JP2010097649A - Apparatus and method of manufacturing optical recording medium - Google Patents

Abstract

An object of the present invention is to provide an optical recording medium manufacturing apparatus and a manufacturing method capable of manufacturing an optical recording medium having a high optical flatness even with a thick recording layer.
A manufacturing apparatus includes a pair of holding members 21 that hold an outer surface 11f of a substrate 11 in close contact with a contact surface (bottom surface C1), and a pair of holding members 21 so that the pair of holding members 21 come close to each other. A force applying unit that applies force, and an injection device that injects the photosensitive solution into a space formed by each substrate 11 and the spacer 13 are provided. Then, until the photosensitive solution in the space is cured to form the recording layer 12, the adhesion force between the substrate 11 and the contact surface of the holding member 21 and the force applied to the holding member 21 by the force applying means are maintained. And the contact surface of the holding member 21 protrudes in the direction in which the central portion C11 protrudes toward the substrate 11 and the portion (annular portion C12) corresponding to the peripheral portion 12a of the recording layer 12 is away from the substrate 11. It is curved and formed so as to be recessed.
[Selection] Figure 4

Description

  The present invention relates to an optical recording medium manufacturing apparatus and manufacturing method in which data is recorded in a volume on a recording layer using light.

  In recent years, an optical recording medium having a thick recording layer that records a large volume of data as interference fringes by using interference of light has been developed. The optical recording medium generally includes a pair of substrates and a recording layer formed between these substrates (hereinafter also referred to as “spacerless type”) or a ring shape. A recording layer, a spacer that surrounds the outer peripheral surface and the inner peripheral surface of the recording layer, and a pair of substrates that sandwich the recording layer and the spacer (hereinafter, also referred to as “type with spacer”) are known. .

  By the way, an optical recording medium that records information in volume is sensitive to the wavefront and phase of light in principle, and therefore requires flatness (optical flatness) on the surface of the recording layer. In order to satisfy such requirements, conventionally, there are methods disclosed in Patent Documents 1 and 2 as methods for producing a recording medium without spacers, and a method for producing a recording medium with spacers. There is a method disclosed in Document 3.

  Specifically, in the manufacturing methods disclosed in Patent Document 1 and Patent Document 2, a pair of substrates is held in parallel by a pair of holders that vacuum-suck each substrate, and a photosensitive solution (after curing) is held in the gap. An optical recording medium is manufactured by injecting a liquid to be a recording layer. Further, in the manufacturing method disclosed in Patent Document 3, a pair of substrates is bonded in advance through a spacer, and a photosensitive solution is injected from a notch formed in an outer spacer, thereby manufacturing an optical recording medium. Yes.

Japanese translation of PCT publication No. 2004-523057 Special table 2005-500581 gazette JP 2001-5368 A

  However, in the technique of Patent Document 3, when the recording layer in the space surrounded by the pair of substrates and the spacers shrinks inward along the surface of the substrate due to curing, the central portion of the recording layer (which is sandwiched between the two spacers). There is a problem that the central portion of the recording layer swells outward in the direction perpendicular to the surface of the substrate. Further, in such a recording medium with a spacer, since the spacer and the peripheral surface of the recording layer are in close contact with each other, the movement of the peripheral surface of the recording layer is constrained by the spacer. There is also a problem that both the lower surface (contact surface with the substrate) is recessed inward.

  Further, in the techniques of Patent Documents 1 and 2, even if the recording layer is about to shrink inward along the surface of the substrate between the pair of substrates due to curing, each substrate is held by the holder so that the central portion of the recording layer is Is suppressed from expanding in the thickness direction, so that both surfaces of the recording layer (surface on the substrate side) are kept flat while being held by the holder. However, when stress is generated in the form of heat or curing shrinkage when the recording layer is formed, removing the recording medium from the holder releases the force that the recording layer tends to shrink, and the recording layer is placed on the surface of the substrate. There is a problem that the central portion of the recording layer swells in the thickness direction.

  Accordingly, an object of the present invention is to provide an optical recording medium manufacturing apparatus and a manufacturing method capable of manufacturing an optical recording medium having a high optical flatness even with a thick recording layer.

  The present invention for solving the above-described problems is an optical recording medium manufacturing apparatus comprising: a recording layer on which information is recorded in volume by a laser beam; and a pair of substrates sandwiching the recording layer. A pair of holding members having a contact surface that is in close contact with the outer surface of the substrate in a state where the substrate is held in a state where the substrate is held, and the recording layer is interposed between the substrates. An injecting device for injecting a photosensitive solution to be formed, and the adhesion between the substrate and the contact surface of the holding member is maintained until the photosensitive solution between the substrates is cured to form the recording layer. The contact surface is curved and formed so that a central portion of the contact surface of the holding member protrudes toward the substrate.

  The following method may be adopted as a method for manufacturing an optical recording medium using a manufacturing apparatus corresponding to such an optical recording medium without spacers. That is, the manufacturing method according to the present invention is a method for manufacturing an optical recording medium comprising a recording layer on which information is recorded in volume by a laser beam, and a pair of substrates sandwiching the recording layer. A holding step of holding the outer surface of each substrate in close contact with each contact surface while leaving a gap between each substrate by a pair of holding members having a contact surface curved so as to protrude toward the substrate And an injecting step for injecting a photosensitive solution for forming the recording layer between the substrates, and a curing step for curing the photosensitive solution, and the holding until the injecting step and the curing step are completed. The process is continued.

  According to the present invention, the contact surface is curved so that the central portion of the contact surface of the holding member protrudes toward the substrate. Therefore, the substrate is held between the substrates while the substrates are held by the pair of holding members. The recording layer cured in step (b) is formed such that the central portion is recessed in the thickness direction following the shape of the curved contact surface. During curing, the recording layer tends to shrink along the surface of the substrate, but each substrate is held by a pair of holding members, and deformation in the thickness direction of the recording layer is suppressed, so that the surface of the substrate is The shrinkage force in the direction along is suppressed.

  Then, after the recording layer is cured, when the optical recording medium is removed from the pair of holding members, the contraction force (force that the recording layer tends to contract) suppressed by the pair of holding members is released, and the recording layer The central portion of the recording layer which is contracted along the substrate expands in the thickness direction. As a result, if the shape of the contact surface is determined so that the recessed central portion is deformed until it has the same thickness as the other portions, the surface of the recording layer is flattened after the optical recording medium is removed from the holding member. be able to. As described above, the surface of the optical recording medium without a spacer can be satisfactorily flattened.

  Further, the present invention provides a recording layer in which information is recorded in volume by a laser beam, a pair of substrates sandwiching the recording layer, and a peripheral surface of the recording layer sandwiched between the pair of substrates. And a pair of holding members that hold the outer surface of the substrate in close contact with the contact surface, and each of the substrates sandwiching the spacer between the pair of holding members. The recording layer is formed in a space formed by the force applying means for applying a force to the holding member so that the pair of holding members come close to each other and each substrate and the spacer in a state of being sandwiched between the holding members. An injecting device that injects a photosensitive solution, and holds the contact force between the substrate and the contact surface of the holding member by the force applying unit until the photosensitive solution in the space is cured to form the recording layer. The force applied to the member is maintained And the contact surface of the holding member is curved so that a central portion protrudes toward the substrate and a portion corresponding to a peripheral portion of the recording layer is recessed in a direction away from the substrate. It is characterized by being formed.

  The following method may be adopted as a method for manufacturing an optical recording medium using a manufacturing apparatus corresponding to such an optical recording medium with a spacer. That is, the manufacturing method according to the present invention includes a recording layer in which information is recorded in volume by a laser beam, a pair of substrates sandwiching the recording layer, a pair of substrates, and a periphery of the recording layer. And a spacer disposed so as to cover the surface, wherein a central portion protrudes toward the substrate, and a portion corresponding to a peripheral portion of the recording layer is formed from the substrate. A holding step of holding the outer surface of each substrate in close contact with each contact surface by a pair of holding members having contact surfaces curved so as to be recessed in a direction away from each other, and holding the pair of substrates sandwiching each spacer A photosensitive solution for forming the recording layer in a space formed by each substrate and the spacer, and a force applying step for applying a force to the holding member so that the pair of holding members approach each other in a state of being sandwiched between the members Inject And entering step, the provided photosensitive solution and curing step of curing, the until said injection step and the curing step is completed, characterized in that to continue the holding step and the force applying step.

  According to this, the central portion of the contact surface of the holding member protrudes toward the substrate, and the portion corresponding to the peripheral portion of the recording layer is recessed in the direction away from the substrate, so that it is held by the pair of holding members. The recording layer cured between each substrate and the spacer is formed such that the central portion is recessed in the thickness direction and the peripheral edge is expanded in the thickness direction following the shape of the curved contact surface. During curing, the recording layer tends to shrink along the surface of the substrate, but each substrate is held by a pair of holding members, and deformation in the thickness direction of the recording layer is suppressed, so that the surface of the substrate is The shrinkage force in the direction along is suppressed. Then, when the optical recording medium is removed from the pair of holding members after the recording layer is cured, the contraction force (the force that the recording layer attempts to contract) suppressed by the pair of holding members is released.

  Along with this, the recording layer contracts along the substrate, so that the concave central portion of the recording layer swells in the thickness direction. At this time, since the end surface (peripheral surface) of the peripheral portion of the recording layer is in close contact with the spacer, the inward movement of the end surface is constrained by the spacer, so that the contact surface of each peripheral portion with each substrate is thick. Shrink in the vertical direction. For this reason, if the shape of the contact surface is determined so that the recessed central portion and the bulged peripheral edge portion are deformed to the same thickness, the surface of the recording layer is flattened after the optical recording medium is removed from the holding member. Can be a surface. As described above, the surface of the optical recording medium with a spacer can be satisfactorily flattened.

  As the optical recording medium, for example, a holographic recording medium in which the recording layer is a recording layer on which a volume hologram is recorded using interference fringes due to interference of a plurality of laser beams can be employed.

  In the present invention, a vacuum suction device for bringing the substrate into close contact with the contact surface by vacuum suction may be connected to the pair of holding members.

  According to this, since the substrate can be securely adhered to the curved contact surface of the holding member by vacuum suction, the surface of the recording layer can be shaped to follow the contact surface, and after being removed from the holding member It is possible to more surely realize the flattening of the surface of the recording layer utilizing the shrinkage of the recording layer.

  The thickness of the recording layer of the optical recording medium manufactured by the manufacturing apparatus or manufacturing method according to the present invention is preferably 200 μm or more. When the thickness is 200 μm or more, expansion / contraction (deformation) after curing appears remarkably, so that the present invention can be used effectively.

  According to the present invention, since the contact surface of the holding member is curved so as to correspond to the surface shape of the recording layer deformed by the shrinkage of the recording layer after being removed from the holding member, the recording layer after being removed from the holding member The surface of the recording layer can be flattened by utilizing the deformation in the thickness direction, and an optical recording medium having high optical flatness can be manufactured.

[First Embodiment]
Next, with respect to the first embodiment of the present invention, an optical recording medium (hereinafter, referred to as a recording layer in which a volume hologram is recorded using interference fringes due to interference of a plurality of laser beams) A holographic recording medium) will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is an exploded perspective view showing a holographic recording medium manufactured by the manufacturing apparatus according to the first embodiment.

  First, the structure of the holographic recording medium 1 will be described with reference to FIG. The holographic recording medium 1 includes a pair of substrates 11, a recording layer 12 sandwiched between the substrates 11, and a spacer 13 disposed so as to cover the peripheral surface of the recording layer 12.

  The substrate 11 is a layer that protects the upper and lower surfaces of the recording layer 12, and is formed into a rectangular flat plate with a material that transmits laser light having a wavelength of about 532 nm, for example. Here, “laser light” refers to laser light used for any one of information light, reference light, and readout light.

  The material of the substrate 11 may be sufficiently transparent in the wavelength region of light to be used. For example, glass, ceramics, resin, and the like are used. Resin is particularly preferable from the viewpoint of moldability and cost. is there. Examples of the resin include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, polycycloolefin resin, silicone resin, ABS resin, and urethane resin. . Among these, polycarbonate resin, acrylic resin, and polycycloolefin resin are particularly preferable in terms of moldability, optical characteristics, and cost.

  In addition, the substrate 11 can be subjected to various processing and processing for providing functions. For example, reflective film, selective reflection film, antireflection film, vapor deposition film for improving adhesion, vapor deposition film for improving barrier properties, gap layer, information layer with servo signal for focusing servo and tracking servo, selective absorption It is possible to provide a layer and a permselective layer. The gap layer here is provided in order to keep a distance between the functional layer and the substrate interface particularly when at least one of the substrates 11 includes the above-described functional layer inside the substrate. It refers to the transparent layer.

  In addition, as a molding method, for example, injection molding or the like can be employed. Furthermore, the thickness of the substrate 11 is preferably 0.1 to 5 mm, and more preferably 0.3 to 2 mm. This is because if the thickness of the substrate 11 is less than 0.1 mm, distortion of the shape during storage of the recording medium cannot be suppressed, and if it exceeds 5 mm, the weight of the entire recording medium increases.

  The recording layer 12 records data as interference fringes by reacting with irradiation of a plurality of laser beams (specifically, interference between information light and reference light). The recording layer 12 is formed by injecting a later-described photosensitive liquid L into a space formed between the pair of substrates 11 and the spacers 13.

  The material of the recording layer 12 is not particularly limited and may be appropriately selected depending on the purpose. For example, (1) a photopolymer that undergoes a polymerization reaction upon irradiation with light and becomes a polymer, (2) photo Photorefractive material exhibiting a refractive effect (a space charge distribution is generated by light irradiation and the refractive index is modulated), (3) a photochromic material in which molecular isomerization is caused by light irradiation and a refractive index is modulated, and (4) lithium niobate And inorganic materials such as barium titanate, (5) chalcogen materials, and the like.

  The thickness of the recording layer 12 is not particularly limited and may be appropriately selected depending on the purpose. The thickness is preferably 1 to 1000 μm, and more preferably 200 to 700 μm. When the recording layer 12 is 200 μm or more, since the shrinkage force at the time of curing is large, the present invention can be effectively used. From this viewpoint, the present invention is particularly effective when the recording layer is thicker than 400 μm.

  The photosensitive liquid L that forms the recording layer 12 is a photosensitive compound capable of forming a hologram in response to exposure for recording, and can be cured in response to light, heat, pressure, etc. while dissolving the compound. It is obtained by mixing a binder precursor or a melt moldable binder. Here, the photosensitive compounds are those exemplified in (1) to (5) above. Examples of the binder precursor include a polymer precursor composed of a radical generator and a radical polymerizable monomer such as acrylate, a polymer precursor composed of a cation generator or a latent catalyst and an epoxy compound, a silicone resin precursor, and a silanol. Examples include a sol-gel material composed of a compound and a catalyst, a polyester elastomer precursor, a polyether rubber precursor, a polyurethane elastomer precursor, and the like. Examples of the fusible binder include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, polycycloolefin resin, silicone resin, ABS resin, urethane resin, ethylene- ( Examples thereof include a salt-crosslinked product of a (meth) acrylic acid copolymer and an ethylene- (meth) acrylic acid copolymer (sometimes referred to as an ionomer). From the viewpoint of sensitivity, a photopolymer material made of an organic compound, a photorefractive material made of an organic compound, and a photochromic material made of an organic compound are preferably used as the photosensitive compound. As the binder precursor or binder, from the viewpoint of moldability and compatibility with the photosensitive compound, a polymer precursor utilizing radical polymerization or cationic polymerization, a polyester elastomer precursor, a polyether rubber precursor, a polyurethane elastomer precursor. The body is preferably used. In particular, a combination of a photopolymer material made of an organic compound and a polyester elastomer precursor or a polyurethane elastomer precursor is most preferable.

