JP2008159194A - Optical disk and image recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk capable of additionally recording an image by using a laser beam and to provide an image recording method. <P>SOLUTION: In the optical disk having a substrate and a visible information recording layer formed on the substrate and capable of recording visible information by irradiation with the laser beam, pregrooves are formed on the surface on the visible information recording layer side of the substrate. In the image recording method, after the image is formed by irradiating the visible information recording layer with the laser beam in the optical disk, information for image recording is recorded in the pregrooves and the image is additionally recorded by irradiating the visible information recording layer with the laser beam based on the information recorded in the pregrooves. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc capable of drawing with a laser beam and an image recording method.

  As for optical discs such as DVD-R type, optical discs having an ink receiving layer (printing layer) on the label surface (the surface opposite to the side irradiated with laser light during recording or reproduction) have been put into practical use. ing. The user can print a photograph or a picture on the print layer using an ink jet printer or the like.

  Means for printing an image with an ink jet printer or the like are improving day by day, and the image quality is very excellent. However, on the other hand, it is costly to prepare a new ink jet printer or the like for forming an image. In addition, after recording information on the optical disk, moving the optical disk to an inkjet printer or the like to form an image is a time-consuming operation. When recording information on a plurality of optical disks and further forming an image, The trouble is felt very complicated.

Therefore, an image forming apparatus and an image forming method capable of recording an image with a high contrast ratio on an optical disc in addition to information recording on a recording surface have been proposed (for example, see Patent Document 1). Some optical recording media that can be drawn by laser light irradiation are also known (see, for example, Patent Documents 2 to 4). However, once these are inserted into the drive and drawn, they cannot be added thereafter. Therefore, it is not possible to cope with the case where the image is recorded in two times or when it is desired to record an image after the image is recorded. In such a case, it is considered that the convenience is further improved if there is an optical disc on which an image can be additionally recorded.
Japanese Patent Laid-Open No. 2004-005848 JP 2000-113516 A JP 2001-283464 A JP 2000-173096 A

  The object of the present invention is to solve the above-described conventional problems. That is, an object of the present invention is to provide an optical disc and an image recording method capable of additionally recording an image with a laser beam.

The above object is achieved by the present invention described below.
That is, the present invention is an optical disc having a substrate and a visible information recording layer formed on the substrate and capable of recording visible information by irradiation with laser light, and the surface of the substrate on the visible information recording layer side An optical disc in which pregrooves are formed.

  It is preferable to apply at least one of the following first to third embodiments to the optical disc of the present invention.

(1) The first aspect is an aspect in which prepits are further formed on the surface of the substrate on the visible information recording layer side.
(2) A 2nd aspect has a reflection layer, The inner periphery of the said visible information recording layer is larger than the inner periphery of the said board | substrate and the said reflection layer, The inner periphery of the said reflection layer, and the said visible information recording layer Information that is visible is drawn on the substrate between the inner periphery of the substrate and the information that is visible on the substrate is the unevenness formed by transferring the uneven shape of the stamper used in the step of forming the substrate. It is the aspect drawn by the shape.
(3) A 3rd aspect is an aspect in which the area | region where the said visually recognizable information was drawn is located in the radius 7.5-20 mm.
(4) A fourth aspect is an aspect in which the pregroove is formed on the inner peripheral side of the region where the visible information recording layer is formed.
(5) A fifth aspect is an aspect in which the visible information recording layer is formed on a region where the pregroove is formed.

  Further, the present invention provides the above-described optical disc of the present invention by irradiating the visible information recording layer with laser light to form an image, and then recording information related to image recording in the pregroove, On the basis of the recorded information, the visible information recording layer is irradiated with a laser beam to additionally record an image.

  According to the optical disk of the present invention, it is possible to provide an optical disk and an image recording method capable of additionally recording an image with a laser beam.

[Optical disk and manufacturing method thereof]
The optical disk of the present invention has a visible information recording layer on a substrate that can draw an image that can be visually recognized by laser light irradiation. A pregroove is formed on the surface of the substrate on the side where the visible information recording layer is formed. In the present specification, the “pre-groove” refers to a groove according to the present invention formed on the substrate surface on the side where the visible information recording layer is formed.

  Here, “the substrate on the side on which the visible information recording layer is formed” means that, when the optical disc of the present invention is a bonded optical disc, the substrate that is the closest of the two substrates, or is bonded. A substrate on which a visible information recording layer is formed in the previous laminate.

  The pregroove is provided for the user to record information (visual information) related to image recording. For example, when it is desired to record an image once and then record an image again, information about an unrecorded area is written into the pregroove after the image is recorded once. Thereafter, when the image is recorded again, the information can be read and the image can be additionally recorded.

  The pregroove is preferably formed on the inner peripheral side of the region where the visible information recording layer is formed in order to secure a necessary and sufficient reflected signal for reading. Here, the “inner peripheral side” means the inner side of the center in the radial direction of the region where the visible information recording layer is provided.

  In addition, in order to facilitate writing of information relating to an image non-recorded area, a visible information recording layer is preferably formed on the area where the pregroove is formed.

  In consideration of providing a tracking function for recording a high-definition image on the visible information recording layer, the track pitch of the pregroove is in the range of 0.3 to 200 μm from the viewpoint of the intensity distribution of the recording laser. It is preferable to make it into the range of 0.6-100 micrometers, and it is more preferable to set it as 0.7-50 micrometers.

  In addition, when tracking is performed during image recording and the substrate thickness is 0.6 mm, the depth of the pregroove is preferably 50 to 250 nm, more preferably 80 to 200 nm, and 100 More preferably, it is set to ˜180 nm. The half width of the pregroove is preferably 100 to 600 nm, more preferably 200 to 500 nm, and further preferably 250 to 450 nm. Note that the optimum range of the groove shape may differ depending on the wavelength of the laser beam, NA, substrate thickness, and the like.

  Further, it is preferable that prepits are formed together with pregrooves on the surface of the substrate on which the visible information recording layer is formed. The pre-pit includes information indicating that drawing on the visible information recording layer is possible, and information on drawing of the visible information recording layer such as a drawing laser power and a light emission pattern. Can be made easier. Further, high drawing characteristics can be exhibited using information related to drawing. Other information included in the prepit includes manufacturer information and the like.

  The area where the prepits are formed is not particularly limited. In other words, the prepits may be formed on the inner peripheral side of the region where the visible information recording layer is formed.

  When the pregroove and the prepit are provided, it is preferable that the prepit 600 and the pregroove 610 are sequentially provided from the inner peripheral side as shown in FIG. In addition, the area where the prepit 600 is formed (prepit formation area) and the pregroove 610 (pregroove formation area) are more peripheral than the area where the visible information recording layer is formed (visible information recording layer formation area 602). May be on the side. By being on the inner peripheral side, the prepits are not filled with the dye compound, so that there is an advantage that signal detection is easy.

  In order not to form the visible information recording layer in the pre-pit formation area, a margin area is required between the outermost periphery of the pit formation area and the innermost periphery of the area where the visible information recording layer is formed. . From the viewpoint of securing the visible information recording layer forming region as wide as possible, as shown in FIG. 1, the region where the prepit 600 is formed and the visible information recording layer 524 formed thereon may partially overlap. . That is, at least a part of the visible information recording layer 524 may be formed on the prepit 600.

  When the pregroove and the prepit are provided on the inner periphery of the substrate, it is preferable to provide the pregroove and the prepit within a radius of 21 to 24 mm from the center of the substrate.

As shown in FIG. 2, it is preferred that the average depth _{h p} of the pre-pit (reference numeral 600 in FIG. 1) is a 150 to 400 nm, more preferably 200- 300nm. By being 150-400 nm, the signal amplitude of a detection signal becomes large and the reading accuracy of a signal can be made high. Moreover, the said effect can be expressed more reliably by setting it as 200-300 nm.

  The average half-width W in the radial direction of the prepits is preferably 200 to 500 nm, and more preferably 250 to 450 nm. By being 200 to 500 nm, crosstalk in the inter-track direction is small, and a sufficient signal amplitude can be obtained. Note that the circumferential length (half-value width) of the prepit is appropriately set because it depends on information to be recorded.

The ratio (h ₁ / h ₂ ) between the average thickness h ₁ of the visible information recording layer 524 on the prepit convex portion 600A and the average thickness h ₂ of the visible information recording layer 524 on the prepit concave portion 600B is 0. It is preferable that the depth (h _p + h ₁ -h ₂ ) of the visible information recording layer on the concave portion of the prepit is 70 to 250 nm.

When “h ₁ / h ₂ ” and “h _p + h ₁ -h ₂ ” are in the above ranges, the surface on which the reflective layer 526 of the visible information recording layer 524 is formed is uneven enough to read laser light. And a good reproduction signal can be obtained. A more preferable range of “h ₁ / h ₂ ” is 0.2 to 0.8. The more preferable range of “h _p + h ₁ -h ₂ ” is 100 to 200 nm, and more preferably 120 to 180 nm.

Further, as shown in FIG. 2, it is preferable that the reflective layer 526 is formed along the visible information recording layer 524, and the average thickness _{t 1} of the reflective layer 526 on the convex portion 600A of the pre-pit, the recess of the pre-pit 600B The ratio (t ₁ / t ₂ ) to the average thickness t ₂ of the upper reflective layer is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1.

Note that the _h p, such as _{h 1} and _{h 2} can be determined from the AFM and transmission spectra and an ellipsometer. As another method, it can be obtained by observing a cross section of the completed optical disc with an SEM or the like.

  Further, as another aspect of the optical disc of the present invention, the optical disc has a reflective layer, the inner circumference of the visible information recording layer is larger than the inner circumference of the substrate and the reflective layer, and the inner circumference of the reflective layer and the visible Visible information is drawn on the substrate between the inner periphery of the information recording layer, and the concavo-convex shape of the stamper used in the step of molding the substrate is transferred to the visible information on the substrate. The aspect currently drawn by the uneven | corrugated shape formed is mentioned. With such an embodiment, the handleability can be improved. FIG. 23 is a top view of the optical disc 500 shown in FIG. 1 viewed from the second substrate 522 side. As shown in FIG. 23, “image recording surface” is drawn as visible information between the inner circumference 524A of the visible information recording layer 524 and the inner circumference 526A of the reflective layer 526. The user can recognize that the image can be recorded from the character information “image recording surface”.

As the visually recognizable information, the character string “image recording surface” shown in FIG. 23 is an example, and in the present invention, it is possible to identify that the surface having information visible to the user is the image recording surface. Any form of information may be used. For example, an arbitrary character string, a mark indicating a visible information recording layer, a line, a figure, and the like can be given. In other words, in the optical disc of the present invention, the user can easily identify that the surface having the visually recognizable information is the image recording surface, and it is possible to prevent erroneous use of the front and back of the optical disc. As a result, the handleability can be improved.
The height (depth) of the concavo-convex shape corresponding to the visually recognizable information is preferably 10 to 400 nm, more preferably 50 to 300 nm, from the viewpoint of improving the visibility.
Further, by setting the height (depth) of the concavo-convex shape to be the same as the height (depth) of the prepits or pregrooves, there is an advantage that it is easy to manufacture.

