JPS6143754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a coordinate reading device using a magnetostrictive material as a vibration propagation medium.

Specifically, magnetic disturbances intentionally or negligently applied to a vibration propagation medium made of a magnetostrictive material, such as bringing a magnet or an office tool attached with a magnet close to the vibration propagation medium, or placing it on the vibration propagation medium. If the magnetized state of the vibration propagation medium is disturbed due to
The object of the present invention is to provide a novel and useful coordinate reading device that can automatically restore the vibration propagation medium to a regular magnetized state.

As is well known, a coordinate reading device is a device that can perform coordinate analysis of graphic pattern diagrams in various fields and input the analyzed data into a computer or the like to construct various labor-saving systems.

Among these types of devices, devices that utilize the delay of magnetostrictive vibration waves in magnetic materials are often used because they are structurally friendly and easy to handle.

Here, a general outline of the coordinate reading device as described above will be explained with reference to FIG.

The device is composed of a tablet 1, a detector 2 consisting of a pickup coil, and an input/output control section 3 electrically connected to these. In addition, 4 is optionally connected to the input/output control unit 3 to provide various labor-saving systems.
For example, a group of external connection devices for configuring an automatic drafting device or the like is shown.

The reading operation is performed by setting any graphical pattern drawings in various fields such as circuit design drawings, electrocardiograms, X-ray photographs, and maps on the tablet 1, and then using the pen-shaped or cursor-shaped detector 2.
It tracks the graphic pattern of the set drawing.

In other words, the above figure pattern is analog data, and it is
This is detected as axis and Y axis displacements, converted into digital quantities by the human output control unit 3, and inputted as X and Y coordinate data to an externally connected device, such as a computer or a printer.

As described above, this device performs coordinate analysis using the delay of magnetostrictive vibration waves propagating in a magnetic material when measuring X-axis and Y-axis displacements. Therefore, the tablet 1 has two types of magnetostrictive vibration propagation paths Lx and Wx which are vibrated by the excitation windings Wx and Wy to propagate magnetostrictive vibration waves in the X and Y axis directions.
Configure so that Ly can appear.

There are the following two methods for creating these two types of magnetostrictive vibration propagation paths Lx and Ly.

One method is to form a thin plate of magnetostrictive material obtained by rolling or peeling after plating on a suitable base plate into a rectangular shape with the required area. excitation winding
There are forms with Wx and Wy applied. However, in this case, each concrete propagation path as shown in Figure 1
Lx and Ly are not visible externally.

Another method is to use two thin plates of magnetostrictive material similar to those described above, one for the X-axis and the other for the Y-axis, and process them using photoetching technology to create many parallel plates. By making slits, a concrete multi-layer magnetostrictive vibration propagation path Lx as shown in Figure 1 can be created.
Or get Ly. Of course, the transmission path in these two images
Lx and Ly constitute one common plane coordinate. Then, after stacking these two magnetostrictive material thin plates with an appropriate insulating sheet interposed so that their respective slits are perpendicular to each other, and fixing each side edge with adhesive, etc., the X and Y axis components are Excitation winding
Wx and Wy are applied to each side of the thin plate.

In the tablet 1 in either of the two configurations described above, an excitation pulse current is now applied to each excitation line Wx or Wy in order to vibrate the thin plate of magnetostrictive material. An excitation magnetic field is then generated, which excites the thin plate and causes magnetostrictive vibrations. This vibration then progresses through each propagation path Lx or Ly toward the other end. Here, let us assume that the measurement point is P in the figure, and that a conventional detector consisting of a pick-up coil is brought close to this point P. However, the change in magnetic flux caused by the magnetostrictive vibration that has progressed to point P induces a voltage in the detector coil. Since the propagation delay time of such a vibration wave corresponds to distance on the coordinate axis, the time difference between the detection time at point P and the time when the pulse current was applied to the excitation line, that is, the delay time, can be calculated by counting clock pulses, etc. By measuring, the X and Y axis coordinate values of point P can be read. Further, the X-axis component and the Y-axis component are read alternately.

