JPS6136823A - Position detector - Google Patents

Abstract

PURPOSE:To attain an input action with high operability without setting any code, etc. by putting a pad containing a pressure-sensitive rubber sheet held between upper and lower electrodes on a position detecting surface and detecting the timing when a contact is obtained between said rubber sheet and a generator of magnetism for position designation. CONSTITUTION:A pressure-sensitive rubber sheet 12 has the resistance of several hundreds of KOMEGA/mm.<2> with no pressure applied and then several tens of OMEGA/mm.<2> when the pressure is applied. No current is virtually flowed between upper and lower electrodes 11 and 13 as long as no pressure is applied to the electrode 11 of a pad 10 from a generator of magnetism for position designation. Then the voltage of a DC power supply E emerges as it is at the input of a multivibrator 21, and the multivibrator 21 has no actuation. While said magnetism generator has a light contact with either area on the electrode 11. Thus a current flows between both electrodes 11 and 13 at the contact area of the magnetism generator. Then the voltage of the input terminal of the vibrator 21 is equal to an earth potential, and the vibrator 21 delivers a prescribed one-shot pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a position detection device that detects a position designated by a position designation magnetic generator that generates a steady magnetic field. The present invention relates to a device with improved operability.

(Prior Art) FIG. 8 shows an example of a conventional position detection device of this type, which includes a long magnetostrictive transmission medium 1 and a seventh coil 2 disposed around one end of the magnetostrictive transmission medium 1. , a second coil 3 disposed around a wide area of the magnetostrictive transmission medium 1, a pulse current generator 4, a processing device 5, and a position specifying magnetic generator 1 that generates a steady magnetic field, such as a rod. It consists of a magnet 6 and a bias magnetic body 7.

In such a configuration, the pulse current generator 4
When a pulse current is applied to the coil 2, an instantaneous magnetic field fluctuation occurs in the first coil 2, thereby generating a magnetostrictive oscillatory wave in the area where the M1 coil 2 of the magnetostrictive transmission medium 1 is wound. This magnetostrictive vibration wave propagates along the longitudinal direction at a propagation speed unique to the magnetostrictive transmission medium 1, but during this propagation, the electromechanical coupling coefficient of that part increases at a portion of the magnetostrictive transmission medium 1 where the magnetostriction vibration wave exists. Accordingly, the mechanical energy is converted into magnetic energy, and an induced electromotive force is generated in the second coil 3.

Here, when a certain part of the magnetostrictive transmission medium 1 is designated by the position designating magnetic generator 6 and magnetism is applied to that part to an extent that increases the electromechanical coupling coefficient, #magnetostrictive vibration waves are generated at that part. When the 8th position is reached, a large induced electromotive force is generated in the second coil 3.

Therefore, during the time from the time when a pulse current is applied to the first coil 2 to the time when this large induced electromotive force is generated, the magnetostrictive vibration wave moves from the position where the first coil 2 of the magnetostrictive transmission medium 1 is provided to the position specifying magnet. It is equal to the time required to reach the position specified by the generator 6. Therefore, by detecting this time by the processing device 5 and multiplying it by the speed of the magnetostrictive vibration wave, the distance J between the position specifying magnetic generator 6 and the first coil 2, that is, the position specifying magnetic generator 6 coordinate values can be detected.

A position detecting device in which a plurality of position detecting elements each consisting of the magnetostrictive transmission medium 1, the first coil 2, and the second coil 3 as described above are arranged in parallel and is combined in the X and Y directions has already been put into practical use. There is.

(Problems to be Solved by the Invention) In the case of the position detection device, a pulse current is applied to the first coil 2 only when a predetermined timing signal is applied, and the coordinate values detected at this time are extracted. You can also,
A pulse current is applied to the first coil 2 at a certain period in advance, and when the position specifying magnetic generator 6 is placed at the 8 mark position to be input, a predetermined timing signal is given to determine the coordinates detected at that time. It is also possible to extract only the value, but in either case a timing signal is required. The switch means for generating this timing signal was often provided in the position specifying magnetic generator 6, but when only the switch means is provided in the position specifying magnetic generator 6, a cord is required between the position specifying magnetic generator 6 and the processing device. In addition, in order to make it cordless, if ultrasonic waves or infrared rays are used to transmit information to the processing location, the transmitter, signal generation circuit, battery, etc. must be attached to the position specifying magnetic generator 6, which is large and heavy. In either case, it is difficult to avoid deterioration in the operability of specifying a position.

It is an object of the present invention to solve these conventional drawbacks and to realize a position detecting device for a position specifying magnetic generator with good operability.

(Means for Solving the Problems) FIG. 1 shows the main parts of the present invention, in which 10 is a pressure-sensitive pad, 20 is a timing detection circuit that detects the timing when the magnetic generator comes into contact with the pad 1. It is.

The band 10 consists of a thin copper foil 1 on a flexible substrate 11a.
It consists of an upper electrode 11 with a thin copper foil 13b pasted on it, a pressure-sensitive rubber sheet 12 whose resistance value decreases when pressure is applied, and a lower electrode 13 with a thin copper foil 13b pasted on an insulating substrate 13a. A pressure sensitive rubber sheet 12 is inserted between the lower electrode 13 and the lower electrode 13. The timing detection circuit 20 consists of a +5 volt (high level) DC power supply E and a one-shot multivibrator 21.
The one-shot multivibrator 21 has an input voltage ranging from a high level (+5 volts) to a low level (O volts).
When the voltage changes to , a predetermined one-shot pulse is output.

The DC power source E is connected to the input terminals of the upper electrode 11 and the one-shot multivibrator 21, and is also connected to the lower electrode 1.
3 is grounded.

(Function) The resistance of the pressure-sensitive rubber sheet 12 is several hundred Ω/l1m2 when no pressure is applied, but it decreases to several tens of Ω when pressure is applied.
/1II12. Therefore, in the pad 10, if pressure is not applied to the upper electrode 11 by the position specifying magnetic generator, almost no current will flow between the upper electrode 11 and the lower electrode 13, and the multivibrator 210 input terminal The voltage of the DC power source E appears as is, and the multivibrator 21 does not operate. On the other hand, when the position specifying magnetic generator is lightly pressed on any part of the upper electrode 11, a current flows between the upper electrode 11 and the lower electrode 13 at that part, and the voltage at the input terminal of the multi-vibration break 21 is becomes the ground potential, that is, O volts (low level), and the multivibrator 21 outputs a predetermined one-shot pulse.

Therefore, if the pad 10 is placed on the position detection surface of the position detection device and the output of the timing detection circuit 20 is sent to the processing device, a cord can be attached to the magnetic generator for position designation, or an ultrasonic wave or Timing signals can be extracted without providing an infrared transmitter, a signal generation circuit, a battery, etc., and input operations with good operability are possible.

(Embodiment) FIGS. 2 to 7 show an embodiment of the present invention, and here, an example in which the present invention is applied to a position detection device using magnetostrictive vibration waves is shown. In the figure, 30 is a tablet, 40 is a position detection circuit, and 50 is a position designating magnetic generator. The pad 10
has an input range approximately the same area as the coordinate input range of the tablet 30, and is placed on its position detection surface. The timing detection circuit 20 sends a timing signal to the position detection circuit 40. Then, operate the magnetic generator 50 for position designation on the pad 10, and press the magnetic generator 50 at the position to be input.
By pressing the button on the band 10, the coordinates can be input.

Next, the structure and operation of each part will be explained in detail with reference to the drawings.

FIG. 3 is a plan view showing the structure of the tablet 30, and FIG. 4 is a sectional view taken along the line AA' in FIG.

In the figure, 31 is a magnetostrictive transmission medium in the X direction, and 32 is a Y direction magnetostrictive transmission medium.
A plurality of magnetostrictive transmission media are arranged substantially parallel to each other. Any ferromagnetic material can be used as the magnetostrictive transmission medium 31, 32, but a material with a large magnetostrictive effect, such as an amorphous alloy containing a large amount of iron, is particularly desirable in order to generate strong magnetostrictive vibration waves. Further, it is preferable to use a material with a small coercive force that is difficult to magnetize even when a magnet is brought close to the material. Examples of amorphous alloys include Fe 67CO1sB 14
s I 1 (atomic %), Fe81B13.58
1 3.502 (atomic %) etc. can be used. The magnetostrictive transmission medium 31, 32 has an elongated shape, and its cross section is preferably a rectangular thin strip or a circular linear shape, and in the case of a thin strip, the width is about several mats and the thickness is about several μm to several tens of μm. It is easy to use and has good properties. Because amorphous alloys can be made as thin as 20-50 μm,
This may be cut into thin plate shapes or linear shapes.

In this example, Fe81B13.58' 3.502(
A magnetostrictive transmission medium having a width of 2 mm and a thickness of 0.02 ma+ is used.

Reference numerals 33 and 34 denote elongated cylindrical reinforcing members made of synthetic resin or the like, each of which accommodates the magnetostrictive transmission medium 31 and 32 therein.

35 is a first coil in the X direction disposed on the reinforcing member 33 at one end of the magnetostrictive transmission medium 31. This X-direction first coil 3
5 is twisted between adjacent reinforcing members 33 and wound in opposite directions for each adjacent magnetostrictive transmission medium 31, so that when a current is applied to the coil 35, a portion corresponding to each magnetostrictive transmission medium 31 is twisted. The magnetic flux generated by the coil 35 or the voltage generated in each part when a magnetic flux in one direction is applied to the coil 35 is in the opposite direction.For this reason, the pulse generated when a pulse current is passed through the coil 35 Noise and external induction cancel each other between adjacent parts of the coil 35 and are weakened.The number of windings is one in the illustrated example, but it may be 2 or more. 1st coil 3
5 is for generating instantaneous magnetic field fluctuations to generate magnetostrictive vibration waves in each winding portion of the magnetostrictive transmission medium 31;
One end of the coil 35 is connected to a pulse current generator of a position detection circuit 40 described later, and the other end is grounded.

Further, 36 is a first coil in the Y direction disposed on the reinforcing member 34 at one end of the magnetostrictive transmission medium 32, and the adjacent reinforcing member 3
The magnetostrictive transmission medium 32 is twisted between two adjacent magnetostrictive transmission media 32 and wound in opposite directions.

One end of this Y-direction first coil 36 is connected to a pulse current generator like the coil 35, and the other end is grounded.

Note that the action is similar to that of the coil 35.

Reference numerals 37 and 38 are magnetic generators for specifying reference positions, for example square magnets, which are connected to the winding portion of the first coil 35 in the X direction of the magnetostrictive transmission medium 31 and the first coil 36 in the Y direction of the magnetostrictive transmission medium 32.
This is to apply a bias magnetic field parallel to the longitudinal direction to each winding portion of the coil. The reason for applying the bias magnetic field in this manner is to enable the generation of large magnetostrictive vibration waves with a small amount of current, and to specify the generation position of the magnetostrictive vibration waves. That is, the electromechanical coupling coefficient (coefficient of conversion efficiency from mechanical energy to electrical energy or from electrical energy to mechanical energy) of the magnetostrictive transmission medium 31, 32 is determined by a certain bias magnetic field as shown in FIG. 5, for example. Since this is the maximum, such a magnetic bias is
Direction first coil 35. By applying the voltage to the wound portion of the first coil 36 in the Y direction, it is possible to generate magnetostrictive vibration waves with high efficiency.

39 is a reinforcing material 3 over a wide range of the magnetostrictive transmission medium 31.
This is the second coil in the X direction disposed on the top of the second coil. The coil 3
The coils 9 are all wound in the same direction (left-handed in this embodiment) on each magnetostrictive transmission medium 31, and are connected in series such that adjacent coils have opposite connection polarities. Therefore, when magnetic flux in one direction is applied to all coils 39, the voltage, current direction, or coil that occurs in each coil 39.

When a current is passed through the entire coil 39, the direction of magnetic flux generated in each coil 39 is opposite between adjacent coils, and external induction and noise cancel each other between adjacent coils and are weakened.

The winding pitch of the coil 39 is such that it is wound gradually more densely from one end on the side close to the first coil 35 in the X direction toward the other end on the opposite side, and the induced voltage is small due to the attenuation of the magnetostrictive vibration waves. It makes up for becoming. Generally, in order to reduce the induced electromotive force, it is preferable to have a larger winding pitch. This X
The second coil 39 is for detecting the induced voltage due to the magnetostrictive vibration wave propagating through the magnetostrictive transmission medium 31, and one end is connected to the pulse detector of the position detection circuit 40, and the other end is grounded. The wound area becomes a position detection area.

Further, 310 is a Y-direction second coil disposed on the reinforcing member 34 over a wide range of the magnetostrictive transmission medium 32, and the coil 310 is arranged on each magnetostrictive transmission medium 32 in the same direction (
In this embodiment, the coils are wound in a left-handed manner, and are connected in series such that adjacent coils have opposite polarities. Moreover, the winding pitch of this coil 310 is the first in the Y direction.
It is wound gradually more densely from one end close to the coil 34 to the other end on the opposite side, one end of which is connected to a pulse detector like the coil 39, and the other end is grounded. has been done. Note that the action is similar to that of the coil 39.

The above-mentioned
The direction position detecting section is inserted into a recess provided in the inner bottom surface of the non-magnetic metal case 311, and is inserted into a recess provided in the inner bottom surface of the non-magnetic metal case 311, and also detects the direction from the magnetostrictive transmission medium 32, the reinforcing material 34, the first coil 36 in the Y direction, the second coil 310 in the Y direction, etc. The Y-direction position detecting section is superimposed orthogonally on the X-direction position detecting section, and is fixed with an adhesive or the like as necessary. Further, the reference position specifying angle magnets 37.38 are fixed to the inner bottom surface of the metal case 311 so as to face the ends of the magnetostrictive transmission medium 31.32, They may be arranged in parallel in either direction. The top of the metal case 311 is covered with a lid 312 made of non-magnetic metal.

