Dynamic focusing method and apparatus

US7321108B2 · kind B2 · utility

Assignee

• Rudolph Technology, Inc. · US

Inventors

• Cory Watkins · Chanhassen, US
• Mark Harless · Plymouth, US
• David Vaughnn · Edina, US
• Pat Simpkins · Edina, US
• Shaileshkumar Goyal · Gothan, IN
• Gerald Brown · Landenberg, US
• Brian Delsey · Farmersville, US

Key dates

• Filing date: Jan 22, 2007
• Grant date: Jan 22, 2008
• Expiry date: Jan 22, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B21/245
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and apparatus for dynamically focusing an imaging mechanism on a moving target surface having a variable geometry is herein disclosed. Apparatus for focusing an imaging mechanism may include an objective, a prism, or another optical device that forms part of an optical train of an imaging mechanism, a sensor for measuring a distance to the target surface, and a mechanism for modifying the depth of focus of the objective, prism or other optical device. Data from the sensor may be used to create a predictive model of the target surface. Data from the sensor is also used to fit or correlate the generated model to an exemplary target. Data from the correlated model is used to drive the mechanism for modifying the depth of focus of the objective, prism, or other optical device to maintain the surface of the exemplary target in focus.