JP2007287188A - Optical information recording medium design method, substrate for optical information recording medium and optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide optical disks having little dispersion in characteristics such as reflectance and recording sensitivity for individual disks. <P>SOLUTION: The depth h1 of a first pre-groove 12 is set so that a first information recording layer 22 satisfies a target reflectance based on an absorbance of a first pigment used for the first information recording layer 22, especially a first absorbance in the wavelength of a laser beam 32 to be used. The depth h2 of a second pre-groove is set so that a second information recording layer 28 satisfies a target reflectance based on an absorbance of a second pigment used for the second information recording layer 28, especially a second absorbance in the wavelength of the laser beam 32 to be used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a design method of a heat mode type optical information recording medium capable of writing (recording) and reading (reproducing) information using a laser beam, a substrate for an optical information recording medium, and an optical information recording medium.

  Conventionally, an optical information recording medium (optical disc) capable of recording information by laser light is known. Such optical disks include those having one information recording layer and those having two information recording layers.

  A first optical disc having one information recording layer includes a substrate having a pregroove formed on the surface, a reflective layer formed along the surface of the substrate, an information recording layer formed on the reflective layer, And a protective layer formed on the information recording layer.

  A second optical disc having two information recording layers includes a substrate having a first pregroove formed on a surface thereof, a translucent reflective layer formed along irregularities on the surface of the substrate, and the translucent reflective layer. A first information recording layer formed on the first information recording layer, an intermediate layer formed on the first information recording layer and having irregularities formed on the surface, and a second layer formed along the irregularities on the surface of the intermediate layer. It has an information recording layer, a reflective layer formed on the second information recording layer, and a protective layer formed on the reflective layer (see, for example, Patent Documents 1 to 3). The reflective layer is formed along the unevenness of the intermediate layer, whereby the unevenness of the reflective layer functions as the second pregroove of the second information recording layer.

  In addition to the formation of address pits for address detection, the pre-groove of the first optical disc and the first pre-groove and the second pre-groove of the second optical disc described above, the servo control of the spindle motor, the tracking control of the pickup, Servo pre-pits for focus control are formed.

  In addition, there is an example in which the pregroove of the first optical disc or the first pregroove and the second pregroove of the second optical disc are wobbled (see, for example, Patent Document 4). By wobbling, sector management information such as sector addresses can be given, and rotation control information at the time of recording can be obtained by reproducing the wobbled pregroove, so dedicated address pits and servo prepits can be obtained. It is unnecessary to provide the data pits, and the data writing efficiency can be improved by the amount of these address pits and servo pre-pits. In addition, there is an advantage that a method effective at the time of continuous data writing such as CLV rotation control can be adopted.

Japanese Patent Laid-Open No. 2005-4808 Japanese Patent Laid-Open No. 10-283682 JP-A-8-203125 Japanese Patent Laid-Open No. 9-219024

  By the way, when a dye is used for the information recording layer, the dye is formed by spin coating, but the reflectance and recording sensitivity of the information recording layer differ depending on the absorbance of the coated dye at the wavelength of the laser beam. Therefore, when an optical information recording medium is manufactured, there is a problem that the reflectance and recording sensitivity of the information recording layer vary from one optical information recording medium to another depending on the type of dye applied.

  The present invention has been made in consideration of such problems, and a method for designing an optical information recording medium with little variation in characteristics such as reflectance and recording sensitivity for each optical information recording medium, and a substrate for an optical information recording medium And an optical information recording medium.

  A method for designing an optical information recording medium according to the first aspect of the present invention includes a substrate having a groove and a dye recording layer formed on the substrate, and irradiating the dye recording layer with laser light. In a method for designing an optical information recording medium for recording and / or reproducing information, at least a target reflectance of the optical information recording medium based on the absorbance of the dye used in the dye recording layer at the wavelength of the laser light The groove depth is set so as to satisfy the above.

  Thus, an optical information recording medium with little variation in characteristics such as reflectance can be manufactured for each optical information recording medium, and the yield of the optical information recording medium can be improved and the development period can be shortened.

  In the first aspect of the present invention, from the first correlation between the absorbance and the reflectance and the second correlation between the depth of the groove and the reflectance, the absorbance and the groove at the target reflectance are calculated. A third correlation with the depth may be obtained, and the depth of the groove may be set based on the third correlation.

  Next, a method for designing an optical information recording medium according to a second aspect of the present invention includes a substrate having a groove and a dye recording layer formed on the substrate, and the dye recording layer is irradiated with laser light. In the method of designing an optical information recording medium for recording and / or reproducing information, at least the target of the optical information recording medium is based on the absorbance of the dye used in the dye recording layer at the wavelength of the laser light. The groove depth is set so as to satisfy the recording sensitivity.

  Accordingly, an optical information recording medium with little variation in characteristics such as recording sensitivity can be manufactured for each optical information recording medium, and the yield of the optical information recording medium can be improved and the development period can be shortened.

  In the second aspect of the present invention, from the first correlation between the absorbance and the recording sensitivity and the second correlation between the groove depth and the recording sensitivity, the absorbance and the groove at the target recording sensitivity are calculated. A third correlation with the depth may be obtained, and the depth of the groove may be set based on the third correlation.

  Next, a third method for designing an optical information recording medium according to the present invention includes a substrate having a groove and a dye recording layer formed on the substrate, and the dye recording layer is irradiated with laser light. In the method for designing an optical information recording medium for recording and / or reproducing information, the target of the optical information recording medium is determined based on the absorbance of the dye used in the dye recording layer at the wavelength of the laser light. The depth of the groove is set so as to satisfy the reflectance and the target recording sensitivity.

  Thereby, an optical information recording medium with little variation in characteristics such as reflectance and recording sensitivity can be manufactured for each optical information recording medium, and the yield of the optical information recording medium can be improved and the development period can be shortened. .

  In the third aspect of the present invention, from the first correlation between the absorbance and the reflectance and the second correlation between the depth of the groove and the reflectance, the absorbance at the target reflectance and the groove A third correlation with the depth is obtained, and the absorbance and the groove at the target recording sensitivity are obtained from the fourth correlation between the absorbance and the recording sensitivity and the fifth correlation between the depth of the groove and the recording sensitivity. A first correlation of the groove is set based on the third correlation, and a second depth of the groove is set based on the sixth correlation. An intermediate value between the first depth and the second depth may be set as the groove depth.

  In the first to third aspects of the invention described above, the optical information recording medium has a substrate on which the groove is formed, and the recording layer and the groove are viewed from the direction in which the laser beam is irradiated. They may be arranged in this order.

  Next, the optical information recording medium substrate according to the fourth aspect of the present invention is designed by the above-described optical information recording medium designing method according to the first to third aspects of the present invention. Accordingly, an optical information recording medium with little variation in characteristics such as reflectance and recording sensitivity can be manufactured for each optical information recording medium, and the yield of the optical information recording medium can be improved and the development period can be shortened. .

  Next, an optical information recording medium according to the fifth aspect of the present invention is designed by the above-described optical information recording medium designing method according to the first to third aspects of the present invention. Accordingly, an optical information recording medium with little variation in characteristics such as reflectance and recording sensitivity can be manufactured for each optical information recording medium, and the yield of the optical information recording medium can be improved and the development period can be shortened. .

  As described above, according to the optical information recording medium design method, the substrate for optical information recording medium, and the optical information recording medium according to the present invention, characteristic variations such as reflectance and recording sensitivity vary for each optical information recording medium. Therefore, it is possible to manufacture an optical information recording medium with a small amount of light, improve the yield of the optical information recording medium, and shorten the development period.

  Embodiments of an optical information recording medium designing method according to the present invention will be described below with reference to FIGS.

  First, as shown in FIG. 1, the first optical disc 10A manufactured by the design method according to the first embodiment includes a first substrate 14 having a first pregroove 12 formed on the surface, and a first substrate 14 having a first surface on the surface. The second substrate 18 on which the two pregrooves 16 are formed has a configuration in which the intermediate substrate 20 is bonded.

  That is, as shown in FIG. 2, the first information recording layer 22 is formed on the surface of the first substrate 14 along the unevenness of the first pregroove 12, and the semi-transparent reflection is formed on the first information recording layer 22. Layer 24 is formed.

  As shown in FIG. 3, a reflective layer 26 is formed on the surface of the second substrate 18 along the irregularities of the second pregroove 16, and a second information recording layer 28 is formed on the reflective layer 26. A barrier layer 30 is formed on the second information recording layer 28.

  Then, when the first substrate 14 and the second substrate 18 are bonded together, as shown in FIG. 1, the first information recording layer 22 formed on the first substrate 14 and the first information recording layer 22 formed on the second substrate 18 are formed. The two information recording layers 28 are opposed to each other, and further, the first optical disk 10A is configured by bonding the first substrate 14 and the second substrate 18 with the intermediate layer 20 interposed therebetween.

  When recording information on the first information recording layer 22, the recording laser beam 32 is irradiated in the direction from the end surface 14 a of the first substrate 14 toward the first information recording layer 22, and the laser beam 32 is irradiated with the first laser beam 32. Information (pits) is recorded by forming an image on the information recording layer 22. At this time, information is recorded in a portion of the first information recording layer 22 corresponding to the groove 34 of the first pre-groove 12. As the recording laser beam 32, a semiconductor laser beam having an oscillation wavelength in the range of 600 nm to 700 nm (preferably 620 to 680 nm, more preferably 630 to 660 nm) is used.

  When information is recorded on the second information recording layer 28, the recording laser beam 32 is irradiated in the direction from the end surface 14a of the first substrate 14 toward the second information recording layer 28, and the laser beam 32 is emitted from the second information recording layer 28 to the second information recording layer 28. Information (pits) is recorded by forming an image on the information recording layer 28. At this time, information is recorded in a portion of the second information recording layer 28 corresponding to the land 36 of the second pregroove 16.

  Therefore, the information recorded in the first information recording layer 22 and the information recorded in the second information recording layer 28 are provided by interposing the intermediate layer 20 between the first information recording layer 22 and the second information recording layer 28. Information interference can be prevented, and a good recording / reproducing signal can be obtained by the first information recording layer 22 and the second information recording layer 28.

  By the way, when a dye is used for the first information recording layer 22 and the second information recording layer 28, the dye is formed by spin coating, but the first information recording layer depends on the absorbance of the applied dye at the wavelength of the laser beam 32. 22 and the second information recording layer 28 have different reflectivities. Therefore, when the first optical disc 10A is manufactured, there is a problem that the reflectance of the first information recording layer 22 and the second information recording layer 28 varies for each first optical disc 10A depending on the kind of the applied dye.

  Therefore, the design method according to the first embodiment is based on the absorbance of the first dye used in the first information recording layer 22, particularly the first absorbance at the wavelength of the laser beam 32 used. The depth h1 of the first pregroove 12 is set so that the one information recording layer 22 satisfies the target reflectance (hereinafter referred to as the target reflectance). Further, based on the absorbance of the second dye used in the second information recording layer 28, particularly the second absorbance at the wavelength of the laser beam 32 used, the second information recording layer 28 satisfies the target reflectance. The depth h2 of the second pregroove is set.

  Here, as the first dye, for example, a dye obtained by mixing an oxonol dye represented by the following chemical formula (Chemical Formula 1) and an oxonol dye represented by the following chemical formula (Chemical Formula 2) at a ratio of 90:10 is used. . Further, as the second dye, for example, an oxonol dye represented by the following chemical formula (Formula 1) is used.

  Specifically, the design method according to the first embodiment will be described with reference to FIG.

  First, in step S1 of FIG. 4, the correlation (first correlation) between the first absorbance of the first dye used in the first information recording layer (the wavelength of the laser beam used, for example, absorbance at 650 nm) and the reflectance. Relationship). As shown in FIG. 5, the first correlation has a relationship in which the reflectance decreases as the first absorbance increases.

