| 摘要 |
PURPOSE:To enable the handling of a positional deviation along the depth of a light receiving lens between a laser flux and a mask, by providing a detection element on a laser light optical axis to generate an output varying with a deviation in the optical axis after passage through a particle detection area for monitoring. CONSTITUTION:Laser flux 3 is made incident through an incident window 4 so as to condense on a particle measuring area (condensing point) 3a. Scattered light 14 from fine particles 17 in a liquid passing through a condensing point 3a is received with a light receiving window 5 to form an image on a mask 7 with a light receiving lens 6, converted into an electrical signal with a photoelectric converter 8 and a parti cle size is calculated with a pulse height analyzer 9 from intensity of the scattered light to display 10. The laser flux 3 once condensed is emitted out of a measuring cell 20 through an emission window 11 diverging to be incident into a beam split cube 42 and mostly transmitted through to be absorbed by a light trap 12. The lumi nous flux divided with the cube 42 forms an image on a semiconductor position detecting element 46 with an imaging lens 44. A signal from the element 46 is inputted into a circuit for detecting a deviation in the optical axis and the deviation is displayed with an LED or the like when exceeding an allowable range.
|
