JPH0210968B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a position detection device that can easily and accurately detect the coordinate values of any indicated position.

(Prior Art) A conventional position detection device applies a pulse current 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, and A processor or the like measures the time until an induced voltage based on the magnetostrictive vibration 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 the indicated position of the positioning pen is calculated. In some cases, a plurality of drive lines and detection lines are arranged orthogonally to each other, and the induced voltage is detected by sequentially passing current through the drive lines and sequentially selecting the detection lines. There was a device in which a position specified by a position indicating pen having a position indicator was detected from the position of a detection line where a large induced voltage was induced.

(Problems to be Solved by the Invention) Although the former device has relatively good position detection accuracy, it is susceptible to guidance from other devices and may malfunction, or may even become a source of noise. In the latter device, 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 signal-to-noise ratio and stability deteriorate, making it difficult to increase the resolution. It is difficult to detect the position directly above the intersection of the lines, and in addition, with these devices, the accuracy of position detection will be extremely reduced or the detection will be difficult if the position indicating pen is not brought very close to the magnetostrictive transmission medium or the detection line. Therefore, there was a problem that so-called three-dimensional position detection including the height direction on the input board surface was impossible.

The present invention solves the conventional problems as described above, and provides a high-precision position detection device that has a magnetic generator for position specification that is not connected anywhere, has good operability, and is resistant to external induced noise, etc. It is an object of the present invention to provide a position detection device capable of detecting coordinate values in the Z direction as well as coordinate values in the X and Y directions.

(Structure of the Invention) In order to solve the above-mentioned problems, the present invention has a flat magnetic body 11 or two sets of magnetic body pieces each formed by arranging a plurality of elongated magnetic body pieces substantially parallel to each other. Excitation lines 122a to 122i and 132a to 132a are arranged in the X direction and the Y direction so as to continuously cover both the upper and lower surfaces of the magnetic body 16, which are stacked at right angles.
132i and detection lines 123a to 123h and 133
a to 133h arranged alternately, a drive current source 20 that applies an alternating current at a predetermined period to each excitation line in the X direction and the Y direction, and each detection device in the X direction and the Y direction. X-direction and Y-direction signal selection means 31, 32 connected to the lines, respectively.
, a position designating magnetic generator 40 that applies a local magnetic bias to the magnetic body 11 or 16 and is not connected anywhere, and the position designation from each induced voltage taken out from the X-direction and Y-direction signal selection means. Calculate the coordinate values in the X and Y directions of the designated position by the magnetic generator, or in addition, calculate the largest voltage value among the induced voltages in the X and Y directions at least one preset threshold value. The present invention is characterized by comprising a processing device 50 that calculates the Z-direction coordinate value of the position designated by the position designating magnetic generator by comparing with the position designation magnetic generator.

(Embodiment) FIG. 1 shows the main part configuration of an embodiment of the present invention, in which 10 is a tablet section, 20 is a drive current source, 31 and 32 are signal selection means, for example, a multiplexer, and 40 is a A magnetic generator for position designation, for example a bar magnet, 50 is a processing device.

The tablet part 10 includes a flat magnetic body 11 and an
It consists of a direction conductor section 12 and a Y direction conductor section 13. The magnetic material 11 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 amorphous alloy, for example, Fe ₇₉ B ₁₆ Si ₅ (atomic %) (coercive force
0.2Oe, magnetic permeability (μ) = 14000), etc. can be used.
Moreover, although the magnetic body 11 is in the shape of a flat plate (sheet),
Amorphous alloys can be manufactured to be as thin as 20 to 50 μm, so they may be used as they are.

The X-direction conductor section 12 is made up of a large number of linear conductors such as copper wires laminated in parallel with a plastic film 121 or the like, and the linear conductors are connected to excitation lines 122a to 122i and detection lines 123a to 12.
It seems to constitute 3h. This X-direction conductor portion 12 is folded in two near the approximate center in the longitudinal direction, and the magnetic material 11 is housed in between. Each excitation line 1 on the side of the portion 12b located under the lower surface 11b of the magnetic body 11 of the X-direction conductor portion 12
22a, 122b, 122c, 122d, 122
One end of e, 122f, 122g, 122h is a portion 12a located above the upper surface 11a of the magnetic body 11.
Side excitation lines 122b, 122c, 122d, 12
2e, 122f, 122g, 122h, 122i
are respectively connected to one end of the excitation line 122a, that is, the excitation line 122a
122i are connected in series, and the other end of the excitation line 122a and the other end of the excitation line 122i are connected to the drive current source 20. In addition, each excitation line 122a to 122i
are arranged parallel to each other at predetermined intervals in a direction perpendicular to the X direction, that is, along the Y direction. One end of each of the detection lines 123a to 123h on the portion 12a side is connected to the multiplexer 31, and one end on the portion 12b side is commonly grounded. In addition, each detection line 123a to 123h is connected to an excitation line 122, respectively.
They are arranged parallel to each other between each of a to 122i.

The Y-direction conductor portion 13 is made of plastic film 1
31, excitation lines 132a to 132i, and detection line 133
a to 133h, and its detailed structure is the same as that of the X-direction conductor section 12. As shown in FIG. 2, the upper surface 1 of the magnetic body 11 of the Y direction conductor section 13
The portion 13a located above 1a is the X direction conductor portion 1
A portion 13 located above the portion 12a of No. 2 and below the lower surface 11b of the magnetic body 11 of the Y-direction conductor portion 13
b is arranged so as to be above the portion 12b of the X-direction conductor portion 12. In addition, each excitation line 132a to 132i
are connected to the drive current source 20, and each detection line 133a
~133h are connected to multiplexer 32.
Note that the arrangement of the X-direction conductor portion 12 and the Y-direction conductor portion 13 is such that the portion 12a is located above the portion 13a,
The portion 12b may be positioned above the portion 13b. In addition, these tablet parts 10 are made of non-magnetic metal, for example, an aluminum plate 14, as shown in FIG.
The upper part may be covered with In addition, 15
is a holding plate made of synthetic resin or the like.

The drive current source 20 always sends out an alternating current of a predetermined period (the alternating current here includes all of sine waves, rectangular waves, triangular waves, etc.) to the excitation lines 122a to 122i and 132a to 132i. Further, the multiplexers 31 and 32 operate on the detection lines 123a to 123h and 133 according to the control signal from the processing device 50.
The output signals of a to 133h are selectively sent to the processing device 50.

In such a configuration, the detection lines 123a to 1
The excitation line 1 is connected to 23h and 133a to 133h.
An induced voltage is generated by electromagnetic induction based on the alternating current flowing through 22a to 122i and 132a to 132i. Since this electromagnetic induction occurs via the magnetic body 11, the higher the magnetic permeability of the magnetic body 11, the greater the voltage value of the induced voltage. By the way, the magnetic permeability of the magnetic body 11 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, heat treatment applied to the magnetic material, etc.
As shown in the figure, it can be set so that it becomes maximum when a predetermined amount of magnetic bias is applied. Therefore, in this case, if a magnetic bias of the predetermined amount is applied to the magnetic body 11, the excitation lines 122a to 122
i, 132a to 132i to detection lines 123a to 1
The voltage induced to 23h, 133a to 133h increases.

Now, in FIG. 1, the position specifying bar magnet 40 is
Distance in the X direction from the detection line 123a with the pole facing down
x _s , and is located on position A of the Y-direction conductor section 13 separated by a distance y _s in the Y direction from the detection line 133a (the distance in the Z direction is 0), and applies a magnetic bias of about the predetermined amount to the magnetic material. 11.

At this time, induced voltages _V1 to _V8 as shown in FIG. 5 are generated in the detection lines 123a to 123h in the X direction. In FIG. 5, the horizontal axis is the detection line 123a to 1
The coordinate positions in the X direction are shown with the positions of 23h being x ₁ to x ₈ , respectively, and the vertical axis shows the voltage value, and each of the voltages V ₁ to _{V 8} has a maximum value (maximum value) directly below position A.
becomes. Each of the voltages V ₁ to _{V 8} is supplied to multiplexer 3.
1, the X coordinate value _xs of the bar magnet 40 can be determined by calculating and determining the X coordinate value at which the induced voltage becomes the maximum value using the processing device 50.

As one of the calculation methods for determining the coordinate value x _s , the fifth
There is a method of approximating the waveform near the maximum value in the figure with an appropriate function and finding the coordinates of the maximum value of that function. For example, if the interval between each detection line 123a to 123h is Δx and the coordinates x ₃ to x ₅ in FIG. 5 are approximated by a quadratic function (indicated by a solid line in the figure), the calculation can be performed as follows. Can be done. 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 ( x ₅ −x _s ) 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 123c, 123d, 1
The processing device 50 uses the voltages V ₃ , V ₄ , V ₅ induced in 23e and the coordinate value x ₃ (known) of the detection line 123c.
The X coordinate value of the bar magnet 40 can be calculated by calculating equation (6). Further, even if the bar magnet 40 is moved along the Y axis, the same X coordinate value can be obtained.

Further, induced voltages similar to those shown in FIG. 5 are obtained on the detection lines 133a to 133h in the Y direction, and the Y coordinate value _ys can be determined by the same calculation process as described above.

In addition, as mentioned above, in order to specify the position, it is sufficient to locally apply a magnetic bias of several tens of e to the magnetic body 11, so the position specifying bar magnet 40 may be separated from the magnetic body 11 by some distance in the Z direction. It can also be used. Here, the amount of magnetic bias (that is, the magnetic field strength) applied to the magnetic body 11 from one end of the N-pole side of the position specifying bar magnet 40 is between the magnetic body 11 and the bar magnet 40.
It is inversely proportional to the square of the distance between the two ends of the line, that is, the distance in the Z direction. Therefore, Z of the position designating bar magnet 40
When the distance in the direction is 0, for example, when one end of the bar magnet 40 comes into contact with the input surface 70 normally formed on the upper part of the tablet part 10 as shown in FIG. If the magnetic field strength of the bar magnet 40 is set so that the magnetic bias applied to the bar magnet 40 has a value that maximizes the magnetic permeability, the magnetic permeability decreases in inverse proportion to approximately the square of the distance of the bar magnet 40 in the Z direction. Detection lines 123a to 123h, 133a to 13
The induced voltage to 3h is reduced. In Figure 5,
V ₃ to _{V 5} indicate induced voltages when one end of the N pole side of the bar magnet 40 is held at the position A at a short distance (about 5 mm) in the Z direction.

The induced voltage value V _s at the indicated position is the magnetic material 11
, the magnetic field strength of the bar magnet 40, and the distance in the Z direction. Therefore, if the voltage _Vs is known, the distance (position) of the bar magnet 40 in the Z direction can be calculated. However, in reality the voltage
Since it is difficult to calculate V _s from the voltages V ₃ to _{V 5} using a formula, it is not possible to know the exact distance of the bar magnet 40 in the Z direction. Therefore, instead of the voltage V _s , take the voltage of the detection line closest to the indicated position, that is, the largest voltage value among the induced voltages V ₁ to V ₈ (V ₄ in the example in Figure 5), and set several of these in advance. It is compared with the set threshold voltage _VT , and from the result, the approximate distance of the bar magnet 40 in the Z direction can be determined. Note that even if the distance in the Z direction is the same, there is a considerable difference in the voltage value of the largest induced voltage between when the indicated position of the bar magnet 40 is located near the middle of each detection line and when it is located near each detection line. However, the difference can be set in advance by taking this difference into account, or the difference can be reduced by increasing the number of detection lines and excitation lines and reducing the spacing between them.

FIG. 7 shows a specific example of the drive current source 20. In the figure, reference numeral 21 denotes a function generator, such as Intersil IC 8038, which outputs a sine wave signal of a predetermined frequency determined by the values of capacitor C and resistor R. A power driver 22 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 122a to 122i and 132a to 132i.

FIG. 8 is a sectional view showing a specific example of the position specifying magnetic generator 40, and FIG. 9 is an electric circuit diagram thereof. In the figure, reference numeral 41 denotes a pen-shaped container made of synthetic resin or the like, and a hollow slide tube 42 made of synthetic resin or the like with a tapered tip is accommodated in one end of the pen-shaped container so as to be slidable in the axial direction. Further, 43 is a bar magnet attached to one end of the container 41 so as to be housed in the slide tube 42. Further, 44 is an operation switch attached to a position that can be operated from the side of the container 41, 45 is an ultrasonic signal transmitter, and 46 is an ultrasonic wave transmitter, which is attached to a suitable place in the container 41 together with a battery 47. It is stored. Said container 4
1, touch the tip of the hollow slide tube 42 to the input surface to specify the position, and operate the switch 44, the oscillation circuit 45a in the transmitter 45 and the amplifier 4
5b is activated, and the transmitter 46 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. At this time, when the container 41 is strongly pressed against the input surface, the slide tube 42 slides into the container 41 and the tip of the bar magnet 43 approaches the input surface. The tip of the bar magnet 43 remains protruded due to the repulsive force and moves away from the input surface, so that the indicated position of the bar magnet 43 in the Z direction can be easily changed.

FIG. 10 is a circuit block diagram showing a specific configuration of the processing device 50. In the figure, when an ultrasonic signal indicating the start of measurement is transmitted from the above-mentioned transmitter 46, the ultrasonic signal is received by a receiver 51,
Furthermore, the signal is amplified and waveform-shaped by the receiver 52 and sent to the input buffer 53. The arithmetic processing unit 54 reads the measurement start signal from the input buffer 53,
When the start of measurement is recognized, a control signal is sent to the switching circuit 56 and the multiplexer 31 via the output buffer 55, and the induced voltages of the detection lines 123a to 123h in the X direction are sequentially input to the amplifier 57. Each of the induced voltages is amplified by an amplifier 57, rectified by a detector 58, converted into a DC voltage, further converted into a digital value by an analog-digital (A/D) converter 59, and processed through an input buffer 53. The signal is sent to circuit 54. The arithmetic processing circuit 54 temporarily stores each of the induced voltages (digital values) in the memory 60, and detects the induced voltage V _k (k=1, 2...8) having the maximum voltage value among them. Further, the arithmetic processing circuit 54 receives the induced voltage from within the memory 60.
Take out V _k and the induced voltages V _k-1 and V _k+1 before and after it,
These are respectively the voltages V ₃ , V ₄ , and
As _V5 , perform the arithmetic processing of equation (6) to obtain the X coordinate value. On the other hand, the maximum induced voltage V _k and a predetermined threshold voltage stored in the threshold memory 61 in advance
V _T and the Z coordinate value of the bar magnet 40 is determined.

Next, the arithmetic processing circuit 54 sends a control signal to the switching circuit 56 and the multiplexer 32 via the output buffer 55, and sends a control signal to the detection lines 133a to 133h in the Y direction.
The induced voltages are sequentially input, and the same processing as described above is performed to obtain the Y coordinate value.

The digital value X obtained in this way,
The Y and Z coordinate values are sent via output buffer 62 to a digital display (not shown) for display, or sent to a computer (not shown) for processing, or digital-to-analog (D/A). It is converted into an analog signal via a converter 63 and processed. The Z coordinate value is used not only when placing a three-dimensional object (limited to extremely low height objects) on the input surface and inputting its shape, but also as a parameter for the line thickness of the input figure. It can also be used. It goes without saying that the Z coordinate value can be determined from the induced voltage in the Y direction.

Further, the numbers of excitation lines and detection lines in the embodiments are merely examples, and it goes without saying that the numbers are not limited thereto. Further, 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. Further, the magnetic generator for specifying the position is not limited to a bar magnet, and may be a plate, ring, square body, etc., or may be an electromagnet.

In the above embodiment, the signal indicating the start of measurement was transmitted from the position specifying magnetic generator 40 to the processing device 50 using an ultrasonic signal in order to make the position specifying magnetic generator 40 cordless and improve operability. However, it goes without saying that the electric signal may be transmitted as it is using a code. Furthermore, since the signal indicating the start of measurement is simply for making the arithmetic processing circuit 54 recognize the timing of coordinate detection, it is not necessary to send it from the magnetic generator 40, but rather from the keyboard provided in the processing device 50 itself. A signal for recognizing the timing may be sent from another switch circuit.

FIG. 11 shows another embodiment of the magnetic material of the present invention. In the same figure, reference numeral 16 is a magnetic material, for example, a plurality of amorphous wires (magnetic material pieces) 161 with a diameter of 0.13 mm are arranged at predetermined intervals (1 to 2
Two sheets 163 are arranged approximately parallel to each other with a distance of This increases the detection accuracy.

(Effects of the Invention) As explained above, according to the present invention, two sets of magnetic material pieces each formed by arranging a flat magnetic material or a plurality of elongated magnetic material pieces substantially parallel to each other are arranged at right angles to each other. a tablet portion in which excitation lines and detection lines are arranged alternately in the X direction and the Y direction so as to continuously cover both upper and lower surfaces of magnetic bodies configured by overlapping each other in the X direction and the Y direction; a drive current source that applies an alternating current with a predetermined period to each excitation line; a signal selection means in the X and Y directions connected to each of the detection lines in the X and Y directions; and local magnetism in the magnetic body. A position designating magnetic generator to which a bias is applied and not connected to any other location, and the X direction of the designated position by the position designating magnetic generator from each induced voltage taken out from the X direction and Y direction signal selection means.
Equipped with a processing device that calculates the coordinate values in the direction and Y direction, the magnetic flux change between the excitation line and the detection line occurs only within the magnetic body, and the coupling is tight, resulting in a large detection voltage and a good signal-to-noise ratio. In addition, it is less susceptible to external induction and generates less external induction noise.Furthermore, the magnetic generator for position specification does not need to send timing signals etc. for position detection to the equipment side, making it easier to communicate with the equipment. The cable can be made cordless, and the cord will not break, become tangled, or become loose due to fatigue. Therefore, it is easy to operate, and the magnetic generator for position specification can be placed in any position. Can be easily moved and
Because the excitation lines and detection lines in the X and Y directions are arranged around a common magnetic body, the distances between the excitation lines and detection lines in the X and Y directions and the magnetic generator for position specification are almost the same. , its detection output is
It is almost the same in both the direction and the Y direction, therefore, the detection accuracy is improved, and the position can be specified by simply applying a slight magnetic bias to the magnetic material, so it is not necessary to place the magnetic generator for position specification close to the tablet. It is okay to leave a distance of several centimeters or more,
Further, an object other than a magnetic material may be interposed, and even in these cases, the position can be detected with high resolution.

