JP2008041152A - Manufacturing method of optical recording medium stamper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium excellent in visibility of the images recorded on the label surface and a method of manufacturing an optical recording medium stamper to manufacture its base plate. <P>SOLUTION: An original stamper 56 is produced by electrocasting with 140-160 μm thick and made of nickel for instance. A resist 58 is applied to an end surface of this original stamper 56, and a photomask 60 is disposed preferably 5-200 μm apart from this resist 58. The resist 58 is partially removed in this state but remains in a shape of continuous curved hills 62 and dales 64, resulting in forming a preparatory wave surface. This preparatory wave surface is transferred to the master stamper and the resultant wave surface is transferred to an optical recording medium base plate to form a wave surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical recording medium stamper, and more particularly to a method for manufacturing an optical recording medium stamper for an optical recording medium having a label surface for laser recording.

  As one type of optical recording media such as CD-R and DVD-R, the content of electronic information recorded on the recording surface, such as a song title of music data, on the surface opposite to the recording surface on which electronic information is recorded In addition, there is known a label on which visible information such as a title for identifying recorded data is printed. For this reason, the opposite surface is called a label surface.

  This type of optical recording medium is manufactured by printing a title or the like in advance on a circular label sheet with a printer or the like and sticking the label sheet on a label surface.

  However, when the label sheet is attached to the label surface, a printer for printing the label sheet is required separately from the disk drive. That is, after recording on the recording surface of an optical recording medium using a disk drive, it is necessary to perform complicated operations such as taking out the optical recording medium from the disk drive and further attaching a label sheet printed by a printer. There is.

  In view of this, an optical recording medium has been proposed in which a laser marker is used on the label surface and display can be performed by changing the contrast between the surface and the background (see, for example, Patent Document 1). By using this optical recording medium, recording on the recording surface and desired visible image recording on the label surface can be performed only by the optical recording medium drive. Accordingly, it is not necessary to separately prepare a printer or the like, and the complicated work of attaching a label sheet is also unnecessary.

JP-A-11-66617

  For example, when the visible image recording layer is formed on the other substrate on which the grooves are regularly formed in the same manner as the surface of the one substrate on which the recording layer of DVD-R is formed, against the light from the outside When the groove acts like a diffraction grating, strong interference occurs, and the visibility of the recorded visible image is poor.

  Although it is conceived that the substrate is roughened to improve the visibility, in this case, the light incident on the label surface is difficult to scatter, and thus directivity is generated in the visibility. That is, although the visibility is good from one direction, it is not easy to visually recognize the visible image from another direction.

  As described above, when desired visible image recording is performed on the label surface, further improvement in the visibility of the recorded visible image information is desired.

  A general object of the present invention is to provide a method of manufacturing a stamper for an optical recording medium capable of forming a visible image with good visibility on the optical recording medium.

  The object of the present invention is preferably achieved by the following configurations.

[1] A method of manufacturing a stamper for an optical recording medium, wherein a wave-shaped portion having a curved top portion and a bottom portion is provided on an end surface for roughening a substrate constituting the optical recording medium,
Applying a resist to a master stamper having a thickness of 140 to 160 μm provided by electroforming;
Irradiating light to the resist through the photomask after disposing a photomask away from the resist, and providing a preliminary wave-like portion that is continuous at the top and bottom of the resist; and
A step of providing a second plate stamper provided with a corrugated portion to which the shape of the preliminary corrugated portion is transferred by electroforming using the original stamper provided with the preliminary corrugated portion;
A method for manufacturing a stamper for an optical recording medium.

[2] The method for manufacturing a stamper for an optical recording medium according to [1], wherein a distance between the resist and the photomask is set to 5 to 200 μm.

[3] The optical recording according to [1] or [2], further including a step of providing a third plate stamper having a reverse wave-like portion to which the shape of the wave-like portion is transferred by electroforming using the second plate stamper. A method for manufacturing a medium stamper.

[4] The stamper for an optical recording medium according to [3], further comprising a step of providing a fourth plate stamper including a forward wave-like portion to which the shape of the reverse wave-like portion is transferred by electroforming using the third plate stamper. Manufacturing method.

[5] Any one of [1] to [4], wherein the original stamper is provided with a pit portion provided with a concave portion or a convex portion on one end surface, and the preliminary wave portion is provided on the one end surface. A manufacturing method of the stamper for optical recording media described in 2.

  According to the present invention, since the master stamper is manufactured using the original stamper having a thickness of 140 to 160 μm provided by electroforming, the time required for electroforming to manufacture the original stamper, and thus the master stamper Time to get is reduced.

  Further, as the thickness of the original stamper is reduced, the surface roughness of the end face of the original stamper is reduced and becomes relatively smooth. Accordingly, the distance between the resist applied to the original stamper and the photomask disposed above the resist is substantially constant regardless of the resist portion. Can be formed.

  By using a master stamper having a reverse wave portion or a forward wave portion to which the shape of the preliminary wave portion is transferred, a substrate having a wave portion having substantially the same altitude is obtained. In an optical recording medium configured using this substrate, the incident light from the substrate side is easily scattered, so that the visibility of a visible image from an unspecified direction can be improved.

  Preferred embodiments of the method for manufacturing an optical recording medium stamper according to the present invention will now be described in detail with reference to the accompanying drawings.

[Optical recording medium and manufacturing method thereof]
The optical recording medium according to the present embodiment can record information by irradiating laser light from one end surface side, and can perform desired visible image recording by irradiating laser light from the other end surface side. Is possible. That is, this optical recording medium has at least an information recording layer and an image recording layer in this order on a first substrate, and has a second substrate on the image recording layer. A third substrate may exist between the information recording layer and the image recording layer.

  In this optical recording medium, the end surface facing the image recording layer side of the second substrate is roughened. More specifically, the end surface (hereinafter also referred to as “roughened surface”) is provided with a wave-like portion in which the top portion and the bottom portion are curved and connected. As will be described later, the corrugated portion is formed by transferring the shape of the corrugated portion provided in the optical recording medium stamper to the second substrate.

  As for the roughness of the wavy portion, the maximum height (Rz) is preferably 0.1 to 5 μm, and the average length (RSm) of the roughness curve elements is preferably 1 to 500 μm. By being in this range, visibility can be particularly improved.

  The wavy portion may be provided on the entire roughened surface, but is preferably formed in a region from 24 to 58.5 mm from the center. Even if a roughened surface is provided in an area of less than 24 mm, an optical pickup is difficult to enter in an area of less than 24 mm, so even if a wavy portion is provided, it does not contribute much to the improvement of visibility. On the other hand, if the wavy portion is provided in the region exceeding 58.5 mm, it tends to be difficult to clean the edge portion of the image recording layer.

  As this type of optical recording medium, first, there is a DVD type configuration (including DVD-R, HD-DVD, etc.). That is, this is a so-called bonded type structure in which the first substrate on which the information recording layer is formed and the second substrate on which the image recording layer is formed are bonded together via an adhesive layer.

  Furthermore, the optical recording medium according to the present embodiment can be configured as a Blu-ray disc (BD).

  FIG. 1 illustrates a schematic cross-sectional view of the optical recording medium according to the present embodiment.

  As shown in FIG. 1, the optical disc 10 includes a first laminated body 12 and a second laminated body 14. The first laminated body 12 includes a transparent first substrate 16, an information recording layer 18 formed on the first substrate 16, and a first reflective layer 20 formed on the information recording layer 18. . The second laminate 14 includes a transparent second substrate 22, an image recording layer 24 formed on the second substrate 22, and a second reflective layer 26 formed on the image recording layer 24. . And the 1st laminated body 12 and the 2nd laminated body 14 are bonded together through the contact bonding layer 28 so that the 1st reflective layer 20 and the 2nd reflective layer 26 may oppose. In the optical disc 10, the surface of the second substrate 22 facing the image recording layer 24 is roughened.

  The information recording layer 18 can record and / or reproduce data (pit information) by, for example, laser light irradiated from the first substrate 16 side.

  The image recording layer 24 can record a visible image by, for example, laser light emitted from the second substrate 22 side.

  Further, in this optical disc 10, a prepit area 30 is assigned to a part of the surface of the second substrate 22 (the surface on the side where the image recording layer 24 is formed), and one or more prepits 32, preferably A plurality of pre-pits 32 are formed.

  As the information indicated by the combination of the pre-pits 32, various types of information regarding the optical disc 10 are conceivable. For example, identification information as to whether the optical disc 10 is an optical disc having the image recording layer 24 or a visible image on the image recording layer 24 is considered. Information on the output of the laser beam when drawing the image, information on the spot diameter, information on the gradation of the visible image to be drawn, and the like. Therefore, it is possible to easily detect whether the optical disc 10 is the optical disc 10 having the image recording layer 24 by detecting the pre-pit 32, and it is optimal for drawing a visible image on the image recording layer 24. It is possible to draw with a laser output, and to record a visible image with high drawing characteristics. In addition, the information shown by the combination of the prepits 32 includes manufacturer information and the like.

  In the surface of the second substrate 22, the allocation position of the prepit area 30 is not particularly limited. For example, as shown in the optical disc 10a according to the first modification of FIG. 3, even if the prepit region 30 is located on the inner peripheral side of the region where the image recording layer 24 is formed (image recording layer forming region 34). Good. Since the pre-pit region 30 is on the inner peripheral side, the pre-pit 32 is not filled with the dye compound, so that there is an advantage that the return light from the pre-pit 32 can be easily detected. However, in order not to form the image recording layer 24 in the prepit area 30, a certain margin is required between the outermost periphery of the prepit area 30 and the innermost periphery of the image recording layer forming area 34.

  Of course, from the viewpoint of securing the image recording layer forming region 34 as wide as possible, the prepit region 30 and the image recording layer forming region 34 may partially overlap as shown in FIG. That is, at least a part of the image recording layer 24 may be formed on the prepit 32.

  As shown in FIGS. 1 and 3, when the prepit region 30 is provided on the inner peripheral side of the second substrate 22, it is preferable to provide the prepit region 30 within a radius of 21 to 24 mm from the center of the second substrate 22.

  As shown in FIG. 2, the average depth hp of the prepits 32 is 150 to 400 nm, and preferably 200 to 300 nm. By setting the thickness to 150 to 400 nm, the signal amplitude of a signal (referred to as a return light signal) after the return light from the prepit 32 is converted into an electrical signal is increased, and the reading accuracy of the return light signal can be increased. Moreover, a return optical signal can be more reliably detected by setting it as 200-300 nm.

  The average half width W in the radial direction of the pre-pits 32 is preferably 200 to 500 nm, and more preferably 250 to 450 nm. By setting the thickness to 200 to 500 nm, the crosstalk in the track-to-track direction superimposed on the return optical signal is small, and a signal amplitude sufficient for detection can be obtained. Note that the circumferential length (half width) of the pre-pit 32 depends on the information to be recorded, and is thus set as appropriate.

  The ratio (h1 / h2) between the average thickness h1 of the image recording layer 24 on the convex portion 32A of the prepit 32 and the average thickness h2 of the image recording layer 24 on the concave portion 32B of the prepit 32 is 0.1-0. It is preferable that the depth (hp + h1-h2) of the depression of the image recording layer 24 on the recess 32B of the prepit 32 is 70 to 250 nm.

  When “h1 / h2” and “hp + h1−h2” are in the above ranges, the surface on which the second reflective layer 26 of the image recording layer 24 is formed has moderate irregularities for reading laser light. A good reproduction signal can be obtained. A more preferable range of “h1 / h2” is 0.2 to 0.8. A more preferable range of “hp + h1−h2” is 100 to 200 nm, and more preferably 120 to 180 nm.

  Further, as shown in FIG. 2, it is preferable that the second reflective layer 26 is formed along the image recording layer 24, and the average thickness t1 of the second reflective layer 26 on the convex portion 32A of the prepit 32 and the prepit The ratio (t1 / t2) to the average thickness t2 of the second reflective layer 26 on the 32 concave portions 32B is preferably 0.8 to 1.2, more preferably 0.9 to 1.1. preferable.

  The hp, h1, h2, etc. can be obtained from AFM, transmission spectrum or ellipsometer. As another method, it can be obtained by observing a cross section of the completed optical disc 10 with an SEM or the like.

  The second substrate 22 having the pre-pits 32 as described above can be manufactured using an optical recording medium stamper (hereinafter also simply referred to as a stamper). In order to form the prepit 32, the stamper is provided with a prepit portion in which concave portions and convex portions are alternately arranged. It is preferable that the average height of the convex portion among the concave portion and the convex portion is 150 to 400 nm. By using a stamper, the above-described optical disk can be manufactured efficiently.

  The configuration of the optical disc described above is not particularly limited as long as the configuration includes the image recording layer 24 capable of drawing a visible image by laser light irradiation and the prepit region 30 having one or more prepits 32. That is, it can be any of a read-only type, a write-once type, a rewritable type, and the like. Of these, the write-once type is preferable. The recording format is not particularly limited, such as a phase change type, a magneto-optical type, and a dye type. Among these, a pigment type is preferable.

  In particular, the optical disc 10 shown in FIG. 1 has an information recording layer 18 on a first substrate 16 and an image recording layer 24 on a second substrate 22, and these are bonded together. It is preferable to apply to a configuration of DVD (including DVD-R, DVD-RW, HD DVD, etc. in addition to DVD).

