KR101495347B1 - Liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal display device which simplifies an algorithm of touch recognition and improves the reliability of touch recognition.

The liquid crystal display device has a plurality of pixels including a pixel circuit and a touch sensor circuit that generates a photocurrent differently depending on whether a pixel circuit is touched at intersecting regions of gate lines and data lines and displays normal data RGB A liquid crystal display panel displaying black data (BD) during a second period subsequent to the first period; A backlight unit for irradiating light to a back surface of the liquid crystal display panel during the first period and the second period, a lead-out integrated circuit for converting the photocurrent from the touch sensor circuit into light sensing data; Wherein the photo sense data stored in the memory is stored in the memory after storing the photo sense data supplied from the lead-out integrated circuit during the first period and from the lead-out integrated circuit during the second period, A touch position information detection circuit for extracting a difference value between supplied light sensing data and generating touch position information excluding the influence of external light; And a system for performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm; The memory stores only the photo sensed data supplied from the lead-out integrated circuit during the first period, and does not store the photo sensed data supplied from the lead-out integrated circuit during the second period.

Touch sensor, BDI, external light, algorithm, simplification, backlight, flashing

Description

[0001] The present invention relates to a liquid crystal display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device of a touch panel in cell type, and more particularly to a liquid crystal display device which simplifies an algorithm of touch recognition and improves the reliability of touch recognition.

The liquid crystal display displays an image by controlling the light transmittance of the liquid crystal layer through an electric field applied to the liquid crystal layer in accordance with a video signal. Such a liquid crystal display device is a flat panel display device having advantages of small size, thinness and low power consumption, and is used as a portable computer such as a notebook PC, office automation equipment, audio / video equipment and the like. Particularly, an active matrix type liquid crystal display device in which a switching element is formed for each liquid crystal cell is capable of actively controlling a switching element, which is advantageous for a moving image.

A thin film transistor (hereinafter referred to as "TFT") is mainly used as a switching element used in an active matrix type liquid crystal display device as shown in Fig.

1, an active matrix type liquid crystal display device converts digital video data into an analog data voltage on the basis of a gamma reference voltage and supplies the analog data voltage to a data line DL, and simultaneously supplies a scan pulse to a gate line GL And charges the liquid crystal cell Clc with the data voltage. To this end, the gate electrode of the TFT is connected to the gate line GL, the source electrode thereof is connected to the data line DL, and the drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc and the storage capacitor Cst1 And is connected to one electrode. A common voltage Vcom is supplied to the common electrode of the liquid crystal cell Clc. The storage capacitor Cst1 functions to charge the data voltage applied from the data line DL when the TFT is turned on to maintain the voltage of the liquid crystal cell Clc constant. When a scan pulse is applied to the gate line GL, the TFT is turned on to form a channel between the source electrode and the drain electrode to apply a voltage on the data line DL to the pixel electrode of the liquid crystal cell Clc Supply. At this time, the liquid crystal molecules of the liquid crystal cell Clc are changed in arrangement by the electric field between the pixel electrode and the common electrode to modulate the incident light.

On the other hand, a liquid crystal display device is a passive light emitting device that adjusts brightness of a screen by using a backlight generated from a backlight unit disposed on the back surface of a liquid crystal display panel.

Recently, a technique of attaching a touch screen panel on such a liquid crystal display device has been proposed. A touch screen panel generally refers to a user interface that is attached to a display device and detects the touch point at a touch point that is in contact with an opaque object such as a finger or a pen. When a user's finger, touch pen, or the like touches the screen, the liquid crystal display with the touch screen panel detects the contact position information and can implement various applications based on the detected information have.

However, such a liquid crystal display device causes various problems such as a rise in cost due to a touch screen panel, a reduction in yield due to a process of adhering a touch screen panel on a liquid crystal display panel, a decrease in luminance of a liquid crystal display panel, and an increase in thickness.

