| 摘要 |
PURPOSE:To enhance measuring accuracy, by placing a reference plate at a position where a particle group to be tested is placed and comparing the actually measured value of incident light to a detector with a theoretical value to perform the adjustment of an optical axis before performing measurement. CONSTITUTION:At first, a reference plate 1 having a large number of circular apertures or beam scattering parts formed thereto is placed at a position P. The laser beam from a beam source 4 is converted to parallel beam by collimator lens 5a, 5b and passed through the reference plate 1 to be formed into a diffraction image on a ring detector 3 through a lens 2. The output of each element of the detector 3 is stored in RAM 11 through a multiplexer 7, an amplifier 8, and an A/D converter 9. CPU 10 compares the data of the theoretical intensity distribution preliminarily stored in ROM 12 with the data of RAM 11 and moves the lens 2 or the detector 3 so as to allow both data to coincide to adjust an optical axis. Thereafter, the reference plate 1 is replaced with optical axis. Thereafter, the reference plate 1 is replaced with a particle group to be tested to enable highly accurate measurement. |
