JPH05143222A - Tablet position detecting method - Google Patents

Abstract

PURPOSE:To provide a method which can detect the position of a tablet at a high speed and with high accuracy. CONSTITUTION:An external resistance is put between the X axis electrodes set at both ends of an X axis resistance plate or between the Y axis electrodes set at both ends of a Y axis resistance plate. Then the tap terminals A-E are provided at the middle of the external resistance for partition of the outputs of the resistance plates. Then both ends of the external resistance and the tap terminals are connected to an A/D converter circuit via the changeover switches 63 and 64 which are selectively switched to each other. In such a constitution of a resistance pressure-sensitive type tablet, the position of a pressed point is approximately detected in a state where the reference signals are applied from both ends of the resistance and the resistance plate is not partitioned. Then a specific section is decided based on the data obtained under such conditions for acquisition of a desired section with changeover the terminals A-E. Thus the position data is obtained with high accuracy in a selected section. Then the switches 63 and 64 are switched toward a Y contact while a prescribed point is pressed with a pen 17. Then the position information on the Y axis is obtained in the same way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of detecting a position of a resistance pressure-sensitive tablet capable of obtaining a capacity higher than the resolution of an A / D conversion circuit for speedy and highly accurate position detection. It is about.

[0002]

2. Description of the Related Art Generally, a resistance pressure-sensitive tablet is shown in FIG.
And as shown in FIG. 7, the X-axis electrodes 1 are provided on both ends in the X-axis direction.
The X-axis resistance plate 12 having 1 and 11 and the Y-axis resistance plate 14 having Y-axis electrodes 13 and 13 at both ends in the Y-axis direction are opposed to each other, and a gap is formed by the dot spacers 15 except for the upper surface. It is surrounded by a housing.

In order to obtain the position information of the X-axis resistance plate 12, first, the changeover switch 16 is changed over to the X contacts X ₁ , X ₂ and X ₃ side, and the predetermined point P is pushed by the pen 17 to press the both resistances. Board 1
Short circuit 2 and 14. Contact resistance 22 between the resistance plate and the conductor,
Assuming that the resistance values of 23 and the conductor resistances 26 and 27 are x ₃ , x ₄ , x ₅ and x ₆ , respectively, the voltage divided at the point P is obtained. Passes through the y ₂ side of the Y-axis resistance plate 14 and becomes A / as the X-axis position information.
It is input to the D conversion circuit 20. The reference voltage set by the resistor 19 is also input to the A / D conversion circuit 20. These data are converted into digital values and further processed by the arithmetic circuit 3
Then, the calculation is performed by the equation (1) and output to the output terminal 21 as X-axis position information.

Next, the changeover switch 16 is changed over to the Y contacts Y ₁ , Y ₂ , Y ₃ side while the point P is being pressed by the pen 17. Then, similarly, the divided voltage of the Y-axis Is input to the A / D conversion circuit 20 via the x ₂ side of the X-axis resistance plate 12. The reference voltage set by the resistor 19 is also input to the A / D conversion circuit 20 in the same manner as described above, converted into a digital value, and further sent to the arithmetic circuit 32 to perform the operation of the equation (2) to perform the Y-axis position. The information is output to the output terminal 21.

The applicant of the present invention has developed a resistance pressure-sensitive tablet as shown in FIG. 6 in which contact resistances 22, 23, 24, 25 are used.
Since the resistance values of the conductor resistances 26, 27, 28 and 29 are different for each tablet and there is a problem that the adjustment work is extremely troublesome, the improved one shown in FIG. 5 was proposed. This is the X-axis resistance plate 12 and the Y-axis resistance plate 14.
The X-axis auxiliary electrodes 30, 30 and the Y-axis auxiliary electrodes 31, 31 are provided slightly inside the X-axis electrodes 11, 11, Y-axis electrodes 13, 13 at both ends of the upper surface including the upper portions of these auxiliary electrodes. It is one that is surrounded by a housing except for.

The accuracy of the position information in the above device is set depending on which point the data between the auxiliary electrodes 30 and 30 and between the electrodes 31 and 31 corresponds to, for example, 256 equal parts in the A / D conversion circuit 20. Was there. Therefore, A / D
In order to improve the accuracy of the conversion circuit 20, the A / D conversion circuit 20 had to be finely divided into a more complicated circuit configuration.

The applicant of the present invention has already proposed the A / D conversion circuit shown in FIG. 3 and FIG. 4 as the one having further accuracy improved by providing the division electrode on the resistance plate even if the accuracy is the same as before. Proposed (Japanese Patent Application No. 2-331339).
Among them, the one shown in FIG. 3 is characterized in that the X-axis resistance plate 12 and the Y-axis resistance plate 14 are divided into two by the division electrode 61. As shown in FIG. 6, when there are only electrodes 11, 11, 13, 13 at both ends, these electrodes are divided into two by a dividing electrode 61 parallel to them, and
As shown in FIG. 5, when the X-axis auxiliary electrodes 30 and 30 and the Y-axis auxiliary electrodes 31 and 31 are provided slightly inside the electrodes 11, 11, 13, and 13 at both ends, respectively, the space between these auxiliary electrodes is set. It divides with the division electrode 61. Although FIG. 3 describes the X-axis resistance plate 12, the Y-axis resistance plate 14 can be similarly divided as necessary, and therefore is not shown.

The dividing electrode 61 divides the resistance plate 12 into two sections, a first section 12 ₁ and a second section 12 ₂ , and the + side auxiliary electrode 30 is connected to the contact a of the first changeover switch 63. The partition electrode 61 is connected to the contact b of the first changeover switch 63 and the contact a of the second changeover switch 64, and the auxiliary electrode 3 on the negative side is connected.
0 is coupled to the contact b of the second changeover switch 64, and the common contact of these first and second changeover switches 63 and 64 is A /
It is connected to the + input side R + and the-input side R- of the D conversion circuit 20, and the position output of the pen 17 is connected to the intermediate AD between them. The terminals of the data output D and the overflow output OF of the A / D conversion circuit 20 are coupled to the CPU 62, and the C
The PU 62 has an overflow output OF, and the first and second
Data is output while the changeover switches 63 and 64 are changed over.

In the structure described above, the voltage of the divided X-axis resistance plate 12 when the pin 17 presses the predetermined point P is y ₂ of the Y-axis resistance plate 14 and A via the Y-axis auxiliary electrode 31. /
It is sent to the D conversion circuit 20. Here, as shown in FIG. 3, it is assumed that the first and second changeover switches 63, 64 are changed over to the contacts a, a on the first section 12 ₁ side, and the pen 1
7 assuming that presses the P point of the second section 12 _2, + and the voltage of the auxiliary electrode 30, the voltage of the segment electrode 61 is sent to the A / D conversion circuit 20 as the reference voltage.
These are higher than the voltage at point P and are out of range, so
An overflow output OF appears, and a switching signal is output from the CPU 62 to switch the contacts b, b on the second section 12 ₂ side. Then, the output at point P falls within the range of the voltage between the segment electrode 61 and the auxiliary electrode 30, and the position data is output. Although not shown, position data is output in the same manner for the Y-axis resistance plate 14.

Next, in the example of FIG. 4, two section electrodes 6
An example is shown in which the numbers ₁ and 61 are divided into three parts 12 ₁ , 12 ₂ and 12 ₃ . In this case, the first and second changeover switches 63,
The 64 may be arranged so that the first section contacts a, a, the second section contacts b, b, and the third section contacts c, c are sequentially switched, and the operation is the same as described above.

The configuration shown in FIGS. 3 and 4 is characterized in that the X-axis resistance plate 12 and the Y-axis resistance plate 14 are divided into two or more by the division electrode 61, but the division electrodes are switched. The switch must be connected with leads to form a circuit. In particular, when the number of division electrodes increases, a large number of lead wires are drawn from the X-axis resistance plate 12 and the Y-axis resistance plate 14, so that the circuit configuration becomes complicated, and the contact resistance and conductor resistance of the lead wires are different. However, there is a problem that adjustment is extremely troublesome because it requires correction for each section. Therefore, the applicant of the present invention has simultaneously proposed, as shown in FIG. 2, a device in which an external resistor is inserted between the auxiliary electrodes at both ends and a tap terminal is provided in the middle of this resistor.

First, the case of the X-axis resistance plate 12 will be described in more detail. The X-axis resistance plate 12 has X on both ends.
The shaft electrodes 11 and 11 are formed, and further slightly inside thereof,
The X-axis auxiliary electrodes 30, 30 are formed. A resistor 47 is inserted between the X-axis auxiliary electrodes 30 and 30 via buffer circuits 45 and 46. The resistor 47 is divided into six points at points A and E slightly inward from both ends and points B, C and D in the middle to form resistors 48, 49 ₁ , 49 ₂ , 49 ₃ , 49 ₄ and 50. Of these points, the point A is connected to the contact a of the first changeover switch 63, the point B is connected to the contact b of the first changeover switch 63 and the contact a of the second changeover switch 64,
The points C and D are similarly connected, the point E is connected to the contact d of the second changeover switch 64, and the common contact of these first and second changeover switches 63 and 64 is connected to the buffer circuit 5.
+ Input side (R +) of the A / D conversion circuit 20 via 1, 52
And-the input side (R-), and the position output of the pen 17 is connected to the terminal AD. The terminals of the data output D and the overflow output OF of the A / D conversion circuit 20 are coupled to the CPU 62. The CPU 62 outputs the data while switching the overflow output OF with the first and second changeover switches 63 and 64.

In this way, the resistor 47 is connected to the resistors 48, 4
9 _1, 49 _2, 49 _3, 49 _4, 50 of the divided point a ratio A,
The X-axis auxiliary electrodes 30 and 30 of the X-axis resistance plate 12 are divided at the same ratio as B, C, D, and E, and the points are a, b, c, d, and e. Then, the resistance plate 12 is divided into the first, second, third and fourth sections 12 ₁ , 12 ₂ , 12 ₃ , 12 _4.
It is divided into four.

Next, assuming that the pin 17 presses the predetermined point P, for example, the fourth section 12 ₄ in the above-mentioned configuration, the divided voltage of the X-axis resistance plate 12 at that time is the Y-axis. A / D via the y _{2 of the} resistance plate 14 and the Y-axis auxiliary electrode 31.
It is sent to the conversion circuit 20. Here, as shown in FIG. 1, the first and second changeover switches 63 and 64 are set to the first section 12 first.
_It is switched to the contacts a, a on the _first side, and the voltage at the point A and the voltage at the point B are sent to the A / D conversion circuit 20 as reference voltages. Since these are higher than the voltage at the point P and are out of the range, the overflow output OF appears and the CPU 6
A switching signal is output from _{2 and} the contact b on the second section 12 ₂ side,
Switched to side b. Similarly, with four switching operations,
The output at point P is within the voltage range between points D and E, and the position data is output. Although not shown, the Y-axis resistance plate 14
Similarly, the position data is output.

[0015]

In the position detecting method as described above, if the number of divisions is n, it is necessary to perform a switching operation up to n times. Particularly, if the number of divisions is increased to improve the accuracy, the number of positions is increased. There is a problem that the detection takes time and the response speed becomes slow.

It is an object of the present invention to provide a tablet position detecting method for prompt and highly accurate position detection.

[0017]

An external resistance is inserted between at least one of the X-axis electrodes at both ends of the X-axis resistance plate and at least between the Y-axis electrodes at both ends of the Y-axis resistance plate. A resistance pressure-sensitive type in which tap terminals for dividing the output of the resistance plate are provided on the way, and both ends of the resistance and the tap terminals are coupled to an A / D conversion circuit through a changeover switch for selectively switching When detecting a position in a tablet, firstly, a reference signal is applied from both ends of the resistor to detect the approximate position of the pressing point in a state where the resistance plate is not divided. It is a tablet position detecting method characterized in that the position of the tablet is detected by switching the tap terminals so as to obtain a high-accuracy position data so as to obtain a target section.

[0018]

In order to obtain the position information of the X-axis resistance plate, first, the changeover switch is switched to the X contact side, and a predetermined point is pressed by the pen to short-circuit both the X-axis resistance plate and the Y-axis resistance plate. So, first
In addition, the reference signal is applied from both ends of the resistor to detect the approximate position of the pressing point in a state where the resistance plate is not divided, and then the data at this time is used to determine which division is the target division. As described above, the tap terminals are switched to obtain highly accurate position data in the selected section. Next, the Y-axis position information is obtained in the same manner by switching the changeover switch to the Y contact side while the predetermined point is being pressed by the pen.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. 1 has a configuration similar to that of FIG. 2 described above, but in the present invention, the function of the CPU 62 is particularly different. That is,
When detecting the position, the CPU 62 firstly determines that the X-axis resistance plate 12 is not divided and the pin 1
The approximate position when the predetermined point P is pressed at 7 is detected.
Based on the data at this time, the CPU 62 determines which section is selected and controls the first and second changeover switches 63 and 64 so that the target section is selected. Get the data.

More specifically, the first and second changeover switches 63 and 64 are initially changed over to the contacts a and d regardless of the division. Here, when the pen 17 is assumed to be pressing the P point of the fourth segment 12 _4, and the voltage at point A, with the voltage at point E is fed to the A / D converting circuit 20 as the reference voltage, P The voltage at the point is sent to the A / D conversion circuit 20. Based on these data, it is detected that the position of the point P is in an approximate position, for example, the fourth section 12 ₄ . Based on these position data, the CPU 62 causes the first and second changeover switches 63, 6
A signal for switching the contacts of 4 to d, d is output. Then, the output at point P falls within the voltage range between points D and E, and highly accurate position data is output. Although not shown, position data is output in the same manner for the Y-axis resistance plate 14.

FIG. 1 shows an example in which the resistance plate 12 is divided into four, but the number of divisions is not limited to the above example. Further, the number of sections of the X-axis resistance plate 12 and the Y-axis resistance plate 14 need not be the same.

In the example of FIG. 1, the contact resistance 2 is the same as in FIG.
2, 23, 24, 25 and conductor resistances 26, 27, 28, 2
The resistance value of 9 is different for each tablet, and the adjustment work is very troublesome, and this is improved by providing the X-axis auxiliary electrodes 30, 30 and the Y-axis auxiliary electrodes 31, 31 respectively. The case where it was applied to the above was explained. However, the present invention is not limited to this case, and as shown in FIG. 6, the X-axis auxiliary electrodes 30 and 30 and the Y-axis auxiliary electrode 3 are provided.
The present invention can be applied even if it does not have 1, 31.

[0023]

As described above, according to the present invention, in order to obtain the position information of the X-axis resistance plate, first, the changeover switch is changed over to the X contact side, and the pen is pressed to a predetermined point to press the X axis and the Y axis. Short circuit between both resistance plates. Therefore, first of all, the reference signal is applied from both ends of the resistor to detect the approximate position of the pressing point in a state where the resistance plate is not divided, and then the data at this time is used to determine which division. The tap terminals were switched to obtain the target division, and highly accurate position data was obtained in the selected division. Therefore, the target position information can be detected promptly and with high accuracy. In addition, the circuit configuration becomes simple,
This has the effect that adjustment is unnecessary.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a tablet position detecting method according to the present invention.

FIG. 2 is a circuit diagram showing a resistance pressure-sensitive tablet proposed by the present applicant.

FIG. 3 is a circuit diagram of a resistance pressure sensitive tablet previously proposed by the present applicant.

FIG. 4 is a circuit diagram of a resistance pressure sensitive tablet previously proposed by the present applicant.

FIG. 5 is a circuit diagram of a conventional resistance pressure-sensitive tablet.

FIG. 6 is a circuit diagram of a conventional resistance pressure-sensitive tablet.

FIG. 7 is a cross-sectional view of a conventional resistance pressure-sensitive tablet.

[Explanation of symbols]

11 ... X-axis electrode, 12 ... X-axis resistance plate, 13 ... Y-axis electrode,
14 ... Y-axis resistance plate, 15 ... Dot spacer, 16 ... Changeover switch, 17 ... Pen, 19 ... Resistor, 20 ... A / D conversion circuit, 21 ... Output terminal, 22, 23, 24, 25 ... Contact resistance, 26 , 27, 28, 29 ... Conductor resistance, 30 ... X
Axis auxiliary electrode, 31 ... Y-axis auxiliary electrode, 32 ... Arithmetic circuit, 3
3, 34, 35, 36 ... Contact resistance, 37, 38, 39,
40 ... Conductor resistance, 45, 46 ... Buffer circuit, 47, 4
8, 49 ₁ , 49 ₂ , 49 ₃ , 49 ₄ , 50 ... Resistance, 51,
52 ... Buffer circuit, 61 ... Sorting electrode, 62 ... CPU,
63, 64 ... Changeover switch, A, B, C, D, E ... Tap terminals.

Claims (2)

[Claims] 1. An external resistance is inserted between at least one of the X-axis electrodes at both ends of the X-axis resistance plate and at least between the Y-axis electrodes at both ends of the Y-axis resistance plate. A resistance pressure-sensitive tablet is provided in which a tap terminal for dividing the output of the resistance plate is provided, and both ends of the resistance and the tap terminal are connected to an A / D conversion circuit through a changeover switch that selectively changes the position. At the time of detection, firstly, a reference signal is applied from both ends of the resistor to detect the approximate position of the pressing point in a state where the resistance plate is not divided, and then the division at this time is determined by the data at this time. A position detecting method for a tablet, characterized in that the tap terminals are switched to obtain a desired division, and highly accurate position data is obtained in the selected division. 2. An X-axis auxiliary electrode and a Y-axis auxiliary electrode are provided between the X-axis electrodes at both ends of the X-axis resistance plate and inside the Y-axis electrodes at both ends of the Y-axis resistance plate, respectively, and the X-axis auxiliary electrodes at both ends are provided. An external resistance is inserted between the auxiliary electrodes and at least one of the Y-axis auxiliary electrodes at both ends, and a tap terminal for dividing the output of the resistance plate is provided in the middle of this external resistance. In a resistance pressure-sensitive tablet in which both ends and tap terminals are coupled to an A / D conversion circuit via a change-over switch that selectively changes, first of all, when detecting a position, firstly apply a reference signal from both ends of the resistor. The approximate position of the pressing point is detected without dividing the resistance plate with the resistor plate, and then the tap terminal is switched and selected so that it is the target segment by judging which segment it is based on the data at this time. High accuracy in classification Position detection method of the tablet, characterized in that to obtain the data.