JPH0355847B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position detection device that detects a position on a plane using magnetostriction.

[Conventional technology]

As a conventional device of this type, a position detection device having a structure as shown in FIG. 8, for example, is known.

In the figure, reference numeral 1 denotes a magnetostrictive metal plate made of a metal with good magnetostriction efficiency, such as nickel, and is usually in the shape of a rectangular thin plate. Assuming XY coordinates as shown on this magnetostrictive metal plate 1, an X-axis one-turn coil 2 is placed on one side in the direction perpendicular to the X-axis.
is wound, and a Y-axis one-turn coil 3 is wound around one side in a direction perpendicular to the Y-axis. One ends of the X-axis and Y-axis one-turn coils 2 and 3 are commonly grounded, and the other ends are connected to a processing section (not shown). Further, a detection coil 4 movable on the surface of the magnetostrictive metal plate 1 is provided, and this detection coil 4 is connected to a processing section (not shown) via a signal line 5.

Now, assume that the coil center of the detection coil 4 is placed on the magnetostrictive metal plate 1 at a distance x from the X-axis one-turn coil 2 and y from the Y-axis one-turn coil 3. In this state, when a high voltage pulse is applied from the processing section to the X-axis one-turn coil 2, an instantaneous magnetic force is generated on the magnetostrictive metal plate 1 directly below the coil in a direction perpendicular to the X-axis one-turn coil 2, that is, in the X-axis direction. Due to this magnetic force, the magnetostrictive metal plate 1 is subjected to instantaneous magnetostriction immediately below the X-axis one-turn coil 2, thereby generating an instantaneous magnetostrictive wave. This generated instantaneous magnetostrictive wave becomes a plane wave and propagates through the magnetostrictive metal plate 1 at a constant speed determined by the material of the magnetostrictive metal plate 1. When this instantaneous magnetostrictive wave reaches the detection coil 4, an induced voltage (magnetostrictive wave pulse) due to the magnetostrictive wave is generated in the detection coil 4. Therefore, if the time from the time when the high voltage pulse is applied to the X-axis one-turn coil 2 to the time when the induced voltage is generated in the detection coil 4 is measured by a processing section (not shown), this time and the propagation speed of the magnetostrictive wave can be calculated. The distance x from the X-axis one-turn coil 2 to the detection coil 4 can be determined from . Similarly, Y-axis one-turn coil 3
The distance y from the detection coil 4 to the detection coil 4 can also be determined.

[Problem that the invention seeks to solve]

By the way, in order to generate an instantaneous magnetostrictive wave in the magnetostrictive metal plate 1 and to generate an induced voltage of a detectable magnitude in the detection coil 4 by the instantaneous magnetostrictive wave propagating in the magnetostrictive metal plate 1, requires that a bias magnetic field in a certain direction be applied to the magnetostrictive metal plate 1. That is, assuming that the traveling direction of the instantaneous magnetostrictive waves is shown by arrow 6 in FIG. 9, the preferred direction of the bias magnetic field is parallel to the traveling direction as shown by arrow 7 in the same figure, A bias magnetic field in a direction perpendicular to the traveling direction of the instantaneous magnetostrictive wave (magnetic field in the direction shown by arrows 8 and 9 in the figure), which does not contain any components, cannot generate a sufficiently large dielectric voltage.

Therefore, in the conventional position detection device shown in FIG. 8, the magnetostrictive metal plate 1 is magnetized so that the direction of the bias magnetic field forms an angle of 45 degrees with the X axis at all points on the magnetostrictive metal plate 1.

Therefore, the conventional position detection device has the disadvantage that the magnetostrictive metal plate 1 itself must be magnetized in a predetermined direction, and that the magnetization may weaken or the direction of magnetization may be disturbed by the influence of an external magnetic field. In this case, the detection accuracy is poor, and the magnetostrictive metal plate 1 must be periodically magnetized using a magnet bar or the like in order to always maintain the magnetization direction in a predetermined direction.

The present invention solves these conventional drawbacks, and its purpose is to eliminate the need to magnetize the magnetostrictive metal plate 1 in advance and to avoid being affected by the magnetization of the magnetostrictive metal plate 1 by an external magnetic field. An object of the present invention is to provide a position detection device that can perform accurate position detection.

[Means for solving problems]

In order to achieve the above object, the present invention includes a magnetostrictive metal plate, a permanent position detection device that is attached near an end of the magnetostrictive metal plate, and that magnetizes the area of the magnetostrictive metal plate at the attached position substantially radially. a plurality of fixed-side electromagnetic coils each having a magnet as a magnetic core; and a permanent magnet having a permanent magnet as a magnetic core that can be moved to any position on the surface of the magnetostrictive metal plate and magnetizes a region of the magnetostrictive metal plate at the moved position substantially radially. a moving side electromagnetic coil; an electric pulse applying means for applying an electric pulse to one of the plurality of fixed side electromagnetic coils or the moving side electromagnetic coil; and the magnetostrictive metal plate by the electric pulse applied by the electric pulse applying means. magnetostrictive pulse detection means for detecting the induced voltage generated in the other electromagnetic coil by the magnetostrictive vibration waves generated in the magnetostrictive pulse detection means; and a time for determining the time difference between the time point at which the induced voltage is detected by the magnetostrictive pulse detection means and a predetermined time point. It consists of a measuring means.

In a preferred embodiment of the present invention, the electric pulse applying means applies an electric pulse to the moving electromagnetic coil, and the magnetostrictive pulse detecting means detects induced voltages generated in each of the plurality of fixed electromagnetic coils. will be adopted. In this case, the time measuring means is configured to set the time point at which an electric pulse is applied to the moving side electromagnetic coil as the predetermined time point, and calculate the time difference from this time point to the time point at which the induced voltage of each of the fixed side electromagnetic coils is detected. Alternatively, the time point at which induced voltage is first detected among the plurality of fixed electromagnetic coils is defined as the predetermined time point, and the time difference from this time point to the time point at which induced voltage is detected in the remaining fixed electromagnetic coils is calculated. The configuration etc. will be adopted. In another embodiment, the electric pulse applying means sequentially applies electric pulses to the fixed electromagnetic coil, and the electromagnetic pulse detecting means detects an induced voltage generated in the moving electromagnetic coil, and measures the time. The means defines the predetermined time as a point in time when an electric pulse is applied to each of the fixed electromagnetic coils,
A configuration is adopted in which a time difference is calculated from the time point to the time point when the induced voltage of the moving electromagnetic coil is detected.

[Effect]

Taking as an example an embodiment of the present invention in which a moving electromagnetic coil is used for generating magnetostrictive waves and a plurality of fixed electromagnetic coils are used for detecting magnetostrictive waves, the operation will be explained. When an electric pulse is applied to the moving electromagnetic coil by the electric pulse application means with the magnetostrictive metal plate region directly under the moving electromagnetic coil radially magnetized, a sufficiently large instantaneous magnetostrictive wave is generated directly under the moving electromagnetic coil. occurs,
This generated instantaneous magnetostrictive wave propagates through the magnetostrictive metal plate in all directions, that is, in the radial direction, and when it reaches the fixed electromagnetic coil, an induced voltage is generated in the fixed electromagnetic coil. In this case, the magnetostrictive metal plate directly below the fixed electromagnetic coil is also magnetized in the almost radial direction by the permanent magnet of the fixed electromagnetic coil, so no matter what direction the instantaneous magnetostrictive wave arrives from, it will not match the traveling direction of the incoming magnetostrictive wave. A parallel bias magnetic field is present to generate an induced voltage of sufficient magnitude. The induced voltage generated in the fixed electromagnetic coil is detected by the magnetostrictive pulse detection means, and the time difference between the time when the induced voltage is detected and a predetermined time is determined by the time measurement means. The position where the moving side electromagnetic coil is placed is calculated based on this time difference.

〔Example〕

FIG. 1 is a plan view of essential parts of an embodiment of the present invention, in which 10 is a magnetostrictive metal plate, 11 is a moving electromagnetic coil, and 12 to 15 are stationary electromagnetic coils.

The magnetostrictive metal plate 10 is made of a metal plate with good magnetostrictive effect, such as a thin nickel plate, and has a rectangular shape in this embodiment. 4 on the surface of the magnetostrictive metal plate 10
Fixed electromagnetic coils 12 to 15 are attached to the corners, and a movable electromagnetic coil 11 that can be freely moved on the surface of the magnetostrictive metal plate 10 is provided. These electromagnetic coils 11-15 are connected to a processing section described later by signal lines 16-20.

FIG. 2 is a perspective view of the main parts of an embodiment of the moving electromagnetic coil 11 and the fixed electromagnetic coils 12 to 15, including a cylindrical permanent magnet 21 with N and S poles appearing at the top and bottom, Coil 22 wound around this
It is composed of Fixed side electromagnetic coil 12
- 15, the cylindrical permanent magnet 21 is fixed at a predetermined position using a suitable fixture so that, for example, the N pole faces the magnetostrictive metal plate 10 at an appropriate distance as required, and the moving side In the case of the electromagnetic coil 11, for example, the N pole of the cylindrical permanent magnet 21 is placed in a housing (cursor body) that slides on the surface of the magnetostrictive metal plate 10, and is separated from the magnetostrictive metal plate 10 by an appropriate distance as necessary. They are stored facing each other.

FIG. 3 illustrates the state of the magnetic field generated by the cylindrical permanent magnet 21 of FIG. 2.
When the poles are opposed to the magnetostrictive metal plate 10, the region of the magnetostrictive metal plate 10 immediately below the north pole is magnetized in a radial direction toward a point opposite to the center of the magnetic pole.

Figure 4 shows the state of magnetization of the cylindrical permanent magnet 21.
This is a diagram viewed from above on the side where is placed, and the arrow indicates the direction of magnetization, from the north pole to the south pole. Such magnetization is erased when the cylindrical permanent magnet 21 is removed, and when the cylindrical permanent magnet 21 is moved to another point on the magnetostrictive metal plate 10, magnetization in the same direction as that shown in FIG. 4 occurs there. For this reason, when using an electromagnetic coil as a magnetostrictive pulse detector, it is possible to convert magnetostrictive waves into electrical signal pulses (induced voltage) with almost constant strength no matter what direction the magnetostrictive waves arrive. Furthermore, even when an electromagnetic coil is used as a magnetostrictive pulse generator, magnetostrictive waves can be strongly generated at all angles, that is, in the radial direction.

FIG. 5 is a block diagram of an embodiment of the processing apparatus used in combination with the apparatus portions shown in FIG. In the figure, a pulse generator 30 is an oscillator that periodically generates trigger pulses, and its output pulses are amplified by an amplifier 31 and applied to the moving electromagnetic coil 11 in FIG. 1 via a signal line 16. The output of the pulse generator 30 is also connected to a counter circuit 32.
It is applied as a reset signal to gate circuits 34 to 37 as a timing signal for opening the gates.

The counter circuit 32 includes a reference clock generator 33.
The counter circuit 32 starts counting the reference clock from the initial value when it is reset. The count value of this counter circuit 32 is input to gate circuits 34-37.

On the other hand, the fixed electromagnetic coils 12 to 15 in FIG. When the induced voltage (magnetostrictive wave pulse) is detected, the output of the magnetostrictive pulse detection circuits 38 to 41 becomes, for example, "1". The outputs of the magnetostrictive pulse detection circuits 38-41 are applied to the gate circuits 34-37 as timing signals for closing the gates.

The gate circuits 34 to 37 open their gates in response to pulses from the pulse generator 30 to open the gates of the counter circuit 3.
Buffer circuits 42 to 4 corresponding to the count value of 2
5 and the corresponding magnetostrictive pulse detection circuit 38~
When the output of 41 becomes "1", the gate is closed. Therefore, the final values of the buffer circuits 42 to 45 indicate the count values to the counter circuit 32 at the time when the magnetostrictive pulses are detected by the corresponding magnetostrictive pulse detection circuits 38 to 41. The contents of the buffer circuits 42 to 45 are connected to a personal computer 50 via signal lines 46 to 49, and the personal computer 50 controls the moving side electromagnetic coil 11 based on the values of the buffer circuits 42 to 45.
Calculate the position of.

Next, the operation of this embodiment will be explained with reference to each figure.

Now, on the magnetostrictive metal plate 1, the XY
Assuming a coordinate system, the fixed side electromagnetic coil 1 is placed at the coordinate origin.
3, the fixed electromagnetic coil 14 is placed at a certain point on the X axis, the fixed electromagnetic coil 12 is placed at a certain point on the Y axis, and the fixed electromagnetic coil 15 is placed in the first quadrant. Suppose that it is placed.

When the moving side electromagnetic coil 11 is moved and placed at the coordinate (x, y) point on the magnetostrictive metal plate 10, when a pulse is generated from the pulse generator 30 in FIG. The moving side electromagnetic coil 11 is excited by the output pulse, and an instantaneous magnetostrictive wave is generated at the coordinate (x, y) point of the magnetostrictive metal plate 10, and this instantaneous magnetostrictive wave is radiated around the point (x, y). It propagates in the direction. On the other hand, when a pulse is output from the pulse generator 30, the counter circuit 32 starts counting the reference clock, and the gate circuits 34 to 37 are opened.

If the above instantaneous magnetostrictive wave propagates through the magnetostrictive metal plate 10 and first reaches the fixed electromagnetic coil 15, the output of the magnetostrictive pulse detection circuit 41 becomes "1" and the gate circuit 37 closes. The buffer circuit 45 stores and holds the number of reference clocks required for the instantaneous magnetostrictive wave to propagate the distance from the point (x, y) to the fixed electromagnetic coil 15. Similarly, when the instantaneous magnetostrictive waves reach the other fixed electromagnetic coils 12 to 14, the magnetostrictive pulse detection circuits 38, 39, 4
The output of 0 becomes “1” and the gate circuits 34, 3
5, 36 are closed, buffer circuits 42, 43, 44
The number of reference clocks required for the instantaneous magnetostrictive wave to propagate the distance from the point (x, y) to the fixed electromagnetic coils 12, 13, 14 is stored and held in each of the fields. 4 stored in these buffer circuits
The reference clock number is 5 for personal computers.
0 and its arithmetic function calculates the point (x,
y) coordinate values are calculated.

Various methods can be adopted as the method for calculating the coordinate values by the personal computer 50, and the present invention is not limited to these methods. In principle, the coordinate values can be calculated from the reference clock numbers of the two buffer circuits, so
Although coordinate values may be determined by selecting two reference clock numbers from among the four reference clock numbers stored in the buffer circuits 42 to 45, in this embodiment, a set of two different reference clock numbers is used. In this case, there can be a maximum of six sets, so in order to improve accuracy, the coordinate values obtained for all or a plurality of sets may be averaged. In the above explanation, the XY coordinates were set on the magnetostrictive metal plate 10 as shown in FIG. As long as the relationship with the mounting position is determined in advance, the coordinates can be set freely.

In particular, according to this embodiment, the moving side electromagnetic coil 11
is used for generating magnetostrictive waves, and the instantaneous magnetostrictive waves generated here are commonly detected by multiple fixed-side electromagnetic coils, so the fixed-side electromagnetic coil is used for generating magnetostrictive waves and sequentially generates instantaneous magnetostrictive waves. This has the effect that the position detection time is shorter than that of the embodiment described later. Further, in principle, it is sufficient to provide only two fixed-side electromagnetic coils, and the configuration can be simplified.

FIG. 6 is a block diagram of a processing apparatus according to another embodiment of the present invention, and the same reference numerals as in FIG. 5 indicate the same parts. The difference between this embodiment and the embodiment shown in FIG. 5 is that the counter circuit 32 is reset by the output of the pulse generator 30 in FIG. The point is that the counter 32 is configured to be reset at the timing when the first magnetostrictive pulse is detected.

