摘要 |
A device for detecting the edges of a workpiece held on the chuck table of a processing machine, having a beam oscillation means for oscillating a detection beam, an objective lens for focusing the detection beam oscillated from the beam oscillation means, and a reflected light detection means for detecting the reflected light of the detection beam applied through the objective lens, wherein the beam oscillation means oscillates the detection beam in such a manner that the optical axis of the detection beam becomes parallel to the center axis of the objective lens at a position offset from the center axis; and the reflected light detection means detects the edge of the workpiece based on a positional difference between reflected light obtained when the detection beam applied through the objective lens is reflected on an area where the workpiece is not existent and refracted by the objective lens and reflected light obtained when the detection beam is reflected on the workpiece and refracted by the objective lens.
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