JPS62112253A - Light magnetic head - Google Patents

Abstract

PURPOSE:To obtain the light magnetic head which can write the new information immediately after the information is erased by generating respectively the bias magnetic field in the different direction mutually in two focusing lenses arranged in the direction along the recording track on the recording media and two focused light spot positions. CONSTITUTION:The third beam 3 is focused on the recording track on recording media 5 through the first focusing lens 4, and the first fine light spot 6 is formed. The part irradiated on the recording track is magnetized in the constant direction specified by the first bias magnetic field 71 and the information is erased. The second beam 8 to come out from an optical system 2 is focused on the recording track through the second focusing lens 9 adjacent and provided to the side where the recording media 5 are shifted and the second fine light spot 10 is formed. The light spot 10 is in the second bias magnetic field 111 generated by the second bias magnetic field generating means 11, by modulating the second beam 8, the magnetized inverting pattern in accordance with the pulse-shaped signal is formed at the part erased by the first light spot 6 on the recording track, and the new information is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical head that records, erases, and reads information on a recording medium using both optical means and magnetic means.

[Conventional technology]

A laser beam is used as a light source, and this laser beam is modulated with a pulsed signal from an external information source, and the magneto-optic effect is used to record binary information on the surface of the recording medium, or to record information that has already been recorded. In a magneto-optical head that reads data, recording is performed by applying a bias magnetic field in the opposite direction to a recording medium that has been previously magnetized in one direction, and focusing the laser beam into a minute optical spot on the surface of the recording medium using a condensing lens. This is carried out by heating the surface of the recording medium in accordance with the pulsed signal, inverting the magnetization of this portion, and forming a magnetization reversal pattern in accordance with the pulsed signal.

On the other hand, erasing is performed by applying a bias magnetic field in one direction and irradiating the recording medium with direct current laser light to remagnetize the recording medium in the same direction for the section of the recording track to be erased.

[Problem that the invention seeks to solve]

However, conventional magneto-optical heads have only one condensing lens and only one light spot for writing, reading, and erasing.
To rewrite information that has already been recorded,
For example, in magneto-optical disk drives, after erasing recorded information, the only way to write new information is to wait for the disk to rotate to its original position, making it impossible to rewrite information at high speed. Ta. Furthermore, since it is necessary to switch the direction of the bias magnetic field during recording and erasing, it is necessary to provide a coil and current reversal circuit for generating the bias magnetic field, or to reverse the magnet. Therefore, due to the influence of this change in the magnetic field, the position of the condensing lens shifts, causing problems in focusing the laser beam on the surface of the recording medium and causing problems in recording.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above drawbacks and provide a magneto-optical head that does not require reversal of the bias magnetic field and can write new information immediately after erasing already recorded information.

[Means for solving problems]

The magneto-optical head of the present invention includes two condensing lenses arranged in a direction along a recording track on a recording medium, and two light spots condensed by the two condensing lenses having different directions from each other. and bias magnetic field generating means for respectively generating bias magnetic fields.

[Effect]

The two light spots focused by the two condensing lenses are made to follow the same rank j, j: By performing the erasing operation by direct current irradiation and recording by modulating the laser light with the following light spot, the erasing and recording operations can proceed almost in parallel with only a slight delay. , it becomes possible to rewrite information at high speed. In addition, in the magneto-optical head with this configuration, there is no need to switch the direction of the bias magnetic field, and since the direction of the bias magnetic field is always constant, there is no adverse effect on the position of the condenser lens, and the laser beam can be focused on the recording medium surface. There will be no errors in the data, and stable erasing and recording operations will be possible.

〔Example〕

FIG. 1 is a conceptual diagram showing an embodiment of the present invention.

This magneto-optical head includes an optical system 2 and a first optical system inside a housing 1.
and second condensing lenses 4, 9, first and second bias magnetic field generating means 7, 11, and actuator 41.91
It is equipped with

A first beam 3 emitted from the optical system 2 is focused onto a recording track (not shown) on a recording medium 5 via a first condensing lens 4, and forms a minute first light spot 6. form. The optical spot 6 is located in the first bias magnetic field 71 generated by the first bias magnetic field generating means 7, and the recording medium 5 is irradiated with the first beam 3 in a direct current manner according to a manual signal from an external control device. (the direction is indicated by an arrow 51 in the figure), the part of the recording track irradiated by the first beam 3 is magnetized in a fixed direction determined by the first bias magnetic field 71, and the part that was previously recorded is magnetized in a certain direction determined by the first bias magnetic field 71. Information will be erased.

The second beam 8 emitted from the optical system 2 is at a position along the recording track with respect to the first condensing lens 4.
The light is focused onto the recording track via a second condenser lens 9 installed close to the side on which the recording medium 5 is moving, forming a minute second light spot 10 . The optical spot 10 is generated by the second bias magnetic field 111 (the first bias magnetic field 71) generated by the second bias magnetic field generating means 11.
By modulating the second beam 8 with an external control or pulsed signal, the first light beam on the recording track 2 is moved as the recording medium 5 moves. A magnetization reversal pattern corresponding to the pulsed signal is formed in the portion erased by the spot 6, and new information is recorded.

Note that focus control to always optimally focus the first and second beams 3 and 8 on the recording medium surface and tracking control to cause the focused first and second light spots 6.10 to follow the recording track are performed. , similar to the control in a conventional magneto-optical head with one condenser lens, actuators 41 and 91 provided for the condenser lens 4.9, and position detectors in each direction provided in the optical system 2 ( (not shown) and an external control circuit.

FIG. 2 shows first and second bias magnetic field generating means 7, 1.
1 is a cross-sectional view showing an example of the configuration of No. 1 together with condensing lenses 4 and 9 and a recording medium 5. FIG.

In this configuration, the bias magnetic field generating means 7.11 are cylindrical air-core coils surrounding the condensing lenses 4 and 9, respectively,
The air-core coil generates a magnetic field in the direction of the lens optical axis of the condenser lens 4°9. By appropriately setting the direction of the current flowing through each air-core coil, it is possible to generate mutually opposite magnetic fields at the two light spot positions. Alternatively, a yoke 12 may be provided on the back side of the recording medium 5 to form a magnetic path from the first bias magnetic field generating means 7 to the second bias magnetic field generating means 11 to further strengthen the bias magnetic field. Further, instead of the air-core coil, a cylindrical permanent magnet magnetized in the radial direction or the thickness direction may be used. Alternatively, a configuration may be adopted in which the magnetic path 12 is made of a magnet and no bias magnetic field generating means is provided on the condenser lens side.

〔Effect of the invention〕

With the configuration described above, it is possible to obtain a magneto-optical head that can erase information that has already been recorded using a preceding optical spot and record new information using a following optical spot in parallel. .

According to this magneto-optical head, it is possible to rewrite information at high speed. In addition, since it is not necessary to switch the direction of the bias magnetic field, the position of the condenser lens can be stably controlled.
Stable erasing and recording operations are possible.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the magneto-optical head according to the present invention, and FIG. 2 is a sectional view showing an example of the configuration of the first and second bias magnetic field generating means in FIG. 1...Magneto-optical head housing 2...Optical system 3...First beam 4...First condensing lens 5... ... Recording medium 6 ... First optical spot 7 ... First bias magnetic field generating means 8 ...
...Second beam 9...Second condensing lens 10...Second optical spot 11...Second bias magnetic field generating means 41.9
1... Actuake agent patent attorney Iwa
Yoshiyuki Sa Figure 1 Figure 2

Claims (1)

[Claims] (1) Two condensing lenses arranged in the direction along the recording track on the recording medium, and generating bias magnetic fields in different directions at the positions of the two light spots condensed by the two condensing lenses. 1. A magneto-optical head having bias magnetic field generating means for generating a bias magnetic field.