Phase plate technology for laser marking of magnetic discs
US5828491A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1996 |
| Grant date | Oct 27, 1998 |
| Priority date | — |
| Expiry date | Dec 20, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/1871
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An advanced design for a phase plate enables the distribution of spots in arbitrarily shaped patterns with very high uniformity and with a continuously or near-continuously varying phase pattern. A continuous phase pattern eliminates large phase jumps typically expected in a grating that provides arbitrary shapes. Large phase jumps increase scattered light outside of the desired pattern, reduce efficiency and can make the grating difficult to manufacture. When manufacturing capabilities preclude producing a fully continuous grating, the present design can be easily adapted to minimize manufacturing errors and maintain high efficiencies. This continuous grating is significantly more efficient than previously described Dammann gratings, offers much more flexibility in generating spot patterns and is easier to manufacture and replicate than a multi-level phase grating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.