Surface features for imaging directional backlights
US11067738B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2020 |
| Grant date | Jul 20, 2021 |
| Priority date | — |
| Expiry date | Jun 30, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2013/403
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An imaging directional backlight apparatus includes a waveguide and light source array for providing large area directed illumination from localized light sources. The waveguide may include a stepped structure in which steps may include extraction features optically hidden to guided light, propagating in a forward direction. Returning light propagating in a backward direction may be refracted, diffracted, or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. Viewing windows are formed through imaging individual light sources and defines the relative positions of system elements and ray paths. Alignment of the waveguide to mechanical and optical components may be provided by surface relief features of the waveguide arranged in regions adjacent the input surface and intermediate the light emitting regions of the light sources. Efficient, uniform operation may be achieved with low cross talk for application to autostereoscopic and privacy modes of operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.