device would be protected against laser damage by
an optical
band-reject filter or other optical component that would block the wavelength
of
electromagnetic radiation of the laser.
[0067] In some embodiments, a laser backstop/illumination device and a
laser include an
active communication system. The communication system may be powered by a
battery.
For example, the communication system may include optical transceivers,
inductive
proximity detectors, or other means of wireless connection between the laser
backstop/illumination device and the laser. When the communication system
indicates that
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the laser backstop/illumination device and the laser are in close proximity to
one another, on
either side of the window, the laser backstop is in a position to block laser
light and the laser
is enabled. When the communication system indicates that the laser
backstop/illumination
device and the laser are in not close proximity to one another, the laser is
not enabled. The
default mode would be the laser not being enabled.
[0068] When using an apparatus for detecting and mitigating defects, with
the apparatus
including a laser backstop/illumination device, the apparatus could be
operated by a single
person or, for example, two or more people. For example, when one person is
operating the
apparatus, the user could attach the laser backstop/illumination device on an
outside of a
window on a building and then use the apparatus for mitigating defects. When
two people
are operating the apparatus, the people could work as a team; one person could
be on the
outside of the building and move the laser backstop/illumination device, and
one person
could be inside the building operating the apparatus.
[0069] In certain embodiments, apparatus described herein are portable.
Generally,
portable apparatus for identifying and mitigating defects should affix to or
otherwise be held
in position with respect to the window during operation. The associated
mechanism for
positioning may include, for example, a suction cup device that engages the
frame or other
structural feature around the window. In another mechanism, the apparatus is
mounted on a
rollable cart which has a vertically adjustable positioning mechanism for
positioning the
detection and remedying mechanisms during defect detection. This cart is
wheeled or
otherwise placed in position adjacent to a window undergoing defect detection
and
mitigation. Other positioning mechanisms are described below. In one
embodiment, a
portable defect mitigator is a handheld device having the features of a
portable defect
mitigator described herein.
[0070] Referring to Figure 5A, a portable defect mitigator, 400, is
depicted in
perspective. Defect mitigator 400 has a frame, 405, which houses an X-Y stage
including
rails 410 and 415, along with other drive components (not shown), which allows
base 430 to
be positioned horizontally and vertically within frame 405. In this example,
base 430 is
rotatable about a central axis as depicted, and supports a defect detector,
420, such as an
optical microscope, and a defect mitigator, 425, such as a laser. In this
example, detector 420
and mitigator 425 are both supported on an arm which connects to base 430. In
certain
embodiments, apparatus described herein also include components for
translating the defect
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detector and/or the defect mitigating component in the Z-direction, that is,
toward and away
from the window pane to be repaired. This may be necessary, e.g., when a laser
or other
focused beam mechanism is used to mitigate a defect in order to focus and/or
position
vertically within the stack, or attenuate the amount of energy applied to the
electrochromic
device.
[0071] Defect mitigator 400 also includes a controller, 440, in this
example an onboard
controller. In this example, electrical communication between controller 440
and detector
420 and mitigator 425 is hardwired as depicted. Base 430 has appropriate
electrical
connections, e.g., rotating electrical transfer components (commutator), which
allow it to be
rotatable while providing electrical communication between the components it
supports and
controller 440. Electrical communication between base 430 and controller 440
would also
include, e.g., wires housed within rails 415 and 420 and appropriate
electrical connections
that allow the rails to translate while maintaining the electrical
communication (the wires
may also be outside the rails with appropriate measure to prevent entanglement
with moving
parts of the apparatus). In other embodiments wireless communication between
the
controller and defect detector and mitigator components is used. As one of
ordinary skill in
the art would appreciate, controller 440 has appropriate logic to send
instructions to, and
receive instructions from, the defect detector and mitigator components 420
and 425.
Controller 440 may also contain memory, drivers for movement components, logic
and the
like.
[0072] In one embodiment, logic for controllers described herein includes:
a first
algorithm for scanning the electrochromic window pane with the first mechanism
in order to
detect the visual defect; and a second algorithm for positioning the second
mechanism
appropriately in order to mitigate the visual defect. In one embodiment, the
first algorithm
uses at least one of reflection, scattering and refraction, in order to
identify a defect signature.
The first algorithm may include instructions for scanning the entire surface
of the viewable
area of the electrochromic pane and assign coordinate data for each visual
defect identified.
The coordinate data may be stored in a memory and used by the controller to
send
instructions to the defect mitigator component. The coordinate system and
window pane
dimensions may be preprogrammed into the controller logic. In one embodiment,
the logic
includes instructions to scan the window to determine the window's viewable
area and then
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establish a coordinate system based on the dimensions of the window, and e.g.
the scanning
device's limitations and/or operating parameters.
[0073] In certain
embodiments, the second mechanism, the defect mitigator component,
includes a laser and the second algorithm includes instructions for guiding
the laser in order
to circumscribe damage to the electrochromic device which is the underlying
cause of the
visual defect. In certain embodiments, all of the coordinates of the
identified visual defects
are stored in a memory and this information is used by controller logic to
appropriately
position the defect mitigator component in order to circumscribe each defect.
The logic may
include instructions for identifying all the defects prior to any mitigation,
or, in some
embodiments, each defect is identified and then mitigated, before moving on to
identify more
defects. In one case, the logic may include metrics used in automated
identification of a
defect, type of defect, and prioritization of the defects for mitigation.
These metrics may be
based on the size, shape, centroid location, and other characteristics of the
defects.
[0074] As noted
on the right hand side of Figure 5A, apparatus 400 includes feet, 435,
which attach frame 405 to, e.g., a wall in which an electrochromic window,
450, is installed.
In this example, frame 405 of apparatus 400 is larger than window 450 so that
the X-Y stage
can be manipulated to position defect detector 420 and defect mitigator 425
over all areas of
the glass of electrochromic window 450 in order to scan for and mitigate
visual defects
wherever they may be on the viewable area of the glass pane bearing the
electrochromic
device to be repaired (movement in the Z direction can be preset and defined
once apparatus
400 is in place and/or in one embodiment there is a Z-positioning mechanism
for 420 and/or
425). Feet 435 may be, e.g., suction cups, pressure-sensitive adhesive pads
and the like. In
certain embodiments, it may be necessary to attach apparatus 400 to the wall
or window
frame in a more secure fashion, e.g. via a temporary support such as one or
more wall
anchors, a z-bar or the like. Apparatus 400 may also include clamps, hooks or
other
components that allow it to hang over a window frame, support itself by
clamping between
bricks along a mortar line, and the like. In some embodiments, apparatus 400
is supported by
legs, a tripod, a stand, a table, a cart or the like, whether or not it is
also supported by a wall.
In one embodiment, apparatus 400 is supported by one or more vertical
supports, such as
posts, where the posts are compressively positioned between the floor and
ceiling, whether or
not apparatus is also supported by a wall. One of ordinary skill in the art
would appreciate
that combinations of support mechanisms are within the scope of embodiments
described
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herein. Polymeric suction cups, pressure-sensitive adhesive pads and other
similar
attachment mechanisms have the advantage of simplicity and dampening any
vibrations that
might otherwise travel between apparatus 400 and the surface to which it is
affixed.
[0075] In one embodiment, the apparatus, e.g. as described in relation to
Figure 5A, does
not affix to the wall or window, but rather frame 405 is movable along tracks
or rails so that it
can be moved, or via appropriate movement mechanisms. This is illustrated in
Figure 5B. A
wall, 460, contains a number of windows in a linear arrangement, in this
example a horizontal
arrangement, but it could also be a vertical arrangement. A system of rails,
455, is
established, e.g., affixed to wall 460, or e.g., compressed between adjoining
walls to wall
460, or e.g. supported by stands at distal ends of the rails, etc. Rails 455
may have a circular
cross section as depicted, or have rectangular, triangular or other geometric
cross sections for
added strength and decreased tendency to bend or otherwise deform while
apparatus 400 is
operating thereon. Apparatus 400, via appropriate movement mechanisms, "walks"
along
rails 400, scanning each window 450, identifying visual defects and mitigating
them. This
configuration has the advantage that an initial set up of the rail system will
allow the
apparatus to repair a number of windows, e.g. in a curtain wall, automatically
without having
to perform an alignment of apparatus 400 for each window individually. In one
embodiment,
apparatus 400 travels along rails or tracks 455 where contact with the rails
is made via wheels
having a polymeric component, e.g. polymeric wheels or hard wheels with a
polymeric
covering, such as nylon or silicone in order to minimize vibration during
identification and
mitigation. Although apparatus 400 in its entirety is not typically moving
during
identification and mitigation of defects, there may be vibration from the wall
or other
building component to which the rail system is attached.
[0076] As mentioned, in this example, apparatus 400 is larger than
electrochromic
window pane in window 450 for the described reasons. In one embodiment, the
largest
dimension of the apparatus is not substantially larger than the largest
dimension of the
electrochromic window pane. In one embodiment, the largest dimension of the
apparatus is
not more than about 20% larger than the largest dimension of the
electrochromic window
pane, in another embodiment, not more than about 10% larger than the largest
dimension of
the electrochromic window pane. In certain embodiments, described in more
detail below,
the largest dimension of the apparatus is the same or smaller than the largest
dimension of the
electrochromic window pane to be repaired. In one embodiment the apparatus is
smaller than
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the electrochromic pane for which it is intended to repair. That is, the
dimensions described
above are meant to provide a metric for apparatus that use some form of
attachment to a
window and/or a wall, or that otherwise have a frame that is aligned in some
way with the
window to be repaired, for example, a frame containing an X-Y stage as
described. As
described above, in certain embodiments, apparatus are supported by a tripod,
a cart, a table
or the like, that does not affix to a window or wall.
