JPH0644502A - Driving device for magneto-optical recording medium - Google Patents

Abstract

PURPOSE:To prevent the erroneous recording and erroneous erasing of information by decreasing the friction heat occurring in sliding of a magnetic field generator or obviating the generation of the friction heat. CONSTITUTION:A magnetic field generating surface 52c which is contactless with a magneto-optical recording medium 11 and medium sliding surfaces 52a, 52b consisting of materials having excellent lubricity and wear resistance are formed in a magnetic field generator 51 of the contact type magnetic field generator. This magnetic field generating surface is disposed to face the position irradiated with a laser beam spot and the medium sliding surfaces are disposed outside recording tracks. Mounting of the magnetic field generator on a holding member with casters is possible as another method. The magnetic field generator is mounted to a slider made of a dielectric substance and is floated by utilizing the repulsive force of the static electricity of the same polarity electrified on the surface of the slider and the magneto-optical recording medium in the case of the contactless type magnetic field generator. The magnetic field generator is connected to the focus driving part of an optical head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a magneto-optical recording medium, and more particularly to the structure of a magnetic field generator for applying a bias magnetic field to a magnetic layer provided on the magneto-optical recording medium.

[0002]

2. Description of the Related Art For example, a magneto-optical recording medium such as a magneto-optical disk which has been put to practical use as an external storage device of a computer has at least a magnetic layer (for example, a rare earth element) on a transparent substrate.
A thin film including a transition metal-based amorphous perpendicular magnetization film) is formed, and the magnetic layer is irradiated with a laser beam through a transparent substrate to locally raise the magnetic layer to a temperature near the Curie temperature or higher. Meanwhile, a bias magnetic field is applied to the magnetic layer from the magnetic field generator to reversibly reverse the magnetization direction of the magnetic layer to record and erase information.

The magnetic field generator for applying a bias magnetic field to the magnetic layer includes a contact type that slides on the magneto-optical recording medium when the medium is driven and a non-contact type that is held at a position separated from the magneto-optical recording medium. There is. In the contact-type magnetic field generator, the magnetic field generator can be arranged closer to the magnetic layer, and the distance from the magnetic field generator to the magnetic layer can be kept substantially constant by following the surface wobbling of the medium. Therefore, it is superior to the non-contact type in that stable recording and erasing can be performed with a small magnetic field. On the other hand, the contact-type magnetic field generator has a drawback that the magnetic field generator itself and the magneto-optical recording medium are easily damaged by friction or impact. On the other hand, the advantages and disadvantages of the non-contact type magnetic field generator are opposite to those of the contact type magnetic field generator, and they have the advantage that they are less likely to be adversely affected by friction and the like. It is difficult to stably hold the magnetic field generator at a certain distance, and problems such as damage to the magnetic field generator and the magneto-optical recording medium due to size increase and crash occur.

As a means for solving the drawbacks of the contact type magnetic field generator, there has been conventionally known, for example, Japanese Patent Laid-Open No. 64-42.
As described in Japanese Unexamined Patent Application Publication No. 039, a lubricant film is formed on a thin film, or as described in, for example, JP-A-64-43834 and JP-A-1-227241. A polymer sheet or a non-magnetic metal thin plate is proposed. On the other hand, as a non-contact type magnetic field generating device, a floating type device has been conventionally proposed in which an air flow generated when a magneto-optical recording medium is driven is used to float the magnetic field generating device from the medium surface.

[0005]

In order to make the contact-type magnetic field generator highly practical, it is necessary to improve the wear resistance and impact resistance of the magneto-optical recording medium as in the above-mentioned known art. Insufficiently needs some means for removing the influence of frictional heat generated by sliding between the magneto-optical recording medium and the magnetic field generator. That is, if the temperature of the magnetic layer is raised by frictional heat, it becomes difficult to control the temperature of the magnetic layer by laser beam irradiation, and erroneous recording or erasing of information is likely to occur. On the other hand, the floating magnetic field generator
Since crashes are likely to occur due to changes in weather conditions and external vibrations, in order to make the non-contact magnetic field generator highly practical, it is necessary to develop a means for holding the magnetic field generator more reliably. is there.

The present invention has been made to solve the above problems, and an object thereof is to provide a contact type magnetic field generator having a structure in which frictional heat does not act on a recording track, and to make it compact and excellent in operation stability. Another object of the present invention is to provide a drive device including the non-contact magnetic field generator.

[0007]

In order to solve the above problems, the present invention firstly irradiates a magnetic layer provided on a magneto-optical recording medium with a laser beam spot through the magneto-optical recording medium. In a drive device for a magneto-optical recording medium in which an optical head and a magnetic field generating device for applying a bias magnetic field to the magnetic layer are arranged to face each other, the magnetic field generating device is not in contact with the magneto-optical recording medium. A magnetic field generating surface and a medium sliding surface made of a material having excellent lubricity and wear resistance are formed, and the magnetic field generating surface is arranged opposite to the irradiation position of the laser beam spot, and the medium sliding surface is formed. The surface was arranged outside the recording track.

