JPS61233824A - Position detector - Google Patents

Abstract

PURPOSE:To eliminate a cord from a pen and to improve the operability by arranging plural long magnetic substances each wound with a coil at a prescribed interval in parallel and using the inductance change in each coil so as to detect the position of the pen when the pen approaches. CONSTITUTION:When the pen 20 incorporating a rod magnet is positioned on the magnetic substances 11a-11h, since the angle between the magnetic flux and each magnetic substance in the lengthwise direction is smaller in a magnetic substance closer to the pen, the inductance of the coil of the magnetic substance closest to the pen is minimized. Thus, the inductance of each coil (12a-12h) is converted into a voltage signal by a converting circuit 30 and a signal selection circuit 40, a voltage difference (differential component) among the coils is taken to calculate the coordinate where the difference is zero.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a position specifying magnetic field that is specified by a position specifying magnetic generator based on a change in magnetic permeability of a magnetic body to which a magnetic field is applied by the position specifying magnetic generator. This invention relates to a position detection unit that detects a position.

(Prior Art) As a conventional position detection unit, a pulse current is applied to a drive coil provided at one end of a magnetostrictive transmission medium or at the tip of a position indicating pen to generate magnetostrictive vibration waves in the magnetostrictive transmission medium. Then, the time required to detect the induced voltage based on the magnetostrictive oscillation waves in the detection coil provided at the tip of the positioning pen or one end of the magnetostrictive transmission medium is measured using a processor, etc., and from this, the indicated position of the positioning pen is determined. There was something I did as if I had calculated it. In addition, as another conventional position detection device, a plurality of drive lines and detection lines are arranged perpendicularly to each other, and the induced voltage is detected by sequentially passing current through the drive lines and sequentially selecting the detection lines. There was a device in which a position specified by a position indicating pen made of a magnetic material such as ferrite was detected from the position of a detection line where a large induced voltage was induced.

(Problem to be solved by the invention) The former device has relatively good position detection accuracy, but in order to send and receive timing signals etc. between the pen and the processor, a code is required between the pen and the device. In addition to being susceptible to induction from other devices, it may cause malfunctions or even become a source of noise; It had to be held and directed fairly close. In addition, in the latter device, the positioning pen can be cordless, but the resolution of the coordinate position is determined by the line spacing, and if the line spacing is reduced to increase the resolution, the SN
The ratio and stability deteriorate, so it is difficult to increase the resolution, and it is also difficult to detect the position directly above the intersection of the drive line and detection line. It was impossible to use it because it had to be placed close to the input surface and a thick object was placed on the input surface. Furthermore, conventionally, when trying to associate the timing of position input with pen operation,
It is necessary to attach a switch or some kind of signal generating circuit to the pen itself, resulting in a complicated structure and problems such as being prone to failure.

The present invention improves these conventional drawbacks, and
To provide a highly accurate position detecting part that has good operability without having a position specifying magnetic generator connected anywhere, is strong against external guidance, and does not emit noise.

(Means for Solving the Problems) As shown in FIG. 1, the position detection unit of the present invention includes a plurality of elongated magnetic bodies 11a to 11h arranged substantially parallel to each other at predetermined intervals, and a position detection unit 10 including a plurality of coils 12a to 12h wound over a wide range of each of a plurality of magnetic bodies 118 to 11h; a position designating magnetic generator that generates a steady magnetic field; For example, an input pen 20, a conversion circuit 30 that converts the inductance of a coil into an electrical signal, a signal selection circuit 40 that switches and connects the conversion circuit 30 and the plurality of coils 12a to 12h of the position detection section 10, and the signal The electrical signals corresponding to the inductances of the plurality of coils 12a to 12h are taken out one after another via the selection circuit 40, the difference between them is taken, and the position where the difference voltage becomes equal to a predetermined reference voltage is calculated,
A position detection circuit 50 which calculates the specified position on the position detection unit 10 by the input ben 20 from this, calculates the slope of the differential voltage, and calculates the height of the input ben 20 with respect to the position detection unit 10 from this. It consists of

(Function) When the inductance L of the coils 12a to 12h is expressed by the formula, L=μ·SN2/1 (where, S is the cross-sectional area of the magnetic material, N is the number of turns of the coil, and 1 is the magnetic (It is the length of the body.)

