KR102520692B1 - Touch sensing system - Google Patents

Abstract

The touch driving device of the present invention includes a display panel including a pixel array in which touch sensors are embedded, and a touch period for driving the touch sensors within one display frame period displaying an input image by driving the touch sensors during a touch period. A first period including a touch driving device for allocating at least two or more, and a first period from the start of a K th display frame (where K is a positive integer) to the first touch reporter of the K th display frame is: It is different from the second period from the start of the display frame to the first touch reporter of the K+1 th display frame.

Description

Touch Sensing System {TOUCH SENSING SYSTEM}

The present invention relates to a touch sensing system including a capacitive touch sensor.

A user interface (UI) allows a person (user) to easily control various electronic devices as he/she wants. Representative examples of such a user interface include a keypad, a keyboard, a mouse, an on-screen display (OSD), a remote controller having an infrared communication function or a radio frequency (RF) communication function, and the like. User interface technology continues to evolve in the direction of enhancing user sensibility and convenience of operation. Recently, user interfaces are evolving into touch UIs, voice recognition UIs, 3D UIs, and the like.

Touch UI is essential for portable information devices. The touch UI is implemented as a method of forming a touch screen on a screen of a display device. Such a touch screen may be implemented in a capacitive manner. A touch screen having a capacitive touch sensor senses a touch input by sensing a change in capacitance, that is, a change in charge of the touch sensor, when a finger or a conductive material contacts (or approaches) the touch sensor.

The capacitive touch sensor may be implemented as a self capacitance sensor or a mutual capacitance sensor. Each of the electrodes of the self-capacitance sensor may be connected 1:1 to sensor wires formed along one direction. A mutual capacitance sensor may be formed between adjacent sensor electrodes.

Referring to FIG. 1 , a wire 4 is connected to each of the electrodes 2 of the self-capacitance sensor Cs. The self-capacitance sensor Cs includes capacitance formed on each of the electrodes 2 . When a touch driving signal is applied to the electrode 2 through the wire 4, charge Q is accumulated in the self-capacitance sensor Cs. At this time, when a finger or a conductive object comes into contact with the electrode 4, the capacitance value of the self-capacitance sensor Cs is changed as the conductive capacitance Cf is additionally connected to the self-capacitance sensor Cs. Therefore, since the capacitance value is different between the sensor where the finger is touched and the sensor where it is not, it is possible to determine whether the finger is touched.

However, since the number of wires 4 connected to the self-capacitance sensors Cs is large, the touch sensing system using the self-capacitance sensor Cs as shown in FIG. 1 has a dead zone in which the wires 14 are routed. (Dead zone) is large. A dead zone is an area in which a touch input cannot be sensed.

Such a conventional touch sensing system using a self-capacitance sensor has a large dead zone, so electrodes of the sensors cannot be densely formed, and thus the touch resolution is low. When the number of touch sensors is increased in order to increase touch resolution, the number of wires 14 increases, so the dead zone becomes larger. As a result, in the conventional touch sensing system, it is difficult to improve resolution and sensing sensitivity and accuracy due to structural problems of the self-capacitance sensor. Also, when the number of touch sensors increases in a conventional touch sensing system, the number of channels of a touch sensing integrated circuit (hereinafter referred to as "IC") increases, and thus the size of the IC chip increases.

Accordingly, an object of the present invention is to provide a touch sensing system capable of increasing touch hashing degree, sensing sensitivity, and accuracy without increasing the number of touch sensors.

In order to achieve the above object, the touch sensing system of the present invention includes self-capacitance sensors provided on each of the sensor electrodes, mutual capacitance sensors provided between adjacent sensor electrodes, and sensor wires connected to the sensor electrodes. a touch screen comprising: sensing a touch input to the self-capacitance sensors according to a first touch drive signal in a first sensing mode; and sensing a touch input to the mutual capacitance sensors according to a second touch drive signal in a second sensing mode. A touch driving circuit for sensing a touch input is provided. Here, the touch driving circuit includes: a sensing unit for sensing the touch input; a multiplexer for selectively connecting a first input terminal of the sensing unit to one of the sensor wires; a driving signal selector configured to apply a touch driving signal to sensor wires not connected to the sensing unit and to apply the second touch driving signal to sensor wires connected to the sensing unit in the second sensing mode; and a reference signal selector configured to apply the first touch driving signal to a second input terminal of the sensing unit in a sensing mode and to apply a reference voltage to a second input terminal of the sensing unit in the second sensing mode.

In the second sensing mode, a base voltage or DC voltage is applied to sensor wires other than the first sensor wire to which the second touch driving signal is applied and the second sensor wire connected to the first input terminal of the sensing unit.

In the second sensing mode, a sensor electrode connected to the first sensor wire and a sensor electrode connected to the second wire are adjacent to each other.

The sensing unit includes an odd sensing unit for selectively sensing a touch input to odd sensor electrodes connected to odd sensor wires among the sensor wires, and excellent sensor electrodes connected to excellent sensor wires among the sensor wires. An even number sensing unit for selectively sensing a touch input for an odd number sensing unit, wherein the multiplexer comprises: an odd number multiplexer selectively connecting a first input end of the odd number sensing unit to one of the odd number sensor wires; and an even multiplexer selectively connecting an input terminal to any one of the even sensor wires, wherein the odd number sensing unit and the even sensing unit are operated simultaneously, and the odd number multiplexer and the even multiplexer are operated simultaneously.

The touch driving circuit, in the first sensing mode, applies the first touch driving signal to a first sensor electrode and a second sensor electrode adjacent to each other, so that a first self-capacitance sensor provided in the first sensor electrode A touch input to a second self-capacitance sensor provided in the second sensor electrode is sensed through the second sensor electrode while simultaneously sensing a touch input to the first sensor electrode.

The sensor electrodes include a first sensor electrode, a second sensor electrode adjacent to the first sensor electrode, a third sensor electrode adjacent to the second sensor electrode, a fourth sensor electrode adjacent to the third sensor electrode, and the When the fifth sensor electrode is disposed in order adjacent to the fourth sensor electrode, the touch driving circuit applies the second touch driving signal to the second sensor electrode in the second sensing mode to connect the first sensor electrode and the sensor electrode to the second sensor electrode. A touch input to the first mutual capacitance sensor provided between the second sensor electrodes is sensed through the first sensor electrode, and at the same time, the second touch driving signal is applied to the fifth sensor electrode so that the fourth sensor electrode A touch input to the second mutual capacitance sensor provided between the first sensor electrode and the fifth sensor electrode is sensed through the fourth sensor electrode, and a base voltage or a direct current voltage is applied to the third sensor electrode.

The sensor electrodes are arranged in the order of a first sensor electrode, a second sensor electrode adjacent to the first sensor electrode, a third sensor electrode adjacent to the second sensor electrode, and a fourth sensor electrode adjacent to the third sensor electrode. When disposed, the touch driving circuit applies the second touch driving signal to a second sensor electrode in the second sensing mode to provide a first mutual capacitance sensor provided between the first sensor electrode and the second sensor electrode. The second mutual capacitance provided between the third sensor electrode and the fourth sensor electrode by applying the second touch driving signal to the third sensor electrode while sensing a touch input for the first sensor electrode through the first sensor electrode. A touch input to the sensor is sensed through the fourth sensor electrode.

The touch driving circuit alternately senses the first sensing mode and the second sensing mode by parts of the self-capacitance sensors and the mutual capacitance sensors.

The touch driving circuit alternately senses all of the self-capacitance sensors and the mutual-capacitance sensors in the first sensing mode and the second sensing mode.

The touch sensing system of the present invention senses a touch input at each of the sensor electrodes using self-capacitance sensors and also senses a touch input between sensor electrodes using mutual capacitance sensors, without increasing the number of touch sensors. The resolution, sensing sensitivity and accuracy of the touch screen may be improved.

1 is a diagram showing electrodes and wiring structures of a touch screen including self-capacitance sensors;
2 is a block diagram showing a touch sensing system according to an embodiment of the present invention;
3 is a diagram showing an example in which a touch sensor is embedded in a pixel array;
FIG. 4 is a timing diagram illustrating a method of time-divisionally driving pixels and touch sensors of the display panel shown in FIG. 3;
5 and 6 are views showing multiplexers and sensing units connected to touch sensors;
7 is a diagram for explaining signals applied to a multiplexer and a sensing unit in a first sensing mode for sensing a change in capacitance of self-capacitance sensors;
8 is a diagram for explaining signals applied to a multiplexer and a sensing unit in a second sensing mode for sensing a change in capacitance of mutual capacitance sensors;
9 to 11 are diagrams showing a sensing channel selection sequence of multiplexers in a first sensing mode and a sensing target electrode accordingly;
12 to 14 are diagrams illustrating an order of selecting a sensing channel of multiplexers in a second sensing mode and a sensing target electrode accordingly;
15 to 17 are diagrams showing another sensing channel selection sequence of multiplexers in a second sensing mode and sensing target electrodes accordingly;
18 is a diagram showing an example of alternately sensing parts of self-capacitance sensors and mutual-capacitance sensors within a touch period;
19 is a diagram showing an example of alternately sensing all self-capacitance sensors and mutual-capacitance sensors within a touch period;

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Like reference numbers throughout the specification indicate substantially the same elements. In the following description, if it is determined that a detailed description of a known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

2 shows a touch sensing system according to an embodiment of the present invention. 3 shows an example in which a touch sensor is embedded in a pixel array. And, FIG. 4 shows a method of time-division driving the pixels and touch sensors of the display panel as shown in FIG. 3 .

2 to 4 , the touch sensing system of the present invention includes a display device and a touch module.

Display devices include Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP), and Organic Light Emitting Display (OLED). , Electrophoresis (EPD) can be implemented based on a flat panel display device. In the following embodiments, it is described that the display device is implemented as a liquid crystal display device, but the display device of the present invention is not limited to the liquid crystal display device.

The display device may include a display panel DIS, display driving circuits 12, 14, and 16, and a host system 19.

The display panel DIS includes a liquid crystal layer formed between two sheets of substrates. The pixel array of the display panel DIS includes pixels formed in a pixel area defined by data lines (D1 to Dm, where m is a positive integer) and gate lines (G1 to Gn, where n is a positive integer). . Each of the pixels is connected to TFTs (Thin Film Transistors) formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode that charges the data voltage, and a pixel electrode to form a liquid crystal cell. A storage capacitor (Cst) for maintaining a voltage may be included.

A black matrix, a color filter, and the like may be formed on the upper substrate of the display panel DIS. A lower substrate of the display panel DIS may be implemented as a color filter on TFT (COT) structure. In this case, the black matrix and color filters may be formed on the lower substrate of the display panel DIS. The common electrode to which the common voltage is supplied may be formed on an upper substrate or a lower substrate of the display panel DIS. A polarizing plate is attached to each of the upper and lower substrates of the display panel DIS, and an alignment layer for setting a pretilt angle of the liquid crystal is formed on an inner surface in contact with the liquid crystal. A column spacer for maintaining a cell gap of the liquid crystal cell is formed between the upper substrate and the lower substrate of the display panel DIS.

A backlight unit may be disposed under the rear surface of the display panel DIS. The backlight unit is implemented as an edge type or direct type backlight unit and irradiates light to the display panel DIS. The display panel DIS may be implemented in any known liquid crystal mode, such as a twisted nematic (TN) mode, a vertical alignment (VA) mode, an in plane switching (IPS) mode, and a fringe field switching (FFS) mode.

The display driving circuit includes a data driving circuit 12, a gate driving circuit 14, and a timing controller 16 to write video data of an input image to pixels of the display panel DIS. The data driving circuit 12 converts the digital video data (RGB) input from the timing controller 16 into an analog positive/negative polarity gamma compensation voltage and outputs a data voltage. The data voltage output from the data driving circuit 12 is supplied to the data lines D1 to Dm. The gate driving circuit 14 sequentially supplies a gate pulse (or scan pulse) synchronized with the data voltage to the gate lines G1 to Gn to select a pixel line of the display panel DIS to which the data voltage is written.

The timing controller 16 inputs timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable signal (Data Enable, DE), and a main clock (MCLK) input from the host system 19. and the operation timings of the data driving circuit 12 and the gate driving circuit 14 are synchronized. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data timing control signal includes a source sampling clock (SSC), a polarity control signal (Polarity, POL), a source output enable signal (Source Output Enable, SOE), and the like.

The host system 19 transmits the timing signals (Vsync, Hsync, DE, MCLK) together with the digital video data (RGB) to the timing controller 16, and touch coordinate information (XY) input from the touch driving circuit 18. ) and associated applications can be executed.

The touch module includes a touch screen (TSP) and a touch driving circuit 18 .

The touch screen TSP includes a plurality of sensor electrodes C1 to C4 and sensor wires L1 to L4 connected to each of the sensor electrodes C1 to C4. The touch sensors of the touch screen TSP are divided into self-capacitance sensors Cs having self capacitance and mutual capacitance sensors Cm having mutual capacitance. A self-capacitance sensor Cs is formed on each of the sensor electrodes C1 to C4, and a mutual capacitance sensor Cm is formed on the adjacent sensor electrodes C1 to C4.

In the self-capacitance sensing method, charge is supplied to the self-capacitance sensor Cs by applying a touch driving signal TX to each of the sensor electrodes C1-C4 through the sensor wires L1-L4. Subsequently, when the capacitance change of the self-capacitance sensor Cs is sensed through the sensor electrodes C1 to C4 to which the touch driving signal TX is applied and the sensor wires L1 to L4, the touch on the sensor electrodes C1 to C4 input can be sensed.

In the mutual capacitance sensing method, a touch driving signal TX is applied to one sensor electrode (Tx in FIGS. 12 and 15, etc.) of neighboring sensor electrodes C1 to C4 through sensor wires L1 to L4. to supply charge to the mutual capacitance sensor (Cm), and the capacitance of the mutual capacitance sensor (Cm) through another sensor electrode (Rx in FIGS. 12 and 15) and sensor wiring in synchronization with the touch driving signal (TX) When the change is sensed, a touch input positioned between adjacent sensor electrodes may be sensed. The mutual capacitance sensing method may sense a touch input on the sensor lines L1 to L4.

In this mutual capacitance sensing method, a touch input may be sensed at each position between the sensor electrodes C1 to C4. Therefore, the touch sensing system of the present invention can not only sense a touch input on each of the sensor electrodes using the self-capacitance sensors, but also sense a touch input between the sensor electrodes using the mutual capacitance sensors, thereby increasing the resolution of the touch screen, Sensing sensitivity and accuracy may be improved.

