Patent · US Active

Rules for reducing the sensitivity of fringe projection autofocus to air temperature changes

US9243901B2 · kind B2 · utility

1Cited by

0References

44Claims

0Family size

Assignee

NIKON CORPORATION · JP

Inventors

Eric Peter Goodwin · Oro Valley, US
Daniel Gene Smith · Tucson, US

Key dates

Filing date	Mar 13, 2013
Grant date	Jan 26, 2016
Priority date	—
Expiry date	Sep 5, 2033

Classification

Technology area (CPC G)Physics
CPC primaryG03F9/7026
WIPO fieldOptics
WIPO sectorInstruments

Abstract

Fringe projection autofocus systems are provided with variable pitch diffraction gratings or multiple diffraction gratings so that a reference beam and a measurement beam propagate along a common path. Alternatively, an input beam can be directed to a diffraction grating so that the selected diffraction orders propagate along a common path. In some examples, distinct spectral bands are used for reference and measurement beams.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.