KR102504529B1 - Touch Screen Device and Method for Driving The Same - Google Patents

Abstract

In the present invention, in order to prevent the output voltage of the touch voltage sensing unit from being saturated, during a unit touch sensing period in which a plurality of sub-sensing periods and a plurality of sub-reset periods are alternately configured, the touch voltage sensing unit detects blackout of the touch electrode for each sub-sensing period. The output voltage is calculated by sensing the voltage charged in the capacitance and the parasitic capacitance, the output voltage is reset in each sub-reset period, and the analog-to-digital conversion unit converts the output voltage of the touch voltage sensing unit calculated in each sub-sensing period into digital data. touch row data, and a digital integrator calculates touch row data of a unit touch sensing period by accumulating sub-touch row data calculated during a unit touch sensing period.

Description

Touch screen device and method for driving the same {Touch Screen Device and Method for Driving The Same}

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

Various input devices such as a keyboard, a mouse, a track ball, a joystick, a digitizer, and the like are used to configure an interface between a user and various electronic 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 in which a user inputs information by directly contacting a screen with a hand or a pen has been proposed. A touch screen device can input information simply by touching a button displayed on a display unit with a finger, so that anyone of any age or gender can easily use the touch screen 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.

When the touch screen device is implemented as an in-cell type provided in a display panel for displaying images, the touch electrodes include pixel electrodes of pixels constituting the display panel 10 and a plurality of pixels connected to the pixels. It may be formed adjacent to the driving lines. Parasitic capacitance is formed between the touch electrodes and the pixel electrodes/drive lines, and capacitance is formed between the touch electrodes and a person's finger or pen. That is, parasitic capacitance and capacitance are formed in the touch electrode where the touch occurs, but only parasitic capacitance is formed in the touch electrode where the touch does not occur.

At this time, as shown in FIG. 1 , the touch voltage sensing unit included in the touch driver uses a difference (gap) between the output voltage of the touch electrode where the touch occurs and the output voltage of the touch electrode where the touch does not occur. It determines whether it has been touched.

However, the permissible range for the output voltage of the touch voltage sensing unit is predetermined. Since not only capacitance but also parasitic capacitance are continuously accumulated and increased in the process of calculating the output voltage of the touch voltage sensing unit, the output voltage of the touch voltage sensing unit is Saturation may occur outside the defined allowable range.

As such, when the output voltage of the touch voltage sensing unit is saturated, there is a problem in that SNR characteristics are deteriorated and accurate touch determination cannot be made.

The present invention is to solve the above problems, and provides a touch screen device and a driving method capable of preventing the output voltage of a touch voltage sensing unit from being saturated.

In order to achieve the above object, a touch screen device according to an aspect of the present invention provides a unit touch sensing period in which a plurality of sub-sensing periods and a plurality of sub-reset periods are alternately configured, during each sub-sensing period, blackout of the touch electrode A touch voltage sensing unit that senses the voltage charged in capacitance and parasitic capacitance to calculate an output voltage and resets the output voltage for each sub-reset period, and converts the output voltage of the touch voltage sensing unit calculated for each sub-sensing period into digital data an analog-to-digital conversion unit that converts in sub-touch raw data into sub-touch raw data, and a digital integrator that calculates touch-row data of the unit touch sensing period by accumulating the sub-touch raw data calculated during the unit touch sensing period. do.

To achieve the above object, a method of driving a touch screen device according to another aspect of the present invention includes charging capacitance and parasitic capacitance of touch electrodes with a touch driving voltage, a plurality of sub-sensing periods and a plurality of sub-reset periods. During the alternately configured unit touch sensing period, calculating an output voltage by sensing the voltage charged in the capacitance and parasitic capacitance of the touch electrode in each sub-sensing period, and resetting the output voltage in each sub-reset period converting the output voltage calculated for each sub-sensing period into sub-touch raw data that is digital data; and accumulating sub-touch raw data generated during the unit touch sensing period to obtain a It is characterized in that it includes the step of calculating raw data.

