Focus detection apparatus having extended detection range
US7723657B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 2008 |
| Grant date | May 25, 2010 |
| Priority date | — |
| Expiry date | Dec 29, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J1/0411
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An extended range focus sensor is provided. In various embodiments, the focus sensor may include a relay lens assembly to image a plane between an objective lens and the relay lens arrangement to a plane near an entrance pupil of a focus detector arrangement of the focus sensor. In some embodiments, the objective lens pupil is imaged onto the focus detector entrance pupil. In some embodiments, an illumination beam passes through the relay lens arrangement and is magnified on its way to be output by the objective lens, and the reflected focus detection beam passes back through the objective lens and the relay lens arrangement and is reduced prior to being input to the focus detector arrangement. In some embodiments, the focus detector arrangement may comprising a broad range focus detector combined with a high resolution Shack-Hartmann focus detector, and in others a single extended range Shack-Hartmann focus detector is used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.