Note: Descriptions are shown in the official language in which they were submitted.
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OPTICALLY SENSING THE DEPRESSION OF A TOUCH-SCREEN
Field of Technology
[0001] The present disclosure relates to electronic devices including, but not
limited to, portable electronic devices having touch-sensitive displays and
their
control.
Background
[0002] Electronic devices, including portable electronic devices, have gained
widespread use and may provide a variety of functions including, for example,
telephonic, electronic messaging and other personal information manager (PIM)
application functions. Portable electronic devices include, for example,
several
types of mobile stations such as simple cellular telephones, smart telephones,
wireless personal digital assistants (PDAs), tablet computer, and laptop
computers with wireless 802.11 or Bluetooth capabilities.
[0003] Portable electronic devices such as PDAs or smart telephones are
generally intended for handheld use and ease of portability. Smaller devices
are
generally desirable for portability. A touch-sensitive display, also known as
a
touchscreen display, is particularly useful on handheld devices, which are
small
and have limited space for user input and output. The information displayed on
the touch-sensitive displays may be modified depending on the functions and
operations being performed. With continued demand for decreased size of
portable electronic devices, touch-sensitive displays continue to decrease in
size.
[0004] Improvements in devices with touch-sensitive displays are desirable.
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Brief Description of the Drawings
[0005] FIG. 1 is a block diagram of a portable electronic device in accordance
with the disclosure.
[0006] FIG. 2 is a sectional side view of a portable electronic device with a
mechanical actuator in accordance with the disclosure.
[0007] FIG. 3 is a sectional side view of a portable electronic device with a
depressed mechanical actuator in accordance with the disclosure.
[0008] FIG. 4 is a sectional side view of a portable electronic device with
piezoelectric actuators in accordance with the disclosure.
[0009] FIG. 5 is a sectional side view of an electronic device with a
depression
sensor in accordance with the disclosure.
[0010] FIG. 6 is a sectional side view of a touch-sensitive display that is
not
depressed in accordance with the disclosure.
[0011] FIG. 7 is a side view of a touch-sensitive display that is depressed in
accordance with the disclosure.
[0012] FIG. 8 is a flowchart illustrating a method of detecting depression of
a
touch-sensitive display in accordance with the disclosure.
[0013] FIG. 9 is a sectional side view of a touch-sensitive display that is
not
depressed in accordance with the disclosure.
[0014] FIG. 10 is a sectional side view of a touch-sensitive display that is
depressed in accordance with the disclosure.
[0015] FIG. 11 illustrates an example pattern that may be used in accordance
with the disclosure.
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[0016] FIG. 12 is a flowchart illustrating a method of detecting depression of
a
touch-sensitive display in accordance with the disclosure.
Detailed Description
[0017] The following describes apparatus for and method of detecting
depression of, or force exerted on, a touch-sensitive display of, for example,
an
electronic device. When depression of a movable touch-sensitive display is
detected, selection or confirmation of a selection occurs, and an associated
function is performed.
[0018] For simplicity and clarity of illustration, reference numerals may be
repeated among the figures to indicate corresponding or analogous elements.
Numerous details are set forth to provide an understanding of the embodiments
described herein. The embodiments may be practiced without these details. In
other instances, well-known methods, procedures, and components have not
been described in detail to avoid obscuring the embodiments described. The
description is not to be considered as limited to the scope of the embodiments
described herein.
[0019] The disclosure generally relates to an electronic device, which is a
portable electronic device in the embodiments described herein. Examples of
portable electronic devices include mobile, or handheld, wireless
communication
devices such as pagers, cellular phones, cellular smart-phones, wireless
organizers, personal digital assistants, wirelessly enabled notebook
computers,
tablet computers, and so forth. The portable electronic device may also be a
portable electronic device without wireless communication capabilities, such
as a
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handheld electronic game device, digital photograph album, digital camera, or
other device.
[0020] A block diagram of an example of a portable electronic device 100 is
shown in FIG. 1. The portable electronic device 100 includes multiple
components, such as a processor 102 that controls the overall operation of the
portable electronic device 100. Communication functions, including data and
voice communications, are performed through a communication subsystem 104.
Data received by the portable electronic device 100 is decompressed and
decrypted by a decoder 106. The communication subsystem 104 receives
messages from and sends messages to a wireless network 150. The wireless
network 150 may be any type of wireless network, including, but not limited
to,
data wireless networks, voice wireless networks, and networks that support
both
voice and data communications. A power source 142, such as one or more
rechargeable batteries or a port to an external power supply, powers the
portable electronic device 100.
[0021] The processor 102 interacts with other components, such as Random
Access Memory (RAM) 108, memory 110, a display 112 with a touch-sensitive
overlay 114 operably coupled to an electronic controller 116 that together
comprise a touch-sensitive display 118, one or more actuators 120, one or more
force sensors 122, an auxiliary input/output (I/O) subsystem 124, a data port
126, a speaker 128, a microphone 130, short-range communications 132, and
other device subsystems 134. User-interaction with a graphical user interface
is
performed through the touch-sensitive overlay 114. The processor 102 interacts
with the touch-sensitive overlay 114 via the electronic controller 116.
