Apparatus for detecting and displaying position of a lens on an optical axis
US5859733A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1996 |
| Grant date | Jan 12, 1999 |
| Priority date | — |
| Expiry date | Sep 24, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/102
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A lens holding frame holding a lens in a lens barrel is arranged, and a contact member extending therebelow is in friction coupling with a driving axis. By applying driving pulses having such a waveform that includes a moderate rising portion followed by an abrupt falling portion to a piezoelectric element, the holding frame is moved along the direction of the optical axis. An index provided at the holding frame is exposed through a slit of lens barrel, and from the position of the lens on the holding frame, information with respect to the distance to the object is displayed. Detection of the position of the holding frame is performed by a position sensor of ferromagnetic thin film magneto-resistive element type (MR sensor) so as to obtain positional information of the lens on the holding frame based on the detection signal, and the obtained information may be displayed on a liquid crystal or other display portion provided on the lens unit or on a camera body.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.