Abstract: The present invention relates to an instrument for determining the light scattered by a sample comprising a platform rotatable about an axis of rotation; a sample holder disposed along the axis of rotation; a light source for producing a beam of coherent light that can be focused on a sample in the sample holder; and a plurality of detectors disposed and rotatable about the axis of rotation and adapted so that each detector can be adjusted to focus on a common point along the axis of rotation by reference to the beam.

Abstract: Arrangement for generating well-defined beam distribution over a surface or in a volume by means of a diffraction optical element (17). The arrangement includes at least one laser source (14), an optical filter means, preferably a mode-selective filter (16), a diffraction optical component (17) as well as possible coupling and focusing elements (15, 18). Said components, means and elements are positioned and fixed in a common unit and that the filter (16) is so developed that the beam from the source (14) after passage through said mode-selective filter (16) occurs essentially in one mode.

Abstract: The instant invention provides a method and apparatus for use in laser induced dynamic light scattering which attenuates the multiple scattering component in favor of the single scattering component. The preferred apparatus utilizes two light detectors that are spatially and/or angularly separated and which simultaneously record the speckle pattern from a single sample. The recorded patterns from the two detectors are then cross correlated in time to produce one point on a composite single/multiple scattering function curve. By collecting and analyzing cross correlation measurements that have been taken at a plurality of different spatial/angular positions, the signal representative of single scattering may be differentiated from the signal representative of multiple scattering, and a near optimum detector separation angle for use in taking future measurements may be determined.

Abstract: An optoelectronic sensor arrangement comprising a light transmitter for the transmission of sequential operational light pulses into a monitored region and with a light receiver unit for the reception of operational light pulses reflected from an object located in the monitored region, wherein the light receiver unit includes at least two photosensitive elements, with a circuit for the suppression of stray light being associated with each photo-sensitive element.

Abstract: A flow cell 2, a composite lens 15, and first to third detectors 16 to 18 are arranged in this sequence in the light pathway of light emitted from a laser light source 1. The composite lens 15 is configured by a convex lens 15a, and lens elements 15b and 15c. These lenses have different focal lengths. When the posture of the composite lens is correct, light impinging on the convex lens forms an image on the first detector. Therefore, the positioning of the composite lens is enabled. When particles in the flow cell are irradiated with laser light, forward scatter is produced. Forward small angle scatter having a small scattering angle impinges on the first lens element 15b to be collected thereby, and is then received by the second detector 17. Forward large angle scatter having a large scattering angle impinges on the second lens element 15c in the outermost periphery to be collected thereby, and is then received by the third detector 18 which is remotest from the composite lens.

Abstract: A method for measuring an internal property distribution which includes making measurement light incident from a plurality of light incidence positions on a surface of a measured object, detecting the measurement light that has passed through the object, successively or simultaneously, at at least one light detection position out of a plurality of light detection positions on the surface of the object. A plurality of measurement values obtained by a plurality of combinations of the light incidence position and said light detection position are extracted. A mean value of the measured values are calculated to obtain a reference value and a change amount of a predetermined internal property in each of the plurality of regions of the object are calculated using the plurality of measured values obtained. The reference value thereby establishing an internal property change amount distribution in the object.

Abstract: An optical analyzer with a configuration particularly suitable for use with planar liquid sample flow cells is provided comprising a polarized light source and at least two large angle scattered light photodetectors positioned respectively at acute, and right or oblique angles to the incident light beams. Differences in intensities of light measured at the two photodetectors are used to quantify components of the sample.

Abstract: A light scattering particle size distribution measuring apparatus inches a light source for providing a beam of light to contact with a sample cell holding a specimen. A detector assembly includes a first set of detector assembly includes a first set of detector elements for receiving scattered and/or diffracted light from the sample cell and a second set of detector elements positioned between the first set of detector elements. A removable scattering and/or diffracting target member can be positioned on the optical axis to provide a predetermined scattered and/or diffraction pattern to the detector assembly whereby the second set of detector elements can measure the predetermined fraction pattern to enable a movement of one of the light source and the detector assembly to align them on an optical axis.

