Clear holographic helmet visor and process of producing same
US4874214A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 1988 |
| Grant date | Oct 17, 1989 |
| Priority date | — |
| Expiry date | Apr 18, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0145
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The visor can be readily mounted on a helmet by virtue of the fact that it dispenses with the need for any optical relay system. Provision is made for a light image generator, an optical combining and collimating assembly in which a holographic flat plate and a holographic spherical plate are grouped together so as to provide a view of the collimated image superimposed on the landscape. The holographic spherical plate is employed off the axis and produces collimation in a pupil zone placed substantially at the focal distance of the apex of the spherical mirror. The hologram of the spherical plate is recorded by means of a digital hologram in order to minimize aberrations. The flat plate can be fairly steeply inclined with respect to the sighting axis and so designed as to reduce the ratio of parasitic reflection of the imaging channel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.