Invention Grant
US5608717A Information recording media and optical disc presenting a character or a
graphic pattern formed by specified pit patterns on data tracks
失效
信息记录介质和光盘，其呈现由数据轨道上的指定凹坑图案形成的字符或图形图形
- Patent Title: Information recording media and optical disc presenting a character or a graphic pattern formed by specified pit patterns on data tracks
- Patent Title (中): 信息记录介质和光盘，其呈现由数据轨道上的指定凹坑图案形成的字符或图形图形
-
Application No.: US301889Application Date: 1994-09-07
-
Publication No.: US5608717APublication Date: 1997-03-04
- Inventor: Tamotsu Ito , Hiroshi Banno , Ryuichi Koike , Takashi Takeuchi
- Applicant: Tamotsu Ito , Hiroshi Banno , Ryuichi Koike , Takashi Takeuchi
- Applicant Address: JPX Tokyo
- Assignee: Hitachi, Ltd.
- Current Assignee: Hitachi, Ltd.
- Current Assignee Address: JPX Tokyo
- Priority: JPX5-221687 19930907; JPX6-65224 19940401
- Main IPC: G11B7/005
- IPC: G11B7/005 ; G11B7/007 ; G11B7/24 ; G11B7/24094 ; G11B20/00 ; G11B23/28 ; G11B23/34 ; G11B23/38
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.
Public/Granted literature
- US4995939A Method and apparatus for determining the layer thickness of semiconductor layer structures Public/Granted day:1991-02-26
Information query
IPC分类:
