JP3977711B2 - Optical recording medium manufacturing method and manufacturing apparatus - Google Patents

Description

【００７０】
以上の測定結果を表１にまとめて示す。表１において、Ｒ−Ｓｋｅｗ (deg.) はディスク半径方向の反り角（°）を表し、Ｔ−Ｓｋｅｗ (deg.) はディスク円周方向の反り角（°）を表す。なお、測定機のレーザーヘッドにディスクの光透過層側が向くようにして、反り角を測定した。反りが光透過層側に凹の場合はプラス、逆の場合はマイナスの数値で表す。
ΔＲ−Ｓｋｅｗは、光透過層の形成前から光透過層の形成後における変化量であり、ΔＲ−Ｓｋｅｗ＝（光透過層形成後のＲ−Ｓｋｅｗ）−（光透過層形成前のＲ−Ｓｋｅｗ）である。同様に、ΔＴ−Ｓｋｅｗ＝（光透過層形成後のＴ−Ｓｋｅｗ）−（光透過層形成前のＴ−Ｓｋｅｗ）である。
【００７１】
なお、実施例１、２、及び比較例１における光透過層形成前のＲ−Ｓｋｅｗ値、Ｔ−Ｓｋｅｗ値は、同一の値となるべきであるが、現実に測定された値には僅かなバラツキが見られた。実施例３、４、及び比較例２においても同様に、僅かなバラツキが見られた。
【００７２】
表１より、実施例１〜４のいずれのディスクサンプルも、紫外線照射による樹脂の硬化収縮が非常に抑制され、光透過層の形成前後における反り角の変化量が小さく、機械特性に優れていた。特に、実施例４では、硬化収縮度合いがやや大きい樹脂を用いたにも係わらず、的確なアニール処理を行ったので、ディスクサンプルは機械特性に優れていた。
【００７３】
【発明の効果】
本発明によれば、０．１ｍｍ（１００μｍ）程度の厚さの光透過層を光硬化性樹脂を用いて形成し、機械特性に優れた光記録媒体を製造することができる。また、本発明によれば、前記方法に用いることのできる好適な光記録媒体の製造装置が提供される。
【図面の簡単な説明】
【図１】 本発明の方法により製造される光ディスクの一例の概略断面図である。
【図２】 本発明の方法により製造される光ディスクの他の一例の概略断面図である。
【図３】 本発明の製造方法に用いることのできる好適な製造装置の概略を示す一部切り欠き平面図である。
【符号の説明】
(1) ：光ディスク
(2) ：支持基体
(3) ：反射層
(4) ：誘電体層
(5) ：記録層
(6) ：誘電体層
(7) ：光透過層
(8) ：中心孔
(31)：スピンコーティング装置
(32)：第１の紫外線照射装置
(33)：アニール処理装置
(34)：第２の紫外線照射装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an optical recording medium, and more particularly to a method for manufacturing an optical recording medium having a light transmission layer formed of an energy ray curable resin on a recording layer. The present invention also relates to a suitable manufacturing apparatus that can be used in the method for manufacturing the optical recording medium.
[0002]
[Prior art]
In recent years, in optical recording media, it has been necessary to further increase the recording density for enormous information processing such as moving image information, and research and development has been actively conducted to further increase the recording capacity. .
[0003]
One of them is to shorten the wavelength of the recording / reproducing laser light, to increase the numerical aperture (NA) of the objective lens, and to reduce the spot diameter during recording / reproducing, as seen on DVDs, for example. Has been done. Actually, in a DVD, the recording / reproducing wavelength λ is changed from 780 nm to 650 nm of the CD, and the numerical aperture (NA) is changed from 0.45 to 0.6 of the CD, so that the recording capacity (6. 7GB / surface).
[0004]
However, various problems arise due to such high NA. For example, an allowable amount of aberration caused by an angle at which the disk surface deviates from the optical axis of the optical pickup, that is, a so-called tilt angle, becomes small. Here, assuming that the wavelength of the recording / reproducing laser beam is λ and the thickness of the substrate is t, the tolerance of the tilt of the optical recording medium with respect to the optical system, the so-called tilt margin M, is determined by the numerical aperture NA. That is, the tilt margin M is λ / {t × (NA)^Three}. In order to ensure the tilt margin M, it is necessary to reduce the thickness t of the substrate.
