KR101234217B1 - Liquid crystal display device and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a touch type liquid crystal display device and a driving method thereof for detecting the position of the touched portion by the light sensing method. A liquid crystal display device according to the present invention comprises: a liquid crystal display panel including a gate line and a data line formed to cross each other; A data driver connected to the data line to supply a data signal to the data line; A gamma voltage supply unit supplying a gamma voltage corresponding to the grayscale values of black (0) to white (255) to the data driver; And a timing controller for supplying a control signal for controlling the data driver to the data driver, wherein the data driver includes a gray level value corresponding to the image signals R, G, and B input from the outside in response to the control signal of the timing controller. The gamma voltage is converted into a data signal and supplied to the data line, and the timing controller uses the gray level of white 255 when a gamma voltage corresponding to the gray value of the black series (0 to 125) is selected and applied to the data line. And controlling the data driver so that a data signal having a gamma voltage corresponding to the value is applied to the data line at least once. As a result, even when a black signal is applied to a region to be touched while the external environment is dark, the touched portion can be easily detected.

Description

Liquid crystal display and its driving method {LIQUID CRYSTAL DISPLAY DEVICE AND DRIVING METHOD THEREOF}

1 is a layout view of a thin film transistor substrate of a liquid crystal display device according to the present invention;

FIG. 2 is a cross-sectional view taken along II-II of FIG. 1;

3 is a cross-sectional view taken along line III-III of FIG. 1;

4 is a cross-sectional view taken along line IV-IV of FIG. 1;

5 is an equivalent circuit diagram for explaining a liquid crystal display device according to the present invention;

6 is a block diagram schematically showing a liquid crystal display device according to the present invention;

7A to 7D are views for explaining a position detection principle of the liquid crystal display according to the present invention.

8A to 8C are graphs for describing a method of driving a liquid crystal display device according to another embodiment;

9 is a graph for explaining a method of driving a liquid crystal display according to another exemplary embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: liquid crystal display panel 20: data driver

30: first gate driver 35: second gate driver

40: readout integrated circuit 50: analog-to-digital converter

60: gamma voltage supply unit 70: system

80: timing controller 90: power supply

95: digital / digital converter 100: thin film transistor substrate

The present invention relates to a driving method of a touch type liquid crystal display device, and more particularly, to a touch type liquid crystal which can easily detect a touched part even when a black signal is applied to a region to be touched while the external environment is dark. A method of driving a display device.

In general, a liquid crystal display device is an apparatus for displaying an image by adjusting the transmittance of the liquid crystal using an electric field. To this end, the liquid crystal display includes a liquid crystal display panel in which liquid crystal cells are arranged in a matrix, and a driving circuit unit for driving the liquid crystal display panel. In general, such a liquid crystal display device displays a desired image by converting a signal input by an external input means such as a keyboard into an image signal and a control signal in a driving circuit unit and applying the same to a liquid crystal display panel.

Recently, a touch type liquid crystal capable of contacting a person's hand or an object with a character or a specific position displayed on a screen of a liquid crystal display panel without using a separate input means such as a keyboard and identifying the position and processing by stored software Many display devices are being developed.

The touch type liquid crystal display is classified into a resistive film type, a capacitive type, a photo sensing type, and the like according to a method of detecting a contact position of a human hand or an object.

Here, the light sensing method detects a position where an object or the like touches by using light of a light source irradiated from the rear of the liquid crystal panel or detects a position of the touched part by detecting a shadow of an object or the like by external light. . The driving principle of the light-sensing touch type liquid crystal display device is as follows. In addition to the switching thin film transistor on one pixel, as the light is irradiated, a thin film transistor for the optical sensor through which the photo current flows is further formed. do. That is, when an object or the like is in contact with the liquid crystal panel, the light irradiated from the light source passes through the liquid crystal panel and is reflected by the object to be incident on the thin film transistor for the optical sensor. Such light causes a photocurrent to flow through the thin film transistor for the optical sensor. This photocurrent is a kind of light sensing signal, which is information corresponding to the corresponding position. In addition, a method of using external light is as follows. When touched, the liquid crystal panel is covered by an object. Since the external light is not incident on the part of the liquid crystal panel covered by the object, the thin film transistor for the optical sensor there is a difference from the thin film transistor for the optical sensor. The position of the touched part is detected by using.

