Note: Descriptions are shown in the official language in which they were submitted.
SYSTEM FOR THERMALLY CONTROLLING AN ELECTRONIC
DISPLAY WITH REDUCED NOISE EMISSIONS
Inventors: William Dunn, Tim Hubbard, and Ware Bedell
Technical Field
(0001] Exemplary embodiments generally relate to cooling systems and in
particular
to cooling systems for electronic displays.
Background of the An
[0002] Improvements to electronic displays now allow them to be used in
outdoor
environments for informational, advertising, or entertainment purposes. While
.displays
of the past were primarily designed for operation near room temperature, it is
now
desirable to have displays which are capable of withstanding large surrounding
environmental temperature variations. For example, some displays are capable
of
operating at temperatures as low as -22F and as high as 113 F or higher. When
surrounding temperatures rise, the cooling of the internal display components
can
become even more difficult.
[0003] Additionally, modern displays have become extremely bright, with some
backlights producing 1,000-2,000 nits or more. Sometimes, these illumination
levels
are necessary because the display is being used outdoors, or in other
relatively bright
areas where the display illumination must compete with other ambient light. In
order to
produce this level of brightness, illumination devices and electronic displays
may
produce a relatively large amount of heat.
[0004] Still further, in some situations radiative heat transfer from the sun
through a
front display surface can also become a source of heat. In some locations 800-
1400
Watts/m2 or more through such a front display surface is common. Furthermore,
the
market is demanding larger screen sizes for displays. With increased
electronic display
screen size and corresponding front display surfaces, more heat will be
generated and
more heat will be transmitted into the displays.
1
STL=TCNUPCT-CDA
CA 2809019 2017-11-28
[0005] Exemplary modern displays have found some effective means for cooling
the
displays including circulating a closed loop of gas around the display and
drawing
ambient gas through the display so that the closed loop of gas may be cooled
(as well
as portions of the electronic display). Various thermal communications have
been
discovered which can transfer heat away from the sensitive electronic
components and
out of the display. Heat exchangers were found to produce an excellent means
for
transferring heat between the closed loop of gas and the ambient gas. However,
previous designs for moving the gas through the display have been found to
generate
an undesirable amount of noise emission from the display as well as thermal
gradients
where portions of the display were cooled but others remained warm.
[0006] When using LCD displays, it was found that backlights were often a
source of
heat and it was desirable to move gas across the rear surface of the backlight
in order
to cool it. While desirable, it was thought that the front surface of the
backlight could
not be cooled for fear that the backlight cavity would become contaminated
with dust,
dirt, or other particulate.
Summary of the Exemplary Embodiments
[0007] In an aspect, there is provided an assembly for cooling an electronic
image
assembly within a housing having an inlet aperture for ambient gas, exit
aperture for
ambient gas, and internal cavity for circulating gas. The assembly comprises a
first
portion of a heat exchanger which accepts ambient gas from the inlet aperture.
A
second portion of a heat exchanger accepts ambient gas from the first portion.
A
channel is placed behind the electronic image assembly and in gaseous
communication
with the inlet and exit apertures. A first fan is positioned between the first
and second
portions which forces ambient gas through the first portion, second portion,
and the
channel. A second fan forces circulating gas through the internal cavity and
at least
one of the heat exchanger portions.
[0008] In another aspect, there is provided an electronic display assembly
comprising
a housing having an inlet aperture and exit aperture for ambient gas. An
electronic
image assembly is within the housing. A transparent front plate is in front of
the
electronic image assembly, and the space between the transparent front plate
and the
electronic image assembly defines a front channel. A rear plate is placed
behind the
2
STL-TCWPCT-CDA
CA 2809019 2017-11-28
electronic image assembly, and the space between the rear plate and the
electronic
image assembly defines a rear channel. A heat
exchanger is in gaseous
communication with the front channel. The heat exchanger comprises two
portions,
each portion having first and second gas pathways, where the first gas
pathways are in
gaseous communication with the inlet and exit apertures and the second gas
pathways
are in gaseous communication with the front channel. An ambient gas fan
assembly is
placed between the two portions of the heat exchanger to force ambient gas
through
the first gas pathways and through the rear channel; and a circulating gas fan
assembly
is positioned to force circulating gas through the front channel and the
second gas
pathways.
[0009] In another aspect, there is provided a thermally-controlled liquid
crystal display
(LCD) assembly comprising a housing having an inlet aperture and exit aperture
for
ambient gas. A LED backlight has a rear surface and placed within the housing.
