U.S. patent application number 14/077346 was filed with the patent office on 2014-05-15 for in-cell multi-touch i display panel system.
This patent application is currently assigned to ORISE TECHNOLOGY CO., LTD.. The applicant listed for this patent is ORISE TECHNOLOGY CO., LTD.. Invention is credited to Chien-Ying HUANG, Yen-Lin HUANG.
Application Number | 20140132560 14/077346 |
Document ID | / |
Family ID | 50681239 |
Filed Date | 2014-05-15 |
United States Patent
Application |
20140132560 |
Kind Code |
A1 |
HUANG; Chien-Ying ; et
al. |
May 15, 2014 |
In-cell multi-touch I display panel system
Abstract
An in-cell multi-touch display panel system includes a
multi-touch LCD display panel and a touch display control
subsystem. The multi-touch LCD display panel has a TFT layer, a
detection electrode layer, and a common-voltage and touch-driving
layer. The detection electrode layer has M first conductor lines
for performing touch detection by sampling touch detection from the
M first conductor lines. The common-voltage and touch-driving layer
has N second conductor lines for receiving common voltage in
display and touch-driving signal in touch detection. In the
detection electrode layer, there are pluralities of detection
electrode areas in the intersections of first conductor lines and
second conductor lines. Each detection electrode area is connected
to a first conductor line by a touch-control transistor. The
M.times.N touch-control transistors are divided in to N sets
corresponding to N second conductor lines respectively.
Inventors: |
HUANG; Chien-Ying; (Hsinchu
City, TW) ; HUANG; Yen-Lin; (Taipei City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ORISE TECHNOLOGY CO., LTD. |
Hsinchu |
|
TW |
|
|
Assignee: |
ORISE TECHNOLOGY CO., LTD.
Hsinchu
TW
|
Family ID: |
50681239 |
Appl. No.: |
14/077346 |
Filed: |
November 12, 2013 |
Current U.S.
Class: |
345/174 |
Current CPC
Class: |
G02F 1/13338 20130101;
G06F 3/041 20130101; G06F 3/0443 20190501; G02F 1/136286 20130101;
G06F 2203/04104 20130101; G02F 1/1368 20130101; G06F 3/0446
20190501; G06F 3/04164 20190501; G06F 3/04166 20190501; G06F 3/0412
20130101; G06F 3/04184 20190501 |
Class at
Publication: |
345/174 |
International
Class: |
G06F 3/044 20060101
G06F003/044 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2012 |
TW |
101142455 |
Claims
1. An in-cell multi-touch display panel system, comprising: a touch
liquid crystal display (LCD) panel including: a thin film
transistor (TFT) layer, having K gate driving lines and L source
driving lines, for driving corresponding display transistors and
capacitors based on a display pixel signal and a display driving
signal so as to perform a display operation, where K and L are
positive integers respectively; a detection electrode layer, having
M first conductor lines, for detecting whether there is an external
object approached based on a touch driving signal, where M is a
positive integer; and a common-voltage and touch-driving layer,
having N second conductor lines, for receiving a common voltage
signal in display and receiving the touch driving signal in touch
detection, where N is a positive integer and K>N, wherein a
plurality of detection electrode areas being respectively
configured at an intersection of the first conductor lines and the
second conductor lines in the detection electrode layer, wherein
each of the first conductor lines is connected to N detection
electrode areas via N touch-control transistor, and the M.times.N
touch-control transistors are divided into N sets corresponding to
the N second conductor lines, respectively; and a touch display
control subsystem, connected to the TFT layer, the detection
electrode layer, and the common-voltage and touch-driving layer, to
provide the display driving signal sequentially to the K gate
driving lines and turn on the corresponding display transistors for
providing the display pixel signal to the L source driving lines
thereby performing a display operation, and provide the touch
driving signal to the N second conductor lines to sample detection
voltages from the M first conductor lines for detecting whether
there is the external object approached; wherein the K gate driving
lines are divided into N sets corresponding to the N second
conductor lines respectively, and when one set of gate driving
lines has the display driving signal, the second conductor line
corresponding to the set of gate driving lines is connected to the
common voltage and, when the touch display control subsystem
provides the touch driving signal to the i-th second conductor
line, the touch display control subsystem determines whether the
display driving signal is provided to the i-th second conductor
lines at the same time, and if not, the touch display control
subsystem provides the touch driving signal to the i-th second
conductor line and M first conductor lines and turns on the i-th
set of touch-control transistors corresponding to the i-th second
conductor line, where i is an index of 2 to N.
2. The in-cell multi-touch display panel system as claimed in claim
1, wherein when the touch display control subsystem provides the
display driving signal to the i-th set of gate driving lines, the
touch display control subsystem provides the touch driving signal
to the (i-1)-th second conductor line and the M first conductor
lines so as to turn on the (i-1)-th set of touch-control
transistors corresponding to the i-th second conductor line.
3. The in-cell multi-touch display panel system as claimed in claim
2, wherein when the touch display control subsystem provides the
display driving signal to the first set of gate driving lines, the
touch display control subsystem provides the common voltage to the
N second conductor lines.
4. The in-cell multi-touch display panel system as claimed in claim
3, wherein after the touch display control subsystem provides the
display driving signal to the N-th set of gate driving lines, the
touch display control subsystem provides the touch driving signal
to the N-th second conductor line and M first conductor lines for
turning on the N-th set of touch-control transistors corresponding
to the N-th second conductor line.
5. The in-cell multi-touch display panel system as claimed in claim
1, wherein the touch display control subsystem concurrently
provides the display driving signal to the N sets of gate driving
lines and provide the touch driving signal to the N second
conductor lines and M first conductor lines according to a
predetermined time.
6. The in-cell multi-touch display panel system as claimed in claim
5, wherein the touch display control subsystem provides the display
driving signal sequentially to the first to N-th sets of gate
driving lines in the predetermined time.
7. The in-cell multi-touch display panel system as claimed in claim
6, wherein the touch display control subsystem provides the touch
driving signal to the M first conductor lines during the
predetermined time, and provides the touch driving sequentially to
the 2-th to N-th second conductor lines and the 1-st second
conductor line in the predetermined time for turning on the set of
touch-control transistors correspondingly.
8. The in-cell multi-touch display panel system as claimed in claim
5, wherein the touch driving signal is non-sequentially provided to
the i-th second conductor line.
9. The in-cell multi-touch display panel system as claimed in claim
1, wherein the M first conductor lines and the L source driving
lines are arranged in a first direction, and the K gate driving
lines and the N second conductor lines are arranged in a second
direction.
10. The in-cell multi-touch display panel system as claimed in
claim 9, wherein the first direction and the second direction are
vertical mutually.
11. The in-cell multi-touch display panel system as claimed in
claim 10, wherein the touch display control subsystem comprises: a
source driver, connected to the touch LCD panel, for driving the
touch LCD panel based on the display pixel signal; a gate driver,
connected to the touch LCD panel, for generating the display
driving signal to drive the touch LCD panel; a detection device,
connected to the touch LCD panel for detecting signals of the touch
LCD panel; a touch driving signal generator, for generating the
touch driving signal; a common voltage generator, for generating
the common voltage; a switch, connected to the touch LCD panel, the
touch driving signal generator, and the common voltage generator; a
touch-control transistor gate driver, connected to the touch LCD
panel, for generating gate driving signals for the N sets of
touch-control transistors so as to drive the N sets of
touch-control transistors to be turned on or off; and a control
device connected to the source driver, the gate driver, the common
voltage generator, the detection device, the touch driving signal
generator, the switch, and the touch-control transistor gate driver
for configuring the switch to provide the touch driving signal or
the common voltage to the N second conductor lines and provide the
touch driving signal to the M first conductor lines, configuring
the gate driver to sequentially output the display driving signal
to the K gate driving lines, configuring the source driver to
output the display pixel signal to the L source driving lines, and
configuring the N sets of touch-control transistors to be turned on
or off.
12. The in-cell multi-touch display panel system as claimed in
claim 11, wherein the control device further comprises: a display
timing controller, connected to the source driver, the gate driver,
and the common voltage generator for providing a timing of the
display pixel signal and the display driving signal by the source
driver and the gate driver, and a timing of the common voltage by
the common voltage generator; and a touch timing controller,
connected to the display timing controller, the detection device,
the touch driving signal generator, the switch, and the
touch-control transistor gate driver, for configuring the switch to
provide the touch driving signal or the common voltage to the N
second conductor lines and provide the touch driving signal to the
M first conductor lines, and configuring the N sets of
touch-control transistors to be turned on or off.
13. The in-cell multi-touch display panel system as claimed in
claim 9, wherein the M first conductor lines and the N second
conductor lines have parasitic capacitance and stray capacitance,
and a mutual capacitance is formed in an overlap between the M
first conductor lines and each of the N second conductor lines.
14. The in-cell multi-touch display panel system as claimed in
claim 13, wherein the detection device comprises M detection
circuits for detecting the mutual capacitance to generate
corresponding M detection signals.
15. The in-cell multi-touch display panel system as claimed in
claim 9, wherein the touch display control subsystem further
comprises: a set of programmable gain amplifiers, connected to the
detection device, for amplifying the M detection signals to
generate M amplified detection signals; a set of analog-to-digital
converters, connected to the set of programmable gain amplifiers,
for converting the M amplified detection signals into M digital
detection signals; and a coordinate determination device, connected
to the set of analog-to-digital converters, for determining a
coordinate of the external object based on the M digital detection
signals.
16. The in-cell multi-touch display panel system as claimed in
claim 15, wherein the M detection circuits consists of an amplifier
and a capacitor respectively, the capacitor has one end connected
to an inverting input end of the amplifier and the other end
connected to an output end of the amplifier, the inverting input
end of the amplifier is connected to one of the M first conductor
lines.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the technical field of
touch panels and, more particularly, to an in-cell multi-touch
display panel system.
[0003] 2. Description of Related Art
[0004] The principle of touch panels is based on different sensing
manners to detect a voltage, current, acoustic wave, or infrared to
thereby detect the coordinate of a touch point on a screen as
touched by a finger or other medium. For example, a resistive touch
panel uses a potential difference between the upper and lower
electrodes to compute the position of a pressed point for detecting
the location of the touch point, and a capacitive touch panel uses
a capacitance change generated in an electrostatic combination of
the arranged transparent electrodes with the touching part of a
human body to generate a current or voltage for detecting the
coordinate of the touching part.
[0005] Upon the principle, the capacitive touch technologies can be
divided into a surface capacitive and a projected capacitive
sensing. The surface capacitive sensing has a simple configuration,
so that the multi-touch implementation is not easy, and the
problems of electromagnetic disturbance (EMI) and noises are
difficult to be overcome. Therefore, the popular trend of
capacitive touch development is toward the projected capacitive
sensing.
[0006] The projected capacitive sensing can be divided into a self
capacitance and a mutual capacitance sensing. The self capacitance
sensing indicates that a capacitance coupling is generated between
a touch object and a conductor line, and a touch occurrence is
decided by measuring a capacitance change of the conductor line.
The mutual capacitance sensing indicates that a capacitance
coupling is generated between two adjacent conductor lines when a
touch occurs.
[0007] A typical self capacitance sensing senses the grounded
capacitance (Cs) on every conductor line. Thus, a change of the
grounded capacitance is used to determine whether an object is
close the capacitive touch panel. The self capacitance or the
grounded capacitance is not a physical capacitor, but parasitic and
stray capacitance on every conductor line. FIG. 1 is a schematic
view of a typical self capacitance sensing. As shown in FIG. 1,
during the first time interval, the driving and sensing devices 110
in a first direction drive the conductor lines in the first
direction in order to further charge the self capacitance (Cs) of
the conductor lines in the first direction. During the second
period, the driving and sensing devices 110 sense the voltages on
the conductor lines in the first direction, thereby obtaining m
data. During the third period, the driving and sensing devices 120
in a second direction drive the conductor lines in the second
direction in order to further charge the self capacitance of the
conductor lines in the second direction. During the fourth period,
the driving and sensing devices 120 sense the voltages on the
conductor lines in the second direction, thereby obtaining n data.
Accordingly, there are m+n data obtained.
[0008] The typical self capacitance sensing of FIG. 1 connects both
a driver circuit and a sensor circuit on the same conductor line in
order to drive the conductor line and sense a signal change on the
same conductor line to thereby decide a magnitude of the self
capacitance. In this case, the advantages include:
[0009] (1) a reduced amount of data since the typical touch panel
has m+n data in a single image only, so as to save the hardware
cost;
[0010] (2) a reduced time required for sensing a touch point since
an image raw data can be quickly fetched due to only two sensing
operations, i.e., concurrently (or one-by-one) sensing all the
conductor lines in the first direction first and then in the second
direction, for completing a frame, as well as a relatively reduced
time required for converting a sensed signal from analog into
digital; and
[0011] (3) a lower power consumption due to the reduced amount of
data to be processed.
