Moving object extension controller
US5319498A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1993 |
| Grant date | Jun 7, 1994 |
| Priority date | — |
| Expiry date | Jan 28, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/08
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lens barrel drive unit for a camera, in which the present invention is implemented, comprises a lens barrel that is a moving object having a female screw, a drive screw that includes a male screw which engages with the female screw and that moves the lens barrel back and forth with the rotation of the male screw, a drive source for rotating the drive screw, a signal generator for generating a pulse signal according to the rotation of the drive source or drive screw, a first memory that stores a difference between a theoretical lead and an actual lead of the drive screw as a correction coefficient, a second memory that stores the theoretical number of pulses associated with a quantity of rotation of the drive screw which is required to drive the lens barrel to a given position corresponding to a subject distance, and a computing unit that uses the correction coefficient and the theoretical number of pulses to compute the actual number of pulses required for extending the lens barrel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.