Abstract: In order to reduce the size of a spectrophotometer having a rotatable diffraction grating and to compensate for longitudinal chromatic aberration and to provide for triangular bandwidth (where the image of the entrance aperture through which the light to be analyzed enters the spectrophotometer is equal in width to the width of exit slit through which the spectral components of each band are passed to a photodetector) thereby enabling high, accurate resolution of spectral line locations and edges of colors to be obtained, the diffraction grating is pivoted about an axis laterally displaced from the grating in the tangential plane, which plane contains substantially all of the light paths in the spectrophotometer. The exit aperture rotates with the grating and has a displacement from the grating in a direction transverse to the direction of displacement of the pivot, which displacement may be in the sagittal plane of the spectrophotometer.

Abstract: A method for determining the decay-time constant of a fluorescing phosphor is provided, together with an apparatus for performing the method. The apparatus includes a photodetector for detecting light emitted by a phosphor irradiated with an excitation pulse and for converting the detected light into an electrical signal. The apparatus further includes a differentiator for differentiating the electrical signal and a zero-crossing discrimination circuit that outputs a pulse signal having a pulse width corresponding to the time period between the start of the excitation pulse and the time when the differentiated electrical signal reaches zero. The width of the output pulse signal is proportional to the decay-time constant of the phosphor.

Abstract: This invention relates to an apparatus for mixing compositions of matter into a homogeneous mixture and detecting on-line the homogeneity and potency of the mixture, and a method for using the same. More particularly, this invention relates to an apparatus for mixing the components of a pharmaceutical composition into a homogeneous mixture and detecting on-line the homogeneity and potency of said pharmaceutical composition.

Abstract: Apparatus for and a method of detection of light transmitted or reflected from a test object using any one of plural filters each with a unique center wavelength. To prevent chromatic aberration in non-collimated light passed through the filters, the thickness of each filter is unique, depending on its center wavelength.

Abstract: An inspection system for inspecting products that have a flat, reflective surface, such as a wafer or a flat panel display on which a thin film is to be deposited, includes an inspection chamber connected to a processing chamber with both of the chambers being under vacuum. The inspection equipment performs the inspection with the product in the inspection chamber without removing the product from the vacuum environment. In a preferred form of the invention, the inspection chamber includes a wall portion that will transmit light, and the inspection equipment is a laser source directed to the reflective surface of the product and a receiver for receiving reflected light to determine changes in the character of the surface caused by the deposited film or by imperfections, haze or particles.

Abstract: A process for measuring the wheel profiles of wheels of wheelsets in which the wheelsets are moved past a series of a least twenty-six separate sensors while being rotated and moved at specified speeds. The wheelsets are impinged with a multiplicity of laser beams whose reflections are measured by the sensors, thereby indicating various wheel profile properties. In one embodiment, the wheelsets are rotated at a speed of less than 75 revolutions per minute while being moved at a speed of less than 6 miles per hour. In another embodiment, the wheelsets are rotated at a speed of greater than 400 revolutions per minute while being moved at a speed of greater than 45 miles per hour. In both embodiments, the wheelsets are moved past the sensors in a period of less than about 20 seconds.

Abstract: A first invention of the present application is an optical spectrum analyzer comprising a spectrometer apparatus an arithmetic unit for calculating the center wavelength from output signals from photo detector devices of a device array included in the spectrometer apparatus and from the light power distribution at an incident port by interpolation and for calculating the total power, and a display unit for displaying values of the center wavelength and total power. The dispersing device directs light introduced from the incident port at the dispersing device. Light going out of the dispersing device is focused onto the device array. In this structure, the outputs (theoretical values) from the photo detector devices are calculated. Where the n-th device of the device array producing a maximum output deviates from the center of the outgoing beam impinging on the device array by an amount of .DELTA.x, the relation between the deviation .DELTA.x and the associated photo detector device is found in advance.

Abstract: A fluorimeter has a flash lamp, a measurement station with a receiver for microtitration plates, at least one measurement head disposed at the receiver and an evaluation station having a detector. Emission signals given off by a sample are evaluated by the detector. Light guides extend from the flash lamp to the measurement head from the measurement head to the detector. At the measurement station one measurement head is arranged above a sample and one measurement head beneath the sample. A change-over switch is formed by a pivotal bar which connects the light guides selectively to the upper or the lower measurement heads. On the pivotal bar are connections for the light guides which lead to the upper and the lower measurement heads. Connection of a respective measurement head can be brought selectively into correlation with the light source and the detector.

Abstract: A color measuring device measures the light transmitted through the material to be measured as well as the light reflected therefrom and the irradiated light and measures the color reflectivity in the various spectral ranges by dividing the reflected intensity by the difference between the irradiated and transmitted intensity. The calculation of the color reflectivity in the individual spectral ranges is thus corrected to the proper extent without the need to place color tiles behind a transparent material to be measured.

Abstract: An optical method and system for measuring bore hole diameter, out-of-roundness and lobing and a probe for use therein are provided. A ring of structured light is initially formed or projected on the inner surface of a bore hole by optical components supported within a housing of the probe. A lens system also supported within the housing images the ring of light. Image merging lenses of the lens system reform the image at a video camera located at a window of the housing such that two or more arcs of the ring form a magnified image with the image of the arcs being shifted in space such that all the arcs can be viewed by the camera. The video camera image is captured by a frame grabber/computer. A computer calculates the location of the arcs and from this information determine bore diameter and other bore properties such as out-of-roundness and lobing.

