The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 22, 2014
Filed:
Jan. 10, 2013
Daniel R. Marshall, Boise, ID (US);
Daniel R. Marshall, Boise, ID (US);
Other;
Abstract
This focus sensor is readily usable in a system using pupil obscuration to measure the state of focus of a light beam. A scattering volumetric filter modifies a three-dimensional wavefront so that focus can be detected by a two-dimensional detector for conversion to a one-dimensional signal having values of plus, zero and minus. This diffusing filter comprises sub wavelength particles having a high index of refraction suspended in an adhesive to produce a solid diffuser. This focus sensor enables a well-behaved focus curve having a constant slope near best focus, while maintaining a slope that is either constant or monotonic at a minimal rate over an extended distance to support a long capture-range over which a focus-controlling servo-mechanism can acquire and maintain focus in the presence of corrupting target surface topography or optical defects.