KR20130053060A - Liquid crystal display device having touch sensor and method for driving the same - Google Patents

Liquid crystal display device having touch sensor and method for driving the same Download PDF

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Publication number
KR20130053060A
KR20130053060A KR1020110118547A KR20110118547A KR20130053060A KR 20130053060 A KR20130053060 A KR 20130053060A KR 1020110118547 A KR1020110118547 A KR 1020110118547A KR 20110118547 A KR20110118547 A KR 20110118547A KR 20130053060 A KR20130053060 A KR 20130053060A
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South Korea
Prior art keywords
common voltage
liquid crystal
touch sensor
crystal panel
touch
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KR1020110118547A
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Korean (ko)
Inventor
한성수
김성철
김훈배
김상규
권수진
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엘지디스플레이 주식회사
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Priority to KR1020110118547A priority Critical patent/KR20130053060A/en
Publication of KR20130053060A publication Critical patent/KR20130053060A/en

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412—Digitisers structurally integrated in a display
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2203/00—Indexing scheme relating to G06F3/00 - G06F3/048
    • G06F2203/041—Indexing scheme relating to G06F3/041 - G06F3/045
    • G06F2203/04103—Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Human Computer Interaction (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Computer Hardware Design (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Position Input By Displaying (AREA)

Abstract

PURPOSE: A liquid crystal display device including a touch sensor and a driving method thereof are provided to improve touch sensitivity and a touch recognition rate by offsetting noises. CONSTITUTION: A touch sensor(20) is attached to or embedded in a liquid crystal panel. A readout circuit(30) drives the touch sensor and detects touch row data by using a readout signal received from the touch sensor. An inversion amplifier inverts a feedback common voltage from the liquid crystal panel and outputs the inverted voltage. A noise offsetting unit(32) removes noise elements from a common voltage of the readout signal by offsetting the noise elements from the common voltage included in the readout signal of the touch sensor by the inverted feedback common voltage. [Reference numerals] (12) Data driver; (14) Gate driver; (18) Timing controller; (30) Readout IC; (32) Noise offsetting unit; (40) Common voltage generating unit

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display device having a touch sensor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a touch sensor, and more particularly, to a liquid crystal display device having a touch sensor capable of improving touch sensitivity and touch recognition rate by canceling noise from the display device, and a driving method thereof.

2. Description of the Related Art Today, a touch sensor capable of inputting information by touching on a screen of various display devices is widely applied as an information input device of a computer system. The touch sensor allows the user to easily use the display information by simply touching the screen with a finger or a stylus to select or move the display information.

The touch sensor senses a touch and a touch position generated on the screen of the display device and outputs the touch information, and the computer system analyzes the touch information and executes an instruction. As a display device, a flat panel display device such as a liquid crystal display device, a plasma display panel, and an organic light emitting diode display device is mainly used. As the touch sensor technology, there are resistance film type, capacitive type, optical type, infrared type, ultrasonic type, and electromagnetic type depending on the sensing principle.

The touch sensor may be constituted by an on-cell touch sensor manufactured in the form of a panel and attached to the upper part of the display device, or an in-cell touch sensor built in a pixel matrix of the display device ). As the touch sensor, a photo touch sensor that recognizes a touch according to light intensity using a photo transistor and a capacitive touch sensor that recognizes a touch according to a capacitive variable are mainly used.

In a display device having a touch sensor, a noise component generated from the display device is added to a received signal of the touch sensor, thereby lowering a signal-to-noise ratio (SNR), thereby lowering a sensing sensitivity or delaying a detection time of the sensing signal.

In particular, in a liquid crystal display, whenever a positive data signal and a negative data signal are supplied to a data line, a ripple component in which the common voltage signal is shaken toward the positive or negative polarity along the data signal is generated. The ripple component of the common voltage signal affects the touch sensor as a noise component due to parasitic capacitance between the touch sensor and the liquid crystal display. When the noise component of the display device is larger than the variable capacitance of the touch point, it is difficult to sense the touch point, which causes a problem in that the touch sensor malfunctions.

The present invention has been made to solve the above-described problems of the prior art, the problem to be solved by the present invention is a liquid crystal display device having a touch sensor that can improve the touch sensitivity and touch recognition rate by canceling the noise of the display device and its It is to provide a driving method.

