JPS61237122A - Position detecting device - Google Patents

Abstract

PURPOSE:To suppress the generation of noise without connecting a position designating magnetic generator, to detect a position with a high accuracy with simple constitution, and also to detect a position in the height direction, by adopting a difference detecting system as a position detecting method. CONSTITUTION:Plural magnetic substances 11a-11h are arranged in parallel and at a prescribed interval in a position detecting part 10, and the first coil 12 which has been connected in series, and the second coils 13a-13h which are independent, respectively are wound around each magnetic substance 11a-11h, respectively. To the coil 12 of this detecting part 10, an alternating current of a prescribed period is supplied from a driving power source 30, and an inductive voltage which has been induced in the coils 13a-13h is fetched to a position detecting circuit 40. Also, an alternating current is switched and applied to each of the coils 13a-13h from a power source 20, an inductive voltage fo the coil 12 is fetched successively, and a position where these difference voltages become equal to a reference voltage is calculated. In this way, a magnetic field from an input pen 20 which is not connected to the detecting part 10 is detected with a high accuracy by a difference detecting system.

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. The present invention relates to a position detection device for detecting a position.

(Prior Art) As a conventional position detection device, a pulse current is applied to a drive coil provided at one end of a magnetostrictive transmission medium or the tip of a position indicating pen to generate magnetostrictive vibration waves in the magnetostrictive transmission medium. , the time required for detecting the induced voltage based on the magnetostrictive oscillation waves in the detection coil provided at the tip of the positioning pen or at one end of the magnetostrictive transmission medium is measured by a processor, etc., and from this the indicated position of the positioning pen is calculated. There was something I did. In addition, as another conventional position detection device, a plurality of drive lines and detection lines are arranged perpendicularly to each other, and current is sequentially applied to the drive lines and detection lines are sequentially selected to detect induced voltage. There is a device in which a position specified by a position indicating pen made of a magnetic material such as ferrite is detected from the position of a detection line where a large induced voltage is 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
It is an object of the present invention to provide a highly accurate position detecting device that has good operability because a magnetic generator for specifying a position is not 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 device 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 first coil 12 wound over a wide range and connected in series for each of the magnetic bodies 11a to 11h;
The second coils 13a-13 are coiled 5 times over a wide range for each of 1a to 11h and each is independent.
h, a magnetic generator for position designation that generates a steady magnetic field, for example, an input pen 20, and an alternating cycle of a predetermined period in the first coil 12 or the second coils 13a to 13h. A driving current source 30 that supplies current, and extracting induced voltages induced in each of the second coils 13a to 13h when the alternating current of the predetermined period is constantly applied to the first coil 12, or 138-13
When the alternating current of the predetermined period is switched and applied to each of h, the induced voltage induced in the first coil 12 is taken out one after another, and the difference between them is taken, and the difference voltage becomes equal to the predetermined reference voltage. The position is calculated, and from this the specified position on the position detection unit 10 by the input pen 20 is determined, and the slope of the differential voltage is calculated, and the height of the input pen 20 with respect to the position detection unit 10 is determined from this. It consists of a position detection circuit 40.

(Operation) An alternating current (
When a sine wave (for example, a sine wave, etc.) is caused to flow, a magnetic flux (magnetic field) is generated around it, and an induced voltage is generated in each of the second coils 138 to 13h due to electromagnetic induction due to this magnetic flux. Since this electromagnetic induction occurs via the magnetic bodies 11a to 11h, the larger the magnetic permeability μ of the magnetic bodies 118 to 11h, the greater the voltage value of the induced voltage. Expressing this in a formula, the induced voltage V is: V-L (di/dt)-μ・SN2/J (di/dt
) (where, S is the cross-sectional area of the magnetic material, N is the second
The number of turns of the coil, ! is the length of the magnetic material. ). Here, since S, N, and j are determined by the specific configuration of the position detecting section 10 and can be assumed not to change, the induced voltage V is proportional to the magnetic permeability μ of the magnetic bodies 11a to 11h.

By the way, the magnetic permeability μ of the magnetic bodies 11a 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, etc.
Here, as shown in FIG. 2, it is assumed that it reaches a maximum when a slight magnetic bias is applied, and decreases as more magnetic bias is applied.