[0077] In one embodiment, a handheld defect mitigator includes a defect
detector, a
defect mitigator and a controller, each as described herein, in a handheld
configuration. A
handheld defect mitigator may require two hands or only one hand to operate.
Typically, but
not necessarily, the handheld defect mitigator includes Z-direction
positioning mechanism,
which can be adjusted to particular needs, e.g., when mitigating through a non-
EC pane of an
IGU or directly through only the EC pane of the IGU. A handheld defect
mitigator may have
suction cups or adhesive pads to secure the apparatus to the glass at least
during mitigation.
In this context, a handheld defect mitigator may not use and/or include an
automated X-Y
positioning mechanism, but rather would rely on hand positioning at least to
initially position
the apparatus over a defect. After initial positioning, there may be some
finer positioning
hand operated mechanisms to move in the X-Y plane, such as thumbscrew
adjustments and
the like, to zero in on a defect. The optical instrument (e.g. a microscope)
and mitigating
mechanism (e.g. a laser) may be manually operated, or automatic once in
position.
[0078] In some embodiments, a portable defect mitigator has an optical
system with an
optical detector, a laser and/or an illumination source sharing a coaxial
optical path. Figure
5C is a schematic drawing of components of a portable defect mitigator having
an optical
system 550 including a laser 555 and an optical detector 560. In this
illustrated example,
laser 555 and optical detector 560 having a co-axial optical path. In some
cases, optical
detector 560 includes a charge coupled device (CCD). Also shown in Figure 5C
is an IGU,
565, including two panes or lites, with an electrochromic device, for example,
disposed on a
surface, 570. The optical components of optical system 550 further include a
first minor,
575, a dichroic mirror, 577, and lenses, 579 and 581. Lens 579 may be an
objective lens and
lens 581 may be a condensing lens.
[0079] In operation, the electrochromic device disposed on surface 570 of
IGU 565 may
be transitioned to a colored state. An illumination device, 585, may be
positioned to shine
light though any defects in the electrochromic device. Light from illumination
device 585
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would reflect from first mirror 575 about 90 degrees, pass though lens 579,
pass though
dichroic mirror 577, pass though lens 581, and form an image of the defect
that is detected by
optical detector 560. Dichroic mirror 577 is specified such that the
wavelength or
wavelengths of light from illumination device 585 pass though the dichroic
mirror. When
optical detector 560 detects a defect, the defect may then be mitigated with
laser 555.
[0080] In this example, light from laser 555 would reflect from dichroic
mirror 577 about
90 degrees, pass though through lens 579, reflect from first mirror 575 about
90 degrees, and
then impinge on surface 570. Dichroic mirror 577 is specified such that the
wavelength of
light from laser 555 is reflected by the dichroic mirror. Lens 579 focuses the
light from laser
555 to a focal point on or near to surface 570 to concentrate the energy of
the light to mitigate
the defect.
[0081] Lens 579 may be adjusted to change the focal point of both laser 555
and optical
detector 560. The focal plane of both the laser and the optical detector would
be finely tuned
to match by adjusting the position of lens 581. Thus, optical system 550 and
other similar
optical systems with a laser and an optical detector having a coaxial optical
path allows the
laser to be aimed at a defect and provides accurate alignment between the
detection and
mitigation processes.
[0082] In some embodiments, optical system 550 has a low mass. Because
optical
system may be mounted directly to a window, it is desirable to keep both the
mass of the
system and the moment perpendicular to the window low to prevent deflection of
the window
during operation of the system. For example, laser 555 may include a fiber
coupled input
with a low mass presenting a small perpendicular moment, with the laser source
being
mounted elsewhere (i.e., not on the window). Further, with one lens, lens 579,
used to focus
both laser 555 and optical detector 560, a single motor may be used to adjust
the lens,
reducing the mass of optical system 550. Optical system 550 may be positioned
close to IGU
565 or other window while still keeping the majority of the mass along the
vertical axis of the
window.
[0083] One goal of the coaxial optics in optical system 550 is for the
detection path and
the laser path to "see" the defective surface as identically as possible. This
facilitates the
precise removal of the defect with minimal error in laser alignment. Even with
coaxial
optics, however, there may be alignment errors of the laser focal point
associated with
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diffraction through the glass of the IGU, aberrations in a lens, glass
warpage, the wavelength
dependence of optics in the optical system, etc. These errors may create an
offset between
the center of the detection optics path and the center of the laser optics
path, leading to laser
alignment errors.
[0084] To remedy this, in some embodiments, optical system 550 may include
a
controller including program instructions for conducting a process. The
process may include
a low power firing sequence with the laser to ensure that the laser focal
point is at the position
of the detected defect. For example, in some embodiments, optical system 550
is aligned on
a defect using the optical detector 560. Then, laser 555 emits light at a low
power to create a
visible spot of light on surface 570 which is reflected and imaged by optical
detector 560.
There may be an offset between where the defect is detected by optical
detector 560 and the
visible spot of light from laser 555 as shown in diagram 590 of Figure 5D. The
controller
can then determine the exact positional offset between where the laser light
is intended to
intersect surface 570 during defect mitigation and where it actually will
intersect surface 570.
The alignments of optical system 550 is then adjusted to correct for any error
in alignment
prior to firing the laser at high power to mitigate the defect, as shown in
diagram 595 of
Figure 5D.
[0085] Referring to Figure 6, a portable defect mitigator, 500, is depicted
in perspective.
Unlike defect mitigator 400, defect mitigator 500 does not have a frame, or an
X-Y stage
along with other drive components. Like apparatus 400, apparatus 500 does have
a base 430
which is rotatable about a central axis as depicted, and supports a defect
detector, 420, such
as an optical microscope, and a defect mitigator, 425, such as a laser. In
this example,
detector 420 and mitigator 425 are both supported on an arm which connects to
base 430.
Base 430 is supported by a column, 505. Column 505 is movable along a vertical
axis
through an aperture in a body 515. Body 515 houses a controller 525, similar
to controller
440 described above. In this example, via a drive mechanism, 510, column 505
is translated
vertically, up or down through body 515, which is stationary and rests on legs
520.
Controller 525 has a logic that performs the identification and mitigation of
defects as
described above in relation to apparatus 400; however, the movement algorithms
for
positioning detector 420 and mitigator 425 are different with respect to
column 505 as
compared to apparatus 400 which has an X-Y stage movement assembly (movement
in the Z
direction can be achieved manually in this case by appropriate placement of
the tripod). In
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certain embodiments, which is true for all apparatus described herein,
positioning, scanning
and mitigation commands can be input manually, e.g., via a keypad or other
input device on
the controller. In some embodiments, once the apparatus is positioned and/or
aligned, these
functions are fully automated, that is, the apparatus automatically scans the
window pane,
identifies the visual defects according to programmed criteria and mitigates
the visual
defects. Apparatus 500 may also include components for translating the defect
detector
andlor the defect mitigating component in the Z-direction, that is, toward and
away from the
window pane to be repaired as described in relation to apparatus 400.
[0086] During operation, apparatus 500 is positioned and aligned
appropriately in front of
window 450 so that detector 420 and mitigator 425 can scan and identify and
mitigate visual
defects across the entire viewable area of electrochromic window 450.
Apparatus 500 has the
advantage of being compact relative to, e.g., an apparatus having a large
frame and X-Y
stage, e.g., legs 520 may be telescopic and foldable when not in use.
[0087] In some embodiments, the largest dimension of the apparatus is
smaller than the
largest dimension of the electrochromic window pane and the apparatus mounts
to the
electrochromic window that includes the electrochromic pane during operation.
In one
embodiment, the apparatus mounts to the window pane (glass) itself, without
having to touch
the window frame or wall. In this embodiment, the apparatus may attach to the
window via
at least one of a suction cup and a pressure-sensitive adhesive. This may
include a handheld
defect mitigator as described herein (e.g. an apparatus not having an X-Y
stage positioning
components).
[0088] Referring to Figure 7, a portable defect mitigator, 600, is depicted
in perspective.
Like defect mitigator 400, defect mitigator 600 has a frame, and an X-Y stage
along with
other drive components. Also, like apparatus 400, apparatus 600 has a base
605; however
base 605 is non-rotatable. In this example, base 605 is a frame through which
the detector
component can scan the pane of window 450 to locate and identify visual
defects and the
mitigator component can mitigate the defects. The X-Y stage in apparatus 600
moves base
605 about the area inside the frame 615 of apparatus 600. Although apparatus
600 cannot
identify and mitigate defects over the entire area of window 450 while in a
single position, it
has the advantage of being small and more easily ported to the jobsite. In
some instances, a
customer might have only a few halo effects on a window, or windows, and such
an
apparatus would be more easily positioned over the halo in question for
remediation efforts.
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In this example, referring to expanded portion X in Figure 7, wireless
communication is used
between detector/mitigator components and controller 610. One embodiment is
any
apparatus described herein, e.g. apparatus 400 or 500, further including
wireless
communication between the detector and/or mitigator and the controller. One of
ordinary
skill in the art would appreciate that such apparatus would include
appropriate wireless
antennae, receivers and transmitters. The controller need not be affixed to
the frame or other
component of the apparatus; rather it can be in the form of a remote control
device.
[0089] One embodiment is a method of mitigating a visual defect in an
electrochromic
window installed in a building or an automobile, the method including: (a)
identifying the
visual defect in the electrochromic window; and (b) mitigating the visual
defect using at least
one of a laser, a heat source, an induction coil, a microwave source and a
voltage source. In
one embodiment, the electrochromic window is colored prior to (a) or as part
of the
identification process. Apparatus as described herein are particularly useful
for implementing
methods described herein.