  In the present invention, the visible information is obtained by forming a concavo-convex shape corresponding to information to be drawn on the substrate on a stamper used for forming the substrate, and transferring the concavo-convex shape to the substrate. The concavo-convex shape is formed in a shape reversed left and right with respect to the shape to be transferred to the substrate, and the height (depth) is preferably 10 to 400 nm as described above, and is preferably 50 to 300 nm. More preferably.

  The region where the visible information is drawn can be located at a radius of 7.5 to 21 mm (preferably a radius of 13 to 20 mm, more preferably a radius of 14 to 18 mm).

  As described above, the optical disc of the present invention can be manufactured very easily because the visible information (uneven shape) can be transferred together with pre-pits and pre-grooves by a stamper when the substrate is formed.

  A substrate having pregrooves and prepits as described above can be formed using a stamper provided with grooves and irregularities for forming the above pregrooves and prepits. It is preferable that the average height of the protrusions among the unevenness is 150 to 400 nm. By using such a stamper, the optical disk of the present invention can be produced efficiently.

  As a process for manufacturing the stamper, a process substantially the same as that for manufacturing a normal CD-ROM or CD-R stamper can be employed. Specifically, a stamper can be manufactured by forming a photoresist film on a glass master, performing development, sputtering a metal such as nickel, and performing electrolysis.

  The structure of the optical disk of the present invention is not particularly limited as long as the above-described pregroove is formed and the structure has a visible information recording layer. 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.

Moreover, the optical disk of the present invention has the following configurations, for example.
(1) The first layer configuration is a configuration in which an information recording layer, a reflective layer, and an adhesive layer are sequentially formed on a first substrate, and a second substrate having a visible information recording layer is bonded onto the adhesive layer. It is.
(2) In the second layer configuration, an information recording layer, a reflective layer, a protective layer, and an adhesive layer are sequentially formed on a first substrate, and a second substrate having a visible information recording layer is formed on the adhesive layer. It is the structure which bonds together.
(3) The third layer configuration is such that an information recording layer, a reflective layer, a protective layer, an adhesive layer, and a protective layer are sequentially formed on a first substrate, and a visible information recording layer is provided on the protective layer. In this configuration, two substrates are bonded together.
(4) In the fourth layer configuration, an information recording layer, a reflective layer, a protective layer, an adhesive layer, a protective layer, and a protective layer are sequentially formed on the first substrate, and a visible information recording layer is formed on the protective layer. The second substrate having the structure is attached.
(5) In the fifth layer configuration, an information recording layer, a reflective layer, an adhesive layer, and a reflective layer are sequentially formed on a first substrate, and a visible information recording layer is provided on the reflective layer. It is the structure which bonds together.
(6) In the sixth layer configuration, an information recording layer, a reflective layer, and a protective layer are sequentially formed on the first substrate, while a visible information recording layer, a reflective layer, and a protective layer are formed on the second substrate. It is the structure which forms sequentially and bonds both protective layers through an adhesive layer.

The layer configurations of the above (1) to (6) are merely examples, and the layer configuration is not limited to the order described above, and a part thereof may be replaced. A part (except the visible information recording layer) may be omitted. Furthermore, each layer may be composed of one layer or a plurality of layers.
Hereinafter, the substrate and each layer will be described. In the following description, the first substrate and the second substrate may be collectively referred to simply as “substrate”.

  Especially, it is preferable to apply to the structure of DVD (In addition to DVD, DVD-R, DVD-RW, HD DVD etc. are included). That is, a bonded optical disk has a configuration in which at least an information recording layer is formed on one substrate and a visible information recording layer is formed on the surface of the other substrate on which a prepit is formed, and these are bonded.

  FIG. 1 is a partial cross-sectional view showing an example of the layer structure of an optical disc 500 of the present invention. The optical disc 500 includes a first laminated body 520 having an information recording layer 514 and a first reflective layer 516 in this order on a first substrate 512, and a second substrate 522 irradiated with laser light. A visible information recording layer 524 on which a visible image is recorded and a second stacked body 528 having a second reflective layer 526 in this order, and the first stacked body 520 and the second stacked body 528 are: The first reflective layer 516 and the second reflective layer 526 are bonded together with an adhesive layer 530 so as to face each other. A pregroove 610 and a prepit 600 are formed on the surface of the second substrate 522 where the visible information recording layer is formed. In the following, each layer and its forming method will be described by taking the layer configuration shown in FIG. 1 as an example.

(Information recording layer)
The information recording layer is a layer in which code information (coded information) such as digital information is recorded, and examples thereof include a dye type, a write-once type, a phase change type, and a magneto-optical type. It is preferable that

  Specific examples of the dye compound contained in the dye-type information recording layer include a cyanine dye, an oxonol dye, a metal complex dye, an azo dye, and a phthalocyanine dye, and among them, a phthalocyanine dye and an oxonol dye are preferable.

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

  Furthermore, the recording material is not limited to a dye, but a triazole compound, triazine compound, cyanine compound, merocyanine compound, aminobutadiene compound, phthalocyanine compound, cinnamic acid compound, viologen compound, azo compound, oxonol benzoxazole compound, benzotriazole compound Organic compounds such as these are also preferably used. Among these compounds, cyanine compounds, aminobutadiene compounds, benzotriazole compounds, and phthalocyanine compounds are particularly preferable.

  For the information recording layer, a recording material such as a dye is dissolved in a suitable solvent together with a binder and the like to prepare a coating solution. Next, the coating solution is applied on a substrate to form a coating film, and then dried. 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 can be formed by a method such as vapor deposition, sputtering, CVD, or solvent coating, but solvent coating is preferred.

  Examples of the solvent of the coating solution include esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; dimethylformamide and the like Amides; Hydrocarbons such as methylcyclohexane; Ethers such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; 2,2,3,3-tetra Fluorinated solvents such as fluoropropanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, etc. And the like can be mentioned recall ethers.

  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 an antioxidant, a UV absorber, a plasticizer, and a lubricant 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 a material for the information recording layer, 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 the amount. It is in the range.

  Examples of the solvent application method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. The information recording layer may be a single layer or a multilayer. The thickness of the information recording layer 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 can contain various anti-fading agents in order to improve the light resistance of the information recording layer. 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 Nos. 58-175893, 59-31194, 60-18387, 60-19586, 60-19588, 60-35054, 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, 60-47069, 68-209995, JP Listed in publications such as Nos. 4-25492, 1-38680, and 6-26028, German Patent No. 350399, and the Chemical Society of Japan, October 1992, page 1141 Can do.

  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.

  Specific examples of materials constituting the phase change type information recording layer include Sb—Te alloy, Ge—Sb—Te alloy, Pd—Ge—Sb—Te alloy, Nb—Ge—Sb—Te alloy, and 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 is preferably 10 to 50 nm, more preferably 15 to 30 nm.

  The above phase change type information recording layer can be formed by a vapor phase thin film deposition method such as a sputtering method or a vacuum deposition method.

(First substrate, second substrate)
The 1st board | substrate and 2nd board | substrate of the optical disk of this invention can be arbitrarily selected from the various materials currently used as a board | substrate of the conventional optical disk. Here, pregrooves and prepits are formed on the visible information recording layer side of the second substrate.

  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 viewpoint of moisture resistance, dimensional stability, price, and the like.

  The second substrate is manufactured through a step of manufacturing a substrate having prepits on the side on which the visible information recording layer is formed using the above-described stamper of the present invention. The height of the convex portion corresponding to the depth of the prepit can be controlled by adjusting the film thickness of the photoresist.

  The thickness of the first substrate and the second substrate is preferably 0.1 to 1.2 mm, and more preferably 0.2 to 1.1 mm. It is preferable that a groove or tracking servo signal is basically formed on the first substrate, and a substrate on which such a groove or tracking servo signal is formed is used for the second substrate. May be. The track pitch of the groove of the first substrate is preferably in the range of 280 to 900 nm, and more preferably in the range of 300 to 800 nm. The depth of the groove (groove depth) is preferably in the range of 15 to 200 nm, and more preferably in the range of 25 to 180 nm.

On the first substrate surface (the surface on which the grooves are formed (the surface on which the pits are formed in the case of ROM)), for the purpose of improving the flatness, improving the adhesive force, and preventing the alteration of the information recording layer, An undercoat layer 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 an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do.
The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably in the range of 0.01 to 10 μm.

  On the other hand, in the visible image drawn on the visible information recording layer, it is preferable to subject the second substrate to a roughening treatment in order to prevent reflection of surroundings due to specular reflection light.

  The surface roughening treatment method for the second substrate includes various methods and is not particularly limited, but any one of the following first to fifth surface roughening treatments is preferably applied.

(1) In the first roughening treatment, the visible information recording layer of the second substrate is formed on one surface with which the second substrate comes into contact using a stamper subjected to the roughening treatment. The side surface is roughened. Specifically, first, a roughening process is performed on a stamper used when manufacturing the second substrate. As a method of the roughening process, for example, a blasting process such as sandblasting is performed to obtain a desired roughness. Further, chemical treatment as described in the fifth roughening treatment may be performed. Then, this stamper is placed on the mold so that the roughened surface is in contact with the resin material of the second substrate, and is molded by a known method, whereby the second surface having the roughened surface only on one surface. The substrate is manufactured. In addition, as said "desired roughness", the maximum height (Rz) of the said surface is 0.3-5 micrometers, and the average length (RSm) of a roughness curve element is 10-10, for example. The thickness is preferably 500 μm.

(2) The second roughening treatment uses a molding die in which the roughening treatment is performed on one surface that contacts the second substrate after molding, and the visible information recording layer of the second substrate is The surface on the side to be formed is roughened. Specifically, a roughening process is performed on one main surface of the second substrate molding die. The surface roughening method is the same as in the case of the first surface roughening treatment. By using the mold and molding by a known method, the surface roughened only on one surface. A second substrate is produced.

(3) In the third roughening treatment, after the second substrate is manufactured, a resin in which fine particles are dispersed is applied to the surface on the side where the visible information recording layer is formed, and the resin is cured, The surface of the substrate on which the visible information recording layer is formed is roughened. As said resin, acrylate type ultraviolet curable resin, epoxy type, isocyanate type thermosetting resin, etc. can be used.

As the fine particles, inorganic fine particles such as SiO ₂ and Al ₂ O ₃ , polycarbonate, acrylic resin particles, and the like can be used. The volume average particle size of the fine particles is preferably 0.3 to 200 μm, and more preferably 0.6 to 100 μm. By adjusting the particle size and addition amount of the fine particles, the roughened surface can have a desired roughness.

