US4854705A — Method and apparatus to determine the size and ve…

Claim 1

Independent Claim 309 words

An apparatus employing laser light scattering for determining the size of a particle, comprising: laser beam generation means for generating first and second laser beams having Gaussian beam intensities; beam expansion means in optical alignment with said first laser beam for expanding the diameter of said first beam; light directing means for directing said first and second beams and combining said beams such that said second beam is disposed within and coaxial with said first beam; focussing means in optical alignment with said light directing means for focussing said first and second beams such that they converge and said first beam is disposed within and coaxial with said second beam, thereby forming a sample volume; collection means for sensing light scattered by a particle passing through said sample volume, said collection means converting said scattered light into electrical signals; amplitude means coupled to said collection means for determining the amplitude of said electrical signals representing said scattered light; trajectory determining means coupled to said amplitude means for calculating the trajector (x p ) of a particle passing through said sample volume, said trajectory being defined by: ##EQU7## where: x p =distance from the center of said second beam in said sample volume; b 1 =distance from the maximum intensity of said second beam in said sample volume; b 2 =distance from the maximum intensity of said first beam in said sample volume; I o1 =peak intensity of said first beam; I 02 =peak intensity of said second beam; I sca1 =scattered light intensity of said first beam; I sca2 =scattered light intensity of said second beam; Q 1 =scattering parameter of said first beam; Q 2 =scattering parameter of said second beam; sizing means coupled to said trajectory determining means for determining the diameter of said particle from said particle's trajectory; whereby the size of said particle is determined.

Claim 2

Independent Claim 309 words

An apparatus employing laser light scattering for determining the size of a particle, comprising: laser beam generation means for generating first and second laser beams having Gaussian beam intensities; beam expansion means in optical alignment with said first laser beam for expanding the diameter of said first beam; light directing means for directing said first and second beams and combining said beams such that said second beam is disposed within and coaxial with said first beam; focussing means in optical alignment with said light directing means for focussing said first and second beams such that they converge and said first beam is disposed within and coaxial with said second beam, thereby forming a sample volume; collection means for sensing light scattered by a particle passing through said sample volume, said collection means converting said scattered light into electrical signals; amplitude means coupled to said collection means for determining the amplitude of said electrical signals representing said scattered light; trajectory determining means coupled to said amplitude means for calculating the trajector (x p ) of a particle passing through said sample volume, said trajectory being defined by: ##EQU7## where: x p =distance from the center of said second beam in said sample volume; b 1 =distance from the maximum intensity of said second beam in said sample volume; b 2 =distance from the maximum intensity of said first beam in said sample volume; I o1 =peak intensity of said first beam; I 02 =peak intensity of said second beam; I sca1 =scattered light intensity of said first beam; I sca2 =scattered light intensity of said second beam; Q 1 =scattering parameter of said first beam; Q 2 =scattering parameter of said second beam; sizing means coupled to said trajectory determining means for determining the diameter of said particle from said particle's trajectory; whereby the size of said particle is determined.

Claim 3

Dependent Claim 41 words

The apparatus as defined by claim 1, wherein said I sca1 and I sca2 values are determined by said trajectory determining means from the expressions: I.sub.sca1 =I.sub.o1 Q.sub.1 (d) exp [-2x.sub.p.sup.2 /b.sub.1.sup.2 ] I.sub.sca2 =I.sub.o2 Q.sub.2 (d) exp [-2x.sub.p.sup.2 /b.sub.2.sup.2 ].

Claim 4

Dependent Claim 57 words

The apparatus as defined by claim 2, wherein said sizing means includes look-up table means for relaing said Q 1 (d) and Q 2 (d) values to said particle diameter (d), such that inputting said Q 1 (d) and Q 2 (d) values into said look-up table means results in an output corresponding to a diameter (d).

Claim 5

Dependent Claim 28 words

The apparatus as defined by claim 3, further including speed means coupled to said amplitude means for determining the speed of said particle passing through said sample volume.

