JP2003067993A - Information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a replaceable information recording medium which can be manufactured at a low cost, and has a large storage capacity and is able to stabilize the head run even when it is disposed close to the poles on a recording medium. SOLUTION: This magneto-optical disk 10 consists of a base plate 14, which is a flexible disk consisting of a macromolecule. On this plate, following layers and films are laminate in order: a base layer 15 to improve the recording property of a recording film, a magnetic recording layer 16 consisting of rare-earth element transition metal alloys to magnetically record information, a protection layer 18 to keep the magnetic recording layer 16 from degrading or wearing, and a lubrication film 20 to improve the run durability and corrosion resistance by applying lubricant.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium.
In particular, a replaceable information recording medium capable of high-density recording
Related. In recent years, DVD (Digital Versatile)
Le disk)-High capacity rewriting such as RW / RAM
Type optical disk, 1.3GB (gigabyte) magneto-optical disk
High capacity magneto-optical disk such as GIGAMO, Zip
Large capacity represented by high capacity flexible disks such as
And a high-speed data transfer medium
It is eyed. These large-capacity and replaceable information recording media
Is more than 100MB (megabyte) per disc
Storage capacity, and traditionally a personal computer
Not only the data handled by the data but also the high quality
Music information and video information can be recorded. For example,
The recording capacity of the above DVD-RW is 4.7 GB.
Video information of about 2 hours with video quality close to the current TV video
Can be recorded. Also incorporated into the recording system
In this case, the medium can be replaced because it is a replaceable medium.
Unlike the built-in hard disk, the capacity is limited.
Virtually nonexistent. In addition, even if the device is replaced
Can be stored permanently, making it suitable for archival storage
It has the feature of being. A recording system using a magnetic disk is a recording system.
Recording system such as recording density, access speed, transfer speed
As the highest performance, personal computer
It is attracting a great deal of attention, including development for other uses.
It is a recording system. Hard disks are used as magnetic disks.
The most common type of disk device is a flexible disk.
Both the recording device and the recording medium are inexpensive and
High reliability for impact and dust contamination during operation
There is a point. This varies from 1MB to several hundred MB
Flexible disks with large capacity are widely used
The For use with rewritable optical discs such as CD-R
The recording system was highly reliable and the media price was low.
Is the most popular recording system at present.
The More recently than CD-R (650MB per disc)
DVD-R (4.7 GB per disc) with high recording density
It started to spread. In addition, a recording system using a magneto-optical disk is used.
Are also common in the personal computer market.
It is accepted as a recording system. Currently, long-time recording and high-definition television projection
2 per disc to allow image recording
A storage capacity of 0 GB or more is required.
Disk, magneto-optical disk, magnetic disk,
Information recording for higher density and higher capacity
Research and development of devices and recording media are actively conducted
The As described above, the magnetic device
Disk, optical disk, and magneto-optical disk
And the expected increase in the amount of digital data
Various research and development are underway, but each recording system has its own
Have unique technical challenges. Increased recording density for hard disks
When increasing the size, the “thermal fluctuation” caused by the thermal stability of the magnetic particles
Although the problem of “Ragi” has been pointed out, high magnetic anisotropy
Perpendicular magnetic recording media using magnetic materials
Diamagnetic coupling type in-plane magnetism utilizing magnetic particle interaction
A new magnetic recording method using recording media has been proposed.
In the future, the recording density of hard disks will continue to increase.
300GB recording per 3.5 inch disk
It is considered possible. However, the hard disk device is replaceable.
In addition, many mechanical parts are built in the recording device.
Therefore, it cannot be used for archival storage of information.
The hard disk media is stored in the cartridge.
And use it like a flexible disk.
Removable hard disks are also commercialized
However, if the reliability against impact during operation or dust contamination is low,
There is such a problem. This system also has a disk
Includes magnetic disks used in hard disk drives.
Precision surface of glass, quartz, aluminum, etc.
Because the processed substrate is used, the media price is
It is very expensive compared to a flexible disk
There is a problem. On the other hand, the current flexible disk is
The recording film has a commutability not found in hard disks.
Disperses fine iron powder, inorganic fine particles, and lubricant in polymer resin
Recording characteristics due to the so-called coating-type medium.
Disk recording density is low compared to disk and hard disk
Yes. In addition, for the support, polyethylene terephthalate, etc.
Because of the use of flexible polymer film
The surface shake (RO, NRRO) is large and the track pitch
Can not narrow the h For these reasons, the current
Future information volume will increase on existing flexible disks
That the storage capacity is not enough to handle
There was a title. Surface recording density of optical disk and magneto-optical disk
The main method for improving
A so-called blue-purple semiconductor laser with a wavelength of about 400 nm
How to make recording marks smaller by using color laser
The numerical aperture of the objective lens used for laser focusing
How to reduce the size of the recording mark.
It is. In fact, using these methods, you can record over 20GB.
Many research examples of creating optical disks with storage capacity have been reported
Has been. However, the above method alone
It is very difficult to increase the capacity of
Do not use new methods that are not available in recording and magneto-optical recording methods.
I have to. As a next generation high density recording system, Ebane
Recording method using scent light (near-field optical recording, air
(Also called field recording) and signal recording with laser light and magnetism.
And GMR (Giant
Magneto Resistive head and TMR (Tunnel Magneto)
Resistive) Has a hybrid magneto-optical recording performed by the head
It is being devised. With these recording methods, the CD size
To obtain a storage capacity of 100 GB or more per disc
It is expected to be able to. Evanescent light has a small aperture below the wavelength.
Occurs when light scatters or diffracts in the vicinity of a small aperture
(Within the region below the wavelength of the light from the exit end of the minute aperture)
It is localized non-propagating light. Solid immersion lenses (SI
L: Solid Immersion Lens)
Even evanescent light can be generated. This
By performing optical recording using evanescent light of
Recording marks smaller than those recorded by normal optical recording
This makes it possible to reduce the surface recording density of information.
It is expected to be able to increase significantly. On the other hand, the evanescent light is connected to the head.
The area below the wavelength of light from the small aperture or SIL exit end
In the near-field optical recording method, recording
A magnetic recording layer is formed near the surface of the medium and the head
Near the recording medium (specifically, within a range of several tens of nm)
Recording and playback must be performed.
