U.S. patent application number 12/608372 was filed with the patent office on 2010-05-06 for touch controller having increased sensing sensitivity, and display driving circuit and display device and system having the touch controller.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Hae-yong AHN, San-ho BYUN, Hwa-hyun CHO, Yoon-kyung CHOI, Hyoung-rae KIM, Sang-woo KIM, Hyung-dal KWON, Jong-kang PARK, Jae-suk YU.
Application Number | 20100110040 12/608372 |
Document ID | / |
Family ID | 42130790 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100110040 |
Kind Code |
A1 |
KIM; Hyoung-rae ; et
al. |
May 6, 2010 |
TOUCH CONTROLLER HAVING INCREASED SENSING SENSITIVITY, AND DISPLAY
DRIVING CIRCUIT AND DISPLAY DEVICE AND SYSTEM HAVING THE TOUCH
CONTROLLER
Abstract
A touch controller includes a touch data generator that is
connected to a plurality of sensing lines, the touch data generator
sensing a change in capacitance of a sensing unit connected to each
of the sensing lines and generating touch data by processing the
sensing signal corresponding to the result of sensing; and a signal
processor that controls a timing of generating the touch data by
receiving at least one piece of timing information for driving a
display panel from a timing controller, and then providing either
the timing information or a signal generated from the timing
information as a control signal to the touch data generator.
Inventors: |
KIM; Hyoung-rae;
(Hwaseong-si, KR) ; CHOI; Yoon-kyung; (Yongin-si,
KR) ; CHO; Hwa-hyun; (Seoul, KR) ; KIM;
Sang-woo; (Suwon-si, KR) ; AHN; Hae-yong;
(Seoul, KR) ; KWON; Hyung-dal; (Suwon-si, KR)
; PARK; Jong-kang; (Suwon-si, KR) ; BYUN;
San-ho; (Bucheon-si, KR) ; YU; Jae-suk;
(Seoul, KR) |
Correspondence
Address: |
VOLENTINE & WHITT PLLC
ONE FREEDOM SQUARE, 11951 FREEDOM DRIVE SUITE 1260
RESTON
VA
20190
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
42130790 |
Appl. No.: |
12/608372 |
Filed: |
October 29, 2009 |
Current U.S.
Class: |
345/174 |
Current CPC
Class: |
G06F 3/0446 20190501;
G06F 3/04184 20190501; G02F 1/13338 20130101; G09G 2310/08
20130101; G06F 1/3215 20130101; G09G 3/2092 20130101; G09G 3/2007
20130101; H01L 27/323 20130101; G06F 1/3237 20130101; G06F 3/0412
20130101; G06F 1/3265 20130101; G09G 2354/00 20130101 |
Class at
Publication: |
345/174 |
International
Class: |
G06F 3/044 20060101
G06F003/044 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 30, 2008 |
KR |
10-2008-0107294 |
Mar 18, 2009 |
KR |
10-2009-0023042 |
Oct 19, 2009 |
KR |
10-2009-0099318 |
Claims
1. A touch data generator configured for use within a touch screen
controller (TSC) in a touch display device comprising a touch
screen panel, and a display driving circuit (DDI), wherein the
touch data generator comprises: an amplifier comprising a positive
input terminal receiving an alternating reference voltage, a
negative input terminal receiving a sensor input, an output
terminal providing an output voltage, and a resistance-capacitance
(RC) feedback circuit biasing the amplifier, wherein the sensor
input comprises a sensor capacitance including a touch capacitance
and a capacitive background noise component, and the amplifier is
configured to remove the capacitive background noise component from
the sensor input while amplifying the reference voltage in response
to the touch capacitance.
2. The touch data generator of claim 1, wherein the DDI comprises a
timing controller configured to provide at least one control/timing
signal to the TSC, and the reference voltage is synchronously
related to the at least one control/timing signal.
3. The touch data generator of claim 2, wherein the gain of the
amplifier is about one plus the ratio of the touch capacitance and
a capacitance of the feedback capacitor.
4. The touch data generator of claim 2, further comprising: a
sample and hold circuit configured to receive the output voltage,
and an analog-to-digital converter configured to receive an output
from the sample and hold circuit and generate sensor data related
to the touch capacitance of the sensor input.
5. The touch data generator of claim 2, wherein the capacitive
background noise component is a horizontal parasitic capacitance
arising from operation of the touch screen.
6. The touch data generator of claim 2, wherein the capacitive
background noise component is a vertical parasitic capacitance
arising from operation of the touch screen in relation to an
applied control voltage, and the touch data generator further
comprises a cancellation capacitor connected between the negative
input terminal of the amplifier and a cancellation control
voltage.
7. The touch data generator of claim 6, wherein the cancellation
control voltage is synchronously related to the reference voltage
by a factor controlled within the operation of the TSC to remove
the vertical parasitic capacitance.
8. The touch data generator of claim 2, wherein the capacitive
background noise component comprises a vertical parasitic
capacitance and a horizontal parasitic capacitance arising from
operation of the touch screen, and the touch data generator further
comprises a cancellation capacitor connected between the negative
input terminal of the amplifier and a cancellation control
voltage.
9. The touch data generator of claim 8, wherein the cancellation
control voltage is synchronously related to the reference voltage
by a factor controlled within the operation of the TSC to remove
the capacitive background noise component.
10. The touch data generator of claim 2, wherein the capacitive
background noise component comprise a vertical parasitic
capacitance arising from operation of the touch screen in relation
to an applied control voltage, and a horizontal parasitic
capacitance arising from operation of the touch screen, and the
touch data generator further comprises a cancellation capacitor
connected between the negative input terminal of the amplifier and
a cancellation control voltage.
11. The touch data generator of claim 10, wherein the cancellation
control voltage is synchronously related to the reference
voltage.
12. The touch data generator of claim 2, further comprising: a
signal processor configured to receive the at least one
control/timing signal from the timing controller.
13. The touch data generator of claim 4, further comprising: a
signal processor configured to receive the at least one
control/timing signal from the timing controller, generate a sample
and hold control signal synchronously related to the at least one
control/timing signal, and apply the sample and hold control signal
to the sample and hold circuit to control operation of the sample
and hold circuit.
14. A touch data generator configured for use within a touch screen
controller (TSC) in a touch display device comprising a touch
screen panel, and a display driving circuit (DDI), wherein the
touch data generator comprises: driving and sensing control circuit
detecting a sensor input and passing the detected sense input to an
amplifier, wherein the sensor input comprises a touch capacitance
and a capacitive background noise component; the amplifier
comprises a positive input terminal receiving an alternating
reference voltage, a negative input terminal receiving the sensor
input, an output terminal providing an output voltage, and a
resistance-capacitance (RC) feedback circuit biasing the amplifier,
the amplifier is configured to remove the capacitive background
noise component from the sensor input while amplifying the
reference voltage in response to the touch capacitance, and the DDI
comprises a timing controller configured to provide at least one
control/timing signal to the TSC, such that the reference voltage
is synchronously related to the at least one control/timing
signal.
15. The touch data generator of claim 14, wherein the driving and
sensing circuit comprises a plurality of sense lines respectively
incorporating a sense line switch, wherein each one of the
plurality of sense lines and corresponding sense line switches
forms a sensor input channel, and each sensor input channel is
sequentially switched onto the negative input terminal of the
amplifier.
16. The touch data generator of claim 1, wherein the display
driving circuit is configured to drive a liquid crystal display
panel, a plasma display panel, a light emitting diode display
panel, or an organic light emitting display panel.
17. A method operating a touch screen controller (TSC) in a touch
display device comprising a touch screen panel and a display
driving circuit (DDI), the method comprising: coupling a positive
input terminal of an amplifier to an alternating reference voltage;
coupling a negative input terminal of the amplifier to a driving
and sensing control circuit to receive a sensor input, wherein the
sensor input comprises a touch capacitance and a capacitive
background noise component; and biasing the amplifier with a
resistance-capacitance (RC) feedback circuit to amplify the
reference voltage in response to the touch capacitance while
removing the capacitive background noise component.
18. The method of claim 17, wherein the reference voltage is
synchronously related to at least one control/timing signal
provided to the TSC by the DDI.
19. The method of claim 17, wherein the reference voltage is
amplified with a gain approximately equal to one plus the ratio of
the touch capacitance and a capacitance of a feedback capacitor in
the RC feedback circuit.
20. The method of claim 17, wherein the capacitive background noise
component is at least one of a horizontal parasitic capacitance
arising from operation of the touch screen, and a vertical
parasitic capacitance arising from operation of the touch screen in
relation to an applied control voltage.
21. The method of claim 17, further comprising: coupling a
cancellation capacitor between the negative input terminal of the
amplifier and a cancellation control voltage.
22. The method of claim 21, wherein the cancellation control
voltage is synchronously related to the reference voltage.
23. The method of claim 22, wherein the capacitive background noise
component comprises a horizontal parasitic capacitance arising from
operation of the touch screen and a vertical parasitic capacitance
arising from operation of the touch screen in relation to an
applied control voltage.
24. A touch display device, comprising: a display; a display
driving circuit (DDI) configured to control operation of the
display; a touch screen; a touch screen controller (TSC) configured
to control operation of the touch screen, wherein the TSC comprises
a touch data generator configured to generate sense data
corresponding to sensor input related to user-defined touch data
received via the touch screen, the touch data generator comprising:
an amplifier comprising a positive input terminal receiving an
alternating reference voltage, a negative input terminal receiving
the sensor input, an output terminal providing an output voltage,
and a resistance-capacitance (RC) feedback circuit biasing the
amplifier, wherein the sensor input comprises sensor capacitance
including a touch capacitance and a capacitive background noise
component, and the amplifier is configured to remove the capacitive
background noise component from the sensor input while amplifying
the reference voltage in response to the touch capacitance.
25. The touch display device of claim 24, wherein the DDI comprises
a timing controller configured to provide at least one
control/timing signal to the TSC, and the reference voltage is
synchronously related to the at least one control/timing
signal.
26. The touch display device of claim 25, wherein the gain of the
amplifier is about one plus the ratio of the touch capacitance and
a capacitance of a feedback capacitor in the RC feedback
circuit.
27. The touch display device of claim 25, wherein the touch data
generator further comprises a sample and hold circuit configured to
receive the output voltage, and an analog-to-digital converter
configured to receive an output from the sample and hold circuit
and generate sensor data corresponding to the touch
capacitance.
28. The touch display device of claim 25, wherein the capacitive
background noise component is a horizontal parasitic capacitance
arising from operation of the touch screen.
29. The touch display device of claim 25, wherein the capacitive
background noise component is a vertical parasitic capacitance
arising from operation of the touch screen in relation to an
applied control voltage, and the touch data generator further
comprises a cancellation capacitor connected between the negative
input terminal of the amplifier and a cancellation control
voltage.
30. The touch display device of claim 29, wherein the cancellation
control voltage is synchronously related to the reference voltage
by a factor controlled within the operation of the TSC to remove
the vertical parasitic capacitance.
