Abstract: A spectroscopy method is defined in which a first source of radiation (51) emits a periodically pulsed beam (A) having a repetition frequency .omega. and in that a second source of radiation (52) emits a periodically pulsed beam (B) having a repetition frequency .omega.+.DELTA., the beams are united with each other and directed at a material specimen (6) to be analyzed and a detector means determines the amplitudes of the frequency components n.DELTA. of the beam emanating from the material specimen.

Abstract: A position detecting system, for detecting a position of an object, includes a light detecting device having arrayed light detecting elements, a moving mechanism for producing relative movement between the object and the light detecting device, and a control device for causing the moving mechanism to produce relative movement between the object and the light detecting dvice of a predetermined unit amount and in a predetermined position detecting direction, and also to cause the light detecting device to detect, at respective positions, light from a mark formed on the object, wherein the control device calculates mark positions from signals obtained at the respective positions, and also determines the position of the object on the basis of the calculated mark positions.

Abstract: A spectrophotometer which is highly manufacturable at minimum cost nevertheless provides precision of measurement of spectra components of light which is projected therein by maintaining precise optical alignment of optical and electrical components thereof. These components are mounted in a module which is contained in a housing having an entrance aperture which defines an object area for light the spectrum of which is measured by a photodetector in the module at an image area. The module has a base plate provided by a printed circuit board on which a closed wall encompasses an area (a corral) on one side of the circuit board. The wall is a one piece structure which extends to the vicinity of the edge of the board. It is assembled with the board as a unitary structure so that the assembly is made torsionally rigid and resists bending in the plane of the board. The module may be of sufficiently small size so as to be located in a housing which is hand held, thereby providing a hand-held spectrophotometer.

Abstract: A system for the determination of the distance and orientation of an object carrying at least three light sensors from a fixed reference point when the object is irradiated by two modulated scanning beams of known angular orientation and rotational frequency. Timing circuitry located in the control processor determines the time interval .DELTA.t, between successive interceptions of the object by each of the beams. Knowledge of this time interval and the scanning beams' relative positions and angular orientations permits calculation of the object's spatial coordinates. The optical beams utilized are fan-shaped in cross-section. The method of operation is also disclosed.

Abstract: An instrument and a method are provided for determining the concentration of at least one species in a substance. The instrument and method can be used to identify and distinguish among various degrees of contamination of motor oil, diesel fuel, and hydraulic fluid by water, ethylene glycol, wear particles, and loss of anti-oxidants. The instrument includes a broad band light source, such as a tungsten filament incandescent lamp, which is very inexpensive and reliable. A fiber optic link is provided to a detector that receives and discriminates among optical spectral transmissions through the fiber optic. Discrimination circuitry is provided for evaluating the transmission and providing a readout that indicates the quality of the fluid. The instrument is suitable for in situ determination of oil quality.

Abstract: A non-contact substrate alignment system for a lithography system is disclosed that comprises three substrate edge detectors. Each edge detector comprises a projector, preferably located above the substrate, that projects a light field down onto a substrate and a stage. The light field has a predetermined shadow line that is straight and runs perpendicularly to the direction of the substrate's edge. A camera is also located above the substrate and detects the light from the light field. The height differential between the substrate and stage causes a shift in the shadow line from the perspective of the camera. A controller connected to the camera utilizes this shift to locate the edge of the substrate. The problems associated with the mechanical banking techniques are thus avoided. Moreover, the technique uses detectors and projectors that can be located entirely above the substrate; specially designed stages with incorporated detectors or projectors are not required.

Abstract: An illumination system is provided having one or more light sources, opaque baffles, and mirrors for illuminating indicia on a substrate, such as a semiconductor wafer, for viewing by a camera aligned parallel with or at an angle to the substrate. The light sources include light emitting diodes (LEDs) for illuminating soft marks and broad spectrum incandescent lamps for illuminating hard marks. Dark field and light field illuminators are provided for enhanced reading of light indicia on a dark background and dark indicia on a light background, respectively. A light control unit allows for manual or automated control of light source selection and light intensity. Opposing mirrors extending along the optical paths of the light sources, reflect light emitted from the light sources into the camera field of view, thereby increasing the illumination efficiency and permitting the use of fewer light sources.

Abstract: A time resolved spectroscopy system and method are provided using digital processing techniques of a low power, continuous wave signal generated by a continuous wave light source, such as a cw laser. Time elapse is determined by measuring the time shift of the signal modulation sequence using the cross correlation of a return signal with the reference signal. The high resolution time delay is introduced at the start of each modulation cycle and the high resolution measurement is constructed by interlacing a data set based on the delay information. The high resolution TRS or fluorescence measurement is achieved by correlation calculation of the measured data and the reference code and deconvolving the autocorrelation function of the reference code.

Abstract: A projection exposure apparatus employs light in two different wavelength bands for exposure of a photosensitive substrate and for alignment of the substrate with a mask, respectively. The mask has a window through which alignment light is passed to an alignment mark on the substrate and has a shield for preventing illumination of the alignment mark by exposure light. In one embodiment the position of the shield relative to the window is determined by magnification chromatic aberration of a projection optical system with regard to the alignment light. In another embodiment the path of the alignment light through the window is inclined relative to a line perpendicular to the mask and passes through a pupil of the projection optical system at a point deviated from the center of the pupil.

Abstract: A spectrophotometer system includes an optics block housing an excitation lamp and a cell for receiving a gas to be detected. The excitation lamp excites atoms of the gas to be detected to produce photons. The spectrophotometer system also includes a photo-multiplier tube assembly and an analog-to-digital converter. The photo-multiplier tube assembly detects the photons, and produces an analog output accordingly. The analog-to-digital converter converts this analog output to a digital output. The photo-multiplier tube assembly and the analog-to-digital converter of a spectrophotometer system are calibrated together so that a zero input to the analog-to-digital converter may be defined as an absence of photons. The optics block is configured to minimize scattering of light, without a lens, so that the output of the spectrophotometer system is a function of the number of atoms of the gas to be detected and not of scattered light.

Abstract: A position detecting system and method for detecting the relative positional relationship between first and second objects disposed opposed to each other includes providing first and second marks on first and second objects, respectively, and irradiating one of the first and second marks with light from an irradiating light source. In addition, the other of the first and second marks is placed out of an irradiation region of the irradiating source and first diffraction light diffracted by one of the first and second marks is detected. Next, a first signal corresponding to the light intensity distribution of the first diffraction light is stored in memory. Both the first and second marks are then irradiated with light from the irradiation source and second diffraction light diffracted by both the first and second marks is detected. Next, a second detection signal corresponding to the light intensity distribution of the second diffraction light is stored in memory.

Abstract: A distance measuring apparatus has: light receiving means for receiving light which is emitted from a light emitting element unit and reflected from an obstacle having a reflecting surface, a pair of members of high reflection performance being respectively disposed on portions of the reflecting surface; and a calculating circuit for calculating a distance from the obstacle on the basis of a time period between the emission and the reception of the light. According to the apparatus, in a measurement range of a short distance where light reflected from a reflecting surface positioned between the pair of members of high reflection performance is received, the maximum amount of light received by the light receiving means is set to be smaller than a sensitivity at which a snowfall is detected, and the minimum amount of light is reduced to a level at which an obstacle positioned at the short distance can be detected.

Abstract: A rotational hyper-spectral imager is disclosed. The rotational hyper-spectral imager collects substantially all available photon flux emitted by an object being detected and analyzed and allows the rotational hyper-spectral imager to determine the composition of the objects. The rotational hyper-spectral imager is particularly suited to detect and analyze objects having weak illumination.

Abstract: A spectrometer construction incorporates a single lens system (11) to both focus light input to the spectrometer on a diffraction grating (9) and to focus the light dispersed by the diffraction grating into separate spectral constituents back through that lens onto an image plane (15) for processing. Ordinary photographic lenses with fast lenses of f2 or better are able to serve as the lens system, thereby providing a higher quality system at lower cost than previously possible. With the light path doubling back through the spectrometer lens the space required for a spectrometer's optical system is reduced and results in a more compact spectrometer.

Abstract: Method and device for ascertaining the spacing of the center line of curvature of a concave body surface 3a and 5a, which is curved in the shape of a conical envelope, in particular the spacing of the longitudinal center line of a turbine rotor bearing or the central opening in the rim of a turbine impeller wheel from a reference axis. A sharply focussed light beam L, which presets the reference axis, is emitted by a light beam transmitter 6 through the measurement space which faces the body surface 3a and 5a to be measured. This light beam impinges on the measurement field of a photo-electronic position detector rigidly fastened at a sensing device 7. The sensing device 7 is supported in stable manner and displaceably on the body surface 3a and 5a to be measured and is rotated about the center line of curvature of the body surface through displacement of its supported end in the direction of curvature on the body surface.

Abstract: A position detection apparatus and method detects the relative positional relationship between first and second objects facing each other in a facing direction. First, second and third marks each serving as a physical optical element are provided on the first object, while a fourth mark serving as a physical optical element is provided on the second object. A light projector projects light onto the first and second objects A light detector detects a first light beam diffracted by the first mark and reflected by the second object, a second light beam diffracted by the second mark and reflected by the second object, and a third light beam diffracted by the third and fourth marks. A first position detector detects the relative positional relationship between the first and second objects in the facing direction based on signals representing the first and second light beams from the light detector.

Abstract: A wavelength-scanning mechanism for a spectrometer utilizes an eccentric disc cam driven by a pulse motor to pivot a diffraction grating with a contact bar fixed thereto. A light source supplies light to the mechanism with a first concave spherical mirror reflecting light to the diffraction grating and reflecting light reflected by the diffraction grating to a zero-order light detector. A second concave spherical mirror reflects light diffracted by the diffraction grating to a diffracted light detector. A controller receives information from the light detectors and controls the pulse motor. At least one cam follower is mounted on the cam at a position eccentric from the rotational axis thereof and slidably contacts the contact bar. Alternatively, the diffraction grating has two contact bars fixed thereto, and the cam follower is pivoted between the contact bars.

Abstract: A simultaneous multi-element atomic absorption spectrometry system includes a light source, a furnace, a spectrometer, and a random access charge transfer device. The furnace creates vapors of a sample contained within the furnace. The light source passes a light beam through the furnace so that wavelengths of the light beam corresponding to spectral lines of multiple elements contained in the vapors are absorbed by the vapors. The spectrometer receives the light beam after the light beam has passed through the furnace, and disperses the light beam into a spectrum. The random access charge transfer device receives the light beam after the light beam has passed through the spectrometer, integrates and stores charge corresponding to the intensity of the light beam, and randomly accesses for readout subarrays of the random access charge transfer device corresponding to spectral lines of the multiple elements.

Abstract: An optical method and apparatus is provided for determining the color and profile of a target surface of an object. The target surface is scanned with an incident beam of light containing a plurality of wavelengths including at least one well defined wavelength. A return beam reflected from the target is split into at a first and second return beam. The first return beam is utilized for detecting the profile of the target surface; and, a plurality of detectors are provided that detect color information corresponding to the target surface from the second return beam.

Abstract: A broadband optical detector is disposed to measure the total intensity I(.lambda., .alpha.) attributed to a portion of the optical spectrum passed by a sharp bandgap optical transmission element as the bandgap is caused to translate over a desired wavelength interval by a band gap control parameter, T. The differential spectrum of the incident optical radiation is recovered by the differentiation of I(.lambda., .alpha.) in respect to the parameter T.