Autofocus system
US6624403B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 11, 2001 |
| Grant date | Sep 23, 2003 |
| Priority date | — |
| Expiry date | Oct 11, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/32
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An autofocus system for maintaining a sample in the focal plane of a primary lens is disclosed. A light source generates a monitor beam which is focused onto the sample through the primary lens. The reflected beam passes back through the primary lens and is directed to a secondary lens. The beam is then split by a reflective wedge into two portions with different path lengths such that the beam waists of the two portions are spatially separated. An aperture is located between the two beam waists. A bi-cell photodetector measures the intensity of the two beam portions transmitted by the aperture. The measured intensity levels vary with respect to the position of the sample. By comparing the measured intensity levels, an indication of the position of the sample can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.