JPH01239414A - Magneto-resistance sensor for magnetic encoder - Google Patents

Abstract

PURPOSE:To enable one magneto-resistance sensor to handle plural magnetic scales by providing different magneto-resistance element patterns together on the same substrate corresponding to the magnetic scaled which differ in recording pitch. CONSTITUTION:Magnetism patterns are recorded on the magnetic scales G1-G3 at different recording pitches lambda1-lambda3, and three different magneto-resistance patterns L1-L3 are formed on the substrate of the magneto-resistance sensor 20 corresponding to the patterns. When the magnetic scale G1 is used, terminals T18 and T19 of the corresponding magneto-resistance element L1 are grounded and a voltage VCC is applied between the terminals T11 and T21 to find the displacement direction and quantity of the scale G1 from the detection signal of a sine wave from a terminal T15 which is generated by the displacement of the scale G1. Other scales G2 and G3 are the same. Consequently, one sensor can be used corresponding to other scales.

Description

Detailed Description of the Invention "Industrial Application Field" This invention is applied to, for example, a magnetic rotary encoder, etc., and is capable of transmitting magnetic information recorded on a magnetic scale to a magnetic scale whose specific resistance changes depending on the strength of the magnetic field. The present invention relates to a magnetoresistive sensor for a magnetic encoder that detects relative displacement of a magnetic scale by detecting it using a resistance element.

``Prior Art'' As is well known, a magnetic rotary encoder consists of a magnetic scale formed on a magnetic recording medium fixed to a shaft, and a magnetic resistor placed opposite the magnetic scale with a predetermined gap. It consists of a sensor.

FIG. 2 shows the configuration of a magnetic scale and a magnetoresistive sensor in a conventional magnetic rotary encoder. In this figure, 1 is a magnetic scale and 2 is a magnetoresistive sensor. This magnetic scale l is formed by recording sinusoidal magnetic information (magnetization pattern) at a recording pitch λ on a circular orbit centered on the shaft of the magnetic recording medium.

On the other hand, the magnetoresistive sensor 2 includes a glass substrate 3 and a magnetoresistive element pattern 4 that is patterned after being deposited on the glass substrate 3. This magnetoresistive element pattern 4 is made of an element material that produces a so-called magnetoresistive effect, a phenomenon in which the specific resistance changes depending on the strength of the magnetic field when placed in a magnetic field. When the magnetic scale 1 is relatively displaced in the direction of the arrow M shown in the figure, the magnetization pattern recorded on the magnetic scale I is read, and thereby the magnetic scale! The amount of rotation of the shaft that rotates together with the shaft is detected.

In this case, the magnetoresistive element pattern 4 is the magnetic scale 1
Detecting portions S, ~S8 extending in a direction perpendicular to the displacement direction M of
and connecting portions 01 to C7 that connect the detection portions S and S8 to each other and extend parallel to the displacement direction M, and are formed in a comb shape.

Here, each of the detection units 81 to S8 is arranged in accordance with the recording pitch λ of the magnetization pattern in the magnetic scale 1. That is, the detection unit S is separated by λ from the detection unit S8, the detection unit S3 is separated by λ/2 from the detection unit S, the detection unit S4 is separated by λ from the detection unit S3, and the detection unit S5 is separated by λ from the detection unit S4. λ/4
The detection unit S8 is separated from the detection unit S5 by λ, and the detection unit S8 is separated from the detection unit S5 by λ.
7 is spaced apart from the detection part S6 by λ/2, and the detection part S8 is separated from the detection part S
7 and λ apart. Furthermore, the end of the detection section S1 is connected to a terminal T.
1, the connection C7 is connected to the terminal 'r, and the connection C4 is connected to the terminal T.
3, the connecting portion C6 is connected to the terminal T4, and the end of the detecting portion S8 is connected to the terminal 'r.

Then, by grounding the terminal 'r3, +V is applied to the terminals T1 and T.
When cc is applied, along with the displacement of the magnetic scale I, a sine wave detection signal S ino U T is output from the terminal 'F2, and a cosine wave detection signal Co5 is output from the terminal T4.
0UT is output. As a result, these detection signals S
Based on inoUT and Co50UT; first, the direction and amount of displacement of the magnetic scale 1 are determined.

``Invention or problem to be solved'' By the way, in the conventional magnetoresistive sensor for a magnetic encoder described above, magnetoresistive elements are arranged on one dam plate in accordance with the recording bits of one type of magnetic scale. ,1
There was a problem in that it could only be used with magnetic scales for different types of recording pinches, and that it could not be used in combination with magnetic scales for other recording pinches.

This invention was made in view of the above-mentioned circumstances, so 1g
The purpose of the present invention is to provide a magnetoresistive sensor for a magnetic encoder that can be used in combination with many types of magnetic scales.

"Means for Solving the Problems" This invention provides a magnetoresistive element pattern that is disposed facing a magnetic scale on which magnetic information is recorded at a predetermined pitch, and a magnetoresistive element pattern that corresponds to the recording pitch of the magnetic information is formed on a substrate. This magnetoresistive sensor for a magnetic encoder is characterized in that a plurality of magnetoresistive element patterns each corresponding to a magnetic scale having a different recording pitch of magnetic information are mixed on the same substrate.

[Operation J] According to the above configuration, by selecting and using a magnetoresistive element pattern corresponding to the magnetic scales to be used in combination, it can be used as a magnetoresistive sensor compatible with a plurality of magnetic scales.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. 2
0 is a magnetoresistive sensor, and magnetoresistive element patterns L1 to L3 are formed on a substrate (not shown). 61～
G3 is a magnetic scale that can be used in combination with this magnetoresistive sensor 20. The magnetic scale G1 has a recording pitch of λ1, the magnetic scale G2 has a recording pitch of λ3, and the magnetic scale G3 has a magnetized pattern at a recording pitch of ^3. recorded. Next, magnetoresistive element patterns L1 to L
3 will be explained. Ll is a magnetic resistance element pattern corresponding to the magnetic scale G1, and the detection portions S II to S
It has ea. L, is v corresponding to the magnetic scale G2
t With magnetoresistive element pattern, detection section 821 to S2+1
has. L3 is a magnetic resistance element pattern corresponding to the magnetic scale G3, and the detection part S31'''-538 is the same.

Kokote, detection section Sll ~ S + 8, S 21 ~ S 2Rs
S31~S:lIl is magnetic scale G11G7, G
It is formed to extend in a direction perpendicular to the displacement direction xi of No. 3.

Then, the detection part S I+""'S18 is the magnetic scale G
1, the detection unit 9
21 to S28 are arranged to correspond to the recording pitch λ of the magnetized pattern on the magnetic scale G, and the detection parts S31 to S5311 are arranged to correspond to the recording pitch λ3 of the magnetized pattern on the magnetic scale G3. That is, the detection unit S
at is located between the detection unit S L+ and λ1M, and the detection unit S 13 is spaced apart from the detection unit S I2 by λl/2;

4 is spaced apart from the detection part S13 by λ1, detection part S15 is spaced from the detection part S+4 by (m+1/4)λ+ (m is an integer), and detection part S18 is spaced from the detection part S15 by λ1M. The section SI7 is spaced apart from the detection section S Ill by λ1/2, and the detection section S+8 is spaced apart from the detection section S17 by λ. Similarly, the detection units S, -S.

8 corresponds to the recording pitch λ, and the detection units S31 to S3B correspond to the recording pitch λ3, respectively. Note that the detection section S13 of the magnetoresistive element pattern -L and the detection section St5 of the magnetoresistive element pattern L share the same pattern. Then, each detection unit Sll to S
Terminals T1 and Tt7 are formed at the ends of III, S2+-5zs, and S31 to S3B.

Next, how to use this magnetoresistive sensor 20 will be explained. First, when G1 is used as a magnetic scale, the magnetoresistive element pattern L is used as a pattern for a magnetoresistive sensor. That is, the terminal 'r+a, T19 is grounded, and the power supply voltage Vcc is applied to the terminal TIt, T2+. In this way, a sine wave detection signal is output from the terminal T+5 in accordance with the displacement of the magnetic scale G1.
A cosine wave detection signal is output from the terminal T20. Thereby, the direction and amount of displacement of the magnetic scale G can be determined from these sine wave and cosine wave detection signals. Next, when using G as a magnetic scale,
The magnetoresistive element pattern L is used as a pattern for a magnetoresistive sensor. That is, the terminals TI4 and TI5 are grounded, and the power supply voltage Vcc is applied to the terminals TIt and TI7.

In this way, along with the displacement of the magnetic scale G2,
A sine wave detection signal is output from the terminal T13, and the terminal T
18 outputs a cosine wave detection signal. When G3 is used as the magnetic scale, the magnetoresistive element pattern L3 is used as the magnetoresistive sensor pattern.

That is, the terminals T24 and Tts are grounded, and the terminals Tty and Tts are grounded.
Power supply voltage Vcc is applied to Ttt. In this way, as the magnetic scale G3 is displaced, a sine wave detection signal is output from the terminal '13, and a cosine wave detection signal is output from the terminal Tt6.

"Effects of the Invention" As explained above, according to the present invention, a plurality of magnetoresistive element patterns each corresponding to a different magnetic scale of recording pitch of magnetic information are mixed on the same substrate.
This provides the advantage that a single magnetoresistive sensor can be used as a magnetic sensor compatible with multiple magnetic scales.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetoresistive sensor for a magnetic encoder and a magnetic scale according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional magnetoresistive sensor for a magnetic encoder and a magnetic scale. Gl, G2, G3...Magnetic scale, 20...
... Magnetoresistive sensor, L-2, L3... Magnetoresistive element pattern.

Claims (1)

[Claims] In a magnetoresistive sensor for a magnetic encoder, which is arranged opposite to a magnetic scale on which magnetic information is recorded at a predetermined pitch, and a magnetoresistive element pattern corresponding to the recording pitch of the magnetic information is formed on a substrate, each magnetic A magnetoresistive sensor for a magnetic encoder, characterized in that a plurality of magnetoresistive element patterns corresponding to magnetic scales with different information recording pitches are mixed on the same substrate.