JPH01263907A - Thin film type multiple element magnetic head - Google Patents

Abstract

PURPOSE:To eliminate the dispersion of performance and to obtain a desired magnetic tape contact pressure by equalizing the curvature radius of points, at which the magnetic gap of three magnetic heads is at '0', with the curvature radius of the points on the tape sliding surface of the respective magnetic heads, and specifying the curvature radius. CONSTITUTION:At least three magnetic head elements 3a-3c are formed on the same substrate, and in a thin film type multiple magnetic head 1 mounting the elements on a rotary cylinder 2, a curvature radius R of points 4a to 4c at the gap depth '0' of the mutually adjacent magnetic head elements 3a to 3c is made approximately the same as the curvature radius of the gap tips (tape sliding surface) of the magnetic head elements 3a to 3c. Further, the curvature radius R is in the range of 1/4 of a rotary cylinder radius RS. Thus, the gap depth of the respective magnetic head elements are made the same, the dispersion is not generated in a feature, a life can be extended, and the tape contact pressure for the respective magnetic heads can be made the same in the best conditions.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a nine-element thin film magnetic head in which at least three magnetic head elements are arranged on the same substrate, and particularly relates to a method for improving the gap depth of each magnetic head element. The present invention relates to a multi-element thin-film magnetic head that can make the performance of the magnetic head substantially equal.

[Conventional technology]

Conventionally, there is a method described in Japanese Unexamined Patent Application Publication No. 60-45915 in which a plurality of magnetic heads are formed on the same substrate using thin film technology. A magnetic gap for multiple tracks, for example, two tracks, is provided on the flat sliding contact surface.
No consideration is given to arranging at least five or more magnetic head elements along the direction of relative movement of the magnetic tape.

On the other hand, as shown in FIG. 6, a thin film magnetic head used in a rotating magnetic hept of a VTR has two magnetic head elements on the same substrate 1 (in the figure, only the magnetic thin film portions are indicated by 1, 5α, and 5b). ) are arranged closely along the direction of rotation of the head. The upper part of the substrate 1 is polished so as to obtain a predetermined gap depth h in the magnetic gaps 5α and 5h, and a tape sliding contact surface 6 with a predetermined curvature is formed.
is formed.

Thereafter, the substrate 1 is mounted on a rotating cylinder (not shown) so that the tape sliding surface 6 slightly protrudes from the outer periphery of the rotating cylinder, thereby completing a rotating head. In the thin film magnetic head shown in FIG. 6, the gap depth is cited as a factor that influences the performance of each magnetic head element 5α, 5A.
In order to make the characteristics uniform, it is necessary to ensure that there is no variation in the gap depth between people. Note that PI and P2 are points with zero gap depth, and 7 is a straight line connecting the points with zero gap depth.

In FIG. 6, since only two thin film magnetic head elements are formed on one substrate, the gap depth h-4 (in order to align the gear rip depth zero point P1, P2 (and the straight line 7
) are the same height, and the gap 5a in the sliding surface 6,
In a rotating magnetic head device in which five or more thin film magnetic heads are arranged closely on one substrate and this substrate is mounted on a rotating cylinder, each magnetic head element needs to be aligned at the same height. No consideration is given to problems such as variations in performance that occur between the two methods.

By the way, recently, the number of magnetic head elements mounted on one rotating cylinder has increased to 9 or 8 to 12 in 8mm movie camera integrated VTRs, digital VTRs, etc. Five or more magnetic heaving elements are now arranged close to each other in the rotational direction at one location on the top. In this case, a so-called double azimuth head is constructed by making the magnetic gap directions of the front and rear magnetic head elements different. For this reason, three or more magnetic head elements before and after each are manufactured separately and not on the same substrate.

[Problem to be solved by the invention]

In all of the above conventional techniques, at least three magnetic head elements such as double azimuth are formed on the same substrate in close proximity in the rotational direction using thin film technology, and this substrate is mounted on a rotating cylinder and rotated. No consideration was given to the problem of variations in gap depth between head elements of a multi-element thin film magnetic head, which occurs when obtaining a magnetic head.

After creating and cutting out these five or more magnetic heads separately using thin film technology, one by one to achieve a predetermined gap depth.
In the method of polishing two tape sliding surfaces and combining them,
The number of work steps increases.

On the other hand, in a rotating head, five or more magnetic head elements adjacent to each other in the front and back are arranged so that the contact pressure (head contact) with the magnetic tape is as much as possible on the tape sliding contact surface of the magnetic head elements. It is necessary to design the shape and position of the In the case of two adjacent magnetic head elements as shown in FIG. 6, the sliding surfaces 6 should be polished so that the gap surface on the sliding surfaces 6 protrudes from the outer periphery of the rotary cylinder by a predetermined length of the same length. good. However, the shape of the tape sliding contact surface is such that it applies a desired contact pressure to three or more adjacent magnetic head elements.
The location was not even considered.

