WO2013183926A1

WO2013183926A1 - Touch detection apparatus having function for controlling parasitic capacitance, and touch detection method

Info

Publication number: WO2013183926A1
Application number: PCT/KR2013/004939
Authority: WO
Inventors: 안병식
Original assignee: 주식회사 아이피시티
Priority date: 2012-06-04
Filing date: 2013-06-04
Publication date: 2013-12-12

Abstract

According to one embodiment of the present invention, a touch detection apparatus for a touch panel, including a plurality of sensor pads and signal wires connected to the plurality of sensor pads, respectively, is provided. The touch detection apparatus comprises a parasitic capacitance control unit for controlling the parasitic capacitance generated between a specific sensor pad which is to be an object of touch detection from among the plurality of sensor pads and another adjacent sensor pad. The parasitic capacitance control unit enables the output voltage of the specific sensor pad to be applied to another sensor pad connected to the signal wire that is adjacent to the signal wire of the specific sensor pad.

Description

Touch detection device and method having parasitic capacitance control function

The present invention relates to a device for detecting a touch, and more particularly, to a touch detection device for attenuating parasitic capacitance by applying an output terminal voltage of a sensor pad for detecting a touch to another adjacent sensor pad.

The touch screen panel is a device for inputting a user's command by touching a character or a figure displayed on a screen of the image display device with a human finger or other contact means, and is attached to and used on the image display device. The touch screen panel converts a contact position touched by a human finger or the like into an electrical signal, and the converted electrical signal is used as an input signal.

As a method of implementing a touch screen panel, a resistive film method, a light sensing method, and a capacitive method are known. The capacitive touch panel converts a contact position into an electrical signal by detecting a change in capacitance that a conductive sensing pattern forms with other surrounding sensing patterns or ground electrodes when a human hand or an object comes in contact.

1 is an exploded plan view of an example of a capacitive touch screen panel according to the related art.

Referring to FIG. 1, the touch screen panel 10 may include a first sensor pattern layer 13, a first insulating layer 14, and a second sensor pattern layer sequentially formed on the transparent substrate 12 and the transparent substrate 12. 15) and the second insulating film layer 16 and the metal wiring 17. As shown in FIG.

The first sensor pattern layer 13 may be connected along the transverse direction on the transparent substrate 12 and may be connected to the metal lines 17 in units of rows.

The second sensor pattern layer 15 may be connected along the column direction on the first insulating layer 14, and are alternately disposed with the first sensor pattern layer 13 so as not to overlap the first sensor pattern layer 13. . In addition, the second sensor pattern layer 15 is connected to the metal wires 17 in units of columns.

When a human finger or a contact means contacts the touch screen panel 10, a change in capacitance according to a contact position is transmitted to the driving circuit through the first and second

sensor pattern layers

13 and 15 and the metal wire 17. do. As the change in capacitance thus transferred is converted into an electrical signal, the contact position is identified.

However, the touch screen panel 10 must separately include a pattern made of a transparent conductive material such as indium tin oxide (ITO) on each of the

sensor pattern layers

13 and 15, and between the

sensor pattern layers

13 and 15. Since the insulating film layer 14 must be provided, the thickness increases.

In addition, since touch detection is possible only by accumulating a small change in capacitance generated by touch several times, it is necessary to detect a change in capacitance at a high frequency. In addition, in order to sufficiently accumulate the change in capacitance within a predetermined time, metal wiring for maintaining a low resistance is required, which causes a thick bezel on the edge of the touch screen and generates an additional mask process.

In order to solve this problem, a touch detection apparatus as shown in FIG. 2 has been proposed.

The touch detection device illustrated in FIG. 2 includes a touch panel 20, a driving device 30, and a circuit board 40 connecting the two.

The touch panel 20 includes a plurality of sensor pads 22 formed on the substrate 21 and arranged in a polygonal matrix form and connected to the sensor pads 22.

Each signal wire 23 has one end connected to the sensor pad 22 and the other end extending to the lower edge of the substrate 21. The sensor pad 22 and the signal wire 23 may be patterned on the cover glass 50.

The driving device 30 sequentially selects the plurality of sensor pads 22 one by one to measure the capacitance of the corresponding sensor pads 22, and detects whether or not a touch occurs.

Since the plurality of sensor pads 22 are formed of a conductor, and the distances between the respective sensor pads 22 are very close, parasitic capacitance may exist. Parasitic capacitances adversely affect the detection of touch occurrence.

Accordingly, there is a need for a technique for minimizing such parasitic capacitance to prevent an error in detecting whether a touch occurs.

In the touch detection device including a plurality of sensor pads, the present invention is to control the parasitic capacitance due to the relationship between the sensor pads so that the sensitivity of touch detection is improved.

According to an embodiment of the present invention for achieving the above object, in the touch detection device of the touch panel including a plurality of sensor pads and signal wires connected to each of the plurality of sensor pads, touch of the plurality of sensor pads; And a parasitic capacitance control unit for controlling parasitic capacitance generated between a specific sensor pad to be detected and another adjacent sensor pad, wherein the parasitic capacitance control unit has an output terminal voltage of the specific sensor pad. A touch detection device is provided, which is applied to another sensor pad connected with a signal wire adjacent to a signal wire of a.

The parasitic capacitance controller may allow an output terminal voltage of the specific sensor pad to be applied to the other sensor pad at the time of detecting the specific sensor pad.

The parasitic capacitance controller may include a buffer, an input terminal of the buffer may be connected to an output terminal of the specific sensor pad, and an output terminal of the buffer may be connected to the other sensor pad, respectively.

The parasitic capacitance controller may allow one of the output terminal voltages of the specific sensor pad detected in the first frame and the second frame to be selectively applied to the other sensor pad in the second frame.

The parasitic capacitance controller includes a buffer and a multiplexer, an input end of the buffer is connected to an output end of the specific sensor pad, an output end of the buffer is connected to an input end of the multiplexer, and an output end of the multiplexer is the other sensor. Can be connected to the pads respectively.

