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:
Mar. 04, 1997
Filed:
Sep. 07, 1994
Tamotsu Ito, Ayase, JP;
Hiroshi Banno, Koshigaya, JP;
Ryuichi Koike, Yokohama, JP;
Takashi Takeuchi, Fujisawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A CD-ROM is provided with an area for forming a character/graphic pattern. The character/graphic pattern is formed in such a way that data, which generate on the CD-ROM two sorts of pit patterns having average reflectances different from each other to a perceptible extent, are respectively recorded inside and outside the character/graphic pattern. Unless an illegal copy disc is produced by duplicating the legal original disc of the CD-ROM at a very high precision, the character/graphic pattern of the copy disc is invisibly deformed by the discrepancy between the arrangements of the pit patterns of the copy disc and the original disc.