Abstract: An improved method of collecting quasi-elastic light scattering (also known as QELS) data and time-average intensity simultaneously is disclosed, as is a novel apparatus therefor. The apparatus utilizes a novel optical element having a pair of diametrically aligned slits on a masking disc that eliminates the need of index matching fluids that are currently required to eliminate flare from the sample cell walls at the cell-sample and the cell-air interfaces. The novel optical element allows improved angular resolution and on-axis resolution for the fluctuation data obtained.

Abstract: A fire alarm system which radiates light towards a smoke detecting space. Scattered light resulting from smoke that may exist in the smoke detecting space is judged by a receiver with respect to the type of smoke that may prevail in the space. The presence of a fire is judged by comparing the light that has been received with a set threshold level. The threshold level is set to different levels in accordance with the type of smoke detected.

Abstract: The invention relates to a method and an apparatus for determining the size or the size distribution of fine particles. A single particle or a group of particles are shone by a parallel polarized beam of a single wave length and the scattered intensity on the plane of polarization of the incident beam is measured by a photodetecting array. For a single particle the size is determined from the peak scattering angle at which the profile of the product of the scattered intensity and the scattering angle has the peak. On the other hand, for a group of particles, the size distribution is determined from the angular variation of the scattered intensity or the profile of the product of the scattered intensity and the scattering angle measured on the plane of polarization of the incident beam.

Abstract: A sample cell for use in measuring the particle size distribution of samples using diffraction-scattering measurement methods has a radiating surface which is beveled to increase the angle of incidence of scattered light which is scattered at a large scattering angle such that it is transmitted through the radiating surface of the sample cell and thereby allowed to impinge upon a detector.

Abstract: An apparatus and method for measuring the volume and hemoglobin concentration of individual red blood cells in a whole blood sample provides for isovolumetrically sphering the red blood cells of the sample using a sphering reagent and forming a stream of individual, spaced-apart cells sheathed in an electrolytic liquid in a flow chamber. The red blood cells in the stream are passed through a light scattering channel in which the intensity of light scattered by each cell into a preselected angular interval in the forward direction is measured. Each cell in the stream is also passed through a resistance pulse sizing aperture for measuring the volume of the cell.

Abstract: The illumination system as a part of an optical inspection system, the total inspection system itself, and the method of illuminating and inspecting a workpiece. The illumination system is computer controlled as to a level of intensity and adjustable as to angle of incidence. The illumination system includes illumination control electronics, a quad quartz halogen lamp array light source, a fiber optic line converter and an illumination collection system, having a collimator lens array and a focusing/field coverage lens. As a result of the present invention, determinations of false defects on the PCB are minimized. Human contact with the PCB is also minimized and the rate of inspections performable is increased.

Abstract: A non-imaging particle counter 10 utilizing one or more detectors 25 which directly collect light scattered by particles in a fluid traversing a sensing volume 63. The detectors 25, are non-imaging, non-focusing, optic-less light collection devices, such as large area photodiodes. The detectors 25 are arranged and configured proximate the sensing volume 63, but such that the beam of light 60 is not operatively incident thereon. The beam of light 60 is provided by a laser 50 and is shaped by a focusing/collimating lens 54. The beam of light 60 passes through several apertures 51-53 to reduce stray/background light in the system. The detectors 25 are oriented at an angle with respect to the plane formed by the longitudinal axis of the beam and the flow of fluid, wherein stray light 61 strikes the detectors 25 at an angle greater than the acceptance angle of the detectors 25, while scattered light strikes the detectors 25 at an angle less than the detectors' 25 acceptance angle.

Abstract: Laser-warning method and a laser-warning arrangement, which laser-warning arrangement is intended to warn of laser light from a laser beam source which is used for guiding projectiles, missiles and the like, for example laser light from a pulsed laser beam which is directed towards a target area. The time for the laser beam to reach the laser-warning arrangement, the so-called impact time, is calculated from a first amplitude value, measured at a first point in time, of the scattered light from the laser beam and a second amplitude value, measured at a second point in time, of the scattered light from the laser beam, and the measured time difference between the said first and second points in time on the basis that the amplitude raised to a constant is proportional to the distance to the laser beam according to the equation D=K.multidot.A.sup.n, where K and n are constants, D is the perpendicular distance to the laser beam and A is a measured amplitude value.

Abstract: An improved method of collecting quasi-elastic light scattering (also known as QELS) data and time-average intensity simultaneously is disclosed, as is a novel apparatus therefor. The apparatus utilizes a pair of matched novel optical elements that eliminate the need of index matching fluids that are currently required to eliminate flare from the sample cell walls at the cell-sample and the cell-air interfaces. The novel optical element incorporates desirable aspects of a pinhole aperture optical system and a double lens and center mask optical system.

