U.S. patent application number 17/742362 was filed with the patent office on 2022-08-25 for display device and driving method thereof.
This patent application is currently assigned to InnoLux Corporation. The applicant listed for this patent is InnoLux Corporation. Invention is credited to Kuan-Feng LEE, Chandra LIUS.
Application Number | 20220270557 17/742362 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220270557 |
Kind Code |
A1 |
LIUS; Chandra ; et
al. |
August 25, 2022 |
DISPLAY DEVICE AND DRIVING METHOD THEREOF
Abstract
The present disclosure provides a display device including a
controlling unit, a display driver, a sensor driver, a display
element, and a sensor element. The display driver and the sensor
driver are electrically connected to the controlling unit
respectively. The display element is electrically connected to the
display driver, and the sensor element is electrically connected to
the sensor driver. The sensor element is sensing a biometric
feature in a sensing time period, and the sensing time period
comprises 3 to 120 frame times. The display element is refreshed
one time in each of the 3 to 120 frame times by the display driver,
the sensor element is capable of receiving light emitted from the
display element 3 to 120 times in the sensing time period, and the
sensor driver receives a plurality of readout signals from the
sensor element in an ending portion of the sensing time period.
Inventors: |
LIUS; Chandra; (Miao-Li
County, TW) ; LEE; Kuan-Feng; (Miao-Li County,
TW) |
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Applicant: |
Name |
City |
State |
Country |
Type |
InnoLux Corporation |
Miao-Li County |
|
TW |
|
|
Assignee: |
InnoLux Corporation
Miao-Li County
TW
|
Appl. No.: |
17/742362 |
Filed: |
May 11, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16416263 |
May 19, 2019 |
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17742362 |
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International
Class: |
G09G 3/36 20060101
G09G003/36; G09G 3/20 20060101 G09G003/20; G06V 40/13 20060101
G06V040/13 |
Claims
1. A display device, comprising: a controlling unit; a display
driver electrically connected to the controlling unit; a sensor
driver electrically connected to the controlling unit; a display
element electrically connected to the display driver; and a sensor
element electrically connected to the sensor driver; wherein the
sensor element is sensing a biometric feature in a sensing time
period, the sensing time period comprises 3 to 120 frame times, the
display element is refreshed one time in each of the 3 to 120 frame
times by the display driver, the sensor element is capable of
receiving light emitted from the display element 3 to 120 times in
the sensing time period, and the sensor driver receives a plurality
of readout signals from the sensor element in an ending portion of
the sensing time period.
2. The display device according to claim 1, wherein the display
element is refreshed by the display driver 6 to 72 times in the
sensing time period.
3. The display device according to claim 1, wherein the sensor
element is refreshed at least one time in the sensing time
period.
4. The display device according to claim 1, wherein the display
element comprises a plurality of sub-pixels having a same color,
and all the plurality of sub-pixels are turned on repeatedly in the
sensing time period.
5. The display device according to claim 1, wherein the display
element comprises a plurality of sub-pixels, and a first group of
the plurality of sub-pixels and a second group of the plurality of
sub-pixels are turned on sequentially.
6. The display device according to claim 5, wherein the first group
of the plurality of sub-pixels and the second group of the
plurality of sub-pixels have a same color.
7. The display device according to claim 5, wherein the first group
of the plurality of sub-pixels have a first color, and the second
group of the plurality of sub-pixels have a second color different
from the first color.
8. The display device according to claim 7, wherein a third group
of the plurality of sub-pixels having the first color, and the
first group of the plurality of sub-pixels, the second group of the
plurality of sub-pixels, the third group of the plurality of
sub-pixels and the second group of the plurality of sub-pixels are
turned on alternately.
9. The display device according to claim 1, wherein the display
element comprises a plurality of sub-pixels, a first group of the
plurality of sub-pixels has a first color and a second group of the
plurality of sub-pixels has a second color different from the first
color, and the first group of the plurality of sub-pixels and the
second group of the plurality of sub-pixels are turned on at a same
time.
10. The display device according to claim 9, wherein a third group
of the plurality of sub-pixels has the first color, and the first
group of the plurality of sub-pixels and the third group of the
plurality of sub-pixels are turned on sequentially.
11. The display device according to claim 1, wherein the sensor
driver is activated by an enable signal from the controlling
unit.
12. The display device according to claim 1, wherein the display
driver and the sensor driver are synchronized by the controlling
unit.
13. The display device according to claim 1, further comprising a
processing unit, wherein the processing unit is electrically
connected to the controlling unit, the display driver, and the
sensor driver respectively, and the processing unit, the display
driver and the sensor driver are integrated in a single integrated
circuit.
14. The display device according to claim 1, wherein the display
element comprises a first sub-pixel having a first color and a
second sub-pixel having a second color different from the first
color, the sensor element comprises a sensing unit disposed between
the first sub-pixel and the second sub-pixel, and a distance
between the sensing unit and the first sub-pixel is less than a
distance between the sensing unit and the second sub-pixel.
15. The display device according to claim 1, wherein in one of the
3 to 120 frame times, one of sub-pixels of the display element
emits a light pulse one time.
16. The display device according to claim 1, wherein the display
element comprises a plurality of light-emitting units, and the
sensor element is disposed under the plurality of light-emitting
units.
17. The display device according to claim 1, further comprising a
liquid crystal layer disposed between the display element and the
sensor element.
18. A driving method of a display device, comprising: providing a
display control signal to a display driver and a sensor control
signal to a sensor driver by a controlling unit; transmitting a
display driving signal to a display element by the display driver;
and transmitting a sensor driving signal to a sensor element by the
sensor driver, wherein the sensor element is sensing a biometric
feature in a sensing time period, the sensing time period comprises
3 to 120 frame times of the display element, the display element is
refreshed one time in each of the 3 to 120 frame times by the
display driver, the sensor element is capable of receiving light
emitted from the display element 3 to 120 times in the sensing time
period, and the sensor driver receives a plurality of readout
signals from the sensor element in an ending portion of the sensing
time period.
19. The driving method of the display device according to claim 18,
wherein the display element is refreshed by the display driver 6 to
72 times in the sensing time period.
20. The driving method of the display device according to claim 18,
wherein in one of the 3 to 120 frame times, one of sub-pixels of
the display element emits a light pulse one time.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 16/416,263, filed on May 19, 2019. The content
of the application is incorporated herein by reference.
BACKGROUND OF THE DISCLOSURE
1. Field of the Disclosure
[0002] The present disclosure relates to a display device and a
driving method thereof, and more particularly, to a display device
having biometric sensors and a driving method thereof.
2. Description of the Prior Art
[0003] The growing demand for information security and information
privacy has driven use of biometric authentication on electronic
devices such as smartphones, laptops, tablets, banking devices, and
gaming consoles. A popular form of biometric authentication is
fingerprint identification. Recently, fingerprint sensors have been
adopted by various electronic devices so that the electronic
devices can be unlocked by device owners via fingerprint
authentication, protecting the electronic devices from unauthorized
access.
[0004] Conventionally, just for an example, a fingerprint sensor is
provided separately from a display panel in a display device, so a
screen-locked display device can be unlocked by simply touching the
fingerprint sensor. Nevertheless, it is of great interest to
display device manufacturers and users to combine the fingerprint
sensor into the display panel, thereby increasing the
screen-to-body ratio of the display device and offering a
narrow-border or bezel-less design. However, it is difficult to add
the fingerprint sensor into the display region without losing the
resolution of the display device, and when the fingerprint sensor
is disposed in the display region, the area of the fingerprint
sensor will be too small, resulting in bad sensitivity.
SUMMARY OF THE DISCLOSURE
[0005] According to an embodiment, a display device is disclosed
and includes a controlling unit, a display driver electrically
connected to the controlling unit, a sensor driver electrically
connected to the controlling unit, a display element electrically
connected to the display driver, and a sensor element electrically
connected to the sensor driver. The sensor element is sensing a
biometric feature in a sensing time period, and the sensing time
period comprises 3 to 120 frame times. The display element is
refreshed one time in each of the 3 to 120 frame times by the
display driver, the sensor element is capable of receiving light
emitted from the display element 3 to 120 times in the sensing time
period, and the sensor driver receives a plurality of readout
signals from the sensor element in an ending portion of the sensing
time period.
[0006] According to another embodiment, a driving method of a
display device is disclosed and includes the following steps.
First, a display control signal is provided to a display driver and
a sensor control signal is provided to a sensor driver by a
controlling unit. Next, a display driving signal is transmitted to
a display element by the display driver. Then, a sensor driving
signal is transmitted to a sensor element by the sensor driver,
wherein the sensor element is sensing a biometric feature in a
sensing time period, and the sensing time period comprises 3 to 120
frame times. The display element is refreshed one time in each of
the 3 to 120 frame times by the display driver, the sensor element
is capable of receiving light emitted from the display element 3 to
120 times in the sensing time period, and the sensor driver
receives a plurality of readout signals from the sensor element in
an ending portion of the sensing time period.
[0007] These and other objectives of the present disclosure will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the embodiment that
is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 schematically illustrates a block diagram of a
display device according to an embodiment of the present
disclosure.
[0009] FIG. 2 schematically illustrates a top view of a display
device according to this embodiment of the present disclosure.
[0010] FIG. 3 and FIG. 4 schematically illustrate sectional views
of display elements and sensor elements according to some
embodiments of the present disclosure.
[0011] FIG. 5 schematically illustrates a top view of an
arrangement of the sub-pixels and the sensing units according to
some embodiments of the present disclosure.
[0012] FIG. 6 schematically illustrates a flowchart of a driving
method of the display device for identifying the biometric feature
according to this embodiment of the present disclosure.
[0013] FIG. 7 schematically illustrates timing sequences of the
display control signal, the sensor control signal, the display
scanning signal, the sensor scanning signal and the readout
signal.
[0014] FIG. 8 schematically illustrates the sub-pixels turned on in
different frame times according to some embodiments of the present
disclosure.
[0015] FIG. 9 schematically illustrates sub-pixels turned on in
different frame times according to some embodiments of the present
disclosure.
[0016] FIG. 10 schematically illustrates the sub-pixels turned on
in different frame times according to some embodiments of the
present disclosure.
[0017] FIG. 11 schematically illustrates the sub-pixels turned on
in different frame times according to some embodiments of the
present disclosure.
DETAILED DESCRIPTION
[0018] The present disclosure may be understood by reference to the
following detailed description, taken in conjunction with the
drawings as described below. It is noted that, for purposes of
illustrative clarity and being easily understood by the readers,
various drawings of this disclosure show a portion of the
electronic device, and certain elements in various drawings may not
be drawn to scale. In addition, the number and dimension of each
element shown in drawings are only illustrative and are not
intended to limit the scope of the present disclosure.
[0019] Certain terms are used throughout the description and
following claims to refer to particular elements. As one skilled in
the art will understand, electronic equipment manufacturers may
refer to an element by different names. This document does not
intend to distinguish between elements that differ in name but not
function. In the following description and in the claims, the terms
"include", "comprise" and "have" are used in an open-ended fashion,
and thus should be interpreted to mean "include, but not limited to
. . . ".
