KR102515949B1 - Touch screen device and method for driving the touch screen device - Google Patents

Abstract

The present invention relates to a touch screen device capable of improving a difference in touch performance occurring between touch electrodes disposed adjacent to a ground line and other touch electrodes excluding the touch electrodes, and a method of driving the same. A touch screen device according to an embodiment of the present invention includes any one of touch electrodes, a ground line disposed outside some of the touch electrodes, touch drive lines connected to each of the touch electrodes, and touch drive lines. A first multiplexer that selects and connects to a sensing line, a touch sensing circuit that accumulates the voltage applied to the sensing line and converts the accumulated voltage into touch raw data, which is digital data, and outputs it, and between the first multiplexer and the touch sensing circuit and a charge discharge circuit that lowers the voltage of the sensing line. The touch electrodes are divided into first touch electrodes disposed adjacent to the ground line and second touch electrodes excluding the first touch electrodes. The charge discharge circuit controls the charge discharge amount of the sensing line differently when the first touch electrodes are connected to the sensing line and when the second touch electrodes are connected to the sensing line.

Description

Touch screen device and its driving method {TOUCH SCREEN DEVICE AND METHOD FOR DRIVING THE TOUCH SCREEN DEVICE}

The present invention relates to a touch screen device and a method for driving the same.

Recently, various input devices such as a keyboard, a mouse, a track ball, a joystick, and a digitizer are being used to configure an interface between a user and home appliances or various information communication devices. Accordingly, demand for an input device that is convenient, simple, and capable of reducing malfunctions is increasing day by day. In response to such a demand, a touch screen device has been proposed in which a user inputs information by directly contacting a screen with a hand or a pen. A touch screen device is an input device that can be easily used by anyone of any age or gender by interactively and intuitively manipulating the buttons displayed on the display with a finger, so that many portable display devices such as smartphones, tablets, and PMPs applied to the device.

The touch screen device charges the capacitances of the touch electrodes by supplying touch driving voltages to the touch electrodes, senses the voltage charged in the capacitances of the touch electrodes, and outputs the sensed voltage as touch raw data. and a touch driver that calculates touch coordinates by analyzing touch raw data.

A ground line for preventing external static electricity from affecting the touch screen device may be disposed outside the left, bottom, and right sides of an active area of the touch screen device. The touch electrodes may be arranged in a matrix form in the active area.

The touch electrodes may be divided into first touch electrodes disposed adjacent to the ground line and second touch electrodes excluding the first touch electrodes. Since the first touch electrodes are disposed adjacent to the ground line, they may be affected by the ground line more than the second touch electrodes. As a result, touch raw data sensed by the first touch electrodes may have a higher value than touch raw data sensed by the second touch electrodes. Accordingly, touch performance may be lowered in the first touch electrodes than in the second touch electrodes. That is, a problem in which a difference in touch performance may occur between the first and second touch electrodes may occur.

Embodiments of the present invention relate to a touch screen device capable of improving a difference in touch performance occurring between touch electrodes disposed adjacent to a ground line and other touch electrodes excluding the touch electrodes, and a method of driving the same.

A touch screen device according to an embodiment of the present invention includes any one of touch electrodes, a ground line disposed outside some of the touch electrodes, touch drive lines connected to each of the touch electrodes, and touch drive lines. A first multiplexer that selects and connects to a sensing line, a touch sensing circuit that accumulates the voltage applied to the sensing line and converts the accumulated voltage into touch raw data, which is digital data, and outputs it, and between the first multiplexer and the touch sensing circuit and a charge discharge circuit that lowers the voltage of the sensing line. The touch electrodes are divided into first touch electrodes disposed adjacent to the ground line and second touch electrodes excluding the first touch electrodes. The charge discharge circuit controls the charge discharge amount of the sensing line differently when the first touch electrodes are connected to the sensing line and when the second touch electrodes are connected to the sensing line.

A method of driving a touch screen device according to an embodiment of the present invention includes touch electrodes, a ground line disposed outside some of the touch electrodes, touch driving lines connected to each of the touch electrodes, and among the touch driving lines. A first multiplexer that selects one and connects it to a sensing line, a touch sensing circuit that accumulates the voltage applied to the sensing line, converts the accumulated voltage into touch raw data, which is digital data, and outputs it, and the first multiplexer and touch sensing A touch screen device having a charge-discharge circuit connected between circuits and lowering a voltage of a sensing line, wherein the touch electrodes include first touch electrodes disposed adjacent to a ground line and second touch electrodes excluding the first touch electrodes. , and controls the charge discharge amount of the sensing line differently when the first touch electrodes are connected to the sensing line and when the second touch electrodes are connected to the sensing line.

