Note: Descriptions are shown in the official language in which they were submitted.
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ELECTRONIC DEVICE INCLUDING TOUCH-SENSITIVE DISPLAY AND
METHOD OF DETECTING NOISE
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 phones,
wireless
personal digital assistants (PDAs), 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.
Improvements in devices with touch-sensitive displays are desirable.
Summary
[0004] An electronic device includes a touch-sensitive display that includes
drive
electrodes and sense electrodes configured to detect touches on the touch-
sensitive
display, a noise-detection electrode spaced from the drive electrodes and the
sense
electrodes, at least one controller operably coupled to the drive electrodes,
the
sense electrodes, and the noise-detection electrode and configured to detect
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touches on the touch-sensitive display utilizing the drive electrodes and the
sense
electrodes, and detect noise utilizing the noise-detection electrode during
touch
detection. A method includes detecting touches on a touch-sensitive display of
an
electronic device by driving drive electrodes while sensing utilizing sense
electrodes,
and detecting noise by receiving signals from a noise-detection electrode
spaced
from the drive electrodes and the sense electrodes, while detecting touches on
the
touch-sensitive display. The noise-detection electrode is different from the
sense
electrodes.
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 front view of an electronic device in accordance with the
disclosure.
[0007] FIG. 3 is a flowchart illustrating a method of detecting touches in
accordance with the disclosure.
[0008] FIG. 4 is a front view of another electronic device in accordance with
the
disclosure.
Detailed Description
[0009] The following describes an electronic device and a method of detecting
noise in an electronic device. The electronic device includes drive electrodes
and
sense electrodes configured to detect touches on a touch-sensitive display.
Another
electrode, a noise-detection electrode, is spaced from the drive electrodes
and the
sense electrodes and does not cross over or under the drive electrodes or the
sense
electrodes. The noise-detection electrode is utilized to detect noise during
touch
detection. Noise may be detected while drive electrodes are driven.
[0010] For simplicity and clarity of illustration, reference numerals may be
repeated among the figures to indicate corresponding or analogous elements.
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Numerous details are set forth to provide an understanding of the examples
described herein. The examples may be practiced without these details. In
other
instances, well-known methods, procedures, and components are not described in
detail to avoid obscuring the examples described. The description is not to be
considered as limited to the scope of the examples described herein.
[0011] The disclosure generally relates to an electronic device, such as a
portable
electronic device or non-portable electronic device. 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, mobile
internet devices, electronic navigation devices, and so forth. The portable
electronic device may be a portable electronic device without wireless
communication capabilities, such as handheld electronic games, digital
photograph
albums, digital cameras, media players, e-book readers, and so forth. Examples
of
non portable electronic devices include desktop computers, electronic white
boards,
smart boards utilized for collaboration, built-in monitors or displays in
furniture or
appliances, and so forth.
[0012] 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.
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[0013] The processor 102 interacts with other components, such as a Random
Access Memory (RAM) 108, memory 110, 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. The touch-sensitive
display
118 includes a display 112 and sensors 114 that are coupled to at least one
controller 116 that is utilized to interact with the processor 102. Input via
a
graphical user interface is provided via the touch-sensitive display 118.
Information, such as text, characters, symbols, images, icons, and other items
that
may be displayed or rendered on a portable electronic device, is displayed on
the
touch-sensitive display 118 via the processor 102. The processor 102 may also
interact with an accelerometer 136 that may be utilized to detect direction of
gravitational forces or gravity-induced reaction forces.
[0014] To identify a subscriber for network access, the electronic device 100
may
utilize 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.
[0015] The electronic device 100 includes an operating system 146 and software
programs, applications, 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 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.
[0016] 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
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wireless network 150 through the communication subsystem 104. For voice
communications, the overall operation of the 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.
[0017] The touch-sensitive display 118 may be any suitable touch-sensitive
display, such as a capacitive touch-sensitive display. A capacitive touch-
sensitive
display includes one or more capacitive touch sensors. Thus, for a capacitive
touch-
sensitive display, the sensors 114 comprise capacitive touch sensors. The
capacitive touch sensors may comprise any suitable material, such as indium
tin
oxide (ITO).
[0018] 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 the touch. Touch location
data may
include data for an area of contact or data for 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. A
touch
may be detected from any suitable input member, such as a finger, thumb,
appendage, or other objects, for example, a stylus, pen, or other pointer,
depending on the nature of the touch-sensitive display 118. Multiple
simultaneous
touches may be detected.
[0019] One or more gestures may also be detected by the touch-sensitive
display
118. A gesture, such as a swipe, also known as a flick, is a particular type
of touch
on a touch-sensitive display 118 and may begin at an origin point and continue
to
an end point, for example, a concluding end of the gesture. A gesture may be
identified by attributes of the gesture, including the origin point, the end
point, the
distance travelled, the duration, the velocity, and the direction, for
example. A
gesture may be long or short in distance and/or duration. Two points of the
gesture may be utilized to determine a direction of the gesture. A gesture may
also
include a hover. A hover may be a touch at a location that is generally
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over a period of time or is associated with the same selection item for a
period of
time.
[0020] The optional actuator(s) 120 may be depressed or activated by applying
sufficient force to the touch-sensitive display 118 to overcome the actuation
force of
the actuator 120. The actuator(s) 120 may be actuated by pressing anywhere on
the touch-sensitive display 118. The actuator(s) 120 may provide input to the
processor 102 when actuated. Actuation of the actuator(s) 120 may result in
provision of tactile feedback. When force is applied, the touch-sensitive
display 118
is depressible, pivotable, and/or movable. Such a force may actuate the
actuator(s) 120. The touch-sensitive display 118 may, for example, float with
respect to the housing of the portable electronic device, i.e., the touch-
sensitive
display 118 may not be fastened to the housing. A mechanical dome switch
actuator may be utilized. In this example, tactile feedback is provided when
the
dome collapses due to imparted force and when the dome returns to the rest
position after release of the switch. Alternatively, the actuator 120 may
comprise
one or more piezoelectric (piezo) devices that provide tactile feedback for
the
touch-sensitive display 118.
[0021] Optional force sensors 122 may be disposed in conjunction with the
touch-sensitive display 118 to determine or react to forces applied to the
touch-
sensitive display 118. The force sensor 122 may be disposed in line with a
piezo
actuator 120. The force sensors 122 may be force-sensitive resistors, strain
gauges, piezoelectric or piezoresistive devices, pressure sensors, quantum
tunneling composites, force-sensitive switches, or other suitable devices.
Force as
utilized throughout the specification, including the claims, 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. Optionally, force
information related
to a detected touch may be utilized to select information, such as information
associated with a location of a touch. For example, a touch that does not meet
a
force threshold may highlight a selection option, whereas a touch that meets a
force
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threshold may select or input that selection option. 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; 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.
[0022] The touch-sensitive display 118 includes a display area in which
information may be displayed, and a non-display area extending around the
periphery of the display area. The display area generally corresponds to the
area of
the display 112. Information is not displayed in the non-display area by the
display,
which non-display area is utilized to accommodate, for example, electronic
traces or
electrical connections, adhesives or other sealants, and/or protective
coatings
around the edges of the display area. The non-display area may be referred to
as
an inactive area and is not part of the physical housing or frame of the
electronic
device. Typically, no pixels of the display are in the non-display area, thus
no
image can be displayed by the display 112 in the non-display area. Optionally,
a
secondary display, not part of the primary display 112; may be disposed under
the
non-display area. Touch sensors may be disposed in the non-display area, which
touch sensors may be extended from the touch sensors in the display area or
distinct or separate touch sensors from the touch sensors in the display area.
A
touch, including a gesture, may be associated with the display area, the non-
display
area, or both areas. The touch sensors may extend across substantially the
entire
non-display area or may be disposed in only part of the non-display area.
[0023] A front view of an electronic device 100 with a plurality of sensors
114 is
shown in the example of FIG. 2. The sensors 114 are shown for the purpose of
illustration, but are not visible to the eye when looking at the front of the
electronic
device 100.
[0024] The sensors 114 include touch-sensing electrodes comprising drive
electrodes 202 and sense electrodes 204 configured to detect touches on the
touch-
sensitive display 118. The drive electrodes 202 extend generally horizontally
and
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the sense electrodes 204 extend generally vertically in the example of FIG. 2.
The
drive electrodes 202 and the sense electrodes 204 may extend in other
directions.
For example, the drive electrodes 202 may extend generally vertically and the
sense electrodes 204 may extend generally horizontally. The terms "vertically"
and
"horizontally" are utilized herein to provide reference to an orientation of
the
electronic device 100 in the drawings and are not otherwise limiting.
[0025] The drive electrodes 202 and sense electrodes 204 may be disposed on
different planes of the touch-sensitive display 118. Alternatively, jumpers
may be
included such that the sense electrodes 204 cross over and are electrically
isolated
from the drive electrodes 202. The sensors 114 also include a noise-detection
electrode 206 that is spaced from the drive electrodes 202 and the sense
electrodes
204 such that the noise-detection electrode 206 does not cross over or under
the
drive electrodes 202 or the sense electrodes 204.
[0026] The noise-detection electrode 206 may, for example, extend around the
drive electrodes 202 and the sense electrodes 204. In the example of FIG. 2,
the
noise-detection electrode 206 is a ring that extends around the outermost
perimeter of drive electrodes 202 and the sense electrodes 204. The noise-
detection electrode 206 may also be utilized as an electrostatic discharge
ring. An
electrostatic discharge ring may be utilized as the noise-detection electrode.
[0027] The noise-detection electrode 206 may be disposed on the same layer of
the touch-sensitive display 118 as the drive electrodes 202 or the same layer
of the
touch-sensitive display 118 as the sense electrodes 204. The noise-detection
electrode 206 may be made of the same material as the drive electrodes 202 or
the
sense electrodes 204. Alternatively, the noise-detection electrode 206 may be
disposed on another layer of the touch-sensitive display 118. The noise-
detection
electrode 206 may be disposed in the display area of the touch-sensitive
display
118 and may be transparent. Alternatively, the noise-detection electrode 206
may
be disposed in the non-display area of the touch-sensitive display 118 and may
be,
for example, a non-transparent material. The noise-detection electrode 206 may
alternatively be disposed separate from the touch-sensitive display 118, such
as on
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a printed circuit board of the electronic device 100, on a housing of the
electronic
device, and so forth.
[0028] in this example, the drive electrodes 202, the sense electrodes 204,
and
the noise-detection electrode 206 are operably coupled to the controller 116.
The
controller 116 is configured to drive the drive electrodes 202 and receive
signals
from the sense electrodes 204 during touch detection. The controller 116 is
also
configured to detect noise by receiving signals from the noise-detection
electrode
206 during touch detection. The noise includes electrical noise from sources
internal to the electronic device 100, such as from the processor 102, display
112,
power source 142, speaker 128, microphone, 130, and so forth, and sources
external to the electronic device 100, such as other electrical devices or
energy
sources. For example, noise caused by charging the electronic device 100 may
be
detected. The controller 116 is configured to drive one or more drive
electrodes
202 while detecting noise utilizing the noise-detection electrode 206. At
least one
drive electrode 202 may be driven during the same period of time in which the
noise-detection electrode 206 is utilized to detect noise. The term "while",
as
utilized herein, includes: driving a drive electrode and detecting noise
during the
same period of time; driving a drive electrode 202 synchronously or
asynchronously
with detecting noise; driving a drive electrode 202 overlapping at least
partially in
time with detecting noise; driving a drive electrode such that the drive time
overlaps at least partially with the noise detection time; driving more than
one drive
electrode 202 during detecting noise. Noise detection and driving the drive
electrode may be offset in time. Noise detection may begin when driving a
drive
electrode begins or may begin at different times. Noise detection may end at
the
same time that driving the drive electrode ends or may end at a different
time.
Noise detection may be carried out during driving a plurality of the drive the
electrodes. Noise detection may be continuously performed during touch
detection.
[0029] The noise-detection electrode 206 is advantageously not a drive
electrode
202 or a sense electrode 204 that is utilized for touch detection. The noise-
detection electrode 206 does not cross over or under any of the drive
electrodes
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202 or the sense electrodes 204 to facilitate better noise detection during
touch
detection. Noise, such as noise from the display 112, may be detected during
frames of a scan to detect touches. A separate frame or frames of the scan are
not
required for noise detection. The scanning time for touch detection and noise
detection may be reduced compared to a device that utilizes a sense electrode
for
noise detection to detect noise when none of the drive electrodes are driven.
[0030] The controller 116 may be configured to alter at least one touch-
detection
parameter to reduce the effect of noise, or increase the signal-to-noise
ratio, during
touch sensing. The touch-detection parameters that are changed may include,
for
example, the frequency with which the drive electrodes 202 are driven, the
number
of pulses of signal utilized to drive the drive electrodes 202, the scanning
rate,
filtering, and so forth. For example, each drive electrode 202 may be driven
with 4
pulses when a noisy condition is not detected and may be driven with 8 pulses
when a noisy condition is detected. The time to perform a scan of the touch-
sensitive display 118 may be greater when a greater number of pulses is
utilized to
drive the drive electrodes 202, 204. When a noisy condition is detected, a
greater
number of pulses may be utilized over a longer period of time. When a noisy
condition is not detected, fewer pulses may be utilized over a shorter period
of
time. Optionally, noise filtering may be increased. For example, the order of
the
filter may be increased to increase the filtering.