The parasitic capacitance controller may select one of output terminal voltages of the specific sensor pad detected in the first frame and the second frame and apply the voltage to the other sensor pad, respectively.

When the first frame is the first frame, the parasitic capacitance controller may allow an output terminal voltage of the specific sensor pad to be applied to the other sensor pad in the first frame.

When the output terminal voltage of the specific sensor pad detected in the second frame is higher than a reference value for touch detection, the parasitic capacitance controller applies the output terminal voltage of the specific sensor pad to the other sensor pad in the second frame. You can do that.

The plurality of sensor pads may be disposed in a row and column direction, and a dummy line may be formed between the columns and columns to suppress parasitic capacitance generation due to a relationship between sensor pads belonging to adjacent columns.

The plurality of sensor pads may have a larger area as they are farther from the driving device for driving the sensor pads.

Meanwhile, according to another embodiment of the present invention, in the touch detection method of a touch panel including a plurality of sensor pads and signal wires connected to each of the plurality of sensor pads, the touch detection of the plurality of sensor pads may be performed. Controlling parasitic capacitance by applying an output terminal voltage of a specific sensor pad to another sensor pad connected to a signal wire adjacent to a signal wire of the specific sensor pad; And detecting whether a touch is made based on a difference in an output terminal voltage change of the specific sensor pad, wherein the attenuation step includes outputting a signal of the specific sensor pad at a time when the specific sensor pad is detected. A touch detection method is provided, which is applied to another sensor pad having signal wiring adjacent to the wiring.

The parasitic capacitance control step may include applying an output terminal voltage of the specific sensor pad to the other sensor pad at the time of detecting the specific sensor pad.

The parasitic capacitance control step may include selectively applying one of an output terminal voltage of the specific sensor pad detected in the first frame and the second frame to the other sensor pad in the second frame.

The parasitic capacitance control step may include applying an output terminal voltage of the specific sensor pad to the other sensor pad in the first frame when the first frame is the first frame.

In the parasitic capacitance control step, when the output terminal voltage of the specific sensor pad detected in the second frame is higher than the reference value for the touch detection, the output terminal voltage of the specific sensor pad is changed to the other sensor pad in the second frame. And may be allowed to be applied.

According to an embodiment of the present invention, in the touch detection device including a plurality of sensor pads, the parasitic capacitance may be attenuated by applying the output terminal voltage of the sensor pad to be detected to another adjacent sensor pad, and thus touch sensitivity. Can be improved.

In addition, according to an embodiment of the present invention, in the touch detection device including a plurality of sensor pads, the output terminal voltage of the sensor pad which is the detection target detected in the first frame is applied to another sensor pad during touch detection in the second frame. By doing so, the parasitic capacitance can be adjusted, whereby the touch sensitivity can be improved.

Meanwhile, according to the exemplary embodiment of the present invention, in the touch detection apparatus including the plurality of sensor pads, the parasitic capacitance may be further reduced by forming a dummy line between the rows of the sensor pads.

The effects of the present invention are not limited to the above-described effects, but should be understood to include all the effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

2 is an exploded plan view of a conventional touch detection apparatus.

3 is a diagram illustrating a structure of a touch detection apparatus according to an embodiment of the present invention.

4 is a circuit diagram illustrating a touch detector according to an embodiment of the present invention.

5 is an exemplary waveform diagram of a touch detector according to an embodiment of the present invention.

6 illustrates a touch detection device according to an embodiment of the present invention.

7 illustrates n sensor pads belonging to one column.

8 is a diagram illustrating an example of arrangement of sensor pads and signal wires.

9 is a simplified circuit diagram of a touch detection apparatus according to an embodiment of the present invention.

10 is a diagram illustrating a touch detection device according to another embodiment of the present invention.

11 is a diagram illustrating n sensor pads belonging to one column.

12 is a diagram illustrating a parasitic capacitance controller of a touch detection apparatus according to another embodiment of the present invention.

13 is a simplified circuit diagram of a touch detection apparatus according to another embodiment of the present invention.

14 is a diagram illustrating an example of a dummy line formed according to an embodiment of the present invention.

15 is a diagram illustrating a configuration of a touch detection apparatus according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, it includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

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

Embodiments of the present invention relate to a touch detection scheme that improves touch sensitivity by adjusting parasitic capacitance.

Referring to FIG. 3, the touch detection apparatus includes a touch panel 100 and a driving device 200.

The touch panel 100 includes a plurality of sensor pads 110 and a plurality of signal wires 120 connected to the sensor pads 110.

For example, the plurality of sensor pads 110 may be rectangular or rhombic, but may be different from each other, or may be polygonal in a uniform shape. The sensor pads 110 may be arranged in a matrix form of adjacent polygons.

The driving device 200 may include a touch detector 210, a touch information processor 220, a memory 230, a controller 240, and the like, and may be implemented as one or more integrated circuit (IC) chips.

The touch detector 210, the touch information processor 220, the memory 230, and the controller 240 may be separated from each other, or two or more components may be integrated and implemented.

The touch detector 210 may include a plurality of switches and a plurality of capacitors connected to the sensor pad 110 and the signal wire 120, and drive circuits for touch detection by receiving a signal from the controller 240. The voltage corresponding to the detection result is output. In addition, the touch detector 210 may include an amplifier and an analog-to-digital converter, and may convert, amplify, or digitize the difference in the voltage change of the sensor pad 110 into the memory 230.

The touch information processor 220 processes the digital voltage stored in the memory 230 to generate necessary information such as whether or not it is touched, a touch area, and touch coordinates.

The memory 230 stores digital voltages and predetermined data used for touch detection, area calculation, and touch coordinate calculation or data received in real time based on the difference in the voltage change detected by the touch detector 210.

The controller 240 may control the touch detector 210 and the touch information processor 220, may include a micro control unit (MCU), and perform predetermined signal processing through firmware.

An operation of the touch panel and the touch detector shown in FIG. 3 will be described in detail with reference to FIGS. 4 and 5.

4 is a circuit diagram illustrating a touch detector according to an embodiment of the present invention, and FIG. 5 is an exemplary waveform diagram of a touch detector according to an embodiment of the present invention.

Referring to FIG. 4, the touch detector 210 is connected to the sensor pad 110 through a signal wire 120, and performs a switching operation 211, a parasitic capacitor Cp, a driving capacitor Cdrv, The common voltage capacitor Cvcom and the level shift detector 212 are included.

The transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, the common voltage capacitor Cvcom, and the level shift detection unit 212 may be grouped one per sensor pad 110 and the signal wire 120. The sensor pad 110, the signal wire 120, the transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, and the common voltage capacitor Cvcom are collectively referred to as a "touch sensing unit". . The touch sensing unit is a concept including a case where each component is electrically connected by a multiplexer.

Meanwhile, in the embodiment of the present invention, an electrical characteristic or data value when no touch occurs is referred to as a "non-touch reference value".

For convenience, the same reference numerals are used for capacitors and their capacitances.

The transistor 211 is, for example, a field effect transistor, in which a control signal Vg is applied to a gate, a charging signal Vb is applied to a source, and a drain is applied. ) May be connected to the signal wire 120. Of course, the source may be connected to the signal line 120 and the charging signal Vb may be applied to the drain. The control signal Vg and the charging signal Vb may be controlled by the controller 240, and other devices capable of performing a switching operation may be used instead of the transistor 211.

The parasitic capacitance Cp refers to the capacitance accompanying the sensor pad 110 and is a kind of parasitic capacitance formed by the sensor pad 110, the signal wire 120, and the like. The parasitic capacitance Cp may include any parasitic capacitance generated by the touch detector 210, the touch panel, and the image display device.

The common voltage capacitance Cvcom is a capacitance formed between the common electrode (not shown) and the touch panel 100 of the display device when the touch panel 100 is mounted on a display device (not shown) such as an LCD. to be. A common voltage Vcom such as a square wave is applied to the common electrode by the display device. Meanwhile, the common voltage capacitance Cvcom may also be included in the parasitic capacitance Cp as a parasitic capacitance. Hereinafter, unless otherwise mentioned, the common voltage capacitance Cvcom may be a parasitic capacitance ( It demonstrates as included in Cp).

The driving capacitance Cdrv is a capacitance formed in a path for supplying an alternating voltage Vdrv alternately at a predetermined frequency for each sensor pad 110. The alternating voltage Vdrv applied to the driving capacitor Cdrv is preferably a square wave signal. The alternating voltage Vdrv may be a clock signal having the same duty ratio, but different duty ratios. The alternating voltage Vdrv may be provided by a separate alternating voltage generating means, but may also use the common voltage Vcom.

Meanwhile, in FIG. 4, the touch capacitance Ct represents the capacitance formed between the sensor pad 110 and a touch input tool such as a user's finger when the user touches the sensor pad 110.

Referring to FIG. 5, the charging signal Vb and the control signal Vg are applied to the source and the gate of the transistor 211, respectively.

First, a case in which a touch input tool is not touched on the sensor pad 110 will be described. After the charge signal Vb rises to 5V, for example, when the control signal Vg applied to the gate of the transistor 211 rises from the low voltage VL to the high voltage VH, the transistor 211 is turned on and the charging section is turned on. (T1) starts. Accordingly, the sensor pad 110 is charged with the charging signal Vb of 5V, and the output voltage Vo becomes the charging voltage Vb. The parasitic capacitor Cp, the driving capacitor Cdrv, and the common voltage capacitor Cvcom are also charged with the charge voltage Vb. In the charging period T1, since the transistor 211 is turned on, the alternating voltage Vdrv does not affect the output voltage Vo.

Next, when the sensing period T2 starts while the control signal Vg goes from the high voltage VH to the low voltage VL, the transistor 211 is turned off, the touch capacitor Ct, the parasitic capacitor Cp, and the driving. The capacitor Cdrv and the common voltage capacitor Cvcom are isolated in a charged state. In this case, the input terminal of the level shift detector 212 may have a high impedance to stably isolate the charged charge.

The state in which the charges charged in the sensor pad 110 and the like are isolated is called a floating state. At this time, when the alternating voltage Vdrv applied to the driving capacitor Cdrv increases, for example, from 0 V to 5 V, the output voltage Vo of the sensor pad 110 is raised to a voltage level and then 5 V again. At 0V, the level of the output voltage Vo drops instantaneously. The rise and fall of the voltage level at this time will have different values depending on the connected capacitance. The rising or falling value of the voltage level according to the connected capacitance is also called "kick-back".

When there is no touch on the sensor pad 110, that is, when the capacitor connected to the sensor pad 110 has only the driving capacitor Cdrv and the parasitic capacitor Cp, the output voltage Vo by these capacitors Cdrv and Cp The voltage variation of ΔVo1 is expressed by Equation 1 below.

[Equation 1]

Where VdrvH and VdrvL are the high level voltage and the low level voltage of the alternating voltage Vdrv, respectively. ΔVo1 of Equation 1 corresponds to an electrical characteristic of the sensor pad 110 in which no touch occurs, and thus may be set to the “non-touch reference value” described above.

Next, a case in which the touch input tool is touched on the sensor pad 110 will be described. When a touch occurs, a touch capacitor Ct is formed between the sensor pad 110 and the touch input tool. Accordingly, the capacitor connected to the sensor pad 110 may include a touch capacitor (in addition to the driving capacitor Cdrv and the parasitic capacitor Cp). Ct) is added. As in the above-described method, the voltage variation ΔVo2 of the sensor pad 110 due to these three capacitors Cdrv, Cp, and Ct in the sensing period T4 through the charging period T3 is expressed by Equation 2 below. Lose.

[Equation 2]

Comparing [Equation 1] and [Equation 2], since the touch capacitance (Ct) is added to the denominator item of [Equation 2], the voltage fluctuation (ΔVo2) when there is a touch, the touch is It is small compared to the voltage fluctuation ΔVo1 in the absence, and the difference depends on the touch capacitance Ct. Thus, the difference (DELTA) Vo1-(DELTA) Vo2 of the voltage fluctuation (DELTA) Vo before and behind a touch is called "level shift."

Accordingly, the level shift is measured by measuring the variation ΔVo1 of the output voltage Vo at the sensor pad 110 when no touch occurs and the variation ΔVo2 of the output voltage Vo at the sensor pad 110 when the touch occurs. It can be detected whether or not it occurred, and it can be detected whether or not the touch occurs.

Naturally, the larger the level shift value, the more distinction is made between touch and non-touch. However, when the sensor pad 110 is in the floating state, the parasitic capacitance Cp is present in the denominator by referring to the formula of the variation of the output voltage Vo ΔVo1 and ΔVo2 according to the alternating voltage Vdrv. Can be.

One embodiment of the present invention is to adjust the value of the parasitic capacitance (Cp), to the magnitude of the variation of the output voltage (Vo) (ΔVo2) in the sensor pad 110 when a touch occurs due to the application of the alternating voltage (Vdrv) By reducing the margin of error, we want to improve touch sensitivity and enhance noise immunity.

First, the principle of generating the capacitance is as follows.

When the vicinity of conductors charged with different polarities is surrounded by a material having a dielectric constant (ε), the amount of charge (Q) collected in the conductor according to the magnitude of the potential between the conductors is called the capacitance (C). That is, the capacitance C may be expressed by Equation 3 below.

[Equation 3]

C = ε * A ／ d

Referring to Equation 3, the capacitance C is proportional to the area A of the conductor and inversely proportional to the distance d between the conductors.

In the touch detection device as shown in FIG. 2, a dielectric material such as glass or OCA exists between the sensor pads or the signal wires, and the sensor pads or signal wires are insulated from each other through the dielectric material. . Since the sensor pad and the signal wiring are conductors, the touch detection apparatus has a structure including a large number of conductors and a dielectric material present around them, that is, a capacitor structure forming a capacitance.

The undesired capacitance is formed by the width of each conductor (sensor pad or signal wiring), the distance between the conductors, and the dielectric constant (ε) of the dielectric material present between the conductors. do.

In particular, in a touch screen panel in which a plurality of sensor pads are arranged in a row and a column, the arrangement of the conductors is very dense and many are distributed, and thus the amount of parasitic capacitance Cp generated is very large. . Therefore, adjusting the parasitic capacitance Cp becomes an important factor affecting the performance related to touch detection in the touch screen panel.

Referring to FIG. 6, the parasitic capacitance controller 250 may be further included in the driving device 200 in the touch detection apparatus according to the exemplary embodiment of the present invention.

The parasitic capacitance control unit 250 according to an exemplary embodiment of the present invention has a signal line adjacent to a signal line of a specific sensor pad that outputs a voltage of an output terminal of a specific sensor pad to be detected as a current touch among the plurality of sensor pads 110. Supply to other sensor pads. For this reason, the parasitic capacitance controller 250 may attenuate the parasitic capacitance generated between a specific sensor pad which is a touch detection object among a plurality of sensor pads and another adjacent sensor pad.

FIG. 7 is a diagram illustrating n sensor pads belonging to one column and illustrating the principle of parasitic capacitance attenuation. Referring to FIG. 7, the parasitic capacitance control unit 250 may change the output terminal voltages of the sensor pads 110-i that are currently detected as touch targets among the plurality of sensor pads belonging to the same column to different sensor pads 110-1 and 110-. 2, ..., 110-n). In addition, the parasitic capacitance controller 250 may include a buffer 251 for preventing short between the sensor pads 110-1, 110-2,..., 110-n that are arranged in isolation. . That is, the output terminal voltage of the sensor pad 110-i, which is the current touch detection object, is input to the buffer 251, and the output terminal of the buffer 251 is connected to the other sensor pads 110-1, 110-2,. -n).

When the parasitic capacitance is attenuated by the parasitic capacitance control unit 250 will be described.

In a capacitor structure composed of two conductors and a dielectric material present therebetween, the charge amount Q charged in the structure may be expressed by a formula such as Q = CV. Where C is the capacitance value of the structure, and V is the potential difference between the two conductors.

In the above formula, when the voltage V is converged to be close to zero, the amount of charge Q drawn by the potential difference between conductors can also be converged to be close to zero. Since the capacitance C is proportional to the charge capacity of the charge, if the amount of charge Q to be charged is close to zero, it means that the capacitance C formed by the relationship between conductors also converges close to zero.

Referring back to FIG. 7, an embodiment of the present invention uses the above principle, and when detecting whether a specific sensor pad 110-i is touched, the sensor pad 110-i may be located around the sensor pad 110-i. By controlling the potentials of the sensor pads 110-1, 110-2,..., 110-n to be close to the same level, the parasitic capacitance Cp affecting the detection of touch is compensated to be close to '0'. will be.

For example, as illustrated in FIG. 7, the output terminal voltage of the sensor pad 110-i, which is the current touch detection target among the sensor pads belonging to the same column, may be changed through another buffer pad 251 through the buffer 251 of the attenuation unit 250. When applied to 110-1, 110-2, ..., 110-n, respectively, the potential difference between the sensor pad 110-i and the other sensor pads 110-1, 110-2, ..., 110-n is minimized. Accordingly, the parasitic capacitance generated by the relationship between the sensor pads can be effectively attenuated.

Meanwhile, in FIG. 7, the output terminal of the sensor pad 110-i is connected to other sensor pads 110-1, 110-2,..., 110-n belonging to the same row as the sensor pad 110-i which is the touch detection target. Although described as applying a voltage, the present invention is not limited thereto, and the sensor is applied to other sensor pads belonging to the same row as the plurality of sensor pads 110-i according to the connection form of the signal wires connecting the respective sensor pads and the driving device. The output terminal voltage of the pad 110-i may be applied.

FIG. 8 is a diagram schematically illustrating a touch detection apparatus including a plurality of sensor pad columns including a plurality of sensor pads, and illustrating an arrangement of each sensor pad and signal wires connected thereto.

The size of the parasitic capacitance Cp generated between the sensor pad 110 and the signal wire 120 connected to the sensor pad 110 increases in a section in which the density of the mutual electric flux is high. As described above, since the capacitance increases as the distance between conductors increases, the parasitic capacitance Cp is largely generated due to the relationship between the signal wires 120 between the adjacent sensor pads 110.

Referring to FIG. 8, the signal wires 120 of the sensor pads 110 belonging to the same column are arranged in close proximity. For example, referring to the relationship between the first sensor pad 110-1 and the second sensor pad 110-2 arranged in the same column, the first signal wire 120 connected to the first sensor pad 110-1 is described. 2 and the second signal wire 120-2 connected to the second sensor pad 110-2 are arranged side by side at a very close distance, and the total length of the second signal pads 110-2 adjacent to each other is adjacent to the second sensor pad 110-2. 2) and the driving device 200 (see FIG. 6). On the other hand, in comparison with each other, in the relationship between the sensor pads belonging to different columns, the parasitic capacitance Cp is formed relatively small because the distance between the signal wires 120 connected to each sensor pad 110 is far apart. .

That is, a sensor belonging to the same column having a distance between the signal wires 120 of the sensor pads closer to the parasitic capacitance Cp generated between the sensor pads belonging to different columns having a farther distance between the signal wires 120 of each sensor pad. The parasitic capacitance Cp occurring between the pads becomes relatively large.

Therefore, in the exemplary embodiment of the present invention, in order to minimize the parasitic capacitance Cp formed between the adjacent sensor pads 110, the output terminal voltage of the sensor pad 110 to be detected whether the touch is detected and the signal wires of the corresponding sensor pads. It is supplied to another sensor pad 110 having an adjacent signal line.

On the other hand, the size of the parasitic capacitance Cp between the sensor pads 110 becomes larger as the sensor pad 110 is disposed at a far distance from the driving device 200 (see FIG. 6). As the distance from the driving device 200 increases, the length of each signal wire 120 connected to the corresponding sensor pad 110 and the neighboring sensor pad 110, that is, the signal wire connected to each sensor pad 110 is increased. This is because the length of the 120 arranged side by side becomes longer.

At the time of detecting whether the touch is detected, the touch area (Ct) generated between the touch means (for example, a finger) and the sensor pad 110 is grasped to detect the touch area. The magnitude of the touch capacitance Ct should be clearly calculated. Therefore, it is desirable to be relatively unaffected by the size of the parasitic capacitance Cp.

As described above, since a relatively large parasitic capacitance Cp is formed in the relationship between the driving device 200 and the sensor pads 110 disposed at a long distance, in order to further reduce this effect, As shown in the figure, the sensor pad 110 disposed farther from the driving device 200 has a larger area.

Referring to FIG. 9, the output terminal voltage Vo of the sensor pad 110 selected by the touch detector 210 as the current touch detection object passes through the buffer 251 of the parasitic capacitance controller 250 to signal wiring of a specific sensor pad. It can be seen that it is input to other sensor pads 110 'having a signal wire adjacent to the. In detail, an input terminal of the buffer 251 may be connected to an output terminal of the sensor pad 110 that is a current touch detection target, and an output terminal of the buffer 251 may be connected to another sensor pad 110 ′, respectively. The buffer 251 may be implemented as a buffer amplifier that functions to prevent short circuits, adjust signals, and prevent interference between the sensor pad 110 and the other sensor pad 110 ′ currently being detected. Can be. At this time, since the output terminal voltage Vo of the sensor pad 110 to be detected is applied to another sensor pad 110 'as it is, the potential between the sensor pads must be made at the same level. Therefore, the gain of the buffer amplifier should be 1, It may be changed as necessary. That is, the gain of the buffer 251 included in the parasitic capacitance controller 250 may be changed to bring the potential difference between the sensor pads 110 close to '0'.

Through the parasitic capacitance control unit 250, the parasitic capacitance Cp, which is the largest contributing part of the parasitic capacitance Cp, that is formed according to the relationship between adjacent sensor pads, may be reduced to a minimum.

Since the description of the other components of the touch detector 210 and the touch detection operation have been described in detail with reference to FIG. 4, the description thereof will be omitted.

Conventionally, all of the sensor pads 110 'including the sensor pads 110 to be touch detected have been collectively set to any one of floating, ground, or precharge. .

However, according to an exemplary embodiment of the present invention, the output terminal voltage Vo of the specific sensor pad 110 to be detected by the touch is connected to the specific sensor pad 110 and the specific sensor pad through the parasitic capacitance controller 250. Each is applied to another sensor pad 110 'having a signal line and an adjacent signal line. Therefore, the sensor pad 110 and the other sensor pads 110 ′ which are the touch detection targets may both be in a floating state. In addition, the sensor pads 110 and the sensor pads that do not belong to the other sensor pads 110 ′ may be set to any one of floating, ground, or precharge as in the conventional method. Can be.

On the other hand, the parasitic capacitance control unit may adjust the parasitic capacitance existing between the sensor pads 110 in a different manner.

Referring to FIG. 10, the driving device 200 of the touch detection apparatus according to another exemplary embodiment may further include a parasitic capacitance controller 260.