Therefore, the case of two magnetic head elements in FIG. 6 is expanded to the case of five or more magnetic head elements, and five magnetic thin films 3
, 54. sc is the point Pl where the gap depth is zero
, P2. It is conceivable to form the tape so that Ps has the same height (on the straight line 7) and then polish the upper surface into an arc shape to form the required tape sliding contact surface (not shown). However, in this method, the magnetic gap depth of the central magnetic head element 3b becomes larger than the magnetic gap depth of the magnetic head elements 5a and SC before and after it, so the characteristics become inconsistent and the tape sliding contact deteriorates as the magnetic head element 3b is used. As the surfaces wear out, a problem arises in that the front and rear magnetic head elements 5α and 5c deteriorate faster than the central magnetic head element 5b.

Therefore, it is an object of the present invention to solve the problems of the prior art described above, and to provide at least three images on the same substrate in the front and back of the rotational direction of the head.
In a thin-film multi-element magnetic head for a rotating magnetic head in which several magnetic head elements are arranged close to each other, it is possible to eliminate variations in performance due to uneven gap depths of each magnetic head element, and to The object of the present invention is to provide a thin film type multi-element magnetic disk that can obtain a desired magnetic tape contact pressure.

[Means to solve the problem]

In order to achieve the above object, the present invention arranges at least five magnetic head elements on the same substrate in close proximity to each other in the front and back directions of rotation of the edge, and the substrate is placed on a rotating cylinder so that the at least five magnetic head elements In a thin-film multi-element magnetic head in which each magnetic gap portion on the magnetic tape sliding contact surface of the head element is provided with a lip 9 so as to slightly protrude from the outer periphery of the rotary cylinder, five adjacent magnetic heads are The radius of curvature determined by the three points where the magnetic gap depth is zero is defined by those three points.
The radius of curvature R1k is approximately equal to the radius of curvature determined by five points (tips of the gap) on the tape sliding surface of the magnetic gap of the magnetic heads, and the radius of the rotating cylinder iRs.

几>R>　1/4Rs Select so that the following relationship is satisfied.

[Effect]

The operation of the present invention based on the above configuration will be explained with reference to the schematic diagrams of FIGS. 2, 3, and 4.

First, in Fig. 2, 2 is a rotating cylinder, and its outer peripheral surface is also represented, and one magnetic field is connected to this.

Stick out the element! A case will be described in which the rotary cylinder 2 is mounted on the rotary cylinder 2 and a magnetic tape (not shown) is wound around the rotary cylinder 2. The magnetic tape contacts the outer periphery of the rotating cylinder 2 from the left side of the figure, moves away from the outer periphery of the cylinder 2 at a point Q1, and reaches the tip of the magnetic gap of the one magnetic head element (a point on the tape sliding surface) at a point P. It is assumed that the line travels along the straight line Q1P up to the point P, then travels along the straight line PQ2 from the point P to the 92nd point, and again touches the outer peripheral surface 2 at the 92nd point. In this case, the depth of the magnetic gap is about 10-odd μm, which is about 20 μm of the cylinder radius.
It is not shown because it is sufficiently small compared to about m. or,
The core length (the length of the tape sliding surface in the cylinder rotation direction) of the magnetic core (magnetic thin film) having a magnetic gap is also not shown. Line segment PQ1 and line segment PQ2 are tangent lines drawn from point P to cylinder 2.

Therefore, the positional relationship of the arcs determined by the five points Q11PIQ2 is the basis for obtaining a good head touch.

This relationship is based on point Q1. The same holds true when a head adjacent to Q2 is placed so that the tip of its magnetic gap (the gap position of the tape sliding surface) is placed (when magnetic gaps are placed at three points Q' and P*Q2, respectively). Here, Ql
, p, and Q2 as the first
．． Second. and a third magnetic gear 9p.

5 points Q1 at this time. A circle passing through P#Q2 is uniquely determined, and the radius of curvature R of this circle is determined geometrically.