The touch screen TSP may be bonded to the upper polarizing plate of the display panel DIS or formed between the upper polarizing plate of the display panel DIS and the upper substrate. Also, the touch sensors C1 to C4 of the touch screen TSP may be embedded in the pixel array of the display panel DIS as an in-cell type. An example in which the touch screen TSP is embedded in the pixel array of the display panel DIS is shown in FIG. 3 . Referring to FIG. 3 , the pixel array of the display panel DIS includes touch sensors C1 to C4 and sensor lines L1 to Li, where i is smaller than m and n, and is connected to the touch sensors C1 to C4. positive integers). The common electrode COM of the pixels 101 is divided into a plurality of segments. The touch sensors C1 to C4 are implemented with divided common electrodes COM. One common electrode segment is commonly connected to a plurality of pixels 101 and forms one touch sensor. Therefore, as shown in FIG. 4 , the touch sensors C1 to C4 supply the common voltage Vcom to the pixels 101 during the display period Td1 and Td2 for writing image data, and the touch period Tt1 and Tt2 ), it receives the touch drive signal (TX) and senses the touch input.

The touch driving circuit 18 applies the touch driving signal TX to the touch sensors C1 to C4, senses the change in self-capacitance and mutual capacitance of the touch sensors C1 to C4, and then detects the change in the capacitance of the finger (or stylus). It determines whether a conductive material such as a pen is touched and its location.

The touch driving circuit 18 drives the touch sensors C1 to C4 during the touch periods Tt1 and Tt2 in response to the touch enable signal TEN input from the timing controller 16 or the host system 19. . The touch driving circuit 18 senses a touch input by supplying the touch driving signal TX to the touch sensors C1 to C4 through the sensor lines L1 to L4 during the touch periods Tt1 and Tt2. The touch driving circuit 18 determines a touch input by analyzing a change in capacitance of the touch sensor, which varies depending on the presence or absence of a touch input, and calculates the coordinates of the touch input position. Coordinate information of the touch input position is transmitted to the host system 19 in the form of a touch reporter.

The touch driving circuit 18 drives the touch sensors C1 to C4 in response to the touch enable signal TEN during the touch periods Tt1 and Tt2, and controls the touch sensors within one display frame period displaying an input image. By allocating at least two or more touch frames for driving (C1 to C4), the touch report rate can be higher than the display frame rate. Here, a plurality of touch periods corresponding to the number of multiplexers may be included in one touch frame.

For example, if the display period (Td1, Td2) and the touch period (Tt1, Tt2) are divided into a plurality of periods as shown in FIG. , Tt2), the touch input is sensed, and coordinate information of the touch input is transmitted to the host system 19 when each touch frame is completed. Accordingly, the present invention can increase the touch report rate more than the display frame rate. The display frame rate is the frame frequency at which one frame image is written to the pixel array. The touch reporter rate is the rate at which coordinate information of a touch input is generated. The higher the touch reporter rate, the faster the coordinate recognition speed of the touch input, so the touch sensitivity improves.

5 and 6 show multiplexers 140 and sensing units 160 connected to sensor electrodes 22 . 7 is a diagram for explaining signals applied to a multiplexer and a sensing unit in a first sensing mode for sensing a change in capacitance of self-capacitance sensors. 8 is a diagram for explaining signals applied to a multiplexer and a sensing unit in a second sensing mode for sensing capacitance changes of mutual capacitance sensors.

Referring to FIGS. 5 and 6 , the touch driving circuit 18 may include a micro controller unit (MCU) that controls operations of the multiplexers 140 and the sensing units 160 . MCU can be replaced by touch IC.

The multiplexer 140 selectively connects the sensing unit 160 and the sensor electrodes 22 under the control of the MCU. The multiplexer 140 may supply a common voltage Vcom under the control of an MCU. When the resolution of the touch screen is M (horizontal) × N (vertical) (where M and N are each positive integers greater than or equal to 2), the number of multiplexers 140 required may be M. When the resolution of the touch screen is M×N, the sensor electrodes 12 may be divided into M×N numbers. Each multiplexer 140 is connected to N sensor electrodes 22, Y1 to Yn through N sensor wires 115, and the N sensor wires 115 are sequentially connected to one sensing unit 160. can be connected to

The sensing unit 160 is connected to the sensor wires 115 through the multiplexer 140 and converts sensing signals received from the sensor electrodes 12 into digital data. The sensing unit 160 includes an amplifier that amplifies the received sensing signal, an integrator that accumulates the voltage of the amplifier, and an analog-to-digital converter (hereinafter referred to as “ADC”) that converts the voltage of the integrator into digital data. ). The digital data output from the ADC is transmitted to the MCU as touch raw data. When the resolution of the touch screen is M×N, M sensing units 160 may also be required.

The MCU compares touch raw data with a predetermined threshold value, and determines locations of touch sensors having a change amount of charge greater than or equal to the threshold value as the touch input area. The MCU calculates coordinates for each touch input and transmits touch data TDATA including touch input coordinate information to the host system 19 .

The touch driving circuit 18 is connected to the driving power supply unit to receive driving power. The touch driving circuit 18 generates the touch driving signal TX in the touch periods Tt1 and Tt2 in consideration of the touch enable signal TEN and applies it to the sensor electrodes 22 . The touch driving signal TX may be generated in various forms such as a square wave type pulse, a sine wave, a triangular wave, etc., but is preferably implemented as a square wave. The touch driving signal may be applied multiple times to each of the sensor electrodes 22 so that charges may be accumulated multiple times in the integrator of the sensing unit 160 .

The touch driving circuit 18 generates the sensing mode control signal CTRL in the touch periods Tt1 and Tt2 to sense capacitance changes of the self-capacitance sensors in a first sensing mode (hereinafter referred to as “self-sensing mode”). ) and a second sensing mode (hereinafter referred to as “mutual sensing mode”) for sensing changes in capacitance of the mutual capacitance sensors. The touch driving circuit 18 generates the first touch driving signal TXS in the self sensing mode and generates the second touch driving signal TXM in the mutual sensing mode. The first touch driving signal TXS and the second touch driving signal TXM may have the same or different shapes.

The touch driving circuit 18 transmits the first touch driving signal TXS in the self-sensing mode to the sensor wires 115 that are not connected to the first input terminal ((-) input terminal of the amplifier (Amp)) of the sensing unit 160. and selection of a driving signal for applying the second touch driving signal TXM to the sensor wire 115 connected to the first input terminal ((-) input terminal of the amplifier (Amp)) of the sensing unit 160 in the mutual sensing mode. A portion 210 may be included. In addition, the touch driving circuit 18 applies the first touch driving signal TXS to the second input terminal ((+) input terminal of the amplifier (Amp)) of the sensing unit 160 in the self-sensing mode, and in the mutual sensing mode It may include a reference signal selector 220 that applies the reference voltage VREF to the second input terminal (positive input terminal of the amplifier Amp) of the sensing unit 160 .

A case in which the self-capacitance sensor Cs of the sensor electrode Y1 is sensed in the self-sensing mode will be described with reference to FIG. 7 . In the self-sensing mode, when the first touch driving signal TXS is applied to the first input terminal of the sensing unit 160 ((-) input terminal of the amplifier (Amp), the multiplexer 140 outputs the first touch driving signal ( TXS) is selectively applied only to the sensor wire connected to the sensor electrode Y1. Then, the sensing unit 160 senses a change in potential of the sensor electrode Y1 according to the first touch driving signal TXS through the sensor wiring and the multiplexer 140 . Meanwhile, the multiplexer 140 includes sensor wires not connected to the first input terminal ((-) input terminal of the amplifier (Amp) of the sensing unit 160, that is, sensor wires connected to the other sensor electrodes Y2 to Yn. By applying the first touch driving signal TXS also, it is possible to prevent the sensing signal from being distorted due to non-sensed sensor wires. For this purpose, a constant DC voltage other than the first touch driving signal TXS may be applied to the sensor wires connected to the other sensor electrodes Y2 to Yn.

A case in which the mutual capacitance sensor Cm between the sensor electrodes Y1 and Y2 is sensed in the mutual sensing mode will be described with reference to FIG. 8 . In the mutual sensing mode, the multiplexer 140 selectively applies the second touch driving signal TXM only to the sensor wire connected to the sensor electrode Y2. Then, the sensing unit 160 senses a potential change of the sensor electrode Y1 according to the second touch driving signal TXM through the sensor wire connected to the sensor electrode Y1 and the multiplexer 140 . Meanwhile, the multiplexer 140 applies a base voltage or a DC voltage to sensor wires not connected to the sensor electrodes Y1 and Y2 to prevent distortion of sensing signals due to sensor wires that are not sensed. can

9 to 11 show a sensing channel selection sequence of multiplexers in self-sensing mode and a sensing target electrode accordingly.

Referring to FIG. 9 , the touch driving circuit 12 of the present invention can simultaneously sense sensor electrodes in two adjacent rows in a self-sensing mode. In other words, the touch driving circuit 12 applies the first touch driving signal TXS to the first sensor electrode Y1 and the second sensor electrode Y2 adjacent to each other, and is provided on the first sensor electrode Y1. A touch input to the first self-capacitance sensor is sensed through the first sensor electrode Y1, and a touch input to the second self-capacitance sensor provided on the second sensor electrode Y2 is sensed through the second sensor electrode ( It can be sensed through Y1).

To this end, the sensing unit 160 of FIG. 6 , which is responsible for sensing the first row sensor electrodes, touches the sensor electrodes Y1, Y3, ..., Y23 connected to the odd number sensor wires among the sensor wires. An odd number sensing unit (AFE) for selectively sensing, and an excellent number for selectively sensing a touch input to the even sensor electrodes (Y2, Y4, ..., Y22) connected to the good sensor wires among sensor wires. A sensing unit (AFE) is included. In addition, the multiplexer 140 of FIG. 6 in charge of sensing the first row sensor electrodes is an odd multiplexer MUXO that selectively connects the first input terminal (-) of the odd number sensing unit AFE to any one of the odd number sensor wires. ), and an even multiplexer MUXE selectively connecting the first input terminal (-) of the even sensing unit AFE to one of the even sensor lines. Here, the odd number sensing unit AFE and even number sensing unit AFE are operated simultaneously, and the odd number multiplexer MUXO and even number multiplexer MUXE are operated simultaneously.

