Autofocus device
US4969003A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1989 |
| Grant date | Nov 6, 1990 |
| Priority date | — |
| Expiry date | May 5, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An auto-focus device or a camera equipped with such a device includes a focus detecting circuit for repeatedly detecting focus, in which an image forming optical system is driven on the basis of the focusing quantity detected by the focus detecting circuit. A speed computing circuit is provided for computing a speed of movement of an image plane corresponding to movement of the object on the basis of past autofocusing operation data. A drive data computing circuit is provided for predictive-computing data relating to a drive position of the image forming optical system, considering the movement of the object, on the basis of the past autofocusing operation data. A speed control circuit is provided for controlling a driving speed of the image forming optical system on the basis of the speed obtained by the speed computing circuit. A drive circuit is provided for driving the image forming optical system in one of a first mode in which a drive position of the optical system is controlled in accordance with data obtained by the drive data computing circuit without actuating the speed control circuit, and a second mode in which a driving speed of the optical system is controlled by the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.