JPH06187084A - Coordinate input device - Google Patents

Abstract

PURPOSE:To provide the coordinate input device for detecting a touch position in a film resistance analog system coordinate input device at high speed without requiring any switching operation. CONSTITUTION:Concerning a coordinate input device 10, two electrodes 5 and 6 composed of uniform electrode films are faced each other, voltage distribution is formed by impressing a voltage for detection to one electrode 5 with the electrode as an impressing electrode, a voltage to be generated at the time of partially touching both of electrodes from the edge part of the other electrode 6 is detected with the electrode as a detecting electrode and the position (point P) touching both of electrodes 5 and 6 each other is calculated. Further, concerning this coordinate input device 10, amplifier circuits 11 and 12 provided with an amplification factor in inverse proportion to film resistance provided for the detecting electrode 6 are respectively connected to two detection output terminal parts O3 and O4 provided on both sides of the detecting electrode 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device, and more particularly, to a coordinate input device which has good operability and is advantageous in saving space, and in particular, as a handwriting input device capable of coping with high speed. It is about.

[0002]

2. Description of the Related Art As coordinate input devices, devices having various configurations have been proposed. Among them, a membrane resistance analog type coordinate input device is known as a coordinate input device as a pointing device that can be applied to a wide range of applications and can also be used for handwriting input.

2A to 2C are views for explaining a conventional structure of such a membrane resistance analog coordinate input device,
Basically, two electrodes with uniform electrode film are made to face each other, one electrode is used as an application electrode and a detection voltage is applied to the electrode to form a voltage distribution, and the other electrode is used as a detection electrode. By detecting the voltage generated when a part of both electrodes are brought into contact with each other from the end portion of the electrode, it is determined whether or not the two electrodes are brought into contact with each other (touch sensor), and both electrodes are Are configured to calculate the coordinates of the positions where the two touch each other.

In the film resistance analog type coordinate input device, as shown in FIG. 1A, along the vicinity of two sides a and b of the first transparent electrode film 1 facing each other, for example, in the Y direction. 2 conductors 3 and 3'opposed to each other are provided as a Y-direction electrode 5 and, as shown in FIG. 1B, in the vicinity of two opposing sides c and d of the second transparent electrode film 2. For example, two conductors 4 and 4'opposing each other in the X direction are provided as the X direction electrodes 6, and both electrodes 5 and 6 are provided in each X direction as shown in FIG. 1C. The conductors 4 and 4'and the conductors 3 and 3'in the Y direction are laminated and arranged at right angles to each other, and a predetermined uniform interval L is provided between the electrodes. The films are arranged so as to face each other.

In the example shown in FIG. 1C, the electrode film 1 having the Y-direction electrode is used as an application electrode, and the electrode film 2 having the X-direction electrode is used as a detection electrode. Then, the wiring E1 connected to the end of the one conductor 3 of the applying electrode 5
Is a high-potential power supply voltage via an appropriate switch means SW1,
For example, the wiring E2 connected to Vcc or placed in an open state including high impedance and connected to the end of the other conductor 3 ′ is supplied with a low potential power supply voltage, for example, a low potential power supply voltage, through an appropriate switch means SW2. It is designed to be connected to GND or the detection terminal D2.

On the other hand, the wiring E3 connected to one end of the conductor 4 of the detection electrode 6 is connected to a low-potential power supply voltage, for example, GND through an appropriate switch means SW3.
The wiring E4 connected to the detection terminal D1 and connected to the end of the other conductor 4 ′ is connected to an appropriate switch means SW4.
It is configured to be connected to a high-potential power supply voltage, for example, Vcc, or to be in an open state including high impedance.

In such a circuit configuration, for example, when detecting a coordinate in the Y direction, the switch SW1 is operated to connect the wiring E1 to a high potential power supply voltage, for example, Vcc, and at the same time, to switch the switch. Activate the means SW2,
The wiring E2 is connected to a low potential power supply voltage, for example, GND. On the other hand, by operating the switch SW3, the wiring E3
Is connected to the detection terminal D1, and at the same time, the switch means SW4 is operated to bring the wiring E4 into a high impedance state.

When an arbitrary place of the coordinate input device is pressed to make both electrodes touch each other, both electrodes are brought into conduction at the contact portion, and the touch position of the Y-direction electrode resistance is applied to the detection terminal D1. A voltage level Vout obtained by dividing the applied voltage Vcc by the division ratio in
The Y coordinate of the touch portion position is calculated as Vout / Vcc.

However, in this case, it is necessary that the electrode film is formed uniformly. Next, when the X coordinate at the same position is detected and calculated, the respective switches are switched, and the switch SW1 is switched to bring the wiring E1 into a high impedance state, and at the same time,
The switch means SW2 is switched to connect the wiring E2 to a low potential power supply voltage, for example, GND.

On the other hand, the switch SW3 is operated to connect the wiring E3 to the detection terminal D2, and at the same time, the switch means SW4 is operated to connect the wiring E4 to a high potential power supply voltage, for example, Vcc. As a result, a voltage level Vout obtained by dividing the applied voltage Vcc by the division ratio of the X-direction electrode resistance at the touch position is output to the detection terminal D2, whereby the X coordinate of the touch portion position is Vout / Vcc. Is calculated as

[0011]

However, in such a conventional membrane resistance analog coordinate input device, in order to detect one position and calculate it as a two-dimensional coordinate value in the X and Y directions, As described above, it is necessary to switch between the application electrode and the detection electrode when calculating the X-direction coordinate and when calculating the Y-direction coordinate, which slows down the detection speed and hinders improvement of the detection speed. It was.

That is, in such a conventional membrane resistance analog type coordinate input device, as described above, each switch SW is operated when calculating the X-direction coordinate and when calculating the Y-direction coordinate.
Since it requires an operation to switch the switch, it takes time, and at the same time, each circuit has a capacity.When each switch is switched, wait for the voltage to rise to the specified voltage value before performing the detection operation. So you have to do
Since the waiting time is required for each switching operation, this also causes the calculation speed to slow down.

Therefore, an object of the present invention is to improve the above-mentioned drawbacks of the prior art and to detect a touch position at high speed in the membrane resistance analog coordinate input device without requiring a switching operation. Is provided.

[0014]

In order to achieve the above-mentioned object, the present invention adopts the technical constitution as described below. That is, two electrodes composed of uniform electrode films are opposed to each other, one electrode is used as an application electrode to apply a detection voltage to the electrode to form a voltage distribution, and the other electrode is used as a detection electrode. In the coordinate input device that calculates the position where both electrodes are in contact with each other by detecting the voltage generated when part of both electrodes are in contact with each other from the end of In the coordinate input device, the two detection output end portions provided in are connected to an amplification circuit having an amplification factor that is inversely proportional to the film resistance of the detection electrode.

[0015]

Since the coordinate input device according to the present invention has the above-mentioned basic structure, in the conventional operation for detecting and calculating a two-dimensional coordinate value, the X direction There is no need to separately calculate while calculating the coordinates and performing the Y-direction coordinate switching operation, and the X position of any touch position can be calculated.
Since the directional coordinate and the Y-direction coordinate are instantly obtained by one detection operation, high-speed detection is possible.

Therefore, it can effectively function as a handwriting coordinate input device for which high speed is required. Furthermore,
Since the detection circuit configuration of the coordinate input device according to the present invention is simple and the occupied area can be reduced, it is possible to downsize the coordinate input device itself.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples of the coordinate input device according to the present invention will be described in detail below with reference to the drawings. That is, in FIG.
1 is a block diagram showing a configuration of a specific example of a coordinate input device 10 according to the present invention, specifically, two electrodes 5 and 6 formed of uniform electrode films are opposed to each other, and one electrode This occurs when 5 is an application electrode and a detection voltage is applied to the electrode to form a voltage distribution, and the other electrode 6 is used as a detection electrode to bring parts of both electrodes from the end of the electrode into contact with each other. In the coordinate input device 10 for calculating the position (point P) where the electrodes 5 and 6 are in contact with each other by detecting the applied voltage, two detection output terminals provided on both sides of the detection electrode 6 are detected. A coordinate input device 10 is shown in which amplification circuits 11 and 12 having an amplification factor inversely proportional to the film resistance of the detection electrode 6 are connected to the portions O3 and O4, respectively.

That is, in the coordinate input device according to the present invention, the changeover switch for detecting the X-coordinate and the Y-coordinate, which has been a problem in the related art, is eliminated, and the X-axis is measured by one measurement operation.
The coordinate and the Y coordinate are configured to be calculated and detected at the same time, and the basic configuration thereof is, as described above, two application input end portions O1 provided on both sides of the application electrode 5. O
2 is applied with an applied voltage V0 having a predetermined voltage level, and at the detection end of the detection electrode 6, the amplification circuit 1
1 and 12 are provided, and the position (point P) where the applying electrode 5 and the detecting electrode 6 contact each other in the detecting electrode 6 is
Amplifier circuits 11 and 12 for calculating and detecting the divided voltage values V _XA and V _XB corresponding to the positions occupied by the entire length of the detection electrode 6 in the width direction are provided, and further, the respective amplifier circuits 11 are provided. , 12 are output to predetermined arithmetic circuits 13, 1
4, and the X coordinate and the Y coordinate of the point P are simultaneously calculated and obtained.

The amplifier circuit 1 used in the present invention
The circuits 1 and 12 may be any circuits as long as they have a circuit configuration having an amplification factor that is inversely proportional to the film resistance of the detection electrode 6, but inverting amplification type operational amplifiers OP1 and OP2 are preferably used. Things are desirable. That is, in the present invention, the first amplifier circuit 11 connected to the first detection output end O4 provided at one end c of the detection electrode 6 and the other end of the detection electrode 6 are connected. The second amplifier circuit 1 connected to the second detection output end O3 provided in the part d
2 and a first arithmetic circuit 13 and a second arithmetic circuit 14 to which both the outputs of the first and second amplifier circuits 11 and 12 are individually input, and the first arithmetic circuit is provided. Circuit 13
, The first of the formula V _XB / (V from the output to the other partial pressure value V _XA in the X direction amplifying circuit 12 in the X direction divided voltage value V _XA and the second outputs of the amplifier circuit 11 _XA + V _XB ) is performed to calculate the coordinates on the detection electrode side, that is, the X coordinate value, and the second arithmetic circuit 14 is configured to operate the first amplifier circuit 11 output equation -R _P / R · amplifying circuit 12 in the X direction divided voltage value V _XA and the second from the other partial pressure value V _XA in the X direction to be output to _{(V XA · V XB) /} ( V _XA + V _XB ) / 1 / V
The calculation of ₀ is executed to calculate the coordinate on the side of the applied electrode, that is, the Y coordinate value.

Here, R is the resistance value of the resistor connected between the output terminal of the amplifier circuit and the inverting input terminal, R _P is the resistance value of the detection electrode, and V _XA is the resistance value of the first amplifier circuit. Output value, V
_XB is the output value of the second amplifier circuit, and V ₀ is the applied voltage to the applied electrode. The reason why the inverting amplification operational amplifiers OP1 and OP2 are used in the coordinate value arithmetic processing circuit according to the present invention is that the resistance connected to the inverting input terminal of the inverting amplification operational amplifier OP is the resistance of the electrode film. Value, and an appropriate resistance R connected between the membrane resistance value and the output of each of the operational amplifiers OP1 and OP2 and the inverting input terminal.
Is due to the fact that the applied voltage V0 applied to the applying electrode 5 is inversely proportional to the outputs V _XA and V _{XB of the} operational amplifier OP.

Next, the coordinate input device 1 according to the present invention.
An example of a calculation method for obtaining the X coordinate and the Y coordinate of the contact point (P) on the electrode film at 0 will be described. First, a predetermined applied voltage Vo is applied between the terminals of the input voltage wirings E1 and E2 connected to the applied voltage input terminal portions O1 and O2 of the applying electrode 5.
Is applied, and the desired point P is pressed to bring parts of the application electrode 5 and the detection electrode 6 into contact with each other so that the electrodes 5 and 6 are electrically connected.

In this state, the Y coordinate at point P
Is the voltage V at the contact point P _YUsing V_Y/
V₀Required from. Where V_YThe procedure for
For example, arithmetic processing is performed as follows. That is, this
Output V of the amplifier circuits 11 and 12_XA, V_XBBut V_XA= -R / R_X・ V_Y--- (1) V_XB= -R / R_1-X・ V_YSince it is expressed as --- (2), R_X= -R / V_XA・ V_Y--- (3) R_1-X= -R / V_XB・ V_Y--- (4).

[0023] Here, since the total resistance value of the detection electrode 6 is When _{R P R P = R X +} R 1-X ---- (5), R P = -R · V Y · (1 / V _XA + 1 / V _XB ) --- (6).

[0024] _{Therefore, V Y = -R P / R} · (V XA ·
V _XB ) / (V _XA + V _XB ) --- (7). Therefore, the coordinate value (Y coordinate) on the application electrode side = V _{Y
/ V 0 = -R P / R} · (V XA · V XB) / (V XA + V XB) · 1 /
It represented V ₀ ---- (8).

That is, the coordinate value (Y coordinate) on the side of the applying electrode is
It can be seen that the calculation is performed by causing the second calculation circuit 14 to execute the calculation of Expression 8 above. Next, the coordinate value (X coordinate) on the detection electrode side can be calculated from the above equations 1 and 2 as follows: Coordinate value on the detection electrode side (X coordinate) = R _X / R _X + R _1-X = V _XB / (V _XA + V _XB ) --- (9).

That is, the coordinate value (X coordinate) on the detection electrode side is
It can be seen that the calculation is performed by causing the first calculation circuit 13 to execute the calculation of Expression 9 above.

[0027]

Since the coordinate input device according to the present invention employs the technical configuration as described above, the switching operation when measuring each voltage of the application electrode and the detection electrode is not necessary, and the X direction and the Y direction. Since two coordinates with the direction can be detected completely in parallel and at the same time, high speed detection is possible.

Further, even if the touch panel is constructed so that it is possible to detect a plurality of points obtained by dividing the detection electrode, it is possible to deal with the touch panel without deteriorating the detection speed. . Therefore, it can effectively function as a handwritten coordinate input device for which high speed is required.

Further, since the detection circuit configuration of the coordinate input device according to the present invention is simple and the occupied area can be reduced, it is possible to downsize the coordinate input device itself.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a specific example of a coordinate input device according to the present invention.

FIG. 2 is a diagram showing a configuration example of a conventional coordinate input device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrode film 2 ... Electrode film 3, 3 '... Conductor 4, 4' ... Conductivity 5 ... Application electrode 6 ... Detection electrode 10 ... Coordinate input device 11, 12 ... Amplification circuit 13, 14 ... Arithmetic circuit

Claims (3)

[Claims] 1. A pair of electrodes composed of uniform electrode films are opposed to each other, one electrode is used as an application electrode to apply a detection voltage to the electrode to form a voltage distribution, and the other electrode is used as a detection electrode. In the coordinate input device that calculates the position where both electrodes are in contact with each other by detecting the voltage generated when the parts of both electrodes are in contact with each other from the end of the electrode A coordinate input device characterized in that an amplifier circuit having an amplification factor inversely proportional to the film resistance of the detection electrode is connected to two detection output ends provided on both sides of the electrode. 2. The coordinate input device according to claim 1, wherein the amplification circuit is an inverting amplification type operational amplifier. 3. A first amplifier circuit connected to a first detection output end provided at one end of the detection electrode, and a second detection circuit provided at the other end of the detection electrode. A second amplifier circuit connected to the output end and a first arithmetic circuit and a second arithmetic circuit to which both of the first and second amplifier circuits are individually input are provided. the first operation _{circuit, -R P / R · (V} XA · V XB) / (V XA + V XB) · 1 / V
The calculation of ₀ is executed to calculate the coordinates on the side of the applied electrode, and the second calculation circuit executes the calculation of V _XB / (V _XA + V _XB ) to calculate the coordinates on the side of the detection electrode. The coordinate input device according to claim 1, wherein the coordinate input device is configured to calculate. Here, R is the resistance value of a resistor connected between the output terminal of the amplifier circuit and the inverting input terminal, R _P is the resistance value of the detection electrode, V _XA is the output value of the first amplifier circuit, V _XB is the output value of the second amplifier circuit, and V ₀ is the applied voltage to the applied electrode.