JPH08328729A - Coordinate detector - Google Patents

Abstract

PURPOSE: To perform high-speed coordinate detection without influence by the parasitic capacitance of wiring relating to a coordinate detector for detecting a coordinate by detecting the short-circuited position of orthogonal wiring. CONSTITUTION: For the coordinate detection of a short-circuited part, the wiring for detecting an (x) axis coordinate is connected to a prescribed first reference voltage REF1, the wiring for detecting a (y) axis coordinate is connected to a prescribed second reference voltage REF2 different from the REF1, a current when the wiring for detecting the (x) axis coordinate and the wiring for detecting the (y) axis coordinate are short-circuited is detected and the coordinate is detected. Thus, the need of charging and discharging the wiring is eliminated at the time of detecting the coordinate and detection time is short. Also, since the need of changing the voltage of the wiring is eliminated at the time of scanning the wiring for the coordinate detection, unrequired electromagnetic radiation is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detecting device,
Particularly, the present invention relates to a coordinate detection device that detects a two-dimensional coordinate by detecting a short circuit position of orthogonal wiring.

[0002]

2. Description of the Related Art A conventional coordinate detecting device for detecting two-dimensional coordinates by short-circuiting orthogonal wiring groups scans one wiring group, applies a voltage to the wirings in sequence, and detects the voltage of the other wiring group. To detect the coordinates. FIG. 3 shows an example of a conventional coordinate detecting device. FIG. 3 schematically shows the configuration of an apparatus for detecting 4 × 4 coordinates.

Referring to FIG. 3, the coordinate detecting device comprises a sensor panel 60 and an encoder 6 for detecting the x-axis coordinate.
2, composed of a shift register 63 for scanning the y-axis,
The wirings 64, 65, 66, 67 of the sensor panel are connected to the encoder 62, and the wirings 68, 69, 70, 71 are connected to the shift register 63.

FIG. 4 is a perspective view for explaining the schematic structure of the sensor panel 60. Referring to FIG. 4, a plurality of wirings 52, 5 made of a conductive material are provided on the surfaces of the two insulating plates 50, 51 arranged in parallel with each other and facing each other.
3, 54 and wirings 55, 5 orthogonal to these wirings
6, 57 are arranged.

Insulating plates 50 and 51 are spaced apart from each other by a predetermined distance so that the wirings arranged on the respective surfaces do not usually short-circuit with each other. Wirings facing each other at the pressed portion come into contact with each other and short-circuit.

Referring again to FIG. 3, the encoder 62 has a 4-input 2-bit output and outputs a voltage indicating that to the signal SNS when one of the four input terminals receives an input. Then, to the XPOS, the number of the input terminal having the input is output to the wirings 72 and 73 according to the combination shown in Table 1 (that is, XPOS is the position information).

[0007]

[Table 1]

In Table 1, V72 is the voltage of the wiring 72 ("H" is high level, "L" is low level), and V72 is V7.
Reference numeral 3 represents the voltage of the wiring 73.

The detection of the coordinates is performed by the following processing procedure. FIG. 5 is a timing chart for explaining the operation of the conventional example shown in FIG.

In FIG. 5, CLKY is a clock signal input to the shift register 63, and SPY is a start pulse that means the start of y-axis scanning. Also, V68
To V71 indicate the voltages of the wirings 68 to 71 connected to the outputs 1 to 4 of the shift register 63, respectively. And V64 to V67 are encoders 62
The voltages of the wirings 64 to 67 connected to the input 1 to the input 4 are shown. SNS is a signal indicating that there is an output and an input of the encoder 62,
V72 and V73 are wiring 7 which is the output of the encoder 62
The signal voltages of 2 and 73 are shown.

Here, in the conventional example shown in FIG.
It is assumed that the wires 66 and 69 of the sensor panel 60 are short-circuited at the position indicated by 1, that is, the position of the coordinates (3, 2).

The shift register 63 receives the start pulse signal SPY for starting the y-axis scanning, and then, in synchronization with the clock signal CLKY, the wiring 68 for detecting the y-axis coordinates.
Voltages are sequentially output to 69, 70, 71.

Further, the encoder 62 detects one of the wirings 64, 65, 66, 67 for detecting the x-axis coordinate which is short-circuited with the wiring for detecting the y-axis coordinate selected by the shift register 63, and the coordinate value is detected. Convert to.

In this example, since there is a short circuit at the coordinate (3, 2), when the y-axis coordinate detecting wiring 69 is selected, a voltage appears on the x-axis detecting wiring 66 and the encoder 62 detects the coordinate. The signal SNS indicating that this has been done and the coordinate value XPOS of the x-axis are output to the wirings 72 and 73 according to Table 1. In this case, V72 indicating the coordinate 3 on the x-axis is “L”,
V73 is in the "H" state.

[0015]

In the case of a coordinate input device, particularly a coordinate input device intended for manual input, the device inevitably has a certain size. In this case x
There has been a problem that the length of the axis coordinate detection wiring and the y-axis coordinate detection wiring becomes long, a time constant is provided due to the parasitic capacitance and resistance of each wiring, and it takes time to detect.

In particular, in the conventional coordinate detecting device shown in FIG. 3, it is necessary to charge the parasitic capacitance of the wiring every time the wiring outputting the voltage is switched by scanning the y-axis coordinate detecting wiring.

In order to detect the coordinates of the short-circuited portion, it is necessary to scan the y-axis coordinate detection wiring at least once. When the y-axis coordinate detection wiring is scanned, the parasitic capacitance of the wiring is charged / discharged. Time cannot be ignored.

Further, in the above-mentioned conventional coordinate detecting device, when scanning the y-axis coordinate detecting wiring, it is necessary to change the voltage of the coordinate detecting wiring at a high speed. You will receive radiation.

Therefore, an object of the present invention is to solve the above problems and to detect a coordinate by detecting a short-circuited position of an orthogonal wiring. It is to provide a coordinate detection device that enables to perform.

[0020]

In order to achieve the above object, the present invention provides a first plane arranged parallel to each other on a first plane.
And a second wiring group arranged on the second plane opposite to the first plane in parallel to each other at right angles to the wiring group 1, and the first and second wiring groups are provided. The wiring group is normally electrically insulated from each other, and the wiring of the first wiring group and the wiring of the second wiring group are in contact with each other at a position where they are pressed, resulting in a short-circuited state. In the two-dimensional coordinate detection device for detecting a coordinate value by detecting the above, one end of the first wiring group is commonly connected to a predetermined first reference voltage, and one end of the second wiring group has a predetermined second reference voltage. Of the wirings of the first wiring group and the wirings of the second wiring group, which are commonly connected to the reference voltage of the first wiring group, a current flows in the wiring which is in a short-circuit state due to contact with each other, and the current is detected to obtain coordinate values. A coordinate detecting device is provided.

In the present invention, preferably the first
The voltage value of the reference voltage is higher than the voltage value of the second reference voltage.

In the present invention, preferably, the first
Each wiring of the wiring group of 1 is connected to the first reference voltage via a resistance, and each wiring of the second wiring group is connected to the second reference voltage via a resistance, and the first wiring A current flows in a wire of the group of wires and a wire of the second wire group that is in contact with each other and is in a short-circuited state, and a coordinate value is obtained based on a voltage appearing in the resistor connected to the wire. And

In the present invention, preferably the first
Of the wirings of the wiring group, a current flows through the resistance connected to the wiring, and a wiring whose voltage is different from the first reference voltage is searched for, and the second wiring group is searched. Among the wirings, the current flows through a resistance connected to the wiring, and a wiring having a voltage different from the second reference voltage is searched for to detect a short-circuited wiring.

In the present invention, preferably the first
Between the first reference voltage and the second reference voltage, which is higher than the intermediate voltage between the first reference voltage and the second reference voltage, and the first reference voltage. A fourth reference voltage, which is a voltage lower than the intermediate voltage between the reference voltage and the second reference voltage, is provided, and among the wirings of the first wiring group, the wiring having a voltage lower than the fourth reference voltage is connected. Explore,
The wiring of the second wiring group is searched for a wiring having a voltage higher than the fourth reference voltage, and a short-circuited wiring is detected.

In the present invention, preferably the first
A first switch group for switching and connecting a voltage at one end of the resistor connected to each wiring of the second wiring group to the negative input terminal of the first comparator, and for each wiring of the second wiring group A second switch group for switching and connecting the voltage at one end of the resistor connected to the wiring to the positive input end of the second comparator, and the positive input end of the first comparator includes the third switch group. Reference voltage is input, and the fourth reference voltage is input to the negative input terminal of the second comparator to sequentially close the first and second switch groups in synchronization with a predetermined clock. The first and second control means for supplying a predetermined switching control signal,
The wiring in the short-circuit state is detected based on the output voltage of the comparator and the clock.

[0026]

According to the present invention, the x-axis coordinate detection wiring is set to the predetermined first reference voltage REF1, and the y-axis coordinate detection wiring is set to RE.
Connected to a predetermined second reference voltage REF2 different from F1,
Since the x-axis coordinate detection wiring and the y-axis coordinate detection wiring are configured to detect the coordinates by detecting the current when the wiring is short-circuited, the parasitic capacitance of the coordinate detection wiring when detecting the coordinates of the short-circuited portion Since the x-coordinate and the y-coordinate can be detected at the same time without charging / discharging, the detection time is greatly shortened. Further, according to the present invention, it is not necessary to change the voltage of the coordinate detection wiring at the time of coordinate detection, and therefore, generation of unnecessary electromagnetic radiation from the coordinate detection wiring is avoided.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention.
With reference to FIG. 1, in the present embodiment, a sensor panel 1, an x-axis coordinate detection circuit 2, a y-axis coordinate scanning circuit 3, comparators 4 and 5, a first reference voltage REF1 (output voltage is VREF
1) and the second reference voltage REF2 (output voltage is VREF
The voltage dividing resistors 6, 7 and 8 for generating the third reference voltage 44 and the fourth reference voltage 46 are inserted between 2).

Also in this embodiment, the sensor panel 1
Has a structure as shown in FIG.

X-axis coordinate detection wirings 19, 20, 21, 2
2 and the y-axis coordinate detection wirings 31, 32, 33, and 34 are electrically insulated from each other, but are connected to the x-axis coordinate detection wiring at a position pressed from the surface of the sensor panel 1. The y-axis coordinate detection wiring is short-circuited.

Here, for the sake of explanation, it is assumed that the position indicated by reference numeral 35 in FIG. 1 is pushed and the x-axis coordinate detection wiring 21 and the y-axis coordinate detection wiring 32 are short-circuited.

X-axis coordinate detection circuit 2 and y-axis coordinate detection circuit 3
Have the same configuration, and each of the coordinate detection wirings 19 to
22 and 31 to 34 are provided with resistors 15 to 18 and 27 to 30 for current detection one by one, and a switch 11 for switching the wiring for detecting voltage by the first and second shift registers 9 and 10. -14 and 23-26.

Resistors 15-18, 27-30 for current detection
The resistance values of all are the same.

The positive input of the first comparator 4 is the third reference voltage VREF3, and the negative input of the second comparator 5 is the fourth reference voltage VREF4. The resistance value of the voltage dividing resistors 6, 7 and 8 is the third reference voltage V
REF3 is VREF1 and (VREF1 + VREF2)
/ 2, and the fourth reference voltage VREF4 becomes
It is set to be a voltage between (VREF1 + VREF2) / 2 and VREF2.

Referring to FIG. 1, coordinates (3,
When a short circuit occurs at the position 2), the wirings 19, 20, 22, 31, 33, and 34 of the coordinate detection wirings do not flow in the current detection resistors, so the wirings 19, 20, and 22 are not 1 reference voltage VREF1 and wirings 31, 33, 34 are second
A current flows through the reference voltage VREF2 and the wirings 21 and 32 due to a short circuit, and the current detection resistors 17 and 28 are equal to each other, which is (VREF1 + VREF2) / 2.

The coordinate detecting operation in this embodiment will be described below with reference to the timing chart of FIG. In FIG. 2, CLKX and CLKY are signals input to the clock terminals CLKX and CLKY of the first and second shift registers 9 and 10, and SPX and SPY are SPX and SPY of the first and second shift registers 9 and 10. The signals to be input are a start pulse signal for starting scanning on the x-axis and a start pulse signal for starting scanning on the y-axis.

V36 to V39 and V40 to V43 are the first,
The outputs of the second shift registers 9 and 10 indicate the voltages of the wirings 36 to 39 and 40 to 43 which are signal lines for controlling the opening and closing of the switches 11 to 14 and 23 to 26 connected to the outputs. V45 is the voltage of the wiring 45, that is, the voltage of the negative input terminal of the first comparator 4, and V47 is the voltage of the wiring 47, that is, the voltage of the positive input terminal of the second comparator 5.

V44 and V46 are the third and fourth reference voltages VREF3 and VREF4 generated by the resistors 6, 7 and 8, respectively.
, And SNSX and SNSY represent the output voltages of the first and second comparators 4 and 5, respectively.

In the present embodiment, the actual coordinate detection is performed simultaneously on the x-axis and the y-axis, but the x-axis and the y-axis will be described separately for the sake of clarity.

Referring to FIG. 2, the first shift register 9
When the start pulse signal SPX having a width of one clock is input while the clock signal CLKX is input to the switch control wirings 36 to 39, the voltage is output in order of the switch control wirings 36 to 39 (see V36 to V39).

The switches 11-14 have this voltage (V36-
When V39) is received, the coordinate detection wirings 19 to 22 connected to each and the wiring 45 connected to the negative input of the first comparator 4 are sequentially connected.

Therefore, the voltage V45 of the wiring 45 is as shown in FIG.
As shown in, when the voltage V38 for controlling the switch 13 connected to the wiring 21 corresponding to the X coordinate 3 is output, it becomes (VREF1 + VREF2) / 2, and at other times, it becomes the first reference voltage VREF1.

Since the third reference voltage VREF3 is input to the positive input of the first comparator 4, the output SNSX of the first comparator 4 has a voltage ("H" when the x coordinate 3 is selected). "Level) is output, and the x coordinate is detected.

The detection of the y-coordinate is also performed as follows in the same manner as in the case of the x-coordinate.

When the start pulse signal SPY having a width of 1 clock is input while the clock signal CLKY is being input to the second shift register 10, the voltage is output in order of the switch control wirings 40 to 43 every clock thereafter ( V
40-V43).

The switches 23 to 26 have this voltage (V40 to
When receiving V43), the coordinate detection wirings 31 to 34 connected to each of them and the wiring 47 connected to the positive input of the second comparator 5 are sequentially connected.

Therefore, the voltage V47 of the wiring 47 is as shown in FIG.
As shown in, when the voltage V41 for controlling the switch 24 connected to the wiring 32 indicating the y-coordinate 2 is output, it becomes (VREF1 + VREF2) / 2, and at other times, it becomes the second reference voltage VREF2.

As a result, the voltage ("H" level) is output to SNSY only when the Y coordinate 2 is selected, and the y coordinate is detected.

Since the detection of the x coordinate and the detection of the y coordinate do not interfere with each other, they can be performed simultaneously.

Although the present invention has been described with reference to the above embodiments, the present invention is not limited to the above embodiments,
As a matter of course, it includes various aspects according to the principle of the present invention.

[0051]

As described above, according to the present invention,
Since there is no charging / discharging of the parasitic capacitance of the coordinate detection wiring when detecting the coordinates of the short-circuited portion, and the x-coordinate and y-coordinate can be detected at the same time, the detection time can be significantly shortened. .

Further, according to the present invention, in the coordinate detection,
It is not necessary to change the voltage of the coordinate detection wiring, which has the effect of avoiding generation of unnecessary electromagnetic radiation from the coordinate detection wiring.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a timing diagram for explaining the operation of the embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining a configuration of a conventional example.

FIG. 4 is a perspective view illustrating a configuration of a sensor panel.

FIG. 5 is a timing chart for explaining the operation of the conventional example.

[Explanation of symbols]

 1 Sensor Panel 2 x-axis coordinate detection circuit 3 y-axis coordinate detection circuit 4 x-axis comparator 5 y-axis comparator 6 to 8 reference voltage generation resistor 9 first shift register 10 second shift register 11 to 14 switch 15 -18 Current detection resistance 19-23 Coordinate detection wiring 23-26 Switch 27-30 Current detection resistance 31-34 Coordinate detection wiring 35 Coordinate location 36-43 Switch control wiring 44 Third reference voltage 45 Wiring 46 Fourth reference voltage 47 Wiring 50, 51 Insulator plate 52-57 Coordinate detection wiring 60 Sensor panel 61 Short circuit location 62 Encoder 63 Shift register 64-67 x Coordinate detection wiring 68-71 y Coordinate detection wiring 72 x Axis coordinate (lower) 73 x-axis coordinate (upper)

Claims (6)

[Claims] 1. A first wiring group arranged on a first plane in parallel with each other, and a second wiring group facing the first plane and parallel to each other orthogonal to the wiring group 1. Second arranged
Wiring groups of the first wiring group, and the first and second wiring groups are usually electrically insulated from each other and correspond to the pressed portions, and the wirings of the first wiring group and the second wiring group are provided. In a two-dimensional coordinate detection device for detecting a coordinate value by detecting a position where a wiring of a group is in contact with each other and is in a short-circuited state, one end of the first wiring group is commonly connected to a predetermined first reference voltage. One end of the second wiring group is commonly connected to a predetermined second reference voltage, and one of the wirings of the first wiring group and the wiring of the second wiring group is in contact with each other to be in a short-circuited state. Current flows through the wiring,
A coordinate detection device characterized by detecting the current to obtain a coordinate value. 2. The coordinate detecting device according to claim 1, wherein the voltage value of the first reference voltage is larger than the voltage value of the second reference voltage. 3. Each wiring of the first wiring group is connected to the first reference voltage via a resistor, and each wiring of the second wiring group is connected to the second reference voltage via a resistor. A current flows through the wirings of the wirings of the first wiring group and the wirings of the second wiring group that are connected to each other and are in a short-circuited state,
The coordinate detecting device according to claim 1, wherein the coordinate value is obtained based on a voltage appearing in the resistor connected to the wiring. 4. A wire among the wires of the first wire group is searched for a wire in which a current flows through the resistor connected to the wire and the voltage of the wire is different from the first reference voltage. At the same time, among the wirings of the second wiring group, a wiring that is connected to the wiring and the current flows through the resistor and has a voltage different from the second reference voltage is searched for to detect a short-circuited wiring. The coordinate detection device according to claim 3, wherein. 5. A third voltage which is a voltage between the first reference voltage and the second reference voltage and which is higher than an intermediate voltage between the first reference voltage and the second reference voltage. A fourth reference voltage, which is a voltage lower than an intermediate voltage between the first reference voltage and the second reference voltage, is provided, and the fourth reference voltage among the wirings of the first wiring group is provided. A wiring having a voltage lower than a voltage is searched, a wiring having a voltage higher than the fourth reference voltage is searched for among the wirings of the second wiring group, and a short-circuited wiring is detected. Item 3
Alternatively, the coordinate detection device according to item 4. 6. A first switch group for switching and connecting, for each wiring of the first wiring group, a voltage at one end of the resistor connected to the wiring to a negative input terminal of a first comparator, A second switch group for switching and connecting, for each wiring of the second wiring group, the voltage at one end of the resistor connected to the wiring to the positive input terminal of the second comparator; The third reference voltage is input to a positive input terminal, the fourth reference voltage is input to a negative input terminal of the second comparator, and the first and second switch groups are connected to a predetermined clock. Wiring provided with first and second control means for supplying a predetermined switching control signal so as to be sequentially closed in synchronism with the wiring, which are in a short-circuit state based on the output voltages of the first and second comparators and the clock. The coordinate detection device according to claim 5, wherein