JPS626251B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention detects a position 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.

(Prior Art and Problems) Conventional position detection devices generate magnetostrictive vibration waves in the magnetostrictive transmission medium by applying a pulse current to a drive coil provided at one end of the magnetostrictive transmission medium or at the tip of a position indicating pen. From that point on, a processor or the like measures the time until an induced voltage based on the magnetostrictive oscillation waves is detected in a detection coil provided at the tip of the positioning pen or at one end of the magnetostrictive transmission medium, and from this time the indicated position of the positioning pen is determined. There was something that I did to calculate. Although this device has relatively good position detection accuracy, it requires a cord between the pen and the device in order to send and receive timing signals, etc. between the pen and the processor, which severely limits its handling. ,
It is susceptible to guidance from other devices, causing malfunctions,
On the other hand, there is a possibility that the pen may become a source of noise, and there are also other problems such as the need to hold the pen perpendicularly to the magnetostrictive transmission medium and to point it fairly close to it.

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. With this device, the positioning pen can be made cordless, but the resolution of the coordinate position is determined by the line spacing, and if you reduce the line spacing to increase the resolution, the signal-to-noise ratio and stability will deteriorate, and therefore the resolution will decrease. In addition, 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, making it difficult to place thick objects on the input surface. There were some problems, such as not being able to use it by leaving it in place.

(Object of the Invention) The present invention improves these conventional drawbacks, and the magnetic generator for position designation is not connected anywhere, has good operability, is resistant to external guidance, and emits noise. Our goal is to provide a highly accurate position detection device that never fails.

(Embodiment of the Invention) FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the invention. In the figure, 10 is an X-direction position detection section, 20 is a Y-direction position detection section, 30 is a drive current source, 41 and 42 are signal selection means, such as a multiplexer, and 50 is a position specifying magnetic generator, such as a bar magnet. 60 is a processing device.

The X-direction position detection unit 10 includes a long magnetic body 11a~
11e, excitation lines 12a to 12i, and detection lines 13a to
13h and insulating sheets 14 and 15. Each magnetic body 11a to 11e has an insulating sheet 14,
15 are attached parallel to each other so that the longitudinal direction thereof runs along the X direction. Also, the magnetic body 11a~
The material 11e is preferably a material that is difficult to be magnetized even when a magnet is brought close to it, that is, has a small coercive force and has a high magnetic permeability (μ), such as an amorphous alloy or a permalloy alloy. As an amorphous alloy, for example, Fc ₇₉ B ₁₆ Si ₅ (atomic %) (coercive force 0.2 Oe, magnetic permeability μ
= 14000) etc. can be used. In addition, the magnetic material 11
A to 11e have an elongated shape, and the cross section is preferably a rectangular thin strip or a circular linear shape, and in the case of a thin strip, it is about several mm, and the thickness is about several μm to several tens of μm, which is easy to manufacture. The characteristics are also good. Amorphous amorphous alloys can be manufactured into thin pieces with a thickness of 20 to 50 μm, so they can be cut into thin strips, and linear ones with circular cross sections can also be made, so they can be used as is. .

Each of the excitation wires 12a to 12i is a portion disposed on the upper surface of the insulating sheet 14 (hereinafter referred to as an upper half portion).
and a portion disposed on the lower surface of the insulating sheet 15 (hereinafter referred to as the lower half) are continuous at one end thereof, and excitation wires 12a to 12b,
12c, 12d, 12e, 12f, 12g, 12
the other end of the lower half of h and the excitation lines 12b, 12c, 1
2d, 12e, 12f, 12g, 12h, 12i
The other ends of the upper half are connected to each other, that is, the excitation wires 12a to 12i are connected in series, and the excitation wires 12a to 12i are connected in series.
The other end of the upper half of the excitation line 12i and the other end of the lower half of the excitation line 12i are connected to a drive current source 30. Also, each excitation line 1
2a to 12i are arranged parallel to each other at predetermined intervals so as to be orthogonal to the longitudinal direction of the magnetic bodies 11a to 11e.

Each of the detection lines 13a to 13h is located on the upper surface of the insulating sheet 14 (hereinafter referred to as the upper half).
and a portion disposed on the lower surface of the insulating sheet 15 (hereinafter referred to as the lower half) are continuous at one end, and the other ends of the upper half of the detection lines 13a to 13h are connected to the multiplexer 41, respectively. connected to,
The other ends of the lower halves of the detection lines 13a to 13h are commonly grounded. The detection lines 13a to 13h are arranged parallel to each other between the excitation lines 12a to 12i, and perpendicular to the longitudinal direction of the magnetic bodies 11a to 11e.