[0090] Figure 8A depicts aspects of a method, 700, which begins with
identifying a
visual defect, see 705. As described, apparatus described herein, once
positioned
appropriately, may scan an electrochromic pane in order to locate and identify
visual defects.
Figure 8B outlines an embodiment of process flow 705. First the electrochromic
pane is
colored, see 715. The defect detector is then positioned with respect to the
pane, see 720.
Steps 715 and 720 may be done in reverse order or simultaneously. If the pane
is already
colored, then step 715 is optional. Next, the electrochromic pane is scanned,
see 725. As
described above, this may be accomplished with controller logic having
instructions for
particular scanning algorithms. Optionally, the coordinates of the visual
defect may be stored
in a memory, e.g., part of the controller, see 730. Next, e.g. when a
controller logic is used,
the coordinates of the visual defect may be communicated to the defect
mitigator mechanism,
see 735. Then the identification operations end.
[0091] Referring back to Figure 8A, after the visual defect is identified,
it is then
mitigated using the mitigation mechanism, see 710. Figure 8C outlines an
embodiment of
process flow 710. Assuming the visual defect's coordinates were sent to, e.g.
a mitigation
mechanism, the data is received by the mitigation mechanism, see 740. The
defect mitigation
mechanism is then positioned with respect to the electrochromic pane
appropriately to
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mitigate the defect, e.g., circumscribe the defect with a laser, see 745. Once
positioned, the
defect is mitigated, see 750. Then the process flow ends.
[0092] In certain embodiments, a laser is used to mitigate a defect.
Electrochromic
windows may have an EC device on the inner surface of the outer (on the
outside of a
building) pane of glass, while the inner pane does not have an associated EC
device. Lasers
are particularly useful for mitigation because they can be tuned so that the
laser beam is
passed through the inside pane of glass in order to mitigate a defect in the
EC device on the
outer pane (e.g. inside a window unit, two panes with a separator between
them, e.g. a simple
IGU). One embodiment is a method of mitigating a visual defect in an
electrochromic device
on a glazing that is part of a window unit, the method including: (a)
identifying the visual
defect in the electrochromic device; and (b) mitigating the visual defect
using a laser. In one
embodiment, the electrochromic device is colored prior to (a) or as palt of
the identification
process. In one embodiment, the window unit is an IGU having a first and a
second pane
(glazing), where the first pane bears an electrochromic device and the second
pane does not
have an electrochromic device thereon. In one embodiment, the laser energy is
passed
through the second pane and a defect in the electrochromic device on the first
pane is
mitigated. In one embodiment, the laser energy is passed through the first
pane and a defect
in the electrochromic device on the first pane is mitigated.
[0093] Mitigating defects using laser energy that passes through a pane of
an IGU,
through the volume of the IGU and ablates an electrochromic device on an
opposing pane is
different than mitigating defects in an electrochromic device sealed in a
laminated structure,
e.g., as described in U.S. Patent No. 7,531,101. For example, in such
laminated structures,
there is necessarily an interlayer material such as a thermoplastic polymer
material that binds
the substrates together. This material can affect the ability to ablate an
electrochromic device
if the laser energy must pass through the interlayer material, for example the
interlayer
material may be an absorber of the laser energy. For example PVB and
polyurethane
interlayer materials may absorb certain wavelengths of energy. Also, due to
the distance
between the panes of an IGU in the volume of the IGU, the focal distance,
power and choice
of laser may vary considerably.
[0094] In certain embodiments, apparatus and methods herein are used to
identify and
mitigate defects in electrochromic windows that have at least one EC device on
both the inner
and the outer pane of the IGU. Electrochromic windows having this architecture
are
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described in U.S. Patent application, serial number 12/851,514, filed
8/5/2010, and entitled,
"Multi-pane Electrochromic Windows," by Friedman et al., which is incorporated
by
reference herein in its entirety. When defects in such windows are mitigated,
for example a
window having one EC device on each pane of an IGU, identification and
mitigation of
defects are typically, but not necessarily, carried out while one pane's EC
device is bleached
so that the other pane's EC device can be colored and any defects identified
and mitigated.
Once one pane's defects are mitigated, the EC device on the processed pane is
bleached and
the other pane is colored in order to carry out identification and mitigation
operations on that
pane. Identification and mitigation may be carried out from a single side of
the window, for
example the interior of the building, because the inner pane can be bleached
and the laser
tuned to pass through the bleached pane and mitigate the outer pane's colored
EC device.
[0095] DYNAMIC AUTOFOCUSING SYSTEM
[0096] Although windows are substantially rigid, they may have some degree
of flex
under certain circumstances. For example, an electrochromic window,
particularly a large
electrochromic window, may flex somewhat while being installed and when
subject to
external forces such as wind. If an electrochromic window flexes during the
course of defect
imaging and mitigation, the maximum flux of radiant energy at the focal point
of the laser
may not remain aligned to the targeted portion of the window. Typically, the
focal point
should be targeted to a position at or very near the surface of the
electrochromic device near
the defect. If the focal point of the laser does not remain aligned to the
targeted location,
defect mitigation (and/or imaging) may become less effective. Dynamic
autofocus systems
disclosed herein can be employed by the defect mitigator to help ensure that
the focal point of
the laser remains consistently aligned to the targeted location even while the
window may be
flexing or otherwise moving over the course of the imaging and mitigation
process.
[0097] One way that a dynamic autofocus system can address this challenge
is by
automatically adjusting the position of a lens to focus the laser light to the
targeted location as
the window flexes or otherwise moves during defect imaging and/or mitigation.
For
example, the lens can be automatically adjusted to maintain the lens at a
particular separation
distance D (e.g., a distance at about a focal length of the lens from the
surface) from the
targeted location or maintain the lens within a range of distances from the
particular
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separation distance D from the target location. The target location is
typically at a surface of
the electrochromic device having the defect.
[0098] In some cases, these automatic adjustments can be accomplished with
a suitably
fast feedback/control system. This system includes a processor (e.g.,
microprocessor) that
sends signals to a lens positioning mechanism capable of moving the lens in
response to
certain detected movements of the surface of the clectrochromic device or
other suitable
portion of the window. The processor is in communication with a detecting
mechanism that
detects these movements.
[0099] During defect mitigation, the processor may receive signals with
data from the
detecting mechanism. The data may include the location of the surface or other
portion of the
window at the time of detection. The processor may determine the current
separation
distance D and/or the movement of the window since the last sampling time. The
processor
may then determine whether the current separation distance D (or movement) at
the time of
detection requires that the lens move to correct the position of the focal
point at the targeted
portion of the window. For example, the processor may determine whether the
difference
between the current separation distance D and the focal length of the lens is
more than certain
percentage difference (e.g., .001%, .01%, .1%, 1%, 2%, etc.) to determine
whether the
difference is within an acceptable range. As another example, the processor
may determine
whether the difference between the current separation distance D and the focal
length of the
lens is more than a maximum difference (e.g., .01mm, .1mm, .2mm, etc.) to
determine
whether it is within an acceptable range. If the surface has moved out of the
acceptable
range, the processor determines a new location of the lens with a separation
distance D within
the acceptable range. For example, the new location may be a distance (from
the current
location) equal to the measured separation distance D less the focal length.
The processor
then sends a control signal to the lens positioning mechanism 1020 to move the
lens to the
new location. Dynamically adjusting the lens to maintain the separation
distance D within
this acceptable range, keeps the laser in focus substantially locating the
focal point at the
target location for mitigating the defect. The acceptable range may be related
to the size and
centroid location of the focal point of the laser being employed.
[0100] In some instances, there may be a significant lag time between the
sample time at
which the separation distance is measured and the time at which the lens has
moved to the
new location. To lessen the impact of such a lag time, certain embodiments of
the portable
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defect mitigator may include a processor that can predict a separation
distance D at a future
time based on measurements from the detection mechanism (e.g., triangulation
sensor) taken
at one or more sample times. In these cases, the detection mechanism may
determine the
separation distance D and a rate of change of the separation distance D at a
sample time. The
processor can determine the future separation distance D at a future time
based on the
separation distance D and rate of change measured at the sample time. If the
surface is
predicted to move out of the acceptable range by the future time, the
processor can determine
a new location of the lens with a separation distance D within the acceptable
range that is
appropriate for the future time. The processor then sends a control signal to
the lens
positioning mechanism 1020 to move the lens to the new location and the lens
moves to the
new location by the future time.
[0101] Figure 9 is a schematic illustration of a mitigation process using a
dynamic
autofocus system 1000, according to embodiments. In this example, the
mitigation process is
being performed on a window unit 910 having a first electrochromic window pane
920(a), a
second electrochromic window pane 920(b), and a sealing separator 930 between
the first and
second panes 920(a), 920(b). The first electrochromic window pane 920(a) has a
first
surface 922(a) and a second surface 922(b). The second electrochromic window
pane 920(b)
has a first surface 924(a) and a second surface 924(b). Each of the
electrochromic window
panes 920(a), 920(b) includes an electrochromic device on one side or both
sides of a
substantially transparent sheet (e.g., glass sheet). The illustrated window
unit 910 may be
part of an 1GU. Although an electrochromic window is shown in Figure 9 and
other
illustrated embodiments, any window with an optically switchable device can be
used.
[0102] In Figure 9, a wind force 1010 is impinging the second surface
924(b) of the
second electrochromic window pane 920(b). The wind force 1010 is causing the
window
unit 910 to bend and bow inward at the center portion. The illustration shows
the window
unit 910 at two instances before flexing 910(1) (at time to) and after flexing
910(2) (at time ti
occurring during the mitigation process). Although a wind force is used in
embodiments,
other forces may cause deformation of the window panes. For example, building
vibrations
from a train or construction may cause deformation.
