JP2007280575A - Manufacturing method of optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily conform parameters of a jitter value, a degree of modulation, a reflectance value and the like concerning access by a laser light to an optical disk to respective corresponding specification values. <P>SOLUTION: In a manufacturing method of an optical information recording medium, one or more first prepits 42A used for adjusting at least output of laser light for recording and/or reproduction of a first information recording layer 14 are formed in a system lead-in area 24A disposed in an innermost peripheral part of a first substrate and the first information recording layer 14 is formed on the first substrate. Only the parts corresponding to the first prepits 42A in the first information recording layer 14 are locally irradiated with laser light having a fixed output level (refer to an irradiation region 44 with laser light) to change an optical constant of the parts irradiated with the laser light in the first information recording layer 14 (refer to a region 48 whose optical constant is changed). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  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 disk having two information recording layers is formed on a substrate having a first pregroove formed on the surface, a thin reflective layer formed along the irregularities of the surface of the substrate, and the thin reflective layer First information recording layer formed, an intermediate layer formed on the surface of the first information recording layer and having irregularities formed thereon, and a second information recording layer formed along the irregularities on the surface of the intermediate layer A 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.

  Conventionally, when recording information by irradiating the information recording layer with laser light, the intensity of the laser light is optimized, or the recording / reproducing apparatus incorporates a system for changing the recording strategy for each optical disc of a different manufacturer. Such a technique has been proposed (for example, Patent Document 4). This is due to the fact that the optical information recording medium cannot be recorded the same even under the same recording conditions due to the recording device, recording material, environmental temperature, wavelength variation of the laser light source, and the like.

Japanese Patent Laid-Open No. 2005-4808 Japanese Patent Laid-Open No. 10-283682 JP-A-8-203125 Japanese Unexamined Patent Publication No. Hei 8-249626

  Incidentally, regarding the access to the optical information recording medium by the laser beam, standard values are determined for jitter, modulation degree, reflectance, etc., and it is necessary to perform access so as to conform to each standard value.

  Therefore, by arranging at least a region for adjusting the output of the laser beam in the innermost part of the optical information recording medium and reproducing one or more pits formed in the region, jitter, modulation degree, It is considered to adjust the output of the laser beam, the reproduction gain, and the like so that the reflectance and the like match each standard value. Therefore, it is important that the pits in the area can be reliably reproduced.

  However, when the second optical disk having the two information recording layers described above is assumed, since the area is arranged on the innermost periphery of the second optical disk, there is a limitation that the pit width cannot be increased unnecessarily. is there. Further, as shown in FIG. 15, as can be seen from the relationship between the thickness of the reflective layer and the amount of jitter included in the reproduction signal, the reproduction light reflected by the thin reflection layer formed on the second optical disc has a higher harmonic. A large number of aliasing components of the signal due to waves are included, and accordingly, the reproduced signal includes a lot of jitter. Therefore, how to reliably reproduce pits in an environment where the amount of jitter increases is a problem.

  The present invention has been made in consideration of such a problem, and is recorded in an area in which at least one pit for adjusting the output of laser light is formed at the innermost part of the substrate. In addition, the reproduction signal of the pit in the area can be taken out with high accuracy and certainty by irradiation with the laser beam for reproduction, and the jitter, modulation degree, reflection regarding the access to the optical information recording medium by the laser beam. It is an object of the present invention to provide a method for manufacturing an optical information recording medium in which parameters such as rate can be easily adapted to corresponding standard values.

  According to a first aspect of the present invention, there is provided a method of manufacturing an optical information recording medium comprising a substrate and a recording layer formed on the substrate, and recording information by irradiating the recording layer with laser light. In the method of manufacturing an optical information recording medium for performing reproduction, pits for forming at least one pit used for adjusting at least the output of the laser beam to the recording layer in the innermost part of the substrate A forming step; a recording layer forming step for forming the recording layer on the substrate; and a laser light irradiation step for irradiating a laser beam to the innermost peripheral portion of the recording layer where the pits are formed; It is characterized by having.

  According to a second aspect of the present invention, there is provided an optical information recording medium manufacturing method comprising a substrate and a recording layer formed on the substrate, and irradiating the recording layer with laser light to record information. In the method of manufacturing an optical information recording medium for recording and / or reproducing, at least one pit used for adjusting at least the output of the laser beam to the recording layer is formed in the innermost part of the substrate A pit forming step, a recording layer forming step for forming the recording layer on the substrate, and an optical constant changing step for changing an optical constant of the recording layer corresponding to the pit among the recording layers. Features.

  In the first and second aspects of the present invention, irradiation of the recording and / or reproducing laser light to the pits formed on the innermost peripheral portion of the substrate with high accuracy and certainty. An optical information recording medium that can take out a reproduction signal of a pit and can easily adapt parameters such as jitter, modulation degree, and reflectance relating to access to the optical information recording medium by laser light to corresponding standard values. Can be manufactured.

  In the first aspect of the present invention, the laser beam irradiation step is performed for the purpose of changing an optical constant of the recording layer in the innermost peripheral portion of the recording layer where the pits are formed. You may make it irradiate a laser beam with respect to the said recording layer of an inner peripheral part.

  In this case, while rotating the substrate relatively, the innermost peripheral portion is continuously irradiated with the laser beam having a constant output level as time elapses. The optical constant may be changed.

  In the second aspect of the present invention, the optical constant changing step may change the optical constant of the recording layer filled in the pit.

  In the second aspect of the present invention, in the optical constant changing step, laser light is emitted for the purpose of changing the optical constant of the recording layer with respect to the innermost peripheral portion of the substrate where the pits are formed. You may make it irradiate.

  In this case, the optical constant of the recording layer is changed by continuously irradiating the innermost peripheral portion with the laser beam having a constant output level as time passes while relatively rotating the substrate. It may be.

  In the first and second aspects of the present invention described above, the output level of the laser light applied to the innermost peripheral portion is 3 mW or more and 10 mW or less when the recording linear velocity is 1 × (for example, 6.61 m / sec). Preferably, it is 4 mW or more and 6 mW or less. When the recording linear velocity is increased and the output level of the laser beam is further increased (for example, 10 mW at a double speed), the tact time can be improved.

  In the recording layer forming step, a dye to be the recording layer may be applied on the substrate.