When one end 20a of the input pen 20 containing a built-in bar magnet is positioned above the magnetic bodies 11a to 11h, the one end 20a is attached to the magnetic bodies 11a 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 with the longitudinal direction of each magnetic body 118 to 11h at an equidistant location centering on the one end 20a is
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 amount of magnetic bias applied to the magnetic bodies 11a to 11h increases 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 applied to the input surface 100 formed on the upper part of the position detection section 10, the second coils 13a to 13h have the fifth coil. As shown in the figure, the induced voltage of the second coil wound around the magnetic material closest to the position where the input ben 20 is placed (designated position) is taken as the minimum value, and the voltage V − that gradually increases as the distance from this position increases. V7 occurs. In FIG. 5, the horizontal axis indicates the coordinate position in the direction perpendicular to the magnetic bodies 11a to 11h (hereinafter referred to as the X direction), and the vertical axis indicates the voltage value. Here, the coordinate value X 6 ”'
7 indicates the position of the second coils 13a to 13h in the X direction. Each voltage V in the position detection circuit 40. -v7 and calculate the X coordinate value at which the voltage value becomes the minimum value by calculation, the coordinate value X of the designated position of the input pen 20 can be determined.

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 by 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 rOJ is calculated, and from this the coordinate value X of the minimum value can be determined.

For each induced voltage vo-v7, the difference (difference in voltage value), that is, (V, -Vo>, (v2-vl), (v3
-v2), ...... (V7-V, 6), the differential voltage values ■1, ■2, v3, etc. as shown in Fig. 6 are calculated.
...' V 7 is obtained. In FIG. 6, the horizontal axis shows the coordinate position in the X direction, and the vertical axis shows the voltage value. However, here, the difference numerator OJ is set to a predetermined reference level V of a positive value,
It is set to . In the figure, between ■3 and v4, the voltage value crosses the reference level ■, 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 X is 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, locally several Oe8! Since it is only necessary to apply a magnetic bias of 1.5 degrees, the input pen 20 can be used at a height higher than the magnetic bodies 11a to 11h and somewhat separated from them in the Z) 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. As a result, the magnetic permeability increases and the voltage value increases.

In FIG. 5, the voltages V' to V7' are
The graph shows the rust conduction (detection) voltage when one end 20a of is held at the above-mentioned position at a short distance (for example, about 5 feet) in the Z direction. The detection voltage v −■ and the detection voltage v0′~
Comparing with v7', there is a considerable decrease near the designated position, but the further away from the designated position the less the degree of change, and the curve of the curve is gentle, that is, the difference is decreasing. Recognize.

When the differences are calculated for the detected voltages V' to V7' in the same manner as described above, the differential voltage value v as shown in FIG. 7 is obtained.
-, v '', v -1-...■1- are obtained. As can be seen from Figures 6 and 7, the decrease in the difference appears as a decrease in the slope of the line that crosses the reference level Vt. ,
The two are almost in a proportional relationship. That is, the height h is proportional to the slope of the difference between the detected voltages. Therefore, by determining the relationship between the height h and the slope of the difference in advance, determining the difference from each of the voltages v0 to v7, and further determining the slope, the height h of the input pen 20 can be calculated. can.

Further, when specifying the input position, it is necessary to input a predetermined timing signal to the position detection circuit 40, but using the height of the input pen 20 as a parameter, for example, the height of one end 20a of the input pen 20 is 0 for input surface 100
．． The timing signal can be generated when the voltage becomes 5aw* or less, and in this case, the input pen 20
It is sufficient to provide only a bar magnet.

Next, find the xma value for which the difference is actually “0”, for example x
1. The formula for determining the coordinate value X and the height h in the Z direction 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) -aX +bx+c ---・
-(1) Spacing between second coils 13a to 13h (substantially,
This corresponds to the interval between the magnetic bodies 118 to 11h. ) is d, the difference equation 7idV(X) is AdV(x)−
(V (x+d)-V (x))/d
...(2). Therefore, AdV (x-d) −(V (x) −V (x-d
))/d・・・・・・(3).

