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US4975237A Expired / Lapsed US ⏱️ 0.0 years remaining

Dynamic light scattering apparatus

Assignee: Qinetiq Ltd
•
Filing: 1989-07-17
•
Granted: 1990-12-04
•
Expires: 2009-07-17
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Abstract

Abstract A dynamic light scattering apparatus (10) comprises a laser (12) optically coupled to a light scattering sample (26) via a first monomode optical fibre (18) and a first lens (22). The lens (22) produces a beam waist (24) in the sample (26), and scattered light is collected by a receive lens (30) and a second monomode optical fibre (34). The second fibre (34) has an end face in the Fourier plane (84) of the receive lens (30, 70), and defines an aperture matched to a single Airy disc (82) of the lens (30, 70). The receive fibre (34) accordingly receives a single spatial mode of light scattered from the sample (26), this mode corresponding to a single plane wave to which many scatterers contribute. The receive fibre (34) also attenuates unwanted spatial modes because of its monomode character. A photodetector (36) detects light transmitted by the receive fibre (34).

Inventors

  • 👤 Robert G. W. Watling

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 06:03
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/02; G01J3/0205; G01J3/0208; G01J3/0218; G01J3/0221; G01J3/28; G01J3/44; G01J3/4412; G01P; G01P5/00; G01P5/26; G01N; G01N15/00; G01N15/02; G01N15/0205; G01N15/0211; G01N2015/0216; G01N2015/0222; G01N15/10; G01N15/14; G01N15/1434; G01N2015/1447; G01N2015/145; G01N21/00; G01N21/17; G01N21/47; G01N21/4738; G01N21/474; G01N2021/4742; G01N21/4788; G01N2021/479; G01N21/49; G01N21/53

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 70 words
A dynamic light scattering apparatus comprising a laser (12) arranged to produce a laser beam (24) in a fluid scattering volume (26), and means (28 to 36) for collecting and detecting light scattered from the scattering volume (26), characterised in that the apparatus (10) also includes means (30, 34) for spatially Fourier transforming light scattered from the scattering volume (26) and for isolating a single spatial mode thereof for detection.
Claim 2
Dependent Claim 70 words
A dynamic light scattering apparatus comprising a laser (12) arranged to produce a laser beam (24) in a fluid scattering volume (26), and means (28 to 36) for collecting and detecting light scattered from the scattering volume (26), characterised in that the apparatus (10) also includes means (30, 34) for spatially Fourier transforming light scattered from the scattering volume (26) and for isolating a single spatial mode thereof for detection.
Claim 3
Dependent Claim 46 words
A dynamic light scattering apparatus according to claim 1 characterised in that the Fourier transforming and isolating means comprises focussing means (30) and aperture defining means (34) arranged to transmit light from a single Airy disc (82) of the focussing means (30) to detecting means (36).
Claim 4
Dependent Claim 41 words
An apparatus according to claim 2 characterised in that the focussing means comprises a lens (30) and the aperture defining means comprises an end face of a monomode optical fibre (34), the fibre (34) being arranged to attenuate unwanted spatial modes.
Claim 5
Dependent Claim 31 words
An apparatus according to claim 1 characterised in that it includes monomode fibre optic coupling means (176) arranged to mix scattered and unscattered laser light as required for light beating measurements.
Claim 6
Dependent Claim 32 words
An apparatus according to claim 1 characterised in that the laser (224) and the Fourier transforming and isolating means (228, 230, 232) are produced by integrated techniques on a common support (222).
Claim 7
Dependent Claim 40 words
An apparatus according to claim 5 characterised in that the Fourier transforming and isolating means (228, 230, 232) comprises a lens (232) and a photodiode (226) arranged to receive light from a single Airy disc (82) of the lens (232).

References Cited (Backward Citations)

FR2122034A5 Cited
US4150360A Cited
EP0106684A2 Cited
US4762413A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-12-03 1994-06-04 1994-12-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-12-03 1998-06-04 1998-12-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-12-03 2002-06-04 2002-12-04 $7700.00 Window Closed / Lapsed

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