JP4410141B2 - Optical information recording medium - Google Patents

Description

  The present invention relates to an optical information recording medium, and more particularly to an optical information recording medium having a printable label surface.

In recent years, a DVD (Digital Versatile Disc) having a recording capacity several times that of a CD (Compact Disc) such as a CD-R / CD-RW is an information recording medium on which information such as images and sounds such as movies are recorded. As widely used. Conventionally, such a DVD has a surface (printing) on which a desired information / image can be printed by a printer or the like on the surface (label surface) of a dummy substrate provided on the side opposite to the side on which recording / reproducing light is incident Layer). Recently, a print layer on the label surface has been expanded to a clamping area provided on the inner peripheral side from the recording area, and a proposal has been made to increase the printable surface to increase the product value.
By the way, in the recordable DVD-R or DVD-RW having a recording layer containing an organic dye, the layer configuration of the recording area and the clamping area is different. For this reason, there is a difference between the contrast of the image printed in the recording area of the print layer and the contrast of the image printed in the clamping area, and as a result, there is a problem that the image appears to have a boundary.
As a method for solving such a problem, for example, a groove having the same shape as a pre-groove for recording / reproduction is formed up to the clamping area, and a dye layer, a reflective layer, and an adhesive layer are sequentially provided thereon. A method for eliminating the boundary between the recording area and the clamping area by forming a layer structure similar to that of the recording area has been reported (see Patent Document 1).

JP 2004-139697 A

However, as in Patent Document 1, a groove having the same shape as a pre-groove that performs recording / reproduction in the recording area is formed up to the clamping area of the DVD, and a dye layer or the like is sequentially provided thereon, If a similar layer structure is to be formed, particularly when an organic dye layer is formed by spin coating or the like, a complicated operation is required, leading to an increase in manufacturing cost.
In addition, it is known that the clamping area around the center hole is a portion where stress concentration is high when a DVD is mounted on or removed from the drive. For this reason, when a recording layer containing an organic dye is provided up to the clamping area, the adhesive force at the interface between the organic dye and the reflective film is increased in the clamping area where the stress concentration is high. Therefore, the adhesiveness between the substrate on which the pregroove is formed and the dummy substrate is lowered, and as a result, the DVD may be damaged.
The present invention has been made to solve such problems.
That is, an object of the present invention is to provide an optical information recording medium in which an image printed on a label surface does not have a boundary due to light reflection, and the bonding strength near the center hole is enhanced. is there.

In order to solve the above-described problem, in the present invention, a groove having a shape different from the pregroove formed in the recording area is formed in the clamping area.
That is, according to the present invention, there is provided an optical information recording medium in which a substrate and a dummy substrate having a printing layer provided on a portion corresponding to the clamping area and the recording area of the substrate are bonded together. A pre-groove for recording / reproduction formed and a dummy groove for non-recording / reproduction formed in a clamping area provided on the inner circumference side of the recording area and having a shape different from that of the pre-groove An optical information recording medium is provided.
Here, in the optical information recording medium to which the present invention is applied, the recording layer and the reflective layer are sequentially formed on the pre-groove surface formed in the recording area, while the dummy groove surface formed in the clamping area. By forming only the reflective layer, the groove shape of the pre-groove and the groove shape of the dummy groove after the reflective layer is formed can be made substantially the same, and the recording area in the printed layer The boundary with the clamping area can be eliminated.
Further, in the optical information recording medium to which the present invention is applied, at least the same shape as the pregroove on the surface opposite to the surface on which the printed layer of the dummy substrate is provided, particularly on the portion corresponding to the clamping area By providing this groove or a groove having the same shape as the dummy groove, the adhesion between the substrate and the dummy substrate can be improved.

