Helmet visor display employing reflective, refractive and diffractive optical elements
US5526183A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 29, 1993 |
| Grant date | Jun 11, 1996 |
| Priority date | — |
| Expiry date | Nov 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/011
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An improved helmet visor display comprising three elements, including a tilted combiner, a refractive/diffractive relay module, and an image generator. The tilted combiner is a reflective-type combiner having either a spherical surface shape or a generalized aspheric surface shape. The relay module comprises a front-end collimating lens group, a pupil lens group in the middle, and a rear-end focusing lens group. The collimating lens group is comprised of one refractive doublet and one refractive-diffractive optical element. The combination of the refractive doublet and the refractive-diffractive optical element corrects for primary and secondary axial chromatic aberration, and significantly reduces higher order aberration as a result of power reduction in most lens elements. The pupil lens group comprises a conic or aspheric lens which reduces spherical aberration and enlarges the eye pupil. The focusing lens group comprises a refractive doublet and a wedge that relays the light emerging from the pupil lens group onto the image generator. A crown-flint refractive doublet in conjunction with a diffractive optical element may be employed in the focusing lens group to reduce primary a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.