Yes. In the hybrid magneto-optical recording system,
Using a normal magneto-optical recording medium, the head track width
Do not heat the magnetic recording layer by irradiating a laser beam with a narrow width.
Recording with a magnetic head and a GMR head
Using a high-sensitivity magnetic head, such as a TMR head
Compared with optical reproduction, line drawing is performed.
Recording density can be improved. In the hybrid magneto-optical recording system, line recording is performed.
When recording to a hard disk to increase the density
Reduce the distance between the head and the magnetic recording layer
It is necessary to perform magnetic field modulation recording by magnetic field reversal. others
Therefore, even in the hybrid magneto-optical recording system, the surface of the recording medium
A magnetic recording layer is formed in the vicinity and the head is connected to a recording medium.
Recording and playback must be performed in the immediate vicinity of
Absent. The next generation optical recording system and magneto-optical recording described above
The method is the same as when recording to a hard disk, for example.
In addition, a magnetic recording layer on a mirror-polished ultra-smooth glass substrate
Combination of recording medium with flying head and flying head
There is an attempt to realize it by using it. However, conventionally, an audible optical disk
For plastics such as polycarbonate, the thickness is about 1.2 mm.
Sticky substrates are used, but plastic substrates are
Since the flatness is poor compared to the glass substrate, the head and the
Contact with the disc is likely to occur, and at the time of contact, the elastic modulus of the substrate
The failure of the board to deform, etc.
There is a problem. Especially for audible media, the head and disc
Due to dust trapped between the
Or the disk is likely to be damaged.
The If a glass substrate is used as the substrate,
Compared to the case of using a plastic substrate,
The cost of the strikes and servolights increases, making the product expensive
There was a problem that it would be worth it. Furthermore, in the conventional optical disk, polycarbonate is used.
Grooves and irregularities are formed in advance on the surface of the substrate,
A servo system that performs tracking as a signal is used.
However, this method has large irregularities on the disk surface.
It will be. For this reason, the head is placed very close to the recording medium.
Need to use a flying head
In the next generation high-density recording system, damage to devices and media
It is difficult to achieve a stable head running state without
There is a problem. On the other hand, like a hard disk
In the method of writing servo signals directly with the head, the servo
It is difficult to increase the rotation speed at the time
Because of this, servo writing takes time and manufacturing costs are high.
Become. The present invention has been made in view of the above problems of the prior art.
The object of the present invention is to provide a head for a recording medium.
Stable head travel is possible even when placed close to the pole
Provides audible information recording media capable of high-density recording
There is to do. Another object of the present invention is to manufacture at a low cost.
To provide an audible information recording medium that can be manufactured
It is in. In order to achieve the above object,
In addition, the information recording medium of the present invention is a flexible polymer support.
On at least one surface of the flexible polymer support.
Perpendicular magneto-optical recording layer made of a rare earth transition metal alloy
It is characterized by including. The information recording medium of the present invention is used as its support.
By using a flexible polymer support,
Impact is avoided when the disc comes into contact with the flying
Like the next-generation high-density recording system that uses a head,
Even when the disk is placed very close to the recording medium, the head and the
Stable contact and sliding with the disc allows stable head running
It becomes ability. Also, a flexible polymer is used as the base material.
Therefore, it can be manufactured at low cost. Furthermore, rare earth transition
Because it has a magnetic recording layer made of a transfer metal alloy,
Perpendicular magnetic recording using a head placed very close to the medium.
Alternatively, high density recording is possible by magneto-optical recording. In the above information recording medium, the head and the
In order to prevent damage due to contact with the disk more effectively
Furthermore, the thickness of the flexible polymer support is 10 μm to 200 μm.
m is preferable. Also constitutes a magnetic recording layer
Rare earth transition metal alloys are terbium (Tb), gadolini
Um (Gd), Neodymium (Nd), and Dysprosiu
At least one rare earth metal selected from (Dy)
And at least one of iron (Fe) and cobalt (Co)
It is preferable to contain these transition metals. Such magnetic
Since the air recording layer can be produced by sputtering at room temperature,
Common Co alloys currently used in hard disks
Compared to the recording layer, there is less heat damage to the support and
This can be reduced. In the above information recording medium, the magnetic recording layer
Is pre-concentric with the center of the disk for tracking
Magnetized in a circular or spiral shape and the magnetization direction
So that magnetized regions with different diameters are arranged alternately in the radial direction
It is preferably magnetized. Magnetization regions having different magnetization directions in advance in the magnetic recording layer
To magnetize so that the regions are arranged alternately in the radial direction
For example, the magnetization of the magnetization region using the Kerr rotation angle of light
Tracking based on direction differences
The Also, the magnetic recording layer is concentric with the center of the disk in advance.
Track or magnet by spiraling
Tracking can be performed continuously and accurate tracking and
Servo can be performed. Furthermore, the magnetization direction of the magnetization region
Since the tracking is based on the difference between
It is not necessary to form irregularities on the smooth substrate of
Stable head running even when placed very close to the recording medium
A row state can be realized. In this case, the magnetization direction for tracking
Is perpendicular to the disk surface and the magnetization direction of the disk
By being perpendicular to the surface, they are alternately arranged in the radial direction.
Magnetized regions with different magnetization directions are mutually aligned with their magnetic force.
The magnetic force of each magnetization region is stabilized.
To do. The magnetic recording layer also has a flexible polymer support.
On at least one side of the body with an underlayer
Even if a protective layer is provided on the magnetic recording layer,
Good. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
The embodiment will be described in detail. Magneto-optical disk 10 according to the present embodiment
As shown in FIG. 1 (A), the center ho
So-called flexible disk
Inside the cartridge 12 made of plastic or the like.
Stored. The cartridge 12 usually has
Access window covered with a metallic shutter (not shown)
(Not shown) and light through this access window
Recording and reproduction on the magnetic disk 10 are performed. The magneto-optical disk 10 is shown in FIG.
Thus, a disk-shaped support 1 made of a flexible polymer
4 on the underlayer for controlling the magnetic characteristics of the magnetic recording layer
15. Magnetic recording layer 16 for magnetically recording information, magnetic recording
A protective layer 18 that protects the recording layer 16 from deterioration and wear;
A lubricant that improves running durability and corrosion resistance by the addition of a lubricant.
