JPS6175420A - Position detecting device - Google Patents

Abstract

PURPOSE:To improve operability and to reduce the generation of an induced noise to the outside, and to perform high-precision position detection by providing a position detection part, driving current source, magnetic generator for position specification, and position detecting circuit. CONSTITUTION:The position detection part 10 is provided with excitation lines 12a-12n on one surface of a magnetic body 11 at specific intervals, and plural detection lines 13a-13n are provided on the other surface opposite. A driving current source 20 applies an alternating current having a specific period to the excitation lines, the magnetic generator 30 for position specification generates steady magnetism on a cordless basis, and the position detecting circuit 40 calculates the indication position of the generator 30. When the alternating current from the power source 20 flows to each excitation line, magnetic flux is established around it to induce an induced noise between two adjacent detection lines. In this case, the magnetic permeability of the magnetic body 11 is decreased by the generator 30, so the induced voltage rises, the SN ratio is improved, and induced noises to the outside are reduced to perform high- precision position detection and also improve the operability.

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; There were problems such as the need to hold the device and point it fairly close to each other. In addition, in the latter device, the position indicator can be made cordless, but the resolution of the coordinate position is determined by the line spacing, and if the line spacing is made small to increase the resolution, the SN ratio and stability will deteriorate. Therefore, it is difficult to increase the resolution, it is difficult to detect the position directly above the intersection of the drive line and the detection line, and the position indicator pen must be placed extremely close to the line, which increases the thickness of the input surface. There were problems such as not being able to place certain items and use them.

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.
3n, a position detection unit 1°, a drive current source 20,
It is equipped with a position designating magnetic generator 30 and a position detection circuit 40. Excitation 1m12a to 12n is magnetic body 1
The detection lines 138 to 1 are arranged parallel to each other at a predetermined interval (2 to 611110) on one surface 11a of 1.
3n is the excitation line 128 on the other surface 11b of the magnetic body 11
It is arranged at a position opposite to 12n. Adjacent lines of the excitation lines 12a to 12n are connected at different ends, that is, connected in series, and both ends thereof are connected to the drive current source 20. In addition, the detection lines 13a to 1
3n, all of their one ends are connected in common, and the other ends are respectively connected to the position detection circuit 40.

(Function) When an alternating current (such as a sine wave) is passed from the drive current source 20 to the excitation lines 128 to 12n, a magnetic flux (magnetic field) is generated around the excitation lines 128 to 12n, and this magnetic flux causes each of the detection lines 138 to 13 to
An induced voltage is generated between two adjacent wires of n.

Here, if the magnetic material 11 is permalloy or an amorphous alloy without magnetic anisotropy, the direction of the magnetic domains within the magnetic material 11 is irregular and can change greatly depending on the external magnetic field.
That is, since its magnetic permeability is large, as shown in FIG.
Since the direction of the nearby magnetic domains changes and the magnetic flux is mostly focused within the magnetic body 11, the induced voltage generated between the detection lines 13f and 13g becomes extremely small.

At this time, as shown in FIG. 2(b), the position specifying magnetic generator 30 is positioned above the area of the magnetic body 11, and a steady magnetic field (hereinafter referred to as magnetic bias) is applied from its tip.

), the direction of the magnetic domain in the magnetic body 11 is fixed in the direction of the magnetic field from the magnetic generator 30, that is, its magnetic permeability is reduced, so that the magnetic body follows the magnetic flux due to the alternating current of the excitation lines 12f and 12g. The direction of the magnetic domains within 11 does not change, the magnetic flux is not very focused within the magnetic body 11, and a relatively large induced voltage is generated between the detection lines 13f, 130.

In the case of permalloy or an amorphous alloy without magnetic anisotropy, the magnetic permeability decreases as the magnetic bias increases, as shown in FIG.
As shown in FIG. 4, between the two adjacent detection lines 13n, the voltage between the two detection lines closest to the position where the position specifying magnetic generator 30 is placed is taken as the maximum value, and then the voltage is moved away from this point. Accordingly, a voltage v-v13 is generated that gradually decreases.

In FIG. 4, the horizontal axis indicates the coordinate position in the direction (hereinafter referred to as the X direction) orthogonal to the detection lines 138 to 13rl,
The vertical axis shows the voltage value. Here, the coordinate value X −X
indicates the position where each voltage V-v13 is generated (assuming that the voltage is generated at an intermediate position between two adjacent detection lines).

By extracting each voltage v - v13 with the position detection circuit 40 and calculating the X coordinate value at which the induced voltage becomes the maximum value from this, the X coordinate value X of the position specifying magnetic generator 30 can be determined. .

