JPS59107415A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a head having a long life by forming an SiO2 film and a silicate glass film on each of the gap forming surfaces of a pair of core chips to form a spacer and by bonding the core chips together with a glass chip having a softening point almost equal to that of the glass film so as to carry out firm bonding. CONSTITUTION:A pair of core chips 2 are worked to a prescribed shape, and the gap forming surfaces 2A are polished to specular surfaces. An SiO2 film 7 having a prescribed thickness is formed on each of the surfaces 2A by sputtering, and an SiO2-base glass film 8 consisting of SiO2, K2O, B2O3, CaO and PbO is formed on the film 7 by sputtering to form a gap spacer having a prescribed thickness. The film 8 is made thinner than the film 7. The core chips 2 are placed so as to bring the films 8 into contact with each other, and a prescribed pressure P is applied. Using a glass chip 9 having a softening point almost equal to that of the films 8, melt bonding is carried out under heating at a slightly higher temp. than the softening point of the films 8 in a state in which the glass of the films 8 shows about 10<7>-10<6>cps viscosity. The chips 2 are bonded together while maintaining the dimensional accuracy of the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head used in tape recorders, video tape recorders, etc., and more specifically, the present invention relates to a magnetic head used in tape recorders, video tape recorders, etc. Sin2) film and glass (SiOg/KzO/B2) whose main component is silicic acid provided on it
O3・CcLO@P7! IO) film formed by 1
A pair of core pieces are pressed together under a predetermined pressure, and a piece of glass having a softening point that is almost the same as that of glass whose main component is silicic acid is placed on the gap spacer part. The present invention relates to a magnetic head having a core whose gap length accuracy is improved by pressurizing and heating the core until it becomes a semi-molten state.

Among magnetic heads, those used as audio control heads of video tape recorders are shown in Fig. 1 (
(In order to make it easier to understand, only the thickness of the gap spacer is shown enlarged compared to other parts. The same applies to the following drawings.)

That is, in the figure, the core 1 is made up of a pair of core pieces 2.2 bonded to each other with a gap spacer 3 interposed therebetween. As is well known, the distance between the gap-forming surfaces 2 of both core pieces 2 (gap length) has an extremely important effect on the performance of the magnetic head, so it is important to have high dimensional accuracy and to avoid variations. required to be completed.

Conventionally, this part has been processed by the method shown in FIG. 2 (front view). In other words, in the same figure, 1
One or both of the two gap-constituting surfaces of the paired core pieces 2 (
FIG. 2 shows a case in which they are formed on both sides. ), the SiO2 film 4 is formed to be equal to the gap length, except for a portion. This SiO2 film 4 is formed by a so-called sputtering method that utilizes the phenomenon of scattering and vapor deposition of electrode material in addition to vacuum discharge. In this way S
A pair of core pieces 2 on which the i02 film 4 is formed are brought into contact with each other,
A piece of glass 6 is placed on the edge of the gap 5 where the SiO2 film is not formed, and heated to a temperature of approximately 1000'''C to melt the glass piece 6 and fill the gap 5. Both core pieces 2 Glue.

According to the conventional processing method described above, when sputtering is introduced, it is possible to form S L 02 with an extremely thin film thickness (for example, about 1 μm) to extremely accurate dimensions, and Since glass is filled in the void 5 and the core pieces 2 are bonded together, it is also possible to obtain a core' with strong adhesive strength. However, the glass piece 6 is 100
Since it is heated and melted to about 0°C, it diffuses into the space between the contact surfaces of both core pieces, and even if the dimensions of the 5i02 film are formed with great accuracy, the gap length of the product core cannot necessarily be finished with high precision. Also, there was a drawback that there was a lot of variation.

The present invention improves the above-mentioned drawbacks of the conventional manufacturing method of magnetic head cores, thereby providing a magnetic head with a gap length that is processed with high accuracy and a core with little variation. The aim is to provide heads at low prices.

In the present invention, a 5iCh film and a glass film mainly composed of silicic acid are provided on the gap forming surfaces of a pair of core pieces to form a gap spacer, and the surfaces are brought into contact and a predetermined pressure (1 to 3 kg) is applied.
It is desirable to apply a force of ) while heating,
At that time, a piece of glass having almost the same softening point as the glass whose main component is silicic acid is placed on the edge of the contact surface, and both the glass whose main component is silicic acid and this glass piece are brought into a semi-molten state. , the above object is achieved by mutually adhesively fixing them.

Embodiments of the present invention will be described below based on the drawings. FIGS. 3(a) to 3(e) illustrate a method of manufacturing a core using a magnetic head trap according to the present invention.

The method for manufacturing this core is carried out in the following process steps.

(α) A pair of core pieces 2 are processed into a predetermined shape, and the two surfaces constituting the gigang are given a mirror finish.

(b) A 5iOz film of a predetermined thickness is deposited on the two gap forming surfaces by sputtering (Fig. 3 0).
reference). This vapor deposition is preferably performed by the following method.

That is, the core is heated in vacuum at 200'C for 1°, and the core surface is heated to 02. CO2 and moisture are removed, (M-0,
2 with argon gas containing 1-1, OX 10-3~4
．． This is carried out under a pressure of approximately OX 10-3<Torr).