Secondly, in a drive device having a contact type magnetic field generator similar to the above, the magnetic field generator is mounted on a non-magnetic holding member with casters, and the casters are brought into contact with the magneto-optical recording medium. The magneto-optical recording medium and the magnetic field generating surface of the magnetic field generating device are always driven with a constant space.

Thirdly, in a drive device equipped with a non-contact type magnetic field generator, the magnetic field generator is mounted on a slider made of a dielectric material, and static electricity of the same polarity is placed on the surface of the slider and the magneto-optical recording medium. Are charged, and the repulsive force acting between these sliders and the magneto-optical recording medium is used to
The magnetic field generation device was made to float above the magneto-optical recording medium.

Fourthly, in a drive device for a magneto-optical recording medium in which an optical head and a magnetic field generating device are both disposed on one side of the magneto-optical recording medium, the magnetic field generating device is used as a focus driving section of the optical head. The magneto-optical recording medium and the magnetic field generating surface of the magnetic field generating device are driven so as to always maintain a constant distance according to the focusing operation of the optical head.

[0011]

According to the first means, since the medium sliding surface of the magnetic field generator is made of a material having excellent lubricity and wear resistance, the magnetic field generator can be slid on the magneto-optical recording medium at high speed. Even if it is moved, the generation of frictional heat is low, and the temperature rise of the magneto-optical recording medium is suppressed. Therefore, it becomes easy to control the temperature of the magnetic layer,
Accidental recording or erasure of information is prevented. Further, the wear of the magnetic field generator is reduced, and the durability of the magnetic field generator is improved.

According to the second means, since the carrier rolls and contacts on the magneto-optical recording medium, the heat generation of the magneto-optical recording medium is lower than that in the case where the magnetic field generator is in surface contact with the magneto-optical recording medium. Similar to the above, temperature control of the magnetic layer by laser beam irradiation is facilitated, and erroneous recording and erasing of information can be prevented.

According to the third means, the electrostatic repulsive force acting between the slider and the surface of the magneto-optical recording medium is used to levitate the magnetic field generator from the magneto-optical recording medium. By controlling the height, both members can be made extremely close to each other, and the magnetic field generator can be downsized. Further, since both members are forcibly separated by utilizing the electrostatic repulsive force, a high crash prevention effect can be obtained.

According to the fourth means, the magnetic field generating device is driven in accordance with the focusing operation of the optical head, and the magneto-optical recording medium and the magnetic field generating surface of the magnetic field generating device are always driven with a constant space. Therefore, the gap between the magneto-optical recording medium and the magnetic field generation surface of the magnetic field generation device can be narrowed, and the magnetic field generation device can be miniaturized. Further, since the magnetic field generator is connected to and supported by the focus drive unit,
The magnetic field generator cannot crash.

[0015]

【Example】

<First Embodiment> A first example of a magneto-optical drive device according to the present invention will be described below with reference to FIGS. FIG. 1 is a configuration explanatory view of a magneto-optical disk and a drive device of this example, and FIG. 2 is a sectional view showing a mutual relationship between the magneto-optical disk and a magnetic head. In these figures, 11 is a magneto-optical disk, 21 is a disk drive unit that rotationally drives the magneto-optical disk 11, 31 is an optical head that irradiates the magnetic layer 14 provided on the magneto-optical disk 11 with a laser beam spot, and 51 is A magnetic field generator for applying a bias magnetic field to the magnetic layer 14 is shown.

As shown in more detail in FIG. 2, the magneto-optical disk 11 of the present example is transparent with a guide groove 12a for guiding the laser beam spot on one side and a prepit 12b for displaying the address of the recording area. Substrate 12;
The first enhancement layer 13 carried on the surface of the transparent substrate 12 on which the guide grooves 12a and the prepits 12b are formed, the magnetic layer 14 laminated on the first enhancement layer 13, and the second enhancement layer laminated on the magnetic layer 14. The layer 15, the reflective layer 16 laminated on the second enhancement layer 15, the heat insulating layer 17 laminated on the reflective layer 16, the heat conducting layer 18 laminated on the heat insulating layer 17, and the heat conducting layer 18. It is composed of a lubricating layer 19 laminated on top.

The transparent substrate 12 is made of, for example, a transparent ceramic material such as glass or a hard transparent resin material such as polycarbonate, polymethylmethacrylate, polymethylpentene or epoxy, and has a disk shape of a desired diameter having a center hole 12b at the center. Is formed. The guide groove 12a and the pre-pit 12b are formed in a spiral shape or a concentric shape that is concentric with the center hole 12b. The method for forming the guide groove 12a and the pre-pit 12b is a known matter and has no direct relation to the gist of the present invention, and thus the description thereof is omitted.

The first enhancement layer 13 multiple-reflects the signal reproducing beam between the transparent substrate 12 and the magnetic layer 14,
The reproducing sensitivity is improved by increasing the apparent Kerr rotation angle, and the refractive index of light is larger than that of the transparent substrate 12, for example, SiN having a refractive index of about 2.0 to 2.5. SiO, Nd ₂ O ₃ , ZrO ₂ , CeO ₂ , Z
It is formed of a dielectric such as nS.