The synovial membrane 20 is configured by being laminated in this order. Na
As will be described later, between the support 14 and the underlayer 15,
Reflective layer and dielectric to control heat conduction and heat diffusion rate
A layer may be provided. The magnetic recording layer 16 is perpendicular to the disk surface.
Has direct magnetic anisotropy and magneto-optic effect
Thus, perpendicular magneto-optical recording of information is possible. Also magnetic
The recording layer 16 is magnetically perpendicular to the tracking information.
(Preformat magnetization) and the support 14
If the opposite surface is the recording surface, the support side should be
Magnetized region 16A magnetized in the direction in which the recording surface side becomes the north pole
And magnetization in the direction where the support side is N pole and the recording surface side is S pole.
And the magnetized region 16B. This
These magnetized area 16A and magnetized area 16B are formed in the disc half.
They are arranged alternately in the radial direction. FIG. 1B shows a region A in FIG.
FIG. 1 shows the magnetization state of the recording surface of the magnetic recording layer 16.
As shown in (B), the magnetized region 16A and the magnetized region 16
Each B is concentric or spy with respect to the disc center
Each of them forms a track, and each constitutes a track. Immediately
That is, the magnetization region 16A and the magnetization region 16B have a magnetization method.
Used as a tracking guide
And used as a recording area. This magneto-optical display
In the disk 10, laser light is applied from the magnetic recording layer 16 side.
Is recorded and information is recorded and reproduced. In the present embodiment, the magnetic recording layer 16
Is magnetized vertically according to the tracking information
The example has been described, but tracking information can be
Information may be recorded. In addition, as shown in FIG.
And the magnetized region 16B meanders at a constant frequency (wob
May be formed). This wobble meander
Used as a control signal to detect the frequency and control the linear velocity
Can be used. For example, the same circumference from the inner circumference to the outer circumference
By inserting the wobbles of the period, the line is regardless of the radial position
The speed can be controlled to be constant. Also,
Wobble so that the period becomes longer from the inner circumference to the outer circumference
By controlling, the angular velocity is controlled to be constant
be able to. The support 14 is in contact with the head and the disk.
Resin with flexibility to mitigate impact
It is composed of a film (a flexible polymer support).
As such a resin film, aromatic polyimide,
Aromatic polyamide, aromatic polyamideimide, polyether
Telketones, polyethersulfones, polyethers
Mido, polysulfone, polyphenylene sulfide,
Polyethylene naphthalate, polyethylene terephthalate
Polycarbonate, triacetate cellulose,
Examples thereof include a resin film made of a fluorine resin or the like. In addition, the same resin film or the like is applied to the support 14.
Alternatively, other resin films may be laminated.
Yes. By laminating other resin films,
Can reduce warping and undulation caused by the body itself
The This reduces surface shake when the disc is rotating.
The collision frequency and collision strength between the head and disk
To significantly improve the scratch resistance of the magnetic recording layer
I'm going. In addition, a magnetic recording layer was formed on one side during manufacturing.
Since it can be handled in a state, magnetic recording on both sides of the support
The film is harder to scratch than the recording layer
Defects caused by meandering are less likely to occur. As a laminating method, a heat roller is used.
Roll laminating, laminating by flat plate heat press, etc.
Can be used. Adhesive application methods include contact
A method of laminating by applying an adhesive on the contact surface, release in advance
A method using an adhesive sheet in which an adhesive is applied on paper
Can be mentioned. The type of adhesive is not particularly limited and is generally
Hot melt adhesives, thermosetting adhesives, UV curable adhesives
Adhesive, EB curable adhesive, pressure sensitive adhesive sheet, anaerobic adhesive
You can use it. The thickness of the support 14 is 10 μm to 200 μm.
m, preferably 20 μm to 150 μm, more preferably
Is 25 μm to 80 μm. The thickness of the support 14 is reduced
If it is too close, the stability at high speed decreases and the surface blur increases.
The On the other hand, if the thickness of the support 14 is too thick, the rigidity during rotation
And it becomes difficult to avoid impacts at the time of contact.
This causes the head to jump. The waist strength of the support 14 represented by the following formula:
The value at b = 10 mm is 0.5 kgf / mm ² ~ 2.
0kgf / mm ² Is preferably in the range of 0.7,
kgf / mm ² ~ 1.5kgf / mm ² Is more preferable. Support waist strength = Ebd ^Three / 12 In this equation, E is Young's modulus, and b is film.
Width and d each represent film thickness. The surface of the support 14 is recorded with a magnetic head.
It is preferable to be as smooth as possible for recording.
Yes. The irregularities on the surface of the support 14 show the signal recording / reproduction characteristics.
Reduce it. Specifically, the undercoat layer described later is used
The surface roughness measured with an optical surface roughness meter.
Is within 5 nm, preferably 2 nm in average centerline roughness Ra
The protrusion height measured with a stylus roughness meter is within 1 μm,
Preferably, it is within 0.1 μm. Also, use an undercoat film
If not, surface roughness measured with an optical surface roughness meter
Has an average centerline roughness Ra within 3 nm, preferably 1 n
m, the height of the protrusion measured with a stylus roughness meter is 0.1 μm
Within 0.06 μm, preferably within 0.06 μm. Support surface on the side where the magnetic recording layer 16 is provided
An undercoat layer should be provided on the surface to improve flatness.
And are preferred. The magnetic recording layer 16 is formed by sputtering or the like.
Therefore, it is preferable that the undercoat layer has excellent heat resistance.
In addition, as a material for the undercoat layer, for example, polyimide resin
Fat, polyamide imide resin, silicone resin, fluorine resin
Fats and the like can be used. Thermosetting polyimide tree
Fat, thermosetting silicone resin has a high smoothing effect, especially
preferable. The thickness of the undercoat layer is 0.1 μm to 3.0 μm
Is preferred. Laminate other resin film on support 14
If you want to apply an undercoat layer before laminating,
It is possible to form an undercoat layer after laminating.
Yes. Examples of thermosetting polyimide resins include
For example, bisallyl nadiimide "BAN" manufactured by Maruzen Petrochemical Co., Ltd.
I ”has two or more terminal unsaturated groups in the molecule
Polyimide resin obtained by thermal polymerization of imide monomer
Are preferably used. This imide monomer is a monomer
After coating on the support surface in the state of
Supports the monomer used as a raw material
It can be applied directly on the body and cured. Also this
The imide monomer can use a general-purpose solvent,
It has excellent productivity and workability, and has a low molecular weight.