  The combination of the photosensitive compound and the binder precursor or binder is arbitrary, and two or more kinds may be mixed. In addition to these, various additives such as filler particles, antioxidants, UV absorbers, plasticizers, and lubricants may be appropriately added depending on the purpose. Specific examples of materials that can be used in the present invention include, for example, JP-A No. 11-352303, JP-A No. 2004-537620, JP-A No. 2005-502918, JP-A No. 2003-53469, and JP-A No. 2004-2004. No. 287138, JP-A No. 2004-354586, JP-A No. 2005-3790, JP-A No. 2005-43862, JP-A No. 2005-140852, JP-A No. 2005-275389, JP-A No. 2006-79049 The material described in the gazette etc., or a material similar to it is mentioned as a suitable example.

  The spacer 13 is formed in a rectangular frame shape along the outer peripheral edge of the substrate 11, and an opening 13 a is formed in the corner portion by cutting out one corner portion. The upper and lower surfaces of the spacer 13 are accurately formed so as to be parallel to each other, and are bonded to each substrate 11 by an adhesive.

  In addition, as the material of the spacer 13, the materials that can be used as the material of the substrate 11 described above, that is, glass, ceramics, resin, and the like can be used. However, the resin is particularly preferable in terms of moldability and cost. . Examples of the resin include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, polycycloolefin resin, silicone resin, ABS resin, and urethane resin. . Unlike the case where it is used as the substrate 11, the spacer 13 may be transparent, or may have coloring or light blocking properties. In particular, acrylic resin, epoxy resin, polycycloolefin resin, and polyurethane resin are preferable in terms of strength.

  Next, the manufacturing apparatus 2 that manufactures the above-described holographic recording medium 1 will be described. In the drawings to be referred to, FIG. 2 is a schematic front view showing a manufacturing apparatus for manufacturing a holographic recording medium, and FIG. 3 is a perspective view showing details of a holding member. FIG. 4 is a sectional view showing the shape of the bottom surface of the holding member in comparison with the completed holographic recording medium. 4 and the like, the curved shape of the bottom surface C1 of the holding member 21 is exaggerated for convenience.

  As shown in FIG. 2, the manufacturing apparatus 2 mainly includes a pair of holding members 21, a pressing device 22 as an example of a force applying unit, an injection device 23, a base 24, and a vacuum suction device 25. It is configured.

  The pair of holding members 21 are each formed in a plate shape, and one of the holding members 21A is fixed to the pedestal 24, and the other holding member 21B moves forward and backward with respect to the one holding member 21A. It is supported by the pressing device 22. Specifically, as shown in FIG. 3, each holding member 21 includes opposing surfaces 21b that face each other.

  A concave portion 21c for positioning the substrate 11 (see FIG. 1) of the holographic recording medium 1 is formed in a substantially central portion of the facing surface 21b. Here, the bottom surface C1 of the recess 21c is a contact surface that comes into contact with the outer surface 11f of the substrate 11 (the surface opposite to the recording layer 12).

  Specifically, the central portion C11 (portion surrounded by a thick broken line) of the bottom surface C1 is formed in a curved shape protruding toward the substrate 11 to be installed, as shown in FIG. In addition, an annular portion C12 (a portion surrounded by a thin broken line and a thick broken line in FIG. 3) corresponding to the peripheral edge 12a of the recording layer 12 in the bottom surface C1 is formed in a curved shape that is recessed in a direction away from the substrate 11. Yes. Here, the amount of protrusion and curvature of the central portion C11 and the amount of depression and curvature of the annular portion C12 are estimated by changes due to contraction of the recording layer 12 when the holographic recording medium 1 is removed from the holding member 21 through experiments, simulations, or the like. Thus, it is appropriately set according to the material.

  The bottom surface C <b> 1 has an annular flat surface C <b> 13 corresponding to the spacer 13 in addition to a portion formed by being curved at the center portion C <b> 11 and the annular portion C <b> 12. Thereby, since the peripheral part of each board | substrate 11 can be pressed on the flat upper and lower surfaces of the spacer 13 by the flat surface C13, the peripheral part of each board | substrate 11 can be favorably joined to the upper and lower surfaces of the spacer 13 with an adhesive agent. It is possible.

  Furthermore, a groove 21d for vacuum suction of the substrate 11 is formed on the bottom surface C1 of the recess 21c so as to extend over substantially the entire bottom surface C1 of the recess 21c (see FIG. 3). The groove 21 d communicates with a tube connection port 21 f formed on the side surface of the holding member 21 via a passage 21 e formed inside the holding member 21. Accordingly, as shown in FIG. 2, the tube connection port 21 f of the holding member 21 and the vacuum suction device 25 are connected by the tube T, and then the vacuum suction device 25 is operated, whereby the concave portion 21 c of the holding member 21 is curved. The outer surface 11f of the substrate 11 is held in close contact with the bottom surface C1.

  The pressing device 22 includes a plurality of support shafts 22A that support the holding member 21B on the right side of the drawing, and a drive device 22B that advances and retracts the support shaft 22A in the axial direction by hydraulic pressure, mechanical power, or the like. Then, in a state where the pair of substrates 11 and the spacer 13 are sandwiched between the pair of holding members 21, the support shaft 22A is advanced by the driving device 22B of the pressing device 22 so that the pair of holding members 21 come close to each other. A force is applied to the right holding member 21B.

  The injection device 23 includes an ejection head 23A that ejects the photosensitive liquid L, and an apparatus body 23B that supplies the photosensitive liquid L to the ejection head 23A and moves the ejection head 23A up and down.

  Next, a method for manufacturing the holographic recording medium 1 using the manufacturing apparatus 2 described above will be described. In the drawings to be referred to, FIG. 5 is a cross-sectional view showing a process of holding the temporary assembly case, and FIG. 6 is an explanatory view showing a process of injecting a photosensitive solution into the temporary assembly case. FIG. 7 is a cross-sectional view showing the process of curing the photosensitive solution. FIG. 8 is a cross-sectional view (a) showing the state immediately after the holographic recording medium is removed from the holding member, and the recording layer due to the shrinkage of the recording layer. It is sectional drawing (b) which shows the state by which the surface of became flat. In addition, the following manufacturing methods are performed when the manufacturing apparatus 2 mentioned above operate | moves suitably by the control apparatus or operator which is not shown in figure.

  First, as shown in FIG. 1, after applying an adhesive between each substrate 11 and the spacer 13, the spacer 13 is sandwiched between the pair of substrates 11 to form a hollow temporary assembly case 1 ′ (FIG. 2). Reference). And after setting this hollow temporary assembly case 1 'in the recessed part 21c of one holding member 21A so that the opening 13a may face upwards, the vacuum suction device 25 is operated and one holding member 21A is used. Temporary assembly case 1 'is held.

  At this time, the vacuum suction by the other holding member 21B is stopped, and after the other holding member 21B is brought into contact with the temporary assembly case 1 ′ held by one holding member 21A as described later, the vacuum is applied. It is desirable to start aspiration. This is because when the other holding member 21B is brought close to the temporary assembly case 1 ′, the substrate 11 temporarily assembled as the temporary assembly case 1 ′ may be peeled off by vacuum suction by the holding member 21B. .

  After holding the temporary assembly case 1 ′ with one holding member 21 </ b> A, the pressing device 22 is actuated to bring the other holding member 21 </ b> B closer to the temporary assembly case 1 ′, and temporarily between the pair of holding members 21. The assembly case 1 'is clamped with a constant force. At this time, if vacuum suction by the other holding member 21B is not performed, vacuum suction by the other holding member 21B is started after the other holding member 21B comes into contact with the temporary assembly case 1 '. Then, by starting the vacuum suction by the other holding member 21B in this way, as shown in FIG. 5, the outer surface 11f of each substrate 11 comes into close contact with each bottom surface C1 of the pair of holding members 21, and a pair of The holding of the temporary assembly case 1 ′ by the holding member 21 is completed (holding process). After that, as shown in FIG. 2, each substrate 11 is pressed against the spacer 13 with a constant force by bringing the pair of holding members 21 close to each other with a predetermined distance by the pressing device 22 (force applying step). .

  Thereafter, the ejection head 23A of the injection device 23 is lowered, and the tip nozzle 23C is inserted into the interior of the temporary assembly case 1 ′ through the opening 13a as shown in FIG. 13 is injected into the space formed by (injection step). Then, after injecting the photosensitive solution L to the vicinity of the opening 13a, the photosensitive solution L in the temporary assembly case 1 'is cured (curing step). In this curing step, curing may be accelerated by applying heat to the photosensitive solution L.

  Then, the above-described holding step and force applying step are maintained until the above-described injection step and curing step are completed. That is, as shown in FIG. 7, the adhesive force Ft between the substrate 11 and the holding member 21 by vacuum suction and the force Fp applied to the holding member 21 by the pressing device 22 until the photosensitive solution L is cured to become the recording layer 12. And maintain.

  Thereby, the recording layer 12 cured between each substrate 11 held by the pair of holding members 21 and the spacer 13 has a central portion 12b in the thickness direction following the shape of the curved substrate 11 (bottom surface C1). While being recessed, the peripheral edge portion 12a is formed to swell in the thickness direction. Although the recording layer 12 tends to shrink toward the center during curing, both the substrate 11 and the recording layer 12 are not deformed by holding each substrate 11 by the pair of holding members 21. However, a contraction force Fc (see FIG. 8) is generated inside the recording layer 12 instead of being deformed.

  When the holographic recording medium 1 is removed from the pair of holding members 21 after the recording layer 12 is cured, as shown in FIG. 8A, the shrinkage force Fc (recording layer) suppressed by the pair of holding members 21 is obtained. Is released). As a result, the recording layer 12 contracts along the substrate 11 and collects in the central portion 12b, whereby the concave central portion 12b of the recording layer 12 expands in the thickness direction. At this time, since the end surface 12c of the peripheral edge portion 12a of the recording layer 12 is in close contact with the spacer 13, the inward movement of the end surface 12c is restrained by the spacer 13, so that the upper and lower surfaces of the peripheral edge portion 12a are both Shrink in the thickness direction. As a result, as shown in FIG. 8B, the center portion 12b that has been recessed and the peripheral portion 12a that has bulged are deformed until they have the same thickness, and the surface of the recording layer 12 becomes a flat surface.

According to the above, the following effects can be obtained in the first embodiment.
Since the bottom surface C1 of the holding member 21 is curved so as to correspond to the surface shape of the recording layer 12 that is deformed by contraction of the recording layer 12 after being removed from the holding member 21, the recording layer 12 after being removed from the holding member 21 is curved. The surface of the recording layer 12 can be flattened using the deformation in the thickness direction, and the holographic recording medium 1 having high optical flatness can be manufactured.

  Since the substrate 11 can be securely brought into close contact with the curved bottom surface C1 of the holding member 21 by vacuum suction, the surface of the recording layer 12 can be shaped to follow the bottom surface C1, and after being removed from the holding member 21 The flattening of the surface of the recording layer 12 utilizing the shrinkage of the recording layer 12 can be realized more reliably.

  Since an adhesive layer formed of an adhesive can be provided between the spacer 13 and the substrate 11, the strength of the holographic recording medium 1 can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In addition, this embodiment is a manufacturing apparatus for manufacturing a holographic recording medium without a spacer, and is a modification of the structure of the holding member according to the first embodiment described above. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the drawings to be referred to, FIG. 9 is a sectional view showing a holding member according to the second embodiment.

  As shown in FIG. 9, the holding member 21 ′ according to the second embodiment has a curved surface in which the central portion C <b> 21 of the bottom surface C <b> 2 of the recess 21 c ′ for positioning the substrate 11 protrudes toward the substrate 11 to be installed. It is formed in a shape. Further, unlike the first embodiment, the peripheral edge portion C22 of the bottom surface C2 is formed substantially flat without being recessed. In addition, the protrusion amount and curvature of the central portion C21 are appropriately set according to the material by experiments, simulations, and the like, as in the first embodiment.

  Next, a method for manufacturing the holographic recording medium 3 using the holding member 21 ′ according to the second embodiment will be described. In the drawings to be referred to, FIG. 10 is a cross-sectional view showing a step of holding a substrate with a holding member, and FIG. 11 is a cross-sectional view showing a step of curing a photosensitive solution injected between the substrates. FIG. 12 is a cross-sectional view (a) showing a state immediately after the holographic recording medium is removed from the holding member, and a cross-sectional view (b) showing a state where the surface of the recording layer is flattened by contraction of the recording layer. It is.

  As shown in FIG. 10, first, after setting each board | substrate 11 in the recessed part 21c 'of each holding member 21', while operating the vacuum suction device 25, the position of each holding member 21 'is predetermined with the press apparatus 22 Keep in position. As a result, the outer surface 11f of each substrate 11 is in close contact with the bottom surface C2 of each holding member 21 ′, and each substrate 11 is held by each holding member 21 ′ with a predetermined gap between the substrates 11. (Holding step).

  After that, as in the first embodiment, the photosensitive solution L is injected between the substrates 11 by the injection device 23 (injection step). Here, in the second embodiment, the photosensitive solution L having a certain degree of viscosity is used, and thus the photosensitive solution L is held between the substrates 11.

  And after inject | pouring the photosensitive solution L between each board | substrate 11, the photosensitive solution L is hardened (hardening process). And the holding | maintenance process mentioned above is maintained until the injection | pouring process and hardening process which were mentioned above are completed. That is, as shown in FIG. 11, the adhesion force Ft between the substrate 11 and the holding member 21 ′ by vacuum suction is maintained until the photosensitive solution L is cured to become the recording layer 12.

  Thereby, the recording layer 12 cured between the substrates 11 held by the pair of holding members 21 ′ is formed such that the central portion 12b is recessed in the thickness direction following the shape of the curved substrate 11 (bottom surface C2). Is done. During the curing, the recording layer 12 tends to shrink toward the center, but the substrate 11 and the recording layer 12 are not deformed by holding each substrate 11 by the pair of holding members 21 ′. However, a contraction force Fc (see FIG. 12) is generated inside the recording layer 12 instead of being deformed.

  When the holographic recording medium 3 is removed from the pair of holding members 21 ′ after the recording layer 12 is cured, the contraction force Fc suppressed by the pair of holding members 21 ′ is obtained as shown in FIG. To be released. Along with this, the recording layer 12 contracts along the substrate 11 and collects in the central portion 12b, so that the concave central portion 12b of the recording layer 12 swells in the thickness direction. As a result, as shown in FIG. 12B, the recessed central portion 12b is deformed until it has the same thickness as the peripheral edge portion 12a, and the surface of the recording layer 12 becomes a flat surface.

  According to the above, the surface of the recording layer 12 can be flattened even with the holographic recording medium 3 without a spacer.