Information, such as text, characters, symbols, images, icons, and other items
that may be displayed or rendered on a portable electronic device, is
displayed
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on the touch-sensitive display 118 via the processor 102. The processor 102
may interact with an accelerometer 136 that may be utilized to detect
direction
of gravitational forces or gravity-induced reaction forces.
[0022] To identify a subscriber for network access, the portable electronic
device 100 uses a Subscriber Identity Module or a Removable User Identity
Module (SIM/RUIM) card 138 for communication with a network, such as the
wireless network 150. Alternatively, user identification information may be
programmed into memory 110.
[0023] The portable electronic device 100 includes an operating system 146
and software programs or components 148 that are executed by the processor
102 and are typically stored in a persistent, updatable store such as the
memory
110. Additional applications or programs may be loaded onto the portable
electronic device 100 through the wireless network 150, the auxiliary I/O
subsystem 124, the data port 126, the short-range communications subsystem
132, or any other suitable subsystem 134.
[0024] A received signal such as a text message, an e-mail message, or web
page download is processed by the communication subsystem 104 and input to
the processor 102. The processor 102 processes the received signal for output
to the display 112 and/or to the auxiliary I/O subsystem 124. A subscriber may
generate data items, for example e-mail messages, which may be transmitted
over the wireless network 150 through the communication subsystem 104. For
voice communications, the overall operation of the portable electronic device
100 is similar. The speaker 128 outputs audible information converted from
electrical signals, and the microphone 130 converts audible information into
electrical signals for processing.
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[0025] The touch-sensitive display 118 may be any suitable touch-sensitive
display, such as a capacitive, resistive, infrared, surface acoustic wave
(SAW)
touch-sensitive display, strain gauge, optical imaging, dispersive signal
technology, acoustic pulse recognition, and so forth, as known in the art. A
capacitive touch-sensitive display includes a capacitive touch-sensitive
overlay
114. The overlay 114 may be an assembly of multiple layers in a stack
including, for example, a substrate, a ground shield layer, a barrier layer,
one or
more capacitive touch sensor layers separated by a substrate or other barrier,
and a cover. The capacitive touch sensor layers may be any suitable material,
such as patterned indium tin oxide (ITO). The overlay 114 may comprise one or
more materials such as glass, plastic, polymer, and so forth. The touch-
sensitive display 118 displays information using one or more of light emitting
diodes, organic light emitting diodes, liquid crystal displays, thin film
transistor
liquid crystal displays, plasma displays, cathode ray tube displays, and so
forth.
[0026] One or more touches, also known as touch contacts or touch events,
may be detected by the touch-sensitive display 118. The processor 102 may
determine attributes of the touch, including a location of a touch. Touch
location
data may include an area of contact or a single point of contact, such as a
point
at or near a center of the area of contact. The location of a detected touch
may
include x and y components, e.g., horizontal and vertical components,
respectively, with respect to one's view of the touch-sensitive display 118.
For
example, the x location component may be determined by a signal generated
from one touch sensor, and the y location component may be determined by a
signal generated from another touch sensor. A signal is provided to the
controller 116 in response to detection of a touch. A touch may be detected
from any suitable object, such as a finger, thumb, appendage, or other items,
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for example, a stylus, pen, or other pointer, depending on the nature of the
touch-sensitive display 118. Multiple simultaneous touches may be detected.
[0027] The optional actuator(s) 120 may be depressed by applying sufficient
force to the touch-sensitive display 118 to overcome the actuation force of
the
actuator 120. Force as utilized throughout the specification refers to force
measurements, estimates, and/or calculations, such as pressure, deformation,
stress, strain, force density, force-area relationships, thrust, torque, and
other
effects that include force or related quantities. The actuator 120 may be
actuated by pressing anywhere on the touch-sensitive display 118. The actuator
120 may provide input to the processor 102 when actuated. Actuation of the
actuator 120 may result in provision of tactile feedback. When force is
applied,
the touch-sensitive display 118 is depressible, pivotable, and/or movable. The
actuator may be any suitable actuator, including mechanical and/or electrical
actuators.
[0028] A sectional side view of a portable electronic device 100 with a
mechanical actuator 120 is shown in FIG. 2. The cross section is taken through
the center of the actuator 120. The portable electronic device 100 includes a
housing 202 that encloses components such as shown in FIG. 1. The housing
202 may include a back 204, a frame 206, and sidewalls 208 that extend
between the back 204 and the frame 206. A base 210 extends between the
sidewalls 208, generally parallel to the back 204, and supports the actuator
120.
In the example of FIG. 2, a mechanical dome switch actuator is utilized. The
touch-sensitive display 118 may be supported on a support tray 212 of suitable
material, such as magnesium, and the support tray 212 may be biased away
from the base 210 toward the frame 206 by biasing elements 214, such as gel
pads or springs, between the support tray 212 and the base 210. Compliant or
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compressible spacers 216, which may be, for example, gel pads or springs, may
be located between the support tray 212 and the frame 206. The support tray
212 may be flexible. For purposes of this specification, the support tray 212
may be considered to be part of the touch-sensitive display 118, and optical
signals may be emitted toward and reflected by the support tray 212.
Optionally, the optical signals may be emitted toward openings in the support
tray 212 through which a surface of the display 112 or other part of the touch-
sensitive display 118 is visible.
[0029] The touch-sensitive display 118 may be moveable and depressible with
respect to the housing 202, and in this example is shown floating with respect
to
the housing 202, i.e., not fastened to the housing 202. As the touch-sensitive
display 118 is moved toward the base 210, the biasing elements 214 are
compressed, and when sufficient force is applied, the actuator 120 is
depressed
or actuated as shown in FIG. 3. The touch-sensitive display 118 may also pivot
within the housing to depress the actuator 120. A force 302 applied to one
side
of the touch-sensitive display 118 moves the display 118 toward the base 210,
causing compression of the biasing elements 214 on that side of the touch-
sensitive display 118 and depressing the actuator 120. The actuator 120 may
be actuated by pressing anywhere on the touch-sensitive display 118. The
processor 102 receives a signal when the actuator 120 is depressed or
actuated,
which signal may trigger a selection or other input to the portable electronic
device 100. For a mechanical dome switch/actuator, tactile feedback is
provided
when the dome collapses due to imparted force and when the dome
switch/actuator returns to the rest position after release of the switch.
Although
a single actuator is shown, any suitable number of actuators may be utilized
and
may be located in any suitable position(s).
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[0030] A sectional side view of a portable electronic device with
piezoelectric
(piezo) actuators is shown in FIG. 4. The actuator 120 may comprise one or
more piezo devices 402 that provide tactile feedback for the touch-sensitive
display 118. Four piezo devices 402 are utilized in this example, one disposed
near each corner of the device 100. The cross-section of FIG. 4 is taken
through
the centers of two of the four piezo devices 402 utilized in this example. The
piezo devices 402 may be disposed between the base 210 and the support tray
212. Each piezo actuator 120 includes a piezoelectric device, such as a
piezoelectric ceramic disk 402 adhered to a substrate 404. The substrate 404
is
elastically deformable, and may be comprised of metal, such that the substrate
404 bends when the piezo device 402 contracts, e.g., diametrically. The piezo
device 402 may contract, for example, as a result of build-up of
charge/voltage
at the piezo device 402 or in response to a force, such as an external force
applied to the touch-sensitive display 118. Each substrate 404 and piezo
device
402 may be suspended from a support, such as a ring-shaped frame 406, for
supporting the piezo device 402 while permitting flexing of the piezo actuator
120 as shown in FIG. 4. The support rings 406 may be disposed on the base
210 or may be part of the base 210, which may be a printed circuit board in a
fixed relation to at least a part of the housing 202. Optionally, the
substrate 404
may be mounted on a flat surface, such as the base 210. An element 408,
which may be comprised of a suitable material such as a hard rubber, silicone,
polyester, and/or polycarbonate, may be disposed between the piezo actuator
402 and the touch-sensitive display 118. This element 408 may provide a
bumper or cushion for the piezo actuator 120 as well as facilitate actuation
of
the piezo actuator and/or one or more force sensors 122 that may be disposed
between the piezo actuators 120 and the touch-sensitive display 118. The
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element 408 does not substantially affect the tactile feedback provided to the
touch-sensitive display 118. As the touch-sensitive display 118 is moved
toward
the base 210, when sufficient force is applied, the actuator 120 of FIG. 4 is
depressed or actuated. The processor 102 receives a signal when the actuator
120 is depressed or actuated, which signal may trigger a selection of a
displayed
selection option or other input to the portable electronic device 100 and
optionally provide tactile feedback. As described below, a depression sensor,
also referred to as an optical depression sensor, comprising one or more
optical
devices may alternatively or additionally provide the signal that triggers
selection of a displayed selection option or other input to the electronic
device
100, and may optionally trigger provision of tactile feedback by the piezo
actuators 120.
[0031] Contraction of the piezo actuators 120 applies a spring-like force, for
example, opposing a force externally applied to the touch-sensitive display
118
or providing tactile feedback in response to another event, such as an
incoming
call or other situation that results in provision of tactile feedback. The
charge/voltage may be adjusted by varying the applied voltage or current,
thereby controlling the force applied by the piezo devices 402. The
charge/voltage across the piezo actuator 120 may be removed or reduced, for
example, by a controlled discharge current that causes the piezo device 402 to
expand, releasing or decreasing the force applied by the piezo device 402. The
charge/voltage may advantageously be reduced over a relatively short period of
time to provide tactile feedback to the user via the touch-sensitive display
118.