[0031] The controller 116 may be configured to control touch data filtering,
to
increase or decrease touch data filtering based on the noise detected during
touch
detection, and so forth. Digital filtering such as infinite impulse response
(IIR)
filtering may be carried out to reduce the effect of noise on touch detection.
The
order of the filter may be increased or decreased based on the noise detected.
The
raw data that is utilized to generate the x and y coordinate values may be
filtered.
In addition to or instead of filtering the raw data, the x and y coordinate
values of
the touch may filtered to increase accuracy of the touch location that is
identified.
The controller 116 may also control the number of pulses of the signal that is
utilized to drive the drive electrodes 202 during touch detection. The number
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pulses of the signal may be increased or decreased during touch detection. For
example, in response to detecting noise, the number of pulses of the signal
may be
increased during touch detection to reduce the effect of noise on touch
detection.
The scanning rate of the touch-sensitive display may be altered based on noise
detected during touch detection. The controller 116 may also be configured to
alter
a time or frequency at which the drive electrodes are driven. The controller
116
may change the frequency or frequency range of scanning of the touch-sensitive
display 118 to a frequency or frequency range that is less noisy. Other
methods to
reduce the noise or the effect of noise on touch data may also be utilized
when
noise is detected during touch detection.
[0032] A flowchart illustrating a method of detecting noise on the touch-
sensitive
display 118 is illustrated in FIG. 3. The method may be carried out by
software
executed, for example, by the controller 116 and/or 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
electronic device to perform the method may be stored in a computer-readable
storage medium, device, or apparatus, which may be a non-transitory or
tangible
storage medium.
[0033] Touch detection is performed 302 to detect touches on the touch-
sensitive
display 118. The drive electrodes 202 are driven while receiving signals from
the
sense electrodes 204 in frames during touch detection scanning. The drive
electrodes 202 may be driven with a predetermined number of pulses in a frame.
For example, each drive electrode 202 may be driven with 4 pulses when noise
is
not detected or when the detected noise does not meet a threshold value. Noise
detection is performed 304 during touch detection by receiving signals from
the
noise-detection electrode 206 and comparing the signals from the noise-
detection
electrode 206 to a baseline value. The baseline value may be a set value or
may be
a value determined based on signals previously received from the noise-
detection
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electrode 206. For example, the amplitude of the signal from the noise-
detection
electrode 206 may be compared to a baseline amplitude value. When the
difference between the signal value and the baseline value meets a threshold,
a
noisy condition is detected. Alternatively, a noisy condition may be detected
when
the signal received from the noise-detection electrode 206 meets a threshold
value.
Noise detection may be performed while one or more of the drive electrodes 202
are driven.
[0034] In response to detecting 306 a noisy condition, at least one touch-
detection parameter is changed 308 to reduce the effect of noise on touch
detection.
[0035] A front view of another example of an electronic device 100 is shown in
FIG. 4. Drive electrodes 402, sense electrodes 404, and a noise-detection
electrode
406 are shown for the purpose of illustration, but are not visible to the eye
when
looking at the front of the electronic device 100.
[0036] In the example of FIG. 4, the drive electrodes 402 include three
generally
horizontal detection lines 408 that are joined together at one end 410. The
sense
electrodes 406 include two generally vertical detection lines 412 that are
joined at
the ends 414. Other shapes of drive and sense electrodes may successfully be
implemented. Alternatively, the drive electrodes may extend generally
vertically
and the sense electrodes may extend generally horizontally.
[0037] A method includes performing touch detection on a touch-sensitive
display
of an electronic device by driving drive electrodes at a first frequency while
sensing
utilizing sense electrodes to obtain touch data, and filtering the touch data
to
identify touches. The method includes detecting noise based on signals from a
noise-detection electrode that is spaced from the drive electrodes and the
sense
electrodes, wherein noise is detected while driving at least one of the drive
electrodes, and in response to detecting noise that meets a threshold,
altering at
least one touch detection parameter to reduce the effect of noise.
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[0038] Noise may be detected when no touch detection is performed. Noise may
also be detected while drive electrodes are driven to detect touches. A
separate
frame or frames of the scan are not required for noise detection.
Additionally, noise
may be detected during any number of frames of the scan. For example, noise
may
be detected during all of the frames of the scan. In response to detecting a
noisy
condition, touch detection may be altered to reduce the effect of noise on
touch
detection.
[0039] The present disclosure may be embodied in other specific forms without
departing from its spirit or essential characteristics. The described
embodiments
are to be considered in all respects only as illustrative and not restrictive.
The
scope of the disclosure is, therefore, indicated by the appended claims rather
than
by the foregoing description. All changes that come within the meaning and
range
of equivalency of the claims are to be embraced within their scope.
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