JP2006120221A - Method for manufacturing optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical recording medium by which the optical recording medium having a spacer layer whose thickness is very thin can be desirably manufactured. <P>SOLUTION: The method for manufacturing the optical recording medium including a step wherein a resin stamper 10 having a recessed part 33 formed in a position corresponding to the projecting part 53 of a substrate 2 is made to be opposed to the substrate 2 wherein the projecting part 53 is formed on the inner side of a data recording region and an information layer is formed in the data recording region and a UV curing resin is sandwiched by the substrate 2 and the resin stamper 10 and a step wherein the UV curing resin between the resin stamper 10 and the substrate 2 is cured by irradiation with UV to form the spacer layer is characterized in that the height x of the projecting part 53 of the substrate 2 satisfies a condition of x≤y+D when the thickness of the spacer layer and the depth of the recessed part 33 formed in the resin stamper 10 are defined as D and y, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium manufacturing method for manufacturing an optical recording medium in which a plurality of information layers are laminated via a spacer layer. More specifically, the present invention relates to an extremely thin spacer layer. The present invention relates to a method of manufacturing an optical recording medium that can be formed as desired.

  Conventionally, optical recording media represented by CDs and DVDs are widely used as recording media for recording digital data. In manufacturing these optical recording media, a substrate having grooves and lands formed on the surface is first created. Such a substrate is formed by setting a metal stamper having irregularities corresponding to the shape of the groove or land to be formed on the surface of the substrate in a mold and filling the mold with resin by an injection molding method. The

  FIG. 16 is a schematic cross-sectional view showing a schematic configuration of a mold.

  As shown in FIG. 16, the mold 100 includes a fixed mold 101 and a movable mold 102, and is configured such that resin flows from the fixed mold 101 side.

  The fixed mold 101 includes, in order from the center of the mold 100, a sprue bush 103 that forms a resin inflow path, an inner peripheral holder 105 that locks the metal stamper 104, and a mirror block 106 on which the metal stamper 104 is placed. And an outer peripheral holder 107 that faces the outer peripheral portion of the mirror block 106 and holds the metal stamper 104 together with the inner peripheral holder 105.

  A protrusion protruding toward the outer peripheral side is formed at the tip of the inner peripheral holder 105, and a notch is formed at the front end of the outer peripheral holder 107 on the inner peripheral side. The inner peripheral portion and the outer peripheral portion of the metal stamper 104 are locked by the protrusions formed at the distal ends of the inner peripheral holder 105 and the notches formed at the distal ends of the outer peripheral holder 107, respectively. 104 is fixed to the surface of the mirror block 106.

  The movable mold 102 includes, in order from the center of the mold 100, a cut punch 108 for separating the resin filled in the inflow path, and a mirror block 109 that forms the back surface of the substrate 110.

  Further, a cavity corresponding to the thickness of the substrate 110 to be formed is formed between the fixed mold 101 and the movable mold 102, and the resin flowing from the fixed mold 101 is filled in this cavity. As a result, the substrate 110 onto which the irregularities on the surface of the metal stamper 104 are transferred is formed.

  On the other hand, in recent years, development of next-generation optical recording media having a larger capacity and a higher data transfer rate has been actively conducted.

  In such a next-generation optical recording medium, the data recording density is increased by reducing the wavelength λ of the laser beam, increasing the numerical aperture NA of the objective lens, and reducing the beam spot diameter of the laser beam. I am doing so.

  Apart from the method of reducing the beam spot diameter of the laser beam, the development of an optical recording medium that increases the recording capacity by increasing the number of information layers and increasing the area of the recording surface for recording data is also being promoted. For example, Patent Document 1 proposes an optical recording medium having a structure in which a plurality of information layers are stacked.

  In the optical recording medium described in the patent document, two layers of information layers including a laminated body in which a reflective film, a dielectric film, a recording film, and a dielectric film are laminated in this order are provided. . Between these two information layers, a spacer layer is formed for the purpose of physically separating each information layer, and grooves and lands are formed on the surface of the spacer layer in the same manner as the surface of the substrate. . Grooves and lands formed on the surface of the spacer layer function as laser beam guide tracks in the same manner as the grooves and lands formed on the substrate.

Unlike a substrate formed using a metal stamper and a mold, such a spacer layer having irregularities on the surface is obtained by applying a resin stamper formed using a metal stamper and a mold to a resin layer applied on the information layer. Or formed by covering the resin discharged on the information layer with a resin stamper, rotating the substrate in that state, and spin-coating the resin.
JP 2003-242676 A

  In order to form a spacer layer having a predetermined thickness, the distance between the information layer and the resin stamper is reduced by the thickness of the spacer layer to be formed by hardening shrinkage or by the centrifugal force generated by rotation. It is necessary to bring the substrate and the resin stamper close to each other until the thickness becomes the same as the thickness of the substrate.

  On the other hand, even in next-generation optical recording media, attempts have been made to further increase the recording capacity by forming a plurality of information layers. In such next-generation optical recording media, From such a viewpoint, it is required to form a very thin spacer layer having a thickness of 5 μm to 40 μm.

  However, when assembling the mold, the assembly position of the sprue bushing 103 and the inner peripheral holder 105 is not strictly adjusted. Therefore, it is extremely rare that the tips of the sprue bushing 103 and the inner peripheral holder 105 are flush with each other. Usually, as shown in FIG. 16, large protrusions are formed on the innermost peripheral portion of the substrate and the resin stamper.