Furthermore, although FIG. 2 shows the above-mentioned tablet 1 in a practical form, when developing the above-mentioned reading operation, the main part of the tablet 1, that is, the vibration propagation medium made of magnetostrictive material, is It is magnetized in order to excite it to an appropriate magnetic potential, and this magnetization is repeated at a predetermined period depending on the frequency of reading operations, elapsed time, etc. This was carried out by slowly moving a bar magnet 5 as shown in the figure from one corner of the tablet 1 in a diagonal direction (in the direction of arrow 6).

Therefore, such a magnetizing operation is an operation that is always required at least once at the beginning of a series of reading processes, but the magnetizing operation by the bar-shaped magnet 5 is performed by the vibration propagation formed by the magnetostrictive material housed in the tablet 1. Unless the medium is magnetized uniformly and in a fixed direction, the coordinate reading function of the device will be disabled, so the force control requires considerable skill and is unexpectedly difficult. Ta. Furthermore, depending on how the bar magnet 5 is moved, the reading accuracy of the tablet changes greatly, and the reading accuracy also changes depending on whether the front or back side of the magnetizing bar magnet 5 faces the tablet 1 side. It has the disadvantage that accuracy varies, which is extremely inconvenient to handle. (Moreover, it is necessary to perform these rather difficult and delicate operations repeatedly every time the excited (magnetized) state of the vibration propagation medium made of magnetostrictive material attenuates.
This has been a major drawback of this type of coordinate reading device. Note that 11 in FIG. 2 indicates the effective reading area of the tablet 1, and this area 11
is also the opening of the device housing 12 outside the tablet.

Furthermore, in the conventional device, on the tablet 1,
When a magnetic disturbance is applied to the magnetostrictive material inside the tablet 1, such as when the magnet 7 is brought close to or placed on the tablet 1, the previously applied magnetization effect is disturbed.
There is a drawback that the reading accuracy and the reading function itself are greatly impaired, so by eliminating the source of magnetic disturbance such as the magnet 7 from the tablet, and by magnetizing the tablet 1 as described above, There was the hassle of having to re-magnetize the magnet. In particular, objects that are a source of magnetic disturbance, such as the magnet 7 illustrated, exist attached to familiar items such as office supplies, and in a reading work environment using this type of device, environmental management must be extremely careful. Unless this is done, magnetic disturbance objects cannot be avoided. Further, if the operator performs the required coordinate reading operation without knowing that such a magnetic disturbance effect has been applied to the tablet 1, the actual damage that can be predicted may be extremely severe.

Therefore, the present invention focuses on improving the magnetization process of the conventional device, which causes such great disadvantages.
The gist is that a fixed magnetized coil is used to apply magnetization with substantially uniform regularity to the effective reading area of a vibration propagation medium formed from a magnetostrictive material. The coordinate reading device comprises a magnetizing current supply means for supplying a required magnetizing current to the fixed magnetizing coil.

Therefore, the magnetization operation becomes extremely easy, and there is no need for any manual magnetization operation, and even if a magnetic disturbance effect is intentionally or negligently applied,
At the same time as the disturbance source is removed, the tablet 1 is automatically returned to its original magnetized state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on some embodiments thereof with reference to the drawings.

FIG. 3 is an explanatory diagram when the coordinate reading device according to the present invention is a uniaxial type, and FIGS. 4 and 5 are explanatory diagrams when the coordinate reading device according to the present invention is configured to be applied to each coordinate of a biaxial type.
0, 20x, 20y, and 20' are fixed magnetizing coils that magnetize the vibration propagation medium in a direction parallel to the plane.

Each of these fixed magnetized coils 20, 20x, y, 2
0' is the vibration propagation medium 1 made of the required magnetostrictive material.
However, in the form of wrapping around it,
Each fixed magnetizing coil 20 is wound so as to accurately magnetize the effective reading area of each vibration propagation medium 1, for example, the portions 11 in FIG. 3 and 11x and 11y in FIG. , 20x, y, and 20' are connected to a predetermined magnetizing current supply means 30, so that the vibration propagation medium 1 can be magnetized with substantially uniform regularity. Further, Wx and Wy in the figure are vibration excitation windings for generating magnetostrictive vibration waves in the X-axis and Y-axis directions, as described in FIG. 1.

In the biaxial tablet shown in Figs. 4 and 5, the fixed magnetizing coils 20X and 20y (Fig. 4) may be magnetized and energized simultaneously, or individually at appropriate intervals depending on the reading conditions. It may also be excited. In particular, the coil 20' in FIG. 5 is wound in a manner obliquely intersecting the traveling direction of the vibration waves Xw, Yw generated from the magnetostrictive vibration excitation windings Wx and Wy. It is preferable that the angles θx and θy are approximately equal, or that they have a substantially complementary angle relationship when the coil 20' is wound along the diagonal of the effective reading area that is approximately rectangular. .

Further, the magnetizing current supplying means 30 may apply an arbitrary magnetizing current depending on the characteristics of the tablet 1, but for example, as shown in FIG. It may be configured to include a magnetizing current pulse generating circuit 32 capable of generating current pulses and a timing control circuit 31 for generating the magnetizing current pulses at appropriate timing, or as shown in FIG. It may be configured to include a DC direct current generation circuit 32' that generates a magnetizing current and the timing control circuit 31' described above. Of course, there is no problem in practical use even if the magnetizing current supply means described above includes either a magnetizing current pulse generating circuit or a DC magnetizing current generating circuit alone.

FIG. 6 shows a timing chart correlating between the magnetizing action and the reading operation by each magnetizing current supply means 30 in FIGS. 4 and 5 described above, and FIG. This is the case in the magnetizing current supply means shown in FIG.

In the figure, TE indicates the magnetization period, Tx indicates the reading period of the X-axis coordinate value, and Ty indicates the reading period of the Y-axis coordinate value.

30P and 31p are trigger pulses for the magnetizing current pulses, which are controlled by the timing control circuit 31 under the magnetizing output pulses of the magnetizing current pulse generating circuit 32 to the fixed magnetizing coils 20x and 20y or at appropriate timing. -ing

At the same time, the timing control circuit 31 can also control the excitation timing of the excitation windings Wx and Wy for each axis of the tablet 1. In such a case, individual magnetizing current pulses are applied to the fixed magnetizing coils 20x and 20Y for the X-axis and Y-axis by the trigger pulse 31p from the timing control circuit 31, for example, at the beginning of the X-axis coordinate reading period Tx. coil 20x
Then, a magnetizing current pulse may be supplied to the coil 20y at the beginning of the period Ty.

Figure 6B shows the case where DC magnetizing currents 30P and 32P' are added to the fixed magnetizing coil 20', and Tx,
Ty indicates the reading period of the X and Y axis coordinate values as described above. Tp is the trigger timing chart of the excitation windings Wx and Wy. In this case, that is, in the case of FIG. 5, the timing control circuit 31' controls the DC magnetizing current generating circuit 32' at least during the beginning and end of the series of coordinate reading operations, so that the required DC magnetizing current coil 20'
All you have to do is act so that it flows. That is, it may have a switching effect.

The control system based on each of these timing charts can be selected as appropriate depending on the reading process in one-shot mode or continuous mode in this type of device, and by programming the timing chart, the device operability can be adjusted to suit each usage condition. can be obtained.

In addition, in the case of the oblique fixed magnetized coils 20' and 20A' as shown in FIG. The angles θx and θy formed by the conductors of the magnetizing coils 20' and 20A' can be arbitrarily set.

As explained above, the coordinate reading device according to the present invention is configured to include a fixed magnetizing coil and a magnetizing current supply means for applying a required magnetizing current to the coil. It has the advantage of saving the labor of the difficult and complicated magnetizing operation and making it even easier and automatic, as well as quickly and automatically recovering from intentional or negligent magnetic disturbance. In addition to facilitating the simplification of reading operations in this type of device, it can also promote stability and sophistication of reading accuracy. It is.

Incidentally, the effects of the above-mentioned apparatus of the present invention will be specifically shown together with experimental data in FIG.

The diagram in FIG. 7 shows the output waveform of the pickup coil after the magnetostrictive material is uniformly magnetized with a permanent magnet.

Therefore, FIG. 7a shows the output waveform of the magnetostrictive material in the conventional coordinate reading device, which is a normal waveform, and FIG. 7c shows the output waveform of the magnetostrictive material in the coordinate reading device of the present invention. This is also a normal waveform.

However, when a magnetic field as a disturbance is applied locally to the magnetostrictive material of the conventional coordinate reading device according to FIG. As shown in Figure 7b, abnormal disturbances appeared in the phase and amplitude values of the output voltage of the pickup coil, and it was no longer possible to normally detect the coordinate position, and the function of the coordinate reading device could no longer be fulfilled. Put it away.

On the other hand, in the case of the coordinate reading device of the present invention configured by adopting the automatic magnetization method, the output waveform after removing the permanent magnet is shown in FIG. 7d, which is exactly the same as that in FIG. 7c. Therefore, it is clear that there is no change in the output waveforms before and after the application of the magnetic field as a disturbance.

Therefore, as is clear from such experimental results, according to the present invention, even if office supplies etc. equipped with magnets are placed near magnetostrictive materials inadvertently or intentionally, the source of the disturbance magnetic field can be removed. This makes it possible to realize a coordinate reading device having the characteristic of automatically returning to the original normal waveform.

Thus, the present invention has been proven to be a very effective technology with a wide range of applications, as it completely solves the disturbance problem, which was the biggest problem with the conventional coordinate reading system.

The present invention can be applied to well-known tablets made of magnetostrictive material constructed by combining linear or ribbon-shaped rolled materials in a lattice shape, and known flat or ribbon-shaped tablets made of rolled materials such as nickel or permalloy. Alternatively, it can also be applied to tablets made of linear magnetostrictive material.In other words, it can be easily applied to any position detection device, regardless of the composition, magnetic properties, or structure of the magnetostrictive material. I would like to add that this is completely self-evident.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram for explaining the general configuration outline, operating procedure, and operating principle of a conventional coordinate reading device and this type of device, and Fig. 2 is an explanatory diagram for explaining the conventional magnetization form. , Figures 3 to 6 relate to some embodiments of the coordinate reading device according to the present invention, in which Figure 3 is a uniaxial type, and Figures 4 and 5 are schematic configuration explanatory diagrams of the main parts of a biaxial type tablet. , FIG. 6 is a chart showing a timing chart in relation to the magnetizing current supply means and the reading operation in FIGS. 3 to 5, and FIG. 7 shows experimental data of the conventional magnetostrictive material and the device of the present invention. Figure 7a is a diagram showing the output waveform of the pickup coil after uniformly magnetizing a conventional magnetostrictive material, and Figure 7b is a diagram showing the output waveform of a pickup coil after uniformly magnetizing a conventional magnetostrictive material. Fig. 7c is a diagram showing the output waveform of the pickup coil after removing the magnetic field, Fig. 7c is a diagram showing the output waveform of the device of the present invention under normal conditions, and Fig. 7d is a diagram showing the output waveform of the pickup coil after the magnetic field is locally applied as a disturbance to the device of the present invention. FIG. 3 is a diagram showing an output waveform after applying and removing this. In the figure, 1 is a vibration propagation medium made of magnetostrictive material, 2
0, 20x, 20y, 20', 20A, 20A',
20B, 20C, 20D are fixed magnetizing coils, 30
is a magnetizing current supply means.

Claims (1)

[Scope of Claims] 1. In a coordinate reading device capable of reading coordinates in at least one dimension using a magnetostrictive material as a vibration propagation medium, the entire effective coordinate reading area of the vibration propagation medium is substantially uniform. at least one fixed magnetizing coil arranged in a manner wound around the vibration propagation medium to magnetize the vibration propagation medium parallel to a plane with regularity; The magnetizing current pulse generation circuit is configured to include a magnetizing current pulse generation circuit that can generate magnetizing current pulses with a predetermined regularity in order to add a required magnetizing current, and a timing control circuit that controls the timing of magnetizing current pulse generation. 1. A coordinate reading device comprising at least one magnetizing current supply means. 2. The fixed magnetized coil is formed in an oblique shape, and the oblique angle between the conductor of the fixed magnetized coil and the line connecting the front edge of the magnetostrictive vibration wave propagating in the vibration propagation medium is arbitrarily set. Claim 1 is characterized in that it is configured such that it can
Coordinate reading device as described in section.