Abstract: A method and apparatus for inspecting patterned transmissive substrates, such as photomasks, for unwanted particles and features occurring on the transmissive, opaque portions and at the transition regions of the opaque and transmissive portions of the substrate. A transmissive substrate is illuminated by a laser through an optical system comprised of a laser scanning system, individual transmitted and reflected light collection optics and detectors collect and generate signals representative of the light transmitted and reflected by the substrate as the substrate is scanned repeatedly in one axis in a serpentine pattern by a laser beam which is focused on the patterned substrate surface. The defect identification of the substrate is performed using only those transmitted and reflected light signals, and other signals derived from them, such as the second derivative of each of them.

Abstract: A spectrometer is described with a new intensity detector for electromagnetic radiation. The detector comprises means for detecting the deflection of a cantilever which has a bimetallic/bimorph structure. The deflection is proportional to the absorbed amount of radiation.

Abstract: The invention relates to a procedure for determining an identification of a sample of material, or its properties. Electromagnetic radiation from a radiation source (1) is reflected or transmitted through the sample. The radiation from the sample is collected and analyzed over several channels (7, 7', 7"), which modulate the radiation with a spectral transmission function which is unique for each channel. The modulated radiation is transmitted to one or several detectors (9, 9', 9") which produce output signals which are further electronically processed. The spectral range of each of the individual channels is common to all of the channels. Within the common range the channels are provided with different spectral transmission functions (7, 7',7") which are optimally chosen for a given application.

Abstract: A new concept of gyroscope utilizing self-modulation is introduced in a frame of a solid state ring type laser. The inventive solid state ring laser system includes a base, a laser pumping source, an active medium, a focussing unit, a detector, a magnet and a cover, wherein the magnet having an appropriate magnetic field strength to distinguish the direction of rotation and to increase the sensitivity. In the inventive gyroscope, a direct sensing of rotation is made by measuring the self-modulation frequency without complex signal processing by using a frequency counter.

Abstract: In an optical fiber testing method, light are supplied to a measuring optical fiber so that return light, consisting of back-scattering light and Fresnel-reflection light, is outputted from the measuring optical fiber. A waveform representing the return light is used to perform testing of the measuring optical fiber. Herein, a detection range of the waveform used for detection of connections is defined and is partitioned into a plurality of regions in connection with Fresnel-reflection space. Then, at least a noise index and a constant are calculated for each region; and HOUGH conversion is performed on each region of the waveform. In addition, a center-value filtering process is performed, using the constant, with respect to each region of the waveform to create a filtered waveform. Further, a mean difference process is performed on the filtered waveform to create a mean difference waveform.

Abstract: A fluorescence dot area meter for accurately measuring halftone dot area on a printing plate having an emulsion containing one or more fluorescent compounds. The fluorescent dot area meter generally includes an illumination source for providing light having a first range of wavelengths, a system for exposing the printing plate to this light to cause the printing plate to emit light (fluoresce) within a second, higher range of wavelengths, and a system for determining halftone dot area based on a measurement of the light emitted by the printing plate.

Abstract: A wavelength measurement system is provided which allows the very accurate measurement of wavelengths in a relatively small predetermined range. A transmission ratio is formed consisting of the power of an optical signal which has passed through a thin-film interference filter divided by the power of a control signal. A table look up is performed in a stored transmission ratio wavelength table. The system is also used in a self stabilizing laser, and a spectrometer.

Abstract: An optical fiber monitoring method and apparatus is described for monitoring the signal loss within an optical fiber during installation of the optical fiber. The apparatus contains a jig for advancing the optical fiber along a predetermined path, a light source for transmitting light signals along the optical fiber, and a light sensor for detecting the light signals. The detected light signals are converted to an audible signal having a frequency which varies in relation to the detected signal. An audio transducer then outputs the audible signal. Since the frequency of the audio signal is a measure of the signal loss along the optical fiber and, therefore, is a measure of the amount by which the optical fiber is bent during the installation process, the audible signal can be monitored in an "eyes-free" manner to detect excessive bending of the optical fiber in order to prevent damage to the optical fiber during installation.

Abstract: A method of analyzing the concentration of components in a fluid solution that can be contaminated with gas bubbles includes applying a spectrum of light to a test cell holding a sample fluid solution and detecting the measurement of the intensity of light passing through the test cell. A gas of the type that would be found in the sample fluid solution can be initially inserted into the test cell with light of a predetermined range of wavelengths scanning the test cell to obtain a reference spectrum. The test cell is then filled with the sample fluid solution and the light measurement is again conducted to obtain a sample spectrum. Data processing can occur to derive a light absorbance spectrum from the reference spectrum and sample spectrum to enable a determination of the percentage of concentrations of each component from the light absorbance spectrum, including the percentage of gas.

Abstract: An apparatus for analyzing a body-fluid sample, such as a urine sample, disposed on a reagent pad is provided with means for illuminating the reagent pad on which the body-fluid sample is disposed, means for detecting light received from the reagent pad and generating a first reflectance signal at a first time and a second reflectance signal at a second time, and means for assigning a color to the body-fluid sample based upon the magnitudes of the first and second reflectance signals. The means for assigning the color to the body-fluid sample may include means for determining a pair of color coefficients each of which has a magnitude based upon the magnitudes of the reflectance signals and means for assigning the color to the body-fluid sample based upon the magnitudes of the color coefficients.