A
liquid crystal display (LCD) has a front surface and placed in front of the
LED backlight
and within the housing. A transparent front plate is in front of the LCD, and
the space
between the transparent front plate and the LCD defines a front channel. A
rear plate
is placed behind the rear surface of the LED backlight. A plurality of ribs is
placed
between the rear plate and LED backlight, and the space between the rear
plate, LED
backlight, and ribs defines a plurality of rear channels. A heat exchanger has
a first gas
pathway in gaseous communication with the front channel, and a second gas
pathway
is in gaseous communication with the inlet and exit apertures. An ambient .gas
fan
assembly is placed within the heat exchanger to force ambient gas into the
inlet
aperture, through the second gas pathway and the rear channels, and out of the
exit
aperture. A circulating gas fan assembly is positioned to force circulating
gas through
the front channel and the first gas pathways.
[0010] Exemplary embodiments may use a combination of circulating gas and
ambient gas in order to adequately cool an electronic display. Circulating gas
may be
used to remove heat from the front of the image assembly. Circulating gas may
also be
used to remove heat from internal electronic assemblies, When using a LCD as
the
electronic image assembly, circulating gas may also be used to remove heat
from the
backlight cavity of the LCD. Because the gas is only circulating within the
display, it can
remain free of particulate and contaminates and will not harm the display.
3
STL-7CN/PCT-CDA
CA 2809019 2017-11-28
[0011] Ambient gas may be ingested into the display in order to cool the
circulating
gas. The ambient gas and the circulating gas may be drawn through a heat
exchanger
which will allow the heat to transfer from the circulating gas to the ambient
gas,
preferably without letting the ambient and circulating gases mix with one
another. An
exemplary embodiment would use a cross-flow heat exchanger. An additional flow
of
ambient gas can be drawn across the rear surface of the image assembly to
remove
heat from the rear portion of the image assembly. When using a LCD as the
electronic
image assembly, this additional flow of ambient gas can be used to remove heat
from
the rear portion of the backlight for the LCD.
[0012] In order to reduce noise emissions, the fans which drive the ambient
and/or
circulating gas through the heat exchanger may be placed within the heat
exchanger (or
between two separate heat exchangers), which can then act as a muffler and,
reduce
the noise emitted by the fans. Further, if using the additional ambient gas
pathway
behind the electronic image assembly, a manifold may be used to collect the
ambient
gas along an edge of the display and distribute this into a number of smaller
flows. The
.fans for driving this additional ambient gas pathway can be placed within the
manifold in
order to reduce the noise emitted by the fans and provide an even distribution
of
ambient gas across the display. In an exemplary embodiment, a single fan
assembly
can be used to drive the ambient gas through both the heat exchanger(s) and
behind
the electronic image assembly.
[0013] It has been found that ingesting ambient gas from the top or bottom
edge of
the display is preferable as these edges are not typically observable to the
viewer.
However, when ingesting ambient gas from the top or bottom of a portrait-
oriented
display, it has been found that as the cool ambient gas travels across the
rear portion of
the electronic image assembly and accepts heat it increases in temperature.
Once the
cooling air reaches the opposite edge (either top or bottom), it may have
increased in
temperature substantially and may no longer provide adequate cooling to the
opposing
portion of the display. Thus, the manifolds herein allow for cool ambient air
to
adequately cool the entire electronic image assembly in an even manner and
reduce
any 'hot spots within the electronic image assembly.
4
STLTCN/PCT-CDA
CA 2809019 2017-11-28
[0014] The foregoing and other features and advantages will be apparent from
the
following more detailed description of the particular embodiments of the
invention, as
illustrated in the accompanying drawings.
Brief Description of the Drawinos
[0015] A better understanding of an exemplary embodiment will be obtained from
a
reading of the following detailed description and the accompanying drawings
wherein
identical reference characters refer to identical parts and in which:
[0016] FIGURE 1A provides a front perspective view of an exemplary embodiment
of
the electronic display.
[0017] FIGURE 1B provides a rear perspective view of an exemplary embodiment
of
the electronic display.
[0018] FIGURE 2 provides a rear perspective view similar to that shown in
Figure 1B
where the rear cover has been removed.
[0019] FIGURE 3 provides a perspective sectional view along the A-A section
line
shown in Figure 1B,
[0020] FIGURE 4 provides a perspective sectional view along the BB section
line
shown in Figure 1B,
[0021] FIGURE 5 provides a perspective sectional view of insert C shown in
Figure 4.
[0022] FIGURE 6 provides a perspective sectional view of one embodiment of the
cross through plate.
[0023] FIGURE 7 provides an exploded perspective view of one embodiment of the
heat exchanger.
[0024] FIGURE 8 provides a perspective sectional view of another embodiment
which
uses a flow of circulating gas through the backlight cavity of a liquid
crystal display
(LCD).
FIGURE 9 provides a perspective sectional view of an exemplary embodiment
which
uses a flow of circulating gas through the backlight cavity in addition to the
flow of
circulating gas betWeen the LCD and front plate.
