Focal-length adjusting unit for photographing apparatuses
US6658208B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 2001 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | Sep 25, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A focal-length adjusting unit for photographing apparatuses includes a distance-measuring means for detecting the amount of defocus to an object by using a light beam of the object passing through a photographing optical system; at least two optical elements located in an optical path for distance measurement, deflecting incident light from the object to introduce the light into an image sensor or a distance-measuring sensor; a variable optical-property element constituting at least one of the optical elements, capable of changing the deflection of light in accordance with an applied voltage or an applied current; and a voltage applying means or a current applying means for applying a voltage or a current in accordance with the distance-measuring output of the distance-measuring means. In this case, before a distance measurement is made by the distance-measuring means, the function of light deflection of the variable optical-property element is set to a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.