JPS60261052A - Optical head for optomagnetic disc - Google Patents

Abstract

PURPOSE:To miniaturize and simplify an optical head by incorporating an optical system for recording and reproduction and a vertical magnetic field generating means required for recording and erasure and assembling them into an air slider. CONSTITUTION:A cavity 71 serving as an optical path of laser light is provided to the air slider 7 floated by the turning of a recording medium 1 and a coil 72 as a magnetic field generating means for generating a magnetic field vertical to the recording medium 1 is wound around the surrounding. Further, an optical system comprising a semiconductor laser 8 and a photodetector 14 is provided integrally on the slider 7. Since the magnetic field generating means and the optical system for recording and reproduction are provided to the slider 7 in the one-body structure, a strong magnetic field is obtained and the miniaturization and simplicity of the optical head are attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical head for a magneto-optical disk, and relates to an improvement of the optical head.

(al) Field of Industrial Application As is well known, a magneto-optical disk device is a device that records and reproduces information on an optical recording medium and erases recorded information using magneto-optical effects.

This magneto-optical disk device irradiates a laser beam onto a predetermined position on a track of a recording medium, magnetically records information at the predetermined position, captures the laser beam reflected from a predetermined position on the track, and converts it into an electrical signal. an optical head equipped with an optical system for reproducing information; and a magnetic field generating means for recording and erasing information by reversing the magnetic pole of a magnetic field in response to a recording signal and an erasing signal. .

(b) Prior Art FIG. 2 is a schematic diagram illustrating an optical head according to an embodiment of the prior art. That is, as shown in FIG. 2, the optical head includes an optical system 4 that generates a laser beam for irradiating the recording medium 1, and a laser beam generated by the optical system 4 that irradiates a predetermined position on a track of the recording medium 1. The laser beam generated by the optical system 4 passes through the objective lens 31 of the optical pickup 3 provided below one surface of the recording medium 1, and is focused onto the recording medium 1.
A predetermined position on the track is irradiated.

Further, from above the other surface of the recording medium, a magnetic field corresponding to a recording signal and an erasing signal is applied perpendicularly to the trunk surface opposite to the track irradiation position of the laser beam by the electromagnet 2 or the permanent magnet 21.

In this way, by simultaneously irradiating laser light onto symmetrical positions on both sides of the disk and applying a magnetic field corresponding to a recording or erasing signal, the magnetization of the recording layer is locally reversed and information is recorded or reversed. The magnetic pole is erased by returning it to its original state.

FIG. 3 is a schematic configuration diagram for explaining another conventional optical head. As shown in FIG. 3, the optical pickup 6 has an optical path along its central axis, and the optical system 4 passes through the optical path.
A coil 5 is wound around the outer periphery of the laser beam irradiated onto a predetermined position on the track of the recording medium 1.
Recording and erasing magnetic fields are generated by the recording current and erasing current flowing through the coil 5, and information is recorded and erased at a predetermined position on the trunk of the recording medium 1.

(C) Problems to be Solved by the Invention However, in the structure of the optical head shown in FIG. There are structural disadvantages such as the need for positioning and the need to temporarily retreat the electromagnet 2 or permanent magnet 21 when the disk is installed.Also, it requires an electromagnet or permanent magnet large enough to cover the entire data zone and is large in shape. There is a drawback.

Further, there is a problem in that the magnetic field generated by the coil 5 and the magnetic field generated for focus tracking of the optical system interfere with each other, making it difficult to obtain the accuracy of focus tracking of the optical system.

(d) Means for Solving the Problems The present invention proposes an optical head that solves the above-mentioned problems and can be miniaturized and simplified. An optical head for a magneto-optical disk that performs recording and reproduction of information, in which an optical system is mounted on an air slider that flies above the surface of the recording medium by relative movement with the medium, and the air slider has light transmission from the optical system. This is achieved by an optical head for a magneto-optical disk having a structure in which a perpendicular magnetic field generating means for recording and erasing information is provided around the transmission path.

In other words, a cavity is provided in the air slider that floats above the medium surface due to the relative motion caused by the rotation of the recording medium, which serves as an optical path for the irradiated and reflected laser beams, and a magnetic field is generated around the cavity in a direction perpendicular to the recording medium. A magnetic field generating means and an optical system that focuses and irradiates a predetermined surface of the trunk of a recording medium through the optical path with a laser beam are provided on the air slider, and the magnetic field generating means and the optical system are integrated into an optical system. By using a head, there is no need for optical adjustment of the optical system, and a strong recording/reproducing magnetic field can be obtained, allowing highly accurate recording/reproducing.