Substituting the above equation (1) into equation (3) and rearranging, AdV
(X-d)-a ((2x+b/a)-d)...
・(4) becomes. By the way, the X coordinate value x1 that satisfies 7idV(X-d)-0 is x,--b/2a+ from the above equation (4).
d/2...(5). Since the coordinate value of the vertex of the function is X, θV (x, )/c
? x-2ax, +b-08°, x5=-b/2a
...-(6). Substituting the above equation (5) into equation (6) and rearranging it, we get X, xq-d/2
......(1). That is, Δd
By finding the X coordinate value X of the point where V(x-d) becomes O and subtracting d/2 from it, the coordinate X of the vertex of the function can be found.

Next, consider the coordinate value XQ. The coordinate value X, where AdV (X-d) becomes O, is the reference level ■ in Figure 6.
Between the differential voltage values v3 and ■4 before and after (coordinate values X and ×
4), so from equation (4) above, V3-a ((2x3+b/a)-d)...
(8) v -a ((2x4+b/a)-d)---
--(s), rearranging this, V a -V 4〽2a (x3-x4),', 2
a-(v3-V4)/(X3-X4)X 3-
Since X 4-d, 2 a --(v3- V4) /d --
-----(10). Here, since 2a indicates the slope in the difference curve, the height h in the Z direction is h
-A I 2 a l -----
--It is obtained from the formula (11). Note that A is a proportionality constant and is determined experimentally. FIG. 8 shows an example of the relationship between a and the height h of the input ben 20 in seven directions.
The change in a with respect to h is shown when a at -0(a) is set to 1.

Also, from the above equation (6) of the detection voltage, b/a-d--2x, ......(12
), so by substituting this into equations (8) and (9) above, V 3-2 a (X 3 X Q )
・・・・・・(13)v4-2a (x4-x,)
...(14). Furthermore, the corresponding (
13), dividing both sides of equations (14), we get v 3 / v 4 - (X 3 X a ) / (
×4−xq). Putting it as v3/v4-8 and rearranging it, x = (x3 Bx4)/ (I B)
・---(15) becomes. Since the loci 11x and x4 are known, Xq can be found from the ratio of ■3 and ■4, and furthermore, the above (
7) The coordinates X of the vertex can be found from the equation.

Further, a driving current source 3 is connected to the second coils 13a to 13h.
When the alternating current is switched from 0 one after another and passed, a magnetic flux is generated around it, and an induced voltage is generated in the first coil 12 due to electromagnetic induction due to this magnetic flux, but in this case as well, when the input pen 20 is placed The voltage generated in the first coil when an alternating current is applied to the second coil of the magnetic body closest to the position is the minimum value, and the voltage that increases as the distance from this magnetic body increases is the voltage at the second coil of the magnetic body. is generated in the first coil 12 when an alternating current is passed through the coil, and from these, the X coordinate value, Y coordinate value, and height h of the input bend 20 can be determined in the same manner as described above.

(Embodiment) 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. The magnetic materials 118 to 11h are materials that are difficult to magnetize 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 am. Magnetic materials 11a to 11h
are arranged in parallel with each other at a predetermined interval (approximately 511III). In addition, as an amorphous wire, for example, (Fe1-XCOX)75S11°B15 (atomic %)
(X indicates the ratio of Fe and Co, and takes a value of O to 1), etc. are used. The magnetic bodies 11a to 11h are cylindrical insulating members, such as the Envir tube 14a.
~14h, respectively. The first coil 12 and the second coils 13a to 13h are wound around the surfaces of the envire tubes 14a to 14h.

The first coils 12 are all wound in the same direction (left-handed in this embodiment), with the polarity of connection reversed between adjacent coils, and both ends thereof are connected to a drive current source 30. Further, the second coils 13a to 13h are also all wound in the same direction (left-handed in this embodiment), one end of each is connected to the position detection circuit 40, and the other end is commonly grounded. The position detection unit 10 consisting of these magnetic materials, Envira tube and coil is housed in a non-magnetic metal case 15.
It is fixed inside with adhesive etc. In addition, metal case 15
A lid 16 made of non-magnetic metal is placed over the top.

