Photoelectric rangefinder
US4209241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 11, 1978 |
| Grant date | Jun 24, 1980 |
| Priority date | — |
| Expiry date | Oct 11, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photoelectric rangefinder for use in a photographic camera for automatically focusing an image of a target object on a predetermined image plane. The system utilizes an electro-optical spatial filter having at least two photoresponsive elements to find the difference in phase between output signals from the respective photoresponsive elements. A signal indicative of the difference in phase between the output signals from the photoresponsive elements is used to move a phototaking objective lens along its optical path to reposition the objective lens in search for a true focus setting. The objective lens is brought into proper focus when the signal indicative of the phase difference assumes a predetermined electric relation with an electric signal indicative of the position of the objective lens along its optical axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.