In order to solve the above problems, a liquid crystal display device having a touch sensor according to an embodiment of the present invention includes a liquid crystal panel; A touch sensor attached to or embedded in the liquid crystal panel and integrated; A readout circuit for driving the touch sensor and detecting touch low data using a readout signal received from the touch sensor; An inverting amplifier inverting and outputting a common voltage fed back from the liquid crystal panel; The noise component of the common voltage is removed from the readout signal by canceling the inverted feedback common voltage from the inverting amplifier and the noise component of the common voltage flowing from the liquid crystal panel and included in the readout signal of the touch sensor. And a noise attenuation section.

The inverting amplifier is embedded in the common voltage generator for generating and supplying the common voltage to the liquid crystal panel.

The noise attenuator includes a first line for supplying the readout signal, a second line for supplying the inverted feedback common voltage, and a capacitor formed between the first and second lines. Has

The noise attenuation part is formed in the touch sensor or in an FPC connected between the touch sensor and the touch driving board on which the readout circuit is mounted.

The noise reduction part is formed in the FPC by forming a plurality of the first lines and a plurality of the second lines in the FPC alternately to form the capacitor between adjacent first and second lines.

The touch driving board is further formed with a common line for commonly supplying the inverted feedback common voltage to a plurality of second lines formed in the FPC.

The inverting amplifier is formed on the touch driving board or embedded in the readout circuit and receives a common voltage fed back from the liquid crystal panel through a display driving board driving the liquid crystal panel.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display device having a touch sensor, the method comprising: driving a liquid crystal panel and inverting and amplifying a common voltage fed back from the liquid crystal panel to supply an inverted feedback common voltage; Driving a touch sensor attached to or embedded in the liquid crystal panel and supplying a readout signal received from the touch sensor; Canceling the inverted feedback common voltage and the noise component of the common voltage flowing from the liquid crystal panel and included in the readout signal of the touch sensor to remove the noise component of the common voltage from the readout signal; And detecting touch row data using the readout signal from which the noise component is removed.

The inverted feedback common voltage is supplied from a common voltage generator which generates and supplies a common voltage to the liquid crystal panel.

The noise component of the common voltage is canceled by coupling of a capacitor formed between the first line supplying the readout signal and the second line supplying the inverted feedback common voltage.

A liquid crystal display device having a touch sensor and a driving method thereof according to the present invention are characterized in that the noise attenuator cancels the noise component of the liquid crystal panel included in the readout signal of the touch sensor by coupling with an inverted feedback common voltage. Noise component of the included liquid crystal panel can be effectively removed. Accordingly, the present invention can improve the touch sensing sensitivity by detecting the touch low data using a readout signal in which the noise component of the display device is sufficiently reduced.

1 is a block diagram schematically illustrating a display device having a touch sensor according to an exemplary embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of the touch sensor illustrated in FIG. 1.
FIG. 3 is an input / output waveform diagram of the noise reduction unit shown in FIG. 1.
4 is a circuit diagram schematically illustrating a touch sensor driving device according to an exemplary embodiment of the present invention.
5 is a diagram schematically illustrating a module configuration of a display device having a touch sensor according to an exemplary embodiment of the present invention.
FIG. 6 is a diagram illustrating in detail the noise reduction unit formed in the FPC illustrated in FIG. 5.
FIG. 7 is a waveform diagram illustrating a noise reduction principle of the noise reduction unit illustrated in FIG. 6.

1 is a block diagram schematically illustrating a liquid crystal display device having a touch sensor according to an exemplary embodiment of the present invention, and FIG. 2 is a diagram illustrating a structure of the touch sensor 20 illustrated in FIG. 1.

A liquid crystal display device having a touch sensor shown in FIG. 1 includes a panel driver including a data driver 12 and a gate driver 14 for driving the liquid crystal panel 10, a timing controller 18 for controlling the panel driver, A common voltage generator 40 which supplies a common voltage Vcom to the liquid crystal panel 10, inverts and amplifies the common voltage fed back from the liquid crystal panel 10, and outputs the inverted feedback common voltage / Vcom; The inverted feedback common voltage input from the common voltage generator 40 and the readout IC 30 driving the touch sensor 20 and detecting and outputting touch low data from the readout signal of the touch sensor 20. / Vcom) to reduce the noise of the liquid crystal panel 10 from the readout signal of the touch sensor 20 and to output the noise reduction unit 32 to the readout IC 30.