[0012] However, such a self capacitance sensing also has the
disadvantages as follows:
[0013] (1) When there is a floating conductor, such as a water
drop, an oil stain, and the like, on the touch panel, it causes an
error decision on a touch point.
[0014] (2) When there are multiple touch points concurrently on the
touch panel, it causes a ghost point effect, so that such a self
capacitance sensing cannot be used in multi-touch applications.
[0015] Another way of driving the typical capacitive touch panel is
to sense a magnitude change of mutual capacitance (Cm) to thereby
determine whether an object is toward the touch panel. Likewise,
the mutual capacitance (Cm) is not a physical capacitor but a
mutual capacitance between the conductor lines 230 in the first
direction and in the second direction. FIG. 2 is a schematic
diagram of a typical mutual capacitance sensing. As shown in FIG.
2, the drivers 210 are located on the first direction (Y), and the
sensors 220 are located on the second direction (X). On the touch
panel, the conductor lines 230 in the first direction, connected to
the drivers 210, are also known as driving lines, and the conductor
lines 230 in the second direction, connected to the sensors 220,
are also known as sensing lines. During the upper half of the first
time interval T1, the drivers 210 drive the conductor lines 230 in
the first direction and use the voltage Vy.sub.--1 to charge the
mutual capacitance (Cm) 250, and at the lower half, all sensors 220
sense voltages (Vo.sub.--1, Vo.sub.--2, . . . , Vo_n) on the
conductor lines 240 in the second direction to thereby obtain n
data. Accordingly, the m*n data can be obtained after m driving
periods.
[0016] Such a mutual capacitance sensing has the advantages as
follows:
[0017] (1) It is easily determined whether a touch is generated
from a human body since a signal generated from a floating
conductor is in a different direction than a grounded conductor;
and
[0018] (2) Every touch point is indicated by a real coordinate, and
the real position of each point can be found when multiple points
are concurrently touched, so that such a mutual capacitance sensing
can easily support the multi-touch applications.
[0019] A typical flat touch display is produced by stacking the
touch panel directly over the flat display. Since the stacked
transparent panel is transparent, the image can be displayed on the
touch panel stacked over the flat display, and the touch panel can
act as an input medium or interface.
[0020] However, such a way requires an increase of the weight of
the touch panel due to the stack resulting in relatively increasing
the weight of the flat display, which cannot meet with the
requirement of compactness in current markets. Furthermore, when
the touch panel and flat display are stacked directly, the
increased thickness reduces the transmittance of rays and increases
the reflectivity and haziness, resulting in greatly reducing the
display quality of the screen.
[0021] To overcome this, the embedded touch control technology is
adapted. The currently developed embedded touch control
technologies are essentially on-cell and in-cell technologies. The
on-cell technology uses a projected capacitive touch technology to
form a sensor on the backside (i.e., a surface for attaching a
polarized plate) of a color filter (CF) for being integrated into a
color filter structure. The in-cell technology embeds sensors in an
LCD cell to thereby integrate a touch element with a display panel
such that the display panel itself is provided with a touch
function without having to be attached or assembled to a touch
panel. Such a technology typically is developed by a TFT LCD panel
factory. The in-cell multi-touch panel technology is getting more
and more mature, and since the touch function is directly
integrated during a panel production process, without adding a
layer of touch glass, the original thickness is maintained and the
cost is reduced.
[0022] FIG. 3(A) is a schematic view of a configuration of a
typical in-cell multi-touch panel 300. In FIG. 3(A), the panel 300
includes a lower polarizer 310, a lower glass substrate 320, a thin
film transistor (TFT) or LTPS layer 330, a liquid crystal (LC)
layer 340, a common voltage and touch driving layer 350, a color
filter layer 360, an upper glass substrate 370, a detection
electrode layer 380, and an upper polarizer 390. As shown in FIG.
3(A), in order to save the cost, a touch sensor is integrated with
an LCD panel, and the common voltage layer of the LCD panel is
located at a layer as same as the drivers of the touch sensor,
thereby forming the common voltage and touch driving layer 350, so
as to achieve the cost saving. The detection electrode layer 380 is
located on the upper glass substrate 370. The TFT or LTPS layer 330
is constructed of thin film transistors (TFTs) or low-temperature
poly-Si film transistors (LTPS) 332 and transparent electrodes
331.
[0023] FIG. 3(B) is a schematic view of another configuration of a
typical in-cell multi-touch panel. As compared with FIG. 3(A), the
difference in FIG. 3(B) is that the detection electrode layer 380
is located beneath the upper glass substrate 370.
[0024] FIG. 3(C) is a schematic view of yet another configuration
of a typical in-cell multi-touch panel. As compared with FIG. 3(A),
the difference in FIG. 3(C) is that the common voltage and touch
driving layer 350 is located beneath the LC layer 340. FIG. 3(D) is
a schematic view of a further configuration of a typical in-cell
multi-touch panel. As compared with FIG. 3(C), the difference in
FIG. 3(D) is that the detection electrode layer 380 is located
beneath the upper glass substrate 370.
[0025] The configuration of the in-cell multi-touch panel in any
one of FIGS. 3(A), 3(B), 3(C) and 3(D) uses a time sharing to
divide the time for one display frame into a display cycle and a
touch cycle to thereby commonly use the common voltage layer of the
display panel and the driving layer of the touch sensor. The
timings for FIGS. 3(A), 3(B), 3(C) and 3(D) are shown in FIGS.
4(A), 4(B), 4(C) and 4(D), respectively.
[0026] As shown in FIG. 4(A), the time for one display frame is
divided into one display cycle and one touch cycle, and the frame
of the display panel is displayed in the display cycle before the
touch sensing is performed in the touch cycle. As shown in FIG.
4(B), the touch sensing is performed before the frame of the
display panel is displayed. As shown in FIG. 4(C), partial lines of
one frame are displayed in a section A, and then the touch sensing
is performed. Finally, the remaining lines of the frame are
displayed in a section B. As shown in FIG. 4(D), a display of the
vertical synchronous signal (Vsync) is changed such that the frame
of the display panel is displayed when the vertical synchronous
signal (Vsync) is at a high level. Conversely, when the vertical
synchronous signal (Vsync) is at a low level, the touch sensing is
performed.
