JPH0636202A - Magneto-optical recording apparatus - Google Patents

Abstract

PURPOSE:To obtain a magneto-optical recording apparatus wherein field strength which is nearly uniform over the whole recording region of a magneto-optical recording medium can be obtained and the amount of heat generated is small. CONSTITUTION:A track-position detection circuit 4 uses the signal of the seek position of an optical pickup 3 as a substitute for a position irradiated with a laser beam on a magneto-optical recording medium 2, and the signal of the seek position is converted into an electric signal and transmitted to an operation circuit 5. A field-strength storage circuit 6 stores an electric current value corresponding to the position in the vertical direction of the magneto-optical recording medium 2. The operation circuit 5 sends the signal from the track-position detection circuit 4 to the field-strength storage circuit 6, and sends a signal returned from the field-strength storage circuit 6 to a field-generation-means drive circuit 7. The field-generation-means drive circuit 7 makes an electric current value instructed by the operation circuit 5 flow to a field generation means 1. Thereby, the field generation means 1 keeps the field strength of the position irradiated with the laser beam of the magneto-optical recording medium 2 nearly definite.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a magneto-optical recording device, and more particularly to a magneto-optical recording device for applying a magnetic field to a recording medium by an electromagnet.

[0002]

2. Description of the Related Art Regarding a bias magnetic field supplying device in a conventional magneto-optical disk device, for example, the magnetic flux density distribution is set within an allowable range of the disk even if the distance between the tip yoke of the electromagnet and the disk changes. JP-A-2-297704. In this publication, a tip yoke having a length corresponding to the recording area is provided at the tip of a center yoke which is shorter than the length of the recording area of the recording medium, and the tip yoke is provided near both ends in the radial direction of the recording medium. A magnetic field adjustment hole is provided. By providing this hole, an increase in the magnetic flux density in the vicinity of both ends of the tip yoke in the recording length direction is suppressed.

However, although it is possible to suppress the increase in the magnetic flux density in the vicinity of both ends of the tip yoke to some extent,
The magnetic field distribution in the radial direction of the recording medium cannot be made uniform. Therefore, it becomes a cause of degrading the reliability of data. In addition, in the vicinity of both ends of the tip yoke, a current more than the current value required to obtain the minimum magnetic field is passed, which causes an increase in temperature rise in the magneto-optical recording device.

In Japanese Patent Laid-Open No. 1-143001, a magnet as an external magnetic field applying means moves and returns from a vicinity of the outer circumference of the magneto-optical disk to a predetermined position close to and oppose the surface of the magneto-optical disk based on a command. It is what makes me. That is, the present invention relates to the loading mechanism of the magnetic field applying device, and attempts to reduce the power consumption and suppress the heat generation of the magnetic field generating means by bringing the magnetic field applying means and the magneto-optical recording medium as close as possible. However, when such a mechanism is placed in a sealed space as a measure against dust, the heat generated by the magnetic field generating means cannot be released to the outside, which also causes the temperature inside the magneto-optical recording device to rise.

[0005]

The present invention has been made in view of the above circumstances, and provides a magneto-optical recording apparatus that obtains a substantially uniform magnetic field strength over the entire recording area of a magneto-optical recording medium and has a small amount of heat generation. Further, the present invention has been made for the purpose of providing a magneto-optical recording apparatus in which the heat generated by the magnetic field generating means is radiated to the outside of the magneto-optical recording apparatus and the temperature rise inside the magneto-optical recording apparatus is suppressed.

[0006]