Abstract: An arciform photosensor assembly for use in an optical apparatus for detecting the radial intensity distribution of light scattered, for instance, from particles suspended in a fluid medium. The assembly includes three groups of arciform photosensor to be used for adjusting the optical axis of the optical apparatus in which this arciform photosensor assembly is used as a light detector.

Abstract: A method and apparatus for separating particles by means of a contra-flow centrifuge, wherein a monitor system is used to analyze or control the separation process. The monitor system used impinges a monochromatic light beam on a sample of the separated particles, and measures the light scattering not only in the beam-forward direction, but also in the beam-reverse and beam-lateral directions. This reduces the processing time and increases the reliabiity of output data.

Abstract: Apparatus measures the scattered radiation received by a detector device in a measuring station (F) situated on the side of the beam path (O). The detector device has a sensitivity lobe which has a given limited lobe width (2.DELTA..theta.) and which lobe can assume different angles (.alpha.) relative to a reference line (R). In the measuring station (F) the time distance between the front flank and the rear flank of the scattered radiation reaching the detector device, i.e. the pulse width or the pulse length of the scattered radiation, is determined in at least two different angular positions (.alpha.) of the sensitivity lobe. The position of the light beam path is then determined by means of the measured pulse widths in combination with the associated known angular positions of the sensitivity lobe.

Abstract: A propellant sample combustion apparatus employing a multiply optical ported pressure vessel for sample illumination, sample viewing, and sample burn face elevation is described. High-speed motion picture filming using short-duration high-intensity laser provided optical illumination from a copper-vapor laser is employed. Details of the employed pressure vessel, a burn inhibiting coating for the propellant sample, a laser coherence spoiler, and a sample level maintaining closed-loop apparatus are also disclosed.

Abstract: An apparatus and method which provides a measure of the size distribution of particles dispersed in a fluid based upon an optimum combination of CLS measurements and DLS measurements. The measurement is characterized by relatively high resolution particle sizing. DLS data representative of the autocorrelation function, or power spectrum, of the detected intensity of scattered light for m measurement conditions of a sample, is optimally combined with CLS data representative of the average total detected intensity of scattered light for n measurement conditions, to provide an angle-independent, high resolution size distribution v(r), where m.gtoreq.1, n.gtoreq.0, m+n.gtoreq.2, and at least two of the measurement conditions are different. The size distribution may be expressed in terms of the continuous function v(r) or the histogram v, and may represent distributions weighted by mass, volume, number, surface area, or other measures.

Abstract: A photometric method and apparatus for measuring agglutination in a biological agglutination reaction system test sample using a laser beam source and at least one photodetector for detecting light scattered by the test sample. The method includes the following steps: (1) arranging the at least one photodetector so as to be capable of detecting scattered light from the test sample at a scatter angle of 30 to 60 with respect to a laser beam directed at the test sample from the laser beam source; (2) irradiating the test sample with the laser beam from the laser beam source; (3) selectively detecting the intensity of scattered light from the test sample at the scatter angle of 30 to 60 using the at least one photodetector which provides an output indicative thereof; and (4) determining the first derivative of the output of the at least one photodetector with respect to time and obtaining the maximum value thereof.

Abstract: Interferometric apparatus and method for detection and characterization of particles using light scattered therefrom. Differential phase measurements on scattered light from particles are possible using the two-frequency Zeeman effect laser which emits two frequencies of radiation 250 kHz apart. Excellent discrimination and reproducibility for various pure pollen and bacterial samples in suspension have been observed with a single polarization element. Additionally, a 250 kHz beat frequency was recorded from an individual particle traversing the focused output from the laser in a flow cytometer.

Abstract: An apparatus and method which provides a measure of the size distribution of particles dispersed in a fluid based upon an optimum combination of CLS measurements and DLS measurements. The measurement is characterized by relatively high resolution particle sizing. DLS data representative of the autocorrelation function, or power spectrum, of the detected intensity of scattered light at a plurality of angles about a sample, is optimally combined with CLS data representative of the average total detected intensity at those angles, to provide an angle-independent, high resolution size distribution v(r). The size distribution may be expressed in terms of the continuous function v(r) or the histogram v, and may represent distributions weighted by mass, volume, number, surface area, or other measures.

Abstract: Methods useful for differentiating and enumerating subpopulations of particles in a sample and more particularly relates to the enumeration of leukocyte subclasses. Enumeration is accomplished by utilizing two light scatter parameters and converting these parameters to a single parameter by employing a mathematical, nonlinear transformation.