Due to low solution viscosity, wrap around irregularities during application
And smoothing effect is high. As the thermosetting silicone resin, an organic group is used.
Polymerized by the sol-gel method using the introduced silicon compound as a raw material
The silicon resin used is preferably used. This silicon tree
Fat has a structure in which part of the bond of silicon dioxide is replaced with an organic group.
Made from a structure that has significantly better heat resistance than silicon rubber
Both are more flexible than silicon dioxide films, so
Even if a resin film is formed on a support made of a flexible film,
Cracks and peeling are unlikely to occur. Monomer used as raw material
Can be applied directly on the support and cured.
General-purpose solvent can be used,
The smoothing effect is high. Furthermore, the condensation polymerization reaction is
From relatively low temperatures by adding catalysts such as acids and chelating agents
Because it progresses, it can be cured in a short time,
A resin film can be formed using a coating apparatus. On the surface of the undercoat layer, there are a head and a disk.
Reduce the true contact area and improve the sliding characteristics
As a target, it is preferable to provide a minute protrusion. Also fine
By providing small protrusions, the handling of the support is also possible
Become good. As a method of forming the microprojections, a spherical
Method of applying Rica particles, applying emulsion and organic
The method of forming protrusions of objects can be used, but the undercoat layer
In order to ensure the heat resistance of the
It is preferable to form small protrusions. The height of the fine protrusion is preferably 5 nm to 60 nm.
Further, 10 nm to 30 mm is more preferable. Microprojections
If the height is too high, the spacing between the recording / reproducing head and the medium
Loss causes signal recording / reproduction characteristics to deteriorate, and microprotrusions
If it is too low, the effect of improving the sliding characteristics is reduced. Microprotrusions
The density of 0.1-100 pieces / μm ² Is preferred, 1-1
0 / μm ² Is more preferable. The density of microprojections is low
If it is too tight, the effect of improving the sliding characteristics is reduced and too much
Recording and playback with increased protrusions due to increased aggregated particles
Characteristics deteriorate. Also, a microprojection is supported using a binder.
It can also be fixed on the body surface. Enough for binder
It is preferable to use a resin with excellent heat resistance.
Examples of the resin having the property include thermosetting polyimide resin, heat
It is particularly preferable to use a curable silicone resin. Between the support 14 and the magnetic recording layer 16,
Read signal and tracking accuracy by light
In order to enhance, like a general magneto-optical disk, the reflective film
Can be provided. The reflective film is against the laser beam.
A light reflective material with high reflectivity is used. Such light
Examples of the reflective material include Al, Al—Ti, Al—
In, Al-Nb, Al-Ta, Au, Ag, Cu, etc.
Mention may be made of metals and metalloids. These substances are
It can be used alone or in combination of two or more.
Yes. Moreover, you may use as an alloy. This reflective film is
Sputtering the light reflecting material onto the support 14, or
Can be formed by electron beam vacuum deposition.
Yes. The thickness of the reflective film is preferably 10nm to 200nm
Yes. The recording characteristics and corrosion resistance of the magnetic recording layer 16 are improved.
For the purpose of good, it is placed between the support 14 and the magnetic recording layer 16.
The formation 15 is preferably provided. Used for magnetic recording layer
Rare earth transition metal alloys are generally amorphous vertical
Magnetic recording film and magnetic interaction in the recording film
Very strong. Magneto-optical disks are heated and maintained by laser light.
It is recorded with weak magnetic force and interaction, but
Write tracking signal by copying method and some signals
When trying to record with a magnetic head, rare earth transition
A magnetic recording layer made of a metal alloy alone does not have a domain wall motion mode.
It is easy to record and causes problems such as poor magnetization reversal and high noise.
Wake up. For this reason, the surface layer 15 has an appropriate surface roughness and bonding.
By providing a crystal structure, the magnetic domain in the magnetic recording layer
Can be easily generated, and the spin inversion mode
Magnetic recording can be used. For the underlayer 15, for example, titanium or aluminum
Metals such as nium, chromium, nickel, or these
Alloys of metals with other metals, phosphorus compounds such as nickel phosphide
And carbon such as graphite and amorphous carbon
It is done. In addition, the dielectric material described later can be used.
Yes. The underlayer 15 is formed by sputtering, vacuum deposition, CVD
It can be created by the so-called vacuum film formation method such as
Appropriate surface roughness and crystal structure can be adjusted by adjusting film conditions and film thickness.
It is necessary to grant structure. The surface roughness is Rmax
5 to 20 nm, and the particle size is about 1 to 30 nm.
preferable. The film thickness is preferably 10 nm to 200 nm. A dielectric is provided between the support 14 and the underlayer 15.
A layer may be provided. The dielectric layer is used during laser irradiation and laser
The temperature of the magnetic recording layer 16 after the irradiation is controlled and water
Involved in corrosion and oxidation of the magnetic recording layer 16 such as oxygen and oxygen
Shields substances from moving from the support side. Dielectric
The layer is made of a dielectric material commonly used in magneto-optical recording.
Can be used. Examples of the dielectric material include silica and aluminum.
Oxides such as Lumina (Si-O, Al-O), silicon nitride
Nitrides such as silicon and aluminum nitride (Si-N, Al-
N), sulfides such as zinc sulfide (Zn-S), nickel phosphide
Phosphides such as tantalum, tantalum silicide (Ta-Si),
Examples include carbon such as lafite and amorphous carbon.
Is a metal material that has corrosion resistance and is included in the magnetic recording layer.
Material that suppresses reaction with oxygen and has high thermal conductivity
Are preferred, silicon nitride (Si-N), aluminum nitride
Inorganic nitrides such as um (Al-N) and carbon are particularly preferred
That's right. This dielectric layer is formed by sputtering or chemical vapor reaction.
It can be formed by a method (CVD method) or the like. Invitation
The thickness of the electric layer is preferably 10 nm to 200 nm. For the underlayer 15, for example, titanium or aluminum
Metals such as nium, chromium, nickel, or these
Alloys of metals with other metals, phosphorus compounds such as nickel phosphide
And carbon such as graphite and amorphous carbon
It is done. The above dielectric materials can also be used.
