JP2006221767A - Optical recording medium and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical recording medium for manufacturing a high reliable optical recording medium, of which the decentering of each recording layer formed in each of a plurality of sheet substrates is suppressed, and is free from a complicated step. <P>SOLUTION: Respective sheet substrates 10A-10C are laminated with a superposition device 70 in such a state that a recording layer is formed on one surface and a non-hardened adhesives layer is formed on the other surface. The centering of each sheet substrates is performed by the superposition device 70 before a step for curing the adhesives layer. The adhesives layer is then cured, thereafter a punch device 60 collectively punches out three layer sheet substrates into a disk shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium having a multilayer structure in which a plurality of sheet-like substrates on which recording layers are formed are laminated, and a method for manufacturing the same.

  In recent years, an optical recording medium represented by an optical disk is being applied as a medium for recording various kinds of information in fields such as computers and audio visuals. Furthermore, with the spread of mobile computers and the diversification of information, small and large capacity optical recording media are required.

  An optical recording medium records or reproduces information by light, and a substrate (sheet-like base material) has an uneven pattern such as pits and pregrooves (hereinafter referred to as “a groove substrate”) for obtaining a tracking servo signal or the like. Signal pattern ”is also formed. A recording layer is formed on the surface on which the concavo-convex pattern is formed, that is, the concavo-convex pattern surface (also referred to as “information recording surface”), and an organic protective layer or the like is further formed so as to cover the recording layer.

  As an optical recording medium, a single-plate structure or a structure in which two sheet-like substrates are bonded to each other is known. In response to the demand for high density recording, a recording medium having a multilayer structure in which a plurality of recording layers are formed has also been proposed. FIG. 9 shows an example of a multilayer structure, in which a plurality of recording layers 102 and 112 are formed via a transparent intermediate layer 113 and the like. An organic protective layer 103 is formed on the upper surface of the recording layer 102 in the figure.

  The light incident surface for recording / reproducing and erasing information can be applied from the substrate 117 side or the organic protective layer 103 side. Since it is easy to reduce the thickness, it is known that the NA (aperture) of the objective lens of the pickup can be increased, which is advantageous for achieving high density.

The optical recording medium having the multilayer structure as described above and a method for producing the same, or a method for forming a plurality of recording layers are also disclosed in Patent Documents 1 to 5.
International Publication No. 98/02875 Pamphlet JP-A-11-185291 JP 2000-36135 A JP 2003-115130 A JP 2002-288894 A

  However, the conventional proposals according to Patent Documents 1 to 5 have the following problems. This will be described in detail below.

  In Patent Document 1, a polyolefin polymer is used as a main component in order to produce an optical disc (optical recording medium) having high mass productivity, excellent optical characteristics, and excellent mechanical accuracy and mechanical strength. There has been proposed a method of manufacturing an optical disk in which a sheet of material to be processed is processed into a disk shape and an information recording surface made of a curable resin is formed on the sheet. The same document also proposes forming a film made of a curable resin on which an information recording surface and a recording layer are formed on a sheet before being processed into a disk shape, and processing the disk into a disk shape after the formation. Yes. There has also been proposed a method of manufacturing an optical recording medium having a multilayer structure by laminating a plurality of sheets of a photocurable resin having an information recording surface on a disk-shaped sheet.

  The method of forming a curable resin layer having an information recording surface on a sheet described in Patent Document 1 is simply a 2P method (Photo Polymerization method), which is a conventionally known manufacturing method, in which the substrate material is simply limited. It is.

  Further, in the method of this document, no consideration is given to positioning (centering) between substrates on which information recording surfaces are formed. In the optical disc, if the center of each substrate is not positioned with high accuracy, the substrate is decentered, and this decentering causes various problems.

  Next, in Patent Document 2, the recording layer is formed on a sheet having a thickness of 0.3 μm or less, and the recording layer is formed on a rigid support substrate, and the sheet is bonded through a transparent intermediate layer. A multi-layered recording medium has been proposed.

  Although a multilayer structure using such a thin sheet is advantageous in that it can realize a high density of information, in this document, the support substrate on which the recording layer is formed and the sheet are attached as a multilayer structure. Only a combined two-layer structure or a hard disk type in which recording layers are formed on both surfaces of an aluminum substrate is considered.

  Next, in Patent Document 3, as a method for manufacturing an optical recording medium having a multilayer structure, a signal surface (same as an information recording surface) is formed on a sheet and a translucent film is formed on the signal surface. Forming a first substrate by punching, forming a substrate having a signal surface by injection molding or the like, and further forming a second substrate by forming a reflective film on the substrate; and One having a step of bonding the first and second substrates through a transparent adhesive has been proposed.

