JPH01201809A - Manufacture of magnetic head chip - Google Patents

Abstract

PURPOSE:To prevent the warping of a core block from being generated by welding plural kinds of glass pieces with different softening points after placing on the core block alternately and heating, and filling glass in the track groove of the core block. CONSTITUTION:The track groove 4 is formed extending over from the joint prearranging plane 2 of the core block 1 consisting of a ferromagnetic material such as ferrite, etc., with another core block to a head plane 3 at a prescribed interval, and a V-groove 5 is formed on the joint prearranging plane 2 of the core block 1 in a longitudinal direction. On the joint prearranging plane 2, the track grooves 4..., a short columnar glass piece 10 and the glass piece 20 are placed alternately. The glass pieces 10 and 20 are provided with different softening points, however, the same or approximate coefficient of thermal expansion is attached on them. The core block 1 prepared in such way is put in an electrical furnace (not shown in figure), and the glass pieces 10 and 20 are welded by heating, and welded glass pieces 10a and 20a are poured into the track grooves 4... and the V-groove 5, then, they are cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a magnetic herad chip used in a VTR or the like.

[Conventional technology]

This type of magnetic head chip is generally manufactured by the following method. First, glass is filled into the track grooves of the core blocks made of a ferromagnetic material such as ferrite, and after polishing off the raised excess glass, the surfaces to be joined (gap forming surfaces) of both core blocks are Further mirror polish.

Next, a gap spacer film of a non-magnetic material is formed on the surface of one or both of the core blocks to be joined, and with the surfaces of both core blocks butted against each other, the glass is fused by heating to bond both core blocks. Join the core blocks.

Then, a magnetic herad chip is manufactured by curve-polishing the top surface of the head having a gap in this core block assembly and slicing it at a predetermined azimuth angle at each track groove.

[Problem to be solved by the invention]

However, in the process of manufacturing a magnetic helad chip using the above method, in the step of filling the core block with glass, as shown in FIG. Since the heaping up is excessive, the difference in thermal expansion coefficient between the core block 100 and the glass 103 causes the core block 10 to
Distortion is added to 0, and warpage occurs. Therefore, even if the excess glass 103 is roughly polished, the core block 100 is adhesively fixed to the drawing board of the polishing device, and the surface 104 of the core block 100 to be joined is polished to a smooth mirror surface as shown by the dashed line A. When the core block 100 is peeled off from the drawing board, the warp of the core block 100 returns as shown in FIG. Therefore, when the joint surfaces of both core blocks are brought into contact with each other after the gap spacer film is formed, and the joint surfaces 4 are curved, it is impossible to form a magnetic gap with uniform spacing. was there.

[Means to solve the problem]

The present invention was made to solve the above problems,
The method is characterized by including a step of alternately placing a plurality of types of glass pieces having different softening points on a core block, heating the glass pieces to melt them, and filling the trunk groove of the core block with glass.

[Action of the invention]

When a plurality of types of glass pieces with different softening points placed on the core block are melted by heating, and the trunk groove is filled with glass and cooled, the glass pieces with a higher softening point are solidified first. Therefore, the thermal strain caused by the difference in thermal expansion coefficient between the core block and the glass piece becomes dispersed over time depending on the type of softening point, and as a result, an effect similar to annealing is obtained and the core block is less likely to cause distortion such as warping.

〔Example〕, Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a method for manufacturing a magnetic head chip according to an embodiment of the present invention. In FIG. 1, track grooves 4 are formed at predetermined intervals from a surface 2 (gap forming surface) to be joined with another core block to a head surface 3, and track grooves 4 are formed at predetermined intervals in the surface 2 to be joined to another core block 1 in the longitudinal direction. A V groove 5 is formed.

On the surface 2 to be joined of the core block 1, short columnar glass pieces 10 and glass pieces 20, which are filled in the track grooves 4 and the square grooves 5, are placed alternately.

Although the softening points of the glass piece 10 and the glass piece 20 are different, those having the same or similar thermal expansion coefficients are used. The core block 1 prepared in this way is placed in an electric furnace (not shown), etc., and heated to melt the glass pieces 1O and the glass pieces 20, and the molten glass 1
0a, 20a are poured into the track grooves 4... and ■grooves 5 and then cooled.0For example, if the softening point of the glass piece lO is higher than the softening point of the glass piece 20, first, Glass 10a is cooled and solidified. In other words, at this time, the thermal strain caused by the difference in thermal expansion coefficient between the core block 1 and the glasses 10a and 20a becomes dispersed over time, and an effect similar to that of annealing is obtained, and the core block 1 has no warpage. As shown in FIG. 2, the glass 10a, 20a is filled and solidified in a raised state in all the track grooves 4... and the V-groove 5 without causing any distortion.

