Varifocal lens
US5574598A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1994 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Aug 5, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B3/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A varifocal lens whose variable focal length can be controlled by, for example, an electric signal, and suitable for use in bar code readers, etc. A varifocal lens comprises a first pressure chamber defined between a glass substrate and a transparent elastic film. The transparent elastic film is faced to the surface of the planar glass substrate having parallel surfaces with a spacer incorporated therebetween to provide the first pressure chamber. A pump is provided adjacent to the first pressure chamber via a communicating path for charging an operating liquid to the first pressure chamber from a second pressure chamber of the pump by electrically deforming the transparent elastic film to form a lens having a variable focal length. The transparent elastic film has a film thickness distribution as such to provide a spherical plane in the central portion thereof and a third order curved surface in the periphery thereof. In this manner, a lens free of aberration can be obtained when a liquid is fed into the first pressure chamber to form a spherical plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.