In order to solve the above problems, a cell type which is a touch panel in which a touch sensor circuit including a sensor TFT as shown in Fig. 2 is formed in a liquid crystal cell Clc of a liquid crystal display device has been proposed instead of a touch screen panel . The touch sensor circuit includes a sensor TFT that generates a photocurrent i differently according to a change in the quantity of light incident from the outside, a sensor capacitor Cst2 that stores charges by the photocurrent i, And a switch TFT for switching the TFTs. A bias voltage Vbias set at a voltage equal to or lower than the threshold voltage of the sensor TFT is supplied to the gate electrode of the sensor TFT. In the touch sensor circuit, the photocurrent of the sensor TFT corresponding to the touched portion is larger than the photocurrent of the sensor TFT corresponding to the non-touched portion in a dark illumination environment (indoor environment) than the backlight, ), The photocurrent of the sensor TFT corresponding to the touched portion is different from the photocurrent of the sensor TFT corresponding to the non-touched portion, and the photodetection signals in the touched or untouched portions are generated differently. The liquid crystal display device can find the contact position information of the user's finger using the touch recognition algorithm operated based on the light sensing signal of the touch sensor circuit.

FIG. 3 shows a result of sensing a touched portion in a conventional liquid crystal display of a touch panel. In Fig. 3, "A" represents a touch point by a finger, "B" represents a portion where external light is blocked by a finger, and "C" Here, "A" has a data value brighter than "B " due to the reflection of the backlight due to the touch.

However, such a cell-type liquid crystal display device that is a touch panel is complicated in the touch recognition algorithm because it applies all of "A" to "C" to the algorithm in order to extract the touched portion. In order to extract the touched portion, the cell type liquid crystal display device such as this touch panel applies all of "A" to "C" to the algorithm. Therefore, when the data values of "A" and "C" A "and" C "are similar to each other, the reliability of the touch recognition deteriorates.

Accordingly, it is an object of the present invention to provide a liquid crystal display device which simplifies the algorithm of touch recognition and improves the reliability of touch recognition.

According to an aspect of the present invention, there is provided a liquid crystal display device including a plurality of pixels including a pixel circuit and a touch sensor circuit for generating a photocurrent differently depending on whether a pixel circuit is touched at intersecting areas of gate lines and data lines, A liquid crystal display panel displaying normal data (RGB) during a first period and displaying black data (BD) during a second period subsequent to the first period; A backlight unit for irradiating light to the back surface of the liquid crystal display panel during the first period and the second period; A lead-out integrated circuit for converting the photocurrent from the touch sensor circuit into light sensing data; Wherein the photo sense data stored in the memory is stored in the memory after storing the photo sense data supplied from the lead-out integrated circuit during the first period and from the lead-out integrated circuit during the second period, A touch position information detection circuit for extracting a difference value between supplied light sensing data and generating touch position information excluding the influence of external light; And a system for performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm; The memory stores only the photo sensed data supplied from the lead-out integrated circuit during the first period, and does not store the photo sensed data supplied from the lead-out integrated circuit during the second period.

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The liquid crystal display device and the driving method thereof according to the present invention can simplify the algorithm of touch recognition and greatly improve the reliability of the touch recognition.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 4 to 12. FIG.

4 is a block diagram illustrating a liquid crystal display device according to an embodiment of the present invention.

4, a liquid crystal display according to an exemplary embodiment of the present invention includes a plurality of gate lines G0 to Gn, a plurality of data lines D1 to Dm, and a plurality of driving voltage supply lines VL1 to VL1, A liquid crystal display panel 10 in which pixels P having a touch sensor circuit are disposed at intersections of the liquid crystal display panel 10 and the data lines D1 to Dm, A data driving circuit 20 for supplying a data voltage, a gate driving circuit 30 for supplying a scanning pulse to gate lines G1 to Gn, a data driving circuit 20 and a gate driving circuit 30, A driving voltage supply circuit 50 for supplying a driving voltage required for driving the touch sensor circuit to the driving voltage supply lines VL1 to VLn and a liquid crystal display panel 10, a backlight unit 6 0), a lead-out integrated circuit 70 for converting a photoelectric current from the touch sensor circuit into photo-sensing data LSdata, and first and second gate-start pulses A touch position information detection circuit 80 for generating touch position information XY in which the influence of external light is eliminated by using the light sensing data LSdata from the readout integrated circuit 70 and the touch position information XY, And a system 90 for applying the information XY to the touch recognition algorithm to perform a processor process for touch recognition.

The liquid crystal display panel 10 includes an upper substrate including a color filter, a lower substrate on which pixels P including a pixel circuit and a touch sensor circuit are formed, and a liquid crystal layer sandwiched between the upper substrate and the lower substrate .

