JPS5931772B2 - Manufacturing method of magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic head that has excellent wear resistance and suppresses color flicker despite its narrow track width.

Such magnetic heads are expected to be used in devices that record video signals and the like at high density on a medium such as a magnetic tape, and/or reproduce the signals from the medium, such as video tape recorders (hereinafter referred to as VTRs). , hereafter V
The explanation will be given considering the application to TR. As part of the trend toward high-density recording on VTRs, there is a trend toward narrowing the effective track width of magnetic heads. Recently, effective track widths of 60μ have appeared.

However, if the track width is narrow, the magnetic head rotates at high speed and wear resistance deteriorates, so conventionally, as shown in Figure 8, one or both of the metal parts are squeezed to make the effective track width smaller than that of the metal. A narrower magnetic head is generally considered, but the effective track widths in b and d in Fig. 8 are biased to one side, which causes the uneven contact phenomenon, and the performance and envelope are not good, and in c, both are reduced. However, since the glass is not filled therein, magnetic powder that has fallen off from the magnetic tape falls there, causing a so-called clogging phenomenon. Therefore, the shape a is currently the mainstream. Therefore, in order to satisfy both high density and abrasion resistance, a magnetic head with a metal material of 200 μm and an effective track width of 60 μm was adopted in the standard-1 VTR, following the shape of a above. Color flicker (crosstalk) was observed when recording and playing back color video signals. However, it has been found that this color flicker decreases as the metal is made smaller, as shown in FIG. 10, and becomes almost unnoticeable on the screen when the metal becomes smaller than 120 .mu.m. However, if the metal has a thickness of around 100 μm in such a shape, it cannot be put to practical use due to wear resistance. Therefore, it is conceivable to develop the magnetic head having the shape shown in Fig. 8(d) to create a magnetic head with a configuration in which both sides of a magnetic core having a desired head gap are reinforced with glass, as shown in Fig. 9. However, this method has drawbacks such as difficulty in achieving accuracy when the track width becomes as small as 60 μm, and difficulty in forming the necessary gap length by aligning the cores with each other. The above-mentioned color flicker is related to the size of the guard band on the magnetic tape, and the actual total thickness W is equal to 4/3 times the guard band G plus the effective track width T, that is, W.
It is known from experience that color flicker does not occur if 1=2G+T...1 is selected.

In view of the above points, the present invention provides a method for manufacturing a magnetic head that is suitable for wear resistance and high density, and one embodiment thereof will be described below with reference to the drawings.

Four first grooves 1a, Ib are formed on the ferrite wafer 11.
, lc, and Id are ground so that the width of each adjacent groove becomes a predetermined interval (a value that satisfies Equation 1 above) that is larger than the effective track width (FIG. 1).

Each of these grooves is filled with glass 2 whose softening point is higher than that of the glass for gap welding described later, and one surface of the wafer filled with this glass is mirror-polished (FIG. 2). A set of mirror-polished wafers (referred to as polished wafers 1 and 1) is prepared. At each shoulder of adjacent first grooves on one polished wafer IA, a first groove is formed along the first groove leaving a gap corresponding to the effective track width T on the wafer. Two grooves Ie, If, Ig, Ih, Ii, Ij are formed, and four thin films 3a, 3b, 3c, 3d are formed by vapor deposition or sputtering in a direction perpendicular to the two grooves. Figure 3). The thickness of this thin film is specified to be 1/2 of the required gap length, and the film is designed not to adhere to the surface where a gap will be formed in the future. On the other polished wafer IB, in a direction perpendicular to the first groove,
Winding grooves Ik, ll and glass insertion grooves Im, In, IO are formed, and further, on the surfaces of the four strips excluding the surface on which a gap will be formed in the future in the same direction, the thickness is 1 of the required gap length. Thin films 3e, 3f, 3g, and 3h having a thickness of 1/2 are formed by vapor deposition, sputtering, etc. (FIG. 4). A pair of wafers 1 treated in this manner are brought into contact with each other by inserting a glass rod 4 whose softening point is lower than that of the filling glass 2 into the glass insertion groove.

Thereafter, the glass rod is melted at a temperature lower than the softening point of the filled glass (FIG. 5). This molten glass permeates between the first groove and the opposing surfaces of each wafer on which the thin film is not formed, thereby integrating both of the wafers. Next, change this block to A - A', B -
B', C-C'. The surface of the cut block on the operating gap side is polished so that the gap depth d becomes the desired depth, as shown in FIG. Further, along the center of each first groove, that is, along the lines D-D' and E-E in FIG.
', F-F'. , and GG' to create a magnetic headnap as shown in FIG. In this magnetic hedock chip, the total thickness W2 acts on wear resistance, and the thickness W1 acts on densification that is involved in color flickering, so it improves wear resistance and
It is possible to suppress color flicker. The effective track width is determined by filling the first groove with glass and then grooving the second groove, which is much shallower than the first groove. This method can be said to be much easier to produce than the magnetic head having the shape shown in FIG.

[Brief explanation of the drawing]

Figure 1 shows a ferrite wafer with a first groove.
Figure A is a plan view, and Figure A is a front view. FIG. 2 shows the first groove filled with glass, in which A is a plan view and the opening in the figure is a front view. Figures 3 and 4
Each figure shows a set of polished wafers before abutting. Each figure A is a plan view, each figure opening is a front view, and each figure C is a side view. FIG. 5 is a perspective view of a block in which a set of wafers are butted, and FIG. 6 is a perspective view of a block in which this block is cut. The figure shows a magnetic head chip; Figure A is a plan view thereof, Figure 8 is a perspective view thereof, and Figures 8A, b, c, d and 9 are front views of conventional magnetic head chips, respectively.
FIG. 10 is a characteristic diagram of the total thickness of the magnetic core versus the crosstalk level. Explanation of main drawing numbers, 1A, IB...
・Fueritowe...1, 1a~Id...1st
Groove, 2...Glass with high softening point, Ie~Ij
......Second groove, 1k, 11...-Winding groove, Im, In, IO...Glass insertion groove, 3a~
3h...-Thin film, 4...Glass rod with low softening point.

Claims (1)

[Claims] 1 A plurality of first grooves are formed on a ferrite wafer at predetermined intervals larger than the effective track width, glass with a high softening point is melted and filled into the first grooves, and the wafer surface filled with this glass is is mirror-polished, and on each shoulder of the adjacent first groove on one polished wafer, the first groove is
A second groove is formed along the groove and on this wafer with a gap corresponding to the effective track width, and a wire is wound on another polished wafer in a direction perpendicular to the first groove. A groove and a glass insertion groove are respectively formed, a thin film for regulating the gap length is formed on one or both surfaces of a pair of wafers, and then the pair of wafers are abutted and inserted into the insertion groove. A method for manufacturing a magnetic head, comprising the step of melting glass having a low softening point to integrate the two wafers.