One calculation method for determining the coordinate value X is to approximate the waveform near the maximum value in FIG. 4 by an appropriate function, and then determine the coordinates of the maximum value of the function. For example, each coordinate
""X13 interval (substantially, each detection line 13a to 13
This corresponds to an interval of n. ) is ΔX, and by approximating coordinates from coordinate x5 to coordinate First, from the voltage and coordinate values of each detection line, V5=a (x,, -xS) +b -・-・-
(1)v=a(x6-x8)+b...
(2) V7=a (x, -x,) +b ・-・
-(3J. Here, a and b are constants (a<O).

Also, X6 Xs””ΔX ・−・・−(
4) x 7 x 5 = 2ΔX...
...(5). Expressions (4) and (5) are replaced by (2) and (3)
) into the formula and square it, we get X −×5+ΔX/2 ((3V5−4V6+v,)/
(V5-2V6+V7))...(6) It becomes. Therefore, between the detection lines 138 and 13f, 13f and 1
Lumi pressure v induced between 3g, 13G, and 13i, respectively
, V6. The X coordinate value of the position specifying magnetic generator 30 can be calculated by calculating the equation (6) in the position detection circuit 40 from V7 and the coordinate value x5 (known). Furthermore, the same X coordinate value can be obtained even if the magnetic generator 30 is moved along the excitation line or the detection line.

On the other hand, when the magnetic body 11 is an amorphous alloy with magnetic anisotropy and the direction of the magnetic anisotropy in the magnetic body 11 is made to match the direction perpendicular to the excitation line and the detection line,
Since the directions of the magnetic domains are all aligned, that is, the magnetic permeability has a certain degree of magnitude, as shown in Fig. 5(a), 2
The direction of the magnetic domain in the magnetic body 11 does not change much due to the magnetic flux caused by the alternating current of the book's excitation lines, for example 12f and 12, and the magnetic flux is only focused to a certain extent within the magnetic body 11. A relatively large induced voltage is generated between the detection lines 13f and 13(1).

At this time, as shown in FIG. 5(b), when the position specifying magnetic generator 30 is positioned above the area of the magnetic body 11 and a magnetic bias of a certain strength is applied, the magnetic domain within the magnetic body 11 is The direction of the excitation line 12f becomes irregular and can be changed greatly by an external magnetic field, that is, the magnetic permeability increases.

The direction of the magnetic domain within the magnetic body 11 changes according to the magnetic flux caused by the 12G alternating current, and most of the magnetic flux is focused within the magnetic body 11, so the induced voltage generated between the detection lines 13f and 130 becomes extremely small. .

As shown in FIG. 6, the magnetic permeability is maximized when a magnetic bias of a certain strength is applied, so there is a position between two adjacent detection lines 138 to 13n as shown in FIG. The voltage between the two detection lines closest to the position where the designated magnetic generator 30 is placed is taken as a minimum value, and voltages v1- to v13' are generated that gradually increase as the distance from this value increases. Therefore, similarly to the above, in the position detection circuit 40, each voltage v1-
~v13' and calculate the X coordinate value at which the induced voltage becomes the minimum value, then the position designating magnetic generator 3
The X coordinate value X of 0 can be found.

As mentioned above, the excitation lines 12a to 12n and the detection line 13
a to 13n are surfaces 11a and 11b of the magnetic body 11, respectively.
Since it is only necessary to provide the magnetic body 11 in the magnetic body 11 and there is no need to wind it around the magnetic body 11, the structure of the position detection unit 10 is simplified and its manufacture becomes easy. In addition, since there is no need to exchange signals between the position specifying magnetic generator 30 and other devices for position detection, it can be cordless, and the magnetic bias required for position specification can be reduced. As shown in FIGS. 3 and 6, the width of the opening is only a few oersteds (Oe), so that the position specifying magnetic generator 30 can specify the position even if it is separated from the position detecting section 10 by some distance.

(Example) FIG. 8 shows a specific example of a drive current of 8!20.

In the figure, 21 is a function generator, for example, an IC1803g manufactured by Intersil, which outputs a sine wave signal of a predetermined frequency determined by the values of a capacitor C and a resistor R. Further, 22 is a power driver, which is composed of an operational amplifier and a current amplifier, and amplifies the current of the sine wave signal and sends it to the excitation lines 12a to 12n.

FIG. 9 is a sectional view showing a specific example of the position specifying magnetic generator 30, and FIG. 10 is an electric circuit diagram thereof.

In the figure, numeral 31 is a pen-shaped container made of synthetic resin or the like, and a magnetism generator 32, which will be described later, is housed in one end of the pen-shaped container so as to be slidable in the axial direction. Moreover, 33 is an operation switch, which is attached opposite to the other end of the magnetic generator 32. Further, 34 is an ultrasonic signal transmitter, and 35 is an ultrasonic wave transmitter, which are housed at appropriate locations in the container 31 together with a battery 36.

When the container 31 is held and the tip of the magnetic generator 32 is pressed against the input surface, the magnetic generator 32 slides and the switch 33 is turned on, thereby operating the oscillation circuit 34a and amplifier 34b in the transmitter Ia34. , the transmitter 35 converts a signal 2 indicating coordinate input, such as a continuous pulse signal of a predetermined frequency, into an ultrasonic signal and transmits it.

FIG. 11 shows details of the magnetic generator 32, 32a
A bar magnet 321) is a bottomed cylindrical yoke, and the bar magnet 32a is disposed at a predetermined interval approximately on the inside of the yoke 32b. This configuration was created by
This is because higher output can be obtained if the magnetic flux is directed horizontally. Note that a bar magnet having an extremely short length in the magnetic pole direction may be used as the magnetic generator.

FIG. 12 is a circuit block diagram showing a specific configuration of the position detection circuit 40. In the same figure, when an ultrasonic signal indicating a coordinate input is sent out from the above-mentioned transmitter 35, the ultrasonic signal is received by a receiver 41, and further amplified by a receiver 42.
The waveform is shaped and sent to the input buffer 743. The arithmetic processing circuit 44 reads the coordinate input signal from the input buffer 43, and when it recognizes the start of measurement, sends a control signal to the multiplexer 46 via the output buffer 45, and sends a control signal between two adjacent detection lines 13a to 13n. The induced voltages are sequentially input to the amplifier 47. Each of the induced voltages is amplified by an amplifier 47, rectified by a detector 48, and converted into a DC voltage, further converted into a digital value by an analog-to-digital (A/D) converter 49, and processed through an input buffer 43. The signal is sent to circuit 44. The arithmetic processing circuit 44 temporarily stores each induced voltage (digital value) in the memory 50, and detects a voltage value near the maximum value (or minimum value) from among these. For example, when the magnetic material 11 is made of permalloy or an amorphous alloy without magnetic anisotropy, the magnitude of each induced voltage is sequentially compared, and if a certain voltage, V, is the previous voltage vk-1. The larger and next voltage vk.

When it is larger than (V k-1< V h > V k+
1) The iC1 voltage vk can be detected as a maximum value voltage. The arithmetic processing circuit 44 receives the voltage vk-1''
k.

v, +1 and convert them into voltages v5. v6. As v7, the arithmetic processing of equation (6) is performed to obtain coordinate values.

The coordinate values of the digital values obtained in this way are sent via the output buffer 51 to a digital display (not shown) for display, or sent to a computer (not shown) for processing, or are sent to a digital display (not shown) for processing. The signal is converted into an analog signal via an analog (D/A) converter 52 and processed.

Note that the numbers of excitation lines and detection lines in the examples are merely examples, and it goes without saying that the numbers are not limited thereto. Further, the position specifying magnetic generator is not limited to a permanent magnet, but may be an electromagnet.

Further, in the embodiment described above, the signal indicating coordinate input was transmitted from the position specifying ceramic generator 30 to the position detection circuit 40 using an ultrasonic signal, but an optical signal such as infrared rays may also be used. Further, since the signal indicating the coordinate input is simply for making the arithmetic processing circuit 44 recognize the timing of the input of the coordinate value, it is not particularly necessary to send it from the magnetic generator 30, but to the position detection circuit 40 itself. A signal for recognizing the timing may be sent from a keyboard or other switch circuit provided. In addition, the position detection circuit 40
Alternatively, the coordinates may be detected at all times, and the coordinates at that time may be input when the signal is received.

FIG. 13 shows another embodiment of the invention. In the same figure, reference numerals 60 and 70 indicate position detection units in the X direction and Y direction, which have the same configuration as the position detection unit 1o, and whose respective excitation lines and detection lines are arranged in the X direction and the Y direction, respectively. 80 is a position detection circuit, which has two multiplexers for the X direction and Y direction, so that position detection in the X direction and Y direction can be performed alternately. The circuit is the same as the position detection circuit 40 except for the above.Therefore, according to this embodiment,
Positions (coordinates) in two directions, the direction and the Y direction, can be easily detected. Note that the configurations of the drive current source and the magnetic generator for position designation may be the same as in the previous embodiment.

