JPH117657A - Optical recording medium, optical head and optical recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the surface of a recording medium from being damaged by collision between a floating optical head loaded with a solid immersion lens and a recording medium. SOLUTION: An optical magnetic recording medium 400 is successively provided with a reflection layer 55, first dielectric layer 54, recording layer 53, and second dielectric layer 52 on the substrate 56, with a recording or reproducing light beam emitted from the second dielectric layer 52 side. On the dielectric layer 52, a diamond-like carbon layer 51 is formed which has self-lubricity. The optical head is constituted of a floating slider to which a solid immersion lens is attached. A protective lens with self-lubricity can also be formed on the face oppositely facing the optical recording medium on the bottom of the slider. With the optical head changing in its floating position and coming into contact with the surface of the optical recording medium, the optical head skids on the surface, reducing the possibility of scratches from sliding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head using a solid immersion lens and an optical recording medium on which recording and reproduction are performed using the same, and more particularly, to an optical head using a solid immersion lens and an optical head. The present invention relates to an optical head and an optical recording medium having improved sliding resistance with respect to a recording medium, and an optical recording apparatus equipped with the optical head.

[0002]

2. Description of the Related Art In recent years, an optical recording apparatus has been used as an information recording apparatus capable of recording large-capacity data at a high density and rapidly reproducing the data in order to cope with the multimedia of the information recording apparatus. This optical recording apparatus uses a read-only disc in which information is stamped on the disc at the time of manufacturing the disc, such as a CD or a laser disc, and is capable of only reproducing information, or a single recording such as a CD-R. As a recording medium, there are a type using a write-once type disk that can be used, and a type using a rewritable type disk on which data can be rewritten and erased many times using a magneto-optical recording method or a phase change recording method.
In these optical recording devices, data recording / reproduction is performed using a light spot in which laser light is narrowed down to the diffraction limit by a lens. Assuming that the wavelength d of the laser is λ and the numerical aperture of the lens is NA, d = λ
/ NA (edited by Yoshito Tsunoda, "Basics and Applications of Optical Disk Storage": The Institute of Electronics, Information and Communication Engineers ((199
5), P65).

In order to record information on an optical recording medium at a higher density, it is necessary to reduce the size of a recording laser spot to form minute pits and magnetic marks. In order to reduce the light spot, the laser wavelength (λ) can be reduced from the above equation or the numerical aperture of the lens (N
A) may be increased. Currently used semiconductor lasers for reproducing optical disks mainly have wavelengths of 780 to 680.
and a shorter wavelength 650 nm orange laser is a digital versatile disk (DVD-RO).
M) and the like. However, a short-wavelength laser emitting green and blue light having a shorter wavelength than the orange laser is still under development, and there is a limit in reducing the spot size by reducing the laser wavelength.

On the other hand, the numerical aperture (NA) of a lens is expressed as follows:
θ, which is smaller than 1. Currently used lenses have an NA of about 0.5, and even if NA = 0.9 which is theoretically close to the limit, the laser spot size can be reduced to at most 1 / 1.8. On the other hand, when the NA is increased, the depth of focus of the lens system becomes shallow, and a problem arises in that the control system for maintaining the focus on the recording surface becomes complicated. Therefore, the NA cannot be increased unnecessarily. The maximum for optical recording devices is NA
= 0.6 lens is used.

[0005] A solid immersion lens (Solid Immersion Lens) to reduce the spot size of laser light
Has been proposed (Nikkei Electronics, 686, pp. 13-14, 1997.4.7). As shown in FIG. 2 (a), when a hemispherical solid immersion lens is used and a laser beam is perpendicularly incident on the lens surface, an equivalent NA of the optical system is obtained.
Is n × N where n is the refractive index of the solid immersion lens.
A. In addition, as shown in FIG.
er Spherical) When a solid immersion lens is used to cause a laser beam to be focused on the bottom surface of the super-hemispherical lens, the equivalent NA is n ² × NA. When a solid immersion lens is made of glass, the refractive index of the glass is about 1.8, so when a hemispherical solid immersion lens is used, the spot size is 1 unit.
/1.8, and 1 / 3.2 for a super hemispherical solid immersion lens, respectively, as compared with the case where a normal objective lens is used.

In the case where a solid immersion lens is used, in this technique, near-field (Near Field) light leaching from the solid immersion lens is used for recording and reproduction, so that the distance between the solid immersion lens and the recording film is wide. However, it is necessary to reduce the wavelength to about 1/4 of the laser wavelength. This value is
170n when using a red laser with a wavelength of 680nm
m, which is much smaller than the distance of several mm between the optical head and the optical recording medium of a normal optical recording apparatus. Therefore, when a solid immersion lens and near-field light are used in combination, it is necessary to use a floating slider as used in a magnetic head of a fixed magnetic disk (hard disk).

FIG. 3 shows an example of the structure of an optical head for a magneto-optical recording medium using a flying type slider according to the present invention. The optical head includes a floating slider 102, an objective lens 71,
A solid immersion lens 100 and a recording magnetic field generating coil 104 are incorporated. In a normal magneto-optical recording device, light is applied to a recording layer through a transparent substrate of a magneto-optical recording medium. However, in the optical head using the solid immersion lens, since the distance between the solid immersion lens and the recording layer is limited as described above, the magneto-optical recording medium has a reflective layer, a first dielectric layer,
It is necessary to adopt a structure in which the magneto-optical recording layer and the second dielectric layer are laminated in this order, and to irradiate recording and reproduction light from the second dielectric layer side. Further, since the flying type slider employs a CSS (Contact Start and Stop) system like the magnetic head, the surface of the magneto-optical recording medium needs a protection and lubrication layer that can withstand CSS.

In a normal optical disk, the surface of the recording film opposite to the substrate is coated with an ultraviolet-curable resin or a Si resin that cures in the atmosphere to protect the recording film, thereby forming a protective film of several μm to several tens of meters. In the method using the solid immersion lens and the near-field light, the resin protective film is thicker than the oozing distance of the near-field light.
It cannot be formed on a dielectric layer. Therefore, in this method, the recording / reproducing optical head moves about 100 nm above the second dielectric film, which is the uppermost layer, similarly to the fixed magnetic disk device. It may come into contact with the second dielectric film and damage its surface.

[0009]

The uppermost second dielectric film of the magneto-optical recording medium is formed of a hard material such as silicon nitride, silicon oxide, aluminum nitride, silicon carbide, etc. 100 nm, which is 2 to 5 times thicker than the magnetic disk, and the flying height of the recording / reproducing optical head is 10 when a solid immersion lens and near-field light are used.
The scratches entering the surface of the dielectric film due to irregular sliding caused by the fluctuation of the attitude of the optical head do not become so deep as to reach the recording film, because it can be increased to about 0 to 150 nm, which is about 2 to 3 times higher than that of the magnetic disk. In the traveling direction of the optical head, there are mainly cases in which a scratch is formed as a rubbing streak having a width of about several μm to several hundred μm and a depth of about several tens nm. In an optical disk such as a normal magneto-optical disk, the size of the laser spot on the substrate surface is at least about 1 mm because reproduction is performed through a transparent substrate, and scratches of several μm to several tens μm on the substrate surface are hardly used for recording and reproduction. No problem. However, in the method using a solid immersion lens and near-field light, the exudation of laser light narrowed down to the diffraction limit is used, so that even a scratch with a width of several μm generated on the dielectric film surface has an edge portion of the scratch. In this case, there is a problem that the amount of reflected light, that is, the amount of reproduced light fluctuates due to interference at the point, and a reproduction error easily occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and it is an object of the present invention to make it difficult for a surface of a recording medium to be damaged by collision between an optical head and the recording medium. It is an object of the present invention to provide an optical recording medium in which even if a scratch is made, the scratch does not cause an error during reproduction.

Further, the present invention makes it difficult for the optical head and the recording medium to be damaged by the collision between the recording medium and the surface of the recording medium. And a recording / reproducing apparatus for an optical recording medium using the same.

[0012]

According to a first aspect of the present invention, a light having a reflective layer, a recording layer, and a dielectric layer on a substrate and irradiated with information recording or reproducing light from the dielectric side is provided. In a recording medium, there is provided an optical recording medium, wherein a solid protective layer having self-lubricating properties is formed on the dielectric layer.

