Patent ID: 6417920
Filing Date: 2002-07-09
Classification: G01N

Abstract:
A particle size analyzer based on laser diffraction method, comprising:an irradiation optical system for irradiating laser beam to particles, said irradiation optical system having a semiconductor laser in an output beam wavelength of 300 to 500 nm as a light source and a casing with a window containing the semiconductor laser; a measurement optical system situated near the irradiation optical system for measuring a space intensity distribution by receiving light diffracted/scattered by particles of the laser beam from the irradiation optical system, said measurement optical system including a plurality of light sensors disposed in an area of a predetermined front angle in an irradiating direction of the laser beam, a converging lens for converging light diffracted/scattered by a particle group to be measured, a ring detector disposed at a focal position of the converging lens and formed of a plurality of independent conical light receiving surfaces in a shape of a ring, half ring or {fraction (1/4+L )} ring having different radii, an xy axes position control mechanism connected to the ring detector, and a casing with a window, said casings being spaced apart from each other so that the windows face to allow the laser beam to pass through the windows; and an operation portion connected to the measurement optical system for obtaining a particle size distribution of the particles from results measured by the measurement optical system.