The Y-direction position detection section 20 includes a long magnetic body 21a~
21e, excitation lines 22a to 22i, and detection lines 23a to
23h and insulating sheets 24 and 25, and its detailed structure is the same as that of the X-direction position detection section 10. The Y-direction position detection section 20 is superimposed on the lower part of the X-direction position detection section 10 via an insulating sheet (not shown), etc., as close as possible so that the magnetic body, excitation line, and detection line are perpendicular to each other (however, as shown in the drawings, (In order to make the structure easier to understand, the X-direction position detection section 10 and the Y-direction position detection section 20 are drawn separately.) In addition, each excitation line 22a to 22i
are connected to the drive current source 30, and each detection line 23a~
23h is connected to multiplexer 42.

The drive current source 30 constantly supplies an alternating current with a predetermined period (the alternating current here includes all of sine waves, rectangular waves, triangular waves, etc.) to the excitation lines 12a to 12i and 2.
2a to 22i. Further, the multiplexers 41 and 42 are configured to selectively send the output signals of the detection lines 13a to 13h and 23a to 23h to the processing device 60 in accordance with a control signal from the processing device 60.

Further, 43 is a processing device 60 that sends instructions to start measurement, etc.
a transmitter that transmits an ultrasonic signal to notify the
Reference numeral 4 denotes a receiver for receiving this ultrasonic signal, and in this embodiment, an ultrasonic ceramic microphone for both transmitting and receiving purposes is used for both. Note that an example of how the wave transmitter 43 and wave receiver 44 are used will be described in detail later.

In such a configuration, the detection lines 13a to 13
h and 23a to 23h are the excitation lines 12a to 1
An induced voltage is generated by electromagnetic induction based on the alternating current flowing through 2i and 22a to 22i. This electromagnetic induction
Since the magnetic materials 11a to 11e
The larger the magnetic permeability of 21a to 21e, the larger the voltage value of the induced voltage becomes. By the way, the magnetic permeability of the magnetic bodies 11a to 11e and 21a to 21e is as follows:
It changes as shown in FIG. 2 by a magnetic bias applied from the outside, and as the magnetic bias becomes stronger, the magnetic permeability decreases rapidly. Therefore, the magnetic material 11
When a magnetic bias is applied to a to 11e and 21a to 21e, the excitation lines 12a to 12i, 22a to 22
The voltage induced from i to the detection lines 13a to 13h, 23a to 23h also becomes smaller.

Now, in FIG. 1, the position specifying bar magnet 50 is placed at a distance x in the X direction from the detection line 13a with its N pole facing down.
It is located on the position A of the X-direction position detection unit 10, which is separated from the detection line 23a by the distance y _S in the _Y direction, and applies a magnetic bias to the extent that the magnetic permeability is reduced to the magnetic body 11.
b and 12d.

At this time, induced voltages _V1 to _V8 as shown in FIG. 3 are generated in the detection lines 13a to 13h in the X direction.
In FIG. 3, the horizontal axis indicates coordinate positions in the X direction, where the positions of the detection lines 13a to 13h are x ₁ to x ₈ , respectively, and the vertical axis indicates voltage values.
V ₁ to V ₈ once decrease on both sides of position A, then increase again, and become almost equal to the original voltage just below position A. This is because the magnetic flux incident on the magnetic body 11b from the bar magnet 50 is almost orthogonal to the magnetic body 11b directly below the bar magnet 50, so the influence on magnetic permeability is small, and on both sides, the magnetic flux passing in the longitudinal direction of the magnetic body 11b. This is because the magnetic permeability decreases. Since each of the voltages V ₁ to V ₈ is obtained from the multiplexer 41, if the X-coordinate value at which the induced voltage once decreases and then reaches a peak is calculated by the processor 60, the X-coordinate value of the bar magnet 50 is obtained. You can know X _S.

One calculation method for determining the coordinate value x _S is to approximate the waveform near the peak point in FIG. 3 by an appropriate function, and then determine the coordinates of the peak point of the function. For example, if the interval between each detection line 13a to 13h is Δx and the coordinates x ₃ to x ₅ in FIG. 3 are approximated by a quadratic function (indicated by a solid line in the figure), the calculation can be performed as follows. I can do it. First, from the voltage and coordinate values of each detection line, V ₃ = a (x ₃ - x _S ) ² + b ... (1) V ₄ = a (x ₄ - x _S ) ² + b ... (2) V ₅ = a( _x5 - _xs ) ² +b...(3). Here, a and b are constants (a<0). Also, x ₄ −x ₃ =Δx ……(4) x ₅ −x ₃ =2Δx ……(5). Substituting equations (4) and (5) into equations (2) and (3) and rearranging, x _S = x ₃ + Δx/2 (3V ₃ -4V ₄ +V ₅ /V ₃ -
2V ₄ +V ₅ )...(6). Therefore, the detection lines 13c, 13d, 13e
The X coordinate value of the position designating bar magnet 50 can be calculated by sending the voltages V ₃ , V 4 , and V 5 induced by the voltages V 3 , V ₄ , and V ₅ to the processing device 60 and calculating the equation (6). Further, even if the bar magnet 50 is moved along the Y axis, the same X coordinate value can be obtained.

Also, a third
An induced voltage similar to that shown in the figure is obtained, and the Y coordinate value y _S can be determined by the same calculation process as described above.

The magnetic field emitted from the tip of the position specifying bar magnet 50 is approximated to be emitted from a point r on the extension of the center line of the bar magnet 50, as shown in FIG. Therefore, the input surface 1 is located at a position corresponding to the distance from the magnetic bodies 11a to 11e and 21a to 21e to the point r.
00, the bar magnet 50 becomes the magnetic body 11a~
11e and 21a to 21e (however, the illustrated example shows that the bar magnet 50 is in a tilted state with reference to the magnetic body 11a indicated by the two-dot chain line). The direction of the magnetic field does not change and its detection position also does not change, so the position can be specified without being affected by the inclination of the bar magnet 50. In addition, in experiments, the slope was within ±30°,
Achieved error of ±0.5mm or less (height of input surface
12mm).

FIG. 5 shows a specific example of the drive current source 30. In the figure, numeral 31 is a function generator, for example, Intersil IC 8038, which outputs a sine wave signal of a predetermined frequency determined up to the values of capacitor C and resistor R. Further, 32 is a power driver, which is composed of an operational amplifier and a differential amplifier, and current-amplifies the sine wave signal and sends it to the excitation lines 12a to 12i and 22a to 22i.

FIG. 6 is a sectional view showing a specific example of the position designating magnetic generator 50, and FIG. 7 is an electric circuit diagram thereof. In the figure, 51 is a pen-shaped container made of synthetic resin, etc., and a bar magnet 5 with a tapered tip is attached to one end of the pen-shaped container.
2 is accommodated so as to be slidable in the axial direction. Also,
Reference numeral 53 denotes an operation switch, which is attached opposite to the other end of the bar magnet 52. Further, 54 is a transmitter for ultrasonic signals, and 55 is a battery, which is housed in a proper place in the container 51 together with the wave transmitter 43. Said container 5
A bar magnet 5 that holds 1 and has a rubber cover 56 attached.
When the tip of the bar magnet 52 is pressed against the input surface, the bar magnet 52
slides to turn on the switch 53, which causes the oscillation circuit 54a in the transmitter 54 and the amplifier 5 to turn on.
4b is activated, and the transmitter 43 converts a signal indicating the start of measurement, for example, a continuous pulse signal of a predetermined frequency, into an ultrasonic signal and transmits it.

FIG. 8 is a circuit block diagram showing a specific configuration of the processing device 60. In the figure, when an ultrasonic signal indicating the start of measurement is sent out from the above-mentioned transmitter 43, the ultrasonic signal is received by a receiver 44, further amplified and waveform-shaped by a receiver 61, and then signal,
For example, it is returned to a continuous pulse signal with a predetermined period and sent to the input buffer 62. When the arithmetic processing unit 63 reads the continuous pulse signal from the input buffer 62 and recognizes the start of measurement, it sends a control signal to the switching circuit 65 and the multiplexer 41 via the output buffer 64 to adjust the induced voltage of the detection lines 13a to 13h in the X direction. are sequentially input to the amplifier 66. Each of the induced voltages is amplified by an amplifier 66, rectified by a detector 67 and converted into a DC voltage, further converted into a digital value by an analog-digital (A/D) converter 68, and processed through an input buffer 62. It is sent to device 63. The arithmetic processing unit 63 temporarily stores each of the induced voltages (digital values) in a memory 69, and detects a voltage value near the peak from among them. As this detection method, for example, the magnitude of each induced voltage is compared sequentially, and if a certain voltage, _Vk , is larger than the previous voltage Vk _-1 and larger than the next voltage Vk ₊₁ , then _{Vk- 1} <V _k >V _k+1 ), the voltage V _k can be detected as a peak voltage. The arithmetic processing unit 63 takes out the voltages V _k-1 , V _k , V _k+1 and converts them into voltages in the equation (6), respectively.
Perform the arithmetic processing of equation (6) as V ₃ , V ₄ , and V ₅ , and
Find the coordinate values.

Next, the arithmetic processing unit 63 sends a control signal to the switching circuit 65 and the multiplexer 42 via the output buffer 64, sequentially inputs the induced voltages of the detection lines 23a to 23h in the Y direction, performs the same processing as described above, and Find the value. The X and Y coordinate values of the digital values obtained in this way are output to the output buffer 70.
is sent to a digital display (not shown) for display, or sent to a computer (not shown) for processing, or converted to an analog signal via a digital-to-analog (D/A) converter 71. and processed.

FIG. 9 is a perspective view showing another embodiment of the present invention, in which only the X-direction position detection section is shown. In the figure, 80 is an X-direction position detection unit, which includes long magnetic bodies 81a to 81f and excitation lines 82a to 82j.
and detection lines 83a to 83g. The magnetic bodies 81a to 81f are arranged parallel to each other so that their longitudinal directions extend along the X direction. Note that the materials of the magnetic bodies 81a to 81f are the same as in the previous embodiment. Each excitation line 82a to 82j is a magnetic body 8
Excitation lines 1a to 81f are arranged parallel to each other at predetermined intervals so as to be perpendicular to their longitudinal directions, but between excitation lines 82a and 82b and between 82i and 82j.
The interval between them is set smaller than the other intervals.
Moreover, each excitation line 82a to 82j is connected to each magnetic body 81a.
Each part corresponding to 81f is arranged in the opposite direction for each adjacent part, and furthermore, the magnetic body 81
The portions corresponding to a and 81f are smaller than the other portions, that is, they are attached closer to the magnetic body. The excitation lines 82a to 82j are connected in series so that the same magnetic flux is generated in each of the magnetic bodies 81a to 81f when current is applied, and both ends of the excitation lines 82a to 82j are connected to the drive current source 30.

Each detection line 83a to 83g is an excitation line 82.
They are arranged around the magnetic bodies 81a to 81f so as to be parallel to each other and perpendicular to the longitudinal direction of the magnetic bodies 81a to 81f between the magnetic bodies 81a to 82i. In addition, each detection line 83a to 83g corresponds to each magnetic body 8.
Each part corresponding to 1a to 81f is arranged in the opposite direction for each adjacent part, and furthermore, the magnetic body 8
The portions corresponding to 1a and 81f are smaller than the other portions, ie, are attached closer to the magnetic body. Further, one end of each of the detection lines 83a to 83g is connected to the multiplexer 41, and the other end is commonly grounded.

According to the above configuration, when a driving current is applied to the excitation lines 82a to 82j, the magnetic fluxes generated in each of the parts are in opposite directions for each magnetic body, so that they cancel each other out and the induction and noise emitted to the outside are weakened. In addition, when magnetic flux is applied in one direction to the detection lines 83a to 83g, the currents generated from each part are in opposite directions, so external induction and noise cancel each other out and are weakened, resulting in an induced voltage with a good S/N ratio. can be taken out. In addition, magnetic bodies 81a to 81f
Since the number of excitation lines is greater in the portions corresponding to both ends in the longitudinal direction than in other portions, the detected voltage does not drop. In addition, because the excitation lines and detection lines for the magnetic bodies at both ends of the plurality of magnetic bodies arranged in parallel, that is, 81a and 81f, are arranged closer to each other than the other magnetic bodies, the electromagnetic coupling becomes dense, and in this part The detection voltage also does not drop.

In this example, the excitation line and the detection line are provided so that the directions of magnetic flux and current are opposite to each other for each magnetic body, but the excitation line and the detection line are provided so that the directions of magnetic flux and current are opposite to each other for two or more adjacent magnetic bodies. You can also do it.

Note that the numbers of magnetic bodies, excitation lines, and detection lines in the examples are merely examples, and it goes without saying that the numbers are not limited thereto. Furthermore, it has been confirmed through experiments that position detection can be performed with relatively high accuracy if the distance between the detection lines is approximately 2 to 6 mm. In addition, the magnetic generator for position specification is not limited to bar magnets,
It may be a plate, ring, square body, etc., or it may be an electromagnet.

(Effects of the Invention) As explained above, according to the present invention, excitation lines and detection lines are alternately arranged in parallel to a plurality of long magnetic bodies arranged substantially parallel to each other so as to be perpendicular to their longitudinal directions. a Y-direction position detecting section having a similar structure to the X-direction position detecting section and overlaid thereon;
a drive current source that applies an alternating current with a predetermined period to each excitation line in the X direction, a position specifying magnetic generator that applies a local magnetic bias to each magnetic body in the X direction and Y direction, and The indicated coordinates of the position specifying magnetic generator are calculated from X-direction and Y-direction signal selection means connected to each detection line, respectively, and each induced voltage taken out from the X-direction and Y-direction signal selection means. Since it is equipped with a processing device, the magnetic flux change between the excitation line and the detection line occurs only within the magnetic body, and the coupling is tight, the detection voltage is large, the signal-to-noise ratio is good, and it is not susceptible to external induction. In addition, less induced noise is generated to the outside. In addition, since the position can be specified by simply applying a slight magnetic bias to the magnetic material, there is no need to bring the positioning magnetic generator close to the magnetic material, and the effective reading height can be increased. It can also be sandwiched between other metals. Furthermore, the magnetic generator for position designation can be made cordless without requiring signals such as timing detection, and there are advantages such as good operability.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the present invention, FIG. 2 is a characteristic diagram of magnetic bias versus magnetic permeability, and FIG. 3 is a diagram showing characteristics of magnetic bias in the X direction. A graph showing an example of the induced voltage generated in each detection line, Fig. 4 is an explanatory diagram showing the magnetic flux applied to the magnetic material from the position specifying bar magnet, and Fig. 5 shows a specific example of the drive current source. Electric circuit diagram, FIG. 6 is a sectional view showing a specific example of a magnetic generator for position designation,
FIG. 7 is an electric circuit diagram thereof, FIG. 8 is a circuit block diagram showing a specific configuration of the processing device, and FIG. 9 is a perspective view of an X-direction position detecting section in another embodiment of the present invention. 10...X-direction position detection section, 20...Y-direction position detection section, 30... Drive current source, 41, 42...
Multiplexer, 50... Magnetic generator for position specification, 60... Processing device, 11a to 11e, 21a
~21e...Magnetic material, 12a~12i, 22a~
22i...excitation line, 13a-13h, 23a-2
3h...detection line.

Claims (1)

[Scope of Claims] 1. An X-direction position detection unit comprising a plurality of elongated magnetic bodies arranged substantially parallel to each other, and excitation lines and detection lines arranged side by side alternately so as to be orthogonal to their longitudinal directions. , a Y-direction position detecting section having the same structure as the X-direction position detecting section and superimposed thereon, and a driving current source applying an alternating current with a predetermined period to each of the excitation lines in the X-direction and the Y-direction; a position specifying magnetic generator that applies a local magnetic bias to each of the magnetic bodies in the X direction and the Y direction; and signal selection means in the X direction and Y direction connected to each of the detection lines in the X direction and Y direction, respectively. and a processing device that calculates indicated coordinates of the position specifying magnetic generator from each induced voltage taken out from the signal selection means in the X direction and the Y direction. 2. So that the direction of the magnetic flux generated by the excitation lines in the X and Y directions or the direction of the current generated in the excitation lines in the X and Y directions is opposite for each magnetic body or for each two or more adjacent magnetic bodies. 2. The position detection device according to claim 1, further comprising excitation lines in the X direction and the Y direction. 3. So that the direction of the magnetic flux generated by the detection lines in the X and Y directions or the direction of the current generated in the detection lines in the X and Y directions is opposite for each magnetic body or for each two or more adjacent magnetic bodies. 3. The position detection device according to claim 1, further comprising detection lines in the X direction and the Y direction. 4 Excitation lines in the X and Y directions or excitation lines in the X and Y directions corresponding to the magnetic bodies at both ends of the plurality of magnetic bodies in the X and Y directions arranged substantially parallel to each other.
Either one of the direction detection lines or X direction and Y direction
The position according to any one of claims 1 to 3, characterized in that the excitation line in the direction and the detection line in the X direction and the Y direction are arranged closer to the magnetic body. Detection device. 5. Claim 1, characterized in that the number of excitation lines disposed at both longitudinal ends of the magnetic body in the X direction and Y direction is greater than the number of excitation lines disposed in other parts. The position detection device according to any one of Items 4 to 4.