JPH0256701A - Bias magnetic field impressing device - Google Patents

Abstract

PURPOSE:To reduce the load of the elevating means of a cartridge and the driving means of a core by providing a core to move in the direction along which said core moves to or retreat from the recording surface of a magneto- optical recording medium and a coil to surround the core and non-movable in the above-mentioned direction. CONSTITUTION:When a cartridge 3 is inserted into the driving device of a disk, it is held at a cartridge elevating part 5 and descended. At this time, a core 2 is also interlocked and descended. When the cartridge 3 arrives at the descending edge, the core 2 is descended further by a driving means along a sliding groove 5a and the tip is approached into an aperture part 3a. At this time, the coil 1, since it is fitted at a coil supporting plate 1a, is fixed as it is and become non-movable. Thus, it is not necessary to elevate the heavy coil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for applying a bias magnetic field to a magneto-optical disk, and more particularly to an apparatus for applying a bias magnetic field to a cartridge-type magneto-optical disk.

[Conventional technology]

Magneto-optical disks were developed as rewritable, large-capacity recording media, and are irradiated with laser light that is focused to a diameter of 1 to 2 microns, and the polarity changes depending on whether information is recorded or erased at the irradiated position. A bias magnetic field is applied.

Magneto-optical disks are generally housed in cartridges to protect the medium and facilitate storage and transportation.

FIG. 2 is a schematic perspective view showing the structure of a conventional bias magnetic field applying device. In the figure, reference numeral 3 denotes a cartridge 3 in the form of a child box, and a disc-shaped magneto-optical disk (hereinafter referred to as disk) 4 is accommodated in the cartridge 3 . The cartridge 3 is raised and lowered by a lifting means provided in the disc drive (not shown) when it is attached to the disc drive, and has an optical head 7 (described later) on its upper and lower surfaces.
Openings 3a and 3b for allowing the core 2 to face are formed. The longitudinal direction of the openings 3a and 3b is the radial direction of the disk 4, and the length thereof is slightly longer than the full width of the recording track formed on the disk 4.

The optical head 7 is movable in the radial direction of the disk 4 by a head driving means (not shown), and the optical head 7 is movable in the radial direction of the disk 4.
The laser beam generated by the laser beam is focused to a diameter of 1 to 2 microns by an objective lens 7b facing the opening 3b, and is irradiated onto the disk 4.

On the other hand, a flat core 2 faces the disk 4 facing the upper opening 3a. One end of each of the four disks of the core 2 has a tapered cross section, and the other end is attached to the core support rod 2a. One end of the core support rod 2a engages with a sliding groove 5a provided in a cartridge elevating section 5, which is moved up and down by an elevating means (not shown) of the cartridge 3, and the core support rod 2a is attached to be movable in the vertical direction. The cartridge lifting section 5 grips the cartridge 3 with a U-shaped gripping section, and raises and lowers the core support rod 2a together with the cartridge 3. When the cartridge 3 reaches the lower end, the core support rod 2a moves the sliding portion 5a further downward by a driving means (not shown), and the core 2 enters the opening 3a and approaches the upper surface of the disk 4.

The above core 2, coil 1, and core support rod 2a constitute a bias magnetic field applying device.

[Problem to be solved by the invention]

Since the conventional bias magnetic field applying device is configured as described above, the coil and core move up and down as a unit, which not only makes the support mechanism large and heavy, but also makes positioning difficult. Ta.

On the other hand, in order to efficiently apply a bias magnetic field to the disk, it is necessary to place the core as close to the disk as possible, but if it is possible to form a magnetic path that passes through the core to the laser focal point of the disk, it is not necessary to place the coils close together. There's no need.

This invention was made based on this knowledge, and it is an object of the present invention to reduce the load on the core driving means by separating the coil and the core, so that only the core moves up and down in close proximity to the disk, and the coil remains stationary. With the goal.

[Means for Solving the Problems] A bias magnetic field applying device according to the present invention moves a core in a direction toward and away from a recording surface of a magneto-optical recording medium, surrounds the core, and moves a coil in a direction toward and away from a recording surface of a magneto-optical recording medium. It is immovable and motionless.