(4) In the fourth roughening treatment, after the second substrate is manufactured, the surface on which the visible information recording layer is formed is subjected to a machining process so that the visible information recording layer of the second substrate is The surface on the side to be formed is roughened. As the machining process, various processes can be applied, but it is preferable to apply a blasting process such as sandblasting.

(5) In the fifth roughening treatment, after the second substrate is produced, the surface on which the visible information recording layer is formed is subjected to chemical treatment to form the visible information recording layer of the second substrate. The surface to be processed is roughened. As the chemical treatment, a process of etching by applying a solvent to one surface of the second substrate after molding or spraying with a spray can be applied. As the solvent, an organic solvent such as dimethylformamide is preferable, and in addition, an acidic solvent such as nitric acid, hydrochloric acid, and sulfuric acid can be used. The desired roughness can be obtained by adjusting the normality of the acidic solvent as described above or adjusting the coating time.

(First reflective layer, second reflective layer)
A first reflective layer and a second reflective layer are provided adjacent to the information recording layer and the visible information recording layer for the purpose of improving the reflectance during information reproduction. The light-reflective substance that is the material of the reflective layer is a substance having a high reflectivity with respect to laser light. Examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and 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 metals such as semimetals and stainless steels. These substances may be used alone or in combination of two or more or as an alloy. Among these, 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 metal, Al metal or alloys thereof. The reflective layer can be formed on the substrate or the information 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 a layer for bonding the first stacked body 520 and the second stacked body 528 in FIG. 1, and is located between the first reflective layer 516 and the second reflective layer 526. As an adhesive used for the adhesive layer, a known ultraviolet curable resin or the like can be used.

(Visible information recording layer)
As described above, the optical disc of the present invention has a visible information recording layer on the surface opposite to the information recording layer. The visible information recording layer records visible images (visible information) desired by the user, such as characters, figures, and patterns. Examples of visible images include disc titles, content information, content thumbnails, related patterns, design patterns, copyright information, recording date, recording method, recording format, barcodes, and the like.

  The visible image recorded in the visible information recording layer means a visually recognizable image, and includes all visually recognizable information such as characters (columns), designs, and figures. 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, sales 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 visible information recording layer only needs to be able to record image information such as characters, images, patterns, and the like so as to be visible by laser light irradiation. Considering that pits can be clearly formed, the visible information recording layer preferably contains a dye compound. As the constituent material, the dye described in the above-described information recording layer can be preferably used. In this case, considering the cost and the like, the visible information recording layer is preferably formed by spin coating using a coating solution containing a dye compound.

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

  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, fluoran compounds such as 3-methyl-propyl-6-methyl-7-anilinofluoran; and the like are preferable.

  The visible information recording layer can be formed by preparing a coating solution by dissolving the aforementioned 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 described above can be used. Other additives and coating methods are the same as those of the recording layer described above.

  The thickness of the visible information recording layer is preferably 0.01 to 2 μm, more preferably 0.05 to 1 μm, and still more preferably 0.1 to 0.5 μm.

Below, a protective layer is demonstrated.
(Protective layer)
A protective layer may be provided for the purpose of physically and chemically protecting the first reflective layer and the information recording layer.

Examples of materials used for the protective layer include inorganic substances such as ZnS, ZnS—SiO ₂ , SiO, SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N ₄ , thermoplastic resins, thermosetting resins, and UV curable materials. Organic substances such as resins can be mentioned.

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

  As described above, the optical disc of the present invention can be applied to a so-called read-only optical disc having a recording portion (pit) in which information reproducible by laser light is recorded on a first substrate. It is.

  Further, as a modification of the optical disk of the present invention, the configurations of FIGS. 21 and 22 can be given. In FIG. 21, a print area 702 is formed on the label surface, and an information area 704 and an image recording area (visible information recording layer) 706 are formed inside the disc (on the label surface forming surface side of the substrate 720) from the inner periphery side. It is a top view which shows the made structure. The partial sectional structure is as shown in FIG. 22, and an image recording area 706 and an information area 704 are formed between the substrate 710 and the substrate 720 from the outer peripheral side. A print region 702 is formed on the upper surface of the substrate 720. In the print area 702, for example, a product name or a manufacturer name is printed. An example of the printing method is screen printing. As shown in FIG. 21, by forming such a print region 702 at the innermost end, the innermost end of the optical disc is shielded, and the visual effect of the user can be enhanced.

  The information area 704 is an area where pre-grooves and pre-pits according to the present invention are formed. In the image recording area 706, a visible image as described above is drawn by laser light.

  Here, in FIG. 22, r0 that is the inner peripheral edge of the printing region 702 is preferably 8 to 21 mm, and r1 that is the outer peripheral edge is preferably 21 to 23 mm (where r0 <r1). The inner peripheral edge r2 of the information area 704 is preferably 19 to 22 mm, and the outer peripheral edge r3 is preferably 22 to 25 mm (where r2 <r3). Further, r3 which is the inner peripheral edge of the image recording area 706 is preferably 22 to 25 mm, and r4 which is the outer peripheral edge corresponds to the outermost periphery of the image recording area 706 (where r3 <r4).

[Image recording method]
Image recording on the visible information recording layer of the optical disc of the present invention is performed by irradiating the visible information recording layer with laser light on the optical disc of the present invention. In particular, once an image is formed, information relating to image recording is recorded in the pregroove, and based on the information recorded in the pregroove, the visible information recording layer is irradiated with laser light to additionally record the image. First, an optical disk recording apparatus used for recording on an optical disk according to the present invention will be described.

  As a method for recording information in the pregroove, a method for recording information in a normal DVD-R can be applied. In addition, the recorded information includes the radial position or polar coordinates of the imaged area, the date and time when the image was formed, the type of drive used for image formation, the laser power and the number of rotations when the image was formed, etc. Information such as formation conditions can be given.

(Optical disk recording device)
In the optical disc of the present invention, recording of an image on the visible information recording layer and recording of optical information on the information recording layer can be performed by, for example, one optical disc drive (recording apparatus) having a recording function on both layers. it can. When one optical disk drive is used in this way, after recording on one of the visible information recording layer and the information recording layer, the recording can be reversed and recording can be performed on the other layer.

  Even if an image is once recorded and the optical disk is taken out from the drive, if information relating to image recording is recorded on the optical disk, the visible information recording layer is irradiated with laser light based on the recorded information. Can be added.

  The optical disk of the present invention described above can be used particularly suitably for the following apparatuses and methods.

For example, an optical disc recording apparatus in which the above-described optical disc of the present invention is suitably used is
(1) An optical disc recording apparatus for recording information by irradiating a recording surface (for example, an information recording layer (recording layer)) of an optical disc with laser light, and an optical pickup for irradiating the optical disc with laser light An optical position in which the recording surface is formed on one surface and a visible information recording layer is formed on the other surface of the optical information recording layer; Is formed to control the optical pickup and the irradiation position adjusting means so that a visible image corresponding to image information is formed on the visible information recording layer of the optical disc when the optical pickup is set to face the optical pickup. Control means and a beam of laser light emitted by the optical pickup to the visible information recording layer when forming the visible image Beam spot control means for controlling the optical pickup so that the pot diameter is larger than the beam spot diameter of the laser beam irradiated by the optical pickup on the recording surface when information recording is performed. It is a feature.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. A visible image can be formed. When such a visible image is formed, the laser light is irradiated to a larger area while the optical disk is rotated once by increasing the beam spot diameter of the laser light applied to the visible information recording layer of the optical disk. The time required for forming a visible image can be shortened. In addition, the above-described optical disc of the present invention can record a good visible image by such a method.

Another aspect of the optical disk recording apparatus is:
(2) An optical disk recording apparatus for recording information by irradiating a recording surface of an optical disk with laser light, an optical pickup for irradiating the optical disk with laser light, and a laser beam applied to the optical disk by the optical pickup. An irradiation position adjusting means for adjusting the irradiation position and an optical disc in which the recording surface is formed on one surface and the visible information recording layer is formed on the other surface are set so that the visible information recording layer faces the optical pickup. 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 visible information recording layer of the optical disc, wherein the optical pickup records the visible information The intensity of the laser light applied to the layer is such that the visible information recording layer hardly changes based on the image information. Image forming control means for controlling the visible information recording layer to be either a second intensity that is greater than the first intensity or the second intensity at which the visible information recording layer changes, and a laser that is irradiated to the optical disk by the optical pickup Servo information that detects information about light and controls the optical pickup so that a desired laser beam is irradiated based on the detection result, and the image formation control means performs control based on the image information. Therefore, when the time when the intensity of the laser light emitted from the optical pickup is continuously the second intensity exceeds a certain time, the laser emitted from the optical pickup regardless of the content of the image information. Control is performed so that the intensity of the light becomes the first intensity for a predetermined time, and the servo means relates to the information about the laser beam irradiated at the first intensity. It is characterized by controlling the optical pickup based on the detection result.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. A visible image can be formed. When such a visible image is formed, even when the intensity of the laser light corresponding to the image data lasts for a long time as the second intensity for changing the visible information recording layer, the laser is used regardless of the image data. Since the visible light recording layer is irradiated with laser light having the first intensity that hardly changes for light control, laser light control based on the irradiation result can be performed. In addition, the above-described optical disc of the present invention can record a good visible image by such a method.

Another aspect of the optical disk recording apparatus is:
(3) An optical disk recording apparatus for recording information by irradiating a recording surface of an optical disk with laser light, an optical pickup that irradiates the optical disk with laser light, and a laser beam applied to the optical disk by the optical pickup. Irradiation position adjusting means for adjusting the irradiation position; and 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 recording surface of the optical disc, the optical pickup The intensity of the laser beam applied to the recording surface is a first intensity at which the recording surface hardly changes based on the image information, or the recording surface changes more than the first intensity. Image forming control means for controlling the optical disc to have any one of the above-mentioned intensities, and illuminating the optical disc by the optical pickup. Servo information for detecting information related to the laser light to be emitted and controlling the optical pickup so that desired laser light is irradiated based on the detection result, and the image formation control means includes the image information. Irradiation 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 the control based on The intensity of the emitted laser light is controlled to become the first intensity for a predetermined time, and the servo means controls the optical pickup based on the detection result of the information relating to the laser light irradiated with the first intensity. It is characterized by doing.

  According to this configuration, by irradiating the visible information recording layer of the optical disc 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. Can do. 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. In addition, the above-described optical disc of the present invention can record a good visible image by such a method.

Another aspect of the optical disk recording apparatus is:
(4) An optical disk recording apparatus for recording information by irradiating a recording surface of an optical disk with laser light, an optical pickup for irradiating the optical disk with laser light, and a laser beam applied to the optical disk by the optical pickup. An irradiation position adjusting means for adjusting the irradiation position and an optical disc in which the recording surface is formed on one surface and the visible information recording layer is formed on the other surface are set so that the visible information recording layer faces the optical pickup. The image pickup 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 visible information recording layer of the optical disc, and the optical disc is the optical disc recording apparatus. When the optical information is recorded on the optical disc, the surface of the optical disc facing the optical pickup In it the basis of whether the recording surface or is characterized by comprising 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 disc.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. A visible image can be formed. When the optical disc is set, the positional relationship between the optical pickup and the surface facing the optical pickup is adjusted according to whether the visible information recording layer or the recording surface is set to face the optical pickup. be able to. Therefore, when the recording surface is set to face the optical pickup and when the visible information recording layer is set to face the optical pickup, the distance between the optical pickup and the surface facing this 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. In addition, the above-described optical disc of the present invention can record a good visible image by such a method.

Another aspect of the optical disk recording apparatus is:
(5) An optical disc recording apparatus for recording information by irradiating a recording surface of an optical disc with laser light, an optical pickup for irradiating the optical disc with laser light, and laser light on the optical disc by the optical pickup. An irradiation position adjusting means for adjusting an irradiation position, and an optical disk in which the recording surface is formed on one surface and a visible information recording layer is formed on the other surface, and an optical disk in which a guide groove is spirally formed on the recording surface However, when the visible information recording layer is set so as to face the optical pickup, the laser light is irradiated along the guide groove based on the reflected light from the optical disk of the laser light irradiated by the optical pickup. Servo means for controlling the irradiation position adjusting means, and the irradiation position of the laser light along the guide groove by the servo means. Image forming control means for controlling laser light emitted from the optical pickup so that a visible image corresponding to image information is formed on the visible information recording layer of the optical disc while being moved. It is characterized by. In addition, the above-described optical disc of the present invention can record a good visible image by such a method.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. 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 disk recording apparatus is:
(6) An optical disk recording apparatus for recording information by irradiating a recording surface of an optical disk with laser light, an optical pickup for irradiating the optical disk with laser light, and a rotation driving means for rotating the optical disk; A clock signal output means for outputting a clock signal having a frequency corresponding to the rotational speed of the optical disk by the rotation driving means, and an optical disk in which the recording surface is formed on one surface and the visible information recording layer is formed on the other surface. Means for controlling the optical pickup so that a visible image corresponding to image information is formed on the visible information recording layer of the optical disc when the visible information recording layer is set to face the optical pickup; The laser beam emitted from the optical pickup based on the image information for each period of the clock signal by the signal output means. Image forming control means for controlling light; rotation detecting means for detecting that the optical disk has been rotated once from a predetermined reference position by the rotation driving means; and the visible image on the visible information recording layer of the optical disk. When the rotation detecting means detects that the optical disk has been rotated once from the predetermined reference position in a state in which the optical pickup is irradiated with the optical pickup to form the laser light from the optical pickup And an irradiation position adjusting means for moving the irradiation position by a predetermined amount in a predetermined radial direction of the optical disc set in the optical disc recording apparatus.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. A visible image can be formed. When this visible image is formed, laser light irradiation control for visible image formation is performed every period of the clock signal having a frequency corresponding to the rotation speed of the optical disk, that is, every time the optical disk rotates by a certain angle. A visible image having contents (for example, density) corresponding to the image data can be formed at a position for each fixed angle. In addition, the above-described optical disc of the present invention can record a good visible image by such a method.

Another aspect of the optical disk recording apparatus is:
(7) An optical disk recording apparatus for recording information by irradiating a recording surface of an optical disk with laser light, an optical pickup for irradiating the optical disk with laser light, and a rotation driving means for rotating the optical disk; A rotation detecting means for detecting that the optical disk is rotated once from a predetermined reference position by the rotation driving means; and an optical disk in which the recording surface is formed on one surface and the visible information recording layer is formed on the other surface. Image formation control for controlling the optical pickup so that a visible image corresponding to image information is formed on the visible information recording layer of the optical disc when the visible information recording layer is set to face the optical pickup. And a laser beam irradiated by the optical pickup to form the visible image on the visible information recording layer of the optical disc. When the rotation detecting unit detects that the optical disk has been rotated once from the predetermined reference position in the state where the optical pickup is performed, the irradiation position of the laser beam by the optical pickup is set in the optical disk recording apparatus. Irradiation position adjusting means for moving the optical disk by a predetermined amount in a predetermined radial direction, and the image formation control means is configured to provide the predetermined reference of the visible information recording layer of the optical disk rotated by the rotation driving means. In order to form the visible image from a position, the optical pickup is irradiated with a laser beam, while the irradiation position of the laser beam reaches the predetermined reference position of the optical disc from a position that is a predetermined amount ahead of the predetermined position. So that the laser beam for forming the visible image is not irradiated onto the region up to the reference position. It is characterized by controlling the up.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. 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 disc while rotating the optical disc, and the region immediately before the laser beam irradiation position returns to the reference position. The laser beam irradiation for forming a visible image is not performed. Therefore, the laser light irradiation position control is disturbed for some reason such as unstable rotation of the optical disk, the laser light is continuously irradiated from the reference position, the optical disk is rotated once, and the irradiation position passes through the reference position again. In other words, even if the laser beam irradiation position moves to a position that overlaps the position where the laser beam has already been irradiated later, the laser beam for forming a visible image is prevented from being irradiated to that position. As a result, the quality of the visible image formed can be prevented from deteriorating.

Another aspect of the optical disk recording apparatus is:
(8) An optical disc recording apparatus that records information by irradiating a recording surface of an optical disc with laser light, an optical pickup that irradiates the optical disc with laser light, and a laser beam applied to the optical disc by the optical pickup. An irradiation position adjusting means for adjusting the irradiation position; a disk identification means for obtaining disk identification information for identifying the type of the optical disk set in the optical disk recording apparatus; and the recording surface on one surface. When an optical disc on which a visible information recording layer is formed is set so that the visible information recording layer faces the optical pickup, a visible image corresponding to image information is formed on the visible information recording layer of the optical disc. Means for controlling the optical pickup and the irradiation position adjusting means, the disc identifying means Thus it is characterized by comprising an image forming control unit for controlling the optical pickup and the irradiation position adjusting means in accordance with the identified type of optical disc.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. 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 disk recording apparatus is:
(9) An optical pickup that irradiates a laser beam to the optical disc, a modulation unit that modulates information supplied from the outside, and a laser beam that is irradiated from the optical pickup according to information supplied from the modulation unit. In an optical disk recording apparatus comprising a laser beam control means for controlling, a visible image is formed on the visible information recording layer of an optical disk in which the recording surface is formed on one surface and the visible information recording layer is formed on the other surface. In the case, the prohibiting means for prohibiting the modulation by the modulating means with respect to image information supplied from the outside, and when the visible information recording layer of the optical disc is set to face the optical pickup, the modulating means The record is formed so that a visible image corresponding to the supplied unmodulated image information is formed on the visible information recording layer of the optical disc. It is characterized by comprising an image forming control means for controlling the laser light control means.

  According to this configuration, by irradiating the visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in the absorbance of the visible information recording layer, and corresponds to the image data. 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. Therefore, a data transfer configuration for recording information on a 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 disk recording apparatus is:
(10) An optical disk recording apparatus that records information by irradiating a recording surface of an optical disk with laser light, an optical pickup that irradiates the optical disk with laser light, and a laser beam applied to the optical disk by the optical pickup. An irradiation position adjusting means for adjusting the irradiation position and an optical disc in which the recording surface is formed on one surface and the visible information recording layer is formed on the other surface are set so that the visible information recording layer faces the optical pickup. 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 visible information recording layer of the optical disc. The formation control means controls the laser light emitted from the optical pickup in accordance with the gradation level indicated in the image information. It is characterized in that.

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

Another aspect of the optical disk recording apparatus is:
(11) An optical disc recording apparatus that records information by irradiating a recording surface of an optical disc with laser light, the rotating unit rotating the optical disc, and the optical disc rotated by the rotating unit from the one side An optical pickup that emits laser light and is movable in a substantially radial direction of the optical disc, and means for adjusting the level of laser light emitted from the optical pickup when forming a visible image on the visible information recording layer. Thus, based on the image data representing the visible image to be formed, the first intensity that hardly changes the recording layer and the visible information recording layer of the optical disc, or the visible information recording that hardly changes the recording layer. A laser beam emitted from the optical pickup so as to have one of the second intensities that change the color of the layer. And having a laser light level control means for adjusting the level of light.

  According to this apparatus, information can be recorded on the optical disc of the present invention by irradiating the recording layer with laser light in the same manner as before, and a visible image can be recorded on the visible information recording layer. 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 disk, the user needs to perform troublesome operations such as turning the optical disk over and resetting it. There is no.

  Also, the image forming method on the visible information recording layer of the optical disc of the present invention uses an optical disc recording apparatus having an optical pickup for recording information by irradiating the recording surface of the optical disc with a laser beam, and the recording surface of the optical disc Forming a visible image on a visible information recording layer formed on a surface opposite to the surface, wherein the irradiation position of the laser beam by the optical pickup is a predetermined spiral or concentric circumferential shape on the visible information recording layer The optical pickup irradiates the optical pickup so that a visible image corresponding to image information is formed on the visible information recording layer of the optical disc while moving along the path of An area including a predetermined number (a plurality) of adjacent paths belonging to each of fan-shaped portions obtained by dividing an optical disk into a plurality of units is defined as a unit area, and the visible image Shading of definitive the unit regions is characterized by controlling 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 visible information recording layer of the optical disc with laser light according to the image data, the reflectance changes like an image in accordance with the change in absorbance of the visible information 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 irradiation timing control can be performed in accordance with the gradation degree of each position (coordinate) on the visible information recording layer indicated in the image data, and the visible representation with gradation expression is made. An image can be formed.

A. Specific Configuration of the Optical Disc Recording Device The optical disc recording device is an optical disc recording device that records information by irradiating a recording surface of an optical disc with a laser beam. It has a function of forming a visible image corresponding to image data by irradiating the visible information recording layer of the optical disc having the visible information recording layer formed on the surface opposite to the surface with a laser beam. In such an apparatus, a visible image can be recorded not only on a visible information recording layer but also on a recording layer for recording normal digital data on an optical disk using a predetermined dye.