As the magnetic layer 14, a magnetic layer for magneto-optical recording having any known composition can be used.
Rare earth elements such as Nb, Tb, Dy, Hf, Gd and P
A perpendicular magnetization film made of an amorphous alloy with a transition metal such as t, Fe, Co, Cr or Ni is suitable. As the rare earth element-transition metal-based perpendicular magnetization film, a Tb-Fe-Co-based alloy formed by a sputtering method is particularly suitable, and those obtained by adding Pt or Nb to this also obtain good results. To be

The second enhancement layer 15 prevents the heat of the magnetic layer 14 from diffusing to the reflection layer 16 and protects the magnetic layer 14 from impact and corrosion, and further, the magnetic layer 14 and the reflection layer 16. The laser beam transmitted through the magnetic layer 14 is multiple-reflected between them to improve the reproducing sensitivity by increasing the apparent Kerr rotation angle, and the same enhancer or dissimilar dielectric substance as the first enhance layer 13 is provided. Formed by.

The reflective layer 16 prevents moisture from permeating the magnetic layer 14 and returns the laser beam transmitted through the magnetic layer 14 to the incident side. For example, Au, Ag, P.
t, metal material such as Al, or composed mainly of these metallic materials, for example _{Al-TiO 2, Al-Ti} , Au
It is formed of an alloy material such as -Sn and a high reflectance material such as a so-called silver mirror.

The heat insulating layer 17 is made of, for example, Al ₂ O ₃ , SiO,
In addition to inorganic substances such as SiO ₂ , MgF ₂ , and water glass, for example, photocurable resin, thermosetting resin, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyphenylene oxide, polysulfone,
Polyimide, polyamide imide, polyester imide,
It can be formed by a coating film or a vapor deposition film of a heat-resistant polymer material such as polybenzimidazole, or the heat conduction layer 1
When 8 is formed of a foil, it may be formed with an adhesive or a pressure-sensitive adhesive that adheres the reflection layer 16 and the heat conduction layer 18. The heat insulating layer material is more preferably a material transparent to the recording / reproducing light.

The heat conducting layer 18 is made of Au, Ag, Pt, A.
l, Cu, Sn, Si, Ce, La, In, Ge, P
b, Bi, Te, Ta, Sc, Y, Ti, Zr, Cd,
Metal materials or non-metal materials such as Zn, Se, Sb, Ga, Mg, B and C, or CeO ₂ , La ₂ O ₃ and Si
O, SiO ₂ , In ₂ O ₃ , Al ₂ O ₃ , GeO, Ge
O ₂ , PbO, SnO, SnO ₂ , Bi ₂ O ₃ , TeO ₂
, Ta ₂ O ₅ , Sc ₂ O ₃ , Y ₂ O ₃ , TiO ₂ , Zr
O ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Cr ₂ O ₃ , WO ₂ , W
O ₃ , CdS, ZnS, CdSe, ZnSe, In ₂ S
₃ , In ₂ Se ₃ , Sb ₂ S ₃ , Sb ₂ Se ₃ , Ga ₂
S ₃ , Ga ₂ Se ₃ , GeS, GeSe, GeSe ₂ ,
SnS, SnS ₂ , SnSe, SnSe ₂ , PbS, P
bSe, Bi ₂ Se ₃ , Bi ₂ S ₃ , MgF ₂ , CeF
₂ , CaF ₂ , TaN, Si ₃ N ₄ , AlN, BN, T
It can be formed by a vapor deposition film of an alloy such as iB ₂ , B ₄ C, or SiC, or an inorganic compound, or can be formed by a foil of a substance selected from the above. Further, the heat conductive layer 18 can be formed of a polymer material in which a powder or granular material of the substance selected from the above is dispersed.

The lubricating layer 19 is formed with a lubricant such as graphite, carbon, hexadecane, butyl stearate, oleic acid, ethyl stearate, stearic acid, octadecylamine, and solid stearic acid. As a means for forming the lubricating layer 19, a method of mixing these lubricants with an epoxy resin, a photocurable resin, a thermosetting silicone compound or the like and applying and coating them, and a solvent solution of the lubricant in the heat conducting layer 18 are used. A method of coating the surface, a method of sticking a polymer sheet impregnated with a lubricant to the surface of the heat conductive layer 18, and a method of polishing the surface of the heat conductive layer 18 to apply a lubricant in the formed fine recesses. The method of impregnation can be adopted.

It is more preferable to use a magneto-optical recording medium in which a wear resistant layer is formed instead of the lubrication layer 19 on the heat conduction layer 18 or the lamination of the heat conduction layer 18 and the lubrication layer 19. . The wear-resistant layer is made of a material that does not easily wear even when the yokes 52a and 52b of the magnetic field generator 51 slide.

In order for the surface of the layer to be rubbed and abrasion resistant, there is a way to make the hardness of the material used for the rubbed layer higher than the hardness of the material to be rubbed. The hardness of a substance is
For example, it can be measured by comparing the hardness of various materials with a hardness tester. Hardness test methods include Brinell hardness, Vickers hardness, Rockwell hardness, Shore hardness, Morse hardness and the like. The hardness of general materials is resin, glass, quartz (SiO ₂ ), crystal (S
iO _2), Topaz _{{Al 2 Si 4 (F,} OH) 2}, orthosilicate, zirconia (ZrO _2), corundum (Al ₂ O _3), silicon nitride (Si ₃ N _4), silicon carbide (S
iC), boron carbide (B ₄ C), boron nitride (BN),
It becomes higher in the order of diamonds.

The outermost layer of the magneto-optical recording medium is the magnetic field generator 5.
As a means for preventing abrasion due to sliding and friction such as 1), a substance having a hardness lower than the hardness of the outermost layer of the magneto-optical recording medium is used for the medium sliding surface of the magnetic field generation device 51.

A lubricating layer containing a lubricant is formed on either or both of the outermost layer of the magneto-optical recording medium and the sliding surface of the magnetic field generator 51.

For the outermost layer of the magneto-optical recording medium and the medium sliding surface of the magnetic field generator 51, a surface texture or material having a small friction coefficient is used. In particular, there is a method of using a material having a small amount of frictional heat generation and high thermal conductivity, and a surface structure.

As the above, quartz (SiO ₂ ), quartz (SiO ₂ ), topaz {Al ₂ Si ₄ (F, OH)
₂ }, orthosilicate, zirconia (ZrO ₂ ), corundum (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), boron carbide (B ₄ C), boron nitride (B
N), diamond, etc., a substance having a high hardness is selected from the sequence of hardnesses of the substances, and is used as the outermost layer of the magneto-optical recording medium, and a substance having a low hardness is selected, and the medium sliding surface of the magnetic field generator 51 is selected. Used for etc.

As another example, quartz (SiO ₂ ), quartz (SiO ₂ ), topaz {Al ₂ S, etc. are provided on either the outermost layer of the magneto-optical recording medium or the medium sliding surface of the magnetic field generator 51.
i ₄ (F, OH) ₂ }, orthosilicate, zirconia (ZrO ₂ ), corundum (Al ₂ O ₃ ), or the like is used, while silicon nitride (Si ₃ N ₄ ) or silicon carbide ( SiC), boron carbide (B ₄ C), boron nitride (B
N), a combination of materials selected from diamond and the like (hereinafter collectively referred to as ceramics) also has an excellent effect.

As for the above, both the outermost layer of the magneto-optical recording medium and the medium sliding surface of the magnetic field generator 51 are made to contain the above abrasion-resistant ceramics, rubbers and resins with graphite and the above lubricants. It can be used.

As another example, for example, a material selected from the order of hardness of the above substances is used for the outermost layer of the magneto-optical recording medium, or the surface of the outermost layer of the magneto-optical recording medium is formed of the above substance. It is preferable to coat and use abrasion-resistant rubber or resin on the medium sliding surface or the like of the other magnetic field generator 51, or a combination of the rubber or resin containing graphite or any of the above lubricants.

As the above, one of the outermost layer of the magneto-optical recording medium and the medium sliding surface of the magnetic field generator 51 is selected from the above-mentioned ceramics and has particularly good thermal conductivity and good wear resistance. Is preferable, and on the other hand, a combination of metal or the above-mentioned ceramic having good thermal conductivity is preferable.

When the film thickness of the outermost layer of the magneto-optical recording medium and the sliding surface of the magnetic field generator 51 of each of the above-mentioned embodiments is about 100 Å to several 1000 Å, the sputtering method or the vacuum deposition method is used. Alternatively, it may be formed by a chemical vapor deposition method or the like, but when the film thickness requires several μm,
It is produced by a method of coating a coating solution in which powder of the above-mentioned ceramic, lubricant, etc. is mixed with a resin solution or an adhesive solution. Generally, industrially, the coating method is advantageous because it is cheaper and suitable for mass production. It is more preferable to use an epoxy resin-based adhesive, a thermosetting adhesive-based adhesive, a light- or ultraviolet-curable adhesive-based adhesive, or the like as the adhesive used in the coating method.

On the other hand, in a magneto-optical recording medium, an extremely fine laser beam is used to read and write fine element signals such as pits and grooves of the order of several μm or less,
The generation of dust, fine powder, and other materials that cause errors must be prevented as much as possible. From the above point of view, when considering the forming method, and combining the above ,, one of the outermost layer of the magneto-optical recording medium, the medium sliding surface of the magnetic field generation device 51, and the like is made of the above-mentioned ceramic, quartz (SiO ₂ ),
Crystal (SiO ₂ ), topaz {Al ₂ Si ₄ (F, OH)
₂ }, orthosilicate, zirconia (ZrO ₂ ), corundum (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), boron carbide (B ₄ C), boron nitride (B
It is most preferable to use a substance selected from N), diamond, etc., and the other is a coating film containing a silicon-based compound containing a liquid lubricant or a ceramic as a main component.