(0 is the center of circle 2) and the intersection with H10', respectively, 0Q1P = LO'HP = 90', t POQ
1 = 1 PO'H = θ, pentagon PO'H and triangle P
Since they are similar to OQ1 and point H is the midpoint of line segment PQ1, the ratio of line segments 0'P and OP is 1:2. Therefore,
When the radius of the cylinder 20 is R8, the radius of curvature R is R=-(Rs+d). Normally, the cylinder radius R8 is about 201, whereas the protrusion td is about 40 μm, which is so small that it can be ignored, so it is 1/4Rs in R. In Fig. 2, all the arc dots of this circle (center 0') are concave, and the tape contacts with roundness only near the tip of each magnetic gap, and between 912 and PQ2,
It is assumed that the path moves in a straight line. Therefore, if the core lengths before and after each magnetic gear lip are ignored, even if the position of the tip of the first magnetic gap is from Ql, the moved point Q'
1. The curvature of the circle determined by Q2 and the tip P2 of the second magnetic gap is equal to the radius R, and the straight line Q,
Since it is located further outward than I P (PQ2 ), good contact with the tape is maintained. However, as described later, if the first to third magnetic gaps are too close together, mutual crosstalk will occur, so it is necessary to avoid this, and the tape contact pressure for the first to third magnetic gaps should be avoided. Since it is necessary to align them, the position of b1 is near the midpoint of QlP (the intersection of OH and QlF), and the position of g2 is near Q2P.
(Tape contact pressure is inversely proportional to the radius of curvature near the gap when the tape tension is constant.

).

Also, in the above explanation, each magnetic gap is recessed,
Although the tape sliding surface is discontinuous, the tape sliding surface between each magnetic gear rib may have a shape with half a predetermined curvature. The tape is connected to the cylinder 2, the arc and the Q1. It passes through Q7 and the above (approximately the same as 2) and proceeds from the cylinder 2 to the head sliding surface.

/7-\ Between Q2P, preferably from the point of view of crosstalk, Q'I
Alternatively, it may be placed near B2.

FIG. 5 shows a case where three head elements (first, second, and fifth magnetic gap tips) ft are arranged in P, P, and P, respectively. Here, P, Ql, Q2. θ, d are the second
As shown in the figure, J is the midpoint of PViPQl (corresponding to point H in FIG. 2), P is the midpoint of PQ2, and HO is the perpendicular bisector of straight line PP. Initially, as in Figure 2, the tape is connected to the tangent Q1
Assuming that the tape travels approximately along p and PQ2, the tape contact pressure at points P and P is uniquely determined to be zero, and the radius of curvature R of this circle is approximately one-fourth of the pentagonal line segment PQ1. Even if the radius of curvature R is moved to position 4+, c (2 (not shown)), a good contact pressure can be obtained at the half curvature. However, as mentioned above,
In order to reduce crosstalk between heads and to equalize the tape contact pressure for each magnetic gap, it is not desirable to make the gaps too close to each other. Also, in FIG. 5, as in FIG. 2, it is possible to provide a continuous tape sliding contact surface between the first to fifth gaps.

Assuming five points p, p, p, theoretically the above radius of curvature (R=τ
There are positions where the tape can be brought into contact with a radius of curvature smaller than Rs ). However, if you try to equalize the contact pressure for the first to fifth heads with such a small radius of curvature, the pressure between each helide.

In the present invention, the radius of curvature TRs shown in FIG.
Let this be the lower limit.

On the other hand, in FIG. 4, when the first to third magnetic heald gap positions (gap tips) P, P, and P are arranged along the circumference of the cylinder 20, there are five points P.

The radius of curvature R of the circle determined by P and P is equal to the radius R8 of the cylinder 2, and the radius of curvature cannot be made thicker than this.

Therefore, in the present invention, the tips (points on the tape sliding surface) of five adjacent magnetic gaps satisfy Rs>R>T
It is set to satisfy the relationship R8, thereby applying a required uniform tape contact pressure to each magnetic head.

Furthermore, as an important feature of the present invention, the above relationship is satisfied not only at the three points at the tip of the magnetic gap but also at the three points where the magnetic gap depth is zero.

As a result, the magnetic gap depth h of each magnetic head becomes uniform, and the characteristics become uniform. Furthermore, since the magnetic gap depth is uniform, the life of the head due to wear of the tape sliding surface of the head is also constant. The fifth head does not wear out before the second head, and the life of the fifth head can be extended.

Strictly speaking, in order to equalize the gap depth, the radius of curvature at the gap depth of zero is the gap depth h(
The radius of curvature at the tape sliding contact surface must be made smaller by the dimension, but the gap depth is usually about 10-odd micrometers, which is extremely small compared to the radius of cylinder 2 (about 20-degrees). , it is safe to say that the radii of both convexities are almost equal.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

1f'i thin film type multi-element magnetic head, consisting of three magnetic head elements 3α, 5h, 5c, each magnetic head element 3α* 3h* 5' is arranged adjacent to each other on the same substrate, and the tape The sliding surface 6 continuously constitutes one surface. 4α, ah, aC are each magnetic head element 3
α.

5b, 5C points of zero magnetic gap depth, 4 are 5 points 4
α.

It is a rotating cylinder on which a two-layer thin film magnetic head 1 is mounted and has a circular arc defined by 4b and 4c.

