Patent ID: 7504648
Filing Date: 2009-03-17
Classification: G03B

Abstract:
1. A non-imaging tool for assisting in determining a focus in a scanning system that scans a planar object with a scanning beam in a fast scan direction, while the planar object is moved under the scanning beam in a slow scan direction perpendicular to the fast scan direction, the tool comprising: a plate having a planar surface; a focusing wedge mounted on the plate; and a ramped grating which forms part of the focusing wedge and which has a tilted surface which extends from above the plate surface to below the plate surface; the ramped grating including alternating, parallel first stripes and second stripes, wherein the first and second stripes are one of, respectively, fluorescent and non-fluorescent stripes, storage phosphor and non-storage phosphor stripes, and reflective and non-reflective stripes.