(C) Gala-X (SiOz"KzOllBxOaIICaO・
The standard composition ratio of the components indicated by PbO is '
SiO'z70-75chi (wt%, same below), Kz
013-17%, BzOa4-6%, Cα03-5%
, P, 1502-4) A film 8 is formed by vapor deposition by sputtering. This vapor deposition is preferably performed by the following method. That is, the exhaust was evacuated to 10-' (Torr) and argon gas containing 0.1 to 1% O2 was used for 2. O
X 10-3~4. The test is carried out under a pressure of about OX 10-3 CTorr).

The thickness of the film 8 is set to be smaller than the thickness of the film 7. When attempting to obtain a core having a gap length of approximately 1 .mu., it is desirable that the thickness of the film 7 be 0.30 to 0.35 .mu. and the thickness of the film 8 be approximately 0.15 to 0.20 .mu.. The membranes 7 and 8 form gap spacers.

(d) 1 of the core pieces 2 manufactured by step (C)
The surfaces of the glass membranes 8 whose main component is silicic acid are brought into contact with each other, and both are pressed with a predetermined force P (for example, a force of about 1-, 3 kg). Furthermore, a piece of glass 9 whose silicic acid has almost the same softening point as the main mature lath is placed on the edge of the abutting part (see figure (b)). Further, in this state, the entire glass is heated to a temperature at which the main component glass becomes semi-molten, that is, a temperature slightly below the glass softening point (<72° C. to 780° C.). As mentioned above, the temperature at which the glass piece 9 exhibits a viscosity of 107 to 106 poise is 1
Temperature If showing viscosity of 0 to 10 poise (750'C to 8
00°C), so by this heating,
Both the glass film 8 whose main component is silicic acid and the glass piece 9 are in a semi-molten state, and since both core pieces 2 are pressed, they are firmly adhered to each other.

FIG. 3e shows the completed core 1.

As shown in the figure, the glass piece 9 is in a semi-molten and solidified state.

According to the manufacturing method described above, since the glass film 8 mainly composed of 5iOa7 and silicic acid is formed by the sputtering method, each film thickness dimension can be formed very accurately. Further, since the glass mainly composed of silicic acid is in a semi-molten state and not in a liquid state, the thickness of the glass film 8 mainly composed of silicic acid is not reduced by pressure bonding. Since the softening point of 5iOz is about 1500°C, there is no decrease in thickness even if it is pressure bonded at this temperature. Furthermore, the ratio of the thickness of the glass film 8 whose main component is silicic acid to the total gap length is 30-40% in the above example, but at a temperature where the viscosity of the glass is about 0 to 10' poise. Due to the explosive bonding, even if the glass is bonded under heat and pressure, the dimensional accuracy of the entire gap length will not be affected because there is almost no fracture caused by the flow of the glass, and the dimensional accuracy of the gap length of the finished product core will be Very good condition.

Although the above embodiments mainly describe a magnetic head used as an audio control head for a video tape recorder, it is clear that the present invention can be effectively implemented with other magnetic heads.

The present invention makes it possible to easily manufacture a core in which the adhesion of a pair of core pieces is reliable, the gap length dimension f# is extremely high, and there is little wobble, thus improving the performance of the magnetic head. It has extremely excellent effects, such as improved performance and reduced cost.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a core used in the audio control head of a video chip recorder, Fig. 2 is a front view showing a conventional core processing method, and Figs. 3 (a) to (1) are in accordance with the present invention. FIG. 2 is a perspective view showing a method of manufacturing a core used in the magnetic head. 1...Core, 2.φ...Core piece, 2A...Fist/gap forming surface, 3...-gap spacer, 4.e...
SiO2 film, 5... void, 6... glass piece, 7
...5iOz film, 81111@・Glass film mainly composed of silicic acid, 9...Glass cantilever license applicant Tokyo Denki Kagaku Kogyo Co., Ltd. Representative Patent attorney Tsukamoto University Department Third Department Figure 1 Figure 3 Figure 2 b

Claims (1)

[Scope of Claims] A magnetic head having a core manufactured by bonding a pair of core pieces with a gap spacer interposed therebetween and following the steps (α) to (d) below. (α) Form a pair of core pieces into a predetermined shape, and finish the gap-forming surfaces by mirror polishing. (b) Form a silicon oxide (C3iOx) film with a constant thickness by sputtering on the gap-forming surfaces. (C) 5i02 above
The S L 02 film is further coated with a predetermined thin layer of silicic acid mainly composed of SaO2 by sputtering.
・2011B203-cao@Pbo) film is installed to form a gap spacer. (d) The surfaces of the glass films mainly composed of silicate of a pair of core pieces are brought into contact with each other, and the edges of the corresponding contact parts are brought into contact with each other. A piece of glass having a softening point almost the same as that of the glass whose main component is silicic acid is placed on the glass, and while pressing both core pieces together under a predetermined pressure, the glass whose main component is silicic acid has a viscosity of 10. Heat to a temperature that exhibits a viscosity close to the lower limit of the working temperature of '-106 poise and maintain the peak temperature for a predetermined time to bond both core pieces 1