The liquid crystal panel 10 includes a color filter substrate on which a color filter array is formed, a thin film transistor substrate on which a thin film transistor array is formed, a liquid crystal layer between the color filter substrate and a thin film transistor substrate, and an outer surface of the color filter substrate and the thin film transistor substrate. It has a polarizing plate attached to each. The liquid crystal panel 10 displays an image through a pixel matrix in which a plurality of pixels are arranged. Each pixel implements a desired color by a combination of red, green, and blue sub-pixels that adjust the light transmittance by varying the liquid crystal array according to the data signal. Each sub pixel includes a thin film transistor TFT connected to the gate line GL and the data line DL, a liquid crystal capacitor Clc connected in parallel with the thin film transistor TFT, and a storage capacitor Cst. The liquid crystal capacitor Clc charges the difference voltage between the data signal supplied to the pixel electrode through the thin film transistor TFT and the common voltage Vcom supplied to the common electrode, drives the liquid crystal according to the charged voltage, . The storage capacitor Cst stably maintains the voltage charged in the liquid crystal capacitor Clc.

The timing controller 18 processes image data input from an external host computer and supplies the same to the data driver 12. For example, the timing controller 18 corrects and outputs data by overdriving driving to add an overshoot value or an undershoot value according to the data difference between adjacent frames in order to improve the response speed of the liquid crystal. can do. In addition, the timing controller 18 drives the data driver 12 using a plurality of synchronization signals input from a host computer, that is, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal, and a dot clock. A data control signal for controlling timing and a gate control signal for controlling the driving timing of the gate driver 14 are generated, and the data control signal and the gate control signal are output to the data driver 12 and the gate driver 14, respectively. The data control signal includes a source start pulse and a source sampling clock for controlling the latch of the data signal, a polarity control signal for controlling the polarity of the data signal, and a source output enable signal for controlling the output period of the data signal. The gate control signal includes a gate start pulse and gate shift clock for controlling the scanning of the gate signal, a gate output enable signal for controlling the output period of the gate signal, and the like.

The gate driver 14 sequentially drives a plurality of gate lines GL formed in the thin film transistor array of the liquid crystal panel 10 in response to a gate control signal from the timing controller 18. The gate driver 14 supplies a scan pulse of a gate-on voltage for each scan period of each gate line GL, and supplies a gate-off voltage in the remaining periods in which another gate line GL is driven. Here, the scan pulse width supplied with the gate on voltage is controlled by the gate output enable signal from the timing controller 18.

The data driver 12 supplies a data signal to a plurality of data lines DL formed in the thin film transistor array of the liquid crystal panel 10 in response to a data control signal from the timing controller 18. The data driver 12 converts input digital data into positive / negative analog data signals using a gamma voltage, and supplies the data signals to the data lines DL each time the gate lines GL are driven.

The common voltage generator 40 generates a common voltage Vcom and supplies it to the liquid crystal panel 10. At this time, the common voltage generator 40 inverts the common voltage fed back from the liquid crystal panel 10 by using an inverting amplifier, and compensates the common voltage Vcom with the inverted feedback common voltage / Vcom to compensate for the liquid crystal panel ( 10). At the same time, the common voltage generator 40 outputs the inverted feedback common voltage / Vcom to the noise attenuator 32 connected between the touch sensor 20 and the touch controller 30. The common voltage fed back from the liquid crystal panel 10 includes a ripple component that swings toward the positive or negative polarity along the data signal as shown in FIG. 3, that is, the noise component of the liquid crystal panel 10. The common voltage generator 40 inverts the fed back common voltage including the noise component and supplies the inverted common voltage to the noise canceling unit 32 as shown in FIG. 3.

The touch sensor 20 mainly uses a capacitive touch sensor that senses a touch by detecting a change in capacitance generated when a small amount of electric charge moves to a touch point when a human body or a conductor such as a stylus touches the touch point. The touch sensor 20 may be attached on the liquid crystal panel 10 or embedded in the pixel array of the liquid crystal panel 10.

For example, in the capacitive touch sensor 20 attached to the liquid crystal panel 10, a plurality of first sensing electrodes 22 arranged in a row direction as shown in FIG. 2 are electrically connected to each other. The transmission lines TX1 to TXn and the plurality of second sensing electrodes 24 arranged in the column direction may be electrically connected to each other and may include a plurality of reception (readout) lines RX1 to RXm. Each of the first and second sensing electrodes 22 and 24 is mainly formed in a rhombus shape and may be formed in various other shapes. The first and second sensing electrodes 22 and 24 are driven by the readout IC 30 to form capacitance by a fringe field, and a capacitor with a conductive touch object that touches the touch sensor 20. Form a to output a signal indicating whether or not the touch by changing the capacitance. Each of the transmission lines TX1 to TXn of the touch sensor 20 is sequentially driven by a scan waveform supplied from the readout IC 30, and a readout signal indicating whether a touch is received through the reception lines RX1 to RXm is read. It is supplied to the out IC 30.