31. The touch display device of claim 25, wherein the display is a
liquid crystal display panel, a plasma display panel, a light
emitting diode display panel, or an organic light emitting display
panel.
32-65. (canceled)
Description
PRIORITY CLAIM
[0001] A claim for priority under 35 U.S.C. .sctn.119 is made to
Korean Patent Application No. 10-2008-0107294 filed on Oct. 30,
2008, Korean Patent Application No. 10-2009-0023042, filed on Mar.
18, 2009, and Korean Patent Application No. 10-2009-0099318, filed
on Oct. 19, 2009, the entirety of which are hereby incorporated by
reference.
BACKGROUND
[0002] The inventive concepts relate to a touch controller, and
more particularly, to a touch controller having increased sensing
sensitivity, and a display driving circuit and a display device and
system including the touch controller.
[0003] As a consequence of the need for thinner and lighter display
devices, flat display devices have replaced cathode ray tubes
(CRTs). Examples of flat display devices are LCDs, field emission
displays (FEDs), organic light emitting diodes (OLEDs), and plasma
display panels (PDPs).
[0004] In general, such flat display devices include a plurality of
pixels that are arranged in a matrix in order to display an image.
In an LCD which is an example of flat display device, a plurality
of scan lines that deliver a gate selection signal and a plurality
of data lines that deliver gratin data are arranged to intersect
one another, whereby a plurality of pixels are formed where the
scan lines and the data lines intersect one another.
[0005] A touch screen panel, e.g., a capacitive touch screen panel,
includes a plurality of sensing units. If a user touches a screen
of the touch screen panel with his/her finger or a touch pen, a
capacitance value of a corresponding sensing unit changes. In
general, the touch screen panel is attached to an upper part of a
flat display device, and when a user's finger or a touch pen
approaches or touches the sensing units of the touch screen panel,
the capacitance value of a corresponding sensing unit is provided
to a touch screen processor. The touch screen processor senses a
capacitance of the corresponding sensing unit by using the sensing
lines, and determines whether the touch screen panel is touched
with a user's finger or a touch pen or determines the touched
location on the touch screen panel. The sensing units may be
included in a display panel in order to minimize a reduction in
yield and brightness and an increase in the thickness of the
display panel, caused when the touch screen panel is attached to
the display panel.
[0006] FIG. 1 is a block diagram of a general touch screen system
10. Referring to FIG. 1, the touch screen system includes a touch
screen panel 11 having a plurality of sensing units and a signal
processor 12 that senses and processes a change in a capacitance of
each of the sensing units and then generates touch data.
[0007] The touch screen panel 11 includes a plurality of sensing
units disposed in a row and a plurality of sensing units disposed
in a column. Referring to FIG. 1, the touch screen panel 11
includes a plurality of rows in which a plurality of sensing units
are disposed, in which a plurality of sensing units are arranged in
each of the rows. The plurality of sensing units arranged in each
of the rows are electrically connected to one another. Also, the
touch screen panel 11 includes a plurality of columns in which a
plurality of sensing units are disposed, in which a plurality of
sensing units are arranged in each of the columns. The plurality of
sensing units arranged in each of the columns are electrically
connected to one another.
[0008] The signal processor 12 generates the touch data by sensing
a change in the capacitance of each of the plurality of sensing
units of the touch screen panel 11. For example, signal processor
12 may sense a change in the capacitance of each of the plurality
of sensing units in the plurality of rows and in the plurality of
columns in order to determine whether the touch screen panel 11 is
touched with a user's finger or a touch pen, or to determine the
touched location on the touch screen panel 11.
[0009] However, the plurality of sensing units of the touch screen
panel 11 contain a parasitic capacitance component. Such a
parasitic capacitance component may be classified into a horizontal
parasitic capacitance component generated between a plurality of
sensing units and a vertical parasitic capacitance component
generated between a sensing unit and a display panel. If the whole
parasitic capacitance has a large value, a change in the
capacitance of a sensing unit touched by a user's finger or a touch
pen has a relatively small value, compared to the value of the
whole parasitic capacitance. The closer the user's finger or the
touch pen approaches the sensing unit, the greater the capacitance
value of the sensing unit. However, when the sensing unit has a
large parasitic capacitance value, the sensing sensitivity of the
sensing unit is lowered. Also, a change in an electrode voltage
VCOM applied onto the display panel may cause a sensing noise to
occur during the touching of the sensing unit through the vertical
parasitic capacitance component.
[0010] In addition, the performance of the touch screen system 11
may be affected by various noise factors which are generated in an
undesirable environment. Examples of the various noise factors are
an electromagnetic noise in the air, a skin accumulated noise, and
a noise generated in the touch screen system 10. Such noises may
degrade the sensing sensitivity of the touch screen system 10.
SUMMARY
[0011] The inventive concept provides a touch controller in which a
sensing unit is affected less by a parasitic capacitance component
and a noise, and a display driving circuit and a display device and
system including the touch controller.
[0012] According to an aspect of the inventive concept, there is
provided a touch controller that includes a touch data generator
connected to a plurality of sensing lines, the touch data generator
sensing a change in capacitance of a sensing unit connected to each
of the sensing lines and generating touch data by processing a
sensing signal indicative of a sensed change in the capacitance,
responsive to a control signal; and a signal processor controlling
a timing of generating the touch data responsive to at least one
piece of timing information for driving a display panel as provided
from a timing controller, the signal processor providing either the
timing information or a signal generated from the timing
information as the control signal to the touch data generator.
[0013] According to another aspect of the inventive concept, there
is provided a display driving circuit including a display panel
driving circuit unit including a timing controller generating at
least one piece of timing information for driving a display panel;
and a touch controller disposed to sense whether a touch screen
panel is touched, the touch controller generating a sensing signal
by sensing a change in capacitance of a sensing unit on the touch
screen panel and processing the sensing signal, the touch
controller including a touch data generator generating the sensing
signal by sensing the change in the capacitance of the sensing unit
via a sensing line, and generating touch data by processing the
sensing signal, responsive to a control signal, and a signal
processor controlling a timing of generating the touch data
responsive to the timing information from the timing controller and
supplying either the timing information or a signal generated from
the timing information as the control signal to the touch data
generator.
[0014] According to another aspect of the inventive concept, there
is provided a display panel including a display panel displaying an
image corresponding to received image data; a touch screen panel
having a plurality of sensing units, a capacitance value of each of
the sensing units varies according to a touching operation; a
display panel driving circuit unit connected to the display panel
to drive the display panel, the display panel driving circuit unit
including a timing controller for generating timing information
related to a displaying operation; and a touch controller connected
to the touch screen panel to sense whether the touch screen panel
is touched, the touch controller generating touch data based on the
result of the sensing and controlling a timing of generating the
touch data according to the timing information.
[0015] According to another aspect of the inventive concept, there
is provided a touch controller including a voltage reading circuit
reading first voltages from a plurality of sensing units connected
to a plurality of sensing lines, respectively; a first
amplification circuit offsetting influences in the read first
voltages caused by a capacitance component generated in each of the
plurality of sensing units, amplifying the resultant first
voltages, and then outputting second voltages, and an integration
circuit integrating the second voltages.
[0016] According to another aspect of the inventive concept, there
is provided a display device including a panel unit including a
plurality of sensing units performing a touch screen operation; a
display driving circuit unit receiving at least one piece of first
timing information from an external host, and generating image data
to display an image on the panel unit; and a touch controller
connected to the plurality of sensing units to sense a change in
capacitances of the plurality of sensing units, the touch
controller generating touch data from at least one selected from
the at least one piece of first timing information and a plurality
of pieces of timing information generated by the display driving
circuit unit.
[0017] According to another aspect of the inventive concept, there
is provided a display system including a host controller; a panel
unit including a plurality of sensing units performing a touch
screen operation; a display driving unit receiving at least one
piece of first timing information from the host controller, and
generating image data to display an image on the panel unit; and a
touch controller connected to the plurality of sensing units to
sense a change in capacitances of the plurality of sensing units,
the touch controller generating touch data based on at least one of
the first timing information and timing information generated by
the display driving circuit unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Exemplary embodiments of the inventive concept will be more
clearly understood from the following detailed description taken in
conjunction with the accompanying drawings in which:
[0019] FIG. 1 is a block diagram of a general touch screen panel
system;
[0020] FIG. 2A illustrates a parasitic capacitance component
generated in each of a plurality of sensing units of a touch screen
panel according to an embodiment of the inventive concept;
[0021] FIG. 2B is a graph showing a change in the capacitance of a
sensing unit illustrated in FIG. 2A when the sensing unit is
touched;
[0022] FIG. 2C is a graph showing a change in the capacitance of a
sensing unit illustrated in FIG. 2A when a sensing unit is touched
and a noise is generated;
[0023] FIGS. 3A, 3B, and 3C are block diagrams of a touch
controller according to embodiments of the inventive concept;
[0024] FIGS. 4A and 4B are waveform diagrams of various signals for
generating the control signal ctrl illustrated in FIGS. 3A to 3C,
according to embodiments of the inventive concept;
[0025] FIGS. 5A, 5B, 6A, 6B, 7A, 7B and 8A-8D are circuit diagrams
and graphs illustrating various embodiments of a touch data
generator according to the inventive concept;
[0026] FIG. 9A and FIG. 9B are block and circuit diagrams of a
touch data generator according to embodiments of the inventive
concept;
[0027] FIG. 9C is a circuit diagram of an integration circuit that
is another embodiment of an integration circuit illustrated in FIG.
9A according to the inventive concept;
[0028] FIG. 9D is a waveform diagram illustrating an input signal
Vin and a timing of turning on the switches SW1 to SWn of FIG. 9B
according to an embodiment of the inventive concept;
[0029] FIG. 9E is a waveform diagram of various signals supplied to
the touch controller of FIG. 9B according to an embodiment of the
inventive concept;
[0030] FIG. 9F is a timing diagram illustrating the operation of
the integration circuit of FIG. 9B according to an embodiment of
the inventive concept;
[0031] FIG. 9G is a graph showing a variation in an integration
voltage of the integration circuit of FIG. 9B according to
embodiment of the inventive concept;
[0032] FIG. 10A is a circuit diagram of another embodiment of the
integration circuit included in the touch data generator of FIG.
9B, according to the inventive concept;
[0033] FIG. 10B is a waveform diagram of an output voltage Vout and
the voltage reference signal Vref used in the integration circuit
of FIG. 10A, and an input signal Vin, according to an embodiment of
the inventive concept;
[0034] FIG. 11 is a block diagram of a touch controller according
to another embodiment of the inventive concept;
[0035] FIG. 12A is a block diagram of a general LCD that includes a
plurality of touch controllers according to an embodiment of the
inventive concept;
[0036] FIG. 12B is a block diagram of a general LCD that includes a
touch controller according to another embodiment of the inventive
concept;
[0037] FIG. 13 is a block diagram of an integrated circuit (IC), in
which a touch controller and a display driving unit are integrated
together, according to an embodiment of the inventive concept;
[0038] FIGS. 14A and 14B illustrate an interrelation between a
touch controller and a display driving unit as illustrated in FIG.
