Method and apparatus for detecting surface deviations from a reference plane
AssigneeOpal Technologies Ltd.
InventorArie Shahar
Life of this patent
Estimating the term…
Abstract
A method and apparatus for detecting deviation of an examined surface from a reference plane, by: generating first and second beams of radiation, directing the first beam along a first fixed path and focussing it at a first spot on the examined surface, directing the second beam along a second fixed path intersecting the first path at a point in the reference plane and focussing the second beam to a second spot on the examined surface, and detecting the deviation of the centers of the first and second spots with respect to the intersection point in the reference plane to provide an indication of the deviation of the examined surface from the reference plane.
Claims20
A method of detecting deviation of an examined surface from a reference plane, comprising:
- generating first and second beams of radiation;
- directing said first beam along a first fixed path and focussing the first beam to a first spot on a surface to be examined;
- directing said second beam along a second fixed path intersecting said first path at a point in said reference plane and focussing said second beam to a second spot on said examined surface;
- and detecting the deviation of the centers of said first and second spots with respect to said intersection point in the reference plane to provide an indication of the deviation of said examined surface from said reference plane.
Apparatus for detecting the deviation of an examined surface which reflects radiation from a reference plane, comprising:
- beam generating means for generating first and second beams of radiation;
- first beam directing means for directing said first beam along a first fixed path and focussing the first beam to a first spot on a surface to be examined;
- second beam directing means for directing said second beam along a second fixed path intersecting said first path at a point in said reference plane and focussing said second beam to a second spot on said examined surface;
- and detecting means for detecting the deviation of the centers of said first and second spots with respect to said intersection point in the reference plane to provide an indication of the deviation of said examined surface from said reference plane.
Dependencies are inferred from the claim text.