Optical apparatus for changing focus and focal length
US5333024A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 1, 1993 |
| Grant date | Jul 26, 1994 |
| Priority date | — |
| Expiry date | Mar 1, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Optical apparatus having first and second lens groups moveable along an optical axis, and a cam and follower mechanism for communicating relative axial displacement to the second lens group in response to axial movement of the first lens group for changing the focal length of the optical system. The cam and follower mechanism is characterized by a plurality of cam steps each having first or dwell surfaces for maintaining the relative axial displacement constant in response to axial movement of the first lens group, to accommodate focusing between at least two focus positions at a fixed focal length, and second or ramp surfaces for changing the relative axial displacement in response to axial movement of the first lens group, for changing the focal length of the apparatus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.