JPH02110616A - Coordinate detector - Google Patents

Abstract

PURPOSE:To improve positional precision by connecting a loop (large loop) constituted of a pair of coordinate detecting electric wires to a signal detection circuit as switching it by the width of a single loop, and deciding a coordinate according to the change and the size of a signal from the signal detection circuit. CONSTITUTION:A CPU 5 switch-controls each selector switch 4a, 4b, and simultaneously, decides whether the signal is present or absent in the large loop being switch-connected to the signal detection circuit 3 at that time, and in the case of presence, it stores successively data corresponding to the position of the large loop in a RAM 5c. The decision of the presence or the absence of the signal is performed on the basis of whether the output value of a peak hold circuit 3f at each switch-connecting position of the switches 4a, 4b exceeds reference voltage or not. A switching method is as follows. Namely, at first, the large loop position (a) to (b) of a comb-shaped electrode 1 is detected, and next, (b) to (c), and next, (d) to (e) is detected. By switching the large loop by the width of the single loop in this way, it can be found that a coordinate indicating pen 2 is located at the loop position (c). Similar detection is executed for Y axis, and finally, result is outputted as two-dimensional coordinate values.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coordinate detection device, and in particular to a coordinate detection device suitable for use in toys, for example, in which simplification of configuration is given priority over high accuracy. be.

[Conventional technology]

Electromagnetic induction coordinate detection devices are usually used for office purposes.

It is designed for industrial use, and although it has high precision, the structure is complex and expensive, and it is not suitable for use in toys, for example, where simplification of the structure, or in other words, lowering the price, is prioritized over high accuracy.

Therefore, conventionally, a coordinate detection device as shown in FIG. 3 has been considered. In FIG. 3, reference numeral 1 denotes a comb-shaped electrode for detection in the X-axis direction, and a plurality of detection conductive wires 1a, one end of which is commonly connected, are arranged in parallel at a predetermined, equal pitch of about 0.5 to 5 m, for example. It is formed by wiring on an insulating substrate (not shown). Reference numeral 2 denotes a pen-shaped coordinate indicator (coordinate indicating pen) which supplies a guiding signal to the comb-shaped electrode 1 to indicate a coordinate position, and here it is constructed with a built-in sine wave oscillator. 3 is a pair of adjacent and opposing coordinate detection conductive wires la, la of the comb-shaped electrode 1;
This is a signal detection circuit that detects whether a signal from the coordinate indicating pen 2 is guided into the loop formed by the above, and is composed of an amplifier 3a + filter 3b, a reference voltage source 3c, and a comparator 3d. Reference numeral 4 denotes a switching circuit that sequentially switches the loops connected to the signal detection circuit 3, and is composed of changeover switches 4a and 4b using, for example, a multiplexer. Reference numeral 5 denotes a coordinate determination circuit that controls switching of the switching circuit 4 and determines the coordinate position indicated by the coordinate indicating pen 2 based on the switching connection position and the signal from the signal detection circuit 3; It consists of ROM5b. 6 is an output terminal.

In such a conventional device, when detecting the X coordinate (position), the changeover switch 4a,
Switching control is performed in conjunction with 4b. When the coordinate indicating pen 2 is located at a position between the detection conductive lines 1a and la of the comb-shaped electrode 1, that is, at any of the loop positions a'-g, the sine wave signal guided signal from the coordinate indicating pen 2 is It is output from the comb-shaped electrode 1.

The output signal from the comb-shaped electrode 1 is amplified by an amplifier 3a and smoothed by a filter 3b. For example, when the coordinate indicating pen 2 is at the loop position e of the comb-shaped electrode 1, the switch 4
When a is connected to the C terminal and switch 4b is connected to the C terminal, the output signal from the comb-shaped electrode 1 is connected to the switch 4a, 5b.
is larger than when it is at other terminals. Then, the output signal of the amplifier 3a also increases, and the output voltage of the filter 3b exceeds the output voltage (saw voltage) of the reference voltage source 3c, and the output signal of the comparator 3d changes from a low level to a high level. Thereby, the CPU 5a determines that the position Me is the coordinate position, and outputs it from the output terminal 6.

The Y coordinate (position) is also detected through a similar operation and output from the output terminal 6.

In addition, in FIG. 3, regarding the comb-shaped electrode and the changeover switch, the comb-like electrode 1 for X-axis direction detection and the changeover switch 4 are shown.
Although only a and 4b are shown in the diagram, they are actually equipped with a comb-shaped electrode and a changeover switch for detecting the Y-axis direction, and their operation is also the same as the X-axis direction.
This is the same as for axial direction detection.

According to such a conventional device, the intended purpose is achieved, such as a simple structure, low cost, and suitable for use as a toy.

[Problem to be solved by the invention]

However, in such a conventional device, when the coordinate indicating pen 2 is placed on the coordinate detecting conductive wire 1a of the comb-shaped electrode 1, no signal is output from the comb-shaped electrode 1, and therefore the coordinates cannot be detected, which is inconvenient. There was a problem. This problem can be solved to some extent by making the diameter of the conductive wire 1a for coordinate detection of the comb-shaped electrode 1 extremely thin, but this increases the cost.

Moreover, it was not possible to eliminate all undetectable points. Also, the coordinate indicating pen 2 was not able to detect the loop position a- of the comb-shaped electrode 1.
It is possible to detect whether it is in any of g.

It was not possible to detect the position in the horizontal direction in the figure in a certain loop position, for example, loop position e.

In order to increase the detection position accuracy in this case, the width (pitch) of the loop formed by the pair of adjacent and opposing detection conductive wires 1a, la should be made narrower, but this does not make it possible to The number of detection conductive wires 1a per unit length in the left and right direction increases. For this reason, not only does the configuration of the comb-shaped electrode 1 become complicated, but there is also a large possibility that the pen 2 will be located on the detection conductive wire 1a, which will exacerbate the problems described above. there were.

According to the present invention, coordinates can be detected even when the coordinate indicating pen is on the conductive wire for coordinate detection of the comb-like electrode, and therefore there is no need to make the wire of the comb-like electrode extremely thin, and the number of conductive wires for coordinate detection is An object of the present invention is to provide a convenient and low-cost coordinate detection device that can improve detection position accuracy without increasing the accuracy.

[Means to solve the problem]

The above object is a coordinate detection device comprising a comb-shaped electrode, a coordinate indicator, a signal detection circuit, a switching circuit, and a coordinate position determination circuit, wherein the switching circuit includes at least one conductive conductor for coordinate detection. A loop (large loop) formed by a pair of coordinate detection conductive wires facing each other with a wire interposed between them is sequentially switched with the width of a loop (single loop) formed by a pair of adjacent and opposing coordinate detection conductive wires. is connected to the signal detection circuit, and the coordinate determination circuit determines the coordinate position indicated by the coordinate indicator based on the change and magnitude of the signal from the signal detection circuit within a switching cycle period by the switching circuit. This is achieved by configuring the

[For production]

Even if the coordinate indicator is on the conductive line, the signal from the coordinate indicator is always guided to the large loop. Furthermore, if the large loops are sequentially switched with the width of the single loop and connected to the signal detection circuit, the position where the signal is guided by the coordinate indicator can be specified, that is, the coordinate position can be detected using the signal within the switching cycle period. This can be easily determined based on the transition and magnitude of the change in the signal from the detection circuit.

〔Example〕

The present invention will be described in detail below with reference to the drawings. 1st
FIG. 1 is a circuit diagram showing an embodiment of the coordinate detection device according to the present invention, in which reference numerals 1 and 6 indicate comb-shaped ffi poles and output terminals similar to those in FIG. 2, 3.4, and 5 also show a coordinate indicating pen, a signal detection circuit, a switching circuit, and a coordinate determination circuit as in FIG. 3, but according to the present invention, they are constructed as follows.

That is, the coordinate indicating pen 2 includes two Schmitt trigger inverters 11, a charging/discharging circuit consisting of a resistor R1, and a capacitor C1.
energizes and operates as a transmitter. If the Schmidt trigger inverter IL is configured with 0MO8 elements, the power consumption will be reduced, so it can be operated satisfactorily even with a dry battery BAI, and the coordinate indicating pen 2 can be made cordless. Note that the capacitor C2 is for waveform shaping.

Furthermore, the frequency of the oscillator is set sufficiently higher than that frequency in order to avoid the mixing of noise from the CRT device used as the indicating device of the coordinate detection device, so the frequency of the 0MO8 element is actually high speed. CMO8
(HCMO8) element is used.

The signal detection circuit 3 includes an amplifier 3a and a filter 3b.

It consists of a reference voltage source 3c, a comparator 3d, an amplifier 3e, a peak hold circuit 3f, and an A/D conversion circuit 3g.

In this case, amplifier 3e amplifies the output signal of filter 3b. The peak hold circuit 3f detects the peak value of a signal within a fixed period (switching cycle period) defined by a reset circuit (not shown) controlled by the CPU 5a, which will be described later. The A/D conversion circuit 3g performs A/D conversion on the peak value. The other circuits (3a to 3d) are the same as those shown in FIG.

The switching circuit 4 is composed of changeover switches 4a and 4b using, for example, a multiplexer, as in the conventional device. In this case, the selector switches 4a and 4b are set to one or more (
Here, a loop (large loop) formed by a pair of coordinate detection conductive wires 1a and la facing each other is sequentially switched and connected to the signal detection circuit 3 with one coordinate detection conductive wire 1a interposed therebetween. It is something. At this time, the large loop is connected to the signal detection circuit 3 by sequentially switching the width of the loop (single loop) formed by a pair of adjacent and opposing conductive wires 1a and 1a for coordinate detection.

The coordinate determination circuit 5 includes a CPU 5a, a ROM 5b, and an RA.
Consisting of M5c. In this case, when the peak value from the peak hold circuit 3e exceeds the reference voltage, the RAM 5c stores the changeover switch connection position at that time, that is, which large loop position. The coordinate determination circuit 5 also performs an A/D of the peak value when the reference voltage is exceeded.
The output value of the conversion circuit 3g is stored in the RAM 5c;
Loop position W1 (single loop) from the loop position coordinate position data table registered in M5c (table representing position data in the horizontal direction in the figure within a single loop for the A/D converted value of the peak value) This is for reading internal coordinate position data. The other circuits (5a, 5b) are the same as those shown in FIG. 3, but the loop position coordinate position data table may be registered in the ROM 5b.

Incidentally, the pitch of a single loop of the comb-shaped electrode 1 is usually 1, 5I.
Ifi is preferably about 20 mm, which is about 2 to 10 times the coil diameter of the 5-coordinate indicating pen 2.

Next, the operation of the above-mentioned apparatus of the present invention will be explained with reference to FIG. In FIG. 2, a coordinate detection operation is started at step 100. CPU5a.

As well as controlling the switching of each changeover switch 4a, 4b.

At that time, it is determined whether there is a signal in the large loop connected to the signal detection circuit 3, and if there is a signal, the RAM 5
c stores data corresponding to the position of the large loop (see steps 101 to 112). The presence or absence of a signal in the large loop is determined by the changeover switch 4a.
, 4b, the output value (peak value) of the peak hold circuit 3f at each switching connection position exceeds the reference voltage (output voltage of the reference voltage source 3c).

The method of switching the changeover switches 4a and 4b at this time is, for example, by first detecting the large loop position a-b of the comb-shaped electrode 1;
Next, detect b '' c, then c '' d, then d '' e, and so on, and so on.
The position can be detected even when placed on the coordinate detection conductive wire 1a of the comb-shaped electrode 1. Instead of doing this,
When the loop position Ha is first detected, then b, then C, etc. 1, for example, the coordinate indicating pen 2 is placed on the coordinate detecting conductive wire 1a connected to the B terminal of the changeover switch 4a. In this case, no voltage is induced at either loop position a or b, making it impossible to detect the position. In addition, 1
The range of the loop position detected by the switching operation of the comb-shaped electrode 1, in other words, the size of the large loop, is not limited to only two as in the above embodiment, but one loop position [a Detect ~C, then b-d, then c-e,
Next, detect d to f, and so on. Or even more.

In this way, after all the switching of the changeover switches 4a and 4b is completed, the CPU 5a calculates which loop position the coordinate indicating pen 2 is located based on the signal presence/absence data stored in the RAM 5c. (See step 113). In this embodiment, the large loop positions b ” c and c
Since the signal is present when "d" is detected, it can be seen that the coordinate indicating pen 2 is placed at the loop position Ha.The coordinate indicating pen 2 is placed on the coordinate detecting conductive wire 1a of the comb-shaped electrode. In case.

Since a signal is present when the position of the large loop sandwiching the conductive wire 1a is detected, coordinate detection is also possible in this case.

Next, the changeover switches 4a and 4b are connected again to the switching positions B, F, C, and E when it was determined that the signal was present, and the output value (peak value) of the peak hold circuit 3f at that position is A/
Each D conversion value is stored in the RAM 5c (see steps 114 to 115), and based on the surface memory values, the coordinate position within the loop position is determined from the loop position coordinate position data table registered in the RAM 5c. Step 100
Return to

In addition, in FIG. 1, regarding the comb-shaped electrode and the changeover switch, the comb-like electrode 1 for detecting the X-axis direction and the changeover switch 4 are shown.
Although only a and 4b are shown in the diagram, they are actually equipped with a comb-shaped electrode and a changeover switch for detecting the Y-axis direction, and their operation is also the same as the X-axis direction.
This is the same as for axial direction detection (step 117 in Figure 2).
), and are finally output as two-dimensional coordinate values.

Further, in the above-mentioned embodiment, when all the switching of the changeover switches 4a and 4b is completed, the CPU 5a is switched to the RAM 5c.
The loop position of the coordinate indicating pen 2 is calculated based on the signal presence/absence data stored in the step 11.
3), the changeover switches 4a and 4b are connected again to the switching position when it was determined that the signal was present, and based on the A/D conversion value of the output value (peak value) of the peak hold circuit 3f there. Although the coordinate position within the loop position is determined (see steps 114 to 116), the present invention is not limited to this. For example, steps 101-112
In each case, the A/D converted values of the output value (peak value) of the peak hold circuit 3f at each time are sequentially stored in the RAM 5c, and the coordinate position within the loop position is determined based on these values. According to this, it is not necessary to connect the changeover switches 4a, 4b again to the switching positions when it is determined that the signal is present after all the changeovers of the changeover switches 4a, 4b are completed.

〔Effect of the invention〕

According to the present invention, a loop (large loop) formed by a pair of coordinate detection conductive wires facing each other with one or more coordinate detection conductive wires interposed therebetween is formed by a pair of adjacent coordinate detection conductive wires facing each other. The width of the formed loop (single loop) is sequentially switched and connected to the signal detection circuit, and the coordinate indicator is used to indicate the change and magnitude of the signal from the signal detection circuit within the switching period of the switching circuit. Since the coordinate position is determined, coordinates can be detected even if the coordinate indicating pen is on the conductive line for coordinate detection of the comb-shaped electrode, and there is no need to make the line of the comb-shaped electrode extremely thin. This has the effect of providing a convenient and low-cost coordinate detection device that can improve detection position accuracy without increasing the number of conductive wires for coordinate detection.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the device of the present invention, FIG. 2 is a flowchart for explaining the operation of the same device, and FIG. 3 is a circuit diagram of a conventional device. DESCRIPTION OF SYMBOLS 1... Comb-shaped electrode, 1a... Conductive wire for coordinate detection, 2.
...Coordinate indicating pen (coordinate indicator), 3... Signal detection circuit, 3a... Amplifier, 3c... Reference voltage source, 3
d...Comparator, 3e...Amplifier, 3f...Peak hold circuit, 3g...A/D conversion circuit, 4...
Switching circuit, 4a, 4b switching switch,...coordinate determination circuit, 5a...CPU, 5b-ROM, 5cmRA
M, 6...output terminal, 8~g-...loop position. Figures 1 and 2

Claims (1)

[Claims] 1. A comb-shaped electrode formed by wiring multiple conductive wires for coordinate detection in parallel at equal pitches, each end of which is connected in common, and a coordinate indicator that indicates the coordinate position by giving a guiding signal to the comb-shaped electrode. a signal detection circuit for detecting whether a signal from the coordinate indicator is guided to a loop formed by a pair of opposing coordinate detection conductive wires of the comb-shaped electrode; and a signal detection circuit connected to the signal detection circuit. a switching circuit that sequentially switches the loops, and a switching circuit that controls switching by applying a switching control signal to the switching circuit, and a coordinate position indicated by a coordinate indicator based on the switching control signal and a signal from the signal detection circuit. In the coordinate detecting device, the switching circuit connects a loop formed by a pair of coordinate detecting conductive wires facing each other with one or more coordinate detecting conductive wires interposed between adjacent coordinate detecting conductive wires. The coordinate determination circuit is connected to the signal detection circuit by sequentially switching the loop width formed by a pair of opposing conductive wires for coordinate detection, and the coordinate determination circuit is configured to detect the signal from the signal detection circuit within one switching period by the switching circuit. A coordinate detection device characterized by determining a coordinate position indicated by a coordinate indicator based on changes and magnitudes of signals.