Method and apparatus for adjusting imaging performance of projection optical apparatus
US4871237A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1987 |
| Grant date | Oct 3, 1989 |
| Priority date | — |
| Expiry date | Nov 12, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a method and apparatus for highly precisely adjusting the optical performance including the imaging plane and the magnification factor of a projection lens in a projection optical apparatus, adjustment of the projection lens is achieved by changing the barometric pressure, i.e., the refractive index of at least one space which is located on an optical path and which is shielded from the outer atmosphere is changed by changing the barometric pressure therein. At this space, a space or gap present between any two adjacent elements of a plurality of lens elements or a group of lenses constituting a projection lens is preferably selected. The selected space is independent from and is shielded from the outer atmosphere by the lenses defining itself and a housing supporting these lenses, and is filled with air or a gas. The pressure of the air or gas inside the independent space is controlled by a barometric controller.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.