JPH01235005A - Magnetic head - Google Patents

Abstract

PURPOSE:To easily obtain a magnetic head which is capable of sufficiently exhibiting the outstanding characteristics thereof even if a system in which two pieces of heads are disposed at a narrow gap spacing by forming a magnetic metallic material on the end face of an I-shaped core opposite to the winding window thereof. CONSTITUTION:A magnetic metallic film 1 consisting of an amorphous alloy or 'SENDUST(R)', etc., is sandwiched by a nonmagnetic substrate 2 consisting of ceramics of a calcium titanate system, etc., to constitute a main magnetic core. The magnetic core consists of a C-shaped core having a winding window 3 and the I-shaped core about 0.2mm length in the traveling direction of a recording medium. These cores are joined by bonding glass 4 via a nonmagnetic film to form the magnetic gap 5. The magnetic metallic film 6 is formed via a nonmagnetic insulating film on the side face of the I-shaped core on the side opposite to the winding window thereof. The magnetic metallic material 6 formed in the end part is thereby added in parallel to the magnetic path even if the length L of the I-shaped core is short and, therefore, the magnetic resistance of the I-shaped core part is lowered and the degradation in reproduction efficiency is prevented. The magnetic head capable of recording and reproducing signals with high efficiency is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a highly efficient magnetic head suitable for a VTR having a special playback function and a tape speed switching function.

Conventional technology Recently, VTRs used for recording and playing back video have become common, with special playback functions, and the number of video heads installed in one VTR has increased from the traditional two to four to eight. There is. In this case, one head window on the cylinder has two
For example, a combination of a recording/reproducing head and a special reproduction head, or a standard tape speed head and a low tape speed head is used. In such a case, the distance between the gaps between the two heads is determined to be a certain interval mainly based on the relationship between the horizontal synchronizing signals. For example, in one example of the VH8 system, this interval is a distance equivalent to twice the interval of horizontal synchronizing signals, that is, about 0.74 mm. Therefore, as shown in Figure 2, the video head has a configuration in which the length L of one core in the recording medium running direction is shorter than the other core, and considering the space for the winding, the length L is shorter than that of the other core. is approximately 0.2 mm. By the way, conventional V
In devices for recording and reproducing high frequency signals such as TRs, heads using ferrite materials with low high frequency loss have generally been used. In the case of a ferrite head, the entire core width is made of ferrite except for the area near the magnetic gap, so even if the length mentioned above is short, the entire core width can be used as a magnetic path, so the drop in head efficiency is not so large. do not have.

Problems to be Solved by the Invention Recently, high image quality is required for VTRs, and there is a trend toward increasing the coercive force of video tapes in order to improve short wavelength characteristics. A metal magnetic film 1 with a high saturation magnetic flux density as shown in Fig. 3 is desired.
A structure in which the magnetic material is sandwiched between non-magnetic materials 2 is used.

However, in the case of a head with such a structure, it exhibits extremely high efficiency characteristics in a normal shape, but if the length L of the I-shaped core is small (as mentioned above), the reproduction efficiency may drop sharply. Okay. Figure 4 shows the change in head output when the length of the ■-type core is changed in the head shown in Figure 3. The head used in the experiment has a length of I-type core. The other specifications are almost the same, the relative speed is 5.8 m/s,
The frequency is 7MHz. As you can see from this figure, the third
In the head with the structure shown in the figure, the length of the ■-shaped core is 0.2
When it becomes about mm, the head output sharply decreases. The degree of this decrease becomes greater as the track width of the head becomes smaller.

Means for solving the problem The main magnetic core has a structure in which a metal magnetic film is sandwiched between non-magnetic substrates, and the length of the ■-shaped core with no winding window across the magnetic gap in the recording medium running direction is the length of the winding. In a magnetic head having a structure shorter than the length of a C-shaped core having a window, a metal magnetic material is formed on the end face of the ■-shaped core opposite to the winding window.

Effect With the above-mentioned configuration, the length L of the I-shaped core is short (although the metal magnetic material formed at the end is applied in parallel to the magnetic path, so the magnetic resistance of the I-shaped core part can be lowered, reducing the reduction in regeneration efficiency. This provides a magnetic head that can record and reproduce signals with high efficiency.

Embodiment A perspective view of an embodiment of the present invention is shown in FIG. In the figure, reference numeral 1 denotes a metal magnetic film such as an amorphous alloy or Sendust alloy, which is sandwiched between non-magnetic substrates 2 such as calcium titanate ceramics to form a main magnetic core. The magnetic core consists of a C-shaped core with a winding window 3 and an I-shaped core with a length of about 0.2 mm in the recording medium running direction, which are opposed to each other with a non-magnetic film in between and bonded by a bonding glass 4 to form a magnetic core. A gap 5 is formed. Further, on the side surface of the I-shaped core opposite to the winding window, a metal magnetic film 6 made of an amorphous alloy, sendust alloy, etc. is formed with a non-magnetic insulating film made of 5iOz or the like interposed therebetween. If a metal magnetic film with a thickness of about 45 μm is formed on an I-type core with a metal magnetic core width of 30 μm and a chip width of 130 μm by rubbing such a structure, the magnetic resistance of the ■-type core will be the same as that without the metal magnetic film. Even if the length of the type 1 core becomes about 0.2 mm, the decrease in head output that has been seen in the past almost disappears. Note that if the metal magnetic film is exposed at the end of the head, it will create a pseudo gap and generate unnecessary signals, so it is desirable to shave off the end so that the metal magnetic film 11 does not come into contact with the tape.

The manufacturing method for such a magnetic head is to first form a metal magnetic film on a non-magnetic substrate by sputtering, stack multiple sheets, adhere them with crystallized glass, etc., and cut them. This creates a pair of core blocks in which the core blocks are alternately stacked. One of the pair of core blocks forms a winding window to form a C-shaped core block, while the other remains in the same shape as a ■-shaped core block. Thereafter, the gap surfaces of both core blocks are polished to a mirror surface, a non-magnetic thin film such as glass is formed to a predetermined thickness by sputtering, and the core blocks are butted together and bonded with bonding glass. After that, the type 1 core side is cut and polished to a length of approximately 0°2 mm. Next, a metal magnetic film is formed on the surface of this polished I-type core by sputtering. Thereafter, the magnetic head shown in FIG. 1 can be manufactured by cutting this to a predetermined thickness and wrapping the front surface with tape. In particular, when using an amorphous alloy, there are restrictions on heat treatment, so the metal magnetic film formed on the side surface of one core has a lower saturation magnetic flux density than the magnetic core, and even if annealed at a relatively low temperature, it has high magnetic permeability. It is better to choose the composition that is obtained.

In addition, when particularly high frequency characteristics are required, it is preferable that the metal magnetic films constituting the track width are laminated via an insulating layer such as SiO2 and divided into thicknesses that take into account eddy current loss. In this case, be careful not to short-circuit the laminated film with the metal magnetic film formed on the side surface of the I-core at the interface with the I-core! T! ! Better characteristics can be obtained by forming the edge layer and forming the metal magnetic film itself formed on the end face into a laminated structure.

Effects of the Invention According to the present invention, it is possible to easily create a magnetic head that can fully bring out the performance of a high coercive force medium and can fully exhibit its characteristics even in a system in which two heads are arranged with a narrow gap. That's what you get.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head according to an embodiment of the present invention, FIGS. 2 and 3 are perspective views of a conventional magnetic head, and FIG.
This figure is a diagram showing the relationship between the length of the I-shaped core in the conventional magnetic head shown in FIG. 3 and the head output. 1...Metal magnetic film, 2...Nonmagnetic substrate, 3...
...Wire-wound window, 4...Bonding glass, 5...
・Magnetic gap, 6...Metal magnetic film, 7...Oxide bow A, magnetic material. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 5 Figure 4 Figure I Bore Invasion (m-t)

Claims (3)

[Claims] (1) The main magnetic core has a structure in which a metal magnetic film is sandwiched between non-magnetic substrates, and an I
In a magnetic head having a structure in which the length of the recording medium running direction of the type core is shorter than the length of the C type core having a winding window, the I
A magnetic head characterized by having a structure in which a metal magnetic material is formed on an end surface of a mold core opposite to a winding window. (2) Claim 1, characterized in that the metal magnetic material formed on the end face of the I-shaped core opposite to the winding window is made of a multilayer film in which metal magnetic thin films and insulating thin films are alternately laminated. The magnetic head described. (3) The magnetic head according to claim 1 or 2, wherein the main magnetic core is a multilayer magnetic core in which metal magnetic thin films and insulating thin films are alternately laminated.