PURPOSE: To detect fine particles with high resolving power, by a method wherein laser beam is projected to the liquid specimen flowing through a conduit so that the cross-section thereof becomes an oblique oval with respect to the center axis of the conduit and the scattering beam thereof is received.
CONSTITUTION: A liquid specimen is made to flow through a conduit 1 along the z-axis thereof. A cylindrical lens 2a is provided to an x-axis and the cylinder axis C thereof is inclined by an angle θ with respect to the z-axis and laser beam is condensed to an oval spot 4a on the z-axis being the center of the conduit 1. Then, the scattering beam from the oval spot 4a is received. At this time, the beam receiving axis R thereof is set in a direction forming the angle θ with respect to a y-axis and right-angled to the x-axis and said scattering beam is received by a beam receiving element 20 through a beam receiving lens 7 and a slit plate 9. Further, the slit of the slit plate 9 is allowed to coincide with the long axis of the oval spot 4a. Since the intensity distribution in the direction of the long axis is made gentle by making laser beam oval and the deviation of the intensity of scattering beam is reduced, the particle size resolving power of fine particles in the liquid specimen can be improved, and a visual field and a focus can be made accurate.
TSUKADA KAZUYA
KAWAKAMI YUKIO
Next Patent: METHOD FOR EXCLUDING STRAY LIGHT OF APPARATUS FOR DETECTING FINE PARTICLE IN LIQUID