Abstract: In an apparatus in which particles which may include biological cells are passed through an optical sensing zone to measure their spatial radiant energy distribution for the purpose of identifying and/or characterizing the particles or cells, a structure and method are provided for increasing the usefulness of a geometric configuration of photovoltaic detectors such as a known assembly of generally concentric rings of such detectors usually including some wedge-shaped detectors. These are provided in a generally planar form and the invention provides structure which captures radiant energy in a flow cell of a particular type before projecting the energy to the detector. In particular an ellipsoid, paraboloid, hyperboloid or similar reflector which is symmetrical about its optical axis is utilized first to capture the radiant energy on angles which could include most forward and/or backward angles and all azimuthal angles and then deviating the same to the detector assembly mentioned.

Abstract: A method of determining the size of spherical particles, comprising the operations of illuminating with a beam of circularly polarized light particles the size of which is to be determined, detecting light backscattered by the particles, measuring the angular intensity distribution of the backscattered light and deriving therefrom an indication of the size of the particles.Various forms of apparatus for carrying out the method also are described.

Abstract: A method for deriving a quantitative measure of a beverage which will correlate to the subjective sensory stimuli response of beverage consumers. The method comprises illuminating an aliquot or a dilution thereof with a beam of monochromatic light, measuring the light scattering pattern produced, comparing this pattern to that of a reference pattern, and using the difference between the two patterns as the quantitative measure. A variation of the method is disclosed wherein a number of measurements at a selected set of angles over a period of time are measured and, at each selected angle, the intensity is measured several times. In this method, the average of the intensities so detected at each selected angle is determined, and the numerical set of the fluctuation of each detected value from the average is used to characterize the beverage.

Abstract: A method of the quantitative measurement of antigens and antibodies by reacting an antigen or antibody or a mixture thereof with the corresponding antibody and/or antigen which has been supported on insoluble carrier particles, irradiating the resulting reaction mixture with light of a specific wavelength to measure the intensity of light scattered by the reaction mixture.

Abstract: What is disclosed is an improved nephelometric method for detecting an antigen or antibody by contact thereof in a liquid medium with particles of a latex reagent comprising latex particles of different sizes loaded with different amounts of a corresponding antibody or antigen and then measuring the light scattered by a latex reagent.

Abstract: An in situ turbidity meter, for measuring water quality of a body of water comprising a pulsed infrared laser which illuminates the water, thereby producing scattered radiation from particles suspended in the water. A portion of the scattered radiation is collected and correlated to the turbidity of the water.

Abstract: A novel method and a novel apparatus therefor are described for detecting and measuring a predetermined immunochemical substance, for example, an antigen, an antibody, a hapten, or certain low molecular weight substance. The detection and measurement of an immunochemical substance using the method and apparatus of the invention involves providing for the agglutination of a suspension of particles in a sample, or color intensity of solutions by which, using the apparatus of the invention to determine certain electromagnetic radiation properties of the sample, the presence and amount of the immunochemical substance can be determined.

Abstract: The disclosure relates to a radial scanner usable for scanning a small volume of a test sample in a differential light scattering analyzer. In the scanner a beam of collimated light impinges on a rotating planar mirror located above or below the test sample on an axis passing through the small volume. A beam of light reflected from the mirror sweeps a conical mirror, having its reflecting surface curved about a reference axis passing through the small volume. The small volume is scanned by a beam of light reflected from the conical mirror at different radial angles as the planar mirror is rotated.

Abstract: A diagnostic technique to histologically detect malignancy and other tissue properties is performed by pressing a solid tissue sample between a pair of planar parallel plates transparent to ultraviolet light to a fraction of the original thickness of the sample and by subsequently passing focused ultraviolet light therethrough. The ultraviolet light is passed transversely to the planar glass plates and the emerging angularly distributed light is analyzed to determine a dignity parameter of the sample containing diagnostic information. The dignity parameter is a unique, monotonous and continuous function of the relation of the forward scatter coefficient to the extinction coefficient of the compact portions of the tissue of the sample.

Abstract: A particle size analyzer having an optical assembly with a light source and a lens producing by reflected light an image of a field of particles carried on a moving conveyor. The image is cast upon two photo-transducers which produce substantially identical signals relatively displaced in time by an amount inversely proportional to the rate of conveyor movement. These two transducer signals are fed to discriminator means to develop respective sets of pulse signals identifying predetermined transition characteristics in the light transmitted to the transducers. These two sets of pulse signals are used to develop a control signal for adjusting the frequency of a clock-pulse generator such that a given number of clock pulses represents a corresponding distance moved by the conveyor, irrespective of its speed. One of the sets of pulse signals is used to gate the generated clock pulses to a counter and accumulator system which provides output signals representing certain particle size parameters.

Abstract: A wireless smoke detector apparatus including at least one detector/transmitter unit and a receiver/annunciator unit. The detector/transmitter having a pulsed infrared radiation source, a photodetector having an optical axis angularly intersecting the axis of the radiation source for detecting radiation scattered by smoke particles and a transmitter responsive to the output of the detector for transmitting a unique receiver/annunciator actuating signal which is distinguishable by the receiver/annunciator from other actuating signals.