Abstract: A fiber optic magnetic field sensor employing Faraday effect. The sensor has two pieces of birefringent substance interposed between the ends of optical fibers and a rod lens for effecting polarization separation. In addition, the sensor employs a reflex optical system in which light reciprocates through a Faraday material. Thereby, a magnetic field sensor has been realized which is more compact and lightweight and lower in cost as well as more accurate.

Abstract: An apparatus and method are disclosed which monitor the position of a scanner platform and, in response to roll of the platform, compensate a scanner device mounted thereon to maintain the center lines of the angles of scan in alignment as defined by a line parallel to the direction of movement of the scanner platform relative to the object which is scanned.

Abstract: A read/write system which reduces access time in optical disc apparatus is disclosed. The head includes an array of lenses which covers a substantial portion of the radius of the disc. Access of a particular disc track is achieved by deflection of the reading beam, rather than by any physical movement of the head. For read-out, the array focuses light reflected from the disc onto a corresponding array of photodetectors.

Abstract: The present invention is directed to an improvement in an alignment system for a scanning mask aligner employing a pattern on the mask or the wafer or both in the scribe lines that run in the direction of scanning, the improvement comprising a viewing system having optical grids, a system for moving the patterns across the optical grids in the viewing system, the grids corresponding to the directions and spacings of the patterns so that light transmitted through the grid is strongly modulated, and circuitry for comparing the phase modulation from the mask and wafer alignment targets to obtain alignment error signals; further according to the invention, the same system used to measure alignment can also be used to measure how well the mask is focused on the wafer.

Abstract: The invention contemplates a beam splitter which consists of a phase grating (5) which transmits at zero order the greatest part of the radiation of a two-mode laser (1) and which diffracts a relatively small part of the radiation, symmetrically at 1 order and -1 order, respectively. The intensity of components of the radiation polarized perpendicular to each other and associated with the two modes is measured by detectors (11, 12) in front of which polarization sheets (9, 10) are arranged as analyzers, and outputs of the detectors are used to regulate the center frequency of the laser tube (1).

Abstract: This invention describes novel method and apparatus for inspecting gear geometry via optical triangulation. Preferred machine construction uses specialized geometrical relationships of sensor to gear, and specialized high accuracy photodetector array based laser triangulation sensor units of large range and high response speed.

Abstract: An elongated light receiving element is formed with a plurality of parallel one dimensional light receiving arrays or lines, each of which is lead out from a substrate. Each line is tested to determine which line or lines are free of defects, and the remaining lines are disconnected from the power source. The device serves to increase the production yield of such devices, which are prone to defects when manufactured in large sizes.

Abstract: A photo-sensor, such as a photo-diode, is applied to the converging area of a flat type light transmission unit in an image read-out system, thereby intercepting a part of the scan light which falls on and travels through the light transmission unit after being reflected from an image-bearing sheet. The output signal from the photo-sensor can be advantageously used to detect arrival of the sheet edge at the scanning station, any scratches on the sheet and other operating conditions as required.

Abstract: A tracking error of a light spot focused on an optical record disc by means of an objective lens with respect to an information track recorded on the disc is detected by processing outputs from a light detector arranged in a far field of the track and having four light receiving regions on which a light reflected by the disc is incident. A tracking error signal of a differential detection system, i.e. a difference between two sums of outputs from two pairs of two regions aligned in a direction tangential to the track is derived, and a push-pull signal, i.e. a difference between two sums of outputs of two pairs of two light receiving regions aligned in a radial direction is also obtained.

Abstract: Disclosed is an original reading device in which, of first and second areas of the portion to be read of an original to be read which adjoin each other with a boundary therebetween, the first area is projected upon a first image pick-up element by a first lens and the second area is projected upon a second image pick-up element by a second lens, whereby the first area and the second area are read by the first element and the second element, respectively. The first and second lenses are disposed at positions corresponding to positions more toward the boundary between the first and second areas than the centers of the first and second areas.

Abstract: A safety device for detecting troubles in an optical transmission fiber of a medical laser application to prevent accidents characterized by using either a laser light reflector from the exit end surface of the fiber or a secondary light. When trouble is detected, the safety device operates a mechanism for interrupting the coupling of a beam of laser light into the transmission fiber. The safety device includes an electrical circuit which allows appropriate use of the apparatus with the tip of the fiber in water or a physiological salt solution for treatment of a tumor in a urinary bladder. The electrical circuits will include amplifiers, comparators and logic circuits.

Abstract: An optical flex sensor is provided and consists of a flexible tube having two ends, a reflective interior wall within the flexible tube and a light source placed within one end of the flexible tube and a photosensitive detector placed within the other end of the flexible tube to detect a combination of direct light rays and reflected rays when the flexible tube is bent.