The outermost layer of the magneto-optical recording medium and the medium sliding surface of the magnetic field generator 51 in the embodiment of the present invention are uniformly smooth, or the width and length of the prepits and pregrooves (guide grooves) are Alternatively, it is necessary to form the roughness to about 1/10 or less of the height and the depth (0.6 μm or less).

Next, the structure of the drive device will be described. The disk drive unit 21 includes a spindle motor (not shown) and a rotary spindle 2 that is the main shaft of the spindle motor.
2 and a turntable 23 fixed slightly below the tip of the rotary spindle 22. The tip 22a of the rotary spindle 22 is formed to have a diameter that allows the tip 22a to be inserted into the center hole 12b of the magneto-optical disk 11 slightly densely. Is mounted on the turntable 23, the center of rotation of the magneto-optical disk 11 can be determined.

The optical head 31 has a light projecting optical system 32 and a light receiving optical system 33. The projection optical system 32 includes a semiconductor laser 34 and a collimator lens 36 that collimates a laser beam 35 emitted from the semiconductor laser 34.
, A diffraction grating 90, a beam splitter 37 for changing the optical path of the laser beam 34, and an objective lens 3 for focusing the laser spot 34a on the magnetic layer 14 of the magneto-optical disk 11.
8 and. On the other hand, the light receiving optical system 32 includes the objective lens 38, the beam splitter 37, a half-wave plate 39 that adjusts the polarization angle of the reflected light, a detection lens group 40, and the reflected light with an S polarization component and a P polarization component. Beam splitter 41 for splitting into two, a first photodetector 43 for detecting S-polarized component 42, and a second photodetector 45 for detecting P-polarized component 44.
Consists of.

The magnetic field generator 51 of the present embodiment has a yoke 52 made of a ferromagnetic material, a coil 53 wound around a part of the yoke 52, and a coating layer 54 attached to the outer surface of the yoke 52. Consists of. The yoke 52 has a substantially Y-shaped cross section, and the center yoke 52c around which the coil 53 is wound is formed slightly shorter than the outer yokes 52a and 52b provided with the coating layer 54. .
The coating layer 54 is made of, for example, carbon or copper, a lubricant constituting the lubricating layer 19 formed on the magneto-optical disk 11, and a material having excellent lubricity and wear resistance, such as the high hardness ceramic material. It is formed. Although the coating layer 54 is provided on the entire outer peripheries of the outer yokes 52a and 52b in the figure, it is sufficient if the coating layer 54 is formed at least on the medium facing surface of the outer yokes 52a and 52b.

In the magnetic field generator 51 of the present example, the lower surface of the coating layer 54 is the medium sliding surface, and the center yoke 52 is.
The tip portion of c is the generation portion of the recording magnetic field or the erasing magnetic field H. The step s from the surface of the coating layer 54 to the tip of the center yoke 52c is sufficient if the tip of the center yoke 52c does not contact the magneto-optical disk 11. On the other hand, since the magnetic field applied to the magnetic layer 14 decreases as the step s increases, the size of the step s is preferably about 1 to 50 μm in consideration of these.

As shown in FIG. 1, the magnetism generator 51 is attached to an arm 56 via a gimbal spring 55, and the magneto-optical disk 1 is mounted on the turntable 23.
After mounting No. 1, the arm 56 is driven to contact the lubricating layer 19 of the magneto-optical disk 11 with a constant pressure. At this time, as shown in FIG. 2, the tip of the center yoke 52c is positioned on the information recording position AA where the laser beam spot emitted from the objective lens 38 of the optical head is accessed, and the outer yoke 52a,
52b is brought into contact with the outside of the recording area.

In the drive device of the above embodiment, the center yoke 52c, which is a magnetic field generating portion, is constructed so as not to contact the magneto-optical recording medium 11, and the outer yokes 52a, 52b whose medium sliding surfaces are covered with the coating layer 54 are provided. Since the contact is made outside the recording track, as shown in FIG.
Heat J generated by sliding between the magnetic field generator 51 and the magnetic field generator 51
Does not directly act on the recording track on which information is recorded, reproduced, or erased, and the influence of frictional heat can be mitigated as compared with the case where the magnetic field generator 51 slides on the recording track. Further, a coating layer 54 made of a material having excellent lubricity and wear resistance is provided on the outer surfaces of the outer yokes 52a, 52b, and the outer yokes 52a, 52b are slid on the magneto-optical disk 11 via the coating layer 54. Therefore, the generation of frictional heat can be further reduced as compared with the case of directly sliding the outer yokes 52a and 52b made of a ferromagnetic material. In particular, the heat generated in the coating layer 54 of the outer yokes 52a and 52b can be radiated by heat conduction from the outer yokes 52a and 52b, so that the temperature rise due to frictional heat can be reduced. Therefore,
The temperature of the magnetic layer can be easily controlled by laser beam irradiation, and erroneous recording and erasing of information can be prevented.

