JPH04162122A - Position detector - Google Patents

Abstract

PURPOSE:To decide the position of a designating point on a surface resistance sheet by selecting successively two or more dot electrodes among those dot electrodes provided on the resistance sheet and obtaining the distances between the selected dot electrodes and the pointed point. CONSTITUTION:A surface resistance sheet 1 comes into contact with a conductor sheet 4 at the position of a point P which is deformed with the pressure of a position pointing device 8. At this time, a switch 2a is turned on and a dot electrode D1 is connected to a power supply 3. Thus a potential difference VS is produced between both ends of a fixed resistance 6. The resistance value R1 produced between the electrode D1 and the point P pointed by the device 8 is uniquely obtained from the difference VS. On the other hand, the coordinates of the point P are uniquely decided on the sheet 1 as an intersecting point between two circles drawn around the dots D1 and D2. Thus the distances between the point and both dot electrodes D1 and D2 are obtained. Then the accurate position of the point P pointed by the device 8 can be detected.

Description

[Detailed description of the invention] [Industrial application field]

This invention provides an input device for OA equipment such as a computer.
The present invention relates to a position detection device.

[Conventional technology]

Conventionally, a certain point (position) in the input device of the above-mentioned OA equipment
As a position detection device used to input the coordinates of
There is something like the one shown in Figure 6. This position detection device is
Electrode BI connected to power source 35. B, a sheet resistance sheet 31 provided on both sides, and a conductive sheet 3 placed opposite to the sheet resistance sheet 31.
2, a plurality of spacers 33, 33 . - and a processing device 3 that processes signals from the conductive sheet 32 and the like.
It is roughly composed of 6. The position detection device having the above configuration operates as follows. First, the electrodes B provided on both sides of the sheet resistance sheet 31
A potential difference Vs is applied between + and B. At this time, assume that a gradient potential proportional to the position in the X direction in FIG. 6 appears on the sheet resistance sheet 31, as shown in FIG. 8, for example. In this state, when a point Q on the sheet resistance sheet 31 is pressed by the position indicator 34, the spacers 33, 33. As shown in FIG. 7(b), the sheet resistance sheet 3I and the conductor sheet 32, which were electrically separated by ..., are deformed at the position Q pressed by the position indicator 34. to make electrical contact with the conductive sheet 32. The conductive sheet 32 is connected to a processing device 36, or the input impedance of the processing device 36 is set to be sufficiently high. Therefore, the electric potential of the conductive note 32 becomes a value equal to the electric potential difference Vq at a point Q indicated by the position indicator 34 and located at X=XQ on the one-sided resistive sheet 31. Therefore, based on the value of the potential Vq at one point Q that is input to the processing device 36 via the conductor sheet 32, the potential difference is determined from the relationship between the position in the X direction and the potential difference as shown in FIG. The coordinates Xq in the X direction of the position indicated by the position indicator 34 can be determined from VQ. The position detecting device shown in FIG. 9 is an improved version of the position detecting device shown in FIG. That is, a plurality of electrodes B3 to Bn are arranged in parallel to the electrode B1°B between the electrodes B, , B provided on both sides of the sheet resistance sheet 31 in FIG. The sheet resistance sheet 31 is divided into several regions by ~Bn. Then, a potential difference is sequentially applied to the electrodes at both ends of each region, thereby increasing the gradient of the potential gradient within each region as shown in FIG.

[Problem to be solved by the invention]

However, each of the conventional position detection devices described above has the following problems. First, in the position detection device shown in FIG. 6, since the slope of the gradient potential on the sheet resistance sheet 31 is small as shown in FIG.
There is a problem that the distance at which two points can be identified in a direction cannot be set finely, and the resolution of position detection is low. In addition, in the position detection device shown in Fig. 9, the gradient potential within each region increases and the resolution of position detection increases, but when calculating the gradient potential within each region, all the multiple electrodes are operated. Therefore, there is a problem that the detection time becomes longer and the number of coordinates detected per unit time decreases. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a position detection device that can detect a designated coordinate position with high precision and efficiency.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a position detection device that detects a position on a sheet resistance sheet indicated by a position indicator, which includes a plurality of point electrodes provided on the sheet resistance sheet, and a plurality of point electrodes provided on the sheet resistance sheet; A conductor sheet arranged in parallel with the sheet opposite to each other via a spacer, a switching circuit for switching and selecting one of the plurality of point electrodes provided on the sheet resistance sheet, and a switching circuit for switching and selecting one of the plurality of point electrodes provided on the sheet resistance sheet; Two or more point electrodes provided on the sheet are sequentially selected one by one by the switching circuit, and the indicated point on the sheet resistance sheet indicated by pressing the position indicator comes into contact with the conductive sheet. Then, the resistance values between the two or more selected point electrodes and the indicated point on the upper surface resistance sheet are sequentially measured according to a predetermined procedure, and the distance between the point electrode and the indicated point is determined. and a position calculation unit that calculates the position of the indicated point indicated by the position indicator on the sheet resistance sheet based on the calculated distance between the two or more point electrodes and the indicated point. It is characterized by

[Operation] Two or more point electrodes among the plurality of point electrodes provided on the surface resistance sheet are sequentially selected one by one by the switching circuit, and the position indicated by the position indicator is pressed. A pointing point on the resistive sheet contacts the conductive sheet. Then, the position calculating section first measures the resistance value between the selected point electrode and the indicated point according to a predetermined procedure, and calculates the distance between the selected point electrode and the indicated point. Furthermore, in a similar manner, the resistance value between the next selected point electrode and the indicated point is measured according to a predetermined procedure, and the distance between the point electrode and the indicated point is calculated. In this way, by calculating the distances from two or more point electrodes on the sheet resistance sheet to the indicated point, the position of the pointed point on the sheet resistance sheet is determined.

【Example】

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments. FIG. 1 is a block diagram of a position detection device according to the present invention. A sheet resistance channel 1 with point electrodes or point electrodes provided on both adjacent corners, and a sheet resistance sheet 2 provided on the surface resistance sheet l.
A switching circuit 2 which switches and selects two point electrodes, ,D, by a switch, and a point electrode, ,D, of the sheet resistance sheet l.
A conductive sheet 4 and the two point electrodes placed side by side facing each other, D. A power supply 3 connected to one of them selected by the switching circuit 2 and the conductor track 4, and a sheet resistance sheet l.
A plurality of spacers 5, 5 are provided between the conductor sheet 4 and the conductive sheet 4 to keep them in an electrically non-contact state.
．． and a fixed resistor 6 interposed between the conductive sheet 4 and the power source 3 (of which two spacers 5, 5 are installed between the point electrode plate and the point electrode plate and the conductor roll 4), Measure the voltage Vs across the fixed resistor 6 and calculate the resistance between the indicated point P indicated by pressing the position indicator 8 and the point electrode D1 or point electrode 7 selected by the switching circuit 2,
It is generally composed of a processing circuit 7 that calculates the position on the sheet resistance sheet l indicated by the position indicator 8. The conductor sheet 4 is connected to the power source 3 via the fixed resistor 6, but no current is flowing through the conductor sheet 4.
The entire surface is uniformly at the power supply voltage Vi. The position detection device having the above configuration is operated as follows. As shown in FIG. 2(a) to FIG. 2(b), the unique P on the sheet resistance sheet l is suppressed by the position indicator 8. Then, spacer 5.5. The sheet resistance sheet I, which had been separated from the conductive sheet 4 due to the above, is deformed by the pressure of the position indicator 8 and comes into contact with the conductive note 4 at the position of the point P. At this time, for example, if the switch 2a is turned on and the point electrode is connected to the power source 3, and the point electrode is left in an electrically floating state, the power source 3 - the fixed resistor 6 →
Electricity flows in the order of the conductor sheet 4 - the contact point P between the conductor seal and the sheet resistance channel 1 - the point electrode, - the power supply 3, and a potential difference Vs is generated across the fixed resistor 6 . In this case, the relationship between the resistance value Rf of the fixed resistor 6, the resistance value R1 between the indicated point P and the point electrode D1, the power supply voltage Vi, and the voltage Vs across the fixed resistor 6 is expressed by the following equation. holds true. R, = ((Vi/Vs) -1) R1 Therefore, by measuring the voltage Vs across the fixed resistor 6, the resistance value R4 between the point P indicated by the position indicator 8 and the point electrode 3 can be uniquely determined. I understand that. Further, the relationship between the distance between two points on the sheet resistance sheet 1 and the resistance value can be expressed by an appropriate function. Therefore, first, switch 2a in switching circuit 2 is
"on" and the point P indicated by the position indicator 8 and the point electrode D1
A resistance value R1 between the two is determined by the processing circuit 7. Furthermore, the distance between the designated point P and the point electrode D1 is calculated based on this resistance value R1. Next, the switch 2b in the switching circuit 2 is turned on, and the point P indicated by the position indicator 8 is turned on.
The resistance value R7 between the point electrode Dt and the point electrode Dt is determined. Furthermore, the distance between the indicated point P and the point electrode D1 is determined based on this resistance value R1. Calculate. On the other hand, the coordinates of the indicated point P on the sheet resistance sheet l are uniquely determined as the intersection of a circle with a radius L1 centered on the point electrode D1 and a circle with a radius L1 centered on the point electrode D1. In this way, by determining the distances from the two point electrodes, , D, to the indicated point P, the position of the indicated point P on the sheet resistance sheet 1 can be specified. 1. Then, as described above, the pointing point P and the pixel electrode, ,D,
By determining the distance, , L, between , the position of the point P indicated by the position indicator 8 on the sheet resistance sheet l can be accurately detected. That is, the processing circuit 7 constitutes the position calculation section. In the next embodiment, which is different from the above embodiment, the position of the pointing point is detected with even higher accuracy by applying the above embodiment. In FIG. 3, this position detection device includes a plurality of point electrodes D
1. -A sheet resistance sheet 11 in which Dmn is provided in the form of lattice points
and a point electrode D+1 provided on this sheet resistance sheet 11.
Switching circuit for switching and selecting ~D+++n 12.12.
. . . , the conductor sheet 14 placed opposite to the point electrodes DIl to Dmn side of the sheet resistance sheet 11, and the switching circuit 12.1 among the plurality of point electrodes D++-Dmn.
2. between the power supply 13 connected to one point electrode selected by . Measure the fixed resistor 16 interposed between the conductor sheet 14 and the power source 13, and the voltage Vs across the fixed resistor 16, with the spacer +5°15, -, which is interposed to keep them in an electrically non-contact state. Then, the resistance between the point Q indicated by pressing the position indicator 18 and the point electrode selected by the switching circuit 12 is calculated, and the position on the sheet resistance sheet 1 indicated by the position indicator 18 is calculated. It is generally composed of a processing circuit 17 that calculates . The position detecting device having the above configuration is operated through two steps described below. First, in the first step, as shown in FIG. 4, point electrodes D11 and point electrodes provided at both adjacent corners,
n to switching circuits 12, 12 . The point electrodes D are selected one by one one by one based on the voltage Vs across the fixed resistor 16 determined by the processing circuit 17 in FIG.
11 and the indicated point Q indicated by the position indicator 18 and the resistance value between n and the indicated point Q are sequentially determined. Then, based on the above two resistance values, the distance of the indicated point Q from the point electrode D I+ and the point electrode N is determined, and the approximate position of the indicated point Q is determined. Next, in the second step, the exact position of the indicated point Q whose approximate position was determined in the first step is determined. That is, a plurality of point electrodes (for example, three points D(k, Q), D(k, Q+1), and D(k+1.Q) near the approximate position of the indicated point Q obtained in the first step above are Point electrodes D (k, 1
2) Calculate the distances between D (k. C+1), D (lt+1.12) and the indicated point Q. Then, based on the above-mentioned three distances regarding the obtained indicated point Q, three positions of the indicated point Q on the sheet resistance sheet 11 are calculated. By averaging the positions of the indicated point Q obtained in three ways in this way, the position of the indicated point Q on the surface resistance sheet 11 indicated by the position indicator 18 is determined more accurately. That is, in this embodiment, in the first step, the fourth
As shown in the figure, the approximate position of the indicated point Q is determined based on two point electrodes D + + and D 1 n selected at a distance from among the point electrodes provided in the form of lattice points on the sheet resistance sheet 11. seek. After doing so, in the second step,
As shown in FIG. 4, the position of the indicated point Q on the sheet resistance sheet 11 is calculated multiple times based on a plurality of point electrodes close to the approximate position of the indicated point Q, and the average value is used to calculate the accuracy of the indicated point Q. The purpose is to find a suitable position. In the above-mentioned position detection device having a plurality of point electrodes, when the position of the indicated point Q indicated on the sheet resistance sheet ll by the position indicator 18 is continuously detected in time series at predetermined time intervals, Do as follows. That is, based on the change in the position vector of the indicated point Q based on the position of the indicated point Q detected several times in succession, it is used in the second step when detecting the position of the next indicated point Q. It predicts the three optimal point electrodes. Then, using these three predicted point electrodes, the next instruction point Q
The position of the robot is detected. By doing this, 1
Although it is necessary to perform the above-described first step when detecting the position of the indicated point Q for the second time, the first step can be omitted when detecting the position of the indicated point Q for the second and subsequent times. As a result, it is possible to increase the detection speed during continuous position detection. In the second step in the above embodiment, three point electrodes are set near the approximate positions determined on the sheet resistance sheet 11 in the first step, but the number is not limited to this. The switching circuit 2.12 in the above embodiment is the sheet resistance sheet 1
．． It may be constructed with a large number of switches for turning on and off electricity to each electrode provided on the electrode 11, or it can be easily constructed using a multiplexer or the like. In the above embodiment, the resistance value between the point electrode and the indicated point is obtained by measuring the voltage across the fixed resistor 7.17, but other methods are used to obtain the resistance value between the point electrode and the indicated point. It is also possible to obtain a resistance value between .

【Effect of the invention】

As is clear from the above, the position detection device of the present invention is
A plurality of point electrodes are provided on the sheet resistance sheet, and two or more point electrodes are sequentially selected one by one from the plurality of point electrodes by a switching circuit. Then, the position calculation unit calculates the distance between one point electrode that is sequentially selected and the point indicated by the position indicator according to a predetermined procedure based on the resistance value therebetween. As a result, the distance between two or more point electrodes and the indicated point is determined, and the position of the indicated point on the sheet resistance sheet can be determined based on the determined distance. Therefore, the position on the sheet resistance sheet indicated by the position indicator can be detected with high precision and efficiency, regardless of the position detection resolution based on the gradient potential formed on the sheet resistance sheet.

[Brief explanation of drawings]

Figure 1 is a block diagram of an embodiment of the position detection device of the present invention, and Figure 2 is a diagram showing the configuration of an embodiment of the sheet resistance sheet in Figure 1. 3 is a configuration diagram of a position detection device in an embodiment different from that in FIG. 1, and FIG. 4 is an example of selection of point electrodes during the second step by the position detection device of FIG. 3. FIG. 5 is a sectional view of the sheet resistance sheet and conductor sheet in FIG. 3, FIG. 6 is a configuration diagram of a conventional position detection device, and FIG. 7 is a cross-sectional view of the sheet resistance sheet and conductor sheet in FIG. 6. Sectional view of the sheet, No. 8
The figure shows the gradient potential between the electrodes in Fig. 6, Fig. 9 shows a sheet resistance sheet in a conventional example different from Fig. 6, and Fig. 1O shows each electrode in the sheet resistance sheet shown in Fig. 9. FIG. 1.11... Surface resistance sheet, 2.12 - Switching circuit, 3.13... Power supply, 4
．． 14...Conductor sheet, 5.15...Spacer, 6.16...Fixed resistor, 7,17...Processing device, 8.1...Position indicator, D+ ~ D! , Dll ~Dmn=-1 [pol. Figure 1 Figure 2 55 45 Figure 6 Figure 7 fflB Figure 9 Figure 10 Lightning i Difference 1

Claims (1)

[Claims] (1) In a position detection device that detects a position on a sheet resistance sheet indicated by a position indicator, a plurality of point electrodes provided on the sheet resistance sheet are arranged opposite to the sheet resistance sheet with a spacer interposed therebetween. a switching circuit for switching and selecting one of the plurality of point electrodes provided on the sheet resistance sheet; and a switching circuit for switching and selecting one of the plurality of point electrodes provided on the sheet resistance sheet; When the point electrodes are sequentially selected one by one by the switching circuit and the indicated point on the sheet resistance sheet, which is indicated by pressing the position indicator, comes into contact with the conductive sheet, the point electrodes on the sheet resistance sheet are selected one by one by the switching circuit. The resistance values between the two or more selected point electrodes and the indicated point are sequentially measured according to a predetermined procedure, the distance between the point electrode and the indicated point is calculated, and the distance between the two or more selected point electrodes and the indicated point is calculated. A position detection device characterized by comprising a position calculation section that calculates the position of the indicated point indicated by the position indicator on the sheet resistance sheet based on the distance between the point electrode and the indicated point.