(Effects of the Invention) As explained above, according to the present invention, excitation lines are provided at predetermined intervals on one surface of a flat magnetic body, and at positions opposite to the excitation lines on the other surface. a position detection unit including a plurality of detection lines; a drive current source that applies an alternating current at a predetermined period to the excitation line; a position designating magnetic generator that generates a steady magnetic field; and a position detection unit adjacent to each detection line. The present invention is equipped with a position detection circuit that extracts the induced voltages induced between the two wires and calculates the indicated position of the position specifying magnetic generator from these, so that the magnetic flux change between the excitation wire and the detection wire is It takes place inside the body, and the tighter the bonds, the higher the detection voltage.
Therefore, the S/N ratio is improved, and it is less susceptible to external induction (and generates less external induction noise. In addition, the excitation line and the detection line only need to be provided on each side of the magnetic body, and the magnetic body Since there is no need to wind it around the magnetic material, the structure of the position detection part becomes simple and its manufacture becomes easy.Furthermore, since the position can be specified by applying a slight magnetic bias to the magnetic material, the magnetic material for position specification can be used. There is no need to place the generator close to a magnetic material, the effective reading height can be increased, and metals other than ferromagnetic materials can be placed on the input surface.Furthermore, it is possible to use signals such as timing detection. The magnetic generator for position designation can be made cordless without the need for a cordless magnetic generator, which has good operability.In addition, if the position detection part is provided in the X direction and the Y direction,
This has the advantage that directional position detection is possible.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIGS. 2(a) and 2(b) show a magnetic material made of permalloy or an amorphous alloy without magnetic anisotropy. Figure 3 shows the magnetic flux of the excitation line when using
The figure is a characteristic diagram of magnetic bias versus magnetic permeability of a magnetic material made of permalloy or an amorphous alloy without magnetic anisotropy.
The figure is a graph showing an example of the induced voltage generated between two adjacent detection lines when a magnetic material made of permalloy or an amorphous alloy without magnetic anisotropy is used.
) (b) is the same diagram as Fig. 2 (a) and (b) when using a magnetic material made of an amorphous alloy with magnetic anisotropy, and Fig. 6 shows a magnetic material made of an amorphous alloy with magnetic anisotropy. Figure 7 is a diagram similar to Figure 4 when a magnetic material made of an amorphous alloy with magnetic anisotropy is used. Figure 8 shows a specific example of the drive current source. Electric circuit diagram, FIG. 9 is a V sectional view showing a specific example of a magnetic generator for position designation, FIG. 10 is an electric circuit diagram thereof, FIG. 11 is a sectional view showing a specific example of a magnetic generator, and FIG. 12 13 is a circuit block diagram showing a specific configuration of a position detection circuit, and FIG. 13 is an explanatory diagram showing another embodiment of the present invention. 10... Position detection unit, 20... Drive current source, 30
...Magnetic generator for position specification, 40...Position detection circuit, 11...Magnetic material, 12a-12n...Excitation! ! line,
13a to 13n... detection line, 60... X direction position detection section, 70... Y direction position detection section. Patent Applicant Wacom Co., Ltd. Patent Attorney Yoshi 1) Takashi Figure 2, 6) (.) Figure 5 (b) Figure 3 Figure 6 Figure 1 Illusion i% Ias Figure 4' / l Jt Sum × 5 Figure 7 Book = X5 Seed 8. A1 Figure 8 Figure 9 Figure 12

Claims (2)

[Claims] (1) a position detection unit comprising excitation lines provided at predetermined intervals on one surface of a flat magnetic body, and a plurality of detection lines provided on the other surface at positions facing the excitation lines; A drive current source that applies an alternating current with a predetermined period to the excitation line, a position specifying magnetic generator that generates a steady magnetic field, and extracts the induced voltage induced between two adjacent detection lines. A position detecting device comprising: a position detecting circuit that calculates the indicated position of the position specifying magnetic generator from these. (2) An X-direction position detection unit comprising excitation lines provided at predetermined intervals on one surface of a flat magnetic body, and a plurality of detection lines provided on the other surface at positions facing the excitation lines. , a Y-direction position detecting section having the same configuration as the X-direction position detecting section and superimposed thereon, and a driving current source that applies an alternating current at a predetermined period to the excitation lines in the X-direction and the Y-direction. , a magnetic generator for position designation that generates a steady magnetic field, and the induced voltages induced between two adjacent detection lines in the X direction and the Y direction, respectively, are taken out from the magnetic generator for position designation. 1. A position detection device comprising: a position detection circuit that calculates the indicated position in the X direction and the Y direction.