The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 1999
Filed:
Jan. 27, 1997
Hiroaki Miwa, Fujisawa, JP;
Ryoichi Sudo, Yokosuka, JP;
Tetsuo Tajima, Fujisawa, JP;
Eiji Koyama, Tsuchiura, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Maxell, Ltd., Tokyo, JP;
Abstract
The object of the present invention is to provide an optical disc and a method of manufacturing thereof 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 spcifications 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<2 G 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.