That is, in the light sensing touch type liquid crystal display device, in order to detect the position of the touched part, the difference in luminance between the touched part and the peripheral part is important.

However, when the external light is not bright enough and the black signal is applied to the area to be touched, there is a problem in that the touched part and the light quantity (luminance) incident to the peripheral part thereof are insufficient, so that the location of the touched part cannot be easily detected. have. In detail, when a black signal is applied, all of the light projected from the light source to the liquid crystal panel is blocked by the liquid crystal molecules so that the light is not reflected to the object, and the external light is not bright. As a result, the difference in luminance between the touched part and the peripheral part is insufficient. Accordingly, there is a problem in that the position of the touched part cannot be easily detected.

Accordingly, an object of the present invention is to provide a liquid crystal display device which can easily detect a touched part even when a black signal is applied to a region to be touched while the external environment is dark.

The present invention also provides a method of driving a liquid crystal display device that can easily detect a touched part even when a black signal is applied to a region to be touched while the external environment is dark.

According to the present invention, there is provided a liquid crystal display panel including a gate line and a data line formed to cross each other; A data driver connected to the data line to supply a data signal to the data line; A gamma voltage supply unit supplying a gamma voltage corresponding to the grayscale values of black (0) to white (255) to the data driver; And a timing controller for supplying a control signal for controlling the data driver to the data driver, wherein the data driver includes gray level values corresponding to image signals R, G, and B input from the outside in response to the control signal of the timing controller. The gamma voltage is converted into a data signal and supplied to the data line. When the gamma voltage corresponding to the gray value of the black series (0 to 125) is selected and applied as the data signal, the timing controller selects And a data driver controlling the data driver so that a data signal of a gamma voltage corresponding to the gray scale value is applied to the data line at least once.

Here, the data line is supplied to the data line at 30 Hz or more, and the timing controller may control the data driver to supply the data line having a gamma voltage corresponding to the grayscale value of the white 255 at least once for one second. .

When the data signal is supplied to the data line at 30 Hz or more, the timing controller may control the data driver to apply a data signal having a gamma voltage corresponding to the gray value of the white 255 to the data line twice for 1 second. have.

Also, the timing controller may control the data driver so that the two data signals are discontinuously applied to the data line.

The data line is supplied with a data signal at 60 frames per second, and 60 frames are the first section of the first frame to the 20th frame, the second section of the 21st frame to the 40th frame, and the 41st frame. The timing controller may control the data driver to apply a data signal having a gamma voltage corresponding to the gray value of the white 255 to at least two of the first to third sections. Can be.

The gate driver may further include a gate driver connected to the gate line to supply a scan pulse signal including a gate-on voltage or a gate-off voltage to the gate line according to a control signal of the timing controller. The liquid crystal display panel may be provided at an intersection of the gate line and the data line. A first thin film transistor, wherein the timing controller supplies a control signal for controlling the gate driver to the gate driver, and the data line when a data signal having a gamma voltage corresponding to the gray value of the white 255 is applied to the data line. The gate driver may be controlled to input a scan pulse signal having a gate-on voltage to the first thin film transistor connected to the first thin film transistor.

The liquid crystal display panel may further include a thin film transistor for a sensor that allows a photocurrent to flow according to the amount of light incident from the outside.

In addition, the liquid crystal display panel may further include a second thin film transistor connected to the thin film transistor for the sensor, a lead out line connected to the second thin film transistor, and a lead out integrated circuit connected to the lead out line.

According to the present invention, another object of the present invention is to provide a liquid crystal display panel in which a data line is provided, a data driver connected to the data line to supply a data signal, and a gray level of black (0) to white (255) in the data driver. A driving method of a liquid crystal display device comprising a gamma voltage supply unit for supplying a gamma voltage corresponding to a value and a timing controller for supplying a control signal to a data driver, the data method comprising: When the corresponding gamma voltage is selected and applied as the data signal, the data signal of the gamma voltage corresponding to the grayscale value of the white 255 is applied to the data line at least once. do.

Here, when the data signal is supplied to the data line at 30 Hz or more, a data signal having a gamma voltage corresponding to the gray value of the white 255 may be supplied to the data line at least once for one second.

When a data signal is supplied to the data line at 30 Hz or more, a data signal having a gamma voltage corresponding to the gray value of the white 255 may be applied to the data line twice for one second.

In addition, a data signal is supplied to the data line at 60 frames per second, and 60 frames are the first section of the first frame to the 20th frame, the second section of the 21st frame to the 40th frame, and the 41st frame. The gamma voltage data signal corresponding to the gray value of the white 255 may be applied to at least two of the first to third sections.

Here, the data driver may convert the gamma voltage of the grayscale value corresponding to the image signals R, G, and B input from the outside into a data signal in response to a control signal of the timing controller, and supply the converted data signal to the data line.

The liquid crystal display panel further includes a gate line intersecting the data line, and a first thin film transistor formed at an intersection point of the gate line and the data line, and connected to the gate line to the gate line according to a control signal of the timing controller. The gate driver may further include a gate driver configured to supply a scan pulse signal having an off voltage. When the data signal is applied, the scan pulse signal having the gate-on voltage may be input to the first thin film transistor connected to the data line.

Hereinafter, a liquid crystal display and a driving method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

In general, the liquid crystal display device includes a liquid crystal display panel including a thin film transistor substrate 100, a color filter substrate (not shown), and a liquid crystal (not shown) positioned between both substrates. The rear of the liquid crystal display panel includes a backlight unit for supplying uniform light to the rear surface of the liquid crystal display panel, and a driving circuit unit for driving the liquid crystal display panel. Here, since the color filter substrate, the liquid crystal, and the backlight unit have the same configuration and function as in the prior art, description thereof will be omitted.

1 is a layout view of a thin film transistor substrate 100 constituting a light sensing type liquid crystal display device. 2, 3, and 4 are cross-sectional views taken along the line II-II, III-III, and IV-IV of FIG. 1, respectively.

As shown in FIG. 1, the thin film transistor substrate 100 according to the present invention includes a first thin film transistor T1, a thin film transistor T2 for a sensor, a second thin film transistor T3, and the like on an insulating substrate 110. Is formed.

Specifically, the first and second gate lines 121 and 128 are formed on the insulating substrate 110, and the first and second gate lines 121 and 128 are formed between the first and second gate lines 121 and 128. The first driving voltage line 125 and the second driving voltage line 126 are arranged in parallel with the 121 and 128. The gate electrodes 122 and 129 forming the first thin film transistor T1 are branched from the first gate line 121 and the second gate line 128, and the second driving voltage line 126 is branched. The width is provided in the pixel area. Here, the first and second gate lines 121 and 128, the first and second driving voltage lines 125 and 126, and the gate electrodes 122 and 129 may be a metal single layer or multiple layers. For example, molybdenum, Manganese, nickel, alloys thereof, and the like.

The gate insulating layer 130 is coated on the first and second gate lines 121 and 128, the first and second driving voltage lines 125 and 126, and the gate electrodes 122 and 129 described above. The gate insulating layer 130 may be an inorganic insulating layer such as SiO 2 or SiNx or may be formed of an organic insulating layer. The gate insulating layer 130 includes first and second insulating film contact holes 131 and 132 exposing portions of the first driving voltage line 125 and the second driving voltage line 126.

The semiconductor layers 141, 142, and 143 are formed in regions in which the first thin film transistor T1, the sensor thin film transistor T2, and the second thin film transistor T2 are to be formed on the gate insulating layer 130. An ohmic contact layer 150 made of a material such as n + hydrogenated amorphous silicon in which silicide or n-type impurities are heavily doped is formed on the semiconductor layers 141, 142, and 143. As shown in FIGS. 2, 3, and 4, the ohmic contact layer 150 is divided into two parts around the gate electrode 122.