A plurality of data lines D1 to Dm and a plurality of gate lines G0 to Gn are orthogonal to one another and a plurality of gate lines G0 to Gn parallel to the gate lines G0 to Gn are formed on a lower substrate of the liquid crystal display panel 10. [ A plurality of lead-out lines ROL1 to ROLm are formed which are orthogonal to the driving voltage supply lines VL1 to VLn, the gate lines G0 to Gn and the driving voltage supply lines VL1 to VLn. The intersection of the data lines D1 to Dm and the gate lines G1 to Gn is connected to the pixel circuit P1 (see FIG. 8) including the pixel TFT TFT1, the liquid crystal cells Clc and the storage capacitor Cst1, A sensor TFT S-TFT, a sensor capacitor Cst2 and a switch TFT (see FIG. 8) are formed at intersections of the drive voltage supply lines VL1 to VLn and the lead-out lines ROL1 to ROLm A touch sensor circuit P2 including TFT2 is formed. Each of the driving voltage supply lines VL1 to VLn includes a supply line for supplying a high potential driving voltage to the touch sensor circuit P2 and a supply line for supplying a bias voltage to the touch sensor circuit P2. The touch sensor circuit P2 generates a photocurrent differently depending on whether an opaque object such as a finger is touched (hereinafter referred to as "finger") and outputs the photocurrent through the lead-out lines ROL1 to ROLm 70).

On the upper substrate of the liquid crystal display panel 10, a black matrix for covering the boundary between the pixels P is formed. A common electrode to which a common voltage is supplied in opposition to the pixel electrode with the liquid crystal layer interposed therebetween is formed on the upper substrate in a vertical electric field mode such as TN (Twisted Nematc) mode and VA (Vertical Alignment) Mode and a FFS (Fringe Field Switching) mode.

The data driving circuit 20 outputs the normal data RGB and the black data BD in response to the data control signal DDC from the timing controller 40 to the gamma reference voltages (GMA), and supplies the analog gamma compensation voltage to the data lines D1 to Dm of the liquid crystal display panel 10 as a data voltage.

The gate driving circuit 30 generates a scan pulse in response to the gate control signal GDC from the timing controller 40 and sequentially supplies the scan pulse to the gate lines G1 to Gn to supply the data voltage The horizontal line of the liquid crystal display panel 10 is selected.

The timing controller 40 generates black data BD for impulse driving and rearranges the black data BD and the normal data RGB from the system 90 according to the liquid crystal display panel 10, (20). The timing controller 40 includes a data control signal DDC for controlling the data driving circuit 20 using the timing control signals Vsync, Hsync, DCLK and DE from the system 90, And generates a gate control signal GDC for controlling the gate 30.

The data control signal DDC includes a source sampling clock (SSC) for instructing a latch operation of data in the data driving circuit 20 based on a rising or falling edge, a data driving circuit And a polarity control signal POL indicating the polarity of the data voltage to be supplied to the liquid crystal cells Clc of the liquid crystal display panel 10 and the like .

The gate control signal GDC is input to a shift register in the gate driving circuit 30, a gate start pulse (GST) indicating a starting horizontal line at which the scanning starts in one frame period in which one screen is displayed, A gate shift clock signal (GSC) generated with a pulse width corresponding to the ON period of the pixel TFT as a timing control signal for sequentially shifting the start pulse GSP, and a gate drive clock signal And a gate output enable (GOE) signal indicating the output of the gate output enable signal (GOE). 5, the gate start pulse GSP includes a first gate start pulse GSP1 indicating a scan start horizontal line of normal data RGB in one frame period, And a second gate start pulse GSP2 indicating a scan start horizontal line.

The driving voltage supply circuit 50 generates a high potential driving voltage and a bias voltage necessary for driving the touch sensor circuit P2 and supplies the high potential driving voltage and the bias voltage to the driving voltage supply lines VL1 to VLn.

The backlight unit 60 includes a plurality of lamps which are installed on the back surface of the liquid crystal display panel 10 so as to overlap with the liquid crystal display panel 116. The lamp used in the backlight unit 60 may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a heat cathode fluorescent lamp (HCFL) Lt; / RTI > The lamps irradiate light to the back surface of the liquid crystal display panel 10 by driving an inverter (not shown). On the other hand, the backlight unit 60 may have a plurality of light emitting diodes instead of or in combination with the lamps.