  Thereafter, in step S2 of FIG. 4, a correlation (second correlation) between the depth of the first pregroove and the reflectance is obtained. As shown in FIG. 6, the second correlation has a relationship in which the reflectance decreases as the depth of the first pregroove increases.

  Thereafter, in step S3 of FIG. 4, from the first correlation and the second correlation, the correlation between the first absorbance at the target reflectance (for example, 16%) and the depth of the first pregroove (third correlation). Ask for. As shown in FIG. 7, the third correlation has a relationship in which the depth of the first pregroove decreases as the first absorbance increases.

  In step S4 in FIG. 4, the first pregroove depth h1 is set based on the first absorbance and the third correlation of the first dye used.

  On the other hand, the depth of the second pregroove is set by taking the following steps.

  That is, first, in step S5 of FIG. 4, the correlation between the second absorbance of the second dye used in the second information recording layer (the wavelength of the laser beam used, for example, absorbance at 650 nm) and the reflectance (first 11 correlation). As shown in FIG. 8, the eleventh correlation has a relationship in which the reflectance decreases as the second absorbance increases.

  Thereafter, in step S6 of FIG. 4, a correlation between the depth of the second pregroove and the reflectance (a twelfth correlation) is obtained. As shown in FIG. 9, the twelfth correlation has a relationship in which the reflectance decreases as the depth of the second pregroove increases.

  Thereafter, in step S7 of FIG. 4, from the eleventh correlation and the twelfth correlation, the correlation between the second absorbance at the target reflectance (for example, 16%) and the depth of the second pregroove (the thirteenth correlation). Ask for. As shown in FIG. 10, the thirteenth correlation has a relationship in which the depth of the second pregroove decreases as the second absorbance increases.

  In step S8 of FIG. 4, the second pregroove depth h2 is set based on the second absorbance of the second dye used and the thirteenth correlation.

  As described above, after the depth h1 of the first pregroove and the depth h2 of the second pregroove are determined, the manufacturing process of the first optical disc 10A shown in FIG. 11 is entered.

  In this manufacturing process, first, in step S101 of FIG. 11, a first stamper for manufacturing the first substrate 14 is manufactured. In this case, the first original plate to be the first stamper is selectively etched to produce a first stamper having irregularities on the surface. For example, the first stamper is manufactured by performing high-precision mastering by cutting with a DUV (wavelength 330 nm or less, deep ultraviolet) laser or EB (electron beam) on the first original plate.

  At this time, when the first substrate 14 is formed by, for example, injection molding or extrusion molding of a resin material with the completed first stamper, the surface of the first substrate 14 is set in step S4 of FIG. The first stamper is manufactured by performing mastering on the first original plate so that the first pregroove 12 having the depth h1 is formed.

  Further, in step S102 of FIG. 11, a second stamper for producing the second substrate 18 is produced. In this case, the second original plate to be the second stamper is selectively etched to produce a second stamper having irregularities on the surface. For example, the second stamper is manufactured by performing high-precision mastering on the second original plate by cutting with a DUV (wavelength of 330 nm or less, deep ultraviolet) laser or EB (electron beam).

  At this time, when the second substrate 18 is formed by, for example, injection molding or extrusion molding of a resin material with the completed second stamper, the surface of the second substrate 18 is set in step S8 in FIG. The second stamper is manufactured by performing mastering on the second original plate so that the second pregroove 16 having the depth h2 is formed.

  Thereafter, in step S103 of FIG. 11, the first substrate 14 is manufactured by injection molding a resin material such as polycarbonate on the first stamper. At this time, the unevenness of the first stamper is transferred to the surface of the first substrate 14, and the first pregroove 12 having the depth h1 set in step S4 of FIG. 4 is formed.

  Further, in step S104 of FIG. 11, the second substrate 18 is manufactured by injection molding or extrusion molding of a resin material such as polycarbonate with respect to the second stamper. At this time, the unevenness of the second stamper is transferred to the surface of the second substrate 18, and the second pregroove 16 having the depth h2 set in step S8 in FIG. 4 is formed.

  In the above example, the first substrate 14 and the second substrate 18 are manufactured by injection molding or extrusion molding of a resin material such as polycarbonate. However, the first substrate 14 having a flat surface as described below is used. The first pregroove 12 and the second pregroove 16 may be formed by forming a pregroove layer on the surface of the second substrate 18.

  As a material for the pregroove layer, a mixture of at least one monomer (or oligomer) of monoester, diester, triester and tetraester of acrylic acid and a photopolymerization initiator can be used. The formation of the pre-groove layer is, for example, when the first substrate 14 is viewed, a mixed liquid composed of the above acrylate ester and a polymerization initiator is applied on the first stamper, and the first substrate 14 is further applied on the coating liquid layer. After mounting, the coating layer is cured by irradiating ultraviolet rays through the first substrate 14 or the first stamper to fix the first substrate 14 and the coating layer. Next, by peeling the first substrate 14 from the first stamper, it is possible to obtain the first substrate 14 with the pregroove layer having the first pregroove 12 formed on the surface. The same applies to the second substrate 18. By using the second stamper, it is possible to obtain the second substrate 18 having the pregroove layer having the second pregroove 16 formed on the surface thereof.

  Thereafter, in step S <b> 105 of FIG. 11, the first information recording layer 22 is formed on the surface of the first substrate 14, and then the translucent reflective layer 24 is formed on the first information recording layer 22.

  Further, in step S106 of FIG. 11, the reflective layer 26 is formed on the surface of the second substrate 18, then the second information recording layer 28 is formed on the reflective layer 26, and further on the second information recording layer 28. The barrier layer 30 is formed.

  Thereafter, in step S107 of FIG. 11, the first substrate 14 and the second substrate 18 are bonded together. At this time, the first information recording layer 22 formed on the first substrate 14 and the second information recording layer 28 formed on the second substrate 18 are opposed to each other, and further, the first substrate 14 and the second substrate The intermediate layer 20 is interposed between the two layers 18 and 18. By this bonding, the first optical disc 10A is completed.

