Abstract: A method for detecting a cause of an abnormal portion present on a surface of a steel product, which comprises the steps of: condensing a pulsed laser beam, irradiating the pulsed laser beam thus condensed onto an abnormal portion present on a surface of a steel product and a vicinity thereof, limiting pulse energy density of the pulsed laser beam at an irradiation point of the pulsed laser beam on the surface of the steel product within a range of from 10 kW/mm.sup.2 to 100 MW/mm.sup.

Abstract: An apparatus and method for optically measuring the air gap between a transparent glass disk and an air bearing slider without separately measuring the real index of refraction n and extinction coefficient k of the slider using an external ellipsometer. The phase offset required to compute the air gap is computed from a measurement of the air slider reflectivity and from an empirically derived equation that correlates the index of refraction with the reflectance of the slider. The apparatus includes a light source for directing a light beam through the transparent member and air gap, and onto the reflective slider. The light reflects off of the slider and the transparent member to create an interference pattern. The reflected light is detected by a photodetector that is coupled to a computer. The slider reflectivity r is found from the reflected light. An empirically derived linear equation which correlates the real part (n) of the slider refractive index to reflectivity (r) is next used to estimate n from r.

Abstract: The present invention relates to the field of quantitative microspectroscopy, and in particular to a method for determining the exact thickness of an optical microscopic sample.The thickness is determined by using optical marks whose position is determined through an in-focus position measurement of a first and second optical mark. After these two positions measurements are performed, the thickness of a sample is determined through a mathematical calculation using these two values.

Abstract: A smoke detector incorporates a porous plastic material which carries a hydrophilic agent alone or in combination with a surfactant which can be sprayed or deposited onto structural elements of the detector. The detector can include a molded removable plastic element that carries a hydrophilic agent. The element can be arranged to surround a light beam injected into a sensing region of a photoelectric detector.

Abstract: A gas analysis apparatus includes an optical source for providing an optical signal, an interferometer for modifying the optical signal, and an optical signal detector. A first housing having folded path optical elements positioned therein; the elements defining a sample path through which the optical signal passes from the interferometer to the optical signal detector. The first housing has a sample introduction opening. A second housing defines a sample holding volume. The second housing is sealingly positioned with respect to the first housing for fluidly connecting the sample path of the first housing with the sample holding volume of the second housing through the sample introduction opening. A recirculating flow may be provided between the sample path and the sample holding volume. The second housing may include an access port with a detachable access closure through which a material may be placed in the sample holding volume. A method for using the apparatus is also described.

Abstract: A Fourier transform spectrometer for use, among others, for sensing gases or liquids includes two polarizers, a birefringent optical component interposed between the two polarizers and a detector. Light from an extended source is substantially polarized by a first of the two polarizers, split into divergent beams by the birefringent optical component, and again caused to converge by the birefringent optical component so that, after passing through a second of the two polarizers, the light forms an interferogram in a plane behind the birefringent optical component where the detector is situated. The Fourier transform spectrometer is thereby provided with a way of forming an interferogram of the light from the extended source without a lens or a second birefringent optical component. This improves the field of view of the spectrometer and is likely to reduce its cost.

Abstract: A measurement of nonlinear refractive index coefficient of an optical fiber with a Sagnac interferometer, comprises the steps of employing the optical fiber in a Sagnac interferometer, splitting a signal beam into two signals, launching the two split signals into the interferometer in opposite directions, combining and detecting the signals counter-propagated in the interferometer, and detecting the refractive index coefficient of the optical fiber in accordance with the difference between the two signal powers determined by a control beam. The quasi-static phase shift of the signal beam counter-propagating the same paths of the interferometer is induced by rotating the optical fiber loop of the interferometer. The present invention gives rise to little error because it does not require precise information about the pulse width of a used beam or a high-power light.

Abstract: A method for calibration and correlation of flying height testers with a calibration slider. The calibration slider has an air bearing surface that contains a flat portion and a sloped portion. To verify accuracy and correlation between flying height testers, the calibration slider is loaded adjacent to a rotating transparent disk of a tester. The slider is separated from the disk by an air film and flies at a zero pitch angle. Zero pitch angle can be attained by adjusting the rotational speed of the disk. The flying height tester includes an optical system which can measure the air film with a light beam that is directed through the disk and reflected from the slider.

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 variable focus contact lens, has a body with a first half and an opposite second half. The body also has a first peripheral surface, an opposite second peripheral surface and an associated focal length. The lens includes a first material having a resilience so that as compressive force is applied to the first surface and the second surface, the focal length of the lens changes in proportion to the compressive force. A force-distributing structure is disposed within the lens for distributing force within the lens so as to inhibit astigmatism in the lens as compressive force is applied to the first surface and the second surface.

