JPS63187321A - Coordinate reader - Google Patents

Abstract

PURPOSE:To miniaturize a device, to reduce its cost and also, to reduce a read error depending on a moving speed of a coordinate indicator, by determining and reading the coordinate position of the coordinate indicator by an induced voltage detected by an induced voltage detecting circuit. CONSTITUTION:A microposition detecting circuit 19 for constituting a coordinate detecting circuit 18 detects a microposition, based on the induced voltage of each sense line of a microposition sense line group 51 and the result of decision of polarity. Also, a rough position detecting circuit 20 detects a rough position, based on the induced voltage of each sense line of a rough position sense line group 61 and the microposition obtained from the microposition detecting circuit 19, and by adding the values of both of them, a position in the X axis direction of a coordinate indicator 4 is determined. In the same way, based on the induced voltage of each sense line of a microposition sense line group 71 and a rough position sense line group 81, and the result of decision of polarity, a position in the Y axis direction of the coordinate indicator 4 is determined. In such a way, the device can be miniaturized, the cost can be reduced, and also, a coordinate read error can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a coordinate reading device as a graphic input device, that is, an arbitrary point in a coordinate area having intersecting X and Y coordinate axes, can be detected using a coordinate indicator. The present invention relates to a coordinate reading device that can determine and read the X and Y coordinates of a designated point when designated.

More specifically, as a coordinate reading device, a plurality of sense lines are stretched around the coordinate area, and the detection output of the sense lines of the alternating magnetic field generated from the coordinate indicator is switched to a common detection circuit for each sense line. In an electromagnetic induction type coordinate reading device that reads data and determines the X and Y coordinates from the reading output, it is possible to reduce coordinate reading errors that occur depending on the moving speed of the coordinate indicator (drawing speed of figures). The invention relates to a label reading device.

[Conventional technology]

Hereinafter, in order to facilitate understanding of the explanation in this specification,
I will explain the general operation method of an electromagnetic induction type coordinate reading device without fail.

FIG. 23 is an explanatory diagram showing a rough operating method of the electromagnetic induction type coordinate reading device. In the figure (A), AR is a coordinate area having X and Y coordinates that intersect with each other. IN
It is assumed that is a point indicated by a coordinate indicator moving in the X coordinate direction.

The purpose is to determine and read the X and Y coordinates of the point designated by this coordinate designated point IN.

Therefore, as shown in Figure 23 (b), the coordinate area AR
, the periodic regions with an interval of 2P are shifted by, for example, an interval of P/4 along the X coordinate axis direction to form LL, L2 .
I, set as 3.1-4... Each periodic region has the magnitude and polarity of the alternating induced voltage signal (coordinate indicated The sense lines are arranged at intervals of P/4 so that the alternating magnetic field generated by the device changes periodically (the length of one cycle is 2P).
Each of these sense lines is called a fine position sense line.

Since there are a plurality of fine position sense lines, one set for each periodic region, the whole is called a fine position sense line group.

Next, as shown in FIG. 23(c), the coordinate area AR
, coarse regions Ml, M2 . M
A sense line that can detect when the source of the alternating magnetic field (point IN indicated by the coordinate indicator) is located within each coarse area (this is called a coarse position sense line). Place it. There are also a plurality of sets, one set for each coarse area, so the whole is called a coarse position sense line group.

- By detecting and processing the induced voltage signals from the fine position sense line group and the coarse position sense line group, the X coordinate of the coordinate indicated point IN can be determined. Regarding the Y coordinate, the Y coordinate can be determined in exactly the same way by providing a periodic region and a coarse region in the Y direction, and arranging a fine position sense line group and a coarse position sense line group.

From the following, it seems that the operating method of the electromagnetic induction type coordinate reading device has been understood, albeit roughly, so we will now proceed with the explanation of the prior art.

The conventional electric induction type coordinate reading device was developed by Japanese Patent Publication No. 53-348.
As described in Publication No. 55, two fine position sense lines N,, nc meandering in a rectangular wave shape with a period of pitch P are laid on a flat plate with a shift of P/4 from each other. Due to the phase relationship between the composite voltage signal of the alternating induced voltage induced in the sense line and the excitation alternating voltage signal that excites the excitation winding built into the coordinate indicator, the coordinates within the pinch P, within the repetition period of the so-called rectangular wave shape, are determined. Obtain position information Pθ of the indicator, and detect in which cycle the coordinate indicator is located by detecting the thickness of the alternating induced voltage induced in the loop-shaped coarse position sense line laid in each repetition cycle. However, it is detected by the installation position of the coarse position sense line that gives the maximum value.

A coordinate reading device based on this principle, Tokuko Sho 5:3-3
The coordinate reading device described in Publication No. 4855 includes a fine position sense line βSX+ 1cxs around the X axis, a fine position sense line 'SY+'CY around the Y axis, a coarse position sense line around the X axis, and a coarse position sense line around the Y axis. Position information P within the period is calculated based on the alternating induced voltage signal of the flat plate on which the line is laid and the fine position sense line.
Fine position detection means for time-divisionally detecting θ with respect to the X-axis and Y-axis; Providing a rough position detection means for the maximum Y-axis circumference similar to the X-axis circumference,
At the same time as detecting the position information Pθ, coarse position sense lines giving the maximum induced voltages on the X-axis and Y-axis are detected in parallel.

As mentioned above, by installing each detection means in parallel, it is possible to detect the position (coordinate value) of the X-axis and Y-axis coordinate indicator in a short time, and the coordinate reading speed (sampling speed)
In addition, since the difference between the X-axis coordinate detection time and the Y-axis coordinate detection time is small, the detected coordinate value (XT, YT ) and the actual coordinate indicator position (
The difference (ΔX, ΔY) from XT, y, ) is small. (These differences ΔX and ΔY are called reading errors that depend on the moving speed of the coordinate indicator. Details of this will be described later.) However, since multiple detection means are installed in parallel, the scale of the device increases and The price becomes expensive.

As a method to solve this problem, the induced voltages of the fine position sense lines and coarse position sense lines for the X-axis circumference and Y-axis are sequentially scanned in a time-division manner using one induced voltage detection circuit. Based on the detected induced voltage of each sense line, coordinate values of the X-axis and Y-axis can be calculated and detected.

However, in this method, the induced voltage of each sense line is sequentially scanned and detected, so the fine position sense line around the X axis, the coarse position sense line, the fine position sense line for the Y axis, and the coarse position sense line are When scanning is performed sequentially, the average sense time T of the sense line around the X-axis, and the average sense time T of the sense line around the Y-axis.
A difference Δt is generated between V- and V-. This Δt increases as the number of coarse position sensing lines increases, that is, as the coordinate reading range increases.

Here, when the coordinate indicator is moving at a speed V in the X-axis direction, and a speed V in the YI-axis direction, the actual position W (xa, ya) of the coordinate indicator at time T is detected. Looking at the relationship between coordinates (xi, YT), TX=T
-Δt/2 ・Old...(11T,=
'r+Δt/2 ・Old... If (2), then XT = Xy VX ・Δt/2 ・・
...(3)YT-yT×,・Δt/2
...(4), and the second term of the above (31, (41) becomes the reading error of the X-axis and Y-axis. This reading error is
The larger Δt is, the faster the moving speed of the coordinate indicator V, ,V,
increases as the value increases. This reading error is called a reading error that depends on the moving speed of the coordinate indicator.

In this way, the method of sequentially scanning and detecting the induced voltages on each of the X-axis and Y-axis sense lines using one induced voltage detection circuit can reduce the scale and cost of the device, but There is a problem in that reading errors are caused depending on the moving speed of the device.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not give consideration to miniaturization and cost reduction of the device, and has the problem that the device is large and expensive. In addition, as a method for downsizing and lowering the cost of the device, the induced voltage of each sense line on the X-axis and Y-axis can be
When scanning sequentially using one induced voltage detection circuit, there is a problem in that reading errors depend on the moving speed of the coordinate indicator.

SUMMARY OF THE INVENTION An object of the present invention is to provide a coordinate reading device that can be made smaller in size and lower in price, and can reduce reading errors depending on the moving speed of a coordinate indicator.

[Means for solving problems]

The above object is to provide a coordinate reading device that can read the X and Y coordinates of an arbitrary point indicated by a coordinate indicator in a coordinate area having intersecting X and Y coordinate axes. The coordinate indicator includes an excitation winding that is excited by an alternating voltage supplied from a voltage generating circuit to generate an alternating magnetic field, and the coordinate indicator that generates an alternating magnetic field is moved along the X coordinate direction to induce The magnitude and polarity (in phase or opposite phase of the alternating magnetic field generated by the coordinate indicator) of the alternating induced voltage signal that is generated changes periodically (the length of one cycle is set to 2P).
) The fine position sense line placed in the coordinate area is
An X-coordinate fine-position sense line group formed by arranging a plurality of lines shifted by a predetermined width along the X-coordinate direction, and a Y-coordinate fine-position sense line group similarly formed along the Y-coordinate direction; The coordinate area is divided into a plurality of coarse areas along the X-coordinate direction with a width smaller than the length of one period (2P), and when the coordinate indicator that generates an alternating magnetic field moves along the X-coordinate direction. , a coarse position sense line group for the X coordinate consisting of coarse position sense lines placed in each coarse area so that the rough area where the indicator is located can be detected; A switching circuit connects the coordinate rough position sense line group and the sense line output of each of the sense line groups at a predetermined timing related to the alternating voltage supplied from the alternating voltage generating circuit to the excitation winding of the coordinate indicator. sequentially through
The switching order of the sense line output of each sense line group in the induced voltage detection circuit to be detected and the switching circuit is determined by the X (or Y) coordinate fine position sense line group, the Y (
Or fine position sense line group for X) coordinate, coarse position sense line group for X (or Y) coordinate, coarse position sense line group for Y (or This is achieved by providing a sense line scanning control circuit that causes the induced voltage detection circuit to detect the sense line outputs serially in the order in which the groups are prioritized.

(Function) The induced voltage in the fine position sense line changes periodically as the coordinate indicator moves along the detection coordinate axis, so the reading range in the detection coordinate axis direction is determined by the width of this repetition period (assumed to be 2P). By dividing the region and calling each divided region a periodic region, it is possible to detect the position within the periodic region (referred to as periodic position) based on the relative magnitude of the induced voltage of the fine position sense line group. .

Moreover, in which periodic region the coordinate indicator is located can be detected by detecting the rough position sense line with the maximum induced voltage and by the installation position thereof. Therefore, the position of the coordinate indicator is obtained by adding the above-mentioned periodic position X1 and the position Xc of the periodic region in which the coordinate indicator is located.

Here, the first. If the second coordinate axes are the X and Y axes, the sense line scanning control circuit is configured to control the X-axis peripheral fine position sense line group, the Y-axis peripheral position sense line group, the X-axis peripheral position sense line group, and the Y-axis peripheral position sense line group. Since the switching circuit is controlled to selectively scan in the order of the coarse position sense line group, the average sense time TX of the X-axis peripheral fine position sense line group and the average sense time T of the Y-axis peripheral position sense line group
The difference Δt from vs.

Compared to the selection scan based on the order of the Y-axis coarse position sense line group, n
o / (no 10 m.).

Here, no is the number of fine position sense lines for each coordinate axis.

mo is the rough position sense line number of each coordinate axis, usually m.

>no.

However, conversely, the difference Δt x between the average sense times TXs, TX, of the X-axis peripheral fine position sense line group and the coarse position sense line group
sc becomes (3no +mo)/(no +m0) times, and the difference Δt YSG between the average sense times T,..., TY of the Y-axis circumferential fine position sense line group and the coarse position sense line group
is (no + 3mo) / (no 10mo > times, and the difference between the periodic same position (also called fine position) detection time and the periodic area position (also called coarse position) detection time where the coordinate indicator is located increases. , when the coordinate indicator is moving, the possibility of error in coarse position detection increases. This is when the coordinate indicator is located.

Since the coarse position sense line group is laid so that the width Q of the region detected by the coarse position sense line that gives the maximum induced voltage (referred to as the coarse region) is smaller than the width 2P of the periodic region, the detected The coarse region spans the circumference w1'M region ASi, ASi, , which corresponds to or is adjacent to the only periodic region AS. In the latter case, since Q<2P, the periodic region AS.

ASi. Periodic same position X within the detected rough area of 1
The value of 1 does not take the same value, and the range of possible values is different.

Therefore, a threshold value is set in advance corresponding to the coarse position sense line that gives the maximum induced voltage, and this threshold value and the periodic position X
, the unique periodic region can be determined by comparing . As a result, the coordinate indicator moves during Δtsc, and even if an adjacent coarse region is detected with respect to the original coarse region at the average sense time T of the fine position sense line group, the moving distance between Δtsc is (2P -Q)/2 or less, a correct periodic region can be detected.

In this way, TXs and T7. The difference Δt5 can be made small, and the correct periodic region can also be detected by moving the coordinate indicator between At5c, so it is possible to reduce reading errors that depend on the moving speed of the coordinate indicator.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block configuration diagram of an embodiment of the present invention, where l is an excitation winding drive circuit, which is composed of an alternating voltage generation circuit 2 and an amplifier 3, and an excitation winding built in a coordinate indicator 4. line(
(not shown).

5.6.7 and 8 are flat plates made of insulating material and stacked on top of each other. A fine position sense line group 51 around the X-axis shown in FIG. 3 is laid on the flat plate 5, and a coarse position sense line group 61 around the X-axis shown in FIG. 4 is laid on the flat plate 6. On the flat plate 7,
A Y-axis circumferential fine position sense line group 71, which is obtained by rotating the laying pattern similar to the X-axis circumferential fine position sense line group 51 by 90', is placed on the flat plate 8 in the same manner as the X-axis circumferential coarse position sense line group 61. Y-axis peripheral fine position sense line group 8 with the laying pattern rotated by 90'
1 is installed.

Each sense line group 51, 61, 71 and 81 is connected to ten induced voltage detection circuits via a switching circuit 9.

Reference numeral 24 denotes a sense line scanning control circuit, the output of which is a sense line scanning control signal 241, is connected to the control terminal of the switching circuit via a launch circuit 25.

Further, 26 is a zero cross timing detection circuit whose input is connected to the output terminal of the alternating voltage generation circuit 2 and whose output is connected to the clock terminal of the launch circuit 25.

The induced voltage detection circuit 10 includes an amplifier 11. Filter 12.
Sample and hold circuit 13. It is composed of an A/D converter 14 and a peak timing detection circuit 16, and its output 10
1 is connected to the coordinate detection circuit 18 directly and via the polarity determination circuit 17.

The coordinate detection circuit 18 includes a fine position detection circuit 19. It is composed of a coarse position detection circuit 20 and an adder 21, and this adder 21
The output becomes the output 181 of the coordinate detection circuit 18.

23 is a control circuit, and control signals 231, 2, 32, 233, and 234 for controlling the operations of the sense line scanning control circuit 24, the induced voltage detection circuit IO, and the coordinate detection circuit 18 are connected to each circuit.

Further, the fine position detection circuit 19 includes, as shown in FIG. 2, a sense line data storage circuit 191.2 a signal conversion circuit 192. Normalization circuit 1931 Position conversion circuit 194, Maximum fine position sense line detection circuit 1951 Intra-period offset value calculation circuit 19
6 and an adder 197.

The coarse position detection circuit 20 includes a maximum value fine position sense line detection circuit 201, a cycle number determination circuit 202, and a cycle reference point position calculation circuit 203.

1, the excitation winding of the coordinate indicator 4 is excited by an excitation alternating voltage signal from the excitation winding drive circuit 1, and an alternating magnetic field is generated around the excitation winding.

When this coordinate indicator 4 is brought close to the flat plates 5 to 8, the sense line groups 51 and 61 laid on the flat plates 5 to 8 by an alternating magnetic field
．． An alternating induced voltage is induced in each sense line 71 and 81.

The switching circuit 9 is controlled by a sense line scanning control signal 251 that is output from the sense line scanning control circuit 24 and supplied via the launch circuit 25, and is controlled by the sense line scanning control signal 251 that is output from the sense line scanning control circuit 24 and supplied via the launch circuit 25, and switches between each sense line group 51, 61 .
In order to select one of the sense lines 71 and 81, only the corresponding switch (not shown) connected to each sense line is closed, and the alternating induced voltage of the selected sense line is It leads to the induced voltage detection circuit 10.

The present invention is characterized by the order of selection scanning of the sense lines (selecting each sense line in a similar order) and the timing of switching of the switching circuit 9, which will be described in detail later. As a result, the coordinate indicator 4, which is a problem in the prior art,
This reduces reading errors that depend on the moving speed of the object.

The induced voltage detection circuit 10 detects an induced voltage at a predetermined phase timing (positive peak timing) of an excitation alternating voltage signal of an alternating induced voltage signal induced in a selected sense line.

The polarity determination circuit 17 determines whether the phase of the alternating induced voltage signal of the selected sense line is in phase with the phase of the excitation alternating voltage signal, depending on whether the induced voltage obtained from the induced voltage detection circuit 10 is positive or negative. do.

The coordinate detection circuit 18 determines the coordinate position of the coordinate indicator 4 based on the induced voltage of each sense line and the polarity determination result.

To be more specific, the fine position detection circuit 19 constituting the coordinate detection circuit 18 detects the fine position based on the induced voltage and polarity determination result of each sense line of the fine position sense line group 51, and determines the coarse position. The detection circuit 20 detects the coarse position based on the induced voltage of each sense line of the coarse position sense line group 61 and the fine position obtained from the fine position detection circuit 19, and calculates the coordinate indicator 4 by adding both values. Determine the position in the X-axis direction. Similarly, fine position sense line group 71. Based on the induced voltage of each sense line of the coarse position sense line group 81 and the polarity determination result,
The position of the coordinate indicator 4 in the Y-axis direction is determined.

Since the method of determining the position of the coordinate indicator 4 in the X-axis direction and the Y-axis direction is the same, in the following explanation, only the method of determining the position in the X-axis direction and the operation will be explained.

The detailed configuration and operation of each component will be described below.

Laying Pattern 2 of Fine Position Sense Line Group FIG. 3 shows a laying pattern of fine position sense line group 51 in one embodiment of the present invention.

The fine position sense wire group 51 includes fine position sense wires S having loop-shaped portions spaced apart by a pinch P, and made of electric conductor wires connected so that the directions of current flowing in adjacent loop-shaped portions are opposite to each other. , , SZ, s3 and S4
It consists of four books. These four fine position sense lines are connected to a flat plate 5'' with a predetermined clearance width Z, here Z = P.
/ 4. = 7! They are laid by closing and shifting them by Z in parallel to the X axis.

One end of each fine position sense line SI"S4 is connected to the terminal TS
1 to T Sa to the switching circuit 9 .

Further, the other ends of each of the fine position sense lines 81 to S4 are connected to each other at points I (points I) shown in the figure, and adjacent inter-loop connections connecting adjacent loop-shaped portions of each fine position sense line from the connection points. It is led to terminals TSc arranged in the vicinity of terminals TS, -TS4 via return lines Sc made up of electrical conductor wires laid in parallel close to the parts.

The induced voltage of each fine position sense line S+''Sa is sent to the induced voltage detection circuit 10 via the switching circuit 9 based on the alternating induced voltage generated between the terminal TSo and each terminal TS, ~TS. detected.

Induction characteristics of fine position sense line FIG. 5 is a diagram for explaining the induction characteristics of one fine position sense line S.

FIG. 5(1) is an enlarged view of a part of the laying pattern of the fine position sense line group shown in FIG.

FIG. 5(2) shows a laying pattern of the fine position sense line S1 shown in FIG. 5(1). B and D not shown in the figure.

The position area of F is a loop-shaped part, and A, C, and E.

The position region of G is a connecting portion between adjacent loops. Point H is the connection point between the fine position sense line S1 and the return line Sc. Further, the arrows in FIGS. 5(2) and 5(3) indicate the return line S from the terminal TS via the connection point H.

It shows the direction of the current in the electrical conductor wire portion of each part when the current flows toward the terminal TS.

As can be seen from the figure, the direction of the current is clockwise in the loop-shaped part of the position area B, counterclockwise in the loop-shaped part of the adjacent position area D, and clockwise in the loop-shaped part of the adjacent position area F. becomes.

In this way, when adjacent loop-shaped portions are connected by the adjacent inter-loop coupling line as shown in FIG. 5(1) or 5(2), the directions of currents flowing in the adjacent loop-shaped portions become opposite to each other.

Here, the relationship and interaction between the return line Sc and the connecting portion between adjacent loops will be mentioned.

The electric conductor wires of the coupling portions between adjacent loops in the position areas A, C, E, and G and the return line Sc are arranged close to each other and parallel to each other. Further, as shown in FIG. 5(2), the directions of current flow in the connecting portion between adjacent loops and the return cotton Sc are opposite to each other.

Therefore, when the coordinate indicator 4 is located at point E6 in FIG. 5 (2), the electromotive force induced in the coupling portion between adjacent loops in the position area of E or the induced current accompanying this is e (s I
E), and let e(set) be the electromotive force induced in the return line SC in the position area of E or the induced current associated with it, then both electric conductor wires have the same length and are arranged close to each other in parallel. Since e (SIE) = 6 (SCE)
--(It becomes 51.

When looking at this between terminals TS and 'rsc, Figure 5 (2)
As shown by the arrows in the middle, the current flows from TS and TS2 are in opposite directions, so the electromotive force generated in both or the induced current that accompanies this will cancel each other out. Become. Therefore, the inter-adjacent loop coupling portions of the position areas A, C, E, and G and the portion of the return line Sc placed close to and parallel to these do not contribute to the induction characteristics, and are shown in FIG. 5 (3). Only the solid line portion contributes to the generation of an alternating induced voltage with respect to the alternating magnetic field created by the excitation winding built into the coordinate indicator 4. As a result, in the fine position sense line S1 shown in FIG. 5(2), only the electric conductor wire in the solid line portion shown in FIG. 5(3) contributes to the generation of alternating induced voltage, and the solid line portion is In the location area,
A clockwise loop of l-turn is formed, a counterclockwise loop of l-turn is formed in the D position area, and a clockwise loop of one turn is formed in the F position area.

This means that the one-turn loop line shown in Figure 5 (4) is
Loop lines S, ,S, in the position areas of ,D,F.

SF is placed, and the alternating induced voltage of each loop line is ``E+eD+
It is equivalent to adding eF. (Please note that the voltage of en has a different standard from "B+"F.) Figure 5 (5) shows this situation, where the horizontal axis shows the position of the coordinate indicator 4, and the vertical axis shows the position of the coordinate indicator 4. The axis shows the phase relationship between the magnitude of the alternating induced voltage and the excitation alternating voltage applied to the excitation winding.

eB + eD + eF in FIG. 5 (5) indicates the magnitude of the alternating induced voltage of the loop lines Sg, So, and Sv, and the thick solid line is the sum of these. Loop line S
Il+eF reaches its maximum value at the center of the loop of R and SF, and becomes smaller as it moves away from the center.

Although eD reaches its maximum value at the center of the loop line S, the phase of the alternating induced voltage is opposite to the phase at the center of the loop lines S, , S,.

The induction characteristics of each loop line are the same, but the only difference is the placement position of the loop, so the result of adding these is the maximum in phase at the center of the position area of B, as shown by the thick solid line, and the 0 point The induced voltage becomes zero at (the center point between the loop-shaped parts), the phase reverses, and reaches a maximum in the opposite phase at the center of the position area of D, the induced voltage becomes zero again at the R0 point, and the phase reverses again. It is maximum in phase at the center of the position region of F.

In this way, the induced voltage characteristic of the fine position sense line S has a repeating characteristic with a period of 2P, which is twice the arrangement pitch P of the loop-shaped portion.

As shown in Fig. 3 and Fig. 5 (1), the sense line 5l-34 is shifted in the X-axis direction by a width Z=P. Since the sense lines are laid staggered by /4=# (the loop width of the loop-shaped portion), the induced voltage characteristics of each sense line are as shown in FIG. 6 (2). FIG. 6(3) shows the induced voltage V (i) (magnitude of the alternating induced voltage) of each fine position sense line S, and does not include phase information. Also, Figure 6 (4)
indicates the maximum value of the induced voltage V (i) of each fine position sense line S, -S4 at each position, and the fine position sense line that gives that value is connected from point R, as shown in the figure. 31132 in order. S3. S4+ Sl.

S2. ···become that way. In addition, the phase of the alternating induced voltage of the fine position sense line that gives the maximum value has a period of 2P (with P widths in the same phase) as shown in Figure 6 (5) with respect to the phase of the excitation alternating voltage that drives the excitation winding. 2-width anti-phase) is repeated. In this way, the induction characteristic of the fine position sense line group is 2
It is repeated with a period of P.

Here, as shown in (6) of Fig. 6, the reading range in the direction of the detection coordinate axis is divided into regions with a width of 2P of the repetition period of the induced voltage characteristic, and each divided region is called a periodic region. , if the reference point of periodic area AS is point R1, then (4
), as shown in (5), the fine position sense lines 81 to S
4, by detecting the sense line number of the fine position sense line with the largest induced voltage and the polarity determination result of that sense line, the periodic area is divided into 8 small areas A, ~A8. , in which small area the coordinate indicator 4 is located (
It is possible to detect whether this is called an intra-period offset value.

Furthermore, the detailed position of the coordinate indicator 4 within the small area (this is referred to as the position within the small area) is determined by the relative position of the induced voltage of the fine position sense lines 81 to s4, as shown in (3) of FIG. It can be detected by its size.

By adding this intra-period offset value and the position within the small area, the position from the reference point of the periodic area (this is referred to as period self-position) can be detected, but the fine position sense lines 81 to S
Since the guidance characteristic of No. 4 is repeated with a periodic width of 2P, it is not known in which periodic region the coordinate indicator is located.

The sense lines for detecting this are the role of the coarse position sense line group.

Coarse position sense line group The coarse position sense line group 61 is for dividing the reading range in the direction of the detection coordinate axis into a coarse area having a width Q of less than the cycle width 2P of the induced voltage characteristic formed by the fine position sense line group 51 described above. This is a group of sense lines.

FIG. 4 shows a laying pattern of the coarse position sense line group 61 according to an embodiment of the present invention.

As shown in the figure, a plurality of coarse position sense lines G1 made of loop-shaped electrical conductor wires are shifted parallel to the detection coordinate axis by a width Z, =Q<2P, and laid on a flat plate 6. It consists of

Here, if the loop width of the loop shape of the rough position sense line is β, then in FIG. 4, ZG = 6Z < 2P = 8Z, Il
, and Z.

One end of each rough position sense line G is connected to a return line GC made of an electric conductor line at each of 81 points, and one end of the return line G is led to a terminal TGC. In addition, each rough position sense line G
The other end of , as shown in the figure, is led to a terminal TG disposed near the terminal TGc by an electric conductor wire laid parallel and close to the return line GC. Each terminal TG is a switching circuit 9
It is connected to the induced voltage detection circuit 10 via.

The characteristics of the induced voltage generated between the terminal TG of each coarse position sense line G1 and the terminal TGc of the return line Gc are similar to the relationship with the fine position sense line S and the return line Sc described above, and are close to the return line Gc. The induced voltage or the induced current generated in the return line corresponding to the coarse position sense line laid in parallel cancel each other out.
A loop line Q having a loop width l2z (=62) shown in the figure
, becomes equal to 1.

At this time, the characteristics of the induced voltage of each rough position sense line G are as shown in FIG. 7(2). The vertical axis indicates the magnitude of the amplitude of the alternating induced voltage, and in-phase/opposite phase indicates the phase relationship with the excitation alternating voltage.

Therefore, if the largest coarse position sense line G in the same phase is detected from the induced voltage value of each coarse position sense line, the coarse area AG divided by the coarse position sense line group 61 will be determined according to its installation position.
i (shown in (3) of FIG. 7), the rough area where the coordinate indicator 4 is located can be detected.

The width Q (=62) of the coarse area is the width 2P (= 8) of the periodic area.
Z), so the detected rough area is
A periodic area A corresponding to or adjacent to a unique periodic area AS
S1. It will span A S +++.

In the latter case, since Q<2P, the periodic area ASi
, AS+, , within the detected coarse region do not take the same value, but have different ranges of possible values. Therefore, by setting a threshold value in advance corresponding to the rough position sense line that gives the maximum induced voltage and comparing this threshold value with the period self-position, it is possible to determine a unique period region.

Thereby, the position of the coordinate indicator 4 can be determined by adding the periodic self-position to the position of the reference point R8 of the determined periodic area A S +.

The above shows the installation pattern of the fine position sense line group and the coarse position sense line group according to an embodiment of the present invention, and shows that the position of the coordinate indicator 4 can be determined based on the alternating induced voltage signal induced in each sense line. explained.

Next, (1) the sense line scanning control circuit 24 which defines the order (sequence) of selective scanning of the sense lines of the switching circuit 9 and the switching timing; Specific operations of the latch circuit 25 and zero-cross timing detection circuit 26, and (2) switching circuit 9
The specific operation of the induced voltage detection circuit 10 that detects the induced voltage from the alternating induced voltage signal induced in the sense line selected in (3) the induced voltage of each sense line detected by the induced voltage detection circuit 10. The specific operation of the coordinate detection circuit 18 that determines the position of the coordinate indicator 4 will be explained below.

Sense Line Selection Scanning Sequence and Switching Timing The sense line scanning control circuit 24 in FIG. do. Sense line code signal string to sense line scanning control signal 2
It is called 41. The sense line scanning control circuit 24 is composed of a cyclic counter 242 and a sense line code memory 243, as shown in FIG.

Here, coarse position sense line group 61.8 for X-axis circumference and Y-axis
The number of sense lines is 1 for each meter. (the value of m o increases in proportion to the coordinate reading range), and the total number of sense lines M. 2(
4+mo) (because the number of sense lines in the fine position sense line groups 51 and 71 for the X-axis circumference and Y-axis is 4 each), the cyclic counter 242 controls the control circuit 23 from O to (MO-1). It is a cyclic counter that counts and amplifies in synchronization with the timing signal 231 supplied from the source, and is immediately reset to 0 when it reaches Mo. The sense line code memory 243 is a memory that receives the output value of the cyclic counter 242 (input address) and stores the code signal of the sense line in a corresponding predetermined memory area.
M (read-only memory). here,
This sense line code memory 243 stores the cyclic counter 2
42, the total number of X-axis fine position sense lines I
+S)12+SX3. SX4. Y-axis peripheral fine position sense line SVl+ Svz+SY3+ SY4
+ Total number of X-axis circumferential coarse position sense lines +, GX2゜...,
G... , and Y-axis coarse position sense line G7. .

G7□,...,G7. . In order to respond in this order, M.

The code signals of the sense lines are stored in a predetermined memory area.

By storing the code signal of the sense line in this way, as shown in FIG. 9, the control circuit 2 of FIG. 9(1)
In response to the timing signal 231 from 3, the cyclic counter 242 counts up from 0 to (Mo 1), and the corresponding sense line code signal is as shown in FIG. 9 (2).
, as shown in (3), the X-axis fine position sense line and the Y-axis angular fine position sense line.

The X-axis coarse position sense line and the Y-axis coarse position sense line are output from the sense line code memory 243 in this order.

In addition, in FIG. 9, the number m of sense lines of the coarse position sense line groups for the X-axis circumference and the Y-axis is shown as four lines each.

This sense line code signal string 241 is supplied to the switching circuit 9 via the launch circuit 25. The switching circuit 9 is composed of a group of switches connected to each sense line and a decoder that decodes the sense line code signal, and as shown in FIG. 9 (4), switches the sense line corresponding to the sense line code signal. Decode the sense line code signal to select the corresponding switch (
(not shown) only.

As a result, the switching circuit 9 switches between the X-axis fine position sense line, the Y-axis angular fine position sense line, the X-axis coarse position sense line, and the Y-axis coarse position sense line, as shown in FIG. 9 (5). The alternating induced voltage signals of the selected sense lines are sequentially supplied to the induced voltage detection circuit 10.

Note that the sense line scanning control circuit 24 may be configured only with the above-described cyclic counter 242, and the decoder of the switching circuit 9 may be configured in the selected scan order of the sense lines as described above.

The sense line selection scanning sequence (the order of sense lines to be scanned) of the sense line scanning control circuit 24 has been described above, but the sense line code signal output from the sense line scanning control circuit 24 is is supplied to the switching circuit 9 at a predetermined timing.

This timing is controlled by the output signal 261 of the zero cross timing detection circuit 26, and the launch circuit 25+7)
Applied to the clock terminal. The zero cross timing detection circuit 26 is composed of a comparator as shown in FIG. 8, and one input is the output signal of the alternating voltage generation circuit 2.
The other is grounded. Therefore, the output signal of the zero-crossing timing detection circuit 26 is a signal whose logic level changes from 1.0 at the zero-crossing timing of the excitation alternating voltage signal ((1) in FIG. 10), as shown in (2) in FIG. becomes.

The launch circuit 25 takes in the input signal (sense line code signal) at the rising edge of this signal (261) and outputs it, so the output signal of the launch circuit 25 is equal to the excitation alternating voltage as shown in Figure 1O (3). It will switch at the zero cross timing of the signal.

As mentioned above, the alternating induced voltage signal induced in each sense line is an alternating voltage with the same phase or the opposite phase with respect to the excitation alternating voltage signal, so at the zero cross timing of the excitation alternating voltage signal, the alternating The induced voltage is O. Therefore, the switching circuit 9 operates to switch the sense lines when the alternating induced voltage of each sense line is 0, so the output signal of the switching circuit 9 becomes as shown in FIG. , the discontinuity caused by the difference in induced voltage of each sense line is eliminated.

Induced voltage detection circuit The induced voltage detection circuit 1o in FIG. The induced voltage v (i) at the timing of the peak value is detected. For this purpose, v(i) is first amplified by a predetermined amount using an amplifier 11, unnecessary noise components are removed using a filter 12, and then the signal is input to a sample and hold circuit 13.

The sample/hold circuit 13 has its sample/hold operation controlled by the output signal of the peak timing detection circuit 16.

FIG. 11 shows the configuration of the peak timing detection circuit 16. The peak timing detection circuit 16 includes a mouth-bass filter 161. Comparator 162 and D-type flip-flop 16
It consists of 3.

The number f C of corners 11 of the low-pass filter 161 is the frequency f of the excitation alternating voltage signal. Since it is set sufficiently smaller, the output of the low-pass filter 161 is a signal (Fig. 10 (4)) whose phase is shifted by 906 with respect to the excitation alternating voltage signal (Fig. 10 (1)). . Comparator 1
62 compares this 90' shifted signal with a predetermined value (zero), and outputs a rectangular wave that rises at the timing of the positive peak value of the excitation alternating voltage signal, as shown in FIG. 10 (5). , this is C1 of the D-type flip-flop 163.
ock terminal.

A sample-and-hold control signal 232 (FIG. 10 (6)) supplied at a predetermined timing from the control circuit 23 is input to the Data input terminal of the D-type flip-flop 163, and is sampled at the rising edge of the signal at the C1ock terminal. Therefore, as shown in FIG. 10 (7), the Q output terminal of the D-type flip-flop 163 outputs logic 1.0, samples at logic 1, and holds at logic 0 at the timing of the positive peak value of the excitation alternating voltage signal. ) is switched.

Since the signal of this Q output terminal specifically controls the sample and hold circuit 13, the sample and hold circuit 13
The value of the alternating induced voltage (induced voltage) of each sense line at the timing of the positive peak value of the excitation alternating voltage signal is held. Sample bold circuit 1 for the input signal of sample bold circuit 13 shown in FIG. 10 (8)
The output signal of No. 3 is shown in FIG. 10 (9).

The Hall F value of the sample and hold circuit 13 takes a positive value if the alternating induced voltage of the sense line is in phase with the excitation alternating voltage signal, and takes a negative value if the alternating induced voltage of the sense line is in phase with the excitation alternating voltage signal. A/D converter 1
4 converts the value held by the sample hold circuit 13 into a digital value and outputs it. This becomes the output of the induced voltage detection circuit 10.

The polarity determination circuit 17 includes a comparator 1 as shown in FIG.
70, it is determined whether the alternating induced voltage is in phase with the excitation alternating voltage signal by comparing whether the output of the induced voltage detection circuit IO is larger than a threshold value (zero in this case).

The induced voltage of each sense line detected in this way and the polarity determination result of the polarity determination circuit 17 are supplied to a fine position detection circuit 19 and a coarse position detection circuit 20 that constitute the coordinate detection circuit 18 .

Since the X-axis and Y-axis coordinate detection operations of these circuits are the same, the following description will focus on the X-axis coordinate detection operation.

As shown in FIG. 2, the fine position detection circuit 19 in FIG. Induced voltage V on position sense lines S+, S2, Sl and S4
(S +), V (S 2), V (S:+)
and v (S 4.) and polarity determination results P (Sl), P
(S2).

P(Sl) and P(S,) are temporarily stored in the sense line data storage circuit 191.

Specifically, the induced voltage is stored in the voltage value memory 1911 and the polarity determination result is stored in the polarity memory 1912 in predetermined areas corresponding to sense line numbers 1 to 4 of the micro-level device sense lines. The induced voltages and polarity determination results of these fine position sense lines are as shown in FIGS. 6(2) and (5) with respect to the position of the coordinate indicator 4.

Therefore, first, in the maximum value fine position sense line detection circuit 195, among the induced voltages V (S +) to v (S 4.),
Detect the maximum fine position sense line (this is referred to as the maximum fine position sense line), and detect its sense line number n (this is referred to as the maximum fine position sense line number) and the corresponding polarity determination result. Output P(S,).

The intra-cycle offset value calculation circuit 196 calculates, based on the maximum fine position sense line number n and the polarity determination result P (Sfi),
The offset value from the reference point R8 of the periodic area of the small area where the coordinate indicator 4 is located (the area A1 to A8 obtained by dividing the periodic area shown in (6) in FIG. X0FF is calculated using the following formula.

(6) However, Z is the shift width of the fine position sense line and corresponds to the width of the small area.

Offset value X within this cycle. F' is supplied to one input of the adder 197.

The detailed position within the small area (position within the small area ΔX) is determined by the two-signal conversion circuit 192. Normalization circuit 193 and position conversion circuit 19
4 is detected as follows.

First, in the two-signal converting circuit 192, the maximum value fine position sense line number n and the induced voltages V(S, ) to V (
S 4. ), the two composite voltages Vs shown in the following formula,
Calculate Vc.

Vs-I V(S, l) l +l lsn++) l
-l ■(sn+z) l-l V(sn-+) l
・・・・・・(7) Vc-11
3fi) Ills, 1) l-IV(Sn, 2) 10l
V(S11-+) l ・Old・
・(8) However, Ial is the absolute value of a. V(St) is the induced voltage of the fine position sense line S. When n-1=O, 1=4 When n+j>4, i=n+j -4 For example, n=3
When , V(Sll), V[S,,l).

V(S, , ri and V(Sfi-+) correspond to the induced voltages of fine position sense lines S3+S4.S1 and S2.

In other words, as shown in Figure 12 (1) and (2),
V[S□I) is the induced voltage of the fine position sense line which has a loop shape part on the right side of the loop shape part of the maximum value fine position sense line Sn, and V(S□I) is the induced voltage of the fine position sense line which has a loop shape part on the left side of the loop shape part of the maximum value fine position sense line Sn. The induced voltage of the fine position sense line with
z) corresponds to the induced voltage of the fine position sense line having a loop-shaped portion farthest from the loop-shaped portion of the maximum value fine position sense line S, , among the four fine position sense lines. Of course, ■(Sfi) is the maximum fine position sense line S
Corresponds to the induced voltage of 7.

The composite voltage VS, Vc according to the above equation is within the small head area (area from point 80 to point B2 in the figure) as shown in Figure 12 (3).
, one becomes a composite voltage that monotonically increases and the other monotonically decreases, and both values become equal at the center of the small region (point B in the figure).

The normalization circuit 193 generates the composite voltage (■) of both of them.

The relative magnitude ρ (normalized value) of and V is calculated, for example, by the following formula.

■.

J−璽−V(” −=−(9)゛This normalized value ρ is a value that increases monotonically within the small area, as shown in FIG. 12 (4). Therefore, the value of this ρ teeth,
Since this corresponds to the only position within the small area, the position of the coordinate indicator 4 within the small area can be known by detecting the (direction) of ρ.

The position conversion circuit 194 inputs this ρ and outputs the corresponding position ΔX in the small area, and is constituted by a memory that stores the position ΔX in the small area corresponding to each value of ρ. At this time, if the relationship between the actual position ΔX in the small area of the coordinate indicator 4 and ρ is ρ−g(ΔX), the position conversion circuit 194
The function ΔX-7(ρ) is ΔX-7(ρ) -g (g (ΔX))-ΔX...
...converts ρ and ΔX that satisfy ao.

The position ΔX within the small area thus obtained is inputted to the other side of the adder 197 to obtain the intra-period offset value X. It is added to FF to output periodic self-position X+.

FIG. 13 shows the offset value X within one period of the small region within two periods of the periodic region. The relationship between FF + position ΔX in the capitellar area and period self-position X1 is summarized.

■Creation I　■Shiroro The coarse position detection circuit 20 in FIG.
The induced voltage and polarity determination results of the rough position sense line (the installation pattern is shown in Fig. 4) obtained sequentially from 7, and
Period self-position X1 obtained from the above-mentioned fine position detection circuit 19
Based on this, it is detected in which periodic region the coordinate indicator is located, and the position of the reference point R8 of the detected periodic region As is output.

Since the induced voltage of the coarse position sense line G is as shown in FIG.
1 is the polarity determination result P(G,
) indicates the same phase (positive) and the coarse position sense line G□ with the maximum induced voltage V (Gi) is detected, and the corresponding sense line number m is output.

The sense line number m of this maximum value rough position sense line Sm corresponds to the rough area AG where the coordinate indicator 4 is located, as shown in (2) and (3) of FIG.

The cycle number determination circuit 202 detects the maximum value rough position sense line Sm
The cycle number N of the cycle area ASH in which the coordinate indicator 4 is located is detected using the sense line number m and the above-mentioned cycle inner position WX1.

FIG. 14 shows the relationship between the periodic areas AS□, As, .

In this embodiment, the width of the periodic region 2P=82. Coarse area width Q
= 6Z (equal to the shift width Zc of the coarse position sense line), the positional relationship between the periodic area and the coarse area is 24. It is repeated with Z as the period. Further, in this embodiment, the boundaries between the two areas are shifted so that they do not overlap in position.

Since Q<2P, one coarse region corresponds to only one periodic region as shown in the figure, or corresponds to two adjacent periodic regions.
It spans two periodic regions.

The following Table 1 shows the relationship between the coarse area, the corresponding periodic area, and the periodic self-position X1 based on FIG. 14. In addition, xa + Xb in Table 1 and FIG.
+Xc and x4 indicate the value of the periodic self-position X1 at the boundary point of the coarse area,
-5,5z, Xc = 3.52 and xd = 1.5
It is Z.

In this way, even if a coarse region straddles two adjacent periodic regions, the range of values that the periodic self-position X1 can take within the detected coarse region of both periodic regions is different. A unique periodic region can be determined by taking .

In other words, as shown in the right part of Table 1, each coarse area AGJ~A
Corresponding to G, , the threshold value TH, ~TH.

is set in advance, and the only periodic area can be determined depending on whether or not the in-period position X1 is larger than the threshold corresponding to the detected coarse area.

Table 1 In addition, the threshold value TH, ~TH, is THI-(xa + Xb) /2 -...
(11) THE = (xb + xc) /2
・−・−(12)TH3−(xc + xa)
/ 2 ・”-(13)TH4-(xa +
X, 8 Z ) / 2 (14) may be used. By setting the threshold value in this way, the rough detection area of the rough position sense line is expanded (
It is possible to detect the correct periodic region even if the periodic region (shaded area in the figure) is detected.

Based on the above principle, 1. The cycle number determination circuit 20 is
Periodic area As where the coordinate indicator 4 is located.

Detect the period number N of .

FIG. 15 shows a specific configuration of the cycle number determination circuit 202 in FIG. 2. 2020 is a threshold memory, 2021 is a comparator, and 2022 is a cycle number memory.

The threshold value memory 2020 stores the above-mentioned cycle number determination threshold value T.
H, to T H4 are stored in correspondence with the number of the coarse position sense line, that is, the number of the coarse area.

Further, the period number memory 2022 stores periodic area numbers corresponding to coarse area numbers (coarse position sense line numbers) as shown in Table 1.

When the maximum value coarse position sense line number m is input from the maximum value coarse position sense line detection circuit 201, the threshold value memory 202
0 takes m as an input address and outputs the corresponding threshold value TH. The comparator 2021 compares this threshold value TH with the intra-cycle position X1 supplied from the fine position detection circuit 19, and outputs the comparison result.

The cycle number memory outputs the number N of the corresponding cycle area using the comparison result and the maximum value rough position sense line number m as input addresses.

The cycle reference point position calculation circuit 203 in FIG. Calculate.

The periodic region is from the coordinate axis origin to AS,, AS2,...

If they are arranged in the order of ASN, the width of the periodic region is 2P=82, so Xc is:XC=2P・(N-1)...
(15).

This X is outputted as the output value of the coarse position detection circuit 20, and added to the intra-cycle position X obtained from the fine position detection circuit 19 by the adder 21.

This addition result (xc −1−X2) is the coordinate detection circuit 1
It is output as an output value of 8.

Other W ■ The sense line scanning control circuit 24 described above. Polarity determination circuit 17
, the coordinate detection circuit 18 and the control circuit 23 can be replaced by an arithmetic control section 3o as shown in FIG.

This arithmetic control unit 30 includes interface circuits 31, 34,
It is composed of a microprocessor 32 and a memory 33, and a program that defines the operation of the microprocessor 32 is stored in the memory 33. This program includes the sense line scanning control circuit 24, polarity determination circuit 17. Any system may be used as long as the operations of the coordinate detection circuit 18 and the control circuit 23 are executed sequentially. This allows the device to be further miniaturized.

In addition, the coarse position detection circuit 20 is provided with an X-axis circumference and Y-axis circumference maximum value coarse position sense line number memory, and once the maximum value coarse position sense line G1 is detected by the induced voltage of the combined rough position sense line, the The line number m is stored in the above memory, and from the next time onwards, the maximum value of coarse position sense is determined from the induced voltage of the three sense lines: coarse position sense line G and the coarse position sense lines on both sides of it, G+*+I+G, . By configuring the sense line scanning control circuit to detect lines, the selection scanning time of the coarse position sense line group can be shortened. This is called a coarse position sense line limited selection scanning method.

17 to 22 show the general flow of a program that defines the operation of the arithmetic control unit 30 of the other embodiment shown in FIG. 16, specifically, the operation of the microprocessor 32. Since the detailed operations of each processing routine in the flow have been described in the above-mentioned embodiments, the overall flow will be explained here, as well as the processing procedure of the above-mentioned coarse position sense line limited scanning method.

In addition, in FIGS. 17 to 22, processing routines that perform the same processing as the components on the above-mentioned physical side (FIGS. 1 and 2) are indicated by the same numbers, and to avoid confusion, An S is added after the number.

FIG. 17 shows the general flow of the microprocessor 32. Sense line scanning control and induced voltage capture processing 4
0 is the sense line scanning control circuit 24 and the induced voltage detection circuit 10
This processing corresponds to the control circuit 23 that controls the operation of the control circuit 23.

17S is a process corresponding to the polarity determination circuit 17, 41.42
corresponds to the coordinate detection circuit 18, which is a process of detecting the X-axis and Y-axis coordinates based on the detected induced voltage of the sense line.

A formatting process 43 converts the X and Y coordinate values into a predetermined format, and outputs coordinate data at 44. The microprocessor 32 is 40, 173, 41 in FIG.
, 42, 43, and 44 are repeated at a predetermined period (sampling period).

FIG. 18 is a flowchart of the sense line scanning control and induced voltage capture processing 40.

The determination loops 501 and 505 use the sense line code signal cxx(
+).

The induced voltage detection circuit 1 sequentially outputs i = 1 to 4 and detects the induced voltage of the sense line selected by the switching circuit 9.
This routine stores the induced voltage obtained by controlling the operation of 0 in a predetermined memory area 5X(i)3i=1 to 4 corresponding to the sense line.

Specifically, in 501, the sense line number i = 1, and 5
The X fine position sense line code C3x(i) is output at 02, the detection operation of the induced voltage detection circuit 10 is controlled at 400, and the induced voltage V obtained at 503 is stored in the memory VSx(i).
Store in. Then, in step 504, i=i+1, and 50
In step 5, it is determined whether i>4 or not, and the above processes of steps 502, 400, 503 and 504 are repeated until YES.

The determination loops 506 and 510 are a selection scan and induced voltage acquisition processing routine for the Y-axis circumferential fine position sense lines sy+ to sy4, and the induced voltage of each sense line is S y (i
) + i= stored in 1 to 4. The operation of this processing routine is the same as that for the X-axis fine position sense line described above.

Similarly, the determination loop 519 is based on the X-axis peripheral rough position sense line G
X1~GX+a. The selection scanning and induced voltage acquisition processing routine 523 is the selection scanning and induced voltage acquisition processing routine for the Y-axis circumferential coarse position sense line Gv+"Gv+no.

However, the selective scanning and induced voltage acquisition processing routines for these coarse position sense lines differ from those for fine position sense lines in that they do not necessarily selectively scan all sense lines, but rather limit the number of sense lines to be selectively scanned, and The point is that is variable for each sampling period.

Processes 511 to 515 perform this control. At 511, it is determined whether G11lSet FLAG is 1 or not. This G11lSet FLAG detects the maximum coarse position sense line number m (mX for the X axis and m7 for the Y axis) in the coarse position detection processing 20S described later, and corresponds this to the coordinate axis. When stored in the predetermined memory area mX, my, the cent is 1.

Therefore, when G and Set FLAG are 0 (set to O in the initial cent), the sense Line number initialization 'X+'Y is set to 1, and end value 'X11+' Ya is set to mo. mo is the number of coarse position sense lines.

Also, when Cll5et FLAG is 1, the maximum rough position sense line number rr3 has already been detected in the previous coordinate detection.
Since g and my have been detected, the range of selective scanning of the coarse position sense line this time is limited to only the vicinity of mX and my.

Therefore, in step 512, the initial value IX of the X-axis circumferential coarse position sense line number is set to (mx 1), and the end value IXa is set to (mX+1).
). Similarly, in step 513, the Y-axis circumferential rough position sense line number initial value 17 is set to (mV-1), and the end value is 17.
is set to (mV-1).

FIG. 19 shows the flow of the induced voltage detection circuit control process 400, and the operation timing corresponds to the timing diagram shown in FIG. 1θ.

The rising of the S-H control signal, waiting for a predetermined time, and falling of the S-H control signal of 401, 402, and 403 correspond to the S-H control signal 232 of FIG. 10 (6). and 40
4, it is detected whether the Q output of the flip-flop 163, that is, the control signal of the sample-and-hold circuit 13 is in a hold state, and if not, it waits until it becomes a hold state. Then, in step 405, the A/D converter is activated, and in step 406, a signal (EO
C) is detected, and in step 407, the A/D converted induced voltage (■) of the sense line is taken in.

FIG. 20 is a flowchart of the X and Y axis coordinate detection processing 41°42. 19S, 203, and 213 are fine position detection circuits 19. This corresponds to the operations of the coarse position detection circuit 20 and adder 21.

FIG. 21 is a flowchart of the fine position detection process 19S. 1
953, 196S, 192S, 193S.

194S and 197S are the maximum value fine position sense line detection circuit 1951 and the intra-period offset value calculation circuit 19, respectively.
6.2 Signaling circuit 192. Normalization circuit 1939 corresponds to the operations of position conversion circuit 194 and adder 197.

FIG. 22 is a flowchart of the rough position detection process 20S. 20
13, 202S, and 203S correspond to the operations of the maximum value coarse position sense line detection circuit 2011, the cycle number determination circuit 202, and the cycle reference point position calculation circuit 203, respectively.

The maximum value coarse position sense line number m obtained in the maximum value coarse position sense line detection process 201S is stored in the memory area m)H in 602 if the detected sense line is around the X axis in 601.
If it is for an axis, it is stored in the memory area my in 603. Then, in 604, GIISet FLAG is set to 1.

The following is a description of the reading error that depends on the moving speed of the coordinate indicator 4 in this embodiment.

It is assumed that the coordinate indicator 4 is moving at a speed V in the X-axis direction and a speed Vy in the Y-axis direction. At this time, let the actual position of the coordinate indicator 4 at time T be (XTI yT), XT = XI(T) 1XC(T) --
-----(16)yv =y+(T) yc(T)
−・・・・・・(17) However, x+(T),
y+(T) is the actual periodic self-position of the coordinate indicator at time T, and xc(T) and yc(T) are the reference point positions of the periodic region where the actual coordinate indicator is located at time T.

Also, for convenience of explanation, in this embodiment, the periodic self-position X1 is
Average sense time TX of fine position sense line group.

It is assumed that the periodic self-position of the coordinate indicator 4 at is detected. (Actually, it differs slightly because the coordinate indicator moves every moment.) Similarly, the average sense time of the coarse position sense line group is 1"XG
It is assumed that the reference point position of the periodic region where the coordinate indicator is located in is output as Xc. The same applies to the Y-axis direction.

In this embodiment, as shown in FIG. 9, the X-axis fine position sense line group, the Y-axis circumferential fine position sense line group, the X-axis circumferential coarse position sense line group, and the Y-axis circumferential coarse position sense line group are arranged in this order. Since the induced voltage of each sense line is detected (sensed), the average sensing time of each sense line group is T
s, T y s, T X a and TYG. Here, Δt s = T vs T xs.

Δj xsc −Txc ”r,,, Δj YS
Let G -Tyc Tys, and the relationship between T and TX, ,T, is Txs-T-Δts/2...
...(18) T vs - T + Δt, /2
......(19), then the periodic self-position X, , Y, obtained by this example is XI-xT-VX ・Δt,/2...(20)
Y, = yT-VV ・Δt s / 2 −- (
21), the second term in the above equation is the periodic self-position reading error, which is proportional to the moving speed V, , Va, and
Δ1. is proportional to. However, in the sense line selection scanning sequence of this embodiment, in order to minimize this Δt3 in the selection scanning sequence of four sense line groups, the X-axis fine position sense line group and the Y-axis peripheral fine position sense line group are For example, as a selection device sequence for another sense line group, select the X-axis fine position sense line group, the X-axis peripheral coarse position sense line group, the Y-axis peripheral fine position sense line group, and the Y-axis peripheral position sense line group. Compared to the conventional method that senses in the order of coarse position sense line group, Δ1s
is reduced to n(, / (no + mO). However, no is the number of sense lines of the fine position sense line group for each axis, which is 4, and mo is the sense line number of the coarse position sense line group for each axis. It is the number of lines.

Therefore, this embodiment can reduce the periodic self-position reading error to n 6 /(n 6 + mo) compared to the conventional method. The value of mo is usually mo > no and increases in proportion to the coordinate reading range.

In addition, in order to reduce the reading error to only the periodic self-position reading error, it is necessary to It is necessary to correctly detect the periodic region in which the
From Tys, ΔtXSG+ Δt YSG, respectively
Later.

This Δt xsc is (3nQ+rn
o ) / (n o + rno ) times, Δt
YSG increases by (no+3mo)/(no+mo) times. This Δt8.6. If the movement of the coordinate indicator in Δt YSG is not shown in FIG. 14 and is within each coarse area, the correct periodic area can be detected. This ΔtXSG
The possibility of false detection in the periodic region increases with an increase in ΔtXSG+Δt75. This is when the coordinate indicator moves across the boundary of the coarse area shown in FIG. 14(3).

For example, in FIG. 14, the coordinate indicator 4 at TX
is within the periodic area AS and within the coarse area AG, the detection period self-position X is located at a position below T H2, and Δt x
If it moves into the coarse area AGj, after sc, the coarse position detection circuit 20 compares the threshold value TH2 of ΔGJ,l with X, and if Xl is greater than 'rH2, the periodic area As,
If it is smaller, the periodic area AS is detected and output, and since XI<TH2 is set here, the periodic area AS is incorrect. 1 will be output, resulting in a reading error of about 82.

However, the coordinate indicator 4 is within the periodic area ASl and in the coarse area A.
G, Xl is located at a position higher than TH2 (first
4 (shaded area on the left side of the coarse area AG'J+, including the shaded area in Figure (4)) If the area moves into the coarse area A Gj+1 after Δt can be detected.

The same can be said for the boundary portions of each coarse area, and if the movement of the coordinate indicator at ΔtXSG+ΔtYSG is within the width of the shaded area in FIG. It is possible.

Also, the width of this shaded area corresponds to (2P-Q)/2, and Q
It is possible to enlarge the periodic region by making it small, and to reduce erroneous detection of periodic regions.

In addition, as shown in FIG. 10, this embodiment switches the sense lines at the zero-crossing timing of the excitation alternating voltage number, thereby preventing the switching error due to the difference in induced voltage of each sense line due to the switching of the sense lines. There is no continuity,
Amplifier 11 constituting the induced voltage detection circuit IO. It is possible to eliminate the transient response time due to discontinuity caused by switching of the sense lines in the filter 12, thereby making it possible to sense each sense line at a higher speed. By this speeding up, the above-mentioned ΔtS+ Δt xsc and Δt
Since t7 and t6 can be made smaller, it is possible to further reduce intra-period position reading errors and erroneous detection of periodic regions.

In addition, by using the coarse position sense line limited difference method described above, Δj
XsG+Δt vsG can be further reduced to 3/m, and erroneous detection in the periodic region can be further reduced. Furthermore, the reading speed can be increased.

〔Effect of the invention〕

As explained above, according to the present invention, the X-axis angle.

Conventionally, the position of the coordinate indicator is determined based on the induced voltage of each sense line obtained by sequentially scanning each Y-axis sense line with one induced voltage detection circuit, and each sense line is sequentially scanned. Compared to the conventional method, the reading error depending on the moving speed of the coordinate indicator can be reduced to 4/(4+m0). mo is a value that increases in proportion to the coordinate reading range and is usually 4.
That's all.

Therefore, it is possible to reduce the size and cost of the device, and to provide a coordinate reading device with small coordinate reading errors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the coordinate detection circuit in FIG. 1, and FIGS. 3 and 4 show the sense line laying pattern. The explanatory diagrams, FIG. 5, and FIG. 6 are characteristic diagrams showing the induced voltage characteristics of the sense line in FIG. 3, respectively. FIG. 7 is a characteristic diagram showing the induced voltage characteristics of the sense line in FIG. 4, and FIG. FIG. 9 is a block diagram showing the configuration of the sense line scanning control circuit in FIG. 1, FIG. 9 is a timing diagram showing the operation timing of the sense line scanning control circuit and switching circuit in FIG. 1, and FIG. 10 is a block diagram showing the induced voltage in FIG. 1. A timing diagram showing the operation timing of the detection circuit,
11 is a block diagram showing the configuration of the peak timing detection circuit shown in FIG. 1, FIGS. 12 and 13 are explanatory diagrams showing the operating method of the fine position detection circuit shown in FIG. 1, and FIG. Explanatory diagram showing the operating method of the coarse position detection circuit shown in Fig. 1.
5 is a block diagram showing the structure of the cycle number determination circuit shown in FIG. 2, FIG. 16 is a block diagram showing the overall structure of another embodiment of the present invention, and FIGS. 17 to 22 are the same as those shown in FIG. A flowchart showing an example of the operation of the microprocessor, and FIG. 23 is an explanatory diagram showing a rough operating method of the electromagnetic induction type coordinate reading device. Explanation of symbols ■...Excitation winding drive circuit, 4...Coordinate indicator, 5~
8... Flat plate, 51.71... Fine position sense line group, 6
1゜81...Rough position sense line group, 9...Switching circuit,
DESCRIPTION OF SYMBOLS 10... Induced voltage detection circuit, 24... Sense line scanning control circuit, 25... Latch circuit, 26... Zero cross timing detection circuit, 17... Polarity determination circuit, 18
. . . Coordinate detection circuit, 19 . . . Fine position detection circuit, 20
... Rough position detection circuit, 30 ... Arithmetic control section, 32.
...Microprocessor, 33...Memory Agent Patent Attorney Akio NamikiFigure 3Figure 4Figure 7Figure 8Figure 17Figure 18Figure 5TART 51
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Claims (1)

[Scope of Claims] 1. Coordinates from which the X and Y coordinates of an arbitrary point can be read when an arbitrary point is indicated by a coordinate indicator in a coordinate area having intersecting X and Y coordinate axes. In the reading device, the coordinate indicator includes an excitation winding that is excited by an alternating voltage supplied from an alternating voltage generating circuit to generate an alternating magnetic field; The magnitude and polarity (in phase or opposite phase of the alternating magnetic field generated by the coordinate indicator) of the induced alternating voltage signal change periodically (the length of one cycle is set to 2P).
) The fine position sense line placed in the coordinate area is
A group of fine position sense lines for the X coordinate formed by arranging a plurality of lines shifted by a predetermined width along the X coordinate direction, and a group of fine position sense lines for the Y coordinate formed similarly along the Y coordinate direction, The coordinate area is divided into a plurality of coarse areas along the X coordinate direction with a width smaller than the length of one period (2P), and the coordinate area is divided into a plurality of coarse areas along the X coordinate direction of the coordinate indicator that generates an alternating magnetic field. A coarse position sense line group for the X coordinate consisting of coarse position sense lines placed in each rough area so that the rough area where the indicator is located can be detected during movement; and a group of coarse position sense lines for the Y coordinate, and a sense line output of each of the sense line groups at a predetermined timing related to the alternating voltage supplied from the alternating voltage generating circuit to the excitation winding of the coordinate indicator. sequentially through the circuit,
The switching order of the sense line output of each sense line group in the induced voltage detection circuit to be detected and the switching circuit is determined by the X (or Y) coordinate fine position sense line group, the Y (
Or fine position sense line group for X) coordinate, coarse position sense line group for X (or Y) coordinate, coarse position sense line group for Y (or X) coordinate, etc. a sense line scanning control circuit that causes the induced voltage detection circuit to serially detect the sense line outputs in the order in which they are prioritized; A coordinate reading device characterized by determining and reading. 2. The coordinate reading device according to claim 1, further comprising a zero-cross timing detection circuit for detecting the zero-cross timing of the alternating voltage supplied from the alternating voltage generating circuit; A coordinate reading device characterized in that the switching circuit switches the sense line output. 3. In the coordinate reading device according to claim 1 or 2, the coarse position sense line receives the output from the coarse position sense line group and has a maximum magnitude due to the induced voltage as the output. a maximum value coarse position sense line detection circuit that detects the sense line number of the first maximum value coarse position sense line detected from the X coordinate coarse position sense line group using the maximum value coarse position sense line detection circuit; a first storage means for storing a sense line number m1; and a second maximum value coarse position sense line detected from the Y coordinate coarse position sense line group using the maximum value coarse position sense line detection circuit. a second storage means for storing a number m2 of X (or Y);
Coordinate fine position sense line group, Y (or X) coordinate fine position sense line group, first maximum value coarse position sense line number m1 stored in the first storage means and adjacent coarse position sense line X-coordinate coarse position sense lines numbered (m1-1) and (m1+1), the second maximum value coarse position sense line number m2 stored in the second storage means, and the adjacent coarse position sense line number ( A coordinate reading device characterized in that the induced voltage detection circuit serially detects the sense line output by switching a switching circuit in the order of Y-coordinate rough position sense lines m2-1) and (m2+1). 4. In the coordinate reading device according to any one of claims 1 to 3, the fine position sense line group includes a plurality of loop-shaped portions arranged at intervals of a pitch P. A fine position sense line consisting of conductive wires connected so that the directions of current flowing in adjacent loop-shaped portions are opposite to each other is connected to a P/4 line parallel to the coordinate axis direction on a flat plate forming a coordinate area. A coordinate reading device comprising four fine position sense lines arranged at intervals of . 5. In the coordinate reading device according to any one of claims 1 to 4, the coarse position sense line group includes a coarse position sense line consisting of a loop-shaped conducting wire. A coordinate reading device comprising a plurality of coarse position sense lines arranged parallel to each other along a coordinate axis direction on a flat plate forming a coordinate area and shifted by a distance equal to or less than twice the pitch P.