The lead-out integrated circuit 70 includes a plurality of circuits respectively connected to the lead-out lines ROL1 to RLOm of the liquid crystal display panel 10 and outputs the photocurrent from the lead-out lines ROL1 to RLOm, (LSdata), and supplies the converted data to the touch position information detection circuit 80.

The touch position information detection circuit 80 outputs the first and second gate start pulses GSP1 and GSP2 generated from the timing controller 40 for impulse driving and the light detection data LSdata from the leadout integrated circuit 70, To generate touch position information (XY) excluding the influence of external light. 6, the touch position information detection circuit 80 includes an RGB scan storage unit 82, a BD scan storage unit 84, and a difference value extraction unit 86. [

The RGB scan storage unit 82 stores the light sensing data LSdata supplied from the lead-out integrated circuit 70 during the first period T1 synchronized with the first gate start pulse GSP1 as shown in FIG. 5 . The information stored in the RGB scan storage unit 82 is shown in FIG. In FIG. 7A, " A "indicates information about a finger touch point," B "indicates information about a portion where external light is blocked by a finger, and" C & Respectively.

The BD scan storage unit 84 stores the light sensing data LSdata supplied from the lead-out integrated circuit 70 during the second period T2 synchronized with the second gate start pulse GSP2 as shown in FIG. 5 . The information stored in the BD scan storage unit 84 is shown in FIG. 7B. In Fig. 7B, "B" indicates information on a portion where external light is blocked by a finger, and "C"

The difference value extracting unit 86 compares the light sensed data from the RGB scan storage unit 82 and the BD scan storage unit 84 on a one-to-one basis and extracts the difference value of the compared data, And generates position information XY. As shown in FIG. 7C, the extracted difference value information includes only the information A about the touch point by the finger.

On the other hand, in the touch position information detection circuit 80, two memories 82 and 84 may be integrated into one memory in order to cope with the reduction in the number of memories. Using the integrated memory, the touch position information detection circuit 80 first stores the light sensing data LSdata supplied from the lead-out integrated circuit 70 during the first period T1, Subtracts the light sensing data LSdata supplied from the lead-out integrated circuit 70 during the second period T2 from the data LSdata and outputs the difference to the light sensing data LSdata stored during the first period T1 Overwrite can be done.

The system 90 converts analog image data supplied from the outside through an interface circuit (not shown) into digital normal data RGB and supplies the digital normal data RGB to the timing controller 40. The system 90 extracts the composite image signal using the image data from the interface circuit, and outputs a synchronizing signal (HV sync), a data enable signal (DE) and a dot clock (DCLK) to the timing controller (40).

In particular, the system 90 performs a processor process for touch recognition by applying the touch position information XY supplied from the touch position information detection circuit 80 to the touch recognition algorithm, including the touch algorithm processing unit 92 And reflects the execution result on the liquid crystal display panel 10 again. As described above, since the touch position information XY includes only the information about the touch point by the finger, the touch recognition algorithm built in the touch algorithm processing unit 92 can be greatly simplified compared to the conventional method. Since the touch position information XY includes only the information about the touch point by the finger, the reliability of the touch recognition can be greatly improved.

8 is an equivalent circuit diagram of the pixel P shown in Fig.

8, a pixel P includes a pixel circuit P1 formed at an intersection of a j-th gate line Gj and a j-th data line Dj, a j-th first supply line VLja, and j And a touch sensor circuit P2 formed at the intersection of the second supply line VLjb and the j-th lead-out line ROLj.

The pixel circuit P1 includes a liquid crystal cell Clc and a pixel TFT TFT1 formed in a crossing region of the gate line Gj and the data line Dj for driving the liquid crystal cell Clc, And a storage capacitor Cst1 for maintaining the charging voltage of the storage capacitor Cst1 for one frame.

The pixel TFT TFT1 supplies a data voltage supplied through the data line DLj to the pixel electrode of the liquid crystal cell Clc in response to a scan pulse from the gate line GLj. To this end, the gate electrode of the pixel TFT (TFT1) is connected to the gate line GLj, the source electrode thereof is connected to the data line DLj, and the drain electrode thereof is connected to the pixel electrode of the liquid crystal cell Clc. The liquid crystal cell Clc is charged with the potential difference between the data voltage and the common voltage Vcom, and the arrangement of the liquid crystal molecules is changed by the electric field formed by this potential difference to adjust the light amount of the transmitted light or block the light. The storage capacitor Cst1 is connected between the drain electrode of the pixel TFT (TFT1) and the second supply line (VLjb).

