Multilayer optical disc and method of making same
US5756265A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1996 |
| Grant date | May 26, 1998 |
| Priority date | — |
| Expiry date | Jun 6, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of making a multilayer optical disc of a type formed by laminating a plurality of signal layers each having a spiral or concentric pattern of a series of pits so that information can be read by irradiating any one of the signal layers with a playback laser from a surface of a substrate of the optical disc and reading waveforms reproduced therefrom. A master disc having a pit pattern formed thereon by exposing to a modulated exposure light pulse train is prepared for each of signal recorded layers. Based on this master disc, a mold is then prepared having a pit pattern which is a replica of the pit pattern on the master disc. Using the molds, respective replicas are formed and bonded together in face-to-face relation to thereby provide the multilayer optical disc. The series of pits on each signal layers in the master disc has a pit width or a pit length so chosen as to permit a signal reproduced from each signal layer to represent a waveform substantially identical with that of a signal which has been recorded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.