US4917494A
Expired / Lapsed
US
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Beam forming apparatus for aerodynamic particle sizing system
Assignee: TSI Inc
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Filing: 1988-09-09
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Granted: 1990-04-17
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Expires: 2008-09-09
Abstract
Abstract Apparatus, intended primarily for use in an aerodynamic particle sizing system, for generating a pair of closely-spaced light beams, each having a thin, elongated cross-sectional shape. Particle sizes are determined by directing a particle stream through the light beams and measuring the times of flight of particles between the two light beams. The apparatus for generating the light beams includes a laser source and beam forming optics. In one embodiment, a first light beam is formed at the particle stream by a cylindrical lens. After passing through the particle stream, the first light beam is reflected and focused to form a second light beam at the particle stream that is displaced from the first light beam. The first light beam can be reflected and focused by a concave cylindrical mirror or, alternatively, by a flat mirror and a convex cylindrical lens. In another embodiment, the incident light beam from the laser source is passed through a diffraction grating which provides a zero order lobe and a first order lobe. The zero order lobe and the first order lobe are focused at a particle stream by a cylindrical lens to form the first and second beams.
Inventors
- 👤 Trent A. Poole
- 👤 Norman C. Ford
- 👤 Barton E. Dahneke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:34
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/10; G01N15/14; G01N15/1434; G01N15/1456; G01N15/1459; G02; G02B; G02B27/00; G02B27/10; G02B27/1073; G02B27/1086; G02B27/14; G02B27/143; G01N15/02; G01N15/0205; G01N2015/0238; G01N2015/1447
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
118 words
Apparatus for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, comprising: source means for generating an incident light beam; means defining an aperture slit; first lens means for focusing the incident light beam on said slit defining means; second lens means positioned for focusing an image of said aperture slit in said image plane to form said first light beam; and optical means for reflecting said first light beam after passing through said image plane to form a reflected first light beam and for focusing said reflected first light beam in said image plane to form said second light beam spaced from said first light beam.
Claim 2
Dependent Claim
118 words
Apparatus for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, comprising: source means for generating an incident light beam; means defining an aperture slit; first lens means for focusing the incident light beam on said slit defining means; second lens means positioned for focusing an image of said aperture slit in said image plane to form said first light beam; and optical means for reflecting said first light beam after passing through said image plane to form a reflected first light beam and for focusing said reflected first light beam in said image plane to form said second light beam spaced from said first light beam.
Claim 3
Dependent Claim
30 words
Apparatus as defined in claim 1 wherein said optical means comprises a concave cylindrical mirror having an axis lying in said image plane between said first and second light beams.
Claim 4
Dependent Claim
47 words
Apparatus as defined in claim 2 further comprising adjustment means for adjusting the spacing between said first and second light beams, said adjustment means including means for displacing said cylindrical mirror parallel to said image plane in a direction perpendicular to the axis of said cylindrical mirror.
Claim 5
Dependent Claim
15 words
Apparatus as defined in claim 1 wherein said second lens means comprises a cylindrical lens.
Claim 6
Dependent Claim
15 words
Apparatus as defined in claim 1 wherein said first lens means comprises a cylindrical lens.
Claim 7
Dependent Claim
35 words
Apparatus as defined in claim 1 wherein said optical means comprises a flat mirror and a convex cylindrical lens, said lens being spaced from said image plane by a distance equal to its focal length.
Claim 8
Dependent Claim
51 words
Apparatus as defined in claim 6 further comprising adjustment means for adjusting the spacing between said first and second light beams, said adjustment means including means for displacing said flat mirror and said cylindrical lens parallel to said image plane in a direction perpendicular to the axis of said cylindrical lens.
Claim 9
Dependent Claim
21 words
Apparatus as defined in claim 1 further including means for absorbing said second light beam after passing through said image plane.
Claim 10
Dependent Claim
40 words
Apparatus as defined in claim 8 wherein said absorbing means comprises a prism located adjacent to said aperture slit for deflecting said second light beam and a beam absorber for intercepting said second light beam after deflection by said prism.
Claim 11
Dependent Claim
13 words
Apparatus as defined in claim 1 wherein said source means comprises a laser.
Claim 12
Dependent Claim
96 words
Apparatus for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, comprising: source means for generating an incident light beam; a cylindrical lens for focusing said incident light beam in said image plane to form said first light beam; and optical means for reflecting said first light beam after passing through said image plane to form a reflected first light beam and for focusing said reflected first light beam in said image plane to form said second light beam spaced from said first light beam.
Claim 13
Dependent Claim
96 words
Apparatus for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, comprising: source means for generating an incident light beam; a cylindrical lens for focusing said incident light beam in said image plane to form said first light beam; and optical means for reflecting said first light beam after passing through said image plane to form a reflected first light beam and for focusing said reflected first light beam in said image plane to form said second light beam spaced from said first light beam.
Claim 14
Dependent Claim
30 words
Apparatus as defined in claim 11 wherein said optical means comprises a concave cylindrical mirror having an axis lying in said image plane between said first and second light beams.