  Next, a second optical disc 10B produced by the design method according to the first embodiment will be described with reference to FIG. The second optical disk 10B has substantially the same configuration as the first optical disk 10A described above, but the surface of the second substrate 18 is a flat surface, and instead, the interface between the intermediate layer 20 and the barrier layer 30 is uneven. The adhesive layer 48 is formed between the reflective layer 26 and the second substrate 18, and the unevenness is reflected on the surface of the reflective layer 26 and functions as the second pregroove 16 of the second information recording layer 28. Is different in that it is interposed.

  Here, the manufacturing process of the second optical disc 10B will be described with reference to FIGS.

  First, in step S201 in FIG. 13, a first stamper for producing the first substrate 14 is produced. Since this step S201 performs the same processing as step S101 of FIG. 11 described above, the duplicated explanation is omitted.

  Further, in step S202 of FIG. 13, a second stamper for producing the second substrate 18 is produced. At this time, when the second substrate 18 is formed, for example, by injection molding a resin material with the completed second stamper, the second stamper is manufactured so that the surface of the second substrate 18 becomes a flat surface.

  Further, in step S203 of FIG. 13, a third stamper for forming irregularities on the surface of the intermediate layer 20 is produced. In this case, the third original plate to be the third stamper is selectively etched to produce a third stamper having irregularities on the surface. For example, the third stamper is manufactured by performing high-precision mastering on the third original plate by cutting with a DUV (wavelength of 330 nm or less, deep ultraviolet) laser or EB (electron beam).

  At this time, when the unevenness is formed on the surface of the intermediate layer 20 by the completed third stamper and the barrier layer 30, the second information recording layer 28, and the reflective layer 26 are further formed on the intermediate layer 20, the reflective layer 26 A third stamper is produced by mastering the third original plate so that the second pregroove 16 having the depth h2 set in step S8 of FIG.

  Thereafter, in step S204 of FIG. 13, the first substrate 14 is manufactured by injection molding or extrusion molding of the resin material with respect to the first stamper. At this time, the unevenness of the first stamper is transferred to the surface of the first substrate 14, and the first pregroove 12 having the depth h1 set in step S4 of FIG. 4 is formed.

  Further, in step S205 of FIG. 13, the second substrate 18 is manufactured by injection molding or extrusion molding of a resin material with respect to the second stamper. At this time, the 2nd board | substrate 18 (refer FIG. 6) by which the surface was made into the flat surface is produced.

  Thereafter, in step S106 of FIG. 13, the first information recording layer 22 is formed on the surface of the first substrate 14, and then the semitransparent reflective layer 24 is formed on the first information recording layer 22, and further the semitransparent reflection is performed. An intermediate layer 20 is formed on the layer 24.

  Thereafter, in step S207 of FIG. 13, the third stamper is pressed against the intermediate layer 20 formed on the first substrate. At this time, the unevenness of the third stamper is transferred to the surface of the intermediate layer 20.

  Thereafter, in step S208 of FIG. 13, the barrier layer 30 is formed on the intermediate layer 20, the second information recording layer 28 is then formed on the barrier layer 30, and the reflective layer is further formed on the second information recording layer 28. 26 is formed. At this time, the reflective layer 26 is formed reflecting the unevenness of the intermediate layer 20, and the second pregroove 16 having the depth h2 set in step S8 of FIG. 4 is formed.

  Thereafter, in step S209 of FIG. 13, the adhesive layer 48 is formed on the reflective layer 26, and then the second substrate 18 is adhered on the adhesive layer 48, whereby the second optical disc 10B is completed.

  Thus, in the design method according to the first embodiment, the first information recording layer 22 is based on the first absorbance at the wavelength of the laser light 32 of the first dye used in the first information recording layer 22. Is set to a depth h1 of the first pregroove 12 so as to satisfy the target reflectance, and based on the second absorbance at the wavelength of the laser light 32 of the second dye used in the second information recording layer 28, Since the depth h2 of the second pregroove 16 is set so that the two information recording layers satisfy the target reflectance, characteristics variations such as reflectance vary for each first optical disk 10A or each second optical disk 10B. The first optical disc 10A and the second optical disc 10B can be manufactured in a small amount, and the yield of the first optical disc 10A and the second optical disc 10B can be improved and the development period can be shortened.

  The first optical disc 10A and the second optical disc 10B are suitable as DVD-R and DVD + R. In this case, in the DVD-R, the groove is wobbled at 100 to 200 KHz, and in the DVD + R, the groove is wobbled at 800 to 900 KHz.

  Next, a design method according to the second embodiment will be described with reference to FIG.

  In the design method according to the second embodiment, the first information recording layer 22 has a target recording sensitivity (hereinafter referred to as target) based on the first absorbance of the first dye used in the first information recording layer 22. The depth h1 of the first pregroove 12 is set so as to satisfy (recording sensitivity). Further, based on the second absorbance of the second dye used in the second information recording layer 28, the second pregroove depth h1 is set so that the second information recording layer 28 satisfies the target recording sensitivity. To do.

  Specifically, first, in step S301 of FIG. 14, the first absorbance of the first dye used in the first information recording layer 22 (the wavelength of the laser beam 32 used, for example, the absorbance at 650 nm) and the recording sensitivity. (The fourth correlation) is obtained. As shown in FIG. 15, the fourth correlation has a relationship in which the recording sensitivity decreases as the first absorbance increases.

  Thereafter, in step S302 of FIG. 14, a correlation (fifth correlation) between the depth of the first pregroove 12 and the recording sensitivity is obtained. As shown in FIG. 16, the fifth correlation has a relationship in which the recording sensitivity decreases as the depth of the first pregroove 12 increases.

  Thereafter, in step S303 in FIG. 14, the correlation between the first absorbance at the target recording sensitivity (for example, 40 mW) and the depth of the first pregroove 12 (sixth correlation) from the fourth correlation and the fifth correlation. Ask for. As shown in FIG. 17, the sixth correlation has a relationship in which the depth of the first pregroove 12 decreases as the first absorbance increases.