Abstract: An apparatus for inspecting an end surface of a fiber optic is provided having a scope body with an adapter that mates the scope body with a bulkhead connected to an end surface of a fiber optic, and a system for generating light at a selected angle to the end surface of the fiber optic, located within the scope body, so that the light impinges on the end surface of the fiber optic through the bulkhead at the selected angle. An image of the end surface of the fiber optic is generated wherein an imperfection located on the end surface of the fiber optic casts a shadow on the image of the end surface of the fiber optic. The image is received by an image receiving system wherein the imperfection on the end surface of the fiber optic is detected and enhanced due to the shadow in the image. A method for inspection an end surface of a fiber optic is also disclosed.

Abstract: In the method of measuring a distribution of zero dispersion wavelengths in an optical fiber in a longitudinal direction, an optical pulse and a pump light are launched into the optical fiber. A gain generation portion of the optical fiber which indicates that the optical pulse power is amplified based on modulation instability induced by the pump light is detected from a back-scattered light waveform of the optical pulse indicative of an optical pulse power distribution in the longitudinal direction of the optical fiber. A zero dispersion wavelength of the gain generation portion of the optical fiber is determined from the pump light wavelength.

Abstract: A spectral imager or spectrophotometer-type optoelectronic camera including an optical system, a CCD-type set of photosensitive elements (3) at the focus of the optical system, a transparent protective window (5) arranged in front of the sensitive face (4) of the set of photosensitive elements (3), and a spectral disperser (1) allowing spectral analysis of the scene observed by the camera. The sensitive face (4) of the set of photosensitive elements (3) that points toward the protective window is coated with a monolayer or multilayer coating of anti-reflection material (9) whose thickness (e) varies continuously as a function of the wavelength of the light received by the sensitive face, parallel to the dispersion axis of the disperser (A).

Abstract: System and method for temperature resolved molecular emission spectroscopy of solid, liquid or gaseous materials are described wherein a sample is vaporized and decomposed, and the vaporous sample is transported into a combustion flame; a spectrum of intensity of the optical emission from the flame at a selected wavelength versus temperature of the sample define molecular peaks which are characteristic of the sample material and allows both qualitative and quantitative analysis of the sample.

Abstract: The present invention is a device which may be used to detect the presence of light in a single mode optical fiber while the optical fiber is in use, or to introduce light into an optical fiber. The device includes an identifier chip, and an associated, complementary shaped plate, each of which employ both microbending and macrobending portions. The chip and the plate are each formed of a single piece of material, although only the chip must be formed of an optically transmissive material. In use the chip is urged toward the plate with an optical fiber therebetween. Deformation of the fiber caused by the stress exerted by the chip and the plate will cause detectable light to be emitted through the chip if the fiber is live.

Abstract: A multimode optical time domain reflectometer has first and second wavelength optical transmitters for launching optical pulses into a fiber under test and optical receivers responsive to the respective wavelengths for converting the optical return signals from the test filer into electrical signals for acquiring waveform data representative of the optical return signals at the respective wavelengths. A processor receives the waveform data and determines a difference in fiber slopes between the optical return signal at the respective wavelengths and adds the fiber slope difference to the waveform data of the second optical return signal for producing composite waveform data having a uniform fiber slope for the waveform data acquired at the first and second wavelengths. A multimode optical time domain reflectometer of this design provides improved two point resolution for 1310 nm testing of multimode optical fiber.

Abstract: A color classification apparatus for classifying the color component of a target object includes an imaging optical system, an image pickup device, optical bandpass filters, a transmission wavelength selection unit, a storage unit, a read unit, and a correction unit. The image pickup device is arranged on the imaging plane of the imaging optical system. The optical bandpass filters are optically arranged upstream the image pickup device, and have a plurality of different selectable optical transmission wavelength bands. The transmission wavelength selection unit selects one transmission wavelength band from the plurality of optical transmission wavelength bands.

Abstract: A differential spectrometry system detects very narrow-band spectral features, while providing much higher optical transmittance and signal-to-noise ratios than prior optical-filter-based spectrometer systems. A plurality of light detectors (10a, 10b) detect light that falls within respective wide wavebands. The wide wavebands have overlapping and non-overlapping portions, one of which is the desired narrow waveband. The detector outputs are operated upon to produce an output signal (22) which includes substantially only the desired narrow waveband. In the preferred embodiment, the light detectors (10a, 10b) are implemented with a pair of optical detectors (30a, 30b) and respective optical interference filters (24a, 24b). The filters have substantially identical cut-off wavelengths (.lambda..sub.2) and cut-on wavelengths that are shifted by .DELTA..lambda. with respect to each other (.lambda..sub.1 and (.lambda..sub.1 +.DELTA..lambda.), respectively).

Abstract: Measurement device, for the colorimetric measurement of a display screen. The device includes a first lens which forms the image of the Fourier transform of the elementary surface to be measured. An optical system is used to form a second lens which projects the image of the transform onto a set of detectors. The second lens (10) comprises an input lens (11) after the image plan (Fi) of the first lens (1), a colour filter (12) formed by filters (12l) which are associated with each colour, an output lens (13), downstream of the colour filter (12) for focusing the beams onto the detectors (7i, J) of the sensor (7), and a processing circuit (18).

Abstract: An optical scatterometer system enables illumination of a sample material at various angles of incidence without rotating or otherwise moving the sample material.