STL=TCN/PCT=CDA
CA 2809019 2017-11-28
[0025] FIGURE 10 provides a rear perspective view of an embodiment using .a
single
fan assembly to control the flow of ambient gas, the embodiment shown with the
rear
cover removed.
[0026] FIGURE 11A provides a perspective sectional view of the embodiment from
Figure 10 based on section line 11A-11A shown in Figure 10.
[0027] FIGURE 11B provides a perspective sectional view of insert B from
Figure
11A.
Detailed Description
[0028] The invention is described more fully hereinafter with reference to the
accompanying drawings, in which exemplary embodiments of the invention are
shown.
This invention may, however, be embodied in many different forms and should
not be
construed as limited to the exemplary embodiments set forth herein. Rather,
these
embodiments are provided so that this disclosure will be thorough and
complete, and
will fully convey the scope of the invention to those skilled in the art. In
the drawings,
the size and relative sizes of layers and regions may be exaggerated for
clarity.
[0029] It will be understood that when an element or layer is referred to as
being "on"
another element or layer, the element or layer can be directly on another
element or
layer or intervening elements or layers. In contrast, when an element is
referred to as
being "directly on" another element or layer, there are no intervening
elements or layers
present. Like numbers refer to like elements throughout. As used herein, the
term
"and/or" includes any and all combinations of one or more of the associated
listed
items.
[0030] It will be understood that, although the terms first, second, third,
etc., may be
used herein to describe various elements, components, regions, layers and/or
sections,
these elements, components, regions, layers and/or sections should not be
limited by
these terms. These terms are only used to distinguish one element, component,
region,
layer or section from another region, layer or section, Thus, a first element,
component,
region, layer or section discussed below could be termed a second element,
component, region, layer or section without departing from the teachings of
the present
invention.
6
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
[0031] Spatially relative terms, such as "lower", "upper" and the like, may be
used
herein for ease of description to describe the relationship of one element or
feature to
another element(s) or feature(s) as illustrated in the figures. It will be
understood that
the spatially relative terms are intended to encompass different orientations
of the
device in use or operation, in addition to the orientation depicted in the
figures. For
example, if the device in the figures is turned over, elements described as
"lower"
relative to other elements or features would then be oriented "upper" relative
the other
elements or features. Thus, the exemplary term "lower" can encompass both an
orientation of above and below. The device may be otherwise oriented (rotated
90
degrees or at other orientations) and the spatially relative descriptors used
herein
interpreted accordingly.
[0032] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of the invention. As used
herein,
the singular forms "a", "an" and "the" are intended to include the plural
forms as well,
unless the context clearly indicates otherwise. It will be further understood
that the
terms "comprises" and/or "comprising," when used in this specification,
specify the
presence of stated features, integers, steps, operations, elements, and/ or
components,
but do not preclude the presence or addition of one or more other features,
integers,
steps, operations, elements, components, and/or groups thereof.
[0033] Embodiments of the invention are described herein with reference to
cross-
section illustrations that are schematic illustrations of idealized
embodiments (and
intermediate structures) of the invention. As such, variations from the shapes
of the
illustrations as a result, for example, of manufacturing techniques and/or
tolerances, are
to be expected. Thus, embodiments of the invention should not be construed as
limited
to the particular shapes of regions illustrated herein but are to include
deviations in
shapes that result, for example, from manufacturing.
[0034] For example, an implanted region illustrated as a rectangle will,
typically, have
rounded or curved features and/or a gradient of implant concentration at its
edges
rather than a binary change from implanted to non-implanted region. Likewise,
a buried
region formed by implantation may result in some implantation in the region
between
the buried region and the surface through which the implantation takes place.
Thus, the
regions illustrated in the figures are schematic in nature and their shapes
are riot
7
STL-TCN/PCT-CIDA
CA 2809019 2017-11-28
intended to illustrate the actual shape of a region of a device and are not
intended to
limit the scope of the invention_
[0035] Unless otherwise defined, all terms (including technical and scientific
terms)
used herein have the same meaning as commonly understood by one of ordinary
skill
in the art to which this invention belongs. It will be further understood that
terms, such
as those defined in commonly used dictionaries, should be interpreted as
having a
meaning that is consistent with their meaning in the context of the relevant
art and will
not be interpreted in an idealized or overly formal sense unless expressly so
defined
herein.
[0038] FIGURE 1A provides a front perspective view of an exemplary embodiment
of
the electronic display 100. A transparent front plate 10 is placed on the
front portion of
the display to protect the internal components and allow the images produced
by the
display 100 to be seen. Some embodiments may use glass as the transparent
front
plate 10. Exemplary embodiments may use two pieces of glass laminated with
index-
matching optical adhesive. Some front plates 10 may provide other utility such
as anti-
reflection or polarizing functions. An inlet aperture 24 and exit aperture 25
may be
provided in the housing so that the display 100 can accept ambient gas for
cooling the
display 100.
[0037] FIGURE
113 provides a rear perspective view of an exemplary embodiment
of the electronic display 100. A rear cover 15 may be used to provide access
to the
internal components of the display 100.
[0038] FIGURE 2 provides a rear perspective view similar to that shown in
Figure 1B
where the rear cover 15 has been removed. Ambient gas 200 may be ingested into
the
display through the inlet aperture 24 and pass through a heat exchanger 45 and
exit the
display through the exit aperture 25. The ambient gas 200 may be drawn into
the
display and forced through the heat exchanger 45 using heat exchanger fan
assembly
46. An exemplary placement for the heat exchanger fan assembly 46 is discussed
further below, but in many embodiments the fan assembly 46 can be placed near
the
inlet aperture 24 and/or exit aperture 25 and may or may not be placed within
the heat
exchanger 45 (as shown in Figure 2).
[0039] Optionally, ambient gas 210 may also be ingested into the display
through inlet
aperture 24. Ambient gas 210 may then be directed through a first manifold 30
which
8
STL-TCN/FCT-CDA
CA 2809019 2017-11-28
travels along the edge of the display. The first manifold 30 accepts the
single larger
inlet flow of ambient gas 210 and distributes it into a plurality of smaller
flows across the
display. A second manifold 35 may be placed along the opposite edge of the
display as
the first manifold 30. The second manifold 35 accepts the plurality of smaller
flows and
combines them into a single flow and exhausts it out of the exit aperture 25.
In this
embodiment, a manifold fan assembly 211 is used to draw the ambient gas 210
into the
inlet aperture 24 and force the ambient gas 210 across the display. For this
particular
embodiment, the manifold fan assembly 211 is placed within the first manifold
30 and is
used to draw the ambient gas 210 into the display as well as distribute the
single flow
into a plurality of smaller flows. This is not required however, as some
embodiments
may place the manifold fan assembly 211 in the second manifold 35, or within
both the
first and second manifolds 30 and 35.
[0040) While both flows of ambient gas may be used in an exemplary embodiment,
there is no requirement that they are both used. Some embodiments may use only
ambient gas 200 or ambient gas 210. Also, if using both flows of ambient gas
200 and
ambient gas 210 there is no requirement that they share the same inlet and
exit
apertures. Thus, there may be separate inlet and exit apertures for the two
flows of
ambient gas.
[0041] FIGURE 3 provides a perspective sectional view along the A-A section
line
shown in Figure 1B. Again, ambient gas 200 may be ingested into the display
through
the inlet aperture 24 and pass through a heat exchanger 45 and exit the
display through
the exit aperture 25. The ambient gas 200 may be drawn into the display and
forced
through the heat exchanger 45 using heat exchanger fan assembly 46. Obviously,
the
inlet aperture 24 may contain a filter or ether coverings so that
contaminates, insects,
garbage, and/or water/fluids cannot easily be ingested into the display.
However, an
exemplary embodiment would not be damaged if the ambient gas 200 contained
contaminates as they would only pass through the heat exchanger 45 which may
not be
susceptible to damage from particulate or contaminates. Exit aperture 25 may
also
contain some type of covering to ensure that contaminates and/or insects could
not
enter the display.
[00421 An electronic image assembly 50 may be placed behind the front plate
10. A
plurality of channels 60 may be placed behind (preferably immediately behind)
the
9
STL=TCNI/PCT-CDA
CA 2809019 2017-11-28
electronic image assembly 50. Ambient gas 210 may be forced through the
channels
60 after travelling through the first manifold 30 (not shown here). The flow
of ambient
gas 210 immediately behind the electronic image assembly 50 may be used to.
remove
any buildup of heat from the rear portion of the electronic image assembly 50.
It may
be preferable to have a thermally conductive surface on the rear portion of
the
electronic image assembly 50 so that heat can easily transfer to this plate
and be
removed by the ambient gas 210.
[0043] The channels 60 can take on any number of forms. Although shown in this
embodiment with a square cross-section this is not required. Other embodiments
may
contain channels 60 with I-beam cross-sections, hollow square cross-sections,
hollow
rectangular cross-section, solid rectangular or solid square cross-sections,
'T' cross-
sections, 7' cross-sections, a honeycomb cross-section, or any combination or
mixture
of these. The channels 60 are preferably thermally conductive and also
preferably in
thermal communication with the electronic image assembly 50. Thus, in a
preferred
embodiment, heat which accumulates on the rear portion of the electronic image
assembly 50 may be transferred throughout the channels 60 and removed by
ambient
gas 210.
