Holographic multi-combiner for head-up display
US4688879A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 8, 1985 |
| Grant date | Aug 25, 1987 |
| Priority date | — |
| Expiry date | Jul 8, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0118
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A head-up display which combines an internal image, produced by a cathode ray tube image source, at substantially a wavelength of light .lambda., with an external image, using a holographic optical element. The holographic optical element consists of two or more holographic optical subelements in series, each satisfying the Bragg condition with respect to wavefronts at the wavelength .lambda. from a particular direction. While wavefronts satisfying these conditions are reflected to the observer's field of view, all others are transmitted through the holographic subelements. The holographic optical subelements largely overlap in the direction of their illumination by the internal image source, and may slightly overlap in the direction their images are to be presented to the observer. Wavelength .lambda. is chosen at the peak of the phosphor response curve of the cathode ray tube image source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.