JP2005141808A - Optical information recording medium and optical information recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium, wherein wobble amplitude is optimized and which has satisfactory reproduced signal intensities and recording characteristics, and to provide an optical information recording method using the optical information recording medium. <P>SOLUTION: The optical information recording medium, having a postscript-type recording layer, containing a dye and a protective substrate having 0.1 to 1.0 mm thickness on a substrate, having 0.1 to 1.0 mm thickness, in this order has a pre-groove formed in the substrate having 200 to 600 nm track pitch, 50 to 300 nm groove width, 30 to 200 nm groove depth and 10 to 50 nm wobble amplitude. In the optical information recording method, recording is performed by having the optical information recording medium irradiated with a laser beam having 100 to 600 nm wavelength from the substrate side or the protective substrate side to form pits in the postscript-type recording layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical information recording medium capable of recording and reproducing using a laser beam having a specific wavelength, and an optical information recording method using the optical information recording medium. The present invention relates to an information recording medium and an optical information recording method using the optical information recording medium.

  Conventionally, an optical information recording medium (optical disc) capable of recording information only once by laser light is known. This optical disk is also called a recordable CD (so-called CD-R), and its typical structure is a recording layer made of an organic dye on a transparent disk-shaped substrate, a light reflecting layer made of a metal such as gold, and a resin. A protective layer (cover layer) made in this order is laminated in this order. Information recording on this CD-R is performed by irradiating the CD-R with a near-infrared laser beam (usually a laser beam having a wavelength of around 780 nm), and the irradiated portion of the recording layer emits the light. Information is recorded by absorbing and locally raising the temperature, and changing the optical characteristics of the portion due to physical or chemical changes (for example, generation of pits). On the other hand, reading (reproduction) of information is also performed by irradiating the CD-R with laser light having the same wavelength as the recording laser light, and the optical characteristics of the recording layer (recording portion) change. This is done by detecting a difference in reflectance from a non-recorded part (unrecorded part).

  In recent years, an optical information recording medium having a higher recording density has been demanded. In response to such a demand, an optical disk called a write-once digital versatile disk (so-called DVD-R) has been proposed (for example, “Nikkei New Media”, separate volume “DVD”, published in 1995). This DVD-R has a transparent disk shape in which a guide groove (pre-groove) for tracking the irradiated laser beam is formed with a narrow groove width of less than half (0.74 to 0.8 μm) of the CD-R. A structure in which two discs, in which a recording layer containing an organic dye, a light reflecting layer, and a protective layer are laminated in this order on a substrate, are bonded together with the recording layer inside, or a disc shape having the same shape as this disc It has a structure in which a protective substrate is bonded with the recording layer inside. Recording and reproduction of information on the DVD-R is performed by irradiating with visible laser light (usually laser light having a wavelength in the range of 630 nm to 680 nm), which has a higher density than the CD-R. Recording is possible.

  Recently, networks such as the Internet and high-definition TV are rapidly spreading. Also, the start of HDTV (High Definition Television) has started. Under such circumstances, a large-capacity recording medium capable of recording image information inexpensively and simply is required. DVD-R plays a role as a large-capacity recording medium at present, but the demand for larger capacity and higher density is increasing, and development of a recording medium that can meet these demands is also necessary. . For this reason, development of a recording medium having a larger capacity capable of performing high-density recording with light having a shorter wavelength than that of the DVD-R is underway.

  For example, in an optical information recording medium having a recording layer containing an organic dye, a recording / reproducing method for recording and reproducing information by irradiating a laser beam having a wavelength of 530 nm or less has been proposed (for example, Patent Documents 1 to 3). 15). In these methods, an optical disc including a recording layer containing a porphyrin compound, an azo dye, a metal azo dye, a quinophthalone dye, a trimethine cyanine dye, a dicyanovinylphenyl skeleton dye, a coumarin compound, a naphthalocyanine compound, Information is recorded and reproduced by irradiating blue (wavelength 430 nm, 488 nm) or blue-green (wavelength 515 nm) laser light.