Abstract: A process for detecting inhomogeneities, specifically, striae in a sample of fused silica glass is provided which includes the steps of: preparing a digitized phase plot for the sample using an interferometer which produces a beam of light which passes through the sample; applying a high pass filter to the phase plot to remove the effects of the sample's bulk properties; applying a statistical filter to the high pass filtered data to remove outlying data points; and column averaging the statistically filtered data. If present, striae can be readily detected in the column averaged, statistically filtered data.

Abstract: The proposed image-processing method for determining the structural strength of a test object with a diffuse-scattering surface involves: the creation of an interferogram based on radiation back-scattered by the surface of the test object; conversion of the intrerferogram into a modulo-2.pi. image; and the stabilization of the modulo-2.pi. image to form an output grey scale value image. From the later, an identical duplicate grey scale value image is produced; this is then geometrically shifted and modified by applying an invariable grey scale value in the entire image area, before being finally subtracted from the initial grey scale value image to produce a grey scale image containing easily evaluated information on deformities in the observed test object.

Abstract: A catadioptric imaging system for an interferometer includes a beamsplitter plate for reflecting a beam of light to a concave mirror for transmitting reflected light from the mirror. The beamsplitter reflections and transmissions produce opposite sign spherical aberrations. A refractive optic is located between the beamsplitter plate and a convex test surface for removing residual spherical aberrations and for permitting more variability in the positioning of the beamsplitter plate. Design variables for both the refractive optic and the position of the beamsplitter plate can be used to adjust a numerical aperture of the beam approaching the test surface. The refractive optic can also be used as a Fizeau objective to further reduce errors in the imaging system.

Abstract: An analyzer for analyzing urine material components includes: a sheath flow cell for forming a sample stream containing the urine material components; a light source for illuminating the sample stream; a section for detecting optical information from the illuminated material component particles; and an analyzing section for analyzing the material components; the analyzing section including a parameter extracting section for extracting parameters from the detected optical information, a section for generating a distribution diagram for the material components on the basis of the extracted parameters, a section for inputting an expectative domain of a particular material component in the distribution diagram, and a warning section for giving a warning when a cluster of data points of the particular material component deviates from the expectative domain by more than a predetermined degree.

Abstract: The present invention is a method for calibrating power spectral data obtained with an interferometer based Fourier transform spectrometer which utilizes a laser based coherent radiant source as the metrology source. A radiant beam of predetermined wavelength from a neon lamp based noncoherent radiant source is directed in parallel with a radiant beam from the laser source into the interferometer to create a laser based interference pattern and a neon lamp based interference pattern. Distinct fringe counts are derived from the laser based interference pattern and the neon lamp based interference pattern. The wavelength of the laser source is determined based on a correlation between the known wavelength of the neon lamp based interference pattern and the determined fringe counts. The scale of the power spectral data is calibrated based on the determined wavelength of the laser source.

Abstract: In accordance with the disclosure there is described herein a simultaneous vision lens that incorporates both continuous aspheric and concentric bifocal optics into a single optical lens that may be configured as a contact lens or an intraocular lens.

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 character and/or graphics pattern area for recording specific data is provided on a CD-ROM. When an original disk is prepared, a specific pit pattern corresponding to the specific data is recorded at a first predetermined tracking linear velocity controlled by a specific tracking linear velocity control system for each track so that a character and/or graphics pattern cannot be identified. When a copy disk is produced from the original disk, if data is recorded at a second tracking linear velocity controlled by a specific tracking linear velocity control system, the character and/or graphics pattern of visible size appears on the copy disk because of an optical reflection factor difference between areas caused by placement of the specific pit pattern corresponding to the specific data.

Abstract: A non-contact optical backscatter insertion probe includes an outer chamber, an electromagnetic energy source positioned within the outer chamber for emitting photons towards a medium to be analyzed, and an inner chamber positioned within the outer chamber. The inner chamber has a reflective outer surface to prevent photons emitted by the electromagnetic energy source in the outer chamber from entering the inner chamber. The probe also includes a sensor positioned within the inner chamber for receiving backscattered photons from the medium. The inner chamber provides the backscattered photons emitted from the medium to the sensor. A processor receives and processes signals output by the sensor.

Abstract: The invention provides a method and a system for measuring geometric properties, such as diameter, shape and surface roughness of single rough particles by an optical method. The particle may be immersed in a gaseous or liquid fluid. A volume of the fluid, containing the particles to be measured, is illuminated by a beam of coherent electromagnetic radiation, resulting in a distribution of scattered radiation with a speckle structure. This distribution is detected with a one-dimensional or two-dimensional image detector. An autocorrelation function RI(r) of the detected intensity distribution is calculated, and from the position .delta.r of its first zero the diameter d.sub.P of the scattering particle is evaluated based on I, the wavelength of the electromagnetic radiation, and Z.sub.0, the distance from the particle to the detector.