  Therefore, when an extremely thin spacer layer is formed, the protrusion formed on the substrate and the protrusion formed on the resin stamper before the distance between the information layer and the resin stamper reaches a predetermined distance. And the substrate and the resin stamper cannot be brought closer to each other, and it is extremely difficult to form a very thin spacer layer.

  Accordingly, an object of the present invention is to provide an optical recording medium manufacturing method capable of forming an optical recording medium having a very thin spacer layer as desired.

  The object of the present invention is that a convex portion is formed inside the data recording area, and a concave portion is formed at a position corresponding to the convex portion of the substrate on the substrate on which the information layer is formed in the data recording area. A step of sandwiching a radiation curable resin with the substrate and the resin stamper, and irradiating with radiation to cure the radiation curable resin between the resin stamper and the substrate; Forming the spacer layer, wherein the thickness of the spacer layer is D, and the depth of the concave portion formed in the resin stamper is y, the height x of the convex portion of the substrate satisfies the condition x ≦ y + D It is achieved by a method for manufacturing an optical recording medium, characterized by being formed so as to satisfy.

  According to the present invention, since the concave portion is formed on the surface of the resin stamper and the convex portion is formed on the surface of the substrate at a position corresponding to the concave portion of the resin stamper, the resin stamper is brought closer to the substrate. At this time, the convex portion formed on the substrate enters the concave portion formed on the resin stamper.

  Further, according to the present invention, the height x of the convex portion formed on the substrate is not more than the size y + D obtained by adding the thickness D of the spacer layer to the depth y of the concave portion formed on the resin stamper. Since the distance between the information layer formed on the substrate and the resin stamper is the same as the thickness of the spacer layer to be formed plus a predetermined thickness, the resin stamper and the substrate are brought closer to each other. In this case, it is possible to prevent the substrate and the resin stamper from contacting each other.

  Therefore, the information layer formed on the substrate and the resin stamper can be made sufficiently close to each other, and a very thin spacer layer can be formed as desired.

  In a preferred embodiment of the present invention, the method further includes a step of discharging a radiation curable resin onto the substrate on which the information layer is formed, and the height x of the convex portion of the substrate is changed from x to the thickness D of the spacer layer. Is formed so as to satisfy the condition of ΔD / D ≦ 0.5.

  For example, when a radiation curable resin is spread on the surface of a substrate on which an information layer is formed by spin coating using centrifugal force, radiation curing is applied to the portion where the convex portion of the substrate is formed. In the preferred embodiment of the present invention, the height of the convex portion satisfies the condition of ΔD / D ≦ 0.5. Since it is formed so as to be filled and lower than a predetermined height, it is possible to prevent entrainment of the radiation curable resin, etc., and to prevent bubbles from being generated in the radiation curable resin. It becomes possible to prevent.

  In another preferred embodiment of the present invention, the method further includes a step of discharging a radiation curable resin onto the resin stamper, and the depth y of the concave portion of the resin stamper is determined from y to the thickness D of the spacer layer. Is formed so as to satisfy the condition of ΔD / D ≦ 0.5.

  According to another preferred embodiment of the present invention, it is possible to prevent entrainment of the radiation curable resin that occurs when the radiation curable resin is spread on the surface of the resin stamper. Can be prevented from occurring.

  In the present invention, it is more preferable to discharge the radiation curable resin from the substrate on which the information layer is formed or the low portion of the resin stamper to the high portion.

  When bubbles are generated in the radiation curable resin when the radiation curable resin is spread on the substrate on which the information layer is formed or on the resin stamper, these bubbles are particularly affected by each step portion of the substrate or the resin stamper. However, according to a further preferred embodiment of the present invention, it is possible to effectively prevent bubbles from remaining in each step portion of the substrate or the resin stamper.

  Further, the object of the present invention is to form a concave portion on the inner side of the data recording area, and to form a convex portion at a position corresponding to the concave portion of the substrate on the substrate on which the information layer is formed in the data recording area. A step of sandwiching a radiation curable resin with the substrate and the resin stamper, and irradiating with radiation to cure the radiation curable resin between the resin stamper and the substrate; The height of the convex portion of the resin stamper satisfies the condition of y ≦ x + D, where D is the thickness of the spacer layer and x is the depth of the concave portion of the substrate. This is achieved by a method of manufacturing an optical recording medium characterized by being formed.

  According to the present invention, a convex portion is formed on the surface of the resin stamper, a concave portion is formed on the surface of the substrate at a position corresponding to the convex portion of the resin stamper, and the convex portion formed on the resin stamper. Is not larger than the depth x + D obtained by adding the thickness D of the spacer layer to the depth x of the concave portion formed in the substrate, so that the information layer formed on the substrate Even when the resin stamper is brought close to the substrate until the distance from the resin stamper reaches a predetermined distance, the substrate and the resin stamper can be prevented from contacting each other.

  In a preferred embodiment of the present invention, the method further includes a step of discharging a radiation curable resin onto the substrate on which the information layer is formed, and the depth x of the concave portion of the substrate is changed from x to the thickness D of the spacer layer. When the subtracted value is ΔD, it is formed so as to satisfy the condition of ΔD / D ≦ 0.5.

  Further, in another preferred embodiment of the present invention, the method further includes a step of discharging a radiation curable resin onto the resin stamper, wherein the height y of the convex portion of the resin stamper is from y to the thickness of the spacer layer. It is formed so as to satisfy the condition of ΔD / D ≦ 0.5 when ΔD is obtained by subtracting D.