The touch sensor circuit P2 includes a sensor TFT (S-TFT) that generates a photocurrent i differently depending on whether or not the touch point corresponds to a period during which the driving voltage is supplied, a sensor And a switch TFT (TFT2) for switching the charges stored in the capacitor Cst2 and the sensor capacitor Cst2 to the lead-out line ROLj.

The gate electrode of the sensor TFT (S-TFT) is connected to the second supply line (VLjb), the source electrode is connected to the first supply line (VLja), and the drain electrode is connected to the first node (N1). A bias voltage Vbias set at a voltage equal to or lower than the threshold voltage of the sensor TFT (S-TFT) is supplied to the gate electrode of the sensor TFT (S-TFT), and a driving voltage is supplied to the source electrode of the sensor TFT (S-TFT). Since the sensor TFT (S-TFT) is not covered by the black matrix of the upper substrate, unlike the pixel TFT (TFT1) and the switch TFT (TFT2), the photoelectric current i), but generates a photocurrent (i) of different magnitude depending on whether or not the touch point is present. In other words, the sensor TFT (S-TFT) generates a large photocurrent (i) when it corresponds to the touch point, compared with when it does not correspond to the touch point in a dark illumination environment (indoor environment) (I) is generated when the touch point is not corresponded to the touch point in the case of the touch point (outdoor environment).

Charges by the photocurrent i are stored in the sensor capacitor Cst2 connected between the first node N1 and the second supply line VLjb. The voltage VN1 of the first node is gradually increased by the charges stored in the sensor capacitor Cst2 until the switch TFT TFT2 is turned on. The voltage VN1 at the first node has different magnitudes depending on whether or not the voltage corresponds to the touch point during the period in which the drive voltage is supplied. In other words, the voltage VN1 of the first node has a larger value when it corresponds to the touch point than when it does not correspond to the touch point in a dark illumination environment (indoor environment) than the backlight, ) Has a smaller value when corresponding to the touch point than when it is not corresponding to the touch point.

The gate electrode of the switch TFT TFT2 is connected to the (j-1) th gate line Gj-1, the source electrode thereof is connected to the first node N1, and the drain electrode thereof is connected to the lead-out line ROLj. The switch TFT TFT2 is turned on in response to the scan pulse SPj-1 supplied to the (j-1) th gate line Gj-1 to output the first node voltage VNl as the photo- .

9 is a block diagram illustrating a liquid crystal display device according to another embodiment of the present invention.

9, a liquid crystal display according to another embodiment of the present invention includes a plurality of gate lines G0 to Gn, a plurality of data lines D1 to Dm, and a plurality of driving voltage supply lines VL1 to VL1, A data driving circuit 120 for supplying a data voltage to the data lines D1 to Dm; a liquid crystal display panel 110 in which pixels P having a touch sensor circuit are arranged at intersections of the pixels P, A gate driving circuit 130 for supplying a scan pulse to the gate lines G1 to Gn and a timing controller 140 for controlling the driving timing of the data driving circuit 120 and the gate driving circuit 130, A driving voltage supply circuit 150 for supplying a driving voltage required for driving the touch sensor circuit to the driving voltage supply lines VL1 to VLn and a driving circuit for applying light to the back surface of the liquid crystal display panel 110 A backlight unit 160 for driving the touch sensor circuit 160, Out integrated circuit 170 for converting the photocurrent from the lead-out integrated circuit 170 to the photodetection data LSdata from the timing controller 140 for impulse driving, A touch position information detection circuit 180 which generates touch position information XY in which the influence of external light is eliminated by using data LSdata and a touch position information detection circuit 180 which applies touch position information XY to the touch recognition algorithm, And a system 190 for performing a processor process.

The liquid crystal display panel 110 and the driving voltage supply circuit 150 are substantially the same as those of the liquid crystal display panel 10 and the driving voltage supply circuit 50 shown in FIG. 4, respectively, so that a detailed description thereof will be omitted .

The data driving circuit 120 drives the digital video data RGB in response to the data control signal DDC from the timing controller 140 based on the gamma reference voltages GMA from the gamma reference voltage generator And supplies the analog gamma compensation voltage to the data lines D1 to Dm of the liquid crystal display panel 110 as a data voltage.