In addition, according to the present invention, the recording / reproducing pregroove in which the recording layer and the reflective layer are sequentially laminated on the surface, and the non-recording / reproducing having a shape different from the pregroove in which only the reflective layer is laminated on the surface. A substrate having a dummy groove formed thereon is bonded to a dummy substrate having a printed layer provided on the surface opposite to the adhesive layer through an adhesive layer formed on the reflective layer. An optical information recording medium is provided.
In the optical information recording medium to which the present invention is applied, as described above, the groove depth of the pregroove after the recording layer and the reflective layer are laminated, and the groove depth of the dummy groove where only the reflective layer is laminated, , Are substantially equal.
The recording layer preferably contains an organic dye compound.

Next, according to the present invention, there is provided an optical information recording medium in which a dummy substrate having a printing layer and a recording / reproducing substrate are bonded to each other via an adhesive layer, and the substrate is formed with a tracking pregroove. A recording area and a clamping area in which a dummy groove for non- recording / reproduction is formed. The groove shape of the dummy groove is the same as the groove shape after the reflective layer is formed on the dummy groove and the pregroove. An optical information recording medium is provided which is formed to be shallower than the groove depth of the pregroove so that the groove shape after the recording layer containing the organic dye and the reflective layer are substantially equal to each other is formed. .
Here, in the optical information recording medium to which the present invention is applied, the contrast of the image printed on the portion corresponding to the clamping area of the printing layer formed on the dummy substrate, and the portion corresponding to the recording area. It is characterized in that the difference from the contrast of the printed image is reduced.

Further, according to the present invention, there is provided an optical information recording medium in which a substrate having a recording layer and a dummy substrate are bonded to each other, the tracking pre-groove provided in a recording area on the surface of the substrate and having the recording layer laminated thereon. A dummy groove provided in a clamping area on the substrate surface and formed shallower than the pregroove, and a printed layer provided on the label surface of the dummy substrate so as to cover portions corresponding to the clamping area and the recording area And an optical information recording medium characterized by comprising:
Here, in the optical information recording medium to which the present invention is applied, the amount of reflected light in the recording area in which the recording layer containing the organic dye and the reflective layer are sequentially formed on the pregroove, and only the reflective layer is provided on the dummy groove. The amount of reflected light of the formed clamping area is substantially equal, and the problem of a boundary between the recording area and the clamping area in the printing layer is solved.

  According to the present invention, the bonding strength in the vicinity of the center hole of the optical information recording medium is enhanced, and further, there is no boundary between the images printed on the label surface due to the reflection of light.

Hereinafter, the best mode (embodiment) for carrying out the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. Further, the drawings used are used for explaining the present embodiment, and do not represent actual sizes.
FIG. 1 is a diagram for explaining an optical information recording medium to which an embodiment of the present invention is applied. FIG. 1A is a plan view seen from the signal surface side of the substrate 10 on which the recording / reproducing light of the optical information recording medium 100 is incident. FIG. 1B is a plan view of the dummy substrate 16 provided with the printing layer 17 of the optical information recording medium 100 as viewed from the label surface side.
As shown in FIG. 1A, the optical information recording medium 100 has a circular substrate 10, and a center hole 11 is provided at the center of the substrate 10. Around the center hole 11, a stamper pressing groove 12 serving as a mold pressing portion in injection molding and a stack rib 13 used when the optical information recording medium 100 is mounted in a predetermined drive are provided concentrically. It has been. As shown in FIG. 1A, a clamping area 14 is formed on the inner peripheral side of the stack rib 13, and a recording area 15 is formed on the outer peripheral side of the stack rib 13.
Next, as shown in FIG. 1B, a dummy substrate 16 laminated on the substrate 10 is provided on the label surface side of the optical information recording medium 100, and a printing layer 17 that can be printed by a printer or the like. Is formed so as to cover the clamping area 14 and the recording area 15.

