JPS6089807A - Magnetic head - Google Patents

Abstract

PURPOSE:To form a sufficiently large thin film boundary face without increasing the thickness of thin film by providing a notch reaching a core major part from a thin film edge made of a magnetic material so as to form the thin film as nearly isosceles trapezoid by the notch. CONSTITUTION:The magnetic head consists of the magnetic core major parts 1, 2 made of an oxide magnetic material (ferrite), thin films 3, 4 made of an alloy magnetic material such as ''Sendust'' added to a front gap F and a spacer 5. Then the thin film 3 is formed nearly as an isosceles trapezoid with the notches 8a, 8b having ridge lines 7a, 7c from the edges 3a, 8b of the thin film to side faces 1b, 1c of the core major parts 1, 2 and the opposed thin film 4 is formed similarly. Thus, a cross angle between imaginary lines orthogonal to the ridge lines 7a-7d and a gap F is large enough and the sufficiently large thin film boundary face is formed without increasing the film thickness as a conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetic head ≦2 suitable for recording and reproducing high frequency signals such as video signals on high coercive force media such as metal tapes.

(b) Prior Art In general VTRs (.beta. and VH8), oxide magnetic materials (ferrite) are often used as the core material of the magnetic conductor.

This is because it has excellent wear resistance and is easy to manufacture. For high coercive force media such as metal tapes, which are used for dense recording, the saturation magnetic flux density of this magnetic heave is not large (approximately 5,500 gauss), so it is possible to record by taking advantage of the performance of the medium. difficult to do. Therefore, a magnetic drum has been proposed in which a thin film of a metallic magnetic material (Sendust, etc.) exhibiting high saturation magnetic flux density is placed around the front gear dub, where magnetic saturation is most likely to occur.
-103116 @I). In order to avoid magnetic saturation at the interface between the oxide magnetic material and the metal magnetic material, this known magnetic lead is proposed to have a larger area than the front gear dub component surface. However, this is achieved by forming a thin film made of a metal magnetic material on the 81st side of the opposite side from the tape abutting surface. In order to make the surface sufficiently large, the thickness of the thin film must be increased, and it takes time to form the film.

9. Purpose of the Invention The present invention aims to provide a magnetic field that allows the above-mentioned boundary surface to be configured to be sufficiently strong for two people without increasing the thickness of the thin film while reducing the track width. be.

Furthermore, the present invention is intended to provide a high-yield magnetic field that can prevent peeling of the thin film and reduce the width of the tread to a predetermined size C.

B) Structure of the Invention The present invention is configured such that a thin film made of an alloy magnetic material exhibiting a high saturation magnetic flux density is attached to the front gap side surface of the main part of the magnetic core made of a high resistivity material, and only 3 faces the thin film. This relates to a magnetic head with a tape contact surface, in order to define the trail width of the front gap to be smaller than the full width of the tape contact surface when viewed from the tape contact surface side, from each edge of the thin film facing the front gear dub to the tape contact surface. A cutout is provided on the main ridgeline of the main part of the magnetic core that defines the contact surface, and the cutout shapes the shape of the thin film on the tape contact surface into a substantially isosceles trapezoid. That is.

Another aspect of the present invention is that the angle between the legs of the isosceles trapezoid and the imaginary line perpendicular to the front gap is 20° or more and 50° or less, thereby improving the manufacturing yield and making it less susceptible to gross talk. It is characterized by

(E) Embodiment FIG. 1 is a perspective view showing one embodiment of the magnetic head of the present invention. In the figure, for convenience of explanation, the total thickness (Wl) is shown larger than the length and width ratio of the magnetic head.

Also, the length of the front gear dub (F) (the opening is also greatly exaggerated).Furthermore, the coil f to be installed
Even if two are attached, illustration is omitted. Since the overall shape of this magnetic head is extremely small, for example, about 3 u in both length and width, when mounting two VTR rotors directly, the side surface (Sl) should be placed so that the tape contact surface (Sl) is on the outside. Consideration has been given to ease of handling by attaching a base (not shown) directly to the bottom so that it protrudes from the top.

This magnetic head consists of a magnetic core main part 11+ (21) made of an oxide magnetic material (ferrite) exhibiting high specific resistance, and a front gear dub (F) side surface (1) of the magnetic core main part.
a) (2a) A thin film (31i41) with a thickness of about 5 μm exhibiting a high saturation magnetic flux density made of an alloy magnetic material (for example, sendust) attached on top of the thin film (31i41), and a g2 attached 5
The base plate f(5) is made of a non-magnetic material such as i02. In addition, this magnetic head has a coil window (6) that passes through it in the thickness direction, and the upper edge of this coil window is configured so that it coincides with the lower edge (depth end) of the front gear dub CF). has been done.

