# US 7,746,469 B2 · Method for particle size and concentration measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,469 B2 - Document ID: US7746469B2 - Status: Granted - Kind: B2 - Application number: 10/563,662 - Filed: 2004-07-08 - Published: 2008-02-14 - Granted: 2010-06-29 - Earliest claimed: 2003-07-09 - Assignees: P.M.L-Particles Monitoring Technologies, Ltd. - Inventors: Joseph Shamir; Nir Karasikov - Web page: https://patentgrep.com/patent/US7746469B2 ## CPC - G01N 15/1459: {the analysis being performed on a sample stream} - G01N 2015/145: {by pattern of light, e.g. fringe pattern} - G01N 2015/1493: {Particle size} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The present invention provides a system and method of particle size and concentration measurement based on providing a focused, synthesized, non-Gaussian laser beam, causing the beam to interact with the particles, measuring the interaction signal and the number of interactions per unit time of the beam with the particles, and using algorithms to map the interaction signals to the particle size and the number of interactions per unit time to the concentration. The particles are fluid borne, airborne, or on a surface and have a size ranging from sub-micron to thousands of microns. In an embodiment of the invention, the focused, synthesized, non-Gaussian laser beam is a dark beam. The measurements can be made using the duration of interaction with a scanning beam, including dark field. ## Claims ### Claim 1 A method of particle size and concentration measurement comprising the following steps: using one or more lasers to produce a Gaussian laser beam; using means for converting said Gaussian laser beam into a focused, synthesized, non-Gaussian dark beam; causing said particles to flow relative to a stationary dark beam or using a scanning mechanism to cause said beam to interact with said particles; using a detection system to measure the interaction signal and number of interactions per unit time of said dark beam with said particles; and feeding an output of said detection system into a computer comprising algorithms adapted to map said interaction signals to said particle size and said number of interactions per unit time to said concentration. ### Claim 2 (depends on 1) A method according to claim 1, wherein the particles are one of fluid borne, airborne, and on a surface. ### Claim 3 (depends on 1) A method according to claim 1, wherein the size of the particles ranges from sub-micron to thousands of microns. ### Claim 4 (depends on 1) A method according to claim 1, wherein the measurements are made in the intensity domain. ### Claim 5 (depends on 1) A method according to claim 1, wherein the measurements are made using the mapping of the interaction pulse width to particle size. ### Claim 6 (depends on 1) A method according to claim 1, wherein the focal properties of the laser beam are changed depending on the size and concentration range of the particles. ### Claim 7 (depends on 1) A method according to claim 1, wherein the non-Gaussian beam is generated by employing a mask over a Gaussian laser beam. ### Claim 8 (depends on 1) A method according to claim 1, wherein the Gaussian beam is spatially modulated. ### Claim 9 (depends on 8) A method according to claim 8, wherein the Gaussian beam is one of spatially modulated by use of spatial-filter, a set of spatial filters, an electronic spatial light modulator, and a liquid crystal device. ### Claim 10 (depends on 8) A method according to claim 8, wherein the spatial modulation of the Gaussian beam is chosen from the group comprising: (i) intensity modulation; (ii) phase modulation; (iii) wavelength modulation; (iv) polarization modulation; and (v) combinations of these. ### Claim 11 (depends on 8) A method according to claim 8, wherein the spatial modulation is implemented statically. ### Claim 12 (depends on 8) A method according to claim 8, wherein the spatial modulation is implemented dynamically. ### Claim 13 (depends on 1) A method according to claim 1, wherein the non-Gaussian beam is generated by one of directly modifying the laser cavity and combining the beams from several lasers. ### Claim 14 (depends on 1) A method according to claim 1, wherein the interaction of the focused beam with the particles is accomplished by providing the scanning mechanism that provides a linear scanning path for said focused beam. ### Claim 15 (depends on 1) A method according to claim 1, wherein the interaction of the focused beam with the particles is accomplished by providing the scanning mechanism that provides a rotary scanning path for said focused beam. ### Claim 16 (depends on 1) A method according to claim 1, further comprising the use of a second detection system to measure radiation scattered at 90 degrees to the beam direction one of (i) to verify single particle interaction in the focal area and (ii) as an additional dark field information. ### Claim 17 (depends on 16) A method according to claim 16, wherein the second detection system used to measure radiation scattered at 90 degrees to the beam direction comprises a CCD camera. ### Claim 18 (depends on 16) A method according to claim 16, wherein the second detection system used to measure radiation scattered at 90 degrees to the beam direction comprises several detectors. ### Claim 19 (depends on 18) A method according to claim 18, wherein the several detectors are connected in a way selected from the group: addition, differential, and coincidence. ### Claim 20 (depends on 1) A method according to claim 1, wherein the detection system is used to measure radiation back-scattered from the particles. ### Claim 21 (depends on 1) A method according to claim 1, further comprising the use of a detector to measure radiation scattered at 90 degrees to the beam direction to detect smaller particles using dark field TOT measurement. ### Claim 22 (depends on 1) A method according to claim 1, wherein high concentrations of particles are measured by using a reflection, back scatter, mode, collecting the back-scattered interaction energy from the particle. ### Claim 23 (depends on 18) A method according to claim 18, wherein counting interaction signals, of the scanning laser beam, per unit time is used to measure high concentrations of particles. ### Claim 24 (depends on 1) A method according to claim 1, wherein the algorithms adapted to map the interaction signals to the particle size and the number of interactions per unit time to the concentration are explicitly based on said interaction signals. ### Claim 25 (depends on 1) A method according to claim 1, wherein the algorithms adapted to map the interaction signals to the particle size and the number of interactions per unit time to the concentration are based on an advanced artificial intelligence method. ### Claim 26 (depends on 25) A method according to claim 25, wherein the advanced artificial intelligence method is a Neural Network or support vector method (SVM). ### Claim 27 A system for particle size and concentration measurement comprising: one or more lasers to provide a Gaussian laser beam; a scanning mechanism; means for converting said Gaussian laser beam into a focused, synthesized, non-Gaussian laser beam; and detection means; wherein said focused, synthesized, non-Gaussian laser beam is a dark beam and said means for converting said Gaussian laser beam into said focused, synthesized, non-Gaussian laser beam are chosen from the following group: a combination of a spatial filter and a lens; and a liquid crystal device. ### Claim 28 (depends on 27) A system according to claim 27 additionally comprising a second detection system to measure the radiation scattered at 90 degrees to the beam direction. ### Claim 29 (depends on 27) A system according to claim 27, additionally comprising a beam splitter to divert back-scattered interaction energy from the particle to the detection means. ### Claim 30 (depends on 1) A method according to claim 1, wherein the synthesized, non-Gaussian laser beam is circular. ### Claim 31 (depends on 1) A method according to claim 1, wherein the synthesized, non-Gaussian laser beam is linear. ### Claim 32 (depends on 1) A method according to claim 1, wherein the particle size is determined by differential interference of the light scattered from said particle with the two lobes of a linear synthesized, non-Gaussian laser beam. ### Claim 33 (depends on 1) A method according to claim 1, wherein the particle size is determined by analyzing the polarization of the light scattered from said particle. ### Claim 34 (depends on 1) A method according to claim 1, wherein two or more confocal beams are simultaneously generated, each of said beams having a different wavelength.