Claim 6

Dependent Claim 40 words

The apparatus as defined by claim 4, wherein said collection means includes first and second photo-detectors for sensing light scattered by said particle through each of said first and second beams, respectively, said photo-detectors being coupled to said amplitude means.

Claim 7

Dependent Claim 48 words

The apparatus as defined by claim 5, wherein said photo-detectors sense said scattered light once said light exceeds a threshold value defined as: T=Q.sub.1 (d)I.sub.o1 exp [-2x.sub.t.sup.2 /b.sub.1.sup.2 ] where: T=threshold value; x t =beam radius at the intensity level which produces a signal at said threshold level.

Claim 8

Dependent Claim 37 words

The apparatus as defined by claim 6, wherein the path length of said particle between where said electrical signals exceeds said threshold levels to where said signals fall below said level is defined as: I=2[x.sub.t.sup.2 -x.sub.p.sup.2 ].sup.1/2.

Claim 9

Dependent Claim 32 words

The apparatus as defined by claim 7, wherein said speed means determines the time t when said signal exceeds said threshold value, the speed(s) of said particle being defined as: X=x.sub.t /t.

Claim 10

Dependent Claim 68 words

The apparatus as defined by claim 8, wherein said speed means further determines the number of density of particles passing through said sample volume from the expression: ##EQU8## where: N=number density of said particles; n i (d)=number of particles in each size class i of M size classes; A i (d)=sample cross-section area for particle class size d; S i (d)=speed of said particle in size class d.

Claim 11

Independent Claim 344 words

An apparatus employing laser light scattering for determining the size of a particle, comprising: laser beam generation means for generating first and second laser beams hving Gaussian beam intensities; beam expansion and splitting means in optical alignment with said first laser beam for expanding the diameter of said first beam and splitting said first beam into at least two parallel coplaner beams disposed in a first plane; polarization and beam splitting means in optical alignment with said second beam and splitting said second beam into at least two parallel coplanar beams disposed in a second plane; light detecting means for directing said first and second beam such that said first plane is disposed approximately at a known angle with respect to said second plane; focussing means in optical alignment with said light directing means for focussing said first and second beams such that they converge thereby forming a sample volume; collection means for sensing light scattered by a particle passing through said sample volume, said collection means converting said scattered light into electrical signals; amplitude means coupled to said collection means for determining the amplitude of said electrical signals representing said scattered light; trajectory determining means coupled to said amplitude means for calculating the trajectory (x p ) of a particle passing through said sample volume, said trajectory being defined by: ##EQU9## where: x p =distance from the center of said second beam in said sample volume; b 1 =distance from the maximum intensity of said second beam in said sample volume; b 2 =distance from the maximum intensity of said first beam in said sample volume; I o1 =peak intensity of said first beam; I 02 =peak intensity of said second beam; I sca1 =scattered light intensity of said first beam; I sca2 =scattered light intensity of said second beam; Q 1 =scattering parameter of said first beam; Q 2 =scattering parameter of said second beam; sizing means coupled to said trajectory determining means for determining the diameter of said particle from said particle's trajectory; whereby the size of said particle is determined.

Claim 12

Independent Claim 344 words

An apparatus employing laser light scattering for determining the size of a particle, comprising: laser beam generation means for generating first and second laser beams hving Gaussian beam intensities; beam expansion and splitting means in optical alignment with said first laser beam for expanding the diameter of said first beam and splitting said first beam into at least two parallel coplaner beams disposed in a first plane; polarization and beam splitting means in optical alignment with said second beam and splitting said second beam into at least two parallel coplanar beams disposed in a second plane; light detecting means for directing said first and second beam such that said first plane is disposed approximately at a known angle with respect to said second plane; focussing means in optical alignment with said light directing means for focussing said first and second beams such that they converge thereby forming a sample volume; collection means for sensing light scattered by a particle passing through said sample volume, said collection means converting said scattered light into electrical signals; amplitude means coupled to said collection means for determining the amplitude of said electrical signals representing said scattered light; trajectory determining means coupled to said amplitude means for calculating the trajectory (x p ) of a particle passing through said sample volume, said trajectory being defined by: ##EQU9## where: x p =distance from the center of said second beam in said sample volume; b 1 =distance from the maximum intensity of said second beam in said sample volume; b 2 =distance from the maximum intensity of said first beam in said sample volume; I o1 =peak intensity of said first beam; I 02 =peak intensity of said second beam; I sca1 =scattered light intensity of said first beam; I sca2 =scattered light intensity of said second beam; Q 1 =scattering parameter of said first beam; Q 2 =scattering parameter of said second beam; sizing means coupled to said trajectory determining means for determining the diameter of said particle from said particle's trajectory; whereby the size of said particle is determined.