In the above embodiment, the magnetic field generator 51 has been described by using a so-called double yoke type electromagnet having outer yokes 52a and 52b on both sides of the center yoke 52c. As shown in FIG. 3, it is also possible to use a so-called one-yoke type electromagnet in which the outer yoke 52a is provided only on one side of the center yoke (magnetic field generating portion) 52c.

In the above embodiment, the case where the electromagnet is used as the magnetic field generator 51 has been described as an example, but the present invention can be applied to the case where another type of magnetic field generator such as a magnetic head or a permanent magnet is used.

Further, in the above-described embodiment, the outer yokes 52a and 52b of the magnetic field generator 51 are brought into contact with the outside of the recording track of the magneto-optical disk 11.
When the contact surface of the magnetic field generator 1 and the sliding surface of the medium of the magnetic field generator 51 are sufficiently high and the generation of frictional heat can be suppressed to a low level, as shown in FIG. The outer yokes 52a and 52b of the generator 51 may be brought into contact with the track on the magneto-optical disk 11 to be recorded.

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIG. FIG. 5 is an explanatory view of a drive device according to the second embodiment, in which reference numeral 61 is a magnetic field generator according to the present embodiment, reference numeral 62 is a holding member for the magnetic field generator 61, and reference numeral 63 is provided for the holding member 62. A caster made of a ball-shaped rotating body, reference numeral 64 denotes a bearing that rotatably supports the caster 63, and the same reference numerals are shown in other parts corresponding to those in FIGS. 1 and 2.

The drive device of the present example has a gimbal spring 55.
A holding member 62 having casters 63 is attached to the tip end portion of the arm 56 via, and the magnetic field generator 61 is mounted on the holding member 62. The magnetic field generator of this embodiment has no directivity in movement, and is characterized in that it can be smoothly moved in any direction of 360 degrees.

The holding member 62 is made of a non-magnetic material, and the caster 63 is formed on the lower surface of the holding member 62 via a bearing 64.
Is rotatably attached. As the caster 63, one that smoothly rolls in at least the track direction of the magneto-optical disk 11 and the direction orthogonal thereto is used. As the caster 63, one made of vulcanized rubber mixed with graphite or the like as a lubricant is particularly suitable.
Ceramic bearings 4 are particularly suitable.

The magnetic field generator 61 includes an outer yoke 52a,
No coating layer 54 is formed on the outer peripheral surface of 52b,
Also, the magnetic field generator 51 is formed in the same manner as the magnetic field generator 51 according to the first embodiment, except that the tip end portion of the center yoke 52c is formed to project outward more than the tip end portions of the outer yokes 52a and 52b. As shown in FIG. 5, the magnetic field generator 61 includes a caster 63 and a lubricant layer 1 for the magneto-optical disk 11.
9 is attached to the non-magnetic holding member 62 so that a minute gap g is formed between the tip portion of the center yoke 52c and the lubricating layer 19.

In the drive device of this example, the casters 63 are brought into contact with the lubricating layer 19 of the magneto-optical disk 11 so as to roll, so that frictional heat is generated more than when the magnetic field generator is slid. The temperature can be reduced, the temperature of the magnetic layer can be easily controlled by laser beam irradiation, and erroneous recording or erasing of information can be prevented. In particular, since the casters 63 are attached to the holding member 62 via the bearings 64, the casters 63 rotate smoothly and the effect of reducing frictional heat is high. Further, since the distance between the tip of the center yoke 52c, which is a magnetic field generating section, and the magnetic layer 14 of the magneto-optical disk 11 can be always kept constant, stable recording and erasing of information can be performed with a small magnetic field. .

Also in the drive device of this example, a one-yoke type electromagnet as shown in FIG. 3 can be used, and instead of the electromagnet, a magnetic head, a permanent magnet, or the like can be used.
Other types of magnetic field generators can also be used.

In this example, the caster 63 is attached to the holding member 62 via the bearing 64, but the caster 63 may be attached directly to the holding member 62 without using the bearing.

<Third Embodiment> A third embodiment of the present invention will be described with reference to FIG. FIG. 6 is an explanatory view of the drive device according to the third embodiment, and the reference numeral 20 indicates the magneto-optical disk 1.
1, a reference numeral 71 is a spring arm, a reference numeral 72 is a slider for floating the magnetic field generator 61, and a reference numeral 73 is an electrostatic source for supplying static electricity to the dielectric layer 20 and the slider 72. The other parts corresponding to those shown in FIG. 1, FIG. 2, and FIG. 5 described above are denoted by the same reference numerals.

The drive device of this example is the magneto-optical disk 1
The dielectric layer 20 is formed on the surface of No. 1 and the slider 72 and the magnetic field generator 61 are attached to the tip of the spring-shaped arm 71, and the dielectric layer 20 and the slider 72 are charged with static electricity of the same polarity by the static electricity source 73. Is charged, and the magnetic field generator 61 is levitated from the magneto-optical disk 11 by the repulsive force.