  The optical information recording medium manufactured in the first and second aspects of the present invention includes an objective lens for condensing the laser light on the recording layer with a wavelength of the recording and / or reproducing laser light of 405 nm. May have a numerical aperture of 0.65 and a distance from the end face of the optical information recording medium to the recording layer of 0.6 mm.

  Next, a method for manufacturing an optical information recording medium according to a third aspect of the present invention includes a first substrate, a second substrate, a first recording layer formed on the first substrate, and formed on the second substrate. The first recording layer and the second recording layer are arranged in this order when viewed from the direction of irradiation with the recording and / or reproducing laser light, and at least the first recording layer is provided. In a method for manufacturing an optical information recording medium in which information is recorded and / or reproduced by irradiating a recording layer with laser light, the laser for the first recording layer is formed on the innermost part of the first substrate. A first pit forming step for forming one or more first pits used to adjust at least the output of light; a first recording layer forming step for forming the first recording layer on the first substrate; In the innermost part of the second substrate, on the second recording layer A second pit forming step for forming one or more second pits used for adjusting at least the output of the laser beam, and a second recording layer formation for forming the second recording layer on the second substrate Of the first recording layer, the step of laminating the second substrate on the first substrate so that the first recording layer and the second recording layer face each other, and the first recording layer A first laser beam irradiation step of irradiating the innermost peripheral portion where the pits are formed with a laser beam; and the innermost peripheral portion where the second pits are formed in the second recording layer. And a second laser beam irradiation step for irradiating the laser beam.

  According to a fourth aspect of the present invention, there is provided an optical information recording medium manufacturing method, comprising: a first substrate; a second substrate; a first recording layer formed on the first substrate; and the second substrate. The first recording layer and the second recording layer are arranged in this order when viewed from the direction of irradiation with the recording and / or reproducing laser beam, and at least the first recording layer is provided. In a method for manufacturing an optical information recording medium in which information is recorded and / or reproduced by irradiating a layer with laser light, the laser light for the first recording layer is formed on the innermost periphery of the first substrate. A first pit forming step for forming one or more first pits used to adjust at least the output of the first recording layer, a first recording layer forming step for forming the first recording layer on the first substrate, In the innermost part of the second substrate, the second recording layer A second pit forming step for forming one or more second pits used for adjusting at least the output of the laser beam, and a second recording layer formation for forming the second recording layer on the second substrate Of the first recording layer, the step of laminating the second substrate on the first substrate so that the first recording layer and the second recording layer face each other, and the first recording layer A first optical constant changing step for changing the optical constant of the recording layer corresponding to the pit; and a second optical constant changing step for changing the optical constant of the recording layer corresponding to the second pit of the second recording layer; It is characterized by having.

  In the third and fourth aspects of the present invention, recording and / or recording on the first pit formed in the innermost peripheral portion of the first substrate and the second pit formed in the innermost peripheral portion of the second substrate. By reproducing the laser beam for reproduction, the reproduction signal of the first pit and the second pit in the area can be taken out with high accuracy and reliability, and jitter and modulation related to the access to the optical information recording medium by the laser beam. It is possible to manufacture an optical information recording medium in which parameters such as degree and reflectance can be easily adapted to the corresponding standard values.

  In the third aspect of the present invention, in the first laser light irradiation step, an optical constant of the first recording layer in the innermost peripheral portion of the first recording layer where the first pit is formed is changed. For the purpose of irradiating, the laser beam is irradiated to the first recording layer in the innermost peripheral portion, and the second laser beam irradiation step includes forming the second pit in the second recording layer. For the purpose of changing the optical constant of the second recording layer in the innermost peripheral portion, the second recording layer in the innermost peripheral portion may be irradiated with laser light.

  In this case, in the first laser beam irradiation step, the laser beam having a constant output level with the passage of time is applied to the innermost circumference of the first substrate while relatively rotating the optical information recording medium. The optical constant of the first recording layer in the innermost peripheral portion is changed by continuing to irradiate the portion, and the second laser light irradiation step is performed with the passage of time while relatively rotating the optical information recording medium. Accordingly, the optical constant of the second recording layer in the innermost peripheral portion may be changed by continuously irradiating the innermost peripheral portion of the second substrate with the laser beam having a constant output level.

  In the fourth aspect of the present invention, the first optical constant changing step changes an optical constant of the first recording layer filled in the first pit, and the second optical constant changing step includes the second optical constant changing step. The optical constant of the second recording layer filled in the pits may be changed.

  In the fourth aspect of the present invention, in the first optical constant changing step, the optical constant of the recording layer is changed with respect to the innermost peripheral portion of the first substrate where the first pit is formed. In the second optical constant changing step, the optical constant of the recording layer is changed with respect to the innermost peripheral portion of the second substrate on which the second pit is formed. For this purpose, laser light may be irradiated.

  In this case, in the first optical constant changing step, the laser light having a constant output level as time elapses while rotating the optical information recording medium relatively. The optical constant of the first recording layer corresponding to the first pit is changed by continuously irradiating the portion, and the second optical constant changing step is performed as time elapses while relatively rotating the optical information recording medium. Accordingly, the optical constant of the second recording layer corresponding to the second pit may be changed by continuously irradiating the innermost peripheral portion of the second substrate with the laser beam having a fixed output level.

  In the third and fourth aspects of the present invention described above, the output level of the laser light applied to the innermost peripheral portions of the first recording layer and the second recording layer is a recording linear velocity of 1 × (for example, 6.61 m). / Sec), it is preferably 3 mW or more and 10 mW or less, more preferably 4 mW or more and 6 mW or less. When the recording linear velocity is increased and the output level of the laser beam is further increased (for example, 10 mW at a double speed), the tact time can be improved.

  In the first recording layer forming step, a dye to be the first recording layer is applied on the first substrate, and in the second recording layer forming step, the second recording layer and the second recording layer are formed on the second substrate. You may make it apply | coat the pigment | dye which becomes.

  The optical information recording medium manufactured in the third and fourth aspects of the present invention may be configured such that the wavelength of the recording and / or reproducing laser beam is 405 nm, and the laser beam is focused on at least the first recording layer. The numerical aperture of the objective lens may be 0.65, and the distance from the end face of the optical information recording medium to the first recording layer may be 0.6 mm.

