Reflective optical stack for privacy display
US10976578B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 2019 |
| Grant date | Apr 13, 2021 |
| Priority date | — |
| Expiry date | Feb 19, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2413/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A privacy display comprises a polarised output spatial light modulator, reflective polariser, plural polar control retarders and a polariser. 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. Further, display reflectivity is reduced for on-axis reflections of ambient light, while reflectivity is increased for off-axis light. The visibility of the display to off-axis snoopers is reduced by means of luminance reduction and increased frontal reflectivity to ambient light. In a public mode of operation, the liquid crystal retardance is adjusted so that off-axis luminance and reflectivity are unmodified.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.