  Furthermore, the object of the present invention is to form a recess at a position corresponding to the recess of the substrate on the substrate in which the information layer is formed in the data recording area, while the recess is formed inside the data recording area. A step of sandwiching a radiation curable resin with the substrate and the resin stamper, and irradiating with radiation to cure the radiation curable resin between the resin stamper and the substrate; And forming the optical recording medium.

  According to the present invention, since the concave portion is formed on the surface of the resin stamper and the concave portion is formed on the surface of the substrate at a position corresponding to the concave portion of the resin stamper, the information layer formed on the substrate Even when the resin stamper is brought close to the substrate until the distance from the resin stamper reaches a predetermined distance, the substrate and the resin stamper can be prevented from contacting each other.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the manufacturing method of the optical recording medium which can form the optical recording medium which has a very thin spacer layer as desired.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view of an optical recording medium according to a preferred embodiment of the present invention, and FIG. 2 is a schematic enlarged sectional view of a portion indicated by A in FIG.

  As shown in FIG. 1, the optical recording medium 1 has a disk shape, and a center hole 7 for setting the optical recording medium 1 in a data recording / reproducing apparatus is formed at the center thereof.

  The optical recording medium 1 shown in FIGS. 1 and 2 has an objective NA having a numerical aperture NA satisfying λ / NA ≦ 640 nm by a laser beam having a wavelength of 380 nm to 450 nm from the direction indicated by the arrow in FIG. The data is reproduced by being irradiated through a lens (not shown).

  As shown in FIG. 2, the optical recording medium 1 according to this embodiment includes a substrate 2, a first information layer 3 formed on the substrate 2, and a spacer formed on the first information layer 3. A layer 4, a second information layer 5 formed on the spacer layer 4, and a light transmission layer 6 formed on the second information layer 5 are provided.

  The substrate 2 functions as a mechanical support for the optical recording medium 1. The material for forming the substrate 2 is not particularly limited as long as it can function as a support for the optical recording medium 1. For example, a polycarbonate resin, an olefin resin, or the like can be used. The thickness of the substrate 2 is not particularly limited, but is preferably about 1.1 mm.

  Grooves 2a and lands 2b are formed on the surface of the substrate 2, and these grooves 2a and lands 2b serve as laser beam guide tracks when data is recorded on and reproduced from the first information layer 3. Function.

  The first information layer 3 is a data recording layer, and is a write-once recording film containing organic dyes such as cyanine dyes, phthalocyanine dyes, azo dyes, porphyrin dyes as main components, or Ge- It is composed of a phase change type recording film containing a phase change material such as Sb—Te, In—Sb—Te, Sn—Se—Te, Ge—Te—Sn, In—Se—Tl as a main component.

  Further, the first information layer 3 does not necessarily need to be configured only by the recording film, and other materials such as a dielectric film and a reflective film may be formed on the front surface, the back surface, or both of the recording film as necessary. A layer may be formed.

  The spacer layer 4 has a function of protecting the surface of the first information layer 3 and separating the first information layer 3 and the second information layer 5 from each other with a sufficient physical and optical distance. Yes.

  Since the laser beam passes through the spacer layer 4, it is required that the optical absorption and reflection in the wavelength region of 380 nm to 450 nm, which is the wavelength region of the used laser beam, is small, and that the birefringence is small. It is formed. The thickness of the spacer layer 4 is preferably 5 μm to 40 μm, and more preferably 10 μm to 30 μm.

  In addition, grooves 4a and lands 4b are formed on the surface of the spacer layer 4, and these grooves 4a and lands 4b are used to guide laser beams when recording and reproducing data on the second information layer 5. Function as.

  Similar to the first information layer 3, the second information layer 5 is a layer in which data is recorded, and has the same configuration as the first information layer 3. The second information layer 5 is preferably formed thinner than the first information layer 3 because the laser beam is transmitted when data is recorded on and reproduced from the first information layer 3. .

  The light transmission layer 6 constitutes a light incident surface of the laser beam and has a function of protecting the surface of the second information layer 5.

  Like the spacer layer 4, the light transmission layer 6 is optically transparent, requires little optical absorption and reflection in the wavelength region of the laser beam used, 380 nm to 450 nm, and has low birefringence. For example, it is formed of an ultraviolet curable resin. The thickness of the light transmission layer 6 is preferably 30 μm to 200 μm.

  The optical recording medium 1 having the above configuration is manufactured as follows.

  In manufacturing the optical recording medium 1, a resin stamper for forming the spacer layer 4 is manufactured prior to manufacturing the optical recording medium 1 body.

  In producing the resin stamper, first, a metal stamper having a concavo-convex corresponding to grooves and lands formed on its surface is manufactured by a mastering process using a photoresist master having a concavo-convex pattern formed thereon.

  Next, after the central portion of the metal stamper is punched out, the metal stamper is set in a mold, and a resin stamper is formed by an injection molding method.

  FIG. 3 is a schematic cross-sectional view showing a schematic configuration of a mold for forming a resin stamper.

  As shown in FIG. 3, the mold 20 for forming the resin stamper 10 includes a fixed mold 21 and a movable mold 22, and is configured such that resin flows in from the fixed mold 21 side.

  The fixed mold 21 includes, in order from the center of the mold 20, a sprue bush 23 that forms a resin inflow path, an inner peripheral holder 24 that locks the metal stamper 11, and a mirror block 25 on which the metal stamper 11 is placed. And an outer peripheral holder 26 for locking the metal stamper 11 together with the inner peripheral holder 24 at a position facing the outer peripheral portion of the mirror block 25.

