Holographic lenses with wide angular and spectral bandwidths for use in a color display device
US5680231A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | Oct 21, 1997 |
| Priority date | — |
| Expiry date | Jun 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H1/26
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The angular and/or spectral bandwidth of a holographic lens assembly can be widened to accomodate highly diverging and/or wide spectral bandwidth illumination sources, respectively. Each lens in the lens assembly is comprised of a plurality of angularly customized holograms (an angularly customized hologram set). Each of the individual holograms in an angularly customized hologram set has an acceptance angle range that is centered on a discrete peak acceptance angle. The separation between the holograms' peak acceptance angles is chosen so that the acceptance angle ranges of the individual holograms overlap. The resulting cumulative acceptance angle range of each angularly customized hologram set provides a holographic lens assembly that has a wider angular bandwidth than prior holographic lenses. The spectral bandwidth of the lens assembly can be similarly widened by adding a spectrally customized hologram set to the lens assembly in which the spectral waveband of each of the individual spectrally customized holograms partially overlap. Specific applications to various types of displays are disclosed, as well as preferred fabrication techniques for the holographic lenses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.