Device and process for interferometric sizing of particles using spatial filtering of scattered radiation
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Nov 4, 1997
Grant Date -
N/A
app pub date -
Jul 5, 1996
filing date -
Jul 5, 1996
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
An apparatus for non-contact measurement of particles, fibers and other light scattering elements includes two laser beams that intersect one another to form a measuring region within a composite flow. Particles in the flow scatter the laser energy as they traverse the measuring region. Scattered energy is received by a pair of optical detectors that generate respective electrical signals based on received energy. The detectors have selectively contoured non-rectangular apertures to controllably vary transmittance and as a result generate phase differences according to a corresponding non-linear function that relates the phase differences to particle diameters. One particularly effective aperture shape includes opposite sides contoured according to a lognormal function, to resemble an onion or tear drop. Triangular and trapezoidal apertures also can be used to achieve non-linear functions. In alternative embodiments, rectangular apertures are used in combination with energy attenuation filters with selective gradients in thickness or transmissivity. The result is a selected variance of transmittance in the detector similar to that achieved by controlling the aperture shape.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully