JPS61180322A - Position detector - Google Patents

Abstract

PURPOSE:To obtain a position detector having high operability and high accuracy by detecting the maximum induced voltage level when a tablet part where plural magnetic plates and conductor plates are laminated by means of a position designating bar magnet. CONSTITUTION:A tablet part 100 is formed by laminating three sets of magnetic matters obtained by enclosing the warp and the weft woven into plain meaning into an insulated material and four sheets of conductor plates in the prescribed order and into a prescribed form. Then a point A of the part 100 is designated by a position detecting bar magnet 400 with its N pole turned down. Thus the induced voltage levels V1-V8 are obtained on the detection lines of the direction X. Each of these levels V1-V8 is maximum right under the point A. These voltage levels are obtained from a multiplexer 301 and therefore the X coordinate value with which the induced voltage level is maximum is calculated by a position detecting circuit 500 to obtain the X coordinate value XS at the point A. The Y coordinate value YS is also obtained in the same way.

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) A conventional position detection device applies a pulse current to a drive coil provided at one end of a magnetostrictive transmission medium or at the tip of a position indicating pen to generate a magnetostrictive imaging wave in the magnetostrictive transmission medium. ,
From that point on, a processor or the like measures the time until an induced voltage based on the magnetostrictive imaging wave is detected in the detection coil provided at the tip of the positioning pen or at one end of the magnetostrictive transmission medium, and from this point, the positioning pen indicates the positioning pen. There was something that seemed to calculate the position. 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. The pen must be held perpendicular to the magnetostrictive transmission medium and very close to it when pointing. There were problems such as not being able to do so.

In addition, as another conventional position detection device, a plurality of drive lines and detection lines are arranged orthogonally to each other, and the drive lines are sequentially connected to the drive line VJ.
The induced voltage is detected by sequentially selecting the detection lines while applying current, and the position specified by the position indicator pen made of magnetic material such as ferrite is detected from the position of the detection line where a large induced voltage is induced. There was something I did. This device allows the positioning pen to be cordless, but
The resolution of the coordinate position is determined by the interval between the lines, and if the interval between the lines is made smaller to increase the resolution, the S/N ratio and stability will deteriorate, making it difficult to increase the resolution. It is difficult to detect the position directly above the input line, and the position indicating pen must be placed very close to the line, making it impossible to use a thick object placed on the input surface.

(Object of the invention) The present invention improves these conventional drawbacks,
It is an object of the present invention to provide a highly accurate position detection device that has a magnetic generator for specifying a position that is not connected anywhere, has good operability, is resistant to external guidance, and does not emit noise.

(Embodiment) FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the present invention. In the figure, 100 is a tablet unit, 200 is a driving current source, 301 and 302 are multiplexers, and 40
0 is a position designating magnetic generator, for example a bar magnet, and 500 is a position detection circuit.

As shown in FIG. 2, the tablet unit 100 is provided with a shield plate 110. a, magnetic plates 120a, 120b
.

Conductor plates 130a, 130b, magnetic plate 120C
, 120d.

Conductor plates 130G, 130d, magnetic plate 120e
, 120f.

It consists of 12 layers of shield plates 110b.

The shield plates 11oa and 1iob are printed circuit boards in which a non-magnetic metal plate, for example a copper plate 112, is attached to one side of an insulating substrate 111 made of glass epoxy or the like.

The magnetic plates 120a to 120f have a large number of insulating fibers 121 arranged substantially in parallel as shown in FIG. 3, and a plurality of elongated magnetic bodies 122 arranged at predetermined intervals between the insulating fibers 121. A warp group (or weft group) 123 and a weft group (or warp group) 12 consisting of a large number of insulating fibers 124.
5 are plain woven to form a woven fabric, and these are hardened with an insulating resin such as epoxy resin to form a plate. Here, as the insulating fibers 121 and 124, for example, glass fiber is used, and as the magnetic material 122, it is difficult to be magnetized even if a magnet is brought close, that is, the coercive force is small and the magnetic permeability (μ
), for example, an amorphous wire with a circular cross section and a diameter of about 0.1 mm. As the amorphous wire, for example, (Fe1-xCOx)75Si1
oB15 (atomic %) (X indicates the ratio of Fe and CO and takes a value of O to 1) is suitable. Although each fiber and the magnetic body are shown separated from each other in FIG. 3, they are actually constructed without any gaps, and in the illustrated example, two fibers are arranged between the magnetic bodies. However, in reality, the number of fibers required to maintain the spacing between the magnetic bodies is arranged.

As shown in FIG. 4, the conductor plates 130a to 130d are made by etching a printed circuit board 131, which is an insulating substrate made of glass epoxy or the like with a copper plate attached to one side, and has a plurality of (17 in the illustrated example) lands on both ends. Linear conductor 13 with holes
2.

120C between the magnetic plates 1208 and 120b.

120c and 120e and 12Of' are bonded and fixed by heat-pressing or an adhesive sheet, and other substrates are bonded and fixed by an adhesive sheet. At this time, the magnetic plate 12
Magnetic material 122 of 0a, 120c, 120e
along the Y direction, and the magnetic plates 120b and 1
The magnetic bodies 122 of 20d and 120f are arranged along the X direction, and the conductors of the conductor plates 130a and 130c are arranged along the Y direction.
The conductors of the conductor plates 130b and 130d are arranged in a direction perpendicular to the X direction.

In addition, as another manufacturing method, two magnetic plates are bonded together by heat pressure bonding, etc. so that the magnetic bodies are perpendicular to each other, a printed circuit board is bonded and fixed to both sides, and then a conductor is formed by etching. The above-mentioned shield plate 110a, 'a-shaped body plate 120a, 1
20b, a set of conductor plates 130a, a conductor plate 130b, magnetic plates 120c, 120d, a set of conductor plates 130c, and a conductor plate 130d, magnetic plates 120e, 120
f. A set of shield plates 110b may be created and these may be further bonded and fixed.

The thickness of the entire tablet portion 100 is actually about 2 to 4 mm, but only the thickness direction is shown enlarged in FIGS. 2 to 4.

Each of the conductors of the conductor plates 130b and 130d is connected to the vertically overlapping conductors by through-hole processing at one end of the land hole, and an excitation wire 140a in the X direction is wound around the magnetic body 122 in the magnetic body plate 120d. 1401 and detection lines 150a to 150h are alternately formed. Excitation line 140
The other ends of the conductor plate 130b side of the excitation lines a to 1401 are connected to the other ends of the adjacent excitation lines 140a to 1401 on the conductor plate 130d side, that is, they are connected in series. The end is connected to drive current #1200. In addition, the conductor plate 130 for each detection @ 150a to 150h
The other ends on the b side are respectively connected to the multiplexer 301, and the other ends on the conductor plate 130d side of the detection lines 150a to 150h are commonly grounded.

Each of the conductors of the conductor plates 130a and 130c is connected to the vertically overlapping conductors by through-hole processing at a land hole at one end, and an excitation wire 160a in the Y direction winds around the magnetic body 122 in the magnetic body plate 120C. 1601 and detection lines 170a to 170h are alternately formed. Excitation line 160
The other ends of the conductor plate 130a side of the excitation lines a to 1601 are connected to the other ends of the adjacent excitation lines 160a to 1601 on the conductor plate 130c side, that is, they are connected in series. The end is connected to a drive current source 200. Further, the other end of each of the detection lines 170a to 170h on the conductor plate 130a side is connected to the multiplexer 302,
The other ends of the detection lines 170a to 170h on the conductor plate 130C side are commonly grounded.

The drive current source 200 constantly supplies an alternating current (for example, a sine wave) with a predetermined period to the excitation lines 140a to 1401 and 160a to
1601. Moreover, the multiplexer 301,
302 selectively sends output signals of the detection lines 150a to 150h and 170a to 170h to the position detection circuit 5oo in accordance with a control signal from the position detection circuit 500.

In such a configuration, the excitation lines 140a to 14 are connected to the detection lines 1508 to 150h and 170a to 170h.
01 and 160a to 1601, an induced voltage is generated by the electric current 11 induction based on the alternating current flowing through them. Since this electric m induction is performed via the magnetic bodies 122 of the magnetic plates 120a to 120f, the higher the magnetic permeability of the magnetic bodies 122, the greater the voltage value of the induced voltage.

By the way, the magnetic permeability of the magnetic body 122 changes greatly depending on the magnetic bias applied from the outside. The state of the change varies depending on the composition of the magnetic material, the frequency of the alternating current, or the addition of heat treatment to the magnetic material, etc., and as shown in Figure 5, it becomes maximum when a predetermined amount of magnetic bias is applied. Can be set. Therefore, in this case, when the predetermined amount of magnetic bias is applied to the magnetic body 122, the excitation lines 140a to 140i, 160a to 1601
From detection lines 150a to 150h, 170a to 1
The voltage induced to 70h increases.

Now, in FIG. 1, the position specifying bar magnet 400 is located at a position A of the tablet unit 100, with its N pole facing down, at a distance X in the X direction from the detection line 150a and a distance y in the Y direction from the detection line 170a. , and the predetermined amount of magnetic bias is applied to the magnetic body 122.

At this time, induced voltages v1 to v8 as shown in FIG. 6 are generated in the detection lines 1508 to 150h in the X direction. In FIG. 6, the horizontal axis indicates the coordinate position in the X direction, where the positions of detection $150a to $150h are respectively X''-XB,
The vertical axis indicates the voltage value, and each voltage V −V8
has a maximum value (maximum value) directly below position A. Each of the voltages V
~v8 can be obtained from the multiplexer 301, so if the position detection circuit 500 calculates the X coordinate value at which the induced voltage becomes the maximum value from these values, the X coordinate value x 8 of the bar magnet 400 can be determined.

One calculation method for determining the coordinate value x is to approximate the waveform near the maximum value in FIG. 6 by an appropriate function, and then determine the coordinates of the maximum value of the function. For example, if the interval between each detection line 150a to 150h is ΔX and coordinates x3 to x5 in FIG. 6 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, V3=a (x3
1) V4=a (x4-x,) +b ・・−
--(2)V = a(X5-X5) +b -
...-(3). Here, a and b are constants (ago
).

Also, x4−×3=ΔX (4)
X 5 X 3 = 2ΔX...
...(5). (4), (5) to (2), (3)
) and rearranging it, x = x + Δx72 ((3v3-4v4+V5
)/(V3-2V4+V5))...(6) Therefore, the detection lines 150c, 150d,
150e induced voltage v3. v4. By calculating equation (6) in the position detection circuit 500 from v5 and the coordinate value x5 (known) of the detection line 150C, the X coordinate value x of the position specifying bar magnet 400 can be calculated.

Also, even if the bar magnet 40G is moved along the Y axis, the same
Coordinate values are obtained.

Further, induced voltages similar to those shown in FIG. 6 are obtained on the detection lines 170a to 170h in the Y direction, and the Y coordinate value y can be determined by the same calculation process as described above.

In addition, in the tablet portion 10G, the magnetic plate 12
0a, 120b, 120e, 120
As shown in FIG. 7, f constitutes a path for the magnetic flux generated around the excitation line by the magnetic body 122 therein, and is used to obtain larger electromagnetic induction, and does not need to be provided. Further, the shield plates 110a and 110b are provided to prevent noise from entering from the outside and emission of induced noise to the outside, and do not need to be provided.

Furthermore, the order in which the respective substrates are arranged is not limited to the above-mentioned order; for example, the magnetic plate 120b.

conductor plate 1301), magnetic plate 120d, conductor plate 130
d.

A position detection section in the X direction is constructed by stacking magnetic plates 120f in the order shown, a magnetic plate 120a, and a conductive plate 130a.

Magnetic plate 120C, conductor plate 130C, magnetic plate 120e
The Y-direction position detecting section may be constructed by stacking these in the order shown, and then these may be stacked one on top of the other. Furthermore, it is clear that by using only one of the X-direction or Y-direction position detecting sections, it is possible to configure a position detecting device for only one direction.

FIG. 8 shows a specific example of the drive current source 200.

In the figure, reference numeral 201 denotes an integrating circuit, which takes as an input signal a clock pulse (or a pulse obtained by frequency-dividing the clock pulse) of an arithmetic processing circuit of a position detection circuit 500, which will be described later, and integrates the clock pulse to convert it into a triangular wave signal. 202 is a bandpass filter that converts the triangular wave signal into a sine wave signal. 2
Reference numeral 03 denotes a power driver, which is composed of an operational amplifier and a current amplifier, and current-amplifies the sine wave signal to drive the excitation lines 140a to 140i, 160a to 1601.
Send to. Note that the reason why a clock pulse is used as the reference (input) signal is to synchronize with the position detection circuit 500.

FIG. 9 is a sectional view showing a specific example of the position designating magnetic generator 400, and FIG. 10 is an electric circuit diagram thereof.

In the figure, 401 is a pen-shaped container made of synthetic resin or the like, and a bar magnet 402 with a tapered tip is housed in one end of the pen-shaped container so as to be slidable in the axial direction. In addition, an infrared transmitting window 403 made of transparent plastic or the like is provided along the circumferential direction on the other end side of the container 401, and inside the window 403 there is a reflector 404 having a conical circumferential surface coated with chrome plating or the like. and an infrared light emitting diode 405 are housed. 406
．． Reference numeral 407 denotes an operation switch, and the operation switch 406 is attached to one side of the tip side of the container 401, and the operation switch 40
7 is attached to face the other end of the bar magnet 402.

Further, 408 is a signal generation circuit, 409 is a battery, and the container 4
It is stored in the appropriate place in 01. The signal generation circuit 408 converts a plurality of (three in this case) commands to the position detection circuit 500, such as measurement start and position input, into a plurality of code signals based on a combination of several pulse signals. It is equipped with a code signal generator 408b and a diode driving transistor 408c, and generates a code signal to drive the light emitting diode 405 in accordance with the on/off combination of the operation switches 406 and 407. When the operation switch 406 is turned on, an infrared signal indicating a code to start measurement is transmitted from the diode 405 through the reflector 404 and the transmission window 403, and the tip of the bar magnet 402 with the cover 410 attached is directly connected to the input surface. When pressed, the bar magnet 402 slides, turning on the switch 403, and an infrared signal indicating a position input code signal is emitted.

FIG. 11 is a circuit block diagram showing a specific configuration of the position detection circuit 500. In the same figure, when an infrared a signal indicating a measurement start code is emitted from the light emitting diode 405 of the position specifying magnetic generator 40G, the infrared signal is received by the infrared receiving diode 501, and then sent to the receiver. In step 502, the signal is amplified and waveform-shaped, converted into the original code signal, and further converted back into a measurement start command signal, and sent to the input buffer 503. The alj arithmetic processing circuit 504 reads the command signal from the input buffer 503, and when it recognizes the start of measurement, sends the IIJtll signal to the multiplexer 301 via the output buffer 5o5, and inputs the induced voltages of the detection lines 150a to 150h in the X direction to the amplifier 506. input sequentially. Each of the induced voltages is amplified by an amplifier 506, rectified by a detector 507 and converted to a DC voltage, further converted to a digital value by an analog-to-digital (A/D') converter 508, and then converted to a digital value via an input buffer 503. It is sent to the arithmetic processing circuit 504. The arithmetic processing circuit 504 temporarily stores each of the induced voltages (digital values) in a memory 509, and selects the induced voltage V having the maximum voltage value among them,
Detect. Roughly, the arithmetic processing circuit 504 is a memory 510
The induced voltage V from within, and the induced voltage vk- before and after it
1. Take out vk+1 and convert them to (6) above.
Voltage v3 in the equation. v4. As v5, the calculation process of equation (6) is performed to obtain the X coordinate value.

Next, the arithmetic processing circuit 504 sends a control signal to the multiplexer 302 via the output buffer 7505, sequentially inputs the induced voltages of the detection lines 170a to 170h in the Y direction, and performs the same processing as described above to obtain the Y coordinate value.

The X and Y coordinate values of the digital values obtained in this way are temporarily stored in the memory 509, but while the signal indicating the start of measurement is issued, the above-mentioned measurements and calculations are carried out for a predetermined period of time. It is repeated every time, and its value is updated.

Next, the position specifying magnetic generator 400 transmits an infrared signal indicating a measurement start code, and the light receiving diode 501
, receiver 502, and input buffer 503, the X and Y coordinate values of the digital value at that time are input to the digital display (not shown) via the output buffer 510. or sent to a computer (not shown) for processing, or digital-to-analog (D
/A) It is converted into an analog signal via the converter 511 and processed.

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 5 mm. Further, the position specifying magnetic generator is not limited to a bar magnet, and may be a plate, a ring, an inner body, etc., or an electromagnet.