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 provides multiple (
It converts each of three 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. When the operation switch 26a is turned on, an infrared signal indicating a measurement start code is transmitted from the diode 25 to the reflector 24 and the transmission window 2.
3, and when the tip of the bar magnet 22 with the cover 29 attached is pressed against the input surface, the bar magnet 2
2 slides, switch 26b is turned on, and an infrared signal indicating a position input code signal is transmitted.

FIG. 13 shows a specific example of the drive current source 30. In the figure, 31 is an integrating circuit, 32 is a band pass filter, and 33 is a power driver. Integrating circuit 31 has its input terminal 3
4. Receives a clock pulse (or a pulse obtained by dividing the clock pulse) from the arithmetic processing circuit of the position detection circuit 40, which will be described later in 4.
This is integrated and converted into a triangular wave signal. The bandpass filter 32 converts the triangular wave signal into a sine wave signal. The power driver 33 is composed of an operational amplifier and a current amplifier, and current-amplifies the sine wave signal and sends it to the first coil 12 from its output terminal 35. In addition, the standard (
The reason why a clock pulse is used for the input signal is to synchronize with the position detection circuit 40.

FIG. 14 is a circuit block diagram showing a specific configuration of the position detection circuit 40, 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 pen 20 described above, the infrared signal is received by the infrared receiving diode 41, and is further amplified and waveform-shaped by the receiver 42, and is converted to the original signal. It is converted into a code signal, and further converted back into a measurement start command signal, and sent to the input buffer 43. The arithmetic processing circuit 44 is the input buffer 4
Read the command signal from 3 and press I! to start measurement. When this happens, a switching signal S1 is sent to the multiplexer 46 via the output buffer 45, and the induced voltages of the second coils 138 to 13h are sequentially input to the amplifier 47.

Each of the induced voltages is amplified by an amplifier 47, further rectified by a detector 48, and converted into a DC voltage detection signal S2,
It is further sent to the difference detection circuit 49 and converted into a difference detection signal S5 (however, this difference detection signal S5 is level-shifted so that it becomes a unipolar, here positive voltage signal due to the necessity of converting it to a digital value. ). Note that two sampling pulses 33 and 34 are inputted to the difference detection circuit 49 from the arithmetic control circuit 44 via an output buffer 745, as will be described later. The difference detection signal S5 is converted into a digital value by an analog-to-digital (A/D) converter 50 and sent to an arithmetic processing circuit 44 via an input buffer 43, but the arithmetic processing circuit 44 synchronizes with the switching signal. and read the digital value.

Furthermore, the arithmetic processing circuit 44 temporarily stores each of the differential voltage values (digital values) in the memory 51, and selects the reference level (1), the largest one among the smaller voltage values, and (2) the larger voltage value. The smallest positive value,
That is, the voltage values (2) and (2) before and after that are detected. Next, in the arithmetic processing circuit, a path 44 inputs vk+1 and its X coordinate value
, V4.

Assuming x and ×4, the calculation process of equation (15) is performed to obtain the coordinate value X, and the calculation process of equation (7) is further performed to obtain the coordinate value X. In addition, the height h is determined by calculating equation (11) as necessary.

The X coordinate value of the digital value obtained in this way
(or the coordinate value and its value is updated. Next, an infrared signal indicating a position input code is transmitted from the input pen 20, and when recognized by the arithmetic processing circuit 44 via the light receiving diode 41, receiver 42, and input buffer 43, the digital value at that point is The output buffer 5 receives the X coordinate value as the input value.
2 to a digital display (not shown) for display, or to a computer (not shown) for processing, or a digital-to-analog (D/A)
It is converted into an analog signal via a converter 53 and processed.

FIG. 16 shows the specific circuit number of the difference detection circuit 49. The detected signal S2 is sent to multiplexers 49b and 490 from the input terminal 49a. A reference level sampling pulse S3 is supplied to the multiplexer 49b from the arithmetic processing circuit 44, and during the high level period of the pulse, the voltage of the detection signal $2 is held in a sample hold circuit 496 consisting of a capacitor C1 and an operational amplifier OP1. . Similarly, the differential level sampling pulse S4 is supplied to the multiplexer 49c from the arithmetic processing circuit 44, and during the high level period of this pulse, the detected signal S4 is supplied to the multiplexer 49c.
2 voltage is held in a sample hold circuit 49e consisting of a capacitor C2 and an operational amplifier OP2. The voltages held in the sample and hold circuits 49d and 498 are input to the differential amplifier 49f, and a difference detection signal S5 corresponding to the difference is sent out from the output terminal 49g.

In the embodiments described above, signals indicating measurement start, position input, etc. were transmitted from the input pen 20 to the position detection circuit 40 using infrared signals, but ultrasonic signals may also be used. In addition, these signals simply inform the arithmetic processing circuit 44 of the timing of starting the operation of the position detection circuit 40 and inputting coordinate values! ! !
Since the information is for the purpose of making the user aware of the information, it is not particularly necessary to send it from the input pen 20, but it may be sent from a keyboard or other switch circuit provided in the position detection circuit 40 itself.

Furthermore, the height of the input pen 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 pen 20 is pressed against the input surface 100 of the position detection section 10, and the height h is set to a predetermined value, for example, 0 or 5a as described above.
When the value falls below a+, this is detected by the arithmetic processing circuit 44 and recognized as a position input signal.

FIG. 17 shows the input pen 60 used at this time.
At one end 62 of a pen shaft-shaped container 61 made of synthetic resin or the like,
A tapered bar magnet 63 is housed with the N pole facing toward the tip, and a cover 6 made of plastic or the like is roughly placed at the tip of the bar magnet 63.
4 is installed. Therefore, it is not necessary to provide the input pen 60 itself with an electric circuit or a battery as described above, and it is possible to input a position in connection with the operation of the input pen 60, 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. Furthermore, it has been confirmed through experiments that position detection can be performed with relatively high accuracy if the spacing between the magnetic bodies is approximately 2 to 6jII+.

Further, the position specifying magnetic generator is not limited to a permanent magnet, but may be an electromagnet.

FIG. 18 shows the configuration of a position detection circuit for successively extracting the induced voltages induced in the first coil 12 when alternating currents are switched and applied to each of the second coils 13a to 13h one after another. In the figure, 54 is a multiplexer;
5 is a driver, and the multiplexer 54 is switched and controlled by the switching signal S1, and applies the alternating current of the drive current source 30- to the second coils 138 to 13h of the position detection unit 10 via the driver 55. There is.

Further, the first coil 12 is connected to an amplifier 47 so as to send out an induced voltage. Drive current source 30'
is the drive current source 30 minus the power driver 33. Note that the other configurations and operations are similar to the position detection circuit shown in FIG. 14.

FIG. 19 shows another embodiment of the present invention. In the figure, reference numerals 70 and 80 indicate position detection units in the X direction and Y direction, each having the same configuration as the position detection unit 10 (however, the details are omitted for simplicity in the drawing). , the respective magnetic bodies are superimposed on each other so as to be orthogonal to the X direction and the Y direction, respectively. Also,
Reference numeral 90 designates a position detection circuit which is similar to the position detection circuit 40 except that it has two multiplexers for the X and Y directions, and performs position detection in the X and Y directions alternately. . Therefore, according to this embodiment, the position (coordinates) can be easily detected in two directions, the X direction and the Y direction, and in two more directions if necessary. In this case, position detection in two directions may be obtained from signals from either the X-direction position detection section 70 or the Y-direction position detection section 80. Note that the configuration of the input pen and the driving m* source 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 first and second coils are wound over the entire area around the magnetic body, the magnetic flux changes occur within the magnetic body, and the coupling is tight, making it possible to increase the detected voltage. The output change of the voltage can also be increased, and therefore the position detection range can be widened, and the signal-to-noise ratio is improved, making it less susceptible to external induction (and generating less external induction noise). In addition, since there is no need to exchange signals between the magnetic generator for position specification and other devices for position detection, it can be cordless, and furthermore, the magnetic bias required for position specification can be made cordless. Since the amount of magnetic flux is only a few oersteds (Oe), it is possible to specify the position even if the position specifying magnetic generator is separated from the position detecting section by some distance, and it is also possible to specify the position from the back side of the position detecting section. , metals other than ferromagnetic materials can also be placed on the input surface.

