JPH02201712A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve recording and reproducing characteristics in a high-frequency region by removing the work affected layers of at least either of the track width regulating grooves in which a nonmagnetic material is molded and the outer peripheral surface of the magnetic head. CONSTITUTION:The work affected layers are formed by mechanical finishing, such as cutting and polishing, on the surfaces of the track width regulating grooves 18, 18a of core half bodies 2, 2a constituting the magnetic head and the outer peripheral surface of the magnetic head. Crystal lattices are disturbed and magnetic characteristics are deteriorated in the work affected layers. The core half body blocks 2, 2a are, therefore, immersed into hydrochloric acid, hot concd. phosphoric acid, etc., and are etched to remove the work affected layers formed in the track width regulating grooves 18, 18a. The high recording and reproducing characteristics in a high-frequency region are obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head used in a video tape recorder (VTR) or the like. It is an object of the present invention to provide a magnetic head with improved recording and reproducing characteristics in a high frequency region by removing the process-affected layer of the core half of the magnetic head.

(Prior Art) FIG. 5 is a diagram for explaining a manufacturing process for manufacturing a conventional magnetic head (ferrite head) for a VTR.

In the figure, ■ indicates a polishing process, in which a pair of rectangular parallelepiped core half blocks 2 become the core halves of the magnetic head.
(2a) is prepared, and this core half block 2 (2a>
Mirror-polish the top surface (the surface that will be the gap butting surface) with an abrasive.

(2) indicates a groove machining process, in which winding grooves 4a are formed in the gap abutting surface of at least one of the core half blocks 2 polished in the polishing process (2), and if necessary, Winding guide groove 4 on the outer surface of block 2 (2'a)
b are formed along the elongated direction shown by arrow A, respectively.

3 shows the track width regulating groove machining process, in which one core half block 2 and the other core half block 2a are
Track width regulating grooves 8 and 8a are formed, respectively.

3 shows the step of attaching the gap spacer material and adhesive glass to the front gap portion 6a of the gap abutting surface of at least one core half block 2 formed in the track width regulating groove forming step 2. , for example 5i0
A gap spacer material such as No. 2 is attached by sputtering or the like.

Furthermore, adhesive glass is also attached to the pack gap portion 6b by sputtering or the like.

(2) shows a butt-joining step, in which the gap abutting surfaces of the core half blocks 2, 2a are tracked and butted together. Then, glass is molded into the track width regulating groove formed by the groove 88a, and at the same time, both core half blocks 2.degree. 2a are butt-joined to form the core half block 9.

(2) indicates a core slicing step, in which the core body block 9 obtained in the butt joining step (2) is sliced into a predetermined thickness at a predetermined azimuth angle α as shown by the broken line.

(2) is a magnetic head completed by slicing in the core slicing process (2).

(Problem to be Solved by the Invention) In recent years, the performance of magnetic tapes and magnetic heads has improved significantly, and high-quality VTRs with higher resolutions, with horizontal resolutions of 400 lines or more, are now available. It is about to appear. This high image quality VTR was made possible by significantly shifting the conventional carrier frequency to the higher frequency side and further improving short wavelength recording and reproducing characteristics. For heads, it has been desired to improve reproduction characteristics in higher frequency ranges.

However, magnetic heads obtained by the conventional manufacturing method as described above cannot fully satisfy these demands.

The present invention was made in order to solve this problem, and an object of the present invention is to obtain a magnetic head that can obtain high reproduction characteristics in a higher frequency region.

(Means for solving problems) The inventors have conducted various experiments regarding magnetic heads.

As a result, it was found that the reproduction characteristics of the magnetic head in the high frequency range are greatly influenced by the process-affected layer formed on the surface of the track width regulating groove of the core half of the magnetic head and on the outer peripheral surface of the magnetic head. I found it. The process-altered layer is
It is formed by mechanical processing such as cutting and polishing. In the process-affected layer, the crystal lattice is disturbed and the magnetic properties are deteriorated. Particularly in high Bs (saturation magnetic flux density) ferrite materials, the degree of this deterioration is large.

The magnetic flux generated in the magnetic head passes through the outer peripheral surface of the head.

At the sliding contact surface 10a with the magnetic tape, as shown in FIG. 6, the magnetic flux passes through the gap along the track width regulating groove 8.8a. (In the figure, 11 is the glass molded into the grooves 8 and 8a.) Therefore, if a process-affected layer is formed on the track width regulating groove and the outer peripheral surface of the head, the magnetic flux will be disturbed, and this will cause the high frequency of the magnetic head to This caused the characteristics in the area to deteriorate.

Therefore, the present invention provides a magnetic head made by abutting two core halves made of ferrite, the track width regulating groove in which a non-magnetic material is molded, and a process-affected layer on at least one of the outer peripheral surface of the magnetic head. The present invention provides a magnetic head characterized in that the .

(Example) The magnetic head according to the present invention will be explained by way of examples.

FIG. 1 is an external view of a first embodiment of a magnetic head according to the present invention, and FIG. 2 is a diagram for explaining the manufacturing process thereof.

The same parts as in the conventional example are given the same reference numerals, and detailed explanations of those parts will be omitted.

