JPH03142701A - Head for magneto-optical disk - Google Patents

Abstract

PURPOSE:To improve recording characteristics by providing a magnetic field generating part holding plate which consists of a resin film and holds a magnetic field generating part near a laser beam focusing position in such a manner that the laser beam is not shielded and bringing the magnetic field generating part near to the recording medium without impairing the recording medium. CONSTITUTION:An optical head 20 contg. at least a laser light source 5 and an optical system 6 which focuses the laser beam emitted from the laser light source 5 to the prescribed position on the recording medium 1 positioned on the outer part and the annular magnetic field generating part 24 which has a hole 21a to obviate the shutting of the laser beam in the central part are provided. The magnetic field generating part holding plate 21 made of the resin film which is fixed to the optical head 20 and holds the magnetic field generating part 24 near the laser beam focusing position so as not to shield the laser beam is provided. Even if the magnetic field generating part 24 and eventually the front end of bellows come into contact with the recording medium, the bellows part 21c absorbs the contact force thereof and, therefore, the above-mentioned contact part easily retreats and does not break the recording medium. The head for magneto-recording disks having the good recording characteristics is obtd. in this way.

Description

[Detailed Description of the Invention] [Summary] Regarding a head used in a magneto-optical disk device using a magnetic field modulation override method, the present invention is used in a magneto-optical disk device for the purpose of improving recording characteristics without damaging the recording medium. an optical head for a magneto-optical disk using a magnetic field modulation method, which includes at least a built-in laser light source and an optical system that focuses the laser light emitted from the laser light source onto a predetermined position on an externally located recording medium; A ring-shaped magnetic field generating section is provided with a hole in the center that does not block the laser beam, and the end portion is fixed to the optical head, and the magnetic field generating section is positioned near the laser beam focus position so that the laser beam is not blocked. It consists of a magnetic field generating part holding plate made of a resin film that is held in place.

[Industrial application field]

The present invention relates to a magneto-optical disk device, and more particularly to a head for a magneto-optical disk in which recording characteristics are improved by bringing a low impedance magnetic coil closer to the recording medium without damaging the recording medium.

The magneto-optical recording method records predetermined information on the recording medium by irradiating a laser beam onto the surface of the recording medium located within a magnetic field.
There are two methods: the optical modulation override method, which uses a constant magnetic field strength and flashes a laser beam, and the magnetic field modulation override method, which modulates the magnetic field strength while irradiating a continuously oscillating laser beam. Although the modulation method requires the direction of the magnetic field to be rapidly reversed in accordance with the information signal, it has the advantage of not requiring an optical modulation system because the laser beam is continuously irradiated.

In particular, with this magnetic field modulation method, the closer the magnetic field generator that applies the magnetic field to the recording medium is, the closer the magnetic field generating part that applies the magnetic field to the recording medium is, the higher the required strength of the magnetic field can be obtained with a low-impedance magnetic coil. Inversion becomes easy and recording characteristics such as improved recording density can be improved.

Therefore, how to bring the magnetic field generating section close to the recording medium has become a major issue.

[Conventional technology]

FIG. 2 is a conceptual diagram showing a configuration example of a fixed type magnetic field modulation type head, and FIG. 3 is a conceptual diagram showing a configuration example of a floating type magnetic field modulation type head. Note that all figures are shown in side views.

In FIG. 2, a recording medium 1 is formed on one side of a substrate 2 made of acrylic resin or the like, and is configured to rotate in the thickness direction of the paper surface, for example, about a rotating shaft 2a.

Further, an electromagnet 4 is built into the magnetic field generating section 3 fixedly arranged close to the surface of the recording medium 1.

On the other hand, on the other side of the recording medium l forming surface of the substrate 2, a laser light source 5 and an optical system 6 for focusing the laser light emitted from the light source 5 onto the recording medium 1 are provided at a position corresponding to the magnetic field generating section 3. An optical head 7 having at least a built-in is disposed therein.

Therefore, while rotating the recording medium 1, an input signal is input to the electromagnet 4, and the electromagnet 4 generates a magnetic field that reverses at high speed in the thickness direction of the recording medium 1 while emitting a predetermined laser beam @ the surface of the recording medium. When irradiated with the laser beam, information corresponding to the input signal can be continuously recorded in the thickness direction of the recording medium l at the irradiation position of the laser beam (region a in the figure).

Note that in order to reproduce the information recorded on the recording medium 1, when the information recording area is irradiated with a laser beam, the laser beam reflected from the area is detected by a detection system (not shown) built in the optical head 7. It is designed to be detected and executed.

Such a fixed type magneto-optical disk head has the advantage of a simple overall structure, but in order to avoid contact between the rotating recording medium l and the magnetic field generating section 3, the magnetic field generating section 3 is separated from the recording medium l by at least 0. 5-1, they must be separated by about On+m, and a large magnetic coil is required to secure a magnetic field of the strength necessary for recording, and the impedance increases accordingly, making it difficult to reverse the magnetic field at high speed. However, it has the disadvantage of limiting high-density recording.

The flying type head for magnetic field modulation system shown in FIG. 3 is designed in consideration of such drawbacks, but the recording medium 1 and substrate 2 shown in the figure are the same as those shown in FIG. 2.

Further, a magnetic field generating section 10 located close to the surface of the substrate 2
1 has a structure in which a coil 12 wound around a ferrite shaft 11 and a slider 13 made of a non-magnetic material are integrated. For example, the slider 13 follows a guide shaft 14 fixed in a direction perpendicular to the surface of the recording medium l. It is configured to be able to move slightly only in the direction perpendicular to the surface of the recording medium 1.

Note that on the other side of the surface on which the recording medium l is formed, the magnetic field generating section 10
The optical hand door disposed at the corresponding position is of the second direction or the like.

In such a configuration, for example, when the recording medium 1 is rotated with the slider 13 set so that the recording medium facing surface 13a is separated from the surface of the recording medium 1 by several μm, the magnetic field generating portion 1O and the recording medium 1 are rotated. A positive pressure (a force in the direction of pushing up the magnetic field generating section 10) is generated between the magnetic field generating section 10 and the recording medium 1, thereby causing the entire magnetic field generating section 10 to float.

Therefore, by appropriately setting the weight of the magnetic field generating section IO, the gap δ (for example, 1
0 am) can be maintained in a stable state.

This means that a magnetic field of the necessary strength can be secured with a smaller magnetic coil, that is, a coil with low impedance, compared to the case shown in Figure 2, and as a result, the magnetic field can be easily reversed at high speed, and the second Higher density recording can be achieved than in the case shown in the figure.

However, in this case, the gap between the recording medium 1 and the magnetic field generating section 10 is extremely small compared to the case shown in FIG.
The surface precision or waviness of the recording medium 1, which was not a problem in the figure, or dust adhering to the surface of the recording medium 1 may cause the two to come into contact and damage the recording medium 1.

[Problem to be solved by the invention]

Conventional magneto-optical disk heads have the problem that a fixed type head requires a coil with high impedance, which limits high-density recording, and a floating type head requires a coil with high impedance. Although high-density recording can be achieved because a low-impedance coil can be used, there is a problem in that the recording medium may be damaged.

[Means to solve the problem]

The above problem is caused by a magnetic field modulation type magneto-optical disk head used in a magneto-optical disk device. an optical head having at least a built-in system; a ring-shaped magnetic field generating section having a hole in the center that does not block the laser beam; This problem is solved by a magneto-optical disk head that includes a magnetic field generating section holding plate made of a resin film that holds the laser beam in the vicinity of the focus position so that the laser beam is not blocked.

[For production]

If the magnetic field generating section is configured so that the surface of the recording medium is not damaged even if it comes into contact with the recording medium, the magnetic field generating section can be brought close to the surface of the recording medium.

In the present invention, bellows made of at least three or more resin films are provided at the tip of the optical head facing the recording medium, and the magnetic field generating section is held at the tip of each bellows.

In this case, even if the magnetic field generating section and the bellows tip come into contact with the recording medium, the bellows absorbs the contact force, so the contact section does not easily retreat and damage the recording medium.

Therefore, it is possible to bring the magnetic field generating section close to the recording medium in the same way as a conventional flying type head without damaging the recording medium, and it is possible to obtain a magneto-optical disk head with good recording characteristics.

〔Example〕

FIG. 1 is a detailed illustration of the present invention, in which (A) is an enlarged side sectional view of the main part, and (B) is a plan view showing the tip section when cut along arrows a to a''. .

In Figures (A) and (B), the second
As in the case of FIG. 2, the illustrated substrate 2 is configured to rotate in the thickness direction of the paper surface about a rotating shaft 2a.

Further, the optical head 20 disposed facing the rear side of the recording medium 1 has at least a laser light source 5 therein and focuses the laser light emitted from the light source 5 onto the recording medium 1, as explained in FIG. It has a built-in optical system 6.

