US 4,286,876 AGranted

Apparatus and method for measuring scattering of light in particle detection systems

AssigneeCoulter Electronics, Inc.

InventorsWalter R. Hogg, Albert Brunsting

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Abstract

In an apparatus in which particles are passed through an optical sensing zone to measure their light scattering characteristics for the purpose of identifying the particles, means and a method are provided for deviating the collected light in accordance with predetermined different paths to a plurality of different photodetecting devices. The deviation is effected simultaneously with collection by optical radiant energy reflecting means. The different photodetecting devices enable the measurement of energy scattered along the particular path which is identified with that device. The paths are established by the combined collecting and deviating means rather than permitted to evolve by the scattering phenomena themselves whereby the photodetecting devices can be located in convenient arrangements and may be conventional in construction.

Claims30

Dependent claims

Apparatus for measuring the scattering of radiant energy produced by particles for identification or the like of the said particles which comprises:

A. a source of radiant energy arranged to project a beam of radiant energy along a path,
B. a sensing zone,
C. means for moving particles through said sensing zone on an angle relative to said path to produce scattering of radiant energy from said beam,
D. combined collecting and deviating means for receiving some of the scattered radiant energy and reflecting the same selectively with respect to different geometric portions of the scattered energy to confluence points at locations laterally spaced from said first axis, said collecting and deviating means comprising
i. an assembly of spherical mirror elements having their reflective surfaces facing the sensing zone, said assembly having a central first axis passing through said sensing zone,
ii. each element being of a configuration and location to receive and collect radiant energy from a different geometric portion,
iii. each element having an optical second axis, said element being oriented with respect to the first axis such that its own optical second axis diverges from the said first axis such that it deviates the radiant energy it collects by reflection along a third reflective axis which is twice the angle between the first and second axes to a point of confluence of the deviated radiant energy that is spaced laterally from the first axis,
iv. the confluence point locations being spaced apart from one another in addition to being spaced laterally from the first axis and
E. means responsive to the intensity of radiant energy at each location.

6 more elements

A method of measuring the directional distribution properties of a particle for particle identification or the like which comprises:

A. passing the particle through a sensing zone and illuminating the particle with an incident beam of radiant energy whereby to produce reactive directional distribution of the radiant energy as a result of the intersection of particle and beam,
B. intercepting a portion of the radiant energy which is directionally distributed and which is projected to the location of interception in a conical solid angle whose approximate principal optical axis extends between the point of intersection and the location of interception,
C. reflecting the intercepted radiant energy along a plurality of different paths which diverge from the principal axis and confluence at locations laterally of the axis,
i. each path being arranged to comprise the radiant energy intercepted from an arcuate solid angle of the projected portion,
ii. the arcuate areas being different from one another,
iii. the axis of each path being a reflective axis
iv. the locations of confluence being spaced from one another, and
D. measuring the respective intensities of the radiant energy at the locations of confluence.

5 more elements

Dependencies are inferred from the claim text.