  As a layer configuration of the optical disc 10, in addition to the layer configuration shown in FIG.

  (1) Although the first layer configuration is not shown, the information recording layer 18, the first reflective layer 20, and the adhesive layer 28 are sequentially formed on the first substrate 16, and the image recording layer 24 is formed on the adhesive layer 28. This is a configuration in which the second substrate 22 having the above is bonded.

  (2) Although the second layer configuration is not shown, the information recording layer 18, the first reflective layer 20, the protective layer, and the adhesive layer 28 are sequentially formed on the first substrate 16, and the image is formed on the adhesive layer 28. The second substrate 22 having the recording layer 24 is bonded.

  (3) Although the third layer configuration is not shown, the information recording layer 18, the first reflective layer 20, the first protective layer, the adhesive layer 28, and the second protective layer are sequentially formed on the first substrate 16, The second substrate 22 having the image recording layer 24 is bonded onto the second protective layer.

  (4) Although the fourth layer configuration is not shown, the information recording layer 18, the first reflective layer 20, the first protective layer, the adhesive layer 28, the second protective layer, and the third protective layer are formed on the first substrate 16. Are sequentially formed, and the second substrate 22 having the image recording layer 24 is bonded onto the third protective layer.

  (5) In the fifth layer configuration, the information recording layer 18, the first reflective layer 20, the adhesive layer 28, and the second reflective layer 26 are sequentially formed on the first substrate 16, and the second reflective layer 26 is formed on the second reflective layer 26. In this configuration, the second substrate 22 having the image recording layer 24 is bonded. This layer structure is substantially the same as in FIG.

  (6) Although the sixth layer configuration is not shown, the information recording layer 18, the first reflective layer 20, and the first protective layer are sequentially formed on the first substrate 16, while the image is formed on the second substrate 22. The recording layer 24, the second reflective layer 26, and the second protective layer are sequentially formed, and the first protective layer and the second protective layer are bonded together via the adhesive layer 28.

  Note that the layer configuration shown in FIG. 1 and the layer configurations (1) to (6) described above are merely examples, and these layer configurations are not limited to the order described above, and may be partially replaced. A part (except for the image recording layer 24) may be omitted. Furthermore, each layer may be composed of one layer or a plurality of layers.

  When optical information is recorded on an optical recording medium or when recorded information is reproduced, a predetermined wavelength from the first substrate 16 side (650 to 670 nm for DVD-R, HD-DVD) Is irradiated with a laser beam of 400 to 410 nm or less.

  When a visible image is recorded on the image recording layer 24, a predetermined laser beam (for example, a laser beam having a linear velocity of 3.5 m / s, a wavelength of 660 nm, NA = 0.6, and a disk surface of 10 mW from the second substrate 22 side). ), The irradiated portion is altered and the contrast is changed, and a visible image can be formed.

  As described above, since an image can be formed by laser light, a desired image can be efficiently recorded on the label surface (image recording surface) of the optical recording medium by the optical recording medium drive without separately preparing a printer or the like. be able to. Moreover, since the surface of the second substrate 22 on the image recording layer side is roughened, the visibility of the visible image can be improved.

  The “second substrate” in the present invention may include a cover layer and a transparent sheet in addition to the substrate provided on the opposite side of the first substrate with the information recording layer or the like interposed therebetween. Therefore, as another configuration of the optical recording medium according to the present embodiment, a CD-type configuration (including a CD-R) in which an information recording layer, an image recording layer, and a cover layer are formed in this order on a substrate. It can also be.

  In the case of a CD type configuration, an information recording layer, a reflective layer, a protective layer, a reflective layer, and an image recording layer are formed in this order on the first substrate, and a roughened cover layer is formed on the image recording layer. It becomes the formed structure. Even in such a configuration, since the surface of the cover layer on the image recording layer side is roughened, the visibility of the visible image can be improved.

  When optical information is recorded on the optical recording medium or when recorded information is reproduced, laser light having a predetermined wavelength (for example, about 660 nm) is irradiated from the first substrate side.

  When a visible image is recorded on the image recording layer, a visible image can be obtained by irradiating the above-mentioned predetermined amount of laser light from the cover layer (second substrate) side, altering the irradiated portion and changing the contrast. Can be formed.

  Thus, even with a CD-type optical recording medium, an image can be formed by laser light. Therefore, a desired image can be efficiently recorded on the label surface (image recording surface) of the optical recording medium by the optical recording medium drive without separately preparing a printer or the like. Further, since the surface of the second substrate on the image recording layer side is roughened, the visibility of the visible image can be improved.

  Among the optical recording media described above, the DVD-type optical recording medium shown in FIG. 1 can be manufactured as described below. That is, a roughening step of roughening the surface on the side of the second substrate on which the image recording layer is formed using a stamper for an optical recording medium provided with a wavy portion to be described later; An image recording layer forming step of forming the image recording layer on the roughened surface side, an information recording layer forming step of forming the information recording layer on the first substrate, the first substrate, and the The second substrate is manufactured through a bonding step in which the information recording layer and the image recording layer are bonded to each other.

  If necessary, in the information recording layer forming step and the image recording layer forming step, a process for forming a reflective layer and a protective layer may be performed.

  On the other hand, in the case of a CD-type optical recording medium, at least an information recording layer, an image recording layer, and a cover layer (second substrate) having a roughened surface are formed on a first substrate. be able to.

  Note that the layer configuration shown in FIG. 1 and the layer configurations (1) to (6) described above are merely examples, and these layer configurations are not limited to the order described above, and may be partially replaced. A part (except for the image recording layer 24) may be omitted. Furthermore, each layer may be composed of one layer or a plurality of layers.

  In the following, each layer of the optical disc 10 and a method for forming the layer will be described with reference to the layer configuration shown in FIG.

  The board | substrate and each layer which were shown by the said manufacturing method are demonstrated in detail.

(Information recording layer 18)
The information recording layer 18 is a layer where information is recorded and reproduced by a laser beam used for recording and reproduction. In particular, code information (coded information) such as digital information is recorded. The recording layer may be a dye recording layer or a phase change recording layer, but a dye recording layer is preferred.

  Specific examples of dyes contained in the information recording layer 18 include cyanine dyes, oxonol dyes, azo dyes, phthalocyanine dyes, triazole compounds (including benzotriazole compounds), triazine compounds, merocyanine compounds, aminobutadiene compounds, and cinnamic acid compounds. , Benzoxazole compounds, pyromethene compounds, squarylium compounds, and the like. In addition, these may have a metal atom in the coordination center.

  JP-A-4-74690, JP-A-8-127174, JP-A-11-53758, JP-A-11-334204, JP-A-11-334205, JP-A-11-334206, It is also possible to use dyes described in JP-A-11-334207, JP-A-2000-43423, JP-A-2000-108513, JP-A-2000-158818, and the like.

  Among the above compounds, when the optical recording medium is “CD-R”, cyanine dyes, azo dyes, and phthalocyanine dyes are preferable. When “DVD-R” is used, cyanine dyes, oxonol dyes, azo dyes (Ni, Co complexes) In the case of “Blu-ray Disc and HD-DVD”, cyanine dyes, oxonol dyes, azo dyes, phthalocyanine dyes, benzotriazole compounds, and triazine compounds are preferred.

  In the case of “CD-R”, cyanine dyes, azo dyes, and phthalocyanine dyes are more preferable. In the case of “DVD-R”, cyanine dyes, oxonol dyes, and azo dyes (including Ni and Co complexes) are more preferable. In the case of “Blu-ray Disc and HD-DVD”, cyanine dyes, oxonol dyes, azo dyes, and phthalocyanine dyes are more preferable.

  The information recording layer 18 is prepared by dissolving a recording substance such as a dye in a suitable solvent together with a binder or the like to prepare a coating solution, and then coating the coating solution on the first substrate to form a coating film. It is formed by drying. The concentration of the recording substance 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, and most preferably. Is in the range of 0.5-3 mass%.

  The information recording layer 18 can be formed by a method such as vapor deposition, sputtering, CVD, or solvent coating, but solvent coating is preferred. In this case, a coating solution is prepared by dissolving a quencher, a binder, and the like in a solvent in addition to the above-described pigment, and then coating the coating solution on the substrate surface to form a coating film, followed by drying. Can be done.

  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 Amide; Hydrocarbon such as methylcyclohexane; Ether such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane; Alcohol such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; 2,2,3,3-tetra Fluorinated solvents such as fluoropropanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether And the like can be given.

  The above solvents can be used alone or in combination of two or more in consideration of the solubility of the dye used. Various additives such as antioxidants, UV absorbers, plasticizers, and lubricants may be further added to the coating solution depending on the purpose.

  When a binder is used, examples of the binder include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene and polyisobutylene; Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer; acrylic resins such as polymethyl acrylate and polymethyl methacrylate; polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin, Examples include synthetic organic polymers such as rubber derivatives and initial condensates of thermosetting resins such as phenol / formaldehyde resins.

  When a binder is used in combination as the material of the information recording layer 18, the amount of the binder used is generally in the range of 0.01 to 50 times the mass of the dye, preferably 0.1 to 5 times. In the range of quantities.

  Examples of the method for applying the solvent 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. The information recording layer 18 may be a single layer or a multilayer. The thickness of the information recording layer 18 is generally in the range of 10 to 500 nm, preferably in the range of 15 to 300 nm, and more preferably in the range of 20 to 150 nm.

  The information recording layer 18 can contain various anti-fading agents in order to improve the light resistance of the information recording layer 18. As the anti-fading 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-58-175893, JP-A-59-31194, JP-A-60-18387, JP-A-60-19586, and JP-A-60-19587. JP-A-60-35054, JP-A-60-36190, JP-A-60-36191, JP-A-60-44554, JP-A-60-44555, JP-A-60 -44389, JP-A-60-44390, JP-A-60-54892, JP-A-60-47069, JP-A 63-209995, JP-A-4-25492, JPB-1 No. -38680, and Japanese Patent Publication No. 6-26028, German Patent No. 350399, and the Chemical Society of Japan, October 1992, page 1141, etc. Kill.

  The amount of the anti-fading agent such as the singlet oxygen quencher used is usually in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 45% by mass, more preferably , In the range of 3 to 40% by mass, particularly preferably in the range of 5 to 25% by mass.

  When the information recording layer 18 is a phase change type, the information recording layer 18 is made of a phase change type optical recording material composed of at least Ag, Al, In, Te, and Sb that can take at least two states of a crystalline state and an amorphous state. Is preferred. Specific examples of this type of optical recording material include Sb—Te alloy, Ge—Sb—Te alloy, Pd—Ge—Sb—Te alloy, Nb—Ge—Sb—Te alloy, Pd—Nb—Ge—Sb— Te alloy, Pt—Ge—Sb—Te alloy, Co—Ge—Sb—Te alloy, In—Sb—Te alloy, Ag—In—Sb—Te alloy, Ag—V—In—Sb—Te alloy, Ag— Ge-In-Sb-Te alloy, etc. are mentioned. Among these, Ge—Sb—Te alloy and Ag—In—Sb—Te alloy are preferable because they can be rewritten many times. The layer thickness of the phase change information recording layer 18 is preferably 10 to 50 nm, and more preferably 15 to 30 nm.

  The phase change type information recording layer 18 can be formed by a vapor phase thin film deposition method such as a sputtering method or a vacuum evaporation method. If necessary, a known dielectric layer may be formed on the information recording layer 18.

(Image recording layer 24)
As described above, the optical disc 10 has the image recording layer 24 at a position closer to the second substrate 22 (including the cover layer) than the information recording layer 18. The image recording layer 24 records visible images (visible information) desired by the user, such as characters, graphics, and patterns. Here, the visible image means a visually recognizable image and includes all visually recognizable information such as characters (columns), designs, figures and the like.

  Visible images recorded on the image recording layer 24 include visible images desired by the user, such as characters, graphics, and patterns. Specifically, the disc title, content information, content thumbnails, related images, Examples include design patterns, copyright information, recording date and time, recording method, recording format, and barcode.

  Also, as character information, usable person designation information, use period designation information, usable number designation information, rental information, resolution designation information, layer designation information, user designation information, copyright holder information, copyright number information, manufacturing Information, manufacturer date information, sale date information, dealer or seller information, use set number information, region designation information, language designation information, application designation information, product user information, use number information, and the like.

  The image recording layer 24 only needs to be able to record image information such as characters, images, and patterns in a visible manner by laser light irradiation. Considering that a visible image can be clearly formed by laser light irradiation, the image recording layer 24 preferably contains a dye compound. As the constituent material, the dye described in the information recording layer 18 described above can be suitably used. In this case, in consideration of cost and the like, the image recording layer 24 is preferably formed by spin coating using a coating liquid containing a dye compound.

  Further, in the optical disc 10, the constituent component (dye or phase change recording material) of the information recording layer 18 described above and the constituent component of the image recording layer 24 may be the same or different. Since the required properties of the layer 18 and the image recording layer 24 are different, it is preferable to make the constituent components different. Specifically, the constituent components of the information recording layer 18 are preferably excellent in recording / reproducing characteristics, and the constituent components of the image recording layer 24 are preferably those in which the contrast of the recorded image is high. In particular, when a dye is used, it is preferable to use a cyanine dye, a phthalocyanine dye, an azo dye, an azo metal complex, or an oxonol dye among the dyes described above from the viewpoint of improving the contrast of a recorded image in the image recording layer 24. .