[0103] The illustrated dynamic autofocus system 1000 includes a lens
positioning
mechanism 1020, a detection mechanism 1030, and a processor 1040 in
communication with
the lens positioning mechanism 1020 and the detection mechanism 1030. A laser
(not
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shown) provides a collimated laser beam 1050 used to mitigate the defect. The
lens
positioning mechanism 1020 is in communication with a lens 1060 used to focus
the
collimated laser beam 1050 to a focal point 1070. The focal point 100 is
located at or near a
target location for mitigating the defect. In this example, the target
location is at the second
surface 924(b) of the second electrochromic pane 920(b). In other embodiments,
the target
location may be at other locations of the window unit 910.
[0104] During the mitigation process illustrated in Figure 9, the detection
mechanism
1030 measures the location of the second surface 924(b) and/or another surface
(e.g., 924(a),
922(a), 922(b)) at different sampling times, t1, t2,...,tn. Alternatively, the
detection
mechanism 1030 may measure the location of the target portion. At each
sampling time, the
detection mechanism 1030 sends signals to the processor 1040 with the location
data. In the
illustration, the detection mechanism 1030 measures the location of the second
surface
924(b) near the defect at time t1 and sends signals with data to the processor
1040 with the
location at time t1. The processor 1040 sends control signals to the lens
positioning
mechanism 1020 to move the lens 1060 from a first position to a second
position along a z-
axis located along the centerline axis of the collimated laser beam 1050. This
movement
keeps the separation distance D between the target location at the second
surface 924(b) and
the lens 1060 to a constant value equal to the focal length to keep the focal
point 942 at the
second surface 924(b) during the mitigation process. In other examples, the
detection
mechanism 1030 may detect a location on multiple surfaces or other surfaces of
the window.
In some cases, the surface detected by the detection mechanism 1030 may
correspond to the
closest surface to the defect.
[0105] As explained, the maximum flux of radiant energy (at the focal
point) should be
located at the targeted portion of the electrochromic device to be mitigated.
Another possible
way to address this challenge involves using a laser beam that is relatively
insensitive to
changes in distance D. Such a beam would have a relatively long focal point
(i.e., long in the
direction of beam propagation). The focal point length would be great enough
to permit
mitigation over the full range of variations in D encountered during movement
of the
electrochromic window. The length of the beam that provides a relatively
invariant radiant
energy flux (the focal region) is sometimes referred to as the "depth of
focus" of the beam.
Achieving a depth of focus of greater than about 500 um (i.e., greater than
1000 gm total
depth) is typically problematic. A depth of focus this great may make the spot
area of the
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laser beam too great to effectively scribe. Further, the separation distance
of the laser optics
(e.g., the condensing lens) from the tool may be too great. In some
embodiments, suitable
depth of focus ranges are about I00 um or less, or about 50 iLtm or less.
Therefore, the
depth of focus of a laser is typically too short to allow the system to
operate without adjusting
the lens position in order to maintain a separation of D.
[0106] Various possible focus control mechanisms that can be employed as a
detection
mechanism 1030 in the dynamic autofocus system to ensure that the focus of the
laser
remains focused during mitigation at the proper height (e.g., z-position in
Figure 9) through
the thickness of the window. One type of design employs confocal detection and
patterning
beams. A detection beam is used to deteimine the distance between the surface
of interest
and a frame of reference. Generally a confocal system is one where the
patterning and
detection beams (or any other two beams) share the same focal point. They may,
in some
embodiments, share the same optics.
[0107] Another type mechanism that may be used as a detection mechanism
1030 in the
dynamic autofocus system 1000 is a triangulation sensor. Some examples of
triangulation
sensors that can be employed as detection mechanisms 1030 can be found in U.S.
Patent
application No. 13/436,387, filed on March 30, 2012, which is hereby
incorporated by
reference in its entirety. Figure 10 illustrates an example of a triangulation
sensor 1132 that
can be used as a detection mechanism in the dynamic autofocus system,
according to
embodiments. The triangulation sensor 1132 includes a laser 1133 and a
detector 1134. In
some embodiments, laser 1133 may be a lower power laser that does not scribe
or melt a
substrate, but is reflected from the substrate. In many cases, the laser 1133
is a blue laser. In
some cases, the detector 1134 may be a charge coupled device (CCD). Detector
1134 is
positioned to face a direction at a fixed angle from laser beam path. The
triangulation sensor
1132 may be mounted to the same block that holds the focal lens.
[0108] In operation, triangulation sensor 1132 projects a laser beam from
laser 1133 onto
a surface of an electrochromic window. The laser beam is reflected from the
surface and
onto different regions of detector 1134. From the region of detector 1134 that
the laser beam
is reflected onto, the distance of the surface of the electrochromic window
from triangulation
sensor 1132 can be determined. For example, as the electrochromic window moves
in the z-
direction along a z-axis at the centerline of the laser beam propagation, the
lateral movement
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as detected by detector 1134 is converted to a distance reading between
triangulation sensor
1132 and the surface of the electrochromic window.
[0109] Triangulation sensor 1132 can determine a distance of a surface of
the
electrochromic window from triangulation sensor 1132 and or the distance of
the surface of
the electrochromic window to the focal lens of the dynamic autofocus system
1000. For
example, triangulation sensor 1132 may determine a nominal distance so from
the surface at a
position 1136 at height of z = 0 where the electrochromic window is in a
baseline state (not
flexing or otherwise moving). As another example, triangulation sensor 1132
may determine
a distance si from the surface at a position 1137 at height of z = +zi where
the electrochromic
window flexed and the position has moved in the positive z-direction by z1. As
another
example, triangulation sensor 1132 may determine a distance s2 from the
surface at a position
1138 at height of z ¨ -zi where the electrochromic window flexed and the
position has moved
in the negative z-direction by zi. In some cases, the triangulation sensor
1132 may be
restricted to measuring distances between a minimum distance and a maximum
distance. In
these cases, the triangulation sensor 1132 may be set or calibrated based on
the nominal
distance.
[0110] In one embodiment, the dynamic autofocus system adjusts the focus
lens 1060
such that the beam emitted from the laser impinges a second side of the second
side of the
electrochromic pane and is focused at the interface of the first side of the
electrochromic pane
and the electrochromic device, as determined by the triangulation-based
distance sensor
1132. For example, a feedback loop may be implemented such that the focus lens
1060
adjusts rapidly based on the determination by the triangulation-based distance
sensor. In
some embodiments, a signal from the triangulation-based distance sensor 1132
may be an
analog signal which may aid in enabling the rapid adjustment of the focus lens
1060.
[0111] EXAMPLES OF HANDHELD PORTABLE DEFECT MITIGA TORS
[0112] In some embodiments, the portable defect mitigator may be a handheld
design that
can be affixed directly to the surface of the window during defect imaging and
mitigation.
These handheld defect mitigators may include one of the optical systems
disclosed herein.
Optical systems with components in a compact arrangement that may be
particularly suitable
for such a handheld design are shown in Figures 11A, 11B, and 12.
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[0113] In Figures 11A and 11B, an optical system 1200 includes an optical
detector 1210
(e.g., a charge coupled device (CCD), Complementary metal¨oxide¨semiconductor
(CMOS)
sensor, etc.), an illumination device 1212, and a laser 1220 serving as a
defect mitigator.
Both laser 1220 and illumination device 1212 provide collimated light. Optical
system 1200
also includes a first lens 1230, a mirror 1234, a first dichroic mirror 1240,
a second dichroic
mirror 1250, and a second lens 1260. As shown, optical detector 1210,
illumination device
1212, and laser 1220 share a coaxial optical path between first dichroic
mirror 1240 and
mirror 1234 and also between mirror 1234 and first lens 1230. Second lens 1260
may be a
condensing lens. First lens 1230 may be an objective lens.
[0114] Figures 11A and 11B also include an IGU 1270 with a defect (not
shown) being
imaged and mitigated. The IGU 1270 has a first lite 1272 (first pane) and a
second lite 1274
(second pane) with an electrochromic device disposed on a surface 1276 of the
second lite
1274. The defect (not shown) being mitigated is located on the surface 1276 of
the second
lite 1274. In a defect imaging and mitigation operation, the electrochromic
device disposed
on surface 1276 of IGU 1270 may be transitioned to a colored state.
[0115] During the imaging and mitigation operation illustrated in Figures
11A and 11B,
illumination device 1212 provides collimated illumination light. The
illumination light is
reflected at about 90 degrees from the second dichroic mirror 1250, and then
reflected at
about 90 degrees from first dichroic mirror 1240, and then reflected at about
90 degrees from
mirror 1234 to first lens 1230 which focuses the illumination light. The
focused illumination
light passes through the first lite 1272 to the second lite 1274 of the IGU
1270. Illumination
light reflected from the second lite 1274 to mirror 1234 will be reflected at
about 90 degrees
from mirror 1234 and then reflected at about 90 degrees from the first
dichroic mirror 1240.
This light passes through the second dichroic min-or 1250 to second lens 1260.
Second lens
1260 focuses the reflected light to the optical detector 1210. The optical
detector 1210 can
form an image of the defect based on light reflected from the defect area.