[0020] It will be understood that when an element or layer is
referred to as being "disposed on" or "connected to" another
element or layer, it can be directly on or directly connected to
the other element or layer, or intervening elements or layers may
be presented (indirectly). In contrast, when an element is referred
to as being "directly on" or "directly connected to" another
element or layer, there are no intervening elements or layers
presented.
[0021] In addition, in this specification, relative expressions may
be used. For example, "lower", "bottom", "higher" or "top" are used
to describe the position of one element relative to another.
[0022] Although terms such as first, second, third, etc., maybe
used to describe diverse constituent elements, such constituent
elements are not limited by the terms. The terms are used only to
discriminate a constituent element from other constituent elements
in the specification. The claims may not use the same terms, but
instead may use the terms first, second, third, etc. with respect
to the order in which an element is claimed. Accordingly, in the
following description, a first constituent element may be a second
constituent element in a claim.
[0023] As used herein, the term "connected to" or "coupled to" that
is used to designate a connection or coupling of one element to
another element includes both a case that an element is "directly
connected or coupled to" another element and a case that an element
is "electronically connected or coupled to" another element via
still another element.
[0024] It should be noted that the technical features in different
embodiments described in the following can be replaced, recombined,
or mixed with one another to constitute another embodiment without
departing from the spirit of the present disclosure.
[0025] FIG. 1 schematically illustrates a block diagram of a
display device according to an embodiment of the present
disclosure. The display device 1 can both display image and
identify biometric feature in its display region. For example, the
display device 1 may be a smartwatch, a smartphone, a tablet or a
display device having an in-display biometric sensor, but not
limited thereto. In another embodiment, the display device 1 also
could be used for tiling another display device to form a tiling
electronic device. As shown in FIG. 1, the display device 1 of this
embodiment includes a controlling unit 10, a display driver 12, a
sensor driver 14, a display element 16, and a sensor element 18.
The display driver 12 and the sensor driver 14 are electrically
connected to the controlling unit 10 respectively, so the
controlling unit 10 can respectively provide a display control
signal DC to the display driver 12 and provide a sensor control
signal SC to the sensor driver 14 for separately controlling on/off
state of the display driver 12 and on/off state of the sensor
driver 14. The controlling unit 10 may be for example an image
processor, a digital signal processor, a central processing unit
(CPU), a microprocessor or other suitable device. Furthermore, the
display element 16 is electrically connected to and driven by the
display driver 12, and the sensor element 18 is electrically
connected to and driven by the sensor driver 14. After receiving
the display control signal DC, the display driver 12 can transmit a
display driving signal DDS to the display element 16 to turn on the
display element 16; similarly, after receiving the sensor control
signal SC, the sensor driver 14 can transmit a sensor driving
signal SDS to the sensor element 18 to turn on the sensor element
18. The display element 16 is used for displaying image on screen
or generating light for biometric feature identification; for
example, the display element 16 may include sub-pixels of
self-emissive display panel, such as an organic light-emitting
diode (OLED) display panel, or an inorganic LED (such as
quantum-dot LED, Mini-LED, or Micro-LED) display panel, or
sub-pixels of non-self-emissive display panel, such as a liquid
crystal display panel. The sensor element 18 is used for receiving
reflected light from the biometric feature, so as to capture
information (such as an image) of the biometric feature. The sensor
element 18 may be for example a fingerprint sensor or other kind of
image sensor, but not limited thereto.
[0026] In this embodiment, the display device 1 may optionally
further include a processing unit 24, and the controlling unit 10
is electrically connected to the display driver 12 and the sensor
driver 14 through the processing unit 24. The function of the
processing unit 24 may be the same as or similar to the function of
the controlling unit 10, but not limited thereto. For example, the
processing unit 24 can drive or operate the display driver 12 and
drive the sensor driver 14, and then read signals from the sensor
element 18 out. In such case, the controlling unit 10 may not only
be used to drive the display driver 12, the sensor driver 14, the
display element 16 and the sensor element 18, but also other
devices. Thus, when the area of the display element 16 and the
sensor element 18 is large, the data needed to process is huge,
which may reduce the signal processing speed of the controlling
unit 10. By means of the processing unit 24 designed to process
signals in advance, the load of the controlling unit 10 can be
shared with the processing unit 24. The signal processing speed of
the display device 1 may be enhanced accordingly. In such
situation, the display control signal DC and the sensor control
signal SC may be provided from the processing unit 24. In some
embodiment, the display driver 12, the sensor driver 14 and the
processing unit 24 may be integrated into a single integrated
circuit 25 that may be bonded on an array substrate of the display
device 1, and the display element 16 and the sensor element 18 may
be electrically connected to the single integrated circuit 25
through wires, but not limited thereto. In some embodiments, the
display device 1 may not include the processing unit 24.
[0027] The display driver 12 may include a gate driver 121 and a
data driver 122 for driving the display element 16. The gate driver
121 may provide scanning signals for turning on the display element
16, and the data driver 122 may provide display signals to the
display element 16, such that the display element 16 can display
the desired image. For example, the gate driver 121 may include
shift register unit, logic unit, level shift unit and/or digital
buffer unit, and the data driver 122 may include shift register
unit, level shift unit, digital to analog converter (or
multiplexer) and/or analog buffer unit, but not limited thereto.
The sensor driver 14 may include another gate driver 141 and a
readout driver 142 for signal readout of the sensor element 18. The
gate driver 141 may provide scanning signals for turning on the
sensor element 18, and the readout driver 142 may receive readout
signals from the sensor element 18, such that the signals detected
by the sensor element 18 can be read out. In some embodiments, the
gate driver 121, the data driver 122, the gate driver 141 and/or
the readout driver 142 may be formed in the array substrate of the
display device 1 by thin-film transistor process, but not limited
thereto. In some embodiments, the gate driver 121, data driver 122,
the gate driver 141 and/or the readout driver 142 may be formed in
one or more integrated circuit and be bonded on the array substrate
or a flexible printed circuit substrate that adheres to the array
substrate.