In the example, two types of glass pieces 10 and 20 with different softening points were used, but if three or more types of glass pieces with different softening points are used, the thermal strain caused by the difference in thermal expansion coefficient can be reduced by 3. Since the particles are dispersed over time over a period of more than one stage, distortion occurring in the core block 1 can be reliably prevented. In addition, the softening point of the glass pieces to be used must also take filling workability into account, and is preferably about 500 to 600°C, and the temperature difference between the softening points of glass pieces with a high softening point and glass pieces with a low softening point. is preferably about 100°C. This is because if the temperature difference in softening points is large, when joining the joint surface 1a of the core block l (before the glass 10a with a high softening point melts, the glass 20a with a low softening point melts). This is because the core block 1 may melt and flow out from the track grooves 4, resulting in poor bonding of the core block 1.Furthermore, since the ends of the core block dissipate more heat than the center, the core block 1 If the length of the glass piece placed on the edge of the glass piece is longer than the length of the glass piece placed on the center part, the distribution of thermal strain over time will be made uniform as a whole. This is preferable because distortion can be more effectively prevented.

Furthermore, as shown in FIG.
On top are long columnar glass pieces 11 and glass pieces 2 with different softening points.
Place 1 on the side alternately, and block multiple cores at a time...
There is also a method of glass molding the trunk grooves 4 and 2 grooves S. In this case, as in the above method, due to the difference in solidification temperature of the glass pieces 11°21 with different softening points,
Thermal strain is dispersed over time, making it difficult for the core block 1 to be distorted.

When the track grooves 4 and grooves 5 of the core block 1 are filled with glass using the above method, the raised excess glass 10
a, 20a is roughly polished, and the joint surface 2 of the core block 1 is
Polish it to a smooth mirror finish. In this case, since there is no distortion in the core block 1, the surface to be joined 2 has the same flatness as mirror polishing.

When the mirror polishing is completed, a gap spacer film with a thickness of about 0.5 μm is attached to the polished surface, and the glass 10a is heated with the surfaces to be joined of other core blocks abutted against each other.
, 20a are welded and joined. In this case, since the temperature difference between the softening points of the two is about 100°C, the glass 20a with a lower softening point will not melt and flow out when the glass 10a with a higher softening point melts (through the gap spacer film). A gap of uniform size is formed.

When the joining of the core block is completed, the top surface of the head having the above-mentioned gap is polished into a curved surface, and each trunk groove 2 is
By slicing at an azimuth angle, a magnetic head chip can be obtained. The magnetic head tubes thus obtained all have a constant gap size and do not exhibit large variations in gap size.

Incidentally, the plurality of types of glass pieces 10, 20 may be placed separately on the core block l, or may be placed after being integrated in advance.

〔Effect of the invention〕

As is clear from the above description, according to the method for manufacturing a magnetic helad chip of the present invention, the difference in thermal expansion coefficient that occurs between the core block and the glass piece due to the difference in solidification temperature of multiple types of glass pieces with different softening points. Thermal strain caused by this process will be dispersed over time, producing an effect similar to annealing and preventing warping of the core block. Therefore, there is no large variation in the gap size of the magnetic herad tip, and the reliability is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the state of a core block in a glass molding process in a method for manufacturing a magnetic head chip according to an embodiment of the present invention, and FIG. 2 is a side view showing a state in which glass is molded into the core block. , FIG. 3 is a perspective view showing the state of the core block during the glass molding process in a method for manufacturing a magnetic head chip according to another embodiment, and FIG. 4 is a side view of the core block for explaining the problems of the conventional manufacturing method. It is a diagram. 1... Core block 4... Trunk groove 10... Glass piece with high softening point 20... Glass piece with low softening point.

Claims (1)

[Claims] (1) The feature includes the step of alternately placing multiple types of glass pieces with different softening points on a core block, heating the glass pieces to melt them, and filling the track grooves of the core block with glass. A method for manufacturing a magnetic head chip.