  A leuco dye can also be used. Specifically, crystal violet lactone; 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl 2- Phthalide compounds such as methylindol-3-yl) -4-azaphthalide; 3-cyclohexylmethylamino-6-methyl-7-anilinofluorane, 2- (2-chloroanilino) -6-dibutylaminofluorane, 3- Diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 2- (2-chloroanilino) -6-diethylaminofluorane, 2-anilino-3-methyl- 6 (N-ethylisopentylamino) fluorane, 3-diethylamino-6-chloro-7-anilinofluor Down, 3-benzyl-ethyl-6-methyl-7-anilinofluoran, 3-methyl-propylamino-6-methyl-7-anilinofluoran fluoran compounds such Oran; and the like are preferable.

  The image recording layer 24 can be formed by preparing a coating solution by dissolving the above-described dye in a solvent and coating the coating solution. As the solvent, the same solvent as that used for preparing the coating solution for the information recording layer 18 described above can be used. Other additives, coating methods, and the like are the same as those for the information recording layer described above.

  The layer thickness of the image recording layer 24 is preferably 0.01 to 50 μm, more preferably 0.02 to 20 μm, and further preferably 0.03 to 5 μm.

  The image recording layer 24 is a layer in which visible light is recorded by irradiating a laser beam with a predetermined power a plurality of times on a substantially identical locus, or a laser beam with a predetermined power is swung in the radial direction of the optical recording medium, and The layer is preferably a layer in which visible information is recorded by being irradiated a plurality of times on substantially the same locus.

(First substrate 16)
The first substrate 16 can be arbitrarily selected from various materials used as a substrate of a conventional optical recording medium.

  Examples of substrate materials include acrylic resins such as glass, polycarbonate, and polymethyl methacrylate, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, amorphous polyolefins, and polyesters. You may use them together. These materials can be used as a film or as a rigid substrate. Among the above materials, polycarbonate is preferable from the viewpoints of moisture resistance, dimensional stability, price, and the like.

  The thickness of the first substrate 16 is preferably 0.05 to 1.2 mm, and more preferably 0.1 to 1.1 mm.

  The first substrate 16 is provided with irregularities (pregrooves) representing information such as tracking guide grooves or address signals.

  In the case of DVD-R or DVD-RW, the pregroove track pitch is preferably in the range of 300 to 900 nm, more preferably 350 to 850 nm, and even more preferably 400 to 800 nm.

  The depth of the pregroove (groove depth) is preferably in the range of 100 to 160 nm, more preferably 120 to 150 nm, and still more preferably 130 to 140 nm. Furthermore, the groove width (half width) of the pregroove is preferably in the range of 200 to 400 nm, more preferably 230 to 380 nm, and further preferably 250 to 350 nm.

  On the other hand, in order to achieve a higher recording density, a substrate on which a groove having a narrower track pitch than that of a conventional DVD-R or the like may be used. In this case, the groove track pitch is preferably in the range of 280 to 450 μm, more preferably in the range of 300 to 420 nm, and still more preferably 320 to 400 nm. Further, the depth of the groove (groove depth) is preferably in the range of 15 to 150 nm, and more preferably in the range of 25 to 100 nm. Further, the groove width of the groove is preferably in the range of 50 to 250 nm, and more preferably in the range of 100 to 200 nm.

  In the case of CD-R or the like, the groove track pitch is preferably in the range of 1.2 to 2.0 μm, more preferably 1.4 to 1.8 μm, and more preferably 1.55 to 1.65 μm. More preferably. The groove depth (groove depth) is preferably in the range of 100 to 250 nm, more preferably 150 to 230 nm, and even more preferably 170 to 210 nm. The groove width of the pregroove is preferably in the range of 400 to 650 nm, more preferably 480 to 600 nm, and further preferably 500 to 580 nm.

  On the surface side of the first substrate 16 on the side where the information recording layer 18 is provided (the surface side on which the grooves are formed), an undercoat layer is provided for the purpose of improving the flatness, improving the adhesive force and preventing the recording layer from deteriorating. May be provided.

  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, chlorosulfonated. High molecular substances such as polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, and silane coupling agents And the like. The undercoat layer is formed by dissolving or dispersing the above substances in a suitable 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, preferably in the range of 0.01 to 10 μm.

(Reflective layer)
For the purpose of improving reflectivity during information reproduction, it is preferable that a reflective layer is provided adjacent to the information recording layer 18 and / or the image recording layer 24. As the light reflective material as the material of the reflective layer, it is preferable to use a material having a high reflectance with respect to laser light. Examples include 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, stainless steel, and semiconductor materials. These substances may be used alone or in combination of two or more or as an alloy.

  Among these materials, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred are Au metal, Ag metal, Al metal or alloys thereof, and most preferred are Ag alloys (Ag—Nd—Cu and Ag—Pd—Cu).

  The reflective layer can be formed on the substrate or the recording layer, for example, by vapor deposition, sputtering or ion plating of the light reflective material. The thickness of the reflective layer is generally in the range of 10 to 300 nm and preferably in the range of 50 to 200 nm.

(Adhesive layer)
The adhesive layer is provided in order to bond and laminate the stacked bodies or the stacked body including the first substrate and the second substrate when a bonded optical recording medium such as a DVD is manufactured. 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 SD-640 and SD-661 manufactured by Dainippon Ink and Chemicals, Inc., and SK6100, SK6300, and SK6400 manufactured by Sony Chemical Corporation. The thickness of the adhesive layer is preferably in the range of 1 to 100 μm, more preferably in the range of 5 to 60 μm, and particularly preferably in the range of 20 to 55 μm in order to give elasticity.

(Protective layer)
The protective layer is an arbitrary layer provided in order to prevent moisture from entering and scratching. The material constituting the protective layer is preferably an ultraviolet curable resin, a visible light curable resin, a thermosetting resin, silicon dioxide, or the like, and more preferably an ultraviolet curable resin. Examples of the ultraviolet curable resin include ultraviolet curable resins such as “SD-640” manufactured by Dainippon Ink and Chemicals, Inc. Further, SD-347 (manufactured by Dainippon Ink and Chemicals), SD-694 (manufactured by Dainippon Ink and Chemicals), SKCD1051 (manufactured by SKC) and the like can be used. The thickness of the protective layer is preferably in the range of 1 to 200 μm, and more preferably in the range of 50 to 150 μm.

(Second substrate 22)
The second substrate 22 (also referred to as a dummy substrate or a protective substrate) having a roughened surface is provided to face the first substrate in the case of a bonded optical recording medium. As the material, the same material as that of the first substrate described above can be used. Similarly to the first substrate, no groove is required on the surface side on which the image recording layer is formed. The thickness of the second substrate is preferably 0.05 to 1.2 mm, more preferably 0.1 to 1.1 mm, and still more preferably 0.5 to 0.7 mm.

  As a roughening method in the step (roughening step) for roughening the surface of the second substrate 22 on which the image recording layer 24 is formed, a method using a stamper may be mentioned.

  In this roughening treatment, a surface on which the image recording layer is formed of the second substrate 22 is roughened using a stamper that has been subjected to the roughening treatment on one surface with which the second substrate 22 contacts. It is to become. Specifically, first, a stamper having a corrugated portion is produced as a stamper used when the second substrate 22 is produced (described later). Then, this stamper is placed on the mold so that the surface where the wavy portion exists is in contact with the resin material of the second substrate 22, and is molded by a known method so that the roughened surface is formed only on one surface. The 2nd board | substrate 22 which has is produced.

  Here, the roughened surface is provided with the pre-pits 32 by forming concave portions or convex portions.

  In the case where the second substrate 22 is a cover layer, the cover layer is generally provided for the purpose of physically and chemically protecting the information recording layer 18, the image recording layer 24, and the like. Then, in addition to the above purpose, the visibility of the visible image is improved by roughening the cover layer on the image recording layer 24 side. The thickness of the cover layer is preferably in the range of 10 nm to 5 μm.

  Further, a transparent sheet made of polycarbonate or cellulose triacetate may be used as the cover layer. In this case, the thickness of the transparent sheet is preferably 0.01 to 0.2 mm. As the roughening treatment on the image recording layer side of the transparent sheet, it is preferable to apply the roughening treatment using the stamper described above.

  As described above, the second substrate 22 roughened as described above is used as a substrate of the optical disc 10 on which at least the information recording layer 18 and the image recording layer 24 are formed in this order on one surface. The

  In addition to the optical disk 10, the second substrate 22 includes the image recording layer 24 and can be used as an optical member that can form an image on the image recording layer 24 with light. That is, this optical member is configured by forming at least an image recording layer on the roughened surface of the substrate. Examples of such an optical member include a seal.

  In the optical recording medium according to the present embodiment, the surface on the image recording layer side of the intermediate layer formed adjacent to the second substrate may be roughened to form a roughened surface. When the surface of the intermediate layer on the image recording layer side is roughened, the roughened surface is not necessarily provided on the second substrate. As such an intermediate layer, there is a protective layer, for example, a protective layer composed of a UV curable resin.

  As described above, the optical recording medium according to the present embodiment has a layer (particularly, the second substrate 22) that is roughened by forming a wave-like portion. In this wavy portion, incident light is easily scattered as compared with the case where the surface is roughened by a concave portion and a convex portion whose corners are angular. For this reason, the visible image recorded on the label surface can be easily viewed from an unspecified direction.

[Substrate and manufacturing method thereof]
As can be understood from the above description, the optical recording medium substrate according to the present embodiment is subjected to a roughening treatment on at least one surface to form a corrugated portion. That is, the second substrate 22 constituting the optical disc 10 corresponds to this optical recording medium substrate.

  As will be described later, this optical recording medium substrate can be manufactured by transferring a wave-like portion provided on a stamper.

[Stamper and manufacturing method thereof]
As shown in FIG. 4, the stamper 40 according to the present embodiment is a master stamper used when producing a substrate for an optical recording medium (second substrate 22) provided with a wave-shaped portion, and from one end surface. A pre-pit 46 formed by a plurality of protruding convex portions 42 and a wave-like portion 52 that is depressed from the one end surface and has a curved top portion 48 and a bottom portion 50 are formed on the same surface. That is, the one end surface of the master stamper 40 is subjected to a roughening process by providing a wave-like portion 52.

  The master stamper 40 can be manufactured as follows.

  First, as shown in FIG. 5, an original stamper 56 provided with a pit forming portion 54 at a position corresponding to the prepit 46 is prepared. The original stamper 56 is a Ni disk-shaped body manufactured by nickel electroforming. FIG. 5 shows only the vicinity of the central portion, and the same applies to the following.

  Here, the thickness of the original stamper 56 is conventionally set to about 300 μm, but is set to 140 to 160 μm in the present embodiment. Thereby, the time required for the nickel electroforming for producing the original stamper 56 is shortened. Further, as the thickness is reduced, the flatness of the original stamper 56 is improved.

  Next, a resist 58 is applied to one end surface (roughened surface forming surface) of the Ni original stamper 56 as shown in FIG. A thickness of about 0.3 to 2 μm is sufficient for the resist 58.

  The upper end surface of the resist 58 is also relatively smooth. This is because, as described above, the roughened surface forming surface of the original stamper 56 is relatively smooth and there are very few depressions or bumps, so that the resist 58 is unlikely to be depressed or raised.

  Next, a photomask 60 is provided apart from the resist 58. On the photomask 60, patterns such as a lattice shape and a honeycomb shape are periodically formed (for example, 1 μm or more). Of course, an irregular pattern may be used.

  Thereafter, a part of the resist 58 is irradiated through the photomask 60, and further development, rinsing and the like are performed.

  By this removal step, as shown in FIG. 7, the resist 58 remains in a shape in which the top portion 62 and the bottom portion 64 are curved and connected. That is, the resist 58 remaining in such a shape forms a preliminary corrugated portion 66 having a top portion 62 raised from the roughened surface forming surface.

  In this way, by performing light irradiation or the like while the photomask 60 is separated from the resist 58, the preliminary corrugated portion 66 (roughened surface forming surface) having a curved surface can be formed on the original stamper 56. That is, in this case, it is possible to avoid the formation of a convex portion with a corner that is angular on the roughened surface forming surface.

  The distance between the resist 58 and the photomask 60 is preferably 5 to 200 μm. If it is less than 5 μm, it becomes difficult to form the preliminary corrugated portion 66. On the other hand, if it exceeds 200 μm, it is not easy to set the top of the preliminary corrugated portion 66 to a predetermined height. The most preferable separation distance is 50 to 100 μm.

  During the removal process, for example, during light irradiation or development, the original stamper 56 is held by being sucked. Since the thickness of the original stamper 56 is about 140 to 160 μm, the original stamper 56 exhibits good elasticity. Therefore, even if there is an upward warp in the vicinity of the outer peripheral surface of the original stamper 56, for example, The warp is drawn downward by suction during suction holding. That is, the original stamper 56 is smoothed.

  Moreover, as described above, the upper end surface of the resist 58 is substantially smooth. Therefore, if the photomask 60 is arranged substantially in parallel on the resist 58, the distance from the photomask 60 becomes substantially equal at any part of the resist 58. In other words, the distance between the resist 58 and the photomask 60 can be made substantially constant.

  As described above, according to the present embodiment, the distance between the resist 58 and the photomask 60 is substantially constant, so that the altitudes of the preliminary corrugated portions 66 can be substantially uniform.