-Configuration of optical disc recording device-
FIG. 4 is a block diagram showing the configuration of the optical disk recording apparatus. As shown in the figure, this optical disk recording apparatus 100 is connected to a host personal computer (PC) 110, and includes an optical pickup 10, a spindle motor 11, an RF (Radio Frequency) amplifier 12, and a servo circuit 13. The decoder 15, the control unit 16, the encoder 17, the strategy circuit 18, the laser driver 19, the laser power control circuit 20, the frequency generator 21, the stepping motor 30, the motor driver 31, and the motor controller 32. A PLL (Phase Locked Loop) circuit 33, a FIFO (First In First Out) memory 34, a drive pulse generator 35, and a buffer memory 36.

  The spindle motor 11 is a motor that rotationally drives an optical disk D that is a target for recording data, and the number of rotations is controlled by a servo circuit 13. In the optical disc recording apparatus 100 according to the present embodiment, recording or the like is performed by a CAV (Constant Angular Velocity) method, and therefore the spindle motor 11 rotates at a constant angular velocity set by an instruction from the control unit 16 or the like. It is supposed to be.

  The optical pickup 10 is a unit that irradiates the optical disk D rotated by the spindle motor 11 with laser light, and its configuration is shown in FIG. As shown in the figure, the optical pickup 10 includes a laser diode 53 that emits a laser beam B, a diffraction grating 58, an optical system 55 that focuses the laser beam B on the surface of the optical disc D, and a light receiving device that receives reflected light. An element 56 is provided.

  In the optical pickup 10, the laser diode 53 emits a laser beam B having an intensity corresponding to the drive current when supplied with the drive current from the laser driver 19 (see FIG. 4). The optical pickup 10 separates the laser beam B emitted from the laser diode 53 into a main beam, a preceding beam, and a succeeding beam by a diffraction grating 58, and these three laser beams are polarized beam splitter 59, collimator lens 60, 1 / The light is condensed on the surface of the optical disc D through the four-wavelength plate 61 and the objective lens 62. Then, the three laser beams reflected on the surface of the optical disc D are transmitted again through the objective lens 62, the quarter wavelength plate 61, and the collimator lens 60, reflected by the polarization beam splitter 59, and passed through the cylindrical lens 63. The light is incident on the light receiving element 56. The light receiving element 56 outputs a received signal to the RF amplifier 12 (see FIG. 4), and the received light signal is supplied to the control unit 16 and the servo circuit 13 via the RF amplifier 12.

  The objective lens 62 is held by a focus actuator 64 and a tracking actuator 65 so as to be movable in the optical axis direction of the laser beam B and the radial direction of the optical disc D. Each of the focus actuator 64 and the tracking actuator 65 moves the objective lens 62 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 13 (see FIG. 4). The servo circuit 13 generates a focus error signal and a tracking error signal based on the light reception signal supplied via the light receiving element 56 and the RF amplifier 12, and moves the objective lens 62 as described above to perform focus control. And tracking control.

  The optical pickup 10 has a front monitor diode (not shown). When the laser diode 53 emits laser light, a current is generated in the front monitor diode that receives the emitted light, and the current is It is supplied from the optical pickup 10 to the laser power control circuit 20 shown in FIG.

  The RF amplifier 12 amplifies the EFM (Eight to Four Modulation) modulated RF signal supplied from the optical pickup 10, and outputs the amplified RF signal to the servo circuit 13 and the decoder 15. The decoder 15 performs EFM demodulation on the EFM-modulated RF signal supplied from the RF amplifier 12 during reproduction to generate reproduction data.

  The servo circuit 13 is supplied with an instruction signal from the control unit 16, an FG pulse signal having a frequency corresponding to the rotation speed of the spindle motor 11 supplied from the frequency generator 21, and an RF signal from the RF amplifier 12. The servo circuit 13 performs rotation control of the spindle motor 11 and focus control and tracking control of the optical pickup 10 based on these supplied signals. As a driving method of the spindle motor 11 when recording information on the recording surface (information recording layer) of the optical disk D or when forming a visible image on the visible information recording layer (see FIG. 1) of the optical disk D, the optical disk D is used. Either a method of driving 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. The optical disk recording apparatus 100 described below employs the CAV method, and the servo circuit 13 rotates the spindle motor 11 at a constant angular velocity designated by the control unit 16.

  The buffer memory 36 supplies information (hereinafter referred to as recording data) to be recorded on the recording surface of the optical disc D and information corresponding to a visible image to be formed on the visible information recording layer of the optical disc D (hereinafter referred to as “recording data”) supplied from the host PC 110. Image data). The recording data stored in the buffer memory 36 is output to the encoder 17, and the image data is output to the control unit 16.

  The encoder 17 performs EFM modulation on the recording data supplied from the buffer memory 36 and outputs it to the strategy circuit 18. The strategy circuit 18 performs time axis correction processing or the like on the EFM signal supplied from the encoder 17 and outputs the result to the laser driver 19.

  The laser driver 19 drives a laser diode 53 (see FIG. 5) of the optical pickup 10 according to a signal modulated according to the recording data supplied from the strategy circuit 18 and the control of the laser power control circuit 20.

  The laser power control circuit 20 controls the laser power emitted from the laser diode 53 (see FIG. 5) of the optical pickup 10. Specifically, the laser power control circuit 20 controls the laser driver 19 so that a laser beam having a value that matches the target value of the optimum laser power indicated by the control unit 16 is emitted from the optical pickup 10. The laser power control by the laser power control circuit 20 performed here is controlled so that laser light having a target intensity is emitted from the optical pickup 10 using the current value supplied from the front monitor diode of the optical pickup 10. Feedback control.

  In the FIFO memory 34, the image data supplied from the host PC 110 and stored in the buffer memory 36 is supplied via the control unit 16 and sequentially stored. Here, the image data stored in the FIFO memory 34, that is, the image data supplied from the host PC 110 to the optical disc recording apparatus 100 includes the following information. This image data is data for forming a visible image on the surface of the disk-shaped optical disc D. As shown in FIG. 6, each of n pieces on a large number of concentric circles centering on the center O of the optical disc D is shown. Information indicating the degree of gradation (shading) is described for each coordinate (indicated by a black dot in the figure). The image data includes coordinate points P11, P12... P1n in which information indicating the gradation of these coordinates belongs to the innermost circle, coordinates P21, P22... P2n belonging to one of the outer circles, Further, the data indicating the gradation of each coordinate point up to the coordinate Pmn of the outermost circle in the order of the coordinates belonging to one outer circle is described, and the FIFO memory 34 has such polar coordinates. Information indicating the degree of gradation of each coordinate is supplied in the order as described above. FIG. 6 is a diagram schematically illustrating the positional relationship between the coordinates, and the actual coordinates are arranged more densely than illustrated. When the host PC 110 creates image data to be formed on the photosensitive surface of the optical disc D in a commonly used bitmap format or the like, 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 110 to the optical disc recording apparatus 100.

  When a visible image is formed on the visible information recording layer of the optical disc D based on the image data supplied as described above, a clock signal for image recording is supplied from the PLL circuit 33 to the FIFO memory 34. It is like that. Each time the clock pulse of the image recording clock signal is supplied, the FIFO memory 34 outputs information indicating the gradation degree of one coordinate accumulated first to the drive pulse generator 35. Yes.

  The drive pulse generator 35 generates a drive pulse for controlling the irradiation timing of the laser light emitted from the optical pickup 10. Here, the drive pulse generation unit 35 generates a drive pulse having a pulse width corresponding to information indicating the degree of gradation for each coordinate supplied from the FIFO memory 34. For example, when the degree of gradation at a certain coordinate is relatively large (when the density is large), a drive pulse with a light level (second intensity) pulse width increased is generated as shown in the upper part of FIG. For coordinates with a relatively small degree of furnishing, as shown in the lower part of FIG. 7, a drive pulse with a reduced write level pulse width is generated. Here, the light level is a power level at which the visible information recording layer changes when the visible information recording layer of the optical disc D is irradiated with the laser power at that level, and the reflectance is clearly changed. When a simple driving pulse is supplied to the laser driver 19, a light level laser beam is emitted from the optical pickup 10 for a time corresponding to the pulse width. Therefore, when the gradation level is large, the laser light of the light level is irradiated for a longer time, and the reflectance changes in a larger area in the unit area of the visible information recording layer of the optical disc D. This region is visually recognized as a region having a high density. In the present embodiment, the gradation shown in the image data is expressed by varying the length of the region whose reflectance is changed per unit region (unit length) in this way. Note that the servo level (first intensity) is a power level at which the visible information recording layer hardly changes when the visible information recording layer of the optical disc D is irradiated with the laser power of that level, and the reflectance needs to be changed. It is only necessary to irradiate the servo level laser light without irradiating the light level laser light to the region where there is no light.

  The drive pulse generator 35 generates a drive pulse in accordance with the information indicating the gradation for each coordinate as described above, and performs laser power control by the laser power control circuit 20, focus control by the servo circuit 13, and When it is necessary to perform the tracking control, a light level pulse or a servo level pulse for a very short period is inserted regardless of the information indicating the gradation level. For example, as shown in the upper part of FIG. 8, in order to express a visible image according to the gradation of a certain coordinate in the image data, it is necessary to irradiate a laser beam having a light level for a period of time T1. When the time T1 is longer than a predetermined servo cycle ST for controlling the laser power, the servo off-pulse (SSP1) for a very short time t after the servo cycle ST elapses from the time when the write level pulse is generated. ) Is inserted. On the other hand, as shown in the lower part of FIG. 8, when it is necessary to irradiate a laser beam having a servo level for a period longer than the servo cycle ST in order to represent a visible image according to the gradation of a certain coordinate in the image data, A servo on pulse (SSP2) is inserted after the servo cycle ST has elapsed after the level pulse is generated.

  As described above, the laser power control by the laser power control circuit 20 is based on the current (intensity of the irradiated laser light) supplied from the front monitor diode that receives the laser light emitted from the laser diode 53 (see FIG. 5) of the optical pickup 10. (The current having a value corresponding to the current value). More specifically, as shown in FIG. 9, the laser power control circuit 20 samples and holds a value corresponding to the intensity of the irradiated laser beam received by the front monitor diode 53a as described above (S201, S202). . Then, when irradiation is performed with the light level as a target value, that is, when a light level drive pulse (see FIGS. 7 and 8) is generated, the light is supplied from the control unit 16 based on the sample and hold result. Laser power control is performed so that the laser light of the light level target value is irradiated (S203). Further, when irradiation is performed with the servo level as a target value, that is, when a servo level drive pulse (see FIGS. 7 and 8) is generated, it is supplied from the control unit 16 based on the result of sample and hold. Laser power control is performed so that laser light of the target servo level value is irradiated (S204). Therefore, when the write 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 on pulse are output as described above regardless of the contents of the image data. SSP2 is forcibly inserted so that the laser power can be controlled for each level as described above.