The dielectric layer 20 formed on the surface of the magneto-optical disk 11 also serves as a protective film for the magnetic layer 14 and the like. For example, an inorganic dielectric such as silicon or aluminum oxide or nitride, or For example, it is formed with an organic dielectric such as an ultraviolet curable resin. Slider 72
Are also formed with these dielectrics. The spring-shaped arm 71 supports the slider 72 and the magnetic field generator 61, and is formed of an elastic body such as phosphor bronze.

The magnetic field generator 61 may be the same as that of the second embodiment. In order to prevent collision with the magneto-optical disk 11, the magnetic field generator 61 is preferably set so as not to project from the lower surface of the slider 72, as shown in FIG.

The drive device of this example is the magneto-optical disk 1
1 and the dielectric layer 20 formed on the surface of the spring 1 and the spring-like arm 7
Since the slider 72 mounted together with the magnetic field generator 61 at the tip of 1 is charged with static electricity of the same polarity and the repulsive force causes the magnetic field generator 61 to float above the magneto-optical disk 11, the magneto-optical disk 11 There is no adverse effect due to frictional heat. Further, since the magnetic field generator 61 is not simply levitated by the air flow generated by the rotational driving of the magneto-optical disk 11, the magnetic field generator 61 is levitated by using the repulsive force of static electricity of the same polarity. There is also an effect that the generator 61 is unlikely to crash.

Also in the drive device of this example, a one-yoke type electromagnet as shown in FIG. 3 can be used, and instead of the electromagnet, a magnetic head, a permanent magnet, or the like can be used.
Other types of magnetic field generators can also be used.

The dielectric layer 20 and the slider 72 are also included.
A conductive material may be used as the material for the dielectric layer 20 and a means for constantly supplying static electricity of a constant output from the static electricity generation source 73, but an electric insulator may be used as the material for the dielectric layer 20 and the slider 72, and the dielectric layer 20 and the slider 72 may be used. Static electricity source 73
It is also possible to load with the same kind of electric charge.

<Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is an explanatory diagram of a drive device according to the fourth embodiment, and reference numeral 80 is a magnetic field generation device 6.
1, a position control optical head 81 is an optical head 80.
Outer cylinder, reference numeral 82 is an inner cylinder in which the objective lens 80a is installed, and is slidably inserted into the outer cylinder 81, and reference numeral 83 is the outer cylinder 8.
1, a reference numeral 84 is a connecting member for connecting and fixing the magnetic field generator 61 to the inner cylinder 82, and a reference numeral 85 is a holding member for stably holding the magnetic field generator 61. The same reference numerals as those shown in FIG. 1, FIG. 2, and FIG.

The drive device of this example is based on the magnetic field generator 61.
Is fixed to the inner cylinder 82 of the position controlling optical head 80,
Position control actuator 83 together with the objective lens 80a
It is characterized by being driven by.

The connecting member 84 is made of a non-magnetic material, and has a through hole 84a into which the inner cylinder 82 can be inserted and a through hole 84b into which the yoke 52 of the magnetic field generator 61 can be inserted. The inner cylinder 82 is inserted and fixed to the inner surface of the through hole 84a, and the yoke 52 is inserted and fixed to the inner surface of the through hole 84b. On the other hand, the holding member 85 is made of a non-magnetic material, and has a through hole 85a into which the outer cylinder 81 can be inserted and a through hole into which the support shaft 52d protruding from the upper surface of the yoke 52 can be slidably inserted. 85b and has been opened. Through hole 85a
The outer cylinder 81 is inserted and fixed to the inner surface of the, and the support shaft 52d is slidably inserted into the inner surface of the through hole 85b.

The magnetic field generator 61 may be the same as that of the second and third embodiments. The magnetic field generator 61 is set so that a minute gap g is formed between the magneto-optical disk 11 and the magneto-optical disk 11 even when the inner cylinder 82 is lowered to the lowest position in order to prevent collision with the magneto-optical disk 11. It is preferable. Magneto-optical disk 1
1 through the center yoke 5 of the magnetic field generator 61.
As shown in FIG. 7, the objective lens 38 of the recording / reproducing optical head 31 is positioned at the portion facing 2c.

The magneto-optical disk 11 applied to the drive apparatus of this example is completely different from the magneto-optical disk applied to the drive apparatus of the first to third embodiments because the magnetic field generator 61 is completely non-contact. In contrast, no lubrication layer or wear resistant layer is required on the outermost side. Therefore, as shown in FIG. 7, the outermost side of the magneto-optical disk 11 is covered with a transparent or light-reflective protective film 19a.
Can be covered with. Incidentally, reference numeral 91 in the drawing indicates a SiO ₂ film provided on the surface of the transparent substrate 12. In addition, the same reference numerals are displayed in the portions corresponding to those in FIG. Of course, the magneto-optical disk 11 of this example can be applied to the drive devices of the first to third examples.

The drive device of this example is the magnetic field generator 61.
Since is fixed to the inner cylinder 82 of the position control optical head 80, the magnetic field generator 61 can be completely prevented from crashing. Further, since the magnetic field generator 61 is driven by the position control actuator 83 together with the objective lens 80a, the distance between the magnetic field generation surface of the magnetic field generator 61 and the magnetic layer 14 of the magneto-optical disk 11 is always kept constant. be able to. Therefore, stable recording and erasing of information can be performed with a small magnetic field.

