Polarizing prism for panel type liquid crystal display front projector and optical system using the polarizing prism
US5717472A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 21, 1996 |
| Grant date | Feb 10, 1998 |
| Priority date | — |
| Expiry date | Mar 21, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/283
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A polarizing element used for LCD projectors or LCD monitors, which includes a polarized beam separating and composing prism and either a twisted nematic (TN) liquid crystal or an 1/2 or 1/4 wavelength plate, thereby being capable of not only doubling the efficiency of the light source, but also obtaining a uniform intensity of light. The polarized beam separating and composing prism serves to transmit light beams being parallel to the polarization direction of the polarizer therethrough while shielding light beams being non-parallel to the polarization direction of the polarizer. With such a construction, it is possible to double the light efficiency while using the same light source. Where the polarizing element is applied to an optical system, certain elements of the optical system such as a reflecting mirror and condenser lens can have a reduced size which corresponds to 1/2 of the size of each LCD panel. Accordingly, it is possible to achieve an easy design and a uniformness in the intensity of composed light beams resulting in an increase in light efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.