[0044] FIGURE 4 provides a perspective sectional view along the B-B section
line
shown in Figure 1B. In this view, the path of the circulating gas 250 can also
be
observed. The space between the front plate 10 and the electronic image
assembly 50
may define a front channel 251, through which the circulating gas 250 may
travel in
order to remove any accumulation of heat on the front surface of the
electronic image
assembly 50. The circulating gas 250 is preferably then directed into the heat
exchanger 45 where heat may be transferred from the circulating gas 250 to the
ambient gas 200. Upon exiting the heat exchanger 45, the circulating gas 250
may be
STL-TCN/PCT=CDA
CA 2809019 2017-11-28
re-directed into the front channel 251. The circulating gas 250 may also be
directed
over various electronic components 7 so that heat may be transferred from the
electronic components 7 to the circulating gas 250. The electronic components
7 could
be any one of the following but not limited to: power modules, heat sinks,
capacitors,
motors, microprocessors, hard drives, AC/DC converters, transformers, or
printed circuit
boards.
[00451 Also shown in this sectional view is the path of the ambient gas 210
travelling
down one of the channels 60 directly behind the electronic image assembly 50.
In this
embodiment, the ambient gas 210 is forced out of the first manifold 30, across
the
channels 60, and into the second manifold 35 by manifold fan assembly 211. As
shown in this Figure, the paths of the ambient gas 210 and the circulating gas
250 will
likely cross, but it is preferable to keep the two gases from mixing (as the
ambient gas
210 may contain particulate or contaminates while the circulating gas 250 can
remain
substantially free of particulate and contaminates). It may be preferable to
keep the
circulating gas 250 from having particulate or contaminates because it travels
in front of
the electronic image assembly 50. Thus, to keep the image quality from being
impaired, it may be desirable to keep the circulating gas 250 clean and
prevent it from
mixing with the ambient gas 210.
(0046] FIGURE 5 provides a perspective sectional view of insert C shown in
Figure 4.
As noted above, if practicing an embodiment which uses ambient gas 210 as well
as
the circulating gas 250, the pathways of the two gases may need to cross over
one
another and it may be desirable to prohibit them from mixing to prevent
contamination
of sensitive portions of the display. Here, cross through plate 500 allows the
pathways
of the two gases to cross over one another without letting them mix together.
The cross
through plate 500 in this embodiment contains a series of voids which pass
through the
plate. A first series of voids 550 passes through the cross through plate 500
and allows
ambient gas 210 to travel from the first manifold 30 into the channels 60
which run
behind the electronic image assembly 50. A second series of voids 525 pass
through
the cross through plate 500 in a direction substantially perpendicular to that
of the first
series of voids 550. The second series of voids 525 allows the circulating gas
to exit
the front channel 251, cross over the ambient gas 210, and continue towards
the heat
exchanger 45. In this embodiment, a circulating gas fan assembly 255 is
used=to draw
11
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
the circulating gas 250 through the front channel 251 and through the heat
exchanger
45. Much like the other fan assemblies shown and described here, the
circulating gas
fan assembly 255 could be placed anywhere within the display, including but
not limited
to the entrance/exit of the heat exchanger 45 or the entrance/exit of the
front channel
251.
[0047] FIGURE 6 provides a perspective sectional view of one embodiment of the
cross through plate 500. In this embodiment, the cross through plate 500 is
comprised
of a plurality of hollow blocks 503 sandwiched between a top plate 501 and
bottom
plate 502 with sections of the plates 501 and 502 removed to correspond with
the
hollow sections of the blocks 503. A portion of the top plate 501 has been
removed to
show the detail of the hollow blocks 503, first series of voids 550, and
second series of
voids 525. The cross through plate 500 could take on any number of forms and
could
be constructed in a number of ways. Some other embodiments may use a solid
plate
where the first and second series of voids 550 and 525 are cut out of the
solid plate.
Other embodiments could use two sets of hollow blocks where the hollow
sections are
perpendicular to each other and the blocks are fastened together. Still other
embodiments could use a design similar to those that are taught below for the
heat
exchanger 45, for example any type of cross-flow heat exchanger design could
be
used.
[0048] FIGURE 7 provides an exploded perspective view of one embodiment of the
heat exchanger 45. In this view, the heat exchanger fan assembly 46 is shown
removed from its mounted position within the heat exchanger 45, In this
embodiment,
the heat exchanger 45 is divided into two portions 47 and 48 where the fan
assembly
46 is placed between the two portions 47 and 48. While the fan assembly 46 can
be
placed anywhere so that it draws ambient gas 200 through the heat exchanger
45, it
has been found that placing the fan assembly 46 between the two portions of
the heat
exchanger can provide a number of benefits. First, the volumetric flow rate of
the
ambient gas 200 through the heat exchanger is high, which results in better
cooling
capabilities for the heat exchanger 45. Second, the noise produced by the fan
.
assembly 46 can ,be drastically reduced because the surrounding portions 47
and 48 of
12
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
the heat exchanger 45 essentially act as a muffler for the fan assembly 46. In
this
embodiment, portion 48 is thinner and longer than portion 47. This was done in
order
to free up more space within the housing 50 that additional electronic
components could
fit within the housing (adjacent to portion 48). This design may be preferable
when it is
desirable to create the largest possible heat exchanger 45 (for maximum
cooling
abilities). This is of course not required, and other embodiments may have
portions
which are of equal width and length. Also, although this embodiment uses the
fan
assembly 46 to drive the ambient gas 200, other embodiments could use a fan
assembly placed within the heat exchanger to drive the circulating gas 250
instead and
drive the ambient gas 200 with another fan assembly (possibly placed within
the heat
exchanger or located at the entrance/exit of the heat exchanger).
[00491 The ambient gas 200 travels through a first pathway (or plurality of
pathways)
of the heat exchanger 45 while the circulating gas 250 travels through a
second
pathway (or plurality of pathways) of the heat exchanger 45. Although not
required, it is
preferable that the circulating gas 250 and ambient gas 200 do not mix. This
may
prevent any contaminates and/or particulate that is present within the ambient
gas 200
from harming the interior of the display. In a preferred embodiment, the heat
exchanger
45 would be a cross-flow heat exchanger. However, many types of heat
exchangers
are known and can be used with any of the embodiments herein. The heat
exchanger
45 may be a cross-flow, parallel flow, or counter-flow heat exchanger. In an
exemplary
embodiment, the heat exchanger 45 would be comprised of a plurality of stacked
layers
of thin plates. The plates may have a corrugated, honeycomb, or tubular
design, where
a plurality of channels/pathways/tubes travel down the plate length-wise. The
plates
may be stacked such that the directions of the pathways are alternated with
each
adjacent plate, so that each plate's pathways are substantially perpendicular
to the
pathways of the adjacent plates. Thus, ambient gas or circulating gas may
enter an
exemplary heat exchanger only through plates whose channels or pathways travel
parallel to the path of the gas. Because the plates are alternated, the
circulating gas
and ambient gas may travel in plates which are adjacent to one another and
heat may
be transferred between the two gases without mixing the gases themselves (if
the heat
exchanger is adequately sealed, which is preferable but not required). In
other words,
=
13
STL-TCNIPCT-CDA
CA 2809019 2017-11-28
an exemplary heat exchanger would have at least a first gas pathway for
ambient gas
and at least a second gas pathway for circulating gas, where the two pathways
are
substantially perpendicular and adjacent to each other and do not allow the
ambient
gas and circulating gas to mix.
[0050] In an alternative design for a heat exchanger, an open channel may be
placed
in between a pair of corrugated, honeycomb, or tubular plates. The open
channel may
travel in a direction which is perpendicular to the pathways of the adjacent
plates. This
open channel may be created by running two strips of material or tape (esp.
very high
bond (VHB) tape) between two opposite edges of the plates in a direction that
is
perpendicular to the direction of the pathways in the adjacent plates. Thus,
gas
entering the heat exchanger in a first direction may travel through the open
channel
(parallel to the strips or tape). Gas which is entering in a second direction
(substantially
perpendicular to the first direction) would travel through the pathways of the
adjacent
plates).
[0051] Other types of cross-flow heat exchangers could include a plurality of
tubes
which contain the first gas and travel perpendicular to the path of the second
gas. As
the second gas flows over the tubes containing the first gas, heat is
exchanged
between the two gases. Obviously, there are many types of cross-flow heat
exchangers and any type would work with the embodiments herein.
[0052] An exemplary heat exchanger may have plates where the sidewalls have a
relatively low thermal resistance so that heat can easily be exchanged between
the two
gases. A number of materials can be used to create the heat exchanger.
Preferably,
the material used should be corrosion resistant, rot resistant, light weight,
and
inexpensive. Metals are typically used for heat exchangers because of their
high
thermal conductivity and would work with these embodiments. However, it has
been
discovered that plastics and composites can also satisfy the thermal
conditions for
electronic displays. An exemplary embodiment would utilize polypropylene as
the
material for constructing the plates for the heat exchanger. It has been found
that
although polypropylene may seem like a poor thermal conductor, the large
amount of
surface area relative to a small siclewall thickness, results in an overall
thermal
resistance that is low. Thus, an exemplary heat exchanger would be made of
plastic
14
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
and would thus produce a display assembly that is thin and lightweight.
Specifically,
corrugated plastic may be used for each plate layer where they are stacked
together in
alternating fashion (i.e. each adjacent plate has channels which travel in a
direction
perpendicular to the surrounding plates).
[0053] FIGURE 8 provides a perspective sectional view of another embodiment
which
uses a flow of circulating gas 350 through the backlight cavity of a liquid
crystal display
(LCD) 300. In this embodiment, a LCD 300 and an associated backlight 320 are
used
as the electronic image assembly. A backlight wall 330 may be placed between
the
LCD 300 and the backlight 320 in order to enclose the area and create a
backlight
cavity. Typically, the backlight cavity is closed to prevent
contaminates/particulate from
entering the backlight cavity and disrupting the optical/electrical functions
of the
backlight 320. However, as discussed above the exemplary embodiments may use a
clean gaseous matter for the circulating gases which could now be used to
ventilate the
backlight cavity in order to cool the backlight 320 and even the rear portion
of the LCD
300. An opening 340 can be placed in the backlight wall 330 to allow
circulating gas
350 to flow through the backlight cavity. A fan assembly 360 may be used to
draw the
circulating gas 350 through the backlight cavity. In an exemplary embodiment
there
would be an opening on the opposing backlight wall (on the opposite side of
the display
as shown in this figure) so that circulating gas 350 could easily flow through
the
backlight cavity.
[0054] FIGURE 9 provides a perspective sectional view of an exemplary
embodiment
which uses a flow of circulating gas 350 through the backlight cavity in
addition to the
flow of circulating gas 250 between the LCD 300 and front plate 10.
Circulating gas fan
assembly 255 may be placed so that it can draw circulating gas 350 through the
backlight cavity as well as circulating gas 250 between the LCD 300 and the
front plate
10. As discussed above, the circulating gases 250 and 350 are preferably
forced
through the heat exchanger 45 (not shown in this figure) so that they may be
cooled by
the ambient gas 200 (also not shown in this figure).
[0055] Also shown in Figure 9 is the optional additional flow of ambient
gas 210
which may travel immediately behind the backlight 320. Once travelling through
the
first manifold 30, the ambient gas 210 may pass through the channels 60 in
order to
15 =
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
remove heat from the backlight 320 and even the channels 60 themselves (if
they are
thermally conductive). The manifold fan assembly 21'i may be used to draw the
ambient gas 210 into the first manifold 30 and through the channels 60. Again,
the
cross though plate 500 may be used to allow the circulating gases 350 and 250
to cross
paths with the ambient gas 210 without letting the two gases mix.
[0056] In an exemplary embodiment, the backlight 320 would contain a plurality
of
LEDs mounted on a thermally conductive substrate (preferably a metal core
PCB). On
the surface of the thermally conductive substrate which faces the channels 60
there
may be a thermally conductive front plate which may be in thermal
communication with
the channels 60. In an exemplary embodiment, the thermally conductive plate
would
be metallic and more preferably aluminum.
[0057] FIGURE 10 provides a rear perspective view of an embodiment 1000 using
a
single fan assembly 1050 to control the flow of ambient gas. The embodiment
1000 is
shown here with the rear cover removed. In this figure, the main display
assembly is
still within the exterior display housing 1001. Similar to some of the
embodiments
describe above, a circulating gas fan assembly 1105 may be used to draw
circulating
gas 1106 into and through the heat exchanger 1100. Further, another
circulating gas
fan assembly 1205 may be used to draw circulating gas 1106 through heat
exchanger
1200. The circulating gas 1106 may also be used to extract heat from various
electrical
components 1109.
[0058] An ambient gas fan assembly 1050 may be used to draw ambient gas into
the
inlet aperture 1009 and exhaust the ambient gas out of an exit aperture 1010.
The
ambient gas preferably travels through the heat exchangers 1200 and 1100 as
well as
the channel behind the electronic image assembly (if used). The section line
11A-11A
is shown cutting horizontally through the display embodiment 1000.
[0059] FIGURE liA provides a perspective sectional view of the embodiment from
Figure 10 based on section line 11A-11A shown in Figure 10. For clarity, the
exterior
housing 1001 has been removed, Once the circulating gas 1106 has traveled
through
the heat exchangers 1200 and 1100, it may then be directed between the front
transparent plate 1500 and the electronic image assembly 1600. After passing
between the front transparent plate 1500 and the electronic image assembly
1600, the
16
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
circulating gas 1106 may then return to the heat exchangers 1200 and 1100. In
this
embodiment, fan assembly 1050 is used to control the flow of ambient gas 1055
and
1056. Ambient gas 1055 is directed through the heat exchangers 1200 and 1100
while
ambient gas 1056 is directed behind the electronic image assembly 1600.
[0060] FIGURE 11B provides a perspective sectional view of insert B from
Figure
11A, The channel 1700 may be defined by the space between the rear surface or
portion of the electronic image assembly 1600 and a plate which is
substantially parallel
to the rear surface or portion of the electronic image assembly 1600. The
channel 1700
may also contain ribs which are also thermally conductive and preferably in
thermal
communication with the electronic image assembly 1600. By placing the fan
assembly
1050 so as to direct the ambient gas within the channel 1700 and the heat
exchangers
1200 and 1100 simultaneously, several improvements can be achieved, including
but
not limited to: increased air flow, less fan noise, and a less
expensive/lighter assembly.