Here, since S, N, and 1 are determined by the specific configuration of the position detecting section 10 and can be assumed not to change, the inductance L is proportional to the magnetic permeability μ of the magnetic bodies 118 to 11h.

By the way, the magnetic permeability μ of the magnetic bodies 118 to 11h is determined by a steady magnetic field (hereinafter referred to as magnetic bias) applied from the outside.
varies greatly depending on The state of the change varies depending on the composition of the magnetic material, the frequency of the alternating current, or whether the magnetic material is subjected to heat treatment or magnetic field treatment, but here, as shown in Figure 2, when a slight magnetic bias is applied, It is assumed that it is the maximum, and the more magnetic bias is applied, the more it decreases.

When one end 20a of the input pen 20 containing a built-in bar magnet is positioned above the magnetic bodies 118 to 11h, the one end 20a is attached to the magnetic bodies 118 to 11h as shown in FIGS. 3 and 4.
The magnetic fluxes coming out from 0a intersect. At this time, the angle at which the magnetic flux intersects the longitudinal direction of each of the magnetic bodies 11a to 11h is at the same distance from the one end 20a as the center.
The closer the magnetic material is to 0a, the smaller the magnetic material is, and the farther away from the one end 20a the larger the magnetic material is. The magnetic bias opening applied to the magnetic bodies 118 to 11h becomes larger as the angle at which the magnetic flux intersects with the longitudinal direction of the magnetic bodies 11a to 11h becomes smaller. ,
The further away the magnetic material is from this point, the smaller it becomes.

Therefore, as shown in FIG. 3, when one end 20a of the input pen 20 is brought into contact with the input surface 100 formed on the upper part of the position detection section 10, the inductance of each coil will change at the position where the input pen 20 is placed. The inductance of the magnetic coil closest to is set to the minimum value, and increases gradually as you move away from this point.

Here, it is possible to directly fill the inductance L with water, but the subsequent processing is difficult, so the conversion circuit 30 and the signal selection circuit 40 convert the inductance L of each coil 12a to 12h into an electrical signal. For example, convert it into voltage. FIG. 5 shows the voltage value V corresponding to the inductance L of each coil 12a to 12h. -v7, the horizontal axis is the magnetic material 1
The coordinate positions in the direction perpendicular to 1a to 11h (hereinafter referred to as the X direction) are shown, and the vertical axis shows the voltage value.

Here, the coordinate values Xo to x1 indicate the positions of the respective coils 12a to 12h in the X direction. The position detection circuit 50 extracts each voltage V - V7 through the signal selection port 40, and calculates the X coordinate value at which the voltage value becomes the minimum value by calculating the coordinate value of the designated position of the input vent 20. X can be found.

As a method for determining the coordinate value X, there is a method of approximating the waveform near the minimum value in FIG. 5 by an appropriate quadratic function and determining the X coordinate value of the minimum value of the function. Also, there are various ways to find the X coordinate of the minimum value of a function, but focusing on the fact that the difference is "0" at the minimum value (the same applies to the maximum value), we create a difference equation for the function, The coordinate position where the difference is "0" is calculated, and from this the coordinate value X of the minimum value can be determined.

Each conversion voltage V. -v7, the difference (difference in voltage value), that is, (V-Vo>, (v2-v>, (v
3-v2), ...... (V7-V6), the differential voltage values v1, ■2, ■3, .
...■7 is obtained. In Figure 6, the horizontal axis is
The coordinate position in the direction is shown, and the vertical axis shows the voltage value. However, here, the difference "0" is set to a predetermined positive reference level ■1. In the figure, it can be seen that the voltage value crosses the reference V level between v3 and ■4, and the difference between them is "0".

Further, even if the input pen 20 is moved along the magnetic bodies 118 to 11h, the amount of magnetic bias applied to each magnetic body does not change, so the same coordinate value XS can be obtained.

Furthermore, by combining two position detection units 10 orthogonal to each other, so-called two-dimensional coordinate values in the X and Y directions can also be determined.

On the other hand, in order to specify the position, it is sufficient to locally apply a magnetic bias of several Oe to the magnetic bodies 118 to 11h, so the input pen 20 is placed higher than the magnetic bodies 11a to 11h.
) can also be used with some separation in the direction.