[0027] In US Patent Publication 2012/0050217 entitled "Display
device with touch detection function, control circuit, driving
method of display device with touch detection function, and
electronic unit", the timing of the first embodiment (shown in FIG.
8 of the patent publication) is as same as that in FIG. 4(A), in
which the frame is displayed before the touch sensing is performed.
The timing of the second embodiment (shown in FIG. 17 of the patent
publication) is as same as that in FIG. 4(C), in which the partial
lines of the frame is displayed in the section A, and then the
touch sensing is performed; finally the remaining lines of the
frame is displayed in the section B.
[0028] For such a time sharing, as the resolution of the display
panel is getting higher, the number of pixels to be driven by the
display driver IC is getting more, and thus the time required
becomes longer. In this case, the display frame rate has to be
maintained at 60 Hz or above, i.e., each frame only contains 16.6
ms. However, it is increasingly difficult to perform the image
displaying and touch sensing in 16.6 ms due to the higher and
higher resolution of the display panel. Therefore, the increasing
image resolution is limited.
[0029] Accordingly, it is desirable to provide an improved in-cell
multi-touch display panel system to mitigate and/or obviate the
aforementioned problems.
SUMMARY OF THE INVENTION
[0030] The object of the present invention is to provide an in-cell
multi-touch display panel system, which can overcome the prior
problem of limiting the increased resolution of a display panel and
share the same transparent conductive layer in driving of the
common voltage layer (Vcom) and touch detection devices of an LCD
panel, thereby saving the cost.
[0031] To achieve the object, there is provided an in-cell
multi-touch display panel system, which comprises: a touch liquid
crystal display (LCD) panel including: a thin film transistor (TFT)
layer having K gate driving lines and L source driving lines for
driving corresponding display transistors and capacitors based on a
display pixel signal and a display driving signal so as to perform
a display operation, where K and L are each a positive integer; a
detection electrode layer having M first conductor lines for
detecting whether there is an external object approached based on a
touch driving signal, where M is a positive integer; and a
common-voltage and touch-driving layer having N second conductor
lines for receiving a common voltage signal in display and
receiving a touch driving signal in touch detection, where N is a
positive integer and K>N, wherein, in the detection electrode
layer, there are a plurality of detection electrode areas, each
being configured at an intersection of each first conductor line
and each second conductor line, and connected to a corresponding
first conductor line via a touch-control transistor, in which each
first conductor line is connected to N detection electrode areas
via N touch-control transistor, and the M.times.N touch-control
transistors are divided into N sets corresponding to the N second
conductor lines, respectively; and a touch display control
subsystem connected to the TFT layer, the detection electrode
layer, and the common-voltage and touch-driving layer to provide
the display driving signal sequentially to the K gate driving lines
and turn on the corresponding display transistors for providing the
display pixel signal to the L source driving lines thereby
performing a display operation, and provide the touch driving
signal to the N second conductor lines and sample detection
voltages from the M first conductor lines for detecting whether
there is the external object approached; wherein the K gate driving
lines are divided into N sets each corresponding to one of the N
second conductor lines, such that, when one set of gate driving
lines has the display driving signal, the second conductor line
corresponding to the set of gate driving lines is connected to the
common voltage and, when the touch display control subsystem
provides the touch driving signal to the i-th second conductor
line, the touch display control subsystem determines whether the
display driving signal is provided to the i-th second conductor
lines at the same time and, if not, provides the touch driving
signal to the i-th second conductor line and M first conductor
lines and turns on the i-th set of touch-control transistors
corresponding to the i-th second conductor line, where i is an
index of 2 to N.
[0032] Other objects, advantages, and novel features of the
invention will become more apparent from the following detailed
description when taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a schematic diagram of a typical self capacitance
sensing;
[0034] FIG. 2 is a schematic diagram of a typical mutual
capacitance sensing;
[0035] FIGS. 3(A)-3(D) show the configuration of a typical in-cell
multi-touch panel;
[0036] FIGS. 4(A)-4(D) show the timing of a typical in-cell
multi-touch panel;
[0037] FIG. 5 is a block diagram of an in-cell multi-touch display
panel system according to the invention;
[0038] FIG. 6 schematically illustrates the detection electrode
layer and the common-voltage and touch-driving layer in accordance
with the present invention;
[0039] FIG. 7 is a circuit diagram of the in-cell multi-touch
display panel of FIG. 5 in accordance with an embodiment of the
present invention;
[0040] FIG. 8 shows a timing of an embodiment of the touch display
control subsystem in display and touch detection according to the
invention;
[0041] FIG. 9 is a timing of another embodiment of the touch
display control subsystem in display and touch detection according
to the invention;
[0042] FIG. 10 is a timing of still another embodiment of the touch
display control subsystem in display and touch detection according
to the invention;
[0043] FIG. 11 is a timing of yet another embodiment of the touch
display control subsystem in display and touch detection according
to the invention;
[0044] FIG. 12 is a circuit schematic of the in-cell multi-touch
display panel system according to another embodiment of the
invention; and
[0045] FIG. 13 is a timing of further another embodiment of the
touch display control subsystem in display and touch detection
according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0046] FIG. 5 is a block diagram of an in-cell multi-touch display
panel system 500 according to the invention. The in-cell
multi-touch display panel 500 includes a touch LCD panel 510 and a
touch display control subsystem 520.
[0047] The touch LCD panel 510 has a thin film transistor (TFT)
layer 330, a detection electrode layer 515, and a common-voltage
and touch-driving layer 350, wherein the three layers 330, 350 and
515 can be combined and stacked into one of the configurations
shown in FIGS. 3(A)-3(D).
[0048] The TFT layer 330 has K gate driving lines (G1, G2, . . . ,
GK) and L source driving lines (SOURCE1, SOURCE2, . . . , SOURCEL)
in order to drive display transistors DTr and capacitors C.sub.LC
corresponding to pixels of the LCD panel 510 based on a display
pixel signal and a display driving signal in display, where K, L
are each a positive integer. For convenience of description, in
this embodiment, we have K=800 and L=600.