In an embodiment of the present invention, the charge discharge amount of the voltage sensed by the first touch electrode may be controlled to be higher than the charge discharge amount of the voltage sensed by the second touch electrode. Therefore, in an embodiment of the present invention, when a touch does not occur, touch raw data sensed by the first touch electrode can be controlled to have a similar value to touch raw data sensed by the second touch electrode. Therefore, in the embodiment of the present invention, when a touch occurs on the first touch electrode, touch raw data sensed by the first touch electrode can be prevented from becoming higher than the maximum value recognizable by the touch coordinate calculator. As a result, it is possible to prevent a problem in which the user's touch is not recognized even though the user touches the first touch electrode.

1 is a block diagram showing in detail a touch screen device according to an embodiment of the present invention.
2 is an exemplary diagram showing a lower substrate of a display panel, source drive ICs, a timing control unit, a power supply unit, flexible films, a source circuit board, a flexible cable, and a control circuit board.
FIG. 3 is an exemplary view showing the pixels of FIG. 1 in detail.
4 is a waveform diagram illustrating a touch driving signal supplied to a touch driving line during one frame period.
5 is an exemplary diagram illustrating touch electrodes, touch driving lines, a ground line, and a touch driving unit.
6 shows touch row data sensed by first and second touch electrodes when touch does not occur, touch raw data sensed by first and second touch electrodes when touch occurs, and touch row data of an ROIC. It is an exemplary diagram showing the maximum data recognition value.
FIG. 7 is an exemplary view showing the touch driver of FIG. 5 in detail.
FIG. 8 is a flowchart illustrating in detail the control of the capacitance of the capacitor of the charge discharge circuit and the voltage input to the discharge voltage input terminal according to the selection of the first multiplexer of the touch driver of FIG. 7 .
9 is a circuit diagram showing in detail first and second discharge voltage output circuits of the source driver IC.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative, so the present invention is not limited to the details shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

When 'includes', 'has', 'consists', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, 'on top of', 'on top of', 'at the bottom of', 'next to', etc. Or, unless 'directly' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal precedence relationship is described in terms of 'after', 'following', 'next to', 'before', etc. It can also include non-continuous cases unless is used.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the first component mentioned below may also be the second component within the technical spirit of the present invention.

"X-axis direction", "Y-axis direction", and "Z-axis direction" should not be interpreted only as a geometric relationship in which the relationship between each other is made upright, and may be broader within the range in which the configuration of the present invention can function functionally. It can mean having a direction.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, "at least one of the first item, the second item, and the third item" means not only the first item, the second item, or the third item, respectively, but also two of the first item, the second item, and the third item. It may mean a combination of all items that can be presented from one or more.

Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or can be implemented together in a related relationship. may be

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing in detail a touch screen device according to an embodiment of the present invention. 2 is an exemplary diagram showing a lower substrate of a display panel, source drive ICs, a timing control unit, a power supply unit, flexible films, a source circuit board, a flexible cable, and a control circuit board. FIG. 3 is an exemplary view showing the pixels of FIG. 1 in detail. Hereinafter, a touch screen device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3 .

Although the touch screen device according to an embodiment of the present invention has been described mainly as being implemented in a self-capacitance (self capacitance) method, it should be noted that it is not limited thereto. That is, the touch screen device according to the embodiment of the present invention is not limited thereto. The screen device can be implemented with other capacitance methods such as a mutual capacitance method.

In addition, although the touch screen device according to the embodiment of the present invention has been described mainly in which the touch electrodes are implemented as an in-cell type included in the display panel 10, it should be noted that the present invention is not limited thereto. That is, the touch screen device according to an embodiment of the present invention may be implemented as an on-cell type in which touch electrodes are provided on the display panel 10 .

Furthermore, although the touch screen device according to the embodiment of the present invention has been mainly described as being a liquid crystal display, it should be noted that it is not limited thereto. That is, the touch screen device according to an embodiment of the present invention may be implemented as an organic light emitting display device, a plasma display device, or an electrophoresis display device.

A touch screen device according to an embodiment of the present invention, as shown in FIG. 1 , includes a display panel 10, a gate driver 20, a data driver 30, a timing controller 50, a touch driver 40, a touch coordinate calculator ( 60), and a power supply unit 70.

The display panel 10 includes a lower substrate 11, an upper substrate, and a liquid crystal layer interposed between the lower substrate and the upper substrate. The lower substrate 11 of the display panel 10 includes data lines (D1 to Dm, where m is a positive integer greater than or equal to 2), gate lines (G1 to Gn, where n is a positive integer greater than or equal to 2), and a touch driving line. (C1 to Cp, p is a positive integer of 2 or more) are formed. The data lines D1 to Dm and the touch driving lines C1 to Cp may be disposed parallel to each other. Also, the data lines D1 to Dm and the touch driving lines C1 to Cp may cross the gate lines G1 to Gn.

As shown in FIG. 1 , pixels P may be formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn. Each of the pixels P may be connected to a data line and a gate line. The pixels P may be formed in the active area AA displaying an image.

As shown in FIG. 3 , each of the pixels P may include a transistor T, a pixel electrode 11 , a liquid crystal cell LC, and a storage capacitor Cst. The transistor T is turned on by the gate signal of the kth gate line Gk (k is a positive integer satisfying 1≤k≤n), and the jth (j is a positive integer satisfying 1≤j≤m). An integer of) The data voltage of the data line Dj is supplied to the pixel electrode PE. The touch electrode TE receives a common voltage from one of the touch driving lines C1 to Cp (Cq). When a common voltage is supplied to the touch electrode TE, the touch electrode TE serves as a common electrode. Due to this, each of the pixels P drives the liquid crystal of the liquid crystal cell LC by an electric field generated by a potential difference between the data voltage supplied to the pixel electrode PE and the common voltage supplied to the touch electrode TE. A transmission amount of light incident from the backlight unit may be adjusted. As a result, the pixels P can display images. In addition, the storage capacitor Cst is provided between the pixel electrode PE and the touch electrode TE to maintain a constant voltage difference between the pixel electrode PE and the touch electrode TE.

A plurality of touch electrodes TE are formed on the display panel 10 as shown in FIG. 5 . Each of the touch electrodes TE may be formed to overlap with s (s is a positive integer greater than or equal to 2) number of pixels. For example, the size of the touch electrode TE may be set in consideration of a contact area of a finger and a contact area of a pen.

Each of the touch electrodes TE is connected to one of the touch driving lines C1 to Cp as shown in FIG. 5 . Each of the touch driving lines C1 to Cp connects each of the touch electrodes TE and the touch driver 40 . The touch electrodes TE receive the common voltage Vcom from the touch driver 40 during the display driving period DP through the touch driving lines C1 to Cp, and the touch driving voltages during the touch sensing period TP. can be supplied When the common voltage Vcom is supplied to the touch electrodes TE, the touch electrodes TE serve as a common electrode. The touch driving lines C1 to Cp may be disposed between two adjacent pixels.

A black matrix and a color filter may be formed on the upper substrate of the display panel 10 . However, when the display panel 10 is formed of a color filter on TFT (COT) structure, the black matrix and color filters may be formed on the lower substrate 11 of the display panel 10 .

A polarizer is attached to each of the upper substrate and the lower substrate 11 of the display panel 10, and an alignment layer for setting a pre-tilt angle of liquid crystal is formed. A column spacer is formed between the upper substrate and the lower substrate 11 of the display panel 10 to maintain a cell gap of the liquid crystal cell LC.

A backlight unit may be disposed under the rear surface of the lower substrate 11 of the display panel 10 . The backlight unit is implemented as an edge type or direct type backlight unit and irradiates light to the display panel 10 .

The gate driver 20 generates gate signals according to the gate control signal GCS input from the timing controller 50 . The gate driver 20 supplies gate signals to the gate lines G1 to Gn in a predetermined order during the display driving period DP. The predetermined order may be a sequential order. The gate driver 20 may not supply gate signals to the gate lines G1 to Gn during the touch sensing period TP. Alternatively, the gate driver 20 minimizes the parasitic capacitance between the touch electrodes TE and the gate lines G1 to Gn during the touch sensing period TP to improve touch performance through the gate lines G1 to Gn. ), the touch driving signal TDS may be supplied.

The gate driver 20 includes a plurality of transistors and may be directly formed in the non-display area NDA of the display panel 10 using a gate driver in panel (GIP) method. Alternatively, the gate driver 20 may be formed in the form of a driving chip and mounted on a flexible film (not shown) attached to the display panel 10 .

