High numerical aperture and long working distance objective system using diffraction-type optical elements
US5748372A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 17, 1996 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | Apr 17, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/4277
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention provides a high-magnification and high-NA objective having a long working distance, which is corrected for various aberrations, especially chromatic aberrations over a wide wavelength range and allowed to have an aligning pupil position without making much use of cemented lenses and anomalous dispersion glass. The objective comprises a first lens group G1 including a meniscus lens concave on the object side and having a positive power as a whole, two optical elements of the diffraction type (DOEs), and a second lens group G2 including at least one cemented lens, and satisfies the condition for ensuring the edge thickness of the front lens as well as either one of two conditions for making effective correction for longitudinal chromatic aberration and chromatic aberration of magnification.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.