The optical recording medium of the present invention has a self-lubricating solid protective layer on the dielectric layer facing the optical head.
Accordingly, even if the floating position of the optical head fluctuates and slides on the surface of the optical recording medium, the optical head slides on the surface of the recording medium, so that the optical head does not get caught on the surface, and sliding scratches are less likely to occur. In addition, since the protective film having self-lubricating property is easily peeled off in a layer, even if the optical head collides (slides) with the recording medium vigorously, the protective film is first peeled off in a layered manner, so that the optical head and the dielectric layer are peeled off. The generation of sharp scratches is prevented.
Therefore, it is possible to suppress errors and defects in a reproduction signal caused by a scratch on the reproduction light irradiation side surface of the optical recording medium. The optical recording medium of the present invention may further include a dielectric layer between the reflective layer and the recording layer.

According to a second aspect of the present invention, there is provided an optical head for mounting a solid immersion lens in a flying type slider and recording or reproducing an optical recording medium. An optical head is provided in which a solid protective layer having self-lubricating properties is formed on the facing surface.

The optical head of the present invention has a self-lubricating solid protective layer on at least the surface of the flying type slider facing the optical recording medium. Accordingly, even if the floating position of the optical head fluctuates and the optical head comes into contact with the surface of the optical recording medium, the optical head slides on the surface of the recording medium, so that the optical head does not get caught on the surface and the optical recording medium surface or the optical head can be prevented. Sliding scratches are less likely to occur on the sliding surface of. Also, since the protective film having self-lubricating properties is easily peeled off in a layered manner, even if the optical head and the recording medium slide violently, the protective film is firstly peeled off in a layered form so that the optical head or the optical recording medium surface is sharp. The occurrence of scratches is suppressed. Therefore, an error in the reproduction signal caused by a scratch on the reproduction light irradiation side surface of the optical head or the optical recording medium,
Defects are reduced.

In the present invention, "having self-lubricating properties" means that the material itself has lubricating properties alone, such as graphite and molybdenum disulfide.
Examples of the substance constituting the protective film having self-lubricating properties formed on the optical recording medium and optical head of the present invention include inorganic substances such as carbon film, molybdenum disulfide, lead oxide, cadmium oxide and boron oxide, and polytetrafluoroethylene. And polymer compounds such as polyethylene and nylon. Of these, since the recording film of the optical recording medium is usually formed by a physical vacuum film forming method such as sputtering, it is preferable that the protective film is also easily formed by the physical vacuum film forming method. Further, since it is desirable that the protective film transmit the laser light without attenuating during recording and reproduction, a carbon film or a diamond-like carbon film having a small extinction coefficient is preferable.

In the optical recording medium of the present invention, if the refractive index of the self-lubricating protective film and the refractive index of the dielectric layer in contact with the protective film are significantly different, the laser light is effectively reflected at the interface between the two. Since laser light is not used, the absolute value of the difference between the refractive index of the protective film and the refractive index of the dielectric layer is 0.5.
It is desirable to be within. Further, the extinction coefficient of the protective film is desirably set so that the absolute value of the difference between the extinction coefficient of the dielectric layer and the extinction coefficient of the dielectric layer is within 0.2 in order to suppress the attenuation of laser light.

In the optical recording medium and the optical head of the present invention, when a carbon film is used as a protective film having self-lubricating properties, the carbon film contains hydrogen, nitrogen, fluorine, silicon, etc. to thereby improve the hardness of the film. And the optical characteristics may be controlled. The thickness of the self-lubricating protective film is
5 nm or more and preferably within 50 nm
If it is less than 10, it is difficult to obtain sufficient sliding characteristics. Although there is no upper limit of the thickness of the protective film with respect to the sliding characteristics, if the thickness is large, it causes optical loss, and the distance between the solid immersion lens on the optical head and the recording layer of the recording medium is limited due to the use of near-field light. Since it is necessary to set the thickness of the protective film having the self-lubricating property to 50 nm, it is necessary to set the thickness of the protective film having the self-lubricating property to approximately 1/4 of the laser wavelength to be used.

In the case where a protective film having self-lubricating property is provided on the optical head, it is sufficient to form the protective film only on a portion facing and sliding with the optical recording medium. If a protective film is not formed on the solid immersion lens portion, the self-lubricating protective film provided on the optical head may have any light transmittance. Conversely, when a protective film having self-lubricating properties is also formed on the solid immersion lens portion, a light-transmissive material should be used similarly to the protective film having self-lubricating properties formed on the top layer of the recording medium. Is desirable.

A lubricating layer may be further formed on the self-lubricating solid protective layer. The lubricating layer has a group selected from at least one of a hydroxyl group, a carboxyl group, an ester group, an amino group, and a piperonyl group at at least one of molecular terminals, and has a molecular weight of 100.
It may contain from 0 to 8000 perfluoropolyethers.
In order to further improve the lubricity of the perfluoropolyether, the molecular weight is preferably 1,000 or more, and in order to suppress an increase in viscosity, the molecular weight is preferably 8,000 or less. CSS
In order to further enhance the durability, after applying a perfluoropolyether lubricant on the protective layer, the optical recording medium is subjected to a heat treatment at a temperature of, for example, 50 to 120 ° C. to thereby convert the perfluoropolyether lubricant to the protective layer. Can be fixed on top. Instead of or in addition to the heat treatment, ultraviolet light, for example, ultraviolet light having a wavelength of 254 nm may be irradiated. By using both of them, it is possible to further promote the fixation of the perfluoropolyether lubricant on the protective layer. Even if the flying type slider slides in the CSS mode due to the fixed lubricant component, the slider does not directly contact the protective layer, and the durability of the optical recording medium can be improved. In addition, the lubricant diffuses on the surface of the protective layer such as carbon by heat energy due to heat treatment and / or ultraviolet irradiation, so that the lubricity of the lubricant is improved, and water and the lubricant molecules existing on the surface of the protective layer are removed. Exchange and adsorption increase the adhesion of the lubricant, and as a result, the lubrication effect is improved.

The lubricating layer can be formed of a mixed lubricant (two-component lubricant) containing a lubricant having an amide group at a molecular terminal and a lubricant which is liquid at normal temperature. When this mixed lubricant is used, the solid protective layer having self-lubricating properties advantageously has a carboxyl group on its surface. This is because the carboxyl group formed on the surface of the protective layer and the amide group of the lubricant form an acid-base bond to form a strong lubricating layer. Further, by including a lubricant that is liquid at normal temperature, lubricity at high temperature is improved. Further, this mixed lubricant is advantageous because it is soluble in an inexpensive and highly versatile solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone, and methyl isobutyl ketone. In order to introduce a carboxyl group on the surface of the self-lubricating solid protective layer, the solid protective layer is coated with ultraviolet light, for example, λ = 185.
nm and 254 nm ultraviolet light or plasma treatment in an oxygen atmosphere. When a carboxyl group is introduced, the composition ratio of oxygen / carbon (O / C) on the surface of the solid protective layer having self-lubricating property is set to 0.1 or more in order to improve CSS durability. More preferred.

The optical recording medium of the present invention may have a landing zone for a flying slider on the inner or outer periphery. It is advantageous to have dot-like projections with a height of 10 to 100 nm in the landing zone at an area ratio of 0.1% to 5.0%. If the height of the dots is 10 nm or more, the static frictional force can be reduced. If the height is 100 nm or less, the reduction in the mechanical strength of the dots can be suppressed. Also,
When the area ratio of the dots is 0.1% or more, the pressure applied to the dots can be reduced, and the abrasion of the dots due to CSS is reduced. If the area ratio of the dots is 5.0% or less, the contact area between the slider and the optical recording medium is reduced, and the static friction force is reduced.

The optical recording medium of the present invention is a CD, CD-RO
M, like a DVD-ROM, whether there are uneven pits or holes,
A read-only optical recording medium that reproduces information based on the difference in reflectance between the crystalline layer and the amorphous phase, or a write-once type that records holes in a laser on an inorganic layer such as an organic dye layer or a Te compound such as a CD-R. Optical recording media, TbFeCo or DyF
A magneto-optical recording medium having a recording layer of an alloy layer of a rare earth metal and a transition metal such as eCo, and a recording film such as a Ge alloy or an In alloy are reversibly changed between a crystalline phase and an amorphous phase by light irradiation. Any optical recording medium such as a rewritable optical recording medium such as a phase-change optical recording medium that can be made to operate can be used.

The substrate used in the optical recording medium of the present invention comprises:
In addition to polycarbonate, polyolefin, polymethyl acrylate, polystyrene, nylon and other resins,
A disk substrate made of metal such as glass, silicon, thermally oxidized silicon, Al, or Ti can be used.