Data lines 161 intersecting the first and second gate lines 121 and 128 and lead-out lines disposed parallel to the data lines 161 on the ohmic contact layer 150 and the gate insulating layer 130. The first source electrode 162 centered on the first source electrode 162 and the gate electrode 122 branched from the data line 161 to partially overlap the read-out line 165 and the gate electrode 122. The second source electrode 166 and the semiconductor layer 143 branched from the lead-out line 165 to partially overlap the first drain electrode 163 and the semiconductor layer 143 separated from the second drain electrode 163 and the semiconductor layer 143. The second drain electrode 167 spaced apart from the source electrode 126, the sensor source electrode 164 and the first storage electrically connected to the first driving voltage line 125 and extending onto the semiconductor layer 142. An upper electrode layer 168 for forming the capacitor CST1 is formed. Here, the second drain electrode 167 extends to the sensor thin film transistor T2 while overlapping the first and second driving voltage lines 125 and 126. One end of the second drain electrode 167 serves as a drain electrode of the second thin film transistor T3, and the other end has a 'U' shape to serve as a drain electrode of the sensor thin film transistor T2.

On these, a protective film 170 made of an organic material or an inorganic material is formed. The passivation layer 170 includes a first contact hole 171 exposing a part of the first drain electrode 163, a second contact hole 172 exposing a part of the upper electrode layer 168, and a source electrode 164 for the sensor. The third contact hole 173 exposing a part of the C) is formed.

The pixel electrode 180 made of a transparent electrode material is formed on the passivation layer 170. The pixel electrode 180 is connected to the first drain electrode 163 through the first contact hole 171. A portion of the pixel electrode 180 is connected to the upper electrode layer 168 through the second contact hole 172. Although not shown, the pixel electrode 180 generates a potential difference from a common electrode (not shown) formed on the curly filter substrate due to the charged pixel voltage. Due to this potential difference, the liquid crystal positioned between the thin film transistor substrate 100 and the color filter substrate (not shown) is rearranged by the dielectric anisotropy to adjust the light transmittance. The first transparent electrode layer 181 and the second transparent electrode layer 182 formed at the same time as the pixel electrode 180 are disposed on the passivation layer 180. The first transparent electrode layer 181 connects the sensor source electrode 164 and the first driving voltage line 125 through the third contact hole 173 and the first insulating layer contact hole 131. The second transparent electrode layer 182 is connected to the second driving voltage line 126 through the second gate contact hole 126.

As described above, the gate electrode 122, the semiconductor layer 141, the first source electrode 162, and the first drain electrode 163 constitute the first thin film transistor T1. A portion of the second driving voltage line 126, the semiconductor layer 142, the sensor source electrode 164, and the second drain electrode 167 form the thin film transistor T2 for the sensor. In addition, one end of the second gate line 128, the semiconductor layer 143, the second source electrode 166, and the second drain electrode 167 constitute the second thin film transistor T2.

In the first thin film transistor T1, a pixel voltage supplied to the data line 161 is charged to the pixel electrode 180 in response to a gate signal supplied to the gate line 121, which is applied to the first storage capacitor CST1. To be maintained. The thin film transistor T2 for the sensor is positioned between the first driving voltage line 125 and the second driving voltage line 126 and supplies the first and second driving voltages from the first and second driving voltage lines 125 and 126. Receive. The sensor thin film transistor T2 serves to sense light incident by an object or a human hand.

In addition, the second driving voltage line 126 and the upper electrode layer 168 overlapping each other with the gate insulating layer 130 interposed therebetween form a first storage capacitor CST1. The upper electrode layer 168 is connected to the pixel electrode 180 connected through the second contact hole 172. The first storage capacitor CST1 maintains the pixel voltage charged in the pixel electrode 180 until the pixel voltage charged in the pixel electrode 180 is charged to the next pixel voltage.

The second storage capacitor CST2 is connected to the thin film transistor T2 for the sensor. The second storage capacitor CST2 includes at least three capacitors CST2-1, CST2-2, and CST2-3. As illustrated in FIG. 4, the second storage capacitor CST2 is formed between the second driving voltage line 126 and the second drain electrode 167 overlapping each other with the gate insulating layer 130 interposed therebetween. A second-2 storage capacitor CST2- formed between the first driving voltage line 125 and the second drain electrode 167 overlapping each other with the storage capacitor CST2-1 and the gate insulating layer 130 interposed therebetween. 2) and a second-3 storage capacitor CST2-3 formed between the second drain electrode 167 and the second transparent electrode layer 182 overlapping each other with the passivation layer 170 therebetween. Here, the second storage capacitor CST2 is connected to the source electrode of the second thin film transistor T3 and the drain electrode of the sensor thin film transistor T2 (second drain electrode 167), respectively. The second storage capacitor CST2 stores a charge due to a photo current generated in the sensor thin film transistor T2.

Hereinafter, a light sensing process in the liquid crystal display device configured as described above will be described with reference to the equivalent circuit diagram of FIG. 5.

First, the second driving voltage line 126 is applied to the sensor source electrode 164 of the thin film transistor T2 and serves as a gate electrode of the thin film transistor T2 for the sensor. The second driving voltage Vbias is applied. The first driving voltage Vdrv is applied to the sensor source electrode 164 through the first transparent electrode layer 181 connected to the first driving voltage line 125. In this situation, when a predetermined light is sensed on the semiconductor layer 142 of the sensor thin film transistor T2, the second drain electrode 167 via a channel in the sensor source electrode 164 according to the sensed light amount. Photo Current Pass is generated flowing to the other end of the circuit. The photocurrent flows from the other end of the second drain electrode 167 to one end. Accordingly, charges are charged in the above-described three types of second storage capacitors CST2. The charge charged in the second storage capacitor CST2 is read by the read-out integrated circuit through the second thin film transistor T3 and the lead-out line 165. That is, since the signal detected by the readout integrated circuit according to the amount of light sensed by the sensor thin film transistor T2 is changed, the position of the touched part can be detected. The coordinates of the touched part are input to the controller to implement an image according to pre-stored software.

Hereinafter, the driving of the liquid crystal display device having the thin film transistor substrate 100 described above will be described with reference to FIG.

In the liquid crystal display according to the present invention, as shown in FIG. 6, the data driver 20 for supplying a data signal to the liquid crystal display panel 10 and the data lines DL1 to DLm of the liquid crystal display panel 10. ), A first gate driver 30 for supplying a scan pulse signal to the gate lines GL1 to GLn, and a second gate driver for supplying a second driving voltage Vbias to the second driving voltage lines SL1 to SLn. 35) from a read out integrated circuit (Read Out IC) 40 to which read out lines (RL1 to RLm) of the liquid crystal display panel 10 are commonly connected, and from the lead out integrated circuit 40. An analog-to-digital converter (ADC) 50 for converting an analog voltage into a digital signal, a gamma voltage supply unit 60 for supplying a plurality of gamma voltages to the data driver 20, and a system 70 To control the data driver 20 and the gate driver 30 by using a synchronization signal supplied from And a timing controller 80, a power supply DC / DC conversion unit 95 for generating voltages supplied to the liquid crystal display panel 10 by using the voltage supplied from the 90. The

The system 70 supplies the vertical / horizontal synchronization signals Vsync and Hsync, the clock signal DCLK, the data enable signal DE, and the image signals R, G, and B to the timing controller 80.

The gamma voltage supply unit 60 supplies a plurality of gamma voltages to the data driver 20. The gamma voltage supplier 60 supplies the gamma voltage corresponding to the grayscale values of black (0) to white (255) to the data driver 20. That is, the gamma voltage supply unit 60 separates black from white into 266 gray levels (0 to 255), generates a gamma voltage corresponding to each gray level, and transmits the gamma voltage to the data driver 20. Here, the gray value of the black series means that when the gamma voltage is applied to the data lines DL1 to DLm through the data driver 20 when the external environment is dark (low illumination), the external environment and the data lines DL1. It is a gradation value corresponding to a gamma voltage that is difficult to grasp the position of the touched part during touch input because the luminance division of the screen of the pixel connected to dlm is not clear. For example, the gamma voltage may correspond to approximately 0 to 125. These figures are approximate and may vary depending on the brightness of the external environment.

The data driver 20 converts the image signals R, G, and B into analog gamma voltages (data signals) corresponding to the gray scale values in response to the control signal CS from the timing controller 80. The voltage is supplied to the data lines DL1 to DLm. For example, the data driver 20 may supply a data signal at 60 Hz to the data lines DL1 to DLm.

The first gate driver 30 sequentially supplies scan pulse signals to the gate lines GL1 to GLn in response to the control signal CS from the timing controller 80, and is connected to the gate lines GL1 to GLn. The thin film transistor T1 (see FIG. 1) is sequentially turned on. In this case, the scan pulse signal includes a gate on voltage and a gate off voltage.