  The movable mold 22 includes, in order from the center of the mold 20, a cut punch 29 for separating the resin filled in the inflow path and a mirror block 30 that forms the back surface of the resin stamper 10.

  In the present embodiment, the mold 20 has an intake pipe 27 formed on the mirror block 25 of the fixed mold 21, and the inner peripheral holder 24 is different from the conventional mold 100 shown in FIG. The protruding portion is not formed, and the side surface is formed flush.

  Further, in the present embodiment, the fixed mold 21 of the mold 20 is arranged so that the tip of the inner peripheral holder 24 is positioned below the surface of the metal stamper 11, and the tip of the sprue bush 23 is The inner peripheral holder 24 is formed so as to be positioned below the tip. For this reason, a first convex step 28 a and a second convex step 28 b are formed in the fixed mold 21 in order from the center of the fixed mold 21.

  In the mold 20, a cavity corresponding to the thickness of the resin stamper 10 to be formed is formed between the fixed mold 21 and the movable mold 22, and the resin flowing from the fixed mold 21 is filled in the cavity. Thus, the resin stamper 10 to which the unevenness on the surface of the metal stamper 11 is transferred is produced.

  FIG. 4 is a schematic cross-sectional view of the resin stamper 10 formed using the mold 20.

  As shown in FIG. 4, the resin stamper 10 includes a first concave portion 32 and a second concave portion 28 b corresponding to the first convex step 28 a and the second convex step 28 b formed on the fixed die 21 of the mold 20. A second recess 33 is formed. The first concave portion 32 and the second concave portion 33 are formed so that the first convex step 28 a and the second convex step 28 b of the fixed mold 21 are formed inside the metal stamper 11. Of the surface, it is formed inside the region 31 corresponding to the data recording region.

  Thus, when the resin stamper 10 is formed, the manufacture of the optical recording medium 1 main body is started. In manufacturing the optical recording medium 1 main body, first, the metal stamper 11 is set in the mold 40, and the substrate 2 is formed by an injection molding method.

  FIG. 5 is a schematic cross-sectional view showing a schematic configuration of a mold 40 for forming the substrate 2.

  As shown in FIG. 5, the mold 40 for forming the substrate 2 includes a fixed mold 41 and a movable mold 42, and is configured such that resin flows from the fixed mold 41 side.

  The fixed die 41 includes a sprue bush 43, an inner peripheral holder 44, a mirror surface block 45 having a plurality of intake pipes 47, and an outer peripheral holder 46. The movable die 42 includes a cut punch 49, a mirror surface block 50, and the like. It is composed of

  In the present embodiment, the mold 40 for forming the substrate 2 is such that the tip of the inner peripheral holder 44 is located above the surface of the metal stamper 11 and the tip of the sprue bush 43 is the tip of the inner peripheral holder 44. It is formed so as to be positioned above the tip. For this reason, in the fixed mold 41, the first concave step 48 a and the second concave step are formed in order from the center of the fixed mold 41, contrary to the fixed mold 21 of the mold 20 for forming the resin stamper 10. 48b is formed. The first concave step 48a and the second concave step 48b are formed at positions corresponding to the first convex step 28a and the second convex step 28b formed on the fixed mold 21 of the mold 20, respectively. Yes.

  In the mold 40, a cavity corresponding to the thickness of the substrate 2 to be formed is formed between the fixed mold 41 and the movable mold 42, and the resin flowing in from the fixed mold 41 is filled in the cavity. As a result, the substrate 2 to which the irregularities on the surface of the metal stamper 11 are transferred is formed.

  FIG. 6 is a schematic cross-sectional view of the substrate 2 formed using the mold 40.

  As shown in FIG. 6, the first convex portion 52 and the second convex portion are formed on the substrate 2 corresponding to the first concave step 48 a and the second concave step 48 b formed in the mold 40. 53 is formed. Further, as described above, the first concave step 48 a and the second concave step 48 b of the mold 40 are positions corresponding to the first convex step 28 a and the second convex step 28 b formed in the mold 20. Therefore, the first convex portion 52 and the second convex portion 53 are formed at positions corresponding to the first concave portion 32 and the second concave portion 33 formed in the resin stamper 10, respectively. Yes.

  FIG. 7 is a schematic enlarged cross-sectional view showing the first concave portion 32 and the second concave portion 33 formed in the resin stamper 10, and the first convex portion 52 and the second convex portion 53 formed in the substrate 2. It is.

  As shown in FIG. 7, the first convex portion 52 formed on the substrate 2 is formed such that the height x1 is equal to or less than the depth y1 of the first concave portion 32 formed in the resin stamper 10. The side surface 52s is formed so as to be located inside the side surface 32s of the first recess 32 formed in the resin stamper 10.

  The first convex portion 52 formed on the substrate 2 has a thickness D of the spacer layer 4 and ΔD1 obtained by subtracting the thickness D of the spacer layer 4 from the height x1 of the first convex portion 52. In this case, ΔD1 / D is formed at a height that is 0.5 or less. Therefore, for example, when the thickness of the spacer layer 4 is 25 μm, the first convex portion 52 is formed with a height of 37.5 μm or less.

  On the other hand, the second convex portion 53 formed on the substrate 2 has a height x2 obtained by adding the thickness D of the spacer layer 4 to the depth y2 of the second concave portion 33 formed on the resin stamper 10. It is formed to have a size y2 + D or less. In addition, the side surface 53 s is also formed so as to be located inside the side surface 33 s of the second recess 33 formed in the resin stamper 10.