In order to achieve the above object, the present invention provides (1)
In a magneto-optical recording apparatus having a magnetic field generating means for applying a magnetic field to a magneto-optical recording medium having a magnetic film, and an optical pickup for irradiating the magneto-optical recording medium with a light beam, a detection circuit for detecting the position of the optical pickup. A control circuit for controlling a value of a current flowing through the magnetic field generating means so that a magnetic field intensity of a portion of the magneto-optical recording medium irradiated with a laser becomes constant by a signal from the detection circuit. Further, (2) a sensor for measuring the distance between the recording surface of the magneto-optical recording medium and the magnetic field generating means is provided, and a current corresponding to each address of the magneto-optical recording medium is provided by a signal from the sensor. A variable circuit for changing the value is provided to keep the magnetic field strength of the recording area of the magneto-optical recording medium constant, or (3) the magneto-optical recording medium and the magneto-optical recording medium A chassis that houses an access mechanism and a loading mechanism for recording / reproducing data,
An optical system having a moving mechanism in which a chassis cover for closing the chassis seals the inside and magnetic field generating means for applying a magnetic field to the magneto-optical recording medium moves to a predetermined position in accordance with the loading of the magneto-optical recording medium. In the magnetic recording device, the moving mechanism positions the magnetic field generating means when the magneto-optical recording medium is loaded by fitting a part of an outer yoke of the magnetic field generating means and the chassis cover, (4) In (3) above, a plate with holes having a different coefficient of thermal expansion from the chassis cover is fixed to the chassis cover with holes with one side free, and the chassis is used when the temperature inside the device is low. It is characterized in that the holes of the cover and the holes of the plate do not coincide with each other, but they coincide with each other when the height is high. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining an embodiment of a magneto-optical recording apparatus according to the present invention, in which 1 is a magnetic field generating means, 2 is a magneto-optical recording medium, 3 is an optical pickup, and 4 is an optical pickup. A track position detecting circuit, 5 is an arithmetic circuit, 6 is a magnetic field strength recording circuit, and 7 is a magnetic field generating means driving circuit. The track position detection circuit 4 uses the seek position signal of the optical pickup 3 as a substitute for the position of the magneto-optical recording medium 2 on which the laser beam hits, converts the seek position signal into an electric signal, and transmits it to the arithmetic circuit 5. The magnetic field strength storage circuit 6 stores a current value (for obtaining a specific magnetic field) corresponding to the radial position of the magneto-optical recording medium 2. The arithmetic circuit 5 sends the signal from the track position detection circuit 4 to the magnetic field strength storage circuit 6, and sends the signal returned from the magnetic field strength storage circuit 6 to the magnetic field generation means drive circuit 7. The magnetic field generating means driving circuit 7
Is the magnetic field generation means 1 that outputs the current value instructed by the arithmetic circuit 5.
Shed to. With the above configuration, the magnetic field generating means 1 can keep the magnetic field strength of the magneto-optical recording medium 2 at the position where the laser beam hits substantially constant.

FIG. 2 is a diagram showing another embodiment of the magneto-optical recording apparatus according to the present invention, in which 8 is a cartridge, 9 is a cartridge holder, 10 is a sensor (differential transformer), and 1 is a cartridge.
Reference numeral 1 is a chassis, and other parts having the same functions as those in FIG. 1 are denoted by the same reference numerals. The relationship between the position of the tip yoke and the current value for obtaining the optimum magnetic field is generally determined by the distance (gap) between the magnetic field generating means 1 and the magneto-optical recording medium 2.
It changes as shown in FIG. However, the embodiment shown in FIG. 1 cannot cope with the change in the magnetic field distribution due to the change in the gap. The difference from the embodiment of FIG. 1 is that the differential transformer 10 is attached to the chassis 11 in order to detect the position of the magnetic field generating means 1, and that the magnetic field strength storage circuit 6 operates in the radial direction of the medium and the focus direction. The two points are that the current value for a dimensional position is stored. With such a structure, the tolerance in the thickness direction of the cartridge is ± 0.3.
Since the influence of mm can be eliminated, the variation width of the magnetic field strength becomes smaller than that of the first aspect.

FIGS. 4 and 5A and 5B are views showing another embodiment of the magneto-optical recording apparatus according to the present invention.
FIG. 5A is an exploded view, FIG. 5A is a magnetic head during unloading, and FIG. 5B is a magnetic head during loading.
In the figure, 21 is a holder, 22 is a magnetic head, 22a is a pin, 23 is an arm, 23a is an arm tip, 24 is a low friction resin, 25 is a pin, 26 is a leaf spring, 27 and 28 are chassis covers, 29. Is a spring.

On the upper surface of the holder 21, a magnetic head 22 for applying a magnetic field to the moving range of the optical pickup is rotatably supported by an arm 23 by pins 22a (two places). The arm 23 has a resin 24 with low abrasion resistance on both sides.
Is fixed, and the projection of the resin 24 is fitted into the hole of the support portion on the upper surface of the holder 21 through the hole provided in the arm 23. As a result, the arm 23 and the resin 24 can be integrally rotated with respect to the holder 21. Arm 2
3 is biased in the F direction by the arm tip portion 23a.
The pin 22a is biased in the G direction by the leaf spring 26. At the time of loading, the state in which the arm 23 lifts the magnetic head 22 is released by the contact of the arm tip portion 23a with the pin 25 provided on the chassis (not shown), and the force of the leaf spring 26 brings the magnetic head 22 closer to the optical disk. Move in the direction you want to. Then, a part of the magnetic head 22 is fitted into the chassis cover 27, and the loading of the pin 22a is completed.