In the present invention, the protective layer having self-lubricating properties
The effect of the present invention can be achieved by forming at least one of the surface of the optical head facing the optical recording medium or the surface of the optical recording medium facing the optical head,
It is more preferable to form a self-lubricating protective film on the surfaces of the optical head and the recording medium that face each other.

According to a third aspect of the present invention, there is provided an optical recording apparatus for recording or reproducing information on an optical recording medium, comprising an optical head, wherein the optical head comprises a floating slider and a floating slider. An optical recording device comprising: a solid immersion lens mounted thereon; and a solid protective layer having self-lubricating properties formed on at least a surface of the flying slider facing the optical recording medium. .

The optical recording apparatus of the present invention has an optical head having a self-lubricating solid protective layer formed on at least the surface of the flying slider facing the optical recording medium, so that the floating position of the optical head varies. Therefore, even if the optical head slides on the surface of the optical recording medium, sliding scratches hardly occur on the surface of the optical recording medium or the sliding surface of the optical head. Therefore, when an optical recording medium is reproduced using the optical recording apparatus of the present invention, a reproduced signal has very few errors and a good C / N can be obtained.

The optical recording device of the present invention can be a device for recording / reproducing a magneto-optical recording medium.
The optical head includes a magnetic field applying unit such as a magnetic coil.

In the optical head and the optical recording apparatus of the present invention, the solid immersion lens can be a hemispherical solid immersion lens or a super hemispherical solid immersion lens. As an optical recording medium recorded or reproduced by the optical recording device of the present invention, a reflective layer on a substrate,
An optical recording medium having a first dielectric layer, a recording layer, and a second dielectric layer sequentially and irradiated with information recording or reproduction light from the dielectric side, and having a self-lubricating property on the second dielectric layer. An optical recording medium having a solid protective layer formed thereon is preferred. Thereby, even if the floating position of the optical head fluctuates and the optical head slides on the surface of the optical recording medium, the occurrence of sliding scratches on the surface of the optical recording medium or the sliding surface of the optical head is further suppressed. . The aforementioned lubricating layer may be applied on the protective layer.

According to a fourth aspect of the present invention, on a substrate:
An optical recording medium having a reflective layer, a recording layer, a dielectric layer, a protective layer, and a lubricating layer and irradiated with recording light or reproduction light from the lubricating layer side, wherein the lubricating layer is at least one of molecular terminals. Provided is an optical recording medium having a group selected from at least one of a hydroxyl group, a carboxyl group, an ester group, an amino group, and a piperonyl group at a terminal and containing a perfluoropolyether having a molecular weight of 1,000 to 8,000. You. By providing the above lubricant, CSS
The durability can be improved, the friction when the optical head slides on the optical recording medium can be reduced, and the occurrence of scratches can be suppressed.
A dielectric layer may be further provided between the reflective layer and the recording layer.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and examples of an optical recording medium, an optical head and an optical recording apparatus according to the present invention will be specifically described below with reference to the drawings.

Embodiment 1 FIG. 4 is a sectional view of a magneto-optical recording medium 400 showing one specific example of the optical recording medium of the present invention. The magneto-optical recording medium 400 having this structure was manufactured by the following method. First, polycarbonate was injection-molded with an injection compression molding machine to produce a polycarbonate resin disk substrate 56. Substrate 56
Had a diameter of 95 mm, a thickness of 1.2 mm, and an inner diameter of 25 mm. Next, the AlTi alloy reflection layer 55 was formed on the substrate 56 by using an in-line DC magnetron sputtering apparatus.
50 nm, and the silicon nitride layer 54 (first dielectric layer)
0 nm, 25n of TbFeCo alloy layer 53 (recording layer)
m, the silicon nitride layer 52 (second dielectric layer) is
Each was formed in a film thickness of nm. Next, a diamond-like carbon layer 51 having a thickness of 20 nm was formed as a self-lubricating protective film by the same magnetron sputtering apparatus.

In the above sputtering, the AlTi reflective film 55 is formed by using an AlTi alloy target having a Ti content of 2 at% and using an Ar gas as a sputtering gas at a flow rate of 8%.
Flow at 0 sccm (vacuum degree 1.2 Pa), input power 2
A film was formed at kW. The silicon nitride layers 54 and 52 (first and second dielectric layers) are formed using
A film was formed at an input power of 2 kW by using a N ₂ mixed gas (mixing ratio: 1: 1) at a flow rate of 80 sccm (vacuum degree: 1.2 Pa). TbFeCo alloy layer 53, Tb ₂₃ Fe ₆₇ Co ₁₀
(At%) using an alloy target and Ar gas at a flow rate of 10
The film was formed at a flow rate of 0 sccm (a degree of vacuum of 1.5 Pa) and a power of 500 W. The diamond-like carbon layer 51 uses an amorphous carbon target,
An Ar-methane mixed gas (mixing ratio 1: 1) was supplied at a gas flow rate of 30.
Flow at 0 sccm (vacuum degree 5 Pa), input power 2 kW
Was formed. At this time, 200 W of RF power was applied to the substrate side, and a negative bias voltage was also applied to the substrate side, so that bias sputtering was performed.

Embodiment 2 FIG. 5 is a cross-sectional view of a main part of a specific example of an optical head 500 according to the present invention. The optical head 500 includes a flying slider 10.
2. Solid immersion lens 100, magnetic coil 104
And a protective film 105 formed on the surface (sliding surface) of the flying slider 102 facing the optical recording medium. The optical head 500 can be manufactured by the following method. First, in order to produce the floating type slider 102, prepared Al ₂ O ₃ -TiC composite ceramic wafer, the surface of the one, to form a sliding surface of the concave-convex pattern as shown in FIG. This pattern is formed by machining or etching.

After the pattern is formed, an extra portion is cut off to cut out the slider 102 of the optical head, and the diamond-like carbon protective film 10 is formed by sputtering in the same manner as the protective film is formed on the magneto-optical recording medium on the pattern forming surface.
5 is formed with a thickness of 10 nm. Next, holes for installing the solid immersion lens 100 and the recording magnetic field generating coil 104 are formed by machining or etching, and the solid immersion lens 100 and the magnetic coil 104 are formed there.
Is installed as shown in FIG. Here, the solid immersion lens 100 is a super hemispherical solid immersion lens.

The sliding surface pattern shown in FIG. 6 is provided for controlling the air flow so that the flying characteristics of the optical head are stabilized. Such patterns have been studied in various ways, and can be designed according to the size and flying height of the optical head. In this embodiment, the slider 102 is a negative pressure / positive pressure type slider. As can be seen from the bottom view, the left side view, and the cross-sectional view taken along the line AA of the slider 102 in FIG. 6, the bottom surface 81 of the slider 102 slightly protrudes from the bottom surface 81 (projects forward in FIG. 6) and is indicated by an arrow in the drawing. A protrusion 80 is formed extending in the direction of travel of the disc (magneto-optical recording medium). The convex portion 80 is formed so that its width (length in a direction perpendicular to the disk traveling direction) changes along the disk traveling direction. The airflow generated when the disk (magneto-optical recording medium) is rotationally driven by a turntable or the like with respect to the slider 102 passes between the protrusions 80 as shown by the arrow B. At this time, the airflow is compressed in a narrow region sandwiched between the wide (on the AA line) portions 80a of the convex portion 80, and then diffuses into a wide region sandwiched between the narrow portions 80b, so that the pressure decreases. . Due to the reduced pressure (negative pressure), a suction force from the disk acts on the slider 102, while a buoyancy due to the rotation of the master acts on the slider 102. A constant spacing between them can be maintained. For details of the negative pressure and positive pressure combined type slider, for example,
Reference can be made to the column of application examples to magnetic disks described in “MR / GMR Head Technology”, page 112 (Trikes Publishing).

The magneto-optical recording medium 400 and the optical head 500 manufactured in the first and second embodiments are incorporated in an optical recording apparatus as shown in FIG. The optical head 500 is incorporated at the tip of a swing arm 35 attached to the rotary actuator 37. The objective lens 34 for focusing the laser beam on the solid immersion lens in the optical head 500 is incorporated in the same rotary actuator 37 and is fixed on an arm 36 that is mechanically fixed and moves together with the swing arm 35. The swing arm 35 and the arm 36 can be formed of a leaf spring or the like as in the case of the magnetic disk drive. As shown in FIG. 8, the objective lens 34 always focuses on the bottom surface of the solid immersion lens 100.
A drive mechanism (voice coil type actuator) using a coil 44 and a magnet 45 for maintaining a constant interval between the solid immersion lens 100 and the solid immersion lens 100 is provided. The focusing servo for keeping the laser beam 46 always focused on the bottom surface of the solid immersion lens uses the same method as the focusing servo used to keep the laser beam constantly focused on the optical disc surface in a normal optical storage device. Then, a focus error signal may be generated for the return light from the solid immersion lens by an astigmatism method, a knife edge method, or the like, and a focusing servo may be applied based on this signal.

