KR20210046624A - Touch sensing system - Google Patents

Abstract

The present invention relates to a touch sensing system that divides and drives a touch screen using a plurality of touch sensing ICs and includes a touch screen, first and second dummy electrodes, first and second touch sensing ICs, and a microprocessor unit. The touch screen includes touch sensors formed by touch driving lines and touch sensing lines and includes a first sensing region and a second sensing region in which the touch sensing lines are divided. The first dummy electrode is disposed adjacent to the first sensing region, and the second dummy electrode is disposed adjacent to the second sensing region. The first touch sensing IC senses a touch input of the first sensing region using a signal received through the first touch sensing lines and the first dummy electrode disposed in the first sensing region. The first touch sensing IC senses a touch input of the second sensing region using a signal received through the second touch sensing lines and the second dummy electrode disposed in the second sensing region. The microprocessor unit calculates the signal sensed from the first touch sensing IC and the signal output from the second touch sensing IC to output touch coordinates. Accordingly, touch precision can be improved.

Description

Touch sensing system {TOUCH SENSING SYSTEM}

The present invention relates to a touch sensing system that divides and drives a touch screen using a plurality of touch sensing ICs.

Recently, various input devices such as a keyboard, a mouse, a trackball, a joystick, and a digitizer are used to construct an interface between a user and a home appliance or various information and communication devices. However, using the input device as described above causes inconvenience such as learning how to use and occupying space, making it difficult to increase the completeness of the product. Accordingly, the demand for an input device that is convenient and simple and capable of reducing malfunctions is increasing day by day. In accordance with such a request, a touch screen has been proposed in which a user directly touches or closes the screen with a hand or a pen while viewing a display device of a home appliance or various information communication devices to input information.

The touch screen is applied to a variety of display devices because it is simple, has few malfunctions, and can be input without using a separate input device, as well as the convenience that the user can quickly and easily operate through the contents displayed on the screen. have.

The touch screen is divided into an optical method and a capacitive method according to a method of sensing a touched part, and the capacitive method is further subdivided into a self capacitance type and a mutual capacitance type.

In the self-capacitive touch screen, a plurality of independent patterns are formed in a touch area of a panel and a change in capacitance of each independent pattern is measured to determine whether to touch.

The mutual capacitive touch screen is a matrix by intersecting X-axis electrode lines (eg, driving electrode lines) and Y-axis electrode lines (eg, sensing electrode lines) in the touch electrode formation region of the panel. Is formed, a driving pulse is applied to the X-axis electrode lines, and then touches by sensing a change in voltage appearing at the sensing nodes defined as the intersection of the X-axis electrode lines and the Y-axis electrode lines through the Y-axis electrode lines. It is a method of determining whether or not.

Hereinafter, a conventional mutual capacitance type touch screen will be described with reference to FIGS. 1 to 3. 1 is a diagram showing an example of connecting a plurality of touch sensing ICs to a touch screen, FIG. 2 is a diagram showing a differential amplifier connected to Rx channels of the touch sensing IC, and FIG. 1 This is a circuit diagram showing differential amplifiers connected to Rx channels of a touch sensing IC.

Referring to FIG. 1, a conventional mutual capacitance type touch screen TS includes driving electrode lines Tx1 to Tx4 and sensing electrode lines Rx1 to Rx8 crossing the driving electrode lines Tx1 to Tx4. , And touch sensors formed by the driving electrode lines Tx1 to Tx4 and the sensing electrode lines Rx1 to Rx8. Each of the touch sensors includes a mutual capacitance Cm. The touch sensing circuit supplies a driving signal to the driving electrode lines (Tx1 to Tx4) and receives the touch sensor signal through the sensing electrode lines (Rx1 to Rx8) in synchronization therewith to sense the amount of change in charge of the touch sensor, and the amount of change in charge. Is analyzed to determine whether or not a touch is input and its location.

In the case of the large-screen touch screen TSP, there are many driving electrode lines Tx1 to Tx4 and sensing electrode lines Rx1 to Rx8 of the touch screen TSP. The large-area touch screen TSP may be dividedly driven by being connected to a plurality of touch sensing integrated circuits (ICs) (IC#1, IC#2). A touch sensing circuit is integrated in each of the touch sensing ICs IC#1 and IC#2. The reception channels (hereinafter referred to as "Rx channels") of the first touch sensing IC IC#1 include first to fourth sensing electrode lines Rx1 to Rx4 formed on the left half of the touch screen TSP. Connected. The Rx channels of the second touch sensing IC IC#2 are connected to the fifth to eighth sensing electrode lines Rx1 to Rx8 formed on the right half of the touch screen TSP.