[0005]
Therefore, in the DVD, the thickness of the substrate is about half (about 0.6 mm) of the thickness of the conventional CD substrate (about 1.2 mm), thereby ensuring a tilt margin.
[0006]
Recently, in order to record a high-quality moving image for a long time, the wavelength λ of the recording / reproducing laser beam is further shortened to about 400 nm and the numerical aperture (NA) is increased to 0.85, which is four times that of DVD. Development of a system that attempts to achieve a high recording capacity (> 20 GB / surface), which is the above recording capacity, has been underway.
[0007]
In this system, recording / reproducing light is irradiated not through the substrate side but through a light transmission layer set to a thickness of about 0.1 mm. An optical recording medium having such a light transmission layer is described in, for example, Japanese Patent Laid-Open No. 10-289489, and the medium described in the same publication has a light transmission layer made of a photocurable resin.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-289489
[0009]
[Problems to be solved by the invention]
On the other hand, in conventional optical recording media such as CDs and DVDs, an energy ray curable resin is used for the protective layer, and there is a problem of an increase in warpage due to the curing shrinkage of the resin. Various studies have been conducted. However, the coating thickness of the energy ray curable resin of the protective layer is about 2 μm to 20 μm, and the study of a thick film thickness exceeding this is not sufficient.
[0010]
That is, when a light transmission layer having a thickness of about 0.1 mm (100 μm) is formed from an energy ray curable resin, it is considered difficult to solve the problem of curing shrinkage only by improving the resin material. .
[0011]
Accordingly, an object of the present invention is to provide a method for producing an optical recording medium having excellent mechanical properties by forming a light transmission layer using an energy ray curable resin.
Another object of the present invention is to provide a suitable optical recording medium manufacturing apparatus that can be used in the above method.
[0012]
[Means for Solving the Problems]
As a result of intensive studies, the inventors of the present invention use an energy ray curable resin having a relatively small degree of curing shrinkage to cure the resin stepwise to disperse the stress generated by the curing shrinkage and to accumulate the stress on the disk. As a result, the present inventors have found that an optical recording medium excellent in mechanical properties can be obtained in which the deformation of the disk is extremely suppressed, and the present invention has been achieved.
The present inventors have further found that an optical information medium having further excellent mechanical characteristics can be obtained by once releasing the stress accumulated in the disk by annealing and then curing it again.
[0013]
  The present invention is a method for producing an optical recording medium having at least one recording layer and a light transmission layer on a recording layer on a support substrate, and an energy ray curable resin layer is provided on the recording layer, This resin layer is irradiated with energy rays at least twice.In addition, an annealing process (thermal relaxation process) is performed between any one of the energy beam irradiations and the next energy beam irradiation.Thus, a method for producing an optical recording medium, characterized in that a light transmission layer is formed.
[0014]
The present invention is the above-described method for manufacturing an optical recording medium, wherein the integrated light quantity of each time of energy beam irradiation is increased stepwise between each time.
The present invention is the above-described method for producing an optical recording medium, wherein the energy rays are ultraviolet rays.
[0015]
BookThe present invention is the above-described method for manufacturing an optical recording medium, wherein the annealing process is performed at a temperature of 60 ° C. or higher.
[0016]
The present invention is the method for manufacturing an optical recording medium, wherein the light transmission layer has a thickness of 20 to 200 μm.
[0017]
The present invention also provides an application means for applying an energy beam curable resin on a support substrate to provide an energy beam curable resin layer, and a semi-cured resin layer by irradiating the energy beam curable resin layer with an energy beam. A first energy ray irradiating means, an annealing treatment means for heating the semi-cured resin layer, and the annealed semi-cured resin layer is irradiated with energy rays to form a fully cured resin layer. An apparatus for manufacturing an optical recording medium, comprising: a second energy beam irradiation unit.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
A method for manufacturing an optical recording medium (hereinafter abbreviated as an optical disk) will be described with reference to the drawings. Hereinafter, a phase change type optical disc will be described as an example. However, the present invention is not limited to this, and can be widely applied regardless of the type of recording layer, such as a read-only optical disc and an optical disc that can be recorded only once.
[0019]
FIG. 1 is a schematic cross-sectional view of an example of an optical disk manufactured by the method of the present invention. In FIG. 1, an optical disk (1) has a reflective layer (3), a dielectric layer (4), a recording layer on the surface of a support base (2) on which fine irregularities such as information pits and pregrooves are formed. The layer (5) and the dielectric layer (6) are provided in this order, the light transmission layer (7) is provided on the dielectric layer (6), and the center hole (8) is provided. The optical disk (1) is used so that laser light for recording or reproduction enters through the light transmission layer (7).
[0020]
The support substrate (2) has a thickness of 0.3 to 1.6 mm, preferably 0.5 to 1.3 mm, and has information pits and pregrooves on the surface on which the recording layer (5) is formed. Etc. are formed.
The support substrate (2) does not need to be optically transparent, and various plastic materials such as polycarbonate resins, acrylic resins such as polymethyl methacrylate (PMMA), polyolefin resins, and the like can be used. When such a material that is easily bent is used, the present invention is particularly effective because the occurrence of warpage can be suppressed. However, glass, ceramics, metal or the like may be used. In the case of using a plastic material, the concavo-convex pattern is often created by injection molding, and in the case of other than the plastic material, it is formed by a photopolymer method (2P method).
[0021]
On the support substrate (2), the reflective layer (3) is usually formed by sputtering. As a material for the reflective layer, a metal element, a metalloid element, a semiconductor element, or a compound thereof is used alone or in combination. Specifically, for example, a known reflective layer material such as Au, Ag, Cu, Al, or Pd may be selected. The reflective layer is preferably formed as a thin film having a thickness of 20 to 200 nm.
[0022]
The dielectric layer (4), the recording layer (5), and the dielectric layer (6) are sputtered in this order on the reflective layer (3) or directly on the support substrate (2) when there is no reflective layer. It is formed by.
[0023]
The recording layer (5) is reversibly changed between a crystalline state and an amorphous state by laser light irradiation, and is formed of a material having different optical characteristics between the two states. For example, Ge—Sb—Te, In—Sb—Te, Sn—Se—Te, Ge—Te—Sn, In—Se—Tl, In—Sb—Te, and the like can be given. Further, these materials contain a trace amount of at least one of metals selected from Co, Pt, Pd, Au, Ag, Ir, Nb, Ta, V, W, Ti, Cr, Zr, Bi, In, and the like. It may be added, or a reducing gas such as nitrogen may be added in a trace amount.
The thickness of the recording layer (5) is not particularly limited and is, for example, about 3 to 50 nm.
[0024]
The dielectric layer (4) and the dielectric layer (6) are formed on both sides of the upper and lower sides of the recording layer (5). The dielectric layer (4) and the dielectric layer (6) have a function as an interference layer for adjusting optical characteristics as well as mechanical and chemical protection functions of the recording layer (5). Each of the dielectric layer (4) and the dielectric layer (6) may be composed of a single layer or a plurality of layers.
[0025]
The dielectric layer (4) and the dielectric layer (6) are selected from Si, Zn, Al, Ta, Ti, Co, Zr, Pb, Ag, Zn, Sn, Ca, Ce, V, Cu, Fe, and Mg. It is preferably formed from an oxide, a nitride, a sulfide, a fluoride, or a composite thereof containing at least one of the metals. The extinction coefficient k of the dielectric layer (4) and the dielectric layer (6) is preferably 0.1 or less.
[0026]
The thickness of the dielectric layer (4) is not particularly limited, and is preferably about 20 to 150 nm, for example. The thickness of the dielectric layer (6) is not particularly limited, and is preferably about 20 to 200 nm, for example. By selecting the thickness of the dielectric layers (4) and (6) within such a range, the reflection can be adjusted.
[0027]
A light transmission layer (7) is formed on the dielectric layer (6) using an energy ray curable resin.
[0028]
Energy ray curable resin is selected from UV curable resin and electron beam curable resin, provided that it is optically transparent, has little optical absorption and reflection in the laser wavelength range used, and has low birefringence. To do.
[0029]
Specifically, it is preferably composed of an ultraviolet (electron beam) curable compound or a composition for polymerization thereof. Examples of such compounds include ester compounds of acrylic acid and methacrylic acid, acrylic double bonds such as epoxy acrylate and urethane acrylate, allyl double bonds such as diallyl phthalate, and unsaturated double bonds such as maleic acid derivatives. Mention may be made of monomers, oligomers, polymers and the like containing or introduced in the molecule a group which crosslinks or polymerizes upon irradiation with ultraviolet rays such as bonds. These are preferably polyfunctional, particularly trifunctional or more, and may be used alone or in combination of two or more.
[0030]
As the UV curable monomer, a compound having a molecular weight of less than 2000 is preferable, and as the oligomer, a molecular weight of 2000 to 10,000 is preferable. Examples of these include styrene, ethyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, 1,6-hexane glycol diacrylate, 1,6-hexane glycol dimethacrylate, and the like. Examples thereof include pentaerythritol tetra (meth) acrylate, pentaerythritol (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, and (meth) acrylate of a phenol ethylene oxide adduct. In addition, examples of the ultraviolet curable oligomer include oligoester acrylate and an acrylic modified product of urethane elastomer.
[0031]
Moreover, as an ultraviolet curable material, the composition containing an epoxy resin and a photocationic polymerization catalyst is also used suitably. As the epoxy resin, alicyclic epoxy resins are preferable, and those having two or more epoxy groups in the molecule are particularly preferable. Examples of alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexylmethyl) adipate, bis- (3,4-epoxycyclohexyl) adipate, One or more of 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (2,3-epoxycyclopentyl) ether, vinylcyclohexene dioxide and the like are preferable. . Although there is no restriction | limiting in particular in the epoxy equivalent of an alicyclic epoxy resin, Since favorable sclerosis | hardenability is acquired, it is preferable that it is 60-300, especially 100-200.
[0032]
Any known photocationic polymerization catalyst may be used without any particular limitation. For example, one or more metal fluoroborate and boron trifluoride complexes, bis (perfluoroalkylsulfonyl) methane metal salts, aryldiazonium compounds, 6A group aromatic onium salts, 5A group aromatic onium salts, Dicarbonyl chelate, thiopyrylium salt of group 3A-5A element, group 6A element having MF6 anion (where M is P, As or Sb), triarylsulfonium complex salt, aromatic iodonium complex salt, aromatic sulfonium complex salt, etc. are used. In particular, it is preferable to use one or more of polyarylsulfonium complex salts, aromatic sulfonium salts or iodonium salts of halogen-containing complex ions, aromatic onium salts of group 3A elements, group 5A elements and group 6A elements.
[0033]
As a radiation curable resin used for a light transmissive layer, what has a viscosity (25 degreeC) of 1,000-10,000cp is preferable.
[0034]
In the present invention, an energy ray curable resin is applied on the dielectric layer (6) to provide an uncured energy ray curable resin layer. Application at this time may be performed by a spin coating method.
[0035]
Next, energy ray irradiation is performed in a plurality of times on the uncured energy ray-curable resin layer, and the resin is cured stepwise. That is, at least two irradiations of energy rays are performed: irradiation until the semi-cured state before complete curing and irradiation from the semi-cured state to the fully cured state. As energy rays, ultraviolet rays or electron beams are used depending on the resin used.
[0036]
The first energy beam irradiation is performed with an integrated light amount that leaves a tack on the surface of the resin layer, and the resin is in a semi-cured state. Although it differs depending on the resin material, it can be achieved by shortening the irradiation time or reducing the irradiation intensity as compared with the case of complete curing by one irradiation. Such energy beam irradiation before complete curing is performed once or twice or more. When performing irradiation twice or more before complete curing, the integrated light quantity of each energy ray irradiation is increased step by step between each time.
[0037]
Next, in order to finally completely cure the resin, the final energy beam irradiation is performed with an integrated light amount that is greater than any integrated light amount of each energy beam irradiation before complete curing, and the resin is completely cured. Put it in a state. This can be achieved by lengthening the irradiation time or increasing the irradiation intensity compared to each irradiation before complete curing.
[0038]
The integrated light amount of each energy ray irradiation varies depending on the resin material, the thickness of the resin layer, and the like. For example, when performing the irradiation twice, the integrated light amount of the first energy ray irradiation is 5 to 300 mJ / cm.²Integrated light quantity of the second energy beam irradiation 500 to 5000 mJ / cm²To the extent.
[0039]
In this way, by curing the resin stepwise, it is possible to reduce the stress due to curing shrinkage that accumulates on the disk at a time, and finally the stress that accumulates on the disk is reduced. As a result, even if the thickness of the light transmission layer (7) is 20 μm or more and 200 μm or less, particularly 70 μm or more and 150 μm or less, and more particularly 75 μm or more and 150 μm or less, a disk having excellent mechanical properties is produced. Can do.
[0040]
  Further, the stress due to curing shrinkage is maximized at the moment when the resin is cured, and is relieved with the passage of time. For this reason, it is possible to further reduce the stress accumulated by curing shrinkage by releasing the stress accumulated in the disk and then performing the next curing. However, since it is not productive to spend time until the stress is released in a semi-cured state, it is possible to release the stress in a short time by performing an annealing process, and then irradiate the energy ray again to be cured. That is, in the present invention,Any timeEnergy beam irradiation and the next of this irradiationTimesAn annealing process is performed between energy beam irradiationYeah. DWhen performing energy beam irradiation three or more times, annealing treatment is performed at the end of each irradiation, such as between the first irradiation and the second irradiation, and between the second irradiation and the third irradiation. It is preferable to perform the step from the viewpoint of releasing the curing shrinkage stress.
[0041]
The annealing temperature is preferably 60 ° C. or higher, and more preferably 80 ° C. or higher. By setting the annealing temperature to 80 ° C. or higher, the stress can be released more quickly and completely. Although the upper limit of the annealing temperature depends on the material of the supporting substrate to be used, it is preferably performed at a temperature that is at least 10 ° C. lower than the glass transition temperature Tg of a generally used material. Also, the annealing treatment time is preferably 1 to 5 minutes from the viewpoint of production efficiency, though it depends on the annealing treatment temperature.
By performing the annealing process in this way, a disk having further excellent mechanical characteristics can be produced.
[0042]
Further, in the present invention, an uncured energy beam curable resin layer having a thickness corresponding to a part of the target thickness of the light transmission layer (7) is formed, and the resin is semi-cured by performing energy beam irradiation. As a state, on the semi-cured resin layer, a layer of the same resin having a thickness corresponding to the remainder of the target thickness is formed by overcoating, and then energy beam irradiation is performed to form a semi-cured resin layer. It is possible to completely cure the uncured resin layer. If it does in this way, mixing will occur in the interface of two resin layers, and it can raise the adhesiveness between both resin layers.
[0043]
As described above, the manufacturing method of the present invention has been described using the optical disk shown in FIG. 1 as an example. However, the manufacturing method of the present invention is also applied to the so-called single-sided, double-layered optical disk shown in FIG.
[0044]
In FIG. 2, the optical disk (11) has a second recording layer dielectric layer (14) and a second recording layer on the surface of the support substrate (12) on which fine irregularities such as information pits and pregrooves are formed. Recording layer (layer 1) (15), dielectric layer for second recording layer (16), spacer layer (21), dielectric layer for first recording layer (18), first recording layer (layer 0) (19 ), A first recording layer dielectric layer (20) in this order, a light transmission layer (17) on the dielectric layer (20), and a central hole (22). Although not shown, a reflective layer may be provided between the support base (12) and the dielectric layer (14) and between the spacer layer (21) and the dielectric layer (18). The optical disk (11) is used so that laser light for recording or reproduction enters through the light transmission layer (17).
[0045]
Next, a suitable manufacturing apparatus that can be used in the above-described optical recording medium manufacturing method of the present invention will be described with reference to FIG. FIG. 3 is a partially cutaway plan view showing an outline of a suitable manufacturing apparatus that can be used in the manufacturing method of the present invention.
[0046]
In FIG. 3, an optical recording medium manufacturing apparatus includes a spin coating apparatus (31) that applies an energy ray curable resin on a support substrate and provides an energy ray curable resin layer, and an energy ray curable resin layer on the energy ray curable resin layer. A first ultraviolet irradiation device (32) that irradiates and forms a semi-cured resin layer; an annealing treatment device (33) that heats the semi-cured resin layer; and the semi-cured resin that has been annealed. And a second ultraviolet irradiation device (34) for irradiating the layer with energy rays to form a completely cured resin layer.
[0047]
The spin coating apparatus (31) includes a disk feeder (41) for supplying a disk on which a light transmission layer is to be formed, a horizontal rotary table (42) for mounting and rotating the disk, and an energy beam curable resin on the disk surface. And a discharge nozzle (43) for dropping the liquid. The disk feeder (41) has a vacuum pad for adsorbing and holding the disk at the tip, and is capable of conveying and supplying the disk by vertical vertical movement and horizontal rotation movement of 90 degrees. The discharge nozzle (43) is attached to a horizontal arm (45) fixed to a vertically rotating shaft (44) that rotates reversibly, and rotates in the horizontal direction along with the rotation of the vertically rotating shaft (44). . In addition, the application liquid is supplied to the discharge nozzle (43) through the application liquid supply pipe (46), and the application liquid is dropped from the nozzle tip.