[0049] The active element of the TFT transistor layer 330 is the
TFT in this embodiment. In other embodiments, the active element
can be a low temperature polysilicon (LTPS) TFT, indium gallium
zinc oxide (IGZO) TFT, or continuous grain silicon (CGS).
[0050] Specifically, the detection electrode layer 515 of the
present invention is different from the detection electrode layer
380 in prior art. The detection electrode layer 515 has M first
conductor lines (RX1, RX2, . . . , RX12) for detecting whether
there is an external object approached based on a touch driving
signal, where M is a positive integer. In this embodiment, we have
M=12.
[0051] The common-voltage and touch-driving layer 350 has N second
conduct lines (Vcom1, Vcom2, . . . , Vcom20) in order to receive a
common voltage signal in display and receive the touch driving
signal in touch detection, where N is a positive integer, and
K>N. In this embodiment, we have N=20.
[0052] FIG. 6 schematically illustrates the detection electrode
layer 515 and the common-voltage and touch-driving layer 350 in
accordance with the present invention. In the detection electrode
layer 515, there are a plurality of detection electrode areas 601,
each being configured at an intersection of each first conductor
line (RX1, RX2, . . . , RX12) and each second conductor line
(Vcom1, Vcom2, . . . , Vcom20). Each detection electrode area 601
is connected to the corresponding first conductor line (RX1, RX2, .
. . , RX12) via a touch-control transistor 603. Each first
conductor line (RX1, RX2, . . . , RX12) is connected to N detection
electrode areas 601 via N touch-control transistor 603, where N is
20 in this embodiment. The M.times.N (12.times.2) touch-control
transistors 603 and detection electrode areas 601 are divided into
N (=20) sets, each set of touch-control transistors 603 and
detection electrode areas 601 corresponding to a second conductor
line. The gates of the touch-control transistor 603 in each set are
connected to a corresponding touch gate driving line (TG1, TG1, . .
. , TG20), so as to turn on or turn off the set of touch-control
transistors by using the touch gate driving line (TG1, TG1, . . . ,
TG20).
[0053] In order to save cost, the first conductor lines (RX1, RX2,
. . . , RX12), detection electrode areas 601 and touch-control
transistors 603 in the detection electrode layer 515 can be
designed to be disposed in the thin film transistor layer (TFT or
LTPS) 330.
[0054] When the touch display control subsystem 520 provides the
touch driving signals to the i-th second conductor line and M first
conductor lines (RX1, RX2, . . . , RX12), the touch display control
subsystem 520 turns on the i-th set of touch-control transistors
603 corresponding to the i-th second conductor line. As shown in
FIG. 6, when the touch display control subsystem 520 provides the
touch driving signal to the 2-nd second conductor line Vcom2, the
touch display control subsystem 520 turns on the second set of
touch-control transistors 603 corresponding to the 2-nd second
conductor line Vcom2. Therefore, the voltages detected by the
second set of detection electrode areas 601 can be reflected to the
M first conductor lines (RX1, RX2, . . . , RX12), respectively. At
this moment, the other sets of touch-control transistors 603 are
not turned on and thus the touch driving signals on the 2-nd second
conductor line Vcom2 detected by the other sets of detection
electrode areas 601 are not reflected to the M first conductor
lines (RX1, RX2, . . . , RX12).
[0055] When the touch display control subsystem 520 provides the
touch driving signal to the 2-nd second conductor line Vcom2, it
indicates that the touch display control subsystem 520 wants to
detect whether there is a touch around the 2-nd second conductor
line Vcom2. In the present invention, only the second set of
touch-control transistors 603 corresponding to the 2-nd second
conductor line Vcom2 is turned on, while the other sets of
touch-control transistors 603 are not turned on. Thus, the touch
driving signals on the 2-nd second conductor line Vcom2 detected by
the other sets of detection electrode areas 601 are not reflected
to the M first conductor lines (RX1, RX2, . . . , RX12), thereby
enabling the touch detection to be more accurate.
[0056] In this embodiment, the detection electrode area 601 is a
diamond shape. Alternatively, the detection electrode area 601 can
be a square, rectangle or round shape.
[0057] The M first conductor lines (RX1, RX2, . . . , RX12) and L
source driving lines (SOURCE 1, SOURCE 2, . . . , SOURCE L) are
disposed along a first direction (Y direction), and the K gate
driving lines (G1, G2, . . . , G800) and N second conductor lines
(Vcom1, Vcom2, . . . , Vcom20) are disposed along a second
direction (X direction), where the first direction is substantially
vertical with the second direction.
[0058] In this embodiment, the K gate driving lines (G1, G2, . . .
, G800) correspond to the N second conductor lines (Vcom1, Vcom2, .
. . , Vcom20). That is, the gate driving lines G1 to G40 correspond
to the second conductor line Vcom1, the gate driving lines G41 to
G80 correspond to the second conductor line Vcom2, and so on. In
other words, the gate driving lines G1 to G40 are the first group,
the gate driving lines G41 to G80 are the second group, . . . , and
the gate driving lines G761 to G800 are twentieth group. More
specifically, the first group of gate driving lines G1 to G40 is
disposed at the thin film transistor layer 30 and the corresponding
second conductor line Vcom1 is disposed at the same position of the
common-voltage and touch-driving layer 350, while the same
configuration applies to other groups.
[0059] When K is not an integral multiple of N, for example K=802
and N=20, the gate driving lines G1 to G41 correspond to the second
conductor line Vcom1, the gate driving lines G42 to G82 correspond
to the second conductor line Vcom2, the gate driving lines G83 to
G122 correspond to the second conductor line Vcom3, and so on.
[0060] The touch display control subsystem 520 is connected to the
thin film transistor layer 330, the detection electrode layer 515,
and the common-voltage and touch-driving layer 350. The touch
display control subsystem 520 sequentially provides the display
driving signal to the K (=800) gate driving lines for turning on
the corresponding display transistors DTr and providing the display
pixel signals to the L (=600) source driving lines, so as to
execute display operation.
[0061] The touch display control subsystem 520 sequentially
provides the touch driving signal to the N second conductor lines
(Vcom1, Vcom2, . . . , Vcom20) and M first conductor lines (RX1,
RX2, . . . , RX12), and turns on the i-th set of touch-control
transistors corresponding to the i-th second conductor line, so as
to allow the M first conductor lines (RX1, RX2, . . . , RX12) to
sample detection voltages thereby detecting whether there is an
external object approached.
