Mold for cast molding substrate having preformat with information pits and method of using same
US5026510A · kind A · utility
7Cited by
6References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 10, 1989 |
| Grant date | Jun 25, 1991 |
| Priority date | — |
| Expiry date | Mar 10, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/81
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A cast mold and process for casting a substrate for an information recording medium has an uneven preformat pattern formed on the mold surface. The uneven preformat features a pattern corresponding to tracking grooves and information pits, each information pit portion has a size with a length b in the direction parallel to the pattern of the tracking groove of 2 to 15 .mu.m and a width a in the direction perpendicular thereto of 1 to 6 .mu.m and a height c of 300 to 3500 .ANG.. The pit pattern has a pitch which is 1.8-fold or more of pit length b.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.