[0048]
The first ultraviolet irradiation device (32) includes a main body (51), an irradiation head (52) installed above a disk placed on the rotary table (42), a main body (51), and an irradiation head. And a connecting tube portion (53) for connecting (52). An ultra high pressure mercury lamp as an ultraviolet light source is installed in the main body (51). Further, a condensing / sending optical system is installed in the main body (51), so that the ultraviolet rays from the ultra-high pressure mercury lamp are condensed and sent out as an ultraviolet beam directed to the connecting tube portion (53). The The connecting cylinder part (53) is a cylinder and an integrator lens is incorporated therein, and the ultraviolet beam passes through the cylinder part (53) and enters the irradiation head (52). The irradiation head (52) has a built-in reflecting plate so that the ultraviolet beam incident from the cylindrical portion (53) can be bent 90 degrees and irradiated toward the lower disk.
[0049]
The annealing apparatus (33) transports the disk on the rotating table (42) of the annealing chamber (61) and the spin coating apparatus (31) to a predetermined position of the annealing chamber (61), and the disk after the annealing process. And a coat hand (65) transported to the second ultraviolet irradiation device (34) in the next step.
[0050]
The annealing chamber (61) includes a rotary table (62) and an appropriate number of infrared flat panel heaters (64) installed above the rotary table (62). The rotary table (62) is provided with twelve disc support portions (63) so that twelve discs can be placed in the vicinity of the outer periphery of the rotary table (62). In the example, it rotates intermittently counterclockwise. An appropriate device for rotation is provided below the rotary table (62).
[0051]
The coat hand (65) is rotatable about a vertical axis (65c) within a range of 120 degrees. The coat hand (65) is rotated 60 degrees clockwise from the state shown in FIG. 3, and one arm (65a) of the coat hand (65) is positioned on the disk on the rotary table (42). At this position, the disk on the rotary table (42) is picked up by a vacuum suction mechanism provided at the tip of the arm (65a). Thereafter, the coat hand (65) rotates 120 degrees counterclockwise, and the arm (65a) is positioned on a predetermined position of the rotary table (62), that is, on the disk support portion indicated by 63A. At this position, the vacuum suction of the disc is released and the disc is set on the disc support (63).
[0052]
Further, the other arm (65b) of the coat hand (65) is placed on the disk support portion indicated by 63A when the coat hand (65) is rotated 60 degrees clockwise from the state shown in FIG. Located in. At this position, the annealed disc on the disc support portion indicated as 63A is picked up by a vacuum suction mechanism provided at the tip of the arm (65b). Thereafter, when the coated hand (65) is rotated 120 degrees counterclockwise, the arm (65b) is indicated as 73A of the disk moving mechanism (73) of the second ultraviolet irradiation device (34) described below. Come to the position. At this position, the vacuum suction of the disk is released and the disk is set at a position indicated by 73A of the disk moving mechanism (73).
[0053]
The second ultraviolet irradiation device (34) includes an ultraviolet lamp (71) supported by a support member (72) as appropriate, a disk moving mechanism (73) that linearly moves the disk to the left, and a light transmission layer. A disc ejector (74) for ejecting the disc. Although details of the disk moving mechanism (73) are not shown, it is a known mechanism provided in a so-called conveyor type ultraviolet irradiation device. The disk is moved from the position of 73A to the position of 73B, and during this time, the ultraviolet light is irradiated to the disk from the ultraviolet lamp (71). The disc ejector (74) has the same mechanism as the disc feeder (41).
[0054]
In the present invention, first, a disc having at least one recording layer on which a light transmission layer is to be formed is placed on a rotary table (42) by a disc feeder (41) and vacuum-sucked. A predetermined amount of energy beam curable resin liquid is dropped from the tip of the discharge nozzle (43) onto the surface of the disk placed on the rotary table (42). At the time of dropping, the disk may be either stationary or rotating. Next, the disk is rotated at a high speed to form a resin layer having a uniform film thickness on the disk surface.
[0055]
The uncured resin layer is irradiated with ultraviolet rays for the first time from the irradiation head (52) to obtain a desired semi-cured state. At this time, the disc remains rotated.