The These underlayers are formed by sputtering, vacuum deposition, CV
It can be created by a so-called vacuum film formation method such as the D method.
Appropriate surface roughness and crystal by adjusting film forming conditions and film thickness
It is necessary to give structure. Rmax as surface roughness
5 to 20 nm, particle size of about 1 to 30 nm
Is preferred. The film thickness is preferably 10 nm to 200 nm. The magnetic recording layer 16 has a magnetic recording material.
Use amorphous rare earth transition metal alloys
The Rare earth transition metal alloys have perpendicular magnetic anisotropy and light
Excellent magnetic properties. Also, depending on its composition,
Control over a wide range of properties and magneto-optical properties
Yes. Such magnetic recording materials include TbCo and Tb.
Fe, TbFeCo, NdFeCo, GdFeCo, D
yFeCo, TbGdFe, TbNdFe, TbGdF
selected from Tb, Gd, Nd, and Dy, such as eCo
At least one rare earth metal and Fe or Co
Alloys in combination with any transition metal are preferred. Ma
In order to improve the corrosion resistance of these alloys, Cr and Ni
May be added as appropriate. In addition, it supplements the formation of magnetic domains.
For the purpose of assisting, Si or B may be added. The rare earth transition metal alloy depends on its composition.
It is known that the coercive force and the amount of magnetization change significantly,
Magnetic characteristics according to the recording method and the performance of the head used.
It is necessary to In normal magneto-optical recording, it is compensated at room temperature.
In order to design the composition of the magnetic recording layer to be a compensation composition,
Coercive force at room temperature is more than 10,000 Oersted (Oe)
The recording is very large unless heating with laser light is performed.
Have difficulty. The magnetic recording layer of the present embodiment has such a
Compensation composition may be used, but servo by magnetic transfer system
When using both signal recording and magnetic recording with a magnetic head
Is preferable as its coercive force 2000-8000 Oe
Or 3,000 to 6000 Oe. others
Select the type of rare earth element and transition metal element
Rare earth transition metal alloy rare
The earth content must be 10-25 atomic weight% (atm%).
There is a point. For example, in the case of TbFeCo, the above coercive force is reached.
The composition for forming Tb is 13-20 atm%, FeC
o is 80 to 87 atm%. The magnetic recording layer 16 is formed by sputtering.
It is preferable to make them. Depending on the sputtering method
It is easy to control the composition of the rare earth transition metal alloy.
The As a sputtering method, a general DC spa is used.
In addition to sputtering and RF sputtering, DC pulses
Patter, RF bias sputtering, reactive sputtering, etc.
Can be used. During sputtering, the constituent elements are
Independent targets on these targets
Co-sputtering, which rotates the plate,
Configure some or all of them as alloy targets and
Either method can be used. In addition, element distribution
And some reproducibility problems, but some of the basic targets
Install chips and sheets made of the elements you want to introduce into
A sputtering method of alloying with can also be used. Magnetism
The thickness of the air recording layer 16 is 10 nm to 100 nm.
Preferably, 20-50 nm is especially preferable. Thus, the rare earth transition metal alloy is used.
The perpendicular magnetic recording layer is produced by sputtering.
Can be formed at room temperature, so flexible polymer support
Despite using the body, there is no substrate deformation and it is flat
Excellent in properties. The protective layer 18 is included in the magnetic recording layer 16.
Prevents corrosion of metal material and makes pseudo contact between head and disk
Wear resistance by preventing wear caused by touch or contact sliding,
Provided to improve corrosion resistance. Rare earth transition metals
Since it is very easy to corrode, it is particularly preferable to provide a protective layer 18
preferable. The protective layer 18 includes silica, alumina, and titanium.
Such as near, zirconia, cobalt oxide, nickel oxide
Nitrogen such as oxide, titanium nitride, silicon nitride, boron nitride
Carbonization of chemicals, silicon carbide, chromium carbide, boron carbide, etc.
Materials such as carbon, graphite, and amorphous carbon
Can be used. As the protective layer 18, the head
Hard film with hardness equal to or higher than the material
It is difficult to cause seizure during sliding and the effect is stable.
What follows is superior in sliding durability and is more preferable
Yes. At the same time, the ones with few pinholes are resistant to corrosion.
It is excellent and more preferable. In addition, a laser tracker
Used to read the scanning signal with high accuracy.
It is preferable to have sufficient transparency to the laser beam.
Yes. Such a protective film is produced by a CVD method.
Hard called DLC (Diamond Like Carbon)
An example is a carbon film. The protective layer 18 includes two or more types having different properties.
It can be set as the structure which laminated | stacked the thin film. For example, the surface
Provide a hard carbon protective film to improve the sliding characteristics on the side,
Such as silicon nitride to improve corrosion resistance on the magnetic recording layer side.
Corrosion resistance and durability are high by providing a nitride protective film
It becomes possible to achieve both dimensions. On the protective layer 18, running durability and corrosion resistance are provided.
In order to improve the property, a lubricating film 20 is provided. Lubricating film
20 includes a known hydrocarbon-based lubricant, fluorine-based lubricant,
Lubricants such as extreme pressure additives are used. As the hydrocarbon lubricant, stearin
Acids, carboxylic acids such as oleic acid, butyl stearate
Esters such as, and sulfones such as octadecyl sulfonic acid
Acids, phosphate esters such as monooctadecyl phosphate,
Stecoal alcohol, oleyl alcohol, etc.
Carboxylic acid amides such as
Examples include amines such as stearylamine. Fluorine-based lubricants include the above hydrocarbon-based lubricants.
Remove some or all of the alkyl groups on the lubricant
Lubricants substituted with ruthenium groups or perfluoropolyether groups
A lubricant may be mentioned. As perfluoropolyether group
Is perfluoromethylene oxide polymer, perfluoro
Loethylene oxide polymer, perfluoro-n-propy
Ren oxide polymer (CF ₂ CF ₂ CF ₂ O) _n , Full
Oroisopropylene oxide polymer (CF (CF _Three ) C
F ₂ O) _n Or a copolymer thereof. Specifically
Perfluoromethylene having a hydroxyl group at the molecular weight end
-Perfluoroethylene copolymer (manufactured by Augmont,
Product name "FOMBLIN Z-DOL"). As an extreme pressure additive, trilauryl phosphate is used.
