CN1100224A - Method for fabricating a magnetic head - Google Patents

Abstract

A method of manufacturing a magnetic head includes the steps of stacking a magnetic material layer on a ceramic substrate, coating adhesive along the magnetic material layer when the substrate rotates at a predetermined speed, and forming a magnetic head by stacking several substrates. The substrate assembly and at least one pair of magnetic ferrite elements are obtained by slicing the substrate assembly in vertical and longitudinal directions. When the element is rotated at a predetermined speed, the adhesive is uniformly and stably applied to the gap-forming plane of the magnetic ferrite element, and a pair of ferrite elements are pressed to adhere to each other, thereby making a magnetic head .

Description

The present invention relates to a method of manufacturing a magnetic head, and more particularly to a method in which, in order to bond magnetic core elements at conventional temperatures, each magnetic core of a magnetic head fixed on the turntable of a rotary applicator The components are uniformly and stably coated with a liquid adhesive under the high-speed rotating state of the turntable at the normal temperature, so that the magnetic core components are bonded to each other. Thus, thickness variations are conveniently controlled without degrading head performance.

With the increase in the recording density of magnetic tapes used as recording media for video tape recording apparatuses, magnetic tapes having a high residual magnetic flux density Br and a high coercive force Hc, that is, metal magnetic tapes, have been widely used by using an adhesive material to Metal powder is coated on a non-magnetic substrate to form a magnetic recording layer. When the magnetic head is used for metal magnetic tape and digital audio tape, the magnetic field strength at the magnetic gap part of the magnetic head must be increased due to the high coercive force of such magnetic tape. In the erasing magnetic head used to erase the signal recorded on the magnetic tape , requiring a higher saturation flux density.

Therefore, a magnetic head has been developed by using a spray coating technique by laminating a ferromagnetic thin film having a high saturation magnetic flux density on a magnetic gap forming plane of a magnetic ferrite element made of metal oxide. obtained, which will be schematically introduced below.

Referring to Figure 1, there is shown a typical magnetic head manufactured using conventional techniques and having a pair of magnetic core elements 10 and 12 made of a ferromagnetic substance such as ferrite. The magnetic core element 10 has a coil slot 14 around which a coil 18 is wound, and a reinforcement slot 16 . Connecting grooves 20 for limiting the track width are formed on opposite sides of the pair of magnetic core elements 10 and 12 , and bonding glass 22 having a predetermined melting point is poured to fill the connecting grooves 20 and reinforcing grooves 16 . By means of the bonding glass 22, a pair of magnetic core elements 10 and 12 can be bonded to each other.

An overlapping layer 24 of silicon dioxide SiO ₂ is formed on a contact plane containing the track width limiting connection groove 20 of the magnetic core element 12 . As shown in Figure 2, the overlapping layer 24 is composed of multiple layers, such as the first non-magnetic metal thin film layer 24a containing chromium Cr, the ferromagnetic ferromagnetic aluminum silicon iron powder of Fe-Al-Si (Sendust) alloy. The thin film layer 24b, the first nonmagnetic thin film layer 24c containing SiO ₂ , the second nonmagnetic metal thin film layer 24d containing Cr and the second nonmagnetic thin film layer 24e containing SiO ₂ cover the surface of the magnetic core element 12 in sequence.

Here, the use of the first nonmagnetic metal thin film layer 24a is to improve the bonding strength between the ferrite core element 12 and the sendust layer 24b, and the first nonmagnetic thin film layer 24c of SiO ₂ and the second Two nonmagnetic metal thin film layers 24d are used to form a magnetic gap.

This head is suitable for use with digital audio tape recorders, digital video tape recorders, or 8mm video tape recorders. A pair of magnetic core elements 10 and 12 are composed of a ferromagnetic substance such as single crystal ferrite of the Mn-Zn family, and have a nonmagnetic thin film layer of _SiO2 in the magnetic gap. A method of manufacturing the conventional magnetic head shown in FIG. 1 will be described in detail with reference to FIGS. 3A to 3F.

3A to 3F show assembly manufacturing steps of the magnetic head shown in FIG. 1. FIG. As shown in FIG. 3A, a pair of magnetic core elements 10a and 12a are shaped into a predetermined rectangle by cutting a ferromagnetic substance such as ferrite. At least one contact plane intended to be bonded, for example, a plane of the magnetic core element 12a has been ground for smoothness, along the longitudinal direction of the magnetic core elements 10 and 12a, there are connection grooves 20 with predetermined intervals for limiting the track width . The magnetic core element 10a has a coil slot 14 and a reinforcement slot 16 in this order along its longitudinal direction.