Abstract: In a particle detector, a stream carrying particles to be measured is passed through a laser beam. A pair of optical collection systems are arranged perpendicular to the laser beam, opposing each other. The optical collection system reflects light signals indicative of particles sensed in the sensing region to a pair of detector arrays. Each detector array has a plurality of detectors to detect the particle signals, as well as other noise. One detector from each array monitors the same sensing region. The signals from the detectors are processed through a noise cancellation circuit. The noise cancellation circuit first amplifies each detector signal through a photo-amp. Then, the signals of the detectors in one detector array are paired up with corresponding signals of detectors, spaced at least two detectors away, in the other detector array. The paired-up signals pass through differential amplifiers, which essentially cancel the light fluctuation noise.

Abstract: A method for monitoring the presence of particles in a plasma etch chamber. It includes the steps of: (a) selecting at least one laser light source whose wavelength is at such an energy which will cause the particles to be monitored inside the plasma etch chamber to emit Raman, Stoke, and anti-Stoke spectra lines when the laser light is scattered by the particle; (b) emitting the laser light into an internal space of the plasma etch chamber; and (c) using a set of fiber optics to intercept light that may be scattered by the particle, if the particle is present in the plasma etch chamber; and (d) measuring amplitude and spectra of the scattered light. Because the intensity of the scattered light is proportional to the dielectric constant to the fourth power, the method is most advantageous for detect the presence of metal-containing particles, which have a very high dielectric constant. The spectral analysis also provides information relating to the chemical composition of the particles.

Abstract: Apparatus and method for measuring the concentration of airborne fibers are provided. The apparatus includes a flow channel for providing laminar flow to a portion of the fibers in an air sample and a light source for generating a light beam directed to the laminarly flowing fibers to produce a scattered light. The apparatus further includes a sensor for sensing a portion of this scattered light and for producing an output from which a fiber concentration estimate can be measured.

Abstract: In a method for monitoring particulates in stacks or ducts a back-scatter monitor uses a solid-state laser to emit a collimated beam, the intensity of which is controlled via feedback from a reference detector. The beam is split so that part goes to a reference surface for calibration checks, and part is directed to pass at a selected angle through a gaseous sample. Optical energy scattered from particles in the sample is detected by viewing optics to provide an indication of particulate concentration. The beam steering mechanism can direct the optics to view scattering along a selectable axis that intersects the laser beam at a specified location within the gaseous sample. The method can be used to determine the opacity of the gaseous sample providing a basis for correlation to particulate loading of that portion of the particulates that are of a size comparable to the wavelength of light.

Abstract: A laser is irradiated on the surface of a semiconductor wafer while a stage mounted on the semiconductor wafer is moved, and scattering lights emitted from the surface of the semiconductor wafer is received by the receiving device, and an intensity distribution of the scattering lights is measured. The intensity distribution is processed by the controller so as to obtain a defect density of the semiconductor wafer.

Abstract: A method and apparatus for analyzing a fluid containing light scattering components. The apparatus includes a laser adapted to direct abeam of light into the fluid such as a liquid containing particles, and at least two detectors to receive light scattered by the fluid, which received light is used to calculate a physical property of the fluid. A focusing lens may be used to focus the light beam to a focal waist in the fluid to enhance the degree of spatial coherence of the scattered light. The two detectors are aligned onto the focal waist and are adapted to send a signal to a data processor which correlates the signal received from said two detectors. The two detectors are spaced a substantially equal distance from the focal waist and are oriented at substantially the same angle with respect to the direction of propagation of the incident beam. The data processor is adapted to cross-correlate the signals received from the two detectors.

Abstract: A method and apparatus for determining the size distribution of at least two different types of fluorescent or fluorescently stained particles in a sample by radiating light into a stream of singled particles and recording and analyzing both the scattered light and the fluorescent light. A relative particle size distribution for each individual particle type (T.sub.k) is calculated and then the relative particle size distribution for the individual particle types is normalized forming a joint relative particle size distribution of the at least two particle types with respect to one another.