Claim 13

Dependent Claim 41 words

The apparatus as defined by claim 10, wherein said I sca1 and I sca2 values are determined by said trajectory determining means from the expressions: I.sub.sca1 =I.sub.o1 Q.sub.1 (d) exp [-2x.sub.p.sup.2 /b.sub.1.sup.2 ] I.sub.sca2 =I.sub.o2 Q.sub.2 (d) exp [-2x.sub.p.sup.2 /b.sub.2.sup.2 ].

Claim 14

Dependent Claim 57 words

The apparatus as defined by claim 11, wherein said sizing means includes look-up table means for relating said Q 1 (d) and Q 2 (d) values to said particle diameter (d), such that inputting said Q 1 (d) and Q 2 (d) values into said look-up table means results in an output corresponding to a diameter (d).

Claim 15

Dependent Claim 28 words

The apparatus as defined by claim 12, further including speed means coupled to said amplitude means for determining the speed of said particle passing through said sample volume.

Claim 16

Dependent Claim 40 words

The apparatus as defined by claim 13, wherein said collection means includes first and second photo-detectors for sensing light scattered by said particle through each of said first and second beams, respectively, said photo-detectors being coupled to said amplitude means.

Claim 17

Dependent Claim 48 words

The apparatus as defined by claim 14, wherein said photo-detectors sense said scattered light once said light exceeds a threshold value defined as: T=Q.sub.1 (d)I.sub.o1 exp [-2x.sub.t.sup.2 /b.sub.1.sup.2 ] where: T=threshold value; x t =beam radius at the intensity level which produces a signal at said threshold level.

Claim 18

Dependent Claim 37 words

The apparatus as defined by claim 15, wherein the path length of said particle between where said electrical signals exceeds said threshold levels to where said signals fall below said level is defined as: I=2[x.sub.t.sup.2 -x.sub.p.sup.2 ].sup.1/2.

Claim 19

Dependent Claim 22 words

The apparatus as defined by claim 16, wherein said speed means determines the two orthogonal velocity components using a laser Doppler velocimeter.

Claim 20

Dependent Claim 13 words

The apparatus as defined by claim 17, wherein said known angle is 90°.

Claim 21

Dependent Claim 67 words

The apparatus as defined by claim 17, wherein said speed means further determines the number density of particles passing through said sample volume from the expression: ##EQU10## where: N=number density of said particles; n i (d)=number of particles in each size class i of M size classes; A i (d)=sample cross-section area for particle class size d; S i (d)=speed of said particle in size class d.

Claim 22

Independent Claim 238 words

A method employing laser light scattering for determining the size and trajectory of a particle comprising the steps of generating first and second laser beams having Gaussian beam intensities; expanding the diameter of said first beam; directing said first and second combining said beams such that said second beam is disposed within and coaxial with said first beam; focussing said first and second beam such that they converge, thereby forming a sample volume; sensing light scattered by a particle passing through said sample volume, and converting said scattered light into electrical signals; determining the amplitude of said electrical signals representing said scattered light; determining the trajectory (x p ) of a particle passing through said sample volume, said trajectory being defined by ##EQU11## where: x p =distance from the center of said second beam in said sample volume; b 1 =distance from the maximum intensity of said first beam in said sample volume; b 2 =distance from the maximum intensity of said second beam in said sample volume; I o1 =peak intensity of said first beam; I 02 =peak intensity of said second beam; I sca1 =scattered light intensity of said first beam; I sca2 =scattered light intensity of said second beam; Q 1 =scattering parameter of said first beam; Q 2 =scattering parameter of said second beam; determining the diameter of said particle from said particle's trajectory; whereby the size and trajectory of said particle is determined.