Differential amplifiers 11 to 14 may be connected to the Rx channels of the touch sensing ICs IC#1 and IC#2 as shown in FIGS. 2 and 3. The output terminals of each of the differential amplifiers 11 to 14 are connected to the inverting input terminal (-) via a capacitor (C). Each of the differential amplifiers 11 to 14 includes an i-th touch sensor signal input to the inverting input terminal (-) (i is a positive integer) and an i+1 touch sensor signal input to the non-inverting input terminal (+). The difference is amplified and the ith sensor signals S1 to S4 are output. Noise of a similar size may be applied to neighboring touch sensors. Accordingly, the differential amplifiers 11 to 14 remove noise by amplifying the difference between signals received through neighboring sensing electrode lines as shown in FIG. 3 and increase the signal component to increase the signal-to-noise ratio. Ratio: SNR) can be improved.

However, the prior art has a problem in that the signal-to-noise ratio (SNR) is low at the boundary between the touch sensing ICs IC#1 and IC#2. In order to increase the signal-to-noise ratio (SNR) using a differential amplifier, signals including noise of the same size must be input to both input terminals of the differential amplifier. A fourth sensing electrode line Rx4 is connected to the inverting input terminal (-) of the differential amplifier 14, and a preset dummy signal D0 is applied to the non-inverting input terminal (+). Accordingly, the output signal of the differential amplifier 14 includes an amplified signal component and a noise component. For this reason, the signal-to-noise ratio (SNR) for the touch sensors existing at the boundary between the left and right halves of the touch screen TSP is lower than that of other touch sensors. As a result, when the touch screen TSP is driven by a plurality of touch sensing ICs IC#1 and IC#2 as shown in FIG. 1, the touch input is determined in the middle part of the touch screen TSP. Is difficult.

US 8,350,824 B2 discloses a method of connecting two ICs to a large-screen touch screen (TSP) and obtaining touch sensor data (hereinafter referred to as “boundary data”) at the boundary between the ICs. The sensing method disclosed in U.S. Patent US 8,350,824 B2 proposes a method of low pass filtering the boundary data between ICs and neighboring data to obtain boundary data, and generating boundary data using the average of the results. I did. However, this sensing method requires a large amount of data computation and a long data processing time because the surrounding data of the boundary data must be compared and averaged to obtain the boundary data, and the accuracy of the data is low when the output deviation between ICs is large. .

The present invention is to provide a touch sensing system capable of improving touch precision by improving a signal-to-noise ratio at a boundary between touch sensing ICs when a plurality of touch sensing ICs are connected to a touch screen.

The touch sensing system according to the present invention includes a touch screen, first and second dummy electrodes, first and second touch sensing ICs, and a microprocessor unit. The touch screen includes touch sensors formed by touch driving lines and touch sensing lines, and includes a first sensing area and a second sensing area in which the touch sensing lines are divided and disposed. The first dummy electrode is disposed adjacent to the first sensing area, and the second dummy electrode is disposed adjacent to the second sensing area. The first touch sensing IC senses the touch input of the first sensing region using first touch sensing lines arranged in the first sensing region and a signal received through the first dummy electrode, and the first touch sensing IC is 2 A touch input of the second sensing region is sensed using a signal received through the second touch sensing lines and the second dummy electrode disposed in the sensing region. The microprocessor unit calculates a signal sensed from the first touch sensing IC and a signal output from the second touch sensing IC to output touch coordinates.

In the above configuration, each of the first and second dummy electrodes includes a dummy driving electrode and a dummy sensing electrode arranged to cross each other and insulated at the crossing portion. The same driving signal as the driving signal supplied to the touch driving line is supplied to the dummy driving electrode.

In addition, the first touch sensing IC includes a first differential amplifier that differentially amplifies and outputs signals supplied from odd-numbered touch sensing lines and even-numbered touch sensing lines, even-numbered touch sensing lines and odd-numbered touch sensing lines. And a second differential amplifier differentially amplifying and outputting signals supplied from and a third differential amplifier differentially amplifying signals supplied from the first dummy electrode and the touch sensing line of the first sensing region closest thereto. The second touch sensing IC includes a fourth differential amplifier differentially amplifying signals supplied from a second dummy electrode and a touch sensing line of the second sensing area closest thereto, an odd-numbered touch sensing line and an even-numbered touch sensing line And a fifth differential amplifier differentially amplifying and outputting signals supplied from and a sixth differential amplifier differentially amplifying and outputting signals supplied from an even-numbered touch sensing line and an odd-numbered touch sensing line.

In contrast, the first touch sensing IC is a 1-1 multiplexer having input channels through which signals supplied from an odd-numbered touch sensing line and signals supplied from a dummy sensing electrode of the first dummy electrode are input, and an even-numbered multiplexer. It may include a 1-2x multiplexer having an input channel through which signals supplied from the touch sensing line are input. The second touch sensing IC includes a 2-1 multiplexer having input channels to which signals supplied from an odd-numbered touch sensing line are input, and a signal supplied from a dummy sensing electrode of the first dummy electrode and an even-numbered touch sensing line. A 2-2 multiplexer having an input channel through which signals supplied from are input may be included.