In the self-sensing mode as shown in FIGS. 10 and 11 , 26*23 (598) sensor electrodes are sensed through a total of 12 sensing operations. In the first sensing (S1), the sensor electrodes (Y1, Y2) are simultaneously sensed, and in the second sensing (S2), the sensor electrodes (Y3, Y4) are simultaneously sensed. In the same principle, the sensor electrodes Y11 and Y12 are simultaneously sensed at the twelfth sensing time (S12).

12 to 14 show a sensing channel selection sequence of multiplexers in a mutual sensing mode and an electrode to be sensed accordingly.

Referring to FIG. 12 , the touch driving circuit 12 of the present invention can simultaneously sense sensor electrodes in two rows spaced apart from each other in a mutual sensing mode. In other words, the sensor electrodes include a first sensor electrode Y1, a second sensor electrode Y2 adjacent to the first sensor electrode Y1, a third sensor electrode Y3 adjacent to the second sensor electrode Y2, When the fourth sensor electrode Y4 adjacent to the third sensor electrode Y3 and the fifth sensor electrode Y5 adjacent to the fourth sensor electrode Y4 are arranged in this order, the touch driving circuit 12 2 A touch input to the first mutual capacitance sensor formed between the first sensor electrode Y1 and the second sensor electrode Y2 is obtained by applying the touch driving signal TXM to the second sensor electrode Y2. At the same time as sensing through (Y1), the second touch driving signal (TXM) is applied to the fifth sensor electrode (Y5) to provide a second sensor electrode (Y4) and the fifth sensor electrode (Y5) provided between the A touch input to the mutual capacitance sensor may be sensed through the fourth sensor electrode Y4. At this time, a ground voltage (GND) or a direct current voltage (DC) may be applied to the third sensor electrode Y3 to reduce distortion of the sensing signal. Here, the sensor electrode to which the second touch driving signal TXM is applied becomes the Tx electrode, and the sensor electrode that forms a mutual capacitance sensor adjacent to the Tx electrode and is directly sensed becomes the Rx electrode. In this embodiment, sensor electrodes for sensing a touch input to the mutual capacitance sensor are disposed as Rx-Tx-GND-Rx-Tx.

In this embodiment, the sensing unit 160 of FIG. 6 , which is responsible for sensing the sensor electrodes in row 1, is connected to the odd number sensor electrodes Y1, Y3, ..., Y23 connected to the odd number sensor wires among the sensor wires. An odd number sensing unit (AFE) for selectively sensing a touch input for, and selectively sensing a touch input for the even sensor electrodes (Y2, Y4, ..., Y22) connected to the good sensor wires among the sensor wires. It includes an excellent sensing unit (AFE) for In addition, the multiplexer 140 of FIG. 6 in charge of sensing the first row sensor electrodes selectively connects the first input terminal (-) of the nose sensing unit AFE to any one of the nose sensor wires, and also the nose sensor. Selectively connecting an odd multiplexer (MUXO) for applying the second touch driving signal (TXM) to the other one of the wires and a first input end (-) of the even sensing unit (AFE) to any one of the even sensor wires In addition, an even multiplexer MUXE for applying the second touch driving signal TXM to the other one of the even sensor lines is included. Here, the odd number sensing unit AFE and even number sensing unit AFE are operated simultaneously, and the odd number multiplexer MUXO and even number multiplexer MUXE are operated simultaneously.

In the mutual sensing mode as shown in FIGS. 13 and 14 , 26*23 (598) sensor electrodes are sensed through a total of 12 sensing operations. At the first sensing time (M1), the second touch driving signal TXM is simultaneously applied to the sensor electrodes Y2 and Y5, and the sensor electrodes Y1 and Y4 are simultaneously sensed in synchronization therewith. Also, at the second sensing time (M2), the second touch driving signal TXM is simultaneously applied to the sensor electrodes Y3 and Y6, and the sensor electrodes Y2 and Y5 are simultaneously sensed in synchronization therewith. Also, at the third sensing time (M3), the second touch driving signal TXM is simultaneously applied to the sensor electrodes Y4 and Y7, and the sensor electrodes Y3 and Y6 are simultaneously sensed in synchronization therewith. According to this principle, 12 sensing operations are performed.

15 to 17 show different sensing channel selection sequences of multiplexers in the mutual sensing mode and corresponding sensing target electrodes.

