Patent ID: 7417734

Claim:
A system for sorting a biological particle in accordance with biological information thereof, comprising: a path-defining structure which defines a liquid flow arranging a plurality of biological particles at a predetermined interval therein, and ejects the flow to form a droplet containing the biological particle; an irradiator for irradiating light onto the biological particle contained in the flow; an optical detector for detecting the light from the biological particle at a detection point; a stationary imaging device for imaging the flow and a droplet split off the flow in an image region having an upstream end that is spaced downstream from the detection point by a constant first distance; means for calculating, based upon the image taken by the imaging device, a second distance from the upstream end of the image region to a break-off point of the flow, and a droplet interval between adjacent droplets split off the flow, thereby calculating a time that the particle moves from the detection point to the break-off point, based upon the first and second distances and the droplet interval; means for providing the flow with electrons of a predetermined polarity depending upon the feature of the biological particle, when the calculated time passes after the optical detector detects the light from the biological particle.