JPH03219448A - Magneto-optical disks and disk cartridges - Google Patents

Abstract

PURPOSE:To stably float a magnetic head by providing a conductive linear composed of nonwoven fabric on the cartridge of a magneto-optical disk in which first protective film, magneto-optical recording film, second protective film, and UV resin including a grinding agent and lubricant are provided sequentially. CONSTITUTION:In this magneto-optical disk, the first protective film 13, the magneto-optical recording film 14, and the second protective film 15 are formed sequentially on the substrate 1, and it is provided with mixed UV resin 3 incorporating the grinding agent and the lubricant. The liner 25 composed of the nonwoven fabric with conductivity is provided on the inner wall of the disk cartridge 24 of the magneto-optical disk almost in parallel with a disk plane at the installation side of the magnetic head 20. In such a manner, it is possible to prevent the mixed UV resin and dust attached on a slider and the magnetic head from being re-attached, which realizes the stable floating of the magnetic head.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an overridable magnetic field modulation type magneto-optical disk and a disk cartridge.

Background of conventional technology Magneto-optical disks have attracted attention as high-density recording media, and some have been commercialized.

A magneto-optical disk is a recording medium that performs recording and reproduction using light such as a semiconductor laser.

Magneto-optical recording film (TbFeCo, DyF
When a rare earth-transition metal amorphous alloy such as eCo is irradiated with laser light to locally heat it, the coercive force of the magneto-optical recording layer in this region decreases. At this time, external magnetization is applied to change the direction of magnetization to write or erase information.

Information reproduction (using magneto-optical effects such as the Kerr effect and Faraday effect).

The magnetic field modulation method fixes the intensity of the laser beam and modulates the direction of the externally applied magnetic field. As means for generating a modulated externally applied magnetic field, there is a floating magnetic head used, for example, in a magnetic disk device (for example, Japanese Patent Laid-Open No. 1983-1999).
229643).

It is possible to modulate the externally applied magnetic field by modulating the current flowing through the coil of the magnetic head.

However, the magnetic field necessary to reverse the magnetization of the magneto-optical recording layer, which is locally heated by the laser beam, is generated only in the vicinity of the magnetic head, so the distance between the magnetic head and the magneto-optical recording layer should be kept as close as possible. I need to get closer.

Floating magnetic head (Dai) A floating magnetic head that uses gas lubrication to achieve low flying height (e.g., several micrometers or less), and requires a contact, start, stop (hereinafter abbreviated as C8S) method to simplify its configuration. .

In order to perform the C8S method on a magneto-optical disk, ζ is required. 1. When the magneto-optical disk is stationary, 2. The disk surface and the magnetic head slider surface should not stick together. 2. The magnetic head should run in contact when starting and stopping the rotation of the magneto-optical disk. Apparatus It is necessary that the magnetic head does not destroy the magneto-optical recording layer of the magneto-optical disk, and 3. It is necessary that dust that would prevent the magnetic head from flying adheres to the slider surface of the magnetic head.

In order to satisfy the above conditions, it is time to start the substrate. The first protective film, the magneto-optical recording layer and the second protective film are sequentially formed. On top of the second protective film, alumina powder and thermoplastic resin are mixed with the thermosetting resin, and A magneto-optical disk has been proposed in which a film is provided with a mixed resin composition impregnated with a lubricant. (For example, Japanese Unexamined Patent Publication No. 61229643) An example of the above-mentioned conventional magneto-optical disk will be described below with reference to the drawings.

FIG. 6 is a cross-sectional view showing the structure of a conventional magneto-optical disk. In FIG. 6, 11 is a glass substrate, 12 is an ultraviolet curable resin film having a pre-group pattern (usually 10 to 100 μm thick), 13 is a first protective film (usually 60 to 150 nm thick) composed of ZnS or SiN,
] 4 is a TbFeCo magneto-optical recording film (usually thickness 20-15
0 nm), 15 is a second protective film made of ZnS or SiN (usually 60 to 50 nm thick), 16 is a mixed resin composition made of alumina, polyvinyl methyl ether resin, and thermosetting epoxy resin. 17 is a fluorocarbon oil, +L, 19 is a slider, 20 is a magnetic head installed at one end of the slider 19, 21 is an objective lens, (22 is a laser beam, 23 is a disk) It is a rotary drive device.

The operation of the conventional magneto-optical disk constructed as described above will be described below with reference to FIG. 6.

When the disk rotation drive device 23 is stationary (when the slider 1
9 is in contact with the crush prevention film 16 of the magneto-optical disk via a fluorocarbon oil 17.

When the disk rotation drive device 23 is driven, the slider 19
slides on fluorocarbon oil 17. The rotation speed of the disk rotation drive device 23 increases and the slider 19
When the relative speed of the crash prevention film 16 reaches approximately 1 m/s or more, the slider 19 and the magnetic head 20 float from the fluorocarbon oil 17.

After the magnetic head 20 floats, the magnetic head 20, objective lens 21, and laser beam 22 are moved to an arbitrary position on the disk by an access drive system (not shown).
The magneto-optical recording film 14 is locally heated by the magnetic head 20.
Information is written in the magneto-optical recording film 14 by passing a modulated current through a head coil (not shown).

When recording and reproducing information on the magneto-optical disk is completed and the disk rotation drive device 23 is stopped, the slider 19 and the magnetic head 20 shift from floating running to sliding running, and run in contact with the fluorocarbon oil 17 as a lubricant. It rests on the anti-crash film 16.

Problems to be Solved by the Invention However, when the +1css test is repeated with the above configuration, dust floating in the atmosphere adheres to the fluorocarbon oil 17 on the anti-crash film 16, and this dust collects on the slider 19 and the magnetic field. The problem is that the particles re-adhere to the head 20, preventing the magnetic head 20 from flying and running, making the strength of the magnetic field applied to the magneto-optical recording film 14 unstable, preventing complete information writing, and increasing reproduced signal errors. In view of the above-mentioned problem, the present invention has the problem that the adsorption L between the crash prevention film 16 and the magnetic head 20 occurs in a high-temperature C8S, albeit unsteadily. This provides a magneto-optical disk in which there is no dust adhesion and the magnetic head 20 is not attracted to the magneto-optical disk, and the magnetic head can fly stably.

Means for Solving the Problems In order to solve the above problems, a first protective film, a magneto-optical recording film and a second protective film are sequentially formed on a substrate of the magneto-optical disk of the present invention, and the second protective film is polished. The inner wall of the disk cartridge is approximately parallel to the disk surface on the magnetic head installation side of the magneto-optical disk. This is the configuration provided.

According to the above-described structure, the present invention reduces the dynamic friction coefficient between the surface of the mixed ultraviolet curable resin, the magnetic head, and the slider using the lubricant contained in the mixed ultraviolet curable resin. It makes the glide smooth.

Furthermore, by placing a liner made of conductive non-woven fabric in contact with the mixed UV-curable resin, it is possible to prevent the mixed UV-curable resin from being charged and to prevent dust from being electrostatically adsorbed onto the mixed UV-curable resin. The abrasive and liner contained in the mixed UV-curable resin have the effect of cleaning dust adhering to the surface of the slider, magnetic head, and mixed UV-curable resin, making it possible to achieve stable magnetic head flying. EMBODIMENT OF THE INVENTION Hereinafter, a magneto-optical disk and a disk cartridge according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 (above) is a cross-sectional view showing the schematic structure of a magneto-optical disk and a disk cartridge in an embodiment of the present invention. In FIG.
14 is T
bFeCo magneto-optical recording film (thickness 10100 nm, 15 is a second protective film (thickness 80 nm) composed of ZnS1 Zn5e 5102 or SiN, 3 is alumina fine particles with a particle size of 0.7 μm (10% by weight) as an abrasive , a mixed ultraviolet curable resin containing a mixture of oleyl oleate and n-butyl stearate (10% by weight) as a lubricant (
19 is a slider made of MnZn ferrite; 20 is a magnetic head made of MnZn ferrite attached to one end of the slider 19;
21 is an objective lens, 22 is a laser beam, 23 is a disk rotation drive device, 24 is a disk cartridge, 25 is a liner made of rayon incorporating carbon fiber,
A conductor 26 electrically connects the liner 25 and the ground of the disk drive device.

