High magnification reflecting microscope objective having a dual magnification mode and zoom magnification capability
US4863253A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 1987 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Sep 25, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/04
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A modified Schwarzschild Casegrainian objective reflects radiant energy between the primary and secondary mirror two times to form a four reflection optical path. The four reflection optical path increases the magnification of the objective without making the working distance that separates the secondary mirror from the sample unacceptably small. The four reflection optical path maintains good image quality at high numerical aperture due, at least in part, to the relatively small size of a microscopic object. The objective functions as a zoom lens by changing the location of a remote field stop along the optical axis of the objective and refocusing because the emerging beam of radiant energy is nearly collimated along the optical axis at the field stop. The reflecting objective also obtains variable magnification by converting to a two reflection mode of operation by increasing the separation of the primary mirror from the secondary mirror from the sample image plane. The two reflection mode provides for less magnification than obtained with the four reflection mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.