The data driver 30 receives digital video data DATA and a data control signal DCS from the timing controller 50 . The data driver 30 converts the digital video data DATA into analog data voltages according to the data control signal DCS. The data driver 30 supplies data voltages to the data lines D1 to Dm during the display driving period DP. The data driver 30 may not supply data voltages to the data lines D1 to Dm during the touch sensing period TP. Alternatively, the data driver 30 minimizes parasitic capacitance between the touch electrodes TE and the data lines D1 to Dm during the touch sensing period TP to improve touch performance of the data lines D1 to Dm. ), the touch driving signal TDS may be supplied.

The touch driver 40 receives the mode signal MODE from the timing controller 50, the touch control signal TCS from the touch coordinate calculation unit 60, and the common voltage Vcom from the power supply unit 70. is input.

The touch driver 40 may operate by dividing one frame period into a display driving period DP and a touch sensing period TP according to the mode signal MODE as shown in FIG. 4 . When the mode signal MODE of the first logic level voltage is input, the touch driver 40 determines the display driving period DP and supplies the common voltage Vcom to the touch driving lines C1 to Cp. When the mode signal MODE of the second logic level voltage is input, the touch driver 40 determines the touch sensing period TP to generate the touch driving signal TDS according to the touch control signal TCS, and generates the touch driving signal TDS in a predetermined order. It can be supplied to the touch driving lines C1 to Cp as follows. For example, the touch driver 40 may sequentially supply the touch driving signal TDS during the touch sensing period TP as shown in FIG. 4 .

As shown in FIG. 4 , the touch driving signal TDS may include a plurality of pulses. The plurality of pulses may swing between a high level voltage HV higher than the common voltage Vcom and a low level voltage LV lower than the common voltage Vcom. The touch driver 40 senses voltages of the touch electrodes TE, converts the sensed voltages into touch raw data TRD, and outputs the converted touch raw data TRD to the touch coordinate calculator 60 . A detailed description of the touch driver 40 will be described later with reference to FIG. 6 .

The data driver 30 and the touch driver 40 may be included in a source drive integrated circuit (IC) 80 . Each of the source drive ICs 21 may be mounted on each of the flexible films 22 . Each of the flexible films 22 may be a tape carrier package or a chip on film. Each of the flexible films 22 may be bent or bent. Each of the flexible films 22 may be attached to the lower substrate 11 and the source circuit board 60 . Each of the flexible films 22 may be attached on the lower substrate 11 by a tape automated bonding (TAB) method using an anisotropic conductive film, and thereby the source drive ICs 21 are connected to the data line. It can be connected to (D1 ~ Dm). The source circuit board 60 may be connected to the control circuit board 70 by a cable 80 . The source circuit board 60 may be a printed circuit board or a flexible printed circuit board.

The timing controller 50 receives digital video data DATA and timing signals TS from an external host system. The timing signals TS may include a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a dot clock, and the like. The vertical synchronization signal is a signal defining one frame period. The horizontal synchronization signal is a signal defining one horizontal period for supplying data voltages to pixels of one horizontal line of the display panel 10 . Pixels of one horizontal line can be connected to the same gate line. The data enable signal is a signal defining a period during which valid digital video data is supplied. The dot clock is a clock signal that is repeated at a predetermined cycle.

As shown in FIG. 4 , the timing controller 50 divides 1 frame period into a display driving period (DP) and a touch sensing period (TP), and the gate driving unit 20 operates the gate during the display driving period (DP). Gate signals are supplied to the lines G1 to Gn, and the data driver 30 controls to supply data voltages to the data lines D1 to Dm. Although FIG. 4 illustrates that one frame period is divided into one display driving period (DP) and one touch sensing period (TP), it should be noted that it is not limited thereto. That is, since 1 frame period only needs to include at least one display driving period (DP) and a touch sensing period (TP), it includes a plurality of display driving periods (DP) or touch sensing periods (TP). can do.

The timing controller 50 generates a gate control signal GCS for controlling the operation timing of the gate driver 20 and a data control signal DCS for controlling the operation timing of the data driver 30 based on the timing signals. generate The timing controller 50 outputs the gate control signal GCS to the gate driver 20 and outputs the digital video data DATA and the data timing control signal DCS to the data driver 30 .

The timing controller 50 may generate a mode signal MODE to distinguish between the display driving period DP and the touch sensing period TP. The timing controller 50 may output the mode signal MODE to the touch driver 40 .