In addition, if the position detection section is provided in the X direction and the Y direction, position detection can be performed in two directions, the X direction and the Y direction, or in addition to the above, in the three directions of the Z) direction. There are advantages.

[Brief explanation of the drawing]

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 the magnetic flux applied to the magnetic body. Figure 4 is a diagram similar to Figure 3 seen from above the magnetic generator for position designation. Figure 5 is the induced voltage value generated in the second coil. A graph showing an example, Fig. 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 difference voltage value and the height of the magnetic generator for position specification. A graph showing an example of the relationship, FIG. 9 is a partially cutaway plan view showing a specific configuration of the position detection unit 10, FIG. A sectional view showing the specific configuration of the input pen,
FIG. 12 is an electric circuit diagram thereof, FIG. 13 is a circuit diagram showing the specific configuration of the drive current source, FIG. 14 is a circuit block diagram showing the specific configuration of the position detection circuit, and FIG. Figure 16 is a circuit diagram showing the specific configuration of the difference detection circuit, Figure 17 is a sectional view showing another embodiment of the input pen, and Figure 18 is the position detection circuit. FIG. 19 is an explanatory diagram showing another embodiment of the present invention. 10... Position detection unit, 20... Input pen, 30...
- Drive current source, 40...position detection circuit, 11a-11
h...Magnetic material, 12...First coil, 13a-1
3h...Second coil, 70...X-direction position detection section, 80...Y-direction position detection section. Patent Applicant Wacom Co., Ltd. Patent Attorney Furu 1) Takashi Seiji Figure 1 Figure 2 - 0,51,01,52,0 Oe Figure 3 @- Daken 7-day Figure 8 2 directions h f Figure 14 Figure 16-V 4PV S44 too. Figure 17 Figure 18

Claims (2)

[Claims] (1) A plurality of elongated magnetic bodies arranged substantially parallel to each other at predetermined intervals, and a first coil wound around each of the plurality of magnetic bodies over a wide range and connected in series. a position detection unit including a second coil wound over a wide range around each of the plurality of magnetic bodies and each independent of the second coil; and a position designation magnetic generator that generates a steady magnetic field. and the first coil or the second coil.
a drive current source that supplies an alternating current with a predetermined period to the first coil; and a drive current source that extracts an induced voltage induced in each of the second coils when the alternating current with the predetermined period is constantly applied to the first coil; When the alternating current of the predetermined period is switched and applied to each of the coils one after another, the induced voltages induced in the first coil are taken out one after another, and the difference between them is taken, and the difference voltage becomes equal to a predetermined reference voltage. The position is calculated, and from this the specified position on the position detection section by the position specification magnetic generator is calculated, and the slope of the differential voltage is calculated, and from this the specified position on the position detection section of the position specification magnetic generator is determined. A position detection device consisting of a position detection circuit for determining height. (2) A plurality of elongated X-direction magnetic bodies arranged substantially parallel to each other at predetermined intervals, and each of the plurality of X-direction magnetic bodies is wound over a wide range and connected in series. an X-direction position detection unit comprising: a X-direction coil, and a second X-direction coil that is wound over a wide range for each of the plurality of X-direction magnetic bodies and is independent of the X-direction second coil; , a Y-direction position detecting section having the same configuration as the X-direction position detecting section and superimposed thereon;
a position specifying magnetic generator that generates a steady magnetic field; a conversion circuit that supplies an alternating current with a predetermined period to the first coil in the X direction and the Y direction or the second coil in the X direction and the Y direction; When the alternating current of the predetermined period is constantly applied to the first coils in the X direction and the Y direction, extracting the induced voltage induced in each of the second coils in the X direction and the Y direction,
Alternatively, when the alternating current of the predetermined period is switched and applied to each of the second coils in the X direction and the Y direction, the induced voltages induced in the first coils in the X direction and Y direction are taken out one after another, and these The difference is taken, the position where the differential voltage is equal to a predetermined reference voltage is calculated, and from this the designated position on the position detection section in the X direction and Y direction by the position designating magnetic generator is determined, and Alternatively, a position detecting device comprising a position detecting circuit that calculates a slope of a differential voltage in the Y direction and determines the height of the position specifying magnetic generator with respect to the position detecting section in the X direction or the Y direction from this.