In FIG. 6, flip-flops 53 to 57
is initially reset and the output Q is "0", the counter circuit 32 maintains the reset state, and the gate circuits 34 to 37 are closed. Pulse generator 30
When a pulse is output from and the moving side electromagnetic coil 11 in FIG. 1 is excited by the output of the amplifier 31,
As described above, instantaneous magnetostrictive waves are generated and propagate through the magnetostrictive metal plate 10.

For example, when the instantaneous magnetostrictive wave first reaches the fixed side electromagnetic coil 15, the output of the magnetostrictive pulse detection circuit 41 becomes "1", and is applied to the set terminal S of the flip-flop 53 via the OR circuit 51 and the AND circuit 52. "1" is added, and the output Q of the flip-flop 53 becomes "1". As a result, the reset state of the counter circuit 32 is released, the counting of the reference clock is started, and the gate circuits 34 to 34 are reset.
36 will be held. Note that the gate circuit 37 remains closed due to the output of the magnetostrictive pulse detection circuit 41. Also, at this time, the flip-flop 54 is set by the output of the magnetostrictive pulse detection circuit 41.

With the propagation of the instantaneous magnetostrictive wave, when magnetostrictive pulses are detected in the other fixed side electromagnetic coils 12 to 14,
The gate circuits 34 to 36 are closed by each output, and the instantaneous magnetostrictive waves generated in the buffer circuits 42 to 44 reach each of the fixed electromagnetic coils 12 to 14 from the moment the generated instantaneous magnetostrictive waves reach the fixed electromagnetic coil 15. The number of reference clocks required to reach this point remains stored. The personal computer 50 is
The contents of the buffer circuits 42 to 45 are checked, and the position where the moving side electromagnetic coil 11 is placed is calculated based on the reference clock numbers stored in the other three buffer circuits excluding the buffer circuit whose value is "0". .
In this case, the distance between the moving electromagnetic coil 11 and each of the fixed electromagnetic coils 12 to 15 cannot be directly obtained, but the distance between the fixed electromagnetic coil where the magnetostrictive wave was first detected and the moving electromagnetic coil, Since the difference in distance between the fixed electromagnetic coil and the moving electromagnetic coil can be obtained, the position of the moving electromagnetic coil 11 can be determined by simple calculation.

In FIG. 6, when all the magnetostrictive pulse detection circuits 38 to 41 detect magnetostrictive pulses, the flip-flops 54 to 57 are all set, and the output of the AND circuit 58 resets the flip-flop 53 to return to the initial state. However, flip-flops 54-57 are also reset again.

As described above, according to this embodiment, as is clear from FIG. 6, the pulse generator 30 can be separated from other processing units, and the housing ( This has the advantage that the cursor body can be made wireless.

FIG. 7 is a block diagram of a processing device in still another embodiment of the present invention, in which the same reference numerals as in FIG. 5 indicate the same parts, 60 is a quaternary counter, 61 to 64
is a gate circuit, and 65 to 68 are signal lines 17, respectively.
~20 to the fixed side electromagnetic coil 12~ in FIG.
15 is an amplifier, 69 and 71 are selectors, and 70 is a magnetostrictive pulse detection circuit connected to the moving side electromagnetic coil 11 in FIG.

This embodiment is based on the fixed electromagnetic coil 12 shown in FIG.
~15 is used for generating magnetostrictive waves, and moving side electromagnetic coil 1
1 is used for detecting magnetostrictive waves.

In FIG. 7, when the first pulse is generated from the pulse generator 30, the output of the quaternary counter 60 is
G1 becomes "1", the gate circuit 61 is opened, the pulse from the pulse generator 30 is amplified by the amplifier 65, the fixed electromagnetic coil 12 shown in FIG. It is generated in the opposing portions of the magnetostrictive metal plates 10. Further, the output pulse of the pulse generator 30 causes the counter circuit 3 to
2 is reset and counting of the reference clock is started, and the output G1 of the quaternary counter 60 becomes "1", so that the output of the selector 69 is switched to the gate circuit 34 side, the gate circuit 34 is opened, and the selector 71 is switched to the gate circuit 34 side. The output of is also switched to the gate circuit 34 side. As a result, the counter value of the counter circuit 32 is always input to the buffer circuit 42. When the generated instantaneous magnetostrictive wave propagates through the magnetostrictive metal plate 10 and reaches the moving electromagnetic coil 11 placed at a certain position, the output of the magnetostrictive pulse detection circuit 70 becomes "1".
The gate circuit 34 is closed by the output of the magnetostrictive pulse detection circuit 70 via the selector 71, and the buffer circuit 42 closes the fixed side electromagnetic coil 12.
The reference clock number from the time when the instantaneous magnetostrictive wave is generated to the time when it reaches the moving electromagnetic coil 11 is held.

When a pulse is generated again from the pulse generator 30 after a predetermined period of time has elapsed, the output G2 of the quaternary counter 60 becomes "1", so the gate circuit 35,
62 is opened, and selectors 69 and 71 are switched to the gate circuit 35 side. Therefore, the fixed side electromagnetic coil 13 is now excited by the output of the amplifier circuit 66. Then, the counter circuit 32 is reset and starts counting the reference clock again from the initial value, and when a magnetostrictive pulse is detected in the moving side electromagnetic coil 11, the gate circuit 35 is closed by the output of the selector 71, and the buffer circuit 43 is The reference clock number from the time when the instantaneous magnetostrictive wave is generated in the fixed electromagnetic coil 13 to the time when it reaches the moving electromagnetic coil 11 is held.

Similarly, the output G3 of the quaternary counter 60 becomes "1" by the next pulse of the pulse generator 30, and the fixed side electromagnetic coil 14 is excited by the output of the amplifier circuit 67, and is fixed to the buffer circuit 44. The reference clock number from the time when the instantaneous magnetostrictive wave is generated by the side electromagnetic coil 14 to the time when the magnetostrictive pulse is detected by the moving side electromagnetic coil 11 is stored, and the next pulse from the pulse generator 30 is used to generate a quaternary counter. 60 becomes "1" and the fixed side electromagnetic coil 15 is excited, and from the time when an instantaneous magnetostrictive wave is generated in the fixed side electromagnetic coil 15 to the time when a magnetostrictive pulse is detected in the moving side electromagnetic coil 11. The reference clock number is stored in the buffer circuit 45.

The personal computer 50 has a buffer circuit 4
When the measured reference clock numbers 2 to 45 are all stored, the position of the moving side electromagnetic coil 11 is calculated based on the values in the same manner as in the embodiment shown in FIG. In this embodiment as well, position detection is possible as long as there are at least two fixed-side electromagnetic coils.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various other additions and changes are possible. For example, the permanent magnet used in the electromagnetic coil may be a cylindrical permanent magnet, a ring-shaped permanent magnet, or the like other than a cylindrical permanent magnet.

〔Effect of the invention〕

As explained above, the present invention generates instantaneous magnetostrictive waves or detects magnetostrictive pulses by arranging an electromagnetic coil having a permanent magnet as its magnetic core to face a magnetostrictive metal plate. Since the area to be detected or the area to be detected is magnetized almost radially, there is no need to magnetize the magnetostrictive metal plate itself in advance, and even if the magnetostrictive metal plate is magnetized by an external magnetic field, it will not be affected by it. It is possible to generate a sufficiently large induced voltage in the electromagnetic coil, which has the effect of enabling accurate position detection. Therefore, it is very effective to apply the position detection device of the present invention to input devices such as personal computers, position detection devices for moving objects, and the like.

[Brief explanation of drawings]

Fig. 1 is a plan view of essential parts of an embodiment of the present invention, Fig.
The figure shows a moving electromagnetic coil 11 and a fixed electromagnetic coil 1.
3 is a diagram showing the state of the magnetic field generated by the cylindrical permanent magnet 21 of FIG. 2, and FIG.
FIG. 5 is a block diagram of an embodiment of a processing device used in combination with the device shown in FIG. 1, and FIG. FIG. 7 is a block diagram of a processing device according to another embodiment of the invention, FIG. 8 is an explanatory diagram of a conventional position detection device, and FIG. It is an explanatory diagram of a conventional problem. In the figure, 10 is a magnetostrictive metal plate, 11 is a moving side electromagnetic coil, 12 to 15 are fixed side electromagnetic coils, and 3
0 is a pulse generator, 31 is an amplifier, 32 is a counter circuit, 33 is a reference clock generator, 34 to 37
1 is a gate circuit, 38 to 41 are magnetostrictive pulse detection circuits, and 42 to 45 are buffer circuits.

Claims (1)

[Scope of Claims] 1. A magnetostrictive metal plate, and a plurality of fixed sides each having a permanent magnet as a magnetic core, which is attached near an end of the magnetostrictive metal plate and magnetizes a region of the magnetostrictive metal plate at the attachment position substantially radially. an electromagnetic coil; a moving side electromagnetic coil having as a magnetic core a permanent magnet that can be moved to any position on the surface of the magnetostrictive metal plate and magnetizes the area of the magnetostrictive metal plate at the moved position substantially radially; an electric pulse applying means for applying an electric pulse to the electromagnetic coil; and an electric pulse applying means provided in one-to-one correspondence with the plurality of fixed-side electromagnetic coils, the electric pulse being applied by the electric pulse applying means to generate an electric pulse on the magnetostrictive metal plate. a plurality of magnetostrictive pulse detection means for detecting an induced voltage generated in a corresponding fixed-side electromagnetic coil by a magnetostrictive oscillation wave; and a plurality of magnetostriction pulse detection means each detecting the induced voltage at each time point and the above. a time measuring means for determining the respective time differences from the time points at which the electric pulses are applied; and a calculation for calculating the position of the moving side electromagnetic coil on the magnetostrictive metal plate based on the respective time differences determined by the time measuring means. A position detection device characterized by comprising means. 2. a magnetostrictive metal plate; a plurality of fixed-side electromagnetic coils each having as a magnetic core a permanent magnet that is attached near an end of the magnetostrictive metal plate and magnetizes the area of the magnetostrictive metal plate at the attachment position substantially radially; a moving-side electromagnetic coil having as a magnetic core a permanent magnet that can be moved to any position on the surface of the metal plate and magnetizes the magnetostrictive metal plate region at the moved position substantially radially; and an electric pulse is applied to the moving-side electromagnetic coil. An electric pulse applying means is provided in one-to-one correspondence with the plurality of fixed side electromagnetic coils, and magnetostrictive vibration waves are generated in the magnetostrictive metal plate by the electric pulses applied by the electric pulse applying means. a plurality of magnetostrictive pulse detection means for detecting an induced voltage generated in a corresponding fixed-side electromagnetic coil; and a time point at which an induced voltage is first detected in the plurality of magnetostriction pulse detection means after the electric pulse is applied, and thereafter. a time measuring means for determining the respective time differences from respective points in time when the induced voltage is detected; and determining the position of the moving side electromagnetic coil on the magnetostrictive metal plate based on the respective time differences determined by the time measuring means. 1. A position detection device comprising: calculation means for calculating. 3. a magnetostrictive metal plate; a plurality of fixed-side electromagnetic coils each having as a magnetic core a permanent magnet that is attached near an end of the magnetostrictive metal plate and magnetizes the area of the magnetostrictive metal plate at the attachment position substantially radially; a movable electromagnetic coil having as a magnetic core a permanent magnet that can be moved to any position on the surface of the metal plate and magnetizes the area of the magnetostrictive metal plate at the moved position substantially radially; and the plurality of fixed electromagnetic coils. an electric pulse applying means for sequentially applying electric pulses; and an induced voltage sequentially generated in the moving side electromagnetic coil by magnetostrictive vibration waves sequentially generated in the magnetostrictive metal plate by the electric pulses sequentially applied by the electric pulse applying means. magnetostrictive pulse detection means for detecting; and determining a time difference between each time point when an electric pulse is applied to each of the plurality of fixed side electromagnetic coils and the time point when an induced voltage is detected by the magnetostriction pulse detection means. A position detection device characterized by comprising: a time measurement means; and a calculation means for calculating the position of the moving side electromagnetic coil on the magnetostrictive metal plate based on the respective time differences determined by the time measurement means. .