During recording or reproduction, the solid immersion lens 100 is separated from the surface of the magneto-optical recording medium 400 by a predetermined distance, that is, 40 nm to 60 nm, and recording or reproduction is performed by bleeding of near-field light. May be controlled by controlling the height position of the bottom surface (81) of the flying slider 500. This control is performed, for example, by controlling the pattern (see FIG. 6) formed on the bottom surface of the flying slider 500, the number of rotations of the disk, and the angle (skew) between the disk and the slider, as in the case of the magnetic disk drive. It can be realized by designing or adjusting the distance (flying amount) to the above-mentioned predetermined distance with respect to the disk surface.

FIG. 9 shows a specific example of the entire optical system of the optical recording apparatus of the present invention. FIG. 9 shows an optical system in the case of a magneto-optical recording device. In FIG. 9, the same optical system of a drive for recording / reproducing a normal magneto-optical recording medium can be used as the fixed optical system. That is, the laser light emitted from the laser light source 57 is
a, 59b, pass through the beam splitter 60,
After being reflected at 0,69, it is incident on the objective lens 71, is further condensed by the solid immersion lens 100, and focuses on the bottom surface of the solid immersion lens 100. Light oozing from the bottom surface of the solid immersion lens 100 reaches the recording layer of the magneto-optical recording medium 400 and forms a magnetic mark according to a recording signal. During recording, the magneto-optical recording medium 4
A recording magnetic field is applied to 00, an optical modulation method,
Recording can be performed by any of the magnetic field modulation method and the optical magnetic field modulation method.

At the time of reproduction, the reflected light from the magneto-optical recording medium 400 is reflected by the mirrors 69 and 70, then reflected by the beam splitter 60, and split by the beam splitter 61 into light directed to the two beam splitters 64 and 65. Is done.
The reflected light that has entered the beam splitter 65 is further split there and enters the focusing detection detector 68c and the tracking signal detection detector 68d, respectively. The reflected light that has passed through the half-wave plate 63 and the lens 67 and has entered the beam splitter 64 enters photodetectors 68a and 68b that detect light of polarization components orthogonal to each other, and detects a reproduction signal. .

When the phase change method and the write-once method are used, the same optical system of a drive for recording / reproducing the phase change type optical recording medium and the write-once type optical recording medium such as a CD-R may be used. In these optical systems, only one detector for signal detection is required, and the beam splitter 64 immediately before the detector is not required.

Comparative Example 1 A magneto-optical recording medium was manufactured in the same manner as in Example 1, except that the protective film 51 was not formed on the silicon nitride film 52.

Comparative Example 2 An optical head was manufactured in the same manner as in Example 2 except that the protective film 105 was not formed on the bottom surface of the flying slider 102, that is, on the surface facing the optical recording medium. did.

The effects of the silicon nitride film 52 (second dielectric layer) of the magneto-optical recording medium and the self-lubricating protective film formed on the slider bottom surface of the optical head were examined by the following method. The magneto-optical recording medium and the optical head are assembled into the optical recording apparatus in the combinations shown in Table 1 and randomly set to 100,0 between a radius of 25 mm and a radius of 45 mm.
The optical head was sought 00 times. In Table 1, the magneto-optical recording medium manufactured in Example 1 was denoted by M1, the optical head manufactured in Comparative Example 2 was denoted by H1, and the magneto-optical recording medium manufactured in Comparative Example 1 was denoted by M2 and Example 2. The optical heads were each represented by H2. On an optical recording medium, a laser length gauge and a formatter are combined in advance to form an address signal pattern for positioning with an optical head to be used and a sample servo pattern for performing tracking servo with a track pitch of 0.8 μm, the shortest. Writing was performed with a mark length of 0.4 μm. The rotation speed of the magneto-optical recording medium is 4500 rpm
m. The flying height of the optical head at this time was 50 nm from the surface of the magneto-optical recording medium.

[0045]

Table 1 Optical recording medium Optical head Example 3 M1 H1 Example 4 M1 H2 Example 5 M2 H1 Example 6 M2 H2

For each combination of optical head and medium,
The number of defects before and after 100,000 random seeks of the optical head was measured. Defects were recorded on all tracks (12,500 tracks) with a mark length of 1 between a radius of 30 and 40 mm.
A portion where the amplitude was 65% or less in the magneto-optical signal when a relatively long pattern of μm was written and reproduced was regarded as a defect. In order to prevent dust from the surrounding environment during measurement from becoming a defect that adheres to the medium, the measurement was performed in a measurement room with a cleanness of 100, and the optical recording device used for the measurement was further covered with a clean booth. A measurement was made.

[0047]

Table 2 Number of defects Before random seek After random seek Defect increase rate Example 3 1250 1500 1.20 Example 4 1400 1850 1.32 Example 5 1150 1780 1.54 Example 6 1250 3240 2.59

In the table, the increase rate of defects was determined according to the following equation. Defect increase rate = (number of defects after random seek) / (number of defects before random seek). As can be seen from Table 2, the combination of the optical head without the protective film and the magneto-optical recording medium has the highest defect increase rate. A light irradiation side surface portion of the magneto-optical recording medium corresponding to the location where the defect occurred was examined with an optical microscope and a scanning electron microscope (SEM). As a result, 90% or more of the defect location had a width of several μm to several tens μm.
Traces of rubbing on m were observed. Further, when recording and reproduction were performed with the combination of the optical head and the magneto-optical recording medium of Example 6, the generated scratches were sharpest and sharp. Also, 10
When the sliding surface of the optical head after seeking 000 times was observed with an optical microscope, an extremely large number of scratches were observed in the optical head used in Example 6. On the other hand, in another embodiment 3,
At 4 and 5, scars were hardly observed.

From the above results, it is found that a self-lubricating protective film such as carbon is provided on at least one of the magneto-optical recording medium and the surface of the optical head opposed to the magneto-optical recording medium, so that the seek of the optical head is achieved. It can be seen that the occurrence of scratches caused by the irregular sliding of the head and the magneto-optical recording medium due to the change in the attitude of the head due to the movement of the head can be suppressed, and the defects caused by the scratches can be reduced.

Example 7 An amorphous polyolefin resin disk substrate (outer diameter: 130 mm, center hole diameter: 15 mm, plate thickness) was prepared using an Ni stamper in which grooves and pits were previously formed and an injection compression molding machine.
1.2 mm), and an AlTi alloy reflective layer 55 is formed thereon by using a stationary facing DC magnetron sputtering apparatus.
m, a silicon nitride layer of 20 nm, a TbFeCo alloy layer of 20 nm, and a silicon nitride layer of 150 nm in thickness again,
A diamond-like carbon (DCL) layer having a thickness of 10 nm was formed on the silicon nitride layer as a self-lubricating film by using an ion beam sputtering apparatus.

In the above sputtering, an AlTi reflection film
Reference numeral 55 denotes an AlTi alloy target having a Ti content of 2 at%, a flow rate of 30 sccm (vacuum degree 1.0 Pa) using Ar gas, and a power of 4
A film was formed by sputtering at kW. The silicon nitride layers 54, 52
Using a silicon target with Ar-N ₂ mixed gas (mixing ratio 1: 1), flow rate 80 sccm (vacuum degree 2.5 Pa), input power 4 k
A film was formed by sputtering with W. TbFeCo alloy layer 53 is Tb ₂₃ Fe ₆₇ Co
₁₀ (at%) alloy target was flowed at 80 sccm using Ar gas.
(Vacuum degree: 2.5 Pa) Sputtering was performed under the conditions of an input power of 2 kW to form a film. The DLC layer irradiates the carbon target with Ar ions extracted at an acceleration voltage of 500 V, and irradiates the substrate with a mixed gas of Ar and methane (mixing ratio 3: 1) extracted at an acceleration voltage of 100 V by another ion gun. While forming a film.