In addition, the first touch sensing IC may further include a first differential amplifier for differentially amplifying and outputting a signal output from the 1-1 multiplexer and a signal output from the 1-2 multiplexer. In addition, the second touch sensing IC may further include a second differential amplifier for differentially amplifying and outputting a signal output from the 2-1 multiplexer and the signal output from the 2-2 multiplexer.

According to the touch sensing system according to the present invention, when a plurality of touch sensing ICs are connected to the touch screen and driven, the signal-to-noise ratio of signals received from the touch sensors at the boundary between the touch sensing ICs can be improved. An effect that can improve precision can be obtained.

1 is a schematic diagram showing an example of connecting a plurality of touch sensing ICs to a touch screen;
2 is a circuit diagram showing a differential amplifier connected to Rx channels of a touch sensing IC;
3 is a circuit diagram showing differential amplifiers connected to Rx channels of the first touch sensing IC shown in FIG. 1;
4 is a plan view schematically showing a touch sensing system according to an embodiment of the present invention;
5A is a block diagram showing a touch sensing system according to a first embodiment of the present invention;
5B is a plan view showing the dummy electrode shown in FIG. 5A;
6 is a block diagram showing a touch sensing system according to a second embodiment of the present invention;
7 is a block diagram schematically illustrating a display device to which a touch screen system according to exemplary embodiments is applied.

The touch sensing system of the present invention includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an organic light emitting diode display. It can be implemented based on flat panel displays such as Display, OLED), and electrophoresis (EPD). In the following embodiments, a liquid crystal display is described as an example of a flat panel display device to which the touch sensing system of the present invention is applied, but the present invention is not limited thereto and may be applied to other flat panel display devices.

The touch sensing system of the present invention may be implemented as a capacitive touch screen that senses a touch input through a plurality of capacitive sensors. The capacitive touch screen includes a plurality of touch sensors. Each of the touch sensors has a capacitance. The capacitance can be divided into self capacitance and mutual capacitance. The self-capacitance is formed along single-layer conductor wiring formed in one direction. Mutual capacitance is formed between two orthogonal conductor wires. In the following embodiments, a mutual capacitive touch screen is illustrated, but it should be noted that the touch sensing system of the present invention is not limited to the mutual capacitive touch screen.

Hereinafter, a driving signal wire for supplying a driving signal to a touch sensor from a touch screen will be described as a driving electrode line, and a sensing wire for transmitting a touch sensor signal to the touch sensing IC will be described as a sensing electrode line.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numbers throughout the specification mean substantially the same elements. In the following description, when 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, a detailed description thereof will be omitted.

First, a touch sensing system according to an embodiment of the present invention will be described with reference to FIGS. 4 to 5B. 4 is a plan view schematically showing a touch sensing system according to an embodiment of the present invention, FIG. 5A is a block diagram illustrating a touch sensing system according to a first embodiment of the present invention, and FIG. 5B is shown in FIG. 5A. It is a plan view showing the dummy electrode.

4 to 5B, the touch sensing system according to the first embodiment of the present invention includes a touch screen (TSP), a plurality of touch sensing ICs (IC#1, IC#2), and a microcontroller unit (MCU). Includes.

As shown in FIG. 5A, the touch screen TSP includes driving electrode lines Tx1 to Tx5, sensing electrode lines Rx1 to Rx8, driving electrode lines Tx1 to Tx5, and sensing electrodes arranged to cross each other. Touch sensors defined as intersection points of the lines Rx1 to Rx8 and dummy electrodes DE1 and DE2 are included.

The touch screen TSP includes a first sensing area 21 and a second sensing area 22. The first sensing area 21 may be a left half of the touch screen TSP, and the second sensing area 22 may be a right half of the touch screen TSP. In the touch screen TSP, the touch sensors and the sensing electrode lines Rx1 to Rx8 are included in one of the first sensing area 21 and the second sensing area 22.

The driving electrode lines Tx1 to Tx5 are arranged parallel to each other in a first direction (for example, in the x-axis direction), and a driving signal wiring for supplying electric charges to the touch sensors by applying a driving signal to each of the touch sensors. admit.

The sensing electrode lines Rx1 to Rx8 are arranged in parallel with each other in a second direction crossing the first direction (for example, in the y-axis direction), and are connected to the touch sensors to control the charge of the touch sensors. These are sensing wires that are supplied to (IC#1, IC#2).

The number and structure of driving electrode lines and sensing electrode lines formed in each of the first and second sensing regions 21 and 22 are not limited to the examples shown in the drawings for describing the exemplary embodiment of the present invention.

The driving electrode lines Tx1 to Tx5 and the sensing electrode lines Rx1 to Rx8 may be arranged in different layers with an insulating layer (or dielectric layer) therebetween so as not to contact each other at the intersections thereof.