The operation of the magneto-optical disk according to an embodiment of the present invention constructed as described above will be explained below with reference to FIG. is in contact with the adhesive resin 3.

The lubricant contained in the mixed ultraviolet curable resin 3 oozes out onto the surface of the mixed ultraviolet curable resin 3, and the coefficient of dynamic friction between the mixed ultraviolet curable resin 3 and the slider 19 is 0.2 to 0.
It becomes 4. When the disk rotation drive device 23 is driven, the slider 19 slides smoothly on the mixed ultraviolet curing resin 3. The rotation speed of the disk rotation drive device 23 increases.
When the relative velocity between the slider 19 and the mixed ultraviolet curable resin 3 reaches approximately 1 m/s or more, the sliders 19 and 9-10- and the magnetic head 20 float away from the mixed ultraviolet curable resin 3.

Further, the liner 25 is in contact with the mixed ultraviolet curing resin 3 even when the disk is stationary and rotating.

After the magnetic head 20 floats, the magnetic head 20, objective lens 21, and laser beam 22 are moved to an arbitrary position on the disk by an access drive system (not shown).
The magneto-optical recording film 14 is locally heated by the magnetic head 20.
By applying a modulated current to the head coil (not shown) of the slider, information is written to the magneto-optical recording film 14. The magnetic head 19 and the magnetic head 20 move from flying to sliding and come to rest on the mixed ultraviolet curable resin 3. Changes in the recording and reproducing characteristics of the magneto-optical recording film 14 over time are depicted in FIG. Figure 2 shows the change in the reproduction signal error with respect to the elapsed time when CSS, recording and reproduction are repeated at a rate of 1 time/15 minutes in a dusty environment at 30°C and 80% RH. . In FIG. 2, A is a change in reproduction signal error of a magneto-optical disk according to the conventional configuration (LB is a change in reproduction signal error of a magneto-optical disk according to the configuration of this embodiment).

As is clear from FIG. 2, the increase in errors seen in the conventional example is not observed l,%. The electrostatic adsorption of dust onto the UV hardening resin 3 is reduced, and the abrasive contained in the mixed UV hardening resin 3 cleans the dust adhering to the slider 19 and the magnetic head 20, and this cleaned dust is trapped in the liner 25. Slider 19, magnetic head 20, and mixed ultraviolet curable resin 3
It is designed to prevent re-adhesion to the top.
0 is now able to perform stable floating running,
This is because the magnetic field applied to the magneto-optical recording film 14 by the magnetic head 20 is stabilized.

The effectiveness of the polishing ml lubricant contained in the mixed ultraviolet curable resin 3 in preventing the increase in playback signal errors was investigated in detail. C8S was recorded at a rate of 1 time/15 minutes in a dusty environment at 30°C and 80% RH. Changes in playback signal error after 10,000 hours of playback are expressed as (UV curable resin) P [(abrasive) X (lubricant) Y]
1-P, are shown in FIGS. 3 to 5.

In Figure 3, the vertical axis is the reproduction signal error, the horizontal axis is the composition ratio P of the ultraviolet curable resin 3, and in Figure 4, the vertical axis is the reproduction signal error, and the horizontal axis is the composition ratio X of the abrasive. In FIG. 5, the vertical axis represents the reproduction signal error, and the horizontal axis represents the composition ratio Y of the lubricant.

Missing number! The manner in which errors increase in FIGS. 3 to 5 will be explained.

In Fig. 3, an increase in errors is seen when the composition ratio P is 0.6 or less. This is because the mixed UV curable resin 3 will peel off.Place the slider 1 on the peeled part of the mixed UV curable resin 3.
When the second protective film 15 comes into contact with the slider 9, the slider 19 comes into contact with the second protective film 15. The second protective film 15 is a thin film with low crush resistance, and the slight contact of the slider 19 causes the second protective film 1 to
5 peels off and the protective function decreases. This is because the coercive force of the magneto-optical recording film 14 decreased.

In addition, an increase in errors is observed when the composition ratio P is 0.9 or more (Due to lack of lubricity and abrasiveness, the mixed ultraviolet curable resin 3 is scraped off by contact with the slider 19, and this cutting dust adheres to the slider 19. Slider 19
This is because the flying position of the magnetic head 20 changes irregularly and the magnetic field strength on the magneto-optical recording film 14 becomes unstable. The reason why an increase in errors is observed below 0.05 is due to a lack of flying stability of the magnetic head 20 due to insufficient polishing properties.

Furthermore, an increase in errors is observed when the composition ratio

-13=4- In Figure 5, the reason why measurement data is missing when the composition ratio Y is less than 0.05 is due to lack of lubricity in magnetic head 2.
This is because measurement was impossible due to the adsorption of UV curable resin 3 and UV curable resin 3. Also, when the composition ratio Y is 0.95 or more, an increase in errors is seen (a large amount of lubricant adheres to the slider 19 and the liner 25,
This is because irregular vibrations occur when the magnetic head 20 flies, and the flying height of the magnetic head 20 changes irregularly. In this case, the adsorption between the mixed ultraviolet curable resin 3 and the magnetic head 20 occurs, albeit unsteadily.

As described above, according to this embodiment, the first protective film 13, the magneto-optical recording layer 14, and the second protective film 15 are sequentially formed on the substrate 1, and alumina fine particles are applied as an abrasive on the second protective film 15.
A mixed ultraviolet curable resin 3 containing a mixture of oleyl oleate and n-butyl stearate as a lubricant was formed.
The inner wall of a disk cartridge that is approximately parallel to the disk surface on the magnetic head installation side of a magneto-optical disk? To install a disk cartridge equipped with a liner made of a nonwoven fabric incorporating carbon fibers, the composition range of the mixed ultraviolet curable resin provided on the second protective film 15 is set to (UV curable resin) P [(abrasive) X (lubricant) Y]
1-0 indicated by P, 6≦P≦0.9, 0.05≦X≦0.95.0, 0
By setting the weight ratio in the range of 5≦Y≦0.95, it is possible to provide a magneto-optical disk and a disk cartridge that can realize a stable recording bias magnetic field.

In this example, the material of the slider 19 is MnZn ferrite. Alternatively, the surface of the slider 19 is not damaged even when glass having a hardness lower than that of ceramics is used.

In this example, when the thickness of the mixed ultraviolet curable resin 3 is 5 μm (when the thickness of the mixed ultraviolet curable resin 3 is Hl, the range of 1 μm≦H1≦505-6-μm) ( Dai: A similar effect can be achieved.

The particle size of the abrasive such as alumina fine particles, ZrO2 fine particles, and 5i02 fine particles used in this example (0.2 μm when the thickness of the mixed ultraviolet curable resin 3 is Hl and the particle size of each fine particle is R1) Even within the range of ≦R1≦H1 (Dai), similar effects can be obtained.

In addition, in this example, stearic acid n-butyl sterate was used as the lubricant mixed in the mixed ultraviolet curable resin 3. The lubricant was a combination of one or more of lauric acid, myristic oleic acid, and stearic acid. A similar effect can be obtained using a mixture with n-butyl stalate.

In this embodiment, a reflective film is provided on the second protective film 15, and the mixed UV curable resin 3 is coated on the second protective film 15. Similar effects can be obtained even in this configuration.

In this embodiment, the magneto-optical recording film 14 and the reflective film are arranged between the first protective film 13 and the second protective film 15. A similar effect can be obtained with a structure provided between the protective films 15.

Furthermore, in this embodiment, carbon fiber is used as the conductive material incorporated into the liner 25.A similar effect can be obtained by using a thin wire made of aluminum or starch instead.

