JPS63234728A - Absolute magnetic encoder - Google Patents

Abstract

PURPOSE:To facilitate an assembling and to attain miniaturizing by forming a magnetic reluctance element film pattern on the substrate surface parallel to the disk surface, forming a lead film and a terminal part on the surface which is not parallel to the disk surface and forming the terminal part on a disk inner diameter respectively. CONSTITUTION:A magnetic resistance element film pattern 5 exists on a surface approximately parallel to a disk 2, a lead film 6 and a disk surface are located at the position away from a disk surface and a terminal part 7 is away from the disk surface by 1 mm or above in order to execute a soldering. Since at the time of assembling the magnetic resistance element of such a constitution, it is not necessary to pay attention to the bending of the whole of a substrate 4 surface and attention may be paid to the bending of a magnetic resistance element film part, the yield based on the disconnection at the time of assembling is widely improved. Since the terminal part 7 is within the disk dimension, the miniaturization can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an absolute position detector for drive and control motors in products such as robots and manipulators.

(Prior Art) There is a need for an absolute position detector that accurately measures the absolute position of an actuator that performs rotational or linear motion and is incorporated into a robot or manipulator. Conventionally, photoelectric detectors have been frequently used as such absolute position detectors.

This photoelectric detector consists of an optical slit made by photolithography of a metal film deposited on a glass disk, a light emitting diode, and a photodiode as a light receiving element. Due to the arrangement of the elements, it is impossible to make the device thinner, and it also has the disadvantage that it cannot be used at high temperatures of 80° C. or higher.

In response to this, an absolute magnetic encoder was invented which combined a drum on which a magnetization pattern was written and a magnetoresistive element (Japanese Unexamined Patent Publication No. 118259/1983).

As shown in FIG. 3, at least two rows of magnetization patterns (in this case, magnetization patterns nl"-n4) are provided on the magnetic recording medium 12 formed on the disk II, and each row of magnetization patterns n1xn4 has a magnetic field. Resistance effect element films 13 are arranged, and the absolute value of the rotation angle of the disk 11, that is, the address, can be read by combining the magnetoresistive element films 13 corresponding to each column. The MR element 13 is patterned together with a lead film 15 and a terminal !6 on a single flat substrate 4.The MR element 13 has a length of 2 to 3 mm, a width of 30 μm, and a thickness of 0.05 μm due to heat generation. It is striped, and the lead film 1
5 is a lead terminal i6 from both ends of this MR element stripe.
It is formed of a non-magnetic conductive film such as Cu or AI.

(Problems to be Solved by the Invention) In such a configuration, the substrate 14 used for high resolution (having a magnetization pattern of 12 to 16 rows) needs to have dimensions of about 30 x 50 mm. The distance between this substrate 14 and the magnetic recording medium 12 is kept constant (usually 30 to 50μ).
To keep the board 14 and disk 11 warped and disk 1
It was not put to practical use because it was extremely difficult to achieve due to the surface area of 1 and the backlash of the bearing, and it was easy to break due to contact between the disk +1 and the board 14. Furthermore, since the terminal 16 must be soldered to connect to the external circuit 17, this terminal portion had to be exposed outside the disk diameter. Therefore, there was also a problem in miniaturization.

SUMMARY OF THE INVENTION An object of the present invention is to provide an absolute magnetic encoder that is easy to assemble because it is less likely to be disconnected due to warpage of an MR element substrate or disk, and can be made smaller.

(Means for Solving the Problems) The absolute magnetic encoder of the present invention has at least two magnetic signal tracks arranged concentrically on a disk, and detects the strength of the magnetic field from the magnetization pattern recorded on the tracks. Absolute magnetism, in which a magnetoresistive element film is arranged corresponding to each track, and a change in electrical resistance is detected using a magnetoresistive element formed on a single substrate to read out the absolute value of the rotation angle of the disk, that is, the address. In an encoder, the pattern of the magnetoresistive element film and part of the lead film are on a plane parallel to the disk surface, and most of the lead part and the terminal part are on a plane that is not parallel to the disk surface, or the pattern of the magnetoresistive element is on a plane parallel to the disk surface. It is characterized in that it is patterned on a plane parallel to the disk surface that is further away from the disk surface than the illustrated surface, and that the terminal portion is arranged within the disk diameter.

[Effect]

In this way, only the MR element film pattern constituting the MR element is formed on a substrate surface that is almost parallel to the disk surface, the lead film and the terminal portion are formed on the same substrate on a surface that is not parallel to the disk surface, and the terminal portion is formed on a surface that is not parallel to the disk surface. By arranging it within the disk diameter (the terminal part is at a distance where it does not come into contact with the disk even if soldered), warpage of the MR element substrate and disk and spacing between the MR element substrate and the disk can be kept constant. Disconnection of the MR element pattern due to inability to set is reduced, assembly is facilitated, and miniaturization is also possible.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of the absolute magnetic encoder of the present invention.

This embodiment consists of an aluminum alloy disk 2 fixed to a rotating shaft 1, a Go-P magnetic recording medium 3 formed on the disk surface, and an 8ONi-
The MR element film pattern 5 formed by Felli and Cu
The MR element consists of a lead film 6 formed of a film and a terminal portion 7. The MR element film pattern 5 is on a surface substantially parallel to the disk 2, the lead film 6 and the terminal portion 7 are located at a distance from the disk surface, and the terminal portion 7 is separated from the disk surface by more than ion for soldering. M with such a configuration
When we made 1,000 R elements and assembled a magnetic encoder, the yield rate was 50% due to wire breakage during assembly.
% improved to 90%. This is because in the conventional example, for example, it was necessary to pay attention to the warpage of the entire substrate surface, but in the present invention, it is only necessary to pay attention to the warpage of the MR element film portion.

FIG. 2 is a diagram showing another embodiment of the present invention.

In this embodiment, the terminal portion 7 is patterned on a surface parallel to the disk surface. It is clear that even with this configuration, the same effects as the embodiment shown in FIG. 1 can be obtained.

〔Effect of the invention〕

As explained above, the present invention provides an MR element constituting an MR element.
By forming only the element film pattern on a substrate surface that is approximately parallel to the disk surface, forming the lead film and the terminal portion on a surface that is not parallel to the disk surface on the same substrate, and further arranging the terminal portion within the disk diameter, Assembling is easy, and there is less disconnection of the MR element pattern during magnetic encoder assembly, which is caused by warping of the MR element substrate and disk and the inability to set the spacing between the MR element substrate and disk uniformly. Since it is within the disk size, it has the effect of being miniaturized.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the absolute magnetic encoder of the present invention, FIG. 2 is a perspective view showing another embodiment of the invention, and FIG. 3 is a perspective view showing a conventional example. 1... Rotating shaft, 2... Disc, 3...
- Magnetic recording medium, 4... Glass substrate, 5-MR element film pattern, 6... Lead film, 7... Terminal portion.

Claims (1)

[Scope of Claims] 1. At least two magnetic signal tracks are arranged concentrically on a disk, and a magnetoresistive element film corresponds to each track to adjust the strength of the magnetic field from the magnetization pattern recorded on the tracks. In an absolute magnetic encoder that reads out the absolute value of the rotation angle of the disk, that is, the address, by extracting changes in electrical resistance using a magnetoresistive element formed on a single substrate, the pattern of the magnetoresistive element film is and a part of the lead film is on a surface parallel to the disk surface, and most of the lead portion and the terminal portion are on a surface that is not parallel to the disk surface or further from the disk surface than the surface on which the pattern of the magnetoresistive effect element is drawn. An absolute magnetic encoder characterized by being patterned on a plane parallel to a distant disk surface, and having a terminal portion located within the disk diameter. 2. The absolute magnetic encoder according to claim 1, wherein the magnetoresistive element substrate has a curved shape.