[Effect]

According to this invention, the core moves in the direction toward and away from the recording surface of the magneto-optical recording medium and comes close to the recording surface, but the coil remains stationary in the said direction, so that the core driving means does not move. The load is reduced.

〔Example〕

The present invention will be explained below based on drawings showing embodiments thereof.

FIG. 1 is a schematic perspective view showing the structure of a bias magnetic field applying device according to the present invention. In the figure, reference numeral 3 denotes a flat box-shaped cartridge, and the cartridge 3 houses a disc-shaped magneto-optical disk (hereinafter referred to as a disk) 4.

The cartridge 3 is raised and lowered by a lifting means (not shown) provided in the disc drive when it is attached to and removed from the disc drive, and has an upper and lower surface for facing an optical head 7 and a core 2, which will be described later. Openings 3a and 3b are formed. The longitudinal direction of the openings 3a and 3b corresponds to the radial direction of the disk 4, and the length thereof is slightly longer than the full width of the recording track formed on the disk 4.

The optical head 7 is movable in the radial direction of the disk 4 by a head driving means (not shown), and the objective lens 7 directs the laser beam generated from the laser source 7a toward the opening 3b.
At b, the beam is focused to a diameter of 1 to 2 microns and irradiated onto the disk 4.

On the other hand, the flat core 2 faces the disk 4 facing the upper opening 3a. One end of the core 2 on the disk side has a tapered cross section, and the other end is attached to the core support rod 2a. The core support rod 2a has protrusions 2b, 2b at one end thereof that engage with a sliding groove 5a provided in a cartridge elevating section 5 that is raised and lowered by an unillustrated elevating means of the cartridge 3, and extends along the sliding end 5a. It is movable in the vertical direction by a drive means (not shown).

Further, a coil 1 surrounding the core 2 is attached to a coil support plate 1a attached to the frame of the disk drive device. The coil support plate 1a is a flat plate with both ends bent upward and has an opening in the center for allowing the core 2 to face the disk 4.

The cartridge lifting section 5 grips the cartridge with a U-shaped gripping section, and the core support rod 2 is held together with the cartridge 3.
Raise and lower a.

Next, the operation will be explained.

When the cartridge 3 is inserted into the disk drive device, it is gripped by the cartridge elevating section 5 and lowered. At this time, the core 2 also descends in conjunction. When the cartridge 3 reaches the lower end, the core 2 is further lowered by the driving means along the sliding groove 5a, and its tip enters the opening 3a and approaches near the upper surface of the disk 4. At this time, coil l
Since it is attached to the coil support plate 1a, it remains fixed and immovable.

Thereby, there is no need to raise and lower the heavy coil, so the load on the cartridge lifting means, core driving means, and core support mechanism can be reduced and downsized, and the vertical positioning of the core can be improved.

In this embodiment, the core support rod is attached to the cartridge elevating section so that the core moves up and down together with the cartridge, but the present invention is not limited to this.
The core may be moved up and down independently in conjunction with the cartridge using only the driving means.

[Effect of the invention] As explained above, in this invention, the coil is
Since the core is surrounded and immobile with respect to the lifting direction of the cartridge, the load on the cartridge lifting means and the core driving means is reduced, and there is an effect that they can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the structure of a bias magnetic field applying device according to the present invention, and FIG. 2 is a schematic perspective view of a conventional bias magnetic field applying device. 1... Coil la... Coil support plate 2...
- Core 2a...Core support rod 3...Cartridge 4...Magneto-optical disk Note that in the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Depending on the attachment and detachment of the magneto-optical recording medium to and from the medium drive device,
A bias magnetic field applying device that moves in a direction toward and away from the recording surface of the magneto-optical recording medium and applies a bias magnetic field to the magneto-optical recording medium, comprising: a core that moves in the direction; A bias magnetic field applying device comprising: a coil that is immovable with respect to the direction.