An optical information recording medium that performs recording and reproduction using such short-wavelength light uses a substrate on which a pregroove having a groove shape suitable for the layer configuration and characteristics is formed. However, in an optical information recording medium that uses light of a short wavelength and has a laminated layer structure such as the above-mentioned DVD-R, a groove shape suitable for these layer structure and characteristics, particularly wobble amplitude. The optimal number has not yet been found.
JP-A-4-74690 JP-A-7-304256 JP-A-7-304257 JP-A-8-127174 Japanese Patent Laid-Open No. 11-53758 JP-A-11-334204 JP 11-334205 A Japanese Patent Laid-Open No. 11-334206 JP 11-334207 A JP 2000-43423 A JP 2000-108513 A JP 2000-113504 A JP 2000-149320 A JP 2000-158818 A JP 2000-228028 A

  The present invention has been made in view of the above problems, and an object of the present invention is to optimize the wobble amplitude of a substrate in an optical information recording medium having a bonded layer structure, and to reproduce a reproduced signal. An object is to provide an optical information recording medium having good strength and recording characteristics, and an optical information recording method using the optical information recording medium.

The above problems are solved by the present invention described below.
That is, the optical information recording medium of the present invention is
An optical information recording medium having a write-once recording layer containing a dye and a protective substrate having a thickness of 0.1 to 1.0 mm in this order on a substrate having a thickness of 0.1 to 1.0 mm,
The pregroove formed on the substrate has a track pitch of 200 to 600 nm, a groove width of 50 to 300 nm, a groove depth of 30 to 200 nm, and a wobble amplitude of 10 to 50 nm.

The optical information recording method of the present invention comprises a write-once recording layer containing a dye and a protective substrate having a thickness of 0.1 to 1.0 mm on a substrate having a thickness of 0.1 to 1.0 mm. An optical information recording method for performing recording by irradiating a laser beam having a wavelength of 100 to 600 nm from the substrate or the protective substrate side to the optical information recording medium having this order and forming pits in the write-once recording layer. ,
The pregroove formed on the substrate has a track pitch of 200 to 600 nm, a groove width of 50 to 300 nm, a groove depth of 30 to 200 nm, and a wobble amplitude of 10 to 50 nm.

  According to the present invention, it is possible to provide an optical information recording medium having good reproduction signal intensity and recording characteristics, and an optical information recording method capable of imparting good and stable recording / reproduction characteristics.

Hereinafter, the present invention will be described in detail.
<Optical information recording medium>
The optical information recording medium of the present invention comprises a write-once recording layer containing a dye and a protective substrate having a thickness of 0.1 to 1.0 mm in this order on a substrate having a thickness of 0.1 to 1.0 mm. An optical information recording medium comprising:
The pregroove formed on the substrate has a track pitch of 200 to 600 nm, a groove width of 50 to 300 nm, a groove depth of 30 to 200 nm, and a wobble amplitude of 10 to 50 nm.

Here, the optical information recording medium of the present invention is an optical information recording medium having a bonded layer structure, and typical layer structures thereof are as follows.
(1) The first layer configuration is a configuration in which a write-once recording layer, a light reflection layer, and an adhesive layer are sequentially formed on a substrate, and a protective substrate is provided on the adhesive layer.
(2) The second layer configuration is a configuration in which a write-once recording layer, a light reflection layer, a protective layer, and an adhesive layer are sequentially formed on a substrate, and a protective substrate is provided on the adhesive layer.
(3) The third layer configuration is a configuration in which a write-once recording layer, a light reflection layer, a protective layer, an adhesive layer, and a protective layer are sequentially formed on a substrate, and a protective substrate is provided on the protective layer.
(4) In the fourth layer configuration, a write-once recording layer, a light reflecting layer, a protective layer, an adhesive layer, a protective layer, and a light reflecting layer are sequentially formed on a substrate, and a protective substrate is provided on the light reflecting layer. It is a configuration.
(5) The fifth layer configuration is a configuration in which a write-once recording layer, a light reflecting layer, an adhesive layer, and a light reflecting layer are sequentially formed on a substrate, and a protective substrate is provided on the light reflecting layer.
Note that the layer configurations (1) to (5) are merely examples, and the layer configuration is not limited to the order described above, and a part of the layer configuration may be replaced or a part of the layer configuration may be omitted. The write-once recording layer may also be formed on the protective substrate side. In this case, an optical information recording medium capable of recording and reproducing from both sides is obtained. Furthermore, each layer may be composed of one layer or a plurality of layers.
As an example of the optical information recording medium of the present invention, a recording medium having a write-once recording layer, a light reflecting layer, an adhesive layer, and a protective substrate in this order will be described below.

〔substrate〕
It is essential that the substrate in the present invention has a pregroove (guide groove) having a shape in which all of the track pitch, groove width (half width), groove depth, and wobble amplitude are in the following ranges. It is. This pre-groove is provided to achieve a higher recording density than CD-R and DVD-R. For example, the optical information recording medium of the present invention is used as a medium corresponding to a blue-violet laser. It is suitable for use.

The track pitch of the pregroove is essential to be in the range of 200 to 600 nm, and the upper limit is preferably 500 nm or less, more preferably 450 nm or less, and further preferably 430 nm or less. The lower limit is preferably 300 nm or more, more preferably 330 nm or more, and still more preferably 370 nm or more.
If the track pitch is less than 200 nm, it is difficult to form the pregroove accurately, and a crosstalk problem may occur. If the track pitch exceeds 600 nm, the recording density may decrease.

The groove width (half width) of the pregroove is in the range of 50 to 300 nm, the upper limit is preferably 250 nm or less, more preferably 200 nm or less, and 180 nm or less. Further preferred. Further, the lower limit value is preferably 100 nm or more, more preferably 120 nm or more, and further preferably 140 nm or more.
If the groove width of the pregroove is less than 50 nm, the groove may not be sufficiently transferred at the time of molding or the recording error rate may be high. If it exceeds 300 nm, the pits formed at the time of recording spread. It may cause crosstalk or a sufficient degree of modulation may not be obtained.

The groove depth of the pregroove is essential to be in the range of 30 to 200 nm, the upper limit is preferably 170 nm or less, more preferably 140 nm or less, and further preferably 120 nm or less. The lower limit is preferably 40 nm or more, more preferably 50 nm or more, and further preferably 60 nm or more.
When the groove depth of the pregroove is less than 30 nm, a sufficient recording modulation degree may not be obtained, and when it exceeds 200 nm, the reflectivity may be significantly lowered.

In addition, the groove inclination angle of the pregroove is preferably 80 ° or less, more preferably 70 ° or less, still more preferably 60 ° or less, and particularly preferably 50 ° or less. preferable. Further, the lower limit value is preferably 20 ° or more, more preferably 30 ° or more, and further preferably 40 ° or more.
If the groove inclination angle of the pregroove is less than 20 °, a sufficient tracking error signal amplitude may not be obtained, and if it exceeds 80 °, molding becomes difficult.

Furthermore, in the present invention, it is essential that the wobble amplitude of the pregroove is 10 to 50 nm, and the upper limit value is preferably 40 nm or less, more preferably 37 nm or less, and 33 nm or less. Further preferred. The lower limit is preferably 15 nm or more, more preferably 20 nm or more, and further preferably 23 nm or more.
If the wobble amplitude is less than 10 nm, the wobble signal intensity during reproduction may decrease, and if it exceeds 50 nm, the jitter during recording may increase. In any case, a practical problem occurs.
In addition, the preferred range for the wobble frequency is 0.1 to 10 MHz.