  In the second convex portion 53, ΔD2 / D is 0.5 or less when ΔD2 is obtained by subtracting the thickness D of the spacer layer 4 from the height x2 of the second convex portion 53. It is formed at a height.

  When the substrate 2 is thus formed, the first information layer 3 is then formed on the substrate 2 by sputtering or the like, as shown in FIG. As shown in FIG. 8, the first information layer 3 is formed on the data recording area 2c of the surface of the substrate 2 where the grooves 2a and lands 2b are formed.

  When the first information layer 3 is formed, a spacer layer 4 is then formed on the first information layer 3.

  9A to 9D are process diagrams showing the manufacturing process of the spacer layer 4.

  In forming the spacer layer 4, first, the substrate 2 on which the first information layer 3 is formed is set in a spin coating apparatus, and the first information layer 3 and the substrate 2 are integrally rotated at a low speed. . Next, as shown in FIG. 9A, the ultraviolet curable resin becomes the first information from the data recording area side of the substrate 2 having a low height toward the first convex portion 52 side having a high height. It is discharged on the layer 3.

  When the ultraviolet curable resin is discharged onto the first information layer 3, the rotation of the substrate 2 is stopped, and the resin stamper 10 has the surface on which the first recess 32 and the second recess 33 are formed downward. Is set above the substrate 2. Thereafter, as shown in FIG. 9B, the resin stamper 10 is moved downward, and the distance between the first information layer 3 and the resin stamper 10 is reduced to the thickness of the spacer layer 4 to be formed by curing shrinkage. The resin stamper 10 is brought close to the substrate 2 until it becomes the same as the thickness of the thinned portion or the thinned portion by the centrifugal force generated by the rotation.

  In the present embodiment, the first recess 32 and the second recess 33 are formed on the surface of the resin stamper 10, and the first recess 32 and the second recess of the resin stamper 10 are formed on the surface of the substrate 2. Since the first convex portion 52 and the second convex portion 53 are formed at a position corresponding to 33, the first convex portion formed on the substrate 2 when the resin stamper 10 and the substrate 2 are brought closer to each other. 52 and the second convex portion 53 enter the first concave portion 32 and the second concave portion 33 formed in the resin stamper 10, respectively.

  Further, in the present embodiment, the height x1 of the first convex portion 52 formed on the substrate 2 is formed to be equal to or less than the depth y1 of the first concave portion 32 formed on the resin stamper 10. In addition, the height x2 of the second convex portion 53 formed on the substrate 2 is equal to or less than y2 + D obtained by adding the thickness D of the spacer layer 4 to the depth y2 of the second concave portion 33 formed on the resin stamper 10. Therefore, even when the resin stamper 10 is brought close to the substrate 2 until the distance between the first information layer 3 and the resin stamper 10 reaches a predetermined distance, the substrate 2 and the resin stamper 10 are also formed. Can be prevented, and the first information layer 3 and the resin stamper 10 can be sufficiently brought close to each other.

  When the resin stamper 10 is moved close to the substrate 2 to a predetermined position and positioned, the resin stamper 10 and the substrate 2 are integrally rotated at a high speed as shown in FIG. The ultraviolet curable resin discharged onto the substrate 2 is spread on the first information layer 3 toward the peripheral edge of the substrate 2 by the centrifugal force generated by the rotation.

  Thus, in the case where the ultraviolet curable resin is spread on the first information layer 3 by utilizing centrifugal force, the first convex portion 52 and the second convex portion 53 are formed at the locations. Involvement of the ultraviolet curable resin or the like occurs to easily generate bubbles in the ultraviolet curable resin, but in the present embodiment, the height of the first convex portion 52 is ΔD1 / D ≦ 0.5. The second convex portion 53 is formed so as to satisfy the condition, and the height of the second convex portion 53 is formed so as to satisfy the condition of ΔD2 / D ≦ 0.5. Since all of the portions 53 are formed so as to be lower than a predetermined height, it is possible to prevent the UV curable resin from being involved, and bubbles are generated in the UV curable resin. It is possible to prevent the occurrence.

  Further, when bubbles are generated in the ultraviolet curable resin when the ultraviolet curable resin is spread on the first information layer 3, the bubbles are particularly generated in the second convex portion 52 of the substrate 2. However, in the present embodiment, the ultraviolet curable resin is first added from the data recording area side of the substrate 2 having a low height toward the first convex portion 52 having a high height. In such a case, it is possible to effectively prevent bubbles from remaining in the stepped portion of the substrate 2.

  When the ultraviolet curable resin is spread to the peripheral edge of the substrate 2, the rotation speed of the resin stamper 10 and the substrate 2 is switched to a low speed, and as shown in FIG. Is irradiated. As a result, the ultraviolet curable resin interposed between the resin stamper 10 and the first information layer 3 is cured, and a spacer layer 4 having a thickness D is formed on the first information layer 3.

  Next, the resin stamper 10 is peeled off from the spacer layer 4, and then the substrate 2 on which the spacer layer 4 is formed is set in a sputtering apparatus. As shown in FIG. 10, the sputtering method is performed on the spacer layer 4. Thus, the second information layer 5 is formed.

  Finally, the substrate 2 on which the second information layer 5 is formed is set in a spin coating apparatus, and as shown in FIG. 11, the light transmission layer 6 is formed on the second information layer 5 by spin coating. Thus, the optical recording medium 1 is completed.

  12A and 12B are schematic cross-sectional views of a resin stamper and a substrate according to another preferred embodiment of the present invention.