  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 13. That is, the tracking control and focus control are based on the RF signal received by the light receiving element 56 (see FIG. 5) of the optical pickup 10, that is, the return light (reflected light) from the optical disk D of the laser light emitted from the laser diode 53. Done. Here, FIG. 10 shows an example of a signal received by the light receiving element 56 when the laser beam is irradiated. As shown in the figure, the reflected light when the light level laser beam is irradiated includes an element of a peak portion K1 when the laser beam rises and a shoulder portion K2 where the level becomes constant thereafter. The portion shown is considered to be energy used for image formation of the visible information recording layer. And the energy used for image formation of such a visible information recording layer does not always become a stable value, but it is possible to change according to various situations. Therefore, it is conceivable that the shape of the shaded portion in the figure changes each time, that is, the reflected light of the light level laser light is not always stable and can be obtained with a lot of noise and the like. There is a risk that accurate focus control and tracking control may be hindered. Therefore, as described above, when the light level laser beam is continuously irradiated for a long time, the reflected light of the servo level laser beam cannot be obtained, and accurate focus control and tracking control cannot be performed. End up.

  Therefore, by inserting the servo off-pulse SSP1 as described above, the reflected light of the servo level laser light can be periodically acquired, and focus control and tracking control are executed based on the acquired reflected light. It is. When forming a visible image on the visible information recording layer of the optical disc D, unlike when recording on the recording surface, it is not necessary to trace along a pre-groove (guide groove) formed in advance. Therefore, in this embodiment, the target value of tracking control is a fixed value (a constant offset voltage is set). Such a control method can be applied not only when image information is formed on the visible information recording layer but also when image information is formed on the recording surface. That is, if a material that changes not only the reflectance but also the color development when irradiated with laser light is used for the recording surface (recording layer), an image can be formed on the recording surface as well as the visible information recording layer. . When a visible image is formed on the recording surface in this way, the original data recording cannot be performed on the portion where the visible image is formed. Therefore, the data recording area and the visible image forming area are separated in advance. Is preferred.

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

  Returning to FIG. 4, the PLL circuit (signal output means) 33 multiplies the FG pulse signal having a frequency corresponding to the rotational speed of the spindle motor 11 supplied from the frequency generator 21, and uses it for the visible image formation described later. Output clock signal. The frequency generator 21 outputs an FG pulse signal having a frequency corresponding to the number of spindle revolutions using a counter electromotive current obtained by the motor driver of the spindle motor 11. For example, as shown in the upper part of FIG. 11, when the frequency generator 21 generates eight FG pulses while the spindle motor 11 makes one revolution, that is, the optical disk D makes one revolution, the lower part of FIG. As shown in FIG. 4, the PLL circuit 33 outputs a clock signal (for example, a frequency of 5 times the FG pulse signal and 40 high-level pulses during one rotation of the optical disk D) obtained by multiplying the FG pulse, that is, the spindle motor 11. To output a clock signal having a frequency corresponding to the rotational speed of the optical disk D rotated. A clock signal obtained by multiplying the FG pulse signal in this way is output from the PLL circuit 33 to the FIFO memory 34, and the gradation of one coordinate is added to the clock signal every cycle, that is, every time the disk D rotates by a certain angle. The data shown is output from the FIFO memory 34 to the drive pulse generator 35. 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 11 is a motor with sufficiently stable rotational drive capability. In this case, a crystal oscillator may be provided in place of the PLL circuit 33 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 D.

  The stepping motor 30 is a motor for moving the optical pickup 10 in the radial direction of the optical disc D set on the optical disc D. The motor driver 31 rotates the stepping motor 30 by an amount corresponding to the pulse signal supplied from the motor controller 32. The motor controller 32 generates a pulse signal according to the movement amount and the movement direction according to the movement start instruction including the movement direction and movement amount in the radial direction of the optical pickup 10 instructed from the control unit 16, and the motor driver 31. Output to. The stepping motor 30 moves the optical pickup 10 in the radial direction of the optical disc D, and the spindle motor 11 rotates the optical disc D with respect to the optical disc D, whereby the laser light irradiation position of the optical pickup 10 is set to various positions on the optical disc D. It can be moved, and these components constitute the irradiation position adjusting means.

  The control unit 16 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 on the recording surface of the optical disc D and the image forming process on the visible information recording layer of the optical disc D are centrally controlled. What has been described above is the configuration of the optical disc recording apparatus 100 according to the present embodiment.

B. Operation of Optical Disc Recording Device Next, the operation of the optical disc recording device 100 configured as described above will be described. As described above, the optical disc recording apparatus 100 can record information such as music data supplied from the host PC 110 on the recording surface of the optical disc D, and can record information on the visible information recording layer of the optical disc D. A visible image corresponding to the image data supplied from the host PC 110 can be formed. The operation of the optical disc recording apparatus 100 capable of performing processing such as information recording and visible image formation will be described below with reference to FIGS.

  First, when the optical disc D is set in the optical disc recording apparatus 100, the control unit 16 controls the optical pickup 10 and the like, and the surface of the set optical disc D facing the optical pickup 10 is an optical disc of any format. To detect. 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 such information is not recorded, it is not recognized as an optical disc.

  Here, for example, when a land pre-pit signal or pre-record signal is detected in the case of DVD-R or ADIP is detected in the case of DVD + R from the set optical disk D, the recording surface is opposed to the optical pickup 10. The optical disk D is determined to be set on the recording surface, and the control unit 16 performs control for recording the recording data supplied from the host PC 110 on the recording surface (step Sa2). Since the control for recording the recording data performed here is the same as that of the conventional optical disk recording apparatus (DVD-R or DVD + R), description thereof is omitted.

  On the other hand, when a pre-pit signal indicating that the optical disc is drawable is detected from the set optical disc D, it is determined that the optical disc D is set so that the visible information recording layer faces the optical pickup 10. The control unit 16 determines whether or not the disc ID of the set optical disc D can be acquired (step Sa3). The disc ID of the optical disc D can be mounted in the pre-pit signal. Further, for example, as shown in FIG. 14, a visible image corresponding to information obtained by encoding the disc ID is described along the circumference of the outermost peripheral portion of the optical disc D on the visible information recording layer side. In FIG. 14, as shown in the drawing, the disc ID is changed to the visible information recording layer of the optical disc D by forming a reflective region 301a and a non-reflective region 301b having a length corresponding to the code along the circumference of the outermost peripheral portion. It is described in. The control unit 16 obtains the disk ID from the reflected light by tracing the irradiation position of the laser light of the optical pickup 10 along the outermost circumference of the optical disk D.

  Therefore, when the reflective area 301a and the non-reflective area 301b corresponding to the disk ID as described above are not formed on the outermost peripheral portion of the visible information recording layer, the optical disk D generally has no visible information recording layer. It can be discriminated that the optical disc is a CD-R, DVD-R or the like. When the disk ID cannot be acquired in this way, the control unit 16 determines that the optical disk D 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 D, the host PC 110 waits until an image formation instruction including image data is received (step Sa5). Performs initialization control for forming a visible image on the visible information recording layer of the optical disc D (step Sa6). More specifically, the control unit 16 controls the servo circuit 13 so that the spindle motor 11 is rotated at a predetermined angular velocity, or moves the optical pickup 10 to the initial position on the innermost peripheral side in the radial direction of the optical disc D. The instruction for sending is sent to the motor controller 32 to drive the stepping motor 30.

  In the initialization control for image formation, the control unit 16 irradiates the visible information recording layer of the optical disc D with a laser beam having a larger beam spot diameter than when recording information on the recording surface. A target value for focus control can also be instructed to the servo circuit 13.

  The focus control content when the target value as described above is instructed will be described in more detail as follows. As described above, the focus control by the servo circuit 13 is performed based on the signal output from the light receiving element 56 of the optical pickup 10. When recording information on the recording surface of the optical disc D, the servo circuit 13 is focused so that circular return light (A in the figure) is received at the centers of the four areas 56a, 56b, 56c, and 56d of the light receiving element 56 shown in FIG. The actuator 64 (see FIG. 5) is driven. That is, the focus actuator 64 is driven so that (a + c) − (b + d) = 0 when the received light amounts of the areas 56a, 56b, 56c, and 56d are a, b, c, and d.

  On the other hand, when a visible image is formed on the visible information recording layer of the optical disc D, as described above, focus control is performed so that the visible information recording layer is irradiated with laser light having a diameter larger than that during information recording on the recording surface. Is done. When the shape of the return light received by the light receiving element 56 shown in FIG. 15 is an elliptical shape (B or C in the figure), the spot size of the laser light is larger than that in the case of the circle A, so the servo circuit 13 drives the focus actuator 64 so that the elliptical return light is received by the light receiving element 56. That is, the focus actuator 64 is driven so as to satisfy (a + c) − (b + d) = α (α is not 0). Therefore, in the present embodiment, the control unit 16 and the servo circuit 13 constitute beam spot control means.

  As described above, in the initialization control for visible image formation described above, the control unit 16 instructs the servo circuit 13 to set α (not 0), so that a laser having a larger spot diameter than that when recording information on the recording surface. The visible information recording layer of the optical disc D can be irradiated with light. Thus, when a visible image is formed on the visible information recording layer of the optical disc D, the following effects can be obtained by irradiating laser light having a larger spot diameter than that when recording information on the recording surface. That is, in this embodiment, when forming a visible image, laser light is irradiated while rotating the optical disc D, as in the case of recording information on the recording surface. Therefore, by increasing the beam spot diameter of the laser light, a visible image can be formed on the entire area of the visible information recording layer of the optical disc D in a shorter time. The reason for this will be described with reference to FIG. As schematically shown in the figure, when comparing the case where the beam spot diameter BS of the laser beam to be irradiated is large and small, the area of the region to be image-formed when the optical disk D is rotated once is the beam. When the spot diameter BS is large, it becomes larger. For this reason, when the beam spot diameter BS is small, the optical disk D has to be rotated more in order to make the entire area the target of image formation (in the example shown in the figure, when the beam spot diameter BS is large, it is 4 rotations, and when 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 a laser beam having a larger spot diameter than that during information recording when forming a visible image.

  Further, in the initialization control for image formation, the control unit 16 sets the target value of each level to the laser power so that the laser light of the write level and the servo level corresponding to the acquired disk ID is emitted from the optical pickup 10. The control circuit 20 is instructed. That is, the ROM of the control unit 16 stores a target value to be set as a write level and a servo level for each of a plurality of types of disk IDs. The control unit 16 stores the write level and the write level corresponding to the acquired disk ID. The servo level target values are read out, and these target values are instructed to the laser power control circuit 20.