[0028] In this embodiment, the display driver 12 may optionally
further include a timing control unit 123 electrically connected to
the gate driver 121 and the data driver 122 to provide timing
signals to the gate driver 121 and the data driver 122
respectively, and the gate driver 121 and the data driver 122 are
electrically connected to the controlling unit 10 or the processing
unit 24 through the timing control unit 123. In some embodiments,
the timing control unit 123 may be disposed outside the display
driver 12 but still be electrically connected between the gate
driver 121 and the controlling unit 10 or the processing unit 24
and between the data driver 122 and the controlling unit 10 or the
processing unit 24.
[0029] In this embodiment, the sensor driver 14 may optionally
further include another timing control unit 143 electrically
connected to the gate driver 141 and the readout driver 142 to
provide timing signals to the gate driver 141 and the readout
driver 142 respectively, and the gate driver 141 and the readout
driver 142 are electrically connected to the controlling unit 10 or
the processing unit 24 through the another timing control unit 143.
In some embodiments, the another timing control unit 143 may be
disposed outside the sensor driver 14 but still be electrically
connected between the gate driver 141 and the controlling unit 10
or the processing unit 24 and between the readout driver 142 and
the controlling unit 10 or the processing unit 24.
[0030] In some embodiments, the timing control unit 123 and the
another timing control unit 143 may be integrated into one timing
control unit outside the display driver 12 and the sensor driver
14, and the integrated timing control unit may electrically connect
the display driver 12 and the sensor driver 14 to the controlling
unit 10 or the processing unit 24 respectively, thereby reducing
the number of the timing control units. Since the display driver 12
and the sensor driver 14 are controlled by the same one timing
control unit, the possibility of timing disorder or timing error
can be reduced. Also, when the processing unit 24, the integrated
one timing control unit, the display driver 12 and the sensor
driver 14 are integrated into one integrated circuit, the size of
the integrated circuit can be decreased, and the border width of
the display device 1 for disposing the integrated circuit can be
narrowed. In some embodiments, the integrated one timing
controlling unit and the processing unit 24 may be integrated into
a single integrated circuit while the display driver 12 and the
sensor driver 14 are not integrated into the single integrated
circuit.
[0031] In some embodiments, the display device 1 may further
include a touch sensing element (not shown in figures) for sensing
the position of the biometric feature. The touch sensing element
may be electrically connected to the controlling unit 10 or the
processing unit 24, such that when the touch sensing element senses
the touching of the biometric feature on the display device 1, the
controlling unit 10 or the processing unit 24 may define the
touching region of the biometric feature as a biometric feature
identifying region for further detecting the biometric feature.
[0032] FIG. 2 schematically illustrates a top view of a display
device according to this embodiment of the present disclosure. The
display device 1 has a display region 1D for displaying image and a
peripheral region 1P that doesn't display image. The peripheral
region 1P is disposed on at least one side of the display region
1D. For example, the peripheral region 1P surrounds the display
region 1D. A width of the peripheral region 1P may be also referred
to as the border width of the display decide 1. The display element
16 and the sensor element 18 are disposed in the display region 1D,
and the display driver 12, the sensor driver 14 and the processing
unit 24 shown in FIG. 1 are disposed in the peripheral region 1P.
The regions and the numbers of the gate driver 121 and the data
driver 122 of display driver 12 and the regions and numbers of the
gate driver 141 and the readout driver 142 of the sensor driver 14
shown in FIG. 2 are for illustration and not limited thereto. In
some embodiments, the number of the gate driver 121 and/or the
number of the data driver 122 may be one or more. In some
embodiments, the number of the gate driver 141 and/or the number of
the readout driver 142 may be one or more.
[0033] Specifically, the display device 1 may further include a
plurality of display scan lines 26, a plurality of display data
lines 28, a plurality of sensor scan lines 30, and a plurality of
sensor signal lines 32 formed on a substrate Sub. The display
element 16 includes a plurality of sub-pixels 161 and a plurality
of transistors 162 formed on the substrate Sub, in which each
sub-pixel 161 is electrically connected to a corresponding
transistor 162, and a gate and a source of each transistor 162 are
electrically connected to the gate driver 121 and the data driver
122 respectively through a corresponding display scan line 26 and a
corresponding display data line 28, such that the on/off state of
each transistor 162 can be controlled by display scanning signals
DS1-DSN from the gate driver 121, and the display of each sub-pixel
161 can be controlled by display data signals DD1-DDN from the data
driver 122. In one embodiment, the display element 16 may include
at least one transistor 162 corresponding to one of the sub-pixels
161, for example, if the display element 16 includes at least two
transistors 162 corresponding to one of the sub-pixels 161, wherein
the at least two transistors 162 could be of a same type or
different types, but not limited thereto. In an example of the
transistor of the display element 16 electrically connected to the
corresponding sub-pixel 161, the number of the transistor
corresponding to one of the sub-pixels may be 1, 3, 4 or 7. In
another example of the display element 16 including plural
transistors 162 corresponding to one sub-pixel 161, the plural
transistors 162 may include a switch transistor and/or a driving
transistor, but not limited thereto. In some embodiments, the
transistor 162 "corresponding to" one of the sub-pixels as used
herein represents the transistor 162 is electrically connected to
the one of the sub-pixels 161.
