Off-axis display device
US11099448B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 2020 |
| Grant date | Aug 24, 2021 |
| Priority date | — |
| Expiry date | Nov 12, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10K59/8793
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A switchable backlight for a switchable privacy display apparatus comprises a collimated backlight arranged to provide two off-axis beams and at least one polar control liquid crystal retarder arranged between parallel polarisers. The alignment layers of the liquid crystal retarder are rotated with respect to the electric vector transmission direction of the polarisers. In use in the centre stack of a vehicle, in one mode of operation high image luminance and high image visibility is provided for the passenger while the image is invisible to the driver. In another mode of operation an image is provided to the driver with low stray light to the passenger for night time operation. In a third mode of operation both passenger and driver can see an image with high luminance and image visibility.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.