JP2505837Y2 - Information recording device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus for recording information by applying a magnetic field to a magneto-optical disk as an information recording medium and irradiating a light beam such as a laser beam.

[0002]

2. Description of the Related Art Conventionally, an optical disc is used as a recording medium in an optical recording and / or reproducing apparatus using a light beam such as a laser beam. There are two types of optical discs, one is a read-only type for each function, a write-once type that allows the user to record only once, and a rewritable type that allows repeated recording and erasing.

One of the methods for realizing rewriting is a thermomagnetic recording method in which a magneto-optical disk is used to perform recording and erasing with a laser beam and a magnetic field (for example, "Applied Physics", No. 57).
Vol. 8 (1988) pp. 1151 to 1161).

This is because the laser beam is used as a heat source to irradiate the magnetic film of the optical disk with the laser beam to locally raise the temperature, and when the temperature exceeds the Curie point, the coercive force of the magnetic film decreases. This is because when a magnetic field is applied by an external magnetic field applying means such as an electromagnetic coil, the magnetic film is magnetized along the magnetic field.

Here, the magneto-optical disk and the magnetic field applying means must be brought as close as possible to each other and a constant distance must be maintained so that a constant magnetic field is applied to the magnetic film. In order to keep the distance between the magneto-optical disk and the magnetic field applying means constant, a permanent magnet as magnetic field generating means,
There is one using a magnetic detection element as a detection means, and a schematic configuration diagram thereof is shown in FIG.

Reference numeral 1 is a magneto-optical disk as a recording medium. Reference numeral 10 denotes an optical head as a light beam irradiating means, which has an objective lens 2 on the magnetic film of the magneto-optical disk 1 (light beam irradiating point 3) for focusing a laser beam oscillated from a laser source (not shown). Prepare The objective lens 2 is held by a holder 9, and a voice coil 4 for moving the objective lens 2 in the focus direction (vertical direction) is wound around the holder 9.

A magnetic head 5 is provided on the base 8 as an external magnetic field applying means for applying a magnetic field for recording information to the magnetic film of the magneto-optical disk 1.

Reference numeral 6 is a permanent magnet for generating a magnetic field for measuring the distance between the magneto-optical disk 1 and the magnetic head 5, and 7 is a Hall element as a magnetic detecting element for detecting the strength of the magnetic field generated by the permanent magnet 6. . The permanent magnet 6 is provided on the holder 9 of the objective lens 2, the Hall element 7 is provided on the base 8 on which the magnetic head 5 is provided, and at positions where the permanent magnet 6 and the Hall element 7 are symmetrical with each other through the magneto-optical disk 1. Has been.

In the information recording apparatus configured as described above, keeping the distance between the magnetic head 5 and the magneto-optical disk 1 constant means that the distance between the objective lens 2 and the magneto-optical disk 1 is
This is performed by using the fact that the focus is controlled by the focus control of the optical head 10. That is, since the distance between the objective lens 2 and the magneto-optical disk 1 is kept constant, the magnetic head 5
By keeping the distance between the objective lens 2 and the objective lens 2 constant, the distance between the magnetic head 5 and the magneto-optical disk 1 is also kept constant.

Here, in controlling the distance between the magnetic head 5 and the objective lens 2, the magnetic field intensity of the magnetic field generated by the permanent magnet 6 is detected by the Hall element 7, and the detected magnetic field intensity is kept constant. It is performed by moving the base 8 provided with the up and down direction.

[0011]

However, the magnetic field generated by the permanent magnet 6 generates a magnetic field in the direction intersecting the disk surface with respect to the magneto-optical disk 1 at the light beam irradiation point 3 on the magneto-optical disk 1. . That is, the magnetic field applied to the magneto-optical disk 1 by the magnetic head 5 for recording information has a bias corresponding to the magnetic field generated by the permanent magnet 6 at the light beam irradiation point 3. Therefore, the magnetic field applied to the magneto-optical disk 1 by the magnetic head 5 does not have an appropriate intensity, and there is a problem that accurate information recording cannot be performed.

The present invention has been made in view of such a point, and provides an information recording apparatus capable of recording good and reliable information.

[0013]

The present invention is directed to a light beam irradiating means for irradiating a recording medium with a light beam for recording information, a magnetic field applying means for applying a magnetic field to the recording medium for recording information, and A magnetic field generating means for detecting a distance between the beam irradiating means and the magnetic field applying means and a detecting means for detecting a magnetic field generated by the magnetic field generating means are provided, and the magnetic field strength detected by the detecting means is kept constant. Thus, the information recording apparatus is such that the magnetic field applying means is controlled to move, and is provided with at least two magnetic field generating elements that generate mutually opposite magnetic fields in the magnetic field generating means.

[0014]

The magnetic field generated by the magnetic field generating element at the light beam irradiation point of the recording medium is canceled by the at least two magnetic field generating elements which generate magnetic fields in opposite directions.

[0015]

[Example] An example of the information recording apparatus of the present invention,
Description will be given with reference to FIGS. 1 and 2.

FIG. 1 is a schematic block diagram of an embodiment of the information recording apparatus of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, reference numeral 11 is a permanent magnet that generates a magnetic field in the opposite direction to the magnetic field generated by the permanent magnet 6. At the light beam irradiation point 3 of the magneto-optical disk 1, the permanent magnet 11 is symmetrical to the permanent magnet 6 centered on the objective lens 2 so as to cancel the magnetic field generated by the permanent magnet 6 for distance measurement. It is provided on the holder 9 of the objective lens 2.