The touch coordinate calculator 60 receives touch row data TRD from the touch driver 40 . The touch coordinate calculation unit 60 determines that a user's touch has occurred when the touch raw data TRD equal to or greater than the first reference value is input, and calculates the coordinates of the touch electrodes TE of the touch raw data TRD equal to or greater than the first reference value. It is calculated by touch coordinates. The touch coordinate calculator 60 outputs touch coordinate data CD including touch coordinate information to an external host system. The touch coordinate calculator 60 may be included in the timing controller 50 .

The host system (not shown) converts the digital video data DATA into a format suitable for display on the display panel 10 and transmits it to the timing controller 50 . The host system (not shown) receives the touch coordinate data CD from the touch coordinate calculator 60 . A host system (not shown) executes an application program or an application program of an icon existing at touch coordinates according to the touch coordinate data (CD), and timing the digital video data (DATA) and timing signals (TS) according to the execution program. It is transmitted to the control unit 50.

The host system (not shown) is a central processing unit of any one of a navigation system, a set-top box, a DVD player, a Blu-ray player, a personal computer (PC), a laptop computer, a home theater system, a broadcasting receiver, a smartphone, a tablet, and a mobile terminal ( CPU), a host processor, an application processor, or a graphics processing unit (GPU).

As shown in FIG. 1 , the power supply unit 70 may include a common voltage supply circuit that supplies the common voltage Vcom to the touch driver 40 . The common voltage supply circuit may receive feedback of the common voltage of the display panel 10 and output a common voltage Vcom obtained by compensating for a ripple of the received common voltage to the touch driver 40 .

In addition, the power supply 70 supplies the first level voltage V1 of the touch driver 50 to the touch driver 40, or a second level voltage lower than the first level voltage V1 and the first level voltage V1. The level voltage V2 may be supplied to the touch driver 40 . A detailed description of the first and second level voltages V1 and V2 will be described later with reference to FIG. 7 .

In addition, the power supply 70 may supply gate driving voltages such as a gate high voltage and a gate low voltage to the gate driver 20 and supply gamma reference voltages and a VDD voltage to the data driver 30 . Also, the power supply unit 70 may supply predetermined driving voltages to the timing controller 50 .

The timing controller 50 , the touch coordinate calculation unit 60 , and the power supply unit 70 may be mounted on the control circuit board 70 . The control circuit board 70 may be connected to the source circuit board 60 by a cable 80 . The control circuit board 70 may be a printed circuit board or a flexible printed circuit board. Cable 80 may be a flexible cable.

5 is an exemplary diagram illustrating touch electrodes, touch driving lines, a ground line, and a touch driving unit. 5, for convenience of description, the lower substrate 11, the touch electrodes TE1 and TE2, the touch driving lines C1 to Cr, where r is a positive integer satisfying 2≤r≤p, and the ground line ( GND), and only the touch driver 50 are shown.

Referring to FIG. 5 , the touch electrodes TE1 and TE2 are disposed in the active area AA. A ground line GND is disposed outside some of the touch electrodes TE1 and TE2 . For example, as shown in FIG. 5 , the ground line GND may be disposed outside the left, right, and lower sides of the active area AA.

Each of the touch electrodes TE1 and TE2 is connected to one of the touch driving lines C1 to Cp. Each of the touch driving lines C1 to Cp connects one of the touch electrodes TE1 and TE2 to the touch driver 40 . That is, each of the touch electrodes TE1 and TE2 is connected to one of the touch driving lines C1 to Cp, and thus, in an embodiment of the present invention, touch sensing can be performed in a self-capacitance method.

To protect the display panel 10 from external static electricity, a ground line GND may be disposed outside some of the touch electrodes TE1 and TE2 . The touch electrodes TE1 and TE2 may be divided into first touch electrodes TE1 disposed adjacent to the ground line GND and second touch electrodes TE2 excluding the first touch electrodes TE1. .