Alternatively, the driving electrode lines Tx1 to Tx5 and the sensing electrode lines Rx1 to Rx8 may be arranged on the same layer. In this case, the driving electrode lines Tx1 to Tx5 or the sensing electrode lines Rx1 to Rx8 are separated at their intersections. The separated driving electrode lines or the separated sensing electrode lines may be connected to each other by forming a contact hole in the insulating layer and using a connection pattern. In this case, the connection pattern crosses the sensing electrode line or the driving electrode line that is not separated with the insulating layer therebetween.

The dummy electrodes DE1 and DE2 include a first dummy electrode DE1 and a second dummy electrode DE2. The first dummy electrode DE1 is disposed adjacent to the sensing electrode line Rx4 positioned at the innermost side of the first sensing region 21. The second dummy electrode DE2 is disposed adjacent to the sensing electrode line Rx5 positioned at the innermost side of the first sensing region 21. Each of the first dummy electrode DE1 and the second dummy electrode DE2 includes a dummy driving electrode DD and a dummy sensing electrode DS that are intersected and insulated from each other.

In the embodiment of the present invention shown in FIG. 5A, the first to fourth sensing electrode lines Rx1 to Rx4 are disposed in the first sensing region 21, and the fifth to eighth sensing electrode lines Rx5 to Rx8 is an example of being disposed in the second sensing area 22.

Meanwhile, the driving electrode lines Tx1 to Tx5 are shown and described as being shared in the first and second sensing regions 21 and 22, but may be separated for each touch sensing IC. A method of dividing the driving electrode lines for each touch sensing IC is proposed in Korean patent application 10-2012-0042655 (2012. 04. 24) and US patent application 13/869,738 (2013. 04. 24) filed by the applicant of the present application. It can be applied in the old way.

The plurality of touch sensing ICs include a first touch sensing IC (IC#1) to which a signal sensed by the first sensing region 21 is input through the sensing electrode lines Rx1 to Rx4 of the first group, and a second group. And a second touch sensing IC (IC#2) to which a signal sensed by the second sensing region 22 is input through the sensing electrode lines Rx5 to Rx8 of.

Specifically, the first touch sensing IC (IC#1) senses the amount of charge change of the touch sensor before and after the touch with respect to the touch sensors of the first sensing area 21 to determine whether a conductive material such as a finger is touched and its location. do. The first touch sensing IC (IC#1) supplies a driving signal to the driving electrode lines Tx1 to Tx5 and the first dummy electrode DE1 connected to its own Tx channels, and the first touch sensing IC (IC#1) supplies a driving signal in synchronization with the driving signal. The touch sensor signal is received through the group sensing electrode lines Rx1 to Rx4.

The second touch sensing IC (IC#2) senses the amount of change in charge of the touch sensor before and after the touch with respect to the touch sensors in the second sensing area 22 to determine whether a conductive material such as a finger is touched and its location. The second touch sensing IC (IC#2) supplies a driving signal to the driving electrode lines Tx1 to Tx5 connected to its own Tx channels and the second dummy electrode DE2, and in synchronization with the driving signal, the second touch sensing IC (IC#2) supplies a driving signal. The touch sensor signal is received through the group sensing electrode lines Rx5 to Rx6.

Each of the first and second touch sensing ICs IC#1 and IC#2 includes the driving electrode lines Tx1 to Tx5 and the dummy driving electrodes DE1 and DE2 of the first and second dummy electrodes DE1 and DE2. It includes a driving signal generator (not shown) for supplying a driving signal to DD), differential amplifiers 41 to 49, an analog to digital converter, and the like.

The driving signal supplied by the driving signal generator of the first and second touch sensing ICs IC#1 and IC#2 may be generated in various forms such as a square wave type pulse, a sine wave, and a triangular wave. The driving signal may be supplied two or more times to each of the driving electrode lines Tx1 to Tx5 and the dummy driving electrodes DD.

Each of the differential amplifiers 41 to 49 includes a capacitor C connected between an inverting input terminal (-) and an output terminal. The differential amplifiers 41 to 49 differentially amplify and output sensing signals supplied from the sensing electrode lines Rx1 to Rx8 and the dummy electrodes DE1 and DE2.

Specifically, the first differential amplifier 41 is a touch sensor signal received at the inverting input terminal (-) and the non-inverting input terminal (+) through the first sensing electrode line Rx1 and the second sensing electrode line Rx2. The difference between them is amplified and the amplified first touch amplified signal S1 is output. The second differential amplifier 42 amplifies the difference between the signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the second sensing electrode line Rx2 and the third Rx sensing electrode line Rx3. Thus, the amplified second touch amplified signal S2 is output. The third differential amplifier 43 amplifies the difference between the signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the third sensing electrode line Rx3 and the fourth sensing electrode line Rx4. The amplified third touch amplified signal S3 is output. The fourth differential amplifier 44 amplifies and amplifies the difference between signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the fourth sensing electrode line Rx4 and the first dummy electrode DE1. The fourth touch amplified signal S4 is output.

