Fixed-focus lens
US7466501B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 2008 |
| Grant date | Dec 16, 2008 |
| Priority date | — |
| Expiry date | Jan 16, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/16
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A fixed-focus lens including a first lens group, a second lens group, and a third lens group arranged from an object side to an image side in sequence is provided. The first lens group has a negative refractive power, and includes at least one aspheric lens. The second lens group has a positive refractive power, and includes a lens. The third lens group has a positive refractive power, and includes a triple cemented lens. An effective focal length (EFL) of the fixed-focus lens is f. An EFL of the first lens group is f1. An EFL of the second lens group is f2. An EFL of the third lens group is f3. An axial distance between the first lens group and the second lens group is d. The fixed-focus lens satisfies: 2.5<|f1/f|<4.5, 7.5<f2/f<10, 4.5<f3/f<8.5, and 13<d/f<14.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.