Phosphate esters such as trilauryl phosphite
Such as acid esters and trilauryl trithiophosphite
Ophosphite, thiophosphate, disulfide
And sulfur-based extreme pressure agents such as benzyl. The above lubricants may be used alone or in combination.
It is possible to use a solvent in which a lubricant is dissolved in an organic solvent.
Spin coating, wire bar coating, gravure
Apply to the surface of the protective layer 18 by a coat method, dip coat method, etc.
Cloth or adhere to the surface of the protective layer 18 by vacuum deposition
Just do it. As a coating amount of the lubricant, 1 to 30 mg / m
² 2-20 mg / m ² Is particularly preferred. In order to further improve the corrosion resistance, rust prevention
It is preferable to use an agent in combination. As rust inhibitor, benzo
Triazole, benzimidazole, purine, pyrimidi
Nitrogen-containing heterocycles such as
Derivatives introduced with side chains, benzothiazole, 2-mer
Kapton benzothiazole, tetrazaindene ring compound
And sulfur containing heterocycles such as thiouracil compounds
And derivatives thereof. These rust inhibitors are
It may be mixed with a lubricant and applied on the protective layer 18 to provide lubrication.
Before applying the agent, apply on the protective layer 18 and lubricate on it
An agent may be applied. As a coating amount of the rust preventive agent, 0.1
-10 mg / m ² Is preferably 0.5 to 5 mg / m ² Is special
Is preferred. Recording tracking signal on magneto-optical disk
That is, the method of preformatting the magnetic recording layer 16
The law is not particularly limited. For example, the magnetic head
The magnetization area may be written, and the magnetized area is formed by magnetic transfer.
It may be formed. A magnetized region with a fine pattern can be formed in a short time.
In order to form, magnetized region is formed by magnetic transfer
Is particularly preferred. Magnetic transfer is shown in FIGS. 2 (A) to 2 (C).
From the master carrier 24 on which the magnetic layer 28 is formed,
Slave medium 2 having magnetic recording layer 16 before being magnetized
2. Form magnetized region with a predetermined pattern by transferring magnetism
It is a method. Master carrier 24 is silicon, aluminum
Transfer onto the substrate 26 made of a non-magnetic material such as nickel.
Co, F with large magnetic flux density formed according to the pattern
A convex magnetic layer 28 made of a ferromagnetic material such as e was formed.
Between the substrate 26 and the magnetic layer 28 as necessary.
Depending on the conductivity made of non-magnetic metal material such as Cr and Ti
A sex layer can be provided. The master carrier 24 is
Used for fabrication and optical disk substrate formation
It can be manufactured using a stamper. For example,
Nickel substrate with a predetermined pattern formed by a stamper
A master carrier 24 can be obtained by forming a magnetic layer on
The The following is a method for forming a magnetized region by magnetic transfer.
Explain physically. First, as shown in FIG. 2A, the support 1
4, a magnetic recording layer 16 before being magnetized, a protective layer (illustrated)
And a slave medium in which a lubricating film (not shown) is laminated.
Apply a DC magnetic field in the direction of arrow A to the body 22,
The magnetic recording layer 16 of the medium 22 is excited in the direction of arrow A (first time
Phase magnetization). The magnetic recording layer 16 is initially magnetized and completely
The body becomes the magnetized region 16A. Next, as shown in FIG.
The carrier 24 is in close contact with the initially magnetized slave medium 22.
Let the transfer magnetic field be a DC magnetic field or AC in the direction of arrow B
A bias magnetic field is applied to excite the magnetic layer 28 in the direction of arrow B.
Magnetize. As a result, as shown in FIG.
From the portion where the magnetic medium 22 and the magnetic layer 28 are in contact, the magnetic
A magnetic field in the direction of arrow B is applied to the corresponding portion of the gas recording layer 16
As a result, the magnetization direction of the portion is reversed, and the magnetization region 16A
A magnetized region 16B is formed therein. Slave
A precise preformat of the medium 22 is performed. Next, recording information on the magneto-optical disk described above.
Recording and playback will be described. FIG. 5 shows the above magneto-optical device.
Used to record information on a disk and play back recorded information
FIG. 6 shows a schematic configuration of a recording / reproducing apparatus capable of performing
Shows the schematic configuration of the recording / reproducing head of the recording / reproducing apparatus.
The This recording / reproducing apparatus is shown in FIGS.
Attached to the tip of the swing arm 34
A flying slider that floats with the rotation of the magnetic disk 10
32. This floating slider 32 is a
Is a thin leaf spring fixed to the tip of the suspension 38
The suspension 3 is attached to the lower surface of the gimbal 52.
8 is supported by the swing arm 34. Also floating
The upper mold slider 32 has an air bearing surface (ABS: Air Bearin
g Surface) 40 faces the recording surface of the magneto-optical disk 10
So that it is disposed above the recording surface of the magneto-optical disk 10.
By swinging the swing arm 34 along the direction of arrow C.
Thus, the magneto-optical disk 10 can be moved in the radial direction.
Yes. As shown in FIG. 6, the recording / reproducing head unit
A floating slice that floats as the magneto-optical disk 10 rotates.
The air bearing surface 40 has a positive pressure or
A rail pattern 42 for applying negative pressure is provided.
Yes. When using near-field light as light, for example, floating
The air bearing surface 40 of the upper slider 32 is smaller than the wavelength of light.
A small opening 46 having a small diameter is provided. This minute aperture
In order to guide light from the outside to 46, the suspension 38 and
An optical fiber 44 is provided in parallel. Optical fiber 4
4 is disposed inside the floating slider 32, and is
Below the exit end of the fiber 44, light is transmitted to the minute aperture 46.
A condensing lens 47 for condensing light is disposed. Ma
On the air bearing surface 40, the magnetic head 5 provided with an exciting coil.
0 is provided, and the magnetic head 50 is applied during information recording.
Connected to a recording magnetic field control circuit 36 for controlling the magnetic field
The In this device, the light guided by the optical fiber 44
Is condensed on the minute aperture 46 by the condenser lens 47, and the minute aperture is obtained.
In the vicinity of the minute opening 46 by emitting from 46
Evanescent light 54 can be generated. While rotating the magneto-optical disk 10,
A floating slider 32 is attached to the magneto-optical disk 10.