As shown in FIG. 3B, on the magnetic core element 12a, the overlapping layer 24 shown in FIG. The first nonmagnetic thin film layer 24c, the second nonmagnetic metal thin film layer 24d and the second nonmagnetic thin film layer 24e are obtained. Furthermore, _SiO2 -PbO-based glass 22a is applied to the track width limiting connection groove 20, the coil groove 14, and the reinforcement groove 16 of the magnetic core element 10a.

As shown in FIG. 3C , the glass 22a is heated and melted first, and then the glass 22a with a low melting point is poured into the track width limiting connection groove 20 , the coil groove 14 and the reinforcing groove 16 . As shown in FIG. 3D, the lower portion of the coil groove 14 is exposed by grinding off the glass 22a having a low melting point poured into the coil groove 14. As shown in FIG. The glass 22a flowing out of the track width restricting connection groove 20, the coil groove 14, and the reinforcement groove 16 is removed by wiping or the like.

Then, glass 22a having a low melting point is sputtered to the bonding plane of the magnetic core element 10a. As shown in FIG. 3E, the magnetic core elements 10a and 12a facing each other to be bonded are secondarily heated to the melting temperature of the glass 22a so that the magnetic core elements 10a and 12a can be bonded to each other by the glass 22a.

As shown in FIG. 3E, the magnetic core elements 10a and 12a that are completely bonded are cut along the cutting line C, and at the same time, the unnecessary part is cut along the cutting line D at the bottom of the reinforcing groove 16, so that at least one is obtained as shown in FIG. 3F. The semi-finished magnetic head shown. The plane contacting the magnetic recording medium is ground into an arc shape, and the coil 18 is wound on the coil groove 14 to obtain a magnetic head having the structure shown in FIG. 1 .

However, when assembling and manufacturing a conventional magnetic head, especially when two magnetic core elements are bonded to each other, it is difficult to control the length of the gap by pouring or sputtering glass onto the magnetic core elements constituting the magnetic head. Adjust the thickness variation of the glass layer. In addition, due to the coating spreading characteristics of glass, it is possible to operate several magnetic core elements simultaneously, which hinders improvement in productivity. In addition, because the bonding process is generally carried out between 400°C and 700°C, the magnetic properties of the material tend to deteriorate.

In other words, the bonding glass must have hardness and expansion properties that allow the two core elements to be firmly bonded to each other without air bubbles. However, the bonding glass used for the conventionally manufactured magnetic head generates air bubbles due to the reaction with the overlapping layer. The air bubbles form holes inside the glass and appear on a plane in contact with the recording medium, thus scratching the recording medium.

The present invention intends to solve the above-mentioned problems. It is therefore an object of the present invention to propose a method of manufacturing a magnetic head in which, in order to bond magnetic core elements at conventional temperatures, each magnetic core element of a magnetic head fixed on the turntable of a rotary applicator At a normal temperature, a liquid adhesive is applied evenly and stably under the condition that the turntable is adjusted and rotated, so that the magnetic elements are bonded to each other, so that the thickness variation is conveniently controlled without degrading the performance of the magnetic head.

In order to realize the above-mentioned invention object, a kind of magnetic head manufacturing method is provided, and this magnetic head is used for recording audio frequency and/or video signal on the magnetic recording medium and replays the recorded signal, the steps that this method comprises are:

A layer of magnetic material is stacked on a substrate made of a material with high magnetic permeability, and heat-treated;

A heat-treated substrate on a chuck mounted on a turntable is rotated at a predetermined speed while an adhesive is lowered and coated at a constant rate from a height that does not cause sputtering at normal ambient temperature. On the substrate, the viscosity of the adhesive is suitable for the rotational speed, and the adhesive has uniform and stable coating characteristics by making the amount provided just suitable for the rotational speed;

stacking and bonding adhesive-coated substrates in sequence to form a substrate assembly;

Cutting the substrate assembly at right angles along a predetermined direction so as to obtain at least one pair of magnetic ferrite elements constituting a plurality of magnetic heads;

A coil slot and a reinforcement slot are formed in one of the pair of magnetic ferrite elements;

Applying the adhesive to a predetermined thickness on the gap forming plane by rotating the other magnetic ferrite element among the pair of magnetic ferrite elements at the same rotational speed and at the same temperature as above;

Bonding a pair of magnetic ferrite elements at conventional temperatures;

cutting the bonded magnetic ferrite elements along a predetermined direction to obtain a magnetic head having a pair of magnetic ferrite elements; and

The surface of the magnetic head that contacts the magnetic recording medium is ground to have a circular arc shape.