  As described above, according to the method for manufacturing an optical information recording medium according to the present invention, at least one pit for adjusting the output of the laser beam is formed at the innermost part of the substrate. By irradiating the area with the recording and / or reproducing laser beam, the reproduction signal of the pit in the area can be taken out with high accuracy and reliability, and the jitter related to the access to the optical information recording medium by the laser beam, Parameters such as modulation degree and reflectance can be easily adapted to the corresponding standard values.

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

  As shown in FIG. 1, the optical disc 10 according to the present embodiment includes a first substrate 12, a first information recording layer 14 formed on the first substrate 12, a second substrate 16, and a second substrate. The second information recording layer 18 formed on the substrate 16 is provided, and the first substrate 12 and the second substrate 16 are bonded to each other through the intermediate layer 20.

  The optical disc 10 has an information recording area 22 where user information is recorded and an area 24 used to adjust at least the output of the laser beam. In particular, a portion corresponding to the region 24 in the first information recording layer 14 is a system lead-in region 24A, and a portion corresponding to the region 24 in the second information recording layer 18 is a system lead-out region 24B. Has been.

  Specifically, as shown in FIG. 2, in the information recording area 22 of the optical disc 10, the first pregroove 26 is formed on the surface of the first substrate 12, and the second pregroove 28 is also formed on the surface of the second substrate 16. Is formed.

  As shown in FIG. 3, the first information recording layer 14 is formed on the surface of the first substrate 12 along the unevenness of the first pregroove 26, and the first information recording layer 14 having a small thickness is formed on the first information recording layer 14. A reflective layer 30 is formed.

  As shown in FIG. 4, the second reflective layer 32 is formed on the surface of the second substrate 16 along the irregularities of the second pregroove 28, and the second information recording layer 18 is formed on the second reflective layer 32. The barrier layer 34 is formed on the second information recording layer 18.

  Then, when the first substrate 12 and the second substrate 16 are bonded together, the first information recording layer 14 formed on the first substrate 12 and the first substrate 16 formed on the second substrate 16 as shown in FIG. The optical disk 10 is configured by making the two information recording layers 18 face each other and further bonding them with an intermediate layer 20 interposed between the first substrate 12 and the second substrate 16.

  When recording information on the first information recording layer 14, a laser beam 36 for recording and / or reproduction is irradiated in a direction from the end face 12 a of the first substrate 12 toward the first information recording layer 14, and the laser beam is emitted. 36 (36) is imaged on the first information recording layer 14 to record information (pits). At this time, information is recorded in a portion of the first information recording layer 14 corresponding to the groove 38 of the first pre-groove 26. As the recording laser beam 36, 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.

  In particular, when the wavelength of the laser beam 36 is 405 nm, the numerical aperture of an objective lens (not shown) that focuses the laser beam 36 on the first information recording layer 14 is 0.65, and the surface 12a of the first substrate 12 It is preferable that the distance from the (end face) to the first information recording layer 14 corresponds to 0.6 mm.

  Of course, when the wavelength of the laser beam 36 is 405 nm, the numerical aperture of an objective lens (not shown) that focuses the laser beam 36 on the first information recording layer 14 is 0.85, and the surface 12a of the first substrate 12 The distance from the (end face) to the first information recording layer 14 may correspond to 0.1 mm.

  When information is recorded on the second information recording layer 18, the recording laser beam 36 is irradiated in the direction from the end face 12 a of the first substrate 12 toward the second information recording layer 18, and the laser beam 36 is emitted from the second information recording layer 18. Information (pits) is recorded by forming an image on the information recording layer 18. At this time, information is recorded in a portion of the second information recording layer 18 corresponding to the land 40 of the second pregroove 28.

  Therefore, the information recorded on the first information recording layer 14 and the information recorded on the second information recording layer 18 are provided by interposing the intermediate layer 20 between the first information recording layer 14 and the second information recording layer 18. Information interference can be prevented, and a good recording / reproducing signal can be obtained by the first information recording layer 14 and the second information recording layer 18.

  On the other hand, as shown in FIGS. 5 and 6, one or more first prepits 42A are formed in the system lead-in area 24A of the optical disc 10, and also in the system lead-out area 24B as shown in FIGS. As shown, one or more second prepits 42B are formed.

  The first prepit 42A formed in the system lead-in area 24A is for adjusting at least the output of the laser beam 36 to the first information recording layer 14, and the second prepit 42A formed in the system lead-out area 24B. The prepit 42B is for adjusting at least the output of the laser beam 36 to the second information recording layer 18.

  That is, at the start of access to the first information recording layer 14 by the laser light 36, the first pre-pit 42A in the system lead-in area 24A is reproduced, and the jitter, modulation degree, reflectance, etc. are based on the reproduction information. The output of the laser beam 36, the reproduction gain, etc. are adjusted so as to conform to each standard value. Similarly, the second pre-pit 42B in the system lead-out area 24B is reproduced at the start of access to the second information recording layer 18 by the laser light 36, and jitter, modulation degree, reflectance, etc. are reproduced based on the reproduction information. Adjusts the output of the laser light 36, the reproduction gain, and the like so as to conform to each standard value.

  However, since the system lead-in area 24A and the system lead-out area 24B are arranged on the innermost circumference of the optical disc 10, as shown in FIGS. 6 and 7, the half width W1 and the second pre-pit of the first pre-pit 42A There is a limitation that the half width W2 of 42B cannot be increased unnecessarily. Here, the half width W1 of the first prepit 42A indicates a width at a half point of the depth h1 of the first prepit 42A, and the half width W2 of the second prepit 42B is the depth of the second prepit 42B. The width at a point 1/2 of h2 is shown.

  Further, as shown in FIG. 15, as can be seen from the relationship between the thickness of the reflective layer and the amount of jitter included in the reproduction signal, the thin first reflective layer 30 formed on the first information recording layer 14 is formed. The reproduced light reflected in this manner contains a lot of signal folding components due to harmonics, and accordingly, the reproduced signal contains a lot of jitter. Therefore, even if the first prepit 42A in the system lead-in area 24A is irradiated with the laser light 36, there are many jitter components included in the reproduction signal, so various parameters are set based on the reproduction information of the first prepit 42A. The problem of not being able to do arises.

  Therefore, in forming the first prepit 42A, it is considered that the system lead-in area 24A is disposed on the innermost circumference of the optical disc 10, and further, the influence of jitter due to the thickness of the first reflective layer 30 is suppressed. In addition, it is preferable to determine the depth h1 and the half width W1 of the first prepit 42A. In this embodiment, the depth h1 of the first prepit 42A is 80 nm or more and 110 nm or less, and the half width W1 of the first prepit 42A is 160 nm or more and 190 nm or less.