In the case of this embodiment, the radius R8 of the cylinder 2 is 21 m.

The radius of curvature R of the arc 4 at the point where the gap depth of each head element 5α to 5C is zero is 10, and the gap depth is 15.
Processed so that they were aligned to about μm. The gear lip spacing of each of the five heads is 1.0 cod.

To make the thin-film magnetic head of this embodiment, magnetic head elements 3α, 5b, and ``e'' are arranged on a substrate using thin-film technology. At this time, a point 4α where the magnetic gap depth becomes zero is
, 4A, and 4C are arranged on a preset radius of curvature R. The thin film magnetic head thus prepared is polished so that its front surface becomes a tape sliding surface with a radius of curvature R (for example, the thin film magnetic head is placed on a rotating body with a radius of approximately R) and polished. As a result, the magnetic gap depth is 4α, 4h.

You can make something that has all the 4Cs. In this way, when forming a magnetic thin film, by determining the zero gap depth point so that it has a preset radius of curvature, the gap depths can be easily made uniform.

In the case of this example, the gap depth was reduced by about 5 μm, and the variation in reproduction output was reduced by about 2 db, compared to those produced by the conventional technique. Furthermore, by making the gap depth uniform, the head life was also extended by 500 hours. Although the structure of the head is simplified in the figure, the present invention can be applied to other types of structures as well. A magnetic head 5α with five tape sliding contact surfaces 6.

5h and 5c are shown as being continuous, but a recess is provided between these heads 5α, 5A, and 5c,
It can also be applied to those in which the tape sliding surface 6 is discontinuous.

FIG. 5 shows another embodiment of the invention. In this example,
Four magnetic head elements 4α are provided on the same substrate.

4h, ac, and ad, and magnetic head elements 4a,
4h, 4c gap depth zero point PI, P2.
Ps radius of curvature R4-9m, magnetic head element 4A, 4
1? , 4d, the gap depth is zero at point P2. P3. P
The radius of curvature R of the arc 4 determined by 4 was set to 11. In this case, the radius of the cylinder 20 is 21 mm, and the distance between adjacent magnetic head elements is 0.8 mm.

Note that when the number of head elements in a multi-element magnetic head is four or more, the radii of curvature determined by the zero gap depth position of five adjacent magnetic heads may be the same or different. . In other words, it may be determined based on conditions that optimize the head height.

〔Effect of the invention〕

As detailed above, according to the present invention, in a thin film multi-element magnetic head in which at least five magnetic head elements are formed on the same substrate and mounted on a rotating cylinder, three adjacent The radius of curvature of the zero gap depth point of the magnetic head elements is made almost the same as the radius of curvature of the gap tip (tape sliding surface) of these magnetic herad elements, so the gap depths of each magnetic herad element are the same. As a result, variations in characteristics do not occur, and a longer life can be achieved.

Further, by setting the radius of curvature to the radius of the rotating cylinder or a quarter of the radius of the rotating cylinder, excellent effects can be achieved, such as making it possible to equalize the tape contact pressure for each magnetic hept under the best conditions. .

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of an embodiment of the thin-film multi-element magnetic head of the present invention, and FIGS. 2, 5, and 4 are schematic diagrams illustrating the operation of the thin-film multi-element magnetic head of the present invention. 5 is a schematic plan view of another embodiment of the present invention, and FIG. 6 is a plan view of a conventional thin film magnetic head. DESCRIPTION OF SYMBOLS 1... Thin film type multi-element magnetic head, 2... Rotating cylinder, 5α, 5A, sc, 5d... Magnetic head element, 4... Circle passing through the position of zero gap depth, 4α,
4A, 4c, 4d... Point with zero gap depth, 5α
, 5b...magnetic gap, 6...-tape sliding contact surface, 7... straight line passing through the position of zero gap depth. 1st mouth 2nd place Akira 3rd place 4th sentence 85th concave 4th place

Claims (1)

[Scope of Claims] 1. At least three magnetic head elements are arranged close to each other in the head rotation direction on the same substrate, and the substrate is placed on a rotating cylinder, and the magnetic gap portion of the magnetic head element is aligned with the rotating cylinder. In a thin film multi-element magnetic head mounted so as to protrude from the circumferential surface of the magnetic head, the radius of curvature determined by three points at which the magnetic gap depth of three adjacent magnetic head elements becomes zero is defined as the radius of curvature of the three adjacent magnetic head elements. The radius of curvature R is set to be approximately equal to the radius of curvature determined by three points on the tape sliding surface of the magnetic gap, and when the radius of the rotating cylinder is R_s, the radius of curvature R is set to satisfy the relationship R_s>R>1/4R_s. A thin-film multi-element magnetic head characterized by being selected for.