KR20120000466A - Liquid crystal display device having touch sensor embedded therein, method for driving the same and method for fabricating the same - Google Patents

Abstract

PURPOSE: A liquid crystal display device with a touch sensor, a driving method thereof, and a manufacturing method thereof are provided for multi-touch detection by forming the touch sensor with a matrix structure. CONSTITUTION: A liquid crystal layer is formed between an upper substrate and a lower substrate. A pixel applies a horizontal electric field to the liquid crystal layer of a pixel area by a pixel electrode and a common electrode connected to a common line. A touch sensor(TS) is formed on the lower substrate between a plurality of pixels and senses a touch by forming capacitance and a touch object which touches the upper substrate. A sensor power line supplies driving power to a touch sensor. A readout line(ROL) outputs a sensing signal from the touch sensor.

Description

Liquid crystal display device with a built-in touch sensor, a driving method thereof, and a manufacturing method thereof {LIQUID CRYSTAL DISPLAY DEVICE HAVING TOUCH SENSOR EMBEDDED THEREIN, METHOD FOR DRIVING THE SAME AND METHOD FOR FABRICATING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device, a driving method thereof, and a method of manufacturing the same, which can be thin and lightweight by embedding a touch sensor.

Today, a touch screen capable of inputting information by touch on screens of various display devices is widely applied as an information input device of a computer system. Since the touch screen moves or selects display information by simply touching the screen with a finger or a stylus, it can be easily used by anyone of all ages.

The touch screen detects the touch and the touch position generated on the display device screen to output touch information, and the computer system analyzes the touch information to perform a command. As the display device, a flat panel display device such as a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED) display, or the like is mainly used.

Touch screen technologies include resistive, capacitive, infrared, ultrasonic, and electromagnetic methods, depending on the sensing principle. Among these, the resistive film type and the capacitive type are widely used in view of manufacturing cost.

The resistive touch screen detects a touch by detecting a voltage change generated by contact between upper and lower resistive films (transparent conductive films) by touch pressure. However, the resistive touch screen has a disadvantage in that the touch screen or the display device is easily damaged by the touch pressure, and the transmittance is low due to the light scattering effect of the air layer between the resistive films.

The capacitive touch screen, which can compensate for the disadvantage of the resistive film, senses a touch by detecting a change in capacitance caused by a small amount of charge moving to a touch point when a human body or a conductor such as a stylus touches the touch screen. Capacitive touch screens are attracting attention because they can use tempered glass, which is not only durable, high transmittance, excellent touch sensing capability, and multi-touch.

In general, the touch screen is manufactured in the form of a panel and attached to an upper portion of the display device to perform a touch input function. However, since the display device with a touch panel needs to be manufactured separately from the display device and attached to the display device, the manufacturing cost increases and the thickness and weight of the entire system increase, resulting in poor mobility or limited design. There is a problem that follows.

The present invention has been made to solve the above-mentioned problems of the prior art, the problem to be solved by the present invention is to provide a liquid crystal display device, a driving method and a manufacturing method that can be thin and lightweight by embedding a touch sensor.

Another object of the present invention is to provide a liquid crystal display, a driving method thereof, and a method of manufacturing the same, which simplify and incorporate a structure of a capacitive touch sensor and enable multi-touch sensing.

Another object of the present invention is to provide a liquid crystal display device, a driving method thereof, and a method of manufacturing the same, which can incorporate a touch sensor using the manufacturing process of the liquid crystal display device as it is.

In order to solve the above problems, the liquid crystal display device with a touch sensor according to an embodiment of the present invention includes a liquid crystal layer between the upper and lower substrates; In each pixel region formed on the lower substrate, a horizontal electric field is applied to the liquid crystal layer of the pixel region by a pixel electrode receiving a data signal through a thin film transistor connected to a gate line and a data line, and a common electrode connected to a common line. An applied pixel; A touch sensor formed between the plurality of pixels on the lower substrate and forming a capacitance with a touch object that touches the upper substrate to detect a touch; A sensor power line for supplying driving power to the touch sensor; And a readout line for outputting a sensing signal from the touch sensor.

The touch sensor may include a sensing electrode formed on the lower substrate to form the touch object and a sensing capacitor; A capacitor formed between the sensing electrode and the sensor power line; A sensor thin film transistor configured to form a current path between any one of the common line, the sensor power line, and the lead-out line in response to the control of the sensing electrode, and output the sensing signal when the sensing electrode senses the touch. Wow; And a diode connected between any one of the gate line and the sensor power line and the sensing electrode.

The diode is connected in a forward structure between any one of the gate line and the sensor power line and the sensing electrode.