  Next, nickel electroforming is performed using the original stamper 56 provided with the preliminary corrugated portion 66. As a result, as shown in FIG. 8, a second plate stamper 72 made of Ni including the sub-pit portions 68 and the wavy portions 70 to which the shapes of the pre-pits 46 and the preliminary wavy portions 66 are respectively transferred is produced. The sub pit portion 68 is a convex portion protruding from the roughened surface forming surface of the second plate stamper 72, while the wavy portion 70 is recessed from the roughened surface forming surface.

  The second substrate 22 may be manufactured using the second plate stamper 72 as the master stamper 40, but the third plate stamper 74 made of Ni shown in FIG. 9 may be used as the master stamper 40. A fourth stamper 76 made of Ni shown in FIG. 10 may be used as the master stamper 40. A large number of the third plate stamper 74 and the fourth plate stamper 76 can be produced by nickel electroforming using the second plate stamper 72 as an original plate. Therefore, a significantly larger number than the second plate stamper 72 itself is used. A stamper can be prepared, which is advantageous in terms of cost.

  In the present embodiment, the third plate stamper 74 has a reverse pit portion 78 formed by a recess recessed from the roughened surface forming surface of the third plate stamper 74 by transferring the shape of the sub pit portion 68; The shape of the wavy portion 70 is transferred, and a reverse wavy portion 80 protruding from the roughened surface forming surface of the third plate stamper 74 is provided.

  Further, by the electroforming using the third plate stamper 74, the shape of the reverse pit portion 78 is transferred, and the forward pit portion 82 formed by the convex portion protruding from the roughened surface forming surface, and the reverse The fourth plate stamper 76 having the forward wave portion 84 protruding from the roughened surface forming surface is produced by transferring the shape of the wave portion 80.

  Whether to use the third plate stamper 74 or the fourth plate stamper 76 is selected depending on whether the portion protruding from the roughened surface of the second substrate 22 is a pit portion or a wavy portion. That's fine. That is, as shown in FIG. 11, when the second substrate 22 in which the pit portion 86 is depressed with respect to the roughened surface and the corrugated portion 88 is raised, the fourth plate stamper is used as the master stamper 40. 76 may be used. On the other hand, when producing the second substrate 22 with the pits raised with respect to the roughened surface and the corrugated part depressed, the third version stamper 74 may be used as the master stamper 40. .

  Each of the wave-like portion 70 of the second plate stamper 72, the reverse wave-like portion 80 of the third plate stamper 74, and the forward wave-like portion 84 of the fourth plate stamper 76 has the shape of the preliminary wave-like portion 66 in which the elevations in the original plate stamper 56 are substantially uniform. Are sequentially transferred, so that it is possible to obtain the second substrate 22 having the wave-like portions 88 whose altitudes are substantially uniform. In such a 2nd board | substrate 22, since incident light is scattered easily, the visibility of the visible image from an unspecified direction improves.

  As described above, by reducing the thickness of the original stamper 56 to 140 to 160 μm as compared with the prior art, it becomes easy to obtain an optical recording medium (optical disc 10) with improved visibility of a visible image.

  The wavy portion of the master stamper 40 has a maximum height (Rz) of the wavy portion of the roughened surface of the second substrate 22 of 0.1 to 5 μm, and the average length (RSm) of the roughness curve elements. ) Is preferably 1 to 500 μm. Here, “Rz” and “RSm” of the roughened surfaces of the master stamper 40 and the second substrate 22 are all measured by an atomic force microscope (AFM), an optical interference type roughness meter, a stylus type roughness meter, or the like. Can be measured. In particular, a stylus type roughness meter is suitable because the scanning length is long and the dynamic range in the depth direction is large.

  The original stamper 56 may be Cu, Al, Ni alloy, Cu alloy, or Al alloy.

[Recording method]
In the optical recording medium (optical disc) according to the present embodiment, one optical recording medium drive having a recording function for both layers is used for recording an image on the image recording layer and recording optical information on the information recording layer. Recording device). When one optical recording medium drive is used as described above, after recording on one of the image recording layer and the information recording layer, it can be reversed and recording can be performed on the other layer. Examples of the optical recording medium drive having a function of recording a visible image on the image recording layer are described in Japanese Patent Application Laid-Open Nos. 2003-203348 and 2003-242750.

  In recording a visible image on the image recording layer, the recording apparatus tracks the optical recording medium and the laser pickup with a tracking groove formed in the image recording layer, and follows the surface of the optical recording medium. Relative movement is performed, and in synchronization with the relative movement, laser light is modulated in accordance with image data such as characters and pictures to be imaged and irradiated toward the image recording layer to record a visible image. Such a configuration is described in, for example, Japanese Patent Application Laid-Open No. 2002-203321.

  Specifically, the image recording on the image recording layer of the optical recording medium according to the present embodiment is performed by recording the image information on the optical recording medium according to the present embodiment and at least the image recording layer of the optical recording medium. Using a recording device capable of recording.

  Hereinafter, a recording apparatus used for recording on the optical recording medium according to the present embodiment will be described.

(Optical recording medium recording device)
The recording of an image on the image recording layer of the optical recording medium according to the present embodiment and the recording of optical information on the information recording layer are performed by, for example, one optical recording medium drive (recording apparatus) having a recording function on both layers. ). When one optical recording medium drive is used as described above, after recording on one of the image recording layer and the information recording layer, it can be reversed and recording can be performed on the other layer.

  The optical recording medium according to this embodiment described above can be used particularly suitably for the following apparatuses and methods.

For example, an optical recording medium recording apparatus in which the above-described optical recording medium according to the present embodiment is preferably used is
(1) An optical recording medium recording apparatus for recording information by irradiating a recording surface (for example, an information recording layer (recording layer)) of an optical recording medium with a laser beam, the laser beam being applied to the optical recording medium An optical pickup that irradiates the optical recording medium, an irradiation position adjusting unit that adjusts an irradiation position of the laser beam on the optical recording medium by the optical pickup, and light in which the recording surface is formed on one surface and an image recording layer is formed on the other surface When the recording medium is set so that the image recording layer faces the optical pickup, the optical pickup and the optical pickup so that a visible image corresponding to image information is formed on the image recording layer of the optical recording medium. The image formation control means for controlling the irradiation position adjustment means, and the beam spot diameter of the laser beam irradiated by the optical pickup to the image recording layer when the visible image is formed are information Wherein the optical pickup comprises a beam spot control means for controlling the optical pickup to be larger than the beam spot diameter of the laser beam to be irradiated to the recording surface when performing the recording.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, the laser beam is irradiated to the image recording layer of the optical recording medium by increasing the beam spot diameter of the laser beam so that the laser is applied to a larger area while the optical recording medium is rotated once. Light can be irradiated, and the time required for forming a visible image can be shortened. Further, the optical recording medium according to the present embodiment described above can record a good visible image even by such a method.

Another aspect of the optical recording medium recording apparatus is:
(2) An optical recording medium recording apparatus that records information by irradiating a recording surface of an optical recording medium with laser light, and includes an optical pickup that irradiates the optical recording medium with laser light, and the optical pickup. An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical recording medium; and an optical recording medium in which the recording surface is formed on one surface and an image recording layer is formed on the other surface. Means for controlling the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the image recording layer of the optical recording medium when set so as to face the pickup; The intensity of the laser beam applied to the image recording layer by the optical pickup is a first intensity at which the image recording layer hardly changes based on the image information, or the first Image forming control means for controlling the image recording layer to have one of the second intensities greater than the intensity of the image recording layer, and detecting information relating to the laser beam irradiated to the optical recording medium by the optical pickup. And a servo unit that controls the optical pickup so that a desired laser beam is irradiated based on the detection result, and the image pickup control unit irradiates the optical pickup according to the control based on the image information. When the time during which the intensity of the laser beam is continuously the second intensity exceeds a certain time, the intensity of the laser beam irradiated from the optical pickup is a predetermined time regardless of the content of the image information. And the servo means controls the optical beam based on a detection result of information relating to the laser beam irradiated at the first intensity. To control the up.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, even if the intensity of the laser beam corresponding to the image data lasts for a long time, which is the second intensity for changing the image recording layer, the laser beam is used regardless of the image data. Since the first intensity laser beam that hardly changes the image recording layer is irradiated for the control, the laser beam control based on the irradiation result can be performed. Further, the optical recording medium according to the present embodiment described above can record a good visible image even by such a method.

Another aspect of the optical recording medium recording apparatus is:
(3) An optical recording medium recording apparatus for recording information by irradiating a recording surface of an optical recording medium with laser light, the optical pickup for irradiating the optical recording medium with laser light, and the optical pickup An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical recording medium; and the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the recording surface of the optical recording medium. Means for controlling, wherein the intensity of the laser light applied to the recording surface by the optical pickup is a first intensity at which the recording surface hardly changes based on the image information, or the first intensity. And an image formation control means for controlling the recording surface to be one of the second intensities changing, and irradiating the optical recording medium by the optical pickup. And servo means for controlling the optical pickup so that desired laser light is irradiated based on the detection result, and the image formation control means is based on the image information. Irradiated from the optical pickup regardless of the content of the image information when the time during which the intensity of the laser light irradiated by the optical pickup is continuously at the second intensity exceeds a certain time according to control. Control is performed so that the intensity of the laser beam becomes the first intensity for a predetermined time, and the servo means controls the optical pickup based on a detection result of information relating to the laser beam irradiated at the first intensity.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance of the recording layer is changed like an image to form a visible image corresponding to the image data. be able to. When such a visible image is formed, laser light control is performed regardless of the image data even when the laser light intensity corresponding to the image data is a second intensity that changes the recording surface for a long time. For this reason, the laser beam having the first intensity that hardly changes the recording surface is irradiated, so that the laser beam control based on the irradiation result can be performed. Further, the optical recording medium according to the present embodiment described above can record a good visible image even by such a method.

Another aspect of the optical recording medium recording apparatus is:
(4) An optical recording medium recording apparatus that records information by irradiating a recording surface of an optical recording medium with a laser beam, the optical pickup irradiating the optical recording medium with a laser beam, and the optical pickup An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical recording medium; and an optical recording medium in which the recording surface is formed on one surface and an image recording layer is formed on the other surface. Image forming control means for controlling the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the image recording layer of the optical recording medium when set so as to face the pickup. When the optical recording medium is set in the optical recording medium recording apparatus, the surface of the optical recording medium facing the optical pickup is the image recording layer. In either the based is comprises a relative position adjusting means for adjusting the relative positional relationship between the optical pickup and the optical pickup facing the surface of the optical recording medium.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When an optical recording medium is set, the positional relationship between the optical pickup and the surface facing the optical pickup is adjusted according to whether the image recording layer or the recording surface is set to face the optical pickup. can do. Therefore, when the recording surface is set to face the optical pickup, and when the image recording layer is set to face the optical pickup, the distance between the optical pickup and the surface facing the optical pickup is different. However, it is possible to suppress the problem that various controls such as focus control cannot be performed due to the difference in distance. Further, the optical recording medium according to the present embodiment described above can record a good visible image even by such a method.

Another aspect of the optical recording medium recording apparatus is:
(5) An optical recording medium recording apparatus that records information by irradiating a recording surface of an optical recording medium with a laser beam, the optical pickup irradiating the optical recording medium with a laser beam, and the optical pickup An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical recording medium; and an optical recording medium in which the recording surface is formed on one surface and an image recording layer is formed on the other surface, and is guided to the recording surface. When the optical recording medium in which the groove is formed in a spiral shape is set so that the image recording layer faces the optical pickup, the reflected light from the optical recording medium of the laser light irradiated by the optical pickup is changed. And a servo unit for controlling the irradiation position adjusting unit so that the laser beam is irradiated along the guide groove, and the servo unit moves the irradiation position of the laser beam along the guide groove. Is between which comprises an image formation control means which controls the laser beam visible image corresponding to image information is irradiated from the optical pickup to be formed on the image recording layer of the optical recording medium. Further, the optical recording medium according to the present embodiment described above can record a good visible image even by such a method.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. At this time, the irradiation of the laser beam is more complicated than when recording is performed on the recording surface by detecting the guide groove formed on the recording surface and moving the laser beam irradiation position along the detected guide groove. Visible image formation can be performed without performing position control.

Another aspect of the optical recording medium recording apparatus is:
(6) An optical recording medium recording apparatus for recording information by irradiating a recording surface of an optical recording medium with laser light, the optical pickup for irradiating the optical recording medium with laser light, and the optical recording medium A rotation driving means for rotating the recording medium, a clock signal output means for outputting a clock signal having a frequency corresponding to the rotation speed of the optical recording medium by the rotation driving means, and the recording surface on one side for image recording on the other side. When the optical recording medium on which the layer is formed is set so that the image recording layer faces the optical pickup, a visible image corresponding to image information is formed on the image recording layer of the optical recording medium. Means for controlling the optical pickup, wherein the signal output means controls the laser light emitted from the optical pickup based on the image information for each period of the clock signal. An image forming control unit; a rotation detecting unit for detecting that the optical recording medium is rotated once from a predetermined reference position by the rotation driving unit; and forming the visible image on the image recording layer of the optical recording medium. When the rotation detecting means detects that the optical recording medium has been rotated once from the predetermined reference position while being irradiated with the laser light from the optical pickup, the laser light from the optical pickup is used. Irradiation position adjusting means for moving the irradiation position by a predetermined amount in a predetermined radial direction of the optical recording medium set in the optical recording medium recording apparatus.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. During this visible image formation, laser light irradiation control for visible image formation is performed for each period of the clock signal having a frequency corresponding to the rotation speed of the optical recording medium, that is, every time the optical recording medium rotates by a certain angle. Therefore, a visible image having a content (for example, density) corresponding to the image data can be formed at a position at a certain angle of the optical recording medium. Further, the optical recording medium according to the present embodiment described above can record a good visible image even by such a method.