13.
[0039] FIGS. 15A to 15C illustrate embodiments of a printed circuit
board (PCB) structure of a display device that includes a touch
panel, according to the inventive concept;
[0040] FIG. 15D illustrates the panel structure of the display
device illustrated in FIG. 15A, 15B, or 15C, according to an
embodiment of the inventive concept;
[0041] FIGS. 16A to 16C illustrate embodiments of a PCB structure
of a display device 800, in which a touch panel and a display panel
are united together, according to the inventive concept;
[0042] FIG. 16D illustrates the panel structure of the display
device illustrated in FIG. 16A, 16B, or 16C, according to another
embodiment of the inventive concept;
[0043] FIGS. 17A and 17B illustrate the structure of a
semiconductor chip that includes a touch controller and a display
driving circuit unit, and the structure of an FPCB according to
embodiments of the inventive concept; and
[0044] FIGS. 18A and 18B illustrate embodiments of a display device
having a semiconductor chip in which a touch controller and a
display driving circuit are included, according to the inventive
concept.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0045] Hereinafter, exemplary embodiments of the inventive concept
will be described in detail with reference to the accompanying
drawings. Like reference numerals denote like elements throughout
the drawings.
[0046] FIG. 2A illustrates a parasitic capacitance component
generated in each of a plurality of sensing units SU of a touch
screen panel 21 according to an embodiment of the inventive
concept. FIG. 2B is a graph showing a change in the capacitance of
a sensing unit SU illustrated in FIG. 2A when the sensing unit is
touched. FIG. 2C is a graph showing a change in the capacitance of
a sensing unit SU illustrated in FIG. 2A when the sensing unit is
touched and a noise is generated.
[0047] Referring to FIG. 2A, the touch screen panel 21 includes the
plurality of sensing units SU. The plurality of sensing units SU
may be arranged near or on a display panel 22 that displays an
image. For example, the reference numeral `22` may denote an upper
plate of a display panel to which a predetermined electrode voltage
VCOM is applied. The display panel having the upper plate 22 may be
a liquid crystal display (LCD) panel, to which the electrode
voltage VCOM may be applied as a common electrode voltage. If the
display panel is an organic light-emitting display panel, a cathode
electrode having a direct-current (DC) voltage may be applied to an
upper plate thereof.
[0048] The touch screen panel 21 includes a plurality of sensing
units SU connected to a plurality of sensing lines arranged in a
row (in an x-axis direction) and a plurality of sensing units SU
connected to a plurality of sensing lines arranged in a column (in
an y-axis direction). If a user's finger or a touch pen approaches
or touches any of the sensing units SU, a capacitance value of the
particular sensing unit SU is changed. Whether the touch screen
panel 21 is touched, and the touched location on the touch screen
panel 21, may be determined by generating a sensing signal by
sensing a change in the capacitance value of each of the sensing
units by using the plurality of sensing lines and then processing
the sensing signal.
[0049] Parasitic capacitance components are present due to an
arrangement of the plurality of sensing units SU. For example, the
parasitic capacitance components include a horizontal parasitic
capacitance component Ch generated between adjacent sensing units
and a vertical parasitic capacitance component Cv generated between
a sensing unit and the display panel 22. If a parasitic capacitance
value is greater than the value of a capacitance component
generated when a user's finger or a touch pen approaches or touches
a sensing unit, even when the capacitance value of the sensing unit
is changed by touching the sensing unit, the sensing sensitivity of
the touching is lowered.
[0050] Referring to FIG. 2B, the sensing unit SU contains a basic
capacitance component Cb including a parasitic capacitance
component, and a capacitance value of the sensing unit SU is
changed when an object, e.g., a user's finger or a touch pen,
approaches or touches the sensing unit SU. For example, when a
conductive object approaches or touches the sensing unit SU, the
capacitance value of the sensing unit SU increases. Referring to
FIG. 2B, in a section A, the capacitance value of the sensing unit
SU is Cb since the conductive object does not approach the sensing
unit SU; in a section B, the conductive object touches the sensing
unit SU; and in a section C, the conductive object approaches the
sensing unit SU. Referring to FIG. 2B, the capacitance value of Cb
may increase by a degree Csig when the conductive object touches
the sensing unit SU and may increase by a degree Csig' that is less
than the degree Csig when the conductive object approaches the
sensing unit SU.
[0051] As illustrated in FIG. 2C, the capacitance value of the
sensing unit SU may be affected greatly when various noises are
present. In this case, a processor or controller (not shown) cannot
determine precisely whether an object touches the sensing unit SU
and the touched location on the sensing unit SU by simply checking
whether the capacitance value of the sensing unit SU increases or
decreases, thereby greatly degrading the sensing sensitivity of a
touch screen device.
[0052] FIGS. 3A, 3B, and 3C are block diagrams of a touch
controller 110 according to embodiments of the inventive concept.
Here, a display driving circuit 120 that drives a display panel
(not shown) to display an image and a host controller 130 that
controls the overall operations of the touch controller 110, are
further illustrated in order to help explain the operation of the
touch controller 110.
[0053] Referring to FIG. 3A, the touch controller 110 may include a
signal processor 111 and a touch data generator 112. The display
driving circuit 120 may include a timing controller 121 that
controls an image to be displayed on the display panel, a gate
driver 122, and a source driver 123.
[0054] The signal processor 111 controls the overall operations of
internal circuits of the touch controller 110 in relation to a
touch screen operation. Although not shown, the touch data
generator 112 is electrically connected to a plurality of sensing
units SU via sensing lines and generates a sensing signal by
sensing a change in the capacitance of each of the plurality of
sensing units SU when they are touched. Also, the touch data
generator 112 generates and outputs touch data data by processing
the sensing signal. The signal processor 111 or the host controller
130 performs a logic operation based on the touch data data, and
determines whether a touch screen (not shown) is touched and the
touched location on the touch screen.
[0055] The touch controller 110 receives at least one piece of
timing information Timing info for driving a display panel (not
shown), and may use the timing information Timing info in order to
generate the touch data data. The timing information Timing info
may be generated by either the timing controller 121 included in
the display driving circuit 120 or directly by the host controller
130. FIG. 3A illustrates that the timing information Timing info is
generated by the timing controller 121 and the touch controller 110
receives the timing information Timing info from the timing
controller 121. The signal processor 111 receives the at least one
piece of timing information Timing info and transmits a control
signal ctrl based on the at least one piece of timing information
Timing info to the touch data generator 112.
[0056] The control signal ctrl may be generated based on a wave
form of the timing information Timing info. The control signal ctrl
may be generated directly by the timing controller 121 and provided
to the signal processor 111, or the signal processor 111 may
generate the control signal ctrl from the timing information Timing
info received from the timing controller 121. Also, as described
above, the host controller 130 may generate the timing information
Timing info, and similarly, the control signal ctrl may be
generated by the host controller 130 and provided to the touch
controller 110. If the host controller 130 generates the control
signal ctrl, the control signal ctrl may be supplied to the signal
processor 111 or may be supplied directly to the touch data
generator 112. Hereinafter, it is assumed that the signal processor
111 generates the control signal ctrl as illustrated in FIGS. 3A to
3C.
[0057] The timing controller 121 generates at least one signal for
controlling a timing of displaying an image. For example, the
timing controller 121 may receive a vertical synchronization signal
Vsync and a horizontal synchronization signal Hsync directly from
the external host controller 130, or may generate the vertical
synchronization signal Vsync and the horizontal synchronization
signal Hsync based on a data enable signal (not shown) received
from the host controller 130. Also, the timing controller 121 may
control generation of a common electrode voltage, e.g., an
electrode voltage VCOM, and generation of a gate line signal by
generating at least one timing signal.
[0058] The signal processor 111 generates the control signal ctrl
in synchronization with the at least one piece of timing
information Timing info received from the timing controller 121,
and supplies the control signal ctrl to the touch data generator
112 in order to control a timing of generating the touch data data.
That is, if a voltage applied to the display panel, e.g., a common
electrode voltage applied to an upper plate of the display panel,
changes, then a noise may be contained in a sensing signal.
Accordingly, the signal processor 111 controls the touch data data
to be generated during a period when the voltage is in a stable
state.
[0059] The touch controller 110 and the display driving circuit 120
may be integrated in one semiconductor chip. That is, in an
embodiment of the inventive concept, the touch controller 110
receives at least one piece of timing information Timing info from
the display driving circuit 120 and performs an operation in
synchronization with the timing information Timing info, the timing
information Timing info may be transmitted via a wire
interconnecting the touch controller 110 and the display driving
circuit 120 in one semiconductor chip.
[0060] FIGS. 3B and 3C are block diagrams illustrating various ways
of generating the touch data data illustrated in FIG. 3A according
to embodiments of the inventive concept. FIG. 3B illustrates a case
where the touch controller 110 receives information control/timing
related to a timing of driving a display panel (not shown) directly
from the host controller 130. In this case, the timing controller
121 may skip generating timing information Timing info based on the
information control/timing received from the host controller 130
and supplying it to the touch controller 110. The signal processor
111 receives the information control/timing from the host
controller 130, generates a control signal ctrl based on the
information control/timing, and supplies the control signal ctrl to
the touch data generator 112.
[0061] FIG. 3C illustrates a case where information generated by a
timing controller 121 and information generated by the host
controller 130 are multiplexed into timing information Timing info
and the timing information Timing info is supplied to the touch
controller 110. To this end, a selection unit 140 that allows a
signal to be selectively supplied may be disposed between the touch
controller 110 and the display driving circuit 120 illustrated in
FIG. 3C. For example, the selection unit 140 may be embodied as a
multiplexer (MUX). The selection unit 140 may be disposed between
the touch controller 110 and the display driving circuit 120 or may
be disposed before a signal processor 111 included in the touch
controller 110. The selection unit 140 selectively outputs the
information generated by the timing controller 121 or the
information generated by the host controller 130, in response to a
predetermined control signal (not shown). In this case, if the
display driving circuit 120 operates in a normal mode, the
information generated by the timing controller 121 may be supplied
to the touch controller 110. If the display driving circuit 120
enters a power down mode, e.g., a sleep mode, the information
generated by the host controller 130 may be supplied to the touch
controller 110.
[0062] FIG. 4A is a waveform diagram of various signals for
generating the control signal ctrl illustrated in FIGS. 3A to 3C,
according to an embodiment of the inventive concept. Referring to
FIG. 4A, a horizontal synchronization signal Hsync is activated
after a vertical synchronization signal Vsync is activated. A logic
level of a common electrode voltage, e.g., an electrode voltage
VCOM, changes in synchronization with the horizontal
synchronization signal Hsync. The control signal ctrl may be
generated from at least one of various types of timing information,
e.g., the vertical or horizontal synchronization signal Hsync or
Vsync, timing information for generating a common electrode
voltage, DotCLK information). A timing of generating touch data
data is controlled according to a timing of activating the control
signal ctrl, and a noise may be prevented from being generated in
the touch data data, caused by a change in an electrode applied to
a display panel.
