Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-11-18
2001-09-04
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S247000, C156S275500, C264S496000, C264S259000, C264S299000
Reexamination Certificate
active
06284084
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of manufacturing an optical disk such as CD-ROM or the like, and other information record carriers.
BACKGROUND ART
In the manufacture of an optical disk such as CD-ROM or the like and other information record carriers, conventionally, a stamper (mold) for producing a disk substrate is formed in a mastering step, a resin disk substrate is molded by an injection molding method using the stamper, and a recording film and reflecting film are deposited on the disk substrate.
In the disk substrate, an irregular shape must be formed in the recording surface thereof in correspondence with recording data. At present, an Ni master formed by Ni plating is used as the stamper having a surface shape for molding the irregular shape, and a molten resin is injected into a mold as the master by the injection molding method and solidified by cooling to form the disk substrate.
On the other hand, a method other than the above injection molding method, i.e., a so-called 2P method, has been proposed, which comprises coating an ultraviolet curable resin on the surface of the master or the resin disk substrate having transmissivity, bonding the master and the disk substrate with the ultraviolet curable resin therebetween, irradiating the disk substrate side with ultraviolet rays to cure the resin, and then separating the disk substrate from the master together with the cured resin layer (Japanese Unexamined Patent Publication Nos. 56-37836 and 1-180328, etc.) The 2P method has the advantage that since a liquid resin is used, duplication has excellent fidelity, and the stamper hardly deteriorates.
Japanese Unexamined Patent Publication No. 4-311833 discloses a method which uses a master formed by finely processing a semiconductor wafer of silicon or the like, or a quartz or glass surface by a known photolithographic process, in place of the master made of Ni.
In both the injection molding method and the 2P method, an optical disk and other information record carriers are required to have an amount of eccentricity with high precision. In order to reproduce a micro mark on the disk substrate, it is necessary to converge a light beam on the mark and irradiate the mark with the light beam. With the disk substrate having high eccentricity, a high degree of precession of the rotational shaft of a drive, or the like, deviation occurs in the tracks in the radial direction of the disk with rotation, and thus the laser spot is deviated from the tracks and crosses many tracks, thereby making correct recording and reproduction impossible. The amount of eccentricity of the disk substrate is determined by the position deviation between the master and the disk substrate during molding or transfer of information of the master surface. In order to suppress eccentricity, the dimensions of the disk substrate must be precisely controlled in molding. For a master such as the Ni master, which can easily be processed, a reference hole is formed by press working so that molding is carried out on the basis of the reference hole to decrease eccentricity. On the other hand, in a master made of silicone, quartz or glass, which is processed with difficulties, the processing precision deteriorates, and thus the eccentricity of the disk substrate cannot be easily decreased. There is also the problem of the high possibility of breaking the master due to the stress applied in processing. Therefore, under present conditions, the technique of finely processing semiconductors cannot be effectively utilized, and it is difficult to attempt to increase the recording density of the duplicated optical disk.
Accordingly, an object of the present invention is to solve the above problems, and realize manufacture of an information record carrier which is capable of improving the productivity of an optical disk and other information record carriers, and increasing the recording density thereof. Particularly, an object of the present invention is to provide a method of manufacturing an information record carrier with high productivity, which comprises coating a photosetting resin or a thermosetting resin on a substrate or a master, bonding the substrate and the master, and curing the photosetting resin or thermosetting resin to transfer the information of the master to the substrate.
SUMMARY OF THE INVENTION
In order to achieve the object, the present invention provides a method of manufacturing an information recording medium comprising the steps of coating a curable resin on a master or a disk substrate of an information recording medium, and pressing the substrate and the master, wherein one of the disk substrate and the master has a projection, and the other has a recess or hole which can be engaged with the projection so that pressing is carried out by engaging the projection and the recess or hole. The master has a pattern for permitting recording of information on the information recording medium. In the pressing step, the pattern is transferred to the information recording medium. The pressing step represents the step of pressing one of the master and the substrate on the other. The present invention facilitates alignment between the master and the substrate in the pressing step. With the projection and the recess or the like formed at a position and a height with high precision, it is possible to manufacture the information recording medium with less eccentricity.
A method of manufacturing an information record carrier of the present invention comprises the steps of coating a photosetting resin or thermosetting resin on a substrate or a master, bonding the substrate and the master, and curing the photosetting resin or thermosetting resin to transfer the information of the master to the substrate, wherein a projection is provided on the surface of the master.
In the method of manufacturing an information record carrier of the present invention, the projection is provided by bonding it to the surface of the master with an adhesive.
In the method of manufacturing an information record carrier of the present invention, the adhesive is a photosetting resin, a thermosetting resin, or an instantaneous adhesive.
In the method of manufacturing an information record carrier of the present invention, the projection is provided by bonding it to the surface of the master using magnetic force.
A method of manufacturing an information record carrier of the present invention comprises the steps of coating a photosetting resin or thermosetting resin on a substrate or a master, bonding the substrate and the master, and curing the photosetting resin or thermosetting resin to transfer the information of the master to the substrate, wherein a hole or recess is provided in the master.
In the method of manufacturing an information record carrier of the present invention, the hole or recess is provided by laser processing.
In the method of manufacturing an information record carrier of the present invention, as the laser, an excimer laser, a YAG laser, a CO
2
laser or a semiconductor laser is used.
In the method of manufacturing an information record carrier of the present invention, the hole or recess is provided by discharge processing.
In the method of manufacturing an information record carrier of the present invention, the hole or recess is provided by cutting.
In the method of manufacturing an information record carrier of the present invention, the hole or recess is provided by dry etching or wet etching.
In the method of manufacturing an information record carrier of the present invention, the master is made of silicon, quartz or glass.
By providing the projection on the surface of the master, alignment between the master and the substrate can be easily and precisely performed, thereby permitting manufacture of an information record carrier with less eccentricity and good productivity. Since the eccentricity is decreased, the manufacturing margin is widened, and the excellent effect of achieving higher recording density is exhibited.
REFERENCES:
patent: 5273598 (1993-12-01), Higasihara et al.
Nebashi Satoshi
Nishikawa Takao
Takakuwa Atsushi
Ball Michael W.
Harness & Dickey & Pierce P.L.C.
Seiko Epson Corporation
Tolin Michael A.
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