Directional display apparatus
US12038649B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 2021 |
| Grant date | Jul 16, 2024 |
| Priority date | — |
| Expiry date | Jul 19, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/62
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A switchable privacy display comprises a spatial light modulator, and switchable liquid crystal retarder arranged between crossed quarter-wave plates and polarisers. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without loss, whereas off-axis light has reduced luminance to reduce the visibility of the display to off-axis snoopers. The display may be rotated to achieve privacy operation in landscape and portrait orientations. Further, display reflectivity may be reduced for on-axis reflections of ambient light, while reflectivity may be increased for off-axis light to achieve increased visual security. In a public mode of operation, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified. The display may also be operated to switch between day-time and night-time operation, for example for use in an automotive environment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.