After the DCL film is formed, the disk is rotated while pressing a 4000-series wrapping tape against the surface of the disk by air pressure, and a tape cleaning (TC) process is performed to scrape off fine projections on the disk surface. After irradiating with a low-pressure mercury lamp that generates wavelengths of 185 nm and 254 nm for 90 seconds in a perfluorooctane solvent, the main chain is (F ((CF ₂ ) ₃ -O)) _n (where n is A lubricating layer is formed on the DLC film by spin coating using a solution in which a perfluoropolyether-based lubricant having a hydroxyl group at one end is dissolved at a concentration of 0.02% by weight. did.

Example 8 A DCL film was formed on a disk in the same manner as in Example 7
In a perfluorooctane solvent, the main chain is (F ((CF ₂ ) ₃ -O)) _n
(Where n is an integer of 10 to 14) and a solution in which a perfluoropolyether-based lubricant having a carboxyl group at one terminal of the molecule is dissolved at a concentration of 0.02% by weight is spin-coated. A lubricating layer was formed on the DLC film by the method.

Example 9 A DLC film was formed on a disk in the same manner as in Example 7,
In a perfluorooctane solvent, a perfluoropolysiloxane having a main chain of (F ((CF ₂ ) ₃ -O)) _n (where n is an integer of 10 to 14) and having an ester group at one end of a molecule. Using a solution in which an ether lubricant is dissolved at 0.02% by weight,
A lubricating layer was formed on the DLC film by spin coating.

Example 10 On a disk on which a DLC film was formed in the same manner as in Example 7,
In a perfluorooctane solvent, a perfluoropolysiloxane having a main chain of (F ((CF ₂ ) ₃ —O)) _n (where n is an integer of 10 to 14) and having a piperonyl group at one end of a molecule. A lubricating layer was formed on the DLC film by a spin coating method using a solution in which an ether lubricant was dissolved at 0.02% by weight.

Example 11 On a disk on which a DLC film was formed in the same manner as in Example 7,
In a perfluorooctane solvent, the main chain is (-(CF ₂ ) ₂ -O) _n (CF ₂
-O) _m- ), where n is an integer from 9 to 13,
m is an integer of 9 to 13) and a lubricating layer is formed on the DLC film by spin coating using a solution in which a perfluoropolyether-based lubricant having hydroxyl groups at both molecular terminals is dissolved at 0.02% by weight. Was formed.

Example 12 In the same manner as in Example 7, a DLC film was formed on a disk
In a perfluorooctane solvent, the main chain is (-(CF ₂ ) ₂ -O) _n (CF ₂
-O) _m- ), where n is an integer from 9 to 13,
(m is an integer of 9 to 13). A perfluoropolyether-based lubricant having carboxyl groups at both ends of the molecule is used in 0.1.
A lubricating layer was formed on the DLC film by spin coating using a solution dissolved at 02% by weight.

Example 13 A DLC film was formed on a disk in the same manner as in Example 7,
In a perfluorooctane solvent, the main chain is (-(CF ₂ ) ₂ -O) _n (CF ₂
-O) _m- ), where n is an integer from 9 to 13,
m is an integer of 9 to 13) 0.02 perfluoropolyether lubricant having ester groups at both ends of the molecule
DL solution by spin coating method
A lubricating layer was formed on the C film.

Example 14 In the same manner as in Example 7, a DLC film was formed on a disk
In a perfluorooctane solvent, the main chain is (-(CF ₂ ) ₂ -O) _n (CF ₂
-O) _m- ), where n is an integer from 9 to 13,
m is an integer of 9 to 13) A perfluoropolyether-based lubricant having a piperonyl group at both ends of the molecule is used in an amount of 0.0
Using a solution dissolved at 2% by weight, spin coating is used to obtain D
A lubricating layer was formed on the LC film.

Example 15 On a disk on which a DLC film was formed in the same manner as in Example 7,
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and a partially fluorinated ester (C ₁₇ H
_A lubricating layer was formed on the DLC film by a dipping method using a solution in which each of ₃₁ COOC ₂ H ₄ C ₆ F ₁₃ ) was dissolved at 0.04% by weight.

Example 16 A DLC film was formed on a disk in the same manner as in Example 7,
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and a partially fluorinated ester (C ₁₇ H
_A lubricating layer was formed on the DLC film by a dipping method using a solution in which each of ₃₁ COOC ₂ H ₄ C ₆ F ₁₃ ) was dissolved at 0.04% by weight. After forming the lubricant, the disk surface was heated to 100 ° C. using an ultraviolet lamp and cured for 30 seconds.

Example 17 A DLC film was formed on a disk in the same manner as in Example 7,
In a solvent of methyl isobutyl ketone, N, N-dimethylstearylamine (C ₁₈ H ₃₇ -N (CH ₃ ) ₂ ) and a partially fluorinated ester (C ₁₇ H ₃₁ COOC ₂ H ₄ C ₆ F ₁₃ ) which are liquid at room temperature To 0.0
Dip method using a solution dissolved at 4% by weight
A lubricating layer was formed on the LC film.

Example 18 A disk on which a DLC film was formed in the same manner as in Example 7
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and partially fluorinated ester ((CF ₃ ) which is liquid at room temperature
₂ CF (CF ₂ ) ₁₀ CH ₂ CH [OCOC (CH ₃ ) ₂ (C ₆ H ₁₃ )] CH ₂ [OCOC (CH ₃ ) ₂
(C ₆ H ₁₃ )]) A lubricating layer was formed on the DLC film by a dipping method using solutions each dissolved at 0.04% by weight.

Example 19 A DLC film was formed on a disk in the same manner as in Example 7,
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and partially fluorinated ester ((CF ₃ ) which is liquid at room temperature
₂ CF (CF ₂ ) ₁₀ CH ₂ CH (OCOC ₁₇ H ₃₁ ) A lubricating layer was formed on the DLC film by a dipping method using a solution in which each of CH ₂ (OCOC ₁₇ H ₃₁ ) was dissolved at 0.04% by weight. Formed.

Example 20 In the same manner as in Example 7, a DLC film was formed on a disk
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and a partially fluorinated ester ([(C
_{H 3) 2 CH (CH 3} ) CH] 2 C (CH 3) COOCH 2 C 6 F 12 CH 2 0COC (CH 3) [(CH 3)
A lubricating layer was formed on the DLC film by a dipping method using a solution in which HCH (CH ₃ ) ₂ ] ₂ ) was dissolved at 0.04% by weight.

Example 21 A disk on which a DLC film was formed in the same manner as in Example 7
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and a partially fluorinated ester ([(C
H ₃ ) ₂ CH (CH ₃ ) CH] ₂ C (CH ₃ ) COOCH ₂ C ₆ F ₁₃ 0.04
DL by a dipping method using a solution dissolved in
A lubricating layer was formed on the C film.

Example 22 A disk having a DLC film formed thereon in the same manner as in Example 7
Stearylamine (C ₁₈
H ₃₇ -NH ₂ ) and CH ₃ (CH ₂ ) ₁₁₀ (CH ₂ ) ₃ NHCOCF ₂ which is liquid at room temperature
(OC ₂ F ₄ ) ₁₀ (OCF ₂ ) ₁₀ CF ₂ CONH (CH ₂ ) ₃₀ (CH ₂ ) ₁₁ Lubricate the DLC film by dipping using a solution in which each of CH ₃ is dissolved at 0.04% by weight. A layer was formed.

The effect of forming a protective film having self-lubricating properties on an optical recording medium and forming a lubricant layer thereon was examined by the same method as that used in Examples 3 to 6. .
As the optical head, the optical head H1 manufactured in Example 2 and the optical head H2 manufactured in Comparative Example 1 were used. Servo signals are transferred from the stamper during injection molding to the substrate (track pitch 0.4 μm, groove width 0.1 μm, groove depth 60
nm), and address information was obtained from pits previously formed on the substrate by the same method.
The rotation speed of the optical recording medium was 3600 rpm. At this time, the flying height of the optical head was 70 to 80 nm. Examples 7 and 2
With respect to the combination of 0 and the optical heads H1 and H2, the increase / decrease of the number of defects before and after the random seek operation of the optical head 100,000 times was measured. The defect was defined as a portion where the reflected signal from the land portion under tracking was 65% or less, and was measured between a radius of 30 to 40 mm (25,000 tracks).

Table 3 summarizes the results when the optical head H1 is used, and Table 4 summarizes the results when the optical head H2 is used.

[0070]

[Table 3]

[0071]

[Table 4]

In the table, the rate of increase in defects was determined according to the following equation. Defect growth rate = (number of defects after random seek)
/ (Number of defects before random seek). As can be seen from Tables 3 and 4, an increase in defects can be suppressed by providing a lubricating layer on the self-lubricating protective film layer of the optical recording medium. When the surfaces of the optical recording media in Tables 3 and 4 after random seek were examined with an optical microscope and a scanning electron microscope, scars were hardly observed.

