JPS62117025A - Coordinate detector - Google Patents

Abstract

PURPOSE:To improve the coordinate detecting accuracy by attaining such a fact that the detecting accuracy for the coordinates of a contact point is dependent only on the ununiformity of a resistance film between two linear electrodes and no detection error is produced among other linear electrodes. CONSTITUTION:The resistance value between two adjacent linear electrodes is set at the same level by the 2nd resistor group 4 among those linear electrodes 2a-2h formed on the 2nd resistance plate 2. In other words, the variance of the resistance value due to the ununiformity of the resistance films formed between adjacent linear electrodes 2a-2b-2f-2g respectively is corrected by the resistances 4a-4g (the 2nd resistor group 4) which are put between two adjacent linear electrodes. Thus, the resistance value is equal among those electrodes 2a-2b-2f-2g respectively. Therefore, no detection error of coordinates is produced among electrodes 2a-2c and 2d-2h respectively as long as a pressed area 9 is positioned between both linear electrodes 2c and 2d. As a result, the detection error of coordinates is dependent only on the ununiformity of the resistance value 10 of the resistance film formed between the electrodes 2c and 2d.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coordinate detection device, and in particular, a coordinate detection device that detects the position of characters, figures, etc. drawn on a tablet input panel, etc., and outputs it to another display device, etc. The present invention relates to a coordinate detection device.

(Prior Art and Problems to be Solved by the Invention) Conventionally, most coordinate detection devices of this type have adopted a surface electrode sheet method or a digital method.

FIG. 4 is a configuration diagram showing the main parts of a conventional plane electrode resistive sheet type coordinate detection device, in which 13 is a constant current power supply, 15 is a first resistive plate, and 16 is a second resistive plate.

The first resistance plate 15 has flexibility, and has first resistor plates at both ends thereof.
electrodes 15a and 15b are provided in parallel. Further, the second resistance plate 16 also has flexibility, and a second electric current f1! is provided at both ends thereof so as to be orthogonal to the first electrode. ! l1
6a and 16b are provided in parallel.

A resistive film is applied to each of the first resistive plate 15 and the second resistive plate 16, and there is a gap between the first resistive plate 15 and the second resistive plate 16. It is provided.

By pressing one point on the first resistance plate 15, the first resistance plate 15 and the second resistance plate 16 are brought into contact with the pressed position. Due to this pressing point, the current flowing from the constant current source 13 is transferred to the first detection resistors 14a, 14 which are electrically connected to the first electrode.
b and the first electrodes 15a, 15b, flows into the first resistance plate 15, and flows into the second resistance plate 16 through the press location. Furthermore, the current flows through the second electrode 16
a.

16b and is grounded through second detection resistors 17a and 17b that are electrically coupled to the second electrode. Furthermore, current detectors 18 and 20 are connected to both ends of the first detection resistor 14b and the second detection resistor 17b, respectively.
are combined.

This conventional example has a current ib flowing through the first detection resistor 14b and a current id flowing through the second detection resistor 17b.
is measured by the current detectors 18 and 20, and the coordinates of the pressed location are detected.

Here, the second electrode 16a is detected using the currents ic and id flowing through the second detection resistors 17a and 17b.

16b, the coordinates of the pressed point in the direction (X direction) perpendicular to 16b are expressed as id/(ic + id
) will be proportional to And the current (ic + i
d) is supplied from the constant current power supply 13, so the second
The current id flowing through the detection resistor 17b is detected by the current detector 2.
By measuring at 0, the coordinate in the X direction will be detected. Similarly, in the Y direction, the current ib flowing through the first detection resistor 14b is detected by the current detector 18.
By measuring with , the coordinate in the Y direction is detected. Here, the output terminals 19 and 21 of the current detectors 18 and 20 output the detected current values in the Y direction and the X direction of the pressed location.

However, in the surface electrode sheet type coordinate detection device described above, the detected position accuracy is limited to the first resistor plate 1.
5 and the uniformity of the resistive film coated on the second resistive plate 16, it has been difficult to detect coordinates with high accuracy using the coordinate detecting device.

FIG. 5 is a configuration diagram showing the main parts of a conventional digital coordinate detection device, in which 22 is a first sheet, 23 is a second sheet, 24 is a first switch means, and 25 is a second switch. It is a means.

The first sheet 22 is made of an insulating material, and a plurality of parallel first line electrodes are formed on its surface. Further, the second sheet 23 is also made of an insulating material, and on its surface,
A plurality of parallel second line electrodes are formed perpendicularly to the first line electrode. The first line electrode and the second line electrode are in contact with each other at the pressed location. The first line electrodes are connected to first switch means 24 controlled by a control circuit 27, and each line electrode is sequentially selected and coupled by the first switch means 24. Further, the second line electrode is a second wire electrode.
The second switch means 25 is coupled to the same 3% 31 circuit 28.

Then, the signal from the power source 26 reaches the first line electrode formed on the first sheet 22 via the first switch means 24. Therefore, when the first sheet 22 is pressed, the first sheet 22 and the second sheet 2
3 is in contact, and the signal from the power source 26 reaches the second line electrode via this pressed point. Then, it is detected by the second switch means 25, and the detected signal is synchronized with the control position signal of the control circuit 27 by the synchronization circuit 28, and the position information of the contact portion is output from the output end 29. That will happen.

However, this digital coordinate detection device not only has a complicated circuit, but also requires an increase in the number of line electrodes formed on each sheet in order to improve detection accuracy. had its limits.

[Means and effects for solving the problems] The present invention has been made in view of the above-mentioned problems, and provides a novel coordinate detection device, in which a plurality of parallel wire electrodes are connected to each other with resistance. a first resistance plate formed at equal intervals on the film;
a second resistance plate in which a plurality of parallel line electrodes perpendicular to the plurality of line electrodes on the first resistance plate are formed at equal intervals on the resistance film; A first resistor group in which a resistor is inserted between two adjacent wire electrodes, and a first resistor group in which a resistor is inserted between two adjacent wire electrodes, and two adjacent wire electrodes of a plurality of wire electrodes formed on the second resistance plate. a second resistor group with a resistor inserted between each, a power source, switching the applied voltage from the power source to the first resistor group and the second resistor group, and pressing the resistor plate. a switch means that switches the detected signal output according to the location so that it can be extracted as a potential;
The first resistor group and the second resistor group cause the resistive films of the first resistive plate and the second resistive plate to have substantially uniform resistance values, and the pressing point is It is designed to find the potential of .

〔Example〕

Embodiments of the coordinate detection device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing the main parts of an embodiment of the coordinate detection device according to the present invention, where ■ is a first resistance plate, 2 is a second resistance plate, 3 is a first resistor group, 4 is a second resistor group, 5 is a power supply, and 6 is a switch means.

A resistive film is coated on the first resistive plate l, and the resistive film has a plurality of parallel line electrodes 1a, lb, lc,
ld.

le and IF are formed at equal intervals. Similarly, a resistive film is applied to the second resistive plate 2, and the resistive film has a plurality of parallel line electrodes 2a, 2b, 2c, 2d.
, 2e, 2f.

2g and 2h are formed at equal intervals. The wire electrode 2
A to 2h are arranged to be orthogonal to the line electrode 1a=1F. Resistances 3a, 3b, 3c, 3d,
3e are respectively provided to constitute the first resistor group 3. Similarly, there are resistors 4a, 4b, 4c, 4d between two adjacent line electrodes of the line electrodes 2a to 2h.
, 4e, 4f, and 4g are provided to constitute the second resistor group 4. These first resistor group 3 and second resistor group 4 each have a resistance inserted in parallel between two adjacent line electrodes, and the first resistance Both ends of the resistor group 3 and the second resistor group 4 are connected to the switch means 6, respectively. The switch means 6 switches the applied voltage from the power source 5 to the first resistor group 3 and the second resistor group 4, and switches and couples the detected voltage signal to the voltage amplifier 7. It is for.

As shown in FIG. 1, each switch 6a, 6b, and 6C of the switch means 6 connects one end of the second resistor group 4, one end of the first resistor group 3, and the first resistor group 3, respectively. The voltage of the power supply 5 is applied to the first resistor group 3, and one end of the second resistor group 4 is coupled to the voltage amplifier 7. , the position of the pressed contact point on the first resistance plate 1 (in the Y direction) connects the second resistance plate 2 and the second resistance plate 2 through the contact point.
It passes through one end of the resistor group 4 and is detected as a potential signal.

This detected potential signal reaches the voltage amplifier 7 via the switch 6a, and the coordinate signal is taken out from the output terminal 8.

The position of the contact point on the second resistance plate 2 (in the X direction) is determined by switching the switch means 6 and each switch 6.
a, 6b and 6c are respectively one end of the first resistor group 3, one end of the second resistor group 4, and the second resistor group 3.
The voltage of the power supply 5 is applied to the second resistor group 4, and one end of the first resistor group 3 is coupled to the voltage amplifier 7. through the contact point when
It passes through one end of the first resistor plate 1 and the first resistor group 3 and is detected as a potential signal.

Here, the voltage amplification device 7 needs to have high human impedance, but depending on the signal, the amplification means may be unnecessary. Furthermore, the polarity of the power source 5 is inverted, and the output signal of the output terminal 8 is A/(A+B).
(Here, A and B are output values due to polarity reversal.) By a1 calculation, the first resistance plate l or the second JIE
It is also possible to calculate the position of the contact point on the resistor 41i 2.

FIG. 2 is a partially enlarged view of FIG. 1, showing wire electrodes 2c and 2d formed on the second resistance plate 2 and a resistor 4C provided between these two wire electrodes. . Here, 9 equivalently represents the pressing location and 10 equivalently represents the resistance of the resistive film between the wire electrodes 2C and 2d.

The coordinate detection accuracy of this embodiment will be explained with respect to the second resistor plate 2 and the second resistor group 4.

The wire electrodes 28 to 2h formed on the second resistive plate 2 are made so that the resistance values between two adjacent wire electrodes are all made the same by the second resistor group 4. That is, two adjacent line electrodes 2a-2b.

2b-2c, 2cm2d, 2d-2e, 2
The variation in resistance value between e-2f and 2f-2g due to the non-uniformity of the resistive film is caused by the resistance value inserted between the respective two adjacent line electrodes 4a and 4.
b, 4c, 4d, 4e, 4f.

4g (second resistor group 4), and the resistance values between the two adjacent wire electrodes are all the same. Therefore, when the pressing point 9 is between the two adjacent wire electrodes 2C and 2d as shown in FIG. 2, between the wire types 142a to 2c and 2d to 2h,
As described above, since the resistance values between the two adjacent wire electrodes are all the same, no coordinate detection error occurs. Therefore, the detection error of such coordinates depends only on the non-uniformity of the resistance value 10 of the resistive film between the two wire electrodes 2c and 2d, and the detection error of the coordinates is greatly reduced. can be done.

Also, here, as the second resistor group 4, a resistor 48 to 4g inserted between each adjacent two wire electrodes is used.
may have the same resistance value, and the resistance value may be so small that non-uniformity of the resistance film between two adjacent line electrodes can be ignored. In this case, although the resistance values between the two adjacent wire electrodes are not strictly the same, there is no need to make the resistances 48 to 4g of the second resistor group 4 different, and they are the same. A resistance value can be used. However, the resistance value of these resistors 48~4g is the resistance value of the resistive film between each two adjacent wire electrodes! (It is necessary to set a resistance value that is smaller than the resistance value and allows a large current to flow so that the current flowing through the resistive film between the wire electrodes can be ignored.

Although the above description has been made regarding the second resistor plate 2 and the second resistor group 4, the same applies to the first resistor plate 1 and the first resistor group 3.

FIG. 3 is a graph showing the relationship between distance and voltage measured by the coordinate detection device shown in FIG. 1 and a conventional similar coordinate detection device; The curve 12 is a curve measured using a similar conventional coordinate detection device.

As is clear from FIG. 3, the curve 11 measured by the embodiment of the coordinate detection device according to the present invention sufficiently corrects the coordinate detection error due to the non-uniformity of the resistive film of the curve 12 of the conventional example. This shows that this example has high coordinate detection accuracy.

(Effects of the Invention) As described above in detail, the coordinate detection device according to the present invention has a precision in detecting the coordinates of a contact point due to the non-uniformity of the resistive film between the two wire electrodes including the contact point. Since the detection error does not occur between other line electrodes, the coordinate detection device according to the present invention has a simple configuration and can be provided at low cost. 9゜ possible

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the coordinate detection device according to the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 shows the coordinate detection device shown in FIG. A graph showing the relationship between distance and voltage measured by a similar coordinate detection device, Figure 4 is a configuration diagram showing the main parts of a conventional surface electrode resistance sheet type coordinate detection device, and Figure 5 is a diagram of a conventional digital type coordinate detection device. FIG. 2 is a configuration diagram showing main parts of a coordinate detection device. DESCRIPTION OF SYMBOLS 1... First resistance plate, 2... Second resistance plate, 3... First resistor group, 4... Second resistor group, 5... Power supply, 6. ... Switch means, 7... Voltage amplifier.

Claims (1)

[Claims] A first resistance plate having a plurality of parallel line electrodes formed on the resistance film at equal intervals, and a plurality of parallel line electrodes orthogonal to the plurality of line electrodes of the first resistance plate formed equally on the resistance film. a second resistor plate formed at intervals, and a first resistor group in which a resistor is inserted between each of two adjacent wire electrodes of the plurality of wire electrodes formed on the first resistor plate; , a second resistor group in which a resistor is inserted between two adjacent wire electrodes of the plurality of wire electrodes formed on the second resistor plate, a power source, and an applied voltage from the power source. A coordinate detection device comprising: a switch means that switches between the first resistor group and the second resistor group, and switches the detected signal output according to the pressed position of the resistor plate so that it can be taken out as a potential. .