In this embodiment, the force applied by directly applying the mixed ultraviolet curable resin 3 onto the second protective film 15 (between the second protective film 15 and the mixed ultraviolet curable resin 3, for example, an interlayer film such as an ultraviolet curable resin) is applied. The same effect as that of this embodiment can be obtained even when intervening.

Effects of the Invention As described above, the present invention includes sequentially forming a first protective film, a magneto-optical recording layer, and a second protective film on a substrate, placing the second protective film on top, and placing a mixed ultraviolet curable resin mixed with an abrasive and a lubricant. pitching method
A mixed ultraviolet curable resin containing an abrasive and a lubricant is placed on the second protective film 15.The composition range is (UV curable resin)P[(abrasive)X(lubricant)7-Y] 1-0 indicated by P, 6≦P≦0.9, 0.05≦X≦0.95.
The weight ratio range is 0, 05≦Y≦0.95, and the disk cartridge inner wall Q is approximately parallel to the disk surface of the magneto-optical disk.The disk cartridge is equipped with a liner made of conductive nonwoven fabric toward the side where the magnetic head is installed. By providing a mixed ultraviolet curable resin, the dust attached to the slider and the magnetic head can be prevented from re-adhering, the magnetic head can fly stably, and the magnetic field can be applied to the magneto-optical recording film 14. It is possible to provide a magneto-optical disk with high reliability in recording and reproducing.

[Brief explanation of drawings]

FIG. 1 (Turtle) A cross-sectional diagram showing the general structure of a magneto-optical disk and a disk cartridge in an embodiment of the present invention.
Fig. 2 shows the case where C8S is repeated for a magneto-optical disk and a disk cartridge in an embodiment of the present invention. Fig. 3 shows changes in playback signal error with respect to elapsed time. Fig. 3 shows a case where C8S is repeated for a magneto-optical disk and a disk cartridge in an embodiment of the present invention. Fig. 3 shows a case in which the reproduction signal error changes over time. Changes in playback signal errors after repeating recording and playback for 100 hours with C8S at a rate of 1 time/15 minutes are as follows: (UV curable resin) P [(abrasive) X (lubricant) Y] 1-P, Figure 4 shows the reproduction signal error after 10,000 hours of C8S recording and reproduction at a rate of 1 time/15 minutes in a dusty environment at 30°C and 80% RH. Figure 5 shows the change in composition ratio X under a dusty environment at 30°C and 80% RH.
Figure 6 is a cross-sectional diagram showing the structure of a conventional magneto-optical disk, showing the change in reproduction signal error with respect to composition ratio Y after repeating C8S recording and reproduction for 10,000 hours at a rate of 1 time/15 minutes. It is. 1... Substrate, 3... Ultraviolet curable resin 11...
・Glass substrate, 12...UV curable resin WL 1
3...First protection! 14... Magneto-optical recording wL 1
5...Second protection K 16...Crash prevention LL
17... Fluorinated carbon oil, 19... Slider, 20... Magnetic head, 21... Objective lens, 7:, 22... Laser 9-(a)- 23... Disk rotation Drive device 24...Disk cartridge, 25...Linus 26...Connection

Claims (1)

Scope of Claims: (1) A first protective film, a magneto-optical recording film, and a second protective film are sequentially formed on a substrate, and a mixed ultraviolet ray containing an abrasive and a lubricant is cured on the second protective film. A magneto-optical disk characterized by being equipped with a magnetic resin. (2) When the composition ratio of the mixed ultraviolet curable resin is represented by the general formula (UV curable resin)P[(abrasive)X(lubricant)Y]1-P, 0.6≦P≦0. 9, 0.05≦X≦0.95, 0.0
The magneto-optical disk according to claim 1, characterized in that the weight ratio is in the range of 5≦Y≦0.95. (3) A disk cartridge characterized in that a liner made of an electrically conductive nonwoven fabric is provided on the inner wall of the disk cartridge that is substantially parallel to the disk surface on the side where the magnetic head of the magneto-optical disk is installed.