Illumination optical system
US4717242A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1985 |
| Grant date | Jan 5, 1988 |
| Priority date | — |
| Expiry date | Dec 19, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0018
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illumination optical system having a light source for supplying a light beam to illuminate an object and a collimator lens system for collimating the light beam emitted from the light source, the collimator lens system being arranged such that, even if any ghost beam is produced from a lens surface of the collimator lens system, the intensity of the ghost beam per unit area on the object is suppressed to such degree that does not cause deterioration of resolution. For this purpose, in an embodiment of the invention, the lens surface of the collimator lens system is shaped in a specific manner so as to control the position at which the ghost beam is concentrated or to be concentrated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.