[0034] Similarly, the sensor element 18 includes a plurality of
sensing units 181 and a plurality of transistors 182 formed on the
substrate Sub, in which each sensing unit 181 is electrically
connected to a corresponding transistor 182, and a gate and a
source of each transistor 182 are electrically connected to the
gate driver 141 and the driver 142 respectively through a
corresponding sensor scan line 30 and a corresponding sensor signal
line 32, such that the on/off state of each transistor 182 can be
controlled by sensor scanning signals SS1-SSN from the gate driver
141, and the readout driver 142 may receive readout signals RS1-RSN
from each sensing unit 181. In addition, the sensor element 18 may
include at least one transistor 182 corresponding to one of the
sensing units 181. In another example of the transistor of the
sensor element 18 electrically connected to the corresponding
sensing unit 181, the number of the transistor may be 2 or 3. In
another example of the sensor element 18 including plural
transistors 182 corresponding to one sensing unit 181, the plural
transistors 182 may include a readout transistor, a reset
transistor and/or an amplifier transistor but not limited thereto.
The transistor 182 "corresponding to" one of the sensing units 181
as used herein represents the transistor 182 is electrically
connected to the one of the sensing units 181. In some embodiments,
the transistor 162 and/or the transistor 182 may be a thin-film
transistor. In some embodiments, type of the transistor 162 and/or
the transistor 182 may be an amorphous thin-film transistor, a
low-temperature polysilicon thin-film transistor, a metal-oxide
thin-film transistor, but it is not limited thereto.
[0035] In this embodiment, each sensing unit 181 is used to detect
light from the corresponding sub-pixel 161. For example, the
sensing units 181 may include a plurality of sensing units 181a, a
plurality of sensing units 181b, and a plurality of sensing units
181c, the sub-pixels 161 may include a plurality of first sub-pixel
161a for emitting light with a first color, a plurality of second
sub-pixel 161b for emitting light with a second color, and a
plurality of third sub-pixel 161c for emitting light with a third
color, and each sensing unit 181a, each sensing unit 181b and each
sensing unit 181c correspond to one first sub-pixel 161a, one
second sub-pixel 161b and one third sub-pixel 161c respectively. In
other words, each sensing unit 181a can detect the light having the
first color, each sensing unit 181b can detect the light having the
second color, and each sensing unit 181c can detect the light
having the third color, in which the first color, the second color
and the third color are different from one another, but not limited
thereto. For example, the first color, the second color and the
third color may be respectively red, green and blue, but not
limited thereto. For example, the sensing unit 181 may include a
corresponding color filter disposed thereon for allowing one color
passing through and filtering light with different colors so as to
avoid light interference. In some embodiments, each sensing unit
181 may for example be an optical (such as photo diode) detector, a
capacitive detector, a radio frequency (RF) detector, a thermal,
piezoresistive detector, an ultrasonic detector, or a piezoelectric
detector, but not limited thereto.
[0036] FIG. 3 and FIG. 4 schematically illustrate sectional views
of display devices according to some embodiments of the present
disclosure. In some embodiments shown in FIG. 3, the display device
1A may include self-emissive display panel, and each of the
sub-pixels 161 of the display element 16A may include a
light-emitting unit LU. Specifically, the display device 1A may
include a display layer 34A formed on the substrate Sub and a cover
substrate 36 covering and protecting the display layer 34A, in
which the display layer 34A may include the light-emitting units LU
of the display element 16A and the sensor element 18 including a
plurality of sensing units 181, and the sensor element 18 may be
formed under the light-emitting units LU, but not limited thereto.
For example, the sensor element 18 is disposed between the
light-emitting units LU and the substrate Sub, i.e. the
light-emitting units LU and the sensor element 18 are formed in the
same display layer 34A. In a vertical direction VD(top view), the
sensing units 181 may be disposed in the gaps of the sub-pixels
161, such that the light from the sub-pixel 161 can be reflected to
the corresponding sensing unit 181 by the biometric feature 38, as
an arrow shown in FIG. 3. The vertical direction VD is defined as
being substantially perpendicular to a horizontal direction HD. The
horizontal direction HD represents the horizontal direction of the
substrate Sub that is flattened horizontally. In some embodiments,
the light-emitting unit LU may include organic light-emitting diode
(OLED), quantum-dot LED (QLED), Mini-LED, Micro-LED or other type
light-emitting device. In some embodiments, the sensing units 181
may be formed under the substrate Sub, so that the sub-pixels 161
and the sensing units 181 are formed on two sides of the substrate
Sub (not shown in FIG. 3).
[0037] In some embodiments shown in FIG. 4, the display device 1B
may include non-self-emissive display panel. For example, the
non-self-emissive display panel is a liquid crystal display panel,
and the display layer 34B of the display device 1B may include a
liquid crystal layer LC, the display element 16B and the sensor
element 18 between the substrate Sub and a counter substrate 40, in
which the liquid crystal layer LC is disposed between the display
element 16B and the sensor element 18. Specifically, the display
element 16B is disposed between the liquid crystal layer LC and the
substrate Sub, the sensor element 18 is disposed between the liquid
crystal layer LC and a counter substrate 40, and the sensing unit
181 is disposed above the corresponding transistor (e.g. transistor
162) of the display element 16B. Also, the display device 1B may
further include a backlight module BLU disposed under the substrate
Sub and used for generating a suitable light (such as white light).
The sub-pixel 161 of some embodiments may include a liquid crystal
controller 1611 for controlling the rotation of the liquid crystal
molecules corresponding to the region of the sub-pixel 161. For
example, the liquid crystal controller 1611 may be a pixel
electrode or other components, but not limited thereto. Thus, light
from backlight module BLU can penetrate through the sub-pixel 161
and be reflected by the biometric feature to the corresponding
sensing unit 181, as an arrow shown in FIG. 4. For example, the
counter substrate 40 may include color filters (not shown) for
allowing light having different colors to be emitted. In some
embodiments, in order to generate light with uniform brightness,
the color filters with different colors may have different
thicknesses. In some embodiments, the display device 1B may
optionally include the cover substrate 36 disposed on the counter
substrate 40. In some embodiments, the sensor element 18 may be
disposed between the counter substrate 40 and the cover substrate
36. In one embodiment, the cover substrate 36 can have a touch
function, but not limited thereto.
[0038] FIG. 5 schematically illustrates a top view of an
arrangement of the sub-pixels and the sensing units according to
some embodiments of the present disclosure. In some embodiments,
the arrangement of the sub-pixels 161 may be pentile matrix, and
each sensing unit 181 is disposed between adjacent two of
sub-pixels 161. For example, in an odd row, the first sub-pixels
161a having first color and the third sub-pixels 161c having third
color are alternately arranged along the row direction, and the
sensing units 181 and the sub-pixels 161 (such as 161a and 161c) in
the odd row are alternately arranged along the row direction. In an
even row, the second sub-pixels 161b having second color are
arranged along the row direction, and the sub-pixels 161 (such as
161b) and the sensing units 181 in the even row are alternately
arranged along the row direction. Also, in an odd column, the
second sub-pixels 161b and the sensing units 181 are alternately
arranged along the column direction; and in an even column, the
first sub-pixels 161a and the third sub-pixels 161c are alternately
arranged along the column direction, and the sub-pixels 161 (such
as 161a and 161c) and the sensing units 181 in the odd column are
alternately arranged along the column direction.
[0039] In some embodiments, the first sub-pixel 161a, the second
sub-pixel 161b and the third sub-pixel 161c may have different
areas in a top view of the display device 1. For example, since the
first color, the second color and the third color are red, green
and blue respectively, the area of the third sub-pixel 161c may be
greater than the area of the first sub-pixel 161a, and the area of
the first sub-pixel 161a may be greater than the area of the second
sub-pixel 161b. In some embodiments, the sensing units 181 may have
different areas in a top view of the display device 1 based on the
area difference between the sub-pixels 161. For example, the
sensing units 181 arranged in the same row as the first sub-pixels
161a and the third sub-pixels 161c (such as odd row) may have
greater area or less area than the sensing units 181 arranged in
the same row as the second sub-pixels 161b (such as even row). In
some embodiments, one of the sensing units 181 between the adjacent
first sub-pixel 161a and the adjacent third sub-pixel 161c may be
closer to the adjacent first sub-pixel 161a having the first color
than the adjacent third sub-pixel 161c having the third color. In
other words, since third sub-pixel 161c emits blue light, which is
scattered easier and worse than the red light, to improve the
signal to noise ratio (S/N) of the sensor element 18, a distance W1
between the sensing unit 181 and the adjacent first sub-pixel 161a
is less than a distance W2 between the sensing unit 181 and the
adjacent third sub-pixel 161c. The distance W1 is the shortest
distance between the sensing unit 181 and the first sub-pixel 161a
adjacent to each other in a row direction RD, and the distance W2
is the shortest distance between the sensing unit 181 and the third
sub-pixel 161c adjacent to each other in the row direction RD. In
some embodiments, any two of the colors of the first sub-pixel
161a, the second sub-pixel 161b and the third sub-pixel 161c may be
exchanged or may be other colors. In some embodiments, arrangement
of the first sub-pixel 161a, the second sub-pixel 161b and the
third sub-pixel 161c may be other kind of arrangement.
[0040] The following description further details a driving method
of the display device of the present disclosure. FIG. 6
schematically illustrates a flowchart of a driving method of the
display device for identifying the biometric feature according to
this embodiment of the present disclosure, and FIG. 7 schematically
illustrates timing sequences of the display control signal, the
sensor control signal, the display scanning signal, the sensor
scanning signal and the readout signal. The driving method of the
display device includes the following steps and is detailed
accompanying with FIG. 7 as well as FIG. 1 and FIG. 2. In step
S102, the display device 1 starts a sensing time period SP. In the
sensing time period SP, the display device 1 starts to detect the
biometric feature. For example, when the sensor element 18 detects
the touching of the biometric feature on the display device 1, the
controlling unit 10 or the processing unit 24 may start the sensing
time period SP for detecting the biometric feature. The condition
for starting the sensing time period SP of the present disclosure
is not limited thereto.
[0041] In step S104, the display control signal DC and the sensor
control signal SC (an enable signal) are respectively provided to
the display driver 12 and the sensor driver 14 by the control unit
10 or the processing unit 24, such that the sensor driver 14 can be
activated by the enable signal from the control unit 10 or the
processing unit 24. The duration of the display control signal DC
overlaps the duration of the sensor control signal SC, such that
the display element 16 may generate light for biometric feature
identification and the sensor element 18 can detect the reflected
light from the biometric feature. For example, the display control
signal DC and the sensor control signal SC may be simultaneously
provided by the controlling unit 10 or the processing unit 24 and
be ended at the same time, such that the display driver 12 and the
sensor driver 14 can be synchronized by the controlling unit 10 or
the processing unit 24. In some embodiments, the start time ST1 of
the display control signal DC may be earlier than the start time
ST2 of sensor control signal SC. As long as the biometric feature
can be correctly identified, the start time ST1 and the end time
ET1 of the display control signal DC and the start time ST2 and the
end time ET2 of the sensor control signal SC can be altered.
[0042] In step S106, after the display driver 12 receives the
display control signal DC, a display driving signal DDS is
transmitted to a display element 16 by the display driver 12, and
the display element 16 is refreshed a first predetermined number of
times when the sensing element 18 is sensing the biometric feature
in the sensing time period SP. In this embodiment, the first
predetermined number of times may range from 3 to 120 in the
sensing time period SP. In other words, the display driving signal
DDS may be repeatedly transmitted to the display element 16 ranged
from 3 to 120 times, such that the sub-pixels 161 may generate
light pulse 3 to 120 times. It is noted that since the display
element 16 can generate light pulse 3 to 120 times in the sensing
time period SP, the sensor element 18 can receive light 3 to 120
times, thereby accumulating enough electric charges and improving
the S/N ratio and the sensitivity of the sensing units. For this
reason, the sensing units 181 can be disposed in the display region
1D without reducing the area of each sub-pixel 161 or reducing the
resolution of the display device 1, i.e. the sensor element 18 can
be integrated with the display element 16 into the display region
1D of the display device 1, thereby increasing screen-to-body ratio
while providing biometric authentication. Also, even the area of
the sensing unit 181 is small, through the increased refreshing
times, the sensing units 181 still can have good sensitivity.
[0043] Specifically, the display driving signal DDS may include a
plurality of display scanning signals DS1-DSN transmitted to the
display scan line 26 respectively and a plurality of display data
signals DD1-DDN transmitted to the display data lines 28
respectively. In one frame time FT of the sensing time period SP,
the display scanning signals DS1-DSN may be sequentially
transmitted one time, and the display data signals DD1-DDN may be
transmitted according to the display scanning signals DS1-DSN, such
that the sub-pixels 161 can emit the required light pulse one time
while receiving the display data signals DD1-DDN. When the display
element 16 is refreshed 3 to 120 times in the sensing time period
SP, the display scanning signals DS1-DSN may be sequentially
transmitted to the display element 16 ranged from 3 to 120 times in
3 to 120 frame times FT. In some embodiments, adjacent two of the
display scanning signals DS1-DSN may overlap each other or not in
one frame time FT. In some embodiment, the first predetermined
number of times may be 6 to 72 times. In order to have short
unlocking time, the first predetermined number of times may be
decreased based on the frame time FT. For example, when the
refreshing rate(frequency) of the display device 1 is 60 Hz (i.e.
the frame time FT is 0.0167 seconds, the first predetermined number
of times may be 6, 18 or 30. When the refreshing rate(frequency) of
the display device 1 is 120 Hz (i.e. the frame time FT is 0.0083
seconds less than 0.0167 seconds), the first predetermined number
of times may be increased to be 12, 36 or 60.
[0044] In step S108, after the sensor driver 14 receives the sensor
control signal SC, a sensor driving signal SDS is transmitted to
the sensor element 18 by the sensor driver 14, and the sensor
element 18 is refreshed a second predetermined number of times in
the sensing time period SP. In this embodiment, as shown in FIG. 7,
the second predetermined number of times may be one. Specifically,
the sensor driving signal SDS may include a plurality of sensor
scanning signals SS1-SSN and a plurality of readout signals
RS1-RSN. When the sensor element 18 is driven once, the duration of
the sensor scanning signals SS1-SSN may overlap all the frame times
FT of the display element 16. The readout signals RS1-RSN may be
received by the readout driver 142 near the end time of the sensor
scanning signals SS1-SSN. The duration of the readout signals
RS1-RSN may overlap at least one frame time FT or not. In some
embodiments, the second predetermined number of times may be
plural, so the electric charges converted by the sensing units 181
can be read out plural times in one sensing time period SP by the
readout driver 142, and the readout signals RS1-RSN received by the
readout driver 142 more than one times in one sensing time period
SP can be accumulated by the sensor driver 14 to increase the S/N
ratio. In some embodiments, the sensor element 18 of the display
device 1 may perform more than one times to detect the biometric
feature in more than one sensing time periods SP.
[0045] FIG. 8 schematically illustrates the sub-pixels turned on in
different frame times according to some embodiments of the present
disclosure. For clarity, the arrangement of the sub-pixels
mentioned in the following embodiments takes pentile matrix for an
example, and sensing units are not shown, but not limited thereto.
In some embodiments, all the sub-pixels 161 having the same color
are turned on repeatedly, and the remaining sub-pixels having
different colors are turned off in one sensing time period, so as
to display one frame in each frame time. For example, all the
second sub-pixels 161b having the second color are driven and
turned on repeatedly to sequentially generate the frames (e.g. a
first frame F1A, a second frame F2A, etc.) while the first
sub-pixels 161a and the third sub-pixels 161c are turned off, so as
to generate light having the same second color in each frame time.
Thus, the sensing units 181 corresponding to the second sub-pixels
161b may detect the light having the second color without being
interfered by other color light, thereby increasing the sensitivity
of the sensing units 181. For example, a circle shown in FIG. 8 may
represent a region of reflected light from each second sub-pixel
161b. In some embodiments, all the sub-pixels 161 turned on in each
frame FA may also be all the first sub-pixels 161a or all the third
sub-pixels 161c. In one embodiment, a region shape of a reflected
light from one sub-pixel 161 may be a circle, a polygen or a
free-shape, but not limited thereto. In some embodiments, an area
of the region is not limited to the drawings in the figures and
also could be adjusted to a suitable size, but not limited
thereto.