The sensor thin film transistor outputs the sensing signal in response to a change in the voltage of the sensor electrode due to the series coupling of the sensing capacitor and the capacitor.

The sensing electrode and the sensing power line are formed of the same gate metal as the gate line.

The sensor thin film transistor includes a gate electrode connected to the sensing electrode, a source electrode connected to the readout line, and a drain electrode connected to any one of the common line and the sensor power supply line; The diode includes a gate electrode and a drain electrode connected to the sensing electrode, and a source electrode connected to any one of the gate line and the sensor power supply line.

The sensing electrode is independently formed in the touch sensor unit; The lead-out line is parallel with the data line and connected to a plurality of touch sensors arranged in a vertical direction; The sensor power line is parallel to the gate line and connected to a plurality of touch sensors arranged in a horizontal direction.

The sensor power line may be commonly connected with at least one other sensor power line.

The present invention includes a gate driver for driving the gate line; A data driver for driving the data line; A readout circuit configured to sense the touch using the sensing signal output from the readout line and to sense a position of the touch based on positions of the readout line and the sensor power line; A sensor power supply driving circuit for driving the sensor power supply line is further provided.

The readout circuit may be embedded in the data driver, or the sensor power supply driving circuit may be embedded in the gate driver.

The sensor power line is a sensor gate line for supplying a gate on voltage in a corresponding touch sensing period and a gate off voltage in the remaining period; The sensor power supply driving circuit is a sensor gate driver that scans the sensor gate line.

The sensor power line is a scanning power line for supplying a first common voltage in a corresponding touch sensing period and a second common voltage lower than the first common voltage in the remaining period, and the sensor power driving circuit scans the scanning power line. May be a scanning power supply circuit.

The gate driver and the data driver drive the gate line and the data line in a data write period; The sensing power circuit drives the sensing power line in the touch sensing period.

In the method of driving a liquid crystal display device having a touch sensor embedded therein, the data is stored in a plurality of pixels by driving a gate line and a data line in a data writing period, and applying a horizontal electric field according to the data to the liquid crystal layer of each pixel. Making a step; In the touch sensing period, driving the touch sensor formed between the plurality of pixels to detect the touch according to the capacitance formed between the touch object and the touch sensor to touch the upper substrate of the liquid crystal display.

The present invention divides and drives one frame into the data recording period and the touch sensing period, or divides one frame into units of a plurality of horizontal periods so that the data recording period and the touch sensing period alternate between the plurality of horizontal periods. do.

A method of manufacturing a liquid crystal display device having a touch sensor according to the present invention includes a gate metal including a gate thin film transistor, a sensor thin film transistor, and a gate electrode of a diode together with a gate line, a common line, a sensing electrode, and a sensing power line on a substrate. Forming a pattern; Forming a common electrode connected to the common line; Forming a gate insulating film on the substrate on which the gate metal pattern and the common electrode are formed; Forming semiconductor layers of each of the pixel thin film transistor, the sensor thin film transistor, and the diode on the gate insulating film; Forming a data metal pattern including a data line and a readout line on the gate insulating layer on which the semiconductor layer is formed, the data metal pattern including the pixel thin film transistor, the sensor thin film transistor, a source electrode and a drain electrode of each diode; Forming a passivation film covering the data metal pattern and forming a plurality of contact holes; Forming a pixel electrode on the passivation layer, the pixel electrode being connected to the drain electrode of the pixel thin film transistor through the contact hole and forming a horizontal electric field with the common electrode.

The liquid crystal display device in which the touch sensor of the present invention is embedded may be thin and light in weight by reducing the manufacturing cost by embedding the touch sensor in the thin film transistor substrate.

In addition, the liquid crystal display including the touch sensor of the present invention may detect a multi-touch since the touch sensor is formed in a matrix structure.

In addition, the liquid crystal display including the touch sensor according to the present invention may improve the aperture ratio by forming a touch sensor having a simple structure for sensing a touch in a capacitive manner for each pixel.

In addition, the liquid crystal display device in which the touch sensor of the present invention is embedded may form a touch sensor using the manufacturing process of the thin film transistor substrate as it is, thereby simplifying the manufacturing cost and thus reducing manufacturing cost.

In addition, since the liquid crystal display including the touch sensor of the present invention is driven by dividing the data recording period and the touch sensing period from each other, it is possible to prevent a deterioration in image quality due to interference of the touch sensor.

