Abstract: In an apparatus for determining the concentration of foreign substances in a stream of water, a liquid stream is derived from lines preceding and following the pipeline block for the process and each is pumped into a cell, a radiation source being associated with each of the cells, whose beams penetrate the cells and are delivered both to a first detector and to a second detector. A beam filter is placed in front of each of the detectors and divides the beams into two beams of different wavelengths. Between the beam source and the two cells a revolving chopper wheel is disposed which alternately deflects the beams of the radiation source into one and the other cell, while the electrical signals of the detectors are compared with one another by an electrical circuit and processed to an identifying signal.

Abstract: The invention relates to a method of measuring the optical radiation energy reflected by a reflection place as a relative fraction of energy supplied by an optical transmitter via an optical line. Using few components, reliable and constantly exact measuring values can be obtained in that the optical line (12,25) is connected to a backscattering measuring device (1) (OTDR) which transmits radiation in known manner via an optical connector (5) and which comprises a reception and evaluation device (6 and 7, respectively) for forming a measuring value which is proportional to the optical power backscattered in the optical connector (5) of the backscattering measuring device (1) and in that a reflection element (17, 19) having known reflection factor R.sub.N is arranged in the optical path between the connector (5) of the OTDR (1) and the end of an optical path comprising the reflection area (9) to be examined.

Abstract: An exposure apparatus includes an imaging optical system to project, in sequence, images of a pattern of an original upon different regions of a workpiece, the imaging optical system having an optical axis, a detecting system to irradiate a predetermined portion of a first region of the workpiece to detect the position of the first portion with respect to a direction of the optical axis of the imaging optical system, a workpiece carrying stage for carrying thereon the workpiece and being movable in a plane perpendicular to the optical axis, the workpiece carrying stage being movable to allow detection of the position of the first region with respect to the direction of the optical axis by the detecting system and the projection of the image of the pattern upon the first region by the imaging optical system, an aligning system to bring the position of the first region with respect to the direction of the optical axis into coincidence with the image of the pattern projected by the imaging optical system, and a

Abstract: An electromagnetic radiation detecting device comprises at least one radion detector for detecting electromagnetic radiation from a hemisphere, a radiation-transparent protective hood covering the or each detector, and a rotary chopper to alternately shield the or each detector and associated hood from arriving radiation and to expose the detector and hood to such radiation. The chopper comprises a carrier disc, which is rotatable about an axis parallel to a radiation-receiving area of the or each detector, and at least one hollow semicylindrical shielding member fixed at the periphery of the disc and curved in the axial direction of the semicylindrical shape. The or each shielding member is movable on a circular path by the disc to alternately shield and reveal the hood covering the or each detector.

Abstract: An optical interference filter has narrow linewidth and wide acceptance ae and includes a hemisphere coated to provide a narrow bandpass filter at a desired wavelength at normal incidence while other wavelengths at normal incidence are absorbed or reflected. A photodetector placed at the center of the hemisphere detects the desired wavelength only. Other wavelengths that are shorter than the wavelength of the filter are transmitted through the filter to be absorbed by a black absorbing surface around the photodetector. Thus, only the frequency of interest at normal incidence provides a representative signal at the detector.

Abstract: A compact optical scanning system comprises a portable enclosure structure having a cover portion which includes a glass enclosed aperture over which a UPC label attached to a purchased merchandise item is moved. Mounted within the enclosure is a laser whose output coherent light beam is reflected along a path extending in a direction parallel to the cover portion by mirrors and a bifocal lens member mounted on a shelf extending between opposite sidewalls of enclosure. One of the mirrors mounted on the shelf reflects the laser beam in a downward direction at a rotating multifaceted mirrored member mounted on and directly beneath the shelf and the bifocal lens. The rotating mirrored spinner directs the laser beam at a plurality of pattern mirrors which redirects the received laser beam towards the aperture, forming a scan pattern thereat for scanning the UPC label.

Abstract: An optical beam scanner includes a light source, a deviation unit for deviating a beam from the light source and emitting a scanning beam, a compensation unit for compensating a vertical inclination of the deviation unit and having a first optical element for deforming the scanning beam into a vertically longitudinal oval shape and a second optical element for reforming the oval beam into a round shape and converging the scanning beam on a scanning surface. A detection unit detects the scanning beam and is disposed between the deviation unit and the second optical element.

Abstract: Apparatus for comparing a test surface 23 with a reference surface 8 comprising detector means 16.17, a test channel TC for receiving radiation from the test surface 23 and a reference channel RC for receiving radiation from the reference surface 8. A selector means 12 is provided to pass radiation from the test channel means TC and the reference channel means RC to the detector means. Varying means 5 is provided to vary the radiation passed along the test channel TC and reference channel RC. Cycle means is provided to cycle the selector means 12 between a first state in which more radiation from the test channel TC than the reference channel RC is passed to the detector means and vice versa. Control means is provided to control the radiation varying means 5 to provide a zero or minimum variation of radiation received by the detector means as the selector means 12 is cycled.

Abstract: An optical device for discriminating threaded workpiece by the handedness by their screw thread profiles. The device presents a pair of light beams which pass generally tangent to the workpiece at angularly displaced positions. The light beams are inclined to follow the helix direction of a given handedness of a workpiece. Upon axial advancement of a workpiece through the device, a chopped output from the photodetectors indicates that the handedness of the threads matches the inclination of the light beams. The oppositely threaded workpiece, however, provides a generally constant DC output. With appropriate signal processing electronics, an automatic system for discriminating workpieces by thread handedness is provided.