  However, this method is to bond substrates processed into a predetermined contour shape, and it seems that there is no particular problem if it is a two-layer structure, but a multilayer structure of three or more layers using a sheet as an intermediate layer The intermediate layer sheet becomes a thin sheet of several μm to several tens of μm, and therefore it is difficult to handle the sheet, which is problematic in terms of productivity. The punched sheet generally holds its end, and in the case of a thin sheet, the holding area (end) is extremely narrow.

  Further, the same document also describes that after laminating a sheet and a substrate, the laminate is punched out into a disk shape, but this is only related to a two-layer structure, and has three or more layers. Multi-layer structures are not considered.

  Next, Patent Document 4 discloses that a sheet having a photocurable resin layer on which a signal surface (same as an information recording surface) and a reflective layer are formed is a substrate, and the substrate is divided into three layers via an adhesive. The laminated structure and the manufacturing method thereof have been proposed.

  This multi-layer structure has been proposed for the problem that a transfer failure occurs in injection molding when the substrate thickness is 300 μm or less, but in this document, no consideration is given to punching a sheet.

  In addition, as described above, regarding the sheet holding, if the sheet is thick, the sheet end portion or the ineffective area is clamped (for example, mechanical holding or holding by a vacuum chuck) so that the sheet can be held well. However, in the case of a multilayer structure, it is necessary to make the thickness of each sheet several μm to several tens μm, which is considered to be difficult to hold the sheet. This means, for example, that thin sheets cannot be favorably stacked in the bonding step.

  The manufacturing method of Patent Document 4 is similar to Patent Document 1 in that the material of the photocurable resin is simply limited in the 2P method, which is a conventionally known manufacturing method. Manufacturing a recording medium is a known technique.

  Next, Patent Document 5 proposes a method in which two or more light transmissive films are further bonded to a disk-shaped substrate having a reflection layer or the like formed on the signal surface, and these films are punched into a disk shape. This manufacturing method is characterized in that after a film is bonded to a substrate, a film is formed on the film to form a signal surface. When a multilayer structure is manufactured by this manufacturing method, one substrate is used. (1) A film is laminated, (2) a signal surface is formed on the film, (3) the film is punched into a disk shape, and (4) a recording layer is formed on the signal surface. It is necessary to repeat the process of (4), a manufacturing process is complicated, and it is disadvantageous for productivity improvement. That is, the manufacturing method described in this document focuses on manufacturing an optical recording medium having a two-layer structure, and is not suitable for manufacturing a multilayer structure having three or more layers.

  The present invention has been made in view of the above-described problems, and an object thereof is high-reliability optical recording in which eccentricity of each recording layer formed on each of a plurality of sheet-like substrates is suppressed. An object of the present invention is to provide an optical recording medium manufacturing method that can manufacture a medium and does not involve complicated steps. Another object of the present invention is to provide a highly reliable optical recording medium in which the eccentricity of each recording layer formed on each of a plurality of sheet-like substrates is suppressed.

  In order to achieve the above object, the method for producing an optical recording medium of the present invention comprises a step of forming a recording layer having a concavo-convex pattern on the surface of a sheet-like substrate, and the sheet-like substrate on which the recording layer is formed. A plurality of the plurality of sheet-like base materials that are superposed in a state of being positioned with respect to each other, and a step of collectively processing the plurality of superposed sheet-like substrates into a predetermined contour shape.

  According to the manufacturing method of the present invention, since a plurality of sheet-like base materials are collectively processed into a predetermined contour shape, it is difficult for positional deviations between the recording layers to occur. A highly reliable optical recording medium in which the eccentricity of the recording layer is suppressed can be manufactured. Moreover, since each sheet-like base material is not laminated one layer at a time, the manufacturing process can be simplified. The optical recording medium of the present invention manufactured by such a manufacturing method of the present invention is highly reliable with the eccentricity of each recording layer suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing an example of the configuration of an optical recording medium manufactured by the manufacturing method of the present invention. FIG. 2 is a perspective view schematically showing the optical recording medium of FIG.

  As shown in FIGS. 1 and 2, an optical recording medium 50, which is an optical disk, includes a support substrate 17 made of, for example, transparent polycarbonate as a base, and a three-layer information recording substrate 15A sequentially stacked on the support substrate 17. , 15B, 15C, and a protective coating layer 58 is formed on the top surface of the information recording substrate 15C.

  Each of the information recording substrates 15A to 15C has a recording layer 16, and one recording layer 16 is also formed on the surface of the support substrate 17. Therefore, the optical recording medium 50 of this embodiment has four recording layers. It has a structure (four-layer structure) including a recording layer 16 as a layer. The information of each layer can be reproduced by irradiating each recording layer 16 with laser light from, for example, the protective coating layer 58 side and reading the change in the reflected light.

  Note that the manufacturing method described in the present embodiment is mainly intended to suppress the eccentricity of the recording layer 16 of each of the information recording substrates 15A to 15C, and therefore there is no recording layer 16 on the support substrate 17. Also good.