Further, the reference numeral 21 attached to the tip end of the optical head 20 on the side of the recording medium 1 is a magnetic field generating part holding plate made of a polygon resin film with a thickness of 20 to 30 tI11, and in particular, the shape is at least the same as that of the above-mentioned laser. Three or more (four in the figure) bellows 21c with a width of about 5n+m are formed from a circular part 21b with a hole 21a in the center having a diameter that does not block the luminous flux of light.
The bellows 21c are formed radially at equal intervals, and the bellows 21c is attached to the optical head 2o by gluing, etc. at a predetermined position on the external side wall surface of the optical head 20 at the free end side of each bellows 21c bent in one direction. I am trying to fix it by the following means.

The magnetic field generating section holding plate 21 is made of a polyimide resin film because this resin has excellent dimensional stability and abrasion resistance.

Further, on the surface of the optical head 20 of the circular portion 21b of the magnetic field generating portion holding plate 21, a soft magnetic ring 22 made of iron (Fe) or the like having a hole having the same diameter as the hole 21a and the soft magnetic material are provided. A magnetic field generating section 24 composed of a magnetic coil 23 wound so as to be inscribed in the outer diameter portion of the ring 22 is adhesively fixed with their central axes aligned.

In such a configuration, the magnetic field generating section 24 is suspended from the optical head 20 by a plurality of bellows 21c.
If even a slight external force is applied from the 1 side, the external force will cause the bellows 21
The magnetic field generating portion 24 itself easily retreats as it is absorbed by the portion c.

Therefore, when the recording medium 1 is rotated with the optical head 20 set so that the circular part 21b of the magnetic field generating section holding plate 21 is separated from the surface of the recording medium 1 by, for example, several μm, as explained in FIG. As such, positive pressure is generated between the recording medium 1 and the circular portion 21b, and the circular portion 21b is stabilized by maintaining a constant distance (for example, 10 μm) from the surface of the recording medium 1.

This means that the magnetic field generating section 24 is stabilized at a position approximately 20 to 30 uI11 away from the surface of the recording medium 1.

In this case, the distance of the magnetic field generating section 24 from the surface of the recording medium 1 is 20 to 3011 m, which is the thickness of the magnetic field generating section holding plate 21 (10 to 2011 m) compared to the case of FIG. 3 (approximately 10 μm).
However, unlike the case shown in FIG. 3, the magnetic field generating section 24 has a ring shape, so that the magnetic field generation efficiency is good and a strong magnetic field can be generated with less electric power.

Therefore, it is possible to use a coil with even lower impedance than in the case of FIG. 3, and as a result, the recording characteristics of the head can be improved more than in the case of FIG.

Furthermore, even if the circular portion 21b and the recording medium 1 come into contact due to surface precision or waviness of the recording medium 1, or disturbances such as dust adhering to the surface of the recording medium 1, the circular portion 21b and, by extension, the magnetic field generating portion 24 can easily Since it moves backward, the surface of the recording medium 1 is not damaged.

As explained in FIG. 2, the information recorded on the recording medium 1 can be reproduced by detecting the reflected laser beam with a detection system (not shown) built into the optical head 20.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a head for a magneto-optical disk in which the recording characteristics are improved by bringing a low impedance coil closer to the recording medium without damaging the recording medium.

Furthermore, since the magnetic field generating section is integrated with the optical head via the magnetic field generating section holding plate, there is no need to place the optical head and the magnetic field generating section on both sides of the substrate as in the past, simplifying and downsizing the device configuration. In addition, in the case of a substrate having recording media formed on both sides, by arranging the head on each of both sides of the substrate, information can be recorded on both sides at the same time.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the present invention in detail. FIG. 2 is a conceptual diagram showing a configuration example of a fixed type magnetic field modulation type head. FIG. 3 is a diagram showing a configuration example of a floating type magnetic field modulation type head. In Figure 0, which is a conceptual diagram, ■ is a recording medium, 2 is a substrate, 2a is a rotating shaft,
5 is a laser light source, 6 is an optical system,
20 is an optical head, 21 is a magnetic field generating part holding plate, 2
1a is a hole, 21b is a circular part, 21c is a bellows, 22 is a soft magnetic ring, 23 is a magnetic coil, 2
4 represents a magnetic field generating part, and 4 represents a magnetic field generating part, respectively.

Claims (1)

[Claims] A magneto-optical disk head using a magnetic field modulation method used in a magneto-optical disk device, which comprises a laser light source (5) and a recording medium located outside of which the laser light emitted from the laser light source (5) is transmitted. (1) An optical head (20) that includes at least an optical system (6) for focusing on a predetermined position; ), and a magnetic field generating unit holder made of a resin film that is fixed to the optical head (20) at the end and holds the magnetic field generating unit (24) near the laser beam focus position so that the laser beam is not blocked. A head for a magneto-optical disk characterized by comprising a plate (21).