Light-scattering detection device

A light-scattering detection device for detecting fine particles in a liquid sample, comprising:

• a transparent sample cell configured to hold the liquid sample;
• a light source configured to emit coherent light to the sample cell;
• imaging optics configured to collect light scattered from the sample cell to a periphery thereof at different scattering angles, the imaging optics including a lens;
• a slit plate configured to limit a scattering angle range, the slit plate being arranged on an incident side of the imaging optics;
• a detector configured to receive collected light from the imaging optics;
• and
• an aperture plate configured to limit a width of light received by the detector by an aperture width, the aperture plate being arranged further toward a detector side than a focal length of the imaging optics,
• wherein a plurality of detection optical systems extending from the sample cell to the detector is arranged around the sample cell at equal intervals from a central axis of the sample cell, each of the plurality of detection optical systems having the imaging optics, the slit plate, the detector, and the aperture plate, the plurality of detection optical systems having a plurality of detectors,
• wherein the plurality of detectors includes at least three detectors, the at least three detectors including a first detector arranged at a first position closer to a reference position, a third detector arranged at a third position further away from the reference position, and a second detector arranged at a second position between the first detector and the third detector, the second position being closer to the reference position than the third position and further away from the reference position than the first position, the reference position being defined as a position at which an angle with respect to an incident direction of the coherent light to the sample cell is 90°,
• wherein the aperture width of the aperture for the first detector is larger than the aperture width of the aperture for the second detector and the aperture width of the aperture for the second detector is larger than the aperture width of the aperture for the third detector, and
• wherein the aperture width of each aperture plate is a value obtained by multiplying a distance from the central axis of the sample cell to the detector by a sine value of an arrangement angle of each detector.