[0116] In Figures 11A and 11B, the laser 1220 emits light for mitigating
the defect. The
light from laser 1220 passes through the first dichroic mirror 1240, and is
reflected at about
90 degrees from mirror 1234 to the first lens 1230. The first lens 1230
focuses the mitigating
light to a focal point. The first dichroic mirror 1240 is specified such that
the wavelength or
wavelengths of light from laser 1220 passes through the first dichroic mirror
1240. The
second dichroic mirror 1250 is specified such that the wavelength or
wavelengths of light
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from illumination device 1212 is reflected by the dichroic mirror 1250. First
lens 1230
focuses the collimated light from laser 1220 to a focal point at or near
surface 1276 to
concentrate the energy of the light to a targeted portion to mitigate the
defect. First lens 1230
also focuses the collimated light from illumination device 1212 to a focal
point on or near to
surface 1276. In this optical system 1200, there is a common axis (coaxial
path) of the laser
and illumination light from the first dichroic mirror 1240 to the minor 1234
and from the
mirror 1234 through the first (focal) lens 1230, and then to the focal point.
[0117] In Figures
11A and 11B, minor 1234 and first lens 1230 can be rotated together
about a pivot point (or alternatively about one or more rotating axes) to
direct the light from
first lens 1230 at different angles. This rotation allows the light to be
directed at angles to be
able to locate the focal point, for example, under a spacer at the edge of an
IGU or to the
corner of the IGU. In Figure 11A, mirror 1234 and first lens 1230 are located
at a nominal
position to direct the optical path at about a 90 degree angle to a plane
substantially parallel
to the surface 1276. In Figure 11B, mirror 1234 and first lens 1230 are tilted
upward to
direct the optical path at an angle with respect to the plane substantially
parallel to the
surface 1276.
[0118] As shown,
light from laser 1220 and illumination device 1212 is collimated and
along a coaxial path to the first lens 1230. Since the light received at the
first lens 1230 is
collimated and coaxial, the first lens 1230 can focus both the mitigating and
imaging light to
an aligned focal point. Also, moving the first lens 1230 along the optical
path axis can
control the location of the focal point of both the laser light and imaging
light. That is, the
position of the first lens 1230 along the coaxial optical path can be adjusted
to finely focus
laser 1220, optical detector 1210, and illumination device 1212. The optical
system 1200 and
other similar optical systems having a coaxial optical path of collimated
light allow the laser
to be aimed at the defect and provide accurate alignment of the detection and
mitigation
processes. In these optical systems, laser 1220, optical detector 1210, and
illumination
device 1212 can be automatically focused with a dynamic autofocus system
disclosed herein.
To illustrate this aspect, Figures 11A and 11B also include a dynamic
autofocus system 1000
having a lens positioning mechanism 1020, a detection mechanism 1030, and a
processor
1040 in communication with lens positioning mechanism 1020 and detection
mechanism
1030. Lens positioning mechanism 1020 is in communication with the first lens
1230 to
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move the first lens 1230 to maintain the focal points at the same distance
from the first lens
1230 as the IGU 1270 may flex or otherwise move during the process.
[0119] In Figure 12, an optical system 1201 includes an optical detector
1210 (e.g., a
charge coupled device (CCD), complementary metal¨oxide¨semiconductor (CMOS)
sensor,
etc.), an illumination device 1212, and a laser 1220 serving as a defect
mitigator. Both laser
1220 and illumination device 1212 provide collimated light. Optical system
1200 also
includes a first lens 1230 (e.g., objective lens), a first dichroic mirror
1240, a second dichroic
mirror 1250, and a second lens 1260 (e.g., condensing lens). As shown, optical
detector
1210, illumination device 1212, and laser 1220 share a coaxial optical path
between first
dichroic mirror 1240 and first lens 1230. Figure 12 also includes an IGU 1270
with a defect
(not shown) being imaged and mitigated. The IGU 1270 has a first lite 1272
(first pane) and
a second lite 1274 (second pane) with an electrochromic device disposed on a
surface 1276 of
the second lite 1274. The defect being mitigated is located on the surface
1276 of the second
lite 1274.
[0120] During the imaging and mitigation operation illustrated in Figure
12, illumination
device 1212 provides collimated illumination light. The illumination light is
reflected at
about 90 degrees from the second dichroic mirror 1250, and then reflected at
about 90
degrees from first dichroic mirror 1240 to first lens 1230 which focuses the
illumination light.
The focused illumination light passes through the first lite 1272 to the
second lite 1274 of the
IGU 1270. Illumination light reflected from the second lite 1274 to the first
dichroic mirror
1240, which is reflected at about 90 degrees to second dichroic mirror 1250.
The light passes
through the second dichroic mirror 1250 to second lens 1260. Second lens 1260
focuses the
reflected light to the optical detector 1210. The optical detector 1210 can
form an image of
the defect based on light reflected from the defect area.
[0121] In Figure 12, the laser 1220 emits light for mitigating the defect.
The light from
laser 1220 passes through the first dichroic mirror 1240, and is reflected at
about 90 degrees
from mirror 1234 to the first lens 1230. The first lens 1230 focuses the
mitigating light to a
focal point. The first dichroic mirror 1240 is specified such that the
wavelength or
wavelengths of light from laser 1220 passes through the first dichroic mirror
1240. The
second dichroic mirror 1250 is specified such that the wavelength or
wavelengths of light
from illumination device 1212 is reflected by the dichroic mirror 1250. First
lens 1230
focuses the collimated light from laser 1220 to a focal point at or near
surface 1276 to
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concentrate the energy of the light to a targeted portion to mitigate the
defect. First lens 1230
also focuses the collimated light from illumination device 1212 to a focal
point on or near to
surface 1276. In this optical system 1200, there is a common axis (coaxial
path) of the laser
and illumination light from the first dichroic mirror 1240 to the minor 1234
and from the
mirror 1234 through the first (focal) lens 1230, and then to the focal point.
[0122] As shown, light from laser 1220 and illumination device 1212 is
collimated and
along a coaxial path to the first lens 1230. Since the light received at the
first lens 1230 is
collimated and coaxial, the first lens 1230 can focus both the mitigating and
imaging light to
an aligned focal point. Also, moving the first lens 1230 along the optical
path axis can
control the location of the focal point of both the laser light and imaging
light. That is, the
position of the first lens 1230 along the coaxial optical path can be adjusted
to finely focus
laser 1220, optical detector 1210, and illumination device 1212. The optical
system 1201 and
other similar optical systems having a coaxial optical path of collimated
light allow the laser
to be aimed at the defect and provide accurate alignment of the detection and
mitigation
processes. In these optical systems, laser 1220, optical detector 1210, and
illumination
device 1212 can be automatically focused with a dynamic autofocus system
disclosed herein.
To illustrate this aspect, Figure 12 also includes a dynamic autofocus system
1000 having a
lens positioning mechanism 1020, a detection mechanism 1030, and a processor
1040 in
communication with lens positioning mechanism 1020 and detection mechanism
1030. Lens
positioning mechanism 1020 is in communication with the first lens 1230 to
move the first
lens 1230 to maintain the focal point at the same distance from the first lens
1230 as the IGU
1270 may flex or otherwise move during the process.
[0123] In the optical systems shown in Figure 11A and 11B, Figure 12, in
Figures 13A-
I, and other disclosed embodiments, the propagated light from the laser and
optical detector
are provided along a common axis from one side of the IGU. This arrangement
allows the
option of including a pivot system for swiveling one or more components of the
optical
system around to image and mitigate defects to reach comers or underneath
spacers (not
shown) at the edges of the IGU. For example, such as pivot system can be used
to swivel or
otherwise rotate the mirror 1234 described with reference to Figures 11A and
11B.
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[0124] PORTABLE DEFECT MITIGATOR SUBSYSTEMS
[0125] Certain embodiments of portable defect mitigators disclosed herein
may include
one or more of the following subsystems: 1) X-Y stage for moving the optical
system with
respect to the window surface to increase the field of view; 2) one or more Z-
stages for
moving the focal point; 3) tether system; 4) a vacuum engagement system for
affixing the
portable defect mitigator to the surface of the window; 5) a dynamic autofocus
system; 6)
imaging and mitigation subsystems which share a common axis from a dichroic
mirror
through the focal lens and onto the window surface, 7) a pivot system for
pivoting the optics
in a portable defect mitigator mounted to the window in order to image and
mitigate defects
at the corners or underneath a spacer of an IGU; 8) a chassis; 9) case-like
structure with a
separate chassis; 10) a tracking stylus; and 11) a beam blocker.
[0126] An example of a portable defect mitigator 1400 with many of the
above-listed
subsystems can be found described below with reference to Figures 13A-I. Other
examples
of the above-listed subsystems can be found throughout the disclosure. For
example, a
dynamic autofocus system is described in a section above. As another example,
imaging and
mitigation subsystems which share a common axis from a dichroic mirror through
the focal
lens and to surface of a window are described above with reference to Figure
11A, Figure
11B, Figure 12, and Figure SC. As another example, a pivot system is described
below with
reference to Figure 11A and Figure 11B. In certain embodiments, the portable
defect
mitigators described with reference to Figures 13A-I and Figure 14 may include
the optical
system described with reference to Figures 11A, 11B, and 12.
[0127] ¨ Chassis
[0128] The chassis is of a compact and low weight design for handheld
operation by the
user. In one example, the chassis structure and its contents weigh about 10
pounds.
Although the chassis structure may be of any shape, the chassis of certain
implementations is
in the general shape of a rectangular box. In some cases, the chassis
structure may be made
of a low weight material such as, for example, carbon-fiber based composite
materials. In
most cases, the chassis is designed as a light-tight enclosure to ensure that
laser light does not
leave the chassis during mitigation for safety concerns. The chassis may
include one or more
handles to facilitate portability. The handles are designed to allow the
operator to affix the
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chassis to the window surface. The chassis has components designed to mate and
engage the
portable defect mitigator to the surface of the window during operation.
