JPH0194556A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To restrain the calorific value of a coil and to attain a high-speed access by driving an optical head and a bias magnetic field generating coil built-up body by separate driving sources and controlling the bias magnetic field generating coil build-up body based on the detection signals of the two position detecting sensors of a controls circuit. CONSTITUTION:The title device is provided with a driving mechanism to follow- up-drive a bias magnetic field generating coil built-up body 3 in the radius direction of a magneto-optical disk by a driving source 6 separate from that of an optical head 2. The title device is equipped with a position detecting sensor 9 to detect the radius-directional position of the optical head 2 to the magneto-optical disk 1 and a position detecting sensor 10 to detect the radius- directional position of the bias magnetic field generating coil built-up body 3 to the magneto-optical disk 1. The driving mechanism is controlled so as to follow-up-move the bias magnetic field generating coil built-up body 3 toward the radius-directional moving position of the optical head 2 based on the detection signals of the two position detecting sensors 9 and 10. Thus, the calorific value based on a current supplied to the coil of the bias magnetic field generating built-up body becomes smaller and the high-speed access can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Misiri Nazuto-sen (industrial application field) The present invention irradiates a light spot onto a magneto-optical disk through an optical head driven in the radial direction of the magneto-optical disk, and also applies a bias magnetic field. The present invention relates to an improvement in a magneto-optical disk device that applies a bias magnetic field using a generating coil assembly and writes recorded information to an irradiated location on the magneto-optical disk.

(Prior Art) Conventionally, for example, as shown in FIG. 5, a light spot P is irradiated onto the magneto-optical disk 1 via an optical head 2 driven in the radial direction of the magneto-optical disk 1, and a bias magnetic field is generated. A magneto-optical disk device is known in which a bias magnetic field is applied by a coil assembly 3 to write recording information at a location irradiated with a light spot. In this magneto-optical disk device, in order to move the bias magnetic field generating coil assembly 3 in the radial direction toward the radial movement position of the optical head 2 with respect to the magneto-optical disk 1, the bias magnetic field generating coil assembly 3 is moved to the arm 4. connected to the optical head 2 via
The optical head 2 and the bias magnetic field generating coil assembly 3 are configured to be driven by the same drive source. Furthermore, as shown in FIG. 6, the magneto-optical disk device is provided with a bias magnetic field that covers the entire irradiation area of the light spot irradiation location from the inner circumference side to the outer circumference side in the radial direction of the magneto-optical disk 1. Using the generator coil assembly 3.

There is also a device in which the bias magnetic field generating coil assembly 3 is of a fixed configuration and a bias magnetic field is applied to the location where the light spot is irradiated to write recorded information on the magneto-optical disk 1. Note that 5 indicates a spindle motor.

(Problems to be Solved by the Invention) However, in the conventional method, the bias magnetic field generating coil assembly 3 is connected to the optical head 2 and the bias magnetic field generating coil assembly 3 is moved to follow the position of the optical head 2 in the radial direction. In the magneto-optical disk device, the weight of the optical head 2 is the arm 4, the bias magnetic field generating coil 3 is the weight of the optical head 2, and the bias magnetic field generating coil 3 is
There is a problem in that the weight becomes larger due to the weight carried on the disk, and the weight balance deteriorates, which is not preferable from the viewpoint of high-speed access.

In addition, the bias magnetic field generating coil assembly 3 is used, which covers the entire irradiation area from the inner circumferential side to the outer circumferential side in the radial direction of the magneto-optical disk 1.
In a magneto-optical disk device that has a fixed configuration and applies a bias magnetic field to the spot irradiated with a light spot and writes recorded information to the magneto-optical disk 1, the area to which the bias magnetic field is applied is large, so it is difficult to obtain the desired magnetic flux density. The number of turns of the coil must be increased compared to that of a magneto-optical disk device configured to move the bias magnetic field generating coil assembly 3, and the current flowing through the coil must be increased. Since the resistance also increases, there is a problem in that the amount of heat generated increases.

The present invention has been made in view of the above circumstances.