The readout integrated circuit 40 reads the sensing voltage supplied to the leadout line 165 (see FIG. 1) by being sensed by the sensor thin film transistor T2 (see FIG. 1) and initializes the second storage capacitor CST2. Play a role.

The analog-to-digital converter (ADC) 50 converts the analog sensing voltage from the readout integrated circuit 40 into a digital signal and supplies the changed digital signal to the timing controller 80.

The timing controller 80 controls the first gate driver 30 and the data driver 20 by using the vertical / horizontal synchronization signals Vsync and Hsync and the clock signal DCLK input from the system 70. Generate signal CS. Here, the control signal CS for controlling the first gate driver 30 includes a gate start pulse (GSP), a gate shift clock (GSC), and a gate output signal (GOE). ), And the like. The control signal CS for controlling the data driver 20 includes a source start pulse SSP, a source shift clock SSC, a source output enable SOE, Polarity signal (POL) and the like. The timing controller 80 rearranges and supplies the image signals R, G, and B supplied from the system 70 to the data driver 20. In addition, the timing controller 80 receives a digital signal from an analog-to-digital converter (ADC) 50, controls the readout integrated circuit 40 to supply a reset voltage Vreset, and a second A second gate driver for supplying the second driving voltage Vbias to the second driving voltage line 126 (see FIG. 1) serving as the gate electrode of the sensing thin film transistor T2 via the driving voltage lines SL1 to SLn ( 35).

In particular, in the timing controller 90 according to the present invention, when the gamma voltage corresponding to the gray value of the black series 0 to 125 is selected and applied as the data signal to the data lines DL1 to DLm, the white 255 is applied. The data driver 20 is controlled such that a data signal of a gamma voltage corresponding to the gray scale value of is applied to the data lines DL1 to DLm at least once. Here, the data signal in which the gamma voltage corresponding to the gray value of the black series 0 to 125 is selected is defined as a black signal, and the data signal of the gamma voltage corresponding to the gray value of the white 255 is defined as a white signal.

For example, the timing controller 90 transmits the white signal to the data lines DL1 to DLm at least once (60 frames) at 60 Hz while the black signal is being applied to the data lines DL1 to DLm at 60 Hz. The data driver 20 is controlled to be applied. That is, when all or part of a pixel connected to the data lines DL1 to DLm is viewed as a black series image, at least one frame of 60 frames per second is inverted to white.

The reason for such driving is as follows. In the case where the external environment is dark, when the black series image is implemented on the screen, the difference in the luminance between the screen and the external environment is not clear, and thus the probability of malfunction such as failing to detect the position of the touched part during touch input is determined. It is to minimize. That is, when the external light is not bright enough and the black series image is implemented in the area to be touched of the liquid crystal display panel 10, the difference between the touched part and the amount of light (luminance) incident on the peripheral part is insufficient. It is to solve the problem of not easily detecting the position.

When driven in accordance with the present invention, even when the black series screen is implemented, as shown in FIG. 7A, the difference in luminance between the peripheral area and the area to be touched is clear as the black series screen is inverted to white at least once in 60 frames. It is done. As a result, accurate positioning of the touched portion becomes possible.

That is, as shown in FIG. 7B, even when the touch screen 200 approaches the liquid crystal display panel 210 when the black series screen is implemented, all the light projected from the light source 230 to the liquid crystal display panel 210 is liquid crystal. Since it is blocked by the molecules and cannot be reflected by the touch fan 200, and the external light is not bright, the part of the liquid crystal display panel 210 covered by the touch fan 200 is also not clearly distinguished from its periphery and thus the touched part and its periphery. The difference in luminance becomes insignificant.

However, when the black series screen is inverted to the white screen at least one frame out of 60 frames, as shown in FIG. 7C, the light of the light source 230 passes through the liquid crystal display panel 210 and the touch fan 200. ) Is reflected. The reflected light is introduced into the thin film transistor T2 (see FIG. 1) to allow position detection.

Then, as shown in Fig. 7D, the screen is inverted again to the black series.

As described above, since the black series screen is inverted to the white screen at a high speed of 1/60 second among the 1 second, the user's eyes are still recognized as black so that a visual problem does not occur. However, the sensor thin film transistor T2 (see FIG. 1) is provided with an opportunity for light to be introduced, thereby enabling position detection.