[0062] The K (=800) gate driving lines are divided into N (=20)
sets, each set of gate driving lines corresponding to a second
conductor line. When one set of the gate driving lines has the
display driving signal, the corresponding second conductor line is
connected to the common voltage (Vcom) for use as grounding in
display operation.
[0063] FIG. 7 is a circuit diagram of the in-cell multi-touch
display panel 500 of FIG. 5 in accordance with an embodiment of the
present invention. As shown, the touch display control subsystem
520 includes a source driver 705, a gate driver 710, a detection
device 715, a touch driving signal generator 720, a common voltage
generator 725, a switch 730, a control device 735, a set of
programmable gain amplifiers 740, a set of analog to digital
converters 745, a coordinate determination device 750, and a
touch-control transistor gate driver 755.
[0064] The source driver 705 is connected to the touch LCD panel
510 for driving the touch LCD panel 510 based on the display pixel
signal.
[0065] The gate driver 710 is connected to the touch LCD panel 510
for generating the display driving signal, so as to drive the touch
LCD panel 510.
[0066] The detection device 715 is connected to the touch LCD panel
510 for detecting signals of the touch LCD panel 510.
[0067] The touch driving signal generator 720 is provided to
generate touch driving signal VIN. Specifically, the touch driving
signal generator 720 is able to generate touch driving signal VIN
required by the self capacitance technology.
[0068] The common voltage generator 725 is provided to generate a
common voltage (Vcom). Specifically, the common voltage generator
725 is able to generate DC common voltage (DC-Vcom) or AC common
voltage (DC-Vcom).
[0069] The switch 730 is connected to the touch LCD panel 510, the
touch driving signal generator 720, and the common voltage
generator 725.
[0070] The control device 735 includes a display timing controller
7351 and a touch timing controller 7353. The control device 735 is
connected to the source driver 705, the gate driver 710, the common
voltage generator 725, the detection device 715, the touch driving
signal generator 720, the switch 730, the set of programmable gain
amplifiers 740, the set of analog to digital converters 745, the
coordinate determination device 750, and the touch-control
transistor gate driver 755, thereby configuring the switch 730 to
provide the touch driving signal or the common voltage (Vcom) to
the N second conductor lines and provide the touch driving signal
to the M first conductor lines, configuring the gate driver 710 to
sequentially output the display driving signal to the K gate
driving lines, configuring the source driver 705 to output the
display pixel signal to the L source driving lines, and configuring
the N sets of touch-control transistors to be turned on and
off.
[0071] The display timing controller 7351 is connected to the
source driver 705, the gate driver 710, and the common voltage
generator 725 for providing the timing of outputting the display
pixel signal and the display driving signal to the source driver
705 and the gate driver 710, and the timing of generating the
common voltage (Vcom) to the common voltage generator 725.
[0072] The touch timing controller 7353 is connected to the display
timing controller 7351, the detection device 715, the touch driving
signal generator 720, the switch 730, and the touch-control
transistor gate driver 755, thereby configuring the switch to
provide the touch driving signal VIN or the common voltage (Vcom)
to the N second conductor lines and provide the touch driving
signal to the M first conductor lines, and configuring the N sets
of touch-control transistors to be turned on or off.
[0073] The set of programmable gain amplifiers 740 is connected to
the detection device 715 for amplifying the M detection signals
thereby generating M amplified detection signals.
[0074] The set of analog to digital converters 745 is connected to
the set of programmable gain amplifiers 740 for converting the M
amplified detection signals into M digital detection signals.
[0075] The coordinate determination device 750 is connected to the
set of analog to digital converters 745 for determining the
coordinate position of the external object based on the M digital
detection signals. Each of the M first conductor lines and the N
second conductor lines has parasitic capacitance and stray
capacitance. There is mutual capacitance (Cm) formed at an overlap
of each of the M first conductor lines and each of the N second
conductor lines. Each of the first conductor lines (RX1, RX2, . . .
, RX12) and the second conductor lines (Vcom1, Vcom2, . . . ,
Vcom20) has a capacitance with respect to ground, defined as self
capacitance (Cs).
[0076] The detection device 715 has M detection circuits for
detecting the self capacitance, so as to generate the corresponding
M detection signals.
[0077] Each detection circuit of the detection device 715 is
composed of an amplifier 7151 and a resistor 7153. The resistor
7153 has one end connected to the output end of the amplifier 7151
and the other end connected to the negative output end of the
amplifier 7151 and one of the M first conductor lines (RX1, RX2, .
. . , RX12). The positive input end of the amplifier 7151 is
connected to receive the touch driving signal VIN.
[0078] As shown in FIG. 7, in performing touch detection, the touch
driving signal generator 720 is provided to generate the touch
driving signal VIN, wherein the touch driving signal VIN is
provided to the 1-st second conductor line Vcom1 and also provided
to the M first conductor lines (RX1, RX2, . . . , RX12), and the
touch timing controller 7353 also drives the touch-control
transistor gate driver 755, so as to turn on the first set of
touch-control transistors through the touch gate driving line TG1.
Because the resistance of the resistor 7153 is relatively small,
the end A can be deemed as the touch driving signal VIN and. At the
same time, the end B is the touch driving signal VIN, indicating
that the mutual capacitance Cm between the end A and the end B is
deemed to be not existed due to short circuit. That is, in
performing self capacitance touch detection, the present invention
is not influenced by mutual capacitance Cm, so as to increase the
accuracy in touch detection.
[0079] That is, at first, the first second conductor line Vcom1 is
at voltage level of DC-Vcom, and then the gate driving lines (G1,
G2, . . . , G800) sequentially provide the display driving signal
and the source driving lines (SOURCE 1, SOURCE 2, . . . , SOURCE L)
sequentially provide the display pixel signal for refreshing
display, wherein the gate driving line turns on the display
transistor DTr for a pixel so as to allow the display pixel signal
to charge the capacitor C.sub.LC. When completing the gate driving
lines (G1 to G40) corresponding the 1-st second conductor line
Vcom1, the touch driving signal VIN is then provided to the 1-st
second conductor line Vcom1 and the M first conductor lines (RX1,
RX2, . . . , RX12) for detecting the self capacitance (Cs) of each
conductor line on the panel, thereby determining whether there is a
touch.