  Similarly, in forming the second pre-pit 42B, it is considered that the system lead-out area 24B is disposed on the innermost circumference of the optical disc 10, and further, the influence of jitter due to the thickness of the second reflective layer 32 is suppressed. As described above, it is preferable to determine the depth h2 and the half width W2 of the second prepit 42B. In this embodiment, the depth h2 of the second prepit 42B is 25 nm or more and 35 nm or less, and the half width W2 of the second prepit 42B is 170 nm or more and 210 nm or less.

  The depth h1 and half width W1 of the first prepit 42A and the depth h2 and half width W2 of the second prepit 42B can be measured by an AFM (atomic force microscope).

  In particular, in the present embodiment, the first information recording layer 14 is irradiated with laser light to at least a portion of the system lead-in area 24A where the first prepit 42A is formed, so that the first prepit 42A The degree of modulation related to reproduction can be increased, and jitter can be improved (jitter amount can be reduced).

  Thus, the reproduction signal of the first prepit 42A in the area can be taken out with high accuracy and reliability by irradiating the system lead-in area 24A with the recording and / or reproduction laser light 36, and the optical disc 10 can be easily adapted to the corresponding standard values for various parameters such as jitter, degree of modulation, and reflectance relating to access to the laser beam 36 by the laser beam 36.

  Similarly, the degree of modulation related to reproduction of the second prepit 42B is achieved by irradiating at least a portion of the system lead-out area 24B where the second prepit 42B is formed in the second information recording layer 18. Therefore, the jitter can be improved (the amount of jitter can be reduced). As a result, the reproduction signal of the second prepit 42B in the area can be taken out with high accuracy and reliability by irradiating the system lead-out area 24B with the laser light 36, and the laser light 36 applied to the optical disk 10 Various parameters such as jitter, modulation degree, and reflectance relating to access can be easily adapted to the corresponding standard values.

  Therefore, in the optical disc 10 according to the present embodiment, it is possible to improve recording characteristics and reproduction characteristics.

  Here, a method for manufacturing the optical disc 10 according to the present embodiment will be described with reference to FIGS.

  First, in step S1 of FIG. 9, a first stamper for producing the first substrate 12 is produced. 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 12 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 12 corresponds to the system lead-in region 24A. The first stamper is manufactured by mastering the first original plate so that the first pre-pits 42A are formed at the locations to be formed and the first pre-grooves 26 are formed at the locations corresponding to the information recording area 22.

  Further, in step S2 of FIG. 9, a second stamper for manufacturing the second substrate 16 is manufactured. 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 16 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 16 corresponds to the system lead-out region 24B. A second stamper is produced by performing mastering on the second original plate so that the second pre-pits 42B are formed at the locations to be formed and the second pre-grooves 28 are formed at the locations corresponding to the information recording area 22.

  Thereafter, in step S3 of FIG. 9, the first substrate 12 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 12, and the first prepit 42A and the first pregroove 26 are formed.

  Further, in step S4 of FIG. 9, the second substrate 16 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 16 to form the second prepit 42B and the second pregroove 28.

  In the above example, the first substrate 12 and the second substrate 16 are manufactured by injection molding or extrusion molding of a resin material such as polycarbonate. However, the first substrate 12 having a flat surface as described below is used. The first prepit 42A, the first pregroove 26, the second prepit 42B, and the second pregroove 28 may be formed by forming layers on the surface of the second substrate 16, respectively.

  As a material for the 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. For example, when the first substrate 12 is formed, the layer is formed by applying a mixed liquid composed of the above-described acrylic ester and polymerization initiator on the first stamper, and further placing the first substrate 12 on the coating liquid layer. After that, the coating layer is cured by irradiating ultraviolet rays through the first substrate 12 or the first stamper to fix the first substrate 12 and the coating layer. Next, by peeling the first substrate 12 from the first stamper, it is possible to obtain the first substrate 12 with the layer having the first prepits 42A and the first pregrooves 26 fixed to the surface. The same applies to the second substrate 16, and by using the second stamper, the second substrate 16 having the surface on which the layers having the second prepits 42B and the second pregrooves 28 are fixed is obtained. Can do.

  Thereafter, in step S <b> 5 of FIG. 9, the first information recording layer 14 is formed on the surface of the first substrate 12, and then the thin first reflective layer 30 is formed on the first information recording layer 14.

  9, the second reflective layer 32 is formed on the surface of the second substrate 16, the second information recording layer 18 is then formed on the second reflective layer 32, and the second information recording is performed. A barrier layer 34 is formed on the layer 18.

  Thereafter, in step S7 of FIG. 9, the first substrate 12 and the second substrate 16 are bonded together. At this time, the first information recording layer 14 formed on the first substrate 12 and the second information recording layer 18 formed on the second substrate 16 are opposed to each other, and further, the first substrate 12 and the second substrate The intermediate layer 20 is interposed between the two and bonded together to form a bonded substrate.

  Thereafter, in step S8 of FIG. 9, the laser is applied to the portion of the first lead-in area 24A in which at least the first prepit 42A is formed in the first information recording layer 14 while relatively rotating the bonded substrate. Irradiate light. “Relative” means that the bonded substrate itself is rotated, or the laser beam irradiation source is rotated along the circumference (track direction) of the bonded substrate while the bonded substrate is fixed. To do.

  At this time, as shown in FIG. 10A, only a portion of the first information recording layer 14 corresponding to the first prepit 42A is locally irradiated with laser light having a constant output level (laser light irradiation). As shown in FIGS. 10B and 10C, the optical constant of the portion of the first information recording layer 14 irradiated with the laser light is changed (see the region 48 where the optical constant has changed).

  Or as shown to FIG. 11A, it irradiates continuously along the track in which the 1st prepit 42A was formed (refer the irradiation area 46 of a laser beam). In this case, the laser beam having a constant output level is continuously irradiated with time. As a result, as shown in FIGS. 11B and 11C, the optical constant of the portion irradiated with the laser light in the first information recording layer 14 is changed (see the region 48 where the optical constant has changed).

  This is because, by irradiating the first information recording layer 14 with laser light, the dye of the portion irradiated with the laser light in the first information recording layer 14 is decomposed and the refractive index of the portion changes. It is considered a thing.