According to the present invention, by dividing and integrating the sensing data for one touch electrode multiple times during the touch sensing period, saturation of the output voltage of the touch voltage sensing unit can be prevented, thereby preventing a decrease in SNR and improving the accuracy of touch sensing. There is an effect that can be done.

1 is a diagram showing that the output voltage of a general touch voltage sensing unit is saturated.
2 is a block diagram showing in detail a touch screen device according to an embodiment of the present invention.
FIG. 3 is an exemplary diagram illustrating pixels, touch electrodes, touch driving lines, and a touch driver of the display panel of FIG. 2 .
FIG. 4 is an exemplary diagram showing the pixels of FIG. 3 in detail.
5 is a waveform diagram showing signals supplied to touch driving lines during one frame period.
6 is a block diagram showing the configuration of a touch driver according to an embodiment of the present invention.
FIG. 7 is a circuit diagram showing the configuration of the touch voltage sensing unit shown in FIG. 6 .
FIG. 8 is a diagram showing an operation timing diagram of the touch voltage sensing unit shown in FIG. 7 .
9 is a diagram showing a comparison between touch raw data according to the present invention and touch raw data according to the prior art.
10 is a flowchart showing a method of driving a touch screen device according to an embodiment of the present invention.

The meaning of terms described in this specification should be understood as follows.

Singular expressions should be understood to include plural expressions unless the context clearly defines otherwise, and terms such as “first” and “second” are used to distinguish one component from another, The scope of rights should not be limited by these terms.

It should be understood that terms such as "comprise" or "having" do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

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, but also two of the first item, the second item, and the third item. It means a combination of all items that can be presented from one or more.

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

2 is a block diagram showing a touch screen device according to an embodiment of the present invention. FIG. 3 is an exemplary diagram illustrating pixels, touch electrodes, touch driving lines, and a touch driver of the display panel of FIG. 2 . FIG. 4 is an exemplary view showing the pixels of FIG. 3 in detail. Hereinafter, a touch screen device according to an embodiment of the present invention will be schematically described in conjunction with FIGS. 2 to 4 .

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, but is not limited thereto. That is, the touch screen device according to an embodiment of the present invention can be implemented with other capacitance methods such as a mutual capacitance method.

In addition, the touch screen device according to an embodiment of the present invention has been described mainly in that the touch electrodes are implemented as an in-cell type included in the display panel 10, but 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, the touch screen device according to an embodiment of the present invention has been described mainly as a liquid crystal display (LCD), but 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 (OLED), a plasma display device, or an electrophoresis display device.

As shown in FIG. 2, the touch screen device according to an embodiment of the present invention includes a display panel 10, a gate driver 20, a data driver 30, a timing controller 40, a touch driver 50, and a touch coordinate calculator. (60), and a main processor (70).

The display panel 10 includes a lower substrate, an upper substrate, and a liquid crystal layer interposed between the lower and upper substrates. On the lower substrate of the display panel 10, 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 touch driving lines C1 ~ Cp, p is a positive integer of 2 or more) is formed. The data lines D1 to Dm and the touch driving lines C1 to Cp may cross the gate lines G1 to Gn.

Pixels P may be formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn, as shown in FIG. 2 . Each of the pixels P may be connected to a data line and a gate line. Each of the pixels P may include a transistor T, a pixel electrode 11, a liquid crystal cell 13, and a storage capacitor Cst, as shown in FIG. 4 . 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 11 . The touch electrode 12 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 12, the touch electrode 12 serves as a common electrode. Due to this, each of the pixels P drives the liquid crystal of the liquid crystal cell 13 by an electric field generated by a potential difference between the data voltage supplied to the pixel electrode 11 and the common voltage supplied to the touch electrode 12. 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 11 and the touch electrode 12 to maintain a constant voltage difference between the pixel electrode 11 and the touch electrode 12 .

A plurality of touch electrodes 12 are formed on the display panel 10 as shown in FIG. 3 . Each of the touch electrodes 12 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 12 may be set in consideration of a contact area of a finger and a contact area of a pen.

Each of the touch electrodes 12 may be connected to one of the touch driving lines C1 to Cp as shown in FIG. 3 . Each of the touch driving lines C1 to Cp connects each of the touch electrodes 12 and the touch driver 50 . As shown in FIG. 5 , the touch electrodes 12 receive the common voltage Vcom from the touch driver 50 during the display driving period DP through the touch driving lines C1 to Cp, and during the touch sensing period TP. Touch driving voltages VD1 to VDp may be supplied. When the common voltage Vcom is supplied to the touch electrodes 12, the touch electrodes 12 serve as a common electrode. The touch driving lines C1 to Cp may be disposed between two adjacent pixels as shown in FIG. 3 .

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 a lower substrate of the display panel 10 .

A polarizer is attached to each of the upper and lower substrates 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 of the display panel 10 to maintain a cell gap of the liquid crystal cell.

A backlight unit may be disposed under the rear surface of the lower substrate 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 40 . 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 does not supply gate signals to the gate lines G1 to Gn during the touch sensing period TP. In another embodiment, the gate driver 20 may use the touch driving voltage VD1 during the touch sensing period TP to remove an effect of the touch driving voltages VD1 to VDp applied to the touch electrodes during the touch sensing period TP. ~ VDp) and gate signals having the same frequency and the same swing width may be supplied to each of the gate lines G1 to Gn.

The data driver 30 receives digital video data DATA and a data control signal DCS from the timing controller 40 . 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 does not supply data voltages to the data lines D1 to Dm during the touch sensing period TP. In another exemplary embodiment, the data driver 30 may use the touch driving voltage VD1 during the touch sensing period TP to remove an effect of the touch driving voltages VD1 to VDp applied to the touch electrodes during the touch sensing period TP. ~ VDp) and data control signals having the same frequency and the same swing width may be supplied to each of the data lines D1 to Dm.

The timing controller 40 receives digital video data DATA and timing signals TS from the main processor 70 . 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 signal that is briefly repeated at a predetermined cycle.

The timing controller 40 divides one frame period into a display driving period (DP) and a touch sensing period (TP) as shown in FIG. Gate signals are supplied to the G1 to Gn, and the data driver 30 controls the data voltages to be supplied to the data lines D1 to Dm. 5 illustrates that one frame period includes one display driving period DP and one touch sensing period TP, but is not limited thereto. That is, one frame period may include a plurality of display driving periods DP and a plurality of touch sensing periods TP.

The timing controller 40 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 40 outputs the gate control signal GCS to the gate driver 20 and outputs the digital video data DATA and the data control signal DCS to the data driver 30 .

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

The touch driver 50 receives the mode signal MODE from the timing controller 40, receives the touch control signal TCS from the touch coordinate calculation unit 60, and receives the common voltage Vcom from a power supply source (not shown). ) is entered.

The touch driver 50 operates 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. 5 . When the mode signal MODE of the first logic level voltage is input, the touch driver 50 supplies the common voltage Vcom to the touch driving lines C1 to Cp during the display driving period DP as shown in FIG. 5 . The touch driver 50 generates touch driving voltages VD1 to VDp according to the touch control signal TCS during the touch sensing period TP when the mode signal MODE of the second logic level voltage is input. As shown in FIG. 5 , the touch driving voltages VD1 to VDp may be supplied to the touch driving lines C1 to Cp in a predetermined order during the touch sensing period TP. The predetermined order may be a sequential order as shown in FIG. 5 . In FIG. 5 , it has been mainly described that the touch driving voltages VD1 to VDp have higher level voltages than the common voltage Vcom, but it is not limited thereto. Each of the touch driving voltages VD1 to VDp may include a plurality of pulses as shown in FIG. 5 . The touch driver 50 converts the sensing signals from the touch electrodes 12 into touch raw data TRD and outputs the converted touch coordinate calculator 60 .

A detailed description of the operation of the touch driver 50 during the touch sensing period TP will be described later with reference to FIGS. 6 to 8 .

The touch coordinate calculator 60 receives touch row data TRD from the touch driver 50 . 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 12 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 the main processor 70 .

The main processor 70 is a central processing unit (CPU) 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. ), a host processor, an application processor, or a graphic processing unit (GPU).

The main processor 70 converts the digital video data DATA into a format suitable for display on the display panel 10 and transmits it to the timing controller 40 . The main processor 70 may receive touch coordinate data CD from the touch coordinate calculator 60 . The main processor 70 executes an application program or an application program of an icon existing at the touch coordinates according to the touch coordinate data CD, and transmits digital video data DATA and timing signals TS according to the execution program to the timing control unit. Send to (40).

Hereinafter, a touch driver according to an embodiment of the present invention will be described in more detail with reference to FIGS. 6 to 8 .

6 is a block diagram showing the configuration of a touch driver according to an embodiment in more detail, and FIG. 7 is a touch voltage sensing unit connected to a qth touch driving line connected to a qth touch electrode among touch electrodes. It is a block diagram showing the configuration, and FIG. 8 is a diagram showing an operation timing diagram of the touch voltage sensing unit shown in FIG. 7 .

As shown in FIG. 6, the touch driver 50 according to an embodiment of the present invention includes a control signal generator 80, a sensing circuit 90, a multiplexer 100, an analog-to-digital converter 110, a digital An integrator 120 and an interface unit 130 are included.

The control signal generation unit 80 generates a control signal for controlling the touch driver 50 according to the touch control signal TSS transmitted from the touch coordinate calculator 60 through the interface unit 130 . More specifically, as shown in FIG. 8 , the control signal generator 80 generates a reset signal RCS for each unit touch sensing period TSP allocated to sense a touch for each touch electrode 12, It is provided to the sensing circuit unit 90. In one embodiment, the unit touch sensing period (TSP) may be set to the same time as the touch sensing period (TP).

In particular, the control signal generator 80 according to the present invention uses the unit touch sensing period TSP allocated for each touch electrode 12 as a plurality of sub-sensing periods SSP1 to SSPn and a plurality of sub-reset periods SRP1 to SSPn. A sub-reset signal (SRCS) for alternately driving with SRPn is generated and provided to the sensing circuit unit 90.

In the present invention, driving the unit touch sensing period (TSP) allocated to each touch electrode 12 alternately with a plurality of sub-sensing periods (SSP1 to SSPn) and a plurality of sub-reset periods (SRP1 to SRPn) is a unit touch When the touch voltage of the touch electrode 12 is sensed over the entire sensing period TSP, not only the capacitance but also the parasitic capacitance when calculating the output voltage Vout of each touch voltage sensing unit 62 included in the sensing circuit unit 90 This is because the output voltage Vout of each touch voltage sensing unit 62 may deviate from a predetermined allowable range of the touch voltage sensing unit 62 and become saturated because the voltage is continuously accumulated and increased.

That is, in the present invention, each touch voltage sensing unit 62 included in the sensing circuit unit 90 divides the voltage charged in the capacitance and parasitic capacitance of the touch electrode 12 during the sub-sensing period SSP1 to SSPn, and resets the touch voltage sensing unit 62 through the sub-reset period SRP1 to SRPn whenever the sub-sensing period SSP1 to SSPn ends. Through this, it is possible to prevent the output voltage Vout of the touch voltage sensing unit 62 from being saturated beyond a predetermined allowable range of the touch voltage sensing unit 62 .