Abstract: A fail-safe system for monitoring a condition and activating controls in response either to the non-existence of that condition or the failure of any component in the system, in which a preliminary fail-safe oscillation train derived from sensing the condition is converted into a steady state indication of that condition, and a secondary fail-safe oscillation train is generated in a fail-safe way from said steady state indication for further transmission downstream for control purposes. In the context of flame monitoring, means associated with the preliminary oscillation train are provided for discriminating between separate flames and for time delay purposes.

Abstract: A passive optical switch for an automatic door for opening and closing a door comprises a light receiving portion provided with a segmented light receiving surface formed by a number of the optical fiber fluxes so as to be adjusted to the focus of a lens, a phototube cell converter portion connected to each of the optical fiber fluxes extending from said light receiving portion, a voltage change detecting portion for detecting the change of an output of said phototube cell converter portion and a direction discriminator circuit for analyzing a detecting signal emitted from said voltage change detecting portion, whereby an automatic opening and closing of a door may be effected by discriminating onward movement of a passing body by detecting the change of an output emitted from said phototube cell converter portion caused by a passing body.

Abstract: An electrical isolation system formed of a pair of optically interconnected emitter-receiver systems of similar character disposed in input and output loop circuits with associated means to balance a signal induced current in the input loop with a control induced current in the output loop circuit.

Abstract: The machine comprises a device for shifting the track which is controlled by a device for the detection of its geometrical defects.The detection device comprises three rail feelers to which there are connected a light-ray emitter (17), a screen (18) having two parallel delimiting edges (19, 20) and a receiver (21) having two identical photovoltaic cells (22, 23) arranged in such a manner that the sum of their irradiated surfaces (u+d) is a constant and their difference (u-d) is proportional to the displacements of the screen.The signals produced by the two cells are processed in an electronic circuit comprising a totalizer (28) delivering a signal for the control of the displacement device proportional to the said difference (u-d) and a piloting circuit (30, 41, 42) of the emitter to maintain the irradiation of the two cells constant by comparison of a signal proportional to the said sum (u=d) with a reference signal (S.sub.0).

Abstract: In a photoelectric converter-type pulse encoder comprising a light-entrance portion (13, 13'), a rotating slit plate (12) on which a lattice plate receiving light from the light-entrance portion (13, 13') is formed, a fixed slit plate (11) on which a lattice plate arranged to face the lattice plate of the rotating slit plate is formed, and a light-receiving portion (14, 14') arranged below the fixed slit plate, light is emitted from a light-emitting circuit to the light-entrance portion (13, 13') through the light fibers (17), and the light received by the light-receiving portion (14, 14') is introduced into a light-receiving circuit through the light fibers (17), thereby adjustment of the amount of light is made easier, the pulse generation in response to the rotating speed is ensured, and the rotating speed is detected with a high precision.

Abstract: A photodetector output circuit comprises a plurality of adjacent photodetectors grouped into pairs having first and second photodetectors for generating signals indicative of levels of light falling thereon, a first shift register for receiving the signals from the first photodetectors in the pairs, a second shift register for receiving the signals from the second photodetectors in the pairs, and a pair of first and second sample and hold circuits for successively sampling and holding outputs from final stages of the first and second shift registers, respectively. A comparator receives as inputs outputs from the first and second sample and hold circuits for delivering out signals when the received inputs have a level difference of a predetermined value or higher. With this arrangement, the photodetector output circuit can produce digital signals indicative only of abrupt changes in the level of incident light and excludes any influence due to gradual light level variations which would result from shading.

Abstract: An arrangement of partially reflecting mirror surfaces to extend the dynamic range of area sensor arrays as used in optical measurement systems. An instantaneous optical AGC allows a single area sensor to be used in inspection systems where surface reflectivities and characteristics may vary from diffuse to mirror-like. The partially reflecting mirrors instantaneously superimpose on the area sensor a set of spatially displaced energy related images of the inspection pattern. Electronic readout of the sensor and subsequent data processing allows selection of portions of each image which represent the linear non-blooming operating range of the sensor.

Abstract: A fire detection system using optical fibers to transmit flame signals from a plurality of remote monitoring stations to a central detection and analysis station, the invention comprises a network of optical fibers which connect the monitoring stations to the central detection station for the purpose of transmitting incident analog optical, infrared and ultraviolet spectra to the central station for detection of fire conditions. The central detection and analysis station preferably includes a rotary scanner which scans each of the optical fibers, light from the fibers being dispersed by a prism associated with the scanner to allow detection of the various spectral components of the dispersed light by light sensitive semiconductors. The detected spectral components are then compared to known fire signal signatures which include flicker rate and spectral content information.