Abstract: A contamination sensor is provided for use in a fluid system and machinery to continuously monitor the level of contaminants in a fluid. The contamination sensor includes a source of light that is directed into the fluid stream with three photodetector arrangements detecting light scattered by contaminants contained in the fluid. The first photodetector arrangement is located near the origin of the source of light. The second photodetector arrangement is located farther away from the source of light. The third photodetector arrangement is located perpendicular to the axis of the light beam and spaced from the source of light along the axis of the light beam. The simultaneous detected scattered light from a contaminant in the fluid is converted to electrical signals by the photodetectors, conditioned by a signal conditioning circuit and transferred to a signal processing unit for interpretation.

Abstract: An improved photo detector assembly for a particle size distribution measuring equipment provides a unitary opaque coating deposited above a photo detector layer with a plurality of concentric apertures that can be defined with high precision about a concentric center. The masking can be applied in a production environment to ensure high accuracy and a compact size.

Abstract: A wiper control apparatus of the water drop sensitive type for detecting of the amount of water or water drops adhering to or present upon the front surface of a windshield and for driving a wiper, comprising: a light emitting means for introducing light into the inside of the windshield so that the light experiences total internal reflection upon interior surfaces of the windshield; a light receiving means for receiving the light reflected within the windshield; means for turning a first output D1, a second output D2, and a third output D3 to either an H level or an L level in response to the level of a signal output from the light receiving means, the outputs being preset in sequence of height of sensitivity thereof; means for outputting a drive signal WD for the wiper when outputs D1, D2, and D3 are switched into the H level; means for maintaining the drive signal as long as the second output signal D2 is in the H level even if the third output D3 turns to the L level; and means for stopping the drive sign

Abstract: Light receiving elements detect the intensity of light scattered from a sample cuvette containing particles irradiated by a laser beam from a laser source. Signals from the light receiving elements are evaluated to determine the size and number of the particles for its time-series display. In measuring blood corpuscles, the clumps of aggregation can be determined in terms of size and number on a time-series base with high accuracy, thus providing a useful means mechanism for clinically diagnosing various diseases including thrombosis and for determining the effectiveness of remedies.

Abstract: A light scatter detector assembly for an analytical instrument, such as a laser flow cytometer or clinical hematology instrument having at least two angles of scatter. A high numerical aperture lens system is used, preferably a system using only two lenses to collect light after interacting with suspended particles passing through a flow cell into a collimated beam. A dark stop having apertures in different locations is interposed in the collimated beam light detected to produce therefrom two optical beams, respectively corresponding to the two scatter signals, e.g., high angle scatter and low angle scatter. The apertures are preferably radial sectors. The two scatter beams are passed to a beam separating element and through a collimating lens onto respective photodetectors. The beam separating element may be a split mirror having two mirrors mounted at an angle to each other, e.g., less than 15.degree., preferably 51/2.degree., to direct the beams in different directions to the two photodetectors.

Abstract: A particle monitor includes a light source for transmitting a light into a space over a wafer in wafer processing equipment to irradiate particles floating above the wafer for causing a scattered light; a photo-detector for detecting the scattered light to generate output signals corresponding to the intensity of the scattered light; a signal intensity judgment device for receiving the output signals from the photo-detector and comparing the output signals with a predetermined reference value already set in the signal intensity judgment device so as to judge whether the intensity of the scattered light is higher or lower than the predetermined reference value; and a display for displaying the intensity of the scattered light and luminance and distribution in intensity thereof or displaying distributions in size and the number of particles.

Abstract: The invention provides phospholipid coated particles capable of specifically binding antiphospholipid antibodies and a method for preparing such particles. Methods are also provided for determining antiphospholipid antibodies in a serum or plasma. Also provided are methods for isolating antiphospholipid antibodies from a fluid and for raising specific antiphospholipid antibodies.