Also in the drive device of this example, a one-yoke type electromagnet as shown in FIG. 3 can be used, and instead of the electromagnet, a magnetic head, a permanent magnet, or the like can be used.
Other types of magnetic field generators can also be used.

In each of the above embodiments, the magneto-optical disk has been described as an example, but it goes without saying that the invention can be applied to magneto-optical recording media of other shapes such as card-shaped magneto-optical recording media.

In addition, in each of the above-described embodiments, the so-called in-groove type magneto-optical recording medium in which the pre-pits 12b are formed on the guide grooves 12a has been described as an example, but the pre-pits 12b are formed between the adjacent guide grooves. The formed so-called on-land type magneto-optical recording medium can also be used.

Further, since the present invention mainly relates to the structure of the magnetic field generator, the magneto-optical recording medium to be used may have any structure regardless of the above embodiment.

[0071]

As described above, according to the present invention,
For a drive device with a contact-type magnetic field generator,
Since frictional heat caused by sliding between the magneto-optical recording medium and the magnetic field generator is reduced, the influence of frictional heat on recording, reproduction, and erasing of information is mitigated, and temperature control of the magnetic layer by laser beam irradiation is performed. This facilitates prevention of erroneous recording and erasing of information. Further, with respect to the drive device having the non-contact type magnetic field generation device, the magnetic field generation device is reliably held and the crash is prevented.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a drive device according to a first embodiment.

FIG. 2 is an enlarged view of a main part of the drive device according to the first embodiment.

FIG. 3 is a cross-sectional view showing another example of the magnetic field generator.

FIG. 4 is a perspective sectional view showing another arrangement example of the magnetic field generator.

FIG. 5 is an explanatory diagram of a drive device according to a second embodiment.

FIG. 6 is an explanatory diagram of a drive device according to a third embodiment.

FIG. 7 is an explanatory diagram of a drive device according to a fourth embodiment.

[Explanation of symbols]

 11 magneto-optical disk 14 magnetic layer 31 optical head 51, 61 magnetic field generator 52 yoke 53 coil 54 coating layer 63 caster 72 slider 83 focusing actuator 84 connecting member 85 holding member

Claims (6)

[Claims] 1. An optical head for irradiating a magnetic layer provided on a magneto-optical recording medium with a laser beam spot through the magneto-optical recording medium, and a magnetic field generator for applying a bias magnetic field to the magnetic layer are opposed to each other. In a drive device for a magneto-optical recording medium arranged in a direction, a magnetic field generating device is provided with a magnetic field generating surface that is not in contact with the magneto-optical recording medium, and a medium sliding member made of a material excellent in lubricity and wear resistance. And a magnetic field generating surface facing the irradiation position of the laser beam spot, a drive device for a magneto-optical recording medium. 2. The drive device for a magneto-optical recording medium according to claim 1, wherein the step between the medium sliding surface and the magnetic field generating surface of the magnetic field generating device is 50 μm or less. 3. The drive device for a magneto-optical recording medium according to claim 1, wherein the magnetic field generator is an electromagnet, a magnetic head, or a permanent magnet. 4. An optical head for irradiating a magnetic layer provided on the magneto-optical recording medium with a laser beam spot through the magneto-optical recording medium, and a magnetic field generator for applying a bias magnetic field to the magnetic layer are opposed to each other. In a drive device for a magneto-optical recording medium arranged in a direction, the magnetic field generator is mounted on a non-magnetic holding member with casters, the casters are brought into contact with the magneto-optical recording medium, and the magneto-optical recording medium and the magneto-optical recording medium A drive device for a magneto-optical recording medium, characterized in that the magnetic field generation surface of the magnetic field generation device is always driven with a constant gap. 5. An optical head for irradiating a magnetic layer provided on the magneto-optical recording medium with a laser beam spot through the magneto-optical recording medium and a magnetic field generator for applying a bias magnetic field to the magnetic layer are relative to each other. In a drive device for a magneto-optical recording medium arranged in the opposite direction, the magnetic field generating device is mounted on a slider made of a dielectric material, and static electricity of the same polarity is charged on the surface of this slider and the magneto-optical recording medium, and these sliders are charged. A drive device for a magneto-optical recording medium, characterized in that the magnetic field generation device is floated above the magneto-optical recording medium by utilizing a repulsive force acting between the magneto-optical recording medium and the magneto-optical recording medium. 6. An optical head for irradiating a magnetic layer provided on the magneto-optical recording medium with a laser beam spot on one side of the magneto-optical recording medium, and a magnetic field generator for applying a bias magnetic field to the magnetic layer. In a provided magneto-optical recording medium drive device, the magnetic field generation device is connected to a focus drive section of the optical head, and the magneto-optical recording medium and the magnetic field generation surface of the magnetic field generation device are connected in accordance with a focus operation of the optical head. A drive device for a magneto-optical recording medium, characterized in that and are always driven at a constant interval.