When pressed, the magneto-optical disk 10 and the floating slider 3
2 is a stable contact sliding with a very weak force. Cheap head
For constant running, the disc rotation speed is 1000rpm ~
10,000 rpm is preferable, 2000 rpm to 750
0 rpm is more preferable. Also, disc runout is small
It is preferable to set it to about 50 μm or less.
More preferable. When recording information, this is a stable contact sliding.
Irradiate the magnetic recording layer 16 with evanescent light.
By doing so, the light-irradiated part is increased to the Curie temperature or higher.
Heat, sufficiently reduce the coercive force of the heated part, relatively small
It is easy to reverse magnetization even with a strong magnetic field strength. And recording magnetic field
A control signal is supplied from the control circuit 36 to the magnetic head 50;
Reversing the magnetization of the magnetic recording layer 16 with a magnetic field corresponding to the information
By applying it to areas that have become easier,
Recording is performed (magnetic field modulation magneto-optical recording method). Magnetic field
When information is recorded by the modulation method, it is shown in FIG.
As shown in FIG.
Therefore, the recording size is approximately the same as the recording mark 56 of the magnetic head.
Recording signals 58 are continuously recorded. In addition, information is recorded on the magneto-optical disk 10.
As explained below, the magnetic Kerr effect is
Tracking servo is performed. FIG. 3 (A)
As shown in FIG. 3, the support side is the S pole and the recording surface side is the N pole.
Irradiate linearly polarized light to the magnetized region 16A magnetized in the direction
The polarization plane of the reflected light is incident light due to the magnetic Kerr effect.
Rotate from the plane of polarization by a predetermined angle θ (eg clockwise)
The On the other hand, as shown in FIG.
Magnetized region 16B magnetized in the direction in which the recording surface side becomes the south pole
When the same linearly polarized light is irradiated to the
The polarization plane of the reflected light is a predetermined angle −θ from the polarization plane of the incident light.
Rotate only (for example, counterclockwise). Therefore, as recording light
The irradiated evanescent light is applied to the magneto-optical disk 10.
Although it is reflected more, it is polarized from this reflected light through a polarizing plate etc.
The reflected light whose surface has been rotated by a predetermined angle is detected and reflected.
The relative deviation between the head and track is detected by the light intensity.
Tracking servo. Immediately
I.e., magnetized regions concentrically or spirally
16A and the magnetized region 16B are a tracking guide and
To play a role. Tracking error detection
As a method, a two-divided photo detector is used.
Push-pull method to obtain King error signal, 3-beam method, etc.
Tracking error detection used on optical discs
The exit method can be used. Enough tracking
In order to obtain an error signal, the three beam method is preferable. Regarding the focus servo using light,
A piezo element-like disk like the current magneto-optical disk drive.
Focusing may be performed, but the tracking of the present embodiment.
In the king method, the flying head is very
Focus servo mechanism is omitted to follow with high accuracy
It is also possible to do. This miniaturizes the drive device,
This is very advantageous for reducing the thickness. Information reproduction is based on the electric resistance depending on the strength of the magnetic field.
MR (Magneto) using magnetoresistive effect that changes resistance
Resistive) head, GMR head, TMR head, etc.
You may carry out using a magnetic head. Above all, high sensitivity G
MR heads and TMR heads are particularly preferred. In addition,
As described below, the magnetic car effect is used to
Information to the magneto-optical disk 10 while performing
Information is recorded. Also, the same as a normal magneto-optical disk
Similarly, it is also possible to read the recording signal with a laser beam. As described above, the light according to the present embodiment
For magnetic disks: (1) Use a flexible polymer support such as a resin film.
It was configured as a so-called flexible disk.
In the case where the magnetic head is arranged in the very vicinity of the recording medium,
The impact at the time of contact with the magnetic head is avoided, and the magneto-optical disk is avoided.
The magnetic head and the magnetic head slide stably in contact with a very weak force.
There is an advantage that. When recording to a hard disk, a low
Head with air bearing design to achieve ing height
A slider is used, but this head slider
When used for flexible disks, the support is flexible
Because of its stability, a stable air bearing is not formed,
It becomes a state of pseudo contact or contact sliding. This pseudo contact
In the state of contact sliding, the distance between the disk and head
Since it can be made small, it is very effective for high-density recording.
The In the case of a hard disk, magnetic
The head and disk are easily damaged by the impact of contact
There is a problem of low, but in the case of flexible disk
If the magnetic head is in contact with the disk,
Can reduce the contact impact.
Yes. Therefore, flexible disks are highly reliable.
Contact recording is possible. (2) Flexible polymer support such as resin film
As a so-called flexible disk using a holder
Because it is configured, it is possible to manufacture magneto-optical disks at low cost.
it can. Flexible polymer supports such as resin films are
It is less expensive than a glass substrate or an aluminum substrate. In addition, the hard disk has a predetermined size.
Each glass substrate or aluminum substrate is mirror-polished one by one,
Magnetic film, protective film, and lubricating film on this mirror-polished substrate
It is possible to use resin films, etc.
If a flexible polymer support is used, a web-like support
While transporting the carrier, a magnetic film, a protective film,
Lubricating film is continuously laminated, and the required size is
It is possible to make a magneto-optical disk by punching the disk.
it can. A large number of magneto-optical disks are produced at this time.
With less disk size constraints
Therefore, manufacturing cost can be reduced. Especially this effect
The result is on a small-diameter disk medium of 2.5 inches or less.
Become prominent. (3) Magnetic recording made of rare earth transition metal alloy
Since it has a recording layer, high-density recording by perpendicular magnetic recording
Is possible. This rare earth transition metal has perpendicular magnetic anisotropy.
It is large and can increase coercivity, so it is very small
Even with a large recording magnetization bit, it can exist thermally and stably.
Therefore, ultra-high density recording is possible. (4) Magnetic recording layers have different magnetization directions in advance
Magnetized so that the magnetized regions are arranged alternately in the radial direction
Therefore, based on the difference in the magnetization direction of the magnetization region,
Racking can be performed. As you can see, the magnetization region
Tracking based on the difference in magnetization direction
Therefore, it is not necessary to form irregularities on the medium surface, and
Even when the disk is placed very close to the recording medium,
The traveling state can be realized. (5) The magnetic recording layer is previously set in the center of the disk.
