JPH0833308B2 - Magnetic sensor and manufacturing method thereof - Google Patents

Description

The present invention relates to a magnetic sensor and a method for manufacturing the same, and in particular, a magnetic sensor in which a magnetoresistive effect element is arranged in a radial direction facing a rotor magnetized in the circumferential direction. And its manufacturing method.

[Conventional technology]

The magnetoresistive effect element (hereinafter referred to as "MR element") is a Ni-
With Fe, Ni-Co, etc., the change in applied magnetic field can be detected by the change in resistance of the thin film element. Therefore, if a permanent magnet or the like is used as a magnetic field generating means, a light source such as an LED (light emitting diode) is required, and a light source that can be consumed is more important than a photosensor or the like.
A sensor having a simple structure and excellent durability can be obtained.

The magnetic anisotropy of the MR element can be formed by the oblique incidence effect during film formation, the external magnetic field and the shape. Therefore, it is easy to make the flow of the magnetic flux generated from the magnetization pattern recorded on the rotor, which is the object to be detected, and the direction of magnetic anisotropy of the MR element orthogonal to each other. Since the resistance change rate of the element is maximized, the resistance change at this time is converted into a signal and used for control such as rotation speed and position detection.

Conventionally, as one of the utilization methods, there is a VTR (video tape recorder) capstan motor, which faces a rotor magnetized in the circumferential direction and is mounted on a substrate 1 as shown in a plan view of FIG. There is provided a magnetic sensor in which MR elements 2 are radially arranged in a radial direction, and the MR elements 2 have a magnetic anisotropy direction 3 in a fixed direction. In addition, 4 is an electrode.

This is an integral type magnetic sensor that detects the magnetizing unevenness and deformation of the rotor with high accuracy by integrating the output of the MR element 2. The manufacturing method of the MR element 2 for sensor is a substrate such as glass. A method of obtaining an element having magnetic anisotropy in a certain direction by vapor deposition while applying a magnetic field from the outside has been adopted.

[Problems to be solved by the invention]

However, in the above-mentioned conventional example, as shown in FIG. 4, since the longitudinal direction of the MR element pattern and the magnetic anisotropy direction are different, there is a problem that sufficient characteristics cannot be obtained for use as a sensor. .

FIG. 5 shows the RH characteristics when the angle θ formed by the longitudinal direction of the MR element pattern and the magnetic anisotropy direction is changed from 0 to 90 degrees. The angle θ is 90 degrees. The rate of change in resistance and the occurrence of hysteresis are occurring as
These cause a malfunction of the sensor and are problems that must be solved.

The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a surface-opposed magnetic sensor capable of extremely highly accurate position detection / control.

[Means for solving problems]

The present invention aims to improve the characteristics of the surface-opposed magnetic sensor by forming the magnetic anisotropy of the MR element in the radial direction so as to face the rotor magnetized in the circumferential direction.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A first showing a front view of a face-to-face magnetic sensor according to the present invention
In the figure, 1 is a substrate, 2 is an MR element radially arranged on the surface of the substrate, and a MR film is formed using a vacuum thin film forming technique using Ni-Co, Ni-Fe, etc. It is obtained by forming a zigzag pattern along concentric circles by an etching technique. Reference numeral 13 denotes the magnetic anisotropy direction of the MR element 2, which is radially formed from the center of the concentric circle in a radial direction. A method for forming the same will be described below.

In FIG. 2 showing the manufacturing process of the magnetic sensor according to the present invention by a vertical cross-sectional view, in forming the MR film 12 on the substrate 1 of FIG.
A magnetic field generation source 5 that radially generates a magnetic field is installed on the back side of the substrate 1. According to this method, radial magnetic anisotropy is formed in the radial direction without being affected by the magnetic anisotropy formed by the incidence effect and the shape effect during film formation.

Then, a zigzag pattern of the MR element 2 is formed by the etching technique as shown in FIG.
(See also FIG. 1) Another embodiment of the manufacturing method is shown in the process diagram of FIG. This is because, as shown in FIG. 2F, after the MR film 12 is formed on the substrate 1 in FIG.
The substrate 1 is a magnetic field generation source 5 that generates a radial magnetic field in the radial direction.
If it is placed on the back side of the MR film or on the front side of the MR film 12 and subjected to heat treatment in vacuum, radial magnetic anisotropy can be formed in the longitudinal direction of the MR film 12. FIG. 6G is a completed view of the magnetic sensor.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention is directed to the MR extending in the radial direction.
Since the element pattern is formed and its magnetic anisotropy is given in the radial direction, when it is used in a face-to-face type magnetic sensor, a significant improvement in performance can be obtained compared to the conventional magnetic sensor, and extremely highly accurate position detection The effect is that it can be controlled.

[Brief description of drawings]

FIG. 1 is a front view of a face-to-face magnetic sensor embodying the present invention, FIG. 2 is a manufacturing process diagram similarly shown by a longitudinal sectional view, FIG. 1A is a diagram of a substrate, and FIG. Is the figure at the time of film formation,
FIG. 3C is a completed drawing after etching, FIG. 3 is a process drawing of another embodiment of the same manufacturing method, FIG. 3D is a drawing of the substrate, and FIG. The figure, (f) is the figure during heat treatment, (g) is the completed figure after etching,
FIG. 5 is a front view of a conventional magnetic sensor, and FIG. 5 is a graph showing the relationship between the angle formed by the MR element pattern longitudinal direction and the anisotropic direction and the RH characteristic. 2 ... Magnetoresistive element 5 ... Radial magnetic field source 12 ... Magnetoresistive film 13 ... Radial magnetic anisotropy of magnetoresistive element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Nakahashi 1248 Shimokage Mori, Chichibu City, Saitama Prefecture, Canon Electronics Co., Ltd. (72) Inventor Hideto Sano 1248 Shimokagemori, Chichibu, Saitama Prefecture Canon Electronics Co., Ltd. (56) Reference JP-A-63-212805 (JP, A) JP-A-62-220809 (JP, A) ) JP-A-59-7213 (JP, A)

Claims (3)

[Claims] 1. A magnetic sensor in which a magnetoresistive effect element is arranged in the radial direction so as to face a rotor magnetized in the circumferential direction, and the magnetic anisotropy of the magnetoresistive effect element is the radial direction. A magnetic sensor characterized by being attached to a magnetic sensor. 2. A magnetic sensor in which magnetoresistive elements are radially arranged facing a rotor magnetized in the circumferential direction, and when a magnetoresistive film is formed, a radial magnetic field is generated. A method of manufacturing a magnetic sensor, characterized in that a magnetic anisotropy is imparted in a radial direction by using a magnetic field generating source. 3. A magnetic sensor having a magnetoresistive effect element radially arranged facing a rotor magnetized in the circumferential direction, wherein a magnetic field is generated in the radial direction after a magnetoresistive effect film is formed. A method of manufacturing a magnetic sensor, characterized in that magnetic anisotropy is imparted in a radial direction by heat treatment using a magnetic field source.