Viewing the tape contact surface (Sl) from the front, each edge (6a) (3b) (of the thin film facing the front gap IF)
4a) From (4b), the main part of the magnetic core that constitutes the tape contact surface +11 (side surface (1b) (1c) (2b) on 21
(2cN ridge line (7a) (7b) (7c) (7d)
(8a), (8b), (8c), and (8a), with all the cutouts (8a), (8c), and (8b), (8d) 1: Glass (9a) (9b) acting as a bonding material. It is filled. Therefore, the thin films (3) and (4) are both shaped to have a substantially isosceles trapezoid shape. Upper base (3c) (4
c) is equal to the travuk width (T), -do base (3d) (4
d) is larger than the Travuk width (Tl) and smaller than the total thickness (Wl).

The front gear dub (the extending direction of Fl is deviated from a right angle by 10' with respect to the normal traveling direction CP of the magnetic heave), and is configured to have a small Wayurus angle (α).

Then, each leg side of the isosceles trapezoid, that is, the ridge line (7a) (
Intersection angle (θ+) (θ2) (θ5) between 7b) (7c) (7d) and the virtual line αe perpendicular to the front gear dub (F)
(θ4) is defined to be greater than or equal to 20' and less than or equal to so (see FIG. 9).

FIGS. 2 to 4 briefly show examples of manufacturing a magnetic head according to the present invention. Wafer (2) made of magnetic ferrite material
On one side of 1J [Thin film of sendust (2
11 is attached to the entire surface, and furthermore, a spacer film 8i02 (not shown) is attached to the front gap planned surface on this thin film by half of the required gap length. Next, a land portion (21a) having a width matching the tiger stitch width (T) is formed.
A plurality of (six in the illustrated example) grooves ciz are opened so as to form the following grooves. Figure 2 shows the professionally processed eight-piece
A perspective view of the front (B1) is shown. The other professional call 8-f (Blt) that is opposite to this professional dripping haakani in Figure 2
teeth.

In addition, there is a groove (
2) is as shown in Fig. 3, where the above-mentioned drip width regulation m (22 is opened in two orthogonal directions.) (B1) (Bi is shown in Fig. 4). As shown, the thin films tant2n are butted against each other, and the inside of the groove for defining the width of the tab is filled with glass to integrate them.The surface (Ha) of the integrated pro-fit tBl is R
Process the attachment and pound the tape contact surface (B2), then slice this professional plate along the broken line (to) so that it has an azimuth angle of 1♂, process the thickness as necessary, and make it 1♂.
A magnetic heave shown in No. 17 is manufactured.

Here, a supplementary explanation will be given of the method of machining the track width defining groove ez. Figure 5 is a plan view showing the state in which the workpiece, the product (B1), is being cut at the cutter cape (however, the power cutter is shown as an imaginary line to make it easier to see in Figure 1).
(FIG. 6 is a cross-sectional view taken along line 6-2 in FIG. 5.

Carter■ is a disk-shaped diamond casator with an angle (θ), rotates in the direction of the arrow (to), and moves toward the center line (
Lower 1 in the upper region of 301; acts to cut the advancing workpiece (B1) and move away from the workpiece in the lower region. According to experiments, groove c! The tendency of peeling between thin films during the cutting process of (b) Shows the case of o, 2/BeO and c-mouth 10° 1 mm7 sec. Both are angles (
It is shown that when θ) becomes smaller than 20, the probability of occurrence becomes extremely large. This phenomenon can be understood as follows.

If this angle (0) exists even slightly, under ideal conditions there would be no chance of contact between the forceps tool blade surface and the machined surface of the workpiece in the area below the center line 3, so the above peeling would not occur. However, in reality, in the range where the above angle If (θ) is small due to the deflection of the carter or the expansion of the blade that is elastically deformed during the force cutting operation, the carter (to) will become workpiece CB+ even in the area below the center line Kit. The above intersection angles (01) to (B
Since 4) corresponds to this angle (θ), it is selected to be 2♂ or more in order to prevent thin film peeling and improve manufacturing yield.

