Patent ID: 6281973
Filing Date: 2001-08-28
Classification: G01N

Abstract:
An optical detection system used in determining the size distribution of particles contained in a dispersant medium, said optical detection system comprising:a light source for producing light energy;a first light guide for conveying said light energy from said light source to a first light guide face end, said light guide face end immersed in said dispersant medium, whereby a first portion of said light energy exits said face end to irradiate the particles contained in said dispersant medium and a second portion of said light energy is reflected from said face end back into said first light guide;a frequency oscillator for producing at least one signal representing a specific frequency within a frequency range;a frequency transducer coupled with said first light guide and connected to said frequency oscillator, said frequency transducer operable to receive said frequency oscillator signal and to oscillate said first light guide face end and said dispersant medium at the specific frequency, said particles contained in said dispersant medium oscillating at the oscillation frequency of said first light guide face end;said first light guide face end capturing the light energy scattered by the particles that are oscillating at the oscillation frequency of said first light guide face end, said captured light energy and said reflected light energy mixing within the first light guide and producing an optical Doppler beat signal for the applied specific frequency; anda second light guide optically coupled to said first light guide for conveying said optical Doppler beat signal to a light detection device, said light detection device producing an output signal representative of said optical Doppler beat signal.