JPS6175421A - Position detecting device - Google Patents

Abstract

PURPOSE:To improve the operability of a magnetic generator for position specification and to improve the operability, specially, when handwritten characters and a figure are inputted by fitting an oscillation pickup to an input panel and providing a timing detecting circuit. CONSTITUTION:The oscillation pickup 10 has a piezoelectric element in its flat disc type main body 11 and transduces oscillation transmitted to the main body 11 into an electric signal through piezoelectric effect, and its output signal is outputted to the timing detecting circuit 20 through a lead line 12. The circuit 20 consists of a preamplifier 21, AGC amplifier 22, band-pass filter 23, etc.; the amplifiers 21 and 22 amplify the output signal of the pickup 10 up to a specific level and the filter 23 extracts only a necessary signal from the amplified signal. Namely, only the signal of oscillation generated when the magnetic generator for position specification is moved on the input panel is extracted, so a timing signal corresponding to only the movement period is extracted. Consequently, the operability of the magnetic generator for position specification and the operativity, specially, when handwritten characters and a figure are inputted.

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. 9 shows an example of a conventional position detection device of this type, which includes a long magnetostrictive transmission medium 1 and a first 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 2 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 vibration wave in the area where the first 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, 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, the magnetostrictive vibration waves are transmitted to that part. When it reaches , 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 imaging wave is used for position specification from the position where the first coil 2 of the magnetostrictive transmission medium 1 is provided. It is equal to the time required for the magnetic generator 6 to reach the specified position. Therefore, by detecting this time by the processing device 5 and multiplying it by the speed of the magnetostrictive vibration wave, the distance between the position specifying magnetic generator 6 and the first coil 2 @5, that is, the position specifying magnetic generator 6 coordinate values can be detected.

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

(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 coordinate position to be input, a predetermined timing signal is applied to the coordinate value detected at that time. It is also possible not to take out the only one, but in either case a timing signal is required.

In most cases, this timing signal is generated by providing a switch in the position specifying magnetic generator 6 and generating it based on the on/off state of the switch.
It is necessary to operate a switch, especially when inputting handwritten characters or figures, such as turning it on while drawing the stroke of the character and issuing a timing signal, and turning it off while moving from one stroke to the next stroke. The switch had to be turned on and off frequently in short cycles, and precisely in accordance with the stroke, making it difficult to operate. In addition, in the case where the magnetic generator 6 for position designation is equipped with a switch, in order to transmit on/off of the switch to the processing device 5, a cord is attached to the magnetic generator 6 for position designation, or ultrasonic or infrared rays are used. An oscillation device must be provided, which has disadvantages such as inconvenience in position designation operations and a complicated configuration that increases costs. In addition, it has been proposed that a pressure-sensitive rubber pad or the like is provided on the position detection surface to detect the timing when the position specifying magnetic generator 6 is pressed against the rubber pad at Gj. It has the disadvantage that it cannot be used in cases where a continuous timing signal is required, such as in the case of

It is an object of the present invention to solve these conventional drawbacks and to realize a position detection device with good operability for a magnetic generator for position specification, especially when inputting handwritten characters and figures. be.

(Means for solving the problem) The magnetic generator for position specification is connected to the input panel of the position detection device,
Or, when the input panel is moved in contact with a form placed on it, vibrations of a certain frequency are generated in the input panel.

The frequency of this vibration is determined by the material and structure of the magnetic generator for position specification, the input panel, and the entry form, but in general, vibrations generated by objects that come into contact with the input panel, such as hands, during input operations. It's completely different.

Therefore, by detecting the vibrations caused by the movement of the position specifying magnetic generator among the vibrations generated in the input panel, it is possible to detect the timing that coincides with the period in which the stroke of a character or figure is being drawn.

Therefore, in the present invention, in a position detection device that detects a position specified by a position specifying magnetic generator that generates a steady magnetic field, the vibration pickup 10 is attached to the input panel 312, and the output signal of the vibration pickup 10 is A timing detection circuit 20 is provided that extracts only the signal caused by the vibration generated when the position specifying magnetic generator 50 is moved on the input panel 312.

(Function) According to the above configuration, by simply writing on the input panel 312 using the position specifying magnetic generator 50, the timing when the position specifying magnetic generator 50 is in contact with the input panel 312 and is moving, that is, the position The timing of detection can be extracted, and therefore handwritten characters and figures can be input in the same way as normal writing, making it possible to realize a device with good operability.

(Embodiment) FIGS. 1 to 8 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, 10 is a vibration pickup, 20 is a timing detection circuit, 30 is a tablet, 40 is a position detection circuit, and 50 is a position specifying magnetic generator. Hereinafter, the configuration and operation of each part will be explained in detail with reference to the drawings.

Figure 2 shows the vibration pickup 10 and timing detection circuit 2.
0 details. The vibration pickup 10 is
For example, a piezoelectric element is built into the flat disc-shaped main body 11, and the vibrations transmitted to the main body 11 are converted into electrical signals by the piezoelectric effect.As shown in FIG. It is fixed with an agent etc.

The output signal of the imaging pickup 10 is outputted to a timing detection circuit 20 via a lead wire 12.

The timing detection circuit 20 includes a preamplifier 21 and an AGC
(Auto gain control [1-R) amplifier 22, band pass filter 23, rectifier circuit 24, comparator 2
5, the preamplifier 21 and AGC amplifier 22 amplify the output signal of the imaging pickup 10 to a predetermined level, and the bandpass filter 23 specifies the position of the input panel 312 from the amplified signal. Extracts only the frequency components of imaging that occur when the magnetism generator 50 is moved in contact with the camera, for example, signals around i kl-1z.
The 0 rectifier circuit 24 rectifies and smoothes the output of the bandpass filter 23, and the comparator 25 compares the output signal of the rectifier circuit 24 with a predetermined reference voltage E, and when the output signal is higher than the reference voltage E, a high level signal is output. When the voltage is lower than the reference voltage E, a low level signal is sent to the position detection circuit 40.

This high-level signal becomes a timing signal corresponding to the period during which a stroke of a character or figure is drawn on the input panel 312.

FIG. 3 is a plan view showing the structure of the tablet 3o, and FIG. 4 is a sectional view taken along the line A--A 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 in order to generate strong magnetostrictive vibration waves, a material with a large magnetostrictive effect, such as an amorphous alloy containing a large amount of iron, is particularly desirable. 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 FC6□C018B14Si1
(atomic %>, +”e B 3i 3.5C2
(atomic %) 81 13.5 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 mm and the thickness is several μm.
A thickness of about 10 μm is easy to manufacture and has good characteristics. Since amorphous alloys can be manufactured into thin pieces with a thickness of 20 to 50 μm, they can be cut into board shapes or linear shapes.

In this example, a width of 2 m111. A magnetostrictive transmission medium with a thickness of o and 02IIIll is used.

Reference numerals 33 and 34 are elongated cylindrical reinforcing members made of synthetic resin or the like, each of which houses 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, and when a current is applied to the coil 35, a coil is generated from a portion corresponding to each magnetostrictive transmission medium 31. When a magnetic flux is applied to the coil 35 or a magnetic flux in one direction is applied to the coil 35, the voltage generated in each part is in the opposite direction. Therefore, pulse noise generated when a pulse current is passed through the coil 35 and induction from the outside cancel each other out between adjacent portions of the coil 35 and are weakened. Note that although the number of turns is one in the illustrated example, it may be wound two or more times. This X-direction first coil 35 is for generating instantaneous magnetic field fluctuations to generate magnetostrictive vibration waves in each winding portion of the magnetostrictive transmission medium 31, and one end of the coil 35 is connected to a position detection circuit to be described later. 40 pulse current generator, and the other end is grounded.

Moreover, 36 is a Y-direction 1'l-th coil arranged on the reinforcing material 34 at one end of the magnetostrictive transmission medium 32, and is twisted between the adjacent reinforcing materials 34 and reversed for each adjacent magnetostrictive transmission medium 32. It is wound in the direction.

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 a large magnetostrictive vibration wave with a small amount of current, and to specify the generation position of this magnetostrictive imaging wave. That is, the electromechanical coupling coefficient (coefficient indicating the 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. Since it is maximum when , such a magnetic bias is
Direction first coil 35. Magnetostrictive vibration waves can be efficiently generated by applying the voltage to the winding portion of the first coil 36 in the Y direction.
can be done.

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 coils 39 are all wound in the same direction (left-handed in this embodiment) on each magnetostrictive transmission medium 31, and are connected in series so that adjacent coils have opposite polarities. . Therefore, when magnetic flux in one direction is applied to all the coils 39, the voltage and current direction generated in each coil 39, or the direction of the coil 3
When a current is passed through the entire coil 9, the direction of magnetic flux generated in each coil 39 is opposite between adjacent coils, and external induction and noise are weakened by mutually impinging on each other between the adjacent coils.

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 M1 coil 35 in the X direction toward the other end on the opposite side, and the induced voltage becomes smaller due to the attenuation of the magnetostrictive vibration waves. It makes up for that. Generally, in order to increase the induced electromotive force, it is preferable that the winding pitch be large. This X
The second 22nd direction coil 39 is for detecting the induced voltage caused by the magnetostrictive imaging 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 the 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
The direction position detection section is inserted into a recess provided in the inner bottom surface of the non-magnetic metal case 311, and is connected to the magnetostrictive transmission medium 32, the reinforcing material 34, the first Y-direction coil 36, and the second Y-direction coil 310. 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 designating inner 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 made of non-magnetic metal or synthetic resin such as acrylic.
This indigo constitutes the input panel 312.

FIG. 6 shows the structure of a position designating magnetic generator (hereinafter referred to as a position indicator) 50, in which a cylindrical bar magnet 52 is placed at the tip of a pen-shaped container 51 with the N pole facing down. shrubbery,
Furthermore, a pen shaft 53 such as a ballpoint pen is provided inside the pen. Further, 54 is a spacer for holding down the bar magnet 52.

FIG. 7 is a circuit block diagram showing the configuration of the position detection circuit 40. Below, the configuration of each block of the position detection circuit 40 and the operation of the entire device will be described in detail.

Now, the position indicator 50 indicates the first position in the X direction of the tablet 30:
The electric machine It is assumed that magnetism is applied to the magnetostrictive transmission media 31 and 32 to the extent that the coupling coefficient becomes large.

When the power switch (not shown) of the position detection circuit 40 is turned on, the control circuit 41 outputs an output buffer. 42, the counter 43 is reset, and the X-direction pulse current generator 44 is operated. The counter 43 is a clock generator 45
clock pulse (pulse repetition frequency is, for example, 1
00MH7) starts counting.

The pulse current generator 44 for the X direction operates and the pulse current
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. do. This magnetostrictive vibration wave propagates along the elongated direction of the magnetostrictive transmission medium 31 at a propagation speed (approximately 5000 m/sec) specific to the magnetostrictive transmission medium 31. During this propagation, mechanical energy is converted into magnetic energy at a portion of the magnetostrictive transmission medium 31 where the magnetostrictive vibration wave exists, depending on the magnitude of the electromechanical coupling coefficient at that portion, so that An induced electromotive force is generated in the direction second coil 39.

FIG. 8 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 circuit, the amplitude of the induced electromotive force is at time 1-0 and at time t. It becomes large after t1 to t2 seconds have passed since then, and becomes small at other times. The reason why the amplitude of the induced electromotive force becomes large immediately after time 1-0 is due to the electromagnetic induction effect between the first X-direction coil 35 and the second X-direction coil 39. The amplitude of the induced electromotive force (induced 3g voltage due to magnetostrictive vibration waves) increases because the magnetostrictive vibration waves generated in the winding portion of the first coil 35 in the X direction propagate through the magnetostrictive transmission medium 31 and reach the position indicator 50.
This is because the electromechanical coupling coefficient becomes large at that point. 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, it is possible to calculate the position in the X direction specified by the position instruction 2350, that is, the distance 11. As shown in FIG. 8, the propagation time for calculating the position is, for example, the time t3 when the amplitude of the induced voltage due to magnetostrictive vibration becomes smaller than the threshold value -El, and the time t4 when it becomes larger than the threshold value E.
Alternatively, the zero cross point t5 may be used.

The induced electromotive force generated by the three X-direction second coils 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 three second coils in the X direction. Further, this value corresponds to the distance 11 in the X direction from the first coil 35 in the X direction to the position indicator 50 because the magnetostrictive vibration waves travel at a speed of about 5000 m/sec. The X-direction position data obtained by the counter 43 as a digital value in this manner is read into the control circuit 41 via the input cover noah 47.

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 in +'+ij. Thereafter, this is repeated at a predetermined period. By moving the position indicator 50, position data indicated one after another can be obtained.

Here, when a writing form (not shown) is placed on the input panel 312 and characters and figures are drawn on it using the position indicator 50 in the same way as when writing normally, a stroke is drawn on the writing form. In other words, the position indicator 50 is connected to the input panel 3.
12, the timing signal is sent from the timing detection circuit 20 to the position detection circuit 40 as described above. The timing signal is input to the input cover 7.
47 to the control circuit 41, and the control circuit 41
The X and Y direction position data during the period when the timing signal is output are sent to a computer etc. as input coordinate values.

According to the above configuration, the horn panel 31 containing the tablet 30
Coordinates cannot be input simply by placing the position indicator 50 on the input panel 312, and coordinates cannot be input even when the input panel 312 and the position indicator 50 are separated between the strokes of characters or figures. Since coordinates can only be input when the device is in contact and moved, it is possible to input handwritten characters, drawings, etc. with a natural feeling similar to normal writing. Further, since characters and figures are drawn on the entry form using the pen shaft 53 of the position indicator 50, it is possible to check what data has been input without looking at the display device or the like. In addition, the position indicator 5o does not require a switch or other wake circuit, as well as a cord.
It can be manufactured easily and inexpensively.

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 the magnetostrictive imaging wave, it may be reversed. In that case, a magnetostrictive vibration wave is generated directly under the position indicator 50, and the second coil 39
．． At 310 an induced pressure will be generated.

In addition, although the above-mentioned embodiment was applied to the transmission of magnetostrictive vibration waves, it is also possible to use the electromagnetic induction of a magnetic body.

(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, the imaging pickup attached to the input panel and a timing detection circuit that extracts only the signal caused by the vibration generated when the position specifying magnetic generator is moved on the input panel from the output signal of the vibration pickup, so the position specifying magnetic generator can be used on the input panel. It is possible to extract a timing signal corresponding only to the period during which the generator is brought into contact with the input panel and moved, making it possible to input the coordinates of handwritten characters and figures in a natural manner similar to normal handwriting. , for the magnetic generator for position specification.
Of course, there is no need for switches or other electrical circuits,
It has the advantage of being easy to manufacture and provide at low cost.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIGS. 1 to 8 show an embodiment of the position detection device of the present invention, FIG. 1 is an explanatory diagram showing the outline thereof, and FIG. 2 is a vibration pickup and Fig. 3 is a plan view showing the structure of the timing detection circuit, Fig. 4 is a cross-sectional view taken along line A-A in Fig. 3, and Fig. 5 shows magnetic bias versus electric machine. A characteristic diagram of the coupling coefficient, Fig. 6 is a sectional view showing the structure of the magnetic generator for position specification, Fig. 7 is a block diagram of the position detection circuit, and Fig. 8 is the X
A diagram showing an example of a temporal change in the induced electromotive force generated in the second coil in the direction, and FIG. 9 is an explanatory diagram showing an example of a conventional position detection device. DESCRIPTION OF SYMBOLS 10... Vibration pickup, 20... Timing detection circuit, 30... Tablet, 312... Input panel, 40... Position detection circuit, 50... Magnetic generator for position specification. Figure 1 Figure 2 Figure 3 Figure 5 Figure 8

Claims (1)

[Claims] In a position detection device that detects a position specified by a position specifying magnetic generator that generates a steady magnetic field, the position specifying magnetic generator is input using a vibration pickup attached to an input panel and the output signal of the vibration pickup. A position detection device characterized by comprising a timing detection circuit that picks up only signals caused by vibrations generated when the panel is moved.