Magnetic generator for position designation (hereinafter referred to as position indicator)>5
0 is, for example, a pen-shaped container with a small bar magnet implanted at the tip with its north pole facing down, and preferably has a cap attached to the tip to prevent damage to the pad 10.

FIG. 6 is a circuit block diagram showing a depiction of the position detection circuit 4o. Coordinate input operations using the tablet 30, position detection circuit 40, and position indicator 50 will be described in detail below.

Now, the position indicator 50 is connected to the tablet 3 via the pad 10.
0 on the magnetostrictive transmission medium 31 at a distance of 11 in the X-axis direction from the coil surface center of the first coil 35 in the X direction, and a distance of 12 in the Y-axis direction from the coil surface center of the first coil 36 in the Y direction. Pi!, which is on the medium 32 and has a large electromechanical coupling coefficient. It is assumed that a magnetism of i is applied to the magnetostrictive transmission media 31 and 32.

(However, it is assumed that the pad 10 is not pressed to the extent that it becomes conductive.) When the power switch (not shown) of the position detection circuit 40 is turned on, the control circuit 41 controls the counter 43 via the output ballast 42. During reset, the Xh direction pulse current generator 44 is operated. The counter 43 starts counting the clock pulses (pulse repetition frequency is, for example, 100M)-1z) of the clock generator 45.

The pulse current generator 44 for the Xh direction operates and the pulse current is
When the magnetic field is applied to the first coil 35 in the X direction, an instantaneous magnetic field fluctuation occurs in the first coil 35 in the X direction, and this causes a magnetostrictive vibration wave to be generated in the wound portion of the first coil 35 in the X direction of the magnetostrictive transmission medium 31. Zuru. This magnetostrictive vibration wave propagates along the longitudinal direction of the magnetostrictive transmission medium 31 at a propagation speed (approximately 5000 m/sec) specific to the magnetostrictive transmission medium 31. And during this propagation, J5
Then, at a portion of the magnetostrictive transmission medium 31 where the magnetostrictive vibration waves exist, mechanical energy is converted into magnetic energy according to the magnitude of the electromechanical coupling coefficient at that portion. An induced electromotive force is generated.

FIG. 7 shows an example of the temporal change in the induced electromotive force generated in the second coil 39 in the X direction, with the time when the pulse current is applied to the first coil 35 in the X direction being 1=0. As shown in the figure, the amplitude of the induced electromotive force increases immediately after time 1=0 and around 11 to 12 seconds after time 10, and decreases at other times. Immediately after time 1=0, the amplitude of the induced electromotive force becomes large because the first coil 35 in the X direction and the
This is due to the electromagnetic induction effect between the second coils 39 in the X direction, and the reason why the amplitude of one cycle of induced electromotive force (induced voltage due to magnetostrictive oscillation waves) becomes large at time 1=11 to 12 is due to the electromagnetic induction effect between the first coils 35 in the X direction. This is because the magnetostrictive vibration waves generated in the winding portion propagate through the magnetostrictive transmission medium 31 and reach the vicinity directly below the position indicator 50, and the electromechanical coupling coefficient becomes large at that portion. When the position indicator 50 is moved along the longitudinal direction X of the magnetostrictive transmission medium, the voltage induced by the magnetostrictive vibration waves also moves on the time axis accordingly.

Therefore, by measuring the time from time t to t1 to t2, the position in the X direction specified by the position indicator 50,
That is, the distance 1IllI11 can be calculated. As the propagation time for calculating the position, for example, as shown in FIG. 7, the time point t3 when the amplitude of the induced voltage due to magnetostrictive vibration becomes smaller than the threshold value -El, the threshold value E, and the time point t4 when it becomes larger are used. Alternatively, the zero cross point t5 may be used.

The induced electromotive force generated in the X-direction second coil 39 described above is input to the X-direction pulse detector 46. The X-direction pulse detector 46 is composed of an amplifier, a comparator, etc., and outputs its output while the induced electromotive force is greater than, for example, the aforementioned threshold value E1, that is, when it detects the positive polarity portion of the induced voltage due to the magnetostrictive vibration wave. High level. When the control circuit 41 reads this high level signal via the input buffer 747,
A stop signal is output to the counter 43 via the output buffer 42 to stop counting. At this time, the counter 43 obtains a digital value corresponding to the time from the time when the pulse current is applied to the first coil 35 in the X direction until the induced voltage due to the magnetostrictive vibration wave appears in the second coil 39 in the X direction. Further, this value corresponds to the distance l1lIt11 in the X direction from the first coil 35 in the X direction to the position indicator 50 because the magnetostrictive vibration wave travels at a speed of 5000 m per second. The X-direction position data obtained in the counter 43 as digital 1st shift in this way is transferred to the input buffer 4.
7 to the control circuit 41.

Then, the control circuit 41 resets the counter 43 again and returns Y.
The direction pulse current generator 48 is operated, the output of the Y direction pulse detector 49 is monitored, and the Y direction position data of the position indicator 50 is obtained in the same manner as described above. Thereafter, this is repeated at a predetermined period. By moving the position indicator 50, position data indicated one after another can be obtained.

In this state, the position indicator 50 is placed on the pad 10.
When pressed lightly, a timing signal is sent from the timing detection circuit 20 to the position detection circuit 40. The timing signal is read into the control circuit 41 via the input buffer 747, and the control circuit 41 recognizes the coordinate input and determines the X value at that time.

The Y direction position data is sent to a computer etc. as input coordinate values.

According to the above configuration, the coordinates are not input simply by placing the position indicator 50 on the pad 10 on the tablet, and the coordinates can be input only by pressing lightly, so it feels as natural as using a normal writing instrument. Input operations are now possible. Furthermore, if all the data obtained by the control circuit 41 is sent to an anisotropic device such as a CRT and displayed, the indicated position of the position indicator 50 can be known more accurately, and more accurate coordinate input is possible. .

In the embodiment described above, the X-direction first coil 35. The first coil 36 in the Y direction is used for generating magnetostrictive vibration waves, and the second coil 39 in the X direction is used for generating magnetostrictive vibration waves. Although the second coil 310 in the Y direction is used for detecting magnetostrictive vibration waves, it may be used in the opposite direction. In that case, magnetostrictive vibration waves are generated directly under the position indicator 50, and the second coil 39
, 310, an induced pressure will be generated.

Although the above embodiment was applied to transmission of magnetostrictive vibration waves, it is also possible to use electromagnetic induction of a magnetic material, and the point is to send an instantaneous signal from the position indicator to the tablet side ( Or vice versa), it is fine as long as it is not necessary to give.

(Effects of the Invention) As explained above, according to the present invention, in a position detection device that detects a position designated by a position designation magnetic generator that generates a steady magnetic field, Equipped with a pressure-sensitive pad and a timing detection circuit that detects the timing when the position specifying magnetic generator comes into contact with the pad, it is possible to attach a cord to the position specifying magnetic generator or transmit ultrasonic waves or infrared rays. The timing signal can be extracted without installing a machine, signal generation circuit, battery, etc., and the magnetic generator for position specification can be easily configured, small, and lightweight.
It enables input operations that feel natural and easy to operate, just like using a regular writing instrument. In addition, the timing signal is not generated just by placing the position indicator on the pad, but only when it is lightly pressed 4 times, so the data obtained by the detection device is sent to a display device such as a CRT and displayed. This has the advantage that the indicated position of the position specifying magnetic generator can be known more accurately, and more accurate coordinate input becomes possible.

[Brief explanation of the drawing]

The drawings are for explaining the present invention. FIG. 1 is an explanatory diagram showing the configuration of the main part of the present invention, FIGS. 2 to M7 show an embodiment of the present invention, and FIG. Explanatory diagram showing, 3rd
The figure is a plan view showing the structure of the tablet, and Figure 4 is Figure 3A.
5 is a characteristic diagram of magnetic bias versus electromechanical coupling coefficient, 6 is a block diagram of the position detection circuit, and 7 is an induced electromotive force generated in the second coil in the X direction. FIG. 8 is an explanatory diagram showing an example of a conventional position detection device. 10... Pressure-sensitive pad, 11... Upper electrode, 12
...Pressure sensitive rubber sheet, 13... Lower electrode, 20...
- Timing detection circuit, 21... One-shot multivibrator, E... DC power supply. Patent applicant Wacom Co., Ltd. Patent attorney Furu 1) Takashi SeiFigure 1Figure 2Figure 3Figure 4Figure 5Figure 7

Claims (1)

[Claims] A position detection device that detects a position specified by a position designation magnetic generator that generates a steady magnetic field, includes a pressure-sensitive pad placed on a position detection surface, and a position designation magnetic generator attached to the pad. 1. A position detection device comprising: a timing detection circuit that detects the timing of contact.