JPH01287849A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To reduce the weight of a moving part and to attain the high speed access by driving an optical head and an electromagnet by another driving part respectively. CONSTITUTION:The title device provides a cartridge 1 composed of a disk 2 to fit a hub 4 composed of a magnetic body at the central part and a case 3 to house the disk 2 and a rotation driving part 9 to drive the disk 2 coupled at the hub 4. An optical head 12 opposite to one surface of the disk 2 and a head driving body 15 to reciprocate and drive the optical head 12 in the radial direction of the disk 2 are provided and an electromagnet 14 opposite to other surface of the disk 2 and an electromagnet driving body 16 to make the electromagnet 14 opposite to the optical head and synchronize and drive it are provided. Consequently, since the optical head 12 and the electromagnet 14 are driven by respective another driving parts, it is unnecessary to couple mechanically both. Thus, the weight of the moving part can be reduced and the high speed access can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magneto-optical disk device that uses a magneto-optical disk in which a perpendicularly magnetized medium is irradiated with a linearly polarized beam and the polarization of the reflected light is tilted in the opposite direction depending on the direction of magnetization. It is something.

2. Description of the Related Art A cartridge 1 used in this type of magneto-optical disk device is constructed by housing a disc-shaped disk 2 in a case 3, as shown in FIG.

The disk 2 includes a perpendicularly magnetized medium having a property that the polarization of the reflected light is reversed depending on the direction of magnetization when irradiated with a linearly polarized beam, and a hub 4 made of a magnetic material is provided at the center thereof. The case 3 also includes a center hole 5 located at the center of the hub 4 and an opening 6 opening radially from the center hole 5.
and the opening 6 are closed by a shutter (not shown).

Further, an annular protrusion 7 that protrudes inward is formed at the edge of the center hole 5. These protrusions 7 are for preventing the recording section of the disk 2 from coming into contact with the inner surface of the case 3, and the portions that the protrusions 7 come into contact with are located outside the effective area for data writing. be.

Next, the cartridge 1 having such a structure is set in an apparatus by magnetically coupling the hub 4 to a turntable 9 that constitutes a rotational drive unit connected to a motor 8, as shown in FIG. At the bottom of the cartridge 1,
A linear motor 10 is provided, and an optical head 12 having an objective lens 11 is fixed to this linear motor 10. Further, a U-shaped connecting portion 13 is fixed to the optical head 12, and an electromagnet 14 facing the optical head 12 with the cartridge 1 interposed therebetween is fixed to the tip of the connecting portion 13. .

The principle of the magneto-optical disk is based on the Kerr effect, which is a magneto-optical effect. The Kerr effect is a phenomenon in which when linearly polarized light is incident on a perpendicularly magnetized medium, the plane of polarization of the reflected light is shifted in a direction opposite to the polarization direction of the incident light due to the direction of magnetization of the perpendicularly magnetized medium. be. In magneto-optical disk drives, the direction of magnetization of a perpendicularly magnetized medium is set constant in advance, and during recording, an external magnetic field in the opposite direction is applied to the perpendicularly magnetized medium using an electromagnet, and a light beam of about 10 mW is applied to one side of the perpendicularly magnetized medium. The direction of magnetization of the irradiated area is reversed by irradiating the irradiated area to raise its temperature and lowering the coercive force of the irradiated area to below the external magnetic field.Conversely, when erasing, an external magnetic field is applied in the opposite direction to that during recording. The direction of magnetization of the medium is made constant by irradiating it with a light beam. During reproduction, the polarization direction detection means of the optical head detects the magnetization direction of the perpendicularly magnetized medium, converts it into an electric signal, and reproduces the signal.