[0063] FIG. 4B is a waveform diagram of various signals for
generating the control signal ctrl illustrated in FIGS. 3A to 3C,
according to another embodiment of the inventive concept. Referring
to FIG. 4B, a porch section in which a horizontal synchronization
signal Hsync is not activated, is present before and after a
section in which a vertical synchronization signal Vsync is
activated. A common electrode voltage applied to a display panel is
controlled not to change during the porch section. In this case, it
is possible to reduce a noise generated due to a change in a
voltage applied to a display panel by activating the control signal
ctrl in the porch section of the vertical synchronization signal
Vsync.
[0064] FIGS. 5A to 8D are circuit diagrams and graphs illustrating
various embodiments of a touch data generator according to the
inventive concept. In detail, FIGS. 5A to 8D illustrate methods of
reducing influences caused by a vertical or horizontal parasitic
capacitance components present in a sensing unit by using an
amplification circuit, according to embodiments of the inventive
concept.
[0065] Specifically, FIG. 5A is a circuit diagram of a touch data
generator 210A, such as the touch data generator 112 of FIG. 3A,
according to an embodiment of the inventive concept. FIG. 5B is a
graph showing frequency characteristics of an amplifier AMP
included in the touch data generator 210A of FIG. 5A according to
an embodiment of the inventive concept. Referring to FIG. 5A, the
touch data generator 210A includes an amplification circuit 211A
that is connected to a sensing unit SU and generates a sensing
signal Vout corresponding to a change in the capacitance of the
sensing unit SU. The touch data generator 210A may further include
a signal output unit 212A that receives the sensing signal Vout and
outputs the sensing signal Vout in response to a control signal
ctrl, and an analog-to-digital converter (ADC) 213A that receives
an analog signal from the signal output unit 212A and converts the
analog signal into a digital signal. The signal output unit 212A
may be a sample/hold circuit that retains the sensing signal Vout
and outputs the sensing signal Vout in response to the control
signal ctrl.
[0066] The amplification circuit 211A includes at least one
amplifier AMP. Although not shown, the at least one amplifier AMP
may include a plurality of amplifiers respectively connected to a
plurality of sensing lines arranged in a plurality of rows and
columns in a touch screen panel. Otherwise, the amplifier AMP may
be constructed such that the amplifier AMP is switched to be
connected with one of the plurality of sensing lines, so that the
amplifier AMP may be shared by the plurality of sensing lines. For
convenience of explanation, FIG. 5A illustrates a case where one
amplifier AMP is connected to one sensing line.
[0067] A first input terminal, e.g., an inversion input terminal
(-) of the amplifier AMP is connected to the sensing unit SU in
order to sense a change in the capacitance of the sensing unit SU.
As illustrated in FIG. 5A, the capacitance of the sensing unit SU
may include a parasitic capacitance component, e.g., a horizontal
parasitic capacitance component Ch, and a capacitance variation
Csig caused when the sensing unit SU is touched.
[0068] An input signal Vin having a predetermined frequency is
supplied to a second input terminal of the amplifier AMP. The input
signal Vin may be a signal, e.g., a square-wave or sinusoidal-wave
signal having a predetermined pulse cycle. The logic level and
frequency of the input signal Vin may be adjusted appropriately.
The frequency of the input signal Vin may fall within a pass band
of the amplifier AMP having high-pass filtering characteristics.
Although not shown, a direct-current (DC) voltage (e.g., ground
voltage) signal may be supplied to second input terminals of
amplifiers connected to the sensing lines other than the sensing
line that performs a sensing operation. Thus, referring to FIG. 5A,
one node of the horizontal parasitic capacitance component Ch is
represented as being applied to a ground voltage.
[0069] A capacitor Cf may be connected between the first input
terminal and an output terminal of the amplifier AMP, and a
predetermined resistor Rf may further connected between the first
input terminal and the output terminal of the amplifier AMP to be
parallel to the capacitor Cf. Accordingly, the amplifier AMP may
act as a high-pass filter having a predetermined voltage gain.
[0070] The amplifier AMP generates the sensing signal Vout, the
voltage level of which varies according to a change in the
capacitance of the sensing unit SU. FIG. 5B illustrates the
pass-band characteristics and voltage gain of the amplifier AMP. As
illustrated in FIG. 5A, the frequency of the input signal Vin may
be greater than
1 2 .pi. C f R f . ##EQU00001##
If the frequency of the input signal Vin falls within the pass band
of the amplifier AMP, the gain of the amplifier AMP is calculated
by a numerical formula,
20 log 10 ( 1 + C h + .DELTA. C C f ) . ##EQU00002##
[0071] When as expressed in the above equation, the capacitance of
the sensing unit SU changes when the sensing unit SU is touched,
the logic level of the sensing signal Vout generated by the
amplifier AMP is changed according to the change in the capacitance
of the sensing unit SU. The amplifier AMP generates the sensing
signal Vout corresponding to the capacitance value of the sensing
unit SU in an analog manner. Whether the touch screen panel is
touched, or the touched location on the touch screen panel, may be
determined by sensing a change in the voltage of the sensing signal
Vout.
[0072] The control signal ctrl may be generated using at least one
piece of timing information and may be used in order to generate
touch data data using the sensing signal Vout. The signal output
unit 212A receives the sensing signal Vout from the amplification
circuit 211A, retains the sensing signal Vout, and supplies the
sensing signal Vout to the ADC 213A in response to the activated
control signal ctrl. The ADC 213A generates the touch data data by
converting the sensing signal Vout that is an analog signal into a
digital signal, and supplies the converted result to the
outside.
[0073] As described above, whether a touch screen is touched, and
the touched location on the touch screen, may be determined by
performing a sensing operation and generating the touch data data.
Also, generation of a noise caused by a change in a voltage applied
to a display panel may be minimized by controlling a timing of
generating the touch data data in response to the control signal
ctrl.
[0074] However, if the value of the parasitic capacitance component
Ch between a plurality of sensing units SU is increased, then the
gain of the amplifier AMP is also increased. In this case, the
capacitor Cf connected between the first input terminal and the
output terminal of the amplifier AMP should have a large value in
order for the level of the voltage output from the amplifier AMP to
be in a predetermined range (e.g., within the voltage range in
which a system can operate). However, if the capacitance of the
capacitor Cf has a large value, a change in the voltage of the
amplifier AMP, i.e., a ratio Csig/Cf of the capacitance variation
Csig to the value of the capacitor Cf, when the touch screen panel
is touched becomes small, thereby lowering the sensing sensitivity
of the touching. The sensing lines of the touch screen panel may be
formed of a transparent conductive material, e.g., an indium-tin
oxide (ITO). Thus, when the distances between sensing units SU are
large, the sensing lines become conspicuous, and thus, the
distances between the sensing units SU should be determined to be
small. However, if the distances between the sensing units are
small, the value of the horizontal parasitic capacitance component
Ch generated in each of the sensing units becomes greater, and
thus, sensing sensitivity of touching may be degraded. Various
embodiments of a touch data generator capable of improving sensing
sensitivity by reducing a parasitic capacitance component according
to the inventive concept will now be described.
[0075] Referring to FIG. 6A, a touch data generator 210B includes
an amplification circuit 211B that generates a sensing signal Vout
corresponding to a change in the capacitance of a sensing unit SU.
The touch data generator 210B may further include a signal output
unit 212B that receives the sensing signal Vout and outputs it
according to a control signal ctrl, and an ADC 213B that generates
touch data data by converting the sensing signal Vout that is an
analog signal received from the signal output unit 212B into a
digital signal.
[0076] The amplification circuit 211B of FIG. 6A may increase
sensing sensitivity by reducing influences caused by a horizontal
capacitance component Ch generated in the sensing unit SU (a
parasitic capacitance component between a plurality of sensing
units SU). To this end, a ground voltage or a DC voltage is not
applied to an amplifier AMP corresponding to a sensing line
adjacent to a sensing line via which a sensing operation is
performed, but rather an input signal Vin is applied to a second
input terminal, e.g., a (+) terminal, of an amplifier Amp
corresponding to a sensing line adjacent a sensing line via which a
sensing operation is performed.
[0077] That is, if a first electrode and second electrode of a
horizontal parasitic capacitor act as a first sensing line via
which a sensing operation is performed and a second sensing line
adjacent to the first sensing line, respectively, then the same
voltage is applied to the first sensing line and the second sensing
line. In this case, the horizontal parasitic capacitance component
Ch is removed from the numerical formula,
20 log 10 ( 1 + C h + .DELTA. C C f ) ##EQU00003##
of calculating the gain of the amplifier AMP.
[0078] Although FIG. 6A illustrates the second electrode of the
horizontal parasitic capacitor is connected directly to the
corresponding second input terminal of the amplifier AMP, the
inventive concept is not limited thereto. Unlike as illustrated in
FIG. 5A, in the current embodiment of FIG. 6A, the input signal Vin
is commonly supplied to second input terminals, i.e., (+) input
terminals, of a plurality of amplifiers AMP. When the input signal
Vin is supplied to the second input terminal, i.e., the (+) input
terminal, of the amplifier AMP, a voltage of the first input
terminal, i.e., a (-) input terminal, of the amplifier AMP becomes
equal to the voltage of the second input terminal, i.e., the (+)
input terminal. That is, since the input signal Vin is also
supplied to the second input terminal of the amplifier AMP
connected to the adjacent sensing line, a voltage of the adjacent
sensing line also becomes equal to the value of the input signal
Vin. For this reason, the voltage the first sensing line via which
a sensing operation is performed is equal to the voltage of the
second sensing line adjacent to the first sensing line, and thus,
the gain of the amplifier AMP is not related to the value of the
horizontal parasitic capacitance component Ch. That is, the same
voltage Vin is applied to sensing lines adjacent to each other, in
order to reduce the influences caused by a horizontal parasitic
capacitance component in the sensing unit.
[0079] FIG. 6B is a graph showing the frequency characteristics of
the amplifier AMP of FIG. 6A according to an embodiment of the
inventive concept. As described above, the frequency of an input
signal Vin is determined to fall within a pass band of the
amplifier AMP. That is, the frequency of the input signal Vin may
be determined to be greater than
1 2 .pi. C f R f ##EQU00004##
illustrated in FIG. 6B. Also, the gain of the amplifier AMP of FIG.
6A is equal to
20 log 10 ( 1 + Csig C f ) . ##EQU00005##
That is, the gain of the amplifier AMP is not related to the value
of a horizontal parasitic capacitance component Ch connected to a
corresponding sensing line.
[0080] Even if the value of a horizontal parasitic capacitance
component Ch present in a sensing line of a touch screen panel
increases, the gain of the amplifier AMP is not changed. Thus, the
capacitance value of the capacitor Cf of FIG. 6A does not need to
be increased so that the gain of the amplifier AMP falls within a
predetermined range. Accordingly, it is possible to appropriately
increase the ratio Csig/Cf that represents sensing sensitivity and
to improve the sensing sensitivity of the capacitance variation
Csig when touching is made.