In this method of manufacturing a magnetic head, the adhesive is uniformly and stably applied to the magnetic ferrite element by being dropped from a nozzle above a spin coater with adjustable rotation and has a hardness suitable for bonding.

From the viewpoint of ensuring the thickness of the adhesive, the rotational speed of the spin coater should preferably be precisely controlled.

Therefore, it is a priority to arrange each magnetic ferrite element to be fixed on a rotary coating machine with a turntable, and when the rotary coating machine rotates at a high speed, the adhesive sprayed from the nozzle of the rotary coating machine can be uniformly and stably Coated along magnetic ferrite elements.

In addition, the viscosity of the adhesive is 60-100 g/cm.s, and the rotation speed of the spin coater is 6000-20000 rpm.

Preferably, the nozzle above the spin coater has a vertical height of 5 cm relative to the magnetic ferrite element, and the bonding step with the adhesive is carried out at a conventional temperature below 100°C.

Objects and other advantages of the present invention will become more apparent by describing in detail various preferred embodiments with reference to the accompanying drawings, wherein:

Fig. 1 is the perspective view of the magnetic head that utilizes conventional technology to make schematic representation;

Figure 2 is an enlarged plan view of the magnetic head shown in Figure 1;

3A to 3F show the manufacturing process of the magnetic head shown in FIG. 1;

4A to 4J show the manufacturing process of the magnetic head of the present invention;

Fig. 5 is the general view that utilizes the bonding process of the spin coater that the present invention adopts in order to facilitate understanding;

Fig. 6 is a side view showing a method of applying an adhesive using a spin coater;

Fig. 7 is a plan view of the coating method shown in Fig. 6 .

Referring to Fig. 4 representing the method for manufacturing the magnetic head of the present invention, the magnetic head is manufactured in such a manner that, for example, a magnetic material layer 102 of sendust powder of a Fe-Si-Al alloy is stacked on a ceramic substrate 100, as shown in FIG. The thickness shown in 4A is, for example, about 5-15 microns, followed by heat treatment (FIG. 4B). The ceramic substrate 100 on which the magnetic material layer 102 is stacked is rotated by a spin coater which will be described later.

In addition, the spin coater rotates at a predetermined rotational speed such as 6000-20000 rpm. At this time, as shown in FIG. 4C , the adhesive 104 falls onto the magnetic material layer 102 and covers the magnetic material layer 102 evenly and stably due to the rotating force of the spin coater. Preferably, the adhesive 104 is applied to a thickness of about 800-1000 Angstroms.

Several substrates 100 coated with an adhesive 104 are bonded to each other to form a substrate assembly 200 as shown in FIG. 4D.

Utilize a suitable microtome to cut the substrate assembly 200 shown in Fig. 4D, cut along the arrow A and B direction as shown in Fig. 4E, in order to manufacture several magnetic irons as shown in Fig. 4F Oxygen elements 300 and 400 .

In addition, as shown in FIG. 4G , the magnetic ferrite element 400 has a coil slot 401 , a reinforcement slot 402 and a track width limiting connection slot 403 . The magnetic ferrite element 300 is coated with an adhesive 301, which will be described in detail with reference to FIG. 5 below.

FIG. 5 is a schematic view for explaining the application of an adhesive 500 on the magnetic ferrite element 300 to bond the magnetic ferrite elements 300 and 400 shown in FIG. 4H to each other.

The magnetic ferrite 300 arrangement constructed as described above is fixed on the clamping device 600, which is then fixed on the turntable 700 of the spin coater by suitable means. When the turntable 700 rotates at a high speed, such as 6,000 to 20,000 rpm, at a conventional temperature such as lower than 100°C, the liquid adhesive 500 is dropped from the nozzle 501 above the spin coater, so that the liquid adhesive 500 is coated on the magnetic ferrite element 300 with a thickness of, for example, 500˜1000 angstroms. At this time, the preferred value of the spacing<vertical height) between the nozzle 501 and the magnetic ferrite element 300 is about 5 cm.