The purpose of this is to suppress the amount of heat generated due to the current flowing through the coil of the bias magnetic field generating coil assembly to a small value, and to create a structure in which the bias magnetic field generating coil assembly is moved to follow the radial movement position of the optical head. It is an object of the present invention to provide a magneto-optical disk device capable of high-speed access even when

(Means for Solving the Problems) A feature of the magneto-optical disk device according to the present invention is that the magneto-optical disk device according to the present invention is driven by a drive source different from the drive source for the optical head that is driven in the radial direction of the magneto-optical disk. A drive mechanism that drives the bias magnetic field generating coil assembly to follow the radial direction of the magneto-optical disk, a position detection sensor that detects the radial position of the optical head relative to the magneto-optical disk, and a radius of the bias magnetic field generating coil assembly relative to the magneto-optical disk. and a position detection sensor for detecting the directional position, and a drive mechanism thereof so as to follow and move the bias magnetic field generating coil assembly toward the radial movement position of the optical head based on the detection signal of the position detection sensor. This is where a control circuit is provided.

(Function) According to the present invention, the optical head and the bias magnetic field generating coil assembly are driven by separate drive sources, and the bias magnetic field generating coil assembly is driven based on the detection signal of the part position detection sensor of the control circuit. The optical head is moved to follow the position of the optical head in the radial direction.

(Embodiment) An embodiment of the magneto-optical disk device according to the present invention will be described below with reference to the drawings.

1 and 2 show a first embodiment of a magneto-optical disk device according to the present invention, and FIG. 1 shows a drive mechanism for a bias magnetic field generating coil assembly of the magneto-optical disk device according to the present invention. , FIG. 2 shows a control circuit for a drive mechanism of a bias magnetic field generating coil assembly of a magneto-optical disk device according to the present invention. 1 and 2, the same as the conventional example.
The same reference numerals are given to the constituent elements.

In FIG. 1, reference numeral 6 denotes a rotary drive source that constitutes a part of the drive mechanism of the bias magnetic field generating coil assembly 3. For example, a stepping motor is used as the rotational drive source 6. One end of an arm 8 is attached to the output shaft 7 of the rotational drive source 6 .

A bias magnetic field generating coil assembly 3 is attached to the other end of the arm 8. The bias magnetic field generating coil assembly 3 has a known structure consisting of a yoke, a core, and a coil wound around the core.

The rotation drive source 6 is controlled by a control circuit shown in FIG. 2 so that the bias magnetic field generating coil assembly 3 follows the position of the optical head 2 relative to the magneto-optical disk 1 in the radial direction. The circuit is optical head 2
A position detection sensor 9 detects the radial position of the bias magnetic field generating coil assembly 3 with respect to the magneto-optical disk 1.

In this embodiment, the position detection sensor 9 includes a light source section 11 that emits a parallel light beam, a diffusion lens 12 that diffuses the parallel light beam, and a light receiver 13 that receives the light beam that has passed through the diffusion lens 12. There is. The diffusion lens 12 includes
Here, a cylindrical lens is used that diffuses parallel light beams in a uniaxial direction, and the diffusion lens 12 is provided on the optical head 2. Note that the light source section 11 and the light receiver 1
3 and is fixedly arranged in a housing (not shown) opposite to each other through the diffusion lens 12. In this embodiment, the optical head 2
is provided with a diffusion lens 12, but the diffusion lens 12
It is also possible to have a configuration in which the optical head 2 is fixed to the housing and the light receiver 13 is provided in the optical head 2.

According to this position detection sensor 9, as shown in FIG.
The diffusion angle of the parallel light beam in the uniaxial direction by the diffusion lens 12 is θ (unit: radian), and the total amount of light beam emitted through the diffusion lens 12 is P. From the diffusion focus f to the light receiver 1.
3 is the distance to R1.If the amount of light received by the light receiver 13 is P, then the relationship p2cxp□/Rθ holds, the photoelectric conversion coefficient of the light receiver 13 is G, and the current value of the detection signal output from the light receiver 13 is calculated. Then, the relationship Iαa p 1/Rθ holds, and since the photoelectric conversion coefficient G, total light amount P, and diffusion angle θ are constant, the distance R from the diffusion focal point f to the receiver 13 can be found by the current value. The position of the optical head 2 can be detected using this current value.

The detection signal of the photoreceiver 13 is amplified by an amplifier 14. The detection signal amplified by the amplifier 14 is used as a radial reference position signal of the optical head 2 with respect to the magneto-optical disk 1, and is input to the subtracter 15. The detection signal of the position detection sensor 10 is input to the subtracter 15 together with the radial reference position signal. Here, a potentiometer is used as the position detection sensor 10,
The position detection sensor 10 is attached to the rotating shaft 7.