(Effects of the Invention) As explained above, according to the present invention, the magnetic plate can be configured extremely thin, the tablet part can be thin and easily mass-produced, and it can be provided at low cost, and the excitation line and detection The change in magnetic flux between the magnetic wire and the wire occurs only within the magnetic body, and the coupling is tight, the detection voltage is large, the S/N ratio is good, and it is less susceptible to external induction and generates little external induction noise. 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 magnetic generator for positioning close to the magnetic material, allowing for a larger effective reading height and making the tablet part thinner. In addition to what can be done, the position can be specified from the back side, and it can also be sandwiched between metals other than ferromagnetic materials. 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 drawings]

The drawings are for explaining the present invention. FIG. 1 is a partially cutaway exploded perspective view showing one embodiment of the present invention, FIG. 2 is a diagram showing the specific structure of the tablet portion, and FIG. Figure 4 is a perspective view of the conductor plate, Figure 5 is a characteristic diagram of magnetic bias versus magnetic permeability, and Figure 6 is an example of the induced voltage generated in each detection line in the X direction. 7 is an explanatory diagram showing the state of magnetic flux around the excitation line, FIG. 8 is an electric circuit diagram showing a specific example of a drive current source, and FIG. 9 is a specific example of a magnetic generator for position specification. FIG. 10 is an electric circuit diagram thereof, and FIG. 11 is a circuit block diagram showing a specific configuration of the position detection circuit. 100... Tablet part, 200... Drive current source,
301.302... Multiplexer, 400... Magnetic generator for position specification, 500... Position detection circuit, 11
0a. 110b...shield plate, 120a-120f...
Magnetic plate, 121, 124... Insulating fiber, 122.
...Magnetic material, 130a to 130d, 13 body plates, 140
a~140i. 160a ~160 i--excitation line, 150a ~1
50h. 170a to 170h...detection line.

Claims (6)

[Claims] (1) A warp group (or weft group) consisting of a large number of insulating fibers and a plurality of long magnetic bodies arranged at predetermined intervals between the insulating fibers, and a weft group consisting of a large number of insulating fibers. (or a group of warp yarns) to form a fabric-like plain weave, and harden them with an insulating resin to form a plate-like magnetic material plate, and two conductor plates formed by forming a plurality of linear conductors almost parallel to each other. The two conductor plates are stacked on both sides of the magnetic plate so that the conductor and the magnetic body are perpendicular to each other, and the two conductor plate-like conductors are connected vertically, and the excitation line and the magnetic body are alternately connected. A tablet portion serving as a detection line, a driving current source that applies an alternating current at a predetermined period to each of the excitation lines, a position designating magnetic generator that generates a steady magnetic field, and an induced voltage induced in each of the detection lines. Take out the
A position detection device comprising a position detection circuit that calculates designated coordinates of the position designation magnetic generator from these. (2) Another magnetic material plate is arranged on both outer sides of the conductor plate so that the magnetic material thereof is parallel to the magnetic material of the magnetic material plate between the conductor plates. Position detection device. (3) The position detection device according to claim 1 or 2, characterized in that shield plates made of non-magnetic metal are disposed on both outer sides of the conductor plate. (4) A warp group (or weft group) consisting of a large number of insulating fibers and a plurality of long magnetic bodies arranged at predetermined intervals between the insulating fibers, and a weft group consisting of a large number of insulating fibers. (or a group of warp threads) are plain-woven into a woven fabric, and these are hardened with an insulating resin to form a plate shape. Two magnetic plates, and a plurality of linear conductors formed almost parallel to each other make four sheets. and a conductor plate, the two magnetic plates are arranged so that the magnetic bodies are along the X and Y directions, and two conductor plates are placed on both sides of the magnetic plate whose magnetic body is along the X direction. The conductor is arranged so as to be perpendicular to the X direction, and further, two conductor plates are arranged on both sides of the magnetic plate whose magnetic material is along the Y direction, and the conductor is arranged perpendicularly to the Y direction. A tablet section in which conductors in the same direction are connected vertically to form excitation lines and detection lines in the X and Y directions alternately, and a drive current that applies an alternating current at a predetermined period to each of the excitation lines in the X and Y directions. source, a position designating magnetic generator that generates a steady magnetic field, and the induced voltages induced in each of the detection lines in the X and Y directions, and from these, calculate the designated coordinates of the position designating magnetic generator. A position detection device consisting of a position detection circuit. (5) A conductor plate in which the conductor is arranged so as to be orthogonal to the X direction, and another magnetic plate is placed on both sides of the conductor plate so that the magnetic material is along the X direction, and the conductor is arranged in a manner that the conductor is orthogonal to the Y direction. 5. The position detecting device according to claim 4, further comprising another magnetic plate placed on both outer sides of the plate so that the magnetic plates extend along the Y direction. (6) The position detection device according to claim 4 or 5, characterized in that shield plates made of non-magnetic metal are disposed on both outer sides of the conductor plate.