  Therefore, the optical constant of at least the portion corresponding to the first prepit 42A in the system lead-in area 24A of the first information recording layer 14 changes, and the modulation degree related to the reproduction of the first prepit 42A can be increased. Jitter can be improved (jitter amount reduced).

  Thereafter, in step S9 of FIG. 9, the laser is applied to the portion of the system information area 24B where at least the second prepits 42B are formed in the second information recording layer 18 while relatively rotating the bonded substrate. Irradiate light.

  At this time, although not shown in the drawing, similarly to the case of the first information recording layer 14, a laser beam having a constant output level is locally applied only to the portion corresponding to the second prepit 42B in the second information recording layer 18. Irradiation may be performed, or laser light having a constant output level may be irradiated continuously along the track in which the second pre-pits 42B are formed. As a result, the optical constant of the portion irradiated with the laser light in the second information recording layer 18 changes.

  Therefore, the optical constant of the second information recording layer 18 corresponding to at least the second prepit 42B of the system lead-out area 24B changes, and the modulation degree related to reproduction of the second prepit 42B can be increased. Jitter can be improved (jitter amount reduced).

  The output level of the laser beam is preferably 3 mW or more and 10 mW or less, more preferably 4 mW or more and 6 mW or less when the recording linear velocity is 1 × speed (for example, 6.61 m / sec). When the recording linear velocity is increased and the output level of the laser beam is further increased (for example, 10 mW at a double speed), the tact time can be improved. If the output level is too low, the optical constants of the first information recording layer 14 and the second information recording layer 18 cannot be changed. If the output level is too high, the first reflective layer 30 on the first information recording layer 14 and the second reflective layer 32 on the second information recording layer 18 may be dissolved.

  The optical disc 10 according to the present embodiment is completed at the stage where the irradiation of the laser light onto the system lead-in area 24A and the system lead-out area 24B is completed.

  In the above-described example, in step S8 of FIG. 9, in the first information recording layer 14, a portion of the system lead-in area 24A where at least the first prepit 42A is formed is irradiated with laser light, and the optical portion of the portion is optically recorded. Although the constant is changed, the first information recording layer 14 of the portion may be formed with a portion whose refractive index is changed by laser light irradiation.

  That is, as shown in FIG. 12A, by irradiating only a portion of the first information recording layer 14 corresponding to the first prepit 42A with a laser beam having a constant output level, FIG. As shown in FIG. 5, a portion 50 having a changed refractive index is formed in the portion irradiated with the laser.

  Alternatively, as shown in FIG. 13A, by continuously irradiating a laser beam having a constant output level with the lapse of time along the track in which the first prepit 42A is formed, FIG. 13B and FIG. As shown to 13C, the part 50 in which the refractive index changed was formed in the part irradiated with the laser beam.

  As a result, the refractive index of the portion irradiated with the laser light (the portion 50 where the refractive index has changed) in the first information recording layer 14 changes, so that the degree of modulation related to the reproduction of the first prepit 42A is increased. Therefore, the jitter can be improved (the amount of jitter can be reduced).

  In the above-described example, in step S9 of FIG. 9, the portion of the second information recording layer 18 where at least the second pre-pits 42B are formed in the system lead-out area 24B is irradiated with laser light. However, the portion of the second information recording layer 18 in which the refractive index is changed may be formed by irradiation with laser light.

  That is, although not shown, similarly to the case of the first information recording layer 14, only a portion corresponding to the second prepit 42B in the second information recording layer 18 is locally irradiated with laser light having a constant output level. Alternatively, a laser beam having a constant output level is sequentially irradiated along the track on which the second pre-pit 42B is formed, and a refractive index is applied to a portion irradiated with the laser. A portion 50 having changed is formed. As a result, the refractive index of the portion irradiated with the laser (the portion 50 where the refractive index has changed) in the second information recording layer 18 changes, so that the degree of modulation related to the reproduction of the second prepit 42B is increased. Thus, jitter can be improved (jitter amount can be reduced).

  Next, the material and the like of each layer constituting the optical disc 10 according to the present embodiment will be described.

  First, as the first substrate 12 and the second substrate 16, 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 12 and the second substrate 16 can be manufactured by injection molding.

  Moreover, the thickness of the 1st board | substrate 12 and the 2nd board | substrate 16 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.

  In addition, the upper limit of the track pitch of the first pregroove 26 formed on the first substrate 12 and the second pregroove 28 formed on the second substrate 16 is preferably 500 nm or less, and 420 nm or less. Is more 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 width (half width) of the first pregroove 26 and the second pregroove 28 is preferably 250 nm or less, more preferably 200 nm or less, further preferably 170 nm or less, and 150 nm or less. It is particularly preferred that 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 26 and the second pregroove 28 is preferably 150 nm or less, more preferably 100 nm or less, still 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.

  As for the angle of the first pregroove 26 and the second pregroove 28, the upper limit value 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 26 and the second pregroove 28 can be arbitrarily combined.

  The values of the first pregroove 26 and the second pregroove 28 can be measured by an AFM (atomic force microscope).

  For example, the angle of the first pregroove 26 refers to the surface of the first substrate 12 before the groove is formed, and the depth of D / 10 from the surface when the groove depth of the first pregroove 26 is D. This is an angle formed by a straight line connecting the sloped portion of the groove and a sloped portion having a height of D / 10 from the deepest portion of the groove and the surface of the first substrate 12 (bottom surface of the groove portion). The same applies to the angle of the second pregroove 28.

  When the optical disk 10 according to the present embodiment is a reproduction-only optical disk, pits indicating predetermined information are formed at the same time as the first pregroove 26 and the second pregroove 28 are formed. .

  An undercoat layer is preferably formed on the surfaces of the first substrate 12 and the second substrate 16 for the purpose of improving flatness and adhesion.

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

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

  The first information recording layer 14 and the second information recording layer 18 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 14 and the second information recording layer 18 include organic compounds such as dyes and phase change metal compounds.

  Among these, the dye-type first information recording layer 14 and the second information recording layer 18 that can record information only once by the laser beam 36 are preferable. The dye-type first information recording layer 14 and the second information recording layer 18 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.