Here, the groove width W, the groove depth D, and the angle (groove inclination angle θ) are defined using the schematic cross-sectional view showing the shape of the pregroove in FIG. As shown in FIG. 1, the groove depth D of the pregroove is a distance from the substrate surface before the groove formation to the deepest portion of the groove, and the groove width W of the pregroove is a groove at a depth of D / 2. The groove inclination angle θ of the pregroove is a straight line connecting the inclined portion having a depth of D / 10 from the substrate surface before the groove is formed and the inclined portion having a height of D / 10 from the deepest portion of the groove. And the substrate surface.
The track pitch of the pregroove is a distance between the pregrooves, and specifically indicates a distance between centerlines of the pregroove.
In addition, the value of the shape of these pregrooves can be measured by AFM (atomic force microscope).
The wobble amplitude is measured by condensing and irradiating a laser with an optical pickup and detecting a reproduction signal by the reflected light.

In order to produce a substrate having a pregroove having such a groove shape, a stamper used at the time of injection molding needs to be formed by highly accurate mastering. In order to achieve the above-mentioned groove shape, it is preferable to use DUV (wavelength 330 nm or less, deep ultraviolet) laser or EB (electron beam) cutting for this mastering.
On the other hand, with a UV laser or a visible light laser, it is difficult to perform good mastering for forming the groove shape as in the present invention.

As the substrate used in the present invention, various materials used as substrate materials for conventional optical information recording media can be arbitrarily selected and used.
Specifically, glass; acrylic resin such as polycarbonate and polymethyl methacrylate; vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin; amorphous polyolefin; polyester; metal such as aluminum; These may be used together if desired.
Among the above materials, thermoplastic resins such as amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable from the viewpoints of moisture resistance, dimensional stability, and low price.
When these resins are used, the substrate can be manufactured by injection molding.
Further, the thickness of the substrate needs to be in the range of 0.1 to 1.0 mm, preferably in the range of 0.2 to 0.8 mm, and in the range of 0.3 to 0.7 mm. It is more preferable.

An undercoat layer is preferably formed on the surface of the substrate on the side where a write-once recording layer, which will be described later, is provided for the purpose of improving flatness and adhesion.
Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, and chloro. Polymer materials such as sulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc .; silane coupling Surface modifiers such as agents;
The undercoat layer is formed by dissolving or dispersing the above materials in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, and preferably in the range of 0.01 to 10 μm.

[Write-once recording layer]
The write-once recording layer in the present invention is a recording layer containing a dye and capable of recording information only once with a laser beam. In particular, the write-once recording layer in the present invention is preferably capable of recording information with a laser beam having a wavelength region of 100 to 600 nm, and preferably contains a dye having absorption in the same wavelength region. Examples of the dye include a cyanine dye, an oxonol dye, a metal complex dye, an azo dye, and a phthalocyanine dye.

  JP-A-4-74690, JP-A-8-127174, 11-53758, 11-334204, 11-334205, 11-334206, 11-334207 The dyes described in JP-A No. 2000-43423, JP-A No. 2000-108513, JP-A No. 2000-158818, and the like are also preferably used.

A write-once recording layer is prepared by dissolving a dye in a suitable solvent together with a binder and the like to prepare a coating solution, and then coating the coating solution on a substrate or a light reflecting layer described later to form a coating film. Then, it is formed by drying. Here, the write-once recording layer may be a single layer or a multilayer. In the case of a multilayer structure, the step of applying the coating liquid is performed a plurality of times.
The concentration of the dye in the coating solution is generally in the range of 0.01 to 15% by mass, preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.5 to 5% by mass, most preferably. It is the range of 0.5-3 mass%.

Examples of the solvent for the coating solution include esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; dimethylformamide and the like Amides; Hydrocarbons such as methylcyclohexane; Ethers such as tetrahydrofuran, ethyl ether, dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol diacetone alcohol; 2,2,3,3-tetrafluoropropanol, etc. Fluorinated solvents; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether; That.
The said solvent can be used individually or in combination of 2 or more types in consideration of the solubility of the pigment | dye to be used. In the coating solution, various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be added according to the purpose.

Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method.
At the time of application, the temperature of the coating solution is preferably in the range of 23 to 50 ° C, more preferably in the range of 24 to 40 ° C, and particularly preferably in the range of 23 to 50 ° C.

The thickness of the write-once recording layer thus formed is preferably 400 nm or less, more preferably 300 nm or less, and further preferably 250 nm or less on the groove (the concave portion in the substrate). preferable. The lower limit is preferably 50 nm or more, more preferably 70 nm or more, still more preferably 90 nm or more, and particularly preferably 110 nm or more. .
Further, the thickness of the write-once recording layer is preferably 300 nm or less, more preferably 250 nm or less, still more preferably 200 nm or less, and 180 nm or less on the land (convex portion in the substrate). It is particularly preferred that The lower limit is preferably 30 nm or more, more preferably 50 nm or more, still more preferably 70 nm or more, and particularly preferably 90 nm or more.
Further, the ratio of the thickness of the write-once recording layer on the land / the thickness of the write-once recording layer on the groove is preferably 0.4 or more, more preferably 0.5 or more. 6 or more is more preferable, and 0.7 or more is particularly preferable. The upper limit is preferably less than 1, more preferably 0.9 or less, still more preferably 0.85 or less, and particularly preferably 0.8 or less.

  When the coating solution contains a binder, examples of the binder include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin, and rubber; hydrocarbon resins such as polyethylene, polypropylene, polystyrene, and polyisobutylene. , Polyvinyl chloride, polyvinylidene chloride, vinyl resins such as polyvinyl chloride / polyvinyl acetate copolymer, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral And synthetic organic polymers such as resins, rubber derivatives, and initial condensates of thermosetting resins such as phenol / formaldehyde resins. When a binder is used in combination as a material for the write-once recording layer, the amount of binder used is generally in the range of 0.01 to 50 times (mass ratio) with respect to the dye, preferably 0.1. It exists in the range of double amount-5 times amount (mass ratio).

In addition, the write-once recording layer can contain various anti-fading agents in order to improve the light resistance of the write-once recording layer.
As the antifading agent, a singlet oxygen quencher is generally used. As the singlet oxygen quencher, those described in publications such as known patent specifications can be used.
Specific examples thereof include JP-A Nos. 58-175893, 59-81194, 60-18387, 60-19586, 60-19587, and 60-35054. 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, JP-A-60-47069, JP-A-63-209995, JP-A-4-25492, JP-B-1-38680, JP-A-6-26028, etc., German Patent No. 350399, and Japan Examples include those described in Chemical Society Journal, October 1992, page 1141.
The amount of the antifading agent such as the singlet oxygen quencher used is usually in the range of 0.1 to 50% by weight, preferably in the range of 0.5 to 45% by weight, based on the amount of the dye. Preferably, it is the range of 3-40 mass%, Most preferably, it is the range of 5-25 mass%.

(Light reflection layer)
In the present invention, a light reflection layer may be formed on the write-once recording layer in order to increase the reflectance with respect to the laser beam or to provide a function of improving the recording / reproducing characteristics.
The light reflecting layer can be formed on the substrate or the write-once recording layer by vacuum-depositing, sputtering, or ion plating a light reflecting material having a high reflectivity with respect to the laser beam.
The thickness of the light reflecting layer is generally in the range of 10 to 300 nm, and preferably in the range of 50 to 200 nm.
The reflectance is preferably 70% or more.

  As a light reflective material having a high reflectance, Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd , Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, and other metals and metalloids or stainless steel. These light reflecting substances may be used alone, or may be used in combination of two or more kinds or as an alloy. Among these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred is Au, Ag, Al or an alloy thereof, and most preferred is Au, Ag or an alloy thereof.