  Each of the information recording substrates 15A, 15B, and 15C is made of a sheet-like base material 10A, 10B, or 10C (hereinafter, also simply referred to as the sheet-like base material 10 without being distinguished from each other) having a recording layer 16 formed on the surface. Since the configuration is substantially the same for each of the substrates 15A to 15B, the information recording substrate 15A will be described below as an example.

  In the information recording substrate 15A, the sheet-like base material 10A is, for example, a polycarbonate sheet material having a thickness of about 15 μm, and a signal pattern 14 having a concavo-convex pattern is formed on the surface (upper surface in the drawing). A recording layer 16 is formed on the surface of the signal pattern 14 by, for example, sputtering. Since the recording layer 16 is a thin film having a thickness of about 10 nm, for example, the recording layer 16 is also uneven corresponding to the unevenness of the signal pattern 14. In addition, the recording layer 16 on the surface of the support substrate 17 is configured similarly to the recording layer 16 of the recording information substrate 15A.

  In the present specification, the “recording layer” intends a layer having at least a function of recording information. Optical discs are roughly classified into a read-only type, a write-once type that can be recorded only once, and a rewritable type that can rewrite information, and the names of layers for recording information may be different. For example, in the case of a read-only type, a layer for recording information is usually called a “reflection layer”, but the “recording layer” in this specification includes this reflection layer.

  An adhesive layer 42 is formed between the support substrate 17 and the information recording substrate 15A and between the information recording substrates, and the substrates are bonded to each other. As the adhesive, for example, a thermosetting adhesive, a two-component adhesive, a hot melt adhesive, or a pressure-sensitive adhesive is preferable. As the protective coat layer 58, for example, an ultraviolet curable resin can be used.

  Next, several apparatuses for manufacturing the optical recording medium 50 will be described with reference to FIGS.

  In FIG. 3, a forming apparatus 20 for forming the signal pattern 14 on the sheet-like base materials 10 </ b> A to 10 </ b> C, a film-forming apparatus 30 for forming the recording layer 16 on the signal pattern 14, and the sheet-like base material 10. A roller 24, which is a conveying means, is shown.

  The molding apparatus 20 includes a stamper 23 that forms a predetermined uneven pattern on one surface of the long sheet-like base material 10 drawn from the roll 19 and a pair of support members 21 a and 21 b that sandwich the sheet-like base material 10. Have. The stamper 23 is a precision mold attached to one support member 21a, and is configured to be heated by a heating means (not shown). In the molding apparatus 20 configured as described above, the sheet-like substrate 10 is pressed and pressed by driving the pair of support members 21a and 21b and sandwiching the sheet-like substrate 10 in a state where the stamper 23 is heated. By heating, the uneven pattern (signal pattern 14) is transferred to the surface of the sheet-like substrate 10.

  In addition, the shaping | molding apparatus 20 may have a means to cool the sheet-like base material 10 to which the uneven | corrugated pattern was transcribe | transferred as needed. Further, the molding conditions such as heating temperature, pressure, cooling time, and movement distance of the stamper 23 in the transfer process are appropriately determined in consideration of the shape of the signal pattern, the material of the sheet-like substrate 10, the sheet thickness, and the like. There is no particular limitation as long as the optimum condition is selected.

  The film forming apparatus 30 is a sputtering apparatus that forms the recording layer 16 on the signal pattern surface of the sheet-like substrate 10 that has been conveyed. The film forming apparatus 20 is not limited to the one that performs sputtering, and may be other various film forming apparatuses, and details thereof will be described later.

  FIG. 4 shows an example of an apparatus for forming an adhesive layer on the sheet-like substrate 10, and adhesive application apparatuses 40A, 40B, and 40C having different configurations are shown in FIGS. 4 (a), 4 (b), and 4 (c), respectively. ).

  The adhesive application device A has rollers 45 a, 45 b, 45 c that convey the sheet-like substrate 10 on which the recording layer 16 is formed, and one of the rollers 45 b is filled with an uncured adhesive 48. Arranged in the tank 41. Thereby, the adhesive agent 48 adheres to both surfaces of the sheet-like base material 10 which passed the roller 45b. The adhering adhesive 48 is adjusted to a predetermined thickness by a blade 43 disposed so as to face the sheet-like substrate 10 therebetween. In the present embodiment, the adhesive on the recording layer 16 side (lower surface side in the drawing) is completely removed, and the adhesive layer 42 having a predetermined thickness (for example, about several μm) remains only on the upper surface side in the drawing of the sheet-like substrate 10. It is. The blade 43 may be constituted by a doctor knife or the like.

