Prism for image rotation
US5191485A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 19, 1991 |
| Grant date | Mar 2, 1993 |
| Priority date | — |
| Expiry date | Sep 19, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/11
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An assembly for rotating an image formed by a group of light rays has a first prism with a transparent first facet through which the light rays enter. The image light rays entering the first facet strike a second facet at angles of incidence greater than the critical angle and are reflected toward a third facet. The third facet is silvered to reflect substantially all of the image light rays back toward the second facet so that the light rays strike the second facet at less than the critical angle and exit the first prism. A second prism is spaced from the first prism to receive light rays from second facet. After entering the second prism, such light rays strike one of its facets and are reflected toward and through an exit facet. The facets of the second prism are angled to minimize image distortion and compensate for lateral offset of the light rays exiting the assembly. A version of the assembly is described in which the second prism is replaced by a mirror.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.