The noise attenuator 32 couples the readout signal output from the touch sensor 20 and the inverted feedback common voltage / Vcom supplied from the common voltage generator 40 by using a capacitor to form a touch sensor. The noise component of the liquid crystal panel 10 included in the readout signal of 20 is attenuated. The noise component of the common voltage Vcom generated in the liquid crystal panel 10 is introduced into the touch sensor 20 through the parasitic capacitor and included in the readout signal of the touch sensor 20 as shown in FIG. 3. The noise attenuator 32 converts the noise component of the common voltage Vcom included in the readout signal of the touch sensor 20 into the inverted feedback common voltage / Vcom and the capacitor from the common voltage generator 40. To offset. Accordingly, the noise attenuator 32 supplies the readout signal of the touch sensor 20 in which the noise component of the liquid crystal panel 10 is attenuated to the readout IC 30 as shown in FIG. 3. The noise attenuator 32 includes a capacitor formed between the reception lines RX1 to RXm of the touch sensor 20 and the supply line of the inverted feedback common voltage / Vcom. The noise attenuator 32 may be formed in the touch sensor 20 by forming a plurality of / Vcom supply lines to form capacitors and the reception lines RX1 to RXm in the touch sensor 20. In addition, the noise attenuator 32 forms a plurality of / Vcom supply lines to form each of the lead-out lines and the capacitor in a flexible printed circuit (FPC) that electrically connects the touch sensor 20 and the read-out IC 30. By forming in the FPC.

The readout IC 30 supplies a driving signal to the touch sensor 20 and detects touch raw data from a readout signal input from the touch sensor 20 via the noise attenuator 32 to detect the microcontrol unit. It is supplied to a signal processor (not shown) such as a micro control unit (MCU).

The transmitter of the readout IC 30 drives the touch sensor 20 by sequentially supplying scan pulses to the transmission lines TX1 to TXn of the touch sensor 20.

The receiving unit of the readout IC 30 receives the touch low from the readout signal input via the noise attenuation unit 32 from the readout signal of the touch sensor 20 inputted by the noise attenuation unit 32. Data is detected and output. The receiver of the readout IC 30 uses an amplifier to compare the readout signal from the noise attenuation unit 32 with a preset reference voltage, amplify the readout signal equal to or greater than the reference voltage, and indicate whether the touch is low. Output as (Raw) signal. The receiver of the readout IC 30 converts an analog touch low signal into digital touch low data by using an analog-to-digital converter (ADC).

The signal processor (not shown) controls the transmitter and the receiver of the readout IC 30, calculates touch coordinate values (XY coordinate values) using the touch row data supplied from the readout IC 30, and sends them to the host computer. Supply. The signal processor calculates the touch coordinate value (XY coordinate) based on the position information (X coordinate) of the reception line RX to which the touch row data is output and the position information (Y coordinate) of the scanned transmission line TX. .

As described above, in the liquid crystal display having the touch sensor according to the present invention, the noise attenuator 32 includes the noise component of the liquid crystal panel 10 included in the readout signal of the touch sensor 20. The noise component of the liquid crystal panel 10 included in the readout signal of the touch sensor 20 may be effectively removed by canceling the coupling with the inverted feedback common voltage (/ Vcom). Accordingly, the present invention can improve the touch sensing sensitivity by detecting the touch low data using a readout signal in which the noise component of the display device is sufficiently reduced.

4 is a circuit diagram schematically illustrating a touch sensor driving device according to an exemplary embodiment of the present invention.

The touch sensor driving device illustrated in FIG. 4 includes a touch sensor 20 that forms a mutual capacitor between the transmission line TX and the reception line RX, and a transmission line TX of the touch sensor 20. The transmission unit 31 of the readout IC 30 for supplying a drive signal and the readout signal from the reception line RX of the touch sensor 20 receive the readout signal of the readout IC 30. The common voltage generator 40 supplies an inverted feedback common voltage (/ Vcom) by inverting and amplifying the common voltage fed back from the receiver 33 and the liquid crystal panel 10 (FIG. 1) using the inverting amplifier 42. And the noise component of the liquid crystal panel 10 included in the readout signal by forming the reception line RX of the touch sensor 20, the / Vcom supply line from the common voltage generator 40, and the capacitor C. And a noise attenuation portion 32 for reducing.

