JPH06109407A - Electromagnetic induction-type coordinate detection apparatus - Google Patents

Abstract

PURPOSE:To reduce an ineffective area and to reduce the external size of a tablet by a method wherein an induced voltage is first detected in a unit of one loop between two outermost comb teeth and it is then detected in two units of loops composed of the one loop and one loop adjacent to it. CONSTITUTION:When a part between individual comb teeth for a selector conductor 10 is designed as one loop, an induced voltage is first detected in a unit of one loop and it is then detected in two units composed of the one loop and one loop adjacent to it. As a result, induced voltages Va4, Va5 are detected in loops No. 1 and No. 2, the number of detections is two times, and it is judged that a coordinate indicator 5 is situated between both terminals T1, T2, i.e., in a position A at the outside (an ineffective area) of an effective area. Thereby, when a voltage at a prescribed voltage V1 or higher is detected continuously two times between identical comb teeth, a judgment technique that the indicator 5 is situated between the comb teeth is adopted, and the ineffective area is reduced to 172. As a result, the external size of a tablet 7 can be reduced and the effective area can be expanded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction type coordinate detecting device for detecting the position of a coordinate indicator such as a pen or a cursor on a tablet, and particularly to reduce an invalid area (invalid reading range) on the tablet. And an electromagnetic induction type coordinate detecting device.

[0002]

2. Description of the Related Art An electromagnetic induction type coordinate detecting device is a coordinate indicator such as a pen or a cursor, a device for applying a sine wave voltage to the coordinate indicator, an X-axis base on which a coordinate detecting wire is arranged, and a Y-axis base. A tablet having a selector zone (coordinate area) detection base on which an axis base and a selector conductor are arranged, and a signal generated on the coordinate detection conductor and the selector conductor is arithmetically processed to obtain an X coordinate and a coordinate indicator on the tablet. It is composed of a device for obtaining the Y coordinate.

FIG. 3 is a block diagram of such a conventional electromagnetic induction type coordinate detecting device, and FIG. 4 (a) shows the arrangement of coordinate detecting conductors and selector conducting wires on the tablet shown in FIG. 3 and the detection of induced voltage by the selector conducting wires. The figure which shows a scanning sequence, the same (b) is a graph of PD value based on the signal detected by the said coordinate detection conducting wire, and the same (c) is a waveform diagram of the voltage detected by the said selector conducting wire.

In these figures, 1 is an oscillator for generating a clock pulse of a predetermined frequency, 2 is a frequency divider for dividing the clock pulse of the oscillator 1, and 3 is a rectangular wave of the frequency divider 2 for converting it into a sine wave. A filter 4, an amplifier for amplifying this sine wave, and 5 a coordinate indicator having a coil 6 to which the amplified sine wave is applied, here a stylus pen. Reference numeral 7 is a tablet including bases for X-axis, Y-axis, and selector zone detection.

In FIG. 4 (a), 2 is arranged on the X-axis base.
One coordinate detection lead wire (hereinafter, these coordinate detection lead wires are referred to as cos wire and sin wire, respectively) and a selector lead wire arranged on the selector zone detection base are shown. In addition,
The arrangement of the cos line and the sin line in the Y-axis base and the relation with the selector conductor are the same as those of the X-axis base except that the arrangement positions thereof are different by 90 degrees. Therefore, only the X-axis base will be described below. .

In FIG. 4A, 8 is a cos line, 9 is a sin line,
Each of them is arranged in a meandering shape on the base with a phase difference of 90 electrical degrees. In this figure, the cos line 8 is shown by a solid line and the sin line 9 is shown by a broken line. Reference numeral 10 is a selector conductor wire arranged on the selector zone detection base,
It is formed in a comb shape. The selector conductor wire 10 is shown by a solid line, and the interval between the comb teeth thereof is equal to the interval of the cos wire 9 and the sin wire 10 for one period, and the selector wire 10 is arranged so as to be arranged as shown in FIG. The bases are stacked.
Tc is a terminal of cos line 8, Ts is a terminal of sin line 9, T0 to T4
Tn (T5 ... Tn are not shown) are terminals at the tips of the comb teeth of the selector conductor.

Returning to FIG. 3, when the stylus pen 5 is placed on the tablet 7, 11 indicates terminals Tc, Ts, T0-.
Selectors for sequentially switching and outputting the signals generated at T4 ... Tn, 12 and 13 are amplifiers for amplifying the signals generated on the cos line 9 and sin line 10, respectively, and 14 is an adder. The adder 14 includes a phase-shifting capacitor 14a and a resistor 14b,
Based on the signal generated on the cos line 9 and the signal generated on the sin line 10, for example, within one period of the cos line 9, a phase difference (corresponding to the distance between the reference position and the position where the stylus pen 5 is placed ( A sine wave having a phase difference with respect to the sine wave output from the filter 3 is output. 15 is an amplifier,
Reference numeral 16 is a comparator for discriminating the level of the sine wave signal. Reference numeral 17 is a counter which is set at the rising edge of the rectangular wave from the frequency divider 2 and is reset by the signal from the comparator 16, and the clock pulse from the oscillator 1 is introduced between the setting and the reset to determine the number. To count. This counted number is the above-mentioned phase difference, that is, the cos line 9
Is proportional to the distance from the reference position to the stylus pen 5 within one cycle of. Hereinafter, the distance corresponding to the counted number will be referred to as a PD value. This PD value N is shown in FIG.

Reference numeral 18 denotes each terminal T0 to T4 of the selector conductor wire 10.
... Tn is sequentially switched (scanned) in the selector 11 to amplify the signal output from the inter-comb tooth (selector zone) where the stylus pen 5 is placed, and 19 indicates the output value of the amplifier 18. A hold circuit for holding 20 is an A / D converter for converting the output value held in the hold circuit 19 into a corresponding digital value. Reference numeral 21 is a signal processing circuit that receives signals from the counter 17 and the A / D converter 20 and calculates the coordinates of the stylus pen 5 on the tablet 7 based on these signals.

That is, the signal of the selector conductor 10 detects which selector zone the stylus pen 5 is in, and the PD value obtained from the counter 17 determines the position of the stylus pen 5 within one cycle of the cos line 9. Since it becomes clear, the coordinates of the stylus pen 5 can be calculated from now on. The signal processing circuit 21 is the selector 1
It also issues a command to switch each terminal (including scanning of the selector terminal).

In such an electromagnetic induction type coordinate detecting device, when the stylus pen 5 is placed almost perpendicular to the surface of the tablet 7, the output signal appears only in the corresponding selector zone of the selector conductor 10, so that the selector is selected. There is no problem in zone detection.

However, in general, the stylus pen 5
In many cases, this is tilted considerably with respect to the surface of the tablet 7, and in this case, the selector conductor 10
, A signal is generated not only in the selector zone where the stylus pen 5 exists, but also in the adjacent selector zone.
Accurate coordinate detection becomes impossible. In order to avoid such a state, conventionally, the means shown in FIGS. 4A and 4C has been adopted for detecting the selector zone by the selector conductor 10. That is, instead of sequentially scanning the adjacent selector zones of the selector conductor 10,
This is a method of skipping one and scanning. Figure 4
As shown in (a), scanning is first performed between terminals T1 and T3, then between terminals T2 and T4, and then between terminals T3 and T5. Hereinafter, a loop between these terminals will be referred to as a loop, and a number indicating the loop number will be referred to as a loop number.
In FIG. 4 (a), loop 1 (loop N) is connected between terminals T1 and T3.
o. 1), loop 2 between terminals T2 and T4 (loop no.
2) ...

Such a scanning method (sequence) and a PD value (detected coordinate value within a period) obtained by the scanning method (sequence)
As a result, a voltage waveform that changes according to the position of the stylus pen 5 as shown in FIG. In the voltage waveform, if the voltage level for coordinate value determination is detected when the voltage level is higher than a predetermined voltage level V1, the stylus pen 5 determines which loop (selector zone) the detection frequency (one or two times). ), And the PD value is used to determine the coordinate value designated by the stylus pen 5. That is, when detecting the position B of the coordinate indicator, as shown in FIG. In No. 1, the voltage level of Vb1 is detected, and the loop No. In 2, the voltage level of Vb2 is detected, and the coordinate value determining voltage level is detected twice, so it is determined that the coordinate indicator is located in the selector zone between the terminals T2 and T3.

As shown in FIG. 4A, the comb teeth of the selector conductor 10 (the selector conductor 10 to the terminals T0 and T1) are required even outside the effective area (effective reading range) (ineffective area). Is for correctly determining that the stylus pen 5 is placed outside the effective area. That is,
Position A of the stylus pen 5 placed outside the effective area
, The loop N is detected as shown in FIG.
o. At 0, the voltage level of Va1 is detected and loop N
o. 1, the voltage level of Va2 is detected, and the number of times the voltage level for coordinate value determination is detected is two, so the stylus pen 5 is located in the selector zone between the terminals T1 and T2, and is outside the effective area (invalid). Area).

Here, in the sequence of the prior art, the terminal T0
When the selector conducting wire 10 (comb tooth) to is removed and the invalid area is reduced, as shown in FIG.
o. When the position A of the stylus pen 5 is detected, the number of detections of the coordinate value determining voltage level is only one detection of the voltage level Va3. The PD value is used for the selector zone determination when the number of detections of the voltage value for determining the coordinate value is one.
If the D value is less than 512 (up to 1024),
In the case of the rear selector zone, 512 or more, it is determined to be the front selector zone, and at the position A of the stylus pen 5,
Since the PD value is less than 512, it is erroneously determined as the selector zone (position B) between T2 and T3 in the effective area.

[0015]

Therefore, in the conventional device, it is determined whether the position where the stylus pen 5 (coordinate indicator) is placed is outside or inside the effective area (effective reading range). On each outer part,
That is, the selector conductor 1 is provided on each of the origin side and the maximum value side.
Two 0s (comb teeth) (each selector conductor wire 10 (comb teeth) to the terminals T0 and T1 and each selector conductor wire 10 (comb teeth) to the terminals Tn-1 and Tn) are required to be laid. . Therefore, there is a problem in that it is difficult to reduce the invalid area and it is difficult to reduce the external dimensions of the tablet 7 (enlarge the effective area when the external dimensions are the same).

An object of the present invention is to provide an electromagnetic induction type coordinate detecting device capable of reducing the invalid area and reducing the outer dimensions of the tablet (enlargement of the effective area when the outer dimensions are the same). is there.

[0017]

The above object is to provide a coordinate indicator having a coil excited by an AC power source, and an electrical angle 9
Two coordinate detection lead wires having a phase difference of 0 degree and insulated from each other and arranged in a meandering manner on the base, and two coordinate detection lead wires insulated from the two coordinate detection lead wires and arranged on the base, and the two One of the coordinate detection conductors of the coordinate detection conductors
The comb-shaped selector conducting wire formed by matching the periodic interval and the comb-tooth spacing, and the one coordinate by the induced voltage signals of the two coordinate detecting conducting wires when the coordinate indicator is placed on the base. The position of the coordinate indicator from the reference position within one cycle of the detection conductor, and the periodic range of the two coordinate detection conductors are similarly detected by the induced voltage of the selector conductor, and the coordinates are detected from these two detection results. In an electromagnetic induction type coordinate detection device comprising a signal processing circuit for detecting the position of the indicator as a coordinate value, for determining which comb tooth of the selector conducting wire the voltage induced in the selector conducting wire is. Scanning of the induced voltage detection between the comb teeth of
When one inter-comb-tooth-to-one loop is formed, between the two outermost comb-tooths, first one loop unit, then one loop and two adjacent loops, two loop units thereafter. The signal processing circuit includes scanning means for detecting the induced voltage by shifting one loop by one loop, and the signal processing circuit detects the voltage of a predetermined value or more continuously twice between the same comb teeth during the scanning. This is accomplished by making a determination that the coordinate indicator is in between.

[0018]

In the electromagnetic induction type coordinate detecting device having two coordinate detecting wires and one selector wire (one axis of the coordinate axis), conventionally, the boundary between the adjacent comb teeth of the selector wire (to each terminal T1 to Tn). In order to prevent erroneous detection in the vicinity of the selector conductor (comb tooth), scanning of induced voltage detection between the comb teeth is performed by shifting one loop by two loops when one loop is formed between the comb teeth. (sequence)
Is taking. When this scanning method is adopted, it is determined that the coordinate indicator is located between the comb teeth when a voltage equal to or higher than a predetermined value is continuously detected twice between the same comb teeth. Therefore, conventionally, the comb teeth of the selector conductor 10 for two loops (the selector conductor 1 to the terminals T0 and T1) are provided outside the effective area (effective reading range) (ineffective area).
0) was required (see FIG. 4 (a)).

The induced voltage detection scanning means according to the present invention performs scanning of induced voltage detection between comb teeth for determining which comb tooth of the selector conductor the voltage induced in the selector conductor is. When one inter-comb-tooth-to-one loop is formed, between the two outermost comb-tooths, first one loop unit, then one loop and two adjacent loops, two loop units thereafter. It is performed by shifting one loop by one loop unit. That is, in the present invention, as a scanning method for detecting the induced voltage between the comb teeth, basically the same method as the conventional method is adopted, but the two outermost comb teeth (first and last scanning portions) are scanned by the conventional method. 1
Detection was performed in the unit of / 2 (one loop unit), and the detection pitch was the same as that of the conventional method after the second time.