The gate driving circuit 130 generates a scan pulse in response to the gate control signal GDC from the timing controller 140 and sequentially supplies the scan pulse to the gate lines G1 to Gn to supply the data voltage The horizontal line of the liquid crystal display panel 110 is selected.

The timing controller 140 rearranges the digital video data RGB input from the system 190 according to the liquid crystal display panel 110 and supplies the digital video data RGB to the data driving circuit 120. The timing controller 140 includes a data control signal DDC for controlling the data driving circuit 120 using the timing control signals Vsync, Hsync, DCLK and DE from the system 190, A gate control signal GDC for controlling the inverter 130 and a backlight control signal SBL for controlling the backlight.

The data control signal DDC includes a source sampling clock (SSC) for instructing a latch operation of data in the data driving circuit 120 based on a rising or falling edge, a data driving circuit A polarity control signal POL indicating the polarity of a data voltage to be supplied to the liquid crystal cells Clc of the liquid crystal display panel 110, and the like, and the like .

The gate control signal GDC is input to a shift register in the gate driving circuit 130, a gate start pulse (GST) indicating a starting horizontal line at which scanning starts in one frame period in which one screen is displayed, A gate shift clock signal GSC generated with a pulse width corresponding to the ON period of the pixel TFT as a timing control signal for sequentially shifting the start pulse GSP, And a gate output enable (GOE) signal indicating the output of the gate output enable signal (GOE).

The backlight control signal SBL includes a plurality of control signals SBL1 to SBLk corresponding to the plurality of lamps L1 to Lk as shown in Figs. Each of the control signals SBL1 to SBLk corresponds to a lighting control signal BLon generated at a high logic level corresponding to a first period T1 in which the lamp is lit and a second period T2 during which the lamp is turned off And a light-off control signal BLoff generated at a low logic level. These control signals SBL1 to SBLk are sequentially generated with a predetermined phase shift value and then supplied to a plurality of inverters I1 to Ik connected in a one-to-one manner to the ramps L1 to Lk to implement impulse driving.

The backlight unit 160 includes a plurality of lamps that are installed on the back surface of the liquid crystal display panel 110 so as to overlap with the liquid crystal display panel 116. The lamp used in the backlight unit 160 may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a heat cathode fluorescent lamp (HCFL) . The lamps sequentially irradiate the backside of the liquid crystal display panel 110 with light that is sequentially flickered in response to the backlight control signal SBL from the timing controller 140. Meanwhile, the backlight unit 160 may include a plurality of light emitting diodes instead of or in combination with the lamps.

The lead-out integrated circuit 170 includes a plurality of circuits respectively connected to the lead-out lines ROL1 to RLOm of the liquid crystal display panel 110 and outputs the photocurrent from the lead-out lines ROL1 to RLOm, Converted into light detection data (LSdata) and supplied to the touch position information detection circuit 180.

The touch position information detection circuit 180 uses the backlight control signal SBL from the timing controller 140 and the light detection data LSdata from the lead-out integrated circuit 170 for impulse driving to eliminate the influence of external light And generates the touch position information XY. 12, the touch position information detection circuit 180 includes an on-scan storage section 182, an off-scan storage section 184, and a difference value extraction section 186. [

The lighting scan storage unit 182 stores the light sensing data LSdata supplied from the lead-out integrated circuit 170 during the first period T1 synchronized with the lighting control signal BLon shown in FIG. The information stored in the lighting scan storage unit 182 is shown in FIG. In FIG. 7A, " A "indicates information about a finger touch point," B "indicates information about a portion where external light is blocked by a finger, and" C & Respectively.

The extinction scan storage unit 184 stores the light sensing data LSdata supplied from the lead-out integrated circuit 170 during a second period T2 synchronized with the extinction control signal BLoff shown in FIG. The information stored in the light-off scan storage unit 184 is shown in FIG. 7B. In Fig. 7B, "B" indicates information on a portion where external light is blocked by a finger, and "C"

The difference value extracting unit 186 compares the light sensed data from the light scan storing unit 182 and the light extinguishing storage 184 on a one-to-one basis and extracts the difference value of the compared data, And generates position information XY. As shown in FIG. 7C, the extracted difference value information includes only the information A about the touch point by the finger.

