Liquid crystal structure with improved black state, and projector using same
US7057686B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 2004 |
| Grant date | Jun 6, 2006 |
| Priority date | — |
| Expiry date | Jul 23, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1396
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A liquid crystal (LC) lightvalve comprising a twisted nematic LC layer whose molecules are aligned with pixel edges at the mirror backplane, thereby providing improved contrast and efficiency, and reduced visibility of post spacers in black state. The present invention is directed to an LC structure wherein the backplane is rubbed in a direction rectilinear with pixel edges. The LC layer is given the same twist rotation and birefringence as in the conventional TN lightvalve. Polarization control is maintained by illuminating the lightvalve with light whose polarization is rotated by the twist angle relative to the x,y, pixel axes, and by collecting the orthogonally polarized component of the reflected light. The lightvalve top glass is thus rubbed in a direction which is rotated by the twist angle from the horizontal or vertical direction at which the backplane is rubbed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.