1 is a view schematically showing a vertical multi-sided structure of a liquid crystal display device with a touch sensor according to an embodiment of the present invention.
2 is a block diagram schematically illustrating a liquid crystal display device having a touch sensor according to an exemplary embodiment of the present invention.
3 is a frame configuration diagram of a liquid crystal display according to an exemplary embodiment of the present invention.
4 is an equivalent circuit diagram of some pixels of a liquid crystal display with a touch sensor according to an exemplary embodiment of the present invention.
FIG. 5 is a drive waveform diagram of the equivalent circuit shown in FIG. 4. FIG.
6 is a plan view of a thin film transistor substrate for an equivalent circuit of the liquid crystal display shown in FIG. 4;
FIG. 7 is a cross-sectional view of the thin film transistor substrate taken along the cutting lines of II ′ and II-II ′ in FIG. 6.
8 is an equivalent circuit diagram of some pixels of a liquid crystal display having a touch sensor according to another exemplary embodiment of the present invention.

1 is a view schematically illustrating a vertical cross-sectional structure of a liquid crystal display device with a touch sensor according to an embodiment of the present invention.

The liquid crystal display shown in FIG. 1 includes an upper substrate 50 and a lower substrate 60, and a liquid crystal layer 70 formed between upper and lower substrates 50 and 60.

A thin film transistor array including a plurality of pixel regions PX and a plurality of touch sensors TS is formed in the lower substrate 60. The touch sensor TS is formed between the plurality of pixel areas PX. That is, a plurality of pixel areas PX is positioned between two adjacent touch sensors TS. Each pixel area PX drives the liquid crystal layer 70 in an in plane switching (IPS) mode or a fringe field switching mode by applying a horizontal electric field to the liquid crystal layer 70. To this end, each pixel area PX receives a horizontal electric field in the liquid crystal layer 70 together with a pixel electrode receiving a data signal through a thin film transistor connected to a gate line and a data line, and receiving a common voltage. A common electrode is applied. Since a horizontal electric field is applied to the liquid crystal layer 70 in each pixel area PX of the lower substrate 60, an electrode for driving the liquid crystal layer 70 is not required for the upper substrate 50. The upper substrate 50 is provided with a color filter array including a black matrix defining the pixel region PX and red, green, and blue color filters corresponding to the pixel region PX, respectively. The liquid crystal display further includes upper and lower polarizers attached to the outer surfaces of the upper and lower substrates 50 and 60 and the optical axes are perpendicular to each other, and upper and lower alignment layers formed on the inner surface in contact with the liquid crystal to set the pretilt angle of the liquid crystal.

When the user touches the surface of the upper substrate 50 with a conductive touch object such as a human body or a stylus, the touch sensor TS of the lower object 60 between the upper substrate 50 and the liquid crystal layer 70 may be disposed between the touch object and the lower substrate 60. The capacitance, that is, the sensing capacitor Cf is formed. The touch sensor TS detects a change in capacitance caused by the formation of the sensing capacitor Cf and outputs a sensor signal indicating a touch.

2 is a block diagram schematically illustrating a liquid crystal display including a touch sensor according to an exemplary embodiment of the present invention.

2 includes a liquid crystal panel 10 having a plurality of pixels PX and a plurality of touch sensors TS, and a gate driving the plurality of gate lines GL of the liquid crystal panel 10. The driver 12, the data driver 14 driving the plurality of data lines DL of the liquid crystal panel 10, and the sensor gate driver 1 driving the sensor gate line SGL of the liquid crystal panel 10. And a readout circuit 18 for monitoring the output of the readout line ROL of the liquid crystal panel 10 to sense a touch. In FIG. 2, the readout circuit 18 may be embedded in the data driver 14, and the sensor gate driver 16 may also be embedded in the gate driver 12.

The liquid crystal panel 10 includes a plurality of pixels PX defined by crossing a plurality of gate lines GL and a plurality of data lines DL, and includes a touch sensor TS formed between the plurality of pixels PX. Is formed. The touch sensor TS is driven by the sensor gate line SGL, detects a touch in a capacitive manner, and outputs a sensing signal to the readout line ROL. The lead-out line ROL is formed in parallel with the data line DL between the plurality of data lines DL and connected to the plurality of touch sensors TS arranged in the vertical direction. The sensor gate line SGL is formed in parallel with the gate line GL between the plurality of gate lines GL, and is connected to the plurality of touch sensors TS arranged in the horizontal direction to supply driving power as a gate signal. . The plurality of sensor gate lines SGL may be independently driven for each line, or may be divided by a certain number of units and may be commonly driven with a certain number of sensor gate lines SGL. Since the touch sensors TS are arranged in a matrix form, multi-touch can be detected at the same time.