FIGS. 6 (a) to 6 (c) are views showing still another embodiment of the magneto-optical recording apparatus according to the present invention, in which 30 is a plate and the other parts which have the same function as FIG. Are given the same reference numerals. On the lower surface of the chassis cover 28, a plate 3 made of a material having a thermal expansion coefficient different from that of the chassis cover 28 is used.
No. 0 has one side fixed so that it does not move, and the other side is fixed with slots and screws so that it can move in the A direction. For example, the chassis cover 28 is preferably made of iron and the plate 30 is preferably made of brass. Since holes are formed in the chassis cover 28 and the plate 30 and the positions of the holes are deviated at a low temperature as shown in FIG. 6B, the chassis covers 27, 28 and the plate 30 are outside the device. Is never put inside. However, when the temperature inside the device rises, the plate 30 expands, and as shown in FIG. 6C, the chassis cover 28 and part of the holes of the plate 30 coincide with each other to let out the air inside. Then, when the temperature inside the device decreases, the state returns to the state shown in FIG. 6B,
Shut off air from the outside.

[0012]

As is apparent from the above description, the present invention has the following effects. (1) In the magneto-optical recording apparatus according to the first aspect, the current for driving the magnetism generating means is changed according to the address of the magneto-optical recording medium, so that the magnetic field of the magneto-optical recording medium hit by the laser beam is always constant. Therefore, highly reliable recording / reproducing can be performed, and unnecessary power consumption is not wasted. (2) In the magneto-optical recording apparatus according to claim 2, the correspondence between the address of the magneto-optical recording medium and the drive current value of the magnetic field generating means is changed depending on the distance between the recording surface of the magneto-optical recording medium and the magnetic field generating means. Therefore, the effect of claim 1 becomes stronger. (3) In the magneto-optical recording apparatus according to claim 3, the magnetic field generating means is positioned when the magneto-optical recording medium is loaded by fitting a part of the outer yoke of the magnetic field generating means and the chassis cover. The heat generated by the means can be radiated to the outside through the chassis cover, and the temperature rise in the magneto-optical recording device can be suppressed. Moreover, since the positioning of the magnetic field generating means is not performed via the cartridge holder, the positioning accuracy of the magnetic field generating means is improved, and highly reliable recording / reproducing can be performed. (4) In the magneto-optical recording apparatus according to claim 4, since the air in the apparatus is discharged to the outside only when the temperature inside the apparatus abnormally rises, the temperature inside the apparatus can be raised with almost no influence of dust. Can be suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a magneto-optical recording device according to the present invention.

FIG. 2 is a diagram showing another embodiment of the magneto-optical recording device according to the present invention.

FIG. 3 is a diagram showing the relationship between the radial position of the magneto-optical recording medium and the magnetic field strength for explaining the embodiment in FIG.

FIG. 4 is a diagram showing still another embodiment of the magneto-optical recording apparatus according to the present invention.

5 is a diagram showing a magnetic head at the time of unloading and at the time of loading in FIG.

FIG. 6 is a diagram showing still another embodiment of the magneto-optical recording apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic field generating means, 2 ... Magneto-optical recording medium, 3 ... Optical pickup, 4 ... Track position detection circuit, 5 ... Arithmetic circuit, 6
... magnetic field strength recording circuit, 7 ... magnetic field generating means driving circuit.

Claims (4)

[Claims] 1. A magneto-optical recording apparatus comprising: a magnetic field generating means for applying a magnetic field to a magneto-optical recording medium having a magnetic film; and an optical pickup for irradiating the magneto-optical recording medium with a light beam. A detection circuit for detection and a signal from the detection circuit control the value of current flowing through the magnetic field generating means so that the magnetic field strength of the portion of the magneto-optical recording medium irradiated with the laser from the optical pickup becomes constant. A magneto-optical recording device comprising a control circuit. 2. A sensor for measuring a distance between the recording surface of the magneto-optical recording medium and the magnetic field generating means is provided, and a current value corresponding to each address of the magneto-optical recording medium is changed by a signal from the sensor. 2. The magneto-optical recording apparatus according to claim 1, further comprising a variable circuit, which keeps the magnetic field strength of the recording area of the magneto-optical recording medium constant. 3. A chassis for accommodating a magneto-optical recording medium, an access mechanism and a loading mechanism for recording / reproducing data on / from the magneto-optical recording medium, and a chassis cover for closing the chassis to hermetically seal the inside, In a magneto-optical recording device having a moving mechanism for moving a magnetic field to the magneto-optical recording medium to a predetermined position according to the loading of the magneto-optical recording medium, the moving mechanism includes the magnetic field generating means. A magneto-optical recording apparatus characterized in that the magnetic field generating means is positioned at the time of loading a magneto-optical recording medium by fitting a part of the outer yoke and the chassis cover. 4. A plate with holes different in thermal expansion coefficient from the chassis cover is fixed to the holed chassis cover with one side free, and when the temperature inside the device is low, 4. The magneto-optical recording apparatus according to claim 3, wherein the holes of the plate are not aligned with each other, and are aligned with each other when they are high.