  In step S304 of FIG. 14, the depth h1 of the first pregroove 12 is set based on the first absorbance of the first dye used and the sixth correlation.

  On the other hand, the depth h2 of the second pregroove 16 is set by taking the following steps.

  That is, first, in step S305 in FIG. 14, the correlation between the second absorbance of the second dye used in the second information recording layer 28 (the wavelength of the laser beam 32 used, for example, the absorbance at 650 nm) and the recording sensitivity. (14th correlation) is obtained. As shown in FIG. 18, the fourteenth correlation has a relationship in which the recording sensitivity decreases as the second absorbance increases.

  Thereafter, in step S306 of FIG. 14, the correlation (fifteenth correlation) between the depth of the second pregroove 16 and the recording sensitivity is obtained. As shown in FIG. 19, the fifteenth correlation has a relationship in which the recording sensitivity decreases as the depth of the second pregroove 16 increases.

  Thereafter, in step S307 of FIG. 14, the correlation (the 16th correlation) between the second absorbance at the target recording sensitivity (for example, 40 mW) and the depth of the second pregroove is obtained from the 14th correlation and the 15th correlation. Ask. As shown in FIG. 20, the sixteenth correlation has a relationship in which the depth of the second pregroove 16 decreases as the second absorbance increases.

  In step S308 in FIG. 14, the depth h2 of the second pregroove 16 is set based on the second absorbance of the second dye used and the sixteenth correlation.

  As described above, after the depth h1 of the first pregroove 12 and the depth h2 of the second pregroove 16 are determined, as shown in FIG. 11 or FIG. 13, the first optical disk 10A or the second optical disk 10B is manufactured. Enter the process.

  Thus, in the design method according to the second embodiment, the first information recording layer 22 is based on the first absorbance at the wavelength of the laser light 32 of the first dye used in the first information recording layer 22. Is set to a depth h1 of the first pregroove 12 so as to satisfy the target recording sensitivity, and based on the second absorbance at the wavelength of the laser light 32 of the second dye used in the second information recording layer 28, 2 Since the depth h2 of the second pregroove 16 is set so that the information recording layer 28 satisfies the target recording sensitivity, characteristic variations such as recording sensitivity vary for each first optical disk 10A or each second optical disk 10B. The first optical disc 10A and the second optical disc 10B can be manufactured with a small amount, and the yield of the first optical disc 10A and the second optical disc 10B can be improved and the development period can be shortened. It can be.

  Next, a design method according to the third embodiment will be described with reference to FIGS.

  The design method according to the third embodiment is a combination of the design methods according to the first and second embodiments described above.

  Specifically, first, in step S401 of FIG. 21, the correlation between the first absorbance and the reflectance of the first dye used in the first information recording layer 22 (first correlation: see FIG. 5) is obtained. Ask.

  Thereafter, in step S402 in FIG. 21, a correlation between the depth of the first pregroove 12 and the reflectance (second correlation: see FIG. 6) is obtained.

  Thereafter, in step S403 of FIG. 21, the correlation between the first absorbance at the target reflectance (for example, 16%) and the depth of the first pregroove 12 (third correlation) from the first correlation and the second correlation. : See FIG. 7).

  Thereafter, in step S404 of FIG. 21, the first depth of the first pregroove 12 is obtained based on the first absorbance and the third correlation of the first dye used.

  Thereafter, in step S405 of FIG. 21, a correlation between the first absorbance and the recording sensitivity (fourth correlation: see FIG. 15) is obtained.

  Thereafter, in step S406 in FIG. 21, a correlation between the depth of the first pregroove 12 and the recording sensitivity (fifth correlation: see FIG. 16) is obtained.

  Thereafter, in step S407 of FIG. 21, the correlation between the first absorbance at the target recording sensitivity (for example, 40 mW) and the depth of the first pregroove 12 (sixth correlation: from the fourth correlation and the fifth correlation). 17).

  Thereafter, in step S408 of FIG. 21, the second depth of the first pregroove 12 is obtained based on the first absorbance of the first dye used and the sixth correlation.

  Then, in step S409 of FIG. 21, an intermediate value between the first depth obtained in step S404 and the second depth obtained in step S408 is set as the depth h1 of the first pregroove 12.

  On the other hand, the depth h2 of the second pregroove 16 is set by taking the following steps shown in FIG.

  That is, first, in step S501 of FIG. 22, the correlation between the second absorbance and the reflectance of the second dye used in the second information recording layer 28 (11th correlation: see FIG. 8) is obtained.

  Thereafter, in step S502 of FIG. 22, the correlation between the depth of the second pregroove 16 and the reflectance (the twelfth correlation: see FIG. 9) is obtained.

  Thereafter, in step S503 of FIG. 22, from the eleventh correlation and the twelfth correlation, the correlation between the second absorbance at the target reflectance (for example, 16%) and the depth h2 of the second pregroove 16 (the thirteenth Correlation: See FIG. 10).

  Thereafter, in step S504 of FIG. 22, the eleventh depth of the second pregroove 16 is obtained based on the second absorbance and the thirteenth correlation of the second dye used.

  Thereafter, in step S505 in FIG. 22, a correlation between the second absorbance and the recording sensitivity (fourteenth correlation: see FIG. 18) is obtained.

  Thereafter, in step S506 in FIG. 22, a correlation between the depth of the second pregroove 16 and the recording sensitivity (fifteenth correlation: see FIG. 19) is obtained.

  Thereafter, in step S507 in FIG. 22, the correlation between the second absorbance at the target recording sensitivity (for example, 40 mW) and the depth of the second pregroove 16 (the sixteenth correlation: (See FIG. 20).

  Thereafter, in step S508 of FIG. 22, the twelfth depth of the second pregroove 16 is obtained based on the second absorbance of the second dye used and the sixteenth correlation.

  Then, in step S509 in FIG. 22, an intermediate value between the eleventh depth obtained in step S504 and the twelfth depth obtained in step S508 is set as the depth h2 of the second pregroove 16.