[0056]
Stop the rotation of the disk, pick up the disk by one arm (65a) of the coat hand (65), and place it at a predetermined position on the rotary table (62) of the annealing apparatus (33), that is, 63A. Set to (63). In the illustrated example, the rotary table (62) is intermittently rotated 360 degrees counterclockwise in the illustrated example, while the disk is annealed in the annealing chamber (61) at a predetermined time and temperature. This time and temperature can be appropriately adjusted.
[0057]
The disk which has been annealed and returned to the position of 63A is picked up by the other arm (65b) of the coat hand (65) and indicated as 73A of the disk moving mechanism (73) of the second ultraviolet irradiation device (34). Set to the specified position. The disk is linearly moved from the position of 73A to the position of 73B, and during this time, the disk is irradiated with ultraviolet rays from the ultraviolet lamp (71) to be in a completely cured state. In this way, a light transmission layer is formed.
[0058]
In this apparatus, it is possible to perform two ultraviolet irradiations and an annealing process between these irradiations. In order to perform an annealing process between three or more ultraviolet irradiations and each of these irradiations, an annealing apparatus is further provided. And an ultraviolet irradiation device, or a series of processes of annealing and ultraviolet irradiation may be repeated using this device.
[0059]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.
[0060]
[Example 1](Reference example)
  An optical disc sample was prepared according to the following procedure.
  A reflective layer having a thickness of 100 nm made of an alloy containing Ag as a main component was formed on the surface of a disk-shaped support substrate (made of polycarbonate, diameter 120 mm, thickness 1.1 mm) on which pregrooves were formed. The depth of the groove was expressed as an optical path length at a wavelength λ = 405 nm, λ / 10, and a land / groove substrate having a recording track pitch of 0.3 μm was used.
[0061]
Subsequently, ZnS (80 mol%)-SiO2 is formed on the reflective layer surface.₂A dielectric layer having a thickness of 30 nm was formed by sputtering using a (20 mol%) target. Next, a recording layer having a thickness of 12 nm was formed on the surface of the dielectric layer by sputtering using an alloy target made of a phase change material. The composition of the recording layer was GeSbTe.
Next, ZnS (80 mol%)-SiO is formed on the surface of the recording layer.₂A dielectric layer having a thickness of 100 nm was formed by sputtering using a (20 mol%) target. With respect to the disk in this state, mechanical characteristics (a warp angle in the disk radial direction and a warp angle in the disk circumferential direction) were measured with a machine precision measuring machine DC-1010C manufactured by Cores Co., Ltd.
[0062]
After the measurement, an ultraviolet curable resin (curing shrinkage: 5.5%, viscosity: 5000 cP at 25 ° C.) mainly composed of urethane acrylate was applied to the upper dielectric layer surface by spin coating, and shaken off at 2000 rpm for 8 seconds. An uncured resin layer having a thickness of 100 μm was obtained.
[0063]
Ultraviolet rays are applied to the ultraviolet curable resin layer formed in this way, and the UV integrated light quantity is 140 mJ / cm.²And a semi-cured resin layer was obtained. After that, ultraviolet rays are applied to the resin layer, and the UV integrated light quantity is 3000 mJ / cm²The resin layer was completely cured to form a light transmission layer. The disk samples thus prepared were measured for mechanical properties (the warp angle in the disk radial direction and the warp angle in the disk circumferential direction) using the DC-1010C.
[0064]
[Example 2]
The same procedure as in Example 1 was performed until the uncured resin layer was formed. UV integrated light quantity 140mJ / cm²And a semi-cured resin layer was obtained. Next, an annealing treatment is performed at 60 ° C. for 3 minutes, and then ultraviolet rays are applied to the resin layer with a UV integrated light amount of 3000 mJ / cm²The resin layer was completely cured to form a light transmission layer. The disk sample thus prepared was measured for mechanical properties using the DC-1010C.
[0065]
[Comparative Example 1]
The same procedure as in Example 1 was performed until the uncured resin layer was formed. Without semi-curing the resin layer, UV light is applied to the resin layer with a UV integrated light amount of 3000 mJ / cm.²The resin layer was completely cured to form a light transmission layer. The disk sample thus prepared was measured for mechanical properties using the DC-1010C.
[0066]
[Example 3](Reference example)
  Except for using UV curable resin mainly composed of urethane acrylate, a resin having a slightly higher cure shrinkage than the resin used in Example 1 (curing shrinkage 5.9%, viscosity 5800 cP at 25 ° C.) was used. A disk sample was prepared in the same manner as in Example 1. The disk sample was measured for mechanical properties using the DC-1010C.