As shown by the broken line in FIG. 3, when one end 20a of the input pen 20 is separated from the input surface 100 by a height h, the angle at which the magnetic flux intersects the longitudinal direction of the magnetic material at a distance from the one end 20a There is no major change, and the amount of magnetic bias applied to the magnetic body also does not change, but in the magnetic body directly below one end 20a, the angle at which the magnetic flux intersects with the longitudinal direction of the magnetic body increases overall, so the amount of magnetic bias is also small. Therefore, the magnetic permeability, that is, the inductance becomes large, and the voltage value becomes large.

In FIG. 5, the voltages V' to V7' are
Conversion (detection) when one end 20a is held at the above position at a short distance (for example, about 5 ml) in seven directions
Indicates voltage. The detection voltage V −V7 and the detection voltage V.

-~v7-, it decreases considerably near the designated position, but as you move away from the designated position, the degree of separation decreases, and the curve of the curve is gentle, that is, the difference is decreasing. I understand.

Detection voltage V. ′ to v7″, when the differences are calculated in the same way as above, the differential voltage value V ′ as shown in FIG. 7 is obtained.
, ■2', ■ -1...V7- are obtained. As can be seen from FIGS. 6 and 7, a decrease in the difference appears as a decrease in the slope of the line that crosses the reference level (1), and the two are approximately proportional. That is, the height h is proportional to the slope of the difference between the detected voltages. Therefore, the relationship between the height h and the slope of the difference is determined in advance, and each of the voltages V is determined by determining the relationship between the height h and the slope of the difference. ~
By determining the difference from v7 and further determining its slope, the height h of the input pen 20 can be calculated.

Further, when specifying the input position, it is necessary to input a predetermined timing signal to the position detection circuit 50, but using the height of the input ben 20 as a parameter, for example, the height of one end 20a of the input ben 20 is 0 for input surface 100
．． 5a! When the value becomes 1 or less, the timing signal can be generated, and in this case, the input pen 20
It is sufficient to provide only a bar magnet.

Next, select the X coordinate value for which the difference is actually rOJ, for example x
1. Expressions for determining the coordinate value X and the height h in the two directions will be described. First, each detected voltage, for example, V(x), is expressed by a general formula of a quadratic function as shown in the following formula.

V (x')-ax2+bx+c -...
・(1) If the interval between each coil 12a to 12h (substantially corresponds to the interval between each magnetic body 11a to 11h) is d, then the difference equation ΔdV(x) is JdV (x)=(V (x+d )-V (x))/
d...(2). Therefore, AdV (x-d) = (V (x)-V (x-d)
)/d ・・・・・・(3). (3
) by substituting the above equation (1) into the equation and rearranging it, we get AdV (x
-d)-8((2x+b/a)-d)...(4
) becomes. By the way, the X coordinate value x (ll) satisfying 1icJV (x-d) = O is Xq
= −b/2 a+d/2 −(S).

Since the coordinate value of the vertex of the function is X, eV (X
)/49X-2ax +b=QS,', X,--b/2a...
...(6). Substituting the above equation (5) into equation (6) and rearranging, x, -xq-d/2...
...(1). That is, AdV (X-d) is O
By finding the X coordinate value X of the point where , and subtracting d7/2 from it, the coordinate X of the vertex of the function can be found.

Next, consider the coordinate value XQ. The coordinate value XQ at which AdV (x-d) is 0 is the reference level V in FIG.
The difference voltage value before and after ■ is between 3 and v4 and [ (between the coordinate values x3 and x4), so the above (4
) From the formula, v3-a ((2x3+b/a)-d)-=(8)v
a - a ((2x 4+ b / a) d)
・"・" (9), rearranging this, v3-v4=2a (x3-x4) ;, 2 a-(v v ) / (X3Xa
)x 3-x a =-d, so 2 a=
−(v−v)/d=(1
0). Here, since 2a indicates the slope of the difference curve, the height h in the Z direction is h = A I
2 a l −・−・・＜11
) is obtained from the formula. Note that A is a proportionality constant,
Required experimentally. FIG. 8 shows an example of the relationship between a and the height h of the input pen 20 in seven directions, where h=o(s+
) shows the change in a with respect to h when a is set to 1.

