Projection type display apparatus
US6062694A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1997 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Dec 18, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7441
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a projection type display apparatus which utilizes a polarizing beam splitter and/or a color separating/combining optical system, each being constituted by an optically transparent material block having a specific characteristic, thereby being capable of securing optically stable performances against influences of various thermal and external stresses and suppressing image quality deterioration to a low level. In particular, in this projection type display apparatus, the polarizing beam splitter used for a polarized light separating optical system and analyzing optical system, and/or an optical member servicing as a color separating/combining optical system are constituted by an optically transparent material block in which a wavelength where the absolute value of a photoelastic constant becomes a minimum level exists in a wavelength range of a blue light component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.