[0067]
[Example 4]
A disk sample was prepared in the same manner as in Example 2 except that the resin used in Example 3 was used as the ultraviolet curable resin and the annealing temperature was 80 ° C. The disk sample was measured for mechanical properties using the DC-1010C.
[0068]
[Comparative Example 2]
A disk sample was prepared in the same manner as in Comparative Example 1 except that the resin used in Example 3 was used as the ultraviolet curable resin. The disk sample was measured for mechanical properties using the DC-1010C.
[0069]
[Table 1]

[0070]
The above measurement results are summarized in Table 1. In Table 1, R-Skew (deg.) Represents the warp angle (°) in the disk radial direction, and T-Skew (deg.) Represents the warp angle (°) in the disk circumferential direction. The warp angle was measured such that the light transmission layer side of the disk was facing the laser head of the measuring machine. When the warp is concave on the light transmitting layer side, the value is plus, and when the warp is opposite, the value is minus.
ΔR-Skew is the amount of change after formation of the light transmission layer from before formation of the light transmission layer, and ΔR-Skew = (R-Skew after formation of the light transmission layer) − (R-Skew before formation of the light transmission layer). ). Similarly, ΔT-Skew = (T-Skew after formation of the light transmission layer) − (T-Skew before formation of the light transmission layer).
[0071]
It should be noted that the R-Skew value and T-Skew value before formation of the light transmission layer in Examples 1 and 2 and Comparative Example 1 should be the same value, but the values actually measured are a little. Variations were seen. Similarly, in Examples 3 and 4 and Comparative Example 2, slight variations were observed.
[0072]
From Table 1, in any of the disk samples of Examples 1 to 4, the curing shrinkage of the resin due to ultraviolet irradiation was greatly suppressed, the change amount of the warp angle before and after the formation of the light transmission layer was small, and the mechanical properties were excellent. . In particular, in Example 4, despite the use of a resin having a slightly high degree of cure shrinkage, an accurate annealing treatment was performed, so that the disk sample was excellent in mechanical properties.
[0073]
【The invention's effect】
According to the present invention, an optical recording medium having excellent mechanical properties can be manufactured by forming a light transmission layer having a thickness of about 0.1 mm (100 μm) using a photocurable resin. The present invention also provides a suitable optical recording medium manufacturing apparatus that can be used in the above method.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an example of an optical disk manufactured by the method of the present invention.
FIG. 2 is a schematic cross-sectional view of another example of an optical disc manufactured by the method of the present invention.
FIG. 3 is a partially cutaway plan view showing an outline of a suitable manufacturing apparatus that can be used in the manufacturing method of the present invention.
[Explanation of symbols]
(1): Optical disc
(2): Support base
(3): Reflective layer
(4): Dielectric layer
(5): Recording layer
(6): Dielectric layer
(7): Light transmission layer
(8): Center hole
(31): Spin coating equipment
(32): First ultraviolet irradiation device
(33): Annealing equipment
(34): Second ultraviolet irradiation device

Claims (6)

A method of manufacturing an optical recording medium having at least one recording layer and a light transmission layer on a recording layer on a support substrate, wherein an energy ray curable resin layer is provided on the recording layer, and the resin layer is provided on the resin layer. There row energy ray irradiation at least twice, and, during one round of the energy ray irradiation and subsequent rounds of the energy ray irradiation of the irradiation, by performing the annealing process (the annealing step) A method for producing an optical recording medium, comprising forming a light transmission layer.   The method of manufacturing an optical recording medium according to claim 1, wherein the integrated light quantity of each irradiation of energy rays is increased stepwise between each time.   The method for producing an optical recording medium according to claim 1, wherein the energy rays are ultraviolet rays. An annealing step at a temperature above 60 ° C., a manufacturing method of an optical recording medium according to any one of claims 1 to 3. The thickness of the light transmission layer is 20 to 200 [mu] m, a manufacturing method of an optical recording medium according to any one of claims 1 to 4. An application means for applying an energy ray curable resin on a support substrate and providing an energy ray curable resin layer;
A first energy ray irradiation means for irradiating the energy ray curable resin layer with an energy ray to form a semi-cured resin layer;
Annealing treatment means for heating the semi-cured resin layer;
An apparatus for manufacturing an optical recording medium, comprising: a second energy ray irradiating unit that irradiates the annealed semi-cured resin layer with energy rays to form a completely cured resin layer.

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