JPH047816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Scope of the Invention] The present invention relates to a magnetic flux responsive multi-gap head for detecting the magnetization pattern of a magnetic scale and converting it into an electrical signal.

[Technical background of the invention]

The magnetic flux responsive multi-gear head has been developed and put into practical use in order to obtain high accuracy, high resolution, and stable high output when detecting the magnetization pattern on the magnetic scale and electrically reading the length and angle. n heads are arranged with a gap of λm/2 (λm is the characteristic wavelength of the multi-gap head), and all are connected in series with adjacent heads facing in opposite directions. The outputs of each head are then added together, and when the characteristic wavelength λm of the multi-gap head matches the wavelength λ of the magnetic scale, the output reaches its maximum, and the output is n times that of a single head. It is becoming possible to obtain Conversely, if the wavelength λ of the magnetic scale and the characteristic wavelength of the multi-gap head do not match, a phase difference will occur in the output of each head and the output will be attenuated.

Such a magnetic flux responsive multi-geap head conventionally has a core made of a thin plate of high magnetic permeability material (e.g. permalloy), and thin plates of non-magnetic material (e.g. beryllium copper) used as separators, stacked alternately, and each core has one core. It was constructed with two gaps.
And the gap distance is minute, for example 0.1mm,
Since this gap variation has a large effect on the characteristic wavelength of the multi-gap head, conventionally the thickness of the laminated metal plates of high magnetic permeability material and non-magnetic material is defined within a certain range. I try to maintain the gap spacing. For example, if the gap spacing mentioned above is set to 0.1 mm, the thickness of the thin plate core made of high magnetic permeability material (permalloy) and the thin plate separator made of non-magnetic material (beryllium copper) must be precisely specified to 0.05 mm. gap is not formed.
Furthermore, since the lamination must be carried out while paying careful attention to the thickness, much labor is required and manufacturing of the magnetic flux responsive multi-gap head becomes troublesome.

[Purpose of the invention]

This invention was made based on the above-mentioned circumstances, and its purpose is to develop a magnetic flux-responsive multi-gap device that does not use high magnetic permeability and non-magnetic metal plates that require strict thickness regulations. The purpose is to provide a head.

[Summary of the invention]

This invention provides a metal plate or a ceramic substrate with a non-magnetic thin film layer having a thickness of 1/4λ of the recording wavelength λ of a magnetic scale and a high magnetic permeability magnetic thin film layer alternately by sputtering or vapor deposition. A magnetic flux-responsive multi-gap head having a plurality of the above-mentioned thin film layers and having an accurate gap gap is constructed.

[Embodiments of the invention]

The present invention will be described below based on embodiments shown in the drawings. As shown in FIG. 1, the magnetic flux responsive multi-gap head of the present invention has a thin film layer of a high permeability magnetic material (permalloy) on the surface of a substrate 1 made of metal or ceramic in the shape of a multi-gap head. 2 is deposited using a vacuum evaporation apparatus to a thickness of 1/4λ of the recording wavelength λ of the magnetic scale, and then a thin film layer 3 of a nonmagnetic material (beryllium copper) is deposited at a thickness of 1/4λ of the recording wavelength λ of the magnetic scale. The second step was repeated by repeating the steps of vapor deposition to a thickness of 4λ and further vapor depositing a high permeability magnetic thin film layer 2 to the same thickness.
As shown in the figure, high permeability magnetic thin films 2 and nonmagnetic thin films 3 are alternately deposited and laminated.

High magnetic permeability magnetic thin film 2 and non-magnetic thin film 3 are approximately 3
Since the thickness of the deposited film that is deposited in one go by vacuum evaporation is several tens of micrometers, if the gap interval is 0.1 mm, the high permeability magnetic thin film 2 and the Since the thickness of each magnetic thin film 3 is required to be 0.05 mm, one layer is deposited several times to form a layer having the required thickness. In this case, if the film thickness by vapor deposition is experimentally determined in advance using a measuring device for one vapor deposition, the film thickness can be accurately and easily controlled by the number of vapor depositions.

〔Effect of the invention〕

As explained above, the present invention constitutes a magnetic flux responsive multi-gap head in which thin films of high permeability magnetic material and thin films of non-magnetic material are alternately formed on a base material by sputtering or vacuum deposition. Therefore, it is extremely easy to control the thickness of each of these thin film layers, and it is possible to obtain a more accurate thickness compared to the conventional lamination of metal plates made of high magnetic permeability material and non-magnetic material. A magnetic flux-responsive multi-gap head with less fluctuation can be obtained. Furthermore, since each thin film layer to be laminated is formed using a sputtering device or a vacuum evaporation device as described above, it is possible to easily laminate any number of thin film layers of a constant thickness by setting the conditions first. This has excellent effects such as facilitating the manufacture of magnetic flux responsive multi-gap heads.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of an embodiment of the invention, and FIG. 2 is a schematic cross-sectional view as well. DESCRIPTION OF SYMBOLS 1...Substrate, 2...High permeability magnetic thin film layer, 3...Nonmagnetic thin film layer.

Claims (1)

[Claims] 1. In a magnetic flux-responsive multi-gap head that detects a magnetic grating made by magnetically recording a signal of a certain wavelength on a magnetic medium, the recording wavelength λ of the magnetic scale is 1/1/2 of the recording wavelength λ by sputtering or vapor deposition on the substrate.
A high permeability magnetic thin film layer with a thickness of 4λ is provided, and a nonmagnetic thin film layer with a thickness of 1/4λ of the recording wavelength λ of the magnetic scale is provided on it by sputtering or vapor deposition. A magnetic flux-responsive multi-gear head characterized by having multiple alternating layers.