As shown in FIG. 3, the liquid crystal panel 10 is driven by dividing one frame 1F into a data writing period DWM for storing data in the pixel PX and a touch sensing period TSW for driving the touch sensor TS. . For example, as illustrated in FIG. 3A, one frame 1F includes a data write period DWM for storing a data signal in a plurality of pixels PX while scanning a plurality of gate lines GL in the first half and a second half. In FIG. 2, the touch sensing period TSW driving the touch sensor TS may be divided while scanning a plurality of sensor gate lines SGL. Meanwhile, as illustrated in FIG. 3B, one frame 1F may be divided into a plurality of horizontal periods (horizontal lines) so that the data recording period DWM and the touch sensing period TSW are alternated.

In the data writing period DWM, the gate driver 12 sequentially drives the plurality of gate lines GL in the data writing period DWM, and the data driver 14 stores data every time the gate line GL is driven. The signal is supplied to the plurality of data lines DL.

In the touch sensing period TSW, the sensor gate driver 16 sequentially drives the plurality of sensor gate lines SGL, and the readout circuit 18 reads a sensing signal from the touch sensor TS sensing the touch. Input through the outline (ROL) to detect the touch and touch location. The readout circuit 18 integrates the output current of the readout line ROL per unit time to sense a touch. The readout circuit 18 also detects the touch position (XY coordinate) based on the position information (X coordinate) of the lead out line ROL and the position information (Y coordinate) of the sensor gate line SGLi being driven. do. The readout circuit 18 may also detect the multi-touch generated simultaneously at different points through the touch sensor TS and the readout line ROL.

4 is a diagram illustrating an equivalent circuit of some pixels of a liquid crystal display including a touch sensor according to an exemplary embodiment of the present invention, and FIG. 5 is a diagram illustrating driving waveforms of the equivalent circuit illustrated in FIG. 4.

The liquid crystal display shown in FIG. 4 includes a plurality of pixels PX and a capacitive touch sensor TS formed between the plurality of pixels PX.

Each pixel PX includes a pixel thin film transistor Tpx formed in each pixel region defined by the crossing of the gate line GLi and the data line DL, and parallel between the pixel thin film transistor Tpx and the common line CLi. A liquid crystal capacitor Clc and a storage capacitor Cst which are connected are provided. The gate line GLi is formed in parallel with the common line CLi and the pixel region PX interposed therebetween. The liquid crystal capacitor Clc includes a pixel electrode connected to the thin film transistor Tpx, a common electrode connected to the common line CLi, and a liquid crystal layer to which a horizontal electric field is applied by the pixel electrode and the common electrode. The storage capacitor Cst is formed by overlapping a pixel electrode and a common electrode with an insulating layer interposed therebetween.

The pixel thin film transistor Tpx in response to the gate-on voltage Von of the gate signal from the corresponding gate line GLi in the data writing period DWM as shown in FIG. 5, the data signal DS from the data line DL. ) Is stored in the liquid crystal capacitor Clc and the storage capacitor Cst. The liquid crystal is driven according to the data signal stored in the liquid crystal capacitor Clc, and the storage capacitor Cst causes the liquid crystal capacitor Clc to stably maintain the data signal.

The touch sensor TS is formed in a space between the gate line GLi and the next storage line CLi + 1. The touch sensor TS includes a sensing electrode 20 for forming a touch object and a sensing capacitor Cf, a capacitor Cs connected between the sensing electrode 20 and the sensor gate line SGLj, and a sensing electrode ( A sensor thin film transistor Tsw connected between one end of the second end 20 and the readout line ROL and the storage line CLi + 1 and outputting a sensor signal, and the other end of the sensing electrode 20 and the sensor gate line SGLi. A diode Td serving as a resistance therebetween is provided. The readout line ROL is formed to be parallel to the data line DL, and outputs a touch signal supplied from the sensor thin film transistor Tsw to an external readout circuit. The sensing electrode 20 is independently formed for each touch sensor TS. The touch sensor TS is formed between a plurality of pixels PX (n, n is a natural number) in consideration of the size of the touch point. For example, when the line width of the touch point is about 4 mm, the touch sensor TS may be formed between about 50 pixels PX.

The gate electrode of the sensor thin film transistor Tsw is connected to the sensing electrode 20, the source electrode is connected to the readout line ROL, and the drain electrode is connected to the common line CLi + 1. The common voltage Vcom supplied to the common line CLi + 1 is used as driving power of the touch sensor. The source electrode and the drain electrode may be interchanged according to the current direction. The sensor thin film transistor Tsw is driven in the touch sensing period TSM of FIG. 5, and outputs a sensing signal to the readout line ROL in response to a variable voltage of the sensing electrode 20 according to the change in capacitance caused by the touch. do.

