JPH0739062Y2 - Magneto-optical disk drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a disk drive device for a magneto-optical disk recorded by a magnetic modulation method.

[Outline of the Invention] The magneto-optical disk drive device according to the present invention is provided with a cantilever that comes into contact with the disk surface and oscillates due to this surface wobbling. The displacement of this cantilever is detected by a non-contact type position sensor, and by this sensor output. The position control drive means of the magnetic field generating coil is driven so that the distance between the disk surface and the magnetic field generating coil is always kept constant.

[Conventional technology]

In a magnetic modulation type magneto-optical disk drive device, a magnetic field generating coil is arranged so as to move corresponding to the optical head in the radial direction of the disk, and this magnetic field generating coil causes an external magnetic field of 100 Oe or more on the disk surface. Is applied to modulate this magnetic field with a recording signal (several hundreds to several MHz).

In the magneto-optical disk drive device configured as described above, it is necessary to prevent the magnetic field generating coil from coming into contact with the disk even if the disk warps and is large. A large distance (0.4 to 0.5 mm) must be placed between the surfaces, and in this case, in order to apply a sufficient external magnetic field on the disk surface, a considerably large current must be applied to the magnetic field generating coil. There is a problem in terms of power consumption, projection and heat generation of the coil.

Therefore, conventionally, as a means for solving these problems, a support member for supporting a magnetic field generating coil has been made movable also in a direction orthogonal to the disk surface, and a trochanter is attached to the support member of this coil. Roll the child onto the disk surface,
A method has been proposed in which the distance between the disk surface and the magnetic field generating coil is kept constant by moving the support member mechanically following the warp of the disk surface.

Also, the magnetic field generating coil is made movable in a direction orthogonal to the disk surface by an actuator, and this actuator is driven and controlled by the detection light reflected on the disk surface by using an optical sensor to drive the magnetic field generating coil to the disk surface. A method is also considered in which the gap between the disk surface and the disk surface is kept constant by following the warp of the disk.

[Problems to be solved by the device]

The former method of mechanical follow-up by a trochanter, which has been conventionally considered as a disc surface follow-up means of a coil for generating a magnetic field in a magneto-optical disc drive apparatus using a magnetic modulation system, is considerably used for a trochanter that is brought into contact with a disc surface. Due to the mass, vibration may occur due to the rolling contact of the trochanter on the disk, which may adversely affect the servo system of the optical beam of the optical head
Further, the latter method using the optical sensor cannot be easily realized in a state where a label or the like is printed on the disc surface.

The present invention has been made in view of the above point, and its purpose is to generate a magnetic field without adversely affecting the optical system servo or even if a label is printed on the surface of the disc. (EN) Provided is a magneto-optical disk drive device in which a magnetic coil is controlled so as to follow the surface deflection of a disk so as to always keep a constant distance from the disk surface.

[Means for Solving the Problems]

In order to achieve the above object, the magneto-optical disk drive device according to the present invention comprises a magnetic field generating coil mounted integrally with an optical head so as to move in the radial direction of the disk by an electromagnetic driving means in a direction orthogonal to the disk surface. In addition to being controllable, the electromagnetic drive means is driven by the output of a non-contact type position sensor that detects the displacement of the cantilever biased so as to come into contact with the disk surface. It is configured to keep the interval constant.

[Action]

With this configuration, the cantilever whose tip contacts the disk surface is displaced following the surface wobbling of the disk, and this displacement is detected by the non-contact type position sensor, and the electromagnetic drive means is driven by the output of this sensor. Driven,
By this drive, the magnetic field generating coil is controlled to move in the direction orthogonal to the disk surface, and the distance between the disk surface and the magnetic field generating coil is kept constant.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In the figure, (1) is a magneto-optical disk (hereinafter simply referred to as a disk), which is rotated by a predetermined rotation driving means (not shown). Reference numeral (2) is a substantially U-shaped thread that corresponds to the disk (1) in a substantially radial direction, and has an optical actuator (3a on the upper surface of one end, the lower side (2a) in the figure. ) And an objective lens (3b) are mounted, and the optical head (3) faces the lower surface of the tip of the other side, that is, the upper side (2b) in the figure, in the optical axis direction. Then, the magnetic field generating coil (4) is mounted by the coil actuator (5) so as to be movable in the vertical direction.

The magnetic field generating coil (4) is formed by winding the coil (4a) around a bobbin (4b), and the bobbin (4b) is wound around the movable coil (5a) of the coil actuator (5). It is adapted to be inserted into (5b) and tightened and fixed at an arbitrary position by a height adjusting screw (6).

A support portion (2c) is laterally projected from the tip surface of the upper side (2b) of the thread (2), and a cantilever (7) is attached to the lower surface of the support portion (2c) via a leaf spring (8). This cantilever (7) is extended inward so that the tip (7a) contacts the surface of the disc (1) in the vicinity of the magnetic field generating coil (4) as described later. .

