US4477187A
Expired / Lapsed
US
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Apparatus and method for sizing particles
Assignee: University Patents Inc
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Filing: 1982-01-25
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Granted: 1984-10-16
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Expires: 2002-01-25
Abstract
Abstract The disclosed invention employs an optical heterodyne technique that depends upon coherent detection of phase modulated light from individual particles, and does not depend on measurement of light scattered at a specific angle from particles. A collimated coherent beam of light is generated and separated into a subject beam and a reference beam. The subject beam is focused at the inspection region and light is gathered from the inspection region. The gathered light and the reference beam are combined and a photodetector is responsive to the combined light for producing an electrical signal representative of the combined light. The phase shift of light scattered from an individual particle passing through the inspection region is then determined by measuring the power in the phase modulated sidebands of the electrical signal. The phase shift is indicative of the size of the particle passing through the inspection region.
Inventors
- 👤 Donald R. Pettit
- 👤 Thomas W. Peterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:35
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/02; G01N15/0205
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
147 words
Apparatus for sizing individual particles passing through an inspection region, comprising: means for generating a collimated coherent beam of light; means for separating said beam into a subject beam and a reference beam; means for focusing the subject beam at the inspection region; means for gathering light from the inspection region; means for combining the gathered light and the reference beam; photodetection means responsive to the combined light for producing an electrical signal representative of the gathered light; means for determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region; and means for counting pulses resulting from said phase shifted sidebands to obtain a count of particles passing through the inspection region.
Claim 2
Dependent Claim
147 words
Apparatus for sizing individual particles passing through an inspection region, comprising: means for generating a collimated coherent beam of light; means for separating said beam into a subject beam and a reference beam; means for focusing the subject beam at the inspection region; means for gathering light from the inspection region; means for combining the gathered light and the reference beam; photodetection means responsive to the combined light for producing an electrical signal representative of the gathered light; means for determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region; and means for counting pulses resulting from said phase shifted sidebands to obtain a count of particles passing through the inspection region.
Claim 3
Dependent Claim
22 words
Apparatus as defined by claim 1 wherein said gathering means is adapted to receive substantially only near-forward light from the inspection region.
Claim 4
Dependent Claim
28 words
Apparatus as defined by claim 1, wherein said focusing means and said gathering means respectively comprise a pair of spaced lenses in the path of the subject beam.
Claim 5
Dependent Claim
28 words
Apparatus as defined by claim 2, wherein said focusing means and said gathering means respectively comprise a pair of spaced lenses in the path of the subject beam.
Claim 6
Independent Claim
127 words
A method for sizing individual particles passing through an inspection region, comprising the steps of: generating a collimated coherent beam of light; separating said beam into a subject beam and reference beam; focusing the subject beam at the inspection region; gathering light from the inspection region; combining the gathered light and the reference beam; producing electrical signals representative of the combined light; determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region; and counting pulses resulting from said phase shifted sidebands to obtain a count of particles passing through the inspection region.
Claim 7
Independent Claim
127 words
A method for sizing individual particles passing through an inspection region, comprising the steps of: generating a collimated coherent beam of light; separating said beam into a subject beam and reference beam; focusing the subject beam at the inspection region; gathering light from the inspection region; combining the gathered light and the reference beam; producing electrical signals representative of the combined light; determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region; and counting pulses resulting from said phase shifted sidebands to obtain a count of particles passing through the inspection region.
Claim 8
Dependent Claim
21 words
The method as defined by claim 5 wherein said gathering step comprises receiving substantially only near-forward light from the inspection region.
Claim 9
Dependent Claim
26 words
The method as defined by claim 5, wherein said focusing and gathering steps employ a pair of spaced lenses in the path of the subject beam.
Claim 10
Dependent Claim
26 words
The method as defined by claim 6, wherein said focusing and gathering steps employ a pair of spaced lenses in the path of the subject beam.