Abstract: A photodetector is used to monitor contamination of optical elements within an optical system. The photodetector is aligned to detect nonspecular/diffuse reflections attributable to surface irregularities of particulate matter residing on the surfaces of the optical elements within the system. An increase in the intensity of the nonspecular reflections corresponds to increased levels of contamination on the surface of the optical element. An electronic detector circuit performs signal processing on the photodetector output signal and generates an output signal corresponding to the contamination level. In another aspect of the invention, the photodetector circuit is incorporated into a Raman gas analysis system.

Abstract: Methods and apparatus for synchronous spectral line imaging are disclosed for use in conjunction with any of a number of radiative analysis techniques such as Raman or fluorescence detection. Light emitted points on a sample are separated into wavelength components and directed onto a two-dimensional image sensor such that the wavelength components impinge along one dimension of the sensor. The other dimension of the sensor is used in conjunction with spatial position relative to the sample, with at least certain of the steps being repeated for the different sample points so as to form the spectral line image. In terms of apparatus, the invention preferably utilizes at least one optical fiber having an input end to receive the light emitted by the sample and an output end to deliver the emitted light to the two-dimensional image sensor. The use of a flexible optical fiber facilitates the movement of the light received from the sample, movement of the received light relative to the sensor, or both.

Abstract: The present invention discloses a method for aligning a reticle with a semiconductor wafer. The method includes the steps of (a) applying a light source and an optical system for directing an incident light beam to a plurality of reticle alignment marks on the reticle to project a reticle-mark beam to an alignment detector therefrom; (b) applying the light source and the optical system for directing the incident light beam to a plurality of wafer alignment marks on a second surface of the wafer for projecting a wafer-mark beam therefrom wherein the second surface opposite a first surface of the wafer facing the reticle; and (c)applying the optical system for directing the wafer-mark beam to the alignment detector for precisely aligning the reticle and the wafer.

Abstract: A spectroscopic detector suitable for detecting oil spills in an aquatic environment includes a buoyant container having an optical window; an optical energy generator mounted in the container for directing an optical energy beam through the window; an optical detector for generating an output signal in response to detecting a second optical energy beam received in the container through the window; and a beam splitter for directing the second optical energy beam to the optical detector. The generation of the optical energy beam and operation of the optical detector may be time gated to reduce thermal noise and isolate the sampled optical energy from background light. The optical energy beam preferably has UV components which inhibits the formation of biological organisms on the optical window.

Abstract: An apparatus and method are disclosed for measuring the concentration of gases that are unstable or difficult contain in a sample cell. A frequency modulated laser is tuned to the frequency of a first spectral feature of a gas of interest and a laser beam is projected through a reference cell containing, at a selected pressure, a selected second gas that has a second spectral feature near the first spectral feature of the gas of interest. The laser is line-locked to an outer zero crossing of a third harmonic of the detected laser beam coincident with the first spectral feature. The concentration of the gas of interest is calculated from a second harmonic of a portion of the laser beam projected through a transmission medium containing the gas.

Abstract: A system for spectroscopic monitoring that includes a broadband source of radiation, structure defining a non-elongate entrance aperture for receiving radiation to be analyzed along a first path; dispersion structure disposed in the first path for spatially dispersing the radiation in the first path as a function of wavelength, structure defining a non-elongate exit aperture for receiving a portion of the dispersed radiation, detector structure for detecting radiation passed through said exit aperture structure, and conical astigmatism reducing reflector structure disposed in the radiation path between the dispersion structure and the exit aperture structure for reducing astigmatism.

Abstract: An apparatus for maintaining an electromagnetic beam, namely a laser beam, aimed at a particular point in space and aligned with a unique propagation path. The apparatus includes one or more adjustable beam steerers located in the propagation path, and first and second spaced apart beam position detectors arranged in the beam path. The beam steerer(s) are preferably adjustable along at least two orthogonal axes of rotation for controlling the propagation direction of the beam. Error signals from the position sensors are fed into a beam steerer controller connected to the beam steerer(s) for electro-mechanically adjusting the beam steerer. The method of the invention involves fixing the propagation path on an angularly adjustable beam steering surface so that the propagation path at a different unique point in space, such as a target, can be controlled by adjusting the angular orientation of that beam steerer.

Abstract: A multi-channel type spectro-photometer not only has a light source, a sample cell to which light from the light source is directed, a spectrometer to which light transmitting through the sample cell is directed, and an array of photo-diodes to which dispersed light from the spectrometer is directed, but also allows the user to specify a range of wavelength within which measurements are to be taken. An optimum charge-accumulating time during which charge is to be accumulated on the photo-diodes array is automatically set according to the range specified by the user. Alternatively, quantity of light received by the photo-diode array may be detected and an optimum charge-accumulating time may be automatically set according to the measured light intensity on the photo-diode array. Dark current and background measurements are taken before a sample is injected into the sample cell and transmitted light therethrough is measured to obtain the absorption spectrum of the sample.

Abstract: A surface position detecting method for detecting a surface position of a surface to be examined, having surface height irregularity, while relatively scanning the surface, is disclosed. The method includes detecting characteristic data related to a surface state at plural measurement positions on the surface, while relatively scanning the surface, and processing the detected characteristic data related to the measurement positions to determine a measurement position for measurement of the surface position in a subsequent surface position detecting process.

Abstract: Small particle identification is disclosed. A high intensity light source provides light at a sensing region for contact with small particles at the sensing region to cause resulting light that includes scattered light and emitted light due to heating of optically absorbing particles to incandescence with the resulting light terminating if vaporization of the optically absorbing particles occurs. A laser, having a laser cavity with the sensing region within the laser cavity, preferably provides high intensity laser light in the laser cavity for contact with the small particles at the sensing region. Utilizing optical detection, predetermined particle characteristic determination is enabled, including particle size and composition of optically absorbing particles.