JPH0495253A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To reduce the total thickness of a magneto-optical disk device by using in common a permanent magnet for focus/tracking control of an objective lens and magnet for generation of the data recording/erasing external bias magnetic filed for the magneto-optical disk in a paired form and furthermore fixing these magnets independently of a carriage. CONSTITUTION:A carriage 9 movable in the radius direction of a magneto- optical disk 10 is provided together with an objective lens holder 2 which contains an objective lens 1, focus coil 4, a tracking coil 3, etc., and the magnets 5 nd 6 which are fixed independently of the carriage 9 so that the same magnetic poles are set counter to each other on a carriage shift path. Then the magnetic fields close to the same magnetic poles are used for the focus and tracking control purposes among those magnetic fields generated by both magnets 5 and 6. Meanwhile the optical axis direction component of the magnetic filed is used as a bias magnetic filed which decides the magnetic filed direction when the data are recorded and erased to the disk 10 at a position near the recording area of the disk 10. As a result, a thin and light-weight magneto-optical disk device is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magneto-optical disk device capable of recording, reproducing and erasing data for computers and the like.

2. Description of the Related Art A magneto-optical disk is a recording medium that can record a large amount of information and can be repeatedly erased and reproduced. Magneto-optical disk drives use laser light to record and reproduce signals on tracks on the disk surface, and require a high-precision servo mechanism to make the laser beam follow the target track on the disk surface. be. Generally, a coil actuator performs servo operation of the objective lens, and a linear motor moves the pickup in the radial direction of the disk to perform inter-track access operation.

In the optical modulation method, which is one of the methods for recording signals on a disk, the laser beam is modulated, the temperature of the laser beam on the recording film is raised to above the Curie point, and the external magnetic field is used to magnetize the area perpendicular to the disk surface. When erasing the signal, the direction of the external magnetic field is reversed and magnetized in the opposite direction.

In general, optical pick amplifiers often include a two-axis actuator that drives an objective lens in both a focus control direction and a tracking control direction. FIG. 4 shows the configuration of the shaft sliding rotary actuator. An objective lens 41, a focus coil 42, a tracking coil 43, and a balancer 46 are attached to the objective lens holder, which is a movable part, and this holder is connected to a support shaft 4 attached to a fixed part.
8 (tracking control direction) and sliding in the axial direction (focus control direction), and the effective drive portion of the focus coil 42 and tracking coil 43 is formed by a magnet 44, an outer yoke 45, and an inner yoke 47. The magnetic circuit is configured to be located in a magnetic circuit.

When a current is passed through the focus coil 42, an electromagnetic force is generated by the field magnet in the focus control direction, and the objective lens moves in the axial direction. Tracking coil 43
When a current is passed through, an electromagnetic force is generated in the horizontal direction by the magnetic field of the field magnet, and the objective lens 41 rotates around the support shaft.

In the magneto-optical method, it is necessary to apply an external bias magnetic field when recording and erasing signals. Generally, a permanent magnet or electromagnet is placed on the opposite side of the disk from the pink amplifier (on the disk surface), but the bias magnetic field must be reversed for recording and erasing. This can be done by rotating a permanent magnet or by reversing the direction of current in an electromagnet.

Problems to be Solved by the Invention Such conventional optical disk devices have the following problems.

0) A chiorage and an external magnetic field magnet are required between the magneto-optical devices, and the structure is complicated, which impedes the ability to make the device thinner. Furthermore, the mechanism for loading and unloading the optical disk into the device becomes complicated.

(2) With the method of having a magnet on the carriage, the weight of the pickup is large! ll: High-speed access between tracks is difficult.

The present invention solves the above problems and aims to provide a thin and lightweight magneto-optical disk device.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a carriage movable in the radial direction of a magneto-optical disk, an objective lens holder on which an objective lens, a focus coil, a tracking coil, etc. are mounted, and the carriage. The magnets are fixed independently from each other along the carriage movement path so that the same magnetic poles oppose each other.

According to the above-described configuration, the present invention uses the magnetic field near the same magnetic pole out of the magnetic field generated by the magnet for focus control and tracking control, and the optical axis of the magnetic field near the recording area of the magneto-optical deign. The directional component is used as a bias magnetic field that determines the direction of the magnetic field when recording and erasing data on the magneto-optical disk.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an optical pickup actuator of a magneto-optical disk drive according to a first embodiment of the present invention. In the figure, 1 is an objective lens, 2 is an objective lens holder, 7, 8
The objective lens holder is attached to the carriage section 9 by an elastic member for supporting the objective lens holder, and is movable in the focus control direction and the tracking control direction. 3 is a tracking coil, 4 is a focus coil, 5 is a field magnet coil, and 6 is a field magnet yoke. The objective lens section is
It can be moved in the radial direction by a linear motor, and the focus/tracking coil moves in the magnetic field generated by the left and right field magnets. By generating symmetrical magnetic fields in the left and right field magnets as shown by broken lines and passing current through the tracking coil and focus coil, the objective lens moves in the tracking control direction and focus control direction, respectively. In addition, the magnetic fields from the left and right field magnets repel each other, and the directions of the magnetic lines of force are divided into vertical and vertical directions at the center of the pickup. The lower magnetic field lines enter the yoke at the bottom of the field magnet.