The L-shaped arm (9) is horizontally fixed to the movable bobbin (5b) of the coil actuator (5) corresponding to the cantilever (7), and the bent tip (9a) of the arm (9) is fixed. Optical sensor (10) corresponding to the cantilever (7)
Is installed. The optical sensor (10) is composed of a light emitting element (11) such as an LED and a pair of upper and lower light receiving elements (12) and (13) such as a photodiode. The light emitting element (11) and the light receiving elements (12) and (12) 13) are attached to the upper surface of the bent tip portion (9a) of the arm (9) so as to face each other with the above-mentioned cantilever (7) sandwiched in the lateral direction.

The optical sensor (10) is incorporated in the drive circuit of the coil actuator (5) as shown in FIG. That is, the light receiving elements (12) and (13) are connected to the movable coil (5a) wound around the movable bobbin (5b) of the coil actuator (5) and connected to the input side of the drive circuit (14). A feedback servo circuit is formed by connecting the light receiving elements (12) and (13) via an actuator (5) so that the light amount entering the light receiving elements (12) and (13) becomes equal.

Further, the sled (2) to which the optical head (3), the magnetic field generating coil (4), the cantilever (7), the optical sensor (10), etc. described above are attached to the disk (1) loaded in the rotary drive unit. The guide shaft (16) is inserted through the lower side (2a) in the case shown in the drawing, and the feed screw shaft (17) is parallel to the guide shaft (16).
The belt (21) is passed between the pulley (18) fixed to one end of the feed screw shaft (17) and the pre (20) fixed to the shaft of the motor (19). The feed screw shaft (17) is rotated by the rotation of the motor (19), and the sled (2) is moved in the inner peripheral direction or the outer peripheral direction with respect to the disc (1).

Next, the operation of the magneto-optical disk drive device of this example configured as described above will be described.

First, by supplying an electric current to the coil actuator (5), the magnetic field generating coil (4) is moved in the axial direction and is opposed to the surface of the disk (1) at a predetermined interval, that is, a reference interval. The reference interval of the magnetic field generating coil (4) is arbitrary by loosening the height adjusting screw (6) and adjusting the bobbin (4b) in and out of the movable bobbin (5b) of the coil actuator (5). Can be set to.

Then, in this state, the disk (1) is rotated by the rotation driving means, and the thread (2) is transferred by the drive of the motor (19) to move the optical head (3) and the magnetic field generating coil (4) to the disk ( The optical head (3) irradiates the back surface of the disk (1), that is, the recording surface with a light beam (laser light) by moving it in the radial direction with respect to 1), and the front surface side facing the irradiation portion of the light beam. Recording is performed by generating a magnetic field by the magnetic field generating coil (4).

When the disc (1) is warped in this recording operation, surface wobbling occurs due to rotation, but the tip (7a) follows the surface wobbling and the tip (7a) is near the magnetic field generating coil (4). The cantilever (7) in contact with the surface of the device swings up and down to correspond to the light receiving element (12) or (13), and the light receiving element (12) and (13) are connected to the light emitting element (1).
The amount of light entering from 1) is changed, so that the coil actuator (5) is driven so that the amount of light entering the light receiving elements (12) and (13) becomes equal, and the feedback loop is closed.

In this state, the movable bobbin (5b) of the coil actuator (5) moves up and down following the vertical swing of the cantilever (7) according to the surface wobbling of the disk (1), and the magnetic field is applied from the surface of the disk (1). The distance to the generating coil (4) is kept constant, that is, the magnetic field generating coil (4) is held in a state of being opposed to the surface of the disc (1) at a reference interval. A predetermined magnetic field can be generated for (1).

Also, since the mass of the cantilever (7) is very small, the above-mentioned swing does not adversely affect the servo system of the optical head (3), and the label is printed on the surface of the disc (1). Even if it exists, the position of the magnetic field generating coil (4) can be controlled by driving the coil actuator (5) without being affected by this.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, as a moving means of the sled (2), a linear drive system can be used without using a motor and a feed screw shaft, and each member such as the sled (2) can be formed in various shapes without being limited to the illustrated shape. It is a thing.

[Effect of device]

As described above, according to the present invention, the distance of the magnetic field generating coil from the disk surface does not adversely affect the optical system servo, and even when a non-reflective layer such as label printing is formed on the disk surface. It is possible to control recording so as to keep it constant without being affected by any effect, and it is possible to perform recording reliably even on a disk in which surface wobbling occurs.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a magneto-optical disk drive device according to the present invention, FIG. 2 is an enlarged perspective view of an essential part of the same, and FIG. 3 is a drive circuit diagram of a magnetic field generating coil. In the figure, (1) is a magneto-optical disk, (3) is an optical head,
(4) is a magnetic field generating coil, (5) is a coil actuator, (7) is a cantilever, and (10) is an optical sensor.

Claims (1)

[Scope of utility model registration request] 1. A magnetic field generating coil mounted so as to move integrally with an optical head in the radial direction of a disk is controllable by an electromagnetic drive means in a direction orthogonal to the disk surface, and the electromagnetic drive means is provided. The distance between the disk surface and the magnetic field generating coil is kept constant by being driven by the output of a non-contact type position sensor that detects the displacement of a cantilever urged to come into contact with the disk surface. A magneto-optical disk drive device.