Patent ID: 7499809

Claim:
A particle size distribution analyzer comprising: a transparent cell which stores a particles dispersed in a dispersion medium; a light source which emits light to the particles within the transparent cell; multiple light detectors dispersed and arranged so as to detect the intensity of diffracted and/or scattered light from the light source; optical equipment arranged between the light source and the light detectors; a calculating part which calculates the particle size distribution of the particles on the optical intensity signal output from the light detector; a cell storage space which is configured to operatively mount and release the transparent cell; and an equipment storage space which stores the light source, the multiple light detectors, and the optical equipment, the equipment storage space has a sealed construction which is separated from the cell storage space, wherein, the optical equipment is provided with a projection lens which refracts the light from the light source and a mechanical openable shutter arranged between the light source and the projection lens, and a drive source for the shutter arranged outside of the equipment storage space.