  In this embodiment, the resin stamper 60 is formed with a first convex portion 62 and a second convex portion 63 on the inner side of the region 61 corresponding to the data recording region, and the substrate 70 is formed as shown in FIG. As shown, a first concave portion 72 and a second concave portion 73 are formed at positions corresponding to the first convex portion 62 and the second convex portion 63 formed on the resin stamper 60.

  In the present embodiment, the first convex portion 62 formed on the resin stamper 60 is formed such that its height y3 is equal to or less than the depth x3 of the first concave portion 72 formed on the substrate 70. The side surface 62 s is formed so as to be located inside the side surface 72 s of the first recess 72 formed in the substrate 70.

  On the other hand, the second convex portion 63 formed on the resin stamper 60 has a height y4 obtained by adding the thickness D of the spacer layer 4 to the depth x4 of the second concave portion 73 formed on the substrate 70. The side surface 63 s is formed so as to be located inside the side surface 73 s of the second recess 73 formed in the substrate 70.

  In this embodiment, the first recess 72 formed in the substrate 70 has a thickness D of the spacer layer 4 to be formed, and a thickness D of the spacer layer 4 from the depth x3 of the first recess 72. When ΔD3 is subtracted, ΔD3 / D is formed to a depth that is 0.5 or less. On the other hand, the second recess 73 formed in the substrate 70 has a depth x4 of the second recess 73. When the thickness D obtained by subtracting the thickness D of the spacer layer 4 is ΔD4, ΔD4 / D is formed to a depth of 0.5 or less. Therefore, for example, when the thickness of the spacer layer 4 is 25 μm, both the first recess 72 and the second recess 73 are formed to a depth of 37.5 μm or less.

  The spacer layer 4 is formed as follows using the resin stamper 60 and the substrate 70 having the above-described configuration.

  FIGS. 13A to 13D are process diagrams showing the formation process of the spacer layer 4.

  In forming the spacer layer 4 on the surface of the first information layer 3, first, the substrate 70 on which the first information layer 3 is formed is set in a spin coating apparatus and is shown in FIG. 13 (a). As described above, the ultraviolet curable resin is discharged onto the substrate 70 on which the first information layer 3 is formed. In discharging the ultraviolet curable resin, as shown in FIG. 13A, the ultraviolet curable resin is directed from the first concave portion 72 having a low height toward the data recording area side of the substrate 70 having a high height. Resin is discharged onto the first information layer 3.

  Next, as shown in FIG. 13B, the resin stamper 60 is placed above the substrate 70 with the surface on which the first protrusions 62 and the second protrusions 63 are formed facing downward. Set. Thereafter, the resin stamper 60 is moved downward, and the resin stamper 60 is brought close to the substrate 70 until the distance between the first information layer 3 and the resin stamper 60 becomes substantially the same as the thickness of the spacer layer 4 to be formed.

  In the present embodiment, the first convex portion 62 and the second convex portion 63 are formed on the surface of the resin stamper 60, and the first convex portion 62 and the second convex portion 63 of the resin stamper 60 are formed on the surface of the substrate 70. A first recess 72 and a second recess 73 are formed at a position corresponding to the second protrusion 63, and a height y 3 of the first protrusion 62 formed in the resin stamper 60 is formed on the substrate 70. The second concave portion formed in the substrate 70 is formed such that the height y4 of the second convex portion 63 formed in the resin stamper 60 is less than the depth x3 of the first concave portion 72 to be formed. Since the depth x4 is 73 and the thickness D of the spacer layer 4 is added to the size x4 + D or less, the distance between the first information layer 3 and the resin stamper 60 is a predetermined distance. Until the resin stamper 60 is brought close to the substrate 70 Also, it is possible to prevent the substrate 70 and the resin stamper 60 are in contact, it is possible to sufficiently close the first information layer 3 and the resin stamper 60.

  When the resin stamper 60 is moved close to the substrate 70 to a predetermined position and positioned, the resin stamper 60 and the substrate 70 are integrally rotated at a high speed as shown in FIG. The ultraviolet curable resin discharged on the top is spread on the first information layer 3.

  In this embodiment, the depth of the first recess 72 formed in the substrate 70 is formed so as to satisfy the condition of ΔD3 / D ≦ 0.5, and the depth of the second recess 73 is Since it is formed so as to satisfy the condition of ΔD4 / D ≦ 0.5, it is possible to prevent the ultraviolet curable resin from being involved, and to prevent the generation of bubbles in the ultraviolet curable resin. It becomes possible.

  Finally, the rotational speeds of the resin stamper 60 and the substrate 70 are switched, and as shown in FIG. 13D, ultraviolet rays are irradiated from the resin stamper 60 side, the ultraviolet curable resin is cured, and the spacer layer 4 is formed. It is formed.

  FIGS. 14A and 14B are schematic cross-sectional views of a resin stamper and a substrate according to another preferred embodiment of the present invention.

  In this embodiment, as shown in FIG. 14A, the resin stamper 80 has a first recess 82 and a second recess 83 formed inside the area 81 corresponding to the data recording area, and the substrate As shown in FIG. 14B, the first recess 92 and the second recess 93 are located at positions corresponding to the first recess 82 and the second recess 83 formed in the resin stamper 80, as shown in FIG. Is formed.

  In this embodiment, the first concave portion 92 formed in the substrate 90 has ΔD5 / D when ΔD5 is obtained by subtracting the thickness D of the spacer layer 4 from the depth x5 of the first concave portion 92. On the other hand, the second concave portion 93 formed on the substrate 90 is formed to a depth of 0.5 or less. On the other hand, the depth D6 of the second concave portion 93 is subtracted from the thickness D of the spacer layer 4 by ΔD6. In this case, ΔD6 / D is formed to a depth of 0.5 or less.

  In the present embodiment, the depth y5 of the first recess 82 and the depth y6 of the second recess 83 formed in the resin stamper 80 are not particularly limited, and are formed to an arbitrary depth. be able to.

  The spacer layer 4 is formed as follows using the resin stamper 80 and the substrate 90 having the above-described configuration.

  FIGS. 15A to 15D are process diagrams showing the manufacturing process of the spacer layer 4.

  In forming the spacer layer 4 on the surface of the first information layer 3, first, the substrate 90 on which the first information layer 3 is formed is set in a spin coating apparatus and is shown in FIG. As described above, the ultraviolet curable resin is discharged onto the substrate 90 on which the first information layer 3 is formed. When discharging the ultraviolet curable resin, as shown in FIG. 15A, the ultraviolet curable resin is directed from the first concave portion 92 side having a low height toward the data recording area side of the substrate 90 having a high height. Resin is discharged.

  Next, as shown in FIG. 15B, the resin stamper 80 is set above the substrate 90 with the surface on which the first concave portion 82 and the second concave portion 83 are formed facing downward. The Thereafter, the resin stamper 80 is moved downward, and the resin stamper 80 is brought close to the substrate 90 until the distance between the first information layer 3 and the resin stamper 80 becomes the same as the thickness of the spacer layer 4 to be formed.

  In the present embodiment, the first recess 82 and the second recess 83 are formed on the surface of the resin stamper 80, and the first recess 82 and the second recess 83 of the resin stamper 80 on the surface of the substrate 90 are formed. Since the first recess 92 and the second recess 93 are formed at a position corresponding to, the resin stamper 80 and the substrate until the distance between the first information layer 3 and the resin stamper 80 reaches a predetermined distance. Even when 90 is brought closer, the resin stamper 80 and the substrate 90 can be prevented from contacting each other.

  When the resin stamper 80 is brought close to the predetermined position and positioned, the resin stamper 80 and the substrate 90 are integrally rotated at a high speed as shown in FIG. The ultraviolet curable resin discharged on the top is spread on the first information layer 3.

  Finally, the rotation speed of the resin stamper 80 and the substrate 90 is switched to a low speed, and as shown in FIG. 15D, ultraviolet rays are irradiated from the resin stamper 80 side, the ultraviolet curable resin is cured, and the spacer layer 4 is formed.

  The present invention is not limited to the above embodiments and examples, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is a thing.

  For example, in the embodiment shown in FIGS. 1 to 15, an ultraviolet curable resin is discharged onto the substrate 2, 70, 90 on which the first information layer 3 is formed, and thereafter, this ultraviolet curable resin is discharged. The resin stampers 10, 60, 80 are covered from above the resin. Instead, an ultraviolet curable resin is discharged onto the resin stampers 10, 60, 80, and then the ultraviolet curable resin is discharged. The substrate 2 on which the first information layer 3 is formed may be covered over the resin. In such a case, the depth y1 of the first convex portion 32 and the depth y2 of the second convex portion 33 of the resin stamper 10 or the depth y3 and the second concave portion of the first concave portion 62 of the resin stamper 60 are used. 63, or the depth y5 of the first recess 82 and the depth y6 of the second recess 83 of the resin stamper 80 subtract the thickness D of the spacer layer 4 from the depth or height y1 to y6. When this is taken as ΔD, it is formed so as to satisfy the condition of ΔD / D ≦ 0.5.

  In the embodiment shown in FIGS. 1 to 11, the structure of the molds 20 and 40 is changed to obtain the substrate 2 and the resin stamper 10 having a predetermined shape. In addition, the resin stamper 10 does not necessarily have to have a predetermined shape by changing the structure of the mold, and after injection molding, a part of the substrate and the resin stamper is removed. By processing, a substrate having a predetermined shape and a resin stamper may be obtained, or by using both the change of the mold structure and the processing after injection molding, A resin stamper may be obtained. The same applies to the substrates 70 and 90 and the resin stampers 60 and 80 shown in FIGS.

  Further, in the embodiment shown in FIG. 1 to FIG. 15, the spacer layer 4 covers the resin stamper on the resin on the substrate after discharging the ultraviolet curable resin in the vicinity of the central portion of the substrate 2. However, it is not always necessary to rotate the substrate after applying the resin stamper. Before applying the resin stamper, the substrate is rotated so that the resin layer is formed on the substrate. The spacer layer 4 may be formed by forming and then covering with a resin stamper.

  In the embodiment shown in FIGS. 1 to 15, the spacer layer 4 is formed of an ultraviolet curable resin, but it is not always necessary to form the spacer layer 4 with an ultraviolet curable resin. The spacer layer 4 may be formed of another radiation curable resin such as a linear curable resin.

  Further, in the embodiment shown in FIGS. 1 to 15, the optical recording medium 1 is a write-once type or rewritable type in which a write-once type or phase change type information layer 3 is formed on a substrate 2, 70, 90. However, the optical recording medium according to the present invention is not limited to the write-once or rewritable optical recording medium, and pits are formed on the surface of the substrate 2 and A read-only ROM type optical recording medium in which a reflective layer is formed and an information layer is constituted by the pits and the reflective layer may be used.

