초록 ▼

A method and improved system for automatically and substantially simultaneously focusing and orienting an interferometric optical system, such as an interferometric microscope (25) illuminated by broad-band light, with regard to a surface under test (66), for providing a best focus and orientation o

A method and improved system for automatically and substantially simultaneously focusing and orienting an interferometric optical system, such as an interferometric microscope (25) illuminated by broad-band light, with regard to a surface under test (66), for providing a best focus and orientation of objects to be measured. The optical system (20, 25, 30, 35, 37, 60, 40) includes a pixel array, such as a sparse array (30) onto which an interferogram is imaged. The pixel array (30) is scanned (20, 25) for detecting a peak fringe contrast for the pixels in the array (30) and the scan position at the detected peak fringe contrast for each pixel int he array (30) is saved (40). At least a portion, if not all, of the saved scan positions are fitted to a surface shape for providing a plane of best focus for the surface under test (66), and the surface under test (66) is automatically positioned (40, 35, 60) relative to the optical system for automatically focusing the object under test (66) across the plane of best focus.

대표청구항 ▼

[ What is claimed is:] [1.] A method for automatically and substantially simultaneously focusing and orienting an interferometric optical system with regard to a surface under test, said optical system comprising a short coherence light source for illuminating said optical system, a pixel array onto

[ What is claimed is:] [1.] A method for automatically and substantially simultaneously focusing and orienting an interferometric optical system with regard to a surface under test, said optical system comprising a short coherence light source for illuminating said optical system, a pixel array onto which an interferogram may be imaged, and means for scanning said interferometer through a zero optical path difference condition, said method comprising the steps of:detecting a peak fringe contrast for said pixels in said array;saving a scan position at said detected peak fringe contrast for said pixels in said array;fitting at least a portion of said saved scan positions to a surface shape for providing a plane of best focus for said surface under test; andpositioning said surface under test relative to said optical system for focusing said object under test across said plane of best focus.