Dichroic prism and projection display apparatus
US6072635A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1998 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Jul 9, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention provides a dichroic prism capable of reducing displacements of projection pixels of colors caused by chromatic aberration of magnification. A dichroic prism is formed in the shape of a quadrangular prism as a whole by joining four rectangular prisms together. A red reflecting dichroic plane and a blue reflecting dichroic plane intersect to form substantially an X shape along junction surfaces of the prisms. The red reflecting dichroic plane is convex-shaped by partly changing the thickness of an adhesive layer for connecting the rectangular prisms together. Accordingly, since a red beam can be guided to a projection optical system while being enlarged, it is possible to reduce a projection image of the red beam to be projected onto a projection plane via the projection optical system. This makes it possible to reduce relative displacements of projection pixels of color beams caused by chromatic aberration of magnification.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.