  The optical density of the dye is preferably 0.24 or more and 0.40 or less with respect to the recording wavelength of the laser beam. The dye preferably has an optical characteristic that the reflectance after recording with the laser light 36 is lower than the reflectance before recording. Thus, the first prepit 42A formed in the system lead-in area 24A and the second prepit 42B formed in the system lead-out area 24B can be reliably reproduced. That is, the reproduction information of the first prepit 42A and the second prepit 42B used for adapting parameters such as jitter, modulation degree, and reflectance to each standard value can be obtained with high accuracy. This leads to a reduction in the time taken from the start of access to the optical disc 10 to the access to the information recording area 22 of the first information recording layer 14 or the information recording area 22 of the second information recording layer 18. This is advantageous in speeding up access.

  Here, the oxonol dye used in the first information recording layer 14 and the second information recording layer 18 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 optical characteristics of the amorphous film of the dye used in the first information recording layer 14 and the second information recording layer 18 ("Oxonol dye" or "Oxonol dye described above and a dye used in combination therewith"). 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 14 and the second information recording layer 18 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 14 and the second information recording layer 18 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. The coating can be carried out by drying after coating on the surface of the substrate 12 and the surface of the second substrate 16 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 in combination as a material for the first information recording layer 14 and the second information recording layer 18, 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 14 and the second information recording layer 18 may be a single layer or a multilayer. The layer thicknesses of the first information recording layer 14 and the second information recording layer 18 are generally in the range of 20 to 500 nm, preferably in the range of 50 to 300 nm.

  Next, the first reflective layer 30 and the second reflective layer 32 will be described. The light reflective material that is the material of the first reflective layer 30 and the second reflective layer 32 is a material that has a high reflectance with respect to the laser light 36. Examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Examples thereof include metals such as Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, and Bi, and semimetals or 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 first reflective layer 30 and the second reflective layer 32 can be formed on the first information recording layer 14 and the second substrate 16 by evaporating, sputtering, or ion plating the reflective material, for example.

  And it is preferable that the layer thickness of the 1st reflection layer 30 exists in the range of 2-150 nm. The layer thickness of the second reflective layer 32 is generally in the range of 10 to 300 nm, preferably in the range of 50 to 200 nm.

  Next, the barrier layer 34 is provided for the purpose of physically and chemically protecting the second information recording layer 18 and the like. The barrier layer 34 is provided in the first substrate 12 and the second substrate 16 in a portion where the first information recording layer 14 and the second information recording layer 18 are not provided for the purpose of improving scratch resistance and moisture resistance. May be.

Examples of the material used for the barrier layer 34 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 34 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 an appropriate solvent, and then applying the coating solution and curing it by irradiating 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 34 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 14 and the second information recording layer 18.

Examples of the material for the intermediate layer 20 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.

  Here, in Examples 1 to 4, before the laser beam is irradiated to at least a portion where the first pre-pit 42A of the system lead-in area 24A is formed in the first information recording layer 14, and the laser beam. The degree of modulation and jitter related to the reproduction of the first prepit 42A after irradiation of the first prepit 42A are measured.

  Each of Examples 1 to 4 is manufactured according to the manufacturing method according to the present embodiment described above, and the different parameter is the half-value width W1 of the first prepit 42A formed in the system lead-in area 24A. is there. The half-value width W1 indicates the half-value width of a protrusion (projection for forming the first prepit 42A) formed on the first stamper.

  FIG. 14 shows the measurement results of the half width W1 of the first prepit 42A and the degree of modulation and jitter related to reproduction of the first prepit 42A before irradiating the laser beam and after irradiating the laser beam in Examples 1 to 4. .

  Laser light irradiation is performed by continuously irradiating a laser beam having an output level (6 mW) that is constant over time along the track on which the first pre-pits 42A are formed, while rotating the bonded substrate. I tried to do it.

  The following can be understood from the results shown in FIG.

  In Example 1 (half-value width W1 = 205 nm of the first prepit 42A), when the first prepit 42A is reproduced by the recording and / or reproducing laser light 36 before the laser light irradiation, the modulation degree is a standard value. The jitter was 0.28 below (minimum value = 0.30), and the jitter was 7.9% close to the standard value (maximum value = 8.0%). However, as shown in step S8 of FIG. 9, in the case where the optical constant of the portion corresponding to the first prepit 42A in the first information recording layer 14 is changed by irradiation with laser light, recording and / or Alternatively, when the first prepit 42A is reproduced by the reproduction laser beam 36, the modulation degree is 0.52 exceeding the standard value (minimum value = 0.30), and the jitter is also improved to 6.9%. .

  In Example 2 (half-value width W1 = 215 nm of the first prepit 42A), when the first prepit 42A is reproduced by the recording and / or reproduction laser light 36 before the laser light irradiation, the modulation degree is a standard value. The jitter was 0.29 below (minimum value = 0.30), and the jitter was 7.8% close to the standard value (maximum value = 8.0%). However, as shown in step S8 of FIG. 9, in the case where the optical constant of the portion corresponding to the first prepit 42A in the first information recording layer 14 is changed by irradiation with laser light, recording and / or Alternatively, when the first prepit 42A is reproduced by the reproduction laser beam 36, the modulation degree is 0.51 exceeding the standard value (minimum value = 0.30), and the jitter is also improved to 5.8%. .

  In Example 3 (half-value width W1 = 244 nm of the first prepit 42A), when the first prepit 42A is reproduced by the recording and / or reproduction laser light 36 before the laser light irradiation, the modulation degree is a standard value. It was 0.30, the same as (minimum value = 0.30), and the jitter was 10.1%, significantly exceeding the standard value (maximum value = 8.0%). However, as shown in step S8 of FIG. 9, in the case where the optical constant of the portion corresponding to the first prepit 42A in the first information recording layer 14 is changed by irradiation with laser light, recording and / or Alternatively, when the first prepit 42A is reproduced by the reproduction laser beam 36, the modulation degree is 0.52 exceeding the standard value (minimum value = 0.30), and the jitter is greatly improved to 5.3%. ing.

  In Example 4 (half-value width W1 = 283 nm of the first prepit 42A), when the first prepit 42A is reproduced by the recording and / or reproduction laser light 36 before the laser light irradiation, the modulation degree is a standard value. The jitter was 0.31 which was slightly larger than (minimum value = 0.30), and jitter could not be measured. However, as shown in step S8 of FIG. 9, in the case where the optical constant of the portion corresponding to the first prepit 42A in the first information recording layer 14 is changed by irradiation with laser light, recording and / or Alternatively, when the first prepit 42A is reproduced by the reproduction laser beam 36, the modulation degree is 0.54 exceeding the standard value (minimum value = 0.30), and the jitter is greatly improved to 5.3%. ing.