  As described above, after the depth h1 of the first pregroove 12 and the depth h2 of the second pregroove 16 are determined, as shown in FIG. 11 or FIG. 13, the first optical disk 10A or the second optical disk 10B is manufactured. Enter the process.

  Thus, in the design method according to the third embodiment, the first information recording layer 22 is based on the first absorbance at the wavelength of the laser light 32 of the first dye used in the first information recording layer 22. Is set to a depth h1 of the first pregroove 12 so that the target reflectance and the target recording sensitivity are satisfied, and the second absorbance at the wavelength of the laser light 32 of the second dye used in the second information recording layer 28 is set. Therefore, the depth h2 of the second pre-groove 16 is set so that the second information recording layer 28 satisfies the target reflectance and the target recording sensitivity. For each 10B, the first optical disc 10A and the second optical disc 10B with little variation in characteristics such as reflectance and recording sensitivity can be manufactured, and the yield of the first optical disc 10A and the second optical disc 10B can be manufactured. Rino improved and it is possible to shorten the development period.

  Next, the material of each layer constituting the first optical disc 10A and the second optical disc 10B will be described.

  First, as the first substrate 14 and the second substrate 18, various materials used as substrate materials for conventional optical discs can be arbitrarily selected and used.

  Specifically, glass; acrylic resin such as polycarbonate and polymethyl methacrylate; vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin; amorphous polyolefin; polyester; metal such as aluminum; These may be used together if desired.

  Among the above materials, thermoplastic resins such as amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable from the viewpoints of moisture resistance, dimensional stability, and low price.

  When these resins are used, the first substrate 14 and the second substrate 18 can be manufactured by injection molding.

  Moreover, the thickness of the 1st board | substrate 14 and the 2nd board | substrate 18 is the range of 0.7-2 mm, It is preferable that it is the range of 0.9-1.6 mm, and is 1.0-1.3 mm. It is more preferable.

  The upper limit of the track pitch of the first pregroove 12 formed on the first substrate 14 and the second pregroove 16 formed on the second substrate 18 is 800 nm or less, preferably 500 nm or less, It is more preferably 420 nm or less, further preferably 370 nm or less, and particularly preferably 330 nm or less. Further, the lower limit is preferably 50 nm or more, more preferably 100 nm or more, further preferably 200 nm or more, and particularly preferably 260 nm or more.

  The upper limit of the widths (half widths) of the first pregroove 12 and the second pregroove 16 is 500 or less, preferably 250 nm or less, more preferably 200 nm or less, and 170 nm or less. More preferably, it is particularly preferably 150 nm or less. Further, the lower limit is preferably 23 nm or more, more preferably 50 nm or more, further preferably 80 nm or more, and particularly preferably 100 nm or more.

  The (groove) depth of the first pregroove 12 and the second pregroove 16 is preferably 150 nm or less, more preferably 100 nm or less, even more preferably 70 nm or less, and even more preferably 50 nm or less. It is particularly preferred that Further, the lower limit is preferably 5 nm or more, more preferably 10 nm or more, further preferably 20 nm or more, and particularly preferably 28 nm or more.

  The upper limit of the angles of the first pregroove 12 and the second pregroove 16 is preferably 80 ° or less, more preferably 70 ° or less, further preferably 60 ° or less, and 50 ° or less. It is particularly preferred that Further, the lower limit value is preferably 20 ° or more, more preferably 30 ° or more, and further preferably 40 ° or more.

  The upper limit value and the lower limit value related to the first pregroove 12 and the second pregroove 16 can be arbitrarily combined.

  The values of the first pregroove 12 and the second pregroove 16 can be measured by an AFM (atomic force microscope).

  For example, the angle of the first pregroove 12 refers to the surface of the first substrate 14 before the groove is formed, with a depth of D / 10 from the surface when the groove depth of the first pregroove 12 is D. This is an angle formed by a straight line connecting the sloped portion and the sloped portion having a height of D / 10 from the deepest portion of the groove and the surface of the first substrate 14 (bottom surface of the groove portion). The same applies to the angle of the second pregroove 16.

  Of course, the current DVD-R specifications are also preferably adopted. That is, the track pitch = 740 nm, the width of the first pregroove 12 = 350 nm, the depth = 130 nm, the angle = about 60 °, the width of the second pregroove 16 = 420 nm, the depth = 35 nm, and the angle = about 60 °. It is also preferably adopted.

  When the first optical disc 10A and the second optical disc 10B are read-only optical discs, pits indicating predetermined information are formed at the same time as the first pre-groove 12 and the second pre-groove 16 are formed. The

  In addition, it is preferable to form an undercoat layer on the surfaces of the first substrate 14 and the second substrate 18 for the purpose of improving the flatness and the adhesive force.

  Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, and chloro. Polymer materials such as sulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc .; silane coupling Surface modifiers such as agents;

  The undercoat layer is formed by dissolving or dispersing the above materials in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, and preferably in the range of 0.01 to 10 μm.

  The first information recording layer 22 and the second information recording layer 28 are preferably of a dye type containing a dye as a recording material. Examples of the recording material contained in the first information recording layer 22 and the second information recording layer 28 include organic compounds such as dyes and phase change metal compounds.

  Among these, the dye-type first information recording layer 22 and the second information recording layer 28 that can record information only once with a laser beam are preferable. The dye-type first information recording layer 22 and the second information recording layer 28 preferably contain a dye having absorption in the recording wavelength region. Examples of the dye include a cyanine dye, an oxonol dye, a metal complex dye, an azo dye, and a phthalocyanine dye, and among them, an oxonol dye is preferable. By containing an oxonol dye, stable recording / reproducing characteristics can be maintained over a long period of time.

  Here, the oxonol dye used in the first information recording layer 22 and the second information recording layer 28 will be described.

  Specific examples of the oxonol dye include F.I. M.M. Examples include those described by Harmer, Heterocyclic Compounds-Cyanine Dies and Related Compounds, John & Wiley & Sons, New York, London, 1964.