[0046] FIG. 9 schematically illustrates sub-pixels turned on in
different frame times according to some embodiments of the present
disclosure. In some embodiments, a first group G1 of the sub-pixels
161 and a second group G2 of the sub-pixels 161 are turned on
sequentially and alternately, and the remaining sub-pixels 161 are
turned off in the sensing time period SP, in which the sub-pixels
161 in first group G1 are different from the sub-pixels 161 in the
second group G2. Specifically, the first group G1 of the sub-pixels
161 is turned on to display one frame F1B in one frame time, and
then the second group G2 of the sub-pixels 161 is turned on to
display another frame F2B in another frame time, in which the first
group G1 of the sub-pixels 161 and the second group G2 of the
sub-pixels 161 may have the same color. As an example, the second
sub-pixels 161b may be the sub-pixels 161 turned on in the sensing
time period. The second sub-pixels 161b in the first group G1 are
not adjacent sub-pixels 161, so the distance between the adjacent
second sub-pixels 161b in the first group G1 can be increased,
thereby reducing the interference of reflected light from different
second sub-pixels 161b, as the circles shown in FIG. 9. Similarly,
the second sub-pixels 161b in the second group G2 may prevent the
interference of different second sub-pixels 161b. For example, one
of the second sub-pixels 161b in the first group G1 may be disposed
between adjacent two of the second sub-pixels 161b in the second
group G2. In other words, the second sub-pixels 161b in the first
group Gland the second sub-pixels 161b in the second group G2 are
respectively arranged in staggered pattern, and in each even row,
each second sub-pixel 161b in the first group G1 and each second
sub-pixel 161b in the second group G2 are alternately arranged.
[0047] FIG. 10 schematically illustrates the sub-pixels turned on
in different frame times according to some embodiments of the
present disclosure. In some embodiments, as compared with FIG. 9,
the first group G1 of the sub-pixels 161 and the second group G2 of
the sub-pixels 161 turned on sequentially may have different
colors. Specifically, the first group G1 of the sub-pixels 161
having one color is turned on to display one frame FIC of one frame
time, and the second group G2 of the sub-pixels 161 having another
color is then turned on to display another frame F2C of another
subsequent frame time while the remaining sub-pixels 161 are turned
off. In some embodiment, after the frame F2C, a third group G3 of
the sub-pixel 161 of the same color as the first group G1 may be
turned on to display another frame F3C of another subsequent frame
time, and then the second group G2 of the sub-pixels 161 is turned
on to display another frame F4C of another subsequent frame time,
so the first group G1 of the sub-pixels 161, the second group G2 of
the sub-pixels 161, the third group G3 of the sub-pixels 161 and
the second group G2 of the sub-pixels 161 are turned on
alternately. As an example, a part of the second sub-pixels 161b
may be the first group G1 of the sub-pixels 161, other part of the
second sub-pixels 161b may be the third group G3 of the sub-pixels
161, and all the first sub-pixels 161a may be the second group G2
of the sub-pixels 161. The second sub-pixels 161b in the first
group G1 may be the same as the first group G1 shown in FIG. 9, and
the second sub-pixels 161b in the third group G3 may be the same as
the second group G2 in FIG. 9, so the patterns of the second
sub-pixels in first group G1 and third group G3 will not be
detailed redundantly. Through alternately turning on the first
group G1, the second group G2, the third group G3 and the second
group G2, the frames F1C, F2C, F3C, F4C can be alternately
generated. It is noted that through alternately turning on the
groups of the sub-pixels with different colors, more sensing units
can be used to detect the biometric feature, and interference of
reflected light from different sub-pixels 161b of different colors
may still be reduced.
[0048] In some embodiments, the first group G1 of the sub-pixels
161 may be all the sub-pixels 161 having the same color (e.g. the
second sub-pixels 161b), the second group G2 of the sub-pixels 161
may be all the sub-pixels 161 having another color (e.g. the first
sub-pixels 161a), and the first group G1 and the second group G2
may be alternately turned on to display the frames F1C, F2C
alternately.
[0049] FIG. 11 schematically illustrates the sub-pixels turned on
in different frame times according to some embodiments of the
present disclosure. In some embodiments, the first group G1 of the
sub-pixels 161 and the second group G2 of the sub-pixels 161 that
have different colors may be turned on at a same time.
Specifically, the first group G1 of the sub-pixels 161 having one
color and the second group G2 of the sub-pixels 161 having another
color are turned on to display one frame F1D of one frame time
while the remaining sub-pixels 161 are turned off. In some
embodiments, after the frame F1D, a third group G3 of the sub-pixel
161 having the same color as the first group G1 and the second
group G2 may be turned on to display another frame F2D of another
subsequent frame time, so the frames F1D, F2D may be displayed
alternately. As an example, apart of the second sub-pixels 161b may
be the first group G1 of the sub-pixels 161, and other part of the
second sub-pixels 161b may be the third group G3 of the sub-pixels
161, and all the first sub-pixels 161a may be the second group G2
of the sub-pixels 161. The second sub-pixels 161b in the first
group G1 may be the same as the first group G1 shown in FIG. 9, and
the second sub-pixels 161b in the third group G3 may be the same as
the second group G2 in FIG. 9, so the patterns of the second
sub-pixels in first group G1 and third group G3 will not be
detailed redundantly. For example, the first sub-pixels 161a have
one of red and green, and the second sub-pixels 161b have the other
one of red and green.
[0050] In some embodiments, after the frame F1D, the first group G1
of the sub-pixels 161 having one color and the second group G2 of
the sub-pixels 161 having another color may be repeatedly turned on
to display another frame F2D in next frame time. In some
embodiments, all the second sub-pixels 161b may be the first group
G1 of the sub-pixels 161.
[0051] As mentioned above, the display device can generate light
pulse 3 to 120 times in the sensing time period, so the sensor
element can receive light 3 to 120 times to accumulate enough
signals and improve the S/N ratio and the sensitivity of the
sensing units. For this reason, the sensor element can be
integrated with the display element into the display region of the
display device without reducing the area of each sub-pixel or
reducing the resolution of the display device, thereby increasing
screen-to-body ratio while providing biometric authentication.
[0052] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the disclosure. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *