JPS59188519A - Magnetism developing body - Google Patents

Abstract

PURPOSE:To confirm by eye the magnetized state by magnetizing by patterning a magnetic medium by the prescribed pattern. CONSTITUTION:A magnetic scale is obtained by spreading or painting the magnetic medium 1 on a nonmagnetic material 2, etching the medium to the necessary pattern, and then magnetizing it. The magnetization effected by passing the scale after the etching through a uniform magnetic field. The confirmation is possible by eye in the inspection of the magnetization inversion length and the mutual relation among the tracks, and the titled body is suitable for mass production. The medium 1 is provided in the material 2 as shown in the figures, and dot and X marks indicate the magnetizing direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a novel magnetic generating body, particularly to a magnetic generating body used in combination with a magnetic sensor.

[Prior art]

Conventionally, one application example of a magnet generating body used in combination with a magnetic sensor is a magnetic encoder that detects position or angle. In this case, the magnetizing body functions as a so-called magnetic scale that is magnetized according to position and angle signals.

The present invention will be explained below using a magnetic scale as an example.
The present invention is not limited to this, but can be applied to various devices that utilize magnetism. FIGS. 1 and 2 show conventional magnetic scales. In each case, FIG. 1 shows the case where in-plane magnetization is used, and FIG. 2 shows the case where perpendicular magnetization is used, and in both cases, l is a magnetic medium and 2 is a non-magnetic material.

Further, arrows, ■, and ■ indicate the direction of magnetization (the same applies below). In these magnetic scales, a magnetic medium is generally deposited or applied onto a non-magnetic material and then magnetized so that adjacent portions are oriented in opposite directions. Therefore, in the conventional case, a complicated device is required for magnetization, and it is not easy to confirm whether the magnetization reversal length and the relationship between tracks are correctly magnetized, which makes it unsuitable for mass production. there were. Furthermore, in the case of in-plane magnetization, the magnetization reversal length becomes large.
Due to its characteristics, in the second-place track, the magnetic field becomes very small at the center of each magnetized region, and even in the case of perpendicular magnetization, the self-demagnetization effect becomes more pronounced in the upper track. The magnetic field tends to be smaller in the Therefore, in the conventional magnetic scale, since a magnetic field of uniform strength cannot be obtained particularly in the upper track, there is a risk that the magnetic sensor may cause a detection error.

In addition, not only magnetic scales but also magnetized bodies with large areas of magnetized portions had similar conspicuous points.

〔the purpose〕

The purpose of the present invention is to eliminate the disadvantages of the conventional example in a magnetic scale, and at the same time, to solve the problem in a magnetic sensor in a magnet generating body having an aspect ratio close to 1 and a relatively large area of magnetized portion. The object of the present invention is to provide a magnet generating body capable of applying a magnetic field of uniform strength.

[Example 1, 2] Figures 3 and 4 show cases in which the present invention is applied to a magnetic scale as examples of the present invention, respectively. Figure 3 is similar to Figure 1, and Figure 4 is similar to Figure 4. They correspond to Figure 2. These magnetic scales are obtained by depositing or coating a magnetic medium on a non-magnetic material, etching it into a desired pattern, and then magnetizing it. For magnetization, the scale after etching may be passed through a uniform magnetic field, and a simple magnetization device may be used. Further, in order to inspect the magnetization reversal length and the relationship between tracks, conventionally a special viewer or device was required, but according to the present invention, visual confirmation is sufficient. Therefore, it can be said that it is suitable for mass production. Note that the part where the magnetic medium has come out due to etching may be left as is, but if it is filled with non-magnetic material as shown in Figures 3 and 4, the surface of the scale can be made smooth, so the magnetic sensor can be attached to the scale. This is effective when sliding in contact with the object.

[Embodiment 3] Next, a method for preventing detection errors of the magnetic sensor due to a decrease in the magnetic field at the center of the magnetized region will be described. FIG. 5 shows a third embodiment of the invention. By dividing the magnetized region in the scale width direction and changing the direction of in-plane magnetization so that the pitch S of the stripes is smaller than the minimum magnetization pattern (S < l), the magnetization before division in the width direction is There is no decrease in the magnetic field at the center of the area, and a magnetic field of uniform strength (in the direction perpendicular to the scale main surface) can be obtained for the magnetic sensor.

[Embodiment 4] FIG. 6 shows another embodiment of the present invention in which the present invention is applied to the scale shown in FIG. 4.

In this case, as in Fig. 5, by dividing the magnetized region in the scale width direction and using the edge magnetic field of the region, a nearly uniform strength is applied to the magnetic sensor over the entire region of each magnetized region. A magnetic field of 300 mm can be obtained.

Note that even if FIG. 5 is divided as shown in FIG. 7, the same effect can be obtained. FIG. 8 shows the effect of the present invention calculated by numerical analysis in the case of a Go-Or perpendicular magnetization medium. Figure (a) shows a cross-sectional view of the scale in a direction perpendicular to the scale main surface and perpendicular to the division direction, and figure (b) shows a cross-sectional view of the scale when the coordinate axes are taken as in figure (a). This is the X-direction distribution of the magnetic field strength HY in the y-direction, and the values are relative. It can be seen that by dividing the medium into 115 parts, the concave distribution of the magnetic field strength is eliminated and a stronger magnetic field is obtained (solid line) compared to the magnetic wire. The division of this magnetized region is
It is only necessary to perform this for regions where a magnetic field of uniform strength cannot be obtained, and there is no need to divide the entire region. In addition to using a non-magnetic material as in the above-mentioned embodiment for division, a gap may be provided. Note that the optimal values for the width and pitch of the divisions vary depending on the magnetic medium, its thickness, magnetization direction, etc., but since they can be determined by a known numerical analysis method using a computer, the details will be omitted.

Among the magnetic media in the above embodiments, in-plane magnetized media (for example, γ-Fe 203.Cr 0 as a coating type)
2.

Metal tape River Fe alloy, Go-Ni as vapor deposition type
) has been used for a long time, is stable, and its reliability has been confirmed. and,
Perpendicularly magnetized media (for example, Go-R, etc.) have steep magnetization reversals at the edges, so when used in magnetic scales, position errors can be reduced. Also,
Among in-plane magnetization media, vapor deposition type media and perpendicular magnetization media can be made thinner, so they have the effect of making it possible to form fine patterns.

Note that the magnetic medium may be a soft magnetic material such as permalloy. In this case, if a bias magnetic field is applied, for example by attaching a rubber magnet to a magnetic sensor, the soft magnetic material will be magnetized each time the sensor approaches, eliminating the need to magnetize it in advance. At the same time, a magnetizing device is also not required.

On the other hand, if a flexible material such as polyester or polyimide is used as the base material, a rotary magnetic encoder can be constructed by attaching it to a cylindrical object and combining it with a magnetic sensor.

Furthermore, a magnetic encoder may be constructed by using a magnetoresistive multi-head (MR head) as a magnetic sensor and combining it with the present invention. Unlike Hall elements and ring-type magnetic heads, MR heads can obtain output regardless of whether the static magnetic field or the magnetic field is positive or negative. This is particularly effective when the output does not become zero (see Figure 8).

Although the above description has been made regarding the magnetic scale of a magnetic encoder, the present invention is not limited thereto, and can be applied to all magnetizing bodies according to the claims that are used in combination with a magnetic sensor.

〔effect〕

As explained above, the present invention has the following effects.

(1) A magnetizing device is simple or unnecessary, and the state of magnetization can be visually confirmed.

(2) A magnetic field of uniform strength can be applied to the magnetic sensor, and detection errors can be prevented.

(3) When a soft magnetic material is used as the magnetic medium, changes over time as a magnetizing material can be ignored.

(4) By using a flexible material as the base material and attaching it together with a magnetic sensor to the lens barrel of a camera, the position of the lens and the state of the aperture can be detected.

(5) If a magnetic encoder is constructed using a magnetoresistive multi-sensor as a magnetic sensor, the position can be detected over a long distance with high precision.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing a magnetic scale of a conventional magnetic encoder, FIGS. 3 to 7 are explanatory diagrams of an embodiment in which the present invention is applied to a magnetic scale, and FIG. a) and (b) are explanatory diagrams of the distribution of magnetic field strength showing the effects of the present invention, respectively. 1-----1 magnetic medium (magnetized region) 2-----1 non-magnetic material

Claims (5)

[Claims] (1) A magnet generating body in which a magnetic medium is provided on a non-magnetic material, wherein the magnetic medium is patterned into a predetermined pattern and magnetized. (2) The magnetic body according to claim 1, wherein at least a portion of the magnetic medium is divided into a plurality of stripes by a gap or a nonmagnetic material. (3) The magnetic generating body according to claim 1, wherein the magnetic medium is an in-plane magnetized medium. (4) The magnetic generating body according to claim 1, wherein the magnetic medium is a perpendicularly magnetized medium. (5) The magnetic generating body according to claim 1, wherein the magnetic medium is a soft magnetic material.