Projection optical system and method of using such system for manufacturing devices
US5930049A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Jun 13, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/143
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection optical system is provided which forms an image of a first object onto a second object and includes, in order from the first object side: a first positive lens group G1 with a subgroup G-1p having at least two positives lenses; a second negative lens group G2 with a subgroup G-2n having at least three negative lenses; a third lens group G3 with a subgroup G-3p having at least three positives lenses and one negative lens; a four negative lens group G4 with a subgroup G-4n having at least three negative lenses; a fifth positive lens group G5 with a subgroup G-5p having at least five positives lenses and having a positive lens G-5g arranged closer to the second object side than the subgroup G-5p and having a concave surface facing the second object side. The projection optical system provides an optimal range for the focal length and the preferable range of the radius of curvature for the concave surface R5g of the positive lens G-5g.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.