Absent an external force and absent a charge/voltage across the piezo device
402, the piezo device 402 may be slightly bent due to a mechanical preload.
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[0032] The processor 102, or a separate processor or controller, may be
operably coupled to one or more drivers that control the
voltage/current/charge
across the piezo devices 402, which controls the force applied by the piezo
actuators 120 on the touch-sensitive display 118. Each of the piezoelectric
devices 402 may be controlled substantially equally and concurrently.
Optionally, the piezoelectric devices 402 may be controlled separately. The
piezo actuators 120 may be controlled to impart a force on the touch-sensitive
display as tactile feedback, for example, to simulate collapse or release of a
dome switch. The piezo actuators 120 may be controlled to provide other
tactile
feedback, for example, a vibration to notify of an incoming call or text
message.
[0033] Force information related to a detected touch on the touch-sensitive
display 118 may be utilized to highlight or select information, such as
information associated with a location of a touch, e.g., displayed selection
options. For example, a touch that does not meet a force threshold may
highlight a selection option, whereas a touch that meets a force threshold may
select or input that selection option. Meeting the force threshold also
includes
exceeding the force threshold. Selection options include, for example,
displayed
or virtual keys of a keyboard; selection boxes or windows, e.g., "cancel,"
"delete," or "unlock"; function buttons, such as play or stop on a music
player;
menu items, and so forth. Different magnitudes of force may be associated with
different functions or input. For example, a lesser force may result in
panning,
and a higher force may result in zooming.
[0034] When a force that meets the force threshold is imparted or exerted on
the touch-sensitive display 118, depression occurs. A force that meets the
force
threshold equals or exceeds the force threshold. Depression of the touch
sensitive display 118 signifies selection, also referred to as confirmation of
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selection, of a selection option displayed on the touch-sensitive display 118.
The
selection option is typically associated with a touch location. Tactile
feedback by
an actuator 120 or other mechanism, visual feedback, audible feedback, and/or
other feedback may optionally be provided to indicate selection, which
feedback
may be triggered by the depression. Indication of selection of a selection
option
includes any visible, audible, or other indicator that selection has occurred,
such
as entry of a character in a data field, performance of a function such as
playing
a song on a music player, opening of an application, sending an email, and so
forth. Utilizing a force threshold reduces the occurrence of unintended
selection,
for example, due to inadvertent, careless, or erroneous touches. The force
threshold, for example, addresses any force imparted on the touch-sensitive
display 118 that overcomes any biasing force, compression force, moves the
display an established distance, and/or any other force on the touch-sensitive
display 118 prior to depression of the touch-sensitive display 118. For
example,
the force threshold may be established to overcome at least the biasing forces
and/or the force to actuate the actuator 120 of FIG. 3. Alternatively, the
force
may be a force utilized in conjunction with the piezo actuator 120 of FIG. 4.
The
force or other action that depresses the touch-sensitive display may be
detected
by the actuator 120, such as described in various embodiments above, or by
another type of sensor, such as the optical depression sensor described
herein.
Thus, the optical depression sensor acts as a force sensor. Detection of a
force
that results in depression of the touch-sensitive display 118 may be
established
based on movement, compression, or flexing of the touch-sensitive display 118
that causes an identifiable effect on an optical signal. The identifiable
effect may
relate to phase, amplitude, reflection including a reflection characteristic,
and/or
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any other characteristic of the optical signal. The optical depression sensor
is
configured to detect the effect.
[0035] A sectional side view of a portable electronic device including an
optical
depression sensor is shown in FIG. 5. The optical depression sensor comprises
one or more optical devices 502, such as one or more optical emitters and/or
receivers, also known as detectors, that detect depression of the touch-
sensitive
display 118 through detection of changes in reflections of light emitted
toward
the touch sensitive display 118. The optical receiver may be any type of
receiver that receives or detects optical signals, such as an image sensor.
The
optical device 502 may be a paired optical emitter and an optical receiver or
detector, which may be integrated into a single package. The optical device
502
may comprise more optical receivers than optical emitters. The optical
depression sensor of the portable electronic device 100 illustrated in the
example of FIG. 5 comprises four optical devices 502, one disposed near each
corner of the device 100. For simplicity of illustration, only two optical
devices
502 are shown in FIG. 5. The cross-section of FIG. 5 is taken through the
centers of two of the optical devices 502 utilized in this example, which are
shown disposed between the base 210 and the support tray 212. In this
example, each optical device 502 includes an emitter that emits an optical
signal
and a receiver or detector that receives a reflection of the optical signal.