The subtracter 15 outputs a differential output toward the amplifier 16 based on the detection signal of the position detection sensor 10 and the radial reference position signal, and the differential output amplified by the amplifier 16 is input to the rotational drive source 6. The rotational drive source 6 is controlled so that the bias magnetic field generating coil assembly 3 moves following the movement of the optical head 2 in the radial direction.

In the drive mechanism of this embodiment, the movement of the optical head 2 in the radial direction relative to the magneto-optical disk 1 draws a linear trajectory, while the movement of the bias magnetic field generating coil assembly 3 in the radial direction relative to the magneto-optical disk 1 is caused by the arm 8. Since it is driven to rotate, it will draw a circular arc trajectory. Note that the area to which the bias magnetic field of the bias magnetic field generating coil assembly 3 is applied is determined based on the characteristics of the control circuit.
It is desirable to design such that the light spot irradiation point P' can be covered by taking into consideration errors such as a following error based on a difference between a circular trajectory and a straight trajectory.

FIG. 4 shows a second embodiment of the magneto-optical disk device according to the present invention. A bias magnetic field generating coil assembly 3 is provided at the lower part of the belt 17, and the belt 17 is driven back and forth so that the radial movement of the bias magnetic field generating coil 3 with respect to the magneto-optical disk 1 becomes a linear trajectory. In addition to configuring the position detection sensor 10, the position detection sensor 9
Similarly, the light source section 11', the diffusion lens 12', and the light receiver 13
', and the diffusing lens 12' is provided above the belt 17.

As described above, in the embodiment, the position detection sensor 9 is connected to the light source section 1.
The optical head 2 is provided with a rack, and the housing is provided with a pinion that meshes with the rack and a potentiometer that rotates integrally with the pinion to adjust the potentiometer. It is also possible to employ a conventional position detection sensor that detects the radial position of the optical head 2 with respect to the magneto-optical disk 1 based on a change in the resistance value of a meter.

As explained above, the magneto-optical disk device according to the present invention has a drive mechanism that drives the bias magnetic field generating coil assembly to follow the radial direction of the magneto-optical disk by a drive source different from the optical head. and a position detection sensor that detects the radial position of the optical head with respect to the magneto-optical disk and a position detection sensor that detects the radial position of the bias magnetic field generating coil assembly with respect to the magneto-optical disk. Since a control circuit is provided to control the drive mechanism so that the bias magnetic field generating coil assembly is moved to follow the position of the optical head in the radial direction based on the detection signal of the sensor, the coil of the bias magnetic field generating coil assembly is In addition to being able to suppress the amount of heat generated due to the current flowing through the optical head, high-speed access is possible even when the bias magnetic field generating coil assembly is configured to move in accordance with the movement of the optical head. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a drive mechanism of a bias magnetic field generating coil assembly of a magneto-optical disk device according to the present invention, FIG. 2 is a diagram showing a control circuit of the driving mechanism of the bias magnetic field generating coil assembly, and FIG. 1 is for explaining the detection principle of a position detection sensor for detecting the radial position of the optical head with respect to the magneto-optical disk shown in FIG. 1, and FIG. 4 is a second embodiment of the magneto-optical disk device according to the present invention. A diagram showing an example, FIG.
FIG. 6 is a diagram showing an example of a conventional magneto-optical disk device. 1... Magneto-optical disk, 2... Optical head 3
...Bias magnetic field generating coil assembly 6...Rotary drive source, 8...Arm 9.10...Position detection sensor, 17...Belt Fig. 2n Fig. 3 Fig. 4 Fig. 5 Figure 6

Claims (1)

[Claims] (1) A light spot is irradiated onto the magneto-optical disk through an optical head driven in the radial direction of the magneto-optical disk, and a bias magnetic field is applied by a bias magnetic field generating coil assembly to irradiate the light spot on the magneto-optical disk. A magneto-optical disk device for writing recorded information on a location, the drive mechanism driving the bias magnetic field generating coil assembly in a radial direction of the magneto-optical disk by a drive source different from the optical head; A position detection sensor that detects the radial position of the optical head and a position detection sensor that detects the radial position of the bias magnetic field generating coil assembly with respect to the magneto-optical disk, based on detection signals of both position detection sensors. and a control circuit for controlling the drive mechanism so that the bias magnetic field generating coil assembly is moved to follow the radial movement position of the optical head.