Next, the layer structure of the optical information recording medium 100 will be described.
FIG. 2 is a cross-sectional view for explaining the vicinity of the clamping area 14 of the optical information recording medium 100. As shown in FIG. 2, the optical information recording medium 100 includes a substrate 10 made of a light transmissive material provided with a center hole 11, and a dummy substrate 16 made of the same material as the substrate 10. It has the structure bonded together via. A tracking pre-groove 101 having a predetermined shape is formed concentrically or spirally on the surface of the substrate 10. Further, in the recording area 15 extending from the stack rib 13 to the outer peripheral side, a predetermined pattern is provided as necessary for pre-pits in which information is recorded or for tracking or addressing.
In the clamping area 14 on the surface of the substrate 10, a dummy groove 102 having a shape different from that of the pregroove 101 formed in the recording area 15 is formed in the range up to the stamper pressing groove 12 on the inner peripheral side.
On the pregroove 101 formed in the recording area 15, a dye layer 103 containing an organic dye compound and a reflective layer 104 are sequentially laminated. On the other hand, only the reflective layer 104 is provided on the dummy groove 102 formed in the clamping area 14.
A printed layer 17 is provided on the surface of the dummy substrate 16 so as to cover the clamping area 14 and the recording area 15 of the substrate 10, and a predetermined image can be printed by a printer or the like. A groove 161 having the same shape as the pregroove 101 formed on the surface of the substrate 10 and a groove 162 having the same shape as the dummy groove 102 are formed on the surface of the dummy substrate 16 on the adhesive layer 18 side.

As shown in FIG. 2, in the optical information recording medium 100 to which the present embodiment is applied, the shape of the dummy groove 102 formed in the clamping area 14 on the surface of the substrate 10 is formed in the recording area 15. It is characterized by being different from the shape of the pregroove 101. In other words, the depth of the dummy groove 102 is formed so as to be shallower than the depth of the pre-groove 101.
As will be described later, when the dye layer 103 containing the organic dye compound is formed on the surface of the pregroove 101, the organic dye compound is accumulated in the pregroove 101 after the dye layer 103 is formed. The shape of the depression on the surface of 103 is substantially the same as the shape of the surface of the dummy groove 102 where the dye layer 103 is not formed.
Since the shape of the depression on the surface of the dye layer 103 and the shape of the surface of the dummy groove 102 where the dye layer 103 is not formed are substantially the same, the clamping area 14 and the recording after the reflective layer 104 is formed on these surfaces are recorded. The shape of the recess with the area 15 is also substantially the same.
That is, the depth (Da) and the half-value width (Wa) of the depression when the reflective layer 104 is provided on the surface of the dye layer 103 in the recording area 15 are determined by providing the reflective layer 104 on the surface of the dummy groove 102 in the clamping area 14. In this case, the depth (Db) and the half-value width (Wb) of the dent are substantially the same.
As a result, since the amount of reflected light between the clamping area 14 and the recording area 15 becomes substantially equal, the image printed on the portion corresponding to the clamping area 14 of the printing layer 17 and the portion corresponding to the recording area 15 are printed. The problem that the boundary with the image is not observed and the image printed on the printing layer 17 appears to have a boundary is solved.
The method of forming the dummy groove 102 in the same manner as the shape of the surface depression after the dye layer 103 is formed is not particularly limited. For example, there is a method in which the shape after the dye layer 103 is formed on the pregroove 101 in the recording area 15 is measured in advance, and the shape of the dummy groove 102 is determined based on the measured shape.

Further, in the optical information recording medium 100 to which this embodiment is applied, the dye layer 103 containing the organic dye compound is not formed on the surface of the dummy groove 102 formed in the clamping area 14 on the surface of the substrate 10. It has the characteristics.
That is, since the dye layer 103 is not formed on the surface of the dummy groove 102 near the center hole 11, the adhesion between the substrate 10 and the dummy substrate 16 in the clamping area 14 where stress concentration is high is improved. As a result, it is possible to prevent the vicinity of the center hole 11 from being damaged when the optical information recording medium 100 is attached to or detached from the drive.