Referring to FIG. 15 , the touch driving circuit 12 of the present invention can simultaneously sense sensor electrodes in two rows spaced apart from each other in a mutual sensing mode. In other words, the sensor electrodes include a first sensor electrode Y1, a second sensor electrode Y2 adjacent to the first sensor electrode Y1, a third sensor electrode Y3 adjacent to the second sensor electrode Y2, When the fourth sensor electrode Y4 adjacent to the third sensor electrode Y3 is arranged in order, the touch driving circuit 12 applies the second touch driving signal TXM to the second sensor electrode Y2 to generate a second sensor electrode Y2. A touch input to the first mutual capacitance sensor formed between the first sensor electrode Y1 and the second sensor electrode Y2 is sensed through the first sensor electrode Y1 and at the same time, the second touch driving signal TXM is transmitted. A touch input to the second mutual capacitance sensor formed between the third sensor electrode Y3 and the fourth sensor electrode Y4 may be sensed through the fourth sensor electrode Y4 by applying the touch input to the third sensor electrode Y3. there is. Here, the sensor electrode to which the second touch driving signal TXM is applied becomes the Tx electrode, and the sensor electrode that forms a mutual capacitance sensor adjacent to the Tx electrode and is directly sensed becomes the Rx electrode. In this embodiment, sensor electrodes for sensing a touch input to the mutual capacitance sensor are disposed as Rx-Tx-Tx-Rx. This electrode arrangement is advantageous in suppressing charge loss due to voltage change between Tx and GDN and the resulting electric field, compared to that of FIG. 12 . In addition, in this electrode arrangement, since the Tx electrodes are disposed adjacent to each other, a change in voltage on the Tx electrode can be offset, thereby maximizing the change in capacitance of the mutual capacitance sensor.

In this embodiment, the sensing unit 160 of FIG. 6 , which is responsible for sensing the sensor electrodes in row 1, is connected to the odd number sensor electrodes Y1, Y3, ..., Y23 connected to the odd number sensor wires among the sensor wires. An odd number sensing unit (AFE) for selectively sensing a touch input for, and selectively sensing a touch input for the even sensor electrodes (Y2, Y4, ..., Y22) connected to the good sensor wires among the sensor wires. It includes an excellent sensing unit (AFE) for In addition, the multiplexer 140 of FIG. 6 in charge of sensing the first row sensor electrodes selectively connects the first input terminal (-) of the nose sensing unit AFE to any one of the nose sensor wires, and also the nose sensor. Selectively connecting an odd multiplexer (MUXO) for applying the second touch driving signal (TXM) to the other one of the wires and a first input end (-) of the even sensing unit (AFE) to any one of the even sensor wires In addition, an even multiplexer MUXE for applying the second touch driving signal TXM to the other one of the even sensor lines is included. Here, the odd number sensing unit AFE and even number sensing unit AFE are operated simultaneously, and the odd number multiplexer MUXO and even number multiplexer MUXE are operated simultaneously.

In the mutual sensing mode as shown in FIGS. 16 and 17 , 26*23 (598) sensor electrodes are sensed through a total of 12 sensing operations. At the first sensing time (M1), the second touch driving signal TXM is simultaneously applied to the sensor electrodes Y2 and Y3, and the sensor electrodes Y1 and Y4 are simultaneously sensed in synchronization therewith. Also, at the second sensing time (M2), the second touch driving signal TXM is simultaneously applied to the sensor electrodes Y3 and Y4, and the sensor electrodes Y2 and Y5 are simultaneously sensed in synchronization therewith. Also, at the third sensing time (M3), the second touch driving signal TXM is simultaneously applied to the sensor electrodes Y6 and Y7, and the sensor electrodes Y5 and Y8 are simultaneously sensed in synchronization therewith. According to this principle, 12 sensing operations are performed.

18 shows an example of alternately sensing parts of self-capacitance sensors and mutual-capacitance sensors within a touch period. 19 shows an example of alternately sensing all self-capacitance sensors and mutual-capacitance sensors within a touch period.

Referring to FIG. 18, the touch driving circuit 18 of the present invention alternates between the self-sensing mode (S1-Sn) and the mutual sensing mode (M1-Mn) in a first cycle within the touch period Tt to generate self-capacitance sensors. and mutual capacitance sensors may be partially sensed alternately. In the case of FIG. 18 , self-sensing and mutual sensing are continuously performed, which is advantageous in ensuring continuity of sensing data for each location. However, in the case of FIG. 18 , since a lot of switching time is required for a multiplexer for alternating self-sensing and mutual sensing, the sensing time may be long.

Referring to FIG. 19, the touch driving circuit 18 of the present invention alternates the self-sensing mode (S1-Sn) and the mutual sensing mode (M1-Mn) with a second period longer than the first period within the touch period Tt. Thus, both the self-capacitance sensors and the mutual-capacitance sensors can be sensed alternately. 19, since self-sensing is performed on all sensor electrodes and then mutual sensing is performed on all sensor electrodes, the switching time of the multiplexer for alternating self-sensing and mutual sensing is small and the sensing time is short. There are advantages. However, in the case of FIG. 19, it is disadvantageous compared to FIG. 18 in terms of securing continuity of sensing data for each location.

As described above, the touch sensing system of the present invention senses a touch input at each of the sensor electrodes using the self-capacitance sensors and also senses a touch input between the sensor electrodes using the mutual capacitance sensors so that the touch sensors are connected. It is possible to improve the resolution, sensing sensitivity and accuracy of the touch screen without increasing the number.

Through the above description, those skilled in the art will understand that various changes and modifications are possible without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims.