In order to put this principle into practical use, the optical head 12 and the electromagnet 14 are connected and integrated by the connecting part 13 as shown in FIG. Problems to be Solved by the Invention The first problem is that the optical head 12 and the electromagnet 14 are moved back and forth in the -
Since it is magnetized, the weight of the movable part moved by the linear motor 10 is large, making it difficult to access it at high speed. In particular, in order to prevent the cartridge 1 from coming into contact with the optical head 12 or the electromagnet 14 when the cartridge 1 is attached or removed, it is necessary to make the gap between the optical head 12 and the electromagnet 14 sufficiently large. 14 also has to be increased, which increases the overall size and weight, which becomes an obstacle to achieving high-speed access.

The second problem is that, as mentioned above, since the electromagnet 14 must be made larger, the driving current for the electromagnet 14 to provide the external magnetic field necessary for recording and erasing becomes large, resulting in large power consumption. .

The third problem is that a large amount of force is required to pull up the cartridge 1.

Means for Solving the Problems A cartridge consisting of a disk having a hub made of a magnetic material attached to the center and a case for storing the disk is provided, and a rotation drive unit coupled to the hub to drive the disk is provided. an optical head facing one surface of the disk; a spatula driver for reciprocating the optical head in the radial direction of the disk; an electromagnet facing the other surface of the disk; and an electromagnet facing the optical head. An electromagnetic drive body is provided which is synchronously driven.

Further, the electromagnet is driven in synchronization with the optical head within the optical head moving range, and is driven to extend to the upper part of the hub.

Since the working optical head and the electromagnet are driven by separate drive parts, there is no need to mechanically connect them.
This reduces the weight of the moving parts, enabling high-speed access, and by increasing the movable range of the electromagnet placed above the cartridge, the distance between the optical head and the electromagnet can be narrowed. Moreover, by extending the electromagnet above the hub, the electromagnetic coupling force between the hub and the turntable can be electromagnetically weakened. can be easily attached and detached.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 and 2. The same parts as those described in FIG. 4 and FIG. 5 are designated by the same reference numerals, and explanations thereof will be omitted. In this example,
A linear motor 15 is provided as a dedicated head driver for driving the optical head 12, and a linear motor 16 separate from the linear motor 15 is provided as an electromagnet driver for driving the electromagnet 14. A position sensor 17 is provided along the movement trajectory of the electromagnet 14.

Next, to explain the internal circuit, C:PU18 has RO
M19 is connected and electromagnet setting position register 2
0, a moving track number setting register 21, and an address latch register 22 are each connected to the CPU 18.

The address latch register 22 is connected to an address reproduction circuit 23 to which a reproduction signal is input.

Further, the electromagnet setting position register 20 includes a D/A
:I inverter 24 is connected, and this D/A converter 2
4 and the position sensor 17 are connected to an electromagnetic linear motor control circuit 25, and the linear motor 16 is connected to the electromagnetic linear motor control circuit 25.

Next, an optical head linear motor control circuit 26 to which a tracking error signal is input is connected to the movement track number setting register 21, and the linear motor 15 is connected to this optical head linear motor control circuit 26. .

In such a configuration, the address information of the disk 2 is obtained as a reproduction signal, and is latched by the address reproduction circuit 23 into the address latch register 22 as digital information. The CPU 18 has an address latch register 22.
, the address currently being followed by the light beam is detected, and an appropriate value is output to the electromagnet position setting register 20 so that the electromagnet 14 follows the certain position of the light beam. This value is converted into an analog value by the D/A converter 24 and input to the electromagnetic linear motor control circuit 25. This electromagnetic linear motor control circuit 25 is as follows.

Current electromagnet 1 from set voltage and position sensor 17
The radial position of the electromagnet 14 is controlled so that the positions of the electromagnets 4 and 4 coincide with each other.

On the other hand, the optical head 12 uses the tracking error signal to
The linear motor 15 appropriately brakes the light beam so that it follows the target track. The CPU 18 uses the data bus to set the number of tracks to which the light beam should move in the moving track number setting register 21, and the optical head linear motor control circuit 26 uses the tracking error signal to move the set moving amount correctly and achieve the target. Follow on the track. The CPU 18 sets an appropriate value in the electromagnet setting register 20 and controls the electromagnet 14 to be on the light beam. A program for performing such operations is stored in the ROM 19 in advance.

