Patent ID: 7151602

Claim:
A particle size distribution analyzer comprising: a transparent cell for containing a sample containing particles to be analyzed; a laser light irradiating section for irradiating the sample with a laser light from outside of the cell; a scattering light intensity detecting section for detecting the intensity of light scattered from the particles irradiated with the laser light; a calculating section for calculating a particle size distribution of the particles based on a fluctuation of the intensity of scattering light measured which occurs due to Brownian motions of the particles; and a noise reducing section operative to reduce the amount of noise-causing scattering light becoming incident on the scattering light intensity detecting section, the noise reducing section comprising a region to be irradiated with the laser light of at least one of an outside surface and an inside surface of the cell, the region being inclined a predetermined angle with respect to an optical axis of the laser light.