Claim 15
Dependent Claim
47 words
Apparatus as defined in claim 12 further comprising adjustment means for adjusting the spacing between said first and second light beams, said adjustment means including means for displacing said cylindrical mirror parallel to said image plane in a direction perpendicular to the axis of said cylindrical mirror.
Claim 16
Dependent Claim
35 words
Apparatus as defined in claim 11 wherein said optical means comprises a flat mirror and a convex cylindrical lens, said lens being spaced from said image plane by a distance equal to its focal length.
Claim 17
Dependent Claim
51 words
Apparatus as defined in claim 14 further comprising adjustment means for adjusting the spacing between said first and second light beams, said adjustment means including means for displacing said flat mirror and said cylindrical lens parallel to said image plane in a direction perpendicular to the axis of said cylindrical lens.
Claim 18
Dependent Claim
21 words
Apparatus as defined in claim 11 further including means for absorbing said second light beam after passing through said image plane.
Claim 19
Independent Claim
102 words
A method for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, said method comprising the steps of: generating an incident light beam; focusing the incident light beam on an aperture slit; focusing an image of said aperture slit in said image plane to form said first light beam; reflecting said first light beam after it passes through said image plane to form a reflected first light beam; and focusing said reflected first light beam in said image plane to form said second light beam spaced from said first light beam.
Claim 20
Independent Claim
102 words
A method for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, said method comprising the steps of: generating an incident light beam; focusing the incident light beam on an aperture slit; focusing an image of said aperture slit in said image plane to form said first light beam; reflecting said first light beam after it passes through said image plane to form a reflected first light beam; and focusing said reflected first light beam in said image plane to form said second light beam spaced from said first light beam.
Claim 21
Dependent Claim
192 words
A particle sizing system comprising: an evacuated measurement chamber; means for directing a stream of particles to be measured through said measurement chamber; beam generating means for directing closely-spaced first and second light beams through said particle stream, each light beam having a thin cross-section along the direction of said particle stream and having an elongated cross-section in a direction perpendicular to said particle stream, said beam generating means including source means for generating an incident light beam, means defining an aperture slit, first lens means for focusing the incident light beam on said slit defining means, second lens means positioned for focusing an image of said aperture slit at said particle stream to form said first light beam, and optical means for reflecting said first light beam after passing through said particle stream to form a reflected first light beam and for focusing said reflected first light beam at said particle stream to form said second light beam spaced from said first light beam; and means for measuring particle sizes based on the times of flight of particles in said particle stream between said first light beam and said second beam.
Claim 22
Dependent Claim
192 words
A particle sizing system comprising: an evacuated measurement chamber; means for directing a stream of particles to be measured through said measurement chamber; beam generating means for directing closely-spaced first and second light beams through said particle stream, each light beam having a thin cross-section along the direction of said particle stream and having an elongated cross-section in a direction perpendicular to said particle stream, said beam generating means including source means for generating an incident light beam, means defining an aperture slit, first lens means for focusing the incident light beam on said slit defining means, second lens means positioned for focusing an image of said aperture slit at said particle stream to form said first light beam, and optical means for reflecting said first light beam after passing through said particle stream to form a reflected first light beam and for focusing said reflected first light beam at said particle stream to form said second light beam spaced from said first light beam; and means for measuring particle sizes based on the times of flight of particles in said particle stream between said first light beam and said second beam.
Claim 23
Dependent Claim
32 words
A particle sizing system as defined in claim 18 wherein said optical means comprises a concave cylindrical mirror having an axis intersecting said particle stream between said first and second light beams.
Claim 24
Dependent Claim
50 words
A particle sizing system as defined in claim 18 wherein said optical means comprises a flat mirror and a convex cylindrical lens, said lens being spaced from said particle stream by a distance equal to its focal length, and the axis of said lens being perpendicular to said particle stream.
Claim 25
Dependent Claim
42 words
A particle sizing system as defined in claim 18 further comprising adjustment means for adjusting the spacing between said first and second light beams, said adjustment means including means for displacing said optical means along a line parallel to said particle stream.
Claim 26
Dependent Claim
110 words
Apparatus for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, comprising: source means for generating an incident light beam; a diffraction grating positioned to convert a portion of the incident light beam into diffracted beams in a zero order lobe and at least one first order lobe; and a cylindrical lens spaced from said diffraction grating for focusing said zero order lobe and said at least one first order lobe into said first and second light beams, respectively, said cylindrical lens being spaced from said diffraction grating such that said first and second light beams are substantially parallel.
Claim 27
Dependent Claim
110 words
Apparatus for generating closely-spaced first and second light beams in an image plane, each light beam having a thin, elongated cross-sectional shape, comprising: source means for generating an incident light beam; a diffraction grating positioned to convert a portion of the incident light beam into diffracted beams in a zero order lobe and at least one first order lobe; and a cylindrical lens spaced from said diffraction grating for focusing said zero order lobe and said at least one first order lobe into said first and second light beams, respectively, said cylindrical lens being spaced from said diffraction grating such that said first and second light beams are substantially parallel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |