KR20160095406A - Touch input device for diminishing low frequency noise - Google Patents

Abstract

The present invention relates to a touch input device for removing a low frequency noise, which provides a structure of removing an influence by a parasitic capacitor of an electrode pad provided in a capacitance-type touch sensor layer. The touch input device includes a touch electrode pad arranged to generate a touch input capacitance between user input tools, a first switch, a first operational amplifier, a second switch, and a second operational amplifier. A first one terminal of the first switch is connected with the touch electrode pad, and a first opposite terminal of the first switch is connected with a non-inverting input terminal of the first operational amplifier. A second one terminal of the second switch is connected with the touch electrode pad, and a second opposite terminal of the second switch is connected with a non-inverting input terminal of the second operational amplifier. A first potential (VH) is applied to an inverting input terminal of the first operational amplifier, and a second potential (VL) is applied to an inverting input terminal of the second operational amplifier (in this case, second potential < first potential). A first integration capacitor is connected between the non-inverting input terminal of the first operational amplifier and an output terminal of the first operational amplifier. A second integration capacitor is connected between the non-inverting input terminal of the second operational amplifier and an output terminal of the second operational amplifier.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch input device for eliminating low-frequency noise,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a capacitive touch input device, and more particularly, to a device for determining whether a touch input is performed by combining two touch input sensing parts operating in different time phases.

FIGS. 1A and 1B are examples of a touch input circuit for explaining the principle of a self-capacitance touch input. The touch input circuit may be a part of an electronic device.

An equivalent capacitance formed by the capacitance Cf 18, the parasitic capacitance Cp 20 and other capacitance Ce 23, the resistance Rref 12, The non-inverting input terminal of the operational amplifier 15, the switch 14, and the electrode pad 16 may be connected. The electrode pad 16 may be a transparent or opaque conductive material. The reference potential Vref may be provided to the inverting input terminal (-) of the conjunctive amplifier 15. In one embodiment, the reference potential Vref may be greater than the ground potential.

At this time, the capacitance (Cf) 18, which is an element constituting the 'equivalent capacitance', is set such that when a voltage is applied to the electrode pad 16 and a conductor such as a finger approaches the electrode pad 16 , Capacitance (Cf) 18, and the electric conductor. That is, the value of the capacitance (Cf) 18 changes according to whether or not the touch input is performed, and it is possible to know whether or not the touch input is performed by measuring the changed value.

On the other hand, the parasitic capacitance (Cp) 20 may be an unintentionally designed capacitance formed between the electrode pad 16 and other parts of the electronic device. Therefore, the value of the parasitic capacitance (Cp) 20 may be a value that is not previously known by the designer of the touch input circuit.

At this time, if the value of the parasitic capacitance Cp is sufficiently small or does not exist, the change amount of the capacitance Cf 18 can be easily measured.

Also, there is a problem that the noise generated or introduced from other parts of the electronic device is transmitted to the node n1 through the node n2 existing at one end of the parasitic capacitance Cp. Other capacitances (Ce) 23 formed in other parts of the electronic device may further be connected to the node n2.

The ON / OFF state of the switch 14 is controlled by the reference voltage Vref applied to the inverting input terminal (-) of the operational amplifier 15 and the voltage Vx of the node n1 applied to the non-inverting input terminal (+ As shown in FIG.

As shown in Fig. 1B, the voltage Vx of the node n1 may vary depending on the change of the on / off state of the switch 14. [ 'Off' shown in the horizontal axis of FIG. 1B means a time interval during which the switch 14 is kept in an off state, and 'On' may mean a time period during which the switch 14 is kept in an on state.

The rate of change of the voltage Vx when the switch 14 is in the on state can be determined by the above-mentioned 'equivalent capacitance' and the time constant τ determined by the resistor Rref 12. When the switch 14 is turned off, the voltage Vx falls back to the reference potential.

The size of the capacitance Cf 18 may vary depending on how close the finger 17 is located to the electrode pad 16, and as a result, the magnitude of the 'equivalent capacitance' may change. Therefore, the value of the time constant? Can be changed according to the change amount of the capacitance Cf. The change in the time constant tau affects the rate of change of the voltage Vx in the time period during which the switch 14 shown in Fig. 1B is kept in the ON state. Therefore, by using the values related to the voltage Vx graph, information on the magnitude of the time constant?, The magnitude of the capacitance Cf 18, and how much the finger 17 affects the electrode pad 16 Can be calculated inversely. Thus, it is possible to know whether or not the touch input has been performed.

For example, in the case where the finger 17 is not present near the electrode pad 16, there is no capacitance (Cf) 18. As a result, it can be assumed that the value of the 'equivalent capacitance' is Ce1. Now, when the finger 17 is present near the electrode pad 16, the capacitance Cf 18 is present, and if the value of the equivalent capacitance is Ce2, the relationship of Ce2 &gt; Can be satisfied. As a result, the time constant tau1 in the case where the finger 17 is not present near the electrode pad 16 is smaller than the time constant tau2 in the case where the finger 17 is present in the vicinity of the electrode pad 16. 1b, when the finger 17 is not present near the electrode pad 16, the voltage Vx rises more rapidly than when the finger 17 is present near the electrode pad 16 can do. With this phenomenon, it is possible to determine whether or not the finger 17 is present near the electrode pad 16, for example, by measuring the time taken for the potential Vx to rise from the value of 0 to Vref.

Fig. 1C and Fig. 1D are circuits corresponding to Figs. 1A and 1B, respectively, in which a circuit in which the resistor Rref 12 of Fig. 1A is replaced by a constant current source Ire_1 12_1, Of the time. The operation of the circuit according to FIG. 1C and FIG. 1D will be readily understood by one of ordinary skill in the art with reference to FIGS. 1A and 1B.

FIGS. 1E and 1F are examples of a touch input circuit provided to explain mutual capacitance type touch input. The touch input circuit may be a part of an electronic device.

Referring to FIG. 1E, a first electrode pad VCOM 11 and a second electrode pad VCOM 12 are disposed on a substrate 512 so as to be insulated from each other by an insulator 511. At this time, if a predetermined voltage is applied to the first electrode pad VCOM 11, the magnetic flux 510 generated from the first electrode pad VCOM 11 is directed to the second electrode pad VCOM 12. At this time, a mutual capacitance Cs is formed between the first electrode pad VCOM 11 and the second electrode pad VCOM 12 by the magnetic flux 510. At this time, if there is a touch input tool such as a finger in a space to which the magnetic flux 510 exiting from the insulator exits, the magnetic flux 510 exiting to the outside is input to the second electrode pad VCOM 12 Do not. Accordingly, the value of the mutual capacitance Cs changes. The mutual capacitance type touch input circuit determines whether touch input is performed by measuring the value of the mutual capacitance Cs. The electrode to which a predetermined voltage is applied, such as the first electrode pad VCOM 11 in FIG. 1E, may be referred to as a driving electrode pad, and the second electrode pad VCOM 12 may be referred to as a sensing electrode pad.

FIG. 1F shows an example of a touch input circuit of mutual capacitance type, and shows an example of a switched capacitor integration circuit. In Fig. 1F, the two switches turn on / off states according to the first clock Clk1 and the second clock Clk2, respectively, and do not share the time periods that become on-state. The current provided from the power supply Vs (t) is once charged in the capacitance Cs, and the charged charge is stored in the integral capacitor Cfb connected to the operational amplifier. In other words, the capacitance Cs accumulates and accumulates charges continuously on both ends of the integrating capacitor Cfb while continuously repeating charging and discharging. The larger the value of the capacitance Cs, the more charge per unit time can be charged to both ends of the integrating capacitor Cfb. Therefore, by checking the output voltage Vfb (t) of the operational amplifier, the magnitude of the capacitance Cs can be grasped. At this time, both ends of the capacitance Cs in FIG. 1F may be designed to be the first electrode pad VCOM 11 and the second electrode pad VCOM 12 in FIG. 1E, respectively.

A plurality of the electrode pads 16 may be arranged vertically and horizontally to determine whether the electrode pads are touched or not by the self-capacitance method shown in Figs. 1A to 1D. At this time, as the number of the electrode pads 16 increases, the power consumption of the circuit for touch input sensing increases, or the number of operational amplifiers increases to increase the circuit complexity. For example, in a case where the arrangement of the electrode pads 16 has a matrix structure of 20 * 12, 240 electrode pads are provided in total, and if one of the operational amplifiers is connected to each electrode pad, the complexity of the circuit becomes too large there is a problem.

The present invention provides a touch input device having a structure for eliminating the influence of parasitic capacitance caused by parasitic capacitance on an electrode pad of a capacitive touch sensor layer. In particular, it is desirable to provide a structure that can be applied when the parasitic capacitance is formed by the data control line (DL) and / or the gate control line (GL) of the screen display device adjacent to the touch input device.

According to an aspect of the present invention, there is provided a touch input sensing device including: a touch electrode pad arranged to generate a touch input capacitance with a user input tool; A first switch and a first operational amplifier; And a second switch and a second operational amplifier, wherein a first end of the first switch is connected to the touch electrode pad and a first end of the first switch is connected to an inverting input terminal of the first operational amplifier, The second end of the switch is connected to the touch electrode pad and the second end of the switch is connected to the inverting input terminal of the second operational amplifier and a first potential VH is applied to the noninverting input terminal of the first operational amplifier Inverting input terminal of the second operational amplifier is applied with a second potential VL and a first integral capacitor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the first operational amplifier And a second integrating capacitor is connected between the inverting input terminal of the second operational amplifier and the output terminal of the second operational amplifier.

The output signal of the touch input sensing device may be a value obtained by subtracting the value of the second output signal Vo2 of the second operational amplifier from the value of the first output signal Vo1 of the first operational amplifier.

At this time, the first switch and the second switch are alternately turned on and off while a current flows through the first integrating capacitor and the second integrating capacitor, and the first switch and the second integrating capacitor The on-state sections of the switches may not overlap each other.

At this time, whether or not touch input is performed through the touch electrode pad may be determined by using a difference in voltage between an output terminal of the first operational amplifier and an output terminal of the second operational amplifier.

At this time, the first potential may be larger than the second potential.

The touch electrode pad may be the common electrode of a screen output device including an image pixel, a control line for transmitting a signal for controlling the light output of the image pixel, and a common electrode of the image pixel.

An integrating device provided according to another aspect of the present invention is an integrating device connected to a touch electrode pad arranged to generate a touch input capacitance with a user input tool. The apparatus includes a first switch and a first operational amplifier; And a second switch and a second operational amplifier. The first switch has a first end connected to the touch electrode pad, the first end connected to the inverting input terminal of the first operational amplifier, and the second end of the second switch connected to the touch electrode pad. Inverting input terminal of the first operational amplifier is connected to the second inverting input terminal of the first operational amplifier, the second inverting input of the second operational amplifier is connected to the second inverting input terminal of the second operational amplifier, A first integrating capacitor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the first operational amplifier, and the second operational amplifier And a second integrating capacitor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the second operational amplifier.

According to the present invention, it is possible to provide a touch input device having a structure for eliminating the influence of parasitic capacitance parasitic on the electrode pad of the electrostatic touch sensor layer.

FIGS. 1A and 1B are examples of a touch input circuit for explaining the principle of a self-capacitance touch input.
Fig. 1C and Fig. 1D are circuits corresponding to Figs. 1A and 1B, respectively, in which a circuit in which the resistor Rref 12 of Fig. 1A is replaced by a constant current source Ire_1 12_1, Of the time.
FIGS. 1E and 1F are examples of a touch input circuit provided to explain mutual capacitance type touch input.
2A shows a self-capacitance touch input circuit according to an embodiment of the present invention.
Fig. 2B is an example of a circuit corresponding to Fig. 2A, in which the resistance (Rref) 12 of Fig. 2A is replaced by a constant current source (Iref) 12_1.
FIG. 3 is a schematic diagram of an integrated input / output device 1, which is formed integrally with a 'capacitive touch sensor layer' and a 'screen output device' by sharing one or more kinds of parts. The integrated input / output device 1 may include a touch IC (T-IC) 3 and a display output control chip (DDI) 2.
4 is a more detailed view of the configuration of the vicinity of the four VCOM electrodes on the upper left side of FIG.
Figs. 5A to 5C show the structures in the three image pixels N11, N31 and N33 shown in Fig. 4 in more detail, respectively.
FIG. 6A conceptually illustrates the problem described in FIGS. 5A through 5C, and FIG. 6B illustrates a modified embodiment from FIG. 6A.
7A to 7C show the structure of a circuit for eliminating the influence of parasitic capacitors according to three different embodiments of the present invention.
8 (a) shows a plan view of the integrated input / output device 4 provided according to an embodiment of the present invention. 8 (b) conceptually shows an exploded cross-sectional view of the integrated input / output device 4 shown in Fig. 8 (a).
Fig. 9 is a diagram showing the timing charts of the electrostatic drive signal (i.e., the drive signal for sensing the capacitive touch sensor) and the pen drive signal (i.e., the drive signal for sensing the stylus pen) according to an embodiment of the present invention. For example.
10 is a timing chart of the electrostatic drive signal, the pen drive signal, and the display unit drive signal according to an embodiment of the present invention.
11 illustrates a technique for recognizing a touch input gesture according to another embodiment of the present invention.
12 shows an example in which the waveform of the periodic voltage signal Vdp is provided in the form of a periodic AC waveform without a DC component
13 shows a circuit structure according to an embodiment of the present invention for eliminating the influence of parasitic capacitance Cp, yy in the circuit of Fig.
14A and 14B illustrate a structure in which signals of the same voltage are applied to a touch input device and a display device according to an embodiment of the present invention.
FIG. 15A shows a configuration of a circuit that performs a function of detecting touch input according to another embodiment of the present invention. FIG. 15B illustrates a capacitive component formed between the touch input tool 17 and the electrode pads VCOM and xx in FIG. 15A by using a capacitor Cp.
16A to 16E illustrate an example of a method of operating the low-frequency noise removal detection circuit shown in FIG. 15B.
17A shows an example of the waveforms of the voltages (Vx, xx) of the nodes (Nx, xx) obtained during the repetition of the circulation period of FIGS. 16B to 16E after the initialization step of FIG. 16A.
FIG. 17B shows an example of waveforms of the first voltage output Vo1 and the second voltage output Vo2 that can be obtained as a result of repeating the circulation period of FIG. 16B to FIG. 16E in a specific detection period.
Fig. 18 is a timing chart of the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 at the times t0, t1, t2, t3 and t4 described with reference to Figs. (Vx, xx) of the nodes (Nx, xx).
Figs. 19A to 19E, Figs. 20 and 21 show modified embodiments from Figs. 16A to 16E, 17 and 18, respectively.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. Also, the singular forms as used below include plural forms unless the phrases expressly have the opposite meaning.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a touch input sensing method for reducing an influence of a parasitic capacitance and an apparatus therefor

2A shows a self-capacitance touch input circuit according to an embodiment of the present invention. The node n1 is connected to the equivalent capacitance formed by the touch capacitance Cx and xx, the parasitic capacitance Cp and yy and the other capacitance Ce 23, the resistance Rref 12, The non-inverting input terminal (+) of the amplifier 15, the switch 14 and the electrode pads VCOM and xx (i.e., the VCOM and the xx electrodes) can be connected. The electrode pads VCOM, xx can be transparent or opaque conductive materials. The reference potential Vref may be provided to the inverting input terminal (-) of the conjunctive amplifier 15. In one embodiment, the reference potential Vref may be greater than the ground potential. At this time, the touch capacitance Cx, xx of the equivalent capacitance is generated when a dielectric such as a finger comes close to the electrode pads VCOM, xx and an electric field is formed therebetween. That is, the value of the touch capacitance (Cx, xx) changes depending on whether or not the touch input is performed, and it is possible to know whether the touch input is performed by measuring this value. On the other hand, the parasitic capacitance Cp, yy may be an unwanted capacitance formed between the electrode pads VCOM, xx and other circuits. At this time, if the value of the parasitic capacitance Cp, yy is sufficiently small or does not exist, the amount of change of the touch capacitance Cx, xx can be easily measured. Also, in some cases, the parasitic capacitance Cp, yy may change dynamically with time. Also, the node n2, which is one end of the parasitic capacitance Cp, yy, has a side effect of transmitting the noise introduced from the other part of the circuit to the node n1. The node n2 may further be connected to other capacitances Ce 23 formed in other parts of the circuit. The on / off state of the switch 14 is determined by the difference between the reference voltage Vref applied to the inverting input terminal of the operational amplifier 15 and the voltage Vx, xx of the node n1 applied to the non- Can be determined accordingly.

Fig. 2B is an example of a circuit corresponding to Fig. 2A, in which the resistance (Rref) 12 of Fig. 2A is replaced by a constant current source (Iref) 12_1.

In the circuits of Figs. 2A and 2B, an amplifier 24 is further disposed between the node n1 and the node n2. The amplifier 24 transmits the voltages Vx and xx of the node n1, that is, the electrode pads VCOM and xx to the node n2 as it is, so that the voltages Vx and xx and the voltages Vy and yy are forced Or substantially equal to each other or to greatly reduce the difference between the voltages Vx and xx and the voltages Vy and yy. As a result, the voltage between both ends of the parasitic capacitance Cp becomes 0 or becomes close to zero. As a result, no or little current flows from the node n1 to the node n2, and the influence of the parasitic capacitance Cp disappears. As a result, only the capacitances Cx and xx constitute the above-mentioned equivalent capacitance. Therefore, the circuit according to FIG. 2A or 2B can successfully measure only the change amount of the capacitance Cx, xx.

FIG. 3 is a schematic diagram of an integrated input / output device 1, which is formed integrally with a 'capacitive touch sensor layer' and a 'screen output device' by sharing one or more kinds of parts. The integrated input / output device 1 may include a touch IC (T-IC) 3 and a display output control chip (DDI) 2.

Here, the electrostatic touch sensor layer may mean a device in which transparent electrodes are disposed in a single layer or two layers.

The screen output device may be a liquid crystal display, and preferably a TFT-LCD panel. The TFT-LCD panel can be used as an LCD panel, a diffusion plate, a light guide plate, a reflection plate, a light source, a glass substrate, an LC layer, a black matrix, a color filter, a common electrode (VCOM), an alignment film, Lines (data control lines and / or gate control lines), which are well known in the art. The common electrode VCOM may be formed as a single wide substrate over the entire area of the TFT-LCD panel, or may be divided or divided into M * N matrices.

The screen output control chip 2 is provided with terminals DL connected to a plurality of data control lines of the screen output device, terminals CL connected to a plurality of gate control lines of the screen output device, There are provided terminals VCOM [M * N] connected to a plurality of VCOM electrodes arranged in an M * N matrix form among the components constituting the screen output device. In the embodiment of FIG. 3, M = 12 and N = 8.

The touch IC 3 is similarly provided with terminals VCOM [M * N] connected to the plurality of VCOM electrodes. The terminals VCOM [12 * 8] connected to the screen output control chip 2 and the terminals VCOM [M * N] connected to the touch IC 3 are the same in Fig.

In one embodiment of the present invention, the control right of the VCOM electrodes may be divided into the touch IC 3 and the screen output control chip 2 according to time.

That is, in the integrated input / output device 1 of FIG. 3, the 'capacitive touch sensor layer' and the 'screen output device' share a plurality of electrodes, at least VCOM, as common components. Here, each of the plurality of VCOM electrodes may correspond to the VCOM and xx electrodes (i.e., the electrode pads described above) shown in FIG. 2A.

4 is a more detailed view of the configuration of the vicinity of the four VCOM electrodes on the upper left side of FIG.

The plurality of data control lines DL1, DL2, DL3, ... extend in the vertical direction in the figure, and the plurality of gate control lines CL1, CL2, CL3, Extended. By controlling the potentials of the data control lines DL1, DL2, DL3, ... and the gate control lines CL1, CL2, CL3, ..., The image can be controlled. Here, the image pixels existing at the intersection are denoted by Nyy. For example, an image pixel at a node where the data control line DL1 and the gate control line GL1 intersect is denoted by N11.

Here, the image pixels may be represented by one pixel by grouping RGB. One image pixel may be provided with three data lines and one gate line for each of 'R', 'G', and 'B'. The above-described common electrode VCOM is arranged close to all the picture pixels. These techniques are already well known.

In FIG. 4, one VCOM electrode is illustrated as passing two data control lines and two gate control lines, but may be more or less.

Figs. 5A to 5C show the structures in the three image pixels N11, N31 and N33 shown in Fig. 4 in more detail, respectively.

Referring to FIG. 5A, an electric signal applied through the data control line DL1 affects the transistor T11, at which time the gate control line GL1 adjusts the gate voltage of the transistor T11. The screen output device shown in Figs. 3 and 4 includes electrodes VCOM and xx. At this time, between the data control line DL1, the gate control line GL1, the transistor Tyy (for example, T11), and the VCOM and xx electrodes (for example, VCOM and 11 electrodes), various capacitors 61 to 66 Component) is present. Some of these capacitors 61-66 are intentionally formed, and others may be unintentionally generated parasitic capacitors. In FIG. 5A, the capacitors 61 to 66 are modeled as a total of six capacitors. Hereinafter, an explanation will be given on the assumption that six models are modeled.

The VCOM, 11 electrode is an electrode used as a sensor for a touch input of the self-capacitance type, as described above with reference to FIG. 2A. That is, VCOM, 11 is a component commonly used by the touch IC 3 and the screen output control chip 2 of FIG. 3. For this purpose, in the embodiment of the present invention, the VCOM 11 is connected to the touch IC 3, The control chip 2 can be used in a time-division manner. The same holds true for VCOM other than VCOM, 11, and xx.

It is not easy to obtain equivalent capacitors by the capacitors 61 to 66. Nevertheless, the amount of charge flowing through the VCOM, the capacitors 64, 65 and 66 directly connected to the 11 electrode, and the capacitance (? Cx, 11) formed between the VCOM, 11 electrode and the touch input tool 17 It can be understood that the touch input sensing characteristic is determined. In the case of the touch IC 3, the capacitors 61 to 66 and the like can be collectively regarded as the parasitic capacitor C11.

The parasitic capacitor C11 may be regarded as a capacitor having the nodes n11 to n12 as the first poles and the nodes n21 to n24 as the second poles.

5A, the parasitic capacitor C11 is connected to three points of the VCOM, the eleventh electrode, the data control line DL1, and the gate control line GL1, but the dual gate control line GL1 , It can be approximated that both terminals of the parasitic capacitor C11 are VCOM, the 11 electrode and the data control line DL1.

Here, the capacitance (? Cx, 11) varies depending on the presence or proximity of the touch input tool (17) and is indicated using the symbol?. The transfer of electric charges flowing between the VCOM electrode 11 and the capacitors 64, 65 and 66 is also variable according to the variable electrical characteristics of the data control line DL1 and the gate control line GL1. The parasitic capacitors ΔCp, 11) are also shown using the symbol Δ.

2A, since the influence of the parasitic capacitors can be minimized by making the voltages on both sides of the parasitic capacitors equal to each other or to be almost equal to each other, it is possible to prevent the parasitic capacitor C11 from being short- The voltage of the VCOM electrode 11 can be applied to the data control line DL1 at 1: 1 using the amplifier 24 so that the voltages of the data lines DL1 are substantially equal to each other.

As described above, it is said that the capacitive touch sensor layer and some parts of the screen output device are shared with each other. However, the data control lines DL1, DL2, DL3, ... are also shared as described above. In one embodiment of the present invention, the time period for outputting the screen and the time period for sensing the electrostatic touch input are exclusively mutually divided. The data control lines DL1, DL2, DL3, ... ), The electric signal corresponding to the image output data is applied. However, during the period when the capacitive touch input is sensed, the electrostatic touch input by the parasitic capacitor (? Cp, 11,? Cp, 12,? Cp, 13, The output of the amplifier 24 can be applied to the data control lines DL1, DL2, DL3, ... in order to minimize the error.

Referring to FIGS. 5A and 5B, the VCOM electrode connected to the transistor T11 in FIG. 5A is the VCOM electrode and the VCOM electrode connected to the transistor T31 in FIG. 5B is the VCOM electrode. At this time, the voltage of VCOM and the voltage of the electrode 21 are set to be equal to each other by using the amplifier 24 so as to make the voltages of the VCOM at both ends of the parasitic capacitor C31 and the data control line DL1 almost equal to each other 1: 1 to the data control line DL1. However, it can not be constructed simply. This is because the picture pixel N11 and the picture pixel N31 share the data control line DL1 and the VCOM electrode connected to the picture pixel N11 and the picture pixel N31 is VCOM, And the voltages of the VCOM electrode 11 and the VCOM electrode 21 may be different from each other. Therefore, it is impossible to simultaneously apply voltages of two terminals having different voltages to one data control line. A method for solving this is described in Figs. 7A to 7C.

Referring again to FIG. 5C, to see the picture pixel N33, it can be seen that the VCOM electrode is composed of VCOM and 22 electrodes. At this time, because the data control line DL3 is connected to the image pixel N33, at least the VCOM is applied to the data control line DL1 in FIGS. 5A and 5B, the amplifier 24 ).

5A to 5C illustrate a configuration in which the output terminal of the amplifier 24 is connected to the data control line DL. In another example, however, the output terminal of the amplifier 24 may be connected to the gate control line GL. I can understand.

5A to 5C, the switch SW1 may be connected to the VCOM electrode and the xx electrode. This switch SW1 is connected to Vref2 during a period in which the display unit driving signal 53 shown in Fig. 10 is activated and connected to the node n1 during a period in which the electrostatic driving signal 52 is activated. Here, Vref2 may be GND and may be a reference potential to which all the VCOM and xx electrodes are commonly connected while the image control signal is applied to the data control line DL and the gate control line GL. The node n1 may be a node corresponding to the node n1 shown in Fig. 2A. That is, the node n1 may be a node connected to the touch sensing sensor using the electrodes VCOM and xx as the touch sensing sensor.

And a switch SW2 may be connected between the data control line DL and the amplifier 24. [ The switch SW2 is turned off during a period in which the display unit driving signal 53 is activated and turned on during a period in which the electrostatic driving signal 52 is activated.

SW1 SW2 During a period in which the display unit driving signal 53 is activated Connect to Vref2 OFF The period during which the electrostatic drive signal 52 is activated Connect to n1 ON

FIG. 6A conceptually illustrates the problem described in FIGS. 5A through 5C.

Referring to FIG. 6A, voltages of two or more VCOM and xx electrodes (VCOM, 11 electrodes, VCOM, 21 electrodes) having different voltages may be applied to one data control line DL1. At this time, naturally, it is not possible to simultaneously apply the first voltage VCOM, the first voltage VCOM, and the second voltage of the electrode 21 to the data control line DL1. In any case, in order to arbitrarily apply a certain potential to one data control line DL1, only one output of the amplifier 24 must be connected to one data control line DL1.

This also applies to the other data control line DL3 shown in Fig. 6A.

6A is a structure that can be applied when the data control line has a much greater influence than the gate control line in forming the parasitic capacitance DELTA Cp, yy. In contrast, in the case where the gate control line has much more influence on the parasitic capacitance? Cp, yy than the data control line, the structure shown in FIG. 6B can be applied.

7A to 7C show the structure of a circuit for eliminating the influence of parasitic capacitors according to three different embodiments of the present invention.

7A shows a circuit structure for applying a voltage corresponding to a voltage of VCOM to a data control line, according to an embodiment of the present invention.

In FIG. 7A, the data control line DL1 is connected to the data control line DL1 among a plurality of all of the VCOMs, the x1 electrodes (VCOM, 11 electrodes, VCOM, 21 electrodes, VCOM, 31 electrodes, One of them is selected arbitrarily or by a predetermined rule, and the voltage of the selected VCOM, x1 is applied to the data control line DL1. 7a, the input of the amplifier 24 may be directly connected to the selected particular VCOM electrode.

As shown in Fig. 7A, the potentials according to time of the VCOM, the 11 electrode, the VCOM, and the 21 electrode can not always be the same, and therefore, they are different from each other.

7B shows a circuit structure for applying a voltage corresponding to the voltage of VCOM to the data control line according to another embodiment of the present invention.

7B, potentials appearing in all of a plurality of VCOM, x1 electrodes (VCOM, 11 electrodes, VCOM, 21 electrodes, ...) which can be connected to the data control line DL1 are averaged in the data control line DL1 To the data control line DL1. For this purpose, an average value calculation circuit that produces an average of different voltages can be used. The average value calculation circuit can be implemented using the principle of a differential amplifier that receives a plurality of inputs of one phase as a differential input terminal.

FIG. 7B shows an example of a waveform obtained by averaging the voltages of VCOM, 11 electrodes, VCOM, and 21 electrodes over time, although not strictly shown.

7C shows a circuit structure for applying a voltage corresponding to the voltage of VCOM to a data control line according to another embodiment of the present invention.

In Fig. 7C, a configuration is adopted in which a voltage provided by a predetermined method in a reference wave generator is outputted to the data control line DL1 and applied to the data control line DL1. FIG. 7C shows an example of the output of the reference waveform generator. At this time, the output of the reference waveform generator may be a periodic signal. And the period may be, for example, the same as the period in which the switch 14 is opened and closed in Fig.

In one embodiment, the data control line (DL), the gate control line (GL), and VCOM, xx shown in Figs. 2 to 6 are arranged such that, during a period in which the display unit driving signal 53 shown in Fig. It can be used for the function of the control chip 2 and can be used for the function of the touch IC (T-IC) 3 in the section in which the electrostatic drive signal 52 shown in Fig. 10 is activated. To this end, in one embodiment, if there are artificially created capacitors among the capacitors 64, 65, 66 of FIG. 5A, the path between the capacitors and VCOM, xx includes a switch not shown in FIGS. 5A, 5B, May be provided. The switch SW2 may also be provided in the path between the data control line DL1 and the output terminal of the amplifier 24. [

8 (a) shows a plan view of the integrated input / output device 4 provided according to an embodiment of the present invention. 8 (b) conceptually shows an exploded cross-sectional view of the integrated input / output device 4 shown in Fig. 8 (a). 8 (a) and 8 (b) will be described together.

The integrated input / output device 4 may be a device in which the electrostatic touch sensor layer 100, the screen output device 200, and the touch pen sensor layer 300 are combined.

The screen output device 200 may include or be connected with a screen output control chip (D-IC) 121 for processing a display signal together with a material for display. At this time, the screen output control chip 121 may be a device including a display driver IC (DDI). In one embodiment, the DDI can function to adjust the transistors attached to the subpixels displaying RGB of the three primary colors among the pixels provided on the display screen, and can be classified into a gate IC and a source IC.

In one embodiment, the DDI may be coupled to a T-CON (Timing Controller) and used together to control the display device.

The electrostatic-type touch sensor layer 100 may include a touch IC (T-IC) 111 for processing a signal for sensing electrostatic touch input together with a material for detecting the electrostatic touch input, The pen sensor layer 300 may include or be connected to a pen sensor chip 131 for processing a signal for detection of a pen touch input together with a material for detecting a pen touch input.

In this case, although the order in which the three devices are stacked is not necessarily determined in a specific order, in one embodiment, the touch pen sensor layer 300 is disposed on the lowest layer, the screen output device 200 is disposed on the middle layer, Type touch sensor layer 100 may be disposed on the uppermost layer.

3 to 7, the screen output device 200 and the capacitive touch sensor layer 100 may be integrally formed to share some components (e.g., a VCOM electrode) .

In another embodiment, any two or more of the capacitive touch sensor layer 100, the screen output device 200, and the touch pen sensor layer 300 may share components with each other. When parts are shared, they can be called 'integrated' or 'hybrid'.

The screen output device 200 may be provided using an apparatus such as an LCD, a PDP, an AMOLED, and an OLED. When the electrostatic touch sensor layer 100 or the touch pen sensor layer 300 covers the screen output device 200, the screen output device 200 is covered so that the output of the screen output device 200 can be visually confirmed The touch panel may be configured to be substantially transparent to the human eye.

The capacitive touch sensor layer 100 and the touch pen sensor layer 300 may be provided to cover the light emitting area of the screen output device 200. [ When a person takes an input gesture aimed at a specific coordinate on the screen output device 200, the touch panel must be able to accurately detect the coordinates at which this input gesture is made.

In one embodiment, the display resolution of the screen output device 200 is R1, the user input resolution of the touch pen sensor layer 300 is R2, and the user input resolution of the capacitive touch sensor layer 100 is R3 , For example, a relation of R1> R2> R3 may be established. If R2 and R3 are close to R1, a better user input experience can be provided.

9A is a timing chart showing the timing of the electrostatic drive signal (that is, the drive signal for sensing of the capacitive touch sensor) and the pen drive signal (that is, the drive signal for sensing the stylus pen) according to the embodiment of the present invention . In one embodiment of the present invention, the electrostatic drive signal 52 may occur in a constant period T, intermittently on the time axis (i.e., interrupted midway). At this time, the electrostatic drive signal 52 may continue for a predetermined second sustain period T2. The patterns of the electrostatic drive signals 52 in the respective second sustain periods T21 and T22 may be the same or different from each other. At this time, the pen drive signal 51 may be generated so that the electrostatic drive signal 52 does not overlap with the generation timing. 9 illustrates that the pen drive signal 51 is generated in the first sustain periods T1, T11, and T12 that are all remaining times except for the second sustain period T2 in which the electrostatic drive signal 52 is generated.

The above-described electrostatic drive signal may be an internal signal indicating that the capacitive touch sensor is sensed, and the pen drive signal may be an internal signal, which means that sensing of the stylus pen is permitted.

Figure 9 (b) shows a timing diagram modified from Figure 9 (a). 9 (b), the pen driving signal 51 may or may not occur between the second sustain periods 52, which is a period in which the electrostatic drive signal 52 is generated.

Figure 9 (c) shows another timing diagram modified from Figure 9 (a). A temporal gap may exist between the first sustain period T3 of the pen drive signal 51 and the second sustain period T2 of the electrostatic drive signal 52. [

Although three examples are shown in Fig. 9, any form of modification is within the scope of the present invention as long as the generation periods of the pen drive signal 51 and the electrostatic drive signal 52 do not overlap each other on the time axis.

10 (a) and 10 (b) are timing diagrams of an electrostatic drive signal, a pen drive signal, and a display unit drive signal according to an embodiment of the present invention. The electrostatic drive signal and the pen drive signal in Figs. 10 (a) and 10 (b) are the same as those shown in Fig. 9 (c). Here, the display unit driving signal may be, for example, a driving signal of the DDI described above, that is, a DDI driving signal.

The timing diagram of FIG. 10A can be applied when the screen output device 200 and the capacitive touch sensor layer 100 are provided separately on different layers.

In particular, the timing diagram of FIG. 10 (a) can be usefully applied when the screen output device 200 and the capacitive touch sensor layer 100 are provided in unified form. In the case where the screen output device 200 and the electrostatic touch sensor layer 100 are integrated, there may exist parts shared by the two devices. In this case, the control of the input / You can have time-sharing at different times promised in advance. As a result, the fourth sustain period T4, which is the generation period of the display unit drive signal 53 as shown in FIG. 10A, may not overlap the second sustain period T2, which is the generation period of the electrostatic drive signal 52 have.

Fig. 10 (b) is a modification of Fig. 10 (a). 10A, the third sustain period T3, which is the generation period of the pen drive signal 51, is included in the fourth sustain period T4, which is the generation period of the display unit drive signal 53. However, 10B illustrates that only a part of the fifth sustain period T5, which is a generation period of the pen drive signal 51 and the third sustain period T3, overlaps with each other.

Although not shown, the generation period of the pen drive signal 51 and the generation period of the display unit drive signal 53 may not overlap each other.

The timing diagrams illustrated in Fig. 10 show the first condition that the sustain period of the electrostatic drive signal 52 does not overlap the sustain period of the pen drive signal 51 and the first condition that the sustain period of the electrostatic drive signal 52 is the display section drive signal 53) and the second condition that it does not overlap with the sustain period of the first and second frames 53, 53, respectively.

11 illustrates a technique for recognizing a touch input gesture according to another embodiment of the present invention.

The touch input sensing circuit 10 shown in FIG. 11 may include an operational amplifier 215 and an integrating capacitor Cf connected between the inverting input terminal and the output terminal of the operational amplifier 215. At this time, the voltage signal Vdp may be input to the non-inverting input terminal of the operational amplifier 210. [ For convenience, the input terminal 211 of the touch input sensing circuit 10 can be defined. The input terminal 211 may be the same terminal as the inverting input terminal of the operational amplifier 215.

The voltage signal Vdp may be a signal having periodicity. Further, it may be an attention signal having a DC component of 0, that is, an AC period signal. Or the voltage signal Vdp may be a signal that is not a periodic signal but contains a component of the frequency fc.

11, the magnitude of the current flowing through the nodes Vx and xx is equal to the sum of the capacitances Cx and xx formed between the electrode pads VCOM and xx and the finger 17 and the parasitic capacitances Cp and yy It can be influenced by the size of the capacitance. This equivalent capacitance can be named Cxe.

The input terminal 211 of the touch input sensing circuit 10 may be connected to VCOM, xx shown in FIG.

12 shows an example in which the waveform of the periodic voltage signal Vdp is provided in the form of a periodic AC waveform without a DC component

12 (a) shows an AC sine wave, (b) shows an AC triangle wave, and (c) shows an AC square wave. In each case, the output voltage Vo of the operational amplifier 215 of FIG. 11 outputs a waveform of the same or similar form as the AC sine wave, the AC triangle, and the AC square wave. The output voltage Vo may have a frequency component different from the center frequency fc, and the other frequency components may be (1) a frequency component inherent in the voltage signal Vdp, or (2) a voltage May be a frequency component generated by distortion from the signal (Vdp), or (3) a frequency component provided by noise introduced from the outside.

At this time, the amplitude of the output voltage Vo may be proportional to the magnitude of the above-described equivalent capacitance Cxe and tend to be inversely proportional to the magnitude of the integral capacitor Cf. Therefore, since the size of the integral capacitor Cf is known in advance, the magnitude of the equivalent capacitance Cxe can be calculated by measuring the amplitude of the output voltage Vo. If the influence of the parasitic capacitance Cp and yy can be excluded if the value of the parasitic capacitance Cp and yy can be determined in advance and the influence thereof can be excluded, (Cx, xx) formed between the electrodes 17 can be obtained.

The amplitude of the output voltage Vo can be directly measured in the case where the waveform of the periodic voltage signal Vdp is provided in the form of a periodic AC waveform having no DC component, Can be mixed to measure the output voltage. In this case, only the frequency component equal to the sinusoidal wave among the components of the output voltage Vo can be extracted. (Sin (2? Fc)) equal to the center frequency fc of the voltage signal Vdp can be used as the sinusoidal wave. As a result, the noise components of the frequency components other than the center frequency fc can be eliminated.

13 shows a circuit structure according to an embodiment of the present invention for eliminating the influence of parasitic capacitance Cp, yy in the circuit of Fig.

The voltage of the inverting input terminal (-) of the operational amplifier 215 is regarded as being equal to the voltage of the non-inverting input terminal (-). Therefore, the voltage of one node n1 of the parasitic capacitance Cp, yy connected to the inverting input terminal (-) and the same node n1 is the same as the voltage signal Vdp.

At this time, when the voltage signal Vdp is applied to the other node n2 of the parasitic capacitance Cp, yy, the potential difference across the parasitic capacitance Cp, yy becomes zero, so that the parasitic capacitance Cp, So that it can operate as if the parasitic capacitance Cp, yy does not exist.

At this time, the other node n2 of the parasitic capacitance Cp, yy may be connected to a specific node of the electronic device. At least at the time of sensing the touch input, the other node n2 The switch SW3 can be provided so that the voltage signal Vdp can be provided.

FIG. 14 shows a configuration of applying a signal of the same voltage to a touch input device and a display device according to an embodiment of the present invention.

The VCOM control unit 220 may be connected to a plurality of different electrode pads VCOM, 11 / VCOM, 12 / VCOM, 21 / VCOM,

The detailed configuration of the VCOM control unit 220 is shown in FIG. 14B. A circuit that performs the same or similar function as the touch input sensing circuit 10 of Fig. 11 or the same or similar function can be connected to the interface terminal 221 of the VCOM control unit 220 by the switch SW5. Or the interface terminal 221 of the VCOM control unit 220 may be connected to the reference potential Vref2 by the switch SW5. Here, the reference potential may be a reference potential to which all of the VCOM and xx electrodes are commonly connected while the image control signal is applied to the data control line DL and the gate control line GL.

At this time, each of the touch input sensing circuits 10 can detect whether or not touch input is performed in each of the electrode pads VCOM, 11 / VCOM, 12 / VCOM, 21 / VCOM 22.

The operation timing of the switch SW5 may be set differently for each VCOM control unit 220. [ For example, while the interface terminal 221 of the VCOM control unit 220 connected to the VCOM 11 electrode is connected to the reference potential Vref2, the interface terminal 221 of the VCOM control unit 220 connected to the VCOM 12 electrode Can be connected to the input sensing circuit (10). In this case, touch input detection at the VCOM 11 electrode is not performed, but touch input detection at the VCOM 12 electrode can be performed.

At this time, the parasitic capacitance Cp, yy between the respective electrode pads and the gate control lines GL1, GL2, ... adjacent to the electrode pads and the data control lines DL1, DL2, . Therefore, the voltage signal Vdp can be applied to the gate control lines GL1, GL2, ... and the data control lines DL1, DL2, ... in accordance with the principle described with reference to FIG. The voltage signal Vdp may be the same signal as the signal provided to the non-inverting input terminal (+) of the operational amplifier 215 of the touch input sensing circuit 10. [

Each of the image pixels N11, N12, ..., N21, N22, ... is connected to the gate control lines GL1, GL2, ... and data control lines DL1, DL2, An &quot; image control signal &quot; Accordingly, the 'voltage signal Vdp' may be applied in the first time period and the 'picture control signal' may be applied in the second time period not overlapping the first time period. The switch SW4 may be used for this purpose.

For example, in the period T4 and T5 in which the display unit driving signal 53 shown in Fig. 10 is activated, the switch SW4 turns on the gate control lines GL1, GL2, ... and the data control lines DL1, DL2,. And may be connected to the voltage signal Vdp output terminal in the period T2 during which the electrostatic drive signal 52 is activated.

Hereinafter, an electronic device according to an embodiment of the present invention will be described with reference to FIGS. 11 to 14B.

This electronic device is provided with a touch input device for applying a touch driving voltage Vdp to a touch electrode pad VCOM, xx arranged to generate a touch input capacitance Cx, xx with the user input tool 17, And the touch generating unit applies the touch driving voltage to the touch electrode pad. The 'touch driving signal generating unit' may be an apparatus in which the operational amplifier 215, the integrated capacitor Cf, and the voltage signal Vdp generating unit shown in FIG. 13 are connected to each other. However, the present invention is not limited thereto, It is possible to cope with touch input circuits of various other configurations.

At this time, the electronic device is connected to the touch driving voltage (Vdp) at the first pole (n2, GL, DL) of the second capacitor (Cp, yy) which is formed in the electronic device and distinguishable from the touch input capacitance And the corresponding voltage Vdp is applied. At this time, the second electrode n1 of the second capacitor Cp, yy may be directly connected to the touch electrode pad VCOM, xx.

The M * N electrode pads shown in the embodiment of the present invention may have respective independent wires drawn from each other. That is, M * N electrode pads and M * N wirings drawn therefrom may exist.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings.

The touch input sensing device according to an embodiment of the present invention includes a touch input sensing electrode VCOM, xx; A touch sensing unit 10 connected to a point n1 of the touch input sensing electrode and adapted to measure a change in a touch capacitance Cx, xx formed by the touch input sensing electrode according to a touch input; The second node n2 having a capacitance Cp, yy between the first node n1 and the second node n2 included in the touch input sensing device; And a potential controller (Vdp or) for providing the second node with a potential value that follows the potential (Vx, xx) of the one point to reduce the potential difference between the first point (n1) and the second node (n2) 24).

Here, the touch input sensing electrode includes an image pixel ex11, a control line ex1 (DL1 or GL1) for transmitting a signal for controlling the light output of the image pixel, and a common electrode VCOM , 11) of the screen output device.

At this time, the second node is connected to the control line (ex: DL1 or DL2) of the screen output device including the picture pixels, a control line for transmitting a signal for controlling the light output of the picture pixel, GL1. &Lt; / RTI &gt;

At this time, the screen output device may be a TFT-LCD.

Here, the touch input sensing electrode may include a plurality of image pixels, a plurality of control lines for transmitting signals for controlling light output of the plurality of image pixels, and a plurality of common lines provided for the plurality of image pixels Is a first common electrode (ex: VCOM, 11) among the plurality of common electrodes of a screen output device including electrodes (ex: VCOM, 11, VCOM, 21, VCOM, 31, The potential value may be a potential value of any one common electrode (ex: VCOM, 11 or VCOM, 21) selected by a predetermined method among the plurality of common electrodes.

Alternatively, the touch input sensing electrode may include a plurality of image pixels, a plurality of control lines for transmitting a signal for controlling light output of the plurality of image pixels, and a plurality of common Is a first common electrode (ex: VCOM, 11) among the plurality of common electrodes of a screen output device including electrodes (ex: VCOM, 11, VCOM, 21, VCOM, 31, The potential value may be an average value of potential values of the plurality of common electrodes ex (VCOM, 11, VCOM, 21, VCOM, 31, ...).

Here, the touch input sensing electrode is the common electrode of a screen output device including an image pixel, a control line for transmitting a signal for controlling the light output of the image pixel, and a common electrode of the image pixel, The period of the potential value may be the same as the period of the common electrode.

The touch sensing unit includes an operational amplifier 215, a signal Vdp having a first frequency fc component is applied to a first input terminal (+) of the operational amplifier and the second node, The second input terminal of the operational amplifier may be connected to the touch input sensing electrode.

According to another embodiment of the present invention, a user equipment including a touch input sensing device and a screen output device may be provided. Here, the touch input sensing device may include: 1) a touch input sensing electrode; 2) a touch sensing unit connected to one point of the touch input sensing electrode and adapted to measure a change in a touch capacitance formed by the touch input sensing electrode according to a touch input; 3) a second node included in the touch input sensing device, wherein a capacitance is formed between the first node and the one point; And 4) a potential control unit for providing the second node with a potential value following the potential of the one point so as to reduce the potential difference between the one point and the second node. And the screen output device comprises: 5) an image pixel; 6) a control line for transmitting a signal for controlling the light output of the image pixel; And 7) a common electrode of the image pixel. And the common electrode is the touch input sensing electrode.

<First Embodiment of Present Invention>

FIG. 15A shows a configuration of a circuit for performing a function of detecting touch input according to the first embodiment of the present invention.

The electrode pads VCOM, xx of FIG. 15A may be any of the plurality of electrode pads VCOM [M, N] shown in FIG. When the touch input tool 17 such as a finger touches or comes close to the electrode pads VCOM and xx, variable capacitances Cx and xx are formed between the electrode pads VCOM and xx and the touch input tool 17 .

The electrode pads VCOM and xx may be connected to the inverting input terminal of the first operational amplifier 315 and the inverting input terminal of the second operational amplifier 316 through the first switch SW1 and the second switch SW2, have.

The third switch SW3 and the first integrating capacitor Cf1 may be connected in parallel between the inverting input terminal of the first operational amplifier 315 and the output terminal Vo1. A voltage having a magnitude of VH may be applied to the non-inverting input terminal of the first operational amplifier 315.

The fourth switch SW4 and the second integrating capacitor Cf2 may be connected in parallel between the inverting input terminal of the second operational amplifier 316 and the output terminal Vo2. And a voltage having a magnitude of VL may be applied to the non-inverting input terminal of the second operational amplifier 316. [ At this time, it is assumed that the relation VH> VL holds in the first embodiment.

FIG. 15B illustrates a capacitive component formed between the touch input tool 17 and the electrode pads VCOM and xx by a capacitor Cfr in FIG. 15A. The value of the capacitor Cfr may vary depending on the presence or absence of a touch input.

In the first embodiment of the present invention, the output signals of the circuits shown in Figs. 15A and 15B are the first output voltage Vo1 of the first operational amplifier 315 and the second output voltage Vo2 of the second operational amplifier 316 ). &Lt; / RTI &gt; Hereinafter, the circuit shown in Fig. 15A or 15B may be referred to as a &quot; low frequency noise removal detection circuit &quot;.

16A to 16E illustrate an example of a method of operating the low-frequency noise removal detection circuit shown in FIG. 15B.

16A shows the state of the low-frequency noise removal detection circuit at time t0. At time t0, the second switch SW2 is kept open, and the first switch SW1, the third switch SW3, and the fourth switch SW4 are kept closed. In this way, the low frequency noise cancellation detection circuit can be initialized such that the voltage across the first integrating capacitor Cf1 and the second integrating capacitor Cf2 becomes zero. And the voltages (Vx, xx) of the nodes (Nx, xx) to VH. The value of the first output voltage Vo1 which is the voltage of the output node of the first operational amplifier 315 becomes VH and the value of the second output voltage Vo2 which is the voltage of the output node of the second operational amplifier 316 Becomes VL.

16B shows the state of the low-frequency noise removal detection circuit at time t1. At time t1, the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 are all left open. At this time, the voltages (Vx, xx) of the nodes (Nx, xx) can be held at VH. The first output voltage Vo1 and the second output voltage Vo2 may be maintained at VH and VL, respectively.

16C shows the state of the low frequency noise removal detection circuit at time t2. At time t2, the first switch SW1, the third switch SW3, and the fourth switch SW4 are both opened, and the second switch SW2 is kept closed. At this time, the voltage (Vx, xx) of the node (Nx, xx) changes from VH to VL. In this process, a current flows through the second integrating capacitor (Cf2) The voltage Vo2 is reduced by? V2. At this time,? V2 is proportional to (VH-VL) and proportional to the capacitance (Cx, xx = Cfr) and inversely proportional to the capacitance of the second integrating capacitor (Cf2). However,? V2 is a value greater than zero.

16D shows the state of the low-frequency noise removal detection circuit at time t3. At time t3, the first switch (SW1) and the second switch (SW2). The third switch SW3, and the fourth switch SW4 are all left open.

16E shows the state of the low-frequency noise removal detection circuit at time t4. At time t4, the first switch SW1 is kept closed and the second switch SW2 is turned off. The third switch SW3, and the fourth switch SW4 are all left open. At this time, the voltages Vx and xx of the nodes Nx and xx change from VL to VH. In this process, a current flows through the first integrating capacitor Cf1 and the first output of the first operational amplifier 315 The voltage Vo1 is increased by DELTA V1. At this time,? V1 is proportional to (VH-VL) and proportional to the capacitance (Cx, xx = Cfr) and may be inversely proportional to the capacitance of the first integrating capacitor (Cf1). However,? V1 is a value greater than zero.

Then, the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 all return to the opened state as shown in FIG. 16B. 16B, the first output voltage Vo1 and the second output voltage Vo2 are changed to VH +? V1 and VL-? V2, respectively, compared to VH and VL.

In this specification, a series of processes from FIG. 16B, FIG. 16C, FIG. 16D and FIG. 16E can be referred to as a 'cycle cycle'. In one embodiment of the present invention, after the low-frequency noise removal sensing circuit is initialized in the manner as shown in Fig. 16A, the circulation period is repeated a predetermined number of times N. Fig. In a state after the cycle repeats N times, the output signal of the low-frequency noise canceling detection circuit (i.e., Vo1-Vo2) can be obtained. In the first embodiment, the acquisition of the output signal may be accomplished using an AD converter that receives the difference value of the output signals of the operational amplifiers 315, 316 as an input. After obtaining the output signal of the low frequency noise removal detection circuit, the low frequency noise removal detection circuit can be initialized in the same manner as in FIG. 16A. In this specification, the time from when the low-frequency noise removal detection circuit is initialized to when the output signal of the low-frequency noise removal detection circuit is obtained can be referred to as a 'detection period'. Therefore, the detection period is larger than the circulation period.

As described above, every time the cycle is repeated. The magnitude of the first output voltage Vo1 increases by? V1, and the magnitude of the second output voltage Vo2 decreases by? V2. It should be noted, however, that at this time, the values of? V1 and? V2 are variable values at every cycle. As described above, the values of? V1 and? V2 are determined by the capacitance (Cx, xx = Cfr). The value of the capacitance Cx, xx = Cfr may vary with time depending on the presence or absence of touch input Value.

For a total of N cycles after initializing the low-frequency noise canceling detection circuit, if each cycle is represented by an index k, k has a value of 1 to N. At this time, for each circulation period, the above-mentioned? V1 and? V2 can be denoted by? V1, k and? V2, k (where k = 1, 2, 3,. Therefore, if the cycle period is repeated N times after initializing the low-frequency noise removal detection circuit, the magnitude of the first output voltage Vo1 is VH +

The magnitude of the second output voltage Vo2 becomes VL -

. At this time, the output signal of the low frequency noise removing circuit is VH - VL +

+

. Depending on the generation state of the touch input,? V1, k =? V1 and? V2, k =? V2 may be established for all the k values within a specific sensing period.

17A shows an example of the waveforms of the voltages (Vx, xx) of the nodes (Nx, xx) obtained during the repetition of the circulation period of FIGS. 16B to 16E after the initialization step of FIG. 16A.

FIG. 17B shows an example of waveforms of the first voltage output Vo1 and the second voltage output Vo2 that can be obtained as a result of repeating the circulation period of FIG. 16B to FIG. 16E in a specific detection period. FIG. 17B shows an example in which the value of Cfr has a constant value. In the examples of FIGS. 17A and 17B, the above-described cycle period is repeated 11 times (= N) in total, and the initialization of the low-frequency noise canceling circuit is performed at t0 and t48.

In the first embodiment, the value collected to determine whether a touch input is made is a difference value between the first output voltage Vo1 and the second output voltage Vo2. In Fig. 17, the acquisition of the output signal of the low-frequency noise removal sensing circuit may be performed within a period of, for example, t44 to t48. As the value of N increases, the difference between the first output voltage Vo1 and the second output voltage Vo2 becomes larger.

Fig. 18 is a timing chart of the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 at the times t0, t1, t2, t3 and t4 described with reference to Figs. (Vx, xx) of the nodes (Nx, xx).

The difference value between the output voltages of the first operational amplifier 315 and the second operational amplifier 316 may be input to the input terminal of the AD converter. The touch input device according to the first embodiment of the present invention may include the above-described AD converter.

In the first embodiment of the present invention described with reference to Figs. 15 to 18, the circuit for judging whether or not a touch input is performed is largely divided into two parts. The first part comprises a first switch SW1, a first operational amplifier 315 and a first integral capacitor Cf1 and the second part comprises a second switch SW2, a second operational amplifier 316 ), And a second integral capacitor (Cf2).

The first output value of the first part is the voltage of the output terminal Vo1 of the first operational amplifier 315 and the second output value of the second part is the voltage of the output terminal Vo2 of the second operational amplifier 316 to be.

A change in the first output value occurs in a first time phase and a change in the second output value occurs in a second time phase. Here, the first time phase and the second time phase can respectively represent the times {t4, t8, t12, ...} and the times {t2, t6, t10, ...} shown in FIG. 17 and FIG. have.

&Lt; Second Embodiment of the Present Invention >

19A to 19E, 20, and 21 are views for explaining a second embodiment of the present invention. The second embodiment is an embodiment modified from the first embodiment described above.

Referring to Fig. 21, the on-off sequence of the switch SW1 and the switch SW2 in the first and second embodiments are exchanged with each other. 20, at time t2 when the first output voltage Vo1 of the first operational amplifier 315 begins to rise, the second output voltage Vo2 of the second operational amplifier 316 falls Is faster than the starting time (t4).

Claims (10)

A touch electrode pad arranged to generate a touch input capacitance with a user input tool;
A first switch and a first operational amplifier; And
A second switch and a second operational amplifier;
/ RTI &gt;
Wherein the first switch has a first end connected to the touch electrode pad and the first end connected to an inverting input terminal of the first operational amplifier,
The second end of the second switch is connected to the touch electrode pad and the second end of the second switch is connected to the inverting input terminal of the second operational amplifier,
A first potential is applied to the non-inverting input terminal of the first operational amplifier,
A second potential is applied to the non-inverting input terminal of the second operational amplifier,
A first integrating capacitor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the first operational amplifier,
And a second integrating capacitor is connected between the inverting input terminal of the second operational amplifier and the output terminal of the second operational amplifier.
Touch input sensing device. The touch sensing apparatus according to claim 1, wherein the output signal of the touch input sensing device is a value obtained by subtracting the value of the second output signal Vo2 of the second operational amplifier from the value of the first output signal Vo1 of the first operational amplifier , A touch input sensing device. The method according to claim 1,
Wherein the first switch and the second switch alternately switch between the on state and the off state and the on state sections of the first switch and the second switch do not overlap each other,
Touch input sensing device. 2. The touch sensing device of claim 1, wherein whether or not touch input is performed through the touch electrode pad is determined by using a difference in voltage between an output terminal of the first operational amplifier and an output terminal of the second operational amplifier, Input sensing device. 2. The touch input sensing device of claim 1, wherein the first potential is greater than the second potential. The method according to claim 1,
The touch electrode pad includes:
A common electrode of the screen output device including a picture pixel, a control line for transmitting a signal for controlling the light output of the picture pixel, and a common electrode of the picture pixel,
Touch input sensing device. An integrator coupled to a touch electrode pad arranged to generate a touch input capacitance with a user input tool,
A first switch and a first operational amplifier; And
A second switch and a second operational amplifier;
/ RTI &gt;
Wherein the first switch has a first end connected to the touch electrode pad and the first end connected to an inverting input terminal of the first operational amplifier,
The second end of the second switch is connected to the touch electrode pad and the second end of the second switch is connected to the inverting input terminal of the second operational amplifier,
A first potential is applied to the non-inverting input terminal of the first operational amplifier,
Inverting input terminal of the second operational amplifier is applied with a second potential different from the first potential,
A first integrating capacitor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the first operational amplifier,
And a second integrating capacitor is connected between the inverting input terminal of the second operational amplifier and the output terminal of the second operational amplifier.
Integrator. The integrating device according to claim 7, wherein the output signal of the integrating device is a value obtained by subtracting the value of the second output signal of the second operational amplifier from the value of the first output signal of the first operational amplifier. 8. The method of claim 7,
Wherein the first switch and the second switch are alternately turned on and off, and the ON-state sections of the first switch and the second switch do not overlap with each other. 8. The method of claim 7,
The touch electrode pad includes:
Wherein said common electrode is a common electrode of a screen output device including a picture pixel, a control line for conveying a signal for controlling the light output of said picture pixel, and a common electrode of said picture pixel.
Integrator.

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