[Adhesive layer]
The adhesive layer in the present invention is an arbitrary layer formed in order to improve the adhesion between the light reflecting layer and the protective substrate.
As a material constituting the adhesive layer, a photo-curing resin is preferable, and in particular, a material having a small curing shrinkage rate is preferable in order to prevent the disk from warping. Examples of such a photocurable resin include UV curable resins (UV curable adhesives) such as “SD-640” and “SD-347” manufactured by Dainippon Ink, Inc. In addition, the thickness of the adhesive layer is preferably in the range of 1 to 1000 μm in order to give elasticity.

[Protection board]
The protective substrate (dummy substrate) in the present invention can be made of the same material and the same shape as those described above.
The thickness of the protective substrate requires a thickness in the range of 0.1 to 1.0 mm, preferably in the range of 0.2 to 0.8 mm, and in the range of 0.3 to 0.7 mm. It is more preferable that

[Protective layer]
In the optical information recording medium of the present invention, a protective layer may be provided for the purpose of physically and chemically protecting the light reflecting layer, the write-once recording layer, and the like depending on the layer structure.
Examples of materials used for the protective layer include inorganic substances such as ZnS, ZnS—SiO ₂ , SiO, SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N ₄ , thermoplastic resins, thermosetting resins, and UV curable materials. Organic substances such as resins can be mentioned.
The protective layer can be formed, for example, by bonding a film obtained by plastic extrusion onto the light reflecting layer via an adhesive. Moreover, you may provide by methods, such as vacuum evaporation, sputtering, and application | coating.

Further, when a thermoplastic resin or a thermosetting resin is used as the protective layer, it is also formed by dissolving these in an appropriate solvent to prepare a coating solution, and then applying and drying the coating solution. be able to. In the case of a UV curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, and then applying the coating solution and curing it by irradiation with UV light. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose.
The thickness of the protective layer is generally in the range of 0.1 μm to 1 mm.

[Other layers]
The optical information recording medium of the present invention may have other arbitrary layers in addition to the above-mentioned layers as long as the effects of the present invention are not impaired. Such other optional layers include, for example, a label layer having a desired image formed on the back surface of the substrate (the back surface with respect to the write-once recording layer forming side), or between the light reflection layer and the write-once recording layer. Or an interface layer provided between the substrate and the write-once recording layer.
The label layer is formed using an ultraviolet curable resin, a thermosetting resin, a heat drying resin, or the like.
In addition, the interface layer is provided for adjusting the reflectance, adjusting the thermal conductivity, improving the recording / reproducing characteristics, etc., and can transmit light used for recording and reproducing. It is preferably made of a material with low permeability (for example, oxide or nitride).
Any of these arbitrary layers may be a single layer or may have a multilayer structure.

  Since the optical information recording medium of the present invention having the various layers as described above has optimized the wobble amplitude of the pregroove, the reproduction signal and recording characteristics are good.

<Optical information recording method>
The optical information recording method of the present invention comprises a write-once recording layer containing a dye and a protective substrate having a thickness of 0.1 to 1.0 mm in this order on a substrate having a thickness of 0.1 to 1.0 mm. An optical information recording method for performing recording by irradiating a laser beam having a wavelength of 100 to 600 nm from the substrate or the protective substrate side to the optical information recording medium having, and forming pits in the write-once recording layer,
The pregroove formed on the substrate has a track pitch of 200 to 600 nm, a groove width of 50 to 300 nm, a groove depth of 30 to 200 nm, and a wobble amplitude of 10 to 50 nm.
That is, in the optical information recording method of the present invention, when recording is performed on the above-described optical information recording medium of the present invention, it is necessary to irradiate laser light having a wavelength of 100 to 600 nm.
As in the optical information recording method of the present invention, recording is performed by irradiating an optical information recording medium having a specific pre-groove by irradiating a laser beam having a suitable wavelength, thereby providing good and stable recording / reproducing characteristics. be able to.

