KR20130136374A - Touch detecting apparatus and method - Google Patents

Abstract

A touch detecting device according to an embodiment of the present invention includes a current flow control unit for charging a certain sensor node with electronic charges among multiple sensor nodes and supplying micro currents; a driving unit for applying alternative voltage to the sensor node in the micro current supply section; and a detection unit for detecting touches based on the voltage at an output end of the sensor node with the applied alternative voltage in the micro current supply section.

Description

Touch detection device and method {TOUCH DETECTING APPARATUS AND METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting a touch, and more particularly, to a touch detection apparatus and method for solving instability in a floating state.

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

As a method of implementing a touch screen panel, a resistive film method, a light sensing method, and a capacitive method are known. Among them, the capacitive touch panel converts the contact position into an electrical signal by sensing a change in the capacitance that the conductive sensing pattern forms with other peripheral sensing patterns or the ground electrode when a human hand or an object touches.

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

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.

The touch detection apparatus shown in FIGS. 1 and 2 can detect whether a touch is generated at a corresponding point through a change amount of an output voltage generated by applying an alternating voltage to a sensor node or a sensor pad in a floating state after precharging.

However, since the floating state is vulnerable to external noise, there is a problem that it is difficult to accurately detect the touch with accuracy.

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

Another object of the present invention is to solve the instability in the floating state after the charge for the touch detection.

In order to accomplish the above object, an embodiment of the present invention provides a sensor node comprising: a current flow controller for charging a specific sensor node among a plurality of sensor nodes and supplying a minute current; A driver for applying an alternating voltage to the sensor node in the minute current supply period; And a detecting unit for detecting whether or not the sensor is touched based on an output terminal voltage of the sensor node according to the alternating voltage application during the minute current supply period.

According to an embodiment of the present invention, the current flow control unit includes a current control switch for directly connecting the sensor node and the charging voltage supply terminal, or selectively connecting the sensor node and the charging voltage supply end through a selected one of a plurality of resistors .

According to an embodiment of the present invention, when the current control switch directly connects the sensor node and the charge voltage supply terminal, the sensor node is charged with electric charge, and the current control switch is connected to one of the plurality of resistors When the resistance is selected and the sensor node and the charging voltage supply terminal are connected through the selected resistance, the microcurrent may be supplied to the sensor node.

According to an embodiment of the present invention, the current control switch selects a resistance having a lower resistance value as the sensor node is disposed farther from the driving apparatus driving the plurality of sensor nodes at the time of supplying the fine current .

According to an embodiment of the present invention, the detection unit may perform touch detection by comparing the change of the output terminal voltage of the sensor node according to the application of the alternating voltage to the reference current.

According to an embodiment of the present invention, the sensor node further includes a sample-and-hold unit that samples and accumulates an output terminal voltage of the sensor node, and the detector compares the voltage stored in the sample-and- can do.

According to an embodiment of the present invention, the sample and hold unit may sample the output terminal voltage of the sensor node only during the minute current supply period, and then accumulate the voltage.

Another embodiment of the present invention provides a method for controlling a sensor node, comprising: charging a specific sensor node among a plurality of sensor nodes; Supplying a fine current to the sensor node; Applying an alternating voltage to the sensor node during the minute current supply period; And detecting whether or not the sensor is touched based on an output terminal voltage of the sensor node according to the alternating voltage application during the minute current supplying period.

According to another embodiment of the present invention, the charging step includes directly connecting the sensor node and the charging voltage supply terminal, wherein the fine current supplying step includes: And connecting the sensor node to the charging voltage supply terminal.

According to another embodiment of the present invention, the fine current supply step includes a step of selecting a resistance having a lower resistance value as the sensor node is disposed far away from the driving apparatus driving the plurality of sensor nodes .

According to another embodiment of the present invention, the detecting step may include performing touch detection by comparing the output terminal voltage change of the sensor node according to the alternating voltage application to the fine current supplying section with a reference value.

According to another embodiment of the present invention, the detecting step comprises the steps of: sampling the output terminal voltage of the sensor node and accumulating the voltage; And comparing the accumulated voltage with a reference value to detect whether or not the touch is detected.

According to another embodiment of the present invention, the accumulating step may include sampling the output terminal voltage of the sensor node only after the microcurrent supply period.

According to an embodiment of the present invention, it is possible to detect whether a touch is made based on an output terminal voltage of a sensor node when a fine current is supplied after charging for touch detection and an alternating voltage is applied.

This makes it possible to compensate for the vulnerability in a situation where touch detection is performed only by applying the alternating voltage in the floating state.

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

1 is an exploded plan view of an example of a capacitive touch screen panel according to the related art.
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 an exemplary waveform diagram for explaining the operation of the touch detection apparatus.
6 is a circuit diagram for explaining a configuration of a touch detection unit in a touch detection apparatus according to an embodiment of the present invention.
7 is an exemplary waveform diagram of a touch detection unit according to an embodiment of the present invention.
8 is a circuit diagram for explaining a configuration of a touch detection unit in 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.

In the present specification, the 'sensor node' may be referred to as a unit area for sensing whether or not the touch panel is touching the electrostatic touch screen panel. For example, a sensor node may include a plurality of sensor pads arranged in an isolated form in a self-capacitance type touch screen panel for measuring the capacitance of one sensor pad, A mutual capacitance type touch screen panel using capacitances between the driving lines Tx to which the driving signals are applied and the sensing lines Rx that provide signal sensing points for touch detection, Region. ≪ / RTI >

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

Hereinafter, a sensor pad in a self-capacitance type touch screen panel will be described as an example, but the present invention is also applicable to a sensor node in a mutual capacitance type touch screen panel.

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 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.

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

FIG. 4 is a circuit diagram illustrating a touch detection unit according to an embodiment, and FIG. 5 is an exemplary waveform diagram of a touch detection unit according to an embodiment.

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

The transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, the common voltage capacitor Cvcom and the level shift detection unit 212 can be grouped into one for each sensor pad 110 and the signal wiring 120, The sensor pad 110, the signal line 120, the transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, and the common voltage capacitor Cvcom are collectively referred to as a "touch sensing unit" . This touch sensing unit is a concept that includes the case where each component is electrically connected by a multiplexer.

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

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

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

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

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

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

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

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

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

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

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

When there is no touch on the sensor pad 110, that is, when only the driving 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 of ΔVo1 is expressed by Equation 1 below.

[Equation 1]

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

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

&Quot; (2) "

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

Therefore, the variation? Vol1 of the output voltage Vo at the sensor pad 110 and the variation? Vo2 of the output voltage Vo at the sensor pad 110 at the time of occurrence of the touch are measured, It is possible to detect whether or not the touch is generated.

In order to detect the level shift, it is necessary to apply an alternating voltage (Vdrv) in the floating state as described above. Since the charge is isolated, the floating state is a very unstable state. In order to stably maintain the floating state, it is possible to use a method of maintaining the output terminal of the sensor pad 110 at a high impedance (High-Z) as shown in FIG. 4, but it is also free from the influence of external noises It is not a state.

Therefore, in order to solve the instability of the floating state, the touch detection unit 210 is implemented in a different form in the present invention. Hereinafter, the structure and operation of the touch detection unit 210 will be described in detail.

6 is a circuit diagram showing a configuration of a touch detection unit 210 in a touch detection apparatus according to an embodiment of the present invention.

Referring to FIG. 6, the touch detection unit 210 may include a current flow controller 213, a driver 214, and a sample and hold unit 215.

The current flow controller 213 charges the sensor pad 110 with electric charge, and then supplies a minute current. To this end, the current flow controller 213 includes a current control switch SW that directly connects the charge voltage supply terminal and the sensor pad 110 or selectively connects the resistor through a selected one of a plurality of resistors.

The current control switch SW may be implemented by a mechanical switch as shown in the figure, but is not limited thereto.

The sensor pad 110 may be selectively connected to a plurality of nodes connected to the charge voltage supply terminal by a current control switch SW. One of the plurality of nodes may be directly connected to the charge voltage supply terminal and the remaining node may be connected to the charge voltage supply terminal through a predetermined resistor R1, R2, R3, ..., Rn.

7 is an exemplary waveform diagram of a touch detection unit according to an embodiment of the present invention.

Hereinafter, the operation of the touch detection unit 210 will be described in detail with reference to FIG. 6 and FIG.

The current control switch SW of the current flow controller 213 directly connects the sensor pad 110 to the charging voltage supply terminal and the sensor pad 110 is connected to the charging voltage supply terminal, The charge is charged. Assuming that the charging voltage Vpre_charge is 5 V, the following description will be continued. The output terminal voltage Vo of the sensor pad 110 becomes 5 V by charging.

After the charge of the sensor pad 110 is charged, the sensing periods T2, T4, T6 and T8 are followed. In this section, the current control switch SW of the current flow controller 213 connects the sensor pad 110 and the charging voltage supply terminal and is connected through one of the resistors R1, R2, R3, ..., Rn, . That is, the current control switch SW connects the sensor pad 110 with one of a plurality of nodes respectively connected to the charge voltage supply terminal through predetermined resistors R1, R2, R3, ..., Rn. Accordingly, even if the charging periods T1, T3, T5 and T7 are finished, the charging current Vpre_charge and the minute currents supplied by the resistors R1, R2, R3, ..., Rn are supplied to the sensor pad 110.

The driving unit 214 applies an alternating voltage (KB) to the sensor pad 110 in the sensing periods T2, T4, T6 and T8 so that the waveform of the output voltage Vo of the sensor pad 110 changes .

In particular, in the sensing periods T2, T4, T6, and T8 to which the fine current is supplied, when the alternating voltage KB is changed from high (5V) to low (0V), the output terminal voltage Vo of the sensor pad 110 is instantaneously. Descends. As described above, an increase or a decrease in the output voltage Vo of the sensor pad 110 according to the application of the alternating voltage (KB) is referred to as a kickback.

Meanwhile, the degree to which the output terminal voltage Vo of the sensor pad 110 is lowered may vary depending on the connected capacitance. For example, in the case of a touch detection method using a capacitance between the sensor pad 110 and a contact and a change in the capacitance, the degree of the drop depends on the capacitance value. On the other hand, in the case of a touch detection method through the mutual capacitance Cm between the driving line Tx and the sensing line Rx, the degree of the voltage drop varies depending on the magnitude of the mutual capacitance Cm.

The output terminal voltage Vo of the sensor pad 110 which has dropped in the sensing periods T2, T4, T6, and T8 rises to a normal state (i.e., 5V) over time. This is because the sensor pad 110 is in a state of being supplied with a minute current, not in a floating state. Since the fine current supplied by the charging voltage Vpre_charge and the resistors R1, R2, R3, ..., Rn continuously supplies the charge to the sensor pad 110, the output terminal voltage (Vo) is restored to the normal state again.

At this time, the time τ at which the output terminal voltage Vo of the sensor pad 110 which has been dropped returns to the normal state is determined by a characteristic inherent to the output terminal of the sensor pad 110 (for example, Capacitors, drive capacitors, etc.).

The output voltage Vo of the sensor pad 110 at the non-touch sensing periods T2 and T4 and the sensing periods T6 and T8 at the touch time, as shown in FIG. 7, A change in the output terminal voltage Vo of the sensor pad 110 in the first sensing periods T2 and T4 and a change in the output terminal voltage Vo of the sensor pad 110 in the second sensing periods T6 and T8 Vo) is different by? V.

That is, when the level change amount of the output terminal voltage Vo at the touch sensor pad 110 measured at the sensing periods T6 and T8 is the non-touch measured at the sensing periods T2 and T4, Is smaller than the level change amount of the output terminal voltage Vo at the sensor pad 110. [ At this time, the amount of change in the level of the output terminal voltage Vo of the sensor pad 110 may be varied depending on whether or not a capacitor (for example, a touch capacitor) is formed between the sensor pad 110 and the contact object .

Since the amount of change in the voltage level of the output terminal voltage Vo of the sensor pad 110 at the time of touching and non-touching is different from each other, it is possible to detect whether or not the touching is performed. Also, it is possible to detect whether or not the sensor pad 110 is touched by comparing the amount of change in the level of the output terminal voltage Vo of the sensor pad 110 with a reference value at non-touch.

In the present invention, the minute current supply periods T2, T4, T6, and T8 are used instead of the intervals (T2 and T4 in FIG. 5) in which floating is performed after the charging periods T1, T3, T5, and T7 for charging the sensor pad 110 ).

That is, in the present invention, a sensing period is not used as a sensing state, and a sensing current is supplied to the sensor pad 110 as a sensing period.

Specifically, the touch detection unit 210 according to the embodiment of the present invention charges the sensor pad 110 through the current flow controller 213 and then charges the charge voltage Vpre_charge and the resistors R1, R2, R3, ..., and Rn and supplies the fine currents to the sensing periods T2, T4, T6, and T8, By detecting the change in the voltage Vo, a touch is detected.

Therefore, it is possible to accurately detect whether or not the touch is generated without using a floating state vulnerable to disturbance.

Meanwhile, the sensing periods T2, T4, T6, and T8 must have similar characteristics to the periods in which the floating state is maintained in place of the periods in which the floating state is maintained in the method described with reference to FIGS. 4 and 5, The current supplied in the sensing period (T2, T4, T6, T8) must be of such a small magnitude as not to be susceptible to disturbance. In order to maintain this characteristic, the values of the predetermined resistors R1, R2, R3, ..., Rn must be appropriately selected.

The plurality of sensor pads 110 arranged in a plurality of rows and columns isolated from each other have different characteristics from each other due to a distance from the touch detecting portion 210 or other reasons. For example, each sensor pad 110 is connected to the touch detection unit 210 through a signal line 120 (see FIG. 3). Accordingly, the sensor pad 110 disposed far from the touch detection unit 210 And is connected to the touch detection unit 210 through the long signal line 120. That is, the sensor pad 110 disposed far away from the touch detection unit 210 is connected to the touch detection unit 210 through the signal line 120 having a larger resistance. Accordingly, the current flow controller 213 may include a plurality of nodes connected through the resistors R1, R2, R3, ..., Rn having different sizes from the charge voltage supply terminal, R2, R3, ..., Rn may be selected according to the characteristics of the resistor 110. For example, when touch detection is performed on the sensor pad 110 that is farthest from the touch detection unit 210, a plurality of signal lines 120 are connected to the signal pad 120, A node connected to a resistor having the smallest resistance value among the resistors R1, R2, R3, ..., Rn may be selected and connected to the sensor pad 110. [ That is, the current control switch SW of the current flow control unit 213 includes a plurality of resistors R1, R2, R3, ..., Rn, ..., Rn as far as the sensor pad 110, which is far from the touch detection unit 210, A resistance having a low resistance value may be selected and connected to the sensor pad 110. [

6 and 7, the touch sensing apparatus 100 according to an embodiment of the present invention may further include a sample and hold unit 215 connected to an output terminal of the sensor pad 110 .

The sample and hold unit 215 accumulates the output terminal voltage Vo of the sensor pad 110 a plurality of times and outputs the accumulated voltage for a predetermined time period, that is, the voltage of the output terminal TP2 of the sample and hold unit 215 This is a part for confirming whether or not touch detection is performed.

Specifically, the switch SW_SH of the sample-and-hold unit 215 can be turned on in a period in which a minute current is supplied to the sensor pad 110, that is, in each sensing period T2, T4, T6, and T8 , So that the output terminal voltage Vo of the sensor pad 110 can be accumulated in the capacitor C_SH. It is possible to detect whether the touch is detected through the voltage of the output terminal TP2 of the sample and hold unit 215 which varies depending on the amount of charge accumulated in the capacitor C_SH. That is, the voltage value change amount DELTA V_TP2 at the both ends of the capacitor C_SH of the sample and hold unit 215 for a predetermined time has different values at the time of touching and at the time of non-touch, .

Further, in another embodiment, the switch SW_SH of the sample-and-hold unit 215 may be turned on in a predetermined specific period (for example, a period including at least two sensing periods) By using the change amount of the output terminal voltage Vo of the sensor pad 110 accumulated in the capacitor C_SH, that is, the amount of change (e.g., rise width) of the output terminal TP2 voltage of the sample and hold unit 215, .

On the other hand, the capacitor C_SH can be reset at regular intervals.

Meanwhile, an amplifier A1 for amplifying a signal may be further included between the sensor pad 110 and the switch SW_SH of the sample and hold unit 215. An amplifier A2 and an analog-to-digital converter (ADC) may be connected to the output node TP2 of the sample and hold unit 215 and the amplifier A2 may be connected to the output node TP2 of the sample- The voltage value change amount? V_TP2 is amplified or differentially amplified. In the differential amplification, the reference value Ref may be a signal corresponding to the non-touch reference value or the charging signal. The analog-to-digital converter (ADC) converts the signal amplified by the amplifier A2 into a digital signal and outputs it. The amplifier A2 and the analog-to-digital converter (ADC) may correspond to the level shift detection unit 212 in Fig.

On the other hand, since the sample and hold unit 215 can serve as a low-pass filter as its own resistance or resistance existing in the circuit and the capacitor C_SH itself, high-frequency noise may accumulate the filtered voltage.

The sample and hold unit 215 according to the embodiment of the present invention may be included for performing touch detection by more clearly distinguishing the difference between when the touch is generated and when the touch is generated through the voltage accumulation, have. When the sample-and-hold unit 215 is omitted, whether or not the touch is generated is detected only through the output terminal voltage Vo of the sensor pad 110. That is, when the sample and hold unit 215 is omitted, the output terminal of the sensor pad 110 may be directly connected to the input terminal of the amplifier A2.

8 is a circuit diagram for explaining a configuration of a touch detection unit in a touch detection apparatus according to another embodiment of the present invention.

The touch detection unit 210 shown in FIG. 6 is a circuit for a self-capacitance type touch screen panel, whereas the touch detection unit 210 shown in FIG. 8 is a mutual capacitance type touch screen panel Fig.

6 illustrates a touch detection unit 210 of a touch detection device that performs touch detection for a sensor pad 110 formed of one electrode, that is, touch detection through electrostatic capacitance formed between the sensor pad 110 and a touch input tool, 8 shows a configuration of the touch detection unit 210 in the mutual capacitance type in which the sensor node 110 'composed of the driving line Tx and the sensing line Rx is the touch detection target unit FIG. Specifically, the mutual capacitive touch screen panel includes one or more sensor nodes 110 'arranged in a row or column direction. The sensor node 110 'comprises a drive line Tx to which a driving signal is applied and a sensing line Rx for providing a signal sensing point for touch detection. The sensor node 110' Unit area.

A driving signal for touch detection is applied to the driving line Tx. For example, an alternating voltage (KB) alternating at a predetermined frequency may be applied to the driving line Tx so that a mutual capacitance Cm is formed between the driving line Tx and the sensing line Rx do. The magnitude of the mutual capacitance Cm may vary according to the touch state of the sensor node 110 ', and accordingly, the voltage Vo output from the sensing line Rx may vary. For example, when a touch input tool such as a finger or a conductor touches the sensor node 110 ', the driving line Tx and the sensing line Rx The mutual capacitance Cm formed between the first and second electrodes can be changed. That is, the sensing line Rx may output a different voltage level value in response to the alternating voltage (KB) when the touch occurs and not when the touch occurs, thereby detecting whether or not the touch is generated.

The operation of the touch detection unit 210 shown in FIG. 8 is the same as the operation of the touch detection unit 210 shown in FIG. 6 except that the sensor pad 110 is replaced with a sensor node 110 'composed of a driving line Tx and a sensing line Rx Operation is the same. Hereinafter, the operation thereof will be briefly described.

The current flow controller 213 charges the charge on the sense line Rx, and then supplies the fine current.

The current control switch SW of the current flow controller 213 directly connects the charge voltage supply terminal and the sense line Rx in a period in which the charge is charged in the sense line Rx, The current control switch SW selects one of the plurality of resistors R1 ', R2', R3 ', ..., Rn' connected to the charge voltage supply end and detects the other end of the corresponding resistor Line Rx.

That is, the current control switch SW of the current flow controller 213 is connected to the node directly connected to the charging voltage supply terminal and one of the plurality of nodes connected through the predetermined resistors R1 ', R2', R3 ', ..., Rn' And connects it to the sensing line Rx.

In a period in which a fine current is supplied after the sensing line Rx is charged, the driving unit 214 applies an alternating voltage (KB) to the driving line Tx.

As described above, if the alternate voltage KB is supplied to the driving line Tx while the fine current is supplied to the sensing line Rx after charging, the voltage is detected at the sensing line Rx according to whether the touch is generated The voltage Vo varies. The touch detection unit 210 can detect whether a touch is generated through the amount of change in the voltage Vo of the sensing line Rx at the non-touch time and at the touch time.

That is, the touch detection unit 210 shown in FIG. 8 is different from the touch detection unit 210 shown in FIG. 6 in that the current flow control unit 213 charges the charge on the sense line Rx, And the driving unit 214 applies the alternating voltage (KB) to the driving line Tx, and the remaining operations are the same. Therefore, both the sensor node 110 'in FIG. 8 and the sensor pad 110 in FIG. 6 function as a unit area of touch detection and are understood to have the same meaning in this specification. The process of detecting the change of the output voltage Vo of the sensing line Rx in FIG. 8 should be understood to mean the same as detecting the change of the output voltage Vo of the sensor pad 110 in FIG.

In the touch detection apparatus according to the present invention, whether or not a touch is generated is detected by changing an output signal according to an alternate voltage supply in a state of supplying a minute current after charges are charged at a point of occurrence of a touch. The step of charging the electric charge is indispensable. However, by replacing the floating state for isolating the charged electric charge after the charging with the supply of the minute current, not only the instability of the floating state vulnerable to the disturbance can be solved, but also accurate touch detection becomes possible .

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.

Claims (13)

A current flow controller for charging a specific sensor node among a plurality of sensor nodes and supplying a minute current;
A driver for applying an alternating voltage to the sensor node in the minute current supply period; And
And a detector configured to detect whether a touch is performed based on an output terminal voltage of the sensor node according to the alternating voltage applied during the minute current supply period.
The method of claim 1,
Wherein the current flow control section includes a current control switch for directly connecting the sensor node and the charging voltage supply terminal or selectively connecting the sensor node and the charging voltage supply terminal through a selected one of a plurality of resistors.
3. The method of claim 2,
When the current control switch directly connects the sensor node and the charging voltage supply terminal, the sensor node is charged with electric charge,
Wherein the current control switch selects one of the plurality of resistances and connects the sensor node and the charging voltage supply terminal through the selected resistance, the fine current is supplied to the sensor node, .
The method of claim 3, wherein
Wherein the current control switch comprises:
Wherein when the fine current is supplied, the sensor node selects a resistor having a lower resistance value as the sensor node is disposed far away from the driving apparatus driving the plurality of sensor nodes.
The method of claim 1,
Wherein:
And a touch detection device performing touch detection by comparing the output terminal voltage change of the sensor node according to the alternating voltage to the minute current supply section with a reference value.
The method of claim 1,
Further comprising a sample and hold unit for sampling and accumulating an output terminal voltage of the sensor node,
Wherein the detection unit detects whether or not the voltage stored in the sample-and-hold unit is compared with a reference value.
The method according to claim 6,
The sample-and-
And stores the output terminal voltage of the sensor node after sampling only after the minute current supply period.
Charging a specific sensor node among the plurality of sensor nodes;
Supplying a fine current to the sensor node;
Applying an alternating voltage to the sensor node during the minute current supply period; And
And detecting a touch based on an output terminal voltage of the sensor node according to the alternating voltage applied during the minute current supply period.
The method of claim 8,
Wherein the charging step includes directly connecting the sensor node and the charging voltage supply terminal,
Wherein the fine current supply step includes connecting the sensor node and the charge voltage supply terminal through one of the plurality of resistors selected.
The method of claim 9,
Wherein the fine current supplying step includes:
Selecting a resistance having a lower resistance value as the sensor node is located farther away from the driving apparatus driving the plurality of sensor nodes.
The method of claim 8,
The detecting step,
And performing touch detection by comparing an output terminal voltage change of the sensor node according to the alternating voltage applied to the minute current supply interval with a reference value.
The method of claim 8,
The detecting step,
Sampling the output terminal voltage of the sensor node and storing the sampled voltage; And
And comparing the accumulated voltage with a reference value to detect whether or not the touch is detected.
13. The method of claim 12,
The accumulation step,
Sampling the output terminal voltage of the sensor node only after the microcurrent supply period.

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