In an exemplary embodiment, the control signal generator 80 operates the touch voltage sensing unit 62 during the sub-sensing period SSP1 to SSPn while the first logic level is maintained, and is maintained at the second logic level. The sub reset signal SRSP may be generated so that the touch voltage sensing unit 62 is driven during the sub reset period SRP1 to SRPn for a period of time.

The sensing circuit unit 90 is for sensing the touch of each touch electrode 12 and includes a plurality of touch voltage sensing units 62 for sensing the touch of each touch electrode 12 . The touch voltage sensing unit 62 is connected to each touch driving line connected to each touch electrode 12 and senses a touch of each touch electrode 12 . Each touch voltage sensing unit 62 senses the touch of the touch electrode 12 and provides the output voltage Vout calculated by sensing the touch to the analog-to-digital converter 110 through the multiplexer 100 .

Hereinafter, the configuration of the touch voltage sensing unit 62 will be described in more detail with reference to FIG. 7 .

7 is a configuration of the touch voltage sensing unit 62 connected to the qth touch driving line Cq connected to the qth touch electrode (where q is a positive integer satisfying 1≤q≤p) among a plurality of touch electrodes. is shown

The touch voltage sensing unit 62 is connected to the touch electrode TEq through the qth touch driving line Cq and generates a voltage Va charged in the parasitic capacitance Cp and capacitance Cs of the touch electrode TEq. senses To this end, as shown in FIG. 7 , the touch voltage sensing unit 62 includes a touch driving voltage output unit 140 , an operational amplifier 150 , a feedback capacitor 160 , and a reset switch 170 .

The touch driving voltage output unit 140 is connected to the touch driving line Cq and outputs the touch driving voltage VDq to the touch electrode TEq. Specifically, the touch driving voltage output unit 140 outputs the touch driving voltage VDq to the touch electrode TEq through the qth touch driving line Cq during the unit touch sensing period TSP according to the touch control signal TSS. supply

The touch electrode TEq is connected to the qth touch driving line Cq. In FIG. 7 , reference numeral “Rq” denotes resistance of the qth touch driving line Cq. As shown in FIG. 3 , the touch electrode TEq may overlap not only the pixels P, but also gate lines, data lines, or other touch driving lines. Parasitic capacitance (Cp) may be formed between the pixel electrodes and gate lines, data lines, or other touch driving lines as shown in FIG. 7 . In addition, capacitance Cs may be formed between the touch electrode TEq and a person's finger or pen, as shown in FIG. 7 . Parasitic capacitance Cp and capacitance Cs are formed in the touched touch electrode TEq, but only parasitic capacitance Cp is formed in the non-touched touch electrode. In FIG. 7 , only the touch electrode TEq where a touch is generated is illustrated for convenience of description.

The operational amplifier 150 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 150 is connected to the qth touch driving line Cq, the second input terminal IN2 is connected to the initialization voltage line VREFL to which an initialization voltage is supplied, and outputs Terminal (o) is connected to the analog-to-digital converter 110.

At this time, although not shown in FIG. 7 , a storage capacitor Cs may be further included between the output terminal o and the analog-to-digital converter 110 . The storage capacitor Cs is connected between the output terminal o and the ground voltage source to charge the output voltage Vout of the output terminal o.

The feedback capacitor (Cfb, 160) is connected between the first input terminal (IN1) and the output terminal (o) of the operational amplifier (150).

The reset switch 170 resets the feedback capacitor 160 according to the reset signal RCS received from the control signal generator 80 for each unit touch sensing period TSP. In particular, the reset switch 170 according to the present invention additionally resets the feedback capacitor 170 according to the sub reset signal SRCS received from the control signal generator 80 during the unit touch sensing period TSP.

That is, the reset switch 170 is turned off during the time sub-sensing period SSP1 to SSPn during which the sub-reset signal SRCS is maintained at the first logic level, so that the touch voltage sensing unit 62 detects the voltage of the touch electrode TEq. It senses and outputs the output voltage (Vout). In addition, the reset switch 170 is turned on during the sub-reset period SRP1 to SRPn in which the sub-reset signal SRCS is maintained at the second logic level to reset the feedback capacitor 76, thereby resetting the output of the touch voltage sensing unit 53. This causes the voltage (Vout) to be reset.

