Optical projection device and an optical reader incorporating this device
US4037929A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1976 |
| Grant date | Jul 26, 1977 |
| Priority date | — |
| Expiry date | Aug 30, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/294
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This invention relates to a projection device of which the optical device having a focal length is variable under the effect of an electrical signal and comprises a hollow transparent lens into which a liquid nematic crystal is introduced. Under the effect of the electrical signal applied between two transparent electrodes respectively arranged on the two inner surfaces of the lens, the index of the liquid crystal for the direction of incidence of the projected beam is capable of varying as a result of the oscillation of the molecules of the liquid crystal, the position of the focussing point of the projected beam varying in consequence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.