  Further, in the present embodiment, a groove 161 having the same shape as the pregroove 101 formed on the surface of the substrate 10 and a groove 162 having the same shape as the dummy groove 102 are formed on the surface of the dummy substrate 16 on the adhesive layer 18 side. As a result, the adhesion of the dummy substrate 16 can be improved. In particular, since the grooves 162 having the same shape as the dummy grooves 102 of the substrate 10 are formed in a range corresponding to the clamping area 14 of the substrate 10, the substrate 10 and the dummy substrate 16 of the clamping area 14 having a high stress concentration. The adhesion can be further improved.

Next, the material of each layer constituting the optical information recording medium 100 to which this embodiment is applied will be described.
The substrate 10 is made of a light transmissive material. Examples of the light transmissive material include polycarbonate resins, polymethyl methacrylate resins, epoxy resins, synthetic resins such as ABS resins, and glass. Among these, considering ease of handling, polycarbonate resin, polymethyl methacrylate resin and the like are preferable.

The dye layer 103 is formed by applying a dye solution prepared by dissolving an organic dye compound in a predetermined solvent onto the pregroove 101 formed in the recording area 15 of the substrate 10 by a spin coating method or the like. Can do. Examples of organic dye compounds include cyanine dyes, squarylium dyes, croconium dyes, azurenium dyes, triarylamine dyes, anthraquinone dyes, metal-containing azo dyes, dithiol metal complex dyes, indoaniline metal complexes. And system dyes, phthalocyanine dyes, naphthalocyanine dyes, and the like. These dyes may be used alone or in combination.
Examples of the solvent used for preparing the dye solution include ethyl cellosolve, methyl cellosolve, methanol, and tetrafluoropropanol. In addition to the organic dye compound, a quencher such as an antioxidant or a dithiol complex; a binder such as nitrocellulose, cellulose acetate, a ketone resin, an acrylic resin, polyvinyl butyral, or a polyolefin may be added to the dye layer 103. Good.

  The reflective layer 104 can be formed of a metal such as Au, Ag, Cu, Ni, Al, or Pt or an alloy material thereof by a vacuum deposition method, a sputtering method, an ion plating method, or the like. Among these, Ag and Al are desirable.

  The adhesive layer 18 can be formed by applying an adhesive on the reflective layer 104 by a method such as spin coating, gravure coating, spray coating, or roll coating. Examples of the adhesive include an ultraviolet curable acrylic resin, an ultraviolet curable epoxy resin, an ultraviolet curable adhesive, an epoxy adhesive, a silicone resin, a silicone adhesive, and a hot melt adhesive.

  The dummy substrate 16 is preferably formed using the same material as the substrate 10. By forming the dummy substrate 16 and the substrate 10 using the same material, it is possible to prevent the disc from warping when they are bonded together.

  The printed layer 17 is formed by applying an aqueous coating solution containing an ultraviolet curable resin on the dummy substrate 16 and then irradiating it with ultraviolet rays to cure it. Examples of the ultraviolet curable resin include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, phenoxyhydroxypropyl (meth) acrylate, chlorohydroxypropyl (meth) ) Acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycerin mono (meth) acrylate , Glycerin di (meth) acrylate, pentaerythritol (meth) acrylate, phenyl glycidyl ether ( Data) acrylate, dipentaerythritol penta (meth) acrylate, acrylate resins such di (meth) acrylate of bisphenol A epoxy resin.

  Examples of the crosslinkable monomer added to these resins include trimethylolpropane tri (meth) acrylate, acrylated isocyanurate, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol di (meth). Examples include acrylate, neopentyl glycol di (meth) acrylate, dicyclopentadiphenyl di (meth) acrylate, and pentaerythritol tetra (meth) acrylate.

  Examples of the radical initiator used for the curing reaction include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy 2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone, 4-phenoxy-2. 2, 2-dichloroacetophenone, acetophenone, 2-hydroxy-2-methylpropiophenone, propiophenone, 2-chloroanthraquinone, anthraquinone, 2,4-diethylthioxanthone, and the like.

The present embodiment will be described more specifically below based on examples. In addition, this invention is not limited to an Example.
(Example)
A polycarbonate resin was injection molded using a stamper to form a circular substrate having a thickness of 0.6 mm, an outer diameter of 120 mm, an inner diameter (center hole) of 15 mm, and a refractive index of 1.59.
In the molded substrate, a stamper pressing groove is formed at a position of φ21 mm from the center. A dummy groove having a shallower depth than the groove formed in the recording area is formed in the clamping area provided in the range of φ22 mm to φ34 mm from the center outside the stamper pressing groove. A pre-groove having a predetermined depth is formed in the recording area provided outside the clamping area.
The pregroove formed in the recording area has a track pitch of 0.74 μm, a depth of 160 nm, and a half-value width of 310 nm. The dummy groove formed in the clamping area has a track pitch of 0.74 μm, a depth of 100 nm, and a half-value width of 250 nm.

Next, an azo dye solution (concentration: 1.2% by weight) is applied by spin coating only from the center to the recording area on the pregroove formed on the substrate from the vicinity of φ36 mm to the outer periphery to form a dye layer. Film. The dye is accumulated in the pregroove after the dye layer is applied, and the shape of the depression on the surface of the dye layer is 100 nm in depth and 250 nm in half width.
Subsequently, an Ag alloy is sputtered so as to cover both the clamping area and the recording area in the range from φ22 mm to φ119 mm from the center of the substrate surface, and on the dye layer formed in the recording area and the dummy of the clamping area A reflective layer having a thickness of 100 nm is formed on the groove.
Since the reflection layer formed by sputtering maintains a uniform shape, the depth (Db) of the recess of the dummy groove provided with the reflection layer in the clamping area is the dummy groove before the reflection layer is provided. The full width at half maximum (Wb) is 250 nm, which is the same as the full width at half maximum before providing the reflective layer. Similarly, the depth (Da) of the dent on the surface of the dye layer provided with the reflective layer in the recording area is 100 nm, which is the same as the depth of the dent before the reflective layer is provided, and the half width (Wa) is also the same as that of the reflective layer. It is 250 nm which is the same as the half width before being provided.

Subsequently, an ultraviolet curable resin was applied so as to have a thickness of 10 μm so as to cover the reflective layer formed in the clamping area and the recording area by spin coating, thereby forming an adhesive layer.
Next, injection molding was performed using a polycarbonate resin to prepare a dummy substrate having grooves having the same shape as the above-described substrate pre-groove and dummy groove. The prepared dummy substrate has a thickness of 0.6 mm.
Subsequently, the prepared dummy substrate was placed on the adhesive layer such that the groove formed on the dummy substrate was directed to the adhesive layer provided on the substrate. Next, the superposed dummy substrate and the substrate were rotated at a high speed to remove excess UV curable resin. Next, an ultraviolet curable resin was solidified by ultraviolet irradiation to prepare an optical information recording medium in which a substrate having a recording layer and a dummy substrate having no recording layer were bonded together.
Since the refractive index of the cured UV curable resin is approximately equal to the refractive index of the dummy substrate made of polycarbonate resin, the thickness of the dummy substrate is uniform even if grooves are formed in the dummy substrate, and the light reflection It does not affect.