Also, from the above equation (6) of the detection voltage, b/a-d--2xq -・----C1
2), so by substituting this into equations (8) and (9) above, v -2a (x3-xq) ・
...(13)■ =2a(x4-Xq)
...(14). Furthermore, (13), (
14) By dividing both sides of the equation, we get v /v −(x −x ) / (X4−X
, )3 4 3 q. Putting v 3/ v i, = 8 and rearranging, x - (x3-Bx4)/ (1-8)...
...(15) becomes. Since the coordinates X 3 and X 4 are known,
can be determined from the ratio of v3 and ■4, and furthermore, the coordinate X of the vertex can be determined from equation (7).

(Example) FIG. 9 is a partially cutaway view showing a specific configuration of the position detecting section 10, and FIG. 10 is a sectional view taken along the line A-A in FIG. 9. The magnetic bodies 11a to 11h are materials that are difficult to be magnetized even when a magnet is brought close to them, that is, have a small coercive force, and have high magnetic permeability, such as amorphous wires with a circular cross-section and a diameter of approximately 0.1 ms+. Each magnetic body 118-1
1h are arranged in parallel with each other at a predetermined interval (about 5 shoes). In addition, as an amorphous wire, for example (
Fe, -XCOx)75S11°B15 (atomic%) (x
indicates the ratio of Fe and co, and takes a value of 0 to 1. ) etc. are used. The magnetic bodies 11a to 11h are cylindrical insulating members, such as Envir tubes 13a to 1.
Each is housed inside the 3h. Coil 12a~
12h is wound around the surface of the envire tubes 138 to 13h. The coils 128 to 12h are all wound in the same direction (left-handed in this embodiment), one end of each is commonly connected to the conversion circuit 30, and the other end is connected to the signal selection circuit 40. The position detection unit 10 made of these magnetic materials, Envira tube, and coil is fixed inside a non-magnetic metal case 14 with an adhesive or the like. Further, the top of the metal case 14 is covered with a lid 15 made of non-magnetic metal.

FIG. 11 is a sectional view showing a specific example of the input pen 20;
The figure is its electrical circuit diagram. In the figure, reference numeral 21 is a pen-shaped container made of synthetic resin or the like, and a tapered bar magnet 22 is housed in one end of the pen-shaped container so as to be slidable in the axial direction.

Further, an infrared transmitting window 23 made of transparent plastic or the like is provided along the circumferential direction on the other end side of the container 21, and inside the window 23 is a reflector 24 having a conical circumferential surface coated with chrome plating or the like. An infrared light emitting diode 25 is housed therein. 26a and 26b are operation switches, and the operation switch 26
a is attached to one side of the tip side of the container 21, and an operation switch 26b is attached opposite to the other end of the bar magnet 22. Further, 27 is a signal generation circuit, 28 is a battery, and the container 2
It is stored in the appropriate place within 1. The signal generation circuit 27 performs a plurality of (
The device converts three types of commands into a plurality of code signals by combining several pulse signals, and includes a decoder 27a, a code signal generator 27b, and a diode driving transistor 27C, and an operation switch 26a.
, 26b, a code signal is generated to drive the light emitting diode 25. Then, when the operation switch 26a is turned on, an infrared signal indicating a code to start measurement is transmitted via the diode 25J, the reflector 24, and the transparent window 23, and is directly input to the tip of the bar magnet 22 with the cover 29 attached. When pressed against a surface, the bar magnet 22 slides, turning on the switch 26b, and an infrared signal indicating a position input code signal is transmitted.

FIG. 13 shows a specific example of the conversion circuit 30, and in the figure,
31 is an integrating circuit, 32 is a band pass filter, and 33 is an arithmetic circuit. The integrating circuit 31 receives at its input terminal 34 a positive pulse (or a frequency-divided pulse) from an arithmetic processing circuit of a position detecting circuit 50 to be described later, integrates the pulse, and converts it into a triangular wave signal. Band pass filter 32
Then, the triangular wave signal is converted into a sine wave signal and sent to the arithmetic circuit 33. The operational circuit 33 includes an operational amplifier 3
3a, a resistor 33b, and a capacitor 33C.The sine wave signal is input to the inverting input terminal of the operational amplifier 33a via the resistor 33b, and a capacitor is connected between the inverting input terminal and the output terminal. 33C, is connected,
Furthermore, the non-inverting input terminal is grounded. Further, one of the coils 128 to 12tl is connected in parallel to the capacitor 33c via a signal selection circuit 40 composed of a well-known multiplexer or the like, thereby forming a parallel resonant circuit.