Examples 23 to 34 In the same manner as in Example 1, a glass substrate (outer diameter 95 mm, center hole diameter 25 mm,
Board thickness 1mm, track pitch 0.5μm, groove width 0.2μm,
Using a stationary facing DC magnetron sputtering apparatus, an AlTi alloy reflective layer 55 of 50 nm, a silicon nitride layer of 20 nm, a TbFeCo alloy layer of 20 nm, and a silicon nitride layer of 120 nm were formed on the groove with a depth of 70 nm. above, while at the same time to sputter the carbon and Si-containing carbon target in a mixed gas of Ar and CH _4, the negative bias voltage by adding an RF power to the substrate side is applied, the mixing ratio of Ar and CH _4, Si By controlling the content and bias voltage,
A 10-nm self-lubricating film having a refractive index of 1.9 to 2.5 and an extinction coefficient of 0.01 to 1.0 was formed.

The uppermost silicon nitride film has a refractive index of 1.9 to 1.9 by controlling the mixture ratio of Ar and nitrogen at the time of film formation.
2.1 silicon nitride layer.

After the formation of the protective film, 40
The disc is rotated while pressing the lapping tape of the 00 series with air pressure, and a tape cleaning (TC) process is performed to scrape off minute protrusions on the disc surface, and a low-pressure mercury lamp that generates wavelengths of 185 nm and 254 nm in the atmosphere is used for 90 seconds. After the irradiation treatment, a perfluoropolyether-based lubricant having a main chain of (F ((CF ₂ ) ₃ -O)) n and having a hydroxyl group at one end in a perfluorooctane solvent at a concentration of 0.0
By spin coating using a solution consisting of 2% by weight,
A lubricating layer was formed on the protective film.

The recording / reproducing characteristics of the optical recording media of Examples 23 to 34 were evaluated with the same measuring apparatus used in the defect evaluation of Examples 3 to 22. For evaluation, a relatively long mark having a linear velocity of 14 m / s and a mark length of 0.8 μm was recorded, and its carrier level and noise level were measured. Further, the reflection signal level at the groove was measured at the same time.

[0077]

[Table 5]

Example 35 A 3.5 inch-sized polycarbonate substrate having a dot texture of 35 nm in height and 1.5% in area in a 4 mm wide CSS zone on the inner periphery of the land, groove and disk was injection molded using a Ni stamper. Produced. 50n on this substrate
m AlTi reflective layer, 30 nm first SiNx layer (first dielectric layer),
20nm TbFeCo recording layer (magneto-optical recording layer), 80nm second SiNx
The layers (second dielectric layer) were sequentially sputtered.

Next, a 20 nm hydrogen-containing carbon protective film (diamond-like carbon) was formed on the second SiNx layer by a plasma CVD method using methane as a monomer gas and hydrogen as a carrier gas using a high frequency of 13.56 MHz. A film was formed.

Then, using perfluorooctane as a solvent, the main chain is (F ((CF ₂ ) ₃ -O)) _n on the protective film (where,
(n is an integer of 10 to 14) and a perfluoropolyether-based lubricant having an alcohol group at one end of the molecule was spin-coated at a concentration of 0.02 wt.% to produce a magneto-optical recording medium. On the optical head side, a methane gas is used as a monomer gas and a hydrogen gas is used as a carrier gas on the surface of a flying slider having a solid immersion lens magnetic field modulation coil in the same manner as shown in FIGS. Then, a hydrogen-containing diamond-like carbon protective film having a thickness of 10 nm was formed by a plasma CVD method.

Example 36 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(F ((CF ₂ ) ₃ -O)) _n (where n is an integer of 10 to 14) and a perfluoropolyether-based lubricant having a carboxyl group at one terminal of the molecule is used at a concentration of 0.02 wt. A magneto-optical recording medium was produced in the same manner as in Example 35 except that spin coating was carried out at%.

Example 37 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(F ((CF ₂ ) ₃ —O)) _n (where n is an integer of 10 to 14) and a perfluoropolyether-based lubricant having an ester group at one end of the molecule at a concentration of 0.02 wt. A magneto-optical recording medium was produced in the same manner as in Example 35 except that spin coating was carried out at%.

Example 38 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(F ((CF ₂ ) ₃ —O)) _n (where n is an integer of 10 to 14) and a perfluoropolyether-based lubricant having a piperonyl group at one terminal of the molecule is used at a concentration of 0.02 wt. A magneto-optical recording medium was produced in the same manner as in Example 35 except that spin coating was performed at a rate of 10%.

Example 39 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(-(CF ₂ ) ₂ -O) _n (CF ₂ -O) _m- ) (where n is 9 to 1)
3 and m is an integer of 9 to 13) and the same as Example 35 except that a perfluoropolyether-based lubricant having hydroxyl groups at both molecular ends was spin-coated at a concentration of 0.02 wt.%. Thus, a magneto-optical recording medium was manufactured.

Example 40 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(-(CF ₂ ) ₂ -O) _n (CF ₂ -O) _m- ) (where n is 9 to 1)
3 and m is an integer of 9 to 13) and the same as Example 35 except that a perfluoropolyether-based lubricant having a carboxyl group at both molecular terminals was spin-coated at a concentration of 0.02 wt.%. Thus, a magneto-optical recording medium was manufactured.

Example 41 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(-(CF ₂ ) ₂ -O) _n (CF ₂ -O) _m- ) (where n is 9 to 1)
3, and m is an integer of 9 to 13), and a perfluoropolyether-based lubricant having ester groups at both molecular ends is spin-coated at a concentration of 0.02 wt.%,
A magneto-optical recording medium was manufactured in the same manner as in Example 35.

Example 42 Using perfluorooctane as a solvent, a main chain was formed on the protective film.
(-(CF ₂ ) ₂ -O) _n (CF ₂ -O) _m- ) (where n is 9 to 1)
3 and m is an integer of 9 to 13) and the same as Example 35 except that a perfluoropolyether-based lubricant having a piperonyl group at both molecular terminals was spin-coated at a concentration of 0.02 wt.%. Thus, a magneto-optical recording medium was manufactured.

Example 43 The surface of the protective film was irradiated with a low-pressure mercury lamp emitting 185 nm and 254 nm wavelengths in the air for 90 seconds, and then the stearylamine (C ₁₈ H) was used on the protective film using methyl isobutyl ketone as a solvent. ₃₇ -NH ₂ ) and a partially fluorinated ester (C ₁₇ H ₃₁ COOC ₂ H ₄ C ₆ F ₁₃ ) which is liquid at room temperature, are each spin-coated at a concentration of 0.04 wt.%, And solid immersion is applied to the optical head side. Using a methane gas as the monomer gas and a hydrogen and nitrogen gas as the carrier gas, a 10 nm-thick hydrogen- and nitrogen-containing diamond-like carbon protective film is formed on the surface of the flying slider having a lens magnetic field modulation coil by plasma CVD. A magneto-optical recording medium was manufactured in the same manner as in Example 35 except for the above. As a result of measuring the composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating by X-ray photoelectron spectroscopy, the O / C ratio was 0.35.

Example 44 The surface of the protective film was subjected to plasma treatment in an atmosphere of oxygen pressure of 5 mTorr using a high frequency of 13.56 MHz. Thereafter, methyl isobutyl ketone was used as a solvent on the protective film to obtain stearylamine.
(C ₁₈ H ₃₇ -NH ₂ ) and partially fluorinated esters that are liquid at room temperature
A magneto-optical recording medium was produced in the same manner as in Example 43, except that (C ₁₇ H ₃₁ COOC ₂ H ₄ C ₆ F ₁₃ ) was spin-coated at a concentration of 0.04 wt.%, Respectively. The composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating was measured by X-ray photoelectron spectroscopy. As a result, the O / C ratio was 0.39.

Example 45 Using methyl isobutyl ketone as a solvent on a protective film,
N, N-dimethylstearial amine (C ₁₈ H ₃₇ -N (CH ₃ ) ₂ )
And a partially fluorinated ester that is liquid at room temperature (C ₁₇ H _{3 1} COOC ₂ H ₄
A magneto-optical recording medium was produced in the same manner as in Example 35, except that each of C ₆ F ₁₃ ) was spin-coated at a concentration of 0.04 wt.%. The composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating was measured by X-ray photoelectron spectroscopy
As a result, the O / C ratio was 0.35.