  Thus, before the laser beam irradiation (before changing the optical constant of the first information recording layer 14), the modulation degree related to the reproduction of the first prepit 42A was low and the jitter was high, whereas the laser beam After the irradiation (after changing the optical constant of the first information recording layer 14), it can be seen that the degree of modulation related to the reproduction of the first prepit 42A increases and the jitter is improved.

  In the example described above, the example is applied to the optical disc 10 having two information recording layers (the first information recording layer 14 and the second information recording layer 18). The present invention can also be applied to the optical disc of the first information recording layer 14 only).

  In addition, the manufacturing method of the optical information recording medium according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

It is a figure for demonstrating the information recording area of the optical disk based on this Embodiment, a system lead-in area | region, and a system lead-out area | region. It is sectional drawing which abbreviate | omits and shows some information recording areas in the optical disk which concerns on this Embodiment. It is a partially omitted sectional view showing a first substrate of an optical disc according to the present embodiment together with a first information recording layer and a first reflective layer. It is a partially omitted sectional view showing a second substrate of the optical disc according to the present embodiment together with a second information recording layer and a second reflective layer. It is a top view which abbreviate | omits and shows some system lead-in area | regions of the optical disk based on this Embodiment. It is sectional drawing on the VI-VI line in FIG. It is a top view which abbreviate | omits and shows some system lead-out area | regions of the optical disk based on this Embodiment. It is sectional drawing on the VIII-VIII line in FIG. It is process block diagram which shows an example of the manufacturing method of the optical disk which concerns on this Embodiment. FIG. 10A shows a state in which a laser beam having a constant output level is locally irradiated for the purpose of changing the optical constant of the portion corresponding to the first prepit in the first information recording layer. 10B is a cross-sectional view taken along line XB-XB in FIG. 10A, and FIG. 10C is a cross-sectional view taken along line XC-XC in FIG. 10A. In FIG. 11A, a laser beam having a constant output level is continuously applied along the track on which the first prepit is formed in order to change the optical constant of the portion corresponding to the first prepit in the first information recording layer. FIG. 11B is a cross-sectional view taken along line XIB-XIB in FIG. 11A, and FIG. 11C is a cross-sectional view taken along line XIC-XIC in FIG. 11A. FIG. 12A shows a state in which a laser beam having a constant output level is locally irradiated for the purpose of changing the optical constant of the portion corresponding to the first prepit in the first information recording layer. 12B is a cross-sectional view taken along line XIIB-XIIB in FIG. 12A, and FIG. 12C is a cross-sectional view taken along line XIIC-XIIC in FIG. 12A. FIG. 13A shows a laser beam having a constant output level continuously along the track on which the first prepit is formed for the purpose of changing the optical constant of the portion corresponding to the first prepit in the first information recording layer. FIG. 13B is a cross-sectional view taken along the line XIIIB-XIIIB in FIG. 13A, and FIG. 13C is a cross-sectional view taken along the line XIIIC-XIIIC in FIG. 13A. It is a table | surface figure which shows the half width of the 1st prepit in Examples 1-4, and the measurement result of the modulation | alteration and jitter which concern on reproduction | regeneration of the 1st prepit before irradiating a laser beam and after irradiating a laser beam. It is a general characteristic diagram showing a change in the amount of jitter with respect to the thickness of the reflective layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Optical disk 12 ... 1st board | substrate 14 ... 1st information recording layer 16 ... 2nd board | substrate 18 ... 2nd information recording layer 22 ... Information recording area 24A ... System lead-in area 24B ... System lead-out area 26 ... 1st Pre-groove 28 ... second pre-groove 42A ... first pre-pit 42B ... second pre-pits 44, 46 ... irradiation region 48 of laser light 48 ... region where optical constant has changed 50 ... part where refractive index has changed

Claims (20)