More preferably, the lower limit of the recording wavelength (laser light wavelength) is 200 nm or more, more preferably 300 nm or more, and particularly preferably 350 nm or more. Moreover, as an upper limit, it is more preferable that it is 500 nm or less, It is further more preferable that it is 450 nm or less, It is especially preferable that it is 420 nm or less.
Information may be recorded on the groove of the optical information recording medium of the present invention or on the land, but the groove is preferred.
Furthermore, information is also reproduced by the laser beam in the above wavelength region.

More specifically, the optical information recording medium of the present invention having a write-once recording layer, a light reflecting layer, an adhesive layer, and a protective substrate in this order on a substrate, and the optical information recording method of the present invention are used. For example, the recorded information is recorded and reproduced as follows.
First, a blue-violet laser (for example, wavelength 405 nm) is passed through the objective lens from the substrate side while rotating the optical information recording medium at a predetermined linear velocity (0.5 to 10 m / sec) or a predetermined constant angular velocity. Irradiate recording light. With this irradiation light, the write-once recording layer absorbs the light and the temperature rises locally. For example, information is recorded by generating pits and changing the optical characteristics. Reproduction of information recorded as described above is performed by irradiating a blue-violet laser beam from the cover layer side and detecting the reflected light while rotating the optical information recording medium at a predetermined constant linear velocity. Can do. When the optical information recording medium of the present invention has a layer configuration capable of recording and reproduction from both sides, or a layer configuration capable of recording and reproduction from the protective substrate side, a laser is emitted from the protective substrate side. By irradiating light, recording and reproduction similar to the above can be performed.

Examples of the laser light source having an oscillation wavelength of 500 nm or less as described above include a blue-violet semiconductor laser having an oscillation wavelength in the range of 390 to 415 nm, a blue-violet SHG laser having a central oscillation wavelength of 425 nm, and the like.
In order to increase the recording density, the NA of the objective lens used for the pickup is preferably 0.55 or more, and more preferably 0.6 or more.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Examples 1-6, Comparative Examples 1 and 2)
<Manufacture of optical information recording media>
(Production of substrate)
Thickness 0.6mm, outer diameter 120mm, inner diameter 15mm and spiral pre-groove (track pitch, groove width, groove depth, (groove inclination angle), wobble amplitude and wobble frequency are listed in Table 1 below) An injection-molded substrate made of polycarbonate resin was prepared.
The mastering of the stamper used at the time of injection molding was performed using the cutting means described in Table 1 below. In Table 1, “DUV” of the cutting means indicates that a deep ultraviolet laser having a wavelength of 266 nm is used, and “EB” indicates that an electron beam is used.

(Formation of write-once recording layer)
Dye A represented by the following chemical formula: 2 g was added and dissolved in 100 ml of 2,2,3,3-tetrafluoropropanol to prepare a dye-containing coating solution. And the prepared pigment | dye containing coating liquid was apply | coated on the conditions of 23 degreeC and 50% RH, changing the rotation speed to 300-4000 rpm by a spin coat method. Then, it was stored at 23 ° C. and 50% RH for 1 hour to form a write-once recording layer (thickness on groove: 170 nm, thickness on land: 120 nm).

  After the write-once recording layer was formed, annealing treatment was performed in a clean oven. The annealing treatment was performed by supporting the substrate on a vertical stack pole while leaving a gap with a spacer, and holding at 80 ° C. for 1 hour.

(Formation of light reflection layer)
An APC light reflecting layer (Ag: 98.1% by mass, Pd: 0) as a vacuum film-forming layer having a film thickness of 100 nm was formed on the write-once recording layer using a Cube manufactured by Unaxis, and DC sputtering in an Ar atmosphere. .9 mass%, Cu: 1.0 mass%) was formed. The film thickness of the light reflecting layer was adjusted by the sputtering time.