Example 46 Using methyl isobutyl ketone as a solvent on a protective film,
Stearylamine (C ₁₈ H ₃₇ -NH ₂ ) and partially fluorinated ester ((CF ₃ ) ₂ CF (CF ₂ ) ₁₀ CH ₂ CH [OCOC (CH ₃ ) ₂
(C ₆ H ₁₃ )] CH ₂ [OCOC (CH ₃ ) ₂ (C ₆ H ₁₃ )])
A magneto-optical recording medium was produced in the same manner as in Example 43 except that spin coating was performed at a concentration of t.%. As a result of measuring the composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating by X-ray photoelectron spectroscopy, the O / C ratio was 0.35.

Example 47 Using methyl isobutyl ketone as a solvent on a protective film,
Stearylamine (C ₁₈ H ₃₇ -NH ₂₎ and partially fluorinated ester is a liquid at room temperature _{((CF 3) 2 CF (} CF 2) 10 CH 2 CH (OCOC 17 H 31) CH
₂ (OCOC ₁₇ H ₃₁ )) was spin-coated at a concentration of 0.04 wt.%, Respectively, to produce a magneto-optical recording medium in the same manner as in Example 43. As a result of measuring the composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating by X-ray photoelectron spectroscopy, the O / C ratio was 0.35.

Example 48 Using methyl isobutyl ketone as a solvent on a protective film,
Stearylamine (C ₁₈ H ₃₇ -NH ₂ ) and a partially fluorinated ester ([(CH ₃ ) ₂ CH (CH ₃ ) CH] ₂ C (CH ₃ ) COOCH ₂ C ₆ F ₁₂
A magneto-optical recording medium was prepared in the same manner as in Example 43, except that each of CH ₂ COC (CH ₃ ) [(CH ₃ ) HCH (CH ₃ ) ₂ ] ₂ ) was spin-coated at a concentration of 0.04 wt.%. . As a result of measuring the composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating by X-ray photoelectron spectroscopy, the O / C ratio was 0.35.

Example 49 Using methyl isobutyl ketone as a solvent on a protective film,
Stearylamine (C ₁₈ H ₃₇ -NH ₂ ) and a partially fluorinated ester ([(CH ₃ ) ₂ CH (CH ₃ ) CH] ₂ C (CH ₃ ) COOCH ₂ C
_A magneto-optical recording medium was produced in the same manner as in Example 43 except that each of ₆ F ₁₃ ) was spin-coated at a concentration of 0.04 wt.%. The composition ratio of oxygen and carbon on the surface of the protective film before applying the lubricant by spin coating was measured by X-ray photoelectron spectroscopy. As a result, the O / C ratio was 0.35.

Example 50 Using methyl isobutyl ketone as a solvent on a protective film,
Stearylamine (C ₁₈ H ₃₇ -NH ₂ ) and CH which is liquid at room temperature
₃ (CH ₂ ) ₁₁₀ (CH ₂ ) ₃ NHCOCF ₂ (OC ₂ F ₄ ) ₁₀ (OCF ₂ ) ₁₀ CF ₂ CONH (C
A magneto-optical recording medium was produced in the same manner as in Example 43, except that H ₂ ) ₃₀ (CH ₂ ) ₁₁ CH ₃ was spin-coated at a concentration of 0.04 wt.%, Respectively. The composition ratio of oxygen and carbon on the surface of this protective film
As a result of measurement by X-ray photoelectron spectroscopy, the O / C ratio was 0.35.

Example 51 A magneto-optical recording medium was manufactured in the same manner as in Example 35, except that a flying type slider having a solid immersion lens having no protective film on the slider surface and a magnetic field modulation coil was manufactured.

Example 52 A magneto-optical recording medium was manufactured in the same manner as in Example 47, except that a flying type slider having a solid immersion lens having no protective film on the slider surface and a magnetic field modulation coil was manufactured.

Comparative Example 3 A 3.5 ″ size polycarbonate substrate having lands and grooves and no CSS zone was produced by an injection molding method using a Ni stamper. On this substrate, a 50 nm AlTi reflection layer was formed.
30 nm first SiNx layer, 20 nm TbFeCo recording layer, 80 nm second Si
Nx layers were sequentially sputtered. Thereafter, using perfluorooctane as a solvent, the main chain is (F ((CF ₂ ) ₃ -O)) _n on the protective film (where n is an integer of 10 to 14), and one end of the molecule is used. Was spin-coated with a perfluoropolyether lubricant having a hydroxyl group at a concentration of 0.02 wt.%.

As an optical head, a flying diamond slider having a solid immersion lens magnetic field modulation coil was coated on the surface of a diamond-like carbon protective film containing hydrogen with a thickness of 10 nm by a plasma CVD method using methane gas as a monomer gas and hydrogen gas as a carrier gas. A film was formed.

Comparative Example 4 A magneto-optical recording medium was produced in the same manner as in Comparative Example 3, except that a flying type slider having a solid immersion lens having no protective film on the slider surface and a magnetic field modulation coil was produced.

The durability of the sample obtained above was measured using Lotus CSS
Using a Tester Model 7000, a CSS test was performed under the following conditions. Table 6 shows the CSS test results. Disk rotation speed: 3600 rpm, measurement radius: 22 mm Relative speed: 8.29 m / sec Head flying height: 60 nm Head vertical load: 3.5 g Measurement environment: 20 ° C., 40% RH

[0102]

[Table 6]

As is clear from Table 6, in the system of the combination of the medium of the present invention and the flying type slider having a protective film on the slider surface, the coefficient of static friction is less than 0.60 and the CSS resistance is lower.
The durability is more than 20,000 cycles. Further, in the system of the present invention in which the medium and the flying type slider having no protective film on the slider surface have a static friction coefficient exceeding 0.60, the CSS
Durability is over 20,000 cycles. On the other hand, the system of the combination of the medium of Comparative Example 3 having no dot texture and the protective film on the medium and the flying slider having the protective film on the slider surface, and the Comparative Example 3 having no dot texture and the protective film on the medium were used. The combination of the medium and the flying slider without the protective film on the slider surface (Comparative Example 4) has a high coefficient of static friction of 5.0 or more and a CSS durability of less than 1,000.
It turns out that it is inferior in durability.

The optical recording medium, the optical head, and the optical recording apparatus of the present invention have been specifically described above by taking the case of recording and reproducing on a magneto-optical recording medium as an example. The optical recording medium is not limited to a magnetic recording medium, and may be any optical recording medium such as a phase-change optical recording medium, a write-once optical recording medium having an organic dye in a recording layer, or a read-only optical recording medium. That is, the optical recording medium to which the present invention is applied is a solid protective layer having a self-lubricating property on the uppermost layer of the optical recording medium on which light is irradiated, in an optical recording medium on which information is recorded or reproduced by light irradiation. Is formed on the optical recording medium. Ordinary optical recording media have a structure in which a recording layer is provided directly on a substrate via a protective layer or the like, and recording or reproduction light is irradiated from the substrate side. In an optical recording medium according to the present invention, the optical recording medium is opposite to the substrate. A solid protective layer having self-lubricating properties is formed on the uppermost layer on the side, and light from the recording or reproducing layer is irradiated from the side of the solid protective layer.

In the above embodiment, an optical head for recording / reproducing a magneto-optical recording medium has been described as an example of the optical head. However, the configuration of the optical head is not limited to the structure shown in FIG. A structure may be employed. For example, a phase-change optical recording medium, a write-once optical recording medium containing a dye in a recording layer, and C
D, When recording or reproducing data on a DVD-ROM, a magnetic coil is not required as a magnetic field applying means.

[0106]

According to the present invention, a self-lubricating protective film such as carbon is provided on at least one of the optical recording medium and the surface of the optical head facing the optical recording medium, so that the optical head seeks. It is possible to suppress the occurrence of scratches caused by the irregular sliding of the head and the medium due to the change in the attitude of the head due to the movement of the head, and to reduce the reproduction error caused by the occurrence of the scratches. In addition, instead of the protective film having self-lubricating property or together with the protective film having self-lubricating property, a molecular weight selected from at least one of a hydroxyl group, a carboxyl group, an ester group, an amino group, and a piperonyl group at a molecular terminal is from 1,000 to 8,000. By using a lubricant containing perfluoropolyether, the occurrence of scratches on the optical recording medium can be suppressed, and reproduction errors caused by the occurrence of scratches can be reduced. Therefore, an optical recording device incorporating the optical head of the present invention is suitable for high-density recording on an optical recording medium and reproduction thereof.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a state where a laser beam is narrowed down by a lens.

