Projection-display apparatus
US6141151A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1999 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Jul 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7441
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus are disclosed that provide a high-luminance projected image with no color shading or uneven contrast. Light from a light source undergoes color separation by passing through a color-separation optical system (e.g., a cross-dichroic mirror or cross-dichroic prism). The light from the light source can also be split into first and second polarized lights by passage through, e.g., a first polarized-light beamsplitter (PBS). Each color-separated light is modulated by a respective color-signal light valve and undergoes color combining by, e.g., a cross-dichroic prism. The second polarized light, if formed, is modulated by a luminance-signal light valve, undergoes color combining and polarized-light combining by, e.g., a second PBS, and is projected by a projection lens (that comprises an aperture stop). The PBSs, cross-dichroic mirrors, and cross-dichroic prisms are situated where principal rays (defined by the aperture stop) are parallel to the optical axis. The first PBS (if present) and color-separation optical system are preferably arranged between a front illumination lens group and a rear illumination lens group both comprising an illumination relay optical system telecen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.