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Applied Optics, vol. 17, No. 17, Sep. 1978, pp.
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the Focal Region", (see FIG. 1, p. 1).
Abstract of JP 62-163933 (Nippon Kogaku K.K.) Jul.
Primary Examiner—Richard A. Rosenberger
Assistant Examiner—Hoa Q. Pham
Attorney, Agent, or Firm—Lyon & Lyon
An apparatus and a method for profiling the intensity of a beam and thus measuring the overall intensity and power of a beam are disclosed that have particular use in stereolithography. A beam sensor comprising a pinhole in a plate and a photodetector behind the pinhole measures the intensity of portions of a beam as the beam is moved over the beam sensor. Software associated with the sensors in a computer controls the scanning mechanism for the beam so that the beam is shifted to find the pinhole and move across it in order to develop the intensity profile. The invention can be used to detect drift in the scanning mechanism, determine the focus of the beam, and predict the depth and width of photopolymer cured by the beam.
40 Qaims, 13 Drawing Sheets