2A and 2B are diagrams illustrating an optical path when a solid immersion lens is used, wherein FIG. 2A illustrates a hemispherical solid immersion lens, and FIG. 2B illustrates a super-hemispherical solid immersion lens.

FIG. 3 is a schematic sectional view illustrating the structure of a slider type optical head used in a recording / reproducing method using a solid immersion lens and near-field light.

FIG. 4 is a schematic cross section of a specific example of the optical recording medium of the present invention.

FIG. 5 is a schematic sectional view of a magneto-optical head manufactured in Example 2 of the present invention.

FIG. 6 is a diagram showing a concavo-convex pattern formed on the bottom surface of a slider of the optical head manufactured in Example 2.

FIG. 7 is a diagram showing a schematic structure of an optical recording device of the present invention.

FIG. 8 is an enlarged view of a structure of an objective lens portion of the optical recording device of FIG.

FIG. 9 is a diagram illustrating an optical system used in the optical recording device according to the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 hemispheric solid immersion lens, 2 super hemispheric solid immersion lens 3 laser light, 4 optical recording medium, 33, 69 mirror 34, 71 objective lens, 35, 36 swing arm 37 rotary actuator, 38 optical system 39 disk rotation axis, Reference Signs List 40 motor 41 magneto-optical disk, 43 objective lens support 44 actuator coil, 45 permanent magnet for actuator 46 laser light, 57 laser light source 59a, b prism, 60, 61, 64 beam splitter 63 1 / 2λ plate, 68a, b light Magnetic signal detector 69, 70 Mirror, 80 Slider bottom 71 Objective lens, 72, 100 Solid immersion lens 102 Slider, 104 Magnetic coil, 105 Protective film

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification code FI G11B 11/10 521 G11B 11/10 521E 521F 566 566B (72) Inventor Tatsuo Araki 1-1-88 Ushitora 1-chome, Uchitora, Ibaraki-shi, Osaka Hitachi Inside Maxell Co., Ltd. (72) Inventor Takeshi Takeshi 1-88 Usutora, Ibaraki-shi, Osaka Inside Hitachi Maxell Co., Ltd.

Claims (34)

[Claims] 1. An optical recording medium having a reflective layer, a recording layer, and a dielectric layer on a substrate and irradiated with recording light or reproduction light from the dielectric side, wherein the dielectric layer has a self-lubricating property. An optical recording medium comprising a solid protective layer formed thereon. 2. The solid protective layer having self-lubricating properties,
Have an extinction coefficient with an absolute value of difference within 0.5 with respect to the refractive index of the dielectric layer and an extinction coefficient with an absolute value of within 0.2 with respect to the extinction coefficient of the dielectric layer. The optical recording medium according to claim 1, wherein: 3. The optical recording medium according to claim 1, wherein the thickness of the self-lubricating solid protective layer is 5 nm to 50 nm. 4. The solid protective layer having self-lubricating properties,
The optical recording medium according to any one of claims 1 to 3, wherein the optical recording medium is made of a material mainly composed of carbon. 5. The self-lubricating solid protective layer made of a material mainly composed of carbon, comprising at least one selected from the group consisting of nitrogen, hydrogen and fluorine. An optical recording medium according to claim 1. 6. The solid protective layer having self-lubricating properties,
The optical recording medium according to claim 1, wherein the optical recording medium is a diamond-like carbon film. 7. The optical recording medium according to claim 1, wherein a lubricating layer is further formed on the self-lubricating solid protective layer. 8. The lubricating layer has a group selected from at least one of a hydroxyl group, a carboxyl group, an ester group, an amino group and a piperonyl group at at least one of molecular terminals and has a molecular weight of 1,000 to 8,000. The optical recording medium according to claim 7, comprising a fluoropolyether. 9. The light according to claim 7, wherein the lubricating layer is formed of a mixed lubricant containing a lubricant having an amide group at a molecular end and a lubricant that is liquid at normal temperature. recoding media. 10. The optical recording medium according to claim 9, wherein said solid protective layer having self-lubricating properties has a carboxyl group on its surface. 11. The optical recording medium according to claim 10, wherein the composition ratio of oxygen / carbon (O / C) on the surface of the self-lubricating solid protective layer is 0.1 or more. 12. The method according to claim 7, wherein the lubricant is heat-treated at a temperature of 50 to 120 ° C. after being applied on the solid protective layer having a self-lubricating property. Optical recording medium. 13. The optical recording medium according to claim 7, wherein the lubricant is irradiated with ultraviolet light after being applied on the solid protective layer. 14. A carboxyl group is formed on the surface of the solid protective layer by irradiating the solid protective layer with self-lubricating properties with ultraviolet rays or by performing a plasma treatment in an oxygen atmosphere. 14. The optical recording medium according to any one of 13. 15. The optical recording medium according to claim 1, wherein the self-lubricating solid protective layer is formed by one of sputtering and plasma CVD. 16. The optical recording medium according to claim 1, wherein a landing zone of a flying slider is provided on an inner peripheral portion or an outer peripheral portion of the optical recording medium. 17. A height 10 within said landing zone.
17. The optical recording medium according to claim 16, wherein the optical recording medium has dot-shaped protrusions of 100 nm to 100 nm in an area ratio of 0.1% to 5.0%. 18. The optical recording medium according to claim 1, which is one of a magneto-optical recording medium and a phase change optical recording medium. 19. The optical recording medium according to claim 1, further comprising a dielectric layer between the reflection layer and the recording layer. 20. An optical recording medium having a reflective layer, a recording layer, a dielectric layer, a protective layer and a lubricating layer on a substrate, wherein recording light or reproducing light is irradiated from the lubricating layer side, The layer has a group selected from at least one of a hydroxyl group, a carboxyl group, an ester group, an amino group and a piperonyl group at at least one end of molecular ends, and contains a perfluoropolyether having a molecular weight of 1,000 to 8,000. An optical recording medium characterized by the following. 21. The optical recording medium according to claim 20, further comprising a dielectric layer between the reflection layer and the recording layer. 22. An optical head for mounting a solid immersion lens in a floating slider and recording or reproducing an optical recording medium, wherein at least a surface of the floating slider facing the optical recording medium has a self-lubricating property. An optical head, comprising a solid protective layer having the same. 23. The optical head according to claim 22, wherein the thickness of the self-lubricating solid protective layer is 5 nm to 50 nm. 24. The optical head according to claim 22, wherein the self-lubricating solid protective layer is made of a material mainly composed of carbon. 25. The self-lubricating solid protective layer composed of a material mainly composed of carbon, comprising at least one selected from the group consisting of nitrogen, hydrogen and fluorine. An optical head according to claim 1. 26. The optical head according to claim 22, wherein the solid protective layer having self-lubricating properties is a diamond-like carbon film. 27. The optical head according to claim 22, wherein a lubricating layer is further formed on the self-lubricating solid protective layer. 28. The lubricating layer has a group selected from at least one of a hydroxyl group, a carboxyl group, an ester group, an amino group and a piperonyl group at at least one of molecular terminals, and has a molecular weight of 1,000 to 8,000. 3. The composition according to claim 2, wherein said composition contains a fluoropolyether.
8. The optical head according to 7. 29. The light according to claim 28, wherein the solid protective layer has a carboxyl group on the surface and has a composition ratio of oxygen / carbon (O / C) of 0.1 or more. head. 30. The optical head according to claim 22, further comprising a magnetic coil for applying a recording or reproducing magnetic field. 31. An optical recording apparatus for recording or reproducing information on or from an optical recording medium, comprising an optical head, wherein the optical head has a floating slider and a solid immersion lens mounted on the floating slider. An optical recording device comprising a self-lubricating solid protective layer formed on at least a surface of the flying slider facing the optical recording medium. 32. The optical recording apparatus according to claim 31, wherein said optical head includes a magnetic field applying device, and is capable of recording and reproducing on a magneto-optical recording medium. 33. The solid immersion lens according to claim 31, wherein the solid immersion lens is one of a hemispherical solid immersion lens and a super hemispherical solid immersion lens.
33. The optical recording device according to 32. 34. The optical recording medium has a reflective layer, a first dielectric layer, a recording layer, and a second dielectric layer in this order on a substrate, and is irradiated with information recording or reproducing light from the second dielectric side. 34. The optical recording medium according to claim 31, wherein a solid protective layer having a self-lubricating property is formed on the second dielectric layer. The optical recording device as described in the above.