The noise component of the common voltage Vcom generated in the liquid crystal panel 10 is introduced into the touch sensor 20 through the parasitic capacitor Cp between the liquid crystal panel 10 and the touch sensor 20 and included in the readout signal. do. The noise attenuator 32 converts the noise component of the common voltage Vcom included in the readout signal of the touch sensor 20 into the inverted feedback common voltage / Vcom and the capacitor (from the common voltage generator 40). Offset by coupling with C).

The inverting amplifier 42 which inverts and amplifies the fed back common voltage and supplies it to the noise attenuator 32 is embedded in the readout IC 30 separately from the common voltage generator 40, or the readout IC 30R is provided. It may be installed on the touch driving board to be mounted.

FIG. 6 is a diagram schematically illustrating a configuration of a liquid crystal display device having a touch sensor according to an exemplary embodiment of the present invention, and FIG. 7 illustrates the noise attenuator 32 of the FPC 60 illustrated in FIG. 6 by way of example. Drawing.

The liquid crystal display device having the touch sensor shown in FIG. 6 includes a liquid crystal panel 10 having a touch sensor 20, a touch drive board 36 on which the readout IC 30 is mounted, a touch sensor 20, and A display driver board 72 having an FPC 60 electrically connected between the touch drive board 36 and a noise attenuator 32 formed thereon and a common voltage generator 74 mounted thereon, a liquid crystal panel 10 and a display. An FPC 70 electrically connected between the drive boards 72 and an FPC 40 electrically connected between the display drive board 72 and the touch drive board 36 are provided.

The common voltage generator 40 and the like are formed on the display driving board 72, and are electrically connected to the liquid crystal panel 10 through the FPC 70. The common voltage generator 40 inverts the common voltage Vcom fed back from the liquid crystal panel 10 via the FPC 70 to convert the inverted feedback common voltage / Vcom through the FPC 74 through the touch driving board. Supply to 36.

A readout IC 30 or the like is formed on the touch driving board 36, and supplies the inverted feedback common voltage / Vcom from the common voltage generator 40 to the FPC 60.

The FPC 60 electrically connects the transmission lines TX1 to TXn (FIG. 2) of the touch sensor 20 and the readout IC 30 on the touch drive board 36, and receives the touch sensor 20. The lines RX1 to RXm (FIG. 2) are electrically connected to the readout IC 30.

In particular, the FPC 60 includes a plurality of lead-out lines 62, a plurality of lead-out lines 62, and an insulating layer that are individually connected to the reception lines RX1 to RXm of the touch sensor 20 as shown in FIG. 6. And a noise attenuation portion 32 composed of a plurality of / Vcom supply lines 64 which are formed side by side or overlapping with each other to form a line capacitor C. In other words, each of the plurality of lead-out lines 62 and the plurality of / Vcom supply lines 64 are alternately formed on the FPC 60 between the adjacent lead-out line 62 and the / Vcom supply line 64. The line capacitor C is formed. The plurality of / Vcom supply lines 64 formed on the FPC 60 are commonly connected to the common line 66 formed on the touch drive board 36 to supply the inverted feedback common voltage / Vcom. The noise attenuator 32 uses the line capacitor C to reduce the noise component of the common voltage Vcom included in the readout signal of the touch sensor 20 and the inverted feedback common voltage (/ Vcom) as shown in FIG. 7. Noise components cancel each other out. Accordingly, the noise canceling unit 32 supplies the readout signal in which the noise component of the liquid crystal panel 10 is attenuated to the readout IC 30. Accordingly, the sensing sensitivity may be improved by increasing the signal-to-noise ratio (SNR) due to the reduction of the noise component in the readout IC 30.

Meanwhile, in the present invention, only the case where the touch sensor 20 is a capacitive type has been described as an example, but other various touch sensors such as an optical touch sensor may also be applied.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

10: liquid crystal panel 12: data driver
14: gate driver 16: panel driver
18: timing controller 20: touch sensor
22: first sensing electrode 24: second sensing electrode
30: readout IC 31: transmitter
32: noise attenuator 33: receiver
36: touch driving board 40: common voltage generator
42: inverting amplifier 60, 70, 74: FPC
62: Lead out line 64: / Vcom supply line
66: common line 72: display drive board

Claims (10)