Another aspect of the optical recording medium recording apparatus is:
(7) An optical recording medium recording apparatus for recording information by irradiating a recording surface of an optical recording medium with laser light, the optical pickup for irradiating the optical recording medium with laser light, and the optical recording medium A rotation driving means for rotating the optical recording medium, a rotation detecting means for detecting that the optical recording medium is rotated once from a predetermined reference position by the rotation driving means, and an image on one side of the recording surface. When the optical recording medium on which the recording layer is formed is set so that the image recording layer faces the optical pickup, a visible image corresponding to image information is formed on the image recording layer of the optical recording medium. Image forming control means for controlling the optical pickup, and a laser beam irradiated by the optical pickup to form the visible image on the image recording layer of the optical recording medium. When the rotation detecting means detects that the optical recording medium has been rotated once from the predetermined reference position, the position of the laser beam emitted from the optical pickup is set in the optical recording medium recording apparatus. Irradiation position adjusting means for moving the recording medium by a predetermined amount in a predetermined radial direction, and the image formation control means is configured to cause the predetermined image recording layer of the optical recording medium to be rotated by the rotation driving means. In order to form the visible image from the reference position, the optical pickup is irradiated with laser light, while the irradiation position of the laser light is a predetermined amount ahead of the predetermined reference position of the optical recording medium. The optical pickup is controlled so that the laser beam for forming the visible image is not irradiated onto a region from a position to the predetermined reference position.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, a visible image is formed by irradiating a laser beam from the reference position of the optical recording medium while rotating the optical recording medium, and immediately before the laser light irradiation position returns to the reference position. The region is not irradiated with laser light for visible image formation. Therefore, the laser beam irradiation position control is disturbed for some reason, such as the rotation of the optical recording medium becoming unstable, and the optical recording medium is rotated once by continuing to irradiate the laser beam from the reference position. Even if the laser beam irradiation position moves to a position that passes through the position, that is, the position that overlaps with the position where the laser beam has already been irradiated later, the laser beam for visible image formation is irradiated to that position. This can prevent the deterioration of the quality of the visible image formed as a result.

Another aspect of the optical recording medium recording apparatus is:
(8) An optical recording medium recording apparatus that records information by irradiating a recording surface of an optical recording medium with a laser beam, the optical pickup irradiating the optical recording medium with a laser beam, and the optical pickup An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical recording medium; a disk identification means for acquiring disk identification information for identifying the type of the optical recording medium set in the optical recording medium recording apparatus; When an optical recording medium having the recording surface on one side and the image recording layer on the other side is set so that the image recording layer faces the optical pickup, the visible image corresponding to the image information Is means for controlling the optical pickup and the irradiation position adjusting means so as to be formed on the image recording layer of the optical recording medium, and is identified by the disc identifying means. Comprising an image forming control means for controlling the optical pickup and the irradiation position adjusting means according to the type of the optical recording medium.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, control for forming a visible image can be performed according to the type of the set disc.

Another aspect of the optical recording medium recording apparatus is:
(9) An optical pickup that irradiates a laser beam onto the optical recording medium, a modulation unit that modulates information supplied from the outside, and a laser that is irradiated from the optical pickup according to the information supplied from the modulation unit In an optical recording medium recording apparatus comprising a laser light control means for controlling light, the recording surface is visible with respect to the image recording layer of an optical recording medium in which the recording surface is formed on one surface and the image recording layer is formed on the other surface. When forming an image, when prohibiting means for prohibiting modulation by the modulating means for image information supplied from the outside, and when the image recording layer of the optical recording medium is set to face the optical pickup The laser light control means so that a visible image corresponding to unmodulated image information supplied from the modulation means is formed on the image recording layer of the optical recording medium. Gosuru comprising an image forming control unit.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, the image data is not modulated because the modulation by the modulation means for modulating the record data is prohibited when information is recorded on the recording surface. Accordingly, a data transfer configuration for recording information on the recording surface can be used in combination without providing a special data transfer configuration for forming a visible image corresponding to the image data.

Another aspect of the optical recording medium recording apparatus is:
(10) An optical recording medium recording apparatus for recording information by irradiating a recording surface of an optical recording medium with laser light, the optical pickup for irradiating the optical recording medium with laser light, and the optical pickup An irradiation position adjusting means for adjusting an irradiation position of the laser beam on the optical recording medium; and an optical recording medium in which the recording surface is formed on one surface and an image recording layer is formed on the other surface. Image forming control means for controlling the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the image recording layer of the optical recording medium when set so as to face the pickup. The image formation control means controls the laser light emitted from the optical pickup in accordance with the gradation level indicated in the image information.

  According to this configuration, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, laser light control can be performed according to the gradation of each position (coordinate) on the image recording layer indicated in the image data, and a visible image with gradation expression is formed. can do.

Another aspect of the optical recording medium recording apparatus is:
(11) An optical recording medium recording apparatus for recording information by irradiating a recording surface of an optical recording medium with laser light, a rotating means for rotating the optical recording medium, and an optical recording medium rotated by the rotating means In contrast, an optical pickup that emits laser light from the one surface and is movable in a substantially radial direction of the optical recording medium, and a laser emitted from the optical pickup when a visible image is formed on the image recording layer A means for adjusting a light level, wherein the recording layer and the image recording layer of the optical recording medium have a first intensity that hardly changes based on image data representing a visible image to be formed; The level of the laser beam emitted from the optical pickup is adjusted so as to be one of the second intensities that hardly change the layer and change the color development of the image recording layer. And a laser light level control means for settling.

  According to this apparatus, the optical recording medium according to the present embodiment can record information by irradiating the recording layer with laser light in the same manner as before, and can record information on the image recording layer. Thus, a visible image can be formed. Furthermore, since information recording and visible image formation can be performed by irradiating laser light from the same surface of the optical recording medium, the user is troublesome to turn the optical recording medium over and reset it. There is no need to work.

  In addition, the image forming method on the image recording layer of the optical recording medium according to the present embodiment includes an optical recording medium recording apparatus having an optical pickup that records information by irradiating the recording surface of the optical recording medium with laser light. And forming a visible image on the image recording layer formed on the surface opposite to the recording surface of the optical recording medium, wherein the irradiation position of the laser beam by the optical pickup is applied to the image recording layer. While moving along a predetermined spiral or concentric circumferential path, the laser beam emitted from the optical pickup is controlled so that a visible image corresponding to image information is formed on the image recording layer of the optical recording medium. In the control of the laser beam, a unit area is defined as an area including a predetermined number (several) of the paths belonging to each of the fan-shaped portions obtained by dividing the optical recording medium into a plurality of segments. Shading of the unit area to control the irradiation timing of the laser beam irradiated to each of the paths belonging to the unit region as represented.

  According to this method, by irradiating the image recording layer of the optical recording medium with laser light according to the image data, the reflectance changes like an image with the change in the absorbance of the image recording layer, so that the image data can be handled. A visible image can be formed. When such a visible image is formed, the laser beam irradiation timing control can be performed according to the gradation level of each position (coordinate) on the image recording layer indicated in the image data, and the visible image in which gradation expression is made Can be formed.

A. Specific Configuration of Optical Disc Recording Device 100 FIG. 12 is a block diagram showing the configuration of the optical disc recording device 100 according to the present embodiment.

  As described above, the optical disc recording apparatus 100 is an optical disc recording apparatus that records information by irradiating the information recording layer 18 of the optical disc 10 with the laser beam L. Only information recording on the information recording layer 18 is performed. Instead, a visible image corresponding to the image data Dg is formed by irradiating the image recording layer 24 of the optical disc 10 on which the image recording layer 24 is formed on the surface opposite to the information recording layer 18 with the laser light L. It has a function. In the optical disc recording apparatus 100, a visible image can be recorded not only on the image recording layer 24 but also on the information recording layer 18 for recording normal digital data on the optical disc 10 using a predetermined dye. .

-Specific Configuration of Optical Disc Recording Device 100-
As shown in FIG. 12, the optical disc recording apparatus 100 is connected to a host personal computer (PC) 148, and includes an optical pickup 106, a spindle motor 104, an RF (Radio Frequency) amplifier 150, a servo circuit 152, and the like. , Decoder 154, control unit 102, encoder 156, strategy circuit 158, laser driver 160, laser power control circuit 162, frequency generator 164, stepping motor 165, motor driver 166, and motor controller 168. A PLL (Phase Locked Loop) circuit 170, a FIFO (First In First Out) memory 172, a drive pulse generator 174, and a buffer memory 176.

  The spindle motor 104 is a motor that rotationally drives the optical disk 10 that is a data recording target, and the number of rotations is controlled by the servo circuit 152. In the optical disc recording apparatus 100 according to the present embodiment, for example, recording is performed by the CAV (Constant Angular Velocity) method, and therefore the spindle motor 104 is set to a constant set by an instruction from the control unit 102 or the like. It is designed to rotate at angular speed.

  The optical pickup 106 is a unit that irradiates the optical disk 10 rotated by the spindle motor 104 with the laser light L, and its configuration is shown in FIG.

  As shown in FIG. 13, the optical pickup 106 receives reflected light from a laser diode 178 that emits laser light L, a diffraction grating 180, an optical system 182 that focuses the laser light L on the surface of the optical disk 10, and the like. A light receiving element 184.

  In the optical pickup 106, the laser diode 178 emits a laser beam L having an intensity corresponding to the drive current when supplied with a drive current from a laser driver 160 (see FIG. 12). The optical pickup 106 separates the laser beam L emitted from the laser diode 178 into a main beam, a preceding beam, and a following beam by the diffraction grating 180, and these three laser beams are polarized beam splitter 186, collimator lenses 188, 1 / The light is condensed on the surface of the optical disc 10 through the four-wave plate 190 and the objective lens 192.

  Then, the three laser beams reflected on the surface of the optical disc 10 are transmitted again through the objective lens 192, the quarter wavelength plate 190, and the collimator lens 188, reflected by the polarization beam splitter 186, and passed through the cylindrical lens 194. The light is incident on the light receiving element 184. The light receiving element 184 outputs a received signal to the RF amplifier 150 (see FIG. 12), and the received light signal is supplied to the control unit 102 and the servo circuit 152 via the RF amplifier 150.

  The objective lens 192 is held by the focus actuator 196 and the tracking actuator 198 and can move in the optical axis direction of the laser light L and the radial direction of the optical disc 10. Each of the focus actuator 196 and the tracking actuator 198 moves the objective lens 192 in the optical axis direction and the radial direction according to the focus error signal and the tracking error signal supplied from the servo circuit 152 (see FIG. 12). The servo circuit 152 generates a focus error signal and a tracking error signal based on the light reception signal supplied via the light receiving element 184 and the RF amplifier 150, and moves the objective lens 192 as described above, thereby focusing. Perform control and tracking control.

  The optical pickup 106 has a front monitor diode (not shown). When the laser diode 178 emits the laser light L, a current is generated in the front monitor diode that has received the laser light L, A current is supplied from the optical pickup 106 to the laser power control circuit 162 shown in FIG.

  The RF amplifier 150 amplifies, for example, EFM (Eight to Fourier Modulation) modulated RF signal supplied from the optical pickup 106, and outputs the amplified RF signal to the servo circuit 152 and the decoder 154. The decoder 154 generates reproduction data by performing EFM demodulation on the EFM-modulated RF signal supplied from the RF amplifier 150 during reproduction.

  The servo circuit 152 is supplied with an instruction signal from the control unit 102, an FG pulse signal having a frequency corresponding to the rotation speed of the spindle motor 104 supplied from the frequency generator 164, and an RF signal from the RF amplifier 150. The servo circuit 152 performs rotation control of the spindle motor 104 and focus control and tracking control of the optical pickup 106 based on these supplied signals. As a driving method of the spindle motor 104 when information is recorded on the recording surface (information recording layer 18) of the optical disk 10 or when a visible image is formed on the image recording layer 24 (see FIG. 1) of the optical disk 10, the optical disk 10 Either a method of driving the optical disk D at a constant angular velocity (CAV: Constant Angular Velocity) or a method of rotating the optical disk D so as to have a constant recording linear velocity (CLV: Constant Linear Velocity) may be used. In the optical disc recording apparatus 100 according to the present embodiment, for example, the CAV method is adopted, and the servo circuit 152 rotates the spindle motor 104 at a constant angular velocity instructed by the control unit 102.

  The buffer memory 176 supplies information (record data Dw) to be recorded on the information recording layer 18 of the optical disc 10 and information (image data) corresponding to a visible image to be formed on the image recording layer 24 of the optical disc 10 supplied from the host PC 148. Dg) is accumulated. The recording data Dw accumulated in the buffer memory 176 is output to the encoder 156, and the image data Dg is output to the control unit 102.

  The encoder 156 performs EFM modulation on the recording data Dw supplied from the buffer memory 176, and outputs it to the strategy circuit 158. The strategy circuit 158 performs time axis correction processing on the EFM signal supplied from the encoder 156 and outputs the result to the laser driver 160.