According to the operation of the reset switch 170, the output voltage Vout output from the operational amplifier 150 during each sub-sensing period SSP1 to SSPn is as shown in Equation 1 below.

[Equation 1]

Voutn=((Cs+Cp)/Cfb)*Vt

In Equation 1, "Voutn" represents the output voltage of the operational amplifier 150 during the nth sub-sensing period SSPn, "Cs" represents the capacitance of the touch electrode TEq, and "Cp" represents the touch electrode (TEq) represents the parasitic capacitance, “Cfb” represents the capacitance of the feedback capacitor 160, and “Vt” represents the voltage charged in the parasitic capacitance (Cp) and capacitance (Cs) of the touch electrode (TEq). .

As described above, in the present invention, since the reset switch 170 resets the feedback capacitor 160 according to the sub-reset signal SRCS received from the control signal generator 80 during the unit touch sensing period TSP, the touch electrode The voltage charged in (12) can be divided and sensed during a plurality of sub-sensing periods SSP1 to SSPn, thereby preventing the output voltage of the touch voltage sensing unit 62 from being saturated.

The multiplexer 100 (Multiplex: MUX) outputs an output from any one of a plurality of touch voltage sensing units 62 in response to a touch control signal TCS transmitted from the touch coordinate calculator 60 through the interface unit 130. The output voltage Vout is output to the analog-to-digital conversion unit 110.

In particular, the multiplexer 100 according to the present invention outputs voltages calculated during sub-sensing periods (SSP1 to SSPn) for each touch voltage sensing unit 62 within a unit touch sensing period (TSP) allocated to each touch electrode 12. (Voutn) is transferred to the analog-to-digital conversion unit 110.

The analog-to-digital conversion unit 110 converts the output voltages Vout1 to Voutn for each sub-sensing period SSP to SSPn of each touch voltage sensing unit 62 output from the multiplexer 100 into sub-touch raw data, which is digital data. Convert to (STRD1 to STRDn). That is, the analog-to-digital conversion unit 110 converts the first output voltage Vout1 calculated during the first sub-sensing period SSP1 into first sub-touch raw data STRD1 that is digital data, and converts the n-th sub-sensing period The nth output voltage Voutn calculated during (SSPn) is converted into nth sub-touch raw data STRDn.

The analog-to-digital converter 110 transmits sub-touch raw data STRD1 to STRDn calculated for each touch electrode 12 to the digital integrator 120 during the unit touch sensing period TSP.

The digital integrator 120 digitally integrates the sub-touch raw data (STRD1 to STRDn) for each touch electrode 12 transmitted from the analog-to-digital conversion unit 110 to generate the values of each touch electrode 12 during a unit touch sensing period (TSP). ) of the touch row data TRD is calculated. That is, the digital integrator 120 calculates the first output voltage Vout1 calculated during the first sub-sensing period SSP1 from the first sub-touch raw data STRD1 to the n-th sub-sensing period SSPn. Touch raw data of each touch electrode 12 during the unit touch sensing period TSP is calculated by summing all the n th sub-touch raw data STRDn for the n output voltage Voutn.

The digital integrator 120 outputs the calculated touch raw data TRD to the touch coordinate calculation unit 60 through the interface unit 66 .

The interface unit 130 receives the touch control signal TSS from the touch coordinate calculation unit 60 and transfers it to the touch voltage sensing units 62, and transmits the touch voltage sensing unit 62 to each touch electrode 12 received from the digital integrator 120. The touch row data TRD is transferred to the touch coordinate calculator 60 .