The parasitic capacitance control unit 260 may determine the output terminal voltage of the specific sensor pad detected in the first frame and the specific sensor pad in the second frame with respect to the specific sensor pad that is currently detected as a touch target among the plurality of sensor pads 110. When a touch is detected, the signal is supplied to another sensor pad connected to the signal wire adjacent to the signal wire of the specific sensor pad. For this reason, the parasitic capacitance controller 260 may adjust the parasitic capacitance generated between the specific sensor pad which is a touch detection object among the plurality of sensor pads and another adjacent sensor pad. Here, the frame refers to one period of detecting voltage values for the plurality of sensor pads 110 to detect the touch position.

To this end, the parasitic capacitance controller 260 may include a buffer 261 (see FIG. 12) and a multiplexer 262 (see FIG. 12), which will be described later with reference to FIGS. 12 to 13.

FIG. 11 is a diagram illustrating n sensor pads belonging to one column and illustrating the principle of parasitic capacitance adjustment.

The parasitic capacitance controller 260 may include a buffer 261 for preventing short between the sensor pads 110-1, 110-2,..., 110-n that are arranged in isolation.

In a capacitor structure composed of two conductors and a dielectric material present therebetween, the charge amount Q charged in the structure is equal to Q = CV as described above. In this equation, increasing the capacitance (C) reduces the voltage (V), that is, the potential difference between the two conductors in the absence of the inflow or outflow of the charge (Q).

Referring back to FIG. 11, an embodiment of the present invention uses the above principle, and when detecting a touch on a specific sensor pad 110-i that is a touch detection target, the specific sensor pad 110-in the previous frame. i) By inputting the output voltage to the sensor pads (110-1, 110-2, ..., 110-n) in the periphery through the buffer 261 in the current frame, the output terminal voltage of the sensor pad (110-i) and The capacitance is generated between the other sensor pads 110-1, 110-2,..., 110-n, thereby reducing the change range of the value of the output terminal voltage of the sensor pad 110-i.

Specifically, the case where the output terminal voltage of the specific sensor pad 110-i detected in the first frame is 2V and the output terminal voltage of the specific sensor pad 110-i detected in the second frame is 0 V will be described below. Same as

When the output terminal voltage 2V of the specific sensor pad 110-i detected in the first frame is touched on the specific sensor pad 110-i in the second frame, the other sensor pads 110-1, 110-2,. , 110-n), the output terminal voltage of the specific sensor pad 110-i is 0V in the second frame, or 2V is applied to the other sensor pads 110-1, 110-2, ..., 110-n. do. As a result, a potential difference occurs between the specific sensor pad 110-i and the other sensor pads 110-1, 110-2,..., 110-n, and the capacitance C is generated. At this time, since the charge amount Q is not newly generated or lost, the voltage V decreases when the capacitance C is generated and increased in a constant state. At this time, the voltage V is the output terminal voltage of the specific sensor pad 110-i detected when the touch is detected on the specific sensor pad 110-i in the second frame and the specific sensor pad 110 detected in the first frame. -i) means the potential difference between the output terminal voltage. Therefore, as a result, the output terminal voltage of the specific sensor pad 110-i detected in the first frame and the touch of the specific sensor pad 110-i detected when the touch is detected on the specific sensor pad 110-i in the second frame. The potential difference between the output terminal voltages is reduced.

That is, when the touch detection for the current specific sensor pad is applied, when the output terminal voltage of the previously detected specific sensor pad is applied to another sensor pad, the output terminal voltage of the currently detected specific sensor pad is applied to other sensor pads, respectively. The touch sensitivity may be improved by reducing an error range with respect to a value between output terminal voltages of a specific sensor pad detected in a frame.

12 is a diagram illustrating an example of a parasitic capacitance controller of a touch detection apparatus according to another embodiment of the present invention.

Referring to FIG. 12, the parasitic capacitance control unit 260 measures the output terminal voltage of the specific sensor pad 110-i that is a touch detection object among the plurality of sensor pads detected in the first frame, and the sensor pad in the second frame. Upon touch detection for 110-i, it is supplied to other sensor pads 110-1, 110-2,..., 110-n.

In addition, the parasitic capacitance controller 260 may include a buffer 261 and a multiplexer 262. At this time, the buffer 261 is for preventing short between each of the sensor pads 110-1, 110-2,..., 110-n that are arranged in isolation, and the multiplexer 262 is used for another sensor pad ( To select the output terminal voltage of the specific sensor pad 110-i supplied to 110-1, 110-2,. Specifically, the output terminal voltage of the specific sensor pad 110-i to be detected as touch is input to the buffer 261, the output terminal of the buffer 261 is connected to the input terminal of the multiplexer 262, and the multiplexer 262. The output terminal of may be connected to the other sensor pads (110-1, 110-2, ..., 110-n). At this time, the multiplexer 262 selects one of an output terminal voltage of the specific sensor pad 110-i detected in the first frame and an output terminal voltage of the specific sensor pad 110-i detected in the second frame. It can be selectively applied to the other sensor pad (110-1, 110-2, ..., 110-n), respectively.

When the multiplexer 262 detects a touch on the specific sensor pad 110-i in the second frame, the multiplexer 262 may change the output terminal voltage of the specific sensor pad 110-i detected in the first frame to be different from the sensor pads 110-1 and 110. -2, ..., 110-n). However, the multiplexer 262 may change the output terminal voltage of the specific sensor pad 110-i detected in the second frame when the touch of the specific sensor pad 110-i is detected in the second frame only under a predetermined condition. The sensor pads 110-1, 110-2, ..., 110-n can be supplied. For example, the multiplexer 262 detects touch on a specific sensor pad 110-i in the second frame when the output terminal voltage of the specific sensor pad 110-i is higher than a reference value for touch detection in the second frame. The output terminal voltage of the specific sensor pad 110-i detected in the second frame may be supplied to other sensor pads 110-1, 110-2,..., 110-n. In this case, the reference value may be set in advance to a value of an output terminal voltage of the sensor pad 110-i that is detectable when a touch occurs.

That is, when the difference between the output terminal voltage of the specific sensor pad 110-i in the first frame and the output terminal voltage of the specific sensor pad 110-i in the second frame is greater than or equal to the threshold value, the multiplexer 262 may determine the specific sensor in the second frame. When the touch of the pad 110-i is detected, the output terminal voltage of the specific sensor pad 110-i in the second frame instead of the first frame is set as the peripheral sensor pads 110-1, 110-2,..., 110-n. ) Can be entered. In this case, since the state change occurred from touch to non-touch or non-touch to touch between the first frame and the second frame, it is necessary to reduce the output terminal voltage difference of the sensor pad 110 detected in both frames. Because there is no.

In addition, when the first frame is the first frame when detecting the touch of the specific sensor pad 110-i in the first frame, the multiplexer 262 outputs the voltage of the output terminal of the specific sensor pad 110-i detected in the first frame. Can be supplied to other sensor pads 110-1, 110-2, ..., 110-n. This is because when there is no output terminal voltage of the specific sensor pad 110-i for the previous frame when the first frame is the first frame, the multiplexer 262 detects the specific sensor detected in the first frame through the buffer 261. The output terminal voltage of the pad 110-i is supplied to the other sensor pads 110-1, 110-2,..., 110-n. For this reason, in the first frame, parasitic capacitance generated by the relationship between the sensor pads can be attenuated, thereby preventing errors in the detection of touch. Specifically, since the voltage V converges to 0 in the formula of Q = CV, the capacitance C, that is, the sensor pads 110-1, 110-2, ..., 110 different from the specific sensor pad 110-i. parasitic capacitance between -n) is reduced. Therefore, the voltage variation ΔVo2 calculated through Equation 2 is increased, so that the accuracy of initial touch detection may be improved.

Meanwhile, the output terminal voltage of the specific sensor pad 110-i is described in such a manner that one of the output terminal voltages of the specific sensor pad 110-i detected in the first frame and the second frame is selected through the multiplexer 262. However, the present invention is not limited thereto, and the output terminal voltage of the specific sensor pad 110-i may be stored in the memory 230 and then input to the multiplexer 262. That is, the output terminal voltage of the specific sensor pad 110-i may be stored in the memory 230 (see FIG. 3), and the output terminal voltage of the specific sensor pad 110-i stored in the memory 230 may be the multiplexer 262. Can be entered. For example, the output terminal voltage of the specific sensor pad 110-i detected in the first frame is pre-stored in the memory 230 by analog-to-digital conversion, and for the specific sensor pad 110-i in the second frame. When the touch is detected, as the output terminal voltage of the specific sensor pad 110-i detected in the first frame is digital-analog converted and input to the multiplexer 262, other sensor pads 110-1, 110-2,. 110-n), respectively. In this case, the output terminal voltage of the specific sensor pad 110-i detected in the second frame may be analog-digital converted and stored in the memory 230.

Referring to FIG. 13, the output terminal voltage Vo of the sensor pad 110 detected in the first frame is detected in the second frame with respect to the sensor pad 110 selected as the current touch detection target by the touch detector 210. The other sensor pads 110 ′ connected to the signal wires adjacent to the signal wires of the sensor pad 110 through the buffer 261 and the multiplexer 262 of the parasitic capacitance controller 260 when the touch on the pad 110 is detected. Is entered. Specifically, the input terminal of the buffer 261 is connected to the output terminal of the sensor pad 110 to be the current touch detection target, the output terminal of the buffer 261 is connected to the input terminal of the multiplexer 262, the output terminal of the multiplexer 262 May be connected to different sensor pads 110 ', respectively.

The buffer 261 may be implemented as a buffer amplifier that functions to prevent shorts, adjust signals, and prevent interference between the sensor pad 110 and the other sensor pad 110 'that are currently detected as touches. Can be. In this case, the output terminal voltage Vo of the sensor pad 110, which is the detection target detected in the first frame, must be applied to the other sensor pad 110 ′ when the touch of the sensor pad 110 is detected in the second frame. However, the gain of the buffer amplifier should be 1, but may be changed as necessary. That is, the gain of the buffer 261 included in the parasitic capacitance controller 260 may be changed to reduce the potential difference between the sensor pad 110 in the first frame and the second frame.

The parasitic capacitance control unit 260 adjusts the parasitic capacitance Cp that contributes the most, that is, the parasitic capacitance Cp formed according to the relationship between adjacent sensor pads, thereby detecting the sensor pad 110 during touch detection. It is possible to improve the sensitivity to touch detection by reducing the error range of the output terminal voltage value.

According to an embodiment of the present invention, the parasitic capacitance generated by the parasitic capacitance controller 260 between adjacent sensor pads may be suppressed or generated. As a result, the parasitic capacitance can be adjusted, thereby reducing the error range of the output terminal voltage value of the sensor pad, thereby improving the sensitivity of detecting the touch occurrence.

Meanwhile, referring to FIG. 14, in the touch detection apparatus according to the embodiment of the present invention, a dummy line 300 may be further formed between a column composed of a plurality of sensor pads and a neighboring column.

This is to attenuate the parasitic capacitance Cp due to the relationship between the specific sensor pad 110 and the sensor pad 110 ″ belonging to the neighboring heat.

Specifically, the signal wires 120 connected to the sensor pads 110 belonging to a specific column also have a parasitic capacitance Cp even in a relationship with the signal wires 120 ″ connected to the sensor pads 110 ″ belonging to another column. Can be generated. In particular, in the light of the arrangement of the signal wires 120, the sensor wires 110 that are farther from the driving device 200 (see FIGS. 6 and 10) are connected to the sensor wires 110 in the neighboring rows. Because it is in close proximity to the signal line 120 '' connected to ''), a more severe parasitic capacitance Cp is generated in relation to the sensor pad 110 '' belonging to the neighboring column.

In order to attenuate the parasitic capacitance Cp generated in the relationship between neighboring columns, a dummy line 300 may be formed between the columns.

The dummy line 300 may extend in a direction away from the driving device 200 (see FIGS. 6 and 10), that is, in a column direction between rows.

Although no signal may be applied to the dummy line 300 disposed between the column and the column, the signal may be applied from the driving device 200 (see FIGS. 6 and 10).

FIG. 15 is a diagram illustrating a configuration of a touch detection apparatus according to an embodiment of the present invention, and illustrates a principle in which a driving signal is applied to a dummy line 300 disposed between columns.

Referring to FIG. 15, when the plurality of sensor pads 110 are arranged in a matrix form of N × M in the touch panel 100, N multiplexers MUX are provided in the touch detection unit 210 of the driving device 200. Include.

That is, one multiplexer MUX is provided for one column, and the multiplexer MUX selects one of the M sensor pads 110 belonging to one column. To this end, M multiple sensor pad selection pins SP are provided in the multiplexer MUX, and M sensor pad selection pins SP are connected to M sensor pads 110 belonging to one column through signal lines. . The sensor pad 110 selected by the multiplexer MUX is supplied with a driving signal to detect whether a touch is made. In this case, the corresponding driving signal may be supplied to the dummy line 300 disposed on the left and right of the column to which the sensor pad 110 to be touch detected belongs. To this end, the multiplexer MUX may further include a dummy line driving pin DP. The dummy line driving pin DP allows the corresponding driving signal to be supplied to the dummy line 300 when the driving signal for detecting the touch of the sensor pad 110 is applied. That is, the dummy line 300 may be connected to the dummy line driving pin DP provided in the multiplexer MUX of the touch detector 210.

When a touch detection operation is performed on a specific sensor pad 110, the sensor pads belonging to a column adjacent to the sensor pad 110 may have different potentials, and thus, parasitics may be caused by the relationship between the sensor pads belonging to the neighboring rows. Capacitance Cp may occur. However, as shown in FIG. 15, if a driving signal is also applied to the dummy line 300 during the touch detection operation on the specific sensor pad 110, the dummy line 300 which is the closest conductor to the corresponding sensor pad 110. ) Has substantially the same potential, so that parasitic capacitance Cp due to the relationship between heat and heat can also be prevented.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is represented by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention.

Claims

In the touch detection device of the touch panel comprising a plurality of sensor pads and signal wires connected to each of the plurality of sensor pads,

Parasitic capacitance control unit for controlling the parasitic capacitance generated between the specific sensor pad to be detected whether the touch of the plurality of sensor pads and the other adjacent sensor pad,

And the parasitic capacitance controller is configured to apply an output terminal voltage of the specific sensor pad to another sensor pad connected to a signal wire adjacent to a signal wire of the specific sensor pad.
The method of claim 1,

The parasitic capacitance control unit,

And an output terminal voltage of the specific sensor pad is applied to the other sensor pad at the time of detecting the specific sensor pad.
The method of claim 2,

The parasitic capacitance control unit includes a buffer,

And an input terminal of the buffer is connected to an output terminal of the specific sensor pad, and an output terminal of the buffer is connected to the other sensor pad, respectively.
The method of claim 1,

The parasitic capacitance control unit,

And one of the output terminal voltages of the specific sensor pad detected in the first frame and the second frame is selectively applied to the other sensor pad in the second frame.
The method of claim 4, wherein

The parasitic capacitance controller includes a buffer and a multiplexer,

And an input terminal of the buffer is connected to an output terminal of the specific sensor pad, an output terminal of the buffer is connected to an input terminal of the multiplexer, and an output terminal of the multiplexer is respectively connected to the other sensor pad.
The method of claim 4, wherein

The parasitic capacitance controller selects one of an output terminal voltage of the specific sensor pad detected in the first frame and the second frame and applies the applied voltage to the other sensor pad, respectively.
The method of claim 4, wherein

The parasitic capacitance controller is configured to apply an output terminal voltage of the specific sensor pad to the other sensor pad in the first frame when the first frame is the first frame.
The method of claim 4, wherein

When the output terminal voltage of the specific sensor pad detected in the second frame is higher than a reference value for touch detection, the parasitic capacitance controller applies the output terminal voltage of the specific sensor pad to the other sensor pad in the second frame. Touch detection device.
The method of claim 1,

The plurality of sensor pads are disposed in a row and a column direction, and a dummy line is disposed between the columns and the columns to suppress parasitic capacitance generation due to a relationship between sensor pads belonging to adjacent columns.
The method of claim 1,

And the plurality of sensor pads have a larger area away from the driving device for driving the sensor pads.
In the touch detection method of a touch panel comprising a plurality of sensor pads and signal wires connected to each of the plurality of sensor pads,

Controlling parasitic capacitance by applying an output terminal voltage of a specific sensor pad, which is a touch detection object, of the plurality of sensor pads to another sensor pad connected to a signal wire adjacent to a signal wire of the specific sensor pad; And

Detecting whether or not the touch based on the difference in the output terminal voltage change of the specific sensor pad,

And the attenuation step causes the output terminal voltage of the specific sensor pad to be applied to another sensor pad having a signal wiring adjacent to the signal wiring of the specific sensor pad at the detection timing of the specific sensor pad.
The method of claim 11,

The parasitic capacitance control step,

And causing the output terminal voltage of the specific sensor pad to be applied to the other sensor pad at the time of detecting the specific sensor pad.
The method of claim 11,

The parasitic capacitance control step,

And causing one of the output terminal voltages of the specific sensor pad detected in the first frame and the second frame to be selectively applied to the other sensor pad in the second frame.
The method of claim 13,

The parasitic capacitance control step,

And if the first frame is the first frame, causing the output terminal voltage of the specific sensor pad to be applied to the other sensor pad in the first frame.
The method of claim 13,

The parasitic capacitance control step,

If the output terminal voltage of the specific sensor pad detected in the second frame is higher than a reference value for touch detection, causing the output terminal voltage of the specific sensor pad to be applied to the other sensor pad in the second frame. Touch detection method.