As shown in FIG. 6 and FIG. 7 , due to the centrifugal force of the rotating turntable 700 , the coated liquid adhesive 500 can be uniformly and stably coated along the gap of the magnetic ferrite element 300 to form a plane. Thus, any adhesive with excellent adhesive properties is likely to be good enough for the liquid adhesive 500, but an inexpensive, readily available epoxy-based adhesive is preferred. In addition, it is preferable that the liquid adhesive 500 has excellent coating properties, hardness, and viscosity without generating air bubbles. The adhesive used in the present invention has a viscosity of 60 to 100 poise (g/cm.s), preferably about 80 poise.

After the adhesive is applied, the rotation of the turntable 700 is stopped. The clip device 600 provided with the magnetic ferrite element 300 is then separated, and the magnetic ferrite elements 300 and 400 are brought into pressure contact with each other by applying a predetermined pressure, thereby achieving bonding (see FIGS. 4I and 5 ).

As shown in Fig. 4J, for the need of contacting with the magnetic recording medium, the glass 800 of wear-resistant material (SiO ₂ ) is coated on the upper part of the track width limiting connection groove by conventional methods.

After that, dicing is performed similarly to that shown in FIG. 3E, and the upper surface thereof is processed into a circular arc shape in order to assemble a magnetic head.

In the present invention described above, in such a state that the magnetic ferrite element 300 arranged to be fixed on the clamping device 600 rotates at a high speed, the liquid adhesive 500 descends and passes through the action of the centrifugal force of the turntable 700 to be evenly stabilized. Thus, when compared with the conventional method of bonding magnetic ferrite elements to each other by inserting glass rods, it appears that the thickness variation of the adhesive is very controllable.

In addition, in order to improve productivity, adhesive is applied after arranging multiple magnetic ferrite elements on the clamping device. Since the coating of the liquid adhesive is carried out at normal temperature, the magnetic characteristics of the magnetic head will never be deteriorated.

As described above, according to the magnetic head manufacturing method of the present invention, after the magnetic ferrite element of the magnetic head has been fixed on the turntable, when the turntable rotates at a high speed, in order to bond two magnetic ferrite elements at a conventional temperature, uniform The liquid adhesive is applied stably so that the performance of the magnetic head never degrades, and the thickness variation of the adhesive is easily controlled.

While the present invention has been shown and described with reference to particular embodiments, it will be understood that various changes in form and details may be made therein by persons skilled in the art without departing from the teachings and descriptions herein. The inventive concept and protection scope of the present invention defined by the claims are proposed.

Claims (5)

1, a kind of manufacture method of magnetic head, this magnetic head are used on magnetic record medium record audio/vision signal and the signal reproduction that is write down are reset, and its step that comprises is:

A stacked magnetic material layer on the substrate that constitutes by the high permeability material, and it is heat-treated;

Make and be positioned at rotating by predetermined speed on the clamp device that is installed on the rotating disk through heat treated substrate, simultaneously under conventional environment temperature, never can cause on the height of sputter according to constant ratio a kind of bonding agent is fallen and coated to this substrate, the viscosity that bonding agent has is suitable for this rotating speed, by making the quantity that provides just be suitable for this rotating speed, make bonding agent have uniform and stable coating characteristic:

Some substrates of the stacked in order and bonding bonding agent of coated are to form a substrate assembly;

Press the right angle to this substrate group cutting along a predetermined direction, so that obtain the magnetic ferrite body member that at least one pair of constitutes some magnetic heads;

A magnetic ferrites element internal in the pair of magnetic ferrite component has the coil groove and reinforces groove;

,, form in the slit on the plane the bonding agent coated by being rotated in another magnetic ferrite body member in the pair of magnetic ferrite component with under identical temperature according to rotating speed same as described above to a predetermined thickness;

Bonding pair of magnetic ferrite component under conventional temperature;

By bonding magnetic ferrite body member, obtaining having the magnetic head of pair of magnetic ferrite component, and the plane that contacts with magnetic recording medium of lapping magnetic heads makes it to be circular arc along predetermined direction cutting.

2, magnetic head manufacturing method as claimed in claim 1, the viscosity of wherein said bonding agent are 60～100 gram per centimeters. second.

3, magnetic head manufacturing method as claimed in claim 1, the described rotating speed of wherein said spin coated machine is 6000～20000 rev/mins.

4, magnetic head manufacturing method as claimed in claim 1, the nozzle above the machine of removing is applied in described rotation wherein and the vertical distance of described magnetic ferrite body member are 5 centimetres.

5, magnetic head method as claimed in claim 1 is made wherein bonding step and is and utilizes described bonding agent to carry out being lower than under 100 ℃ the conventional temperature.

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