JPS61151819A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To attain the effective use of a magnetic flux flowing through a magnetic core by arraying the coil conductors crossing the magnetic core in an approximately symmetrical form to a magnetic gap. CONSTITUTION:A lower insulated layer 2, coil strokes 3a-3d, an upper insulated film 4 and upper cores 5a and 5b made of a thin film of a soft magnetic matter like a lower core 1 are laminated on this core 1. Thus a magnetic head is obtained. A nonmagnetic thin film is held between cores 5a and 5b for formation of a magnetic gap 6. The coil windings 3a-3d passing through a ring consisting of those cores 1, 5a and 5b are arrayed symmetrically to the gap 6. Then it is possible to distribute the strokes 3a-3d at positions near the flow-in point of a magnetic flux. Thus the induced voltage of each stroke can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a thin film magnetic head suitable for high-density magnetic recording of VTRs, magnetic disks, and the like.

[Background of the Invention] A magnetic head in which soft magnetic thin film core materials such as permalloy are laminated with a minute gap between them, the end face of the core material serves as a sliding surface against a recording medium, and the minute gap is used as a magnetic gap. is proposed. However, as pointed out in Japanese Patent Laid-Open No. 157121/1982, this type of head has the disadvantage of poor electromagnetic conversion efficiency. In order to solve this problem, Japanese Patent Laid-Open Publications No. 55-132519 and No. 58-137121 propose a magnetic head in which the surface of a soft magnetic thin film is used as a sliding surface.

However, in both cases, only a single turn coil was considered, and since the reproduced output was small, it was necessary to increase the gain of the amplifier circuit.

Further, in the case of a one-turn coil, there are problems such as the inability to cancel the voltage induced by an external magnetic field and the possibility of receiving induced noise. OBJECTS OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a thin film magnetic head that can obtain high output by winding a coil a large number of times.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized in that the coil conductors that cross the magnetic core are arranged approximately symmetrically with respect to the magnetic gap to effectively utilize the magnetic flux flowing through the core.

[Embodiments of the invention]

Embodiments of the thin film magnetic head according to the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a thin film magnetic head of the present invention. The wire of the coil has a cross section. A lower insulating layer 2, coil wire elements 3α to 5d, on a lower core 1 made of a thin film of soft magnetic material,
An upper insulating film 4, an upper core 5α which is a thin film like the lower core,
The head is constructed by laminating 5A. A thin film of non-magnetic material is sandwiched between the upper cores 5α and 56 to form a magnetic gap 6.
I have to. The sliding surface with the magnetic medium is the upper core 5α.

5b. FIG. 2 is a view of the head shown in FIG. 1 viewed from the sliding motion side, in which a four-turn thin film coil is formed. Lower core 1, upper core 5α.

Coil wire elements 3α to 3cL passing through the ring consisting of 5b
are arranged symmetrically with respect to the magnetic gap 6.

FIG. 3 is a diagram showing the voltage induced in each wire element of the coil during reproduction. In the conventional example of the structure shown in (α), the end face of the core at the left end of the drawing becomes a sliding surface, and as shown in F) and (b)), the induced voltage decreases in the wire element far from the magnetic gap 6. are doing. The reason for this is that the magnetic flux flowing into the magnetic gap 6 from the magnetic medium (not shown) passes between the lower core 1 and the upper core 6 before reaching the rear gap 7, which is the original magnetic circuit.
This is because the amount of magnetic flux associated with the coil wire element far from the gap decreases due to leakage on the opposing surface of the gap.

On the other hand, in the structure C) of the present invention, it is possible to arrange the coil wire elements in a concentrated manner near the inflow point of the magnetic flux, so that the induced voltage of each wire element can be increased. As for the induced voltage of each line element, as shown in (d), line elements 5b and 50 are equidistant from magnetic gap 6, and the same voltage is obtained, and line elements 5a and 5d also have the same voltage.

FIG. 4 is a diagram of another embodiment of the present invention viewed from the sliding surface side.
The entire coil is arranged approximately symmetrically with respect to the magnetic gap 6. In this configuration, for the magnetic flux that flows in from the magnetic gap 6 and circulates through the magnetic core, an in-phase voltage is generated in each coil and the coils are connected in series. The left and right coils generate voltages with opposite phases and cancel each other out against the magnetic flux flowing into the coil.

In other words, it is possible to create a magnetic head that is less susceptible to induced noise from the outside. In the coil having the configuration shown in FIG. 4, the number of coil wire elements crossing the core is limited to an even number.

〔Effect of the invention〕

As described above, in the present invention, a large reproduction output can be obtained in the thin-film magnetic head by providing a large number of coils and effectively using the magnetic flux flowing from the magnetic medium into the magnetic gap. Further, if the structure shown in FIG. 4 is adopted, in addition to the above-mentioned advantages, there is also the effect of making the structure less susceptible to external induced noise.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
FIG. 5 is a detailed explanatory diagram of the present invention, and FIG. 4 is a plan view showing another embodiment of the present invention. 1... Lower core, 2... Lower insulating film, 3α
, 5b, 5e, 5d-... Coil wire element, 4
...Top insulating film, 5α, 5b...Top core,
6... Magnetic gap, 7... Rear gap, 8
...Coil terminal. Figure 1 Figure 2 Figure 3 (α) (C) Line element i fL

Claims (1)

[Claims] 1. A lower core made of a magnetic thin film, a conductor coil wire element, an insulating layer surrounding the conductor coil wire element, and an upper core are laminated on the substrate, and the upper core is divided into gaps made of a non-magnetic material. 1. A thin film magnetic head having a thin film magnetic head using the upper surface of the upper core as a sliding surface, characterized in that thin film conductor coil wire elements are arranged substantially plane symmetrically with respect to the gap surface.