  The power target value is set in accordance with the disk ID as described above for the following reason. That is, the characteristics of the dye of the visible information recording layer may be different depending on the type of the optical disc D, and when the characteristics are different, the characteristic that the reflectance changes naturally when the laser beam is irradiated to what extent is naturally changed. become. For this reason, even if the visible information recording layer of a certain optical disc D is irradiated with laser light at a certain light level, and the reflectance of the irradiated region can be sufficiently changed, When the visible light recording layer is irradiated with laser light having the same light level, the reflectance of the irradiated region cannot always be changed. Therefore, in the present embodiment, the target values of the write level and the servo level that allow accurate image formation are obtained in advance by experiment for each optical disk corresponding to each of various disk IDs as described above. Then, by storing the obtained target value in the ROM in association with each disk ID, optimal power control can be performed according to the characteristics of the visible information recording layer of various optical disks D as described above. I can do it.

  When the initialization control as described above is performed by the control unit 16, a process for actually forming a visible image on the visible information recording layer of the optical disc D is performed. As shown in FIG. 13, first, the control unit 16 transfers the image data supplied from the host PC 110 via the buffer memory 36 to the FIFO memory 34 (step Sa7). Then, the control unit 16 determines from the FG pulse signal supplied from the frequency generator 21 whether the predetermined reference position of the optical disc D rotated by the spindle motor 11 has passed the laser light irradiation position of the optical pickup 10. Is determined (step Sa8).

  Here, a method for detecting whether or not the predetermined reference position and the laser beam irradiation position have passed the position will be described with reference to FIGS. 17 and 18. As shown in FIG. 17, the frequency generator 21 outputs a predetermined number (eight in the illustrated example) of FG pulses while the spindle motor 11 rotates once, that is, while the optical disk D rotates once. Accordingly, the control unit 16 outputs a reference position detection pulse by synchronizing one of the FG pulses supplied from the frequency generator 21 with the rising timing of the reference pulse, and then makes one rotation from the reference position detection pulse. A reference position detection pulse signal for outputting a reference position detection pulse is generated in synchronization with the rising timing of the minute number (eighth in the illustrated example) pulse. By generating such a reference position detection pulse, it is possible to detect that the time when the pulse is generated is the timing at which the laser light irradiation position of the optical pickup 10 has passed the reference position of the optical disc D. That is, as shown in FIG. 18, the laser beam irradiation position of the optical pickup 10 at the timing when the first reference position detection pulse is generated is indicated by the thick line in the figure (the optical pickup 10 is movable in the radial direction, so the irradiation position is If the reference position detection pulse generated after one rotation is generated, the laser light irradiation position of the optical pickup 10 is naturally indicated by a thick line in the figure. In position. In this way, the radial line to which the laser beam irradiation position belongs becomes the reference position at the timing at which the reference position detection pulse is first generated, and the control unit 16 is generated each time the optical disk D rotates as described above. It is possible to detect that the irradiation position of the laser light has passed the reference position of the optical disc D based on the reference position detection pulse signal. In the figure, the alternate long and short dash line shows an example of the movement trajectory of the irradiation position of the laser beam from the generation of a reference position detection pulse to the generation of the next reference position detection pulse.

  After receiving the image formation instruction from the host PC 110, when it is detected that the reference position of the optical disc D has passed the laser light irradiation position by the above-described method, the control unit 16 sets 1 to the variable R indicating the rotation speed. After the increment (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, R is an odd number in step Sa10. It will be determined. When it is determined that R is an odd number in this way, the control unit 16 performs control for irradiating the visible information recording layer of the optical disc D with the laser light from the optical pickup 10 to form a visible image (step Sa11). . More specifically, the control unit 16 receives the above reference position detection pulse and outputs each unit so as to sequentially output the image data from the FIFO memory 34 in synchronization with the clock signal output from the PLL circuit 33. Control. By this control, as shown in FIG. 19, every time a clock pulse is supplied from the PLL circuit 33, the FIFO memory 34 outputs information indicating the gradation of one coordinate to the drive pulse generator 35, and the drive pulse The generation unit 35 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 19. As a result, the optical pickup 10 irradiates the visible information recording layer of the optical disc D with the laser light at the light level for a time corresponding to the gradation of each coordinate, and the reflectance of the irradiated region changes, so that FIG. A visible image as shown can be formed.

  As schematically shown in the figure, the optical disk D is rotated by the spindle motor 11, so that the laser beam irradiation position of the optical pickup 10 is one cycle of the clock signal (the rising edge of the next pulse from the rising edge of the pulse). During the period until the timing), it moves along the circumference by the area indicated by C in the figure. By changing the time during which the laser beam is irradiated at the light level while the laser beam irradiation position passes through the region C according to the gradation level as described above, the gradation level varies depending on the region C as shown in the figure. Accordingly, the reflectance of different areas can be changed. In this way, by controlling the irradiation time of the light level laser light when passing through each region C according to the gradation of each coordinate, a visible image corresponding to the image data is applied to the visible information recording layer of the optical disc D. It can be formed.

  As described above, when the control for executing the formation of the visible image by the laser light irradiation controlled according to the image data is executed, the process of the control unit 16 returns to Step Sa7, and the image data supplied from the buffer memory 36 Is transferred to the FIFO memory 34. Then, it is detected whether or not the laser light irradiation position of the optical pickup 10 has passed through the reference position of the optical disc D, and when it is detected that the reference position has been passed, 1 is incremented to R. As a result, when R becomes an even number, the control unit 16 controls each unit of the apparatus so as to stop the visible image formation by the laser light irradiation control as described above (step Sa12). More specifically, the FIFO memory 34 is controlled not to output information indicating the gradation of each coordinate to the drive pulse generator 35 in synchronization with the clock signal supplied from the PLL circuit 33. That is, after the control unit 16 forms a visible image by irradiating the visible information recording layer of the optical disc D with a light level laser beam, the control unit 16 continues to rotate the visible information recording layer during the next rotation of the optical disc D. Control is performed so as not to irradiate laser light for changing the reflectance.

  When the laser beam irradiation for forming the visible image is stopped in this way, the control unit 16 instructs the motor controller 32 to move the optical pickup 10 to the outer peripheral side in the radial direction by a predetermined amount (step Sa13). In response to the instruction, the motor controller 32 drives the stepping motor 30 via the motor driver 31, whereby the optical pickup 10 is moved to the outer peripheral side by a predetermined amount.

  Here, the predetermined amount by which the optical pickup 10 is moved in the radial direction of the optical disc D may be appropriately determined according to the beam spot diameter BS (see FIG. 16) irradiated from the optical pickup 10 as described above. That is, when a visible image is formed on the visible information recording layer of the disc-shaped optical disc D, the laser beam irradiation position of the optical pickup 10 can be moved on the surface of the optical disc D with almost no gap to form a higher quality image. It is necessary to realize. Therefore, if the unit movement amount of the optical pickup 10 in the radial direction as described above is substantially the same as the beam spot diameter BS of the irradiation laser light with respect to the optical disc D, the laser light can be emitted on the surface of the optical disc D with almost no gap. Irradiation is possible, and higher-quality image formation is possible. In some cases, an area larger than the irradiated beam spot diameter may be colored due to various factors such as the properties of the visible information recording layer. In such a case, considering the width of the colored area, adjacent colored areas The unit movement amount may be determined so as not to overlap. In this embodiment, since the beam spot diameter BS is larger than that during recording on the recording surface (for example, about 20 μm), the control unit 16 reduces the diameter of the optical pickup 10 by substantially the same length as the beam spot diameter BS. The motor controller 32 is controlled to move in the direction, and the stepping motor 30 is driven. The stepping motor 30 in recent years can control the movement amount in units of 10 μm by using the μ step technology, and the optical pickup 10 can be controlled in units of 20 μm using the stepping motor 30 as described above. Moving in the radial direction is sufficiently feasible.

  When the control for moving the optical pickup 10 by a predetermined amount in the radial direction is performed as described above, the control unit 16 is configured to irradiate the laser beam at the light level so as to change the light level value of the target laser beam. The changed light level value to be targeted is instructed to the laser power control circuit 20 (step Sa14). In the present embodiment, a CAV method in which a laser beam is irradiated while rotating an optical disk D while maintaining a constant angular velocity is adopted as a method for forming a visible image. When moved to, the linear velocity increases. Therefore, when the optical pickup 10 is moved in the radial direction (outer peripheral side) in this way, the target value of the light level is changed to be larger than that at that time as described above, whereby the linear velocity is changed. Even if this changes, it is possible to irradiate the laser power with such intensity that the reflectivity of the visible information recording layer of the optical disc D can sufficiently change.

  As described above, when the movement control in the radial direction of the optical pickup 10 and the control for changing the target value of the light level are executed, the control unit 16 performs unprocessed image data, that is, the drive pulse generation unit 35 for forming a visible image. It is determined whether or not there is image data not supplied to the image. If there is no image data, the process is terminated.

  On the other hand, if there is unprocessed image data that has not been supplied to the motor controller 32, the process returns to step Sa7 to continue the process for visible image formation. That is, image data is transferred from the control unit 16 to the FIFO memory 34 (step Sa7), and it is determined whether or not the irradiation position of the laser beam has passed the reference position of the optical disc D (step Sa8). When the reference position is passed, the variable R indicating the number of rotations is incremented by 1 (step Sa9), and it is determined whether or not the incremented R is an odd number (step Sa10). Here, when R is an odd number, the control unit 16 controls each part of the apparatus so that the laser beam irradiation for forming a visible image as described above is performed. When R is an even number, the visible image is displayed. Is stopped (servo level laser light is irradiated), and control such as the above-described movement control of the optical pickup 10 in the radial direction and change of the light level target value is performed. That is, when the control unit 16 performs laser light irradiation (including the light level) for image formation on the optical disc D during a certain round, laser light irradiation for image formation is performed during the next round. Is controlled so that the optical pickup 10 is controlled to move in the radial direction during the rotation. In this way, by performing control for moving the optical pickup 10 during the lap when image formation is not performed, control for changing the light level target value, and the like, the irradiation position, the power value of the laser light to be irradiated, etc. No image is formed while the angle fluctuates, and laser beam irradiation for image formation can be executed after the irradiation position and the intensity of the laser beam 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 10 as described above.

  What has been described above is the main operation of the optical disc recording apparatus 100. According to the optical disc recording apparatus 100, the light used for recording information on the recording surface without newly installing printing means or the like. Using each part of the apparatus such as the pickup 10 as much as possible, the visible information recording layer of the optical disc D on which the visible information recording layer is formed is irradiated with laser light to form a visible image corresponding to the image data. it can.

  In this embodiment, the laser light irradiation timing is set based on the clock signal generated using the FG pulse generated according to the rotation of the spindle motor 11, that is, the clock signal generated according to the rotation amount of the optical disc D. Since the control is performed, it is possible to grasp the laser beam irradiation position in the optical disc recording apparatus 100 without acquiring position information or the like from the optical disc D side. Therefore, according to the optical disc recording apparatus 100, there is no restriction that the optical disc D subjected to special processing such as forming a pre-groove (guide groove) in the visible information recording layer has to be used. A visible image corresponding to the image data can be formed even on a visible information recording layer on which no image is formed in advance.