Claim 23

Independent Claim 238 words

A method employing laser light scattering for determining the size and trajectory of a particle comprising the steps of generating first and second laser beams having Gaussian beam intensities; expanding the diameter of said first beam; directing said first and second combining said beams such that said second beam is disposed within and coaxial with said first beam; focussing said first and second beam such that they converge, thereby forming a sample volume; sensing light scattered by a particle passing through said sample volume, and converting said scattered light into electrical signals; determining the amplitude of said electrical signals representing said scattered light; determining the trajectory (x p ) of a particle passing through said sample volume, said trajectory being defined by ##EQU11## where: x p =distance from the center of said second beam in said sample volume; b 1 =distance from the maximum intensity of said first beam in said sample volume; b 2 =distance from the maximum intensity of said second beam in said sample volume; I o1 =peak intensity of said first beam; I 02 =peak intensity of said second beam; I sca1 =scattered light intensity of said first beam; I sca2 =scattered light intensity of said second beam; Q 1 =scattering parameter of said first beam; Q 2 =scattering parameter of said second beam; determining the diameter of said particle from said particle's trajectory; whereby the size and trajectory of said particle is determined.

Claim 24

Dependent Claim 41 words

The method as defined by claim 20, wherein said I sca1 and I sca2 values are determined by said trajectory determining means from the expressions: I.sub.sca1 =I.sub.o1 Q.sub.1 (d) exp [-2x.sub.p.sup.2 /b.sub.1.sup.2 ] I.sub.sca2 =I.sub.o2 Q.sub.2 (d) exp [-2x.sub.p.sup.2 /b.sub.2.sup.2 ].

Claim 25

Dependent Claim 61 words

The method as defined by claim 20, wherein said size of said particle is determined using look-up table means for relating said Q 1 (d) and Q 2 (d) values to said particle diameter d such that inputting said Q 1 (d) and Q 2 (d) values into said look-up table means results in an output corresponding to a diameter d.

Claim 26

Dependent Claim 23 words

The method as defined by claim 21, further including the step of determining the speed of said particle passing through said sample volume.

Claim 27

Dependent Claim 19 words

The method as defined by claim 22, wherein said sensing step includes the use of first and second photodetectors.

Claim 28

Dependent Claim 40 words

The method as defined by claim 23, wherein said collection means includes first and second photo-detectors for sensing light scattered by said particle through each of said first and second beams, respectively, said photo-detectors being coupled to said amplitude means.

Claim 29

Dependent Claim 48 words

The method as defined by claim 24, wherein said photo-detectors sense said scattered light once said light exceeds a threshold value defined as: T=Q.sub.1 (d)I.sub.o1 exp [-2x.sub.t.sup.2 /b.sub.1.sup.2 ] where: T=threshold value; x t =beam radius at the intensity level which produces a signal at said threshold level.

Claim 30

Dependent Claim 37 words

The method as defined by claim 25, wherein the path length of said particle between where said electrical signals exceeds said threshold levels to where said signals fall below said level is defined as: I=2[x.sub.t.sup.2 -x.sub.p.sup.2 ].sup.1/2.

Claim 31

Dependent Claim 32 words

The method as defined by claim 26, wherein said speed means determines the time t when said signal exceeds said threshold value, the speed(s) of said particle being defined as: S=x.sub.t /t.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-08-07	1993-02-06	1993-08-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-08-07	1997-02-06	1997-08-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-08-07	2001-02-06	2001-08-08	$7700.00	Window Closed / Lapsed

Method and apparatus to determine the size and velocity of particles using light scatter detection from confocal beams

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