In the diode Td, the gate electrode and the drain electrode are connected to the sensing electrode 20, and the source electrode is connected to the sensor gate line SGLj. The diode Td is connected in a reverse direction between the sensing electrode 20 and the sensor gate line SGLj to stably maintain the gate-on voltage Von applied to the sensing electrode 20.

The sensor thin film transistor Tsw is turned on by the gate-on voltage Von of the sensing gate signal supplied from the corresponding sensor gate line SGLi via the diode Td in the touch sensing period TSM, and the remaining period of time. It is turned off to the gate off voltage Voff supplied to. When the touch object touches the surface of the liquid crystal display, a sensing capacitor Cf is formed between the touch object and the sensing electrode 20 to be connected in series with the capacitor Cs. In this case, when the sensor thin film transistor Tsw is turned on in the touch sensing period TSM, the gate-on voltage Von1 on the sensing electrode 20 is coupled in series on the sensing electrode 20 as shown in Equation 1 below. The capacitance varies with (Cc / (Cc + Cf)).

The sensor thin film transistor Tsw outputs a sensing signal by adjusting a current output to the readout line ROL in response to the variable gate-on voltage Von2. For example, the capacitance coupled by the touch (Cc / (Cc + Cf)) decreases, so that the gate-on voltage when the gate-on voltage Von2 at the touch on the sensing electrode 20 is measured as shown in FIG. 5. Since it decreases from Von1, the current output from the sensing thin film transistor Tsw to the readout line ROL is reduced. Accordingly, the readout circuit integrates the output current of the readout line ROL per unit time, and detects the touch by comparing the output current integrated value before the touch.

FIG. 6 is a plan view of a thin film transistor substrate for an equivalent circuit of the liquid crystal display shown in FIG. 4, and FIG. 7 is a cross-sectional view illustrating cut planes taken along lines II ′ and II-II ′ of FIG. 6.

 In the thin film transistor substrate shown in FIGS. 6 and 7, the common lines CLi and CLi, the gate lines GLi, the sensing electrodes 20, and the sensor gate lines SGLj are arranged in a gate metal pattern on the lower substrate 60. Is formed. The data line DL and the readout line ROL intersecting the gate metal pattern are formed in parallel with the data metal pattern on the gate insulating layer 62.

The pixel thin film transistor Tpx includes a gate electrode 22a protruding from the gate line GL, a semiconductor layer 24a overlapping the gate electrode 22a with the gate insulating layer 62 interposed therebetween, and a data line DL. Source electrode 26a protruding from the semiconductor layer 24a and overlapping with the semiconductor layer 24a, and facing the source electrode 26a at an overlapping portion with the semiconductor layer 24a and through the contact hole 40a of the passivation film 64. A drain electrode 28a connected to the pixel electrode 32 is provided. The semiconductor layer 24a includes an active layer forming a channel between the source electrode 26a and the drain electrode 28a, and the active layer and the source electrode 26a for ohmic contact with the source electrode 26a and the drain electrode 28a. And an ohmic contact layer formed at an overlapping portion of the drain electrode 28a.

In each pixel area defined by the intersection of the common line CLi and the gate line GLi and the data line DL, a transparent common electrode 30 connected to the common line CLi is formed. The transparent common electrode 30 is formed to partially overlap the common line CLi on the substrate 60 on which the common line CLi is formed before the gate insulating layer 62 is formed. The transparent pixel electrode 34 is formed to overlap the common electrode 30 on the passivation film 64, and includes a plurality of inclined slits 34 that are symmetrically formed up and down to form a horizontal electric field together with the common electrode 30. To drive the liquid crystal layer. The storage capacitor Cst is formed by overlapping the pixel electrode 34 and the common electrode 30.

The sensing electrode 20, the sensor gate line SGLj, the sensor thin film transistor Tsw, the diode Td, and the capacitor Cs are included in the space between the gate line GLi and the next common line CLi + 1. A touch sensor is formed.

The sensor thin film transistor Tsw includes a gate electrode 22b protruding from one end of the sensing electrode 20, a semiconductor layer 24b overlapping the gate electrode 22b with the gate insulating layer 62 interposed therebetween, and a lead. A source electrode 26b protruding from the outline ROL and overlapping the semiconductor layer 24b, and a drain facing the source electrode 26b at an overlapping portion of the semiconductor layer 24b and connected to the sensor gate line SGLi. An electrode 28b is provided. The drain electrode 28b overlaps the next common line CLi + 1 across the sensing gate line SGLi, and includes a contact hole 40b penetrating the passivation layer 64 and the gate insulating layer 62. It is formed on the passivation film 64 and is connected to the next common line CLi + 1 through the contact electrode 38a via the contact hole 40b.