In a method of manufacturing an optical information recording medium comprising a substrate and a recording layer formed on the substrate, and recording and / or reproducing information by irradiating the recording layer with a laser beam.
A pit forming step for forming one or more pits used to adjust at least the output of the laser beam to the recording layer on the innermost peripheral portion of the substrate;
A recording layer forming step of forming the recording layer on the substrate;
A method of manufacturing an optical information recording medium, comprising: a laser beam irradiation step of irradiating a laser beam to the innermost peripheral portion of the recording layer where the pits are formed. In the manufacturing method of the optical information recording medium of Claim 1,
The step of irradiating the laser beam with respect to the recording layer of the innermost peripheral portion for the purpose of changing an optical constant of the recording layer of the innermost peripheral portion of the recording layer where the pits are formed. And irradiating with laser light. In the manufacturing method of the optical information recording medium of Claim 2,
The optical constant of the recording layer in the innermost peripheral portion is set by continuing to irradiate the innermost peripheral portion with the laser light having a constant output level over time while relatively rotating the substrate. A method for manufacturing an optical information recording medium, characterized by being changed. In a method of manufacturing an optical information recording medium comprising a substrate and a recording layer formed on the substrate, and recording and / or reproducing information by irradiating the recording layer with a laser beam.
A pit forming step for forming one or more pits used to adjust at least the output of the laser beam to the recording layer on the innermost peripheral portion of the substrate;
A recording layer forming step of forming the recording layer on the substrate;
An optical information recording medium manufacturing method comprising: an optical constant changing step of changing an optical constant of a recording layer corresponding to the pit among the recording layers. In the manufacturing method of the optical information recording medium of Claim 4,
In the optical constant recording step, the optical constant of the recording layer filled in the pit is changed. In the manufacturing method of the optical information recording medium of Claim 4 or 5,
The optical constant changing step irradiates the innermost peripheral portion of the substrate where the pits are formed with laser light for the purpose of changing the optical constant of the recording layer. A method for manufacturing a recording medium. In the manufacturing method of the optical information recording medium of Claim 6,
The optical constant of the recording layer is changed by continuously irradiating the innermost peripheral portion with the laser beam having a constant output level as time elapses while relatively rotating the substrate. A method for manufacturing an optical information recording medium. In the manufacturing method of the optical information recording medium of Claim 3 or 7,
The method for manufacturing an optical information recording medium, wherein the output level is 3 mW or more and 10 mW or less when the recording linear velocity is 1 × speed. In the manufacturing method of the optical information recording medium of any one of Claims 1-8,
The method for producing an optical information recording medium, wherein in the recording layer forming step, a dye to be the recording layer is applied on the substrate. In the manufacturing method of the optical information recording medium of any one of Claims 1-9,
In the optical information recording medium, the wavelength of the recording and / or reproducing laser light is 405 nm, the numerical aperture of the objective lens for condensing the laser light on the recording layer is 0.65, and the end face of the optical information recording medium A method for producing an optical information recording medium, wherein the distance from the recording layer to the recording layer corresponds to 0.6 mm. A first substrate and a second substrate;
A first recording layer formed on the first substrate;
A second recording layer formed on the second substrate, and the first recording layer and the second recording layer are in this order as viewed from the direction of irradiation with the recording and / or reproducing laser light. In a method of manufacturing an optical information recording medium that is arranged and records and / or reproduces information by irradiating at least the first recording layer with a laser beam,
A first pit forming step for forming one or more first pits used for adjusting at least the output of the laser beam to the first recording layer in the innermost peripheral portion of the first substrate;
A first recording layer forming step of forming the first recording layer on the first substrate;
A second pit forming step for forming one or more second pits used to adjust at least the output of the laser beam to the second recording layer in the innermost peripheral portion of the second substrate;
A second recording layer forming step of forming the second recording layer on the second substrate;
A bonding step of bonding the second substrate on the first substrate so that the first recording layer and the second recording layer face each other;
A first laser beam irradiation step of irradiating a laser beam to the innermost peripheral portion in which the first pit is formed in the first recording layer;
A method of manufacturing an optical information recording medium, comprising: a second laser beam irradiation step of irradiating a laser beam to the innermost peripheral portion of the second recording layer in which the second pit is formed. . In the manufacturing method of the optical information recording medium of Claim 11,
In the first laser beam irradiation step, for the purpose of changing an optical constant of the first recording layer in the innermost peripheral portion of the first recording layer where the first pit is formed, Irradiating the first recording layer in the peripheral portion with laser light;
For the purpose of changing the optical constant of the second recording layer in the innermost peripheral portion of the second recording layer in which the second pit is formed, the second laser beam irradiation step is performed. A method of manufacturing an optical information recording medium, comprising irradiating a laser beam onto the second recording layer in a peripheral portion. In the manufacturing method of the optical information recording medium of Claim 12,
In the first laser beam irradiation step, the innermost peripheral portion of the first substrate is irradiated with the laser beam having a constant output level as time passes while relatively rotating the optical information recording medium. Subsequently, the optical constant of the first recording layer in the innermost peripheral portion is changed,
In the second laser beam irradiation step, the innermost peripheral portion of the second substrate is irradiated with the laser beam having a constant output level as time passes while relatively rotating the optical information recording medium. A method of manufacturing an optical information recording medium, wherein the optical constant of the second recording layer in the innermost peripheral portion is continuously changed. A first substrate and a second substrate;
A first recording layer formed on the first substrate;
A second recording layer formed on the second substrate, and the first recording layer and the second recording layer are in this order as viewed from the direction of irradiation with the recording and / or reproducing laser light. In a method of manufacturing an optical information recording medium that is arranged and records and / or reproduces information by irradiating at least the first recording layer with a laser beam,
A first pit forming step for forming one or more first pits used for adjusting at least the output of the laser beam to the first recording layer in the innermost peripheral portion of the first substrate;
A first recording layer forming step of forming the first recording layer on the first substrate;
A second pit forming step for forming one or more second pits used to adjust at least the output of the laser beam to the second recording layer in the innermost peripheral portion of the second substrate;
A second recording layer forming step of forming the second recording layer on the second substrate;
A bonding step of bonding the second substrate on the first substrate so that the first recording layer and the second recording layer face each other;
A first optical constant changing step of changing an optical constant of the recording layer corresponding to the first pit in the first recording layer;
A method of manufacturing an optical information recording medium, comprising: a second optical constant changing step of changing an optical constant of the recording layer corresponding to the second pit in the second recording layer. In the manufacturing method of the optical information recording medium of Claim 14,
In the first optical constant changing step, the optical constant of the first recording layer filled in the first pit is changed,
The method of manufacturing an optical information recording medium, wherein the second optical constant changing step changes an optical constant of a second recording layer filled in the second pit. In the manufacturing method of the optical information recording medium of Claim 14 or 15,
The first optical constant changing step irradiates a laser beam for the purpose of changing an optical constant of a recording layer to the innermost peripheral portion of the first substrate where the first pit is formed,
The second optical constant changing step irradiates a laser beam for the purpose of changing the optical constant of the recording layer to the innermost peripheral portion of the second substrate where the second pit is formed. An optical information recording medium manufacturing method characterized by the above. In the manufacturing method of the optical information recording medium of Claim 16,
In the first optical constant changing step, the innermost peripheral portion of the first substrate is irradiated with the laser light having a constant output level as time passes while relatively rotating the optical information recording medium. Subsequently, the optical constant of the first recording layer corresponding to the first pit is changed,
In the second optical constant changing step, the innermost peripheral portion of the second substrate is irradiated with the laser beam having a constant output level as time passes while relatively rotating the optical information recording medium. A method of manufacturing an optical information recording medium, wherein the optical constant of the second recording layer corresponding to the second pit is continuously changed. In the manufacturing method of the optical information recording medium of Claim 13 or 17,
The method for manufacturing an optical information recording medium, wherein the output level is 3 mW or more and 10 mW or less when the recording linear velocity is 1 × speed. In the manufacturing method of the optical information recording medium of any one of Claims 11-18,
In the first recording layer forming step, a dye to be the first recording layer is applied on the first substrate,
The method of manufacturing an optical information recording medium, wherein the second recording layer forming step includes applying a dye to be the second recording layer on the second substrate. In the manufacturing method of the optical information recording medium of any one of Claims 11-19,
In the optical information recording medium, the wavelength of the recording and / or reproducing laser light is 405 nm, the numerical aperture of the objective lens for condensing the laser light on at least the first recording layer is 0.65, and the optical information recording A method for producing an optical information recording medium, wherein a distance from an end face of the medium to the first recording layer corresponds to 0.6 mm.

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