In another embodiment, the timing controller 80 may control the data driver 20 to supply the white signal to the data lines DL1 to DLm of about 60 frames. This is to secure the reliability of the touch type liquid crystal display device by increasing the probability of detecting the position of the portion to be touched even when the external environment is dark. That is, when only one frame out of 60 frames is supplied to the data lines DL1 to DLm as a white signal, and the black frame is supplied to the data lines DL1 to DLm as a 59 signal, according to changes in the external environment or other factors. It may be difficult to detect the position of the touched part because the difference in luminance between the touched part and the peripheral part is not clear. In case of such a case, the white signal is controlled to be supplied to the data lines DL1 to DLm twice for 60 Hz.

Here, it is preferable that the two white signals are supplied to the data lines DL1 to DLm discontinuously. For example, as shown in FIGS. 8A to 8C, a data signal is supplied to the data line at 60 frames per second, and 60 frames are the first section a of the first to 20th frames. And the second section (b) of the twenty-first frame to the forty frame and the third section (c) of the forty-first frame to the sixty frame, and the timing controller 80 includes the first section (a) to the first section. It is preferable that the data signals of the gamma voltage corresponding to the gray value of the white 255 are respectively applied to two of the three sections c. Alternatively, although not shown in another embodiment, three white signals may be supplied to the data lines DL1 to DLm, and the three white signals may be provided in the first section (a), the second section (b), and the third section. It may be applied in the interval (c).

However, it is not preferable that the white signal is applied to the data lines DL1 to DLm too many times. This is because a desired black series screen may not be implemented.

Meanwhile, when a white signal is applied to the data lines DL1 to DLm, the timing controller 80 may include a gate-on voltage gate to a first thin film transistor T1 (see FIG. 1) connected to the data lines DL1 to DLm. The first gate driver 30 is controlled to input a scan pulse signal of an on pulse. This is to allow a screen of white to be normally implemented in pixels connected to the data lines DL1 to DLm to which the white signal is applied.

The digital / digital converter 95 boosts or decompresses a VCC voltage of 3.3 V input from the power supply unit 90 to generate a voltage supplied to the liquid crystal display panel 10. That is, the VCC voltage of 3.3V input from the power supply unit 90 is boosted or reduced to supply the reference voltage VDD, and the common voltage Vcom is generated to generate the common voltage Vcom to pass through the liquid crystal display panel 20. To 10).

Hereinafter, another embodiment of the present invention will be described with reference to FIG. 9 is a case where a data signal is supplied to a data line at 30 Hz, unlike the above-described embodiment.

When a data signal is supplied to the data line at 30 Hz, the timing controller 80 (see FIG. 6) may control the data driver 20 (see FIG. 6) so that a white signal is applied to at least one of the 30 frames. Although not shown, a white signal may be applied to two frames out of 30 frames. In this case, the two frames are preferably discontinuous rather than continuous. At 30Hz operation, two white signal feeds are not detected by the user's eyes.

However, when the white signal is applied more than once in the driving of 30 Hz or less, the screen inverting to white may be visually recognized and may be annoying to the user.

On the other hand, although not specifically described, the technical spirit of the present invention is not limited to the above-described embodiment. That is, the technical idea of the present invention is not limited to driving at 30 Hz and 60 Hz, and at least one frame or more when a black signal is applied to a region to be touched to improve the touch sensitivity of all touch type liquid crystal display devices driven at 30 Hz or higher. The control is to apply a white signal.

As described above, according to the present invention, there is provided a liquid crystal display device which can easily detect a touched part even when a black signal is applied to a region to be touched while the external environment is dark.

In addition, a method of driving a liquid crystal display device capable of easily detecting a touched part even when a black signal is applied to a region to be touched while the external environment is dark is provided.

