JPH0559616U - Arrangement structure of magnetic head for magneto-optical recording - Google Patents

Abstract

(57) [Summary] [Object] To provide an arrangement structure of a magnetic head for magneto-optical recording in which the head is prevented from coming into contact with a resin protective layer formed by a spin coating method as much as possible, and the head life and reliability are improved. A magnetic head for magneto-optical recording in which a resin protective layer is formed by spin coating on the surface of the magneto-optical disk on which a magnetic field is applied and recording is performed with the magnetic field generating core portions of the magnetic head facing each other. With the arrangement structure, the core portion is arranged at a position of about 1 mm or less from the side closest to the outer peripheral edge of the magnetic head body to the disk center side, and
Move the side of the magnetic head body from the disk outer edge to the center.
The structure is so arranged that it can be moved toward the center of the disc from a location 1 mm or more away. As a result, recording / erasing can be performed while avoiding the resin protective layer protruding on the outer peripheral portion of the magneto-optical disk.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an arrangement structure of a magnetic head for magneto-optical recording used in a magneto-optical disk.

[0002]

[Prior Art]

 At present, a rewritable type magneto-optical disk capable of rewriting information has begun to be put into practical use, and in this magneto-optical recording method, a magnetic recording formed on a disk substrate by using a laser beam or a magnetic head. Recording information is written in the layer, and the recording information is read or rewritten.

When such rewriting is performed by an optical modulation recording method, a magneto-optical disk is irradiated with laser light while applying a constant external magnetic field to raise the temperature of the magnetic recording layer and reduce the coercive force. It is necessary to separately perform the erasing operation of aligning the magnetization in a certain direction and the recording operation of irradiating the modulated light corresponding to the write data and causing the magnetization reversal in a part of the recording. In other words, it was necessary to rotate the magneto-optical disk at least twice to perform this work, and it was difficult to rewrite in real time.

Therefore, it has been proposed to perform rewriting by a so-called magnetic field modulation method instead of the above-mentioned optical modulation method. This method uses the same principle as the general magnetic disk recording method. Recording is performed by directly applying a modulating magnetic field with a magnetic head to cause magnetization reversal corresponding to data in the magnetic recording layer. It is a method. As described above, the magnetic field modulation recording method allows overwriting, but on the other hand, a magnetic head that can switch at high speed while applying a large bias magnetic field must be used. There is a problem that it is difficult to manufacture because it has a large drive current and a large reactance.

In view of such circumstances, as a suboptimal measure, a generally used levitation type magnetic head (flying head) is applied to a magneto-optical disk for a fixed magnetic disk device (HDD) and the like. Is proposed. Here, the shape of the magnetic head is approximately 8 × 6 × 1 mmt, and a core portion for generating a magnetic field is provided in the central portion of the side substantially parallel to the radial direction of the magneto-optical disk.

[0006]

[Problems of the prior art]

 By the way, the amorphous alloy layer used for the magnetic recording layer of the magneto-optical disk is inferior in oxidation resistance.Therefore, a protective layer of a non-magnetic inorganic thin film is formed on this layer, and the thickness of 3-20 μm It is common practice to form the resin protective layer by spin coating. That is, while rotating the disk substrate on which the magnetic recording layer is formed, coating is performed with the resin discharged from the dispenser on the disk substrate.

However, at this time, the discharge port of the dispenser is moved from the center side of the disc substrate to the outer periphery side to perform spin coating. However, due to centrifugal force when rotating the disc substrate during coating and surface tension of the resin, As shown in FIG. 4, abrupt change in film thickness occurs on the outer peripheral portion of the disk substrate 4 and a ridge 7 is formed. When recording is performed with the above flying head using such a magneto-optical disk, the magnetic head body collides with the ridge 7 at the time of recording on the outermost circumference of the disk, or, for example, in a 3.5 inch (φ86 mm) magneto-optical disk. The magnetic head itself may protrude from the disk surface when it is tilted, making the flying characteristics of the magnetic head unstable and making it difficult to record or erase data on the outer circumference of the disk, or even cause a head crash. It was a problem.

[0008]

[Means for Solving the Problems]

 Therefore, the present invention focuses on the above-mentioned problems, and aims to prevent the head from contacting the resin protective layer formed by the spin coating method as much as possible to improve the life and reliability of the magnetic head for magneto-optical recording. In order to achieve this purpose, in the present invention, a resin protective layer is applied and formed on the surface of the magneto-optical disk on the magnetic field applying side by a spin coating method to generate a magnetic field for the magnetic head. This is a layout structure of a magnetic head for magneto-optical recording in which the core parts are opposed to each other for recording. We adopted a structure in which the core part was placed at the position, and the side of the magnetic head body was placed so that it could be moved to the center of the disk from a position 1 mm or more away from the outer peripheral edge of the disk toward the center.

[0009]

【Example】

 Hereinafter, embodiments according to the present invention will be described in detail. As shown in FIG. 1, the magnetic head body 1 of the present invention is a composite type in which the slider portion 2 is made of a non-magnetic ceramic material, the magnetic core portion 3 is made of a magnetic material, and the two are joined together. The slider portion 2 is made of a ceramic material such as calcium titanate or barium titanate, and the magnetic core portion 3 is made of a magnetic material in which Mn-Zn ferrite or Ni-Zn ferrite, and a sendust alloy or the like are formed into a thin film.

The main body 1 has a length of about 8 mm, a width of about 6 mm, and a thickness of about 1 mm, and as shown in FIG. 2A, a surface facing a magneto-optical disk (hereinafter, also simply referred to as a disk). The levitation rail 2a and the blade groove 2b are formed on the ridge, and the air flow generated by the rotation of the disk is used to generate a positive pressure on the levitation rail 2a, while the air not useful for levitation is generated in the blade groove 2b. It escapes and the main body 1 is appropriately floated. Arrange the disk so that the side with a length of about 8 mm in the radial direction and the side with a width of about 6 mm in the circumferential direction (the side closest to the outer peripheral edge of the disk) are located. 3 is provided on a side having a length of about 8 mm, and its center is arranged at a position of about 1 mm from the side having a width of about 6 mm to the center of the disc. The size of the magnetic head body is arbitrary, and a magnetic head having a structure without a blade groove may be used.

Next, production of a magneto-optical disk to which the magnetic head of the present invention is applied will be described. As shown in FIG. 3, an optical recording layer 5 was formed on one main surface of a 3.5 inch (φ86 mm) polycarbonate disk substrate 4 by a sputtering apparatus. Here, the optical recording layer 5 is, for example, a first dielectric layer of amorphous yttrium sialon (thickness of about 100 nm), an amorphous Gd-Dy-Fe-based magneto-optical recording layer (thickness of about 200 nm), an amorphous layer. A second dielectric layer of yttrium sialon (about 300 nm thick) and a reflective layer of metallic aluminum (about 100 nm thick) are sequentially laminated. It should be noted that the dielectric layer may not have either one, and may have other known configurations and materials.

Further, a resin protective layer 6 was formed on the optical recording layer 5. That is, a urethane acrylic UV-curable resin (product name SD-301, manufactured by Dainippon Ink & Co., Inc.) was applied by a spin coating device to a thickness of about 10 μm at a distance r = 24 mm from the center of the disc. It was formed and cured by ultraviolet rays so that the hardness after curing was 2 H or more in terms of pencil hardness. In addition to the above resins, various resins such as epoxy type, polyester type, and acrylic type can be used for the resin protective layer 6. If necessary, a solid or liquid lubricant is mixed with the resin to form a magnetic head. The frictional resistance of can be reduced.

At this time, the resin protective layer 6 shows a gentle coating thickness distribution up to r = 24 to 42 mm, but due to the centrifugal force at the time of coating and the surface tension of the resin, r = 42 to 43 mm or so. It was found that the steep ridge 7 was present, and the highest portion thereof was thicker by about 10 μm than the coating thickness of r = 42 mm, for example.

Next, a description will be given of the results of a levitation test using the disk manufactured in this way, under the conditions of a disk rotation speed of 2400 rpm and a head load of 6 g, with various arrangements of the magnetic head 1 with respect to the disk. To do. For comparison with the magnetic head 1 used in the present invention, as shown in FIG. 2B, a conventional magnetic head 10 having a core portion 3 provided in the center was used.