[0080] At the same time, the touch driving signal VIN is also
provided to the M first conductor lines (RX1, RX2, . . . , RX12) to
drive the mutual capacitance Cm, and the voltages at two ends of
the mutual capacitance are equal at this moment so that there is no
charge/discharge in the mutual capacitance Cm. That is, the current
on the M first conductor lines (RX1, RX2, . . . , RX12) is caused
from charging/discharging the self capacitance (Cs) with respect to
the ground. As a result, it is able to easily exclude the influence
from mutual capacitance Cm so as to determine whether there is a
touch, wherein only the self capacitance Cs with respect to ground
is determined when there is a touch.
[0081] The operation principle of the touch display control
subsystem 520 is described hereinafter. When the touch display
control subsystem 520 provides the touch driving signal to the i-th
second conductor line, it first determines whether the display
driving signal is concurrently provided and, if not, it provides
the touch driving signal to the i-th second conductor line. Thus,
both display and touch detection can be made concurrently.
[0082] FIG. 8 shows a timing of an embodiment of the touch display
control subsystem 520 in display and touch detection according to
the invention. First, when the touch display control subsystem 520
provides the display driving signal to the first set of gate
driving lines, it provides the common voltage (Vcom) to the N
second conductor lines in order to connect the N second conductor
lines to the common voltage (Vcom).
[0083] When the touch display control subsystem 520 provides the
display driving signal to the i-th set of gate driving lines, it
provides the touch driving signal to the (i-1)-th second conductor
line and the M first conductor lines, and turns on the (i-1)-th set
of touch-control transistors corresponding to the (i-1)-th second
conductor line, where i=2 to N. When the touch display control
subsystem 520 provides the display driving signal to the N-th set
of gate driving lines, it provides the touch driving signal to the
N-th second conductor line and the M first conductor lines, and
turns on the N-th set of touch-control transistors corresponding to
the N-th second conductor line.
[0084] The timing of FIG. 8 shows that a change in partial timing
is not necessary completely. Namely, the timing of using the touch
display control subsystem 520 to provide the display driving signal
to the K gate driving lines (G1, G2, . . . , G800) is as same as
that of the original LCD panel. As shown in FIG. 8, when a vertical
synchronous signal (Vsync) is inputted, the first group of gate
driving lines G1-G40 corresponding to the second conduct line Vcom1
at the same location is sequentially driven and, at this moment,
the second conductor line Vcom1 has no change. The touch display
control subsystem 520 provides the common voltage (Vcom) to the
second conductor line Vcom1 and other N-1 second conductor lines to
thereby connect the N second conductor lines to the common voltage
(Vcom).
[0085] When the gate driving line G41 is driven, the touch display
control subsystem 520 starts to provide the touch driving signal to
the second conductor line Vcom1 and all of the M first conductor
lines and turn on the first set of touch-control transistors
corresponding to the second conductor line Vcom1, and samples touch
voltages from the M first conductor lines (RX1, RX2, . . . , RX12)
for detecting whether an external object approaches to the second
conductor line Vcom1.
[0086] When the gate driving line G81 is driven, the touch display
control subsystem 520 starts to provide the touch driving signal to
the second conductor line Vcom2 and all of the M first conductor
lines and turn on the second set of touch-control transistors
corresponding to the second conductor line Vcom2, and samples touch
voltages from the M first conductor lines (RX1, RX2, . . . , RX12)
for detecting whether an external object approaches to the second
conduct line Vcom2.
[0087] As shown in FIG. 8, the display and touch data associated
with the second conductor lines Vcom1 to Vcom20 is sequentially
completed, and there is no need of performing the time sharing or
reducing the driving time in display timing due to a touch
detection to be performed.
[0088] FIG. 9 is a timing of another embodiment of the touch
display control subsystem 520 in display and touch detection
according to the invention. As shown in FIG. 9, the touch display
control subsystem 520 concurrently provides the display driving
signal to the N sets of gate driving lines (G1, G2, . . . , G800)
and the touch driving signal to the N second conductor lines
(Vcom1, Vcom2, . . . , Vcom20) and M first conductor lines in a
predetermined time. As shown in FIG. 9, the touch display control
subsystem 520 provides the display driving signal to the first to
N-th groups of gate driving lines sequentially in a predetermined
time when a VBP time passes after the vertical synchronous signal
(Vsync). At the same time, the touch display control subsystem 520
provides the touch driving signal to the M first conductor lines
sequentially in the predetermined time (after the VBP time), and
also provides the touch driving signal to the 2-nd to N-th second
conductor lines and the 1-st second conductor line sequentially in
the predetermined time.
[0089] FIG. 9 shows another similar concept of control timing,
which is assumed that the time required for driving one second
conduct line Vcom1 is smaller than that for driving one group of
gate driving lines G1 to G40. Thus, after the vertical synchronous
signal Vsync, the subsystem 520 first drives the first group of
gate driving lines G1 to G40 sequentially, where the first group of
gate driving lines G1 to G40 are located in a position as same as
the second conductor line Vcom1 in the common-voltage and
touch-driving layer 350. When the touch display control subsystem
520 sequentially drives the first group of gate driving lines G1 to
G40, it provides the touch driving signal to the M first conductor
lines and the second conduct line Vcom2 and, at this moment, turns
on the second set of touch-control transistors corresponding to the
second conductor line Vcom2, provides the touch driving signal to
the second conductor lines Vcom3, Vcom4, . . . , Vcom20
sequentially, and finally provides the touch driving signal to the
second conductor line Vcom1 thereby completing the touch scanning
procedure for one full frame. When the touch display control
subsystem 520 provides the touch driving signal to the second
conductor lines Vcom3, Vcom4, . . . , Vcom20 sequentially, it
sequentially turns on the set of touch-control transistors
corresponding to the aforementioned second conductor lines.
[0090] Such a driving scheme as shown in FIG. 9 can be used without
any problem if it is ensured that the touch driving signal is
provided to the second conductor line Vcom1 after the display
driving signal G41 and above are provided by the touch display
control subsystem 520.
[0091] Furthermore, it is noted that the scanning frequency of the
touch lines is not necessary to be consistent with that of the
display lines, and the scanning frequency of the touch screen is
not necessary to be consistent with that of the display screen. In
addition, the scan time of the touch screen at start is not
necessary to be synchronous with the display time of the display
screen at start, and the driving frequency of the touch driving
signal on the second conductor lines is not necessary to be
consistent with the scanning frequency of the display lines. That
is, when the display screen has an updated frequency of 60 Hz, the
scanning frequency of the touch screen is not limited to 60 Hz.