The
optical signal reflects off a surface that moves or deforms when the touch-
sensitive display 118 is depressed. As the touch-sensitive display 118 is
moved
toward the base 210, when sufficient force is applied, the optical device 502
of
FIG. 5 detects a change in the reflection of the optical signal. When the
processor 102 detects a change or variation in the reflection that meets a
threshold amount of change in reflection, depression of the touch-sensitive
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display 118 is detected. As shown in FIG. 5, the force 302 may cause one part
of the touch-sensitive display 118 to be closer to a first optical device 502
than
another part of the touch-sensitive display 118 is to a second optical device
502
because the touch-sensitive display 118 floats, i.e., moves relative to the
housing. The optical signals received by the first optical device 502 may
signify
depression, whereas optical signals received by the second optical device 502
may not signify depression. Depression is detected when the change in
reflection for any one or more of the optical devices 502 meets the threshold
change in reflection. The location of the optical device 502 may optionally be
utilized to determine the touch location.
[0036] As shown in the cross-sectional views in the example of FIG. 6 and
FIG. 7, the optical depression sensor includes an optical device 602 that
emits
an optical signal toward a surface, such as an external side or edge of the
touch-
sensitive display 118, and receives a reflection of the optical signal from
the
touch-sensitive display 118. The optical device 602 includes one or more
devices, such as one or more optical emitters and one or more optical
receivers
or detectors, which may be similar to the optical device 502 of FIG. 5, and
may
include, for example, an infrared transmitter and receiver, an ultra-violet
transmitter and receiver, a light amplification by stimulated emission of
radiation
(LASER) transmitter and receiver, and so forth. The touch-sensitive display
118
includes a reflective surface 604 that is shown disproportionately large for
the
sake of illustration. The reflective surface 604 may be the outer surface,
such as
a side or an edge, of the touch-sensitive-overlay 114 and/or display 112 as
manufactured, a surface or an edge of the support tray 212, or a reflective
coating or object applied to a surface of the touch-sensitive display 118, a
polished surface of the touch-sensitive display 118, and so forth. One or more
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optical emitter/receivers of the optical device 602 may be directed to each of
one or more surfaces 604 of the touch-sensitive display 118, e.g., each side
or
edge. The depression sensor may replace the mechanical actuator 120 of FIG. 2
or the piezo actuators 120 of FIG. 4. Alternatively, the mechanical actuator
120
of FIG. 2 or the piezo actuators 120 of FIG. 4 may be utilized in addition to
the
depression sensor.
[0037] As shown in FIG. 6, the optical device 602 emits an optical signal at a
wavelength, A. For simplicity of illustration, the optical signal is shown as
a
coherent optical signal having a single wavelength in FIG. 6. Alternatively,
the
optical signal may comprise light of any number of wavelengths, which may
include a primary wavelength. When the touch-sensitive display 118 is not
depressed, the distance between the optical device 602 and the reflective
surface 604 is an integer multiple, n, of A, e.g., nA. The reflected optical
signal
is received by the optical device 602 after the optical signal travels a
distance of
2nA. The distance may not be exactly 2nA, but may be substantially equal to
2nA due to small manufacturing or aging variations.
[0038] When the touch-sensitive display 118 is depressed, for example, due
to a force represented by the arrow in FIG. 6, the touch-sensitive display 118
is
bent slightly due to the force exerted on the touch-sensitive display 118.
When
the touch-sensitive display 118 is depressed, the distance between the optical
device 602 and the reflective surface 604 changes to nA plus a difference or
delta, L, due to bending or movement of the touch-sensitive display 118. LI
may
be positive or negative.
[0039] Changes in the reflected optical signal are detected by the optical
device 602. The change in the reflected optical signal may be a phase
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difference, which may be measured by a time between signal peaks, an
amplitude difference, which may be partially or totally reduced, a difference
in
the amount of time for an optical signal emitted by the optical device 602 to
reflect back to the optical device 602. For example, when touch-sensitive
display 118 is depressed, the touch-sensitive display 118 is bent, which
changes
the reflection of optical signals emitted by the optical device 602. The
change in
the reflection may cause optical signals emitted from the optical device 602
to
be diffused, absorbed, distorted, or otherwise changed, affecting the energy
or
amplitude of the optical signal, which change is detected by the optical
device
602. Alternatively, the optical signal may comprise one or more pulses of one
or
more different durations, and a time difference in receipt of consecutive
pulses
of the reflected optical signal is detected when the touch-sensitive display
118 is
depressed.
[0040] Depression of the touch-sensitive display 118 may prevent the
reflection of light emitted by the optical device 602 from being received by
the
optical device 602, may cause the reflection of light to be more directly or
less
directly received by the optical device 602, or may cause the reflection of
light to
travel a greater distance before being received by the optical device 602,
e.g.,
due to movement or deformation of the touch-sensitive display 118. Depression
of the touch-sensitive display 118 may cause reflected light to be directed
away
from the optical device 602, e.g., upward or downward. A change in the
intensity or amplitude of the reflected optical signal may be utilized to
detect a
depression.