  The oxonol dye can be synthesized by a condensation reaction between a corresponding active methylene compound and a methine source (a compound used for introducing a methine group into a methine dye).

  Details of this type of compound are described in JP-B-39-22069, JP-A-43-3504, JP-A-52-38056, JP-A-54-38129, JP-A-55-10059, and JP-A-58-35544. No. 49-99620, No. 52-92716, No. 59-16834, No. 63-316853, No. 64-40827, and British Patent No. 1133986, U.S. Pat. Nos. 3,247,127, 4042397, 4,181,225, 5,213,956 and 5,260,179 can be referred to. Also described in JP-A-63-209995, JP-A-10-309871 and JP-A-2002-249674.

  Oxonol dyes may be used alone or in combination of two or more. Further, the above-mentioned oxonol dye and other dye compounds may be used in combination. Examples of the dye to be used in combination include azo dyes (including those complexed with metal ions), pyromethene dyes, cyanine dyes, and the like.

  The dye preferably has a thermal decomposition temperature in the range of 100 ° C to 350 ° C. Furthermore, what is in the range of 150 to 300 degreeC is preferable. Furthermore, the thing in the range of 200 to 300 degreeC is preferable.

  Complex refractive index due to the optical characteristics of the amorphous film of the dye used in the first information recording layer 22 and the second information recording layer 28 ("Oxonol dye described above" or "Oxonol dye described above and dye used in combination with this") The coefficients n (real part: refractive index) and k (imaginary part: extinction coefficient) are preferably 2.0 ≦ n ≦ 3.0 and 0.005 ≦ k ≦ 0.30. More preferably, 2.1 ≦ n ≦ 2.7 and 0.01 ≦ k ≦ 0.15. Most preferably, 2.15 ≦ n ≦ 2.50 and 0.03 ≦ k ≦ 0.10.

  The first information recording layer 22 and the second information recording layer 28 can contain various anti-fading agents for further improving light resistance. Representative examples of the anti-fading agent include metal complexes, diimmonium salts, aminium salts represented by general formula (III), (IV) or (V) described in JP-A-3-224793, and JP-A-2-300287. And nitroso compounds disclosed in JP-A-2-300288 and TCNQ derivatives disclosed in JP-A-10-151861.

  The first information recording layer 22 and the second information recording layer 28 are formed by preparing a coating solution by dissolving the oxonol dye described above and, if desired, a quencher, a binder and the like in a solvent. It can be carried out by drying after coating the surface of the substrate 14 and the surface of the second substrate 18 to form a coating film. 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 cyclohexane; ethers such as tetrahydrofuran, ethyl ether, dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; 2,2,3,3-tetrafluoro Fluorine solvents such as propanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, etc. That.

  The said solvent can be used individually or in combination of 2 or more types in consideration of the solubility of the compound to be 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.

  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; polyvinyl chloride, polyvinylidene chloride, Vinyl resins such as polyvinyl chloride / polyvinyl acetate copolymers; acrylic resins such as polymethyl acrylate and polymethyl methacrylate; polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, phenol / formaldehyde resins And synthetic organic polymers such as an initial condensate of a thermosetting resin.

  When a binder is used as the material for the first information recording layer 22 and the second information recording layer 28, the amount of the binder used is generally 0.01 relative to the amount of the dye including the oxonol dye described above. It exists in the range of -50 times amount (mass ratio), Preferably it exists in the range of 0.1-5 times amount (mass ratio). The pigment concentration of the coating solution thus prepared is generally in the range of 0.01 to 10% by mass, preferably in the range of 0.1 to 5% by mass.

  Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. Each of the first information recording layer 22 and the second information recording layer 28 may be a single layer or a multilayer. The thicknesses of the first information recording layer 22 and the second information recording layer 28 are generally in the range of 20 to 500 nm, preferably in the range of 50 to 300 nm.

  Next, the translucent reflective layer 24 and the reflective layer 26 will be described. The light reflective material that is a material of the reflective layer 26 is a material having a high reflectance with respect to laser light. Examples thereof include Mg, Se, and Y. Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al , Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, and other metals and metalloids, and stainless steel.

  Among these, preferred are Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel, and particularly preferred is Ag. These substances may be used alone or in combination of two or more or as an alloy. The reflective layer 26 can be formed on the first information recording layer 22, the second information recording layer 28, and the second substrate 18, for example, by vapor deposition, sputtering, or ion plating of the reflective material.

  And it is preferable that the layer thickness of the translucent reflective layer 24 exists in the range of 2-150 nm. The thickness of the reflective layer 26 is generally in the range of 10 to 300 nm, preferably in the range of 50 to 200 nm.

  Next, the barrier layer 30 is provided for the purpose of physically and chemically protecting the second information recording layer 28 and the like. The barrier layer 30 is provided in the first substrate 14 and the second substrate 18 in a portion where the first information recording layer 22 and the second information recording layer 28 are not provided for the purpose of improving scratch resistance and moisture resistance. May be.

Examples of the material used for the barrier layer 30 include inorganic substances such as SiO, SiO ₂ , MgF ₂ , SnO ₂ , Si ₃ N ₄ , and ZnO—Ga ₂ O ₃ ; thermoplastic resins, thermosetting resins, and UV curing. Organic substances such as a conductive resin;

  The barrier layer 30 can be provided by a method such as vacuum deposition, sputtering, or coating. Moreover, when using a thermoplastic resin and a thermosetting resin, it can also form by preparing the coating liquid which melt | dissolved these in the appropriate solvent, apply | coating this coating liquid, and drying. In the case of a UV curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, and then applying the coating solution and curing it by irradiation with UV light. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose. The layer thickness of the barrier layer 30 is generally in the range of 1 nm to 10 μm.

  Next, as described above, the intermediate layer 20 is provided at least between the first information recording layer 22 and the second information recording layer 28.