On the other hand, in the touch position information detection circuit 180, two memories 182 and 184 may be integrated into one memory in order to cope with the reduction in the number of memories. Using the integrated memory, the touch position information detection circuit 180 stores the light sensing data LSdata supplied from the lead-out integrated circuit 170 during the first period T1, The light detection data LSdata supplied from the lead-out integrated circuit 170 during the second period T2 from the data LSdata is subtracted from the light detection data LSdata stored during the first period T1, Overwrite can be done.

The system 190 converts analog image data supplied from an external source, which is supplied through an interface circuit (not shown), into digital normal data RGB and supplies the digital normal data RGB to the timing controller 140. The system 190 extracts a composite image signal using the image data from the interface circuit, and outputs a synchronizing signal HV sync, a data enable signal (DE) and a dot clock (DCLK) to the timing controller 140.

In particular, the system 190 performs a processor process for touch recognition by applying the touch position information XY supplied from the touch position information detection circuit 180 to the touch recognition algorithm, including the touch algorithm processing unit 192 And reflects the execution result on the liquid crystal display panel 110 again. As described above, since the touch position information XY includes only the information about the touch point by the finger excluding the influence of external light, the touch recognition algorithm built in the touch algorithm processing unit 192 can be greatly simplified have. Since the touch position information XY includes only the information about the touch point by the finger excluding the influence of external light, the reliability of the touch recognition can be greatly improved.

As described above, the liquid crystal display device according to the present invention can simplify the algorithm of touch recognition and can greatly enhance the reliability of the touch recognition.

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. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

1 is an equivalent circuit diagram of an active matrix type liquid crystal display device.

2 is a diagram for explaining an operation of a touch sensor circuit;

FIG. 3 is a view showing a result of sensing a touched portion in a conventional liquid crystal display of a touch panel. FIG.

4 is a block diagram illustrating a liquid crystal display device according to an embodiment of the present invention.

5 is a timing diagram of first and second gate start pulses for implementing impulse driving through black data insertion.

6 is a detailed configuration diagram of the touch position information detection circuit shown in Fig.

FIG. 7A is a view showing information stored in the RGB scan storage unit of FIG. 6 or the lighting scan storage unit of FIG. 12;

FIG. 7B is a view showing information stored in the BD scan storage unit of FIG. 6 or the out-of-scan storage unit of FIG. 12;

FIG. 7C is a diagram showing information stored in the difference value extracting unit of FIG. 6 or FIG.

8 is an equivalent circuit diagram of the pixel shown in Fig.

9 is a block diagram showing a liquid crystal display device according to another embodiment of the present invention.

10 is a detailed configuration diagram of the backlight unit of FIG.

11 is a timing diagram of a plurality of control signals included in a backlight control signal;

Fig. 12 is a detailed configuration diagram of the touch position information detection circuit shown in Fig. 9; Fig.

Description of the Related Art

10, 110: liquid crystal display panel 20, 120:

30, 130: Gate drive circuit 40, 140: Timing controller

50, 150: driving voltage supply circuit 60, 160: backlight unit

70, 170: lead-out integrated circuit 80, 180: touch position information detection circuit

82: RGB scan storage unit 84: BD scan storage unit

86, 186: Difference value extracting unit 182:

184: Extinguishing scan storage unit 90, 190:

92, 192: touch algorithm processing section

Claims (9)

And a plurality of pixels including a pixel circuit and a touch sensor circuit that generates a photocurrent differently depending on whether the pixel circuit is touched at each intersection region of the gate lines and the data lines and displays normal data RGB for a first period, A liquid crystal display panel displaying black data (BD) during the second period; A backlight unit for irradiating light to the back surface of the liquid crystal display panel during the first period and the second period; A lead-out integrated circuit for converting the photocurrent from the touch sensor circuit into light sensing data; Wherein the photo sense data stored in the memory is stored in the memory after storing the photo sense data supplied from the lead-out integrated circuit during the first period and from the lead-out integrated circuit during the second period, A touch position information detection circuit for extracting a difference value between supplied light sensing data and generating touch position information excluding the influence of external light; And And a system for performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm; Wherein the memory stores only the photo sensed data supplied from the readout integrated circuit during the first period and does not store the photo sensed data supplied from the readout integrated circuit during the second period. . delete The method according to claim 1, Further comprising a timing controller for generating first and second gate start pulses respectively corresponding to the first and second periods; Wherein the first and second gate start pulses are sequentially generated by time-sharing one frame period. delete delete delete delete delete delete

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