Some of the upper magnetic lines of force pass through the disk in an upward direction near the laser beam spot on the surface of the disk 1o. Therefore, it is possible to record and erase magneto-optical signals on the beam spot. Since the bias magnetic field must be reversed during recording and erasing, the direction of the current flowing through the electromagnet is reversed, and in synchronization with this, the current flowing through the focus/tracking coil is also reversed.

FIG. 2 shows a second embodiment. A yoke 6' is provided on the disk surface on the opposite side of the pickup across the disk 1o, and a field magnet coil σ is also provided. The magnetic fields from the left and right field magnets repel each other, and the lines of magnetic force are divided into vertical and vertical directions at the center of the pickup. A portion of the upper magnetic field lines passes through the disk while facing upward in the vicinity of the laser beam spot on the surface of the disk 1o, and enters the yoke 6' above the disk. With this, the magnetic field of the field magnet can be efficiently used for recording and erasing signals. The rest is the same as the first embodiment.

FIG. 3 shows a third embodiment. field magnet coil d
′ is wound around the movable range of the objective lens to generate a magnetic field as shown by the broken line.

The tracking coil 3 and the focus coil 4 are provided below the field magnet coil, and the lines of magnetic force intersect horizontally at the point of action. Furthermore, since the magnetic lines of force perpendicularly pass through the disk in the vicinity of the laser beam spot on the surface of the disk 100, magneto-optical signals can be recorded and erased on the beam spot. When current is applied to the focus coil and tracking coil, the focus control direction and
The objective lens moves in the tracking control direction. As shown in the figure, the tracking coil 3 is stacked in areas other than the point of action (the area where the vertical magnetic fields intersect) to prevent the generation of unnecessary electromagnetic force. The rest is the same as the previous embodiment.

In this way, according to the magneto-optical disk device according to the embodiment of the present invention, the focus and tracking control magnets and the magnet for recording and erasing are arranged so that they are shared, so the structure of the device can be made simple and lightweight. can do.

According to these methods, a power source such as a linear motor for moving the carriage in the radial direction during track axes is not required, and track axes can be performed using only the tracking coils.

Effects of the Invention As is clear from the above embodiments, the present invention provides a permanent magnet for focus control and tracking control of an objective lens, and a magnet for generating an external bias magnetic field for recording and erasing data on a magneto-optical disk. and shared by a set of magnets,
Moreover, since the magnet is arranged to be fixed independently of the carriage, it is possible to reduce the weight of the pickup and enable high-speed access operation. Since a smooth bias magnetic field is not required, it is possible to provide a magneto-optical disk device that allows the entire device to be made significantly thinner.

[Brief explanation of the drawing]

FIG. 1A is a plan view showing the configuration of an optical pick-up actuator of a magneto-optical disk device according to a first embodiment of the present invention;
1B is a side view of the same, FIG. 2 is a side view of the second embodiment of the present invention, FIG. 3A is a plan view of the third embodiment of the present invention, and FIG. 3B is a same side view of the second embodiment of the present invention. 4A is a plan view showing the configuration of an optical pickup actuator of a conventional magneto-optical disk device, and FIG. 4B is a side view of the same. 1... Objective lens, 2... Objective lens holder, 3... Tracking coil, 4...
... Focus coil, 5. s', s"...
・Field magnet coil, 6゜6'... Field magnet yoke, 9... Carriage, 1o...
····disk. Name of agent: Patent attorney Shigetaka Awano and 1 other person 2 Figure 3 +Scoil 5 Kai Makakusai Sotofil

Claims (2)

[Claims] (1) A carriage movable in the radial direction of the magneto-optical disk, and a radius of a tracking groove whose focus is controlled to focus on the recording area of the magneto-optical disk within the carriage and as the magneto-optical disk rotates. an objective lens whose tracking is controlled to follow the deflection in the direction; an objective lens holder that holds the objective lens and is movable in the focus control direction and the tracking control direction; and a focus coil that generates an electromagnetic force in the tracking control direction, a tracking coil, and a magnet that is fixed independently of the carriage so that magnetic poles of the same polarity oppose each other along the carriage movement path, and the magnet Among the magnetic fields generated by the magnet, a horizontal component of the magnetic field is applied to the surface of the magneto-optical disk for the focus control and the tracking control, and a vertical component of the magnetic field generated by the magnet is applied to the magneto-optical disk. A magneto-optical disk device arranged to act as a bias magnetic field that determines the direction of the magnetic field when recording and erasing data. (2) The method according to claim 1, wherein the direction of the magnetic field generated by the magnet is reversed between data recording and data erasing, and at the same time, the current flowing through the focus coil and the tracking coil is also reversed. Magneto-optical disk device.