Claim 11
Independent Claim
81 words
A method for sizing particles, comprising the steps of: directing individual particles through an inspection region; generating a collimated coherent beam of light; focusing the beam at the inspection region; gathering light from the inspection region; producing electrical signals representative of the gathered light; and determining, from said electrical signals, the phase shift of light scattered from an individual particle passing through the inspection region, said phase shift being indicative of the size of the particle passing through the inspection region.
Claim 12
Independent Claim
81 words
A method for sizing particles, comprising the steps of: directing individual particles through an inspection region; generating a collimated coherent beam of light; focusing the beam at the inspection region; gathering light from the inspection region; producing electrical signals representative of the gathered light; and determining, from said electrical signals, the phase shift of light scattered from an individual particle passing through the inspection region, said phase shift being indicative of the size of the particle passing through the inspection region.
Claim 13
Dependent Claim
129 words
Apparatus for sizing particles, comprising: means for directing individual particles through an inspection region; means for generating a collimated coherent beam of light; means for separating said beam into a subject beam and a reference beam; means for focusing the subject beam at the inspection region; means for gathering light from the inspection region; means for combining the gathered light and the reference beam; photodetection means responsive to the combined light for producing an electrical signal representative of the gathered light; and means for determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region.
Claim 14
Dependent Claim
129 words
Apparatus for sizing particles, comprising: means for directing individual particles through an inspection region; means for generating a collimated coherent beam of light; means for separating said beam into a subject beam and a reference beam; means for focusing the subject beam at the inspection region; means for gathering light from the inspection region; means for combining the gathered light and the reference beam; photodetection means responsive to the combined light for producing an electrical signal representative of the gathered light; and means for determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region.
Claim 15
Dependent Claim
22 words
Apparatus as defined by claim 10, wherein said gathering means is adapted to receive substantially only near-forward light from the inspection region.
Claim 16
Dependent Claim
28 words
Apparatus as defined by claim 11, wherein said focusing means and said gathering means respectively comprise a pair of spaced lenses in the path of the subject beam.
Claim 17
Dependent Claim
28 words
Apparatus as defined by claim 10 wherein, said focusing means and said gathering means respectively comprise a pair of spaced lenses in the path of the subject beam.
Claim 18
Dependent Claim
29 words
Apparatus as defined by claim 10, further comprising means for counting pulses resulting from said phase shifted sidebands to obtain a count of particles passing through the inspection region.
Claim 19
Independent Claim
110 words
A method for sizing particles, comprising the steps of: directing individual particles through an inspection region; generating a collimated coherent beam of light; separating said beam into a subject beam and a reference beam; focusing the subject beam at the inspection region; gathering light from the inspection region; combining the gathered light and the reference beam; producing electrical signals representative of the combined light; and determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region.
Claim 20
Independent Claim
110 words
A method for sizing particles, comprising the steps of: directing individual particles through an inspection region; generating a collimated coherent beam of light; separating said beam into a subject beam and a reference beam; focusing the subject beam at the inspection region; gathering light from the inspection region; combining the gathered light and the reference beam; producing electrical signals representative of the combined light; and determining the phase shift of light scattered from an individual particle passing through the inspection region by measuring the power in the phase modulated sidebands of said electrical signal, said phase shift being indicative of the size of the particle passing through the inspection region.
Claim 21
Dependent Claim
21 words
The method as defined by claim 15, wherein said gathering step comprises receiving substantially only near-forward light from the inspection region.
Claim 22
Dependent Claim
26 words
The method as defined by claim 16 wherein said focusing and gathering steps employ a pair of spaced lenses in the path of the subject beam.
Claim 23
Dependent Claim
26 words
The method as defined by claim 15, wherein said focusing and gathering steps employ a pair of spaced lenses in the path of the subject beam.
Claim 24
Dependent Claim
31 words
The method as defined by claim 15, further comprising the step of counting pulses resulting from said phase shifted sidebands to obtain a count of particles passing through the inspection region.
References Cited (Backward Citations)
US3539262A
Cited
US4097153A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-16 | 1988-04-16 | 1988-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-16 | 1992-04-16 | 1992-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-16 | 1996-04-16 | 1996-10-16 | $7700.00 | Window Closed / Lapsed |