Illumination apparatus and projection type display apparatus
US6461001B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2001 |
| Grant date | Oct 8, 2002 |
| Priority date | — |
| Expiry date | Apr 23, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/005
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illumination apparatus and a projection type display apparatus of lower cost are provided, in which extra-axial aberrations, especially distortion and lateral aberration, are favorably corrected, and the dimensional margin of illumination is suppressed to enhance the utilization factor of light. The illumination apparatus includes a first group of lenses which includes a meniscus lens having a positive refracting power, a second group of lenses which includes first lens means having a negative refracting power and second lens means having a positive refracting power, and lens means whose surface immediately before a surface to-be-illuminated is a plane surface, whereby an illuminating light beam is caused to exit in a telecentric state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.