[0129] Figure 13A is an isometric drawing a portable defect mitigator 1400
including a
box-shaped chassis 1410, according to an embodiment. In the illustrated
embodiment, the
chassis 1410 is a light tight enclosure. The chassis 1410 is in a general form
of a box having
approximate dimensions of 7.5 inches x 7.5 inches on the face for engaging the
window and 8
inches in width. In other embodiments, the chassis may be of a smaller size.
In the
illustrated example, the chassis 1410 in the process of being affixed to an
IGU 1270 having
two electrochromic lites. The chassis 1410 in the illustration is a carbon-
fiber based design
and the chassis and its contents weigh about 10 lbs.
[0130] The chassis 1410 includes two handles 1420. Each handle 1420 is
attached at two
ends to two flanges connected along opposing edges of a surface 1430 of the
chassis 1410.
The chassis 1410 also includes two ports 1440, 1442 extending from the back
surface 1430.
The first port 1440 may be a vacuum port for attaching a vacuum line. The
other end of the
vacuum line may be connected to a vacuum device. The second port 1442 may be a
power
port for connecting a power line. The power line may be connected to a power
source. The
chassis 1410 also includes a protruding portion having an input port 1450.
[0131] - Separate Case
[0132] In certain embodiments, a portable defect mitigator will include two
main
portions: 1) a first portion with a case-like (e.g., briefcase-like, suitcase-
like, etc.) structure
that holds the electronics, software, and optionally a user interface, and 2)
a separate second
portion with a chassis containing components of the optics system, the dynamic
autofocus
system, stages for the optical components, and devices for affixing the
chassis to the surface
of the window. In some implementations, the laser is in the case-like
structure. In other
implementations, the laser is in the separate chassis. The chassis portion is
separate from the
case-like structure and is typically in a compact and light-weight design that
can be handheld
during operation. The chassis portion is designed to mate and engage to the
surface of the
window to be remedied. While the case-like portion may also be handheld, it is
designed to
contain the heavier and bulkier components of the portable defect mitigator.
This allows the
chassis portion to be lighter, easily maneuverable by the operator, and
capable of being
affixed to the surface of the window during operation.
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[0133] Components within the chassis may be in communication with
components within
the case-like structure through one or more connectors. For example, there may
be a fiber-
optic cable between the laser in the case-like structure and the optics in the
separate chassis to
propagate light from the laser through the optics to mitigate the defect at
the window. As
another example, there may be a vacuum line between a vacuum device in the
case-like
structure and the vacuum system in the chassis to apply a vacuum to the vacuum
system
holding the chassis to the window during defect imaging and mitigation. In yet
another
example, there may be a power line between a power source in the case-like
structure and the
chassis.
[0134] - Tether
[0135] In certain embodiments, the portable defect mitigator may include a
tether system
for added safety. The tether subsystem may include a vacuum device (e.g.,
suction cup) that
is connected to a tether line. The tether line is attached to the portable
defect mitigator, for
example, at the portion of the chassis facing upward. Some examples of devices
that can be
used as tether lines include a cable, a spring-loaded reel, or a reel
counterbalance. The
vacuum device may be attached to a structure located above the defect area
such as, for
example, a wall above the electrochromic window or a portion of the
electrochromic window
itself. The vacuum device can provide an anchor and provides an upward force
to the tether
line that can take some moment off the laser head and/or the engagement system
(e.g., the
vacuum engagement system discussed below) used to affix the portable defect
mitigator to
the window. In addition, the tether system can provide a safety line that can
hold the portable
defect mitigator if the engagement system fails or if the mitigator is dropped
when moving it
from one defect area to another defect area on the window.
[0136] - Vacuum Engagement System
[0137] In certain embodiments, the portable defect mitigator includes a
vacuum
engagement system for affixing the chassis to the surface of the window during
the defect
imaging and mitigation procedure. The vacuum engagement system is designed to
make a
substantially rigid engagement between the window and the portable defect
mitigator.
[0138] Figure 13B is an isometric drawing of the portable defect mitigator
1400 depicted
in Figure 13A. In this illustration, the portion of the portable defect
mitigator 1410 that
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engages the window in shown. This portion includes a vacuum engagement system
1470
with 0-rings for affixing the portable defect mitigator 1400 to a surface of a
window. The
vacuum engagement system 1470 includes a mating base plate 1472 having a
plurality of
three shallow low-profile recessed regions 1474, 1476, 1478 (e.g., recesses)
and a
circumferential groove around each region. In other embodiments, the plurality
of recesses
may have other numbers of recesses (e.g., two or more). Each of the low-
profile regions
1474, 1476, 1478 can from a vacuum seal with the window using 0-rings or other
sealing
member that fit into the circumferential grooves. When mating to the window
surface, each
of the low-profile regions 1474, 1476, 1478 forms a separate shallow vacuum
chamber with
the window. Each one of the low-profile regions 1474, 1476, 1478 is designed
(e.g., with a
large enough area and depth) to create a vacuum chamber sufficient (i.e. with
enough suction
force) to hold the chassis portion onto the surface of the window during
mitigation. Based on
this triple safety design, if any two of the vacuum chambers loses vacuum, the
remaining
vacuum chamber can hold the chassis 1410 engaged with the window. For
additional safety,
each of the vacuum chambers is separately controllable (e.g., by a set of
valves) and isolated,
so that if any one of the vacuum chambers loses vacuum, the other two chambers
do not
similarly lose vacuum and can keep the chassis 1410 engaged with the window.
For
example, the system may have a set of valves. Each valve controls vacuum in a
single
chamber associated with that valve. In some cases, the valves may be
independently
controlled.
[0139] In this illustration, a laser beam 1480 is shown extending from the
surface of the
chassis 1410 through an area separate from the low-profile regions 1474, 1476,
1478. In
some cases, the vacuum engagement system 1470 may also include a feedback
control
system that determines if one or more of the chambers loses vacuum. If one or
more vacuum
chambers loses vacuum, the feedback control system can send a shutoff signal
to the laser,
which may provide additional safety.
[0140] In certain implementations, the portable defect mitigator may employ
a Class 4
laser for defect mitigation. In these cases, there may be a potential risk if
the mitigator
disengages from the window during mitigation that the laser beam directed
outside the light
tight enclosure can potentially cause injury. The triple safety vacuum
engagement system
1470 of Figure 13B and engagement systems of other disclosed embodiments can
help
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ensure that the portable defect mitigator does not disengage from the window
during defect
mitigation.
[0141] In some cases, a tether system describe herein may also be included
to provide
additional safety if the engagement system disengages. In other cases, a low
power
consumption laser may be used, which allows for a non-tethered defect
mitigator. In one of
these cases, the low-profile regions 1474, 1476, 1478 cavities may be welded
to form a
plenum that could store vacuum, enabling the use of a very small pump to pump
out the
plenum and be valved to and then stuck to the window. Although a high velocity
vacuum
may be need to provide the initial suction to the window in a short amount of
time, very little
vacuum is required to maintain the vacuum once affixed to the window. Having a
storage
volume can enable using a vacuum pump on board and could go along with
enabling the use
of a diode or low power consumption laser thus having a non-tethered defect
mitigator.
[0142] - X-Y stage and Z stages position adjustments
[0143] In certain embodiments, the field of view of the optical detector
(e.g., camera) in a
portable defect mitigator may be a relatively small area (e.g., an area of
about 7 mm x 7 mm).
To widen the field of view of the optical detector and also to be able to move
the laser over a
larger area, the portable defect mitigator may include an X-Y stage and/or or
Z-stage that can
move relative to the window onto which the portable defect mitigator is
mounted. The X-Y
stage is associated with movement in a plane that is parallel to the surface
of the window.
The Z-stage is associated with movement normal to the plane parallel to the
surface of the
window.
[0144] The optical system or components (e.g., laser and/or optical
detector) of the
optical system can be mounted to an X-Y stage to widen the field of view of
both the optical
detector and the laser. By using such X-Y stage, a portable defect mitigator
affixed to the
window can have a wide imaging and mitigating area. In some embodiments, an X-
Y stage
may be able to move the optical system over an area of the window surface in
the range of
between 7 inches x 7 inches. The X-Y stage can be mounted to a Z-stage. The Z-
stage can
provide movement toward and away from the window surface. In some embodiments,
a
portable defect mitigator includes two Z-stages: 1) a first stage for
adjusting the optics to
roughly locate the focal point at a surface of IGU; and 2) a second Z-stage
for focusing the
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optics. The first stage may have a wider range of movement (e.g., 1 inch, 1.5
inches, 2
inches, etc.) than the second stage.
[0145] Figure 13C is an isometric drawing of components of the portable
defect
mitigator 1400 depicted in Figures 13A and 13B. In this illustrated example,
the side and
back panels of the chassis 1410 have been removed to view the components
within. These
components include an optical system 1490 mounted to an X-Y stage 1500. The X-
Y stage is
connected to a first Z-stage 1510. The Z-stage includes X-axis, Y-axis, and Z-
axis at the
corner. The Z-stage 1510 has cutouts that slidably connect to three linear
screws 1535
affixed at one end to the base plate 1472 of the chassis 1410. This connection
allows the
stage mounting plate 1510 to move in the Z direction with respect to the base
plate 1472 and
the window, which will be described in more detail below in reference to
Figures 13D and
13E. The X-Y stage 1500 can move in the X-direction and Y-direction relative
to the first Z-
stage 1510 and the first Z-stage 1510 can move in the Z-direction relative to
the base plate
1472. The potable defect mitigator 1400 also includes a second Z-stage that is
a component
of a dynamic autofocus system. In the illustrated example, the X-direction
refers to both the
positive and negative direction in an axis parallel to the X-axis, the Y-
direction refers to both
the positive and negative direction in an axis parallel to the Y-axis, and the
Z-direction refers
to both the positive and negative direction in an axis parallel to the Z-axis.
