Autofocus system
US6809883B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2003 |
| Grant date | Oct 26, 2004 |
| Priority date | — |
| Expiry date | May 3, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/343
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An autofocus system for an imaging device that includes an image detecting element for image production at a focused image plane of an adjustable focus imaging lens that also includes four image detecting elements for focus detection arranged in pairs that are equidistant in front of, and behind, planes that are conjugate with the focused image plane. One pair of image detecting elements for focus detection are farther than the other pair from the conjugate planes and may be used alone for focusing based on the stop value or focal length of the adjustable focus imaging lens. Alternatively, the other pair of image detecting elements may be used for more accurate focusing after the one pair of image detecting elements is used. The use of two pairs of image detecting elements at different distances from the focused image plane provides accurate focusing over a wide range of object distances.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.