Abstract: An optical sensor for counting and sizing particles, including a light extinction (LE) signal representative of the particles, and a light scattering (LS) signal representative of the particles. The light scattering signal and the light extinction signal are combined to form a single composite signal. The single composite signal has a substantially similar output to the light extinction (LE) signal for particle sizes in an upper range of particle sizes typically measured by the light extinction sensor. The single composite signal has a substantially similar output to the light scattering (LS) signal for particle sizes in a lower range of particle sizes typically measured by the light scattering sensor. The single composite signal has an output representing the combined light extinction (LE) signal and light scattering (LS) signal for particle sizes in a middle range of particle sizes.

Abstract: An improved method of monitoring particulates in stacks or ducts utilizes transmissometer/particulate monitor of the type which has an optical assembly containing a solid state light source of visible light such as a light-emitting diode or a solid-state laser. The light source emits a collimated beam that is split, part of which is focused onto a reference detector that monitors the intensity of the light source, while the other part is directed to a beam-steering apparatus that causes the beam to accurately pass through a gaseous sample to a desired location such as a retro-reflector. A position-sensing detector is used in a closed-loop manner to control the beam-steering apparatus. The ratio of the total energy of the detected light beam, relative to the reference detector output, is used to determine the opacity of the gaseous sample for the purpose of providing a basis for correlation to particulate loading of that portion of the particulates that are of a size comparable to the wavelength of light.

Abstract: A particle analyzer which can maintain optical characteristics of an optical system which is one component thereof at a fixed level for a long period of time is provided. In the particle analyzer comprising a flow cell for forming a sheathed sample flow containing particulate components; an irradiating optical system for irradiating a sheathed sample flow formed in the flow cell; and a light receiving optical system for receiving light emitted from the sheathed sample flow in the flow cell irradiated by the irradiating optical system, the light receiving optical system comprises a rod lens to which the light emitted from the sheathed sample flow in the flow cell enters and an entrance surface of the rod lens is curved.

Abstract: An in-situ imaging system suitable for analyzing particles or droplets contained in process reactor vessels or pipelines at full process concentrations is disclosed. The system includes a light source capable of high peak power output operated in a pulsed mode that is located inside of a probe. The light from the light source is coupled into an optical fiber. The light is carried by the optical fiber to a lens system near the end of the probe which focuses the light through a window to the area which coincides with the field of view in the focal plane of the imaging optics. The imaging optics collect the light which is back-scattered from particles or droplets, magnifying the image and projecting it onto an image detector such as a CCD array.

Abstract: Noise reduction is effected by multiplying together electrical signals that include pulses embedded in noise, with the pulses being indicative of the same event, such as light scattered by particles, occurring at a viewing area, and with the signals being processed prior to multiplication so that the pulses and the variance of the noise in the electrical signals are multiplied by one another. A detector in each of a plurality of channels detects the events occurring at the common viewing area and provides pulses indicative thereof, and the output from each detector is amplified, passed through matched low-pass filters to enhance pulse detection, and then passed through a baseline restorer to remove DC components from the noise then present in the signal, prior to coupling of the signals to a multiplier.

Abstract: The present invention provides an apparatus and method to determine individual red blood cell shape within a flow cytometric aperture. Cell shape is determined by measuring the asymmetry of a light scatter pattern produced by laser illumination of the cell within the aperture by light scatter detectors which collect light from specific angular regions of light scatter, and analyzing the asymmetry of the light scatter patters to determine the individual red blood cell shape. Embodiments of the invention further provide for the determination of red blood cell shape by measuring the asymmetry of a light scatter pattern and measuring electrical resistance of the red blood cell.

Abstract: A suspended particle concentration monitor includes near and far detector circuits with near and far elements sensing scattered visible or near infrared radiation projected into a fluid volume in which particle concentration is determined. The spacing and characteristics of the light sensitive elements and the gains of the near and far detector circuits are selected to produce generally equal peak signals at separate particle concentrations. A computer contains three tables each containing particle concentrations in respective portions of the particle concentration range being monitored. Based upon analysis of the near and far detector signals, one of the tables is selected and used to find the particle concentration corresponding to one of the near and far detector signals.