[0146] Figures 13D and 13E are isometric drawings of components of the
portable defect
mitigator 1400 depicted in Figures 13A-C. In Figures 13D and 13E, the chassis
1410 and
the optical system 1490 have been removed to view the X-Y stage 1500 and other
components of the portable defect mitigator 1400. The portable defect
mitigator includes a
mechanism (e.g., a high speed motor) that controls the movement of the X-Y
stage 1500 and
the mounted optical system 1490 in the X-direction and in the Y-direction
relative to the
surface of the window.
[0147] The X-Y stage 1500 includes two sliding platforms 1501(a) and
1501(b). Sliding
platform 1501(a) can slide in the X-direction within a set of rails. Sliding
platform 1501(b)
slides in the Y-direction within a set of rails. The X-Y stage 1500 includes
two mechanisms
for rotating threaded rods. The first mechanism rotates a first threaded rod
to engage and
translate sliding platform 1501(a) in the X-direction. The second mechanism
rotates a second
threaded rod to engage and translate sliding platform 1501(b) in the Y-
direction. The first
and second mechanisms controlling the threaded rods can be manually controlled
by the
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operator or automatically controlled by an actuator that receives control
signals from a
processor of the portable defect mitigator 1400. For example, these mechanisms
can be a
linear motor, manual linear actuator, etc. In the illustrated embodiment, the
field of vision of
the optical detector in the optical system 1490 is about 7 mm x 7 mm at the
surface of the
electrochromic device. By employing the X-Y stage 1500, the field of vision of
the optical
detector and laser is increased to 22 mm x 22mm.
[0148] The portable defect mitigator 1400 also includes a thickness
adjustment knob
1530, a glass thickness indicator 1532, a belt and gear assembly 1534, and
three linear screws
1535, and two posts 1537 (shown in Figure 13E). These components are used to
adjust the
Z-direction coordinate of the optical system 1490 to calibrate the optical
system 1490
according to the thickness of the window being mitigated. In one case, the Z-
direction
coordinate can be adjusted to locate the focal point of the laser at a surface
of the
electrochromic device of an electrochromic window in an IGU before the window
flexes.
The Z-direction coordinate is adjusted by rotating the thickness adjustment
knob 1530. In
one case, the thickness adjustment knob 1530 may be rotated to align a marker
on the
thickness adjustment knob 1530 to an appropriate indicator on the glass
thickness indicator
1532. The glass thickness indicator 1532 may have a series of indicators that
designate
different thicknesses.
[0149] This adjustment may be based on one or more window parameters such
as, for
example, the thickness of the insulated glass unit, the thickness of the
window unit, the
thickness of the spacer, the thickness of each pane or lite, etc. In one
embodiment, the
adjustment may be based on the standard thickness of the window (or IGU)
and/or the
thickness between the surface of the engaged lite to the surface of the
electrochromic device
having the defect. The adjustment can be used to calibrate the starting
position of the focal
point of the laser. For example, if the defect is located on an electrochromic
device of an
outer lite (non-engaged lite) of an IGU having multiple Ines, the thickness
adjustment knob
1530 can be used to calibrate the starting position of the focal point of the
laser at a surface of
the electrochromic device of the outer lite. If the defect is located on an
electrochromic
device of the engaged lite, the thickness adjustment knob 1530 can be used to
calibrate the
starting position of the focal point at the electrochromic device of the outer
lite. This
adjustment is generally made before initiating the defect imaging and
mitigation process.
Once this process starts, a dynamic autofocus system 1000 shown with respect
to Figure 9
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can be used to make fine adjustments to the Z-position of the focal point to
accommodate for
flexing or other movement of the window. In some cases, an LED or other type
of indicator
can be used in concert with the dynamic autofocus system or other means of
measuring glass
thickness described herein to precisely adjust the Z-position either manually
or automatically
where the linear screws 1535 can be turned by electric motors.
[0150] The belt and gear assembly 1534 includes a series of gears engaged
to move by at
least one belt. One of the gears is a master gear affixed to an end of a
linear screw 1535
having the glass thickness adjustment knob 1530 at the opposing end. Rotating
the glass
thickness adjustment knob 1530 rotates the master gear at the end of the
linear screw 1535,
which moves the belt, which rotates the other gears including slave gears
attached to the other
linear screws 1535. Thus, rotating the glass thickness adjustment knob 1530
effects
equivalent and simultaneous rotation of all three linear screws 1535. The
linear screws 1535
include a threaded portion at the end proximal the mounting plate 1510. The
threaded portion
of the linear screws 1535 movably engages a linear screw nut 1536 affixed to
the mounting
plate 1510. As the linear screws 1535 are rotated using the glass thickness
adjustment knob
1530, the mounting plate 1510 translates in the Z-direction guided by the two
posts 1537 with
linear bearings to adjust the Z-position of the mounting plate 1510. The
portable defect
mitigator 1400 also includes a guide shaft 1537 between the base plate 1472
and the stage
mounting plate 1510. The portable defect mitigator 1400 also includes an
optional belt
tensioner 1538. The belt tensioner 1538 allows an idle gear to be moved on a
slide to tighten
the belt.
[0151] In one embodiment, the portable defect mitigator 1400 may include a
system
where the linear screws 1535 can be turned by electric motors. For example, a
triangulation
sensor may provide feedback to indicate when to stop moving the linear screws
1535.
[0152] The portable defect mitigator 1400 depicted in Figures 13A-E also
includes an
optical system 1490 with a similar arrangement to that of the optical system
1200 depicted in
Figure 11. Figures 13F, 13G, 13H are isometric drawings of components of
optical system
1490. Optical system 1490 includes a laser input 1491 and a laser optics block
1492 in
communication with laser input 1491. Laser input 1491 includes port 1450
connected to
optical fiber 1460. Laser optics block 1492 is in communication with a main
optics block
1493. The optical system 1490 also includes an optical detector 1494 (e.g.,
camera), a vision
optics block 1495, and a dynamic autofocus system having a triangulation
sensor 1132. The
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autofocus system is similar to the dynamic autofocus system 1000 describe with
reference to
Figure 9 and includes triangulation sensor 1132.
[0153] In the optical system 1490, there is a coaxial optical path between
the laser input
1491 and the detection optics 1494 to align the detection and mitigation
processes. In
addition, collimated light is provided from the laser and optical detector
along the coaxial
path to the focusing lens. This arrangement allows the dynamic autofocus
system to adjust
the focusing lens to dynamically focus both the laser and optical detector to
the same focal
point 1480 as the window may flex during the imaging and mitigation process.
[0154] ¨ Pivot System
[0155] In some cases, defects can be concentrated near the edges of an
electrochromic
window in an IGU. This can sometimes be the result of scribing processes
performed on a
fabricated window. While the spacer at the edges of the IGU may partially
obscure these
edge defects, the penumbra or halo around the defects may well extend into the
viewable area
inside the footprint between the spacers.
[0156] Embodiments disclosed herein include a portable defect mitigator
that can
mitigate defects underneath the spacer and at the corners. These portable
defect mitigators
may be particularly effective in mitigating defects in a cantilevered spacer
design, which
allows greater access by defect mitigation optics to reach underneath the
spacer. An example
of a cantilevered spacer design and other spacer designs can be found in
Patent Application
Serial No. 61/421,154, filed on December 28, 2010, entitled "Improved
Separators for
Insulated Glass Units," which is hereby incorporated by reference in its
entirety.
[0157] The optical systems shown in Figures 11A-11B, in Figure 12, and in
Figures
13A-H, and in other disclosed embodiments are particularly adaptable to pivot
the focal point
of the laser to mitigate under the spacer and at the corner. In these systems,
the propagated
light from the laser 1220 and optical detector 1210 are provided along a
common axis path
from one side of the IGU. This arrangement allows the option of including a
pivot system for
pivoting the final optics path of the laser and vision together to image and
mitigate defects to
reach corners or underneath spacers at the edges of an IGU. Basically, the
pivot system
allows for pivoting around the laser dot on the dichroic mirror surface in any
direction. In
one embodiment, a pivot system includes a pivot mechanism (e.g., motor) that
can control the
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rotation of the mirror 1234 and the first lens 1230 described with respect to
Figures 11A and
11B. Another example of a pivot system includes a mechanism for pivoting the
dichroic
mirror (e.g., dichroic mirror 1240) and the focal lens (e.g., lens 1230) as a
unit along an axis
in a plane parallel to a plane approximating the surface of the electrochromic
device. For
example, the pivot system could pivot the X-Y stage 1500 about one or more
axes lying in
the X-Y plane, which is parallel to the plane approximating the surface of the
window.
[0158] In embodiments having a pivot system, the laser beam is pivoted at
an angle,
which could reflect off a back plate and out of the light tight enclosure of
the chassis. In these
embodiments, the portable mitigator may include a light blocking material
(e.g., hat, sleeve,
etc.) placed skirting out from the side of the chassis to extend the light
tight area and provide
side protection from the laser beam.
[0159] - Tracking Stylus
[0160] In certain embodiments, a portable defect mitigator will include a
tracking stylus
to set the coordinates of the focal point for mitigating the defect. For
example, a user can
place the tracking stylus at or near one or more defects of an electrochromic
window in a
tinted state to define the coordinates of the one or more defects. The
defect(s) coordinates
can be communicated to a processor which determines a set of instructions for
automatically
mitigating the one or more defects. These instructions may include information
for operating
the laser and for moving the laser to the coordinates. These instructions may
be
communicated to the motor controlling the X-Y stage, the pivot system, and/or
other system
for locating the focal point of the laser at the coordinates of the defects.
