Diffraction optical element, molding die for the optical element and manufacturing method thereof
US7911921B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2008 |
| Grant date | Mar 22, 2011 |
| Priority date | — |
| Expiry date | Oct 12, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0018
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A diffraction optical element is provided to reduce harmful lights and also suppress deterioration in the optical characteristics of the element. The diffraction optical element 22 is formed with a plurality of diffraction gratings 17′, 18′, 19′ and 20′. From these diffraction gratings, there are selected the diffraction gratings 18′, 19′ and 20′ whose groove apex angles are less than a predetermined angle. The diffraction gratings 18′, 19′ and 20′ has chamfer surfaces 18c′, 19c′ and 20c′ formed on the lower side of respective slanted surfaces 18a′, 19a′ and 20a′. The chamfer surfaces 18c′, 19c′ and 20c′ are slanted to the slanted surfaces 18a′, 19a′ and 20a′, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.