Next, a second embodiment of the present invention will be described based on FIG. In this embodiment, the movable range of the linear motor 16 that drives the electromagnet 14 and the position sensor 17 are expanded so that the electromagnet 14 can be moved until the electromagnet 14 is above the hub 4.

The hub 4 of the disc 2 and the turntable 9 are attracted by an electromagnetic force of 6N to IOH, and when the cartridge is attached or removed, the case 3 is lifted up with strong force, and the protrusion 7 of the case 3 hits the disc 2. , the disk 2 is lifted up and the hub 4 and turntable 9 are separated. At this time, if only the lifting force applied to the cartridge 1 is applied, the pulling mechanism becomes large, the disk 2 is easily damaged, and the case 3 is also easily damaged, but the electromagnet 14
is located above the hub 4 and applies electromagnetic force in a direction that electromagnetically eliminates the attraction force between the hub 4 and the turntable 9, thereby making it easy to attach and detach the cartridge 1.

Effects of the Invention As described above, the present invention provides a cartridge consisting of a disk having a hub made of a magnetic material attached to the center and a case for storing the disk, and a cartridge coupled to the hub to drive the disk. A drive unit is provided, an optical head facing one surface of the disk, a head drive body for reciprocating the optical head in the radial direction of the disk, an electromagnet facing the other surface of the disk, and a head driver that drives the optical head reciprocatingly in the radial direction of the disk, and an electromagnet facing the other surface of the disk, Since the electromagnet driving body is provided to face the optical head and drive synchronously, the optical head and the electromagnet can be driven by separate driving parts.Therefore, there is no need to mechanically connect the two. The weight of the optical head can be reduced, enabling high-speed access.Also, by increasing the movable range of the electromagnet placed above the cartridge, the cartridge can be easily accessed even if the distance between the optical head and the electromagnet is narrowed. By extending the electromagnet above the hub, the electromagnetic coupling force between the hub and the turntable can be electromagnetically weakened, making it easier to attach and detach the cartridge. It has the following effects:

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal cross-sectional side view showing the first embodiment of the present invention;
The figure is a block diagram, FIG. 3 is a longitudinal side view showing a second embodiment of the present invention, FIG. 4 is a longitudinal side view showing the structure of a cartridge, and FIG. 5 is a longitudinal side view showing a conventional example. . DESCRIPTION OF SYMBOLS 1... Cartridge, 2... Disk, 3... Case, 4... Hub, 9... Rotation drive part, 12...
Optical head, 14...Electromagnet, 15...Head drive body, 16...Electromagnet drive body Applicant: Tokyo Electric Co., Ltd. 1" Figure 3.3.

Claims (1)

[Scope of Claims] 1. A cartridge consisting of a disk having a hub made of a magnetic material attached to the center thereof and a case for storing the disk, and a rotary drive unit coupled to the hub to drive the disk; an optical head that faces one surface of the disk; a head driver that reciprocates the optical head in a radial direction of the disk; an electromagnet that faces the other surface of the disk; and an electromagnet that faces the optical head. A magneto-optical disk device characterized by comprising a synchronously driven electromagnetic drive body. 2. A cartridge consisting of a disk to which a hub made of magnetic material is attached to the center, a case for storing the disk, a rotary drive unit coupled to the hub to drive the disk, and a cartridge facing one surface of the disk. an optical head for reciprocating the optical head in the radial direction of the disk, an electromagnet facing the other surface of the disk, and driving the electromagnet in synchronization with the optical head within the movement range of the optical head. 1. A magneto-optical disk device comprising: a magneto-optical disk drive, and an electromagnetic drive body extending and driving to an upper part of the hub.