The fifth differential amplifier 45 amplifies and amplifies the difference between signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the second dummy electrode DE2 and the fifth sensing electrode line Rx5. The fifth touch amplified signal S5 is output. The sixth differential amplifier 46 amplifies the difference between the signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the fifth sensing electrode line Rx5 and the sixth sensing electrode line Rx6. The amplified sixth touch amplified signal S6 is output. The seventh differential amplifier 47 amplifies the difference between the signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the sixth sensing electrode line Rx6 and the seventh sensing electrode line Rx7. The amplified seventh touch amplified signal S7 is output. The eighth differential amplifier 48 amplifies the difference between the signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the seventh sensing electrode line Rx7 and the eighth sensing electrode line Rx8. The amplified seventh touch amplified signal S7 is output. The ninth differential amplifier 49 amplifies the difference between signals received at the inverting input terminal (-) and the non-inverting input terminal (+) through the eighth sensing electrode line (Rx8) and the dummy signal line (DΦ). The ninth touch amplified signal S9 is output.

Accordingly, each signal sensed through the first to eighth sensing signal lines Rx1 to Rx8 is referred to as a1 to a8, and a signal sensed through the first and second dummy electrodes DE1 and DE2 is referred to as d1. , d2, and the signal sensed through the dummy line (DΦ) as d3, inverting input terminals (-) and non-inverting input terminals (+) of the first to ninth differential amplifiers 41 to 49 Signals a1 and a2, a2 and a3, a3 and a4, a4 and d1, d2 and a5, a5 and a6, a6 and a7, a7 and a8, a8 and d3 are respectively input to. The output terminals of the first to ninth differential amplifiers 41 to 49 are touch amplified signals (S1=a1-a2, S2=a2-a3, S3=a3-a4, S4=a4-d1, S5=d2-a5). , S6=a5-a6, S7=a6-a7, S8=a7-a8, S9=a8-d3) respectively.

The first to ninth analog-to-digital converters AD1 to AD9 convert the touch amplified signals S1 to S9 supplied from the first to ninth differential amplifiers 41 to 49 into digital signals, respectively, and output them. In the first embodiment of the present invention, a configuration in which the first to ninth differential amplifiers 41 to 49 and the first to ninth analog-to-digital converters AD1 to AD9 are connected 1:1 has been described. When a multiplexer is inserted between the first to ninth differential amplifiers 41 to 49 and the analog-to-digital converter, the number of analog-to-digital converters can be reduced to correspond to the number of touch sensing ICs.

The MCU detects the touch position by calculating digital signals supplied from the first and second touch sensing ICs IC#1 and IC#2. That is, the MCU is a digital value obtained by differentially amplifying the sensing signals sensed from the first group of sensing electrode lines Rx1 to Rx4 and the first dummy electrode DE1 belonging to the first sensing region 21 and the second dummy. The amplified digital value of the sensing signal sensed from the second group of sensing electrode lines Rx5 to Rx8 belonging to the electrode DE2 and the second sensing region 22 is calculated. As a result, a digital value (S4'=a4-d1) obtained by outputting from the fourth differential amplifier 44 located adjacent to the boundary between the first sensing region 21 and the second sensing region 22 and the fourth differential amplifier When the digital value (S5'=d2-a5) output from (44) is added, a4-d1+d2-a5=a4-a5 becomes the boundary between the first sensing region 21 and the second sensing region 22 The touch sensing value at is obtained.

Therefore, according to the touch screen system according to the first embodiment of the present invention, when two or more touch sensing ICs are connected to the touch screen, it is possible to improve the signal-to-noise ratio (SNR) at the boundary between the ICs, so that accurate touch sensing You can get the effect of getting the data.

Next, a touch screen system according to a second embodiment of the present invention will be described with reference to FIG. 6. 6 is a block diagram showing a touch sensing system according to a second embodiment of the present invention.

6, a touch sensing system according to a second embodiment of the present invention includes a touch screen (TSP), a plurality of touch sensing ICs (IC#1, IC#2), and a microcontroller unit (MCU). .

The touch sensing system according to the second embodiment of the present invention is the same as the touch sensing system according to the first embodiment except for the touch sensing ICs IC#1 and IC#2. Accordingly, in the following description, descriptions of components that are the same as those of the first embodiment will be omitted in order to avoid redundant descriptions.

The touch sensing ICs of the touch sensing system according to the second embodiment of the present invention are the first touch sensing in which a signal sensed by the first sensing region 21 is input through the sensing electrode lines Rx1 to Rx4 of the first group. An IC (IC#1) and a second touch sensing IC (IC#2) to which a signal sensed by the second sensing region 22 is input through the sensing electrode lines Rx5 to Rx8 of the second group. .