Next, a white protective layer is formed on the other surface (label surface side) where the groove of the dummy substrate is not formed by screen printing, knife coat printing, spin coating, or the like in a range outside φ21 mm from the center. Formed.
On the other hand, polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd .: trade name “EG-05”, saponification degree 86.5-89.0%) 14 parts, polyoxyethylene (400) diacrylate (manufactured by Kyoeisha Chemical Co., Ltd .: 5.7 parts of a trade name “Light Acrylate 9EG-A”), 0.3 part of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd .: trade name “IRGACURE2959”), and 80 parts of water. An aqueous coating solution was prepared.
Next, an aqueous coating solution prepared in advance by spin coating is applied onto a white protective layer formed on a dummy substrate, and then cured by irradiating with 500 mJ / cm ² of ultraviolet rays to form an ink receiving layer having a thickness of 20 μm. Formed. The white protective layer and the ink receiving layer described above were combined to form a printing layer. The printing layer is provided on the entire label surface of the dummy substrate so as to cover the clamping area of the optical information recording medium. The spin coating method was performed by dropping about 10 ml of an aqueous coating solution onto the inner periphery of the white protective layer, coating the entire coated surface at a rotational speed of 1,000 rpm, and subsequently setting the rotational speed to 2,000 rpm. It increased and the aqueous coating liquid was shaken off.

An image was printed on the printed layer on the dummy substrate thus prepared by an inkjet printer, and the printed image was visually observed from the label surface side. As a result of observation, the boundary between the image printed in the recording area and the image printed in the clamping area was not observed, and the problem that the image printed on the printing layer appeared to have a boundary was solved.
In addition, the recording layer is not formed in the dummy groove portion formed in the clamping area of the substrate, and the groove is also formed in the portion corresponding to the clamping area of the dummy substrate. When the dummy substrate is attached via the adhesive layer, the surface area of the adhesive layer is improved, thereby improving the adhesive strength between the substrate and the dummy substrate.

In this embodiment, when the reflective layer is provided on the substrate, the half width (Wb) of the dummy groove in the clamping area and the depression on the surface of the dye layer where the reflective layer is laminated on the pre-groove in the recording area. However, the present invention is not limited to this.
That is, when these half-value widths are different, the ratio between the track pitch and the half-value width can be adjusted by appropriately changing the track pitch of the dummy grooves formed in the clamping area. For example, it is possible to adjust so as to maintain a relationship of (Wa / track pitch a) ≈ (Wb / track pitch b). By adjusting this ratio, the reflection state of light when the label surface is visually observed can be made good.

It is a figure for demonstrating the optical information recording medium with which embodiment of this invention is applied. It is sectional drawing for demonstrating the vicinity of the clamping area of an optical information recording medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 11 ... Center hole, 12 ... Stamper pressing groove, 13 ... Stack rib, 14 ... Clamping area, 15 ... Recording area, 16 ... Dummy board, 17 ... Printed layer, 18 ... Adhesive layer, 100 ... Light Information recording medium, 101 ... pre-groove, 102 ... dummy groove

Claims (2)

A dummy substrate having a printed layer;
A substrate for recording and reproduction bonded with the dummy substrate through an adhesive layer,
The recording / reproducing substrate is:
A recording area formed with a tracking pre-groove in which a recording layer containing an organic dye and a reflective layer are laminated;
A clamping area provided on the inner peripheral side of the recording area and formed with a non-recording / reproducing dummy groove on which a reflective layer is laminated,
The groove shape of the dummy groove in the clamping area is
The groove depth of the dummy groove after the reflective layer is laminated on the dummy groove and the groove depth of the pregroove after the recording layer and the reflective layer are laminated on the pregroove of the recording area are equal. The optical information recording medium is characterized in that the groove depth of the dummy groove is shallower than the groove depth of the pre-groove. The printing layer of the dummy substrate, the a images printed on a portion corresponding to the clamping area of the substrate for the recording reproduction in the printing layer, corresponding to the recording area of the substrate for the recording and reproduction The difference between the contrast of the image printed on the portion corresponding to the clamping area and the contrast of the image printed on the portion corresponding to the recording area is determined so that the boundary between the image printed on the portion to be printed is not observed. The optical information recording medium according to claim 1, wherein the optical information recording medium is eliminated .

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