Reference numeral 12 is a Hall element as a magnetic detection element. The Hall element 12 is provided on the base 8 of the magnetic head at a position symmetrical to the permanent magnet 11 via the magneto-optical disk 1 and detects the strength of the distance measuring magnetic field generated by the permanent magnet 11.

The case of writing information on the magneto-optical disk 1 in such a device will be described.

Writing information to the magneto-optical disk 1
The laser light oscillated by the laser source is focused on the light beam irradiation point 3 on the magneto-optical disk 1 by the objective lens 2 of the optical head 10, the temperature of the light beam irradiation point 3 rises, and the magnetic film has a Curie point temperature or higher. When the magnetic field holding force decreases, the magnetic head 5 applies a magnetic field according to the recorded information.

At the time of writing information on the magneto-optical disk 1, the distance between the objective lens 2 and the magneto-optical disk 1 and between the magnetic head 5 and the magneto-optical disk 1 is controlled to be constant. That is, in order to accurately focus the above-mentioned laser light on the light beam irradiation point 3 on the magneto-optical disk 1,
This is also because the magnetic head 5 should be as close as possible to the magneto-optical disk 1 without contacting the magneto-optical disk 1 and a constant distance should be maintained so that the magnetic head 5 can always apply a constant magnetic field to the magnetic film.

The distance between the objective lens 2 and the magneto-optical disk 1 is controlled so that the laser light emitted from the laser source is focused on the light beam irradiation point 3 by the objective lens 2 of the optical head 10. At this time, the movement of the objective lens 2 for the distance control is performed by the voice coil 4 provided in the optical head 10.
By.

Further, the distance between the magnetic head 5 and the magneto-optical disk 1 is controlled by utilizing this focus control.
That is, since the distance between the objective lens 2 and the magneto-optical disk 1 is kept constant by the focus control, the magnetic head 5
By keeping the distance between the objective lens 2 and the objective lens 2 constant, the distance between the magnetic head 5 and the magneto-optical disk 1 is also kept constant. In controlling the distance between the magnetic head 5 and the objective lens 2, the Hall elements 7 and 12 detect the strengths of the magnetic fields generated by the permanent magnets 6 and 11 for distance measurement, and the strengths are constantly detected. As described above, the base 8 of the magnetic head 5 is moved in the vertical direction. That is, the Hall elements 7 and 12 are moved and controlled so that the magnetic fields of the permanent magnets 6 and 11 are constantly detected.
2 and a magnetic head 5 on the same base 8 and a permanent magnet 6
The distance between the objective lens 2 and 11 and the objective lens 2 on the same holder is kept constant. In the distance measurement provided with two sets of the permanent magnet and the hall element, it is possible to measure the distance at two different points, as compared with the distance measurement with one set of the permanent magnet 6 and the hall element 7 shown in FIG. 2 which is a conventional example. It is possible to improve the accuracy of distance control with respect to the fluctuation of the magneto-optical disk 1. Similarly, by further providing a permanent magnet and a Hall element, the distance control accuracy can be further improved.

Now, in this embodiment, the permanent magnet 6 and the objective lens 2 are centered with respect to the magnetic field generated by the permanent magnet 6 in the direction intersecting the disk surface of the magneto-optical disk 1 at the light beam irradiation point 3. Since the permanent magnet 11 that generates a magnetic field in the opposite direction to the permanent magnet 6 is provided at the symmetrical position, the magnetic field component of the light beam irradiation point 3 in the disk surface intersecting direction is canceled, and the influence of the permanent magnet for distance measurement is eliminated. To be done. Thus, the magnetic field applied to the magneto-optical disk 1 by the magnetic head 5 for recording information is not affected by the permanent magnets 6 and 11 for measuring the distance, and good and accurate information recording is possible. Is done.

[0025]

[Effect of the Invention] As is apparent from the above description, the present invention is
A permanent magnet that generates a magnetic field in a direction opposite to the magnetic field generated by the permanent magnet for distance measurement is provided, and the magnetic field for distance measurement at the light beam irradiation point is canceled. Therefore, the influence of the distance measuring magnet on the magnetic field applied by the magnetic field applying means for information recording can be eliminated, and good and reliable information recording can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an information recording apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of an embodiment of a conventional information recording device.

[Explanation of symbols]

 1 Magneto-optical disk (recording medium) 2 Objective lens 3 Light beam irradiation point 4 Voice coil 5 Magnetic head 6 Permanent magnet 7 Magnetic detection element (Hall element) 8 Base 9 Holder 10 Optical head 11 Permanent magnet 12 Magnetic detection element (Hall element) )

Claims (1)

(57) [Scope of utility model registration request] 1. A light beam irradiation means for irradiating a recording medium with a light beam for recording information, a magnetic field applying means for applying a magnetic field to the recording medium for recording information, a light beam irradiation means and a magnetic field applying means. A magnetic field generating means for detecting the distance of the magnetic field and a detecting means for detecting the magnetic field generated by the magnetic field generating means, and the magnetic field applying means is moved so that the magnetic field strength detected by the detecting means is kept constant. In the controlled information recording apparatus, the magnetic field generating means comprises at least two magnetic field generating elements which generate magnetic fields in mutually opposite directions.