JPS6196408A - Magnetic flux response type multi-gap head - Google Patents

Abstract

PURPOSE:To loosen the regulation of the thickness of a highly permeable material and a nonmagnetic material by forming a nonmagnetic thin film layer of which thickness is 1/4 the recording wavelength of a magnetic scale formed on a substrate on a highly permeable magnetic thin film layer having the same thickness and then forming both the layers alternately. CONSTITUTION:The thin film layer 2 consisting of the highly permeable magnetic substance is formed on the surface of the multi-gap head-shaped substrate 1 by sputtering or vapor deposition and the thin film layer 3 consisting of the nonmagnetic substance is formed on the surface of the layer 2 by sputtering or vapor deposition. These layers 2, 3 are alternately laminated plural times and each thickness of the layers 2, 3 is set up to 1/4 the recording wavelength lambdaof the magnetic scale.

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 a magnetization pattern of a magnetic scale and converting it into an electrical signal.

[Technical background of the invention]

A magnetic flux-responsive multi-gap head developed and put into practical use to obtain high nitration, high resolution, and stable high output when detecting magnetization and equal turns on a magnetic scale and reading the length and angle t electrically. is λm/2(λ
m is arranged in the multi-gap with a gap of d's characteristic wavelength), and adjacent heads are all connected in series with opposite directions. The outputs of each head are then added together, and the output reaches its maximum when the multi-gap head's natural wavelength λm matches the wavelength λ of the magnetic scale, resulting in an output n times that of a single head. It is now possible to

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, resulting in attenuation of the output.

Such magnetic flux-responsive multi-gap heads conventionally have a core made of a thin plate of high magnetic permeability material (for example, Ya-Malloy).
Thin plates of non-magnetic material (eg, copper) were stacked alternately as cellulators, with each core having one gap. The gap between the gears and the gears is as small as 0.1 m, for example, and fluctuations in this gap have a large effect on the characteristic wavelength of the multi-gap head. The thickness of the metal plate is defined within a certain range to maintain the gap distance.

For example, when the above-mentioned gap interval is set to 0.1 m, the plate thickness of the thin plate core made of high magnetic permeability material (NOKUMAROY) and the thin plate separator made of non-magnetic material (beryllium steel) is 0.0 m.
If the distance is not precisely specified to 5 m, the above gears and pulls will not be formed. Furthermore, since the lamination must be carried out while paying careful attention to the thickness, much labor is required and the preparation of the magnetic flux responsive multi-gap head becomes troublesome.

[Purpose of the invention]

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

[Summary of the invention]

In this invention, a non-magnetic thin film layer having a thickness of 1/4 λ of the recording wavelength λ of a magnetic scale and a high permeability magnetic thin film layer are alternately deposited on a metal plate or a ceramic substrate by spooling or vapor deposition. A magnetic flux-responsive multi-gap structure having a plurality of precursor thin film layers each having a precise gap gap is constructed by forming a multi-gap structure.

[Embodiments of the invention]

The present invention will be described below based on embodiments shown in the drawings. The magnetic flux response type multi-gear, dehe, de of this invention is the first
As shown in the figure, a thin film layer 2 of a high magnetic permeability magnetic material (permalloy) is deposited on the surface of a substrate 1 made of metal or ceramic in the shape of a multi-gap head using a vacuum evaporation device. Next, a thin film layer 3 of a non-magnetic material (copper) is formed by vapor deposition to a thickness of 1/4λ of the recording wavelength λ of the magnetic scale, and then a high magnetic permeability thin film layer 3 is formed. The high permeability magnetic thin film 2 and the nonmagnetic thin film 3 are alternately deposited and laminated as shown in FIG.

Approximately 30 layers of the high permeability magnetic thin film 2 and the nonmagnetic thin film 3 are stacked, and since the thickness of the deposited film formed at one time by vacuum evaporation is generally several tens of μm, the gap interval is set to 0.1 am. In this case, high permeability magnetic thin film 2
Since each of the non-magnetic thin films 3 and 3 needs to have a thickness of 0.05 m, 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, in order to configure a magnetic flux-responsive multi-gap head, the present invention is capable of forming a thin film of a high magnetic permeability magnetic material and a thin film of a non-magnetic material alternately on a base material by threading, sintering, or vacuum evaporation. Therefore, it is extremely easy to control the thickness of each of these thin film layers, and a more accurate thickness can be obtained 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 gear and gap fluctuation can be obtained. Also,
Each thin film layer to be laminated is formed by a slender, taring device, or vacuum evaporation device as described above, so if conditions are set first, any number of thin film layers of a constant thickness can be easily laminated. This has excellent effects such as facilitating the manufacture of magnetic flux responsive multi-gap heads.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an embodiment of the invention, and FIG. 2 is a schematic cross-sectional view as well. 1...Substrate, 2...High permeability magnetic thin film layer, 3...
・Non-magnetic thin film layer. Figure 1 Figure 2

Claims (1)

[Claims] 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, a highly transparent film with a thickness of 1/4 λ of the recording wavelength λ of the magnetic scale is formed on the substrate by sputtering or vapor deposition. A magnetic thin film layer is provided, and a magnetic scale recording wavelength λ of 1
1. A magnetic flux responsive multi-gap head characterized in that a non-magnetic thin film layer with a thickness of /4λ is provided by sputtering or vapor deposition, and a plurality of these thin film layers are alternately formed.