Claims (14)

A liquid crystal display panel including a gate line and a data line formed to cross each other; A data driver connected to the data line to supply a data signal to the data line; A gamma voltage supply unit supplying a gamma voltage corresponding to a gray value of black (0) to white (255) to the data driver; A timing controller for supplying a control signal for controlling the data driver to the data driver, The data driver converts a gamma voltage of a gray value corresponding to an image signal (R, G, B) input from the outside into a data signal and supplies the converted data signal to the data line in response to a control signal of the timing controller. When the gamma voltage corresponding to the gray value of the black series 0 to 125 is selected and applied to the data line as the data signal, the timing controller displays a data signal of the gamma voltage corresponding to the gray value of the white 255. And controlling the data driver to be applied at least once to a line. The method of claim 1, The data line is supplied with a data signal at 30 Hz or more, And the timing controller controls the data driver to supply a data signal of a gamma voltage corresponding to the grayscale value of white (255) at least once for one second to the data line. 3. The method of claim 2, When a data signal is supplied to the data line at 30 Hz or more, And the timing controller controls the data driver to apply a data signal of a gamma voltage corresponding to a gray value of white (255) to the data line twice for one second. The method of claim 3, And the timing controller controls the data driver so that the two data signals are discontinuously applied to the data line. The method of claim 1, The data line is supplied with a data signal at 60 frames per second, The 60 frame is divided into a first section of the first frame to the 20th frame, a second section of the 21st frame to 40th frame and a third section of the 41st frame to the 60th frame, And the timing controller controls the data driver to apply a data signal having a gamma voltage corresponding to the grayscale value of white (255) to at least two of the first to third sections. The method of claim 1, A gate driver connected to the gate line to supply a scan pulse signal having a gate on voltage or a gate off voltage to the gate line according to a control signal of the timing controller, The liquid crystal display panel includes a first thin film transistor formed at an intersection point of the gate line and the data line. The timing controller is configured to supply a control signal for controlling the gate driver to the gate driver and, when a data signal having a gamma voltage corresponding to a gray value of white 255 is applied to the data line, connected to the data line. And controlling the gate driver to input a scan pulse signal having a gate-on voltage to a thin film transistor. The method of claim 1, The liquid crystal display panel further comprises a thin film transistor for a sensor for flowing a photo current according to the amount of light incident from the outside. The method of claim 7, wherein The liquid crystal display panel further includes a second thin film transistor connected to the thin film transistor for the sensor, a lead out line connected to the second thin film transistor, and a lead out integrated circuit connected to the lead out line. A liquid crystal display device. A liquid crystal display panel provided with a data line, a data driver connected to the data line to supply a data signal, and a gamma to supply a gamma voltage corresponding to the gray value of black (0) to white (255) to the data driver. A driving method of a liquid crystal display device comprising a voltage supply unit and a timing controller supplying a control signal to the data driver. When a gamma voltage corresponding to the gray value of the black series 0 to 125 is selected and applied as the data signal to the data line, a data signal of the gamma voltage corresponding to the gray value of the white 255 is at least included in the data line. A method of driving a liquid crystal display, characterized in that it is applied once. 10. The method of claim 9, When a data signal is supplied to the data line at 30 Hz or more, a data signal having a gamma voltage corresponding to the gray value of the white 255 is supplied to the data line at least once for one second. Way. The method of claim 10, When a data signal is supplied to the data line at 30 Hz or higher, a data signal having a gamma voltage corresponding to the gray value of the white 255 is applied to the data line twice for 1 second. Way. 10. The method of claim 9, The data line is supplied with a data signal at 60 frames per second, The 60 frame is divided into a first section of the first frame to the 20th frame, a second section of the 21st frame to 40th frame and a third section of the 41st frame to the 60th frame, And a data signal of a gamma voltage corresponding to the grayscale value of white (255) is applied to at least two of the first to third sections, respectively. 10. The method of claim 9, The data driver converts a gamma voltage of a gray value corresponding to an image signal (R, G, B) input from the outside into a data signal and supplies the converted data signal to the data line in response to a control signal of the timing controller. Driving method of liquid crystal display device. 10. The method of claim 9, The liquid crystal display panel further includes a gate line crossing the data line, and a first thin film transistor formed at an intersection point of the gate line and the data line. A gate driver connected to the gate line to supply a scan pulse signal having a gate on voltage or a gate off voltage to the gate line according to a control signal of the timing controller, The timing controller supplies a control signal for controlling the gate driver to the gate driver, When a data signal of a gamma voltage corresponding to the gray value of the white 255 is applied to the data line, a scan pulse signal of a gate-on voltage is input to the first thin film transistor connected to the data line. Driving method of liquid crystal display device.

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