JPS62278626A - coordinate reading device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention applies an alternating magnetic field generated from a coordinate indicator to a sense line laid on a flat plate, and induces it in the sense line. The present invention relates to an automatic coordinate reading device that determines the position of a coordinate indicator by detecting the magnitude of an alternating induced voltage.

[Conventional technology]

In the conventional device, as described in Japanese Patent Publication No. 57-31188, a large number of loop-shaped sense wires are laid adjacent to each other on a flat plate, and the magnitude of the alternating induced voltage induced in each sense wire is equal to or smaller than the induced voltage. ) is detected.

The position of the coordinate indicator is determined by the ratio of the maximum value of these values to a signal value of an arbitrary order of magnitude among the induced voltages of the sense line located in the vicinity of the sense line giving the maximum value.

This will be referred to as the first conventional device.

In addition, as described in Japanese Patent Publication No. 53-34855, another conventional device has two senses @Is and lc which are arranged in a rectangular wave shape with a pitch P and are shifted by F/4 from each other on a flat plate. Due to the phase relationship between the composite voltage signal of the alternating induced voltages laid and induced in the two sense lines and the excitation alternating voltage signal that excites the excitation winding built in the coordinate indicator, it is possible to A loop-shaped electrical conductor wire (hereinafter referred to as a coarse position sense line) is obtained by obtaining the position information Po of the coordinate indicator within the repeating cycle of the waveform and determining in which cycle the nine-coordinate indicator is located. The induced voltage is detected from the installation position of the rough position sense line that gives the maximum value.

This is called a second conventional device.

Furthermore, other conventional devices, as described in Japanese Patent Publication No. 57-10448, have sense lines ls, lc as described above.
In order to determine in which repetition period the coordinate indicator is located, two sense lines Is are similarly placed at a pitch P' that is slightly different from the pitch P of the sense lines As and lc.
, l'c, are further laid, and the sense line Is of these two trees is
.

Position information P'o obtained by lc and previous position information P
.

It is determined by the difference between

In the coordinate reading range, the pitches P,
P' is set. In other words, the relationship between rL, P, and P' is Le・p=(+z−t)・P′・
...Tap... (It's 11.

This is called the third conventional device.

The number of sense lines in the first conventional device described above is such that the loop width of the sense lines is 1. Let L be the coordinate reading range.

It is approximately L/l and is proportional to the coordinate reading range. The loop width l cannot be made unnecessarily large due to the relationship between the diameter of the excitation winding built into the coordinate indicator and the desired seven-wire conduction characteristics.
(7rL (It is set to leprosy.

Further, the total number of sensors η%ls, lc and coarse position sense lines in the second conventional device described above is smaller than that of the first conventional device, but the number of coarse position sense lines is smaller than that of the first conventional device.
The pitch P is determined by the pitch P, which is approximately L/P, which is also proportional to the coordinate reading range. The pitch P cannot be made unnecessarily large due to the relationship with the diameter of the excitation winding mentioned above, so it must be 2 to 3c! It is set to about rL.

In this way, the first. In the second conventional device, the number of sense lines is proportional to the size of the coordinate reading range, and as the coordinate reading range becomes larger, the number of sense lines increases in proportion to the size. About this.

As the coordinate reading range increases, the number of sense lines increases, and the scale of the switching circuit increases to connect each sense line terminal to the induced voltage detection circuit in a time-sharing manner, and the induced voltage detection of all sense lines increases. This results in an increase in the detection time and a decrease in the coordinate reading speed.

Further, in the case of the third conventional device described above, only four sense lines ls, lc, Is, lc are required for the detection coordinate axis.

However, when trying to expand the coordinate reading range, the pitch P,
As mentioned above, P is the diameter of the excitation winding and the induced voltage characteristics of the sense wires (the induced voltage of the sense wires ls and lc changes sinusally with respect to the position of the coordinate indicator (2)). It is not possible to make it too thick due to the relationship of
), as n increases, the relationship between P and P becomes PZ
P, and eventually the position information becomes p□:p'0,
As the difference between Po and P'o becomes smaller, there is an increased possibility that an error will occur in detecting which (repetition period) the coordinate indicator is located within.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into consideration the expansion of the coordinate reading range or the increase in size, and there are problems such as a decrease in the coordinate reading speed and coordinate detection errors.

The purpose of the present invention is to expand the coordinate reading range and increase the size of the coordinate reading range.
An object of the present invention is to provide a coordinate reading device that prevents a decrease in reading speed and errors in coordinate detection.

Another object of the present invention is to provide a coordinate reading device that can increase the coordinate reading speed within the same coordinate reading range as the conventional one.

[Means for solving problems]

In order to achieve the above object, the present invention has a micro-position consisting of an electric conductor wire that has loop-shaped portions at intervals of P and is connected so that the directions of current flowing in adjacent loop-shaped portions are opposite to each other. A fine position sense line group in which a plurality of sense lines are laid on a flat plate, shifted by a predetermined shift width Z in parallel to the detection coordinate axis.

A group of rough position sense lines laid on the flat plate to divide the coordinate reading range into areas with a width twice or less than the pitch P.

An induced voltage detection circuit that detects the magnitude of an alternating induced voltage induced in each sense line of the fine position sense line group and the coarse position sense line group.

A polarity determination circuit that detects whether the phase of the alternating induced voltage of the fine position sense line is in phase or opposite to the phase of the excitation alternating voltage supplied to the excitation winding built in the coordinate indicator.

It has a maximum value fine position sense line detection circuit for detecting the fine position sense line from which the maximum induced voltage can be learned among the fine position sense line group, and the induced voltage detection circuit and the polarity determination circuit for the fine position sense line group. A fine position detection circuit that detects a position within a period having a period twice the pitch P of the coordinate indicator based on the output result of the circuit and the maximum value fine position sense line detection circuit.

Based on the output results of the induced voltage detection circuit and the fine position detection circuit for the coarse position sense line group.

A coarse position detection circuit is provided which detects in which period the coordinate indicator is located and calculates the position of the reference point of the detected period, and the inner period position obtained by the fine position detection circuit and the coarse position detection circuit is provided. The position of the coordinate indicator is determined by the sum of i and the periodic reference point position.

[Effect]

The fine position sense wires are connected so that the directions of currents flowing in adjacent loop-shaped parts are opposite to each other, so the magnitude of the alternating induced voltage of the fine position sense wires is the same as that of the coordinate indicator. The position reaches its maximum at the center position within the loop of the loop-shaped portion, decreases as it moves away from the center position, increases again as it approaches the adjacent loop-shaped portion, and reaches its maximum at the center position within the loop.

At this time, the phase relationship between the alternating induced voltage and the excitation alternating voltage supplied to the excitation winding is reversed from in-phase to anti-phase or from anti-phase to in-phase. (Either in phase or out of phase.

) In other words, the dielectric voltage characteristic of the fine position sense line is repeated with a period of 2P for the arrangement pitch PK of the loop-shaped portion. Here, if the reference point of the detection coordinate axis is determined and the coordinate reading range is divided by the period of 2P.

The fine position detection circuit detects which coordinate indicator is within the loop shape portion of the fine position sense line by the maximum value fine position sense line detection circuit that constitutes the circuit, and also detects the result of the polarity determination circuit. Then, it is detected which of the loop-shaped portions of the fine position sense line corresponds to which phase of the alternating induced voltage corresponds to the phase of the excitation alternating voltage, whether in phase or in phase with the phase of the excitation alternating voltage.

In other words, if the fine position sense line group is composed of 1 fine position sense lines shifted by Pln, it is possible to detect in which of the small areas obtained by equally dividing one period 2P into 2 the coordinate indicator is located. Furthermore, the detailed position within the small region can be determined by calculating the maximum induced voltage value and the induced voltage values of a fine position sense line that has a loop-shaped portion near the fine position sense line that provides this, or of all fine position sense lines. Detect from relative relationships.

In this way, the fine position detection circuit detects a position within a period where one period is 2P.

The coarse position detection circuit detects a coarse area divided by the coarse position sense line by detecting the coarse position sense line that gives the maximum value among the induced voltages of the coarse position sense line group.

At this time, since @Q of the coarse region is set to Q<2P with respect to 2P, which is the period of the induction characteristic of the fine position sense line, the detected coarse region is one of the periodic regions in which the reading range is divided by the period 2P. It may correspond to a part of only one periodic region, or it may span two adjacent periodic regions. At this time, these two periodic areas are defined as the 9th periodic area and the +1st periodic area from the one closest to the reference point of the detection coordinate axis, and the coarse detection area is the periodic self-position Rs of the 1st periodic area.
from.

Assuming that it corresponds to the inner period position ftRe of the +1th period region.

Rough area width Q'' (2P - Rs) +Re<2P
・－－－(Since it is 21, Re < Rs ・・・・・・・・・・・・・・・
...(3), and the periodic self-position value obtained from the fine position detection circuit is TH= (Re + Rs) /
2 = - River (Which periodic region it belongs to can be determined depending on whether it is larger than 41 or not. By the way, the value of the periodic self-position obtained from the fine position detection circuit is the periodic number set corresponding to each coarse position sense line. Depending on whether it is larger than the judgment threshold TH.

Detects a unique period and outputs the position of the reference point for that period.

In this way, the value of the circumferential position of the fine position detection circuit,
The position of the coordinate indicator is determined by adding the period detected by the coarse position detection circuit to the value of the position of the reference point.

In this way, in the present invention, the repetition period width of the induced voltage characteristic of the fine position sense line can be made twice the arrangement pitch P of the loop-shaped portion, so the number of coarse position sense lines can be halved. . Also.

The arrangement pitch P of the loop-shaped portion of the fine position sense line can be increased in proportion to the number of fine position sense lines of the fine position sense line group, and conversely, the period 2P of the number of coarse position sense lines becomes large.
It decreases in proportion to the number of fine position sense lines. Therefore, since it is possible to reduce the total number of sense lines, it is possible to increase the scale of the switching circuit for connecting each sense line terminal to the induced voltage detection circuit in a time-sharing manner in order to expand the coordinate reading range and increase the size.
It is possible to prevent an increase in the detection time for detecting the induced voltages of all sense lines and a decrease in the coordinate reading speed.

Furthermore, as shown in equations (2) and (3), the difference between Re and Rs increases as the coarse region width Q becomes smaller with respect to the period 2P, and the difference between the judgment threshold TH in equation (4) and Re,
As the difference between Re increases, near the boundary of the coarse area (area where the induced voltages of adjacent coarse position sense lines are almost equal), due to placement errors of the coarse position sense lines, induced voltage detection errors, etc., adjacent areas may be mistakenly connected. Even if we detect the coarse position sense line as the sense line that gives the maximum induced voltage.

If the width of such erroneous detection is less than or equal to (Rs-Re)/2, the correct cycle can be detected.

Therefore, erroneous detection of the position of the coordinate indicator can be prevented even when the coordinate reading range is expanded and the size of the coordinate indicator increases.

〔Example〕

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

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

5.6.7 and 8 are flat plates made of insulating material and are laminated together. The flat plate 5 has a fine position sense line group 51 around the X axis shown in FIG. 3, and the flat plate 6 has a group of fine position sense lines 51 around the
A group of rough position sense lines 61 around the shaft are laid. flat plate 7
, a Y-axis circumferential fine position sense line group 71 is obtained by rotating the same laying pattern as the X-axis fine position sense line group 51 by 900 rotations.
However, on the flat plate 8, a Y-axis circumferential rough position sense line group 81 is laid, which is obtained by rotating the same laying pattern as the X-axis circumferential coarse position sense line group 61 by 90 degrees.

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

The induced voltage detection circuit 10 includes an amplifier 11. Filter 12° Sample and hold circuit 13. A/D converter 14. It is composed of an absolute value conversion circuit 15 and a peak timing detection circuit 16.

The output of the alternating voltage generation circuit 2 and the output 232 of the control circuit 23 are connected to the peak timing detection circuit 16.
The output of this peak timing detection circuit 16 is connected to the S-H control terminal of the sample hold circuit 13.

17 is a polarity determination circuit, the output of the A/D converter 14 is connected to its input terminal, and the output 171 is the control terminal of the absolute value conversion circuit 15 and the input terminal of the fine position detection circuit 19 that constitutes the coordinate detection circuit 18. It is connected to the.

The output of the absolute value conversion circuit 15, that is, the output lot of the induced voltage detection circuit 10, is connected to the input terminals of the fine position detection circuit 19 and the coarse position detection circuit 20 forming the coordinate detection circuit 18.

The coordinate detection circuit 18 includes a fine position detection circuit 19. The output of the fine position detection circuit 19 is connected to one input terminal of the adder 21 and the other input terminal of the coarse position detection circuit 20.

The output of the coarse position detection circuit 20 is connected to the other input terminal of the adder 21. The output of the adder 21 becomes the output 181 of the coordinate detection circuit 18.

23 is a control circuit, and the switching circuit control signal 231 is sent to the switching circuit 9. Fine position detection circuit 19. and the coarse position detection circuit 20, the A/D converter control signal 233 is connected to the A/D converter, and the coordinate detection circuit control signal 234 is connected to the coordinate detection circuit 1.
8 is connected.

Further, the fine position detection circuit 19 includes, as shown in FIG. 2, a sense line data storage circuit 191 consisting of an absolute value memory 19]1, a polarity memory 1912, and a sense line number memory 1913, a two-signal conversion circuit 19l, and a normalization circuit. 193° position conversion circuit 194. Maximum fine position sense line detection circuit 19
59 period offset value calculation circuit 196 and adder 1
It consists of 97.

The coarse position detection circuit 20 includes a maximum value coarse position sense line detection circuit 2011, a cycle number determination circuit 202, and a cycle reference point position calculation circuit 203.

Operation overview of this embodiment It is the excitation alternating voltage of the excitation winding drive circuit 1.

When the excitation winding built into the coordinate indicator 4 is excited, an alternating magnetic field is generated around the excitation winding. This coordinate indicator 4
When approaching the flat plates 5 to 8, the alternating magnetic field causes the flat plate 5 to
An alternating induced voltage is induced in each sense line of the sense line groups 51 , 61 , 71 and 81 laid down in the sense lines 51 , 61 , 71 and 81 .

The switching circuit 9 receives the switching circuit control signal 231 of the control circuit 23.
and each sense line group 51 , 61 , 71
and a switch (not shown) connected to each sense line to select one of the 81 sense lines.
Only the corresponding switch is closed.

The alternating induced voltage of the selected sense line is guided to the induced voltage detection circuit 10.

The switch 11@times%23 controls the switching circuit 9 in a time-division manner to select each sense line.

The induced voltage detection circuit 10 detects the magnitude of the alternating induced voltage of the sense line selected by the switching circuit 9 (referred to as an induced voltage value) and supplies it to the coordinate detection circuit tSt.

Further, the polarity determination circuit 17 determines whether the phase of the alternating induced voltage of the sense line selected by the switching circuit 9 is in phase with the phase of the excitation alternating voltage, and supplies the result to the coordinate detection circuit 18 .

The coordinate detection circuit 18 detects the induced voltage value of each sense line.

Based on the determination result of the polarity determination circuit 17, the position of the coordinate indicator 4 is determined.

To be more specific, the fine position detection circuit 19 that constitutes the coordinate detection circuit 18 detects a fine position based on the induced voltage value of each sense line of the fine position sense line group 51 and the determination result of the polarity determination circuit 170. The coarse position detection circuit 20 detects the coarse position based on the derived value of each sense line of the coarse position sense line group 61 and the output value of the fine position detection circuit X9.
By adding both values by the adder 21, the position of the coordinate indicator 4 in the X-axis direction is determined. Similarly, microtopic sense whip axis 71. The position indicator 4 is determined by the position sense line group 81.
Determine the position in the Y-axis direction.

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, the following explanation will only describe the method of determining the position in the X-axis direction and the operation.

Next, details of each component will be explained.

Laying pattern of fine position sense line group FIG. 3 shows a laying pattern of fine position sense line group 51 according to an embodiment of the present invention.

The fine position sense wire group 51 includes fine position sense wires 81 which are electrical conductor wires that have loop-shaped portions spaced apart by a pitch P and are connected so that the directions of current flowing in adjacent loop-shaped portions are opposite to each other. It is composed of four wires: S2, S3, and S4. These four fine position sense lines are placed on the flat plate 5 by a predetermined shift width Z, here Z =
Assuming that P/4 = l, the cables are laid by shifting them by Z parallel to the X axis.

One end of each fine position sense line 81 to S4 is connected to a terminal TSL to T
The signal is guided to the switching circuit 9 via S4.

In addition, the other ends of each fine position sense line S] to S4 are connected to each other at point H shown in Figure 1, and adjacent loop connections connect adjacent loop-shaped portions of each fine position sense line from that connection point. It is led to a terminal TSc disposed near the terminal TSI-TS4 via a return line Sc made of an electric conductor wire laid parallel to the section.

The induced voltage of each fine position sense line S1 to S4 is the terminal TSc
The induced voltage detection circuit 10 detects the induced voltage via the switching circuit 9 based on the alternating induced voltage generated between the terminals TS+ and TS4.

Induction characteristics of fine position sense line FIG. 5 is a diagram for explaining the induction characteristics of one fine position sense line 81.

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

Figure 5 (2) shows the fine position sense 'mSl' shown in (1).
The installation pattern is shown below. Position areas B, D, and F shown in the figure are loop-shaped portions, and position areas A, C, E, and G are connecting portions between adjacent loops. Point H is fine position sense line S1
This is the connection point of the return line SC. Also.

The arrows in Fig. 5 (2) and (3) indicate the direction of the current in the electrical conductor wire portion of each part when the current flows from the terminal TSI through the connection point H to the terminal TSc of the return line Sc. It is something.

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 parts are connected by the adjacent inter-loop coupling line as shown in FIG. 5(1) or (2), the directions of currents flowing in the adjacent loop-shaped parts 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 coupling portion between adjacent loops and the return line Sc are opposite to each other. Therefore.

When the coordinate indicator 4 is positioned at the 81st point in FIG. 5(2).

Let e (Sxg ) be the electromotive force induced in the connection between adjacent loops in the position area of E or the induced current associated with this, and the electromotive force induced in the return line Sc in the position area of E or the induced current associated with this. If we let e(Scg) be e(Scg), both electric conductor wires have the same length and are placed close to each other in parallel, so e(3zx) = e(Scg)...
・・・・・・・・・・・・・・・(5)

Looking at this between the terminals TSI and TSc, the current flows from TSI to TS2 are in opposite directions, as shown by the arrows in FIG. 5(2).

The electromotive force generated in both or the induced current caused by this will be canceled by each other. Therefore, A, C, and E
, the inter-adjacent loop coupling portion of the position region of G and its vicinity,
The portion of the return line Sc arranged in parallel does not contribute to the induction characteristics (only the solid line portion shown in FIG. 5 (3) is the alternating magnetic field created by the excitation winding built into the coordinate indicator 4 As a result, the fine position sense line Sl shown in FIG. 5(2)
The electric conductor wire shown in the solid line part only contributes to the generation of an alternating induced voltage, and the solid line part forms a clockwise loop of an l turn in the position area B, and the solid line part forms a clockwise loop in the position area D. In this case, a one-turn counterclockwise loop is formed, and in the F position region, an l-turn clockwise loop is formed.

This means that the one-turn loop line shown in Figure 5 (4) is
Loop lines SR, SD, SF are arranged in the position areas of , D, F, and the alternating induced voltages eB, eD,
It is equivalent to adding eF. (The voltage of eo is -
(Please note that the standard is different from efl+eF) Figure 5 (5) shows this situation, where the horizontal axis shows the position of the coordinate indicator 4, and the vertical axis shows the magnitude of the alternating induced voltage.
The phase relationship with the excitation alternating voltage applied to the excitation winding is shown.

eQ + eQ, ep in Fig. 5 (5) is the loop line S
The magnitudes of the alternating induced voltages of R, SD, and SF are shown, and the thick solid line is the sum of these. loop line SB,
eQ + eF reaches its maximum value at the center of the loop of Sp, and decreases as it moves away from the center (eQ reaches its maximum value at the center of the loop of loop line SD, but the phase of the alternating induced voltage The phase is opposite to the phase at the center of the loops of SB and SF.The induction characteristics of each loop line are the same, only the placement positions of the loops are different, so the result of adding these is shown as a thick solid line. As shown, the induced voltage reaches a maximum in the center of the position area of B in the same phase, and at point Co (the center point between the loop-shaped parts), the induced voltage becomes zero, the phase is reversed, and it reaches the maximum in the opposite phase at the center of the position area of D, At point Eo, the induced voltage becomes zero again, the phase is reversed again, and it becomes maximum in the same phase at the center of the position area of F.

In this way, the induced voltage characteristic of the fine position sense line S1 is a repeating characteristic with a period of 2P, which is twice the arrangement pitch P of the loop-shaped portion.

Induction characteristics of the fine position sense line group Each of the fine position sense lines 81 to S4 is shown in FIGS. 3 and 5 (
As shown in 1), the shift width Z = P/ in the X-axis direction
Since the sense lines are laid staggered by 4=l (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 (jl (magnitude of alternating induced voltage) of each fine position sense line St, and does not include one phase information. Also, FIG. 6 (4) shows Each fine position sense line 5l-8 at each position
This shows the maximum value of the induced voltage V (t, l) of 4, and the fine position sense line giving that value is in order from the old point as shown in the figure KS1.32, Sa, 84, S
t.

It becomes like SL,... In addition, the phase of the alternating induced voltage of the fine position sense line that gives the maximum value is different from the phase of the excitation alternating voltage that drives the excitation winding, as shown in Figure 6 (5). The width is in reverse phase) and is repeated. In this way, the induction characteristics of the fine position sense line group are repeated with a period of 2P.

Switching circuit operation timing FIG. 7 shows the operation timing of the switching circuit 9. (1) indicates the code of the sense line Si to be selected supplied from the control circuit 23. The switching circuit control is number 231.
, +2) is the opening/closing timing of the internal switch SWL of the switching circuit 9 connected to the sense line SL, and (3) is the output signal of the switching circuit 9 which is connected to the selected sense line SL.
shows the alternating induced voltage v(sL) of .

In this way, the switching circuit 9 is controlled by the switching circuit control signal 231 to select each sense line in time series, and guides the alternating induced voltage of the selected sense line to the induced voltage detection circuit IO.

Induced voltage detection circuit The induced voltage detection circuit 10 first amplifies v(i) with an amplifier 11 in order to detect the magnitude of the alternating induced voltage signal V[j) of the sense line i selected by the switching circuit 9. After unnecessary noise components are removed by the filter 12, the signal is input to the sample-and-hold circuit 13.

The sample and hold circuit 13 is controlled by the output signal of the peak timing detection circuit 16, and holds the peak value of the amplitude of the alternating induced voltage signal VfLl.

FIG. 8 shows the internal configuration of the peak timing detection circuit 16. The peak timing detection circuit 16 includes a low pass filter 161. Comparator 162 and D-type flip-flop 1
It consists of 63. The corner frequency fc of the low-pass filter 161 is the alternating frequency f of the alternating voltage generating circuit 2,
Since it is set sufficiently small, low-pass filter 1
61, a signal whose 0 phase is shifted by 9σ with respect to the excitation alternating voltage signal (FIG. 9 (1)) of the alternating voltage generating circuit is obtained. The comparator 162 (shown in FIG. 9(2)) is
By comparing this 90° shifted signal with a predetermined value of zero, a rectangular wave that rises at the timing of the positive peak value of the excitation alternating voltage signal is output as shown in FIG. 9 (3),
This is the Dfi7177 block flop 163 (::Ioc
Supplied to the k terminal.

At the Data input terminal of the D-type flip-flop 163.

When the sample-and-hold control signal 232 (Fig. 9 +41') supplied from the control circuit 23 at a predetermined timing is input, the sample-and-hold control signal 232 is applied to the output terminal Q of the D-type flip-flop 163 to excite the The sampled value is output at the rising timing of the rectangular wave (C1ock terminal input signal) rising at the timing of the positive peak value of the alternating voltage signal. That is, as shown in FIG. 9(5), the sample/hold circuit 13 is controlled to hold at the timing of the positive peak value of the excitation alternating voltage signal.

Here, as shown in FIG. 9(6), the switching circuit control signal 231 is set to T to select the sense lines Sn and 3rL+14.
2 timing, and in contrast, Fig. 9 (7)
The alternating induced voltage signals V (Sa), V (SFL+1
) is input, V(SrL) is in phase with the excitation alternating voltage signal, and V(SrL+1) is.

Assuming that the excitation alternating voltage signal and the alternating induced voltage signal have the opposite phase,
The sample and hold circuit 13 has Itc, T as described above.
The value of V(SFL) is held at timing 1, that is, at the positive peak value timing of the excitation alternating voltage signal. V(
SFL) is in phase with the excitation alternating voltage signal, so V
The positive peak value of (SFL) will be held.

Also, V(SrL+1) is held at the timing of T4, but since V(SrL+1) is in the opposite phase to the excitation alternating voltage signal, the negative peak value of V(SrL+1) is held. That will happen. This situation is shown in Figure 9 (
8).

These values held by the sample and hold circuit 13 are converted into digital values by the A/D converter 14 as shown in FIG. 9 (9). At this time, V (S
rL), V (SrL+x), the output of the A/D converter 14 is V (Sn), V (SrL+1), V(SrL) is a positive value, V(S+z+t
) will take a negative value, and its size is v(Sa)
, V (SFL+1).

Therefore, as shown in FIG. 8, the polarity determination circuit 17 is composed of a comparator 170, and determines whether the output of the A/D converter 14 is larger than a threshold value (in this case, zero) In other words, the alternating induced voltage V(SrL
) is in phase with the excitation alternating voltage signal. This comparator 170 is a comparator that compares digital values, but it is composed of a comparator that compares analog values with the output of the sample-and-hold circuit 13 as one comparator input and the other comparator input as zero. However, the same effect can be obtained by outputting the comparison result at the hold timing of the sample-and-hold circuit 13.

The output (171) of the polarity determination circuit 17 is supplied to the coordinate detection circuit 18 and controls the absolute value conversion circuit 15 forming the induced voltage detection circuit 10.

Based on the output result of the polarity determining circuit 17, the absolute value converting circuit 15 determines that when the output of the A/D converter 14 is A,
and -A, A (both A are positive values) is output.

That is, the induced voltage detection circuit 10 detects the amplitude v of the alternating induced voltage V (SrL) of the sense line Sn in this way.
(Sa) is output and sequentially supplied to the coordinate detection circuit 18.

The coordinate detection circuit 18 receives a switching circuit control signal 231 (a code corresponding to the sense line to be selected, hereinafter referred to as a sense line number) from the control circuit 23.

The magnitude V (SrL) of the alternating induced voltage V (Sa) of the sense line Sn selected by this and detected by the induced voltage detection circuit 10 and whether V (SfL) is in phase with the excitation alternating voltage by the polarity determination circuit 17. Based on the detected polarity determination result, the position of the coordinate indicator 4 is determined.

The coordinate detection circuit 18, as described above and shown in FIG.
) ~ V (S4) and the polarity determination result, detect the position within a period of 2P, which is twice the arrangement pitch P of the loop-shaped portion, which is the induced voltage characteristic of the fine position sense line group 51. Fine position detection circuit 19 and coarse position sense line group 61 (fourth
Based on the induced voltage shown in the figure (details will be described later) and the output result of the fine position detection circuit 19, it is determined in which periodic region divided by the width of 2P the coordinate indicator 4 is located. It is comprised of a coarse position detection circuit 2o that detects and outputs the position of the reference point in the periodic region, and an adder 21 that adds the output values of both.

Below, fine position detection circuit 19. The operations of the coarse position sense line group 61 and the coarse position detection circuit 20 will be explained.

Fine position detection circuit The fine position detection circuit 19 detects the fine position sense lines 81 to S4 based on the switching circuit control signal 231 ((sensing line number), and detects the sense line numbers l to 4 and the corresponding induced voltage. v(1
) to v(4) and the determination result P(1) of the polarity determination circuit 17
) to P(4) are stored in the negative sense line data storage circuit 191. Specifically, the polarity determination result P (11 to P
(4) is stored in the polarity memo I71912 and the sense line numbers 1 to 4 are stored in the sense line number memo U1913. induced voltage V
(t-) and the polarity determination result P(1) are stored in correspondence with the sense line numberer.

Here, as shown in Figure 6 (6), the coordinate reading range is set to 2.
The reference point of the t-th periodic area AS4, which is divided by a width of P and counted from the reference point of the coordinate axes, is the Ri point, and the RL point is the reference point.

As shown in FIG. 6(5), it is assumed that the polarity of the alternating induced voltage of the sense line giving the maximum induced voltage is reversed from the opposite phase to the same phase. Also, a periodic area A of 2P width with the RL point as the reference point.
SE is abbreviated as 0 cycle number.

Although the fine position detection circuit 19 cannot detect in which periodic region the position of the coordinate indicator 4 is located based on the stored value of the sense line data storage circuit 191, it can be set as described above. The position of the cycle from the reference point is detected as follows. ``First, the maximum value fine position sense line detection circuit 195K.

The maximum value of the induced voltages v(1) to v(4) is detected and the number of the fine position sense line giving the maximum value is output.

is a value of 1 to 4.

If the coordinate indicator 4 is positioned at the point A shown in FIG. 6(1), the induced voltage v of the fine position sense line S] to S4 is as shown in FIG. 6(4). (1)～■(4)
The maximum value is the induced voltage v(3) of the fine position sense line S3.
becomes. Therefore, the maximum value fine position sense line detection circuit 195
The maximum value fine position sense line number which is the output of is 3,
It can be seen that the coordinate indicator 4 is located within a small area A3 or A7 of the small areas (A1-As) obtained by dividing the period shown in FIG. 6 into eight.

Further, the fine position sense line S3 giving the maximum induced voltage
Which small region is included can be determined from the polarity of the alternating induced voltage with respect to the excitation alternating voltage, that is, the polarity determination result P +3+ K stored in the polarity memory.

Here, since the phase is positive, it can be seen that the coordinate indicator 4 is located within the small area A3.

In this way, Ic, maximum value fine position sense line detection circuit]95
outputs the polarity determination result P(rL) of the maximum fine position sense line number and its alternating induced voltage, and supplies this to the intra-period offset value crossing circuit 196.

As described above, the intra-period offset value calculation circuit 196 calculates in which small area the coordinate indicator 4 is located based on the maximum fine position sense line number and its alternating induced voltage polarity determination result P(rtl). Detect where you are located.

Calculate the offset value of the period of the detection small region from the reference point.

The width of the small area is the shift width of the fine position sense line 2, so the offset value XOF? teeth.

However, the maximum fine position sense line number is 1 to 4P (
rLl is calculated based on the result of polarity determination with respect to the excitation alternating voltage of the alternating induced voltage of the fine position sense deprivation that provides the pulse.

The detailed position within the detected small area is determined by the two-signal conversion circuit 19l.
, the normalization circuit 193 and the position conversion circuit 194 detect as follows.

First, in the two-signal converting circuit 192, the induced voltage V(
1) ~ V (4, 1i) Two composite voltages vs and Vc shown in the following formula are calculated.

Vs=V(n)+V(rL+t)-V(n-+-z)
−V(rc-t) −・−−−−−・(7) VC=
V(rLl-V(n+1)-V(rL+2)+V(rL
-1) ・-・”・18 However, n is the maximum fine position sense line number and the value V from 1 to 4 (il is the induced voltage of the fine position sense line SL, that is,
When nw3, V(+zl, V(n+1),
V(rL+2) and V(rL-t) are the fine position sense lines 33, B4, 81 and 52 (7) induced voltage V
(31, Vt4), corresponds to V(t)*YohiV(2)K.

In other words, ■(ru+1) is the maximum fine position sense line S
The induced voltage, V(ni), of the micro-position sense line having a loop-shaped part on the right side of the n loop-shaped part is V(n-i).

The induced voltage and V (+z+2) of the fine position sense line which has a loop shaped part on the left side are determined by the maximum value of the four fine position sense lines, which is farthest from the loop shaped part of the fine position sense line. corresponds to the induced voltage in the fine position sense line with .

This situation is shown in FIG. 1O (1). At this time, each fine position sense line is arranged so as to be shifted by a shift width Z=l (loop width of the loop-shaped portion).

The induced voltage characteristics of each fine position sense line Si are shown in Figure 10 (2
)become that way. This figure shows the maximum fine position sense line Sn
This figure shows the induced voltage characteristics of a micro-position sense line having a loop-shaped part in the center and a loop-shaped part around it, and is a partially enlarged view of FIG. 6(3).

B is the left end of the loop-shaped part of the fine position sense line S.

If the right end is point B2 and the center is point B1, then Bo
At the point, the induced voltage ■(n) is equal to V(Rule l) vb.

The value, V(rL-H), is equal to V(n-1) and becomes the VdO value.

Also, at point B2, the induced voltage V(+zl, V
(n+1) is.

Vb value, V (rL-t) tV (rL+2)
HaVd(7) value tonal. Also, at the point B1, the induced voltage V (nl is the value of the maximum value Va, V (n-1)
, V (rL+1) is the value of Vc, V(rL+2
))! Zero door! 6゜Kokote, voltage value Va, Vb
, Vc, Vd (7) The magnitude relationship is.

Va>Vb>Vc>Vd...
・・・・・・・・・・・・・・・(9).

Since each fine position sense line exhibits an induced voltage characteristic with respect to movement within the loop-shaped portion of the fine position sense line Sn of the coordinate indicator 4, the composite voltage Vs of the two-signal circuit 192
, Vc are as shown in FIG. 1O (3).

The composite voltage Vs becomes zero at 80 points and gradually increases.

At point B1 it becomes Va, which increases further and at point B2 it becomes 2 (Vb
-Vd). Further, the composite voltage Vc becomes 2 (Vb - Vd') at point 13o, becomes gradually smaller in contrast to Vs, becomes Va at point Bt, becomes further smaller, and becomes zero at point B2.

The normalization circuit 193 calculates the relative magnitude ρ of the composite voltages Vs and Vc of the two-signal conversion circuit 192. this is,
Fluctuations in the excitation alternating voltage that drives the excitation winding.

Due to variations and variations in the amplifier 11 constituting the induced voltage detection circuit 10, the induced voltage values of each sense line, that is, the values of Va, Vb, Vc, and Vd described above, vary, and as a result, the composite voltages Vs, V
Variation in cO value If one or both of Vs and Vc itself is used, the correct position within the loop-shaped portion cannot be detected. Therefore, in order to remove the influence of these fluctuations and variations and obtain one coefficient value corresponding to the position within the loop, a normalized value ρ indicating the relative magnitude of Vs and Vc is calculated. be.

The normalization circuit 193 calculates the relative magnitude of the zero composite voltages Vs and Vc, that is, the normalized value ρ, using the following equation.

Vs This normalized value ρ is, as shown in FIG. 10 (4), Vs
Since s and Vc become a symmetrical composite voltage around point B1,
At point 80, it becomes O, and as the coordinate indicator 4 moves toward point B2, it gradually increases, and at point Bt, l/ becomes 2,
At point B2, it becomes 1. The characteristics of this normalized value ρ are
If the induced voltage characteristics of each fine position sensing line shown in FIG.

In other words, the six normalized values ρ from 0 to 1 correspond to only one position within the loop shape group.

Therefore, by knowing the normalized value ρ, it is possible to detect the position Δ, r within the loop shape section.

The position conversion circuit 194 calculates the position ΔX within the loop-shaped portion based on the normalized value ρ. ΔX.

As shown in FIG. 10 (4), the position of the coordinate indicator 4 is 8.
0 point is O, B1 point is Z/l, B2 point is Z(
Z is the slenderness iZ of each fine position sense line Si, and here it is K, which is the same as the loop width l of the loop-shaped part), then ρ is 0≦ρ for Δ2 where 0≦ΔX≦2 It is a unique function of ΔX which takes a small value of ≦1, and is expressed as follows.

ρ=da (Δ−) ・・・・・・・・・・・・
...(0) This function! (ΔX) is ρ=1・ΔX ・・・・・・・・・・・・・・・
If the function is (12), then Δ3: is Δx = 7.・ρ・・・・・・・・・・・・
It is obtained by (13). However, as shown in Figure 10 (4), the function! ! (Δ2) is for ΔX,
Takes the value of a non-linear relationship.

So, let's use this function in advance! Inverse function 7 of l(Δ2) (
ρ) Δx=g(ρ) ・・・・・・・・・・・・・・・
If a function table satisfying (14) is obtained experimentally, ΔX can be obtained from the value of the function table corresponding to the value of ρ.

Therefore, the 6-position conversion circuit 194 is specifically configured with a nonvolatile memory (for example, a read-only memory), and stores the above-mentioned inverse function 7 (ρ) at the address corresponding to the normalized value ρ. do.

As shown in Figure 10 (5), this inverse function value is KO≦ρ
It takes a value of 0≦ΔX≦Z for a value of ρ≦1. Since it is not possible to memorize the value of 7 (ρ) for all ρ, at the very least, divide Z into equal parts (vertical axis) so that the desired positional resolution can be obtained from the curve shown in Figure 10 (5).
The value of ΔX for ρ at each point is stored.

By configuring the trap 1 position conversion circuit 194 in this way, the normalized value ρ obtained by the normalization circuit 193 is
To the output of the position conversion circuit 194 as an input.

The position ΔX within the loop shape section can be obtained.

The position ΔX within the loop shape section obtained in this way,
The above-mentioned intra-period offset value xop'y is added by an adder 197 to obtain a period self-position X, which is the position from the reference point in one period area, and this is outputted as an output value of the fine position detection circuit 19.

As shown in FIG. 11, position X within one cycle! is 2P (=
8Z) is repeated, so position X within 6 cycles
The absolute position of the coordinate indicator 4 cannot be determined only by manual operation.

To determine this, press the coordinate indicator 4.

The position of the reference point Ri of the periodic area ASL (also the period number) is detected.
coordinate values).

The role of the coarse position sense line group 61 and the coarse position detection circuit 20 is to detect the period number t of the periodic area ASL in which the coordinate indicator 4 is located and to detect the position of the period reference point RL. .

The configuration and operation of these will be explained below.

Coarse position sense line group The coarse position sense line group 61 is a sense line for dividing the coordinate reading range into coarse regions having a width Q of less than the period width 2P of the induced voltage characteristic formed by the fine position sense line group 51 described above. .

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

As shown in the figure, it is composed of a plurality of coarse position sense lines laid on a flat plate 6 by shifting the coarse position sense GL consisting of a loop-shaped electric conductor wire and shifting it by a width ZG=Q<2P in parallel to the detection coordinate axis. are doing. Here, if the loop width of the loop shape of the rough position sense line is IG, Fig. 4 Te4t,
Zc = 6Z < 2P = 8Z, lG near 4.

One end of each rough position sense line GL is connected to each H! A return line GcK made of an electric conductor wire is connected at a point, and one end of a return line iGc is led to a terminal TGc. In addition, each coarse position sense 1 (
The other end of iGj is led to a terminal TGLK arranged near the terminal TGc by an electric conductor wire laid in parallel and close to the return line Gc, as shown in FIG.

Each terminal TGt is sent lff1 to the induced voltage detection circuit 10 via the switching circuit 9, and returned to the terminal TGi of the coarse position sense line Gi in the induced voltage detection circuit IO.
Based on the alternating induction voltage generated across Gc, the magnitude of the induced voltage (voltage) is detected.

The characteristics of the dielectric voltage generated between the terminal TGL of each coarse position sense line Gi and the terminal TGc of the return line Gc are similar to the relationship between the fine position sense line SL and the return line Sc described above.

Since the induced voltages generated in the portion of the rough position sense line that is laid close to and parallel to the return line Gc and the corresponding portion of the return line, or the induced current that accompanies this, cancel each other out, the loop width shown in FIG. It becomes equal to the loop line G'E having 1z (=62).

At this time, the induced voltage V(Gi) of each coarse position sense line Gi
The characteristics of each V (GL ), if the largest rough position sense line GL in the same phase is detected, the coarse area AGL (the 12th
It is possible to detect the coarse area AGL in which the coordinate indicator 4 is located (shown in (3) in the figure).

For example, if the coordinate indicator 4 is located within the loop of point A in FIG. 12, that is, the coarse position sense line Gi, each coarse position fl-
t=y Silo induction is expressed as pressure V(GL), V(Gi
+1).

. . , the one that gives the maximum value in the same phase is V(Gt) of the coarse position sense line GL, and the coarse area AGi where the coordinate indicator 4 is located can be detected.

Therefore, the control circuit 23 controls the switching circuit 9 with the switching circuit control signal 231 at a predetermined timing, similarly to the detection of the induced voltage v(Si) of the fine position sense line Si.

The alternating induced voltage of each rough position sense line GL is guided to the induced voltage detection circuit 10, and each obtained induced voltage V (Gi) and polarity determination result P (Gi) are sent to the coarse position detection circuit 20 that constitutes the coordinate detection circuit 18. be supplied to

Coarse position detection circuit The coarse position detection circuit 20 is as shown in FIG.

It is composed of a maximum value coarse position sense line detection circuit 2011, a cycle number determination circuit 202, and a cycle reference point position calculation circuit 203.

The maximum value coarse position sense line detection circuit 201 calculates P( Detect and pair the rough position sense line GrIL where Gi) is in phase (indicating that the phase of the excitation alternating voltage and the phase of the alternating induced voltage of the coarse position sense line are in phase) and where V (Gj) is maximum. Output the corresponding number m.

Whether the polarity determination result P (GL) is in the same phase or in opposite phase has an important meaning in rough position detection, and a negative phase indicates that the coordinate indicator 4 is not located within the loop of the coarse position sense line Gi. show. Therefore, as shown in FIG. 12, there is only one coarse position sense line in which P(Gi) is in positive phase, or there are two coarse position sense lines adjacent near the boundary of the coarse region. Therefore, in the former case, the number m of the only coarse position sense line IwSrn is output, and in the latter case, the number m of the coarse position sense line 3m with the larger induced voltage is output.

The cycle number determination circuit 202 determines the rough position sense line number m obtained from the maximum value coarse position sense line detection circuit 201, that is, the coarse area AG divided by the coarse position sense line group 61.
A coarse area AGm in which the coordinate indicator 4 is located within L;
From the in-cycle position XIK obtained by the fine position detection circuit 19, the cycle number N of the cycle area ASH in which the coordinate indicator 4 is located is detected.

Cycle Number Detection Algorithm The algorithm for detecting the cycle number N of the cycle area ASN in which the coordinate indicator 4 is located will be described with reference to FIG.

FIG. 13(1) shows a periodic region of the induced voltage characteristics of the fine position sense line group 51 divided into regions with a periodic width 2P.

(2) is the characteristic of the inner period #XX obtained for each period region, and (3) is the characteristic of the coarse position sense line divided into regions by the shift width ZG of each coarse position sense line of the coarse position sense line group 61. Indicates the area.

In this example, with respect to the shift width Z of the micropositional sense acid,
Since 2P=8Z and ZG=6Z, the positional relationship between the 0 period area and the coarse area is repeated with a period of 24Z as shown in FIG. Here, the boundaries between the two areas are shifted so that they do not overlap in position.

The coarse position sense line Gm indicating the maximum induced voltage obtained from the maximum value coarse position sense line detection circuit 201, that is, the coarse area AC3ttt where the coordinate indicator 4 is located, corresponds to a part of the only periodic area. Or, it will span two adjacent periodic regions.

The following margin table 1 is based on FIG.
1 shows the relationship between periodic regions ASL-1-ASL+2 and the inner-period position ftXr in each periodic region. Here, xs, xb, xc and line indicate the value of the periodic self-position XI at the boundary point of the coarse region,
1=7,5Z, xb=5.5Z, zc=3
, 5Z and -Td = 1.5Z.

In this way, even if the coarse region spans two periodic regions,
Since the range of possible values of the periodic position XI in each periodic region is different, a unique periodic region can be determined depending on which value the periodic position XI takes within six laps.

In other words, as shown on the right side of Table 1, each coarse area entry Gj~-A
, G, i+3, set in advance @-TTh to TH4. Depending on whether the position XI within 124 cycles is closer than the initial value corresponding to the detected coarse area, the cycle corresponding to the detected coarse area is set in advance. Detects one of the 1 areas.

In addition, the threshold value TH1~T) (3 is THI ” (2a+m)/2 ・= −(15)
, TH2= (xb+xa)/2- (16)'l
'13==(,rc+,rd)/2 ・・＋・＋・(1
7) Threshold value TH4 is TH<=(xa+x−8Z)/
2-- (18) may be used.

As shown in FIG. 12, the coarse area can be detected by the number of the coarse position sense line that gives the maximum induced pressure of 1. but,
At the boundary of the coarse region, the induced voltages of the corresponding coarse position sense lines become equal, and due to variations in the arrangement of the coarse position sense lines, variations in the induction characteristics, etc., the conductive voltage of any coarse position sense line C becomes large near the boundary. It is not clear whether

Therefore.

The maximum value coarse position sense line detection circuit 201 may detect the coarse area AGm corresponding to the incorrect coarse replacement sense line number mK.

However, by comparing the above-mentioned peak THi corresponding to the detected coarse area and the inner period ftXr.

Even for this erroneous detection, it is possible to horizontally compare the correct periodic region number. The range in which erroneous detection can be prevented is within the coarse region, where #XI is impossible (for example, coarse region A).
In GJ, it is xb - xa ), which is the shaded area in C (4) in FIG. In other words, even if the position area of a is detected as the coarse area AG, or the position jυ area of b is detected as the coarse area Ac1,
It is possible to detect the correct periodic region number. To what extent can false positives be prevented?

: It increases as the width Q=Zc of the coarse region becomes smaller with respect to the width 2P of the periodic region.

, Cycle number determination circuit FIG. 14 shows a specific configuration of the cycle number determination circuit 202.

2020 is a threshold memory, 2021 is a comparator, 20
22 is a cycle number memory. The threshold value memory 2020 stores the above-mentioned threshold values TH1 to TH4 for cycle number determination in correspondence with the number of the coarse position sense line, that is, the number of the coarse area. Further, the cycle number memo IJ 2022 stores the above-mentioned cycle area number in correspondence with the rough area number and the output value of the comparator 2021. When the coarse position sense line number m that gives the maximum value is input from the maximum value coarse position sense line detection circuit 201, the threshold memo 1J 2020 outputs the corresponding threshold value THL using this as an address. The comparator 2021 uses this threshold value THL and the fine position detection circuit 19
The comparison result is compared with the periodic self-position Xr supplied by The cycle number memory uses this comparison result and the rough position sense line number m as an address and outputs the corresponding cycle number N.

Period reference point position calculation circuit Period reference point position calculation circuit 203 is one period number determination circuit 2
Based on the period number N obtained from 02, the position (distance) Xc of the reference point RN of the corresponding periodic area ASN from the reference point of the coordinate axis is calculated. If the periodic region is from the reference point of the coordinate axes,
Assuming that they are arranged in the order of ASI, AS2...ASN,..., the width of one periodic area is 2P=82, so the position Xc of the reference point RN of the periodic area ASN corresponding to period number N is.

Xc = 2P・(N-1) ・・・・・・・・・
・・・・・・・・・・・・・・・(19) is obtained.

In addition, since Xc is a uniquely determined value corresponding to N, the operation of this cycle reference point position calculation circuit 203 is written in the cycle number memo 132022 of the cycle number determination circuit 2020 instead of the cycle number corresponding to N. 1 cycle number determination circuit 202 by storing Xc and acting on its behalf.
Xc can be obtained from the output of

This Xc is outputted as an output value of the coarse position detection circuit 20, and added by an adder 21 to the periodic self-position xI obtained from the fine position detection circuit 19. This addition result (Xc +
X1) is output as the output value of the coordinate detection circuit 18.

Effects of this embodiment According to this embodiment, the induced voltage characteristics of the fine position sense line are as follows:
The fine position sense line is repeated with a period of 2P for the arrangement pitch PK of the loop-shaped part, and this fine position sense line is composed of four fine position sense lines shifted by a width of Z = P/4 in the direction of the detection coordinate axis. It is possible to detect a position within a period with a period of 2P using the line group. Also, in which period the coordinate indicator 4 is located is determined by 2
Detection can be performed using a group of coarse position sense lines that divide the coordinate reading range into regions with a width Q=ZG that is less than or equal to P.

In other words, the total number of sense lines for coordinate detection can be reduced by increasing the width of the repetition period by using a smaller number of fine position sense lines and reducing the number of coarse position sense lines due to this expansion.

For example, a loop-like sense line lf with a loop width l has an approximate width Z
Compared to the first conventional device, which is composed of BrL sense lines shifted by =J, in this embodiment, the number of fine position sense lines is 4, assuming P=8Z, and the number of coarse position sense lines is 4, and the number of coarse position sense lines is 4. Shifting the position sense line! If ZQ=6Z, it becomes 8V'6 lines, and the sense line number ratio is.

Sense line number ratio” (4+ 87L/6) / 8n
・・・・・・・・・・・・(20), and r
As L increases, that is, the coordinate reading range is expanded, the sense line number ratio becomes smaller. 0.67 for 騨1 and 0.33 for roux 3. In the case of Roux 10, it is 0.22. Furthermore, compared to the second conventional device which is composed of a fine position sense line group having a width P of one period and a coarse position sense line group detecting a position of one period, the width of one period is 2 in this embodiment. The number of coarse position sensing lines can be halved since the area is enlarged by a factor of 2.

In addition, the shift width zG of the coarse position sense line is set to 2P or less,
By comparing the preset threshold value corresponding to the detected coarse area with the periodic value of the cycle width 2P, it is possible to prevent errors in detection of sitting posture due to erroneous detection of the coarse area near the boundary of the coarse area. .

Further, each end of the Q position sense line is connected to a common return line Sc.
The induced voltage of each fine position sense line connected to one end can be detected by the alternating induced voltage generated between each other end of each fine position sense line and the other end of the return line Sc, and the switching circuit 9
As for the number of terminals to be selected, the number of fine position sense lines is only four, and the circuit scale of the switching circuit 90 can be reduced. The same applies to the coarse position sense line.

In addition, for the induced voltage of each sense line, the peak value of the alternating induced voltage is held in a sample and hold circuit.

Since this is configured to be converted into a digital value by an A/D converter, the magnitude of the amplitude of the alternating induced voltage in the rectifier circuit and the rectified value are Induced voltage detection errors due to nonlinearity can be avoided. In addition, since the rectifier circuit has a zero time constant, immediately after switching the sense line, the correct rectified value cannot be obtained and A/D conversion can only be performed after a predetermined time. However, the present invention reduces this time. As a result, it is possible to reduce the induced voltage detection time per sensor and to increase the coordinate reading speed.

Another Example of Fine Position Sense Line Group FIG. 15 shows another example of the laying pattern of fine position sense lines. As shown in the diagram, the loop width of the loop shape part! If the arrangement pitch of the loop-shaped portions is P, and the directions of current flowing in adjacent loop-shaped portions are opposite to each other.

An induced voltage characteristic (FIG. 5 (5)) similar to that of the fine position sense line shown in FIG. 5 (2) can be obtained.

FIG. 16 shows the fine position sense line shown in FIG. 15.

4, which were laid with a shift width Z in the direction of the detection coordinate axis.
This is a laying pattern of a fine position sense line group 51 made up of fine position sense lines of a book.

The induced voltage characteristics of this fine position sense line group 51 are similar to those of the fine position sense line group 51 shown in FIG. 3 or FIG. 6 (1) (FIG. 6 (2) to (6)). Compared to the installation pattern shown in FIG. 3, this fine-position sense line installation pattern allows connecting portions in which the current directions are opposite to each other to be arranged closer and in parallel at the connection portion between adjacent loop-shaped portions. Therefore, the influence of these coupling portions on the induced voltage characteristics can be further reduced.

FIG. 17 shows another example of the laying pattern of the fine position sense line group 51.

The difference between this embodiment and the embodiment shown in FIG. 3 or FIG. 5 (1) K is the magnitude relationship between the loop @j of the loop-shaped portion of the fine position sense line and the shift width Z in the detection coordinate axis direction. is the difference.

In the embodiment shown in FIG. 3, Z>l (explained as Z), but in the embodiment shown in FIG. 17, Z<l. As shown in FIG. 17 (2), the induced voltage characteristics of the micro-position sense line group 51 of the bullet have a repeating characteristic with a period twice the arrangement pitch P of the loop-shaped portion, and as shown in FIG. 3. The same induced voltage characteristics as in the example can be obtained.

In addition, in both the embodiments shown in FIGS. 3 and 17, the relationship between P, Z, and the number of fine position sense sets (here, rL=<) is as follows.

Z=P/n・・・・・・・・・・・・
......(21). In this way, the relationship between the loop width l and the shift width Z can be set depending on the diameter of the excitation coil and the desired induced voltage characteristics.

Here, an embodiment in which the fine position sense line group 51 is composed of four fine position sense lines has been described.

The number of fine position sense lines is not limited to four, but may be small (although this may occur if the fine position sense line group 51 is composed of two or more fine position sense lines).

For example, fine position sensing is performed using two fine position sense lines that are arranged at a pitch P of the loop-shaped part and a loop width l of the loop-shaped part and are shifted in the direction of the detection coordinate axis @Z = P/2. If the line group 51 is configured, its induced voltage characteristics (including the phase relationship of the alternating induced voltage of each sense line to the excitation alternating voltage) are as follows.

As in the above-mentioned embodiment, it has a repeating characteristic of 2P'& period, and 1. Based on the relative largeness of the induced voltage of both micro-position sense lines and the polarity determination result,
rc can be detected.

In addition, for example, n lines (rL
>2) If the fine position sense line group 51 is configured with fine position sense lines, the induced voltage characteristic will be a repeating characteristic with a period of 2P as described above, and the maximum of the induced voltages of each position sense line will be value and the vicinity of the loop-shaped part of the fine position sense line that gives its maximum value (e.g.

Based on the relative magnitude of the induced voltage of the fine position sense line that has loop-shaped parts on both sides) and the polarity determination result of the alternating induced voltage of the fine position sense line that gives the maximum value.
The position within the cycle can be detected.

Other Embodiments of Fine Position Detection Circuit The two-signal conversion circuit 192 and the normalization circuit 193 constituting the fine position detection circuit 19 shown in FIG. 2 may be constructed as follows.

The induced voltage V (Sl ) ~ V (34) in Figure 18 (1) (
This characteristic is the same as that shown in FIG. 6 (3).

The two-signal converting circuit 192 calculates the two composite voltage values Vs and Vc as follows: Vs = V(Sl) + V(82)-V(S3)-V(3
4) ・−・・−(22)Vc=V(St)−'V(
S2)-V(S3)+V(S4)-=・(23'') This composite voltage value Vs, Vc has a repetition characteristic of pitch P as shown in FIG. 18(2).At this time, the normalization circuit 193 first calculates the relative magnitude ρ of the composite voltage values Vs and Vc using the above-mentioned equation (10).This normalized value ρ is as shown in FIG. 18 (3).

Therefore, the normalized value ρ is calculated and converted into the 1-position conversion circuit 1.
94. The normalized value ρ varies from 0 to 1 in the small areas A1 to A8 within each period (shown in (6) in FIG. 18) that are equally divided by the width Z by shifting 5 periods 2P as shown in FIG. 18 (4). It becomes a characteristic that changes up to. This is the same as the output of the normalization circuit 193 in the embodiment described above, so the position conversion circuit 1
94, the position ΔX within the loop shape section can be obtained. In addition, the offset value within one cycle X0FF is obtained from the fine position sense line that provides the maximum induced voltage and the polarity determination result for the alternating induced voltage, as in the above-described embodiment,
The added value of X0FF and ΔX is outputted from the fine position detection circuit 19 as the cycle same position XX.

Further, the binary encoding circuit 192 is not limited to calculating the two composite voltage values Vs and Vc based on the induced voltages of all the fine position sense lines as in the above embodiment.

For example, if the fine position sense line that gives the maximum induced voltage obtained from the maximum value fine position sense line detection circuit 195 is S, the induced voltage is VW, to the right of the loop-shaped part of the fine position sense line SwL that gives Vw. The induced voltage of the fine position sense line sR having a loop-shaped portion next to it is vR0, and the induced voltage of the fine position sense line sL having a loop-shaped portion adjacent to it to the left is vL.

Vs ” VR-VL =----
-----------(25) VC: VW-m (VR, VL)
------------- (26) However, m (A, B) indicates the smaller value of A and B.

Even if the two combined voltages are calculated, and the normalized value ρ is calculated in the normalization circuit 193 as Vs (27) Vc. good.

FIG. 19 shows the change characteristics of the aforementioned combination Fy, pressures Vs, Vc, and normalized value ρ.

Figure 19 fi+ shows the loop-shaped part of the fine position sense line, with the fine position sense line 1113m in the center and SL on the left.
, the right side corresponds to the loop-shaped portion of sR. Figure 19 (2
) are the fine position sense lines 5ILK, SL and sR.
The solid line portion corresponds to Vw, VT, , VR used in the above equation.

As shown in the figure, if the induced voltages at the positions of points Bo, B1, and B2 are set as shown in Figure 19 (2), the 8 composite voltage value Vs is determined by the coordinates as shown in Figure 19 (3). As the indicator 4 moves from BO to B2 point -(vb
-Vd) to (Vb-Vd). Also, Vc always has a positive value from (Vb-Vd) to (V
a-Vc) and then change to (Vb-Vd) again. Therefore, the normalized value ρ according to equation (27) is
As shown in Fig. 19 F41K, the change characteristic is -1 at 80 points, O at point B1, and +1 at 82 points. By inputting this normalized value ρ into the 0 position conversion circuit 194, the loop shape section position ΔX can be obtained using a position conversion table previously set based on the characteristics of ρ in FIG. 19 (4). .

Other Embodiments In the embodiments of the present invention shown in FIGS. 1 and 2, each circuit performs processing for coordinate detection based on the output of the A/D converter 14 constituting the induced voltage detection circuit IO. For example, the absolute value conversion circuit 15. Polarity determination circuit 17. Fine position detection circuit 19 constituting the coordinate detection circuit 18. The coarse position detection circuit 20 and the like are constructed of digital circuits that handle digital values and have various functions. However, these digital circuits and control circuit 23 can also be replaced by a microprocessor and a program that controls its operation.

FIG. 20 is a block diagram of another embodiment of the present invention based on this idea.

Items with the same functions as those in Figure 1 are given the same number.

30 is an arithmetic control section, and interface sections 31 and 34
, a microprocessor 32, and a memory 33 (35 is an external device. The induced voltage detection circuit 1.0 includes an amplifier 11, a filter 1l, a sample and hold circuit 13, an A/D converter 14, and It is composed of a peak timing detection circuit 16.

The microprocessor 32 controls the switching circuit 9 and the induced voltage detection circuit 10 at a predetermined timing via the interface section 31 to control the fine position sense line groups 51 and 71.
and the induced voltages of the respective sense lines of the coarse position sense line groups 61 and 81 are taken in, the coordinate values of the coordinate indicator 4 are detected by the above-mentioned algorithm, and the detected coordinate values are outputted via the interface section 34, It is supplied to external equipment 35.

The operation of this microprocessor 32 is controlled by a program stored in memory 33.

The operation of the microprocessor 32 is the same as that of the digital circuit and control circuit 23 described above.

Since the detailed operation and processing have already been described, only the general flow K of the program (shown in FIGS. 21 to 25) defining the operation of the microprocessor 32 will be described here.

FIG. 21 is a general flowchart of the arithmetic control section 30 of the eight embodiments.

The induced voltage capture process 40 is performed by the switching circuit 9 in order to capture the induced voltage of each sense line of the X-axis peripheral and Y-axis fine position sense line groups 51, 71, and coarse position sense line groups 61, 81.
and a routine for controlling the induced voltage ejection circuit 10 at predetermined timing.

The X-coordinate detection process 41 is a routine that detects the X-coordinate value by the induced voltage of the sense line around the X-axis among the induced voltages of each sense line obtained by the induced voltage acquisition process 40, and the X-coordinate detection process 42 is a routine that similarly detects the X coordinate value.

A formatting process 43 converts the obtained X and X coordinate values into a predetermined format, and outputs coordinate data at 44.

This series of processing is repeated at a predetermined period (sampling period).

FIG. 22 shows the flow of the induced voltage capture process 40, and the operation timing corresponds to the timing chart shown in FIG. 9. Therefore, the operation of this flow will be explained with reference to FIG.

Sense line code S ctt+ to be selected at 402
231 is supplied to the switching circuit 9. (timing T2
) Then, by rising and falling the sample and hold control signals 232 at 403, 404 and 405, the sample and hold control signal 23 shown in FIG. 9(4) is
Outputs 2. And at 406, flip-flop 1
The Q output of 63 (shown at i51 K in Figure 9) indicates whether it is in the hold state, and if it is in the hold state (timing T4 in Figure 9), the A/D converter 1
Start 4. Thereafter, a signal (Eoc) indicating the completion of A/D conversion is detected at 408, and the A/D converted induced voltage is stored in a predetermined area of the memory 33 at 4o9. This process is performed for each sense line.

FIG. 23 shows the flow of the X coordinate detection process 41. Components having the same functions as the circuit of the embodiment shown in FIG. To avoid confusion, an S was added at the end of the number. This also applies to the following figures 24 and 25.

This X zachii ejection process 41 is performed by guiding the X-axis circumferential fine position sense line K E (A/DT conversion letter @) v (Sl) ~
Based on V (S4), calculate the 6-cycle inner samurai X in the current position ejection process 19S.1. ．． ．． > Rough layer position for ltl Based on the sense line conductive voltage V (Gi) and xI, determine the periodic reference point position X
c is calculated, and in absolute coordinate value processing 21S, X=Xc+
Addition of X1 is performed to calculate the X coordinate value.

FIG. 24 shows the flow of the fine position detection process 19S.
) than the value.

The phase of the alternating induced voltage given each V (Si) is the excitation alternation.

Determine whether or not it is in phase with the voltage phase, 1 determination result P (Si)
K to store it in a predetermined area of the memory 33.

Depending on the value of P(SL) (15sIcte, V(SL)
17) Calculate e versus value V (No. 8). And 195
At step 8, the fine position sense line Sn that gives the maximum induced voltage is detected based on V (SL), and this sense line number and the corresponding polarity judgment result P (Sn) are stored in a predetermined area of the memory 33. do.

Then, in 192S, this le and v(1) to V(4
), the total Qli [pressures Vs and Vc are calculated by the calculation shown in formulas +71 and +81, and at 193s, (
10) The normalized value ρ shown in equation 10) is calculated, and in step 194S, the intra-loop shape section position movement ΔX is calculated. Also, in 196S, calculate the intra-period offset (+MXorF) using Le and P (SFL) obtained in 1958, and in 1978
By adding 0FF and ΔX, position XI within 0 period
is obtained and stored in a predetermined area of the memory 33.

FIG. 25 shows the flow of the coarse position detection process 20S, in which the coarse position sense line Qm giving the maximum induced voltage in 2018 is detected from each induced voltage of the coarse position sense lines.

Then, in step 2028, it is determined in which periodic region Ast the coordinate indicator 4 is located, based on the coarse position sense line number layer and the periodic self-position X obtained previously in the fine position detection process 19S. Based on the period number N of the determined periodic area ASN, K
At 2038, the reference point position Xc of the one-period area ASN is calculated.

In this embodiment, the digital circuit section is implemented by a microprocessor 32 and a memory 33 that stores a program for controlling the microprocessor 32.
etc., the device can be made smaller and lighter.

〔Effect of the invention〕

According to the present invention, the total number of sense lines for coordinate detection can be increased by increasing the repetition period width of the induced voltage characteristic by a small number of fine position sense wires, and reducing the number of coarse position sense lines due to this expansion. Up to 115 compared to the conventional device of 1.
Since the reduction can be reduced to 1/2 compared to the second conventional device, the switching circuit for connecting each sense line terminal to the induced voltage detection circuit in a time-sharing manner can be used to expand the coordinate reading range and increase the size. It is possible to prevent an increase in scale, an increase in detection time for detecting induced voltages of all sense lines, and a decrease in coordinate reading speed.

In addition, since it is possible to detect without error in which cycle the coordinate indicator is located by using the coarse position sense line group that divides the coordinate reading range into regions with a width of 2P or less of the repetition cycle of the induced voltage characteristics, the coordinate Coordinate detection errors can be prevented even when the reading range is expanded and the size is increased.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, and FIG.
FIGS. 3 and 4 are configuration diagrams of the coordinate detection circuit shown in the figure, and FIG. 5 is a sense line laying pattern diagram of the present invention. FIG. 6 is an explanatory diagram of induced voltage characteristics of the sense line shown in FIG. 3. 7 is an operation timing diagram of the switching circuit in FIG. 1, FIG. 8 is a configuration diagram of the peak timing detection circuit and polarity determination circuit in FIG. 1, and FIG. 9 is an operation timing diagram of the induced voltage detection circuit in FIG. 1. , FIG. 10, and FIG. 11 are explanatory diagrams of the operation of the fine position detection circuit of FIG. 1, and FIG. 12 is a characteristic diagram showing induced voltage characteristics of the sense line of FIG. 4. FIG. 13 is an explanatory diagram of the operation of the rough position detection circuit of FIG. 1. Figure 14 is a block diagram of the period number determination circuit in Figure 2;
16 is a diagram showing the installation pattern of another example of the fine position sense line, FIG. 17 is a characteristic diagram showing the installation pattern and induced voltage characteristics of another example of the fine position sense line, and FIGS. 1
FIG. 9 is an operation explanatory diagram of another embodiment of the fine position detection circuit, the second
FIG. 0 is an overall configuration diagram of another embodiment of the present invention, and FIGS. 21 to 25 are flowcharts showing the arithmetic processing procedure of the arithmetic control section of FIG. 20. 1... Excitation winding drive circuit. 4... Coordinate indicator, 5-8... Flat plate. 51, 71... fine position sense line group. 61, old... coarse position sense line group. 9...Switching circuit, 10...Induced voltage detection circuit. 13...Sample hold circuit. 14...A/D converter. 16...Peak timing detection circuit. 15... Absolute value conversion circuit, 17... Polarity determination circuit. 18... Coordinate detection circuit, 19... Fine position detection circuit. 20... Rough position detection circuit. 191...Sense line data storage circuit. 192... 2-signal conversion circuit, 193... Normalization circuit. 194...Position conversion circuit. 195...Maximum value fine position sense line detection circuit. +96: Intra-period offset value calculation circuit. 201... Maximum value coarse position sense line detection circuit. 202...Period number determination circuit. 203...Cyclic reference point position calculation circuit. 30... Arithmetic control unit. 31, 34...interface section. 32...Microprocessor. 33...Memory, 35...External device. 4','')・, Representative Patent Attorney Katsuo Ogawa-11 2Ab Figure R', p-22 p14゜゜゜/D Figure 5rct2 51%-ISA
Sxv+ 54+20t7. l+c-1#
14 z-22 15 16 19 21 220 23 Figure 24 Second Evening

Claims (1)

[Claims] 1. A plurality of sense lines are laid on a flat plate, and a coordinate indicator that generates an alternating magnetic field is brought close to the flat plate by an excitation alternating voltage supplied from an alternating voltage generating circuit. In a coordinate reading device that determines the position of the coordinate indicator by detecting the magnitude of an alternating induced voltage induced in a sense line by electromagnetic inductive coupling, the coordinate reading device has loop-shaped portions at intervals of a pitch P, and adjacent loop-shaped portions A plurality of micro-position sensing wires made of electrical conductor wires connected so that the directions of current flowing in each section are opposite to each other are shifted in parallel to the detection coordinate axis direction by a predetermined width Z on the flat plate. A coordinate system comprising: a group of fine position sense lines formed by laying a plurality of fine position sense lines; the position of the coordinate indicator is determined based on the magnitude of an alternating induced voltage induced in each fine position sense line; reading device. 2. The micro-position sense wire has one end connected to the micro-position sense wire, and has a return wire made of an electric conductor wire laid in parallel in proximity to the connecting portion between adjacent loops that connects the adjacent loop-shaped portions. The position of the coordinate indicator is determined based on the magnitude of an alternating induced voltage induced between the other end of the fine position sense line and the other end of the return line. Coordinate reading device according to item 1. 3. One end of each micro-position sense wire is one end of a single return wire made of an electrical conductor wire laid parallel to and close to the connecting portion between adjacent loops that connects adjacent loop-shaped portions of the micro-position sense wire. The position of the coordinate indicator is determined based on the magnitude of an alternating induced voltage of each fine position sense line connected to the other end of the fine position sense line and the other end of the return line. A coordinate reading device according to claim 1. 4. In Claims 1, 2, or 3, the fine position sense line group has a loop width of the loop-shaped portion of l, a pitch of P of nl, and a predetermined width of Z of P. 1. A coordinate reading device comprising n fine position sense lines with /n. 5. A plurality of fine position sense wires each having loop-shaped portions at intervals of pitch P and consisting of electrical conductor wires connected so that the directions of current flowing in adjacent loop-shaped portions are opposite to each other are connected to a flat plate. Predetermined width Z above
A group of fine position sense lines are formed by shifting parallel to the direction of the detection coordinate axis; An induced voltage detection circuit detects the magnitude of an alternating induced voltage induced in the fine position sense lines; The fine position sense lines a polarity determination circuit that detects whether the phase of the alternating induced voltage is in phase or opposite to the phase of the excitation alternating voltage; It has a value fine position sense line detection circuit, and detects the value of the coordinate indicator based on the output results of the induced voltage detection circuit, the polarity determination circuit, and the maximum value fine position sense line detection circuit for the fine position sense line group. A coordinate reading device comprising: a fine position detection circuit that detects a position within a period having a period twice the pitch P. 6. In claim 5, the fine position sense line group is composed of four fine position sense lines whose predetermined width Z is P/4 with respect to the pitch P of the fine position sense lines. The fine position detection circuit detects the induced voltages V(1), V(
2) A dual-signal circuit that calculates two composite voltage values VS and VC based on the values of V(3) and V(4), and a dual-signal circuit that calculates the composite voltage values VS and VC obtained from the dual-signal circuit. A normalization circuit that calculates the relative magnitude, a position conversion circuit that converts the output value of the normalization circuit into position information, and a fine position sense line that provides the maximum value among the induced voltages. Based on the maximum value fine position sense line detection circuit, the output of the maximum value fine position sense line detection circuit, and the corresponding output result of the polarity determination circuit, an offset in units of the predetermined shift width Z within the period. It is composed of an intra-period offset value calculation circuit that calculates a value, and an addition circuit that adds the output values of the position conversion circuit and the intra-period offset value calculation circuit, and the period of the coordinate indicator is calculated from the output terminal of the addition circuit. A coordinate reading device characterized by having a fine position detection circuit that outputs a position within. 7. In claim 6, the dual-signal converting circuit has the following formula: VS=V(1)+V(2)-V(3)-V(4)VC=
A coordinate reading device characterized in that it is configured to calculate two composite voltage values VS and VC of V(1)-V(2)-V(3)+V(4). 8. In claim 6, the two-signal conversion circuit calculates VS=V(n)+V based on the fine position sense line number n which is the output result of the maximum value fine position sense line detection circuit. (n+1)-V(n+2)-V(n
+3) VC=V(n)-V(n+1)-V(n+2)+
V(n+3) However, when n is 1 to 4 and 1+i>4,
A coordinate reading device characterized in that it is configured to calculate two composite voltage values VS and VC of n+i=1+i-4. 9. In claim 6, the normalization circuit converts one of the input composite voltage values VS and VC into two of each composite voltage VS and VC.
A coordinate reading device characterized in that the coordinate reading device is configured to output a value divided by the average sum of products (√[VS^2+VC^2]). 10. In claim 5, the fine position detection circuit comprises a fine position sense line that provides the maximum induced voltage obtained by the maximum value fine position sense line detection circuit, and a loop shape of the fine position sense line. Based on each induced voltage obtained by the induced voltage detection circuit of the fine position sense line having a loop-shaped part near the part and the output result of the polarity determination circuit, the period is twice the pitch P of the coordinate indicator. A coordinate reading device characterized by detecting a position within a period. 11. In claim 5, the induced voltage detection circuit is a peak timing detection circuit that detects the timing at which the voltage of the excitation alternating voltage output from the alternating voltage generation circuit reaches a positive or negative peak value. , a sample and hold circuit that holds the alternating induced voltage of the fine position sense line using the output signal of the peak timing detection circuit, and an A/D converter that converts the hold value of the sample and hold circuit into a digital value. A coordinate reading device characterized by: 12. In claim 11, the polarity determination circuit determines the phase of the alternating induced voltage of the fine position sense line depending on whether the output value of the A/D converter is larger than a predetermined value. A coordinate reading device that detects whether the excitation alternating voltage is in phase with or in phase with the phase of the excitation alternating voltage. 13. A micro-position sense wire consisting of an electric conductor wire having loop-shaped portions spaced apart by a pitch P and connected so that the directions of current flowing in adjacent loop-shaped portions are opposite to each other, and are placed on a flat plate. A group of fine position sense lines laid out in parallel to the detection coordinate axis by a predetermined width Z, and a coordinate reading range laid on the flat plate to be divided into regions with a width less than twice the pitch P. a fine position sense line having a coarse position sense line group; an induced voltage detection circuit that detects the magnitude of an alternating induced voltage induced in each sense line of the fine position sense line group and the coarse position sense line group; A polarity determination circuit that detects whether the phase of the alternating induced voltage of the position sense line is in phase or opposite to the phase of the excitation alternating voltage, and a fine position sense line that provides the maximum induced voltage among the fine position sense line group. It has a maximum value fine position sense line detection circuit to detect,
Based on the output results of the induced voltage detection circuit, the polarity determination circuit, and the maximum value fine position sense line detection circuit for the fine position sense line group, the period is twice the pitch P of the coordinate indicator. a fine position detection circuit that detects the position within; detects in which cycle the coordinate indicator is located based on the output results of the induced voltage detection circuit and the fine position detection circuit for the coarse position sense line group; A coordinate reading device comprising: a coarse position detection circuit, and determining the position of the coordinate indicator based on output results of the fine position detection circuit and the coarse position detection circuit. 14. Claim 13, wherein the coarse position sense line group is formed by shifting coarse position sense lines made of loop-shaped electric conductor wires in parallel to the detection coordinate axis direction by twice or less the pitch P. A coordinate reading device comprising a plurality of coarse position sense lines laid on a flat plate. 15. In claim 14, the coarse position sense line group has one terminal of each of the coarse position sense lines connected to a return line made of an electric conductor line laid parallel to the detection coordinate axis, A coordinate reading device characterized in that each of the other terminals is led by an electric conductor wire to the vicinity of a terminal at one end of the return line in parallel with the return line. 16. In claim 13, the coarse position detection circuit is configured to detect the coarse position sense line giving the maximum induced voltage based on the output result of the induced voltage detection circuit for the coarse position sense line group. A cycle number determination circuit that detects in which cycle the coordinate indicator is located based on the output results of the value coarse position sense line detection circuit, the maximum value coarse position sense line detection circuit, and the fine position detection circuit. and a cycle reference point position calculation circuit that calculates the distance from the reference position on the detection coordinate axis of the reference point of the cycle in which the coordinate indicator is located based on the cycle number detected by the cycle number determination circuit, A coordinate reading device characterized in that the position of the coordinate indicator is determined by the sum of output values of the fine position detection circuit and the coarse position detection circuit. 17. In claim 16, the period number determination circuit determines the maximum value using a table in which at least one period number and one period number determination threshold corresponding to each rough position sense line are set in advance. A corresponding cycle number group is obtained based on the output result of the coarse position sense line detection circuit, and a unique cycle number is determined based on whether the output value of the fine position detection circuit is larger than the cycle number determination threshold. coordinate reading device.