Since the first touch electrodes TE1 are disposed adjacent to the ground line GND, they may be affected by the ground line GND more than the second touch electrodes TE2 . For example, a fringe capacitance may be formed between the first touch electrode TE1 and the ground line GND. In this case, due to the fringe capacitance, even if no touch occurs as shown in FIG. 6 , the touch raw data TRD_NT sensed by the first touch electrode TE1 is the touch raw data sensed by the second touch electrode TE2 ( TRD_NT). For this reason, when a touch occurs on the first touch electrode TE1, the touch raw data NRD_TG sensed by the first touch electrode TE1 is higher than the maximum value MAX recognizable by the touch coordinate calculator 60. can rise Accordingly, the touch coordinate calculator 60 may recognize the touch raw data NRD_TG sensed by the first touch electrode TE1 as the maximum value MAX. In this case, when a flattening process is performed to facilitate operation of the touch raw data, the size of the touch raw data NRD_TG sensed by the first touch electrode TE1 becomes smaller than the originally sensed size. As a result, even though the user touches the first touch electrode TE1, a problem of not recognizing the user's touch may occur. That is, touch performance may be lowered in the first touch electrodes than in the second touch electrodes.

In order to solve the above problem, an embodiment of the present invention controls the charge discharge amount of the voltage sensed by the first touch electrode TE1 to be higher than the charge discharge amount of the voltage sensed by the second touch electrode TE2. . Therefore, in the embodiment of the present invention, when no touch occurs, the touch raw data TRD_NT sensed by the first touch electrode TE1 corresponds to the touch raw data TRD_NT sensed by the second touch electrode TE2 It can be controlled to have a value similar to Therefore, in the embodiment of the present invention, when a touch occurs on the first touch electrode TE1, the touch raw data NRD_TG sensed by the first touch electrode TE1 is the maximum value recognizable by the touch coordinate calculator 60. It can be prevented from being higher than the value (MAX). As a result, even though the user touches the first touch electrode TE1, the problem of not recognizing the user's touch can be prevented.

Hereinafter, a touch driver 40 according to an embodiment of the present invention and a driving method for solving the above problem will be described in detail with reference to FIGS. 7 and 8 .

FIG. 7 is an exemplary view showing the touch driver of FIG. 4 in detail. Referring to FIG. 7 , the touch driver 40 includes a first multiplexer 41 , a charge/discharge circuit 42 , and a touch sensing circuit 43 .

The first multiplexer 41 is connected between the touch driving lines C1 to Cr and the sensing line SL. The first multiplexer 41 selects one of the touch driving lines C1 to Cr according to the first multiplexer control signal MCS and connects it to the sensing line SL. The first multiplexer control signal MCS may be input from the timing controller 40 .

A charge removing circuit or charge discharging circuit 42 is connected to the sensing line SL. The charge discharge circuit 42 discharges the charge of the sensing line SL. The charge discharge circuit 42 may include a discharge voltage input terminal CVT to which a discharge voltage for charge discharge is applied and a capacitor Ccr between the discharge voltage input terminal CVT and the sensing line SL.

The touch sensing circuit 43 accumulates and senses the voltage of the sensing line SL, converts the sensed voltage into touch row data TRD, which is digital data, and outputs it. The touch sensing circuit 43 includes a touch voltage sensing circuit SU and an analog digital converter (ADC).

The touch voltage sensing circuit 43 senses the voltage of the sensing line SL. The touch voltage sensing unit SU may include an operational amplifier OA and a feedback capacitor Cfb. The operational amplifier OA includes a first input terminal IN1, a second input terminal IN2, and an output terminal o. The first input terminal IN1 of the operational amplifier OA is connected to the sensing line SL, the second input terminal IN2 is connected to the reference voltage line VREFL to which the reference voltage is supplied, and the output terminal o ) may be connected to the storage capacitor Cs. The storage capacitor Cs is connected between the output terminal o and the ground voltage source to store the output voltage Vout1 of the output terminal o. The feedback capacitor Cfb may be connected between the first input terminal IN1 and the output terminal o of the operational amplifier OA.

In this case, the output voltage Vout1 of the operational amplifier OA may be defined as in Equation 1.

In Equation 1, “Vout1” is the output voltage of the touch voltage sensing unit SU, “Cf” is the capacitance of the touch electrode TE, “Cp1” is the parasitic capacitance of the touch electrode TE, and “Cfb” is the capacitance of the touch electrode TE. The capacity of the feedback capacitor, "Vt", indicates the voltage of the sensing line SL.

The analog-to-digital converter ADC may be connected to the storage capacitor Cs through a switch SW. The switch (SW) is switched by the switch signal (SCS) to control the connection between the analog-to-digital converter (ADC) and the storage capacitor (Cs). Since the analog-to-digital conversion unit (ADC) is connected to the storage capacitor (Cs) during the turn-on period of the switch (SW), the output voltage (Vout) stored in the storage capacitor (Cs) is converted into touch raw data (TRD), which is digital data. convert The analog-to-digital converter ADC outputs the touch row data TRD to the touch coordinate calculator 60 .

FIG. 8 is a flowchart illustrating in detail the control of the capacitance of the capacitor of the charge discharge circuit and the voltage input to the discharge voltage input terminal according to the selection of the first multiplexer of the touch driver of FIG. 7 .

Referring to FIG. 8 , the charge discharge amount of the sensing line SL is controlled according to whether the touch driving line connected to the first touch electrode TE1 by the first multiplexer 41 is connected to the sensing line SL. . (S101 in FIG. 8)

When the touch driving line connected to the first touch electrode TE1 by the first multiplexer 41 is connected to the sensing line SL, the charge discharge amount of the sensing line SL is increased. The charge discharge amount (Q) is proportional to the capacity (C) and voltage (V) of the capacitor (Ccr) as shown in Equation 2.

Referring to Equation 2, when the capacity (C) of the capacitor (Ccr) is increased or the discharge voltage supplied to the discharge voltage input terminal (CVT) is increased, the charge discharge amount (Q) can be increased.

Therefore, when the touch driving line connected to the first touch electrode TE1 by the first multiplexer 41 is connected to the sensing line SL, the capacitance C of the capacitor Ccr is set to the first capacitance, or , the discharge voltage supplied to the discharge voltage input terminal CVT may be set to the first level voltage. Alternatively, in order to further increase the charge discharge amount Q, the capacitance C of the capacitor Ccr may be set to the first capacitance and the discharge voltage supplied to the discharge voltage input terminal CVT may be set to the first level voltage. there is.

In contrast, when the touch driving line connected to the second touch electrode TE2 by the first multiplexer 41 is connected to the sensing line SL, the capacitance C of the capacitor Ccr is lower than the first capacitance. The second capacity may be set, and the discharge voltage supplied to the discharge voltage input terminal CVT may be set to a second level voltage lower than the first level voltage. Alternatively, the capacitance C of the capacitor Ccr may be set to the second capacitance and the discharge voltage supplied to the discharge voltage input terminal CVT may be set to the second level voltage. (S102, S103 in FIG. 8)

As described above, in the embodiment of the present invention, the charge discharge amount of the voltage sensed by the first touch electrode TE1 can be controlled to be higher than the charge discharge amount of the voltage sensed by the second touch electrode TE2. there is. Therefore, in the embodiment of the present invention, when no touch occurs, the touch raw data TRD_NT sensed by the first touch electrode TE1 corresponds to the touch raw data TRD_NT sensed by the second touch electrode TE2 It can be controlled to have a value similar to Therefore, in the embodiment of the present invention, when a touch occurs on the first touch electrode TE1, the touch raw data NRD_TG sensed by the first touch electrode TE1 is the maximum value recognizable by the touch coordinate calculator 60. It can be prevented from being higher than the value (MAX). As a result, even though the user touches the first touch electrode TE1, the problem of not recognizing the user's touch can be prevented.

In addition, the touch driver 40 further includes a discharge voltage output unit 44 for outputting the discharge voltage input to the discharge voltage input terminal CVT as a first level voltage or a second level voltage as shown in FIGS. 9A and 9B. can include

The discharge voltage output unit 44 may include a resistance string circuit (R-String, RS) and a second multiplexer (MUX) as shown in FIG. 9A, and may include a first level voltage (V1) and a second multiplexer control signal (MCS2). ) can be entered.

The resistance column circuit RS may divide the first level voltage V1 to generate the second level voltage V2. The resistance column circuit RS may include a plurality of resistors R1 and R2 connected between the first level voltage input terminal VIT to which the first level voltage is input and the ground GND.

The second multiplexer MUX outputs a first level voltage V1 input through the first level voltage input terminal VIT according to the second multiplexer control signal MCS2 and a plurality of resistors R1 and R2 to generate voltage. Select one of the second level voltages V2 generated through distribution and output to the discharge voltage input terminal CVT. That is, when receiving only the first level voltage V1, the discharge voltage output unit 44 may directly generate the second level voltage using the resistance column circuit RS.

For example, when the first touch electrode TE1 is connected to the sensing line SL, the second multiplexer control signal MCS2 applies a first logic level voltage to the second touch electrode TE2 connected to the sensing line SL. When connected, it may have a second logic level voltage. The second multiplexer MUX may output the first level voltage V1 to the discharge voltage input terminal CVT when the second multiplexer control signal MCS2 having the first logic level voltage is input. The second multiplexer MUX may output the second level voltage V2 to the discharge voltage input terminal CVT when the second multiplexer control signal MCS2 having the second logic level voltage is input.

