Patent ID: 8228503

Claim:
An apparatus for detecting a particle in a fluid, the apparatus comprising: a first light source configured to emit a first beam toward the fluid, the first beam having a wavelength of a particular band; a second light source configured to emit a second beam having a wavelength of a band that is different from that of the first beam; a third light source configured to emit a third beam having a wavelength of a band that is different from those of the first beam and the second beam; a first dichroic mirror placed between the fluid and the first light source, the first dichroic mirror configured to allow the first beam to permeate through so as to be directed to the fluid and reflect the second beam and the third beam toward the fluid; a second dichroic mirror placed among the first dichroic mirror, the second light source and the third light source, the second dichroic mirror configured to reflect the second beam toward the first dichroic mirror and allow the third beam to permeate through so as to be directed to the first dichroic mirror; and a detecting unit configured to detect a dispersed beam of the first beam and the second beam and the third beam in the fluid.