TWM477575U - Self-capacitance sensing device for use in touch panel - Google Patents

Description

Self-capacitance sensing device for touch panel

This creation is a device for detecting a sensing signal, and more particularly relates to a device for a touch panel that converts touch information into a self-capacitance variation.

As a kind of capacitive touch panel, the self-capacitive touch panel is based on a self-capacitance sensing device. The capacitive sensing device converts the touch information of the touch panel into a self-capacitance change signal, and determines a touch position coordinate according to the self-capacitance change signal. The self-capacitance sensing device can be used not only to manufacture a separate touch panel, but also can be used in a related device, for example, a self-capacitance sensing device is combined with a display device to form a touch display screen. The self-capacitance sensing device is more and more widely used in smart phones and tablets because it requires only a single layer layout and wiring, has simple production technology, high yield and low cost. The electrode arrangement structure of the prior art single-layer self-capacitance sensing device is as shown in FIG. 12, using triangular or triangular-like electrodes 91, and the electrodes 91 are arranged in pairs to form complementary electrode pairs 92, and the electrode pairs 92 are repeatedly stacked. A panel that covers the entire touch panel or displays the screen. As is apparent from the electrode arrangement shown in Fig. 12, there is no cross-tracking between the electrodes 91, which makes the production process relatively simple. The prior art self-capacitance sensing device further includes a self-capacitance detecting unit that electrically connects the electrodes 91.

Figures 13 and 14 show the basic principle of self-capacitance detection. The electrode 91 is usually covered with a cover plate 93 made of a transparent insulating dielectric material. The self-capacitance of the self-capacitance sensing device, that is, the capacitance of the electrode 91 to the ground, is Cp as shown in FIG. When the human body 94 touches the cover plate 93, The human body approximates a ground, which is equivalent to a capacitance Cf connected to the ground on the electrode 91, thereby increasing the self-capacitance of the electrode 91 to the ground, as shown in FIGS. 13 and 14. By detecting the change in self-capacitance, it can be determined whether touch is occurring.

As shown in Fig. 12, the electrode 91 whose long base is located on the left side is numbered by 911L, 912L, ..., 91(M-1)L, 91ML, 91(M+1)L, ..., long base The electrode 91 on the right side is numbered by 911R, 912R, ..., 91(M-1)R, 91MR, 91(M+1)R, ..., and M represents a natural number. The two electrodes 91 of the same numeral number constitute an electrode pair, for example, the electrodes 91 numbered 91ML and 91MR constitute an electrode pair. When the touch occurs, the self-capacitance detecting unit transmits the amount of change in the self-capacitance of each of the electrodes 91. The touch point 99 causes self-capacitance changes of the six electrodes 91, and their numbers are 91 (M-1) L, 91 ML, 91 (M+1) L, 91 (M-1) R, 91 MR, and 91 (M, respectively. +1) R. Accordingly, the amounts of self-capacitance change are Dp1, Dp2, Dp3, Dp4, Dp5, and Dp6, respectively. Firstly, find the channel with the largest amount of change in the longitudinal direction as the channel where the touch occurs, that is, the channel whose displacement is Dp2 and the number is 91ML corresponding to the electrode 91, and the position of the center of gravity is determined by the amount of change of the upper and lower channels. The coordinate of the longitudinal axis of the handle; the ratio of the variation of the channel with the largest change and the variation of the opposite triangular electrode, the coordinates in the direction of the horizontal axis are obtained. The prior art self-capacitance sensing device also has the following defects and deficiencies: 1. The production technology is complicated; the electrode 91 of the prior art self-capacitance sensing device cannot generally make a true triangle in actual production, and Triangular trapezoidal replacement; in order to obtain better accuracy in the X-axis direction, a narrow trapezoidal side is usually required. For example, the number shown on the right side of the electrode 91 of the 911L is shown in Fig. 12. The smaller the width, the better, usually required to be 0.3 mm. Even smaller, this has certain requirements for technical capabilities, and becomes one of the factors that affect the reduction of production costs; 2. There are many production procedures; the minimum detection unit of the traditional structure is a pair of triangles, and in order to improve the linearity of the line, it will also Each triangle is split into two or more small triangles in parallel, such an electrode junction For laser technology, it needs to be cut many times, which becomes another factor that affects the production cost reduction. 3. For a touch panel module using a soft substrate, for example, a substrate made of a film material, if The electrode 91 of the prior art self-capacitance sensing device is used on the substrate. Since the tip end of the triangular electrode 91 is very thin, if the substrate is bent during production, transportation and testing, the electrode region may be used to manufacture the electrode. The transparent conductive material, such as Indium Tin Oxide (ITO), breaks, causing damage to the self-capacitance sensing device or even the touch panel; the fragile structure of the triangular electrode 91 is also a factor affecting the production cost reduction; The electrode material is required to be high; for some new materials for manufacturing the electrode 91, such as a metal mesh material, in order to ensure good bonding between the wires constituting the metal mesh, the minimum width of the electrode 91 is higher than that of the existing indium tin oxide. The (ITO) material is large and should be above 1 mm. This minimum width is difficult to accept for the prior art triangular electrode 91 for manufacturing a self-capacitance sensing device; Electro-Static Discharge (ESD) is inferior; for the existing mainstream transparent conductive material, indium tin oxide (ITO), its impedance is large. If an electrostatic discharge (ESD) event occurs, the width of indium tin oxide (ITO) is higher. Small areas, such as widths below 0.1 mm, are more prone to electrostatic discharge (ESD), resulting in short circuits between indium tin oxide (ITO) electrodes.

The technical problem to be solved by the present invention is to avoid the deficiencies of the prior art and to propose a self-capacitance change detecting method for a touch panel, and a self-capacitance sensing device using the same, and adopting a new self by improving the electrode structure. The capacitance detection method reduces the production cost of the self-capacitance sensing device and improves its overall efficiency.

The technical problem solved by the present invention can be achieved by adopting the following technical means: designing and manufacturing a self-capacitance sensing device for a touch panel, comprising at least one electrode, and a self-capacitance change detecting unit electrically connecting each electrode. The electrode has a rectangular shape and includes a first end and a second end for electrically connecting the self-capacitance change detecting unit along the extending direction of the electrode. The self-capacitance change detecting unit includes at least one variable acquisition module. The variable acquisition module includes a constant current source electrically coupled to the first node, a clamp circuit and a charge transceiver detection circuit, and a second node that is grounded. In the process of detecting an electrode, the first node of the variable acquisition module is electrically connected to the first end of the electrode, and the second node is electrically connected to the second end of the electrode, after the first self-capacitance change is collected. The first node of the variable acquisition module is electrically connected to the second end of the electrode, and the second node is electrically connected to the first end of the electrode to collect the second self-capacitance change amount. The clamping circuit limits a potential of one end of the electrically connected electrode to a constant potential, and the constant current source supplies a constant current to the electrically connected electrode; the charge transceiving detection circuit changes to a self-capacitance of the electrically connected electrode thereof The electrode outputs a charge and detects the amount of charge output, and quantizes the amount of charge output as a change in self-capacitance.

The clamp circuit defines a constant potential of one end of the electrically connected electrode as V1, and the constant current supplied from the constant current source to the electrically connected electrode is I, then V1/I=R should be satisfied, and R is a clamp The resistance of the electrode is electrically connected to the circuit and the constant current source.

Specifically, the clamp circuit includes an operational amplifier, and the constant potential defined by the clamp circuit is controlled by an input voltage of a forward input terminal of the operational amplifier. The charge transceiving detection circuit includes the operational amplifier used as a clamp circuit, electrically connected to a charge transceiving capacitor between an inverting input end and an output end of the operational amplifier, and an AC/DC electrically connected to an output end of the operational amplifier Convert submodules. The current output terminal of the constant current source and the inverting input terminal of the operational amplifier are electrically connected to the first node.

In order to reset the circuit state after each detection, a reset switch is further electrically connected between both ends of the charge transceiver capacitor.

A specific structure of an electrode is that at least one vertex of the electrode is cut to form a bevel of a straight segment, so that the electrode is processed into a rectangular electrode with a beveled edge.

Another specific structure of the electrode is that at least one of the apex angles of the electrode is cut away to form a circular arc edge, so that the electrode is processed into a rectangular electrode with a circular arc side.

Still another electrode has a specific structure in which at least one side of the electrode is machined with at least two grooves, and convex teeth are formed between the two adjacent grooves, so that the electrodes are processed into rectangular electrodes with serrated edges.

In a specific application, the electrode is made of indium tin oxide, a metal mesh or a carbon nanomaterial.

Regarding the arrangement of the electrodes, the self-capacitance sensing device further includes a substrate made of a resin synthetic film material or glass, and the electrodes are attached to the substrate.

When the self-capacitance sensing device is combined with the display device, the self-capacitance sensing device is mounted in the liquid crystal display screen. The liquid crystal display screen includes a first liquid crystal substrate and a second liquid crystal substrate, and a liquid crystal material, a pixel electrode, a color filter layer, and a black matrix sandwiched between the first liquid crystal substrate and the second liquid crystal substrate. The electrode is attached to an upper layer or a lower layer of the first liquid crystal substrate or an upper layer or a lower layer of the second liquid crystal substrate.

An electrode scanning detection method, the self-capacitance change detecting unit includes a set of variable collecting modules; the set of variable collecting modules are controlled to electrically connect the electrodes in sequence according to a set timing, that is, electrically connect the electrodes in time sharing The self-capacitance change detection of each electrode is completed.

In another electrode scanning detection mode, the number of the variable collection modules is less than the number of electrodes; each variable acquisition module is controlled to electrically connect all the electrodes one by one according to the set timing. The partial electrodes, that is, the electrodes are electrically connected in a time-divisionally divided region to complete the self-capacitance change detection of each electrode.

It is also possible to use a one-to-one electrode scanning detection method, and the variable acquisition module electrically connects the electrodes one-to-one.

When the self-capacitance sensing device is combined with the display device, the self-capacitance sensing device is mounted in the liquid crystal display screen. The liquid crystal display screen is controlled by a display driver circuit chip. The self-capacitance change detecting unit is integrated in the display driving circuit chip.

In order to coordinate the liquid crystal driving and the self-capacitance detection, the self-capacitance sensing device further includes a coordinated detecting module when the self-capacitance sensing device is combined with the display device. The self-capacitance sensing device is mounted in a liquid crystal display screen. The liquid crystal display screen is controlled by a display driving circuit. The coordinated detection module electrically connects the self-capacitance change detecting unit and the display driving circuit to complete the respective functions of the self-capacitance change detecting unit and the display driving circuit in a period of time and/or a sub-region without interfering with each other.

Compared with the prior art, the technical effect of the "self-capacitance sensing device for the touch panel" of the present invention is as follows: 1. The production technology is simple; the shape of the electrode of the creation is rectangular, and the longitudinal width of the electrode is relatively wide, which reduces the technology. The precision requirement can reduce the production cost; 2. The production efficiency is high; the shape of the electrode is rectangular, the minimum detection unit can be completed by cutting one knife, and the production efficiency is high; 3. The reliability is good and the fracture is not easy; Rectangular structure, the width value is relatively large, even if the substrate to which the electrode is attached is made of a soft material, the electrode is not easily broken when the substrate is bent; 4. The material requirements are low; the electrode of the present invention adopts a rectangular structure, and the minimum width value thereof is large. The electrode can be made of a new metal mesh material; 5. The antistatic discharge (ESD) effect is good; the existing mainstream electrode manufacturing material is indium tin oxide (ITO), The antistatic discharge (ESD) capability decreases with decreasing width. In this creation, the electrode has a relatively large width value and a strong antistatic discharge (ESD) capability.

10‧‧‧ electrodes

101‧‧‧Rectangular electrode

102‧‧‧Rectangular electrode

103‧‧‧Rectangular electrode

111‧‧‧Bevel

112‧‧‧ arc edge

113‧‧‧ Groove

114‧‧‧ convex teeth

115‧‧‧Wire

2‧‧‧Self-capacitance conversion detection unit

21‧‧‧Variable Acquisition Module

211‧‧‧Charge Transceiver Detection Circuit

2111‧‧‧ AC and DC converter submodule

212‧‧‧Constant current source

213‧‧‧Clamp circuit

3‧‧‧LCD screen

31‧‧‧First liquid crystal substrate

32‧‧‧Second liquid crystal substrate

33‧‧‧Liquid crystal materials

34‧‧‧pixel electrode

35‧‧‧Color filter layer

36‧‧‧Black matrix

91‧‧‧Electrode

911L‧‧‧electrode

912L‧‧‧electrode

91(M-1)L‧‧‧electrode

91ML‧‧‧electrode

91(M+1)L‧‧‧electrode

911R‧‧‧electrode

912R‧‧‧electrode

91(M-1)R‧‧‧electrode

91MR‧‧‧electrode

91(M+1)R‧‧‧electrode

92‧‧‧electrode pair

93‧‧‧ Cover

94‧‧‧ Human body

99‧‧‧ touch points

{0}~{k}‧‧‧

[1]~[n]‧‧‧埠

A‧‧‧first node

B‧‧‧second node

c‧‧‧Controlled

d‧‧‧Controlled

Cc‧‧‧Charge Transceiver

Ct‧‧‧ capacitor

DTU‧‧‧First self-capacitance change

DTV‧‧‧Second self-capacitance change

OP‧‧‧Operational Amplifier

R1~Rk‧‧‧Resistors

S1~Sn‧‧‧electrode

SnL‧‧‧ first end

SnR‧‧‧ second end

SW‧‧‧Reset switch

Vf‧‧‧ input voltage

Fig. 1 is a schematic view showing the arrangement of electrodes of the self-capacitance sensing device of the present invention.

Figure 2 is a schematic diagram of the electrical principle of the self-capacitance sensing device of the present invention.

FIG. 3 is a schematic diagram showing the electrical principle of the first self-capacitance change detection when the self-capacitance sensing device is touched.

FIG. 4 is a schematic diagram showing the electrical principle of the second self-capacitance change detection when the self-capacitance sensing device is touched.

Fig. 5 is a schematic diagram showing the electrical principle of an embodiment of the present self-capacitance sensing device.

Fig. 6 is a schematic view showing the structure of a rectangular electrode 101 having a hypotenuse.

Fig. 7 is a schematic view showing the structure of a rectangular electrode 102 having a circular arc side.

Fig. 8 is a schematic view showing the structure of a rectangular electrode 103 having a sawtooth edge.

Fig. 9 is a schematic view showing the structure of an electrode 10 made of a metal mesh.

Figure 10 is a schematic diagram showing an electrical principle of detecting each electrode 10 when a module component is acquired using a set of variables.

Figure 11 is a schematic cross-sectional view of a liquid crystal display screen.

Figure 12 is a schematic diagram showing the electrode arrangement structure of the prior art single-layer self-capacitance sensing device.

Figure 13 is a schematic diagram of the self-capacitance of the prior art self-capacitance sensing device when a touch occurs.

Figure 14 is a schematic diagram showing the equivalent electrical principle of the prior art self-capacitance sensing device when a touch occurs.

The embodiments are further described in detail below with reference to the embodiments shown in the drawings.

In order to eliminate the defects of the prior art triangular electrode, such as complicated production technology, many production procedures, easy breakage, high electrode material requirements and poor antistatic discharge (ESD) effect, the present invention uses a rectangular electrode. Compared with the triangular electrode, the rectangular electrode is obviously simplified in production technology and reduces the production process. Since the rectangular electrode has a large longitudinal width, the electrode is attached to the soft substrate, and the substrate is not easily broken even if the substrate is bent; and the larger longitudinal width of the rectangular electrode satisfies the minimum width requirement of the metal mesh material. The electrode is made of a metal mesh material; also because the rectangular electrode has a large longitudinal width, the antistatic discharge (ESD) performance of the electrode is also improved. As shown in FIG. 1, the self-capacitance sensing device proposed by the present invention includes a rectangular electrode 10, and the electrode 10 extends in the abscissa direction of the Cartesian coordinate system, and the electrodes 10 are parallel to each other along the ordinate direction of the Cartesian coordinate system. Within the entire touch area. Of course, the electrode 10 extends in the ordinate direction of the Cartesian coordinate system, and the electrodes 10 are arranged parallel to each other along the abscissa direction of the Cartesian coordinate system, which is an equivalent feasible technical means. As shown in Fig. 1, for the convenience of the following description, each electrode 10 is denoted by S1, ..., Sn, where n is a variable whose value is a natural number, and thus the electrode 10 numbered Sn can be represented. Suitable for any of the electrodes 10 of all of the electrodes 10. Each electrode 10 has two ends along the extending direction, that is, the X-axis direction of the Cartesian coordinate system. The electrodes 10 each include a first end L and a second end R, and the electrode 10 of the number S1 has a first end S1L and a second end. S1R, and so on, the electrode 10 numbered Sn includes a first end SnL and a second end SnR.

As shown in FIG. 2, the self-capacitance sensing device of the present invention further includes a self-capacitance change detecting unit 2 that electrically connects the electrodes 10, and the self-capacitance change detecting unit 2 detects the self-capacitance change of each electrode. The self-capacitance conversion detecting unit 2 specifically detects and acquires the self-capacitance change amount of the electrode 10 electrically connected to the variable collecting module 21 through the variable collecting module 21 . For any of the electrodes 10 numbered Sn, the first end SnL of the electrode 10 is connected to the charge transceiving detection circuit 211, The current source 212 and the clamp circuit 213 are fixed. The second end SnR of the electrode 10 is connected to ground. Therefore, the charge transceiver detection circuit 211, the constant current source 212, and the clamp circuit 213 are all electrically connected to the first node a of the variable acquisition module 21, and the second node b of the variable acquisition module 21 is grounded. The constant current source 212 flows into or out of a fixed amount of current. The clamp circuit 213 clamps the first node a, that is, the first terminal SnL end of the electrode 10 to a fixed voltage, and the charge transceiver detection circuit 211 can flow in or out of the charge, and can detect the amount of charge flowing in or out.

The voltage clamped by the clamp circuit 213 is V1, the resistance between the two ends of the electrode 10 is R, and the current of the constant current source 212 is I, and the relationship between them is: V1/R=I. Thus, in the case where no touch occurs, the current I provided by the constant current source 212 is such that the voltage of the resistance connection current source of the electrode 10 and the first terminal SnL of the clamp circuit is maintained at V1 without the charge transceiving detection circuit 211. The electric charge flows into or out, that is, the electric charge detected by the charge transmission/reception detecting circuit 211 when the touch is not generated is zero.

The electrode 10 can be equivalently connected in series with k resistors R1, R2, R3, ..., Rj, ..., Rk, and the resistance values are equal, and the upper nodes of each resistor are {0}, {1}, { 2}...{k-1}, the lower plate node of the last resistor is {k}, and the nodes {0} and {k} are the first end SnL and the second end SnR of the electrode 10, respectively. .

When the node {0} is connected to one end of the clamp circuit 213, that is, the first node a electrically connects the first end SnL of the electrode 10, and the second node b electrically connects the second end SnR of the electrode 10, the voltage of the node 0 is V1, node {k} is grounded, then the voltage on node {j} is:

When the node {k} is connected to one end of the clamp circuit 213, that is, the first node a is electrically connected to the second end SnR of the electrode 10, and the second node b is electrically connected to the first end SnL of the electrode 10, the voltage of the node {k} For V1, node {0} is grounded and the voltage on node {j} is:

When the touch of the node {j} occurs, as shown in Fig. 3, this event can be equivalent to a capacitance Ct connected between the touch point {j} and the ground.

As shown in FIG. 3, when the first end SnL of the electrode 10 is terminated to the clamp circuit 213, that is, the first node a electrically connects the first end SnL of the electrode 10, and the second node b electrically connects the second end SnR of the electrode 10. When, by the formula (1), the voltage on Ct is Then the charge Q1 stored on Ct is

Since the constant current source 212 can only supply the current flowing through the resistor string, this charge Q1 is supplied from the charge transceiving detection circuit 211 and can be quantized into the first self-capacitance variation.

After the above detection is completed, the first end SnL of the electrode 10 is changed to ground. The second end SnR of the electrode 10 is connected to the clamp circuit 212, that is, the first node a electrically connects the second end SnR of the electrode 10, and the second The node b electrically connects the first end SnL of the electrode 10 as shown in FIG. From equation (2), the voltage on Ct is: Then the charge Q2 stored on Ct is

Since the constant current source 212 can only supply current flowing through the resistor string, this charge is supplied by the charge transceiving detection circuit 211 and can be quantized into a second self-capacitance variation.

Therefore, the variable acquisition module 21 acquires two self-capacitance change amounts of the first self-capacitance change amount and the second self-capacitance change amount for the occurrence of the touch electrode 10 .

In this regard, the present invention proposes a self-capacitance change detecting method for a touch panel, which is based on a self-capacitance sensing device, and the self-capacitance sensing device includes at least one electrode. The electrode includes a first end and a second end along a first direction. Specifically, in the embodiment shown in Fig. 1, the first direction is the abscissa X-axis direction of the Cartesian coordinate system in the embodiment. The method performs the following steps for each electrode, A. electrically connecting a constant current source, a clamp circuit, and a charge transceiving detection circuit at a first end of the electrode, grounding the second end of the electrode; the constant current source to the electrode And outputting a current of a constant current value; the clamp circuit limits a potential of one end of the electrically connected electrode to a constant potential; the charge transceiving detection circuit is capable of outputting a charge or receiving a charge, and detecting a charge output amount or a receiving amount, and quantizing the electric charge The output is the self-capacitance change; B. The charge transceiver detection circuit detects whether there is a charge output; if there is a charge output, the quantized charge output or the charge reception amount is the first self-capacitance change amount, and then step C is performed; The case of the step is the case where the electrode is touched; if there is no charge output, directly performing step E; C. electrically connecting the constant current source, the clamp circuit and the charge transceiving detection circuit at the second end of the electrode, the electrode The first end is grounded; D. the charge transceiving detection circuit quantizes the charge output amount as the second self-capacitance change amount; E. the self-capacitance change for the electrode Detection end.

The method performs the above steps once for each electrode to complete the self-capacitance change detection for the electrode. It can be seen that the method directly detects the change in the self-capacitance of the electrode if the charge output or the received charge is not detected in step B. The first node and the second node are interchanged with the first end and the second end of the electrode only when the charge output or the received charge is detected. The operation of the electrical connection continues and the test continues. Of course, regardless of whether the charge transceiver detection circuit detects the charge output or the received charge, the first node and the second node are electrically connected to the first end and the second end of the electrode in a relatively fixed period of time, And the operation process of continuing detection should also be an alternative technical means of the above-mentioned technology of the present creation, and should be within the protection scope of the present creation.

The constant current source outputted from the constant current source of the step A as described above is I, and the clamp circuit makes the potential defined by the potential of one end of the electrically connected electrode to be V1, and then V1/I=R should be satisfied. R is the resistance of the electrode to which the clamp circuit and the constant current source are electrically connected.

Based on the above method, the present invention also provides a self-capacitance sensing device for a touch panel, comprising at least one electrode 10, and a self-capacitance change detecting unit 2 electrically connecting the electrodes 10. The electrode 10 has a rectangular shape and includes a first end and a second end for electrically connecting the self-capacitance change detecting unit along the extending direction of the electrode. In the present embodiment, the direction in which the electrodes extend is the direction in which the long sides of the rectangular electrodes are located, that is, the X-axis direction of the abscissa in the Cartesian coordinate system shown in FIG. The electrode 10 thus includes a first end SnL and a second end SnR. The self-capacitance change detecting unit 2 includes at least one variable collecting module 21 . The variable acquisition module 21 includes a constant current source 212 electrically connected to the first node a, a clamp circuit 213 and a charge transceiver detection circuit 211, and a second node b that is grounded. In the detection process for the one electrode 10, the first node a of the variable acquisition module 21 is electrically connected to the first end SnL of the electrode 10, and the second node b is electrically connected to the second end SnR of the electrode, and the second node is collected. After the self-capacitance change amount, the first node a of the variable acquisition module 21 is electrically connected to the second end SnR of the electrode 10, and the second node b is electrically connected to the first end SnL of the electrode 10 to collect the second self-capacitance. The amount of change. The clamp circuit 213 limits the potential of one end of the electrically connected electrode 10 to a constant potential, and the constant current source 212 supplies a constant current to the electrically connected electrode 10; the charge transceiving detection circuit 211 is electrically connected to the electrode 10 The self-capacitance changes, the charge is output to the electrode 10, and the charge output or the charge receiving amount is detected, and the charge is transferred. The output is the amount of self-capacitance change.

The clamp circuit defines a constant potential of one end of the electrically connected electrode as V1, and the constant current supplied from the constant current source to the electrically connected electrode is I, then V1/I=R should be satisfied, and R is a clamp The resistance of the electrode is electrically connected to the circuit and the constant current source.

As a method for detecting a self-capacitance change amount data for a touch panel and subsequently converting a self-capacitance change amount data into coordinate data, the present invention proposes a touch point coordinate data processing method based on the steps A to E for touch The self-capacitance change detecting method of the control panel, wherein the electrodes are sequentially arranged along a second direction perpendicular to the first direction. In the present embodiment, the first direction is the X-axis direction of the abscissa of the Cartesian coordinate system shown in Fig. 1, and the second direction is the ordinate Y-axis direction of the Cartesian coordinate system shown in Fig. 1. The method includes: F. When a touch point changes the self-capacitance of the K electrodes, the amount of self-capacitance change of the K pair with respect to the touch point is obtained, that is, the amount of self-capacitance change of 2K; G. Select 2K The largest one of the self-capacitance changes; the maximum self-capacitance change amount belongs to the T-th electrode along the second direction, and the maximum self-capacitance change amount is the first self-capacitance change of the T-th electrode , that is, DTU, the other self-capacitance change of the T-th electrode is the second self-capacitance change amount of the electrode, that is, DTV, so that the first self-capacitance change of the T-th electrode along the two-side electrodes in the second direction They are D(T+1)U, D(T+2)U,...,D(T+W1)U, and D(T-1)U,D(T-2)U,... , D(T-W2)U; the second self-capacitance change amounts are D(T+1)V, D(T-+2)V,..., D(T+W1)V, and D(T -1) V, D(T-2)V,...,D(T-W2)V, W1+W2+1=K; H. If the length of each electrode along the first direction is X0, along The length of the second direction is Y0, then the touch point described in step F is along the second direction coordinate Y, The touch point described in step F is along the first direction lateral coordinate X,

In the above method, the first and second self-capacitance change amount data collected by the variable acquisition module 21 are transmitted to a dedicated coordinate data processor unit, or data processing with coordinate data processing functions. Device. Based on the first and second self-capacitance change data collected by the present invention, the touch coordinate data can be obtained by the following specific techniques according to the above method. As shown in FIG. 1, it is assumed that the touch point affects three adjacent electrodes 10, The number in the intermediate position is the first self-capacitance change amount D3 and the second self-capacitance change amount D4 of the electrode 10 of Sn in the above two detections, wherein the first self-capacitance change amount D3 is the maximum value of all the changes. Then, the electrode numbered S(n-1) obtains the first self-capacitance change amount D1 and the second self-capacitance change amount D2 in the two detections. The two detections of the electrode 10 numbered S(n+1) obtain the first self-capacitance change amount D5 and the second self-capacitance change amount D6. If the length of each electrode 10 along the Y-axis direction of the Cartesian coordinate system is Y0, then the Y-axis coordinate of the touch point is If the total length of the electrode 10 on the X axis is X0, then the X-axis coordinate of the touch point is obtained by a proportional algorithm, specifically:

The present invention proposes an embodiment of implementing the variable acquisition module 21. As shown in FIG. 5, the clamp circuit 213 includes an operational amplifier OP, and the constant potential defined by the clamp circuit 213 is positively input by the operational amplifier OP. The input voltage of the terminal is controlled by Vf. Operational amplifier OP transmission and charge transmission and reception The feedback circuit formed by the capacitor Cc causes the potential Vf to form a clamp voltage at the inverting input terminal of the operational amplifier OP. The charge transceiving detection circuit 211 includes the operational amplifier OP serving as the clamp circuit 213, electrically connected to the charge transceiving capacitor Cc between the inverting input terminal and the output terminal of the operational amplifier OP, and electrically connecting the operational amplifier The AC-DC conversion sub-module 2111 at the output end of the OP. The current output terminal of the constant current source 212 and the inverting input terminal of the operational amplifier OP are electrically connected to the first node a. The constant current source 212 can use an existing current source product or a circuit that implements a current source function. When a charge flows into or out of the inverting input terminal of the operational amplifier OP, the operational amplifier OP can supply a charge through the charge transmitting and receiving capacitor Cc and quantize it in the form of an output voltage of the operational amplifier OP, the amount of change and the charge of the output voltage The transceiver capacitor Cc is inversely proportional. The output voltage change of the operational amplifier OP is converted into a digital quantity by the AC/DC conversion sub-module 2111, and output to the data processor for further processing.

The function of the SW circuit is reset. After each test, it is closed once, and the output voltage of the OP is restored to the initial value, and then the next test is performed.

In the above embodiment, in order to reset the circuit state after each detection, as shown in FIG. 5, a reset switch SW is further electrically connected between both ends of the charge transmitting and receiving capacitor Cc. After each detection, the reset switch SW is closed once, and the output voltage of the operational amplifier OP is restored to the initial value, and then the next detection is performed.

The rectangular electrodes of the present invention can also have a variety of equivalent structures. As shown in Fig. 6, a specific structure of an electrode is such that at least one vertex of the electrode 10 is cut away to form a straight segment oblique side 111, so that the electrode 10 is processed into a rectangular electrode 101 having a beveled edge 111. As shown in Fig. 7, another electrode 10 is specifically constructed such that at least one apex angle of the electrode 10 is cut away to form a circular arc edge 112, so that the electrode 10 is processed into a rectangular electrode 102 having a circular arc side 112. As shown in Figure 8, there is another type of electricity. The specific structure of the pole 10 is such that at least one side of the electrode 10 is formed with at least two grooves 113, and convex teeth 114 are formed between the two adjacent grooves 113, so that the electrode 10 is processed to have a serrated edge. Rectangular electrode 103.

The electrode 10 described in the present invention is made of indium tin oxide (ITO), metal mesh or carbon nanomaterial. As shown in Fig. 9, the electrode 10 is made of a metal mesh which is formed by lapping the wire 115 into a mesh, and the dotted line in Fig. 9 is equivalent to a metal mesh. Rectangular electrode shape.

Regarding the laying structure of the electrode, the self-capacitance sensing device further includes a substrate made of a resin synthetic film material or glass, and the electrode is attached to the substrate. The electrodes can be attached to the substrate by adhesion, etching, cutting or soldering techniques.

An electrode scanning detection method that can be used in the present invention is that the self-capacitance change detecting unit includes a set of variable collecting modules. The set of variable acquisition modules is electrically connected to the electrodes in a controlled manner according to the set timing, that is, the electrodes are electrically connected in a time-sharing manner to complete the self-capacitance change detection of each electrode. For example, as shown in FIG. 10, both ends of each electrode 10 shown in FIG. 1 are electrically connected to n pairs of the self-capacitance change detecting unit 2. The self-capacitance change detecting unit 2 sets a pair of controlled time-sharing electrical connections to control pairs c, d of each pair. Only one set of the variable acquisition module 21 is disposed in the self-capacitance change detecting unit 2. At the start of the detection, the controlled turns c, d are electrically connected first to a pair of turns of [1], which are electrically connected to the first end S1L and the second end S1R of the electrode 10 of the number S1, respectively. The variable acquisition module 21 electrically connects the first node a and the second node b to the controlled 埠c, d in accordance with the method described in the present invention, thereby completing the detection of the electrode 10 numbered S1, and detecting the structure. The variable acquisition module 21 outputs to the corresponding data processor unit. Thereafter, the controlled 埠c, d are electrically connected to the electrode 10 of the number S2 by the pair of turns of the sequence number [2] according to the set timing. And so on, the controlled 埠 connection number is [n] a pair of 埠, The number is the electrode 10 of Sn detected until all the electrodes 10 are detected, and the process of performing an electrode scan is completed. This type of scanning is the process of detecting all the electrodes with a set of variables.

In another electrode scanning detection mode, the number of the variable collection modules is less than the number of electrodes; each variable acquisition module is controlled to electrically connect one of the electrodes in a one-to-one manner according to a set timing, that is, time sharing Each electrode is electrically connected to the sub-region to complete the self-capacitance change detection of each electrode. The technical means is similar to the case of the above example, except that a plurality of sets of variable acquisition modules are used to perform time-division detection on a region composed of a plurality of electrodes, which is an electrode scanning method in a time division sub-region.

It is also possible to use a one-to-one electrode scanning detection method, and the variable acquisition module electrically connects the electrodes one-to-one. This scanning method can realize time-sharing scanning and time-division sub-area scanning.

The self-capacitance sensing device can be used to form a separate touch panel as an input device, or can be combined with a display device to form a touch display screen.

When the self-capacitance sensing device is combined with the display device, the self-capacitance sensing device is mounted in the liquid crystal display screen. As shown in FIG. 11, the liquid crystal display screen 3 includes a first liquid crystal substrate 31 and a second liquid crystal substrate 32, and a liquid crystal material 33, a pixel electrode 34 sandwiched between the first liquid crystal substrate 31 and the second liquid crystal substrate 32, The color filter layer 35 and the black matrix 36. The electrode is attached to an upper layer or a lower layer of the first liquid crystal substrate 31 or an upper layer or a lower layer of the second liquid crystal substrate 32. The electrode may be attached to the first liquid crystal substrate 31 or the second liquid crystal substrate 32 by a bonding, etching, cutting or soldering technique.

When the self-capacitance sensing device is combined with the display device, a structure integrated with the inherent circuit of the liquid crystal display screen in the same wafer may be employed in the circuit, and the self-capacitance sensing device is installed in the liquid crystal display screen. The liquid crystal display screen is controlled by a display driver circuit chip. Self-capacitance change A detection unit is integrated within the display drive circuit chip.

When the self-capacitance sensing device is combined with the display device, in order to prevent mutual interference between the electrode scanning detection and the liquid crystal scanning, the self-capacitance sensing device further includes a coordinated detection module. The self-capacitance sensing device is mounted in a liquid crystal display screen. The liquid crystal display screen is controlled by a display driving circuit. At this time, the display driving circuit may be in the same wafer as the self-capacitance change detecting unit, or may exist independently of each other in the respective wafers to which they belong. The coordinated detection module electrically connects the self-capacitance change detecting unit and the display driving circuit to complete the respective functions of the self-capacitance change detecting unit and the display driving circuit in a period of time and/or a sub-region without interfering with each other. The completion of the respective functions in the time-division period means that, within a set period of time, the self-capacitance change detecting unit is allocated to one or more time periods to complete the scan detection, in which the display driving circuit does not work, and the remaining time period is allocated to the display driver. The circuit completes the scan, and the self-capacitance change detecting unit does not work during this period. The completion of the respective functions of the sub-area means that the panel is divided into a plurality of non-coincident regions, and the self-capacitance change detecting unit and the display driving circuit are coordinated to perform scanning in different regions, that is, self-capacitance detection is performed for the same region. When scanning, the display drive scan is not performed, and when the display drive scan is performed, the self-capacitance detection scan is not performed.

10‧‧‧ electrodes

2‧‧‧Self-capacitance conversion detection unit

21‧‧‧Variable Acquisition Module

211‧‧‧Charge Transceiver Detection Circuit

212‧‧‧Constant current source

213‧‧‧Clamp circuit

{0}~{k}‧‧‧

A‧‧‧first node

B‧‧‧second node

R1~Rk‧‧‧Resistors

SnL‧‧‧ first end

SnR‧‧‧ second end

Claims (15)

A self-capacitance sensing device for a touch panel, comprising at least one electrode, and a self-capacitance change detecting unit electrically connecting the electrodes; wherein the electrode is rectangular, and comprises a self-capacitance change detecting unit for electrically connecting a first end and a second end along the extending direction of the electrode; the self-capacitance change detecting unit includes at least one variable collecting module; the variable collecting module includes a constant current source and a clamp electrically connected to the first node a bit circuit and a charge transceiving detection circuit, and a second node connected to the ground; in the detecting process for one electrode, the first node of the variable acquisition module is first electrically connected to the first end of the electrode, and the second node is electrically connected to the electrode After the first self-capacitance change is acquired, the first node of the variable acquisition module is electrically connected to the second end of the electrode, and the second node is electrically connected to the first end of the electrode to collect the second self a capacitance change amount; the clamp circuit limits a potential of one end of the electrically connected electrode to a constant potential, and the constant current source supplies a constant current to the electrically connected electrode; the charge transmission and reception detection Path from its output to the change in capacitance of the electrode connected to the output electrode of the electric charge, and detecting the charge amount of the charge output from the quantization capacitor variation. The self-capacitance sensing device for a touch panel according to claim 1, wherein: the clamping circuit defines a potential of one end of the electrically connected electrode to be a constant potential V1, and the constant current source is The constant current supplied by the electrically connected electrode is I, then V1/I=R should be satisfied, and R is the resistance of the electrode electrically connected to the clamp circuit and the constant current source. The self-capacitance sensing device for a touch panel according to claim 1, wherein: the clamp circuit includes an operational amplifier, and the constant potential defined by the clamp circuit is determined by the operation An input voltage control of the amplifier input terminal; the charge transceiving detection circuit includes the operational amplifier used as a clamp circuit, electrically connected to a charge transceiving capacitor between the inverting input terminal and the output terminal of the operational amplifier, and an electrical connection An AC/DC conversion sub-module of the output end of the operational amplifier; a current output end of the constant current source and an inverting input end of the operational amplifier are electrically connected to the first node. The self-capacitance sensing device for a touch panel according to claim 3, wherein a reset switch is further electrically connected between both ends of the charge transceiver capacitor. The self-capacitance sensing device for a touch panel according to claim 1, wherein at least one apex angle of the electrode is cut off to form a straight line oblique side, so that the electrode is processed with a hypotenuse Rectangular electrode. The self-capacitance sensing device for a touch panel according to claim 1, wherein at least one apex angle of the electrode is cut off to form a circular arc segment edge, so that the electrode is processed to have a circular arc edge Rectangular electrode. The self-capacitance sensing device for a touch panel according to claim 1, wherein at least one side of the electrode is processed with at least two grooves, and a convex portion is formed between two adjacent two grooves. The teeth are such that the electrodes are machined into rectangular electrodes with serrated edges. The self-capacitance sensing device for a touch panel according to claim 1, wherein the electrode is made of indium tin oxide, a metal mesh or a carbon nanomaterial. The self-capacitance sensing device for a touch panel according to claim 1, wherein: further comprising: a substrate made of a resin synthetic film material or made of glass, the electrode being attached to the substrate. The self-capacitance sensing device for a touch panel according to claim 1, wherein: the self-capacitance sensing device is installed in a liquid crystal display screen; the liquid crystal display screen includes a first liquid crystal substrate and a second a liquid crystal substrate, and a liquid crystal material, a pixel electrode, a color filter layer, and a black matrix sandwiched between the first liquid crystal substrate and the second liquid crystal substrate; wherein the electrode is attached to an upper layer or a lower layer of the first liquid crystal substrate, or The upper layer or the lower layer of the liquid crystal substrate. The self-capacitance sensing device for a touch panel according to claim 1, wherein: the self-capacitance change detecting unit comprises a set of variable collecting modules; and the set of variable collecting modules is controlled according to a setting. The timing is electrically connected to the electrodes in turn, that is, the electrodes are electrically connected in a time-sharing manner to complete the self-capacitance change detection of each electrode. The self-capacitance sensing device for a touch panel according to claim 1, wherein: the number of the variable acquisition modules is less than the number of electrodes; and each variable acquisition module is controlled according to a set timing. A part of all the electrodes are electrically connected one-to-one in sequence, that is, the electrodes are electrically connected in a time division manner to complete the self-capacitance change detection of each electrode. The self-capacitance sensing device for a touch panel according to claim 1, wherein the variable acquisition module electrically connects the electrodes one-to-one. The self-capacitance sensing device for a touch panel according to claim 1, wherein: the self-capacitance sensing device is installed in a liquid crystal display screen; the liquid crystal display screen is controlled by a display driving circuit chip; The self-capacitance change detecting unit is integrated in the display driving circuit chip. The self-capacitance sensing device for a touch panel according to the first aspect of the invention, further comprising: a coordinated detection module; the self-capacitance sensing device is installed in a liquid crystal display screen; the liquid crystal display screen is Display drive The control circuit module electrically connects the self-capacitance change detecting unit and the display driving circuit, so that the self-capacitance change detecting unit and the display driving circuit complete respective functions in a time-division and/or sub-region without interfering with each other.