Objective lens system
US5469299A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 23, 1993 |
| Grant date | Nov 21, 1995 |
| Priority date | — |
| Expiry date | Nov 23, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high resolution objective lens system for use in the ultraviolet region around 250 nm comprising in order from the object side: a first lens unit comprising a meniscus lens component having an object side concave surface having high curvature and a positive lens component, and having a positive refractive power as a whole; a second lens unit comprising at least two cemented lens components and having a positive refractive power as a whole; and a third lens unit comprising a cemented lens component and having a negative refractive power as a whole: each of the lens elements arranged in the lens units being made of an optical material which has, a thickness of at least 5 mm, and an internal transmittance of at least 50% for a ray having a wavelength of 300 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.