) On the other hand, increasing the angle (θ) above increases the track width (
1') becomes 1.

This will be explained with reference to No. 81. Work (B1
Even if the thickness IDI of ) is set to a predetermined value of 1iii[ and the reference position iQ1 is set to 7dat, Carter's workpiece (
When the access to B1) changes from the predetermined solid line state to the adjacent broken line state, the traffic drop width ITI changes to (
T1) to C''X'l), and the tendency of this change depends on the magnitude of the angle (θ).

If the angle (θ) is large, the track width (T) can be determined with a small error.
This will result in large fluctuations in By finishing the thickness variation of the workpiece (Bl) to within 1 μm and devising C to eliminate unevenness in the thickness of the adhesive layer when fixing the workpiece to the guard stand, trouble is achieved when the angle (θ) is up to about 50'. ±2 μm tolerable variation in fitting width (T)
It is relatively easy to keep it within l2. Therefore, the intersecting angle (
B1) to (B4) are suitably 50 degrees or less.

Increasing this intersection angle also has the disadvantage of increasing the noise component in the low frequency range. We will explain this point with reference to Figure 9. The figure shows the recording state of Toradaku B (two adjacent Tora A's).

At the time of recording, the original signal is recorded at the azimuth angle α (-R1) by the front gear dub (F) on the front gear, and the ridge line (7d) is also recorded on the B track adjacent to the recorded edge.
Since Jf-y acts as a gap, a leakage record parallel to the ridge is made. During playback of the B trike, this leaked recording component is transmitted to the front gear dub (
In order to avoid reproduction in F), the angle β in the figure needs to be 20 or more, which causes azimuth loss. β-90-〇-2
Since α (here α-10°), β-70-〇(Yu2
From 0).

Therefore, it is appropriate that the intersecting angles (θ1) to (θ4) be 50° or less in order to avoid reproducing leakage recorded components.

(E) Effects of the Invention The magnetic head of the present invention has the front gear droplet periphery made of a metal-containing magnetic material with a high saturation magnetic flux density (for example, sendust), so that the recording current for recording on a metal tape is Even if the size is increased, there is no risk of magnetic saturation, and since the main part of the magnetic core is made of a high resistivity oxide magnetic material (e.g. ferrite), the playback output characteristics can be improved easily against eddy current loss. It is easy to manufacture because it is not susceptible to deterioration and can use established manufacturing methods. Furthermore, the interface between the 1-alloy magnetic material and the oxide magnetic material can be made larger by increasing the above-mentioned intersection angle, and there is no need to increase the film thickness as in the conventional example, making manufacturing easier in this respect as well. It is. Furthermore, the above intersection angle is 2O2 or more and 50° or less L
= is selected, it is possible to prevent peeling of the thin film on the main part of the magnetic core and improve the accuracy of the track width. At the same time, be careful not to play back the leaked recorded components (because it will cause
/ N characteristics can be improved.

[Brief explanation of the drawing]

The drawings are all related to the present invention C2, and FIG. 1 is a perspective view of the construction of one embodiment, FIGS. 2, 3, and 4 are explanatory diagrams of the manufacturing process of this magnetic head, and FIG. The figure and No. 6 tooth are a plan view and a cross-sectional view for explaining the culling operation, No. 71 (A) extension) is a characteristic diagram of the probability of occurrence of thin film peeling, and Figs. 8 and 9 are both the upper limit of the intersection angle. It is an explanatory diagram. Explanation of main number 1 (1 bar 2)... Main part of magnetic core, (3) (41...
Thin film, (F)...Front gear pump, (7a) to (7
d)...ridge line. (θ1) ~ (θ4)... Intersecting angles Figure 1 Figure 2 - Figure 8 Figure 7 (A) (B) Figure ◎

Claims (1)

[Claims] fil A thin film made of a 1-alloy magnetic material is attached on both sides of the front gear dub as viewed from the tape contact surface side. In order to define the width of the front gear dub, the total width of the tape contact surface is calculated from each section of the # membrane facing the front gear dub. A magnetic device characterized in that the thin film has a notch having a ridgeline extending to the top surface of the main part of the magnetic core as defined by h+i, and the shape of the thin film on the tape contacting surface is formed into a substantially isosceles trapezoid. Vdo. (2) The angle of displacement between the leg sides of the isosceles trapezoid and the imaginary line perpendicular to the front gear dub is set to 2♂ or more and 5 []' or less. 1) Add to the magnetism of the paper.