Patent ID: 8625093

Claim:
A particle characterization device comprising: a transparent cell that contains a sample in which a micro particle is dispersed in a dispersion medium; an illumination optical system mechanism having an incident side polarizer and an incident side ¼ wavelength plate that are sequentially provided on a light path from a light source to the cell arrived by primary light emitted from the light source; a light receiving optical system mechanism that has: light detecting means adapted to detect an intensity of received light; and an exit side ¼ wavelength plate and an exit side polarizer that are sequentially provided on a light path through which secondary light scattered by the particle in the cell travels to the light intensity detecting means, and is rotatably supported around the cell; light attenuating means adapted to, without changing a polarization state of the primary light or the secondary light, attenuate the light with being able to change a light attenuation rate; an angle control part that controls the light receiving optical system mechanism to a plurality of rotational angle positions, and at each of the rotational angle positions, controls a polarization angle of the exit side polarizer to a plurality of angles; a light attenuation rate control part that controls the light attenuation rate by the light attenuating means such that a detected light intensity at each of the polarization angles at each of the rotational angle positions falls within a measurement range of the light detecting means; and a physical property calculation part that calculates a physical property of the particle on a basis of a light attenuation rate at each of the polarization angles at each of the rotational angle positions and a detected light intensity after the light attenuation.