  Further, in the embodiment shown in FIG. 1 to FIG. 15, the optical recording medium 1 includes two information layers including a first information layer 3 and a second information layer 5. The invention is not limited to an optical recording medium having two information layers, but can also be applied to an optical recording medium having three or more information layers.

FIG. 1 is a schematic perspective view of an optical recording medium according to a preferred embodiment of the present invention. FIG. 2 is a schematic enlarged cross-sectional view of a portion indicated by A in FIG. FIG. 3 is a schematic cross-sectional view showing a schematic configuration of a mold for forming a resin stamper. FIG. 4 is a schematic cross-sectional view of a resin stamper. FIG. 5 is a schematic cross-sectional view showing a schematic configuration of a mold for forming a substrate. FIG. 6 is a schematic cross-sectional view of the substrate. FIG. 7 is a schematic enlarged cross-sectional view showing the first concave portion and the second concave portion formed in the resin stamper, and the first convex portion and the second convex portion formed in the substrate. FIG. 8 is a process diagram showing the manufacturing process of the first information layer. FIG. 9 is a process diagram showing a manufacturing process of the spacer layer. FIG. 10 is a process diagram showing a manufacturing process of the second information layer. FIG. 11 is a process diagram showing a manufacturing process of the light transmission layer. FIG. 12 is a schematic cross-sectional view of a resin stamper and a substrate according to another preferred embodiment of the present invention. FIG. 13 is a process diagram showing a manufacturing process of a spacer layer according to another preferred embodiment of the present invention. FIG. 14 is a schematic cross-sectional view of a resin stamper and a substrate according to another preferred embodiment of the present invention. FIG. 15 is a process diagram showing a manufacturing process of a spacer layer according to another preferred embodiment of the present invention. FIG. 16 is a schematic cross-sectional view showing a schematic configuration of a conventional mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical recording medium 2 Board | substrate 2a Groove 2b Land 3 1st information layer 4 Spacer layer 5 2nd information layer 6 Light transmission layer 7 Center hole 10 Resin stamper 11 Metal stamper 20 Mold 21 Fixed type 22 Movable type 23 Sprue bush 24 inner peripheral holder 25 mirror block 26 outer peripheral holder 27 intake pipe 28a first convex step 28b second convex step 29 cut punch 30 mirror surface block 31 region corresponding to data recording region 32 first concave portion 33 second concave portion 40 Mold 41 Fixed mold 42 Movable mold 43 Sprue bush 44 Inner peripheral holder 45 Mirror surface block 46 Outer peripheral holder 47 Intake pipe 48a First concave step 48b Second concave step 49 Cut punch 50 Mirror surface block 52 First convex portion 53 First Second convex part 60 Resin stamper 62 First convex part 63 No. Second convex part 70 Substrate 72 First concave part 73 Second concave part 80 Resin stamper 82 First concave part 83 Second concave part 90 Substrate 92 First concave part 93 Second concave part 100 Mold 101 Fixed mold 102 Movable type DESCRIPTION OF SYMBOLS 103 Sprue bush 104 Metal stamper 105 Inner peripheral holder 106 Mirror surface block 107 Outer periphery holder 108 Cut punch 109 Mirror surface block 110 Substrate

Claims (6)

A convex portion is formed inside the data recording area, and a resin stamper in which a concave portion is formed at a position corresponding to the convex portion of the substrate is opposed to the substrate on which the information layer is formed in the data recording area, Sandwiching a radiation curable resin between the substrate and the resin stamper;
Irradiating radiation, curing the radiation curable resin between the resin stamper and the substrate, and forming a spacer layer,
When the thickness of the spacer layer is D and the depth of the concave portion formed in the resin stamper is y, the height x of the convex portion of the substrate is formed so as to satisfy the condition of x ≦ y + D. A method of manufacturing an optical recording medium. A concave portion is formed inside the data recording area, and a resin stamper having a convex portion formed at a position corresponding to the concave portion of the substrate is opposed to the substrate on which the information layer is formed in the data recording area, Sandwiching a radiation curable resin between the substrate and the resin stamper;
Irradiating radiation, curing the radiation curable resin between the resin stamper and the substrate, and forming a spacer layer,
The height y of the convex portion of the resin stamper is formed so as to satisfy the condition of y ≦ x + D, where D is the thickness of the spacer layer and x is the depth of the concave portion of the substrate. An optical recording medium manufacturing method. A substrate in which a recess is formed inside the data recording area and an information layer is formed in the data recording area is opposed to a resin stamper in which a recess is formed at a position corresponding to the recess of the substrate. And a step of sandwiching a radiation curable resin by the resin stamper,
And a step of curing the radiation curable resin between the resin stamper and the substrate to form a spacer layer. And a step of discharging the radiation curable resin onto the substrate on which the information layer is formed,
The height of the convex portion of the substrate or the depth x of the concave portion is formed so as to satisfy the condition of ΔD / D ≦ 0.5 when ΔD is obtained by subtracting the thickness D of the spacer layer from x. 4. The method of manufacturing an optical recording medium according to claim 1, wherein the optical recording medium is manufactured. Furthermore, the method includes a step of discharging the radiation curable resin onto the resin stamper,
The depth of the concave portion or the height y of the convex portion of the resin stamper satisfies the condition of ΔD / D ≦ 0.5 when ΔD is obtained by subtracting the thickness D of the spacer layer from y. 4. The method for producing an optical recording medium according to claim 1, wherein the optical recording medium is formed. 6. The optical recording medium according to claim 4, wherein the radiation curable resin is discharged from a low position of the substrate on which the information layer is formed or a position of the resin stamper to a high position. Manufacturing method.

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