The invention discloses a
particle size analyzer which is characterized in that a
microscope objective is arranged below an area array sensor; a sample tank is arranged on the focusing plane of the
microscope objective; two light sources, namely a transmission
light source and a scattering
light source are arranged below the sample tank; when micron-grade particles are measured, the transmission
light source emits illumination light to illuminate particle samples to be detected, particle images are amplified by the
microscope objective to be imaged on an
image plane, and image signals obtained after receiving of the images by the area array sensor are transmitted to a computer to be processed to obtain
particle size distribution; when nano particles are measured, the transmission light source is turned off while the scattering light source is turned on,
laser emitted by the transmission light source is irradiated to nano particle samples,
dynamic light scattering signals generated by Brownian movement of the nano particles are received by the area array sensor through the
microscope objective, and the obtained signals are transmitted to the computer to be processed to obtain the
particle size distribution. According to the
particle size analyzer, the particles with the size range from nanometers to hundreds of microns can be measured by only one
image sensor, so as to meet the requirements of wide-range particle measurement.