[0081] FIGS. 7A and 7B are circuit diagrams illustrating in detail
the touch data generator 210B of FIG. 6A. For convenience of
explanation, the signal output circuit 212B and the ADC 213B
included in the touch data generator 210B are not illustrated
here.
[0082] As illustrated in FIG. 7A, the touch data generator 210B may
include a plurality of amplifiers, e.g., a first amplifier AMP1 to
a third amplifier AMP3, which are connected to a plurality of
sensing lines, e.g., a first sensing line SL1 to a third sensing
line SL3, respectively. The first and third amplifiers AMP1 to AMP3
sense a change in the capacitances of sensing units (not shown)
corresponding thereto and generate first to third sensing signals
Vout1 to Vout3 corresponding to the sensed changes, respectively.
First to third capacitors Cf1 to Cf3 and first to third resistors
Rf1 to Rf3 may be connected in parallel between first input
terminals, e.g., (-) input terminals, and output terminals of the
respective first to third amplifiers AMP1 to AMP3.
[0083] Also, an input signal Vin having a predetermined frequency
is commonly supplied to the second input terminal, e.g., the (+)
input terminals) of the first to third amplifiers AMP1 to AMP3. The
first to third amplifiers AMP1 to AMP3 correspond to and are
connected to the first to third sensing lines SL1 to SL3,
respectively. Thus, the first to third amplifiers AMP1 to AMP3
sense a change in the capacitances of the corresponding first to
third sensing lines SL1 to SL3 and generate the first to third
sensing signals Vout1 to Vout3, respectively. In FIG. 7A,
horizontal parasitic capacitance components Ch1 to Ch3 are
generated between the first to third sensing lines SL1 to SL3.
[0084] The operation of the touch data generator 210B will now be
described assuming that a sensing operation is performed using the
second sensing line SL2. The first input terminal, e.g., the (-)
input terminal, of the second amplifier AMP2 is connected to the
second sensing line SL2, and thus, the second amplifier AMP2
generates the second sensing signal Vout2 corresponding to the
capacitance value of a corresponding sensing unit. The input signal
Vin that is supplied to the second amplifier AMP2 is also supplied
to the second input terminals, i.e., the (+) input terminals, of
the first and third amplifiers AMP1 and AMP3. Voltages of the
respective first input terminals, e.g., the (-) input terminals, of
the first and third amplifiers AMP1 and AMP3 become equal to
voltages of the respective second input terminals, e.g., the (+)
input terminals, of the first and third amplifiers AMP1 and AMP3.
Thus, voltages of the first and third sensing lines SL1 and SL3
being respectively connected to the first input terminals, e.g.,
the (-) input terminals, of the respective first and third
amplifiers AMP1 and AMP3 become equal to a voltage of the second
sensing line SL2. Thus, voltages of adjacent sensing lines become
equal to or similar to each other. Accordingly, influences caused
by the horizontal capacitance components Ch1 and Ch2 may be reduced
as illustrated above in FIG. 6B.
[0085] FIG. 7B is a circuit diagram of a touch data generator 210B
designed to perform the operation of the touch data generator of
FIG. 7A, in which one amplifier AMP is shared by first to third
sensing lines SL1 to SL3, according to another embodiment of the
inventive concept. The touch data generator 210B of FIG. 7B may
further include first to third switches SW1 to SW3 that switch
connection of a first input terminal, e.g., an (-) input terminal,
of the amplifier AMP between the first to third sensing lines SL1
to SL3, respectively, so that the first to third sensing lines SL1
to SL3 may be selectively connected to the first input terminal,
e.g., the (-) input terminal, of the amplifier AMP.
[0086] When a sensing operation is performed using the second
sensing line SL2, the second switch SW2 is switched on to connect
the second sensing line SL2 to the first input terminal, e.g., the
(-) input terminal, of the amplifier AMP. Also, the first switch
SW1 connected to the first sensing line SL1 adjacent to the second
sensing line SL2 is switched on to connect the first sensing line
SL1 to a line that transmits an input signal Vin. The third switch
SW3 connected to the third sensing line SL3 adjacent to the second
sensing line SL2 is also switched on to connect the third sensing
line SL3 to the line that transmits the input signal Vin.
[0087] Accordingly, the amplifier AMP senses a capacitance value of
a corresponding sensing unit (not shown) via the second sensing
line SL2 and generates a sensing signal Vout according to the
sensed capacitance value. Since the input signal Vin is supplied to
the first sensing line SL1 and the third sensing line SL3 adjacent
to the second sensing line SL2, a voltage of the second sensing
line SL2 becomes equal to those of the first and third sensing
lines SL1 and SL3. Thus, influences caused by a horizontal
parasitic capacitance component Ch2 are reduced, thereby improving
sensing sensitivity of touching.
[0088] FIGS. 8A to 8C are circuit diagrams respectively
illustrating touch data generators 210C, 210D, and 210E that are
various embodiments of the touch data generator 112 of FIG. 3A, 3B
or 3C, according to the inventive concept. Referring to FIGS. 8A to
8C, the touch data generators 210C, 210D, and 210E further include
an additional capacitor, e.g., a second capacitor Cq, in order to
compensate for a parasitic capacitance component present in a
sensing unit SU. Accordingly, sensing sensitivity may be improved
by removing a horizontal or vertical parasitic capacitance
components present in the sensing unit SU.
[0089] Referring to FIG. 8A, the touch data generator 210C includes
an amplifier AMP having a first input terminal, e.g., a (-) input
terminal, which is connected to a sensing line and a second input
terminal, e.g., a (+) input terminal to which an input signal Vin
is supplied. A first capacitor Cf and a resistor Rf may be
connected in parallel between the first input terminal and an
output terminal of the amplifier AMP.
[0090] The touch data generator 210C may further include the second
capacitor Cq that is connected to the sensing line and has a
predetermined capacitance value. A first electrode of the second
capacitor Cq is connected to the sensing line and a predetermined
voltage signal Vq is applied to a second electrode of the second
capacitor Cq. The polarity of electric charges induced in the
second capacitor Cq is controlled to be opposite to that of
electric charges induced in a parasitic capacitance component Ct
(horizontal and vertical parasitic capacitance components) present
in the sensing unit SU by the capacitance of the second capacitor
Cp and the voltage signal Vq. For example, if electric charges
having a positive (+) polarity, which are induced in a parasitic
capacitor, are supplied to the sensing line, then electric charges
induced in the first electrode of the second capacitor Cq is
controlled to have a negative (-) polarity. Also, if the voltage
signal Vq supplied to the second electrode of the second capacitor
Cq may be synchronized with the input signal Vin supplied to the
second input terminal of the amplifier AMP, and in this case, the
value of the voltage signal Vq may be defined as xVin. Thus, the
gain of the amplifier AMP may be calculated as follows:
gain = 1 + s ( C f + C t + Csig + C q - xC q ) R f 1 + sC f R f . (
1 ) ##EQU00006##
[0091] n equation of calculating the gain of the amplifier AMP in a
high-frequency band may be obtained from Equation (1), as
follows:
gain = C f + C t + Csig + C q - xC q C f . ( 2 ) ##EQU00007##
[0092] As described above, `xC.sub.q` and `C.sub.f+C.sub.t+C.sub.q`
expressed in Equations (1) and (2) may be controlled to be equal to
or similar to each other by adjusting the capacitance value of the
second capacitor Cq and the logic level x of the voltage signal Vq.
If `xC.sub.q` and `C.sub.f+C.sub.t+C.sub.q` are equal to each
other, `C.sub.f+C.sub.t+C.sub.q` and `xC.sub.q` in Equation (2)
offset each other, and thus, the gain of the amplifier AMP may
become `Csig/C.sub.f`. If `xC.sub.q` and `C.sub.f+C.sub.t+C.sub.q`
are similar to each other, sensing sensitivity is improved. That
is, a change in the gain of the amplifier AMP caused by the
parasitic capacitance component Ct may be reduced by adjusting `x`
and `C.sub.q`, thereby improving sensing sensitivity of a
capacitance variation Csig when touching is made. In this case, it
is unnecessary to apply the same voltage to sensing lines adjacent
to the sensing line on which a sensing operation is performed.
[0093] FIG. 8B illustrates a touch data generator 210D capable of
reducing influences caused by interference in a sensing line due to
a change in a voltage applied to a display panel (not shown)
according to another embodiment of the inventive concept. For
example, if a touch screen panel is included in a mobile LCD,
interference may occur due to alternation of an electrode voltage
VCOM applied to an upper plate electrode of a display panel.
[0094] A vertical capacitance component Cv is generated between the
sensing line and the display panel. The vertical capacitance
component Cv influences an output of the amplifier AMP due to
alternation of the electrode voltage VCOM applied to an upper plate
electrode of the display panel alternately. To solve this problem,
the input signal Vin is supplied to the second input terminal of
the amplifier AMP, in synchronization with the electrode voltage
VCOM. If a swing amplitude of the input signal Vin is set to be
less than that of the electrode voltage VCOM, then negative (-)
electric charges are gathered on an upper electrode of a vertical
parasitic capacitor, e.g., an electrode connected to the sensing
line when the input signal Vin is at logic high. In this case,
positive (+) electric charges are gathered on an upper electrode of
the second capacitor Cq by adjusting appropriately a capacitance
value of the second capacitor Cq and a voltage signal Vq, where the
amount of the positive (+) electric charges is equal to or similar
to the amount of the negative (-) electric charges gathered on the
vertical parasitic capacitor. Thus, an output of the amplifier AMP
may be hardly or less affected by the vertical capacitance
component Cv and a variation in the electrode voltage VCOM.
[0095] If the input signal Vin and the voltage signal Vq are
synchronized with the electrode voltage VCOM, then the electrode
voltage VCOM may be expressed as `xVin` and the voltage signal Vq
may be expressed as `yVin`. In this case, the gain of the amplifier
AMP of FIG. 8B may also be expressed as follows:
gain = 1 + s [ ( C f + Csig + ( 1 - x ) C v + ( 1 - y ) C q ) ] R f
1 + sC f R f . ( 3 ) ##EQU00008##
[0096] An equation of calculating the gain of the amplifier AMP in
a high-frequency band be obtained from Equation (3), as
follows:
gain = C f + Csig + ( 1 - x ) C v + ( 1 - y ) C q C f . ( 4 )
##EQU00009##
[0097] As expressed in Equation (4), influences caused by a
variation in the electrode voltage VCOM may be reduced by adjusting
the capacitance value of the second capacitor Cq and the logic
level x of the voltage signal Vq. For example, since the electrode
voltage VCOM has a predetermined level, an output of the amplifier
AMP may not be influenced or be influenced less by a variation in
the electrode voltage VCOM by offsetting or reducing
`C.sub.f+(1-x)C.sub.v+(1-y)C.sub.q` expressed in Equations (3) and
(4), by adjusting the capacitance value of the second capacitor Cq
and the level y of the voltage signal Vq. Accordingly, in addition
to reduction of influences caused by the vertical parasitic
capacitance component, influences caused by an upper plate
electrode voltage VCOM are reduced.
