Focus detecting device
US4346970A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1980 |
| Grant date | Aug 31, 1982 |
| Priority date | — |
| Expiry date | Aug 19, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a TTL (Through-The-Lens) type focus detecting device for use in an interchangeable lens-equipped camera, in which a plurality of lenslets are positioned at or near the prescribed focal plane of the objective lens, each of the lenslets is associated with two or more pairs of photosensitive elements. Upon attachment of an objective lens to the camera body, one of the pairs of photosensitive elements for each lenslet is automatically selected to operate on the basis of the dimensions of the used objective lens. The outputs of the selected pairs of photosensitive elements for all the lenslets are processed to detect whether or not a positional difference between two images of an object formed with light beams from the objective lens at respective virtual exit pupils lying in almost symmetry with respect to the optical axis thereof is present, whereby the detection of whether or not the objective lens is in-focus is indicated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.