Abstract: A system for determining characteristics of objects in wood pulp includes a pulp sampling and dilution system for diluting and dispersing samples of pulp, and an imaging/analysis system for capturing images of pulp objects, including fibers, and analyzing the captured images. Samples of pulp are provided to a dispersion tank where pulp is dispersed within a liquid to form a wood pulp slurry having a consistency in the range of from about 0.01 to about 0.001 percent. The dispersed pulp is conducted to a transparent flow cell for imaging and analysis of pulp objects. Light radiating from a light source is reflected off surfaces of objects within the dispersed pulp, producing scattered light. One or more cameras capture scattered light from objects as the objects pass through a camera's field of view. The output of the cameras are digitized and filtered to eliminate motion blur, and the filtered visual image displayed on a monitor.

Abstract: A device for counting and measuring the particles provides a precise analysis of the particle characteristics and includes an ellipsoidal mirror system, having two different sizes ellipsoidal concentric mirrors (4) and (5) connected towards to each other by their cross-section lateral areas, and a first ellipsoidal mirror (4) is smaller than a second ellipsoidal mirror (5), includes also a light beam and a particulates flow passing inside the first ellipsoidal mirror (4) through a first focus of the first ellipsoidal mirror (4), concurred with a second focus of the second ellipsoidal mirror (5), also includes a light detector (20), which is placed inside the second ellipsoidal mirror (5) at a first focus of the second ellipsoidal mirror (5), concurred with a second focus of the first ellipsoidal mirror (4). An improved device comprises also an electronic control system, including an analog-digital subsystem (45) and a microprocessor subsystem (32), which provide the signal processing and control functions.

Abstract: A method and apparatus determines the shape characteristics of articles flowing through a transparent cell through which a light beam is projected. The intensity of light scattered by the particles is measured with a detector which has one or more concentric rings or parts of rings, at least one of which is provided with one or more isolated segments. The rings and the isolated segments are coupled to an energy meter, signal amplitudes therefrom are statistically processed to provide amplitude classes. The shape characteristics of the particles are determined from a graphical or numerical comparison of the amplitude classes.

Abstract: A specimen measurement apparatus and method includes sequentially moving individual specimens, radiating first and second radiation beams on first and second positions spaced apart from each other in a moving direction of the specimens, time-serially detecting light components emerging from specimens passing the first and second positions using the same light detector, and an optical selector, arranged in an optical path between the radiation positions and a light detector, for, when a specimen passes the first position, selectively guiding a light component having a first optical characteristic emerging from the specimen to the light detector, and for, when the specimen passes the second position, selectively guiding a light component having a second optical characteristic emerging from the specimen to the light detector.

Abstract: A radiant energy point source (10) generates radiant energy, and a mechanism (12, 15, 16) focuses the radiant energy generated by the point source onto a target (18) and scans the target with the focused radiant energy. A collector (16, 14) collects the focused radiant energy that is scattered from the target and a splitter (22) splits the collected radiant energy into two paths. Each of the two paths of the collected radiant energy is focused onto separate focal spots by a focusing mechanism (24). A pair of spatial filters (26, 28) filter the collected radiant energy at the focal spots. The spatial filters are offset from each other along the path of the focused radiant energy. Detectors (30, 32) separately detect the focused radiant energy which passes through each of the spatial filters and produce signals proportional to the quantity of detected focused radiant energy present.

Abstract: An improved transmissometer/particulate monitor of the type which has an optical assembly containing a solid state light source preferably a solid-state laser. The light source emits a collimated beam that is split, part of which is focused onto a reference detector that monitors the intensity of the light source, while the other part is directed to a beam-steering apparatus that causes the beam to accurately pass through a gaseous sample to a desired location such as a retro-reflector. A position-sensing detector is used in a closed-loop manner to control the beam-steering apparatus. The ratio of the total energy of the detected light beam, relative to the reference detector output, is used to determine the opacity of the gaseous sample or to provide a basis for correlation to particulate loading of the sample or both.

Abstract: A method for foreign particles inspection includes illuminating an inspection surface of an inspection object with a beam which is, one of s-polarized and p-polarized relative to the inspection surface of the inspection object. The illumination utilizes an optical axis which is generally parallel to the inspection surface or which intersects the inspection surface at an angle that is greater than or equal to 1.degree. and less than 5.degree.. Reflected and scattered light is detected utilizing an optical axis which makes an acute angle with the inspection surface and which makes a differential angle of 30.degree. or less with the optical axis of the illumination beam. The detection of foreign particles is accomplished by detecting the component of the reflected and scattered light which is the other of s-polarized and p-polarized relative to the inspection surface.

Abstract: A light receiving optical system and a particle analyzer including the same which can be miniaturized and simplified are provided. The light receiving optical system includes a light receiving lens provided integrally with a light selector for selecting and outputting light by attenuating part of the light incident on the light receiving lens.

Abstract: A liquid flow cytometer for counting and classification of particles such as biological cells and other microscopic particles in liquids that involves an optical system for irradiation and detection in a metering zone (7), thus enabling optical dispersion and fluorescence caused by the particles to be simultaneously detected when the particles pass the metering zone, includes in a first beam path (S.sub.1) a mirror reflector (9) with its focal point in the metering zone (7), a quarter-wave plate (8) between the metering zone (7) and the mirror reflector (9), a lens (6) with its focal point in the metering zone (7) and located on the opposite side of it together with a dichroic mirror (5) behind the lens and provided in such a manner that it gives reflection to a second beam path (S.sub.2). In the second beam path (S.sub.2) a beam splitter (4) is provided between the dichroic mirror (9) and a known per se light source (1), and produces a third beam path (S.sub.3).

Abstract: A cytoanalyzer includes a flow cell for aligning cells and permitting the same to pass therethrough, a semiconductor light emitting device for emitting a laser beam to the cells passing through the flow cell, and a light-detecting device having at least two separate photosensing portions capable of sensing two types of light scattered by each of the cells. The alignment of the cytoanalyzer may be achieved by comparing intensities of light on the at least two separate photosensing portions.

Abstract: An optical illuminator assembly for an analytical instrument, such as a clinical hematology or a flow cytometer instrument, including a laser diode having a diverging laser beam output, a collimating lens to collimate the diverging laser beam, a spatial filter operating on the collimated laser beam to spatially filter the beam, and a focussing lens to focus the spatially filtered beam into a flow cell containing particles suspended in a moving stream. A beam shaping aperture is preferably inserted between the spatial filter and the focussing lens to shape the laser beam. The spatial filter preferably includes an objective lens, a collimating lens, and a filter aperture interposed between the objective and imaging lenses. The filter aperture is preferably rectangular, having a height to width ratio in the range of 1:2 to 1:3 such that each dimension is on the order of tens of micrometers.

Abstract: A surface inspection system and methods of inspecting a surface of a workpiece are provided for detecting particles, defects, or other surface characteristics in or on a surface of the workpiece. The surface inspection system preferably has a transporter arranged for transporting a workpiece along a material path and a rotator associated with the transporter and arranged for rotating a workpiece during translational travel along the material path. A scanner is positioned and arranged for scanning a surface of a workpiece during rotational and translational travel along the material path. The scanner preferably includes a light source arranged to generate a light beam therefrom and a deflector positioned to receive the light beam and arranged for deflecting the light beam along a predetermined scan path across a surface of the workpiece as the workpiece rotationally and translationally travels along the material path.

Abstract: A apparatus for sensing flow and/or other characteristics of a fluid, including an emitter adapted to project a light beam, a detector adapted to transmit a signal in response to receiving the light beam and a rotatable member for transmitting the beam of light from the emitter to the detector through a quantity of the fluid. Optic fibers/light pipes may be used to transmit light to the emitter from a light source, through the rotatable member and to a processor remote from the detector. The rotatable member may also include reflective and nonreflective zones for transmitting light passing through the fluid to the detector. A plurality of light pipes, blades, emitters and detectors may be used on the rotating member depending on a particular application of the present invention.

Abstract: A structure and a method provide a quasi bright field particle sensor for the detection of non-spherical particles, using a laser beam of predetermined polarization. A phase shift caused by non-spherical particles passing through the laser beam is utilized to detect the presence of such particles. In one embodiment, a single laser beam is used to detect the concentration of non-spherical particles in the pump line receiving the exhaust gas from a process chamber.

Abstract: A fiber optic spatial filter assembly for laser diffraction particle sizing apparatus utilizing a laser to generate a monochromatic light beam which is coupled to an optical fiber operating substantially in a monomode and creating a beam of light having a high degree of spatial coherence which is then passed through collimating lenses to interrogate and impinge upon the particles of matter through which the laser diffracted light passes. The light scattered by the particles is focused onto a Fourier plane and thereafter impinges upon a photooptical detector array, positioned coincident with the Fourier plane, for measuring the light intensities of the scattered light by scattering angle, thus enabling the computation of particle size.

Abstract: The chemical properties of an aqueous liquid, the liquid comprising a solvent having an index of refraction which is the same as or closely approaches that of water, are determined by Raman spectroscopy wherein a sample of the liquid is delivered into an optical waveguide. The waveguide is in the form of a capillary having a reflective surface defined by a material having a refractive index of less than 1.33. Excitation light is transmitted axially into the liquid at an end of the waveguide. The excitation light is transmitted the length of the waveguide, by reflection from the reflective surface, causing the fluid to emit Raman spectra. The Raman spectra is transmitted along the waveguide, collected and delivered to a spectrometer.

Abstract: A nephelometer instrument capable of measuring from zero to 10,000 NTUs. The instrument includes four light detectors, three of which are positioned such that they measure light scattered at specific directions by a liquid sample. The fourth detector measures light transmitted through the sample. A removable light filter is also included. The light beam is focused on the front surface of the sample cell.

Abstract: An apparatus and method are disclosed for obtaining and analyzing light scattering data to determine the size distribution of a group of dispersed particles that scattered the light. The apparatus and method use a two-dimensional array of photosensitive pixels such as a charge-coupled device (CCD) or an array of solid-state photodiodes. The analyzer illuminates the particles with a dose of light in a collimated beam from a light source so as to scatter light of the beam, and at least a portion of the light interacting with the particles is detected with the photosensitive pixel array. The pixels are functionally equivalent and the analyzer dynamically configures and re-configures at least a portion of the pixels into a variable number of data collection areas which correspond to a selected set of scattering angles. The analyzer also determines whether and, from the pixel output data, where an unscattered center of the incident light beam intersects the pixel array.

Abstract: An apparatus measures the diameter, relative concentration and weight of particles. The detection of scattered light produced when light is projected at particles drawn into a nozzle-shaped measuring space is used to measure particle diameter, particle concentration is measured based-on variations in the intensity of transmitted light, and particle weight is measured based on changes in operating frequency of a crystal oscillator resulting from the adhesion of particles on the surface of the crystal oscillator.

Abstract: A method of detecting impurities in a molten resin. The molten resin is massed through a passage having a window through which light can pass. Light is emitted from a light source through the window and the molten resin flowing through the passage. Sensors are used to sense a shadow produced when the light from the light source is interrupted by an impurity contained in the molten resin. Finally, the size of the impurity is measured from the width of the shadow and the intensity of light of the shadow. Also, judgment is made that if optical signals obtained by detecting the light that has passed through the molten resin indicate that there exist bright areas around a dark area, the dark area is distinguished as a shadow of an impurity. Further, in order to judge the shape of an impurity with high accuracy and record its image, a plurality of the devices used in the above method or the device used in the above method and a conventional camera may be used in combination.

Abstract: A method and apparatus are described for flow cytometric absolute sizing of individual biological particles and for determining and reporting fluorescence data which is surface area or volume normalized.