摘要 |
An adaptive light-path surface tilt sensing configuration is provided that identifies when a ray bundle is projected along a direction normal to a workpiece surface. As a result, the tilt of the workpiece surface may be determined. The surface tilt sensor may comprise an illumination and detector portion and an objective lens. The illumination and detector portion may comprise a light source, a collimating lens, a beamsplitter, a controllable ray bundle position control portion, and a photodetector configuration. These elements are configured to provide a ray bundle alignment sensing arrangement that provides a signal indicating when a projected ray bundle and a reflected ray bundle have the best degree of alignment, in addition to other functions. The best degree of alignment corresponds to a ray bundle that is projected along the direction normal to the workpiece surface.
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