  The laser driver 160 drives the laser diode 178 (see FIG. 13) of the optical pickup 106 in accordance with a signal modulated according to the recording data Dw supplied from the strategy circuit 158 and the control of the laser power control circuit 162.

  The laser power control circuit 162 controls the laser power emitted from the laser diode 178 (see FIG. 13) of the optical pickup 106. Specifically, the laser power control circuit 162 controls the laser driver 160 so that the laser beam L having a value that matches the target value of the optimum laser power instructed by the control unit 102 is emitted from the optical pickup 106. . The laser power control by the laser power control circuit 162 performed here uses a current value supplied from the front monitor diode of the optical pickup 106 to control the laser light L having a target intensity to be emitted from the optical pickup 106. Feedback control.

  In the FIFO memory 172, the image data Dg supplied from the host PC 148 and stored in the buffer memory 176 is supplied via the control unit 102 and sequentially stored. Here, the image data Dg stored in the FIFO memory 172, that is, the image data Dg supplied from the host PC 148 to the optical disc recording apparatus 100 includes the following information. This image data Dg is data for forming a visible image on the image recording layer 24 of the disc-shaped optical disc 10 and, as shown in FIG. 14, n on a number of concentric circles centering on the center Do of the optical disc 10. Information indicating the degree of gradation (shading) is described for each coordinate (indicated by black dots in the figure). The image data Dg includes coordinate points P11, P12... P1n belonging to a circle on the innermost circumferential side, and coordinates P21, P22,. P2n is data in which information indicating the degree of gradation of each coordinate point up to the coordinate Pmn of the outermost circle is described in the order of the coordinates belonging to the circle on the outer circumference side, and the FIFO memory 172 stores this data. Information indicating the gradation of each coordinate on the polar coordinates is supplied in the above order.

  FIG. 14 is a diagram schematically showing the positional relationship between the coordinates, and the actual coordinates are arranged more densely than those shown. When the host PC 148 creates image data to be formed on the photosensitive surface of the optical disc 10 in a commonly used bitmap format, the bitmap data is converted into the polar coordinate format data as described above. Then, the converted image data may be transmitted from the host PC 148 to the optical disc recording apparatus 100.

  When a visible image is formed on the image recording layer 24 of the optical disc 10 based on the image data Dg supplied as described above, a clock signal for image recording is supplied from the PLL circuit 170 to the FIFO memory 172. It has become so. Each time the clock pulse of the image recording clock signal is supplied, the FIFO memory 172 outputs to the drive pulse generation unit 174 information indicating the gray scale of one coordinate stored first. Yes.

  The drive pulse generator 174 generates a drive pulse for controlling the irradiation timing of the laser light L emitted from the optical pickup 106. Here, the drive pulse generation unit 174 generates a drive pulse having a pulse width corresponding to information indicating the gradation level for each coordinate supplied from the FIFO memory 172. For example, when the gradation of a certain coordinate is relatively large (when the density is large), as shown in FIG. 15A, the pulse width at the recording level (second intensity: intensity at which the optical characteristics of the image recording layer 24 change) is obtained. On the other hand, as shown in FIG. 15B, a drive pulse with a reduced recording level pulse width is generated for coordinates having a relatively small gradation.

  Here, the recording level is a power level at which the optical characteristics of the image recording layer 24 change when the image recording layer 24 of the optical disc 10 is irradiated with the laser power at that level, and the reflectance clearly changes. When the drive pulse as described above is supplied to the laser driver 160, the laser light L at the recording level is irradiated from the optical pickup 106 for a time corresponding to the pulse width.

  Therefore, when the gradation is large, the laser beam L having a long recording level is irradiated, and the reflectance changes in a larger region in the unit region of the image recording layer 24 of the optical disc 10, and as a result. The user visually recognizes that this area is a dark area. In the present embodiment, the gradation shown in the image data Dg is expressed by varying the length of the region whose reflectance is changed per unit region (unit length) as described above. The servo level (first intensity) is a power level at which the optical characteristics of the image recording layer 24 hardly change when the image recording layer of the optical disc 10 is irradiated with the laser power of that level, and the reflectance is changed. It is only necessary to irradiate the laser beam L of the servo level without irradiating the laser beam L of the recording level to the region that does not need to be performed.

  The drive pulse generation unit 174 generates a drive pulse according to the information indicating the gradation for each coordinate as described above, and performs laser power control by the laser power control circuit 162, focus control by the servo circuit 152, and When it is necessary to perform the tracking control, a recording level pulse for a very short period or a servo level pulse is inserted regardless of the information indicating the gradation level.

  For example, as shown in FIG. 16A, in order to express a visible image according to the gradation of a certain coordinate in the image data Dg, it is necessary to irradiate the recording level laser beam L over the period T1, and the period When T1 is longer than a predetermined servo cycle ST for controlling the laser power, a servo off-pulse having a servo level of a short time t when the servo cycle ST has elapsed from the time when the recording level pulse is generated. Insert (SSP1).

  On the other hand, as shown in FIG. 16B, in order to express a visible image according to the gradation of a certain coordinate in the image data Dg, it is necessary to irradiate the servo level laser beam L over a period longer than the servo cycle ST. After the servo cycle ST has elapsed since the servo level pulse was generated, a servo on pulse (SSP2) having a recording level of a short time t is inserted.

  As described above, the laser power control by the laser power control circuit 162 is performed by the current supplied from the front monitor diode that receives the laser light L emitted from the laser diode 178 (see FIG. 13) of the optical pickup 106 (of the irradiated laser light). (The current having a value corresponding to the intensity). More specifically, as shown in FIG. 17, the laser power control circuit 162 samples and holds a value corresponding to the intensity of the laser light L received by the front monitor diode 200 as described above (S201, S202). .

  Then, when the recording level laser beam L is irradiated, that is, when the recording level drive pulse (see FIGS. 15A to 16B) is generated, the result of sampling and holding (sample value) and the control unit 102 The laser power control is performed so that the sample value becomes the target value (S203).

  Further, when the servo level laser beam L is irradiated, that is, when a servo level drive pulse (see FIGS. 15A to 16B) is generated, the result of sampling and holding (sample value) and the control unit 102 Is compared with the target value of the servo level supplied from, and laser power control is performed so that the sample value becomes the target value (S204).

  Accordingly, when the recording level or servo level pulse is not continuously output for a time longer than the predetermined servo cycle ST (sample cycle), the servo off pulse SSP1 and the servo pulse are output as described above regardless of the content of the image data Dg. The on-pulse SSP2 is forcibly inserted so that the laser power can be controlled for each level as described above.

  Further, as described above, the servo off-pulse SSP1 is inserted not only for controlling the laser power but also for performing focus control and tracking control by the servo circuit 152. That is, in the tracking control and the focus control, the RF signal received by the light receiving element 184 (see FIG. 13) of the optical pickup 106, that is, the return light (reflected light) of the laser light L emitted from the laser diode 178 from the optical disk 10. Based on.

  Here, FIG. 18 shows an example of a signal received by the light receiving element 184 when the laser beam L is irradiated. As shown in FIG. 18, the reflected light when the laser beam L at the recording level is irradiated includes an element of a peak portion K1 when the laser beam L rises and then a shoulder portion K2 where the level becomes constant, In FIG. 18, the hatched portion is considered to be energy used for image formation of the image recording layer 24.

  The energy used for image formation of the image recording layer 24 is not always a stable value, and may vary depending on various situations. Therefore, in FIG. 18, it is considered that the shape of the shaded portion changes each time. That is, the reflected light of the laser light L at the recording level is not always obtained with a stable reflected light with a lot of noise. If reflected light is used, there is a risk that accurate focus control and tracking control may be hindered. Therefore, when the recording level laser beam L is continuously irradiated for a long time as described above, the reflected light of the servo level laser beam L cannot be obtained, and accurate focus control and tracking control can be performed. There is a risk of disappearing.

  Therefore, by inserting the servo off-pulse SSP1 as described above, the reflected light of the servo level laser light L can be periodically acquired, and focus control and tracking control are executed based on the acquired reflected light. . When forming a visible image on the image recording layer 24 of the optical disc 10, unlike the case of recording information on the information recording layer 18, it is necessary to trace along a pre-groove (guide groove) formed in advance. Absent. Therefore, in the present embodiment, the target value for tracking control is a fixed value (a constant offset voltage is set). Such a control method can be applied not only when a visible image is formed on the image recording layer 24 but also when a visible image is formed on the information recording layer 18. That is, when a material that changes not only the reflectance but also the color development when irradiated with the laser beam L is used for the information recording layer 18, a visible image can be formed on the information recording layer 18 as well as the image recording layer 24. Is possible. As described above, when a visible image is formed on the information recording layer 18, it is natural that original data recording cannot be performed on the portion where the visible image is formed. Therefore, a region for recording data and a region for forming a visible image are set in advance. It is preferable to separate them.

  As described above, the time for inserting the servo off-pulse SSP1 and the servo off-pulse SSP2 may be the minimum time within a range that does not hinder the execution of various servos such as laser power control, tracking control, and focus control. Preferably, by shortening the insertion time, various servos as described above can be performed with almost no influence on the formed visible image.

  Returning to FIG. 12, the PLL circuit 170 multiplies the FG pulse signal having a frequency corresponding to the rotational speed of the spindle motor 104 supplied from the frequency generator 164, and generates a clock signal used for forming a visible image, which will be described later. Output. The frequency generator 164 outputs an FG pulse signal having a frequency corresponding to the spindle rotational speed using a counter electromotive current obtained by the motor driver of the spindle motor 104.

  For example, as shown in FIG. 19A, when the frequency generator 164 generates eight FG pulses while the spindle motor 104 makes one revolution, that is, while the optical disc 10 makes one revolution. As shown in 19B, the PLL circuit 170 outputs a clock signal obtained by multiplying the FG pulse (for example, five times the frequency of the FG pulse signal, 40 high-level pulses during one rotation of the optical disk 10), that is, A clock signal having a frequency corresponding to the rotation speed of the optical disk 10 rotated by the spindle motor 104 is output. In this way, the clock signal obtained by multiplying the FG pulse signal is output from the PLL circuit 170 to the FIFO memory 172, and one clock is output to the clock signal every cycle, that is, every time the optical disk 10 rotates by a certain angle. Data indicating the degree of gradation is output from the FIFO memory 172 to the drive pulse generator 174. As described above, the PLL circuit 33 may be used to generate a clock signal obtained by multiplying the FG pulse. However, when the spindle motor 104 is a motor with sufficiently stable rotational drive capability. In this case, a crystal oscillator may be provided in place of the PLL circuit 170 to generate a clock signal obtained by multiplying the FG pulse as described above, that is, a clock signal having a frequency corresponding to the rotational speed of the optical disc 10.

  The stepping motor 165 is a motor for moving the optical pickup 106 in the radial direction of the optical disc 10 set on the optical disc 10. The motor driver 166 rotationally drives the stepping motor 165 by an amount corresponding to the pulse signal supplied from the motor controller 168. The motor controller 168 generates a pulse signal corresponding to the movement amount and movement direction in accordance with the movement start instruction including the movement direction and movement amount of the optical pickup 106 in the radial direction, which is instructed from the control unit 102, and sends the pulse signal to the motor driver 166. Output. The stepping motor 165 moves the optical pickup 106 in the radial direction of the optical disk 10, and the spindle motor 104 rotates the optical disk 10 with respect to the optical disk 10, so that the irradiation position of the laser light of the optical pickup 106 is changed to various positions on the optical disk 10. These components constitute the irradiation position adjusting means 108.

  The control unit 102 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls each unit of the optical disc recording apparatus 100 according to a program stored in the ROM. The recording process for the information recording layer 18 of the optical disc 10 and the image forming process for the image recording layer 24 of the optical disc 10 are centrally controlled.

B. Operation of Optical Disc Recording Device 100 Next, the operation of the optical disc recording device 100 will be described.

  As described above, the optical disc recording apparatus 100 can record the recording data Dw such as music data supplied from the host PC 148 on the information recording layer 18 of the optical disc 10 and record the image on the optical disc 10. A visible image corresponding to the image data Dp supplied from the host PC 148 can be formed on the layer 24.

  Hereinafter, operations of the optical disc recording apparatus 100 capable of performing processing such as information recording and visible image formation will be described with reference to FIGS.

  First, when the optical disc 10 is set in the optical disc recording apparatus 100, the control unit 102 controls the optical pickup 106 and the like, and what format is the optical disc facing the optical pickup 106 of the set optical disc 10. Is detected (step Sa1). For example, in the case of DVD-R, the presence or absence of a land pre-pit signal or pre-record signal, and in the case of DVD + R, the presence or absence of ADIP (Address in Pregroove) is detected. When these pieces of information are not recorded, the optical disk 10 is not recognized.

  Here, for example, when a land pre-pit signal or pre-record signal is detected in the case of DVD-R and ADIP is detected in the case of DVD + R from the set optical disk 10, the information recording layer 18 faces the optical pickup 106. Thus, it is determined that the optical disc 10 is set, and the control unit 102 controls the information recording layer 18 to record the recording data Dw supplied from the host PC 148 (step Sa2). Since the control for recording the recording data Dw performed here is the same as that of a conventional optical disk recording apparatus (DVD-R or DVD + R), description thereof is omitted.

  On the other hand, when the pre-pit signal Sp indicating that the optical disk is capable of drawing a visible image is detected based on the return light obtained by irradiating the innermost peripheral portion of the set optical disk 10 with laser light, It is determined that the optical disc 10 is set so that the image recording layer 24 faces the optical pickup 106, and the control unit 102 determines whether or not the disc ID of the set optical disc 10 can be obtained (step). Sa3). The disc ID of the optical disc D can be included in the pre-pit signal Sp.

  For example, as shown in FIG. 22, a visible image corresponding to information obtained by encoding a disc ID may be described along the circumference of the outermost peripheral portion of the optical disc 10 on the image recording layer 24 side. In the example of FIG. 22, the disk ID is formed by forming a reflective area 202 a and a non-reflective area 202 b having a length corresponding to the code (information obtained by coding the disk ID) along the circumference of the outermost periphery. It is described in the image recording layer 24 of the optical disc 10. The control unit 102 can acquire the disk ID from the reflected light by tracing the irradiation position of the laser light L of the optical pickup 106 along the outermost circumference of the optical disk 10.

  Therefore, as shown in FIG. 20, when the disc ID cannot be acquired, it can be determined that the optical disc 10 is a general optical disc (CD-R, DVD-R, etc.) that does not have the image recording layer 24. . In this case, the control unit 102 determines that the optical disk is incapable of forming a visible image (step Sa4), and performs processing for notifying the user of that fact.

  On the other hand, if the disk ID can be obtained from the optical disk 10, the host PC 148 waits until an image formation instruction including the image data Dg is received (step Sa5). In step Sa5, when there is an image formation instruction, the control unit 102 performs initialization control for forming a visible image on the image recording layer 24 of the optical disc 10 (step Sa6). More specifically, the control unit 102 controls the servo circuit 152 to rotate the spindle motor 104 at a predetermined angular velocity, and moves the optical pickup 106 to the initial position on the innermost peripheral side in the radial direction of the optical disc 10. Instruction is sent to the motor controller 168 to drive the stepping motor 165.

  Further, in the initialization control for image formation, the control unit 102 determines that the laser beam L having a beam spot diameter larger than the beam spot diameter when information recording is performed on the information recording layer 18 is performed on the image recording layer of the optical disc 10. The target value of the focus control can also be instructed to the servo circuit 152 so as to irradiate 24.

  The focus control for changing the beam spot diameter of the laser light L will be described more specifically.

  As described above, the focus control by the servo circuit 152 is performed based on the signal output from the light receiving element 184 of the optical pickup 106. When recording information on the information recording layer 18 of the optical disc 10, the servo circuit 152 is operated by the focus actuator so that circular return light is received at the centers of the four areas 184a, 184b, 184c and 184d of the light receiving element 184 shown in FIG. 196 (see FIG. 13) is driven. That is, the focus actuator 196 is driven so that (Fa + Fc) − (Fb + Fd) = 0 when the received light amounts of the areas 184a, 184b, 184c, and 184d are Fa, Fb, Fc, and Fd, respectively.

  On the other hand, when a visible image is formed on the image recording layer 24 of the optical disc 10, as described above, the image recording layer 24 is irradiated with the laser beam L having a diameter larger than that during information recording on the information recording layer 18. Thus, focus control is performed. When the shape of the return light received by the light receiving element 184 shown in FIG. 23 is an elliptical shape (see the ellipses 204b and 204c in FIG. 23), the spot size of the laser light L is larger than the case of the circular shape 204a described above. Since it is large, the servo circuit 152 drives the focus actuator 196 so that the return light having such an elliptical shape (see the ellipses 204b and 204c in FIG. 23) is received by the light receiving element 184. That is, the focus actuator 196 is driven so as to satisfy (Fa + Fc) − (Fb + Fd) = M (M is not 0). Therefore, the servo circuit 13 constitutes the beam spot control means 126.

  In the above-described initialization control for forming a visible image, the control unit 102 instructs the servo circuit 152 to set M (not 0) so that a laser beam having a larger spot diameter than that during information recording on the information recording layer 18 is obtained. L can be applied to the image recording layer 24 of the optical disc 10. As described above, when a visible image is formed on the image recording layer 24 of the optical disk 10, the following effects can be obtained by irradiating the laser beam L having a larger spot diameter than that during information recording on the information recording layer 18. Can do.

  That is, in the present embodiment, when forming a visible image, the laser beam L is irradiated while rotating the optical disc 10 as in the case of recording information on the information recording layer 18. Accordingly, by increasing the beam spot diameter of the laser beam L, a visible image can be formed on the entire area of the image recording layer 24 of the optical disc 10 in a shorter time.

  The reason for this will be described with reference to FIGS. 24A and 24B. As schematically shown in FIGS. 24A and 24B, when the beam spot diameter BS of the irradiated laser light L is small (see FIG. 24A) and large (see FIG. 24B), the optical disk 10 is rotated once. When the beam spot diameter BS is large, the area of the region for image formation becomes larger. For this reason, when the beam spot diameter BS is small, the entire optical disk 10 must be rotated in order to make the entire area an image formation target (in the example of FIGS. 17A and 17B, four rotations are required when the beam spot diameter BS is large). If it is small, 6 rotations), it takes a lot of time for image formation. For the reasons described above, the optical disc recording apparatus 100 is configured to irradiate the laser beam L having a larger spot diameter than that during information recording when forming a visible image.

  In the initialization control for image formation, the control unit 102 sets the target value of each level so that the recording level and servo level laser light L corresponding to the acquired disk ID is emitted from the optical pickup 106. Is instructed to the laser power control circuit 162.

  That is, the ROM of the control unit 102 stores a target value to be set as a recording level and a servo level for each of a plurality of types of disk IDs, and the control unit 102 records the recording level corresponding to the acquired disk ID. Then, the servo level target values are read out, and these target values are instructed to the laser power control circuit 162.

  In this way, the power target value is set according to the disk ID for the following reason.

  That is, it is conceivable that the characteristics of the dye of the image recording layer 24 differ depending on the type of the optical disc 10, and when the characteristics of the dye are different, the optical characteristics such that the reflectivity changes when the laser beam L is irradiated to what extent. Of course it will be different. For this reason, even when the image recording layer 24 of a certain optical disk 10 is irradiated with laser light L having a certain recording level, the reflectance of the irradiated area can be changed sufficiently, another optical disk When 10 image recording layers 24 are irradiated with the laser beam L having the same recording level, the reflectance of the irradiated area cannot always be changed. Therefore, in the present embodiment, the target values of the recording level and the servo level that can perform accurate image formation are obtained in advance by experiment for each optical disk corresponding to each of various disk IDs as described above.

  Then, the obtained target value is associated with each disk ID, that is, a table is stored in the ROM, so that the optimum power according to the characteristics of the image recording layers of the various optical disks 10 as described above can be obtained. It is possible to control.

  When the initialization control as described above is performed by the control unit 102, thereafter, a process for forming a visible image on the image recording layer 24 of the optical disc 10 is performed.

  That is, as shown in FIG. 21, first, the control unit 102 transfers the image data Dg supplied from the host PC 148 via the buffer memory 176 to the FIFO memory 172 (step Sa7). Then, from the FG pulse signal supplied from the frequency generator 164, the control unit 102 passes a predetermined reference position of the optical disk 10 rotated by the spindle motor 104 from the irradiation position of the laser light L of the optical pickup 106. Is determined (step Sa8).

  Here, a method for detecting whether or not the predetermined reference position and the irradiation position of the laser beam L have passed the position will be described with reference to FIGS.

  As shown in FIG. 25, the frequency generator 164 outputs a predetermined number of FG pulses (eight in the example of FIG. 25) while the spindle motor 104 makes one revolution, that is, while the optical disk 10 makes one revolution. Therefore, the control unit 102 uses any one of the FG pulses supplied from the frequency generator 164 as a reference pulse, and outputs a reference position detection pulse synchronized with the rising timing. Thereafter, the reference position detection pulse is output in synchronization with the rising timing of the FG pulse of the number of one rotation (eighth in the example of FIG. 25) from the reference position detection pulse. In this way, a reference position detection pulse signal is generated.

  By generating such a reference position detection pulse, the time when the reference position detection pulse is generated is the timing when the irradiation position of the laser light L of the optical pickup 106 passes through the reference position of the optical disc 10. Can be recognized.

  That is, as shown in FIG. 26, the irradiation position of the laser beam L of the optical pickup 106 at the timing when the first reference position detection pulse is generated is indicated by a thick line (line indicated by reference numeral 206: optical pickup 106 in FIG. Since the position that can be taken by the irradiation position is represented by a line because it is movable in the radial direction, the reference position detection pulse generated after one rotation is naturally generated. The irradiation position of the laser beam L of the optical pickup 106 is at a position indicated by a thick line in FIG.

  In this way, the radial line to which the irradiation position of the laser beam L belongs becomes the reference position at the timing at which the reference position detection pulse is first generated, and the control unit 102 performs the rotation of the optical disc 10 once as described above. It is possible to detect that the irradiation position of the laser beam L has passed the reference position of the optical disc 10 based on the reference position detection pulse generated at the same time.

  In FIG. 26, an alternate long and short dash line (a line denoted by reference numeral 208) indicates an irradiation position of the laser light L after a certain reference position detection pulse is generated until a next reference position detection pulse is generated. An example of a movement locus is shown.

  After receiving an image formation instruction from the host PC 148, when it is detected that the reference position of the optical disc 10 has passed the irradiation position of the laser beam L by the above-described method, the control unit 102 sets 1 to the variable R indicating the rotation speed. Is incremented (step Sa9), it is determined whether or not R is an odd number (step Sa10).

  Here, when it is first detected that the reference position has been passed after receiving the image formation instruction, R = 0 (initial value) + 1 = 1. In this case, in step Sa10, R is an odd number. It will be determined that there is. As described above, when it is determined that R is an odd number, the control unit 102 performs control for forming a visible image by irradiating the image recording layer 24 of the optical disc 10 with the laser light L from the optical pickup 106 (step). Sa11). More specifically, the control unit 102 sequentially outputs the image data Dg from the FIFO memory 172 in synchronization with the clock signal output from the PLL circuit 170 from the time when the reference position detection pulse is received. Control each part. With this control, as shown in FIG. 27, the FIFO memory 172 outputs information indicating the gradation of one coordinate to the drive pulse generation unit 174 every time a clock signal is supplied from the PLL circuit 170. The drive pulse generation unit 174 generates a drive pulse having a pulse width according to the gradation shown in the information and outputs the drive pulse to the laser driver 160. As a result, the optical pickup 106 irradiates the image recording layer 24 of the optical disc 10 with the laser light L at the recording level only for the time corresponding to the gradation of each coordinate, and the reflectance of the irradiated region changes. A visible image as schematically shown in FIG. 28 can be formed.

  As schematically shown in FIG. 28, since the optical disk 10 is rotated by the spindle motor 104, the irradiation position of the laser light L of the optical pickup 106 is one cycle of the clock signal (the next pulse from the rising timing of the pulse). During the period until the rising timing), the region moves along the circumference by the region indicated by C in FIG. While the irradiation position of the laser beam L passes through the region C, the time during which the recording level laser beam L is to be irradiated is changed according to the gradation, so that as shown in FIG. The reflectance of different areas can be changed according to different gradation levels. In this way, by controlling the irradiation time of the laser beam L at the recording level when passing through each region C according to the gradation of each coordinate, a visible image corresponding to the image data Dg is recorded on the optical disc 10. The layer 24 can be formed.

  As described above, when the control for executing the formation of the visible image is executed by the irradiation of the laser beam L controlled according to the image data Dg, the process of the control unit 102 returns to Step Sa7 and the buffer memory 176 is processed. The image data Dg supplied from is transferred to the FIFO memory 172. Then, it is detected whether or not the irradiation position of the laser beam L of the optical pickup 106 has passed through the reference position of the optical disc 10, and when it is detected that the reference position has passed, 1 is incremented to the variable R. As a result, when the variable R becomes an even number, the control unit 102 controls each unit of the apparatus so as to stop the visible image formation by the laser beam irradiation control as described above (step Sa12). More specifically, the FIFO memory 172 is controlled not to output information indicating the gradation of each coordinate to the drive pulse generator 174 in synchronization with the clock signal supplied from the PLL circuit 170. That is, the control unit 102 irradiates the image recording layer 24 of the optical disc 10 with the laser light L at the recording level to form a visible image, and then the image recording layer 24 for the next rotation of the optical disc 10. Control is performed so as not to irradiate the laser beam L for changing the reflectance.

  Thus, when the irradiation of the laser beam L for forming a visible image is stopped, the control unit 102 instructs the motor controller 168 to move the optical pickup 106 to the outer peripheral side in the radial direction by a predetermined amount ( In step Sa13), the motor controller 168 drives the stepping motor 165 via the motor driver 166 in response to the instruction, thereby moving the optical pickup 106 to the outer peripheral side by a predetermined amount.

  Here, as described above, the predetermined amount by which the optical pickup 106 is moved in the radial direction of the optical disk 10 may be appropriately determined according to the beam spot diameter BS (see FIGS. 24A and 24B) irradiated from the optical pickup 106. Good. That is, when a visible image is formed on the image recording layer 24 of the disc-shaped optical disc 10, it is possible to move the irradiation position of the laser beam L of the optical pickup 106 on the surface of the optical disc 10 with almost no gap. Necessary for realizing image formation.