Alternatively, the discharge voltage output unit 44 supplies the first and second level voltages V1 and V2 respectively to the voltage supply unit 70 through the first and second voltage input terminals VIT1 and VIT2, respectively, as shown in FIG. 9B. ), it may include only the second multiplexer MUX2.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and may be variously modified and implemented without departing from the technical spirit of the present invention. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be construed according to the claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

10: display panel 20: gate driver
30: data driving unit 40: touch driving unit
41: first multiplexer 42: charge discharge circuit
43: touch sensing circuit 44: discharge voltage output unit
50: timing control unit 60: touch coordinate calculation unit
70: power supply unit 80: source drive IC

Claims (10)

touch electrodes;
a ground line disposed outside some of the touch electrodes;
touch driving lines respectively connected to each of the touch electrodes;
a first multiplexer selecting one of the touch driving lines and connecting it to a sensing line;
a touch sensing circuit for accumulating voltages applied to the sensing lines, converting the accumulated voltages into digital touch row data, and outputting the converted touch raw data; and
a charge-discharge circuit connected between the first multiplexer and the touch sensing circuit and lowering a voltage of the sensing line;
The touch electrodes are divided into first touch electrodes disposed adjacent to the ground line and second touch electrodes excluding the first touch electrodes, and the first touch electrodes adjacent to the ground line are the second touch electrodes. has a larger parasitic capacitance than
The charge discharge circuit determines the first charge discharge amount of the sensing line when the first touch electrodes are connected to the sensing line, and the second charge discharge amount of the sensing line when the second touch electrodes are connected to the sensing line. A touchscreen device that controls greater than full volume. According to claim 1,
The charge discharge circuit,
a discharge voltage input terminal to which discharge voltage is input; and
A touch screen device comprising a capacitor connected between the discharge voltage input terminal and the sensing line. According to claim 2,
The capacitor has a first capacitance when the first touch electrodes are connected to the sensing line, and has a second capacitance lower than the first capacitance when the second touch electrodes are connected to the sensing line. According to claim 2,
The discharge voltage is supplied as a first level voltage when the first touch electrodes are connected to the sensing line, and as a second level voltage lower than the first level voltage when the second touch electrodes are connected to the sensing line. Supplied touch screen device. According to claim 4,
and a discharge voltage output unit including a second multiplexer for selecting one of the first level voltage and the second level voltage and outputting the selected one to the discharge voltage input terminal. According to claim 5,
The touch screen device of claim 1 , wherein the discharge voltage output unit further includes a resistance column configured to generate the second level voltage by dividing the first level voltage. According to claim 5 or 6,
data lines parallel to the touch driving lines; and
Further comprising source drive ICs supplying data voltages to the data lines;
The touch sensing circuit, the first multiplexer, the charge-discharge circuit, and the discharge voltage output unit are embedded in the source driver IC. A first method for selecting and connecting one of touch electrodes, a ground line disposed outside some of the touch electrodes, touch driving lines connected to each of the touch electrodes, and the touch driving lines to a sensing line. a multiplexer, a touch sensing circuit that accumulates voltages applied to the sensing lines, converts the accumulated voltages into touch row data, which is digital data, and outputs the touch raw data, and is connected between the first multiplexer and the touch sensing circuit, and In the touch screen device having a charge discharge circuit for lowering the voltage,
The touch electrodes are divided into first touch electrodes disposed adjacent to the ground line and second touch electrodes excluding the first touch electrodes, and the first touch electrodes adjacent to the ground line are the second touch electrodes. has a larger parasitic capacitance than
Controlling a first charge discharge amount of the sensing line when the first touch electrodes are connected to the sensing line to be greater than a second charge discharge amount of the sensing line when the second touch electrodes are connected to the sensing line A method of driving a touch screen device. According to claim 8,
supplying a discharge voltage supplied to the charge discharge circuit as a first level voltage when the first touch electrodes are connected to the sensing line; and
and supplying the discharge voltage as a second level voltage lower than the first level voltage when the second touch electrodes are connected to the sensing line. According to claim 8,
setting a discharge capacitor of the charge-discharge circuit to a first capacity when the first touch electrodes are connected to the sensing line; and
and setting the discharge capacitor to a second capacitance lower than the first capacitance when the second touch electrodes are connected to the sensing line.

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