Abstract: An interferometer system includes an optical radiation source, an optical circulator connected between the optical radiation source and a sample location for transmitting optical radiation from the optical radiation source to the sample location, an output of the optical circulator connected to direct optical radiation to an optical detector. Various embodiments of such a system are possible. A method of performing OCDR or OCT imaging of a sample which involves the steps of: (a) producing low coherence optical radiation; (b) directing at least some of the low coherence optical radiation through an optical circulator to the sample; (c) reflecting at least some of the low coherence optical radiation off of the sample; and (d) detecting at least some of the reflected low coherence optical radiation and producing an electrical signal corresponding thereto.

Abstract: A scanning type projection exposure apparatus including an illumination optical system having a slit which can change an illumination area width in the scanning direction, excluding a portion of this area. The light intensity at a portion located in correspondence with a slit area is detected, and the detection result is used to control the exposure amount with respect to a wafer. The scanning type projection exposure apparatus can control the exposure amount precisely. In the exposure apparatus, the illumination area width in the scanning direction can be changed in order to make uniform the exposure amount in a direction perpendicular to the scanning direction.

Abstract: A method of simultaneously measuring the thickness, group index of refraction, and top and bottom surface profiles of a sample, includes the steps of locating the sample between a surface of a transparent optical flat and a parallel reflective surface such that the respective optical distances between any two of the surface of the optical flat, the top surface of the sample, the bottom surface of the sample, and the reflective surface are distinct and in a known relative optical distance relationship, the distance between the surface of the transparent optical flat and the parallel reflective surface being known.

Abstract: A system for simultaneously inspecting the frontsides and backsides of semiconductor wafers for defects is disclosed. The system rotates the semiconductor wafer while the frontside and backside surfaces are generally simultaneously optically scanned for defects. Rotation is induced by providing contact between the beveled edges of the semiconductor wafer and roller bearings rotationally driven by a motor. The wafer is supported in a tilted or semi-upright orientation such that support is provided by gravity. This tilted supporting orientation permits both the frontside and the backside of the wafer to be viewed simultaneously by a frontside inspection device and a backside inspection device.

Abstract: A structure (22) is located relative to a reference surface (26a, 42) using an optical target (28) affixed to the structure (22) and having a reflective angular-reference hologram (30) thereon with an effective angular orientation. An alignment light beam (38) is directed perpendicular to the reference surface (26a, 42) and incident upon the angular-reference hologram (30) on the optical target (28), and a signal return of the alignment light beam (38) is received at a measurement location. The angular orientation of the structure (22) is adjusted to achieve a signal return of the alignment light beam (38) corresponding to an alignment of the alignment light beam (38) to the effective angular orientation of the reflective angular-reference hologram (30). Multiple reflective angular-reference holograms (30) may be spatially superimposed upon each other in the optical target (28) or spatially separated from each other on the optical target (28).

Abstract: A position measuring device for determining the position of two parts that are movable relatively to one another in the measuring direction, which, in addition, includes the feature of enabling an absolute reference to be established during the measurement. To this end, the position measuring device includes a light source, as well as a beam-splitter element, which splits the beam of rays emitted by the light source into at least one first and one second beam component, which are preferably oriented parallel to one another after leaving the beam-splitter element. Provision is also made for a reference reflector, as well as a measuring reflector, upon which the two beam components strike. A reference marking, as well as a scanning unit are arranged at the measuring reflector and at the reference reflector to produce a reference pulse signal at the position of the stationary reference reflector.

Abstract: A device for in situ real time monitoring of atomic and molecular fluxes by use Rayleigh scattering. The flux can be generated by an effusion cell during molecular beam epitaxy. The present device uses a coherent light source, such as a helium neon laser, a high precision mirror assembly capable of providing an effective number of reflections though the flux beam and an interferometer detector to track the changes in flux.

Abstract: A sensing optical fiber and a sensor system which has both the functions of an optical transmission line and a sensor device and which detects many types of information from the light transmission loss. A sensing optical fiber can detect information with a high detection sensitivity by an OTDR method using Rayleigh scattered light. For this purpose, the sensing optical fiber includes a main line element which is an optical fiber installed as a light transmission line and sensor elements which are relatively short optical fibers that are inserted in intermediate parts of the main line element and whose core diameters are different from that of the main line element. The sensor system is capable of detecting various types of information obtained simultaneously with a high detection sensitivity by an OTDR method using Rayleigh scattered light.

Abstract: In alignment of superpositioned objects on opposing substrates accuracy and simplicity is achieved through relative movement of the substrates responsive to an image of one object reflected from the surface of the opposite substrate. Alignment of mating fine pitch conductors and pads for bonding is achieved by observation of the reflection of one conductor or pad in the surface of the opposite substrate and relatively moving the substrates to eliminate the reflection.

Abstract: A dynamic optical micrometer for measuring the position of a moving object is invented. The optical micrometer includes a laser for generating an optical signal, an RF signal generator, an acousto-optic modulator that is responsive to the optical signal and the RF signal and is operative to provide a first light beam and a second light beam that is up shifted in frequency by the RF frequency, an optical interferometer that reflects the first beam off the object and interferometrically combines the reflected light beam and the second light beam into a heterodyned signal, means responsive to the heterodyned signal and operative to produce an electrical signal at the optical beat frequency corresponding to the RF and means responsive to the RF signal and the electrical signal and operative to provide a linear output signal that corresponds to the position of the object. A method for accomplishing the same is also invented.

