JPS5856912B2 - 2D magnetic scale device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that can read the XY coordinates of any point on a scale plate surface.

This type of device is useful for drawing, reading drawings and maps for computer input, reading figures for transmitting handwritten figures, etc., and there are products from various companies called digitizers.

These conventional products are generally as follows.

A large number of conductive wires are arranged vertically and horizontally at regular intervals on the scale plane, that is, in the X and Y directions, and the wires in the Y direction are set at a constant frequency Fx.
An AC voltage of a different frequency FY is applied to the line in the X direction with a phase shift of Aψ, and an AC voltage of a different frequency FY is applied with a phase shift of Aθ.

The frequency FX, FY and phase ψ, θ at an arbitrary position are read by a probe using electrostatic or electromagnetic induction, and from this the X and Y coordinates of that position are found.

However, such conventional products have the following drawbacks.

■ It is necessary to embed electric wires or electrodes on the scale plate surface.
The structure is complex.

■ A detection cable must be connected to the scale plate.

■ Detection signals are extremely critical and easily affected by external influences, resulting in unstable operation.

■ Absolute accuracy is low compared to resolution.

The present invention eliminates the above drawbacks by using a magnetic sensor head that uses magnetism in the scale plate to detect the magnetic scale, and digitally measures the displacement of the magnetic sensor head in the X and Y directions and the XY coordinates. It is something.

Hereinafter, the present invention will be specifically explained using the drawings.

1 to 4 are explanatory diagrams showing the principle of the present invention.

In FIG. 1, 1 is a magnetic pattern magnetized on a planar magnetic sheet, and 2 is an X-direction magnetic detection head (arrows indicate the detection direction).

), 3 shows the output waveform of the same head.

A magnetic pattern like No. 1 has an N, S alternating magnetic field in the X direction, but the magnetic field does not change in the Y direction.

Therefore, if the X-direction magnetic sensing head 2 is moved in the
I don't get any output like this.

Therefore, with a magnetic pattern like No. 1, the length in the X direction can be measured, but the length in the Y direction cannot be measured.

In FIG. 2, 1' is another magnetic pattern magnetized on the magnetic sheet, and 2' is a Y-direction magnetic detection head (the arrow indicates the detection direction).

) and 3' indicate the output waveforms of the same head.

A magnetic pattern like 1' has an N, S alternating magnetic field in the Y direction, and the magnetic field does not change in the X direction.

Therefore, if the Y-direction magnetic detection head 2' is moved in the Y direction, an output with a waveform as shown in 3' can be obtained, but such an output cannot be obtained even if it is moved in the X direction.

Therefore, with a magnetic pattern like 1', the length in the Y direction can be measured, but the length in the X direction cannot be measured.

In FIG. 3, 1" indicates the magnetic pattern obtained by superimposing the magnetic patterns 1 and 1', and 2°2',
3 and 3' are the same as shown in FIGS. 1 and 2.

In a magnetic pattern like 1", the north pole is X. The south pole is the diagonal point of the lattice points arranged at a constant pitch λ in the Y direction. N in both Y directions.

It is an alternating magnetic field of S.

Each detection area width is λ on this magnetic pattern (plane).
X equal to

Y-direction When the magnetic detecting body that integrates each magnetic detecting head 2, 2' is moved in the X direction, the X-direction magnetic detecting head 2 obtains an output like 3, but the Y-direction magnetic detecting head 2' cannot obtain such output.

Conversely, when the magnetic detecting body is moved in the Y direction, the Y-direction magnetic detecting head 2' obtains an output such as 3', but the X-direction magnetic detecting head 2 does not obtain such an output.

However, if the magnetic detecting body is moved too much,
, 3 and 3 independently in each magnetic detection head 2 and 2' in the Y direction.
Since an output like ' is obtained, each moving component in the X and Y directions can be measured.

That is, in FIG. 4, when the magnetic sensing body is moved from point A to point B, the amount of movement Ax in the X direction and the amount of movement JY in the Y direction can be measured.

Therefore, on a magnetic scale plate on which a magnetic sheet is magnetized with a magnetic pattern as shown in FIG. When the point is moved, the XY coordinates of that point can be read, and when the point is moved to any other point, the XY coordinates of the new point can be read by measuring the movement displacement.

This is the principle of the invention. The magnetic pattern in FIG. 3 1'' has an X as described above.

The lattice points arranged with a constant pitch λ in the Y direction are N
The pole and its diagonal point are magnetized as S poles, but the actual magnetization pattern is as shown in FIG.

When the X or Y direction magnetic detection head 2 or 2' moves on such a magnetic pattern, the detection area width in the Y or X direction of the X or Y direction magnetic detection head 2 or 2', that is, the detectable length. If the pitch is set equal to the pitch λ of the magnetic pattern 1'', the output of the magnetic detection head will not change in the direction perpendicular to the detection direction.

In FIG. 6, reference numeral 2 denotes an X-direction magnetic detection head similar to that in FIG. 1, but in this figure, the head is shown close to the actual structure.

When this X-direction magnetic detection head 2 moves in the direction of the arrow, that is, in the X direction, the detection head 2 moves in the direction perpendicular to the detection (movement) direction, that is, in the Y direction, as shown in FIGS. Also, if the detection area width of the magnetic detection head 2 is equal to the pitch λ of the magnetic pattern 1'', the magnetic detection head 2
The output of does not change.

This also applies to the Y-direction magnetic detection head 2'.

Furthermore, by providing one or more pairs of each magnetic detection head, that is, by creating a multi-head structure, the magnetic sensor is insensitive to uniform unnecessary magnetic fields and does not malfunction even if each magnetic pole band of the magnetic pattern is intermittent. can be configured.

However, for convenience, in this specification, a sensor consisting of only one magnetic detection head will also be referred to as a magnetic sensor.

FIG. 7 is a side view showing an example of a magnetic sheet used in the present invention.

In the figure, 4 is an iron plate, and 5 is a barium ferrite rubber magnet stuck thereon.

Magnetization of the magnetic pattern 1'' onto the magnetic sheet is performed, for example, as follows.

First, as shown in FIG. 8, grooves 7 in the shape of a base or lattice are cut into the iron block 6.

The pitch of the grating is equal in both the vertical and horizontal directions, that is, the X-axis and Y-axis directions, and is, for example, 21nrIL.

The width and depth of the groove 7 are both 0.8 degrees, for example.

Next, as shown in FIG. 9, a conductive wire 8 is wound around the iron block 6 along the lattice grooves 7 to produce a magnetizer.

Then, when the surface of this magnetizer is aligned with the surface of the rubber magnet 5 of the magnetic sheet as shown in FIG. 7, and a current of about 40 OA is momentarily passed through the conductor 8, the direction of the current becomes as shown in FIG. 9. ■
A magnetic field as shown in (2) is generated and a magnetic pattern 1'' is obtained.

As shown in FIG. 10, a surface protection stainless steel plate 9 made of a non-magnetic material can be attached to the thus magnetized magnetic sheet.

Since the magnetic scale of the magnetic scale plate obtained as described above has an X axis and a Y axis, two magnetic sensors that are perpendicular to each other are fixed and integrated in parallel to these X and Y axes, respectively. , this integrated magnetic sensor,
Provide a means that can freely move while maintaining a parallel relationship with both the X and Y axes (maintaining a constant axial relationship), and provide a means to connect to each magnetic sensor and measure the detected magnetic scale. These movable support means and measuring means, which can obtain a two-dimensional magnetic scale device, are
Since it can be configured more easily than the prior art, detailed explanation will be omitted.

Furthermore, it goes without saying that suitable means for displaying the read data should be provided.

As is clear from the above description, the present invention has many advantages over conventional ones as follows.

(a) The surface of the magnetic scale requires only a flat rubber magnet, so the structure is simple.

(b) There is no need to connect the detection cable to the scale plate, and it can be separated from the main unit and moved freely.

(c) The detection signal is large and is less susceptible to external influences.

In other words, the operation is stable. 2) Since the scale surface can be protected with a non-magnetic metal plate, it can be used in adverse environments.

(e) Since the structure of the scale is simple, there are few steps, and it can be manufactured in a short time and at low cost, so mass production is possible.

(c) The scale plate can be made as large as necessary due to manufacturing advantages.

(g) Detection time is relatively short and high-speed reading is possible.

(To) Higher absolute accuracy than conventional ones.

It goes without saying that the present invention is not limited to the above-described embodiments, and can be modified and changed in various ways.

[Brief explanation of drawings]

1 to 4 are explanatory diagrams showing the principle of the present invention, FIG. 5 is an actual magnetization pattern diagram of the magnetic pattern in FIG. 3, FIG. 6 is an explanatory diagram of the detection area width of the magnetic detection head, and FIG. FIG. 7 is a side view showing an example of a magnetic sheet, FIGS. 8 and 9 are explanatory views showing an example of a method of magnetizing a magnetic scale plate, and FIG. 10 is a side view showing another example of a magnetic sheet. . 4.5 4,5,9...Magnetic sheet (magnetic scale plate), λ...Pitch, 2...X-axis direction magnetic sensor, 2'... ...Y-axis direction magnetic sensor.

Claims (1)

[Claims] 1 Set the X-axis and Y-axis on a planar magnetic sheet,
A magnetic scale plate in which each grid point arranged at a constant pitch in the X- and Y-axis directions is magnetized as a north pole and its diagonal point as a south pole, and a detection area width in the Y-axis direction equal to the above pitch is used. a magnetic sensor that detects a magnetic scale in the X-axis direction;
A magnetic sensor that detects a magnetic scale in the Y-axis direction that has a detection area width equal to the pitch in the X-axis direction, and a magnetic sensor that detects a magnetic scale in the Y-axis direction, and
A two-dimensional magnetic scale device comprising means for supporting the scale so as to be movable while maintaining a constant axial relationship with the axis, and means for reading the magnetic scale in the X-axis and Y-axis directions by being connected to each of the magnetic sensors.