  An apparatus as shown in FIGS. 4B and 4C can be used instead of the adhesive application apparatus A. In the adhesive application device B of FIG. 4B, a pair of rollers 45a and 45b are arranged to face each other with the sheet-like base material 10 interposed therebetween, and on the upstream side of the rollers 45a and 45b, the sheet-like base material 10 is disposed. A nozzle 47 for supplying an adhesive 48 is disposed on the upper surface. In addition, the sheet-like base material 10 has a recording layer 16 on the lower surface side as in the above configuration. The adhesive 48 on the upper surface of the sheet-like substrate supplied from the nozzle 47 is pressurized by the rollers when passing through the rollers 45a and 45b, and becomes an adhesive layer 42 having a predetermined thickness.

  The adhesive application device 40C is a modification of the adhesive application device 40B. The nozzle 47 is disposed on the rollers 45a and 45b, and the adhesive 48 from the nozzle 47 is directly supplied to the roller 45a. It has become.

  In FIG. 5, an overlapping device 70 that laminates three layers of the sheet-like base material 10 on which the recording layer 16 and the adhesive layer 42 are formed by passing through the various devices 20, 30, 40 and the like described above, A punching device 60 for punching three-layer sheet-like base materials 10A to 10C into a disk shape is shown.

  The overlapping device 70 includes a plurality of tension rollers 76 that transport each of the sheet-like base materials 10 </ b> A to 10 </ b> C, and a control unit (not shown) for controlling the driving of the tension rollers 76. Each tension roller 76 is configured to be capable of forward and reverse rotation for alignment of a sheet-like base material, which will be described later, and can transport the sheet-like base material bidirectionally. The overlapping device 70 also has two guides 71 that overlap the three-layer sheet-like base materials 10A to 10C in a close contact state.

  In addition, in FIG. 5, each guide 71 is only shown typically, but, for example, three layers of sheet-like base materials are arranged to face each other, and each of the upper and lower sheet-like base materials 10A and 10C. You may be comprised by the roller member which carries out point contact. The guide 71 may also have a mechanism for preventing air from remaining between the sheet-like substrates. Moreover, you may have a mechanism which positions each sheet-like base material 10A-10C regarding the width direction of a sheet-like base material, ie, the direction which is in a sheet surface and orthogonal to a conveyance direction.

  In order to align the position of the sheet-like substrate, each sheet-like substrate 10 is provided with an alignment mark 13 as shown in FIG. Specifically, three alignment marks 13 are provided outside the area to be punched or at least outside the information recording area of the disc. The three alignment marks 13 are, for example, equal to each other in the circumferential direction of the disc. Arranged at intervals.

  The alignment mark 13 can be formed by using, for example, the molding apparatus 20 (see FIG. 3) described above. That is, a protrusion for forming the alignment mark is provided outside the effective area of the stamper 23, and the alignment mark 13 is formed on the sheet-like substrate 10 together with the signal pattern 14 during the transfer process by the stamper 23. There may be.

  The shape of the alignment mark 13 is not particularly limited as long as it can be detected with high accuracy. In addition to the cross shape shown in the figure, a cross system with a slit, or a star shape It may be.

  Referring again to FIG. 5, two sensors 74 for detecting the alignment mark 13 are arranged in a region between the two guides 71 as a component of the overlapping device 70. The position information of the alignment mark 13 detected by the sensor 74 is sent to a control means (not shown) of the superposition apparatus 70, and the control means centers the sheet-like base materials 10A to 10C based on this information. Therefore, the tension roller 76 and the like are driven. Each sheet-like base material 10A to 10C thus positioned is held by a guide 71 so that the positioning state is maintained.

  The punching device 60 is a punching press disposed in a region between two guides 71, and punches the stacked three-layer sheet-like base materials 10A to 10C in a lump. Specifically, the punching device 60 includes a pair of press members 61a and 61b that sandwich and punch a sheet-like base material. The contour shape of the sheet punched by the pair of press members 61a and 61b is a disk shape, that is, a circular shape.

  Next, a method for manufacturing the optical recording medium 50 according to the present embodiment (see FIG. 7) and the operation of each device described above will be described below. In FIG. 7, the sheet-like base material 10 and the recording layer 16 are schematically shown without an uneven pattern.

  First, the sheet-like base material 10 pulled out from the roll 19 (see FIG. 3) is fed into the molding apparatus 20 by the roller 24, and the molding apparatus 20 is driven in a state where the driving of the roller 24 is stopped. By driving the molding apparatus 20, the stamper 23 is pressed against one surface of the sheet-like substrate 10, and a predetermined signal pattern 14 is formed on the sheet-like substrate 10 (see FIG. 7A).

  Next, the roller 24 is driven again to convey the sheet-like substrate 10. This transfer operation is performed until the formed signal pattern 14 reaches a predetermined position in the film forming apparatus 30. Then, by driving the film forming apparatus 30, the recording layer 16 is formed on the surface of the signal pattern 14 (see FIG. 7B).