Examples of the material for the intermediate layer 20 and the adhesive layer 48 include thermoplastic resins, thermosetting resins, electron beam curable resins, ultraviolet curable resins, pressure-sensitive double-sided tapes, and inorganic materials such as SiO ₂ . These materials may be used alone or in combination, and may be used not only as a single layer but also as a multilayer film. Such an intermediate layer 20 can be formed by spin coating, casting, or sputtering. The thickness of the intermediate layer 20 is preferably 5 to 100 μm, more preferably 10 to 70 μm.

  The optical information recording medium design method, the optical information recording medium substrate and the optical information recording medium according to the present invention are not limited to the above-described embodiments, and various configurations are possible without departing from the gist of the present invention. Of course, it can be taken.

It is sectional drawing which abbreviate | omits and shows the 1st optical disk produced with the design method which concerns on the 1st-3rd embodiment. It is sectional drawing which shows a 1st board | substrate. It is sectional drawing which shows a 2nd board | substrate. It is a flowchart which shows the design method which concerns on 1st Embodiment. It is a characteristic view which shows the 1st correlation of the 1st light absorbency and reflectance of the 1st pigment | dye used for a 1st information recording layer. It is a characteristic view which shows the 2nd correlation of the depth of a 1st pregroove, and a reflectance. It is a characteristic view which shows the 3rd correlation with the 1st light absorbency in the target reflectance, and the depth of the 1st pregroove. It is a characteristic view which shows the 11th correlation between the 2nd light absorbency and reflectance of the 2nd pigment | dye used for a 2nd information recording layer. It is a characteristic view which shows the 12th correlation between the depth of a 2nd pregroove, and a reflectance. It is a characteristic view which shows the 13th correlation between the 2nd light absorbency in the target reflectance, and the depth of the 2nd pregroove. It is process drawing which shows the manufacturing method of a 1st optical disk. It is sectional drawing which abbreviate | omits and shows a 2nd optical disk partially. It is process drawing which shows the manufacturing method of a 2nd optical disk. It is a flowchart which shows the design method which concerns on 2nd Embodiment. It is a characteristic view which shows the 4th correlation of the 1st light absorbency and recording sensitivity of the 1st pigment | dye used for a 1st information recording layer. FIG. 10 is a characteristic diagram showing a fifth correlation between the depth of the first pregroove and the recording sensitivity. It is a characteristic view which shows the 6th correlation with the 1st light absorbency in the target recording sensitivity, and the depth of the 1st pregroove. It is a characteristic view which shows the 14th correlation of the 2nd light absorbency and recording sensitivity of the 2nd pigment | dye used for a 2nd information recording layer. It is a characteristic view showing a 15th correlation between the depth of the second pregroove and the recording sensitivity. It is a characteristic figure showing the 16th correlation of the 2nd light absorbency and the depth of the 2nd pregroove in target recording sensitivity. It is a flowchart (the 1) which shows the design method which concerns on 3rd Embodiment. It is a flowchart (the 2) which shows the design method which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10A, 10B ... Optical disk 12 ... 1st pre-groove 14 ... 1st board | substrate 16 ... 2nd pre-groove 18 ... 2nd board | substrate 20 ... Intermediate | middle layer 22 ... 1st information recording layer 28 ... 2nd information recording layer

Claims (9)

A method for designing an optical information recording medium having a substrate having a groove and a dye recording layer formed on the substrate, and recording and / or reproducing information by irradiating the dye recording layer with laser light In
The groove depth is set so as to satisfy at least the target reflectance of the optical information recording medium based on the absorbance of the dye used in the dye recording layer at the wavelength of the laser beam. Method for designing optical information recording medium. The method for designing an optical information recording medium according to claim 1,
From the first correlation between the absorbance and the reflectance and the second correlation between the groove depth and the reflectance, a third correlation between the absorbance and the groove depth at the target reflectance is obtained. ,
A method for designing an optical information recording medium, wherein the depth of the groove is set based on the third correlation. A method for designing an optical information recording medium having a substrate having a groove and a dye recording layer formed on the substrate, and recording and / or reproducing information by irradiating the dye recording layer with laser light In
The groove depth is set so as to satisfy at least the target recording sensitivity of the optical information recording medium based on the absorbance of the dye used in the dye recording layer at the wavelength of the laser beam. Method for designing optical information recording medium. The method for designing an optical information recording medium according to claim 3,
From the first correlation between the absorbance and the recording sensitivity and the second correlation between the groove depth and the recording sensitivity, a third correlation between the absorbance and the groove depth at the target recording sensitivity is obtained. ,
A method for designing an optical information recording medium, wherein the depth of the groove is set based on the third correlation. A method for designing an optical information recording medium having a substrate having a groove and a dye recording layer formed on the substrate, and recording and / or reproducing information by irradiating the dye recording layer with laser light In
Based on the absorbance of the dye used in the dye recording layer at the wavelength of the laser light, the depth of the groove is set so as to satisfy the target reflectance and target recording sensitivity of the optical information recording medium. A method for designing an optical information recording medium. The method of designing an optical information recording medium according to claim 5,
From the first correlation between the absorbance and the reflectance and the second correlation between the groove depth and the reflectance, a third correlation between the absorbance and the groove depth at the target reflectance is obtained. ,
A sixth correlation between the absorbance and the groove depth at the target recording sensitivity is obtained from the fourth correlation between the absorbance and the recording sensitivity and the fifth correlation between the groove depth and the recording sensitivity. ,
Based on the third correlation, a first depth of the groove is set,
Based on the sixth correlation, a second depth of the groove is set,
A method for designing an optical information recording medium, wherein an intermediate value between the first depth and the second depth is set as the depth of the groove. The method for designing an optical information recording medium according to any one of claims 1 to 6,
The optical information recording medium has a substrate on which the groove is formed, and the recording layer and the groove are arranged in this order when viewed from a direction in which the laser beam is irradiated. A recording medium design method.   A substrate for an optical information recording medium designed by using the method for designing an optical information recording medium according to claim 1. An optical information recording medium designed using the method for designing an optical information recording medium according to claim 1.

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