Focus state detection device
US5293034A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1991 |
| Grant date | Mar 8, 1994 |
| Priority date | — |
| Expiry date | Jun 4, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/34
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A focus state detection device comprising: a first optical conversional system for forming an optical flux in one of two symmetric regions with respect to an optical axis of an optical flux from a subject to be photographed; a second optical conversional system for forming an optical flux in the other of the two symmetric regions; and a third optical conversional system for forming an optical flux in a region including the optical axis. The device further comprises a first and a second photoelectric converters for generating electric signals in response to optical intensity distribution data of the fluxes formed by the first and second systems, respedtively; a third photoelectric converter for generating an electric signal in response to optical intensity distribution data of the flux formed by the third system; and a calculation unit for detecting a focus state of the subject on the basis of correlation between three electric signals output from the first, second and third converter means.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.