According to this, when a voltage equal to or higher than a predetermined value is continuously detected twice between the same comb teeth, the ineffective area is determined while the coordinate indicator is positioned between the comb teeth. Is half that of the conventional one (only the comb teeth of the selector conductor 10 for one loop (the selector conductor 10 to the terminal T1) are required, and the selector conductor 10 to the terminal T0 is not necessary), and the external dimensions of the tablet are reduced. It is possible to increase the size and effective area.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of an embodiment of an electromagnetic induction type coordinate detecting device according to the present invention, in which (a) is the arrangement of coordinate detecting conductors and selector conducting wires on the tablet shown in FIG. 2 and induced voltage detection by the selector conducting wires. Is a graph showing a PD value based on a signal detected by the coordinate detection conducting wire, and (c) is a waveform diagram of a voltage detected by the selector conducting wire. In addition, in FIG.
The origin coordinate side of the X axis is shown as a representative example.

In FIG. 1, Tc, Ts, T1 to T4
(... Tn) and 5 are the same as in FIG. 8, 9 and 10 also show the cos line, the sin line and the selector conductor as in FIG. 4, but here the outermost side (origin side and maximum value side, here the origin side) is one cycle compared to FIG. Has been reduced. That is, there is no comb tooth of the selector conductor 10 for one loop (the selector conductor 10 to the terminal T0 in FIG. 4), and the invalid area is reduced to 1/2 of that in the conventional device of FIG.

FIG. 2 is a block diagram showing a main part of an embodiment of the electromagnetic induction type coordinate detecting device according to the present invention. In FIG. 2, 5 to 7, 11, and 18 to 20 are the same as those in FIG. is there. Reference numeral 21 also shows a signal processing circuit similarly to FIG. 3, but here, when the scanning for detecting the induced voltage between the comb teeth (selector zone) is one loop between the comb teeth, the two outermost combs are shown. The inter-tooth space is provided with an induced voltage detection scanning unit that first shifts by 1 loop unit, then by 2 loop units of 1 loop and 1 loop adjacent thereto and thereafter by 2 loop units by 1 loop. Then, in such scanning, when a voltage of a predetermined value V1 or more is continuously detected twice between the same comb teeth, it is determined that the stylus pen 5 is located between the comb teeth (selector zone). Is.

Next, the operation of the device of the present invention will be described. With respect to one coordinate axis, in an electromagnetic induction type coordinate detection device provided with two coordinate detection lead wires and one selector lead wire, a boundary between adjacent comb teeth of the selector lead wire (each terminal T1
In order to prevent erroneous detection in the vicinity of the selector conducting wire (comb teeth) to Tn, scanning of the induced voltage between the comb teeth is performed in units of two loops in units of two loops. There is a method of shifting. When this scanning method is adopted, it is determined that the coordinate indicator is located between the comb teeth when a voltage equal to or higher than a predetermined value is continuously detected twice between the same comb teeth. Therefore,
In the conventional device, the comb teeth of the selector conductor 10 for two loops (the selector conductor 10 to the terminals T0 and T1) are arranged outside the effective area (effective reading range) (ineffective area) (FIG. 4A). reference).

The induced voltage detection scanning means according to the present invention performs the induced voltage detection scanning between the comb teeth for determining which of the comb teeth of the selector conductor 10 the voltage induced in the selector conductor 10 is, When one inter-comb-tooth-to-one loop is formed, between the two outermost comb-tooths, first one loop unit, then one loop and two adjacent loops, two loop units thereafter. It is performed by shifting one loop by one loop unit. That is, in the present invention, as shown in FIG. 1A, scanning is first performed between terminals T1 and T2, then between terminals T1 and T3, and then between terminals T2 and T4. Hereinafter, the loop between these terminals, and the number indicating the loop number is called the loop number, and in FIG. 1A, between the terminals T1 and T2, the loop 1 (loop No. 1) and the terminals T1 and T3 are shown. Between loop 2 (loop N
o. 2) ...

Then, according to the scanning method (sequence) and the PD value (detected coordinate value within the period) obtained by such a scanning method (sequence), the position of the stylus pen 5 is changed as shown in FIG.
A changing voltage waveform is obtained as shown in (c). Then, in this voltage waveform, when the voltage value for coordinate value determination is detected when the voltage level is higher than a predetermined voltage level V1, the stylus pen 5 is positioned in which loop (selector zone) depending on the number of times of detection (twice). The coordinate value designated by the stylus pen 5 is determined by determining whether or not to do so and using the PD value for this. That is, when detecting the position B of the coordinate indicator, as shown in FIG. In No. 1, the voltage level of Vb5 is detected, and the loop No. In 2, the voltage level of Vb6 is detected, and the stylus pen 5 is determined to be located in the selector zone between the terminals T2 and T3 because the number of times of detecting the coordinate value determining voltage level is two times.

As shown in FIG. 1A, comb teeth of the selector conductor 10 (selector conductor 10 to the terminal T1) are required even outside the effective area (effective reading range) (ineffective area) (however, in the conventional device). (1/2 of the area) is for correctly determining that the stylus pen 5 is placed outside the effective area. That is, when detecting the position A of the stylus pen 5 placed outside the effective area, as shown in FIG. At 0, the voltage level of Va4 is detected, and the loop No. In No. 1, the voltage level of Va5 is detected, and the stylus pen 5 is connected to the terminal T1−
Since it is located in the selector zone between T2, it is determined to be outside the valid area (invalid area).

While the device of the present invention can detect the position A of the stylus pen 5 placed outside the effective area without any error, it can be understood by comparing FIGS. 1 (a) and 4 (a). As described above, the outside (ineffective area) of the effective area (effective reading range) of the device of the present invention (FIG. 1A) is half that of FIG. 4A.

According to this, when the voltage of the predetermined value V1 or more is continuously detected twice between the same comb teeth (selector zone), the stylus pen 5 is positioned between the comb teeth. On the other hand, the number of invalid areas is half that of the conventional one (only the comb teeth of the selector conductor 10 for one loop (the selector conductor 10 to the terminal T1) are required, and the selector conductor 10 to the terminal T0 is unnecessary), and the tablet 7 It is possible to reduce the outer dimensions of the device or expand the effective area.

[0030]

As described above, according to the present invention, one meandering coordinate detection lead wire and one comb-teeth-shaped selector lead wire are provided for each coordinate axis. In order to prevent erroneous detection in the vicinity of the boundary between the comb teeth, a method of scanning the induced voltage between the comb teeth by shifting the comb teeth by one loop in units of two loops is adopted. In the inductive coordinate detection device, the two outermost comb teeth (first (origin side) and last (maximum value side) scanning portion) are detected in 1/2 unit (1 loop unit) of the conventional method. Therefore, when the voltage equal to or higher than a predetermined value is continuously detected twice between the same comb teeth, the invalid area is determined by the determination method that the coordinate indicator is positioned between the comb teeth. Half done, outside the tablet There is an effect that attained the reduction or enlargement of the effective area size.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the device of the present invention.

FIG. 2 is a block diagram showing a main part of an embodiment of the device of the present invention.

FIG. 3 is a block diagram showing an embodiment of a conventional device.

FIG. 4 is an explanatory diagram of a conventional device.

[Explanation of symbols]

5 stylus pen (coordinate indicator) 6 coil 7 tablet (base) 8 cos line (coordinate detection conducting wire) 9 sin line (coordinate detection conducting wire) 10 selector conducting wire 21 signal processing circuit (induced voltage detecting scanning means) V induction of selector conducting wire Voltage (selector conductor detection voltage)

Claims (1)

[Claims] 1. A coordinate indicator provided with a coil excited by an AC power source, and two coordinate detection conductors having a phase difference of 90 degrees in electrical angle and insulated from each other and arranged in a meandering shape on a base. A comb tooth formed on the base so as to be insulated from the two coordinate detection conductive wires, and formed so that one cycle interval of one of the two coordinate detection conductive wires and the comb tooth interval match. -Shaped selector conductor wire and the coordinate indicator from the reference position within one cycle of the one coordinate detection conductor wire by the induced voltage signals of the two coordinate detection conductor wires when the coordinate indicator is placed on the base. And a signal processing circuit for detecting the position of the coordinate indicator as a coordinate value from the detection results of these two detection ranges of the two coordinate detection conductive lines by the induced voltage of the selector conductive line. Be prepared In the electromagnetic induction type coordinate detecting device according to the above, scanning of induced voltage detection between comb teeth for determining which comb tooth of the selector conductor the voltage induced in the selector conductor wire is, When one loop is used, first between the outermost two comb teeth is one loop unit, then one loop and two adjacent loops are two loop units, and thereafter, one loop is two loop units. The signal processing circuit is provided with scanning means for detecting induced voltage, which shifts by one by one, and when the voltage of a predetermined value or more is continuously detected twice between the same comb teeth in the scanning, the coordinate instruction is provided between the comb teeth. An electromagnetic induction type coordinate detection device, characterized in that it is determined that the vessel is located.