  Next, for example, an adhesive layer 42 having a predetermined thickness is formed on the sheet-like substrate 10 by passing through the adhesive application device 40A of FIG. 4A (see FIG. 7C). The adhesive layer 42 is formed on the surface of the sheet-like substrate 10 opposite to the recording layer 16.

  Next, the sheet-like base materials 10A to 10C on which the recording layer 16 and the adhesive layer 42 are formed in this way are sent to the guide 71 of the overlapping device 70 via the tension roller 76 (see FIG. 5). It is. Here, the three-layer sheet-like base materials 10A to 10C held by the two guides 71 are in close contact with each other via the adhesive layer 42, as shown in FIG. At this point, the adhesive is not yet cured, and therefore each sheet-like substrate can be centered.

  That is, in the close contact state as shown in FIG. 7D, the sensor 74 of the overlapping device 70 detects the position of the alignment mark 13 provided on each sheet-like base material. Based on the detection result, final positioning (centering) of the sheet-like base materials 10A to 10C is performed by the tension roller 76 or the guide 71. By this positioning, the centers of the punched areas in the respective sheet-like base materials are aligned.

  When the final positioning is completed, the adhesive layer 42 is then cured. The process for curing the adhesive is determined by the type of adhesive used. For example, when a thermosetting material is used, Heating corresponds to this.

  Next, after the adhesive layer 42 is cured, the punching device 60 is driven to collectively punch the three layered sheet-like base materials into a disk shape. Thereby, a laminated body 50 ′ in which the three layers of sheet-like base materials 10 </ b> A to 10 </ b> C are laminated is manufactured (see FIG. 7D).

  Next, as shown in FIG. 7 (e), the signal substrate 14 and the recording layer 16 are formed in advance, and the support substrate 17 punched out into a disk shape and the laminated body 50 ′ are interposed through the adhesive layer 42. And paste them together. Then, by forming the protective coating layer 58 on the uppermost sheet-like substrate 10C, the optical recording medium 50 of the present embodiment is manufactured.

  The protective coat layer 58 may be formed, for example, by applying an ultraviolet curable resin on a substrate by a spin coating method and irradiating the ultraviolet ray to cure the resin.

  As described above, in the manufacturing method of the present embodiment, the three-layer sheet-like base materials 10A to 10C that are positioned with each other by the overlapping device 70 and fixed in the positioned state are collectively collected by the punching device 60. Since it is punched into a disk shape, the positional deviation between the respective sheet-like base materials 10A to 10C, in other words, the positional deviation between the recording layers 16 of the sheet-like base material is minimized, and as a result, the eccentricity is reduced. The suppressed highly reliable optical recording medium 50 is obtained. Moreover, since the manufacturing method of this embodiment superimposes the 3 layer sheet-like base materials 10A-10C simultaneously, that is, since each sheet-like base material is not laminated | stacked one layer at a time, manufacture Simplification of the process is realized.

  The punching of the disc from the sheet is not limited to being performed after the adhesive is cured, but depending on the punching method, that is, depending on the shape of the press die, for example, the punching after the curing has a uniform film thickness. The adhesive layer 42 may be easily obtained.

  Hereinafter, more specific examples of the present invention will be described as examples.

  Polycarbonate sheet-like substrates 10A, 10B, and 10C having thicknesses of 12 μm, 13 μm, and 14 μm were prepared. Each sheet-like substrate was laminated with a protective film having a thickness of 100 μm on one side as a backing material.

  The glass transition point of the polycarbonate resin was 140 ° C., the thermal deformation temperature was approximately 120 ° C., and the temperature of the sheet-like substrate immediately after transfer by the stamper 23 of the molding apparatus 20 was 30 ° C. to 40 ° C.

  In the film forming apparatus 30, a SiN film (reflective layer) was formed as the recording layer 16 by sputtering, and the film thickness was 10 nm. In this sputtering process, a mask was used so that the alignment mark 13 was not formed.

  The light transmittance of each recording layer 16 in each sheet-like substrate can be changed without changing the film thickness by adjusting the pressure during film formation, the gas flow rate, and the supply power. is there. In this example, the transmittance of the four recording layers 16 was increased in the order from the support substrate 17 side toward the outermost surface side in the final optical recording medium 50 state.

  A thermosetting adhesive was used as the adhesive 48, and an adhesive layer 42 was formed using an adhesive application device 40B shown in FIG. The thickness of each adhesive layer 42 was about 3 μm. After applying the adhesive, the protective film of the sheet-like substrate was peeled off.

  By the way, the interlayer distance between the recording layers 16 is defined by the total thickness of the thickness of the adhesive layer 42 and the thickness of the sheet-like substrate 10. In the present embodiment, the adjustment of the interlayer distance is performed by the sheet-like substrate 10. That is, as described above, the thickness of the adhesive layer is made as thin as 3 μm as much as possible, while the thickness of the sheet-like base material is set to several tens of μm. Since the thickness of the adhesive layer is likely to vary compared to the thickness of the sheet-like substrate, such a thin adhesive layer can improve the uniformity of the final interlayer distance. Is advantageous. In addition, adjustment of an interlayer distance can be easily performed only by changing the thickness of each sheet-like base material.

  The contour shape of the disc punched by the punching device 60 was 120 mm in outer diameter and 12 mm in inner diameter. In addition, a polycarbonate support substrate 17 (thickness: 1.1 mm) processed in the same shape in advance was disposed in the lower layer of the three-layer sheet-like substrate in the punching device 60.

  Note that the signal pattern 14 and the recording layer 16 were formed on the support substrate 17 in a separate process. In addition, the inside of the punching device 60 is in a vacuum state so that air or foreign matter does not remain between the sheet-like substrates.

  Subsequently, the three-layer sheet-like base materials were overlapped by the overlapping device 70, and the three-layer sheet-like base materials 10 </ b> A to 10 </ b> C were collectively punched by the punching device 60. Thereafter, the support substrate 17 was bonded to the lower surface of the sheet-like base material 10C. In this example, the curing process of the adhesive layer 16 (adhesive layer for bonding the three sheet-like base materials) was performed before the punching process.

  By the above process, a structure in which the three-layer sheet-like base materials 10A to 10C and the support base material 17 were laminated was obtained. Thereafter, a protective coating layer 58 made of an ultraviolet curable resin is formed on the upper surface of the uppermost sheet-like substrate 10C (strictly, on the upper surface of the recording layer 16) with a thickness of 75 μm by spin coating. Thus, an optical recording medium according to this example was obtained.

  An attempt was made to reproduce information for each recording layer 16 from the protective coating layer 58 side with respect to the manufactured optical recording medium. As a result, reproduction could be performed in each layer without any problem.

  As mentioned above, although this embodiment and the Example have been described with reference to FIGS. 1 to 7, the present invention is not limited to the above description, and various other modifications are possible.

  For example, the material of the sheet-like base material 10 is not particularly limited as long as it is a material that does not interfere optically when recording, reproducing, or erasing the recording layer 16. For example, polyolefin resin or acrylic resin can be used as the thermoplastic resin. In recent years, the wavelength of light used has been reduced to a single wavelength of 785 nm for CD and 660 nm for DVD, and further, 405 nm has been studied for Blu-ray Disc, so there is little absorption or reflection of light in these wavelength ranges, And it is preferable that it is a material which does not produce birefringence easily. The thickness of the sheet-like substrate 10 can be arbitrarily selected in the range of about 1 μm to 300 μm, but is appropriately selected in consideration of the number of recording layers 16 and the dynamic range of the spherical aberration correction mechanism. It is preferable.

  Further, by using a flat sheet-like base material on which no signal pattern 14 or the like is formed as an intermediate layer, the interlayer distance can be adjusted, or the support substrate 17 or the protective coat layer 58 can be used. You can also. Thus, when using a sheet-like base material as a protective coat layer, the punching device 60 is driven in a state where this protective coat layer is further laminated in addition to the three-layer sheet-like base materials 10A to 10C. The layers may be punched together.

  In the above embodiment, the sheet-like substrate 10 is wound around the roll 19. Thus, although the structure which pulls out a sheet | seat from the roll 19 is preferable at the point of productivity improvement, this invention is not limited to this. For example, a configuration in which sheets cut into a predetermined size are sequentially supplied to the forming apparatus 20 or the like may be employed. The shape of each sheet may be, for example, a quadrangle or a circle, and the presence or absence of the center hole is not particularly limited. The shape of the sheet is not particularly limited as long as it does not hinder positioning and conveyance.

  In FIG. 2, two rollers 24 are shown as the conveying means. However, instead of the rollers 24, a belt conveyor or an industrial conveying robot can be used as the conveying means.

  In addition to the above, the method for forming the signal pattern 14 may be as follows. That is, instead of directly forming a signal pattern on the sheet-like base material 10, a sheet-like base material having a signal pattern formed on a film made of either an ultraviolet curable resin, a thermosetting resin, or a dry photopolymer is used. 10 can be laminated. Alternatively, an uncured (liquid) or semi-cured (sheet-like) resin can be disposed on the stamper to cure the resin and to adhere to the sheet-like substrate. In this case, the resin may be an ultraviolet curable resin, a thermosetting resin, or a dry photopolymer. As materials for UV curable resins, thermosetting resins, and dry photopolymers, acrylic, epoxy, urethane, phenol, or other various modified materials can be used. It is preferable to select a material that has low absorption, and in particular, a photopolymerization initiation absorption region that is different from the wavelength region used for recording, reproduction, or erasing. Furthermore, it is preferable to arrange a protective sheet that can be peeled off in a later step on one surface of the resin. By arranging the protective sheet, the stamper pressurizes the resin through the protective sheet, and the thickness of the sheet to be formed can be made uniform. Further, since the rigidity of the sheet is substantially increased by arranging the protective sheet, there is also an advantage that the conveyance and handling of the sheet are improved.

  In addition, the utilization method of such a protection sheet can be applied variously, for example, in a predetermined process, a protection sheet can be temporarily affixed on the sheet-like base material 10, and the handleability in the process can also be improved. is there. Thereby, the positioning accuracy of the sheet-like base material 10 may improve. Note that when peeling off the protective sheet, static electricity may be generated and dust or the like may adhere to the protective sheet. Therefore, it is preferable to use a protective sheet that has been subjected to antistatic treatment, or to perform the peeling operation in a static elimination environment. .

  The film forming method for forming the recording layer 16 is not particularly limited, and other than sputtering, vapor deposition, CVD, dipping, spin coating and the like can be used.

  As the material of the optical recording layer, at least one kind of materials such as Te, In, Ga, Sb, Se, Pb, Ag, Au, As, Co, Ni, Mo, W, Pd, Ti, Bi, Zn, Si, etc. Alloys and the like composed of the above are widely known in general, and many materials already exist as known techniques.

  In addition, alloys made of at least one of Tb, Fe, Co, Cr, Gd, Dy, Nd, Sm, Ce, Ho, and other rare earth-transition metal alloys are often used as magneto-optical recording materials. Many of these materials already exist as known techniques.

  Al, Al alloys, Si, SiN, Ag, Ag alloys, and the like are used as the material for the reflective layer for the reproduction-only type, and many materials already exist as known techniques. Furthermore, organic dye-based materials such as cyanine-based, phthalocyanine-based, and azo-based materials can be used as the recording layer.

  The film thickness of the recording layer or the reflective layer can be arbitrarily set, but light attenuation occurs in each recording layer and the reflective layer from the light incident surface side, so that the transmittance at the wavelength of the light used is a layer close to the incident surface side. It is desirable that the recording layer and the reflective layer have a composition that does not hinder recording, reproduction, and erasing by adjusting the composition and film thickness of each recording layer and the reflective layer. By optimizing the composition, film thickness, film forming conditions, and the like for each sheet-like base material and supporting substrate, a recording layer and a reflective layer having arbitrary transmittance and reflectance can be formed.

  In FIG. 4, the method of applying the adhesive to the sheet-like substrate 10, in other words, the method of forming the adhesive layer 42 has been described. However, instead of using the apparatus as shown in FIG. 4, the adhesive layer 42 is used. It is also possible to form the adhesive layer 42 by affixing a sheet-like member that functions as a sheet-like base material 10. Further, a sheet-like base material in which an adhesive layer is previously formed on one surface (the surface opposite to the recording layer 16) may be used. Moreover, an adhesive layer can also be formed on both side surfaces of the sheet-like substrate 10.

  In the above embodiment, the adhesive layer 42 is formed in advance before the punching step. However, the adhesive layer 42 can be formed after the punching.

  That is, the sheet-like base materials 10A to 10C and the support substrate 17 are laminated and positioned without the adhesive layer 42 interposed therebetween, and the sheet-like base materials 10A to 10C are punched in that state. Thereby, it becomes a disk shape, and each of the sheet-like base material and the support substrate has a center hole.

  And this center hole is clamped and each sheet-like base material and a support substrate are hold | maintained in the state by which positioning is carried out. Thereafter, for example, the adhesive is allowed to penetrate from the outer periphery of the disk to between the respective sheet-like base materials, and the adhesive is cured in a state where pressure is applied from both sides. Thereby, the adhesive bond layer 42 is formed between base materials.

  In addition, in order to implement | achieve the above-mentioned adhesive penetration | infiltration processes, it is necessary to ensure the space | gap for allowing an adhesive to penetrate | invade between sheet-like base materials etc. in the clamp state.

  According to the method described above, since the size of the gap in the clamped state does not fluctuate, that is, the adhesive layer 42 is formed while the interlayer distance is constant, the thickness of the adhesive layer 42 Variation is less likely to occur, and as a result, the uniformity of the interlayer distance can be improved.

  The method of punching the disc may be a method using laser processing or mechanical cutting in addition to a method using a press die (punching device 60 in FIG. 5). However, the contour shape of the optical recording medium is not limited to the disk shape (circular), but may be a polygonal shape including a rectangle.

  The timing of driving the punching device 60 can also be changed. In the above description, the punching is performed after the adhesive layer 42 is cured. However, the adhesive layer 42 may be cured after the sheet-like substrate is punched. Good.

  With regard to the overlapping device 70, the overlapping device superimposes each sheet-like substrate in a vacuum atmosphere in order to prevent air or foreign matter from being mixed between the sheets when the sheet-like substrates are laminated. It may be a thing. In addition, the overlapping device may include a pair of plate-like pressing members that press and hold the stacked three-layer sheet-like base materials from both sides. Thereby, a sheet-like base material is pressurized by the substantially uniform force in the overlapping region, and as a result, the thickness uniformity of the adhesive layer can be improved. It is also possible to perform punching in a pressurized state.

  In addition, various methods can be employed for bonding the stacked body 50 ′ (see FIG. 5) and the support substrate 17. For example, a stack of three sheet-like base materials and a support substrate 17 before punching may be laminated and punched into a disk shape in that state.

  The alignment mark 13 may be formed. This is because, depending on the reading method of the alignment mark, the reflectance is improved by the film formation and the reading accuracy is increased. It is preferable to provide a plurality of alignment marks 13 outside the effective area of the disk or in an area to be cut at the time of punching from the viewpoint of improving the positional accuracy. However, only one alignment mark 13 may be provided. In this case, for example, one alignment mark may be provided at the center of the disk, and each substrate may be positioned so that each sheet-like substrate coincides with the alignment mark.

  In the above-described embodiment, the positioning is described after the sheet-like substrates are overlapped. However, the alignment is performed before the overlapping, that is, before the sheet-like substrates are brought into close contact with each other. It is also possible. In this case, the guide 71 should just be the structure which can closely_contact | adhere each sheet-like base material thus centered in the centered state. Such a centering and overlapping method is advantageous when the adhesive does not have fluidity or has low fluidity.

  The stamper 23 can be manufactured by a conventionally known method. For reference, an example of a process for manufacturing the stamper 13 will be described with reference to FIG.

  First, as shown in FIG. 8A, a photoresist 81 is applied on a master glass 82 by spin coating. Next, as shown in FIG. 8B, a laser 83 is irradiated to the photoresist 81 to form a signal pattern having a predetermined shape as an exposure portion 84. Next, as shown in FIG. 8C, the exposed portion 84 is alkali-developed, leaving a predetermined signal pattern on the master glass 82. Next, as shown in FIG. 8D, a nickel conductive film 85 is formed on the signal pattern surface or the like. This film formation can be performed by sputtering, for example. Next, as shown in FIG. 8E, an electroformed layer 86 having a thickness of, for example, 0.3 mm is formed on the master glass 82 by performing nickel electroforming. And after grind | polishing the whole back surface (illustrated upper surface) of the electroformed layer 86, as shown in FIG.8 (f), the electroformed layer 86 is peeled from the original glass 82. FIG. Thereby, the stamper 23 to which the predetermined signal pattern is transferred is manufactured.

It is sectional drawing which shows typically an example of a structure of the optical recording medium manufactured by the manufacturing method of this invention. FIG. 2 is a perspective view schematically showing the optical recording medium of FIG. 1. It is a figure which shows typically the shaping | molding apparatus etc. which form a signal pattern. It is a figure which shows typically the structure of the apparatus which forms an adhesive bond layer in a sheet-like base material. It is a figure which shows typically the overlay apparatus etc. which laminate | stack a some sheet-like base material. It is a top view which shows the alignment mark on a sheet-like base material. It is process drawing which shows the manufacturing process of this embodiment. It is process drawing which shows the manufacturing process of a stamper. It is sectional drawing which shows an example of a structure of the conventional optical recording medium.

Explanation of symbols

10, 10A, 10B, 10C Sheet-like base material 14 Signal pattern 16 Recording layer 17 Support substrate 20 Molding device 23 Stamper 30 Film forming device 40A, 40B, 40C Adhesive application device 42 Adhesive layer 50 ′ Laminate 50 Optical recording medium 58 Protective coating layer 60 Punching device 70 Overlay device

Claims (6)

Forming a recording layer having a concavo-convex pattern on the surface of the sheet-like substrate; and
A step of superposing a plurality of the sheet-like base materials on which the recording layer is formed in a state of being positioned with respect to each other;
And a step of collectively processing the plurality of sheet-like base materials superimposed on each other into a predetermined contour shape.   The method for producing an optical recording medium according to claim 1, further comprising an adhesion step of the plurality of sheet-like substrates.   The bonding step is performed by penetrating and curing the adhesive between the sheet-like substrates in the positioning state after the step of collectively processing the plurality of sheet-like substrates into a predetermined contour shape. The method for producing an optical recording medium according to claim 2. In the step of superimposing the plurality of sheet-like substrates, a plurality of the sheet-like substrates are superimposed with an uncured adhesive interposed therebetween,
The method of manufacturing an optical recording medium according to claim 2, wherein in the bonding step, the adhesive is cured before collectively processing the plurality of sheet-like base materials into a predetermined contour shape.   5. The method according to claim 1, further comprising a step of attaching a support substrate to one of the outermost layers of the plurality of sheet-like base materials stacked with an adhesive layer interposed therebetween. The manufacturing method of the optical recording medium of description.   An optical recording medium manufactured by the manufacturing method according to claim 1.

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