A liquid crystal panel;
A touch sensor attached to or embedded in the liquid crystal panel and integrated;
A readout circuit for driving the touch sensor and detecting touch low data using a readout signal received from the touch sensor;
An inverting amplifier inverting and outputting a common voltage fed back from the liquid crystal panel;
The noise component of the common voltage is removed from the readout signal by canceling the inverted feedback common voltage from the inverting amplifier and the noise component of the common voltage flowing from the liquid crystal panel and included in the readout signal of the touch sensor. A liquid crystal display device having a touch sensor, characterized by comprising a noise canceling unit. The method according to claim 1,
And the inverting amplifier is built in a common voltage generator configured to generate and supply the common voltage to the liquid crystal panel. The method according to claim 1,
The noise attenuation unit
A first line supplying the readout signal;
A second line supplying the inverted feedback common voltage;
And a capacitor formed between the first and second lines. The method according to claim 3,
The noise attenuation unit
And a touch sensor formed in the touch sensor, or in an FPC connected between the touch sensor and a touch drive board on which the readout circuit is mounted. The method according to claim 3,
The noise attenuation unit
And a plurality of the first lines and a plurality of the second lines are alternately formed in the FPC to form the capacitor between adjacent first and second lines, thereby forming the touch sensor. Liquid crystal display. The method according to claim 5,
And a common line on the touch driving board to further supply the inverted feedback common voltage to a plurality of second lines formed in the FPC. The method of claim 6,
The inverting amplifier may be formed on the touch driving board or embedded in the readout circuit, and receive a common voltage fed back from the liquid crystal panel through a display driving board driving the liquid crystal panel. Having a liquid crystal display device. Driving the liquid crystal panel and inverting and amplifying the common voltage fed back from the liquid crystal panel to supply an inverted feedback common voltage;
Driving a touch sensor attached to or embedded in the liquid crystal panel and supplying a readout signal received from the touch sensor;
Canceling the inverted feedback common voltage and the noise component of the common voltage flowing from the liquid crystal panel and included in the readout signal of the touch sensor to remove the noise component of the common voltage from the readout signal;
And detecting touch row data by using the readout signal from which the noise component has been removed. The method according to claim 8,
The inverted feedback common voltage is supplied from a common voltage generator for generating and supplying a common voltage to the liquid crystal panel. The method according to claim 8,
The noise component of the common voltage is canceled by coupling of a capacitor formed between the first line supplying the readout signal and the second line supplying the inverted feedback common voltage. Driving method of liquid crystal display device.
KR1020110118547A 2011-11-14 2011-11-14 Liquid crystal display device having touch sensor and method for driving the same KR20130053060A (en)

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KR101450271B1 (en) * 2013-09-10 2014-10-22 국립대학법인 울산과학기술대학교 산학협력단 Apparatus of parallel read out of touch screen
KR20150074257A (en) * 2013-12-23 2015-07-02 엘지디스플레이 주식회사 Touch display device and method for driving the same
US9478167B2 (en) 2013-11-14 2016-10-25 Samsung Display Co., Ltd. Organic light emitting display and method for driving the same
US9600130B2 (en) 2015-01-15 2017-03-21 Samsung Display Co., Ltd. Liquid crystal display device and method of driving the same
US9665220B2 (en) 2014-02-03 2017-05-30 Samsung Display Co., Ltd. Display apparatus and method for driving the same with increased touch recognition
CN109582168A (en) * 2017-09-29 2019-04-05 三星显示有限公司 Show equipment
CN111819528A (en) * 2019-12-26 2020-10-23 深圳市汇顶科技股份有限公司 Capacitance detection circuit, touch chip and electronic equipment
US11995265B2 (en) 2021-12-10 2024-05-28 Samsung Display Co., Ltd. Display device having a sensing controller for controlling the driving of an input sensing layer

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101450271B1 (en) * 2013-09-10 2014-10-22 국립대학법인 울산과학기술대학교 산학협력단 Apparatus of parallel read out of touch screen
US9478167B2 (en) 2013-11-14 2016-10-25 Samsung Display Co., Ltd. Organic light emitting display and method for driving the same
KR20150074257A (en) * 2013-12-23 2015-07-02 엘지디스플레이 주식회사 Touch display device and method for driving the same
US9665220B2 (en) 2014-02-03 2017-05-30 Samsung Display Co., Ltd. Display apparatus and method for driving the same with increased touch recognition
US9600130B2 (en) 2015-01-15 2017-03-21 Samsung Display Co., Ltd. Liquid crystal display device and method of driving the same
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