  Next, recording of information (digital information) on the information recording layer will be described. When the information recording layer is a dye type, first, laser light is irradiated from a laser pickup while rotating the above-mentioned unrecorded optical disk at a predetermined recording linear velocity. By this irradiation light, the dye of the information recording layer absorbs the light and the temperature rises locally, and a desired pit is generated and its optical characteristics are changed to record information.

The recording waveform of the laser beam may be a pulse train or one pulse when one pit is formed. The ratio to the actual recording length (pit length) is important.
The pulse width of the laser beam 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 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 further increased. preferable. Further, when the recording linear velocity is doubled, the preferable range of the laser beam power is ^21/2 times, respectively.

  In order to increase the recording density, the NA of the objective lens used for the pickup is preferably 0.55 or more, and more preferably 0.60 or more.

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

On the other hand, the case where the information recording layer is a phase change type will be described. In the case of the phase change type, it is composed of the above-described material, and the phase change between the crystalline phase and the amorphous phase can be repeated by laser light irradiation.
At the time of information recording, a concentrated laser light pulse is irradiated for a short time to partially melt the phase change recording layer. The melted portion is rapidly cooled by heat diffusion and solidified to form an amorphous recording mark. When erasing, the recording mark portion is irradiated with laser light, heated to a temperature lower than the melting point of the information recording layer and higher than the crystallization temperature, and cooled to crystallize the recording mark in an amorphous state. Return to the unrecorded state.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.

[Example 1]
Using polycarbonate resin as a raw material, a substrate (thickness 0.6 mm) having spiral guide grooves (grooves) was produced by injection molding. The guide groove had a depth of 130 nm, a half width of 300 nm, and a track pitch of 0.74 μm. A coating solution (1) prepared by dissolving 1.50 g of “Dye A” represented by the following chemical formula in 100 ml of 2,2,3,3-tetrafluoro-1-propanol was prepared, and this coating solution was used as a guide groove on the substrate. An information recording layer (average thickness: 80 μm) was formed by spin coating on the formation surface side. Next, a silver reflective layer was formed on the information recording layer by sputtering to produce a first disk.

  A prepit is formed in a region having a radius of 21 mm to a radius of 23 mm, and a pregroove is formed at a position of a radius of 23 mm to a radius of 24 mm. A stamper having a mirror surface outside the radius of 24 mm is substantially the same as that for producing a normal stamper as described below. In this way, it was produced. First, a photoresist was formed on a glass master by spin coating and baked. Thereafter, in response to the signal generated from the formatter by the laser beam recorder, the photoresist was irradiated only to the region having a radius of 21 mm to 23 mm, and then the beam was continuously irradiated to form a pregroove and developed. A stamper was produced by sputtering nickel on the substrate and electrifying.

  Next, in order to form a visible information recording layer, a substrate having a thickness of 0.6 mm was produced by injection molding using the stamper. Table 1 below shows the depth and half width of the pregroove formed by the stamper transfer, and the depth and half width of the 3T prepit.

  Prepared by dissolving 1.40 g of “Dye B” represented by the following chemical formula and 0.60 g of “Dye C” represented by the following chemical formula in 100 ml of 2,2,3,3-tetrafluoro-1-propanol. The coating liquid (2) was applied to the substrate by a spin coating method to form a visible information recording layer having a thickness of 0.1 μm. The innermost radius of the visible information recording layer forming region is as shown in Table 1 below. Further, a silver reflective layer was formed with a thickness of 80 nm on the visible information recording layer by a sputtering method, and a second disk was produced.

On the reflective layer of the first disk, UV curable resin Dicure Clear SD640 (manufactured by Dainippon Ink & Chemicals, Inc.) was discharged as an adhesive for bonding the two disks, and the reflective layer surface of the second disk After pasting the side with the side on which the adhesive on the first disc was discharged, press the second disc from the side, spread the UV curable resin, rotate it at high speed, and shake off the excess adhesive with centrifugal force An adhesive layer having a uniform film thickness was formed from the inner periphery to the outer periphery. In order to cure the adhesive, ultraviolet light was irradiated through the second disk, and the adhesive was cured to produce an optical disk. The ultraviolet lamp used at this time was a high-pressure mercury lamp, and the ultraviolet irradiation amount was 0.3 J / cm ² .

(Examples 2 and 3)
An optical disk was manufactured in the same manner as in Example 1 except that the depth of the pregroove and prepit, the half width in the radial direction or the circumferential direction, the inner diameter of the visible information recording layer, and the like were changed as shown in Table 1 below.

  The pregroove, prepit depth, and half width were obtained by measuring the substrate surface with AFM.

<Evaluation of optical disc>
The optical discs of Examples 1 to 3 were reproduced at a laser wavelength of 660 nm using a DDU1000 manufactured by Pulstec Industrial Co., Ltd., and the reflectance and the degree of modulation (I3 / Itop, I11 / Itop) were evaluated. Specifically, a disk drive device (DDU1000, manufactured by Pulstec Industrial Co., Ltd., laser wavelength = 660 nm, aperture ratio = 0.65) was used. The results are shown in Table 1 below.

  For the optical discs of Examples 1 to 3, after the image was once formed, information on the formation region at that time was recorded in the pregroove. Thereafter, this information was read out with a laser beam, and an image was recorded again based on the data. As a result, the image could be additionally recorded in a desired place without overlapping the initially recorded image.

From the results shown in Table 1, it was found that the optical disk of the example had sufficient reflectivity and push-pull signal for tracking along the pre-groove, and had a signal quality sufficient for information recording. . Further, as described in [0181], since information related to drawing is recorded in the pregroove, it was confirmed that additional writing is possible based on the information.

It is a fragmentary sectional view which shows the layer structure of the optical disk of this invention. It is a fragmentary sectional view which shows the layer structure of the board | substrate of the optical disk of this invention, a visible information recording layer, a reflection layer, and the shape of a prepit. It is a top view of the optical disk of the present invention. It is a block diagram which shows the structure of an example of the optical disk recording device which can handle the optical disk of this invention. It is a figure which shows the structure of the optical pick-up which is a component of the said optical disk recording device. It is a figure for demonstrating the content of the image data used in order to form a visible image with respect to the visible information recording layer of the said optical disk by the said optical disk recording device. It is a figure for demonstrating the irradiation control content of the laser beam for expressing the contrast of an image, when the said optical disk recording device forms a visible image with respect to the visible information recording layer of the optical disk of this invention. It is a figure for demonstrating the control method of the laser beam when the said optical disk recording device forms a visible image with respect to the visible information recording layer of the said optical disk. It is a figure for demonstrating the laser power control content by the laser power control circuit which is a component of the said optical disk recording device. It is a figure which shows the return light of the laser beam irradiated to the visible information recording layer of the said optical disk from the optical pick-up of the said optical disk recording device. It is a figure which shows the FG pulse produced | generated according to the rotation amount of a spindle motor by the frequency generator 21 which is a component of the said optical disk recording device, and the clock signal produced | generated based on the said FG pulse. 4 is a flowchart for explaining the operation of the optical disc recording apparatus. 4 is a flowchart for explaining the operation of the optical disc recording apparatus. It is a figure which shows disc ID recorded on the visible information recording layer of the said optical disc. It is a figure which shows the shape of the return light of the laser beam received by the light receiving element of the said optical pick-up of the said optical disk recording device. It is a figure for demonstrating the size of the beam spot diameter of the laser beam with which the said optical pick-up of the said optical disk recording device irradiates the said visible information recording layer of the said optical disk. It is a figure for demonstrating the method to detect that the laser beam irradiation position of the said optical disk recording device passed the reference | standard position of the said optical disk. It is a figure for demonstrating the method to detect that the laser beam irradiation position of the said optical disk recording device passed the reference position of the said optical disk. 4 is a timing chart for explaining the operation of the optical disc recording apparatus when a visible image is formed by irradiating a visible information recording layer of the optical disc with a laser beam. It is a figure which shows the visible information recording layer of the said optical disk irradiated with the laser beam by the said optical disk recording device. It is a top view in case the optical disk of the present invention has a printing area or the like. It is a fragmentary sectional view in case the optical disk of this invention has a printing area | region. It is the figure which looked at the optical disk shown in FIG. 1 from the 2nd board | substrate side.

Explanation of symbols

10 ... Optical pickup 11 ... Spindle motor (rotational drive means)
DESCRIPTION OF SYMBOLS 12 ... RF amplifier 13 ... Servo circuit 16 ... Control part 17 ... Encoder 18 ... Strategy circuit 19 ... Laser driver 20 ... Laser power control circuit 21 ... Frequency generator 30 ... Stepping motor 31 ... Motor driver 32 ... Motor controller 33 ... PLL circuit 34 ... FIFO memory 35 ... drive pulse generator 36 ... buffer memory 53 ... laser diode 53a ... front monitor diode 56 ... light receiving element 64 ... focus actuator 65 ... tracking actuator 100 ... optical disk recording device 270 ... chucking unit 271 ... adapter 280 ... Drive mechanism 320 ... Encoder D ... Optical disc 500 ... Optical disc 512 ... First substrate 514 ... Information recording layer 516 ... First reflective layer 520 ... First laminate 522 ... Second substrate 524 ... Visible information recording Layer 526: second reflective layer 528: second laminate 530 ... adhesive layer 600 ... prepit 610 ... pregroove

Claims (7)

An optical disc having a substrate and a visible information recording layer formed on the substrate and capable of recording visible information by irradiation with laser light,
An optical disc, wherein a pregroove is formed on a surface of the substrate on the visible information recording layer side.   2. The optical disc according to claim 1, further comprising prepits formed on a surface of the substrate on the visible information recording layer side.   The substrate has a reflective layer, the inner circumference of the visible information recording layer is larger than the inner circumference of the substrate and the reflective layer, and the substrate between the inner circumference of the reflective layer and the inner circumference of the visible information recording layer Visible information is drawn on the top, and the visible information on the substrate is drawn by an uneven shape formed by transferring an uneven shape of a stamper used in the step of forming the substrate. The optical disc according to claim 1.   4. The optical disc according to claim 3, wherein the area where the visible information is drawn is located at a radius of 7.5 to 21 mm.   The optical disk according to claim 1, wherein the pre-groove is formed on an inner peripheral side of a region where the visible information recording layer is formed.   3. The optical disc according to claim 1, wherein the visible information recording layer is formed on a region where the pregroove is formed.   The optical disk according to any one of claims 1 to 6, wherein an image is formed by irradiating the visible information recording layer with a laser beam, and then information relating to image recording is recorded in the pregroove, and the pregroove is recorded. An image recording method, wherein an image is additionally recorded by irradiating the visible information recording layer with a laser beam based on the information recorded on the recording medium.

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