  Accordingly, if the unit movement amount of the optical pickup 106 in the radial direction as described above is substantially the same as the beam spot diameter BS of the laser light L irradiated onto the optical disc 10, there is substantially a gap on the surface of the optical disc 10. Therefore, it is possible to irradiate the laser beam L without any problem, and it is possible to form a higher quality image.

  Depending on various factors such as the properties of the image recording layer 24, there may be a case where an area larger than the irradiated beam spot diameter BS develops color. In such a case, the adjacent color development is considered in consideration of the width of the color development area. The unit movement amount may be determined so that the areas do not overlap. In the present embodiment, since the beam spot diameter BS is made larger than that during recording on the information recording layer 18 (for example, about 20 μm), the control unit 102 emits light for approximately the same length as the beam spot diameter BS. The motor controller 168 is controlled to drive the stepping motor 165 so as to move the pickup 106 in the radial direction. The stepping motor 165 in recent years can control the amount of movement in units of 10 μm by using microstep technology, and the optical pickup 106 can be controlled in units of 20 μm using the stepping motor 165 as described above. Moving in the radial direction is sufficiently feasible.

  As described above, when control is performed to move the optical pickup 106 by a predetermined amount in the radial direction, the control unit 102 changes the target value of the recording level of the laser light L, and uses the changed target value for the laser power control circuit. 162 is instructed (step Sa14). In the present embodiment, the CAV method in which the optical disc 10 is irradiated with the laser light L while rotating the optical disk 10 while keeping the angular velocity constant is adopted as a method for forming a visible image. When moved to the outer peripheral side, the linear velocity increases. Therefore, when the optical pickup 106 is moved in the radial direction (outer peripheral side), the target value of the recording level is changed so as to be larger than the value before moving in the radial direction. Thereby, even if the linear velocity changes, it is possible to irradiate with a laser power having an intensity that can sufficiently change the reflectance of the image recording layer 24 of the optical disc 10.

  As described above, when the movement control in the radial direction of the optical pickup 106 and the control for changing the target value of the recording level are executed, the control unit 102 performs unprocessed image data Dg, that is, driving for forming a visible image. It is determined whether or not there is image data Dg that has not been supplied to the pulse generation unit 174. If there is no image data Dg, the process ends.

  On the other hand, if there is unprocessed image data Dg that has not been supplied to the drive pulse generator 174, the process returns to step Sa7 to continue the process for forming a visible image.

  That is, the image data Dg is transferred from the control unit 102 to the FIFO memory 172 (step Sa7), and it is determined whether or not the irradiation position of the laser light L has passed the reference position of the optical disc 10 (step Sa8). When the reference position is passed, 1 is incremented to the variable R indicating the rotational speed (step Sa9), and it is determined whether or not the incremented variable R is an odd number (step Sa10). Here, when the variable R is an odd number, the control unit 102 controls each part of the apparatus so that the laser light L for forming a visible image as described above is irradiated, and the variable R is an even number. In such a case, the irradiation of the laser beam L for forming a visible image is stopped (the laser beam L at the servo level is irradiated), and the optical pickup 106 is controlled to move in the radial direction as described above, Control such as changing the target value is performed.

  That is, when the control unit 102 irradiates the optical disk 10 with the laser light L for image formation (including the recording level) during a certain round, the laser for image formation is performed during the next round. Control is performed so as not to irradiate the light L, and movement of the optical pickup 106 in the radial direction is controlled during the circulation.

  In this way, by performing the control for moving the optical pickup 106 during the lap when image formation is not performed, the control for changing the recording level target value, and the like, the irradiation position and the power of the laser beam L irradiated with the control are performed. The visible image is not formed while the value or the like is fluctuating, and the irradiation of the laser beam L for image formation can be executed after the irradiation position and the intensity of the laser beam L are stabilized. Therefore, it is possible to suppress degradation of the quality of the visible image formed due to the radial movement control of the optical pickup 106 as described above.

  According to the optical disc recording apparatus 100 according to the present embodiment, each part of the apparatus such as the optical pickup 106 used for recording information on the information recording layer 18 is provided as much as possible without newly providing printing means or the like. The visible image corresponding to the image data Dg can be formed by irradiating the image recording layer 24 of the optical disc 10 on which the image recording layer 24 is formed with the laser beam L.

  In the present embodiment, the laser beam L is generated based on the clock signal generated using the FG pulse generated according to the rotation of the spindle motor 104, that is, the clock signal generated according to the rotation amount of the optical disc 10. Therefore, the irradiation position of the laser beam L can be grasped in the optical disc recording apparatus 100 without acquiring position information from the optical disc 10 side. Therefore, according to the optical disc recording apparatus 100, there is no restriction that the optical disc 10 subjected to special processing such as forming a pre-groove (guide groove) in the image recording layer 24 must be used, and the pre-groove and position information are not required. A visible image corresponding to the image data Dg can also be formed on the image recording layer 24 on which no or the like is previously formed.

  Next, recording of information (digital information) on the information recording layer 18 will be described. When the information recording layer 18 is a pigment type, first, the laser beam L is irradiated from the optical pickup 106 while rotating the unrecorded optical disk 10 at a predetermined recording linear velocity. By this irradiated laser light, the dye of the information recording layer 18 absorbs the light and the temperature rises locally, a desired pit is generated and its optical characteristics are changed, so that information is stored in the information recording layer 18. To be recorded.

  The recording waveform of the laser beam L may be a pulse train or a single pulse when one pit is formed. The ratio to the actual recording length (pit length) is important.

  The pulse width of the laser beam L is preferably in the range of 20 to 95%, more preferably in the range of 30 to 90%, and still more preferably in the range of 35 to 85% with respect to the length to be actually recorded. Here, when the recording waveform is a pulse train, the sum is in the above range.

  The power of the laser beam L varies depending on the recording linear velocity, but when the recording linear velocity is 3.5 m / s, the range of 1 to 100 mW is preferable, the range of 3 to 50 mW is more preferable, and the range of 5 to 20 mW is preferable. Further preferred. Further, when the recording linear velocity is doubled, the preferable range of the power of the laser beam L is 21/2 times, respectively.

  In order to increase the recording density, the NA (numerical aperture) of the objective lens 192 used in the optical pickup 106 is preferably 0.55 or more, and more preferably 0.60 or more.

  In the present embodiment, a semiconductor laser having an oscillation wavelength in the range of 350 to 850 nm can be used as the laser light L.

  On the other hand, the case where the information recording layer 18 is a phase change type will be described. In the case of the phase change type, it is made of the above-described material, and the phase change between the crystalline phase and the amorphous phase can be repeated by irradiation with the laser beam L.

  At the time of information recording, a concentrated pulse of laser light L is irradiated for a short time to partially melt the phase change recording layer. The melted portion is rapidly cooled by thermal diffusion and solidified to form an amorphous recording mark. At the time of erasing, the recording mark portion is irradiated with laser light L, heated to a temperature not higher than the melting point of the information recording layer 18 and not lower than the crystallization temperature, and then cooled, whereby the amorphous recording mark is crystallized. To the original unrecorded state.

It is sectional drawing which abbreviate | omits and shows an example of the optical disk applied to the optical disk recording device concerning this Embodiment. It is sectional drawing which expands and shows the part of the prepit area | region in an optical disk. It is a top view which shows the optical disk which concerns on a modification. FIG. 3 is an enlarged longitudinal sectional view of a main part of the optical recording medium stamper according to the present embodiment. FIG. 5 is an enlarged vertical cross-sectional view of a main part of an original stamper for producing the optical recording medium stamper of FIG. 4. FIG. 6 is an enlarged vertical cross-sectional view of a main part showing a state in which a photomask is disposed after a resist is applied to the original stamper of FIG. 5. FIG. 7 is an enlarged vertical sectional view of a main part showing a state where a part of the resist is peeled off, following FIG. 6. FIG. 8 is an enlarged vertical cross-sectional view of a main part of a second plate stamper manufactured by nickel electroforming using the original stamper of FIG. 7. FIG. 9 is an enlarged longitudinal sectional view of a main part of a third plate stamper manufactured by nickel electroforming using the second plate stamper of FIG. 8. FIG. 10 is an enlarged vertical cross-sectional view of a main part of a fourth plate stamper manufactured by nickel electroforming using the third plate stamper of FIG. 9. FIG. 11 is an enlarged vertical cross-sectional view of a main part of a second substrate formed by transferring the shape of the fourth plate stamper of FIG. 10. It is a block diagram which shows an example of the specific structure of the recording device for recording information and a visible image on the optical recording medium based on this Embodiment. It is a block diagram which shows an example of a specific structure of an optical pick-up. It is a figure for demonstrating the content of the image data used in order to form a visible image with respect to the image recording layer of an optical disk. FIG. 15A is a waveform diagram showing the output timing of the recording level and the servo level when the gradation is large, and FIG. 15B is a waveform diagram showing the output timing of the recording level and the servo level when the gradation is small. FIG. 16A is a waveform diagram showing timing when a servo off pulse is inserted, and FIG. 16B is a waveform diagram showing timing when a servo on pulse is inserted. It is a block diagram which shows the control system of the laser power by a laser power control circuit. It is a wave form diagram which shows the return light of the laser beam irradiated to the image recording layer of the optical disk from the optical pick-up. FIG. 19A is a waveform diagram showing an FG pulse generated according to the amount of rotation of the spindle motor by the frequency generator, and FIG. 19B is a waveform diagram showing a clock signal generated based on the FG pulse. 13 is a flowchart (No. 1) illustrating a processing operation of the recording apparatus in FIG. 13 is a flowchart (No. 2) showing a processing operation of the recording apparatus of FIG. It is explanatory drawing which shows an example of disk ID recorded on the outer peripheral side of the image recording layer of an optical disk. It is explanatory drawing which shows the shape of the return light of the laser beam received by the light receiving element of an optical pick-up. It is explanatory drawing which shows an example of the drawing state when the spot diameter of the laser beam radiate | emitted from an optical pick-up is large, and is explanatory drawing which shows an example of the drawing state when a spot diameter is small. It is explanatory drawing which shows an example of the method of producing | generating the pulse for a reference position detection based on the reference pulse selected from the FG pulse. It is explanatory drawing which shows an example of the method of detecting that the irradiation position of the laser beam passed the reference position of the optical disk based on the reference position detection pulse. 6 is a timing chart showing output timings of an FG pulse, a reference position detection pulse, a clock signal, and a drive pulse when a visible image is formed by irradiating an image recording layer of an optical disc with a laser beam. It is explanatory drawing which shows the example which changes the irradiation area of a laser beam according to a gradation degree with respect to the image recording layer of an optical disk, and records a visible image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a ... Optical disk 12 ... 1st laminated body 14 ... 2nd laminated body 16 ... 1st board | substrate 18 ... Information recording layer 20 ... 1st reflective layer 22 ... 2nd board | substrate 24 ... Image recording layer 26 ... 2nd reflective layer 28 ... Adhesive layer 30 ... Prepit area 32 ... Prepit 34 ... Image recording layer forming area 40 ... Master stamper 46 ... Prepit 48 ... Top 50 ... Bottom 52 ... Wavy 56 ... Original stamper 58 ... Register 60 ... Photomask 62 ... Top 64 ... Bottom 66 ... Preliminary corrugated part 68 ... Sub pit part 70 ... Corrugated part 72 ... Second edition stamper 74 ... Third edition stamper 76 ... Fourth edition stamper 78 ... Reverse pit part 80 ... Reverse corrugated part 82 ... Forward pit part 84 ... Forward wave part 86 ... Pit part 88 ... Wave part 100 ... Optical disk recording device 102 ... Control part 104 ... Spindle motor 106 ... Optical pickup 108 ... Irradiation position Sei means 126 ... beam spot control means

Claims (5)

A method for manufacturing a stamper for an optical recording medium, wherein a wave-shaped portion having a curved top portion and a bottom portion is provided on an end surface for roughening a substrate constituting the optical recording medium,
Applying a resist to a master stamper having a thickness of 140 to 160 μm provided by electroforming;
Irradiating the resist with light through the photomask after disposing a photomask away from the resist, and providing a preliminary wave-like portion connected to the resist with a curved top and bottom; and
A step of providing a second plate stamper provided with a corrugated portion to which the shape of the preliminary corrugated portion is transferred by electroforming using the original stamper provided with the preliminary corrugated portion;
A method of manufacturing a stamper for an optical recording medium, comprising:   2. The method for manufacturing a stamper for an optical recording medium according to claim 1, wherein a distance between the resist and the photomask is 5 to 200 [mu] m.   3. The manufacturing method according to claim 1 or 2, further comprising a step of providing a third plate stamper having an inverted wave portion to which the shape of the wave portion is transferred by electroforming using the second plate stamper. A method for manufacturing a stamper for an optical recording medium.   4. The manufacturing method according to claim 3, further comprising a step of providing a fourth plate stamper having a forward wave-like portion to which the shape of the reverse wave-like portion is transferred by electroforming using the third plate stamper. Manufacturing method of stamper for optical recording medium.   5. The manufacturing method according to claim 1, wherein the original stamper is provided with a pit portion having a concave portion or a convex portion formed on one end surface thereof, and the preliminary stamper is provided with respect to the one end surface. A method for manufacturing a stamper for an optical recording medium, comprising providing a wave-shaped portion.

Images