The capacitor Cs has a structure in which the sensing electrode 20 and the capacitor electrode 36 are overlapped with the gate insulating layer 62 and the passivation layer 64. The capacitor electrode 36 overlaps the sensing electrode 20 and the sensor gate line SGLi, and passes through the contact hole 40e passing through the passivation layer 64 and the gate insulating layer 62. Connected with. The sensing electrode 20 forms a touch object and a sensing capacitor Cf.

The diode Td includes the gate electrode 22c protruding from the other end of the sensing electrode 20, the semiconductor layer 24c overlapping the gate electrode 22c with the gate insulating layer 62 interposed therebetween, and the sensor gate line. A source electrode 26c connected to the SGLi and overlapping the semiconductor layer 24c, and a drain electrode 28c facing the source electrode 26c and connected to the sensing electrode 20 at an overlapping portion with the semiconductor layer 24c. ). The source electrode 26c overlaps the sensing gate line SGLi and is formed on the contact hole 40c penetrating the passivation film 64 and the gate insulating film 62, and formed on the passivation film 64. It is connected to the sensor gate line SGLi through the contact electrode 38b via 40c. The drain electrode 28c overlaps the sensing electrode 20 and is formed on the contact hole 40d penetrating the passivation film 64 and the gate insulating film 62, and formed on the passivation film 64. It is connected to the sensing electrode 20 via the contact electrode 38c via).

The manufacturing method of the thin film transistor substrate shown in FIG. 6 and FIG. 7 is as follows.

On the substrate 60, a gate line GLi, a common line CLi and CLi + 1, a sensing electrode 20, a sensing gate line SGLi, a gate electrode 22a of a pixel thin film transistor Tpx, and a sensor A gate metal pattern including the gate electrode 22b of the thin film transistor Tsw and the gate electrode 22c of the diode Td is formed.

A transparent common electrode 30 connected to the common lines CLi and CLi + 1 is formed in each pixel area.

A gate insulating layer 62 is formed on the substrate 60 on which the common electrode 30 is formed. Then, the semiconductor layer 24a of the pixel thin film transistor Tpx and the sensor thin film transistor Tsw are formed on the gate insulating layer 62. A semiconductor pattern including the semiconductor layer 24b and the semiconductor layer 24c of the diode Td is formed.

The data line DL, the lead-out line ROL, the source electrode 26a and the drain electrode 28a of the pixel thin film transistor Tpx and the sensor thin film transistor Tsw are formed on the gate insulating layer 62 on which the semiconductor pattern is formed. A data metal pattern including a source electrode 26b and a drain electrode 28b, a source electrode 26c of the diode Td and a drain electrode 28c is formed.

The passivation film 64 is formed on the gate insulating film 62 on which the data metal pattern is formed, and the contact holes 40a and 40e penetrating the passivation film 64, the passivation film 64 and the gate insulating film. Contact holes 40b, 40c, and 40d penetrating through 62 are formed.

A transparent conductive pattern including the pixel electrode 32, the capacitor electrode 36, and the contact electrodes 38a, 38b, and 38c is formed on the passivation film 64.

As described above, the liquid crystal display according to the present invention may incorporate the touch sensor using the manufacturing process of the thin film transistor substrate as it is.

6 and 7 only form a horizontal electric field using the transparent common electrode 30 and the transparent pixel electrode 32 having a plurality of inclined slits 34 and insulated from the common electrode 30. For example, the pixel structure in which the common electrode and the pixel electrode are formed in the shape of a finger to form a horizontal electric field by the alternating structure of the finger portion of the common electrode and the finger portion of the pixel electrode may be applied. In this case, the finger-shaped common electrode or pixel electrode may be formed of an opaque metal.

8 is a diagram illustrating an equivalent circuit for some pixels of a liquid crystal display having a touch sensor according to another exemplary embodiment of the present invention.

In the equivalent circuit shown in FIG. 8, in contrast to the equivalent circuit shown in FIG. 4, the touch sensor TS includes a scanning power supply line SCLj instead of the sensor gate line SGLj of FIG. 4, and the sensor thin film transistor Tsw. The drain electrode of FIG. 4 is connected to the scanning power supply line SCLj instead of the next common line CLi + 1 of FIG. 4, and a resistor R such as the diode Td of FIG. 4 is connected to the gate line GLi and the sensing electrode. Only differences are connected between the points 20, and the rest of the configuration is the same, so the description of the overlapping components will be omitted. Since the configuration of the touch sensor TS is simpler than that of the equivalent circuit of FIG. 4, the equivalent circuit illustrated in FIG. 8 may improve the pixel aperture ratio.