The present invention is not limited to the above embodiments, and can be used in various forms as exemplified below.
In each of the above embodiments, the present invention is applied to the manufacture of a rectangular holographic recording medium. However, the present invention is not limited to this. The present invention may be applied to the manufacture of a disk-shaped holographic recording medium on which is formed. For example, as shown in FIG. 13A, when the present invention is applied to manufacture of a disk-shaped holographic recording medium 4 having spacers 14 and 15 on the inner and outer peripheral edges, the first embodiment is used. As described above, the central portion C31 of the disc-shaped contact surface C3 that contacts the disc-shaped substrate 11 ″ of the holding member 21 ″ protrudes, and the peripheral portion (the inner peripheral portion and the peripheral portion of the recording layer 12 ″ of the contact surface C3. The inner peripheral edge C32 and the outer peripheral edge C33 corresponding to the outer peripheral edge) may be recessed, where “the central portion C31 in the disc-shaped contact surface C3” is substantially equal from the inner peripheral edge and the outer peripheral edge. A ring-shaped part at a distance.

  By the way, since the disk-shaped holographic recording medium 4 has a larger volume at the outer peripheral portion than at the inner peripheral portion, the contraction force generated after the holographic recording medium 4 is removed from the holding member 21 ″ is reduced from the inner peripheral portion. 13 (a), the most projecting position of the central portion C31 of the contact surface C3 is greater than the contracting force toward the radially outer side than the contracting force toward the radially outer side. The intermediate point CP between the inner peripheral end and the outer peripheral end is preferably slightly shifted toward the center CA of the holographic recording medium 4.

  According to this, when the holographic recording medium 4 is removed from the holding member 21 ″ after the respective steps as in the first embodiment, as shown in FIG. 13B, the recording layer 12 ″ The outer contractive force Fc1 that is radially inward from the outer peripheral edge and the inner contractive force Fc2 that is smaller than the outer contractive force Fc1 that is radially outward from the inner peripheral edge work. As a result, the portion of the recording layer 12 ″ closer to the center CA than the intermediate point CP swells in the thickness direction, and the inner peripheral edge and the outer peripheral edge of the recording layer 12 ″ shrink in the thickness direction. As shown in c), the surface of the recording layer 12 ″ is a flat surface.

  When manufacturing a disc-shaped holographic recording medium without a spacer, the recessed inner peripheral edge C32 and outer peripheral edge C33 are formed flat on the contact surface C3 of the holding member 21 ″ in FIG. do it.

  In the above embodiment, the spacers 13 are provided separately from the respective substrates 11, but the present invention is not limited to this. For example, as shown in FIG. 14A, a bulging portion 11a integrally formed on one of a pair of substrates 11, more specifically, a bulging portion 11a protruding from one substrate 11 toward the other substrate 11 is provided. It may be used as a spacer. In this case, the tip of the bulging portion 11a and the other substrate 11 may be joined with an adhesive.

  Further, as shown in FIG. 14B, the bulging portions 11 b and 11 c that are integrally formed on each of the pair of substrates 11, specifically, protrude from one substrate 11 toward the other substrate 11. The bulging portion 11b and the bulging portion 11c protruding from the other substrate 11 toward the one substrate 11 may be used as spacers. In this case, the tip surfaces of the bulging portions 11b and 11c may be joined with an adhesive.

  In the above embodiment, the pressing device 22 is employed as the force applying means, but the present invention is not limited to this, and for example, a force may be applied to the holding member by tightening a pair of holding members with bolts and nuts. .

  In the embodiment, the recess 21c for positioning the temporary assembly case 1 'is formed in the holding member 21, but the present invention is not limited to this, and the recess 21c may not be formed.

  In the embodiment, the substrate 11 is held on the holding member 21 by vacuum suction, but the present invention is not limited to this, and may be held using, for example, a reversible adhesive, magnetic force, electrostatic attraction, or the like.

  In the above embodiment, the spacers 13 are bonded to the respective substrates 11 before the holding step, but the present invention is not limited to this. For example, after each substrate 11 is held by each holding member 21 (after the holding step), the spacers 13 each coated with an adhesive may be bonded to one substrate 11.

  In the above-described embodiment, the holographic recording medium manufacturing apparatus and manufacturing method in which the recording layer is a recording layer in which a volume hologram is recorded using interference fringes caused by interference of a plurality of laser beams have been described as an example. The same applies to an optical recording medium manufacturing apparatus and manufacturing method provided for the purpose of recording information, for example, an optical recording medium manufacturing apparatus and manufacturing method used for an optical information recording method using a two-photon reaction. The effect can be demonstrated.

It is a disassembled perspective view which shows the holographic recording medium manufactured with the manufacturing apparatus which concerns on 1st Embodiment. It is a schematic front view which shows the manufacturing apparatus which manufactures a holographic recording medium. It is a perspective view which shows the detail of a holding member. It is sectional drawing shown in comparison with the completed holographic recording medium in the shape of the bottom face of a holding member. It is sectional drawing which shows the process of hold | maintaining a temporary assembly case. It is explanatory drawing which shows the process of inject | pouring a photosensitive solution into a temporary assembly case. It is sectional drawing which shows the process of hardening a photosensitive solution. FIG. 4 is a cross-sectional view (a) showing a state immediately after the holographic recording medium is removed from the holding member, and a cross-sectional view (b) showing a state in which the surface of the recording layer is flattened by contraction of the recording layer. It is sectional drawing which shows the holding member which concerns on 2nd Embodiment. It is sectional drawing which shows the process of hold | maintaining a board | substrate with a holding member. It is sectional drawing which shows the process of hardening the photosensitive solution inject | poured between each board | substrate. FIG. 4 is a cross-sectional view (a) showing a state immediately after the holographic recording medium is removed from the holding member, and a cross-sectional view (b) showing a state in which the surface of the recording layer is flattened by contraction of the recording layer. A sectional view (a) showing a holding member used for manufacturing a disc-shaped holographic recording medium, a sectional view (b) showing a state immediately after the holographic recording medium is removed from the holding member, and a contraction of the recording layer It is sectional drawing (c) which shows the state in which the surface of the recording layer became flat. They are sectional drawing (a) which shows the modification in which a spacer is integrally formed in one board | substrate, and sectional drawing (b) which shows the modification in which a spacer is integrally formed in each board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Holographic recording medium 2 Manufacturing apparatus 11 Substrate 11f Outer surface 12 Recording layer 12a Peripheral part 12b Central part 13 Spacer 21 Holding member 21c Recess 22 Pressing device 23 Injection apparatus 25 Vacuum suction apparatus C1 Bottom surface C11 Central part C12 Annular part C13 Flat surface L Photosensitizer

Claims (10)

An apparatus for manufacturing an optical recording medium, comprising: a recording layer on which information is recorded in volume by a laser beam; and a pair of substrates sandwiching the recording layer,
A pair of holding members having a contact surface that holds the substrates in a state where a gap is left between the substrates and is in close contact with an outer surface of the substrate in a state where the substrates are held;
An injection device for injecting a photosensitive solution for forming the recording layer between the substrates,
The adhesive force between the substrate and the contact surface of the holding member is maintained until the photosensitive solution between the substrates is cured to form the recording layer, and
The apparatus for manufacturing an optical recording medium, wherein the contact surface is curved so that a central portion of the contact surface of the holding member protrudes toward the substrate. A recording layer in which information is recorded in volume by a laser beam; a pair of substrates sandwiching the recording layer; a spacer disposed between the pair of substrates and covering a peripheral surface of the recording layer; An optical recording medium manufacturing apparatus comprising:
A pair of holding members that hold the outer surface of the substrate in close contact with the contact surface;
A force applying means for applying a force to the holding member so that the pair of holding members come close to each other in a state in which each of the substrates sandwiching the spacer is sandwiched between the pair of holding members;
An injection device for injecting a photosensitive solution for forming the recording layer into a space formed by each substrate and spacer; and
The adhesion force between the substrate and the contact surface of the holding member and the force applied to the holding member by the force applying means are maintained until the photosensitive solution in the space is cured to form the recording layer. Composed and
The contact surface of the holding member is formed to be curved so that a central portion protrudes toward the substrate and a portion corresponding to a peripheral portion of the recording layer is recessed in a direction away from the substrate. An optical recording medium manufacturing apparatus.   The apparatus for manufacturing an optical recording medium according to claim 1, wherein the recording layer is a recording layer on which a volume hologram is recorded using interference fringes due to interference of a plurality of laser beams.   The apparatus for manufacturing an optical recording medium according to claim 3, wherein a vacuum suction device for bringing the substrate into close contact with the contact surface by vacuum suction is connected to the pair of holding members.   The apparatus for manufacturing an optical recording medium according to claim 4, wherein the recording layer has a thickness of 200 μm or more. A method for producing an optical recording medium comprising: a recording layer on which information is recorded in volume by a laser beam; and a pair of substrates sandwiching the recording layer,
A pair of holding members having contact surfaces curved so that the central portion protrudes toward the substrate holds the outer surface of each substrate in close contact with each contact surface while leaving a gap between the substrates. Holding process;
An injection process for injecting a photosensitive solution for forming the recording layer between the substrates;
A curing step for curing the photosensitive solution,
The method of manufacturing an optical recording medium, wherein the holding step is continued until the injection step and the curing step are completed. A recording layer in which information is recorded in volume by a laser beam; a pair of substrates sandwiching the recording layer; a spacer disposed between the pair of substrates and covering a peripheral surface of the recording layer; A method of manufacturing an optical recording medium comprising:
The outer surface of each substrate is formed by a pair of holding members having a contact surface curved so that a central portion protrudes toward the substrate and a portion corresponding to the peripheral portion of the recording layer is recessed in a direction away from the substrate. A holding step for holding in contact with each contact surface;
A force applying step of applying a force to the holding member so that the pair of holding members come close to each other in a state where each of the substrates sandwiching the spacer is sandwiched between the pair of holding members;
An injection step of injecting a photosensitive solution for forming the recording layer into a space formed by each substrate and the spacer;
A curing step for curing the photosensitive solution,
The method of manufacturing an optical recording medium, wherein the holding step and the force applying step are continued until the injection step and the curing step are completed.   8. The method of manufacturing an optical recording medium according to claim 6, wherein the recording layer is a recording layer on which a volume hologram is recorded using interference fringes due to interference of a plurality of laser beams.   9. The method of manufacturing an optical recording medium according to claim 8, wherein, in the holding step, the substrate is brought into close contact with the holding member by vacuum suction. The method for manufacturing an optical recording medium according to claim 9, wherein the recording layer has a thickness of 200 μm or more.

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