The set of
instructions is also communicated to the laser to control the timing and
energy of the
emissions from the laser.
[0161] - Beam Blocker
[0162] In certain embodiments, a portable defect mitigator may include a
beam blocker.
The beam blocker is affixed to an outer surface of the IGU adjacent the defect
being
mitigated. The outer surface is opposite the surface of the IGU to which the
portable defect
mitigator is attached. The beam blocker reflects or blocks the laser light
from exiting through
the outer surface to address safety concerns. The beam blocker may also be
used as a
detection mechanism 1030 to measure the distance to the surfaces within the
IGU. In this
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case, other detection methods may be employed such as ultrasonic, capacitive,
or other laser
measurement techniques. Using a beam blocker may be a less expensive
alternative to using
an internal triangulation sensor.
[0163] Exemplary method of defect imaging and mitigation
[0164] Figure 14 is a flowchart of a method of defect imaging and
mitigation, according
to embodiments. At step 1715, a window is identified for defect remediation.
In some cases,
this may involve a human detecting a halo or other perceptible defect in a
window in the
tinted state. The human may visually inspect or use a magnification device
(e.g., microscope)
to determine whether there is a defect. In other cases, the defect may be
determined by an
automated detection system that uses a light detector to measure light
transmitted through the
window in the tinted state to identify the window for remediation. In yet
other cases, the
defect may be determined using thermal imaging such as, for example, lock-in
thermography.
[0165] At step 1720, a portable defect mitigator is mounted to the surface
of the window
near the region where the defect was observed. For example, the chassis
portion 1410 of the
portable defect mitigator 1440 can be affixed as shown in Figure 13A to a
surface of an
electrochromic window. The portable defect mitigator can be mounted to the
surface using
various attachment methods. For example, the portable defect mitigator may be
mounted to
the surface using a vacuum engagement system such as, for example, triple
safety vacuum
engagement system 1470 described in reference to Figure 13B that forms three
isolated
vacuum chambers with the surface, each capable of holding the chassis 1410 to
the window.
As another example, the portable defect mitigator may be mounted to the
surface using a
mechanical clamp.
[0166] At step 1725, the imaging system of the portable defect mitigator is
brought into
focus with the surface of the electrochromic device. A sharp image of the
surface is
generated at the optical detector (e.g., camera) when the focal lens and the
surface of the
electrochromic device are separated by the focal length of the lens. Moving
the lens to the
proper separation can be accomplished either manually or automatically. In one
example, the
portable defect mitigator may have an autofocus device that can move the lens
to the proper
focal length. In another example, the operator may move the lens manually to
focus on the
surface. In yet another example, an operator using a portable defect mitigator
1400 depicted
in Figures 13A-H may rotate a thickness adjustment knob 1530 to move the focal
point of
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the laser near or at the surface of the electrochromic device based on a
standard thickness of
the electrochromic window or IGU. In some cases, this is an approximation and
only roughly
places the focal point at the surface. This is used when remedying defects in
an IGU. The
rough approximation is a starting point to ensure that the focal point is at
the correct surface
of an IGU. The operator or automated system can finely tune the focus to the
plane at the
surface once the focal point is close to the surface. This helps to ensure
that the defect
mitigator is focused on the correct electrochromic device where there may be
more than a
single electrochromic device, for example, in an IGU.
[0167] At step 1730, the optical system of the portable defect mitigator
optionally targets
the defect area within the field of view of the image and mitigation system.
In some cases,
the optical system may be moved in the x-direction and the y-direction to
center or otherwise
locate field of view of the optical detector and laser proximal the defect.
For example, the
portable defect mitigator 1400 depicted in Figures 13A-H includes an X-Y stage
for moving
the optical system in the X-direction and the Y-direction. The X-Y stage can
be moved so
that the defect is at or near the center of the field of view. In some
embodiments, step 1730 is
performed prior to step 1725.
[0168] Once the image system is properly focused on a field of view of the
electrochromic device surface, the putative defects within the field of view
are identified
(step 1735). A processor (e.g., microprocessor) in the portable defect
mitigator may process
code or other logic having instructions to identify the putative defects
within the field of view
based on the intensity of light detected as passing through particular regions
in the field of
view. The logic may also include instructions to identify the putative defects
by location and
intensity or other characterizing parameters (e.g., wavelength, etc.) of the
light. The
processor may also process code having instructions that define a scribe
circle or other scribe
pattern around the putative defect. Alternatively, the user can specify a
scribe circle or other
scribe pattern using a user interface. Some examples of variations on a simple
circular scribe
pattern can be found in U.S. Patent Serial No. 61/649,184, filed on May 18,
2012, entitled
"CIRCUMSCRIBING DEFECTS IN OPTICAL DEVICES," which is hereby incorporated
by reference in its entirety. In one implementation, the user can select any
one or more of
these putative defects to be mitigated using a user interface. When the user
selects such
defects, the X-Y stage may align the system to the defects by putting them in
the center of the
field of vision. At that location, the scribe laser is also aligned with the
defect.
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[0169] Once the defect for mitigation and the associated scribe diameter
have been
determined, the portable defect mitigator can execute the laser scribe to
mitigate the defect.
At step 1740, the portable defect mitigator mitigates the selected defect
based on the selected
scribe diameter. In some cases, an X-Y stage may be used to translate the
focal point along
the scribe pattern within the scribe diameter. In some cases, a dynamic
autofocus system can
be used to adjust the z-position of the focal point during scribe. For
example, the dynamic
autofocus system 1000 depicted in Figure 11 can be used to determine any
movement of the
surface of the electrochromic device during mitigation. If the dynamic
autofocus system
1000 determines that the surface has moved, typically due to window flexing,
the system
1000 can adjust the lens to place the focal point back at the surface.
[0170] After the scribe has taken place, a confirmatory image may be
captured to ensure
that the defect has been appropriately mitigated, at step 1745. In this
regard, the gradient of
light intensity can be measured in the X or Y direction. A very steep gradient
suggests that
the remediation was effective. An un-remedied halo defect has a very gradual
or diffuse
variation in light intensity. After the remediation is completed at a
particular location on the
window, the defect mitigator may be disengaged by breaking vacuum and either
put away or
move to a different portion of the window, or even a different window in the
vicinity, and
used to remedy one or more additional defects.
[0171] In one embodiment, a pivot system is employed. The pivot system is
designed to
allow the detection and/or scribe optics to pivot such that the scribe laser
can strike the
surface of the electrochromic device at an angle deviating from the normal
(i.e., an angle
other than 900 from the plane of the device). Thus, the pivot system can be
used to allow the
optical system to be able to view and/or mitigate a defect under a spacer or a
corner of an
IOU.
[0172] The portable defect mitigator does not move as a whole during a
typical defect
identification and mitigation procedure. However, there may be vibration or
another external
force on the structure with the defect being mitigated that moves the
structure with the
portable defect mitigator attached during an identification and mitigation
procedure. For
example, there may be vibration from the wall or other building component to
which the rail
system in Figure 5A is attached. In certain embodiments, active and/or passive
vibration
isolation can be used to isolate the portable defect mitigator from these
forces. For example,
components having materials and geometry tuned to dampen the predicted or
measured
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vibrations can be used to passively isolate the portable defect mitigator from
the vibrations.
In an example using active stabilization, a gyroscope or pendulum may be used
to actively
stabilize the portable defect mitigator from the vibrations.
[0173] In one embodiment, the portable defect mitigator may include an
optical system
having a laser mitigating the defect, an optical detector (e.g., camera), and
an illumination
device that do not have the same co-axial optical path. in this embodiment,
other
mechanisms can be used to pair the focus of the laser, illumination device,
and optical
detector. By separating the optical path of one or more of these devices, the
optics in these
devices can be individualized optimized. In addition, by separating the
optical path, there can
be automated and independent movement of each device for focusing purposes.
This can
enable the individual design of different focusing characteristics, such as
focal depth and area
of focus, for each of the devices.
[0174] In one embodiment, a dynamic autofocus system may determine the
distances to
the deformed surfaces of an IGU. Based on these distances, the dynamic
autofocus system
may be able to determine the optical properties of the deformed surfaces of
the IGU. The
dynamic autofocus system may accommodate for these changes by adjusting the
laser
parameters used for mitigation. For example, the dynamic autofocus system may
adjust the
focal distance needed for the laser based on the optical properties of the
deformed IGU
surfaces.
[0175] One of ordinary skill in the art will appreciate that various
combinations of the
above embodiments are contemplated in this description. For example, apparatus
400 and/or
500 may include wireless communication components. In another example,
apparatus 600
may travel on a rail system such as described in relation to Figure 5B, even
though apparatus
600 is smaller than the window pane upon which remediation is intended. In
another
example, apparatus 500 may be on a cart or table rather than a tripod. In yet
another
example, the identification mechanism and the mitigation mechanism may be
apart from one
another, not adjoining as depicted in the figures. In another example, the
identification
mechanism and the mitigation mechanism may have independent movement
mechanisms. In
yet another example, base 605 of apparatus 600 (see Figure 7) may have a
mechanism for
rotating the identification mechanism and/or the mitigation mechanism. In yet
another
example, X-Y stages may have various configurations, methods of driving linear
or rotation
actuators and the like.
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[0176] Although the foregoing has been described in some detail to
facilitate
understanding, the described embodiments are to be considered illustrative and
not limiting.
It will be apparent to one of ordinary skill in the art that certain changes
and modifications
can be practiced within the scope of the appended claims.
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