The common line CLi supplies a DC common voltage Vcom, while the scanning power supply line SCLj supplies an AC common voltage that sequentially supplies a low common voltage VcomL and a high common voltage VcomH. For this purpose, instead of the sensor gate driver 16 illustrated in FIG. 2, a scanning power supply circuit (not shown) for scanning a plurality of scanning power lines SCL may be provided. The scanning power supply line SCLj supplies the high common voltage VcomH to the drain electrode of the sensor thin film transistor Tsw as a driving power during the touch sensing period TSM, and the scanning power line of the scanning power line different from the data writing period DWM. In the scanning period, a low common voltage VcomL such as a DC common voltage Vcom is supplied.

The resistor R is formed of a diode Td structure as shown in FIG. 4 and is forwardly connected between the gate line GLi and the sensing electrode 20, thereby applying a gate signal to the sensing electrode 20 from the gate line GLi. Keep it stable.

As described above, the liquid crystal display device in which the touch sensor of the present invention is embedded may be thin and light in weight by reducing the manufacturing cost by embedding the touch sensor in the thin film transistor substrate. In addition, since the touch sensor has a matrix structure, multi-touch can be detected. In addition, an aperture ratio may be improved by forming a touch sensor having a simple structure for sensing a touch in a capacitive manner for each pixel. In addition, since the touch sensor is formed using the manufacturing process of the thin film transistor substrate as it is, the manufacturing process may be further reduced, thereby further reducing manufacturing costs. In addition, since the data recording period and the touch sensing period are divided and driven, the image quality deterioration due to the interference of the touch sensor can be prevented.

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 gate driver
14: data driver 16: sensor gate driver
18: readout circuit 20: sensing electrode
22a, 22b, 22c: gate electrode 24a, 24b, 24c: semiconductor layer
26a, 26b, 26c: source electrode 28a, 28b, 28c: drain electrode
30: common electrode 32: pixel electrode
34: slanted slit 36: capacitor electrode
38a, 38b, 38c: contact electrode 40a, 40b, 40c, 40d, 40e: contact hole
50: upper substrate 60: lower substrate
62: gate insulating film 64: passivation film
70: liquid crystal layer GLi: gate line
DL: data line CLi, CLi + 1: common line
SGLj: Sensor Gate Line Tpx: Pixel Thin Film Transistor
Tsw: Sensor Thin Film Transistor Td: Diode
Cf: sensing capacitor Cs: capacitor

Claims (26)

A liquid crystal layer between the upper and lower substrates;
In each pixel region formed on the lower substrate, a horizontal electric field is applied to the liquid crystal layer of the pixel region by a pixel electrode receiving a data signal through a thin film transistor connected to a gate line and a data line, and a common electrode connected to a common line. An applied pixel;
A touch sensor formed between the plurality of pixels on the lower substrate and forming a capacitance with a touch object that touches the upper substrate to detect a touch;
A sensor power line for supplying driving power to the touch sensor;
And a readout line for outputting a sensing signal from the touch sensor. The method according to claim 1,
The touch sensor is
A sensing electrode formed on the lower substrate to form the touch object and a sensing capacitor;
A capacitor formed between the sensing electrode and the sensor power line;
A sensor thin film transistor configured to form a current path between any one of the common line, the sensor power line, and the lead-out line in response to the control of the sensing electrode, and output the sensing signal when the sensing electrode senses the touch. Wow;
And a diode connected between any one of the gate line and the sensor power line and the sensing electrode. The method according to claim 2,
And the diode is connected in a forward structure between any one of the gate line and the sensor power line and the sensing electrode. The method according to claim 2,
And the sensor thin film transistor outputs the sensing signal in response to a change in the voltage of the sensor electrode due to the series coupling of the sensing capacitor and the capacitor. The method according to claim 2,
And the sensing electrode and the sensing power line are formed of the same gate metal as the gate line. The method according to claim 2,
The sensor thin film transistor includes a gate electrode connected to the sensing electrode, a source electrode connected to the readout line, and a drain electrode connected to any one of the common line and the sensor power supply line;
And a diode including a gate electrode and a drain electrode connected to the sensing electrode, and a source electrode connected to any one of the gate line and the sensor power supply line. The method according to claim 2,
The sensing electrode is independently formed in the touch sensor unit;
The lead-out line is parallel with the data line and connected to a plurality of touch sensors arranged in a vertical direction;
And the sensor power line is parallel to the gate line and connected to a plurality of touch sensors arranged in a horizontal direction. The method according to claim 7,
And the sensor power line is commonly connected to at least one other sensor power line. The method according to claim 2,
A gate driver for driving the gate line;
A data driver for driving the data line;
A readout circuit configured to sense the touch using the sensing signal output from the readout line and to sense a position of the touch based on positions of the readout line and the sensor power line;
And a sensor power supply driving circuit for driving the sensor power supply line. The method according to claim 9,
And the readout circuit is embedded in the data driver or the sensor power supply driving circuit is embedded in the gate driver. The method according to claim 9,
The sensor power line is a sensor gate line for supplying a gate on voltage in a corresponding touch sensing period and a gate off voltage in the remaining period;
And the sensor power supply driving circuit is a sensor gate driver scanning the sensor gate line. The method according to claim 9,
The sensor power line is a scanning power line for supplying a first common voltage in a corresponding touch sensing period and a second common voltage lower than the first common voltage in the remaining period.
And the sensor power supply driving circuit is a scanning power supply circuit for scanning the scanning power supply line. The method according to claim 9,
The gate driver and the data driver drive the gate line and the data line in a data write period;
And the sensing power circuit drives the sensing power line during a touch sensing period. The method according to claim 13,
And dividing and driving one frame into the data recording period and the touch sensing period. The method according to claim 13,
And dividing one frame into units of a plurality of horizontal periods so that the data writing period and the touch sensing period are alternated for each of the plurality of horizontal periods. In the driving method of the liquid crystal display device with a built-in touch sensor,
Driving a gate line and a data line in a data writing period, storing data in a plurality of pixels and applying a horizontal electric field according to the data to the liquid crystal layer of each pixel;
In the touch sensing period, driving a touch sensor formed between the plurality of pixels to sense a touch according to a capacitance formed between the touch object touching the upper substrate of the liquid crystal display and the touch sensor. Method of driving a liquid crystal display device with a built-in touch sensor. The method according to claim 16,
The touch sensor is
A sensing electrode formed on the lower substrate of the liquid crystal display to form the touch object and a sensing capacitor;
A capacitor formed between the sensing electrode and a sensor power line;
In response to the control of the sensing electrode to form a current path between any one of the common line and the sensor power line and the lead-out line, when the sensing electrode detects the touch outputs the sensing signal to the lead-out line A sensor thin film transistor;
And a diode connected between any one of the gate line and the sensor power line and the sensing electrode. 18. The method of claim 17,
The sensor thin film transistor is configured to output the sensing signal in response to a change in the voltage of the sensor electrode due to the series coupling of the sensing capacitor and the capacitor. 18. The method of claim 17,
And the sensor power line is a sensor gate line for supplying a gate-on voltage in a corresponding touch sensing period and a gate-off voltage in a remaining period. 18. The method of claim 17,
The sensor power line may be a scanning power line for supplying a first common voltage in a corresponding touch sensing period and a second common voltage lower than the first common voltage in the remaining period. Driving method. The method according to claim 16,
And dividing and driving one frame into the data recording period and the touch sensing period. The method according to claim 16,
And dividing one frame into units of a plurality of horizontal periods so that the data writing period and the touch sensing period are alternated for each of the plurality of horizontal periods. Forming a gate metal pattern including a gate line, a common line, a sensing electrode, and a sensing power line on the substrate, the gate metal pattern including a gate electrode of each of a pixel thin film transistor, a sensor thin film transistor, and a diode;
Forming a common electrode connected to the common line;
Forming a gate insulating film on the substrate on which the gate metal pattern and the common electrode are formed;
Forming semiconductor layers of each of the pixel thin film transistor, the sensor thin film transistor, and the diode on the gate insulating film;
Forming a data metal pattern including a data line and a readout line on the gate insulating layer on which the semiconductor layer is formed, the data metal pattern including the pixel thin film transistor, the sensor thin film transistor, a source electrode and a drain electrode of each diode;
Forming a passivation film covering the data metal pattern and forming a plurality of contact holes;
Forming a pixel electrode connected to the drain electrode of the pixel thin film transistor through the contact hole on the passivation layer and forming a horizontal electric field with the common electrode; Method for manufacturing a display device. The method according to claim 23,
And forming a capacitor electrode connected to the sensor power line and forming the sensing electrode and the capacitor simultaneously with the pixel electrode. The method according to claim 23,
A source electrode is connected to the lead-out line, and a drain electrode is connected to any one of the common line and the sensor power supply line;
The gate electrode and the drain electrode of the diode are connected to the sensing electrode, the source electrode of the diode is connected to any one of the gate line and the sensor power supply line of the liquid crystal display device with a built-in touch sensor Way. The method according to claim 23,
The sensing electrode is formed independently for each touch sensor;
The lead-out line is parallel with the data line and connected to a plurality of touch sensors arranged in a vertical direction;
The sensor power supply line is parallel to the gate line and is connected to a plurality of touch sensors arranged in a horizontal direction.

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