Specifically, the first touch sensing IC (IC#1) senses the amount of charge change of the touch sensor before and after the touch with respect to the touch sensors of the first sensing area 21 to determine whether a conductive material such as a finger is touched and its location. do. The first touch sensing IC (IC#1) supplies a driving signal to the driving electrode lines Tx1 to Tx5 and the first dummy electrode DE1 connected to its own Tx channels, and the first touch sensing IC (IC#1) supplies a driving signal in synchronization with the driving signal. The touch sensor signal is received through the group sensing electrode lines Rx1 to Rx4.

The second touch sensing IC (IC#2) senses the amount of change in charge of the touch sensor before and after the touch with respect to the touch sensors in the second sensing area 22 to determine whether a conductive material such as a finger is touched and its location. The second touch sensing IC (IC#2) supplies a driving signal to the driving electrode lines Tx1 to Tx5 connected to its own Tx channels and the second dummy electrode DE2, and in synchronization with the driving signal, the second touch sensing IC (IC#2) supplies a driving signal. The touch sensor signal is received through the group sensing electrode lines Rx5 to Rx6.

Each of the first and second touch sensing ICs IC#1 and IC#2 includes a driving signal generator (not shown) that supplies a driving signal to the driving electrode lines Tx1 to Tx5, and first and second Multiplexers (MUX1a, MUX1b; MUX2a, MUX2b), differential amplifiers (51; 52), analog to digital converter (Analog to Digital Converter) (AD1; AD2), and the like.

The driving signal supplied by the driving signal generator of the first and second touch sensing ICs IC#1 and IC#2 may be generated in various forms such as a square wave type pulse, a sine wave, and a triangular wave. The driving signal may be supplied two or more times to each of the driving electrode lines Tx1 to Tx5.

Among the first multiplexers MUX1a and MUX1b, the 1-1 multiplexer MUX1a has input terminals to which odd-numbered sensing electrode lines Rx1 and Rx3 belonging to the first sensing region 21 are connected, and the first 2 The multiplexer MUX1b has input terminals to which the even-numbered sensing electrode lines Rx2 and Rx4 belonging to the first sensing region 21 and the first dummy electrode DE1 are connected.

Of the second multiplexers MUX2a and MUX2b, the 2-1 multiplexer MUX2a is connected to the first dummy electrode DE1 and the odd-numbered sensing electrode lines Rx5 and Rx7 belonging to the second sensing region 22 The 2-2 multiplexer MUX2b has input terminals to which even-numbered sensing electrode lines Rx6 and Rx8 belonging to the second sensing region 22 are connected to the dummy line DΦ.

That is, the odd-numbered sensing electrode lines Rx1, Rx3, Rx5, and Rx7 of the first and second sensing regions 21 and 22 are connected to the 1-1 and 2-1 multiplexers MUX1a and MUX2a, , Even-numbered sensing electrode lines Rx2, Rx4, Rx6, and Rx8 and the first and second dummy electrodes DE1 and DE2 are connected to the 1-2 and 2-2 multiplexers MUX1b and MUX2b.

Among the differential amplifiers 51 and 52, the first differential amplifier 51 is the signal a1 received from the odd-numbered first sensing electrode line Rx1 through the 1-1 multiplexer MUX1a and the even-numbered 2 The difference a1-a2 between the signal a2 received through the 1-2 multiplexer MUX1b from the sensing electrode line Rx2 is amplified. In addition, the first differential amplifier 51 includes a signal a2 received from the even-numbered second sensing electrode line Rx2 through the 1-2x multiplexer MUX1b and the odd-numbered third sensing electrode line Rx3. The difference a2-a3 between the signal a3 received through the 1-1 multiplexer MUX1a is amplified. The first differential amplifier 51 is a signal a3 received from the odd-numbered third sensing electrode line Rx3 through the 1-1 multiplexer MUX1a and the even-numbered fourth sensing electrode line Rx4. The difference (a3-a4) of the signal (a4) received at the non-inverting input terminal (+) through the 1-2 multiplexer (MUX1b) is amplified. In addition, the first differential amplifier 51 receives the signal a4 received from the even-numbered fourth sensing electrode line Rx4 through the 1-2 multiplexer MUX1b and the first dummy electrode DE1. -1 Amplifies the difference (a4-d1) of the signal d1 received through the multiplexer (MUX1a).

Among the differential amplifiers 51 and 52, the second differential amplifier 52 includes a signal d2 received from the second dummy electrode DM2 through the 2-2 multiplexer MUX2b and an odd fifth sensing electrode line. The difference (d2-a5) of the signal (a5) received through the 2-1 multiplexer (MUX2b) from (Rx5) is amplified. In addition, the second differential amplifier 52 includes a signal a5 received from the odd-numbered fifth sensing electrode line Rx5 through the 2-1 multiplexer MUX2a and the even-numbered sixth sensing electrode line Rx6. The difference (a5-a6) of the signal (a6) received from the non-inverting input terminal (+) through the 2-2 multiplexer (MUX2b) is amplified. The second differential amplifier 52 is a signal a6 received from the even-numbered sixth sensing electrode line Rx6 through the 2-2 multiplexer MUX2a and the odd-numbered seventh sensing electrode line Rx7. 2-1 Amplifies the difference (a6-a7) of the signal (a7) received through the multiplexer (MUX2a). The second differential amplifier 52 is a signal a7 received from the odd-numbered seventh sensing electrode line Rx7 through the 2-1 multiplexer MUX2a and the even-numbered eighth sensing electrode line Rx8. 2-2 Amplifies the difference (a7-a8) of the signal (a8) received at the non-inverting input terminal (+) through the multiplexer (MUX2b). The second differential amplifier 52 includes a signal a8 received from the even-numbered eighth sensing electrode line Rx8 through the 2-2 multiplexer MUX2b and the 2-1 multiplexer from the dummy signal line DΦ. The difference a8-d3 of the signal d3 input through MUX2a) is amplified.

Accordingly, the first differential amplifier 51 outputs the touch amplified signals (S1=a1-a2, S2=a2-a3, S3=a3-a4, S4=a4-d1), and the second differential amplifier 52 Outputs the touch amplified signals (S5=d2-a5, S6=a5-a6, S7=a6-a7, S8=a7-a8, S9=a8-d3).

The first analog-to-digital converter AD1 among the first and second analog-to-digital converters AD1 and AD2 converts the touch amplified signals S1 to S4 supplied from the first differential amplifier 51 into digital signals, respectively. Print it out. The second analog-to-digital converter AD2 converts each of the touch amplified signals S5 to S9 supplied from the second differential amplifier 52 into digital signals and outputs them.

The MCU detects the touch position by calculating digital signals supplied from the first and second touch sensing ICs IC#1 and IC#2. That is, the MCU is a digital value obtained by differentially amplifying the sensing signals sensed from the first group of sensing electrode lines Rx1 to Rx4 and the first dummy electrode DE1 belonging to the first sensing region 21 and the second dummy. The amplified digital value of the sensing signal sensed from the second group of sensing electrode lines Rx5 to Rx8 belonging to the electrode DE2 and the second sensing region 22 is calculated. As a result, a digital value (S4'=a4-d1) obtained by outputting from the fourth differential amplifier 44 located adjacent to the boundary between the first sensing region 21 and the second sensing region 22 and the fourth differential amplifier When the digital value (S5'=d2-a5) output from (44) is added, a4-d1+d2-a5=a4-a5 becomes the boundary between the first sensing region 21 and the second sensing region 22 The touch sensing value at is obtained.

Therefore, according to the touch screen system according to the second embodiment of the present invention, when two or more touch sensing ICs are connected to the touch screen, it is possible to improve the signal-to-noise ratio (SNR) at the boundary between the ICs. You can get the effect of getting the data.

Next, a display device to which the touch screen system according to the first and second embodiments of the present invention is applied will be described with reference to FIG. 7. 7 is a schematic block diagram of a display device to which the following touch screen system is applied. 7 illustrates a case where the display device is a liquid crystal display device as an example, but the present invention is not limited thereto, and a flat panel such as a field emission display device, a plasma display panel, an organic light emitting diode display device, an electrophoretic display device, etc. It can be applied to display devices.

Referring to FIG. 7, a display device to which a touch screen system according to an embodiment of the present invention is applied is a touch screen system including a touch screen (TSP), touch sensing ICs (IC#1, IC#2), and an MCU. And, a display panel DIS, a display driving circuit, a timing controller 16, a host system 18, and the like.

The display panel DIS includes a liquid crystal layer formed between two substrates. The pixel array of the display panel DIS includes pixels formed in a pixel area defined by data lines (D1 to Dm, m is a positive integer) and gate lines (G1 to Gn, n is a positive integer). . Each of the pixels is connected to TFTs (Thin Film Transistor) formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode charging the data voltage, and a pixel electrode. It includes a storage capacitor (Cst) for maintaining the voltage.

A black matrix, a color filter, and the like are formed on the upper substrate of the display panel DIS. The lower substrate of the display panel DIS may be implemented in a color filter on TFT (COT) structure. In this case, the black matrix and the color filter may be formed on the lower substrate of the display panel DIS. The common electrode to which the common voltage Vcom is supplied may be formed on the upper or 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 is formed between the upper substrate and the lower substrate of the display panel DIS to maintain a cell gap of the liquid crystal cell.