(Lamination of protective substrate)
On the light reflection layer, an ultraviolet curable resin (SD661, manufactured by Dainippon Ink) is applied by spin coating, and a protective substrate made of polycarbonate (same as the above substrate except that no pregroove is formed) is bonded. And cured by irradiating with ultraviolet rays.
The thickness of the adhesive layer made of the ultraviolet curable resin in the produced optical information recording medium was 25 μm.
Thus, optical information recording media of Examples 1 to 6 and Comparative Examples 1 and 2 were produced.

<Evaluation of optical information recording media>
(1) C / N (carrier-to-noise ratio) evaluation A recording / reproduction evaluation machine (manufactured by Pulstec Inc .: DDU1000) loaded with a 405 nm laser and NA 0.65 pickup was used for the produced optical information recording medium. A 0.2 μm signal (2T) was recorded and reproduced at 8 MHz and a linear velocity of 6.6 m / s, and C / N (after recording) was measured with a spectrum analyzer (Pulstech MSG2). This evaluation was performed using the optical information recording method of the present invention, and recording was performed on a groove. The recording power was 12 mW and the reproducing power was 0.5 mW. The results are shown in Table 1. Here, when the C / N (after recording) is 25 dB or more, the reproduction signal intensity is sufficient, which is practically preferable.

(2) Jitter Evaluation Using the recording / reproduction evaluation machine (Pulstec Corp .: DDU1000) loaded with a 405 nm laser and NA 0.65 pickup for the produced optical information recording medium, the clock frequency was 64.8 MHz, the linear velocity was 6.6 m / At s, a 0.2 μm signal (2T) was recorded and reproduced, and the C / N (after recording) was measured with a spectrum analyzer (Pulstech MSG2). This evaluation was performed using the optical information recording method of the present invention, and recording was performed on a groove. The recording power was 12 mW and the reproducing power was 0.5 mW. The results are shown in Table 1. Here, when the jitter is 19% or less, it means that it is practically preferable.

From the results shown in Table 1, the optical information recording media of Examples 1 to 6 (optical information recording media of the present invention) were evaluated using the optical information recording method of the present invention. The value was good.
On the other hand, the optical information recording medium of Comparative Example 1 has a problem of practical use because the wobble amplitude is too large and the C / N value is good, but the jitter value is large. Further, the optical information recording medium of Comparative Example 2 had a problem of practical use because the wobble amplitude was too small and the jitter value was good, but the C / N value was large.
Reference Examples 1 to 4 show that a deep ultraviolet laser (DUV) having a wavelength of 266 nm was used as the cutting means during mastering of the stamper. A pre-groove could not be formed.

It is a principal part schematic sectional drawing of the board | substrate showing the shape of the pre-groove.

Explanation of symbols

D Pre-groove groove depth W Pre-groove groove width θ Pre-groove groove width

Claims (2)

An optical information recording medium having a write-once recording layer containing a dye and a protective substrate having a thickness of 0.1 to 1.0 mm in this order on a substrate having a thickness of 0.1 to 1.0 mm,
Optical information recording characterized in that the pregroove formed on the substrate has a track pitch of 200 to 600 nm, a groove width of 50 to 300 nm, a groove depth of 30 to 200 nm, and a wobble amplitude of 10 to 50 nm. Medium. For an optical information recording medium having a write-once recording layer containing a dye and a protective substrate having a thickness of 0.1 to 1.0 mm in this order on a substrate having a thickness of 0.1 to 1.0 mm, An optical information recording method for performing recording by irradiating a laser beam having a wavelength of 100 to 600 nm from the substrate or the protective substrate side and forming pits in the write-once recording layer,
Optical information recording characterized in that the pregroove formed on the substrate has a track pitch of 200 to 600 nm, a groove width of 50 to 300 nm, a groove depth of 30 to 200 nm, and a wobble amplitude of 10 to 50 nm. Method.

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