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US 5,686,227 AGranted
Optical reproduction apparatus
AssigneesHitachi, Ltd., Hitachi Maxell, Ltd.
InventorsHiroaki Miwa, Ryoichi Sudo, Tetsuo Tajima, Eiji Koyama
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AssigneesHitachi, Ltd., Hitachi Maxell, Ltd.
InventorsHiroaki Miwa, Ryoichi Sudo, Tetsuo Tajima, Eiji Koyama
Estimating the term…
The object of the present invention is to provide an optical disc, a method of manufacturing thereof and an optical reproduction apparatus including the same wherein defects and deterioration in the optical disc are minimized at the time of manufacture, during operation and storage thereof as well. The invention conceives an optical disc suitable for accomplishing the above object through specifications such as providing a cross-sectional structure thereof comprising a pair of transparent substrates each provided with at least one layer of a recording film formed on the surface of information patterns thereof, with the pair being bonded and laminated with an adhesive, and further providing an instantaneous axial acceleration <2G measured at room temperatures, a skew angle <5 mrad measured at room temperatures, and a skew angle <5 mrad measured after being left for one hour as heated to 80.degree. C. (otherwise, a shear mass <20 .mu.m measured after being left for one hour as heated to 80.degree. C.), and still further by utilizing a reaction adhesive the hardness of which after cure is between A30 and A80 in Shore hardness. On the other hand, preferred methods of manufacturing optical discs suitable for implementing the object of the invention were set forth, which utilize reaction adhesives having a Shore hardness after cure between A30 and A80.
An optical reproduction apparatus having an optical disc and an optical head, said optical disc having a cross-sectional structure comprising a pair of transparent substrates each having at least one layer of a recording film formed on a surface of information patterns thereof and the pair being bonded and laminated with an adhesive, wherein said optical disc is characterized by having an instantaneous axial acceleration <2G measured at room temperature, a skew angle <5 mrad measured at room temperature and a skew angle <5 mrad measured at room temperature after being left for one hour as heated to 80.degree. C.
An optical reproduction apparatus having an optical disc and an optical head, said optical disc having a cross-sectional structure comprising a pair of transparent substrates each having at least one layer of a recording film formed on a surface of information patterns thereof and the pair being bonded and laminated with an adhesive, wherein said optical disc is characterized by having an instantaneous axial acceleration <2 g measured at room temperature, a skew angle <5 mrad measured at room temperature and a shear mass <20 .mu.m measured at room temperature after being left for one hour as heated to 80.degree. C.
An optical reproduction apparatus having an optical disc and an optical head, said optical disc having a cross-sectional structure comprising a pair of transparent substrates each having at least one layer of a recording film formed on a surface of information patterns thereof and the pair being bonded and laminated with an adhesive, wherein said adhesive is characterized by being a reaction adhesive having a hardness after cure between A 30 and A 80 in Shore hardness.
An optical reproduction apparatus having an optical disc and an optical head, said optical disc comprising a pair of replica substrates, each of which comprises a transparent substrate having an information surface with information patterns formed in said information surface and at least one recording film overlying said information surface of the transparent substrate;
Dependencies are inferred from the claim text.