Here, the frequency f of the sine wave signal is the resonant frequency of the parallel resonant circuit. (-1/2π-ra> (However, L is the inductance of each coil when no magnetic bias is applied to the magnetic material, and C is the capacitance value of the capacitor 33c.) At this time, the parallel resonant circuit The absolute value +21 of the impedance 2 of is the maximum, but as is well known, the absolute value 121 decreases when C changes. Therefore, a magnetic bias is applied to the magnetic body by the input pen 20, and the inductance L decreases. The absolute value +21 of the impedance of the parallel resonant circuit including the coil also decreases.

On the other hand, the resistance value of the resistor 33b is R1, the input voltage of the arithmetic circuit 33 is V, and the output voltage is ■. ut and 1n, it becomes v out x - (Z / R1) ·■in.

Here, if R1 and io are constant, the output voltage V.

ut will depend on the impedance Z. As mentioned above, when the inductance L of the coil decreases, the impedance z1, that is, the absolute value +21, also decreases, and therefore the output voltage . ut also decreases. In other words, the decrease in inductance L causes the output voltage to decrease. 1. can be detected as a decrease in Note that the reason for using the O-clock pulse as the reference (input) signal is to synchronize with the position detection circuit 50.

FIG. 14 is a circuit block diagram showing a specific configuration of the position detection circuit 50, and FIG. 15 is a diagram showing signals of each part. When an infrared signal indicating a measurement start code is emitted from the light emitting diode 25 of the input vent 20 mentioned above, the infrared signal is received by the infrared receiving diode 51, and is further amplified and waveform-shaped by the receiver 52, and is converted to the original signal. It is converted into a code signal and then returned to a measurement start command signal, which is sent to the input buffer 15.
Sent on 3rd. The arithmetic processing circuit 54 is an input buffer 53
When the command signal is read and the start of measurement is recognized,
A switching signal S1 is sent to the signal selection circuit 40 via the output buffer 55, and the connection between the conversion circuit 30 and the coils 12a to 12h is switched one after another.

Each coil 12a to 1 converted by the conversion circuit 30
The voltage corresponding to the inductance of 2h is amplified by an amplifier 56, further rectified by a detector 57, converted into a DC voltage detection signal S2, and further sent to a difference detection circuit 58, where it is converted to a difference detection signal $5. (However, since this difference detection signal S5 needs to be converted into a digital value, it is level-shifted so that it becomes a unipolar, here positive voltage signal.) Note that the difference detection circuit 58 includes an 80-channel control circuit 54.
Two sampling pulses 33.8 as described further below.
4 is input via the output buffer 55. The difference detection signal S5 is sent to an analog-digital (A/D) converter 5.
9, it is converted into a digital value and sent to the arithmetic processing circuit 54 via the input buffer 53;
Then, the digital value is read in synchronization with the switching signal.

Further, the arithmetic processing circuit 54 temporarily stores each of the differential voltage values (digital values) in the memory 60, and selects the largest voltage value among the voltage values smaller than the reference level (1), and (2) the larger voltage value. the smallest of the values,
That is, the voltage values ①, v, and +1 before and after that are detected. Next, in the arithmetic processing direction, a path 54 extracts the voltage value vk''k++ and its X coordinate values x and xk+1 from the grid 60, and converts them into voltages V3 and Vt in equation (15), respectively.

X3. As X4, the calculation process of equation (15) is performed to obtain the coordinate value X 2 , and the calculation process of equation (7) is further performed to obtain the coordinate value X 2 . In addition, the height h is determined by calculating equation (11) as necessary.

The X coordinate mx of the digital value obtained in this way
(or coordinate value X, and height h) is -d, memory 60
However, while the signal indicating the start of measurement is being issued, the above-mentioned measurements and calculations are repeated at predetermined intervals, and the values are updated. Next, an infrared signal indicating a position input code is transmitted from the input pen 20, and when it is recognized by the arithmetic processing circuit 54 via the light receiving diode 51, receiver 52, and input buffer 53, the The X coordinate value of the digital value is sent as an input value via an output buffer 61 to a digital display (not shown) for display, or sent to a computer (not shown) for processing, or a digital-to-analog (D/
A) Converted to an analog signal via converter 62 and processed.

FIG. 16 shows a specific circuit of the difference detection circuit 58. The detected signal S2 is sent from the input terminal 58a to multiplexers 58b and 58C. A reference level sampling pulse S3 is supplied to the multiplexer 58b from the arithmetic processing circuit 54, and during the high level period of the pulse, the voltage of the detection signal S2 is held in a sample hold circuit 58d consisting of a capacitor C1 and an operational amplifier OP1. Similarly, the differential level sampling pulse S4 is supplied to the multiplexer 58C from the arithmetic processing circuit 54, and during the high level period of this pulse, the detected signal S4 is supplied to the multiplexer 58C.
2 voltage is held in a sample hold circuit 58e consisting of a capacitor C2 and an operational amplifier OP2. The voltages held in the sample and hold circuits 58d and 58e are input to a differential amplifier 58f, and a difference detection signal S5 corresponding to the difference is sent out from an output terminal 58Q.

In the embodiments described above, signals indicating the start of measurement, position input, etc. were transmitted from the manual pen 20 to the position detection circuit 50 using infrared signals, but ultrasonic signals may also be used. Furthermore, since these signals are simply used to make the arithmetic processing circuit 54 recognize the timing of the start of operation of the position detection circuit 50 and the input of coordinate values, they do not particularly need to be sent from the input vent 20; The signal may be sent from a keyboard or other switch circuit provided in the circuit 50 itself.

Furthermore, the height of the input ben 20 can also be used as a parameter for position input. That is, a signal to start measurement is sent from the keyboard or other switch circuit, and in this state, one end of the input ben 20 is pressed in the input direction 100 of the position detection section 10, and the height h is set to a predetermined value, for example, 0.5 m as described above. When the value is below, the arithmetic processing circuit 54 detects this and recognizes it as a position input signal.

Figure 17 shows the input vent 70 used at this time.
At one end 72 of a pen shaft-shaped container 71 made of synthetic resin or the like,
A tapered bar magnet 73 is housed with the N pole facing toward the tip, and a cover 7 made of plastic or the like is roughly placed at the tip of the bar magnet 73.
4 is installed. Therefore, there is no need to provide the input pen 70 itself with an electric circuit or battery as described above, and it is possible to input a position in conjunction with the operation of the input pen 70, so that operability does not deteriorate.

In addition, the number of magnetic bodies and coils in the examples is an example,
Needless to say, it is not limited to this. Further, it has been confirmed through experiments that position detection can be performed with relatively high accuracy if the spacing between the magnetic bodies is about 2 to 61 degrees. Also,
The position specifying magnetic generator is not limited to a permanent magnet, but may also be an electromagnet.

FIG. 18 shows a further embodiment of the present invention. In the figure, reference numerals 81 and 82 indicate position detection units in the X and Y directions, and 83 and 84 indicate signal selection circuits for the X and Y directions, which have the same configuration as the position detection unit 10 and the signal selection circuit 40, respectively. (However, the details are omitted in the drawing for simplicity.), and the position detecting section 81.8
2, the respective magnetic bodies are superimposed on each other so as to be orthogonal to the X direction and the Y direction, respectively.

A position detection circuit 85 is similar to the position detection circuit 50 except that position detection in the X direction and the Y direction is performed alternately. Therefore, according to this embodiment, in two directions, the X direction and the Y direction, and if necessary, in the Z direction.
Direction position (coordinates) can be detected easily. In this case, Z
The position detection in the direction may be obtained from a signal from either the X-direction position detection section 81 or the Y-direction position detection section 82. Note that the configurations of the position specifying magnetic field generator and the conversion circuit may be the same as in the previous embodiment.

(Effects of the Invention) As explained above, according to the present invention, since the differential detection method is adopted as the position detection method, it is possible to improve the position detection accuracy, and it is also possible to detect the position in the height direction. The height of the magnetic generator relative to the position detecting section can be used as a parameter for timing detection when specifying a position, and the position specifying magnetic generator itself does not require an electric circuit or battery, and the position specifying magnetic generator It becomes possible to specify the position in relation to the operation. In addition, since the coil is wound over the entire area around the magnetic material, the inductance of the coil can be increased, that is, the converted voltage can be increased, and the output change of the voltage can also be increased. It becomes possible to take a larger range. Furthermore, since it is sufficient to provide only one type of coil for each magnetic body, the configuration of the position detection section can be simplified. In addition, since there is no need to transfer signals between the magnetic generator for position specification and other devices for position detection, it can be made cordless, and furthermore, the magnetic bias required for position specification is The number is the number Ørsted (
Oe), so the position specification magnetic generator can specify the position even if it is a little away from the position detection part, and it is also possible to specify the position from the back side of the position detection part. can also be placed on the input surface. Furthermore, if the position detection unit is provided in the X direction and the Y direction, the height may be increased in two directions, the X direction and the Y direction, or in addition to these,
There are advantages such as position detection in three directions.

