Automatic focusing device and automatic focusing method
US5497209A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 27, 1994 |
| Grant date | Mar 5, 1996 |
| Priority date | — |
| Expiry date | Dec 27, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
To improve focusing precision and responsiveness in an automatic focusing device, an accurate lens driving amount is found in a short time from a detected defocus amount. A conversion coefficient .gamma.s is calculated by successively correcting a correction coefficient Lm using the next correction coefficient L(m+1) and the defocus amount .DELTA.Bf and by correcting the specific conversion coefficient .gamma. using these correction coefficients and the defocus amount .DELTA.Bf. Driving of the focusing lens is controlled by calculating a driving amount .DELTA.x for the focusing lens from the defocus amount .DELTA.Bf using the conversion coefficient .gamma.s.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.