Stepless micrographic zoom lens having large magnification ratio
US5481405A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 1993 |
| Grant date | Jan 2, 1996 |
| Priority date | — |
| Expiry date | Nov 30, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/143
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A stepless zoom lens useful in micrographic applications providing stepless magnfications from 6.8x to 32x, a zoom ratio exceeding 4.7 to 1. Fourteen elements are arranged in three groups. An object to image distance of 1,750 millimeters is maintained. The first group consists of a cemented doublet air spaced from a single meniscus element, for a total of three elements in the group. The second group consists of a meniscus element air spaced from a cemented doublet, which is in turn air spaced from a second meniscus element, a total of four elements in the group. The third group consists of a biconvex element air spaced from a cemented doublet, followed in order by an air space, a meniscus, an air space and a final doublet, for a total of seven elements in the group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.