18: touch driving circuit 140: multiplexer
160: sensing unit 210: driving signal selection unit
220: reference signal selector

Claims (9)

a touch screen including self-capacitance sensors provided on each of the sensor electrodes, mutual capacitance sensors provided between adjacent sensor electrodes, and sensor wires connected to the sensor electrodes;
A touch that senses a touch input to the self-capacitance sensors according to a first touch driving signal in a first sensing mode and a touch input to the mutual capacitance sensors according to a second touch driving signal in a second sensing mode. A driving circuit is provided;
The touch driving circuit,
a sensing unit for sensing the touch input;
a multiplexer selectively connecting a first input terminal of the sensing unit to one of the sensor wires;
Applying the first touch driving signal to sensor wires not connected to the sensing unit in the first sensing mode, and applying the second touch driving signal to sensor wires connected to the sensing unit in the second sensing mode a drive signal selector;
A reference signal selection unit for applying the first touch driving signal to a second input terminal of the sensing unit in the first sensing mode and applying a reference voltage to a second input terminal of the sensing unit in the second sensing mode;
In the second sensing mode, touch sensing in which a base voltage or a DC voltage is applied to sensor wires other than the first sensor wire to which the second touch driving signal is applied and the second sensor wire connected to the first input terminal of the sensing unit. system. delete According to claim 1,
In the second sensing mode, a sensor electrode connected to the first sensor wire and a sensor electrode connected to the second sensor wire are adjacent to each other. a touch screen including self-capacitance sensors provided on each of the sensor electrodes, mutual capacitance sensors provided between adjacent sensor electrodes, and sensor wires connected to the sensor electrodes;
A touch that senses a touch input to the self-capacitance sensors according to a first touch driving signal in a first sensing mode and a touch input to the mutual capacitance sensors according to a second touch driving signal in a second sensing mode. A driving circuit is provided;
The touch driving circuit,
a sensing unit for sensing the touch input;
a multiplexer selectively connecting a first input terminal of the sensing unit to one of the sensor wires;
Applying the first touch driving signal to sensor wires not connected to the sensing unit in the first sensing mode, and applying the second touch driving signal to sensor wires connected to the sensing unit in the second sensing mode a drive signal selector;
A reference signal selection unit for applying the first touch driving signal to a second input terminal of the sensing unit in the first sensing mode and applying a reference voltage to a second input terminal of the sensing unit in the second sensing mode;
The sensing unit includes an odd sensing unit for selectively sensing a touch input to odd sensor electrodes connected to odd sensor wires among the sensor wires, and excellent sensor electrodes connected to excellent sensor wires among the sensor wires. Including an excellent sensing unit for selectively sensing a touch input to the
The multiplexer includes: an odd multiplexer selectively connecting a first input end of the odd number sensing unit to any one of the odd number sensor wires, and selectively connecting a first input end of the even number sensing unit to any one of the even number sensor wires Includes an even multiplexer;
The odd number sensing unit and the even number sensing unit are operated simultaneously, and the odd number multiplexer and the even number multiplexer are operated simultaneously. According to claim 4,
The touch driving circuit,
In the first sensing mode, the first touch driving signal is applied to the first sensor electrode and the second sensor electrode adjacent to each other to generate a touch input to the first self-capacitance sensor provided in the first sensor electrode. A touch sensing system that simultaneously senses through a first sensor electrode and senses a touch input to a second self-capacitance sensor provided in the second sensor electrode through the second sensor electrode. According to claim 4,
The sensor electrodes include a first sensor electrode, a second sensor electrode adjacent to the first sensor electrode, a third sensor electrode adjacent to the second sensor electrode, a fourth sensor electrode adjacent to the third sensor electrode, and the When the fifth sensor electrode is arranged in order adjacent to the fourth sensor electrode,
The touch driving circuit,
In the second sensing mode, a touch input to a first mutual capacitance sensor provided between the first sensor electrode and the second sensor electrode is obtained by applying the second touch driving signal to the second sensor electrode. At the same time as sensing through the electrode, the second touch driving signal is applied to the fifth sensor electrode to generate a touch input to the second mutual capacitance sensor provided between the fourth sensor electrode and the fifth sensor electrode. Sensing through the sensor electrode,
A touch sensing system in which a base voltage or a direct current voltage is applied to the third sensor electrode. According to claim 4,
The sensor electrodes are arranged in the order of a first sensor electrode, a second sensor electrode adjacent to the first sensor electrode, a third sensor electrode adjacent to the second sensor electrode, and a fourth sensor electrode adjacent to the third sensor electrode. when deployed,
The touch driving circuit,
In the second sensing mode, a touch input to a first mutual capacitance sensor provided between the first sensor electrode and the second sensor electrode is obtained by applying the second touch driving signal to the second sensor electrode. At the same time as sensing through the electrode, the second touch driving signal is applied to the third sensor electrode so that a touch input to the second mutual capacitance sensor provided between the third sensor electrode and the fourth sensor electrode is applied to the fourth sensor electrode. A touch sensing system that senses through sensor electrodes. According to claim 1,
The touch driving circuit,
The touch sensing system for alternately sensing the first sensing mode and the second sensing mode by parts of the self-capacitance sensors and the mutual capacitance sensors. According to claim 1,
The touch driving circuit,
A touch sensing system that alternately senses all of the self-capacitance sensors and the mutual-capacitance sensors in the first sensing mode and the second sensing mode.

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