In addition, while calculating the coordinate values in the X direction and Y direction of the designated position by the position designating magnetic generator,
A processing device that calculates the Z-direction coordinate value of the specified position by the position-specifying magnetic generator by comparing the largest voltage value among the induced voltages in the X-direction or the Y-direction with at least one preset threshold value. In addition to the above-mentioned effects, it is possible to input the so-called two-dimensional coordinate values in the X and Y directions as well as the coordinate values in the Z direction perpendicular to these, making it possible to directly input the shape of a three-dimensional object. or
Effects such as being able to change parameters other than two-dimensional coordinate values together with position designation can be obtained.

[Brief explanation of drawings]

The drawings are for explaining the present invention, and FIG. 1 is a partially cutaway exploded perspective view showing one embodiment of the present invention, FIG. 2 is a cross-sectional view of the tablet portion along the excitation line in the Y direction, and FIG. Figure 4 is a partially cutaway perspective view showing the tablet part covered with an aluminum plate, Figure 4 is a characteristic diagram of magnetic bias versus magnetic permeability, and Figure 5 is an example of the induced voltage generated in each detection line in the X direction. 6 is an explanatory diagram showing the state of the magnetic flux applied to the magnetic material from the bar magnet for position designation, Figure 7 is an electric circuit diagram showing a specific example of the drive current source, and Figure 8 is a diagram showing the position designation. Cross-sectional view showing a specific example of a magnetic generator for use, No. 9
10 is a circuit block diagram showing a specific configuration of the processing device, and FIG. 11 is a partially cutaway perspective view showing another embodiment of the magnetic material. 10... Tablet part, 20... Drive current source,
31, 32... Multiplexer, 40... Magnetic generator for position specification, 50... Processing device, 11, 16
...Magnetic material, 122a-122i, 132a-1
32i...excitation line, 123a to 123h, 133
a~133h...Detection line.

Claims (1)

[Claims] 1. A flat magnetic material or a group of magnetic material pieces 2 formed by arranging a plurality of elongated magnetic material pieces substantially parallel to each other.
a tablet portion in which excitation wires and detection wires are arranged alternately in the X direction and the Y direction so as to continuously cover both upper and lower surfaces of a magnetic body formed by overlapping pairs of magnetic materials in a perpendicular direction; and a drive current source that applies an alternating current with a predetermined period to each excitation line in the X and Y directions; signal selection means in the X and Y directions connected to each of the detection lines in the X and Y directions, respectively; a position designating magnetic generator that applies a local magnetic bias and is not connected to any other location; and a position designating magnetic generator that applies a local magnetic bias and is not connected to any part; and a processing device that calculates coordinate values in the Y direction. 2. The position detection device according to claim 1, wherein the tablet portion is covered with a non-magnetic metal. 3 Magnetic material piece group 2 made of a flat magnetic material or a plurality of long magnetic material pieces arranged substantially parallel to each other
a tablet portion in which excitation wires and detection wires are arranged alternately in the X direction and the Y direction so as to continuously cover both upper and lower surfaces of a magnetic body formed by overlapping pairs of magnetic materials in a perpendicular direction; and a drive current source that applies an alternating current with a predetermined period to each excitation line in the X and Y directions; signal selection means in the X and Y directions connected to each of the detection lines in the X and Y directions, respectively; a position designating magnetic generator that applies a local magnetic bias and is not connected to any other location; and a position designating magnetic generator that applies a local magnetic bias and is not connected to any part; and Y-direction coordinate values, and by comparing the largest voltage value of each induced voltage in the X-direction or Y-direction with at least one preset threshold value, the magnetic generator for position designation 1. A position detection device comprising: a processing device for determining a Z-direction coordinate value of a specified position. 4. The position detection device according to claim 3, wherein the tablet portion is covered with a non-magnetic metal.