WO2013183917A1

WO2013183917A1 - Touch detection method and apparatus

Info

Publication number: WO2013183917A1
Application number: PCT/KR2013/004925
Authority: WO
Inventors: 손영석; 이제혁; 이승은
Original assignee: 크루셜텍 주식회사
Priority date: 2012-06-04
Filing date: 2013-06-04
Publication date: 2013-12-12

Abstract

A touch detection method of a touch panel that includes sensor pads separated from each other, which is provided according to one embodiment of the present invention, comprises: a step of selecting a plurality of sensor pads; a step of charging the selected plurality of sensor pads and acquiring simultaneously signals outputted in response to the alternating voltage supplied in a floating state; and a step of converting the outputted signals simultaneously acquired from the plurality of sensor pads into digital signals.

Description

Touch detection method and device

The present invention relates to a touch detection method and apparatus, and more particularly, to a method and apparatus for reducing the touch detection time by simultaneously obtaining a signal output from a plurality of touch sensors and necessary to determine whether or not the touch.

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 the image display device. The touch screen panel converts a contact position touched by a human finger or the like into an electrical signal. The electrical signal is used as an input signal.

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.

For the capacitance measurement of one sensor pad 22, the precharging time for the sensor pad 22, the time until the voltage change returns to the normal state when the driving voltage is applied in the floating state after precharging, and the signal conversion And a time for determining whether a touch occurs.

Conventionally, since only one sensor pad 22 can be detected as a touch occurs at a time, a lot of time is required for detecting whether a touch occurs with respect to all the sensor pads 22.

The present invention aims to solve the above-mentioned problems of the prior art.

Another object of the present invention is to reduce a touch detection time while maintaining a conventional structure in a touch panel including a plurality of sensor pads arranged in isolation.

According to an embodiment of the present invention for achieving the above object, a touch detection method of a touch panel including a sensor pad is isolated from each other, comprising: selecting a plurality of sensor pads; Acquiring signals output in response to an alternating voltage supplied in a floating state after charging the plurality of selected sensor pads; And sequentially converting output signals simultaneously obtained from the plurality of sensor pads into digital signals.

The selecting of the plurality of sensor pads may include selecting one sensor pad by a plurality of multiplexers connected to one or more sensor pads through signal wires.

The sensor pads may be arranged in a matrix form of M × N, and the plurality of multiplexers may be implemented as N multiplexers connected to M sensor pads, respectively.

Signals acquired simultaneously from the plurality of selected sensor pads may be sequentially input to an analog-to-digital converter that performs the conversion by a multiplexer.

The method may further include detecting whether or not the touch is performed based on a difference in voltage variation in the sensor pad according to the alternating voltage when the touch is not generated and when the converted signal is generated.

On the other hand, according to another embodiment of the present invention, a touch detection device of a touch panel including sensor pads are isolated from each other, comprising: a plurality of first multiplexers for selecting a plurality of sensor pads, respectively; A second multiplexer simultaneously receiving a signal output in response to an alternating voltage supplied in a floating state after charging of the plurality of sensor pads selected by the first multiplexer; And an analog-digital converter for converting a signal sequentially output from the second multiplexer into a digital signal.

The sensor pads may be arranged in a matrix form of M × N, and the first multiplexers may be implemented in N and connected to M sensor pads, respectively.

The touch detection apparatus may further include a level shift detector configured to detect whether or not a touch is generated based on a difference in voltage variation in the sensor pad according to the alternating voltage when the touch is not generated and when the converted signal is generated.

According to the present invention, in a touch panel including a plurality of sensor pads disposed in isolation, signals required for touch detection can be simultaneously acquired from the plurality of sensor pads, thereby reducing the time required for touch detection for the entire touch panel. It can be greatly reduced.

1 is an exploded plan view of a conventional touch panel.

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

3 is a block diagram for explaining the configuration of a touch detection apparatus.

4 is a circuit diagram for describing a detailed internal configuration of a touch detection device.

5 is a circuit diagram for describing a driving circuit of the touch detection device.

6 is an exemplary waveform diagram for describing an operation of the touch detection device.

7 is a waveform diagram illustrating a change in voltage of a sensor pad output terminal over time during a touch detection process.

8 is a flowchart illustrating a touch detection method according to an embodiment of the present invention.

DETAILED DESCRIPTION The following detailed description of the invention refers to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be embodied in other embodiments without departing from the spirit and scope of the invention with respect to one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. Like reference numerals in the drawings refer to the same or similar functions throughout the several aspects.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

[Preferred Embodiments of the Invention]

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

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.

Referring to FIG. 4, the operation of the touch detector 210 will be described in detail.

Referring to FIG. 4, the touch detector 210 may include as many first multiplexers MUX1 as the number of columns of the sensor pads 110 that are separated from each other in a matrix form. In FIG. 4, an example in which M × N sensor pads 110 are arranged in a matrix form is illustrated. Accordingly, N first multiplexers MUX1 corresponding to the number of columns of the sensor pads 110 are provided.

One first multiplexer MUX1 selects one of the M signal wires 120 connected to the M sensor pads 110 belonging to one column. The signal related to the selection may be applied from the controller 240.

The output signal of the sensor pad 110 connected to the selected signal line 120 is input to the second multiplexer MUX2. The output signal of the sensor pad 110 may be output by the operation of the driving circuit 211.

The second multiplexer MUX2 selects one of the N first multiplexers MUX1 and transfers the output signal of the specific sensor pad 110 output from the selected first multiplexer MUX1 to the analog-to-digital converter ADC. do.

That is, a signal output from one sensor pad 110 selected by the first multiplexer MUX1 and the second multiplexer MUX2 is input to the analog-to-digital converter ADC. The analog-to-digital converter ADC may convert, amplify, or digitize a signal output from the sensor pad 110, that is, a voltage change difference, and store the same in the memory unit 230 (see FIG. 3).

FIG. 5 is a circuit diagram illustrating the configuration of the driving circuit 211 of the touch detector 210 in detail, and FIG. 6 is an exemplary waveform diagram of the touch detector 210 for explaining the operation of the driving circuit 211.

Referring to FIG. 5, the driving circuit 211 is connected to the sensor pad 110 through the signal wire 120, and performs a switching operation Ts, a parasitic capacitor Cp, a driving capacitor Cdrv, It includes a common voltage capacitor (Cvcom).

The transistor Ts, the parasitic capacitor Cp, the driving capacitor Cdrv, and the common voltage capacitor Cvcom may be grouped one per sensor pad 110 and the signal wire 120, and in the future, the sensor pad 110, The signal wiring 120, the transistor Ts, 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.

In FIG. 5, the signal wire 120 is illustrated as being directly connected between the driving circuit 211 and the sensor pad 110, but the signal wire 120 includes a plurality of signal wires connected to the plurality of sensor pads 110, respectively. 120 may be one selected by the first multiplexer MUX1 (see FIG. 4).

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".

Hereinafter, for convenience, the reference numerals of the capacitor and its capacitance are used the same.

The transistor Ts 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 instead of the transistor Ts may be used.

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 that it is contained 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 alternate 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. 5, 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. 6, the charging signal Vb and the control signal Vg are applied to the source and gate of the transistor Ts, 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 Ts rises from the low voltage VL to the high voltage VH, the transistor Ts is turned on and the first charge is turned on. The section 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. Since the transistor Ts is turned on in the first charging period T1, the alternating voltage Vdrv does not affect the output voltage Vo.

Next, when the first sensing period T2 is started while the control signal Vg goes from the high voltage VH to the low voltage VL, the transistor Ts is turned off, the touch capacitor Ct and the parasitic capacitor Cp. The driving capacitor Cdrv and the common voltage capacitor Cvcom are isolated in a charged state. In this case, the output terminal of the sensor pad 110 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 falls, the voltage Vo level at the output terminal of the sensor pad 110 may drop instantaneously. In addition, as in the second detection period T4, when the alternating voltage Vdrv increases in the floating state of the sensor pad 110, the voltage Vo level at the output terminal of the sensor pad 110 rises momentarily. . At this time, the rise and fall of the voltage (Vo) level has a different value according to the connected capacitance. The rising or falling value of the voltage level according to the connected capacitance is also called a "kick-back".

When there is no touch on the sensor pad 110, that is, when only the capacitor Cdrv and the parasitic capacitor Cp are connected to the sensor pad 110, the output voltage Vo by these capacitors Cdrv and Cp is applied. The voltage variation ΔVo1 is equal to the following Equation 1.

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 the 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. In the same manner as described above, 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.

Equation 2

Comparing

Equations

1 and 2, since the touch capacitance Ct is added to the denominator item of Equation 2, the voltage variation ΔVo2 in the case of the touch is the result of the voltage variation in the case of no touch ( Small compared to ΔVo1), 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." In the present specification, "level shift" may also mean a digital value of a voltage difference ΔVo.

If the touch input does not occur in the second detection period T ₄ , the voltage level Vo at the output terminal of the sensor pad 110 is changed from 5 V to 7.5 V according to Equation 1, but the touch input occurs. Accordingly, the voltage level Vo at the output terminal of the sensor pad 110 is 6V. That is, it can be seen that the voltage level Vo at the output terminal of the sensor pad 110 at the time of touch generation is shifted from 7.5V to 6V as compared to when no touch occurs. Therefore, such a level shift can be detected to obtain a touch signal.

In the third charging process T ₅ , the voltage Vo at the output terminal of the sensor pad 110 becomes 5V again, and in the third detection process T ₆ , the touch input is generated and thus the voltage of the alternating voltage Vdrv. In this case, the output terminal voltage Vo level of the sensor pad 110 drops to 3.33V according to Equation 2. That is, when the touch input occurs, the voltage Vo is shifted downward in the rising section of the alternating voltage Vdrv and the voltage Vo is shifted upward in the falling section of the alternating voltage Vdrv.

On the other hand, the capacitance C of the capacitor is C = ε * A / d, which is proportional to the area A of the electrode and inversely proportional to the distance d between the electrodes (ε is a dielectric constant). Therefore, as the touch area increases, the touch capacitance Ct increases. As shown in FIG. 6, when a variation of the alternating voltage Vdrv applied to the driving capacitor Cdrv occurs in the sensing periods T ₂ , T ₄ , and T _{6 in} which the transistor Ts is turned off, the output The voltage change of the voltage Vo occurs. By using such a relationship, whether or not the touch and the touch area may be calculated by using the difference ΔVo1-ΔVo2 of the voltage variation ΔVo of the output voltage Vo before and after the touch.

4 and 5, the level shift generated by the alternating voltage Vdrv in the floating state can be detected from the output terminal voltage Vo of the sensor pad 110. A level shift detector (not shown) for detecting such a level shift may be additionally provided in the touch detector 210. Specifically, the output terminal voltage Vo of the sensor pad 110 may be converted into a digital signal by an analog-to-digital converter ADC, and the level shift detection unit outputs the voltage at the sensor pad 110 when no touch occurs. The variation ΔVo1 of Vo and the variation ΔVo2 of the output voltage Vo at the sensor pad 110 at the touch occurrence may 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 in the case of touch is smaller than the voltage level variation in the case of no touch. Therefore, the level shift detector may detect the level shift by comparing the output voltage Vo level immediately after the alternating voltage Vdrv rises in the floating state. In this case, if the level shift value is not 0, a touch has occurred, and thus the level shift value can be used as a touch signal. On the other hand, when the alternating voltage Vdrv falls first in the floating state, the level shift may be detected by comparing the output voltage Vo level immediately after the fall.

In the touch detection apparatus illustrated in FIG. 4, in order to perform touch detection on M × N sensor pads 110, the charging time of each sensor pad 110, the stabilization time when a kickback phenomenon occurs, and the signal conversion time are need. That is, an operation of performing touch detection on one sensor pad 110 selected by the first multiplexer MUX1 and the second multiplex MUX2, and then performing touch detection on another sensor pad 110. This must happen sequentially.

FIG. 7 is a diagram illustrating a change in voltage of the output terminal of the sensor pad 110 when detecting the touch with respect to the sensor pad 110. FIG. 7 illustrates a time required for touch detection of one sensor pad 110.

Referring to FIG. 7, in order to detect a touch of one sensor pad 110, a time Ta until a kickback phenomenon occurs after charging and floating the sensor pad 110 and a sensor pad 110 when kickback occurs. A time Tb for the output stage voltage to return to a normal state, a time Tc converted into a digital signal and a level shift is detected is required.

In order to detect the touch of the sensor pad 110, a process of floating after charging and a kickback state according to an alternating voltage Vdrv in the floating state are required. After the charging and plotting, it is assumed that the time until the kickback is observed according to the change of the alternating voltage (Vdrv) is assumed to be Ta.

On the other hand, in the floating state of the sensor pad 110, that is, in the sensing period, when the alternating voltage Vdrv falls, a kickback occurs in which the output voltage of the sensor pad 110 decreases. You need some time to get back. Since the minimum time required is five times the value of the time constant τ expressed as the product of the total resistance R and the total capacitance C viewed from the output terminal of the sensor pad 110, a time of at least 5 τ is required. The time Tc converted into a digital signal and whether or not a touch is determined is a time at which a level shift is detected by the level shift detector after the analog signal is converted into a digital signal by the analog-to-digital converter ADC (see FIG. 4).

Since a time of Ta + Tb + Tc is required for touch detection on one sensor pad 110, M × N × (Ta + Tb + for touch detection on a touch panel including two sensor pads 110. The time of Tc) is required.

After charging and plotting the sensor pad 110, the time Ta until immediately before the kickback is about 10 ms, and the signal shift time by the analog-to-digital converter ADC and the level shift detection time Tc by the level shift detection unit are about 2. We can assume that In addition, the time Tb to return to the normal state when the kickback occurs is longer as the sensor pad 110 is farther from the touch detector 210 (see FIG. 4). Assuming that the sensor pad 110 closest to the touch detector 210 is 10 ms and the furthest sensor pad 110 is 50 ms, the average value of the sensor pad 110 is calculated for the touch detection for the entire sensor pad 110. Can be used as a variable.

That is, the time required for detecting the touch on the touch panel including the M × N sensor pads 110 is expressed by Equation 3 below.

Equation 3

In the present invention, the following touch detection method is used to reduce the touch detection time.

4 and 8, in the touch panel 100 including M × N sensor pads 110, each of the M sensor pads 110 belonging to one column is connected to each other through the signal wire 120. Is connected to the first multiplexer (MUX1). In FIG. 4, it is illustrated that one first multiplexer MUX1 is connected to the sensor pads 110 included in one column through the signal wire 120, but the present invention is not limited thereto and the first multiplexer MUX1 may be one. The sensor pads 110 may be connected to the sensor pads 110 included in the row, or alternatively, the sensor pads 110 may be randomly selected. That is, the first multiplexer MUX1 may be connected to the plurality of sensor pads 110 through the signal wire 120. In the following description, it is assumed that the first multiplexer MUX1 is connected to the sensor pads 110 belonging to one column.

In this case, the first multiplexer MUX1 is provided by the number of rows of the sensor pads 110 arranged in a matrix form of M × N. In the example illustrated in FIG. 4, N first multiplexers MUX1 may be provided.

Each first multiplexer MUX1 selects one of the M signal wires 120 connected to the M sensor pads 110. That is, the first multiplexer MUX1 selects one of the M channels, so that all N first multiplexers MUX1 can select one sensor pad 110 (S810).

After charging the N sensor pads 110 selected by each of the N first multiplexers MUX1 at the same time, an alternating voltage of which the level varies at a predetermined period is applied while maintaining the floating state (S820).

When the alternating voltage is applied, a kickback phenomenon occurs according to the alternating voltage level change, and thus the output terminal voltage value of the sensor pad 110 is input to the second multiplexer MUX2. Since the kickback phenomenon due to the charging, floating, and alternating voltage applied to the sensor pad 110 is the same as described with reference to FIGS. 5 and 6, a detailed description thereof will be omitted. Since one output terminal voltage value of one sensor pad 110 per one multiplexer MUX1 is input to the second multiplexer MUX2, a total of N sensor pad 110 output terminal voltage values are input to the second multiplexer MUX2. It becomes (S830).

The N sensor pad 110 output terminal voltage values input to the second multiplexer MUX2 are output one by one and converted into digital signals by the analog-to-digital converter ADC (S840). The converted signal is used by the level shift detection unit to detect the level shift and determine whether a touch to the corresponding sensor pad 110 is generated (S850). That is, the N sensor pad 110 output terminal voltages are sequentially converted into digital signals, and used for level shift detection and determination of touch generation.

Level shift detection and a method of determining whether a touch is generated through the same are the same as those described with reference to FIGS. 5 and 6, and thus a detailed description thereof will be omitted.

According to the touch detection method, the charging process for the N sensor pads 110 at once and the process of applying the alternating voltage after the floating and acquiring the output voltage variation value according to the same are simultaneously performed, so that the touch for the entire touch panel 100 is performed. The time required for the detection process is reduced.

Specifically, the time before the kickback phenomenon occurs after charging and plotting the sensor pad 110 is Ta, and when the kickback occurs, the time for the output terminal voltage of the sensor pad 110 to return to a normal state is converted into a digital signal Tb. If the time at which the level shift is detected is Tc, the touch detection time for the entire touch panel 100 including M × N sensor pads 110 is (Ta + Tb + N * Tc) × M, and Ta, Substituting the values given in Equation 3 into Tb and Tc results in Equation 4 below.

Equation 4

Comparing Equation 3 and Equation 4, when using the touch detection method according to the present invention, time by M (N-1) {10-1 + (50㎲ + 10㎲) / 2} can be reduced. have.

Table 1 below is a table comparing the touch detection time between the conventional touch detection method and the touch detection method according to an embodiment of the present invention.

Table 1

	240 Channel Case		390 Channel Case		unit
	Old way	Inventive method	Old way	Inventive method
N
	12	12	15	15	ea
M
	20	20	26	26	ea
Pre setting time	10	10	10	10	㎲
Settling time 1st row	50	50	65	65	㎲
Settling time Nth row	10	10	10	10	㎲
ADC time
	2	2	2	2	㎲
One frame sensing time	10.08	1.28	19.305	2.015	㎳
Frame rate	99	781	52	496	Hz

The case of 240 sensor pads 110 and the case of 390 sensor cases 110 were assumed, respectively. In the table, " Pre setting time " and " ADC time " are variables respectively meaning Ta and Tc in FIG. In addition, "Settling time 1st row" is a time corresponding to Tb of the sensor pad 110 farthest from the first multiplexer MUX1 of the touch detector 210, and "Settling time Nts row" is the touch detector 210. Is the time corresponding to Tb for the sensor pad 110 that is closest to the first multiplexer MUX1.

On the other hand, "One frame sensing time" refers to the time required for the touch detection for the entire touch panel, "Frame rate" represents the number of times the touch can be detected for the touch panel per second.

As can be seen in Table 1, M sensor pads 110 are grouped and charged at the same time and then floated, and by simultaneously acquiring the output voltages of the sensor pads 110 according to alternating voltages, the entire touch panel 100 Touch detection time has been drastically reduced.

Embodiments according to the present invention described above can be implemented in the form of program instructions that can be executed by various computer components and recorded on a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the computer-readable recording medium may be those specially designed and configured for the present invention, or may be known and available to those skilled in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs, DVDs, and magneto-optical media such as floptical disks. media), and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform the process according to the invention, and vice versa.

Although the present invention has been described by specific embodiments such as specific components and the like, but the embodiments and the drawings are provided to assist in a more general understanding of the present invention, the present invention is not limited to the above embodiments. For those skilled in the art, various modifications and variations can be made from these descriptions.

Therefore, the spirit of the present invention should not be limited to the embodiments described above, and all of the equivalents or equivalents of the claims, as well as the claims below, are included in the scope of the spirit of the present invention. I will say.

Claims

In the touch detection method of the touch panel comprising a sensor pad is isolated from each other,

Selecting a plurality of sensor pads;

Acquiring signals output in response to an alternating voltage supplied in a floating state after charging the plurality of selected sensor pads; And

And sequentially converting output signals simultaneously acquired from the plurality of sensor pads into digital signals.
The method of claim 1,

The selecting of the plurality of sensor pads may include:

And selecting one sensor pad by a plurality of multiplexers connected through one or more sensor pads through signal wires.
The method of claim 2,

The sensor pads are arranged in a matrix form of M × N, and the plurality of multiplexers are implemented as N multiplexers connected to M sensor pads, respectively.
The method of claim 1,

And the signals acquired simultaneously from the plurality of selected sensor pads are sequentially input to an analog-to-digital converter for performing the conversion by one multiplexer.
The method of claim 1,

And detecting whether or not the touch is performed based on a difference in voltage variation in the sensor pad according to the alternating voltage when the touch is not generated and at the occurrence of the converted signal.
In the touch detection device of the touch panel including a sensor pad is isolated from each other,

A plurality of first multiplexers each selecting a plurality of sensor pads;

A second multiplexer simultaneously receiving a signal output in response to an alternating voltage supplied in a floating state after charging of the plurality of sensor pads selected by the first multiplexer; And

And an analog-to-digital converter for converting signals sequentially output from the second multiplexer into digital signals.
The method of claim 6,

The sensor pads may be arranged in a matrix form of M × N, and the first multiplexer may be implemented in N and connected to M sensor pads, respectively.
The method of claim 6,

And a level shift detector configured to detect whether or not a touch is generated based on a difference in voltage variation in the sensor pad according to the alternating voltage when the touch is not generated and when the converted signal is generated.