Method and apparatus for timing of laser beams in a multiple laser beam fusion system
Automated method for cell volume determination
Apparatus for sizing particles, droplets or the like with laser scattering
Optical particle analyzers
Particle size measuring method and apparatus
Device for measuring particles in a fluid Patent #: 4444500
ApplicationNo. 06/643665 filed on 08/22/1984
US Classes:356/336, By particle light scattering356/338With photocell detection
ExaminersPrimary: Willis, Davis L.
Assistant: Koren, Matthew W.
Attorney, Agent or Firm
International ClassesG01N 15/02 (20060101)
G01N 15/14 (20060101)
G01N 21/21 (20060101)
AbstractParticle measurement is disclosed utilizing orthogonally polarized components of a laser beam. A laser beam is split into orthogonally polarized components and at least one of the components is thereafter beam shaped to have a modified dimension. The components are then recombined and focused to provide a beam combination that is directed through a particle containing volume where scattering of the components occurs by the particles. With the components superimposed upon one another, a localized volume is created with one beam being contracted to a smaller volume than the other beam with the illumination intensity ratios thereat being either greater or less than unity depending upon the optics selected. Particle scattering events are observed within the localized volume in order to define those particles transitting through its central uniform intensity region (sample volume) independent of viewing circumstance by comparing scattered intensity ratios of the orthogonally polarized beam components using a polarizing analyzer and a pair of detectors. The scattering intensities measured of those particles transitting through the preferred sample volume are retained as valid size measurements. With the components in juxtaposition with respect to one another, flow velocity measurement is enabled by measurement of the transit times between the juxtapositioned components.