9(a) is a view showing touch raw data obtained when the voltage of a touch electrode is divided and sensed n times during a unit touch sensing period according to the present invention, and FIG. 9(b) shows a unit touch sensing period according to the prior art This is a diagram showing touch raw data obtained when the voltage of the touch electrode is sensed without being divided during the period.

As can be seen from FIG. 9( b ), when the voltage of the touch electrode is sensed without being divided during the unit touch sensing period, since the output voltage of the touch voltage sensing unit is saturated, accurate touch raw data cannot be obtained. However, as shown in FIG. 9(a), when the voltage of the touch electrode is sensed by dividing it n times during a unit touch sensing period according to the present invention, accurate touch raw data is obtained because the output voltage of the touch voltage sensing unit is not saturated. it can be seen that

Hereinafter, a method of driving a touch screen device according to the present invention will be described in more detail with reference to FIG. 10 .

10 is a flowchart showing a method of driving a touch screen device according to an embodiment of the present invention.

The method for driving a touch screen illustrated in FIG. 10 may be applied to a touch screen device having a configuration illustrated in FIGS. 2 to 7 .

As shown in FIG. 10, the voltage charged in the feedback capacitor 160 is reset by turning off the reset switch 170 according to the reset signal RCS (S900).

Thereafter, the voltage charged in the touch electrode 12 is sensed by maintaining the reset switch 170 in an off state during the first sub-sensing period SSP1 in which the sub-reset signal SRCS is maintained at the first logic level, thereby sensing the first sub-sensing period SSP1. The output voltage (Vout1) is calculated (S910). At this time, the first output voltage is calculated by sensing the voltage charged in the parasitic capacitance Cp and capacitance Cs of the touch electrode 12 by applying the touch driving voltage VD to the touch electrode 12. .

Thereafter, first sub-touch raw data is generated by converting the first output voltage Vout1 into digital (S920).

Thereafter, during the first sub-reset period SRP1 in which the sub-reset signal SRCS is maintained at the second logic level, the voltage charged in the feedback capacitor Cfb is reset by maintaining the reset switch 170 in an on state to reset the first sub-reset period SRP1. The output voltage Vout1 is reset (S930). Accordingly, the output voltage Vout of the operational amplifier 150 is reset to the initialization voltage during the first sub-reset period SRP1.

Thereafter, it is determined whether the sub-sensing period and the sub-reset period have been repeated n times (S940), and if they have been repeated n times, the first sub-touch calculated during the first sub-sensing period SSP1 to the n-th sub-sensing time SSPn is determined (S940). Touch raw data TDR is calculated by digitally integrating raw data STDR1 to n th sub-touch raw data STDRn (S950).

In an embodiment, digital integration may be performed by summing first sub-touch raw data STDR1 to n-th sub-touch raw data STDRn.

Then, touch coordinates are obtained using the touch raw data calculated in S950 (S960).

Meanwhile, if the sub-sensing period and the sub-reset period are not repeated n times in S940, S910 to S930 are repeated until the sub-sensing period and the sub-reset period are n times.

Those skilled in the art to which the present invention pertains will be able to understand that the above-described present invention may be embodied in other specific forms without changing its technical spirit or essential features.

For example, in the above-described embodiment, it has been described that the output voltage of the touch voltage sensing unit 62 is reset during the sub-reset period by using the reset switch 170 included in the touch voltage sensing unit 62 .

However, in a modified embodiment, the present invention resets the output voltage of the touch voltage sensing unit 62 during the sub-reset period by adding a separate switch in addition to the reset switch 170 included in the touch voltage sensing unit 62. you might be able to do it

Through this, the output voltage of the touch voltage sensing unit 62 is reset or the voltage charged in the touch electrode is divided without changing the on/off timing of the reset switch 170 included in the existing touch voltage sensing unit 62. so that it can be sensed.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention. do.