[0041] Arrangements other than the optical device 602 of FIG.6 and FIG. 7
are possible. Alternatively, the optical device 602may emit an optical signal
toward any surface that reflects at least part of the optical signal, which
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reflection changes when the touch-sensitive display 118 is depressed. The
optical device 602 may be attached to the touch-sensitive display 118 and may
emit an optical signal and receive an optical signal reflected off another
part of
the portable electronic device 100, such as a sidewall 208 of the housing 202.
Alternatively, an optical emitter may transmit an optical signal to an optical
receiver or detector, wherein one of the optical emitter and the optical
receiver
is attached to the touch-sensitive display 118 and the other of the optical
emitter and the optical receiver is attached to another part of the portable
electronic device 100, such that the emitter and receiver move relative to one
another when the touch-sensitive display 118 is depressed.
[0042] Although the optical device 602 of FIG. 6 and FIG. 7 is disposed at a
distance from the reflective surface 604 that is an integer multiple of the
wavelength of the emitted optical signal, other arrangements are possible. The
optical device 602 may be disposed at any distance and at any angle with
respect to the reflective surface 604, and the distance and angle are taken
into
account when the reflections are analyzed.
[0043] The thresholds related to variations for an optical reflection may be
modified over long periods of time to adjust for changes in the device 100
over
time, e.g., weeks, months, or years.
[0044] The optical depression sensor of FIG. 6 and FIG. 7 may be disposed,
for example, between the touch-sensitive display 118 and the base 210. The
optical depression sensor may be disposed between other components of the
portable electronic device 100. For example, the optical depression sensor may
be disposed between the display 112 and the support tray 212, between the
overlay 114 and the display 112, or in any other suitable location.
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[0045] A flowchart illustrating a method of detecting force exerted on, or
depression of, a touch-sensitive display of a mobile device is shown in FIG.
8.
_
The method may be carried out by software executed by, for example, the
processor 102. Coding of software for carrying out such a method is within the
scope of a person of ordinary skill in the art given the present description.
The
method may contain additional or fewer processes than shown and/or described
and may be performed in a different order. Computer-readable code executable
by at least one processor of the portable electronic device to perform the
method may be stored in a computer-readable medium.
[0046] One or more optical signals are emitted 802 towards the touch-
sensitive display 118 by the optical device 602. The optical device 602 may be
enabled while the portable electronic 100 is enabled or activated, when the
portable electronic device 100 is powered up, or when selection options are
displayed to save energy. The optical device 602 directs the optical signals
towards the touch-sensitive display 118.
[0047] The optical signals reflect off the reflective surface 604. The
reflected
optical signals are evaluated or analyzed when received 804 by the optical
device 602 for a change in reflection 806 to determine whether the touch-
sensitive display is depressed. The evaluation of the reflected optical
signals
may be carried out after the reflected optical signals are converted from
optical
signals to other signals that are more easily evaluated, such as electrical
signals,
e.g., by the optical device 602. The evaluation may be carried out by a
processor or other suitable device configured to process electrical signals.
The
reflected optical signals may be evaluated for a change in reflection 806 in a
number of different ways to determine whether the touch-sensitive display is
depressed.
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[0048] One or more baseline measurements of the reflected optical signals
may be taken when the touch-sensitive display 118 is depressed and not
depressed. Baseline measurements may be carried out periodically. Reflected
optical signals received by the optical device 602 are compared to a relevant
baseline measurement. The baseline measurements may be composite
measurements, wherein one baseline is determined for all receivers of the
optical device 602. Each optical receiver may have its own baseline due to
relative placement of the components of the electronic device 100 and the
optical device 602, different reflectivity of components of the electronic
device
100, and so forth. A deviation from the baseline signifies depression when the
deviation meets a threshold, such as a change in the magnitude of a reflected
optical signal, a change in a time between emitting the optical signal and
receiving the resulting reflected optical signal, and so forth. Exceeding the
threshold is also considered meeting the threshold. Baseline measurements may
be conducted over time at regular intervals, e.g., every 10 milliseconds, 10
seconds, 10 minutes and so forth, or may be carried out upon the occurrence of
particular event, e.g., electronic device 100 power up, after an instruction
to the
user not to depress the touch-sensitive display for a period of time, and so
forth.
Baseline measurements may optionally be determined for different areas of the
touch-sensitive display 118.
[0049] Another way of determining whether the touch-sensitive displayed is
depressed 806 includes comparing a current measurement of the reflected
optical signal from the optical device 602 with a previous measurement of the
reflected optical signal from the optical device 602. The previous measurement
may be the last measurement that was obtained or any other previous
measurement. When a deviation between the current measurement and the
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previous measurement meets a threshold, depression is detected. Meeting a
threshold includes equaling or exceeding the threshold value. The deviation
may
be a change in the magnitude of a reflected optical signal, a change in a time
between emitting the optical signal and receiving the reflected optical
signal, and
so forth.
[0050] Another way of determining whether the touch-sensitive display is
depressed 806 includes evaluating reflected optical signals from multiple
optical
receivers for variations between the reflected optical signals. The reflected
optical signals from multiple optical receivers are compared to one another,
for
example, by comparing the reflected optical signal from each optical receiver
to
an average of the reflected optical signals to determine when any optical
signal
is sufficiently different than the average. When an optical signal is
sufficiently
different from the average, e.g., meeting a threshold magnitude difference,
time
delay, and so forth, depression is detected.
[0051] When a depression is detected 806, e.g., by detecting a change in
reflection, an indication of the selection is provided 808. For example, the
selection option associated with the location of the touch is processed and
the
indication of the selection is provided 808, and the process continues at 802.
[0052] As shown in the cross-sectional views in the example of FIG. 9 and
FIG. 10, the force sensor 122 includes an optical device 902 that emits an
optical signal toward the touch-sensitive display 118 and receives a
reflection of
the optical signal from the touch-sensitive display 118. The optical device
902
includes one or more optical emitters and one or more optical detectors or
receivers, which may be similar to the optical device 502 of FIG. 5 or the
optical
device 602 of FIG. 6, and may include, for example, an infrared
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transmitter/receiver, an ultra-violet transmitter/receiver, a light
amplification by
stimulated emission of radiation (LASER) transmitter/receiver, and so forth.
The
surface of the touch-sensitive display 118 includes a pattern 904, such as
shown
in FIG. 11. The pattern 904 may be any type of pattern that assists in the
optical detection of depression or movement of the touch-sensitive display.
One
or more patterns may be utilized. For example, the pattern may include
alternating areas that are more reflective and less-reflective, a repeated
shape,
such as an x or v, a pattern comprising symbols randomly located throughout
the pattern area, and so forth. The pattern may be etched, screened, printed,
adhesively attached via a substrate media, embedded in, or otherwise disposed
on, formed on, or attached to the surface of the touch-sensitive display 118.
The force sensor 122 may replace the mechanical actuator 120 of FIG. 2 or the
piezo actuators 120 of FIG. 4. Alternatively, the mechanical actuator 120 of
FIG.
2 or the piezo actuators 120 of FIG. 4 may be utilized in addition to the
optical
depression sensor of FIG. 9.
[0053] As shown in FIG. 9, the optical device 902 receives a reflection of the
pattern 904 off a reflective surface 904 of the touch-sensitive display 118.
When the touch-sensitive display 118 is depressed, for example, due to a force
represented by the arrow in FIG. 9, the touch-sensitive display 118 moves
toward the base 210 or back 204 of the housing 204. When the touch-sensitive
display 118 is depressed, the reflection of the pattern 904 received by the
optical device 902 changes from the reflection of the pattern 904 received by
the
optical device 902 when the touch-sensitive display 118 is not depressed,
e.g.,
in a resting position.
[0054] Changes in the reflected optical signal are detected by the optical
device 902. The change in the reflected optical signal may be a difference in
the
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size or part, e.g., portion or area, of the pattern detected by the optical
device
902, or other difference in reflection caused by movement of the touch-
sensitive
display. For example, when touch-sensitive display 118 is depressed, the touch-
sensitive display 118 moves toward the base 210 or back 204 of the housing
202, which changes the part of the pattern 904 received by the optical device
902. The optical device 902 may be oriented with the touch-sensitive display
such that a relatively less reflective area of the pattern 904 is reflected
when the
touch-sensitive display 118 is not depressed, and a relatively more reflective
area of the pattern 904 is reflected when the touch-sensitive display 118 is
not
depressed, which will cause a reflected optical signal to have a relatively
greater
amplitude when the touch-sensitive display 118 is depressed.
[0055] A substantive change in the reflected optical signal is detected as a
depression. For example, movement meeting a threshold distance or change in
pattern by a threshold percentage may be utilized to determine whether a
depression occurs.
[0056] Arrangements other than the optical device 902 of FIG. 9 and FIG. 10
are possible. Alternatively, the optical device 902 may emit an optical signal
towards any surface with the pattern 904, which reflection changes with
depression of the touch-sensitive display 118. The optical device 902 may be
attached to the touch-sensitive display 118 and may emit an optical signal and
receive an optical signal reflected from a surface with the pattern, which
surface
is on another part of the electronic device 100, such as a sidewall 208 of the
housing 202. Alternatively, an optical emitter may transmit an optical signal
to
an optical receiver, wherein one of the optical emitter and the optical
receiver is
attached to the touch-sensitive display 118 and the other of the optical
emitter
and the optical receiver is attached to another part of the portable
electronic
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device 100, such that the emitter and receiver move relative to one another
when the touch-sensitive display 118 is depressed.
[0057] The optical device 902 of FIG. 9 and FIG. 10 may be disposed, for
example, between the touch-sensitive display 118 and the base 210. The optical
device 902 may be disposed between other components of the portable
electronic device 100. For example, the optical device 902 may be disposed
between the display 112 and the support tray 212, between the overlay 114 and
the display 112, or in any other suitable location.
[0058] Although the optical device 902 of FIG. 9 and FIG. 10 includes an
optical emitter and an optical receiver, the optical device 902 may
alternatively
include a receiver only. Light reflected off the surface with the pattern 904
may
be from a light source such as a backlight of the touch-sensitive display,
ambient
light from outside the portable electronic device 100, an optical emitter
separate
from the optical device 902, and so forth.
[0059] As shown in FIG. 11, the pattern 904 may include several different
patterns 1102, 1104, 1106, 1108, 1110, and 1112. Alternatively, the pattern
904 may comprise one or more instances of the patterns 1102, 1104, 1106,
1108, 1110, and 1112. For illustration, areas of the patterns of FIG. 11 shown
in black are relatively less reflective than areas of the patterns shown in
white.
For example, areas that are more reflective may be darkened, etched with a
matte finish, painted with a dark color, black areas, and so forth. Areas that
are
less reflective may be polished, brightly colored, mirrored areas, white
areas,
silver areas, and so forth. Other arrangements may be used. For example, any
of the relatively more reflective areas may be made less reflective and less
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reflective areas may be made more reflective. Patterns other than those in
FIG.
11 may be used.
[0060] The angled line pattern 1102 comprises areas of alternating relatively
more reflective areas and relatively less reflective areas. The criss-crossed
pattern 1104 comprises a relatively more reflective background with crossing
lines that are relatively less reflective. The vertical pattern 1106 comprises
alternating vertical lines that are relatively more reflective and relatively
less
reflective. The x pattern 1108 comprises a grid of relatively less reflective
x's on
a relatively more reflective background. The horizontal pattern 1110 comprises
alternating horizontal lines that are relatively more reflective and
relatively less
reflective. The screen pattern 1104 comprises a relatively more reflective
background with a rectangular grid of relatively less reflective lines.
[0061] The patterns 1102, 1104, 1108, and 1112 facilitate detection, by the
optical device 902, of movement in any direction of a surface on which the
pattern is applied. The pattern 1106 facilitates detection, by the optical
device
902, of movement along the longer dimension of the pattern 1106. The pattern
1110 facilitates detection, by the optical device 902, of movement along the
shorter dimension of the pattern 1110. By varying the size of areas that are
relatively more reflective and relatively less reflective, the sensitivity of
the
optical device 902 may be varied in embodiments where the optical device 902
receives a reflection of a relatively small area and identifies depression
when the
reflection changes, e.g., when movement causes the reflection to move from a
relatively less reflective area to a relatively more reflective area. In such
embodiments, for example, the vertical pattern 1106 provide more sensitivity
than the angled line pattern 1102. When the optical device 902 receives a
reflective of a relatively larger area, the granularity of the relatively more
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reflective areas and the relatively less reflective areas may not affect the
sensitivity.
[0062] A flowchart illustrating a method of detecting force exerted on, or
depression of, a touch-sensitive display of a mobile device is shown in FIG.
12.
The method may be carried out by software executed by, for example, the
processor 102. Coding of software for carrying out such a method is within the
scope of a person of ordinary skill in the art given the present description.
The
method may contain additional or fewer processes than shown and/or described
and may be performed in a different order. Computer-readable code executable
by at least one processor of the portable electronic device to perform the
method may be stored in a computer-readable medium.
[0063] The optical device 902 may be enabled while the portable electronic
device 100 is enabled or activated, when the portable electronic device 100 is
powered up, or when selection options are displayed to save energy.
[0064] Optical signals directed toward the touch-sensitive display 118 reflect
off the surface of the touch-sensitive display 118 with the pattern 904. The
reflected optical signals are received 1202 and evaluated or analyzed by the
optical device 902 to determine whether depression of the touch-sensitive
display occurs 1204, e.g., due to change in the reflection that meets a
threshold.
Several ways of receiving and evaluating a reflection are described above with
respect to FIG. 8, which are modifiable to determine variations in the
reception
of the pattern by the optical device 902.
[0065] When a depression is detected 1204, e.g., by detecting a change in
reflection, an indication of the selection is provided 1206. For example, the
CA 02811441 2015-07-10
selection option associated with the location of the touch is processed and
the
indication of the selection is provided 1206, and the process continues at
1202.
[0066] Through the use of one or more techniques described herein,
depression of a movable touch-sensitive display may be detected without the
use of strain gauges or other mechanical devices. User experience with the
portable electronic device is enhanced, e.g., by more reliable selection and
optional tactile feedback. Detection of force applied to the touch-sensitive
display is provided with optical devices, e.g., one or more optical emitters
and
receivers, which optical devices may be utilized with existing touch-sensitive
displays. The optical depression sensor need not be in physical contact with
the
touch-sensitive display. Because changes in optical reflection are analyzed,
losses inherent in light transmission have negligible effect on the process.
[0067] The scope of the claims should not be limited by the preferred
embodiments set forth in the examples, but should be given the broadest
interpretation consistent with the description as a whole.
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