[0092] FIG. 10 is a timing of still another embodiment of the touch
display control subsystem 520 in display and touch detection
according to the invention. When the touch display control
subsystem 520 non-sequentially provides the touch driving signal to
the i-th second conductor line, it first determines whether the
display driving signal is also provided to the i-th set of gate
driving lines. If yes, the touch display control subsystem 520
provides the touch driving signal to the other second conductor
line except the i-th second conductor line, and otherwise the touch
display control subsystem 520 provides the touch driving signal to
the i-th second conductor line. As shown in FIG. 10, the touch
display control subsystem 520 non-sequentially provides the touch
driving signal to the i-th second conductor line.
[0093] FIG. 11 is a timing of yet another embodiment of the touch
display control subsystem 520 in display and touch detection
according to the invention, which is similar to that of FIG. 9
except that the common voltage generator 725 generates AC common
voltage (AC-Vcom). That is, when the touch display control
subsystem 520 sequentially provides the display driving signal to
the first set of gate driving lines G1 to G40, the common voltage
generator 725 generates and provides AC common voltage (AC-Vcom) to
the corresponding second conductor line Vcom1 at the same time.
Thus, on the second conductor line Vcom1, there is AC common
voltage (AC-Vcom) but not the touch driving signal. At this moment,
the touch display control subsystem 520 provides the touch driving
signal to the second conductor line Vcom2.
[0094] FIG. 12 is a circuit schematic of the in-cell multi-touch
display panel system 500 according to another embodiment of the
invention, which is similar to that of FIG. 7 except for the
detection device. The detection device 1215 in FIG. 12 has M
detection circuits, including an operational amplifier 1201 and a
feedback capacitor 1203 respectively. The feedback capacitor 1203
has one end connected to the inverting input end of the operational
amplifier 1201 and the other end connected to the output end of the
operational amplifier 1201. The inverting input end of the
operational amplifier 1201 is connected to one of the M first
conductor lines. The non-inverting input end of the operational
amplifier 1201 is connected to the common voltage (Vcom).
[0095] The circuit of FIG. 12 is provided to detect the mutual
capacitance Cm between the M first conductor lines (RX1, RX2, . . .
, RX12) and the N second conductor lines (Vcom1, Vcom2, . . . ,
Vcom20) for use as a standard to determine a touch, wherein the
circuit of FIG. 12 is different from the circuit of FIG. 7 for
detecting self capacitance (Cs) with respect to ground. The circuit
for detecting the mutual capacitance Cm makes use of charge
integrators and thus does not provide the touch driving signal VIN
to the M first conductor lines (RX1, RX2, . . . , RX12), while the
voltages of the M first conductor lines (RX1, RX2, . . . , RX12)
are kept to be constant.
[0096] FIG. 13 is a timing of further another embodiment of the
touch display control subsystem 520 in display and touch detection
according to the invention, which is provided to proceed with a
mutual capacitance detection, wherein the voltages of the M first
conductor lines are kept to be constant.
[0097] In view of the foregoing, it is known that, in addition to
integrating the touch sensing circuits into a typical LCD panel,
the invention can share the common voltage signal and touch driving
layer by the common voltage layer of the LCD panel and the drivers
of the touch sensor thereby saving the cost. The prior art uses a
time sharing for display and touch detection, rather than sharing
the same layer of transparent conductors by the common voltage
layer of the LCD panel and the drivers of the touch sensor.
Further, the invention uses different timing to drive a display on
the LCD panel and perform a touch detection at the same time, which
can overcome the problem of insufficient time for driving the
display and the touch detection in time sharing.
[0098] Furthermore, when the touch display control subsystem 520
provides the touch driving signal to the i-th second conductor line
and the M first conductor lines (RX1, RX2, . . . , RX12), it only
turns on the i-th set of touch-control transistors corresponding to
the i-th second conductor line. Thus, the touch driving signal on
the 2-nd second conductor line Vcom2 detected by the other sets of
detection electrode areas 601 will not be reflected to M first
conductor lines (RX1, RX2, . . . , RX12), thereby increasing the
accuracy in touch detection.
[0099] Accordingly, it is clear from the above description that the
invention has the advantages as follows:
[0100] 1. The same layer of transparent conductors can be shared by
the common voltage layer of the LCD panel and the drivers of the
touch detection, thereby the cost will be saved. In addition,
active devices are used for control so as to turn on the capacitors
only in the range of detection thereby reducing the parasitic
capacitance on the first conductor line and increasing the
sensitivity of detection.
[0101] 2. When the LCD panel is driven, in addition to the second
conductor lines corresponding to the gate driving lines (G1, G2, .
. . , GK) in display, at least one of the other second conductor
lines can be driven in touch detection at the same time. Namely,
the display on the LCD panel and the touch detection in the
invention can be performed concurrently with the respective signals
(DC-Vcom, AC-Vcom, VIN) outputted to the different second conductor
lines (Vcom1, Vcom2, . . . , VcomN), so that there is no need to
wait between the panel display and the touch detection.
[0102] 3. The timing of the gate driving lines (G1, G2, . . . , GK)
and source driving lines (SOURCE1, SOURCE2, . . . , SOURCEL) on the
LCD panel can maintain in touch detection without a change, and the
second conductor lines (Vcom1, Vcom2, . . . , VcomN) on the
updating area or areas of the LCD panel can be avoided by using the
touch clock controller to read the signals (such as Vsync/Hsync)
associated with the LCD panel in operation.
[0103] 4. It allows the touch signal to automatically avoid the
second conductor lines (Vcom1, Vcom2, . . . , VcomN) corresponding
to the gate driving lines (G1, G2, . . . , GK) in display, thereby
preventing the common voltage signal (Vcom) and the touch driving
signal from being concurrently provided to the same second
conductor line (Vcom1, Vcom2, . . . , VcomN). Therefore, the
display timing of the LCD panel is not required to be changed.
Namely, the touch detection is not necessary to be synchronous with
the display on the LCD panel. To implement an asynchronous
configuration with a frequency of 60 Hz for the display on the LCD
panel and a frequency of 100 Hz for the touch detection can be
easily.
[0104] Although the present invention has been explained in
relation to its preferred embodiment, it is to be understood that
many other possible modifications and variations can be made
without departing from the spirit and scope of the invention as
hereinafter claimed.
* * * * *