[Brief explanation of drawings]

The drawings serve to explain the present invention. Fig. 1 is an explanatory diagram showing the main structure of the present invention, Fig. 2 is a characteristic diagram of magnetic bias versus magnetic permeability, and Fig. 3 is a diagram from a magnetic generator for position specification. A diagram showing the state of magnetic flux applied to a magnetic body. Figure 4 is a diagram similar to Figure 3 seen from above the magnetic generator for position designation. Figure 5 is an example of the voltage value corresponding to the inductance of the coil. 6 is a graph showing an example of the differential voltage value, FIG. 7 is a graph showing another differential voltage value, and FIG. 8 is a graph showing the relationship between the differential voltage value and the height of the magnetic generator for position specification. A graph showing an example, FIG. 9 is a partially cutaway plan view showing the specific configuration of the position detection unit 10, FIG. 10 is a sectional view taken along the line A-A in FIG. 9, and FIG. 11 is an input pen 12 is an electric circuit diagram thereof, FIG. 13 is a circuit diagram showing a specific configuration of a conversion circuit, and FIG. 14 is a circuit diagram showing a specific configuration of a position detection circuit. Block diagram, Figure 15 is the 14th
16 is a circuit diagram showing the specific configuration of the difference detection circuit, FIG. 17 is a cross-sectional view showing another embodiment of the input pen, and FIG. 18 is a diagram showing the specific configuration of the difference detection circuit. It is an explanatory view showing other examples. 10... Position detection unit, 20... Input pen, 30...
- Conversion circuit, 40... Signal selection circuit, 50... Position detection circuit, 11... Magnetic body, 12a to 12h... Coil, 81... X direction position detection unit, 82... Y Directional position detection section. Patent applicant Wacom Co., Ltd. Patent attorney Furu 1) Sei Takashi Figure 2 3000'. Figure 3 Figure 5 111 禮n ”1btE1notjmJfcJI

Claims (2)

[Claims] (1) Position detection comprising a plurality of elongated magnetic bodies arranged substantially parallel to each other at predetermined intervals, and a plurality of coils wound around each of the plurality of magnetic bodies over a wide range. a position-specifying magnetic generator that generates a steady magnetic field; a conversion circuit that converts the inductance of the coil into an electrical signal; and a signal selection that switches and connects the conversion circuit and the plurality of coils of the position detection section. circuit and the signal selection circuit to sequentially extract electrical signals corresponding to the inductances of the plurality of coils, calculate the difference between them, and calculate the position where the differential voltage is equal to a predetermined reference voltage,
From this, the specified position on the position detecting section by the position specifying magnetic generator is determined, and the slope of the differential voltage is calculated, and from this, the position of the position specifying magnetic generator with respect to the position detecting section is determined. A position detection unit consisting of a detection circuit. (2) A plurality of elongated X-direction magnetic bodies arranged substantially parallel to each other at predetermined intervals, and a plurality of X-direction magnetic bodies wound over a wide range for each of the plurality of X-direction magnetic bodies. an X-direction position detection section having a coil in the X-direction;
A Y-direction position detecting section that has the same configuration as the direction position detecting section and is superimposed thereon, a position specifying magnetic generator that generates a steady magnetic field, and a conversion circuit that converts the inductance of the coil into an electrical signal. , an X-direction and Y-direction signal selection circuit that switches and connects the conversion circuit and a plurality of coils of the X-direction and Y-direction position detection section, and the X-direction and Y-direction signal selection circuits The electric signals corresponding to the inductance of a plurality of coils in the direction and the Y direction are taken out one after another, the difference between them is taken, and the position where the difference voltage is equal to a predetermined reference voltage is calculated, and from this, the position specifying magnetism is generated. The designated position on the position detection unit in the X direction and Y direction by the device is determined, and the slope of the differential voltage in the X direction or Y direction is calculated, and from this, the position of the position designating magnetic generator in the X direction or Y direction is calculated. A position detection device comprising a position detection circuit that determines the height relative to a position detection unit.