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 scan 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 digital video data RGB input from the timing controller 16 into an analog positive/negative 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 scan 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 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 18. In response, the operation timing of the data driving circuit 12 and the scan driving circuit 14 is synchronized. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (Gate Output Enable, 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 18 may be implemented as any one of a television system, a set-top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, and a phone system. The host system 18 converts the digital video data RGB of an input image into a format suitable for display on the display panel DIS, including a system on chip (SoC) with a built-in scaler. The host system 18 transmits timing signals Vsync, Hsync, DE, and MCLK together with the digital video data to the timing controller 16. In addition, the host system 18 executes an application program linked with coordinate information (XY) of the touch report input from the touch screen driving circuit.

It will be appreciated by those skilled in the art through the above description that various changes and modifications can be made without departing from the technical idea of the present invention.

In the touch sensing system according to the embodiments of the present invention, the number of touch sensing ICs, driving electrode lines, and sensing electrode lines is described as a specific number, but this is for convenience of description and the present invention is not limited thereto. You should pay attention to. In particular, more touch sensing ICs may be used depending on the size or resolution of the touch screen (TSP) as the number of touch sensing ICs.

In addition, in the detailed description of the present invention, a case where the touch screen system according to the embodiments of the present invention is applied to a liquid crystal display has been described as an example, but it is obvious that it may be applied to other flat panel displays.

In addition, the touch screen system of the present invention may be separately attached to a display device, formed directly on an upper substrate of the display device, or applied in an in-cell method using a common electrode of the display device.

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

12: data driving circuit 14: scan driving circuit
16: timing controller 18: host system
41~49, 51~52: differential amplifier AD1~AD8: analog to digital converter
DIS: display panel DE1, DE2: dummy electrode
IC#1, IC#2: touch sensing IC TSP: touch screen
Tx1 to Tx5: driving electrode line Rx1 to Rx8: sensing electrode line

Claims (5)

A touch screen including touch sensors formed by touch driving lines and touch sensing lines, and including a first sensing area and a second sensing area in which the touch sensing lines are divided and disposed;
A single first dummy electrode disposed adjacent to a boundary between the first and second sensing regions, and a single second dummy electrode disposed adjacent to a boundary between the first and second sensing regions;
A first touch sensing IC configured to sense a touch input of the first sensing region using first touch sensing lines disposed in the first sensing region and a signal received through a first dummy electrode;
A second touch sensing IC configured to sense a touch input of the second sensing region by using signals received through second touch sensing lines and a second dummy electrode disposed in the second sensing region; And
A microprocessor unit that calculates a signal sensed from the first touch sensing IC and a signal output from the second touch sensing IC to output touch coordinates,
Each of the first and second dummy electrodes,
It is arranged to cross each other and includes a dummy driving electrode and a dummy sensing electrode insulated at the intersection,
A driving signal identical to a driving signal supplied to the touch driving line is supplied to the dummy driving electrode from each of the first touch sensing IC and the second touch sensing IC, and the sensing value of the dummy sensing electrode is the first touch sensing Touch sensing system, characterized in that supplied to each of the IC and the second touch sensing IC.
The method of claim 1,
The first dummy electrode is located inside the first touch sensing IC at the boundary between the first and second sensing regions,
The second dummy electrode is located inside the second touch sensing IC at a boundary between the first and second sensing regions.
The method of claim 1,
The first touch sensing IC,
A first differential amplifier differentially amplifying and outputting signals supplied from odd-numbered touch sensing lines and even-numbered touch sensing lines;
A second differential amplifier differentially amplifying and outputting signals supplied from an even-numbered touch sensing line and an odd-numbered touch sensing line; And
And a third differential amplifier differentially amplifying signals supplied from the first dummy electrode and the touch sensing line of the first sensing region closest thereto,
The second touch sensing IC,
A fourth differential amplifier differentially amplifying signals supplied from the second dummy electrode and the touch sensing line of the second sensing region closest thereto;
A fifth differential amplifier for differentially amplifying and outputting signals supplied from odd-numbered touch sensing lines and even-numbered touch sensing lines; And
A touch sensing system comprising a sixth differential amplifier for differentially amplifying and outputting signals supplied from an even-numbered touch sensing line and an odd-numbered touch sensing line.
The method of claim 1,
The first touch sensing IC,
A 1-1 multiplexer having input channels through which signals supplied from an odd-numbered touch sensing line and signals supplied from a dummy sensing electrode of the first dummy electrode are input; And
A 1-2 multiplexer having an input channel through which signals supplied from an even-numbered touch sensing line are input,
The second touch sensing IC,
A 2-1 multiplexer having input channels to which signals supplied from odd-numbered touch sensing lines are input; And
And a 2-2 multiplexer having an input channel through which signals supplied from a dummy sensing electrode of the first dummy electrode and signals supplied from an even-numbered touch sensing line are input.
The method of claim 4,
The first touch sensing IC further includes a first differential amplifier differentially amplifying and outputting a signal output from the 1-1 multiplexer and a signal output from the 1-2 multiplexer,
The second touch sensing IC further comprises a second differential amplifier differentially amplifying and outputting a signal output from the 2-1 multiplexer and a signal output from the 2-2 multiplexer. .

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