Focus detecting apparatus with both passive and active focus capability
US4843227A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1987 |
| Grant date | Jun 27, 1989 |
| Priority date | — |
| Expiry date | Sep 11, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/285
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A focus adjusting system is provided with both a passive AF capability wherein ambient light is utilized and an active AF capability wherein an LED element for projecting light off the optical axis of a photo-taking lens and light reflected from an object after having been projected by the LED element are utilized. The focus detecting apparatus includes a secondary image forming element and an aperture opening disposed in the vicinity of the secondary image forming element. The aperture opening is symmetrically positioned relative to the optical axis of the photo-taking lens and lies on a straight line which contains the optical axis of the photo-taking lens and which is perpendicular to a straight line connecting the optical axis of the photo-taking lens and a projecting light optical axis. The aperture opening has a pair of inner regions and a pair of outer regions. A first cut-off filter having a property of cutting off rays of light of a wave-length projected from the LED element is provided. First and second AF sensors are adapted to receive the light, which has passed through at least the pair of the outer regions of the aperture opening, and the light which has passed throug…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.