KR20130136357A - Device for detecting touch - Google Patents

Abstract

According to one embodiment of the present invention, a touch detecting device having an enhanced touch detecting property and capable of extracting an exact touch coordinate is provided. The touch detecting device according to the embodiment of the present invention comprises a touch panel, a driving device and a circuit substrate. The touch panel comprises a substrate, multiple sensor pads of transparent material arranged on the substrate, and multiple signal wires connected respectively to the sensor pad. The driving device drives the touch panel. The sensor pads are repetitively arranged at two unit columns forming one basic column and the basic column is repetitively arranged in a row direction.

Description

Touch Detection Device {DEVICE FOR DETECTING TOUCH}

The present invention relates to a touch detection device, and more particularly, to a touch detection device in which touch sensitivity is improved and accurate touch coordinates can be extracted.

The touch screen panel is an input device for inputting a user's command by touching with a human hand or other contact means based on the content displayed by the image display device.

To this end, the touch screen panel is provided on the front face of the image display device to convert a contact position directly contacted by a human hand or other contact means into an electrical signal. Accordingly, the instruction selected at the contact position is received 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 formed by a conductive sensor pattern or other sensor pattern or ground electrode when a human hand or an object is touched.

1 is an exploded top view of an example of a conventional capacitive touch screen panel.

The conventional touch screen panel 1 includes a transparent substrate 2, a first sensor pattern 3, a first insulating film 4, a second sensor pattern 5, and a second insulating film sequentially formed on the transparent substrate 2. 6) and a position detection line 7.

The first sensor pattern 3 is formed to be connected in a transverse direction on one surface of the transparent substrate 2. For example, the first sensor pattern 3 may be formed in a regular pattern in which a plurality of diamond shapes are lined up on the transparent substrate 2.

The first sensor pattern 3 may be formed of a plurality of Y patterns formed so that the first sensor patterns 3 positioned in one row having the same Y coordinate are connected to each other, and the position detection line 7 is provided in units of rows. Connected with

The second sensor pattern 5 is formed to be connected in the column direction on the first insulating film 4, and is alternately disposed with the first sensor pattern 3 so as not to overlap the first sensor pattern 3. For example, the second sensor pattern 5 may be formed in the same diamond pattern as the first sensor pattern 3, and the second sensor patterns 5 positioned in one column having the same X coordinate are connected to each other. In addition, the second sensor pattern 5 is connected to the position detection line 7 in units of columns.

Meanwhile, the first and second sensor patterns 3 and 5 are made of a transparent conductive material such as indium tin oxide (ITO), and the first insulating film 4 is made of a transparent insulating material.

The sensor patterns 3 and 5 of the unit are respectively electrically connected to the position detection line 7 to supply a contact position signal to a driving circuit (not shown) or the like.

When a hand or an object comes into contact with the touch screen panel 1 illustrated in FIG. 1, the capacitance of the capacitance according to the contact position is moved to the driving circuit side via the first and second sensor patterns 3 and 5 and the position detection line 7. Change is communicated. And the contact position is grasped | ascertained as the change of capacitance is converted into an electrical signal by X and Y input processing circuits (not shown) etc.

However, the conventional touch screen panel 1 must have an ITO pattern in each layer for X and Y, and an insulating layer must be provided between the X layer and the Y layer, thereby increasing thickness. In addition, since capacitive changes generated by touch are accumulated several times, touch detection is required to detect capacitive changes at a high frequency. This requires complex computational and statistical processing.

In addition, since the difference between the electrical signals before and after the touch is extremely minute, it is affected by the wiring resistance, which requires metal wiring to maintain low resistance. An additional mask process is needed to form this metal wiring.

In addition, since touch detection of the conventional touch screen panel 1 is highly dependent on the resistance value and sensitive to noise, there are many difficulties in increasing the touch detection sensitivity. In particular, the touch capacitance is not grounded when the touch is touched, but the human body responds to the antenna, and noise signals of environmental frequency components are introduced into the touch panel as input. In fact, in the environment using 50Hz or 60Hz home power, the electric signal from the fingertips is interrupted by the electric field generated from the home power, and the input signal of the corresponding frequency enters the touch sensing node. When the human body radiation noise signal is introduced into the touch panel, the touch detection value by the touch is greatly changed, and it is impossible to distinguish whether or not the touch is made.

Furthermore, the conventional touch screen panel 1 detects a touch by using a minute change of capacitance accumulated several times through complicated calculations, and thus it is not possible to calculate an accurate touch area. Thus, it was practically impossible for a user to use the touch area as one means of user input.

In order to solve the above problems, the technical problem to be achieved by the present invention is to provide a touch detection device that can improve the touch sensitivity, extract the correct touch coordinates.

In order to achieve the above technical problem, an embodiment of the present invention includes a touch panel having a substrate, a plurality of sensor pads of a transparent material disposed isolated on the substrate, and a plurality of signal wires respectively connected to the sensor pads; And a driving device for driving the touch panel, wherein the sensor pad is repeatedly disposed in two unit columns constituting one basic column, and the basic column is repeatedly disposed in a row direction. to provide.

Here, the sensor pads are formed extending in the column direction, symmetrically formed with respect to each other with respect to the center, and are formed to extend in the column direction with a first sensor pad that is repeatedly arranged in the two unit rows in the one basic column. And a second sensor pad disposed in at least one unit column of the basic column in which the first sensor pad is disposed adjacent to the first sensor pad.

The first sensor pad may have a first unit sensor pad formed to have an area wider from the center to one end, and a second unit sensor pad formed to have a wider area from the center to the other end.

The second sensor pad may be formed in a shape corresponding to the first unit sensor pad or the second unit sensor pad, and the first unit sensor pad or the second unit sensor pad may be disposed in one unit row. One pair may be arranged in the other unit column.

The first sensor pad may have a pentagonal shape, and the second sensor pad may have a right triangle shape.

In addition, an area of the first sensor pad and the second sensor pad provided closest to the driving device in each of the basic rows may be smaller than that of the remaining first sensor pad and the second sensor pad.

Meanwhile, in order to achieve the above technical problem, an embodiment of the present invention provides a touch having a substrate, a plurality of sensor pads of a transparent material disposed on the substrate, and a plurality of signal wires connected to the sensor pads, respectively. A touch detection device including a panel and a driving device for driving the touch panel, and including a portion of a first sensor pad and a portion of a second sensor pad adjacent to each other among the sensor pads to form a virtual sensing area. to provide.

Here, the number of virtual sensing regions may be larger than the number of sensor pads.

According to the present invention, the number of sensor pads can be reduced, and thus, the size of the driving device can be reduced, so that mounting is advantageous and the number of signal wires can be reduced, so that the influence of parasitic capacitance generated between the signal wires By reducing the touch sensitivity can be improved.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is an exploded plan view of a conventional touch screen panel.
2 is an exploded plan view of a touch detection apparatus according to an embodiment of the present invention.
3 is a block diagram illustrating a configuration 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 exemplary embodiment of the present invention.
5 is an exemplary waveform diagram of a touch detection unit according to an embodiment of the present invention.
6 is a schematic diagram illustrating a state in which a charging voltage is charged in a capacitor in a charging section of the waveform diagram shown in FIG. 5.
7 is a block diagram of a level shift detection unit according to an embodiment of the present invention.
FIG. 8 is an exemplary circuit diagram of the buffer unit and the amplifier unit shown in FIG. 7.
9 is a schematic diagram showing input and output signals by the circuit shown in FIG.
FIG. 10 is a schematic diagram illustrating a filtering process of an output signal of the circuit shown in FIG. 8.
11 is a block diagram of a touch information processor according to an embodiment of the present invention.
12 is a schematic diagram illustrating a structure of a memory in which information about a sensor pad is stored according to an exemplary embodiment of the present invention.
13 is a flowchart illustrating a touch detection method according to an embodiment of the present invention.
14 is an exploded view illustrating a touch detection device according to another embodiment of the present invention.
15 is a plan view illustrating a touch detection device according to another embodiment of the present invention.
16 and 17 are diagrams illustrating touch sensitivities of a touch detection device according to another embodiment of the present invention.
18 is an exemplary view comparing sensor pads of a touch detection apparatus according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" . Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

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

2 is an exploded plan view of a touch detection apparatus according to an embodiment of the present invention, and FIG. 3 is a block diagram illustrating a configuration of a touch detection apparatus according to an embodiment of the present invention.

2 and 3, the touch detection apparatus according to the present embodiment includes a touch panel 100, a driving device 200, and a circuit board 20 connecting the two.

The touch panel 100 includes a plurality of sensor pads 110 formed on a substrate 15 such as glass or plastic film of transparent material and a plurality of signal wires 120 connected thereto.

The plurality of sensor pads 110 may be, for example, rectangular or rhombic, but is not limited thereto. The sensor pad 110 may be implemented in a polygonal shape of a uniform shape. The sensor pads 110 may be arranged in a matrix form of substantially adjacent polygons.

Each signal wire 120 has one end connected to the sensor pad 110 and the other end extending to the bottom edge of the substrate 15. The line width of the signal wire 120 may be designed to be quite narrow, on the order of several tens to several tens of micrometers.

The sensor pad 110 and the signal wire 120 may be formed of indium-tin-oxide (ITO), antimony tin oxide (ATO), indium-zinc-oxide (IZO), carbon nanotube (CNT), and graphene. It can be made of a transparent conductive material.

The sensor pad 110 and the signal wiring 120 can be formed simultaneously by, for example, laminating an ITO film on the substrate 15 by a sputtering method or the like and then patterning the same using an etching method such as photolithography.

The sensor pad 110 and the signal wire 120 may be covered with a transparent insulating film 10.

The driving device 200 for driving the touch panel 100 may be formed on a circuit board 20 such as a printed circuit board or a flexible circuit film, but is not limited thereto and may be directly mounted on a part of the substrate 15. have. 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 is connected to the signal wire 120, receives a signal from the controller 240, drives circuits for touch detection, and outputs a voltage corresponding to the determination result of the touch detection. The touch detector 210 may include a plurality of switches and capacitors connected to the sensor pad 110.

In addition, the touch detector 210 converts, amplifies, or digitizes the difference in the voltage change of the sensor pad 110 and stores the difference in the memory 230, and may include an amplifier and an analog-digital converter.

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

The memory 240 stores the digital voltage based on the difference in the voltage change detected by the touch detector 210 and predetermined data used for touch detection, area calculation, and touch calculation or data received in real time.

As described above, 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.

A detailed embodiment and operation of the touch panel and the touch detector will be described in detail with reference to FIGS. 4 to 6.

4 is a circuit diagram illustrating a touch detector according to an embodiment of the present invention, FIG. 5 is an exemplary waveform diagram of a touch detector according to an embodiment of the present invention, and FIG. 6 is a waveform diagram of FIG. 5. A schematic diagram showing a state in which a charging voltage is charged in a capacitor in a charging section.

Referring to FIG. 4, the touch detector 210 includes a plurality of selectable resistors R1 to Rn, a plurality of transistors 211 for switching operation, a plurality of parasitic capacitors Cp, and a plurality of driving capacitors Cdrv. And a plurality of common capacitors Cvcom and a plurality of level shift detection units 212, and are connected to the sensor pads 110 through the signal wires 120. The transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, the common capacitor Cvcom, and the level shift detector 212 may be grouped one by one for the sensor pad 110 and the signal wiring 120. The sensor pad 110, the signal wiring 120, the transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, and the common capacitor Cvcom are collectively referred to as a “touch cell”. The touch cell is a concept including a case where each component is electrically connected by a multiplexer. For convenience, the same reference numerals are used for capacitors and their capacitances.

The transistor 211 is a field effect transistor, for example, a control signal Vg may be applied to a gate, a charging signal Vb may be applied to a source (or drain), and a drain (or source) may be a signal wire ( 120). The control signal Vg and the charging signal Vb may be applied by the control of the controller 240. Instead of the transistor 211, other devices capable of switching may be used.

One of the plurality of resistors R1 to Rn is selected and connected between the charging signal Vb and 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 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 the display device (not shown). A common voltage Vcom such as a square wave is applied to the common electrode by the display device. Meanwhile, the common capacitance Cvcom may also be included in the parasitic capacitance Cp as a parasitic capacitance, and unless otherwise stated, the common capacitance Cvcom will be described as being included in the parasitic capacitance 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 drive 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.

In the future, the cell may be disposed at a position where the user cannot touch or may have a cell having electrical characteristics that are not always touched. The "reference cell" may exist physically, but may be a virtual cell having only data values.

Referring to FIG. 5, the controller 240 may apply the charging signal Vb and the control signal Vg to the source and gate of the transistor 211, respectively.

First, the case in which the touch input tool is not touched to the sensor pad 110 will be described. After the charge signal Vb rises to, for example, 10V, the control signal Vg applied to the gate of the transistor 211 rises from the low voltage VL to the high voltage VH, and the charge period T1 starts. (211) is turned on. Accordingly, the sensor pad 110 starts to be charged by the charging signal Vb, and charges are also charged by the charging voltage Vb in the parasitic capacitor Cp, the driving capacitor Cdrv, and the common capacitor Cvcom. When the charge charged in the sensor pad 110 reaches the target voltage Vpc, the controller 240 turns off the transistor 211 by lowering the control signal Vg from the high voltage VH to the low voltage VL. Finish section T1. The touch detector 210 may include a comparator (not shown) to use the target voltage Vpc and the output voltage Vo as inputs of the comparator and use the output as a control signal Vg.

Referring to FIG. 6, when the charging period T1 starts and the transistor 211 is turned on, the voltage charged in the entire capacitor C is equal to V = Vb * e− ^{t / (R * C)} . R is a resistance value selected from the plurality of resistors R1 to R4, and C is a sum of capacitances of the parasitic capacitor Cp, the driving capacitor Cdrv, and the common capacitor Cvcom. If the charging voltage Vb is at a potential sufficiently larger than the target voltage Vpc, the time for reaching the target voltage Vpc may be shortened by the above equation.

For example, when the target voltage (Vpc) is 5V, when the charging voltage (Vb) is 10V (V2) than the charging voltage (Vb) is 5V (V2), the time to reach the target voltage (Vpc) is electronic Can be reduced to half the level. Accordingly, the touch detection speed can be increased. In addition, the waveform of the voltage V charged in the capacitor C may vary according to V3 according to a resistance value selected from the plurality of resistors R1 to Rn.

Therefore, when a malfunction occurs in a specific frequency band during touch detection, a resistance may be selected from a plurality of resistors R1 to Rn to enable the avoidance start of the malfunction band. In addition to the resistors V1 to Vn, the target voltage Vpc and the charging voltage Vb may be varied as necessary, thereby controlling the charge charging speed and the amount of current. When the charging voltage Vb is sufficiently high, the target voltage Vpc is increased to detect the relative strong current. If the strong current detection condition is established, the charging potential of the capacitor C is high when the touch is detected. It has a characteristic strong against radiation noise of the squeezed state.

Next, when the sensing period T2 is started while the control signal Vg is lowered 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 are performed. Capacitor Cdrv and common capacitor Cvcom are isolated in a charged state. In this case, in order to stably isolate the charged signal, the input terminal of the level shift detection unit 212 preferably has a high impedance, but the touch input is discharged while discharging the signal charged in the sensor pad 110 and the driving capacitor Cdrv. When the charging signal is isolated by other means, or when the charging signal can be quickly observed at the start of discharge, the impedance of the input terminal of the level shift detector 212 may be low.

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 0V to 5V, the output voltage Vo of the sensor pad 110 may increase momentarily, and at 5V again. When it drops to 0V, the level of the output voltage Vo drops instantaneously. This rise or fall in voltage levels is sometimes referred to as "kick-back."

When there is no touch on the sensor pad 110, that is, when the capacitor connected to the sensor pad 110 includes only the driving capacitor Cdrv and the parasitic capacitor Cp, the output voltage Vo by these capacitors Cdrv and Cp is present. The voltage variation of ΔVo is

[Equation 1]

. Where VdrvH and VdrvL are the high level voltage and the low level voltage of the alternating voltage Vdrv, respectively.

Next, a case in which the touch input tool is touched on the sensor pad 110 will be described. When a touch is generated, 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. In the same manner as described above, the charging voltage is charged by the charging voltage Vb in the charging period T3, and the voltage variation ΔVo of the sensor pad 110 by the three capacitors Cdrv, Cp, and Ct in the sensing period T4. ) Becomes the following [Equation 2].

&Quot; (2) "

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

In general, the capacitance C of the capacitor is proportional to the area A of the electrode and proportional to the distance d between the electrodes, that is, C = εA / d (ε is the dielectric constant). Therefore, as the touch area increases, the touch capacitance Ct increases. As illustrated in FIG. 5, when a change in the alternating voltage Vdrv applied to the driving capacitor Cdrv occurs in the sensing periods T2 and T4 where the transistor 211 is turned off, the output voltage Vo Voltage change occurs. By using such a relationship, whether or not the touch and the touch area may be calculated using the difference in the voltage variation ΔVo of the output voltage Vo before and after the touch.

Referring back to FIG. 4, the level shift detector 212 detects a level shift generated by an alternating voltage Vdrv in a floating state. In detail, the level shift detection unit 212 may include a change ΔVo of the output voltage Vo at the sensor pad 110 when no touch occurs and a change variance of the output voltage Vo at the sensor pad 110 when the touch occurs. [Delta] Vo) can be measured to detect whether a level shift has occurred. That is, the potential of the sensor pad 110 is raised or lowered by the applied alternating voltage Vdrv. The voltage level variation when the touch occurs is smaller than the voltage level variation when the touch does not occur. Therefore, the level shift detector 212 detects the level shift by comparing the output voltage Vo levels before and after the touch. In addition, the level shift detector 212 may acquire a touch signal based on the difference between the voltage variations.

The level shift detection unit 212 will now be described in more detail.

7 is a block diagram of a level shift detection unit according to an embodiment of the present invention.

7, the level shift detection unit 212 according to the present embodiment includes an amplification unit 2121, a buffer unit 2122, a reference voltage supply unit 2123, an analog-to-digital conversion unit (ADC) 2124, A level shift output section 2125, a level shift correction section 2126, and a noise correction section 2127. The level shift detector 212 may omit at least one of these elements as necessary. In addition, the level shift detection unit 212 may include a voltage to frequency converter (VFC), a flip-flop, a latch, and a transistor. (Transistor), a thin film transistor (Thin Film Transistor), it may be configured by combining at least one of a comparator.

The amplifier 2121 amplifies the output voltage Vo of the touch cell. The amplifier 2121 may be a differential amplifier, and two inputs of the differential amplifier may be an output voltage Vo of a touch cell and a reference voltage Vr of a reference cell, and the amplifier 2121 may have two voltages. The difference between Vo and Vr is amplified and the amplified voltage Vop is output.

As mentioned above, the touch cell includes the sensor pad 110, the signal wiring 120, the transistor 212, the driving capacitor Cdrv, and the parasitic capacitor Cp shown in FIG. 4, and when there is a touch. Refers to a conventional touch cell further including a touch capacitor Ct, and a reference cell refers to a touch cell that does not include a touch capacitor Ct because a user's touch does not occur.

The voltage difference (ΔV = Vr-Vo) between the output voltage Vo of the touch cell and the reference voltage Vr of the reference cell refers to the voltage difference when the alternating voltage Vdrv is the high voltage VdrvH. (ΔV) is equal to the difference (level shift) of the voltage variation ΔVo before and after the touch, and may be expressed as Equation 3 below.

&Quot; (3) "

Where ΔVr = Vr-Vb and ΔVo = Vo-Vb.

When the touch capacitance Ct is zero, that is, the voltage difference ΔV at the metric is 0, and as the touch capacitance Ct increases, the voltage difference ΔV also increases. Since the touch capacitance Ct is proportional to the touch area A and inversely proportional to the distance d between the touch means and the sensor pad 110, that is, since Ct = εA / d (ε is the dielectric constant), the distance d Is constant, the touch area A and the touch capacitance Ct are linearly proportional. Therefore, it can be understood that the larger the voltage difference? V, the larger the touch area A is.

The reference voltage provider 2123 may provide the reference voltage Vr to the amplifier 2121 in place of the reference cell. The reference voltage provider 2123 stores the digital value of the reference voltage Vr in the memory 230 for each sensor pad 110, reads the digital value, and then converts the analog reference voltage Vr to the differential amplifier through digital-to-analog conversion. Can provide. When the amplifying unit 2121 is a single input amplifier, the reference value providing unit 2123 may include a subtraction circuit, and the amplifying unit at the reference voltage Vr amplified to the same level as the amplifying ratio of the amplifying unit 2121. A value obtained by subtracting the amplification voltage Vop of 2121 may be output.

The buffer unit 2122 maintains the amplification voltage Vop and outputs it to the output voltage Vob so that the amplification voltage Vop from the amplifying unit 2121 is not changed. For example, the buffer unit 2122 may be a rail to rail. It may be a buffer.

The noise corrector 2127 removes a noise component introduced by the touch contact means from the output voltage Vob of the buffer unit 2122 and corrects the output voltage Vob of the buffer unit 2122.

Next, the noise correction unit 2127 will be described in more detail with reference to FIGS. 8 to 10.

FIG. 8 is an exemplary circuit diagram of the buffer unit 2122 and the noise correction unit 2127 shown in FIG. 7, FIG. 9 is a schematic diagram showing input / output signals by the circuit shown in FIG. 8, and FIG. 10 is FIG. It is a schematic diagram which shows the filtering process of the output signal of the circuit shown in the figure.

Referring to FIG. 8, the noise corrector 2127 includes two differential amplifiers 2127a and 2127b. The amplification voltage Vop of the amplifier 2121 is input to the buffer unit 2122, and the output voltage Vob of the buffer unit 2122 is connected to the + terminal of the differential amplifier 2127a and the − terminal of the differential amplifier 2127b. The tracking voltage Vtr is input to the negative terminal of the differential amplifier 2127a and the positive terminal of the differential amplifier 2127b. Accordingly, the differential amplifier 2127a amplifies a portion greater than the tracking voltage Vtr of the output voltage Vob of the buffer unit 2122 to output the voltage Vop, and the differential amplifier 2127b outputs the voltage Vop. The voltage Vom is output by inverting and amplifying a portion smaller than the tracking voltage Vtr.

As illustrated in FIG. 9, the noise correction unit 2127 has a tracking voltage Vtr such that the amplitude of the output signal Vo of the differential amplifier 2127a and the output signal Vom of the differential amplifier 2127b are substantially the same. Set. For example, the value obtained by subtracting the maximum value of the differential amplifier 2127b output signal Vom from the maximum value of the differential amplifier 2127a output signal Vo can be set to the tracking voltage Vtr value. By setting the tracking voltage Vtr as described above, the magnitudes of the + peak value and the − peak value of the output voltage Vob of the buffer unit 2122 are substantially the same based on the tracking voltage Vtr.

The noise correction unit 2127 may further include an analog or digital low pass filter, which is obtained by passing the output signal Vo of the differential amplifier 2127a and the output signal Vom of the differential amplifier 2127b through the low pass filter. The signals Vop 'and Vom' are added up. Then, as shown in FIG. 10, an output signal Vop '+ Vom' having a flat waveform similar to passing through the rectifier is obtained, which corresponds to a noise corrected level shift value.

4, when a touch input means such as a finger touches the sensor pad 110, human body radiation noise flows through the sensor pad 110, which affects the output voltage Vo, making it difficult to determine whether or not the touch is input. If the output voltage Vob of the buffer unit 2122 including the human body radiation noise is used as it is, as shown in the first waveform of FIG. 9, even if a touch occurs in the waveform below the tracking voltage Vtr, it may be determined as a metric value. It is also difficult to calculate the exact touch area. However, by inverting the lower part of the output voltage Vob of the buffer unit 2122 based on the tracking voltage Vtr and summing it with the upper part, the influence on noise can be eliminated and the accurate touch area can be calculated.

On the other hand, the amplifier 2121 of the level shift detector 212 according to the embodiment of the present invention may be omitted. In this case, the output voltage Vo of the sensor pad 110 is directly input to the buffer unit 2122, and the output voltage of the sensor pad 110 using the differential amplifiers 2127a and 2127b of the noise correction unit 2127. Vo) can be amplified. In addition, the reference cell may be amplified by the noise correction unit 2127, and the reference voltage Vr of the reference cell may be amplified, and the level shift may be calculated using the amplified output voltage Vo and the amplified reference voltage Vr. can do.

The analog-digital converter 2124 converts the analog signal used by the noise correction unit 2127 into a digital signal and outputs the digital signal. If necessary, the output signals (Vop, Vom) of the differential amplifier (2127a) and the differential amplifier (2127b) may be converted, or the sum signal (Vop + Vom) thereof may be converted, or the signal after the filtering process may be digitally converted. have. The analog-to-digital converter 2124 may divide the output signal of the noise corrector 2127 into four sections, and may assign a digital value of 2 bits in order of magnitude to each section. However, setting the digital value to 2 bits is just one example, and other bits such as 4 bits, 8 bits, and 10 bits may be possible.

In any way, for convenience of explanation, a value obtained by digitally converting the final output signal Vo '+ Vom' of the noise correction unit 2127 is referred to as a "level shift output value".

On the other hand, since the touch capacitance (Ct) value is located in the denominator in [Equation 3], the voltage difference ΔV before and after the touch increases as the value of the touch capacitance (Ct) increases, but does not have complete linearity. The level shift correction unit 2126 corrects the nonlinearity of the touch cell to correct the level shift output value so that the area according to the touch and the output value may be linearly related.

As an example, the level shift correction unit 2126 may include a table in which the level shift output value and the touch capacitance Ct value correspond one-to-one, and extract the touch capacitance Ct value corresponding to the level shift output value. Can be exported.

As another example, the level shift correction unit 2126 may divide the level shift output value into sections, generate a linear function in each section, and match the output value of the generated linear function with respect to each voltage difference ΔV.

As another method, linearity can be imparted between the voltage difference ΔV and the touch area A by applying a predetermined weight to the output of each voltage difference ΔV.

On the other hand, even if the relationship between the voltage difference ΔV and the touch area A is not a perfectly linear proportion, if the slope is sufficiently gentle to provide sufficient accuracy for calculating the area, it is treated as being substantially linear proportional, and the voltage is not treated without special correction. The difference ΔV can be used to calculate the touch area A. In this case, the level shift correction unit 2126 may be omitted from the level shift detection unit 212.

The level shift output unit 2125 outputs the value corrected by the level shift corrector 2126 and stores it in the memory 230.

As described above, according to the level shift detector 212 according to the embodiment of the present invention, it is possible to appropriately compensate for the noise input generated from the human body contact, and the level shift before and after the touch and the touch area A are linearly proportional . Therefore, using such a linear proportional relationship, the touch detection apparatus according to the embodiment of the present invention can detect a very accurate touch area and touch coordinates.

Next, an operation of detecting the touch area and the touch coordinates by the touch detection apparatus according to the exemplary embodiment of the present invention will be described in detail with reference to FIGS. 11 to 13.

11 is a block diagram of a touch information processor according to an embodiment of the present invention. FIG. 12 is a schematic diagram illustrating a structure of a memory in which information about a sensor pad is stored, and FIG. 13 is an invention. A flowchart illustrating a touch detection method according to an embodiment of the present invention.

As illustrated in FIG. 11, the touch information processor 220 according to an exemplary embodiment of the present invention may include a touch cell detector 221 for detecting a touch cell, and a touch area calculator for calculating a touch area of a touch cell in which a touch occurs. 222, and a touch coordinate calculator 223 for calculating touch coordinates using the calculated touch area.

The memory 230 illustrated in FIG. 12 may include, for example, a plurality of memory cells having an address corresponding to a touch cell (strictly speaking, the sensor pad 110 should be used as a touch cell for convenience of description). Each memory cell may store the level shift value ΔVD amplified, digitized, and corrected through the level shift detector 212.

As described above, the level shift value ΔVD stored in the memory 230 is linearly proportional to the touch area with respect to the sensor pad 110. Therefore, this level shift value [Delta] VD is treated the same as the touched digital area value. The level shift value ΔVD may have four values of 00, 01, 10, and 11, for example, when digitized to 2 bits. Here, 00 means no touch, and 11 means that the entire sensor pad 110 is touched and covered. As described above, the magnitude of the level shift value ΔVD corresponds to the magnitude of the touch area for one sensor pad 110.

12 shows memory cells of M11 to M54, which correspond to touch cells C11 to C54, respectively. If a touch occurs in the touch cells C11, C12, C21, C22, C34, and C44, memory cells M13, M14, M23, M24, M31, M32, M33, M41, and M42 corresponding to touch cells that have little or no touch. 00 is stored in M43, M51, M52, M53, and M54, and memory cells M11, M12, M21, M22, corresponding to touch cells C11, C12, C21, C22, C34, and C44 where touch is generated. In M34 and M44, digital values according to the contact area will be stored.

The touch information processor 220 may read the digital area values of the touch cells C11 to C54 from the memory 230 to determine the contact area and the contact location.

Referring to FIG. 13, the touch detection apparatus according to the present embodiment first detects a common voltage Vcom cycle of a display device on which the touch detection apparatus is mounted (S100). The touch detection apparatus may include a separate circuit for detecting the common voltage Vcom period. Alternatively, the touch detection apparatus may provide information about the common voltage Vcom such as the period and the rising (or falling) edge point of the common voltage Vcom. It may be provided from a display device.

The touch detection apparatus controls the timing of the alternating voltage Vdrv such that the rising and falling edges of the alternating voltage Vdrv are generated while the common voltage Vcom is a high voltage (or low voltage). In this way, it is possible to prevent the level shift caused by the alternating voltage Vdrv from being distorted by the common voltage Vcom.

Meanwhile, as described above, the common voltage Vcom may be used as the alternating voltage Vdrv of the touch detection apparatus, and in this case, a separate means for generating the alternating voltage Vdrv may be omitted. The period of the control signal Vg is determined according to the period of the common voltage Vcom. Preferably, as shown in FIG. 5, the period of the control signal Vg may be twice the period of the common voltage Vcom. . The timing of the control signal Vg is controlled so that the rising edge and the falling edge of the control signal Vg do not occur when the common voltage Vcom is the high voltage VdrvH.

The touch detection apparatus raises the control signal Vg from the low voltage VL to the high voltage VH while the charge signal Vb is raised, thereby turning on the transistor 211 to charge the sensor pad 110 with the charge signal Vb. Charge to (S110).

Then, the touch detection apparatus lowers the control signal Vg from the high voltage VH to the low voltage VL for each touch cell to make the sensor pad 110 in a floating state. Thereafter, when the common voltage Vcom rises from the low voltage VdrvL to the high voltage VdrvH, the output voltage Vo of the sensor pad 110 is measured to scan each sensor pad 110 in a predetermined order (S120). ).

The touch detection apparatus detects the level shift value ΔVD by amplifying the output voltage Vo and analog-to-digital conversion (S130). The detected level shift value ΔVD is recorded in the memory 230 corresponding to each touch cell.

It is determined whether the level shift value ΔVD is 0 (S140), and when it is 0, steps S110 to S130 are repeated (S140). That is, when the level shift value ΔVD is 0, the touch cell does not generate a touch and thus detects the level shift value ΔVD until a touch occurs.

If the level shift value ΔVD is not 0, the touch cell group including adjacent touch cells whose level shift value ΔVD is not 0 is extracted (S150). According to an embodiment of the present invention, since the sensor pads 110 are each implemented in an isolated matrix form, the sensor pads 110 provide a multi-touch sensing function. Therefore, when multi-touch occurs, it is necessary to group touch cells in which touch occurs in order to calculate respective touch areas and coordinates.

Next, the area of the touch area is calculated based on the level shift value ΔVD of the touch cell group (S160). As described above, since the level shift value ΔVD and the touch area are proportional to each other, the touch area may be calculated by summing the level shift value ΔVD in the touch cell group.

Next, the coordinates of the touch area are calculated from the calculated area of the touch area (S170). In the touch panel 100 according to the exemplary embodiment of the present invention, the sensor pad 110 has a polygonal shape with a uniform size, and is arranged in a matrix form. Therefore, each of the sensor pads 110 covers the display device in a state having a predetermined area and address. Therefore, the occupation area of the sensor pad 110 may be matched with the coordinates of the image display device.

If information on the touch occupancy area is calculated for each sensor pad 110 from the touch area calculated in step S170, the touch area distribution of the X-axis and Y-axis of the sensor pad matrix may be obtained. When the area center points of the X and Y axes are obtained based on the area distribution, touch coordinates corresponding to the center points of the entire touch area may be calculated. By using the structure of the touch panel 100 and the calculated touch area, touch coordinates can be calculated very accurately.

By repeating these steps (S110 to S170), it is possible to continuously detect whether or not the touch is performed, the touch area, and the touch coordinates.

14 is an exploded view of a touch detection device according to another embodiment of the present invention, FIG. 15 is a plan view illustrating a touch detection device according to another embodiment of the present invention, and FIGS. 16 and 17 are different from the present invention. Exemplary diagrams illustrating touch sensitivity according to touch of the touch detection apparatus according to the embodiment.

As shown in FIGS. 14 to 17, the touch detection apparatus according to the present embodiment includes a plurality of sensor pads and a plurality of sensor pads made of a transparent material disposed on the substrate 3015 and the substrate 3015, respectively. A touch panel 3001 having a signal wire 3120 and a driving device 3200 for driving the touch panel 3001 may be included. Here, the sensor pad may be repeatedly arranged in two unit columns UC1 and UC2 constituting one basic column BC, and the basic column BC is repeatedly arranged in the row direction (first direction). Can be.

In detail, the sensor pad may include a first sensor pad 3500 and a second sensor pad 3600.

The first sensor pad 3500 may extend in the column direction (second direction), and the first sensor pad 3500 may be symmetrically formed with respect to the center thereof.

That is, the first sensor pad 3500 has a first unit sensor pad 3501 formed so as to have an area wider from the center to one end, and a second unit sensor pad 3502 formed so as to have an area wider from the center to the other end thereof. The first unit sensor pad 3501 and the second unit sensor pad 3502 may be formed to be symmetrical to each other.

The first unit sensor pads 3501 and the second unit sensor pads 3502 may have a right triangle shape, and thus, the first sensor pad 3500 may have a pentagon shape.

The first sensor pad 3500 may be repeatedly arranged in two unit columns UC1 and UC2 constituting one basic column BC.

In addition, the first unit sensor pad 3500 of one unit column UC1 or UC2 constituting the basic column BC is one pair with the first unit sensor pad 3500 of the remaining unit column UC2 or UC1. It may be arranged to achieve.

Accordingly, the remaining unit rows disposed to form a pair with the first unit sensor pad 3501 or the second unit sensor pad 3502 of the first sensor pad 3500 of any one unit column UC1 or UC2 ( The second unit sensor pad 3502 or the first unit sensor pad 3501 of the first sensor pad 3500 of UC2 or UC1 may have a rectangular shape as a whole.

The second sensor pad 3600 may extend in a column direction, and at least one unit of the basic column BC in which the first sensor pad 3500 is disposed adjacent to the first sensor pad 3500. May be arranged in rows UC1 or UC2.

To this end, the second sensor pad 3600 may be formed in a shape corresponding to the first unit sensor pad 3501 or the second unit sensor pad 3502. For example, the second sensor pad 3600 may have a shape of a right triangle.

The second sensor pad 3600 is paired with the first unit sensor pad 3501 or the second unit sensor pad 3502 disposed in one unit column UC1 or UC2 of the basic column BC. This can be arranged in the other unit row (UC2 or UC1).

That is, the second sensor pads 3600 are disposed in the remaining spaces (empty spaces of the unit rows) that are paired with each other between the first sensor pads 3500, so that the first unit sensor pads 3501 of the first sensor pad 3500 are located. Or it may be paired with the second unit sensor pad 3502.

In addition, the second sensor of the remaining unit row (UC2 or UC1) arranged to form a pair with the first unit sensor pad (3501) or the second unit sensor pad (3502) of any one unit row (UC1 or UC2) The pad 3600 may also have a rectangular shape as a whole.

The basic column BC formed as described above may be repeatedly arranged in the row direction (first direction).

On the other hand, as shown in FIG. 16A, when a user touch is made at one point TP1, the first touch sensitivity TS1 is performed by the first unit sensor pad 3501 of the first sensor pad 3500. ) Can be obtained.

When the user's touch is made at the second point TP2, the second touch sensitivity TS2 is obtained by the first unit sensor pad 3501 of the second sensor pad 3600 and the first sensor pad 3500. Can be.

In addition, when the user's touch is made at the third point TP3, the third touch sensitivity TS3 is obtained by the first unit sensor pad 3501a of the second sensor pad 3600 and the first sensor pad 3500a. Can be.

When the user touches at the four points TP4, the second unit sensor pad 3502 of the first sensor pad 3500 and the first unit sensor pad 3501a of the first sensor pad 3500a may be touched. By this, the fourth touch sensitivity TS4 can be obtained.

That is, when the user touch is continuously made in the row direction in the section extending from the two points TP2 to the four points TP4, since the touch is made overlapping over the two sensor pads, each sensor pad in the corresponding section. It is possible to obtain a constant touch sensitivity corresponding to the maximum touch sensitivity obtained from.

Such touch sensitivity may be enabled since the influence on the touch sensitivity is not caused by one sensor pad, as shown in FIGS. 16B and 16C.

16 (b), when the distance d1 between the sensor pads 1100 is wide, the contact area becomes smaller as the spacing becomes larger, so that the change of the touch sensitivity becomes lower (about 20 %) It may be difficult to grasp the exact touch location.

In addition, as shown in FIG. 16C, when the distance d2 between the respective sensor pads 1100 is narrowed, the touch sensitivity can be secured to some extent (about 40%). As the number increases, the number of signal wires connecting the sensor pad 1100 and the driving device also increases. In other words, an increase in the number of signal wires increases parasitic capacitances (Coupling Cp and Parasitic Cp) generated between the signal wires, thereby degrading the touch sensitivity and reducing the accuracy of coordinate detection. In addition, as the number of signal wires increases, the number of channels in the driving device must also increase, so that the size of the driving device is inevitably increased, and the shape of the sensor pad must be inevitably changed in order to secure space for the arrangement of the signal wires. Cases may occur.

However, as shown in FIG. 16A, the first sensor pad 3500 is formed of the first unit sensor pad 3501 and the second unit sensor pad 3502, and pairs with each other in each unit row. In this case, the influence on the touch sensitivity may be reduced according to the distance between the sensor pads.

That is, the areas touched by the sensor pads 3500 and 3600 arranged in a pair are sensed to complement each other, thereby compensating for the deterioration of the touch sensitivity.

Therefore, the touch sensitivity can be stabilized, and through this, more accurate touch coordinates can be extracted.

In addition, since the two sensor pads 3500 and 3600 arranged in a pair play a complementary role to each other, the touch sensitivity may be compensated for.

Meanwhile, the areas of the first sensor pad 3500 and the second sensor pad 3600 which are provided closest to the driving device 3200 in each basic row BC are the remaining first sensor pad 3500 and the second sensor. It may be smaller than the area of the pad 3600.

That is, the first unit sensor pad (or the second unit sensor pad) and the second sensor of the first sensor pad 3500 provided in the row R1 closest to the driving device 3200 in each basic column BC. Since the pad 3600 has a lower resistance of the signal wire 3120 than other sensor pads, the pad 3600 may have little or no signal distortion, thereby ensuring sufficient touch sensitivity for extracting touch coordinates.

And, as shown in (a) of FIG. 17, as the unit sensor pads 3501 and 3502 or the unit sensor pads 3501 or 3502 and the sensor pad 3600 are configured in pairs, the touch is made to slide. In this case, linear touch sensitivity may be secured.

Securing such a linear touch sensitivity can provide more naturalness in signal transmission, for example, raising or lowering the volume.

That is, as shown in (b) of FIG. 17, when the sensor pads 1100 are individually disposed, a stepped touch sensitivity, that is, a non-linear touch sensitivity, may be secured when the touch is made to slide. As such, the above-described effects are hardly provided.

18 is an exemplary view comparing sensor pads of a touch detection apparatus according to another embodiment of the present invention.

As shown in FIG. 18, a virtual sensing area 110b may be formed including a portion of the first sensor pad 3500 and a portion of the second sensor pad 3600 adjacent to each other among the sensor pads.

The number of virtual sensing regions 1100b may be larger than the number of sensor pads (the first sensor pad 3500 and the second sensor pad 3600).

Here, the virtual sensing area 1100b may mean a sensing area of the sensor pad 1100 (see FIG. 16).

For example, as shown in FIG. 18, when there are six virtual sensing regions 1100b of the first sensor pad 3500 and the second sensor pad 3600, six virtual sensing regions 1100b may have six sensing regions. The sensor pad 1100 (see FIG. 16) is required.

Therefore, when six sensor pads 1100 (see Fig. 16) are arranged, it is assumed that six signal wirings 1120 However, in the embodiment of the present invention, four signal lines 3120 may be required.

That is, in this case, the number of signal wires 3120 can be reduced to 2/3.

Of course, if the virtual sensing area formed by appropriately adjusting the areas of the first sensor pad 3500 and the second sensor pad 3600 is increased, the number of signal wires may be further reduced.

As the number of signal wires 3120 decreases, the size of the driving device 3200 (see FIG. 15) may also be reduced, which may provide further advantages when mounting the circuit board 3250 (see FIG. 15).

In addition, as the number of signal wires 3120 decreases, the influence of parasitic capacitance generated between adjacent signal wires 3120 may be reduced, and the touch sensitivity may be improved.

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. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

10,3010: insulating film 15,3015: substrate
20,3250: circuit board 100,3001: touch panel
110, 1100: sensor pads 120, 1120, 3120: signal wiring
200, 3200: driving device 210: touch detection unit
212: transistor 212: level shift detector
2121: amplifier 2122: buffer
2123: reference value providing unit 2124: analog-to-digital conversion unit
2125: level shift output section 2126: level shift correction section
2127: noise correction unit 220: touch information processing unit
221: touch cell detector 222: touch area calculator
223: touch coordinate calculator 230: memory
240: control unit 3500: first sensor pad
3501: first unit sensor pad 3502: second unit sensor pad
3600: second sensor pad

Claims (8)

A touch panel having a substrate, a plurality of sensor pads of a transparent material disposed on the substrate, and a plurality of signal wires respectively connected to the sensor pads; And
It includes a drive device for driving the touch panel,
The sensor pad is repeatedly disposed in two unit columns constituting one basic column, and the basic column is repeatedly arranged in a row direction. The method of claim 1,
The sensor pad is
A first sensor pad extending in a column direction and symmetrically formed with respect to a center thereof and repeatedly disposed in the two unit rows in the one basic column;
And a second sensor pad extending in a column direction and disposed in at least one unit column of the basic column in which the first sensor pad is disposed adjacent to the first sensor pad. 3. The method of claim 2,
The first sensor pad has a first unit sensor pad formed to have an area wider from the center to one end, and a second unit sensor pad formed to have an area wider from the center to the other end. The method of claim 3,
The second sensor pad may be formed in a shape corresponding to the first unit sensor pad or the second unit sensor pad, and the first sensor pad or the second unit sensor pad may be disposed in one unit row. Touch detection device that is arranged in pairs of the remaining one unit column. 3. The method of claim 2,
The first sensor pad has a pentagonal shape, and the second sensor pad has a right triangle shape. 3. The method of claim 2,
And the area of the first sensor pad and the second sensor pad provided closest to the driving device in each of the basic rows is smaller than the area of the remaining first sensor pad and the second sensor pad. A substrate, a touch panel having a plurality of sensor pads of a transparent material disposed on the substrate, a plurality of signal wires connected to the sensor pads, and a driving device for driving the touch panel,
And a region of a portion of the first sensor pad and a portion of the second sensor pad adjacent to each other among the sensor pads to form a virtual sensing region. The method of claim 7, wherein
The number of the virtual sensing area is greater than the number of sensor pads.

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