Abstract: A double pass etalon based spectrometer. Spectral components of a diffused beam are angularly separated as they are transmitted through an etalon. A retroreflector reflects the transmitted components back through the etalon. Twice transmitted spectral components are focused onto a light detector which in a preferred embodiment is a photo diode array. The spectrometer is very compact producing precise fringe data permitting bandwidth measurements with precision needed for microlithography for both &Dgr;&lgr;FWHM and &Dgr;&lgr;95%.

Abstract: The present invention relates to an optical detector device, in particular for analyzing substances, mixtures of substances or chemical reactions and for determining refractive indices, the device comprising a light source, a measurement path and a reference path and an optoelectronic detection means, with an optical divider being provided downstream of the light source for forming two radiation sources for divergently radiated light beams, of which one is assigned to the measurement path and one to the reference path, and the phase velocity of the light being influenced at least in the measurement path, and the divergent light beams being superimposed in the area of the optoelectronic detection means to form a characteristic intensity distribution.

Abstract: The invention relates to a device and a method for the optical recording of at least one parameter on a longitudinally moved thread-type material. To enable parameters such as the diameter of a thread-type material, the diameter of a yarn package, the hairiness of a yarn etc. to be determined more simply and more accurately, an optical sensor composed of at least two individual sensors (30), in which at least one individual sensor is so constructed and arranged that at least one measured value is recorded digitally for a parameter, is to be used to record in parallel from the material at least two signals, one at least of which is clocked.

Abstract: The present invention provides a method and associated apparatus with which it is possible to implement both shape detection and also displacement measurement in particular using partially identical working steps. A method according to the invention for determining the displacement of at least a part of the surface of a measurement object between an initial condition and a measurement condition and the shape of that surface of the measurement object is characterized in that the operation of determining the shape and the operation of determining the displacement are effected with the same measurement method using the speckle effect.

Abstract: An apparatus that can measure a space between a first surface and a second surface such as the air bearing between a slider and a disk. The apparatus may include a light source that can reflect a light beam from the slider and the disk. By way of example, the light beam can be reflected off of an Al2O3 cap of a slider. A birefringent element such as a Savart plate may split the reflected light beam into an ordinary beam and an extraordinary beam. The ordinary and extraordinary beams may combine to form an interference pattern that is detected by a photodetector. A controller receives data from the photodetector. The apparatus may have a mechanism which can vary a phase between the ordinary and extraordinary beams so that the controller can calculate a phase value &phgr;. The controller then computes the space from the phase value &phgr;. The variation in phase between the beams may be created by tilting the birefringent element, or moving the reflected light beam directed into the birefringent element.

Abstract: A liquid drop detector which may be fixed or attached by a simple operation, without machining, to a window glass, includes a light emitting element, a light receiving element and light guiding bodies wherein the light emitted by the light emitting element is introduced through a diffraction grating into a first light guiding body and after undergoing total internal reflection within the first light guiding body it is introduced through a silicon member, through an elongated light guiding body, through an additional silicon member, and into a windshield. After traveling within the windshield by total internal reflection, the light passes through a silicon member, reenters the elongated light guiding body, passes through another silicon member and enters a second light guiding body which guides it to a receiver.

Abstract: A signal processing circuit for a reference signal occurring in a heterodyne interferometer and a measured signal. The underlying frequency modulation of the radiation source of the heterodyne interferometer results in phase jumps in both signals. Signal filtering of both the reference signal and the measured signal with a gate signal removes from both signals those signal components that have the same phase sign. Further simplification of the signal processing results from signal interpolation by band pass filters and signal down-mixing into a lower frequency range below the heterodyne frequency. The input signals processed by the circuit can be further processed by a conventional phase comparator.

Abstract: In accordance with the invention, an improved optical assembly having a monolithic structure is provided. The monolithic optical assembly is useful in interferometers to achieve a fringe effect in a Fourier transform spectrometer, and comprises top and bottom members which are joined into a monolithic structure by first and second support members and a beamsplitter. The assembly also comprising a first reflecting assembly in reflecting relation with the beamsplitter. An alternate embodiment of the invention has an added reflecting assembly in reflecting relation with the first reflecting assembly and the beamsplitter assembly, which allows for the use of multiple wavelength light sources to achieve a fringe effect in a Fourier transform spectrometer.

Abstract: A colorimetric red blood cell sensor provides an automatic system for deting and preventing the further mixing of red blood cells and plasma. The sensor includes a processor that controls blue and red light sources so that they collectively generate pulsed blue and red light signals that are directed through blood serum held in an optically transparent container. The red and blue signals are 180 degrees out of phase, and hence staggered, with respect to each other. A photodetector system detects the pulsed red and blue light signals and generates output signals representing the intensities of the staggered signals received by the photodetector system. A microprocessor determines the ratio of the intensities of the red and blue light signals detected by the photodetector system. If the ratio exceeds a limit, the microprocessor generates a fluid control signal that prevents further mixing of red blood cells and plasma.

Abstract: Since disks of the same type are loaded in a disk device using a conventional disk changer scheme, the disk device is not versatile as a peripheral device of a computer. ROM disks and RAM disks are mixed and stored in a magazine, and this magazine is loaded in the disk device. In the disk device, a tray is identified in step by a detector arranged on the tray to check whether the tray be a ROM disk or a RAM disk. Thereafter, discrimination information is recorded, together with the contents information, on an IC memory arranged on the magazine in step. Thereafter, when the magazine is loaded again, the discrimination information is read from the IC memory, and an operation corresponding to each disk is performed.