10: display panel 20: gate driver
30: data driver 40: timing controller
50: touch drive unit 60: touch coordinate calculation unit
70: main processor 80: control signal generator
90: sensing circuit unit 100: multiplexer
110: analog to digital conversion unit 120: digital integrator
130: interface unit

Claims (10)

During a unit touch sensing period configured by alternating a plurality of sub-sensing periods and a plurality of sub-reset periods, the output voltage is calculated by sensing the voltage charged in the capacitance and parasitic capacitance of the touch electrode for each sub-sensing period, and the sub-reset a touch voltage sensing unit resetting the output voltage to an initialization voltage at each period;
an analog-to-digital conversion unit converting the output voltage of the touch voltage sensing unit calculated for each sub-sensing period into sub-touch raw data, which is digital data; and
a digital integrator calculating touch row data of the unit touch sensing period by accumulating a plurality of sub-touch row data for the touch electrode, which are calculated during the unit touch sensing period;
The touch voltage sensing unit
The touch characterized in that the output voltage increased from the initialization voltage is calculated in each of the plurality of sub sensing periods by dividing and sensing a voltage charged in the capacitance and parasitic capacitance of the touch electrode in the plurality of sub sensing periods. screen device. According to claim 1,
The touch voltage sensing unit,
an operational amplifier including a first input terminal to which a touch driving line connected to the touch electrode is connected, a second input terminal to which a reference voltage is supplied, and an output terminal;
a feedback capacitor connected to the first input terminal and the output terminal; and
and a reset switch for resetting the feedback capacitor. According to claim 2,
The touch screen device of claim 1 , wherein the reset switch is turned on during the sub-reset period to reset the voltage charged in the feedback capacitor. According to claim 1,
and a control signal generator generating a sub-reset signal for alternately dividing the unit touch sensing period into the plurality of sub-sensing periods and the plurality of sub-reset periods and supplying the generated sub-reset signal to the touch voltage sensing unit. screen device. According to claim 4,
The sub-sensing period is a period in which the sub-reset signal is maintained at a first logic level, and the sub-reset period is a period in which the sub-reset signal is maintained at a second logic level. According to claim 5,
The sub-reset signal is turned off while being maintained at the first logic level so that a voltage charged in capacitance and parasitic capacitance of the touch electrode is sensed, and while the sub-reset signal is maintained at the second logic level. The touch screen device further comprises a reset switch turned on to reset the output voltage. According to claim 1,
The touch voltage sensing unit,
The touch screen device further comprises a touch driving voltage output unit outputting a touch driving voltage to the touch electrodes to charge capacitance and parasitic capacitance of the touch electrodes. charging capacitance and parasitic capacitance of the touch electrode with a touch driving voltage in a touch voltage sensing unit;
The touch voltage sensing unit senses and outputs a voltage charged in capacitance and parasitic capacitance of the touch electrode for each sub-sensing period during a unit touch sensing period in which a plurality of sub-sensing periods and a plurality of sub-reset periods are alternately configured. calculating the voltage;
resetting, by the touch voltage sensing unit, the output voltage to an initialization voltage for each sub-reset period;
converting, by an analog-to-digital converter, the output voltage calculated for each sub-sensing period into sub-touch raw data that is digital data; and
calculating, in a digital integrator, touch row data of the unit touch sensing period by accumulating a plurality of sub-touch row data for the touch electrode, generated during the unit touch sensing period;
The touch voltage sensing unit
The touch characterized in that the output voltage increased from the initialization voltage is calculated in each of the plurality of sub sensing periods by dividing and sensing a voltage charged in the capacitance and parasitic capacitance of the touch electrode in the plurality of sub sensing periods. How to drive a screen device. According to claim 8,
and generating, by a control signal generator, a sub reset signal for alternately dividing the unit touch sensing period into the plurality of sub sensing periods and the plurality of sub reset periods. driving method. According to claim 9,
The sub-sensing period is a period in which the sub-reset signal is maintained at a first logic level, and the sub-reset period is a period in which the sub-reset signal is maintained at a second logic level.

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