In this embodiment, the paths for ambient gas 1055 and ambient gas 1056 are
substantially parallel to one another.
[0061] As noted above, many electronic image assemblies (especially LEDs,
LCDs,
and OLEDs) may have performance properties which vary depending on
temperature.
When 'hot spots' are present within an image assembly, these hot spots can
result in
irregularities in the resulting image which might be visible to the end user.
Thus, with
the embodiments described herein, the heat which may be generated by the image
assembly (sometimes containing a backlight assembly) can be distributed
(somewhat
evenly) throughout the channels 60 and thermally-conductive surfaces to remove
hot
spots and cool the backlight and/or electronic image assembly.
[0062] The circulating gases and ambient gases can be any number of gaseous
matters. In some embodiments, air may be used as the gas for all. Preferably,
because the circulating gases may travel in front of the image assembly and/or
within
the backlight cavity, they should be substantially clear, so that they will
not affect the
appearance of the image to a viewer. The circulating gases should also
preferably be
substantially free of contaminates and/or particulate (ex. dust, dirt, pollen,
water vapor,
smoke, etc.) in order to prevent an adverse effect on the image quality and/or
damage
to the internal electronic components. It may sometimes be preferable to keep
ambient
17
STL-TCIWPCT-CDA
CA 2809019 2017-11-28
gases from having contaminates as well. Filters may be used to help reduce the
particulate within ambient gases. Filters could be placed near the inlet
apertures so
that ambient gases could be drawn through the filter. However, in an exemplary
embodiment the display may be designed so that contaminates could be present
within
the ambient gases but this will not harm the display. In these embodiments,
the heat
exchanger, manifolds, channels, and any other pathway for ambient or
circulating gas
should be properly sealed so that any contaminates in the ambient gas would
not enter
sensitive portions of the display. Thus, in these exemplary embodiments,
ingesting
ambient air for the ambient gases, even if the ambient air contains
contaminates, will
not harm the display. This can be particularly beneficial when the display is
used in
outdoor environments or indoor environments where contaminates are present in
the
ambient air.
[0063] The cooling system may run continuously. However, if desired,
temperature
sensing devices (not shown) may be incorporated within the electronic display
to detect
when temperatures have reached a predetermined threshold value. In such a
case, the
various cooling fans may be selectively engaged when the temperature in the
display
reaches a predetermined value. Predetermined thresholds may be selected and
the
system may be configured to advantageously keep the display within an
acceptable
temperature range. Typical thermostat assemblies can be used to accomplish
this
task. Thermocouples may be used as the temperature sensing devices.
(00641 It is to be understood that the spirit and scope of the disclosed
embodiments
provides for the cooling of many types of displays. By way of example and not
by way
of limitation, embodiments may be used in conjunction with any of the
following
electronic image assemblies: LCD (all types), light emitting diode (LED),
organic light
emitting diode (OLED), field emitting display (FED), light emitting
polymer (LEP), organic electro luminescence (OEL), plasma displays, and any
other
thin panel electronic image assembly. Furthermore, embodiments may be used
with
displays of other types including those not yet discovered. In
particular, it is
contemplated that the system may be well suited for use with full color, flat
panel OLED
displays. Exemplary embodiments may also utilize large (55 inches or more) LED
backlit, high definition liquid crystal displays (LCD). While the embodiments
described
18
STL-TCNIFCT-CDA
CA 2809019 2017-11-28
=
herein are well suited for outdoor environments, they may also be appropriate
for indoor
applications (e.g., factoryfindustrial environments, spas, locker rooms) where
thermal
stability of the display may be at risk.
[0065] As is well known in the art, electronic displays can be oriented in a
portrait
manner or landscape manner and either can be used with the embodiments herein.
Although circulating gas may be shown traveling clockwise or counterclockwise,
either
orientation may be used with any of the embodiments herein. Similarly,
although
ambient gas may be shown travelling from top-bottom, bottom-top, left-right,
or right-
left, any arrangement can be used. Further, it should be understood that the
figures
herein are not necessarily drawn to scale, and some components may be enlarged
for
clarity and explanatory purposes.
[0066] Having shown and described preferred embodiments, those skilled in the
art
will realize that many variations and modifications may be made to affect the
described
embodiments and still be within the scope of the claimed invention.
Additionally, many
of the elements indicated above may be altered or replaced by different
elements which
will provide the same result and fall within the spirit of the claimed
invention, It is the
intention, therefore, to limit the invention only as indicated by the scope of
the claims.
19
STL-TCN/PCT-CDA
CA 2809019 2017-11-28