Since it is magnetized concentrically or spirally,
Tracking can be performed continuously and accurate tracking
Can perform king servo, signal with good S / N
Can be recorded and reproduced. Also pre-magnetized
Since information is recorded in the magnetized area, the area of the servo area
A decrease in recording capacity due to an increase can be prevented. Special
On the other hand, flexible disks are compared with hard disks.
Compared with the rotation of the medium, the support is greatly deformed and vibrated,
Although this hinders high-density recording, the magneto-optics of this embodiment
For Ki discs, accurate tracking servo can be performed.
And tracking errors are less likely to occur.
Achieve track density comparable to that of discs and optical discs
You can. (6) The magnetization direction of the magnetization region is set to the disk surface.
By arranging them vertically, they are alternately arranged in the radial direction.
Magnetized regions with different magnetization directions weaken their magnetic force
The magnetic force of each magnetization region is stabilized.
The (7) Based on the difference in the magnetization direction of the magnetization region
So that it can be tracked.
It is not necessary to form irregularities on a smooth substrate.
Next-generation high-density recording method using hybrid light, hybrid
As in the magneto-optical recording method, the head is located very close to the recording medium.
To achieve a stable head running state.
Can. (8) Magnetizing the region by so-called magnetic transfer
A large amount of servo information is created when a magnetic field is applied.
Can be copied all at once, in an extremely short time
The magnetization region can be magnetized. Therefore, productivity is high
In addition, the manufacturing cost of the recording medium can be kept low.
Also, since it can be statically magnetized, an accurate pre-
Format recording is possible. In the above embodiment, the magnetic recording layer
Record and playback information by irradiating laser light from the side
I explained an example, but irradiate a laser beam from the substrate side.
A configuration for recording and reproducing information can also be adopted. This
In this case, the support has a predetermined wavelength used for recording and reproduction.
A material having a high transmittance with respect to the laser beam is used. Further, in the above embodiment, the piece of the support body
The example in which the magnetic recording layer is provided on the surface has been described.
Magnetic recording layers may be provided on both sides. Also, one side is magnetic
Pastes the support with the recording layer with the support side inside
In addition, magnetic recording layers may be provided on both sides of the disk.
Yes. In the above embodiment, evanescent light is used.
The example of recording and playback using the
Using other laser light sources commonly used in information recording equipment
Recording and playback. As other laser light source
For example, it has an oscillation wavelength in the range of 400 to 780 nm.
A semiconductor laser can be used. Recording density
For example, a blue-violet semiconductor such as a GaN laser
Laser, infrared semiconductor laser and wavelength conversion element (SHG)
It is preferable to use a blue-violet SHG laser composed of
A blue-violet semiconductor laser with a wavelength of around 405 nm is particularly desirable.
Is preferred. In addition, evanescent light is emitted by a small aperture.
The example using the generating device has been described.
A device that collects light on L and generates evanescent light
It can also be used for recording and reproduction. In this device,
As shown in FIG.
The exit surface is exposed to the floating surface 40 of the floating slider 32
SIL60 is embedded. Above SIL60
Condensing light from outside the floating slider 32
The lens 62 emits the SIL 60 exposed on the air bearing surface 40.
It is arranged to focus on the surface. Condensing lens 62
The light from outside the floating slider 32 is collected by
Near focus by focusing on the exit surface of L60
Evanescent light 54 is generated. As shown in FIG.
Components that are the same as those of the device are given the same reference numerals for explanation.
Omitted. In the above embodiment, the magnetic field modulation method is used.
An example of recording information is described.
As shown, either the magnetization region 16A or the magnetization region 16B
On the other hand, a magnetic field opposite to the magnetization direction is applied to the laser
Only the part irradiated with light 30 is reversed in magnetization, and magnetically
Information can also be recorded (light modulation method). this
When the intensity distribution of the laser beam is Gaussian
Therefore, the recording signal 31 is at the center of the spot having a high intensity.
It is formed. For this reason, it is smaller than the spot of the laser beam 30.
The recording signal 31 is recorded according to the recording signal. Ma
In addition, as shown in FIG. 4, for example, the S-type magnetization region 16B
The N-type magnetized region 16A is used only for tracking.
Magnetization area and information for tracking, such as used for
Divided into magnetized areas for recording
Information may be recorded. The information recording medium of the present invention has a large storage capacity.
And the head is placed in the immediate vicinity of the recording medium.
The effect that stable head running is possible even if
Play. Also, the information recording medium of the present invention is manufactured at a low cost.
There is an effect that it can be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a plan view showing a schematic configuration of a magneto-optical disk according to the present embodiment, and FIG. 1B is a magnetic recording layer in region A of FIG. It is the elements on larger scale which show the magnetization state of the surface, (C) is the sectional view on the AA line of (B). FIGS. 2A to 2C are cross-sectional views illustrating a magnetic transfer process. FIGS. FIGS. 3A and 3B are explanatory diagrams for explaining the principle of reading a tracking signal. FIGS. FIG. 4 is a plan view showing a recording pattern when information is recorded by a light modulation method. FIG. 5 is a plan view showing a schematic configuration of a recording / reproducing apparatus used for recording and reproducing information on a magneto-optical disk according to the present embodiment. 6 is a cross-sectional view along the optical axis showing a schematic configuration of a recording / reproducing head unit of the recording / reproducing apparatus shown in FIG. 5; FIG. 7 is a plan view showing a recording pattern when information is recorded by a magnetic field modulation method. FIG. 8 is a plan view showing another configuration example of the recording / reproducing apparatus used for recording and reproducing information on the magneto-optical disk according to the present embodiment. [Description of Symbols] 10 Magneto-optical disk 12 Cartridge 14 Support 15 Underlayer 16 Magnetic recording layer 16A Magnetized region 16B Magnetized region 18 Protective layer 20 Lubricating film 22 Slave medium 24 Master carrier 32 Floating slider 50 Magnetic head

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuo Nagao             12-12 Ogimachi, Odawara-shi, Kanagawa Pref.             Shishi Photo Film Co., Ltd. F-term (reference) 5D006 BB01 CB07 DA02 DA08 FA00                 5D075 EE03 FF04 FG15

Claims (1)

What is claimed is: 1. A flexible polymer support; and a perpendicular magneto-optical recording layer comprising a rare earth transition metal alloy provided on at least one surface of the flexible polymer support; Including information recording medium.