In the magnetic head 1 in which the core portion 3 is provided on the outer peripheral side, the center portion of the core portion 3 can be stably levitated up to the radial position r = 23 to 41 mm of the disk without contacting the disk. With the magnetic head 10 in which 3 was provided in the center of the head width, stable flying was possible without contact up to r = 23 to 38 mm, but when r = 39 mm or more, the head body was placed on the outer periphery of the disk. The ridge 7 formed was touched.

Furthermore, as a result of performing a CSS (contact start stop) test of 15 seconds per cycle under the above conditions at r = 40 mm, the magnetic head 10 in which the core portion 3 is at the center of the head width is about 7,000 times. A head crash occurred, but the head 1 having the core portion 3 provided on the outer peripheral side of the disk did not cause a head crash up to 50,000 times. The CSS test means that the magnetic head loaded on the disk is in contact with it (contact), the disk is rotated at a specified number of rotations (start), and the disk rotates when the magnetic head floats above the disk. It is said that a number of contact → start → stop cycles such as stopping the number (stop) are performed many times (usually about 100,000 cycles).

In the above embodiment, an example using a 3.5 inch (φ86 mm) disk was described, but in the case of a 5 inch (φ130 mm) disk, the position where the protrusion of the resin protective layer starts is r1 = 63.5 to 65 mm. The position r2 of the outermost periphery of the optical recording layer is generally about 61 mm, while in the case of a 3.5-inch disc, r1 = 42 to 43 mm and r2 = 41 mm are common. In order to avoid the magnetic head from coming into contact with the ridge of the resin protective layer and effectively secure the recording area, the position W of the core part should be set approximately at the side of the magnetic head body located on the outer peripheral side of the disk. It can be seen that it should be placed on the center side of the disc at a site of 1 mm or less. The width of the core portion is about 0.2 mm, which is extremely thin, and if the center position is approximately 1 mm or less from the side of the magnetic head body, it can be applied to both disks.

Further, by using the magnetic head having the core portion arranged as described above, if the recording information is written to the center side of the disc from a portion at least about 1 to 4 mm away from the outer circumference side to the center side of the disc, It is easy to write information in the recording area and erase information without waste.

In this embodiment, the composite type is shown as an example of the magnetic head, but as another magnetic head, a so-called monolithic type magnetic head in which the slider portion and the magnetic core portion are integrally formed of the same magnetic material is used. The present invention can be applied to such cases.

[0020]

[Effect of the device]

 As described in detail above, when magnetic field modulation recording is performed on a magneto-optical disk coated with a resin protective layer by the spin coating method, the arrangement structure of the magnetic head for magneto-optical recording of the present invention is adopted. The recording / erasing can be performed while avoiding the raised portion on the outer circumference of the magneto-optical disk, the destruction of the magnetic head can be prevented as much as possible, and the life of the magnetic head can be greatly improved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a magnetic head of an embodiment according to the present invention.

2A is a bottom view of the magnetic head shown in FIG. 1 viewed from the core side, and FIG. 2B is a bottom view of the magnetic head of the comparative example shown in FIG. is there.

FIG. 3 is a cross-sectional view showing a positional relationship between a magnetic head and a magneto-optical disk in an outer peripheral portion of the magneto-optical disk according to the present invention.

FIG. 4 is a cross-sectional view showing a positional relationship between a magnetic head and a magneto-optical disk on an outer peripheral portion of a conventional magneto-optical disk.

[Explanation of symbols]

1 ... Magnetic head main body 2 ... Slider part 3 ... Core part 4 ... Substrate 5 ... Optical recording layer 6 ... Resin protective layer 7 ... Protrusion

Claims (1)

[Scope of utility model registration request] 1. A magnetic recording medium for magneto-optical recording, wherein a resin protective layer is formed by spin coating on the surface of a magneto-optical disk on which a magnetic field is applied, and recording is carried out with the magnetic field generating core portions of a magnetic head facing each other. In the head arrangement structure, the core portion is arranged at a position of about 1 mm or less from the side closest to the outer peripheral edge of the magnetic head main body to the disk center side, and the side of the magnetic head main body is An arrangement structure of a magnetic head for magneto-optical recording, which is arranged so that it can be moved to the center side of the disk from a portion 1 mm or more away from the outer peripheral edge of the disk toward the center side.