In the embodiment shown in FIG. 1, the track width regulating groove 18° 18a
The process-altered layer has been removed. In the figure, 2.2a is a core half block (ferrite material), 4a is a winding groove, 4
b is a winding guide groove, 10 is a sliding contact surface with the magnetic tape, 11
is glass molded into the track width regulating groove 18°18a.

Next, the manufacturing process will be explained. In order to obtain the magnetic head of this embodiment, a step (2) of etching track width regulating grooves and a step (2) of lapping the abutting surfaces are performed between the conventional process (1) and (2) shown in FIG. will be established. (See FIG. 2) In step (2), the core half blocks 2, 2a are immersed in hydrochloric acid, hot phosphoric acid, etc. and etched to remove the damaged layer formed in the track width regulating grooves 18, 18a. At this time, the process-affected layer formed on other parts of the core half block 2.2a is also removed.

In step (2), each abutting surface 19.
19a is lapped by float polishing or the like.

As a result, a regular track width (about several tens of microns) can be obtained.

Now, by wrapping the butt surface 19.1
A new process-affected layer is formed in 9a, albeit slightly. However, this process-affected layer is a very thin layer formed on the surface from which the process-affected layer was removed in the -degree process (1), and has almost no effect on the magnetic properties.

In addition, in step (2), the track width regulating groove 18°18a
If the abutting surfaces are masked so that only the etched portion is etched, step (2) is not necessary.

After completing step (2), a magnetic head is obtained in the same manner as in the conventional example.

Next, a second example will be described. In this embodiment, the damaged layer of the track width regulating groove is not removed, but the damaged layer of the outer peripheral surface of the magnetic head is removed. The manufacturing method does not include the above steps ■ and ■, but uses the conventional slicing process ■
After that, an etching process is performed in which the cut out magnetic head is immersed in hydrochloric acid. As a result, the process-affected layer on the entire outer circumferential surface of the magnetic material portion constituting the magnetic head is removed.

The third embodiment is a magnetic head in which the track width regulating groove and the reprocessed damaged layer on the outer peripheral surface of the head are removed. The method shown in the first and second embodiments is used to remove the process-affected layer.

A coil was wound around each of the magnetic heads obtained in the first to third embodiments, and the reproduction output was examined. The results are shown in FIG.

For comparison, the reproduction output of a conventional magnetic head without the process-affected layer removed is also shown.

As can be seen from FIG. 3, the magnetic heads of each example exhibit better characteristics than the conventional example in the high frequency region. In particular, the third embodiment, in which the track width regulating groove and the processed damaged layer on the outer peripheral surface were removed, has a reproduction output of approximately 5% higher than that of the conventional example.
It has improved by dB. In addition, even in the second embodiment in which only the process-affected layer on the outer peripheral surface is removed, a reproduction output equivalent to that of an expensive laminated metal head used in business VTRs and the like can be obtained. (The ferrite head of the example can be manufactured at a lower cost than a laminated metal head.) In this way, the magnetic head from which the damaged layer has been removed can reliably improve the reproduction output in the high frequency region. Therefore, even if a high Bs ferrite material, which has been difficult to use in the past due to the degree of property deterioration due to the process-affected layer, is used for the core half block, if the process-affected layer is removed using the above method, it can be used as a high-Bs material. A magnetic head that fully utilizes its features can be obtained.

In addition, in the above embodiment, the bulkhead in which the gap abutment surface itself is made of the same magnetic material (ferrite) has been described, or even in the MIG (metal-in-gap) type helad as shown in FIG. A similar effect can be obtained by removing the process-affected layer. In Figure 4, 20
．． 20a is a core half made of ferrite, 21 is a magnetic alloy film having a higher saturation magnetic flux density than ferrite, 22 is a track width regulating groove, and 23 is glass molded into the track width regulating groove 22. At least one of the process-affected layers formed on the track width regulating groove 22 (outer surface of the magnetic alloy film 21) and the outer peripheral surface of the magnetic part of the magnetic head is removed by the same method as in the above embodiment. do.

(Effects of the Invention) As described above, the magnetic head according to the present invention has significantly improved recording and reproducing characteristics in a high frequency region.

[Brief explanation of the drawing]

FIG. 1 is an external view of a first embodiment of the magnetic head of the present invention, FIG. 2 is a diagram for explaining the manufacturing process of the magnetic head, and FIG. 3 is a diagram showing the reproduction output of each embodiment. Figure 4 is M
An external view of an IG type magnetic head, FIG. 5 is a diagram showing the manufacturing process of a conventional magnetic head, and FIG. 6 is a diagram for explaining problems with the conventional magnetic head. 2, 2a... Core half block, 4a... Winding groove,
4b...Winding guide groove, 10...Sliding surface with magnetic tape, 11...Glass, 18.18a...Track width regulating groove, 19.19a...Abutment surface.

Claims (1)

[Scope of Claims] A magnetic head formed by abutting two core halves made of ferrite, comprising a track width regulating groove in which a non-magnetic material is molded and a process-affected layer on at least one of the outer peripheral surface of the magnetic head. A magnetic head characterized by removing.