Holographic optical display system with optimum brightness uniformity
US4655540A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1985 |
| Grant date | Apr 7, 1987 |
| Priority date | — |
| Expiry date | Apr 23, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0118
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical display system employs a holographic optical element that has a holographic fringe pattern which is coordinated with the phosphor emission peak of a cathode ray tube to eliminate perceptible variations in image brightness. The holographic optical element has a reflection characteristic that defines two diffraction efficiency peaks which are resolved by a low diffraction efficiency dip that is interposed between them. The optimum wavelength spacing between the two diffraction efficiency peaks for a given wavelength spacing is determined by computing for all observer head positions and look angles of concern the differences among the areas under the integrated efficiency characteristics for the reflection characteristic of the holographic optical element and the phosphor emission characteristic of the image-producing cathode ray tube. The optimum wavelength spacing is that which provides the desired variation among the computed difference values, which respresent the display brightness uniformity. The center dip reflection characteristic increases the spectral bandwidth of the holographic optical element and thereby increases its reflectivity to promote good contrast with …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.