(f) Example Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 4 is a side sectional view of an air slider according to an embodiment of the present invention, and FIG. 1 is a schematic configuration diagram of an optical head according to an embodiment of the present invention, with the same reference numerals as in FIGS. 2 and 3. indicate the same part.

That is, as shown in the side cross section of FIG. 4, the air slider 7, which floats at a constant distance from the surface of the recording medium due to the relative movement caused by the movement of the recording medium 1, is formed of a soft magnetic material.
A cavity 71 extending from the recording medium 1 side to the opposite side is provided, and a coil 72 is wound around the cavity 71 at least toward the side near the recording medium 1. Due to the current flowing through the coil 71, a magnetic field is strengthened and applied from the magnetic material around the cavity 71 in a direction parallel to the optical axis of the laser beam, that is, perpendicular to the surface of the recording medium. This applied magnetic field needs to be reversed when recording and erasing information, but this can be easily achieved by reversing the direction of the current flowing through the coil 73.

Next, as shown in the schematic configuration diagram of the optical head in FIG.
The optical system 4 includes a semiconductor laser 8 that generates a laser beam that irradiates the recording medium, a beam splinter 9 that works to separate the irradiated laser beam from the reflected laser beam from the recording medium, and a beam splinter 9 that makes sure that the irradiated laser beam is always on the recording medium 1. A rotating mirror 10 corrects the irradiation to a predetermined position on the truck, a λ/4 plate 12 that allows the reflected laser light to pass through the beam splinter 9, and a λ/4 plate 12 that focuses the reflected laser light on a predetermined position on the trunk to focus and reflect the irradiated laser light. The objective lens 13 is composed of an objective lens 13 that captures laser light, and a photodetector 14 that detects the reflected laser light separated by a beam splitter 9 and converts recorded information into an electrical signal. It is fitted into a cavity 71 of the air slider 7, and other optical systems are mounted on the air slider 7, and arranged so that the irradiated laser beam and the reflected laser beam pass through an objective lens 13 provided in the cavity 71. .

In operation, a laser beam generated by a semiconductor laser 8 is incident on an objective lens 13 via a beam splinter 9, a rotating mirror 10, and a λ/4 plate 12. The objective lens 13 focuses the incident laser light and irradiates it onto the trunk surface of the recording medium 1 through the cavity 71 of the air slider 7 . On the other hand, the reflected light (received laser light) from the trunk surface is captured by the objective lens 13 and enters the photodetector 14 via the λ/4 plate 12, rotating mirror 10, and beam splitter 9.
The photodetector 14 converts the signal into an analog electrical signal and reproduces the information.

In this way, the structure of the optical head is such that the optical system and the magnetic field generating means are integrated so that the laser beam and magnetic field pass through the cavity 71 of the air slider 7 and irradiate and apply a predetermined position on the track of the recording medium 1. A strong magnetic field and miniaturization can be obtained.

Furthermore, as is clear from the examples of heads used in magnetic disks, the air slider has stable flying properties.
The fluctuation in flying height is very small, less than 0.1 μm. Therefore, there is no need for a focusing mechanism or a complicated mechanical part of the head pick amplifier used in a normal optical head.

This is replaced by optical path correction using a rotating mirror 10 shown in FIG. 4, thereby simplifying the mechanical part. Further, there is no interference between the focus tracking magnetic field and the coil 72, and highly accurate recording and reproduction can be obtained.

In this embodiment, the air slider is provided with a cavity that serves as an optical path, but it goes without saying that the cavity may be filled with a transparent material.

(gl Effects of the Invention As is clear from the above embodiments, according to the present invention, the optical system for recording and reproducing and the magnetic generation means necessary for recording and erasing are integrated into an air slider. , it is possible to downsize and simplify the optical head for magneto-optical recording.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an optical head according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram for explaining an optical head of a conventional embodiment, and FIG. 3 is another conventional embodiment. FIG. 4 is a sectional side view of an air slider according to an embodiment of the present invention. In the figure, 1 is a recording medium, 2 is an electromagnet, 21 is a permanent magnet, 3.6 is an optical pink amplifier, 4 is an optical system, 5, 72
is a coil, 7 is an air slider, 31, 617 is an objective lens, 71 is a cavity, 8 is a semiconductor laser, 9 is a beam splitter, 10 is a rotating mirror, 12 is a λ/4 plate, 13 is an objective lens, 14 is a light Each detector is shown. Figure 1 14 Figure 4

Claims (1)

[Claims] This is an optical head for a magneto-optical disk that records and reproduces information on a recording medium using light and magnetism. An optical head for a magneto-optical disk, characterized in that an air slider is provided with a light transmission path for the optical system, and a perpendicular magnetic field generating means for recording and erasing information is built around the transmission path. .