Particle measuring apparatus

A particle measuring device for measuring a particle contained in a sample containing a solvent and the particle, the particle measuring device comprising:

• a light source configured to emit light;
• a condenser lens configured to condense the light and irradiate the sample with the light;
• a two-dimensional scanner configured to repeatedly scan a focal position of the light in a three-dimensional region in the sample;
• a photodetector configured to detect reflected light from the particle;
• an image generation unit configured to generate a three-dimensional image of the sample based on a signal detected by the photodetector;
• and
• an analysis unit configured to analyze the three-dimensional image, wherein
• the analysis unit calculates two or more of
• one or more parameters that are obtained based on a maximum intensity of the reflected light from the focal position during a process of repeatedly scanning the focal position along an optical axis direction of the light in the three-dimensional region, and that indicate a type of the particle, and
• one or more parameters that are obtained based on a position of the particle acquired by continuously tracking the particle and that indicate a type of the particle, and
• outputs a calculation result;
• wherein the analysis unit outputs, as the parameters, two or more of
• the maximum intensity,
• a sphericity of the particle calculated based on the maximum intensity obtained by causing the focal position to repeatedly reciprocate in the three-dimensional region along the optical axis direction,
• a diffusion constant of the particle calculated based on a change in time in a position of the particle, or a size of the particle calculated based on the diffusion constant, and
• a sedimentation velocity of the particle calculated based on a change in time in a position of the particle in a gravity direction.