JP2539334Y2 - Shige head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic head used for a VTR or the like.

[Outline of the invention]

In the present invention, in a magnetic head having a magnetic gap and a magnetic core made of ferrite and provided with a winding window, a length of a metal magnetic film formed in a magnetic gap portion extending to a slope in the winding window is set. The magnetic characteristics are improved by selecting 50 to 220 μm.

[Conventional technology]

Known magnetic heads include a ferrite head, a metal head (laminate head), a metal in-gap head, an inductive thin film head, and the like. Recently, VTR
With higher image quality and higher frequency bands such as digital VTRs, there is a strong demand for higher efficiency magnetic heads. In the conventional magnetic head, the structure of the magnetic head is determined in terms of manufacturing efficiency (speed, workability). FIG. 12 shows a structural example of a conventional metal in-gap head for 8 mm VTR. This magnetic head (1) is composed of a pair of ferrite core halves (2) and (3), and is made of sendust, Fe-Ru-Ga-Si sendust-based crystal alloy, etc. in parallel to the surface on which the magnetic gap g is formed. A metal magnetic film (not shown) is formed, a winding window (5) is provided at the center of the head chip (4), and a winding guide groove (6) is provided on each side. The winding window (5) has a substantially triangular pointed portion (7) having a top at a position where the gap depth is zero and a substantially quadrangular portion (8) continuous with the same width at the base.
Is formed. The winding window (5) in this example has a so-called double-window structure formed over both core halves (2) and (3). The head chip width a in the sliding direction is 1.9 mm, the head chip height b is 1.8 mm, the height c of the winding window (5) is 750 μm, the width d of the base is 500 μm, and the apex angle of the sharp part is as follows. θ is 90 °. This metal-in-gap head (1) has a high saturation magnetic flux density Bs
With the use of the metal magnetic film described above, saturation recording of a high coercive force Hc tape (metal tape, vapor deposition tape, etc.) is enabled.

On the other hand, the metal-in-gap head is not exactly matched due to the butting accuracy of the core halves (2) and (3) as shown in FIG. In addition, the metal magnetic film is formed on the entire butted surface including the inner surface of the winding groove after forming a winding groove of the same shape in each core half block for manufacturing. By the way, since the wettability of the fusion glass and the metal magnetic film is poor, a technique such as mask sputtering is used so that the metal magnetic film does not adhere in the winding groove. As shown in the figure (enlarged view), a metal magnetic film (9) is formed over a considerable area in the winding window (5), and its length is the length L ₁ of the slope portion of the winding window (5) = It is about 354 μm.

[Problems to be solved by the invention]

In the structure of the magnetic head (1) shown in FIG. 12, there is a problem that the winding space is too large and the reproducing efficiency of the magnetic head is deteriorated.

In the metal in-gap head (11) shown in FIGS. 13 and 14, the thermal expansion coefficients of the metal magnetic film (9) and the ferrite core halves (2) and (3) are each 150 × 10 ^-7 /
Since there is a large difference of about 110 ° ^C./° C., 110 × 10 ⁻⁷ / ° C., thermal stress causes deterioration of magnetic properties, leading to deterioration of reproduction efficiency.

In view of the above, the present invention provides a magnetic head which optimizes recording efficiency and reproduction efficiency by specifying the shape of a winding window and can secure a winding space.

Another object of the present invention is to provide a magnetic head in which the length of a metal magnetic film in a winding window of a metal-in-gap head is controlled to improve reproduction efficiency and recording efficiency.

[Means for solving the problem]

The present invention relates to a magnetic head in which a winding window (5) or (25) is provided in a magnetic core made of ferrite having a magnetic gap g and a winding of a metal magnetic film (9) formed in a magnetic gap portion. The length extending to the slope in the line window (5) or (25) is selected to be 50 to 220 μm.

[Operation] In the present invention described above, the length of the metal magnetic film (9) formed in the magnetic gap portion extending to the slope portion in the winding window (5) or (25) is selected to be 50 to 220 μm. As a result, the contact area between the metal magnetic film (9) and the ferrite core is reduced, so that the thermal stress is reduced and the deterioration of the magnetic properties due to the inverse magnetostriction effect is reduced, and the reproduction efficiency and the recording efficiency are relatively improved. .

〔Example〕

Hereinafter, embodiments of the magnetic head according to the present invention will be described with reference to the drawings.

FIG. 1 shows a reference example of the magnetic head according to the present invention. In the same figure, (21) is a pair of ferrite core halves (22) facing the tape sliding surface (24) and forming a magnetic gap g.
And (23) a magnetic core or head chip, (25)
Is a double window type winding window extending over the core halves (22) and (23) formed at the center of the head chip (21), and (26) is a winding window formed on both sides of the head chip (21), respectively. It is a line guide groove. In this example, in particular, the winding window (25) is provided with a triangular pointed portion (2
7) to be formed into a shape composed of the wide portion of the square (28) having a width d ₂ than the width d ₁ of the base continuously in its bottom.
Furthermore, the apex angle θ of the sharp portion (27) of the winding window (25) is set to 60 °.
± 5 ° and the length l of the sharp part (27) is 15
Select 0 μm or more. The length L of the winding guide groove (26)
₂ is 650 μm or less, and depth t is 200 μm or less.

As another example of the dimensional relationship, the head chip width a is 1.9 mm and the head chip height b is 1.8 m, as described above.
m, the height c of the winding window (25) is 750 μm, and the width d ₂ of the wide portion (28) of the winding window (25) is 500 μm. Other, width d ₂ of the coil window eg wide portion as the dimension of (25) (28) 400
μm, the height e of the wide part (28) is 500 μm, and the sharp part (2
The height l of 7) can be selected within an effective range, such as 150 μm.

According to the magnetic head (30) having such a configuration, the winding window (2
By making the shape of 5) a shape consisting of a triangular pointed part (27) and a continuous quadrangular wide part (28), and the vertex angle θ of the pointed part (27) being 60 ° ± 5 °, The recording efficiency and the reproduction efficiency can be optimized. Moreover, by making the length 1 of the pointed portion (27) 150 μm or more and bringing the wide portion (28) closer to the tape sliding surface (24),
The winding space can be secured without deteriorating the optimum recording efficiency and reproduction efficiency, and the same working efficiency as that of the conventional type can be obtained.

That is, FIG. 2 shows the relationship between the reproduction efficiency η / √L converted to the reproduction efficiency η per inductance L and the vertex angle θ of the winding window (25), and FIG. 3 shows the relation between the recording magnetic field and the vertex angle θ. Is shown. These simulations were performed by the finite element method. From the results shown in FIGS. 2 and 3, it is recognized that there is an optimum value for both the reproduction efficiency and the recording efficiency when the apex angle θ is around 60 °. By the way, when the apex angle θ is around 60 °, when the winding window structure shown in FIG. 12 is used, the winding space is greatly reduced as compared with the conventional type (apex angle θ = 90 °), and the working efficiency is deteriorated. On the other hand, in FIG. 4, the magnetic head (3
0), the rectangular wide part (2
8) The reproduction efficiency and the recording efficiency were obtained using the length e as a parameter. The horizontal axis is the length 1 of the remaining pointed portion (27). As is apparent from FIG. 4, when the remaining length 1 of the inferior portion (27) of the winding window (25) becomes 150 μm or less, the recording and reproducing efficiency sharply decreases. As a result, in the present configuration, it is possible to make the winding substantially close to the tape sliding surface (24) by bringing the wide portion (28) as close as possible to the tape sliding surface (24). The efficiency is improved by the change, and at the same time, the winding space is secured.

The magnetic head according to the present embodiment can be applied to a ferrite head, a metal head, a metal in gap head, and the like.

Further, the magnetic head of the present embodiment can also be applied to a case where the core halves are joined with a slight shift as shown in FIG. Furthermore, although the above example was applied to a double-window type winding window (25), it can also be applied to a single-window type winding window in which a winding groove is formed in only one of the core halves. Angle is 55 ° ± 5 ° and length l
Can be 150 μm or more.

5 to 7 show an embodiment of the metal in gap head according to the present invention. In each drawing, the same reference numerals are given to portions corresponding to FIGS. 13 and 14 described above, and redundant description will be omitted. The embodiment of FIG. 5, in the magnetic head having a magnetic gap length L ₁ of the inclined surface portion to the head chip (4) made of ferrite having a g is the usual 354μm winding window (5), the magnetic gap extending the inclined surface portion of the winding window (5) of the metal magnetic film from g (9) the length L ₃ 50
220220 μm.

The embodiment of Figure 6, the length L ₁ of the inclined surface portion of the winding window of the head chip (4) (5) and 50～220Myuemu, metal magnetic layer from the magnetic gap g along the entire length of the inclined surface portion (9 ) Is extended.

In the embodiment shown in FIG. 7, the head chip (4) has the first
Shape having a wide portion (28) of the part (27) pointed as shown in the figure, the sharpness of the slope portion (27) the length L ₁ from 50 to 22
A winding window (25) having a thickness of 0 μm is formed, and the metal magnetic film (9) is extended from the magnetic gap g over the entire length of the slope.

FIG. 8 shows the relationship between the length in the winding window of the metal magnetic film (9) of the metal in-gap head, and the reproduction efficiency and the recording efficiency. Curve (I) is the recording efficiency, and curve (II) is the reproduction efficiency. This is the result of analysis using the finite element method (FEM). According to FIG. 8, when the length of the metal magnetic film is shorter than 50 μm, the effect of the metal magnetic film decreases, and the reproduction efficiency and the recording efficiency deteriorate. Further, when the length of the metal magnetic film is increased so as to exceed 220 μm, a region where the magnetic characteristics are deteriorated due to stress caused by a difference in thermal expansion increases.

According to each of the magnetic heads (32), (33) and (34) described above, the length of the metal magnetic film (9) on the slope portion in the winding window (5) or (25) is selected to be 50 μm to 220 μm. As a result, the characteristics can be exhibited without deteriorating the original reproduction efficiency and recording efficiency of the metal-in-gap head. That is, since the contact area of the metal magnetic film in the winding window with the ferrite core is reduced, thermal stress is reduced, deterioration of magnetic properties due to the inverse magnetostriction effect is reduced, and efficiency is relatively improved. This also serves to reduce the size of the winding windows (5) and (25) at the same time, thereby improving the reproduction efficiency by reducing the magnetic path length.

On the other hand, the structure of the magnetic head emphasizes the easiness of the manufacturing process. For example, as shown in FIG. 9, both core halves (2)
And (3) are joined. The gap y in the gap depth between the left core half (2) and the right core half (3) is called a murad. In a conventional head, the amount of unevenness y is determined to be about 40 μm ± 20 μm in consideration of mass productivity. However, as the magnetic head, the angle of the winding window (5) near the gap depth of zero (mullad portion) is halved. I was As a result of simulating the reproduction efficiency (reproduction efficiency η / √L in terms of inductance) by using the amount of murrard as a parameter using the finite element method, as shown in FIG. In), there is almost no change in the regeneration efficiency. However, the mud amount is 10μ
m, the leakage (40) of the magnetic flux near the gap depth of zero is reduced. As a result, the inductance is reduced and the regeneration efficiency per inductance (η / √L) is improved. As described above, in the present reference example, as shown in FIG. 10, a pair of core halves (2) and (3) are butt-joined to each other, The murad amount y is set to 10 μm or less. According to the magnetic head (42), it is possible to provide a magnetic head in which the magnetic flux leakage near the gap depth of zero is reduced and the reproduction efficiency per number of turns is improved. This technique can be applied to a ferrite head, a laminating head, a metal in gap head, and the like.

[Effect of the invention]

According to the magnetic head of the present invention, in a magnetic head made of ferrite having a metal magnetic film in a magnetic gap portion,
The length of the metal magnetic film extending to the slope in the winding window is 50μm
By setting the thickness to about 220 μm, the contact area between the ferrite and the metal magnetic film is reduced, the deterioration of the magnetic properties due to the thermal stress due to the difference in thermal expansion coefficient is reduced, and the recording efficiency and the reproduction efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a reference example of the magnetic head according to the present invention, FIG. 2 is a graph showing the relationship between the apex angle of the winding window and the reproduction efficiency, and FIG. 3 is the apex angle of the winding window and the recording efficiency. FIG. 4 is a graph showing the relationship between the length of the pointed portion of the winding window and the recording and reproducing efficiency, and FIGS. 5 to 7 are front views showing an embodiment of the magnetic head according to the present invention. FIG. 8 is a graph showing the relationship between the length of the metal magnetic film in the winding window and the reproduction efficiency, FIG. 9 is a front view for explaining a conventional magnetic head, and FIG. FIG. 11 is a front view of a reference example of a magnetic head in which reproduction efficiency is improved, FIG. 11 is a graph showing a relationship between a murad amount and reproduction efficiency, FIG. 12 is a front view showing an example of a conventional magnetic head, and FIG. FIG. 14 is a plan view for explaining a conventional metal-in-gap head and an enlarged view of a main part thereof. (2), (3), (22), and (23) are core halves, (5),
(25) is a winding window, (9) is a metal magnetic film, (27) is a pointed portion, and (28) is a wide portion.

Continuing on the front page (72) Inventor Shoichi Kano 6-5-6 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Magne Products Co., Ltd. (72) Inventor Yoichi Inmaki 6-5, Kita-Shinagawa, Shinagawa-ku, Tokyo No. 6 Sony Magne Products Co., Ltd. (72) Inventor Miho Suzuki 6-5 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Magne Products Co., Ltd. (56) References JP-A-63-142501 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. A magnetic head in which a winding window is provided on a magnetic core made of ferrite having a magnetic gap, wherein the metal magnetic film formed in the magnetic gap portion extends to a slope portion in the winding window. A magnetic head having a length selected from 50 to 220 μm.