[0098] FIG. 8C is a circuit diagram of a touch data generator 210E
that is another embodiment of the touch data generator 112 of FIG.
3A, 3B, or 3D according to the inventive concept. The touch data
generator 210E of FIG. 8C includes all the features of the touch
data generator 210B illustrated in FIG. 6A and the touch data
generator 210D illustrated in FIG. 8B, and is capable of
effectively reducing a horizontal and vertical parasitic
capacitance component Ch and Cv generated in a sensing unit SU. In
this case, the influences caused by the horizontal parasitic
capacitance component are reduced as described with respect to FIG.
6A, and the influences caused by the vertical parasitic capacitance
component and the voltage VCOM are reduced as described with
respect to FIG. 8B. Also, although not shown, the circuit
constructions of the touch data generators 210B illustrated in
FIGS. 7A and 7B may be applied to the touch data generator 210E of
FIG. 8C in order to effectively reduce the horizontal parasitic
capacitance component Ch generated in the sensing unit SU.
[0099] Referring to FIG. 8C, parasitic capacitance components
generated in the sensing unit SU may include the horizontal
parasitic capacitance component Ch and the vertical parasitic
capacitance component Cv. A voltage of a sensing line via which a
sensing operation is performed is controlled to be equal to a
voltage of a sensing line adjacent to the sensing line via which
the sensing operation is performed in order to reduce the
horizontal parasitic capacitance component Ch generated between
adjacent sensing lines. To this end, an input voltage Vin is
applied to not only an amplifier AMP that performs a sensing
operation on a predetermined sensing line but also a second input
terminal of another amplifier AMP corresponding to a sensing line
adjacent to the predetermined sensing line. Thus, since the
voltages of the predetermined sensing line and the adjacent sensing
line are equal to each other, the amplifier AMP may be affected
less by the horizontal capacitance component Ch. FIG. 8C
illustrates that one electrode of a horizontal parasitic capacitor
is connected directly to a second input terminal of the
corresponding amplifier AMP, but the inventive concept is not
limited thereto. For example, the one electrode of the horizontal
parasitic capacitor may be electrically connected to a first or
second input terminal of an amplifier AMP connected to a sensing
line adjacent to the sensing line connected to the horizontal
parasitic capacitor.
[0100] FIG. 8D is a circuit diagram of a voltage adjustment circuit
221 that adjusts the logic level of a voltage signal Vq applied to
the second capacitor Cq illustrated in FIGS. 8A to 8C, according to
an embodiment of the inventive concept. The voltage adjustment
circuit 221 of FIG. 8D may be included in the touch data generators
210C to 210E of FIGS. 8A to 8C. The voltage adjustment circuit 221
may control the logic level of the voltage signal Vq by using an
input signal Vin, a common voltage Vcm, resistors Rq1 and Rq2, and
so on.
[0101] FIGS. 9A and 9B are block and circuit diagrams of a touch
data generator 310 and 310' according to embodiments of the
inventive concept. FIG. 9C is a circuit diagram of an integration
circuit 313B that is another embodiment of the integration circuit
313 in FIG. 9A, according to the inventive concept. In particular,
compared to the previous embodiments, the touch data generators 310
and 310' illustrated in FIGS. 9A and 9B further include the
integration circuit 313.
[0102] Referring to FIG. 9A, the touch data generator 310 may
include a voltage reading circuit 311, an amplification circuit
312, an integration circuit 313, and an ADC circuit 314.
[0103] Although not shown, the voltage reading circuit 311 reads a
voltage Vread output from each of a plurality of sensing units
connected to a plurality of sensing lines included in a touch
screen panel. For example, the voltage reading circuit 311 may
includes various switches and a buffer for providing an input
signal Vin as illustrated in FIG. 7B.
[0104] Also, the amplification circuit 312 amplifies the voltage
Vread read from the voltage reading circuit 311 and outputs the
result of amplification. The result of amplification output from
the amplification circuit 312 may be supplied to the integration
circuit 313 as a sensing signal Vout. The amplification circuit 312
amplifies the voltage Vread output from the voltage reading circuit
311 so that a change in the capacitance of a sensing unit (not
shown) may be sensed. Also, the amplification circuit 312 may
include at least one amplifier for performing an amplification
operation, and the at least one amplifier may include a plurality
of amplifiers being respectively connected to a plurality of
sensing lines. Alternatively, the at least one amplifier is
switched to be connected with one of the plurality of sensing lines
so that the at least one amplifier may be shared by the plurality
of sensing lines.
[0105] The integration circuit 313 may integrate the sensing signal
Vout received from the amplification circuit 312. As described
above, the sensing signal Vout output from the amplification
circuit 312 may contain a plurality of noise components, and the
noise components may be effectively removed by integrating the
sensing signal Vout by the integration circuit 313. In the current
embodiment, the integration circuit 313 may include various types
of circuits needed to receive and integrate an input signal and
output the result of integration. The integration circuit 313 may
one of various types of integrators, e.g., a switched capacitor
integrator or a Gm-C integrator.
[0106] The ADC circuit 314 may convert an analog voltage VADC_IN
received from the integration circuit 313 into touch data data
which is a digital signal. Although not shown, the touch data data
may be supplied to either a signal processor included in a touch
controller or a host controller outside the touch controller. It is
possible to determine whether the touch screen panel is touched or
a touched location on the touch screen panel by performing an
operation on the touch data data.
[0107] Referring to FIG. 9B, the touch data generator 310' of this
example uses a switched capacitor integration circuit 313A as an
integration circuit. Otherwise, as illustrated in FIG. 9C, a Gm-C
integration circuit 313B may be used as an integration circuit. In
the touch data generator 310 of FIG. 9B, a voltage reading circuit
311 and an amplification circuit 312 operate as described above
with reference to FIG. 9A and thus are not described again here. In
FIG. 9B, a capacitance component Cb generated in each of a
plurality of sensing units denotes a whole capacitance component
that includes horizontal and vertical parasitic capacitance
components.
[0108] Referring to FIG. 9B, one amplification circuit 312 may be
shared by the plurality of sensing units. When a voltage from a
first sensing unit is read according to a switching operation of a
first switch SW1, the remaining sensing units may be connected to
an input signal Vin according to switching operations of a second
switch SW2 to an n.sup.th switch SWn, respectively. Then,
similarly, a voltage of the second sensing unit may be read and the
remaining sensing units may be driven by a driving circuit (e.g., a
buffer included in the voltage reading circuit 311). The input
signal Vin may be a square-wave signal or a sinusoidal-wave having
a predetermined pulse cycle. The logic level or frequency of the
input signal Vin may be adjusted appropriately.
[0109] FIG. 9D is a waveform diagram illustrating an input signal
Vin and a timing of turning on the switches SW1 to SWn of FIG. 9B
according to an embodiment of the inventive concept. The input
signal Vin may be a square-wave signal or a sinusoidal-wave signal
but FIG. 9D illustrates that the input signal Vin is a square-wave
signal. Also, as illustrated in FIG. 9D, the input signal Vin may
have a predetermined rising time and a predetermined falling time.
Also, the switches SW1 to SWn may be sequentially turned on not to
overlap with one another. Periods of time in which the switches SW1
to SWn are respectively turned on may be equal to or greater than
the pulse cycle of the input signal Vin.
[0110] In FIG. 9B, the amplification circuit 312 may output an
output signal Vout, the voltage level of which depends on a change
in the capacitance of a sensing unit. The value of the output
signal Vout of the amplification circuit 312 may be calculated as
follows:
Vout = Vin + sR f [ ( C f + C sig + C b + C q ) Vin - V q C q ] 1 +
sC f R f . ( 5 ) ##EQU00010##
[0111] If in Equation (5), a capacitance component Cb is completely
offset, that is, when (C.sub.b+C.sub.q)Vin-V.sub.qC.sub.q is
satisfied, the relationship between the sensing signal Vout and the
input signal Vin may be defined as follows:
Vout Vin = 1 + sR f ( C f + C sig ) 1 + sR f C f . ( 6 )
##EQU00011##
[0112] When an object touches a touch screen panel, a capacitance
component Csig between the touch screen panel and the object has a
predetermined intensity, and thus, a voltage of the sensing signal
Vout corresponding to the capacitance component Csig may change.
The amplifier AMP1 may output a sensing signal Vout corresponding
to the capacitance value of a sensing unit in an analog manner.
Whether the touch screen panel is touched and a touched location on
the touch screen panel may be determined by sensing a change in the
voltage of the sensing signal Vout, caused when the touch screen
panel is touched.
[0113] A noise may be contained in the sensing signal Vout output
from the amplification circuit 312, and the integration circuit
313A included in a touch controller according to an embodiment of
the inventive concept may reduce influences caused by the noise
effectively. In general, noise has a Gaussian distribution, and
thus, an average of the values of noise components in a
predetermined section may be zero. Thus, it is possible to
effectively remove the noise from an output voltage Vout by using a
predetermined integration circuit.
[0114] The integration circuit 313A may include an operation
amplifier AMP3 in order to perform an integration operation. A
capacitor C2 may be connected between a first input terminal, e.g.,
a negative input terminal, and an output terminal of the operation
amplifier AMP3. A switch RST may also be connected between the
first input terminal and the output terminal of the operating
amplifier AMP3 to be parallel to the capacitor C2.
[0115] Also, a common voltage Vcm may be applied to a second input
terminal, e.g., a positive input terminal, of the operation
amplifier AMP3. The common voltage Vcm may correspond to an
intermediate level of voltage input to the ADC circuit 314.
[0116] Also, a plurality of switches .phi.1 and .phi.2 and a
capacitor C1 may be connected to the first input terminal, e.g.,
the negative input terminal, of the operation amplifier AMP3. An
integration operation may be performed based on switching
operations of the switches .phi.1 and .phi.2 and a charging
operation of the capacitor C1. The output voltage Vout of the
amplification circuit 312 may be supplied to the inside of the
integration circuit 313A via a predetermined buffer.
[0117] FIG. 9E is a waveform diagram of various signals supplied to
the touch controller according to an embodiment of the inventive
concept. A common voltage Vcm having a predetermined level may be
applied, and an input signal Vin and a voltage signal Vq supplied
to a capacitor Cq may have a predetermined frequency and a voltage
having an intermediate level corresponding the common voltage Vcm.
For example, FIG. 9E illustrates a case where the input signal Vin
and the voltage signal Vq are generated in synchronization with a
horizontal synchronization signal HSYNC. The voltage signal Vq may
be controlled using values of the resistors Rq1 and Rq2 connected
to amplifier AMP2, and influences caused by a capacitance component
Cb generated in a sensing unit may be reduced by adjusting the
logic level of the voltage signal Vq.
[0118] FIG. 9F is a timing diagram illustrating the operation of
the integration circuit 313A of FIG. 9B according to an embodiment
of the inventive concept. As illustrated in FIG. 9F, two switches
.phi.1 may be controlled in the same way and the remaining switches
.phi.2 may be controlled in the same way. First, the switches
.phi.1 may be turned on at a time t1, and the capacitor C1 may thus
be charged with the difference between the input signal Vin and the
output voltage Vout.
[0119] While a predetermined voltage is charged in the capacitor
C1, the switches .phi.1 may be turned off and the remaining
switches .phi.2 may be turned on at a time t2. In this case, the
operation amplifier AMP3 may perform an integration operation so
that a voltage of the first input terminal, e.g., a negative input
terminal, of the amplifier AMP3 may follow a voltage of the second
input terminal, e.g., a positive input terminal, thereof. Thus, an
integration voltage VADC_IN may increase or decrease according to
the difference between the output voltage Vout and the input signal
Vin. When the output voltage Vout is entirely integrated, the
result of integration may not fall within the dynamic range of the
ADC circuit 314, and thus, according to an embodiment of the
inventive concept, a voltage `Vout-Vin` may be integrated according
to time, as illustrated in FIG. 9B. Thus, the result of integrating
the voltage `Vout-Vin` may be less than or greater than the common
voltage Vcm. That is, a voltage of an input signal supplied to the
ADC circuit 314 is set to be less than or greater than the common
voltage Vcm, and thus, an output of the ADC circuit 314 may be
averaged, thereby removing a low-frequency noise effectively.
[0120] FIG. 9G is a graph showing a variation in an integration
voltage VADC_IN of the integration circuit 313A of FIG. 9B
according to embodiment of the inventive concept. Referring to FIG.
9G, the integration voltage VADC_IN may be output to be less than
or greater than the common voltage Vcm. For example, if the output
voltage Vout is greater than a voltage of the input signal Vin, the
integration voltage VADC_IN may be greater than the common voltage
Vcm, and if the output voltage Vout is less than the voltage of the
input signal Vin, the integration voltage VADC_IN may be less than
the common voltage Vcm. Also, as illustrated in FIG. 9G, the
integration voltage VADC_IN is not influenced by noise, and thus, a
controller (not shown) may easily determine whether a touch screen
panel is touched by setting a threshold appropriately.
[0121] FIG. 10A is a circuit diagram of an integration circuit 313C
that is another embodiment of the integration circuit 313A included
in the touch data generator 310 of FIG. 9B, according to the
inventive concept. Referring to FIG. 10A, the integration circuit
313C uses a reference signal Vref as an input signal instead of the
input signal Vin used in the embodiment of FIG. 9B. The integration
circuit 313C of FIG. 10A is a switched capacitor integration
circuit but it may be embodied as a Gm-C integration circuit.
[0122] FIG. 10B is a waveform diagram of an output voltage Vout and
the reference signal Vref used in the integration circuit 313C of
FIG. 10A, and an input signal Vin, according to an embodiment of
the inventive concept. The reference signal Vref may be embodied as
a square-wave signal or a sinusoidal-wave signal as the input
signal Vin, and an amplitude of the reference signal Vref may be
greater than that of the input signal Vin.
[0123] Referring to FIG. 10B(a), the amplitude of the reference
signal Vref may be set to correspond to an intermediate level of an
inclined section of the output voltage Vout, so that an integration
voltage VADC_IN when touching is not made may approximate nearly a
common voltage Vcm. Also, FIG. 10B(b) reveals if reference signal
Vref is used instead of the input signal Vin, then the integration
voltage VADC_IN when touching is not made approximates more the
common voltage Vcm. Thus, sensing sensitivity may be improved
greatly by increasing the difference of the integration voltages
VADC_IN between when touching is not made and when touching is
made.
[0124] FIG. 11 is a block diagram of a touch controller 400
according to another embodiment of the inventive concept. Referring
to FIG. 11, the touch controller 400 includes elements for
performing operations to generate touch data. For example, the
touch controller 400 includes a voltage reading circuit 410, a
first amplification circuit 420, a first anti-aliasing filter (AAF)
430, an integration circuit 440, and an ADC 450. The touch
controller 400 may further include a second amplification circuit
470 that has the same or similar characteristics as the first
amplification circuit 420, and a second AAF 480 that has the same
or similar characteristics as the first AAF 430. A main signal path
is formed using the first amplification circuit 420 and the first
AAF 430, and a sub signal path is formed using the second
amplification circuit 470 and the second AAF 480.
[0125] When the capacitance of a sensing unit (not shown) changes,
an output voltage corresponding to the change in the capacitance is
generated using the voltage reading circuit 410 and the first
amplification circuit 420. The output voltage output from the first
amplification circuit 420 may pass through the first AAF 430. Touch
data data generated by the ADC 450 may pass through a digital
filter 460 in a subsequent operation. In this case, before passing
through the digital filter 460, the touch data data may pass
through an AAF so that a high-frequency component may be removed
from the touch data data. To this end, the first AAF 430 may be
disposed between the first amplification circuit 420 and the
integration circuit 440.
[0126] A plurality of signals that indicate a change in the
capacitances of a plurality of sensing units (not shown),
respectively, are supplied sequentially to the voltage reading
circuit 410. In order to sense a change in the capacitances of the
plurality of sensing units, a plurality of pulse signals each
having a particular frequency corresponding to one of the plurality
of sensing units are supplied to the voltage reading circuit 410.
The second amplification circuit 470 and the second AAF 480 may be
further included in the touch controller 200 in order to extract
only an actual signal component from an output of the first AAF
430. Also, a pulse signal, e.g., an input signal Vin, the phase of
which is the same as that of a pulse signal supplied to first
amplification circuit 420 is supplied to the second amplification
circuit 470. Although not shown, a voltage of the sensing unit is
applied to one input terminal of an amplifier included in the first
amplification circuit 420, where an amplifier included in the
second amplification circuit 470 may have a structure in which one
input terminal is connected to an output terminal. The difference
between an output of the first AAF 430 and an output of the second
AAF 480 is calculated by a predetermined subtractor, and thus, only
an actual signal component is supplied to the integration circuit
440.
[0127] The frequencies of pulse signals supplied to the elements of
the touch controller 400 of FIG. 11 may be synchronized with a line
scan frequency of a display (not shown) in order to minimize
frequency interferences during a displaying operation. For example,
the input signal Vin supplied to the voltage reading circuit 410
may also be supplied to the first amplification circuit 420, the
second amplification circuit 470 and the integration circuit 440.
Also, a voltage signal, the phase of which is equal or similar to
the phase of the input signal Vin and the amplitude of which is
different from the amplitude of the input signal Vin, may be
supplied to the first amplification circuit 420, the second
amplification circuit 470, and the integration circuit 440.
[0128] FIG. 12A is a block diagram of a general LCD 500A that
includes a plurality of touch controllers T/C according to an
embodiment of the inventive concept. Referring to FIG. 12A, the LCD
500A may include a timing controller 510A that controls the overall
timing for displaying an image and a voltage generator 520A that
generates various voltages for driving the LCD 500A. The LCD 500A
may further include a display panel 550A, at least one gate driver
530A that drives a gate line of the display panel 550A, and at
least one source driver 540A that drives a source line of the
display panel 550A. Each of the touch controllers T/C may receive
timing information from the timing controller 510A. Thus, the touch
controllers T/C may be included in the at least one gate driver
530A or the at least one source driver 540A, respectively. FIG. 12A
illustrates that the touch controllers T/C are included, for
example, in the at least one source driver 540A, respectively. The
timing information transmitted from the timing controller 510A to
the source driver 540A may be supplied simultaneously to the touch
controllers T/C included in the at least one source driver 540A.
The touch controllers T/C sense a capacitance value of a sensing
unit of a touch screen panel (not shown) that may be attached to
the display panel 550A, and generate touch data from the timing
information received from the timing controller 510A.
[0129] FIG. 12B is a block diagram of a general LCD 500B that
includes a touch controller T/C according to an embodiment of the
inventive concept. Referring to FIG. 12B, in the LCD 500B, the
touch controller T/C is included in a timing controller 510B. In
this case, the touch controller T/C may receive timing information
directly in the timing controller 510B. Although not shown, the
touch controller T/C may be electrically connected to a touch
screen panel that may be attached to a display panel 550B, and thus
may sense a change in the capacitance of a sensing unit of the
touch screen panel and generate touch data according to the change
in the capacitance.
[0130] FIG. 13 is a block diagram of an integrated circuit (IC)
600, in which a touch controller 610 and a display driving unit 630
are integrated together, according to an embodiment of the
inventive concept. In FIG. 13, the IC 600 is embodied as a
semiconductor chip that communicates with a host controller 650.
The semiconductor chip 600 includes the touch controller 610 as
described above in the previous embodiments, and the display
driving unit 630 that acts as a display driving circuit. Since the
touch controller 610 and the display driving unit 630 are
integrated together in the same semiconductor chip 600,
manufacturing costs may be saved. Also, a sensing signal output
from the touch controller 610 and a signal output from the display
driving unit 630 may be synchronized with each other, thereby
reducing influences caused by noise generated during a touch screen
operation.
[0131] The touch controller 610 may be constructed in various ways
in order to perform the touch screen operation. For example, the
touch controller 610 may include a readout circuit 611 that
generates touch data, a parasitic capacitance compensation circuit
612 that reduces a parasitic capacitance component in a sensing
unit, an ADC 613 that converts analog data into a digital signal, a
supply voltage generator 614 that generates a supply voltage, a
memory unit 615, an MCU 616, a digital FIR LPF 617, an oscillator
618 that generates a low-power oscillation signal, an interface
unit 619 that exchanges a signal with the host controller 650, and
a control logic unit 620. The display driving unit 630 may include
a source driver 631 that generates gray-scale data for a displaying
operation, a gray-scale voltage generator 632, a display memory 633
that stores display data, a timing control logic unit 634, and a
power generator 635 that generates at least one supply voltage. The
display driving unit 630 may further include a central processing
(CPU) and RGB interface unit 636 that controls the overall
operations of the display driving unit 630 or performs an interface
with the host controller 650.
[0132] The touch controller 610 may receive at least one piece of
timing information Timing info from the display driving unit 630.
For example, the control logic unit 620 of the touch controller 610
receives various timing information VSYCN, HSYCN, and Dotclk to be
synchronized with a display output signal from the timing control
logic unit 634 of the display driving unit 630. The control logic
unit 620 may generate a control signal for controlling a timing of
generating the touch data, from the at least one piece of timing
information Timing info.
[0133] The display driving unit 630 may also receive at least one
piece of information from the touch controller 610. Referring to
FIG. 13, the display driving unit 630 may receive a status signal,
e.g., a sleep status signal, from the touch controller 610. The
display driving unit 630 receives the sleep status signal from the
touch controller 610 and performs an operation corresponding to the
sleep status signal. If the touch controller 610 enters a sleep
mode, it means that touching has not been made for a predetermined
time. In this case, the display driving unit 630 may discontinue
supplying the timing information Timing info to the touch
controller 610. Therefore, it is possible to save power consumption
in a device, e.g., a mobile device, in which the semiconductor chip
600 is installed.
[0134] Also, as illustrated in FIG. 13, each of the touch
controller 610 and the display driving unit 630 includes a circuit
block that generates power, a memory that stores predetermined
data, and a control unit that controls the operations of the
remaining blocks. Thus, if the touch controller 610 and the display
driving unit 630 are integrated together in the same semiconductor
chip, then the memory, the circuit block, and the control unit may
be embodied to be used commonly by the touch controller 610 and the
display driving unit 330.
[0135] FIGS. 14A and 14B illustrate an interrelation between a
touch controller and a display driving unit as illustrated in FIG.
13. Referring to FIG. 14A, a semiconductor chip 600 that drives a
display device (not shown) may include the touch controller
(including the memory, AFE, MCU and control logic as shown for
example) and the display driving unit (including the power
generator, output driver, control logic and display memory as shown
for example), and the touch controller and the display driving unit
may exchange at least one piece of information, e.g., timing
information and status information, with each other. Also, each of
the touch controller and the display driving unit may supply a
supply voltage to the other or may receive the supply voltage from
the other. FIG. 14A schematically illustrates the touch controller
and the display driving unit for convenience of explanation, in
which an analog front end (AFE) included in the touch controller
may include a voltage reading circuit, an amplification circuit, an
integration circuit, and an ADC. A case where the touch controller
provides sleep status information to the display driving unit and
the display driving unit applies the supply voltage to the touch
controller according to an embodiment of the inventive concept,
will now be described.
[0136] As illustrated in FIG. 14B, if a display is turned off and a
touch input is deactivated, i.e., if both the touch controller and
the display enter a sleep mode, then the display driving unit
prevents a supply voltage or timing information from being supplied
to the touch controller. In this case, only a register included in
the display driving unit may be activated, thereby minimizing power
consumption.
[0137] If the touch input is deactivated and the display is
activated, i.e., if the touch controller enters the sleep mode and
the display enters a normal mode, then the display driving unit
generates the supply voltage to be used therein but the supply
voltage is not applied to the touch controller since the touch
controller does not consume power. Also, the display driving unit
does not provide the timing information to the touch
controller.
[0138] If the touch input is activated and the display is
deactivated, i.e., if the touch controller enters the normal node
and the display enters the sleep mode, then it is periodically
checked whether touching is made since the touch input is
activated. In this case, the display driving unit is kept
deactivated while operating in a low-power consumption mode.
However, in order to check whether touching is made, the display
driving unit generates the timing information and the supply
voltage to be applied to the touch controller and supply them to
the touch controller.
[0139] In general, when both the touch input and the display are
activated, i.e., if both the touch controller and the display enter
the normal mode, then the display driving unit generates the timing
information and the supply voltage and applies them to the touch
controller.
[0140] It is concluded from the above four cases that the supply
voltage generator of the display driving unit may generate a supply
voltage when at least one of the touch controller and the display
driving unit is activated. Also, a control logic unit of the
display driving unit may generate the timing information and supply
it to the touch controller only when the touch controller
operates.
[0141] FIGS. 15A to 15C illustrate embodiments of a printed circuit
board (PCB) structure of a display device 700 that includes a touch
panel 720, according to the inventive concept. Here, the touch
panel 720 and a display panel 740 are disposed apart from each
other.
[0142] Referring to FIG. 15A, the display device 700 may include a
window glass 710, the touch panel 720, and the display panel 740. A
polarizing plate 730 may be disposed between the touch panel 720
and the display panel 740 for an optical characteristic.
[0143] In general, the window glass 710 is formed of acryl or
tempered glass and protects a module from external impacts or
scratches caused by repeated touches. The touch panel 720 is formed
by patterning transparent electrodes, for example, indium tin oxide
(ITO) electrodes, on a glass substrate or a polyethylene
terephthlate (PET) film. A touch screen controller 721 may be
mounted on a flexible printed circuit board (FPCB) in the form of a
chip on board (COB), and senses a change in the capacitance of each
of the electrodes, extracts the coordinates of a touching point,
and provides the coordinates of the touching point to a host
controller (not shown). In general, the display panel 740 is
manufactured by putting two pieces of glass, i.e., an upper glass
plate and a lower glass plate, together. Also, in general, the
display driving circuit 741 is attached to a mobile display panel
in the form of a chip on glass (COG).
[0144] FIG. 15B illustrates another embodiment of the PCB structure
of the display device 700 that includes a touch panel 720,
according to the inventive concept. Referring to FIG. 15B, a touch
controller 721 may be disposed on a main board 760 and a voltage
signal transmitted from a sensing unit (not shown) may be exchanged
between the touch panel 720 and the touch controller 721 via an
FPCB. A display driving circuit 741 may be mounted on a display
panel 740 in the form of a COG as illustrated in FIG. 15A. The
display driving circuit 741 may be electrically connected to the
main board 760 via the FPCB. That is, the touch controller 721 and
the display driving circuit 741 may exchange various information
and signals with each other via the main board 760.
[0145] FIG. 15C illustrates another embodiment of the PCB structure
of the display device 700, in which a touch controller and a
display driving unit are integrated together in the same
semiconductor chip 751, according to the inventive concept.
Referring to FIG. 15C, the display device 700 may include a window
glass 710, a touch panel 720, a polarizing plate 730, and a display
panel 740. In particular, the semiconductor chip 751 may be mounted
on a display panel 740 in the form of COG. The touch panel 720 and
the semiconductor chip 751 may be electrically connected to each
other via an FPCB.
[0146] FIG. 15D illustrates the panel structure of the display
device 700 illustrated in FIG. 15A, 15B, or 15C, according to an
embodiment of the inventive concept. FIG. 15D illustrates an
organic light-emitting diode (OLED) as the display device 700.
Referring to FIG. 15D, a sensing unit may be formed by patterning a
transparent electrode, e.g., an ITO (sensor) and may be formed on a
glass plate separated apart from a display panel. The glass plate
on which the sensing unit is disposed may be separated apart from a
window glass via a predetermined air gap or resin, and may be
separated apart from an upper glass plate and a lower glass plate
that constitute the display panel via a polarizing plate.
[0147] FIGS. 16A to 16C illustrate embodiments of a PCB structure
of a display device 800, in which a touch panel and a display panel
are united together, according to the inventive concept. Referring
to FIG. 16A, the display device 800 may include a window glass 810,
a display panel 820, and a polarizing plate 830. In particular, the
touch panel may be fabricated by patterning transparent electrodes
on an upper glass plate of the display panel 820 rather than on an
additional glass plate. FIG. 16A illustrates that a plurality of
sensing units SU are arranged on the upper glass plate of the
display panel 820. Although not shown, when a panel structure is
fabricated as described above, a touch controller and a display
driving circuit may be integrated together in the same
semiconductor chip 821.
[0148] If the touch controller and the display driving circuit may
be integrated together in the same semiconductor chip 821, then a
voltage signal T_sig and image data I_data are supplied to the
semiconductor chip 821 from each of the sensing units SU and an
external host, respectively. Also, the semiconductor chip 821
processes the image data I_data, generates gray-scale data (not
shown) for actually driving the display device 800, and supplies
the gray-scale data to the display panel 820. To this end, the
semiconductor chip 821 may include pads related to touch data and
pads related to the image data I_data and the gray-scale data. The
semiconductor chip 821 receives the voltage signal T_sig from each
of the sensing units SU via a conductive line connected to one side
of the touch panel. When the pads are arranged on the semiconductor
chip 821, the pad for receiving the voltage signal T_sig may be
located adjacent to the conductive line for delivering the voltage
signal T_sig in order to reduce noise in data. Although not shown
in FIG. 16A, if the conductive line for supplying the gray-scale
data to the display panel 820 is disposed to be opposite to a
conductive line for supplying a touch data voltage signal T_sig,
then the pad for providing the gray-scale data may also be located
to be opposite to pads for receiving the voltage signal T_sig.
[0149] The display device 800 of FIG. 16B has a construction
similar to that of the display device of FIG. 16A. Referring to
FIG. 16B, a voltage signal transmitted from a sensing unit is
supplied directly to a semiconductor chip 821 via a conductive line
rather than via an FPCB.
[0150] The display device 800 of FIG. 16C also has a construction
similar to that of the display device of FIG. 16A. However,
referring to FIG. 16C, in the display device 800, a signal path in
which a voltage signal transmitted from a sensing unit to a
semiconductor chip 821 is different from in the display device of
FIG. 16A. In the current embodiment, a pad for receiving the
voltage signal from the sensing unit is disposed closest to a
conductive line from among a plurality of pads arranged on the
semiconductor chip 821.
[0151] FIG. 16D illustrates the panel structure of the display
device 800 illustrated in FIG. 16A, 16B, or 16C, according to
another embodiment of the inventive concept. In a display device
according to an embodiment of the inventive concept, a touch panel
and a display panel may be effectively united together. Referring
to FIG. 16D, an OLED is embodied as the display device 800. In the
current embodiment, a sensing unit is fabricated by forming a
transparent electrode, e.g., an ITO (sensor), directly on an upper
glass plate of the display panel, rather than on an additional
glass plate or on a PET film. In this case, a touch display panel
may be fabricated while reducing manufacturing costs and module
thickness, but the distance between the transparent electrode and a
top glass of the display device 800 becomes small, thereby
increasing a vertical parasitic capacitance component in the
sensing unit. However, according to the above embodiments, it is
possible to reduce influences, caused by the whole parasitic
capacitance components including a vertical parasitic capacitance
component generated in a sensing unit. Accordingly, as described
above, the touch panel and the display panel may be united together
effectively.
[0152] FIGS. 17A and 17B illustrate the structure of a
semiconductor chip that includes a touch controller and a display
driving circuit unit, and the structure of an FPCB according to
embodiments of the inventive concept. The semiconductor chip
includes pads for transmitting and receiving signals related to the
touch controller and pads for transmitting and receiving signals
related to the display driving circuit unit. The pads may be
electrically connected to a touch panel, a display panel, and a
host controller via connection terminals of the FPCB. When the
semiconductor chip is fabricated, a region in which the touch
controller is located may be separated apart from a region in which
the display driving circuit unit is located. When the connection
terminals are arranged in the FPCB, connection terminals connected
to the signals related to the touch controller and connection
terminals connected to the signals related to the display driving
circuit unit may be disposed to correspond to the pads of the
semiconductor chip.
[0153] FIGS. 18A and 18B illustrate embodiments of a display device
having a semiconductor chip in which a touch controller and a
display driving circuit are included, according to the inventive
concept. Specifically, FIG. 18A illustrates that the semiconductor
chip is disposed on a glass plate of a display panel in the form of
COG, and FIG. 18B illustrates that the semiconductor chip is
disposed on a film of a display panel in the form of chip on film
(COF). In general, when the touch controller and the display
driving circuit are disposed on different chips, the touch
controller may be disposed in the form of COF and the display
driving circuit may be disposed in the form of COG, but in another
embodiment according to the inventive concept, the semiconductor
chip that includes the touch controller and the display driving
circuit may have a COG or COF structure.
[0154] While the inventive concept has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood that various changes in form and details may be made
therein without departing from the spirit and scope of the
following claims.
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