Abstract: A device for detecting road surface condition in front of a running car by radiating a directional beam or beams onto a point or points on the road surface at predetermined distance or distances in front of the car body and receiving the reflected beam or beams from said point or points, and determining the road surface condition based on the measurement of the distance or distances.

Abstract: An apparatus for measuring particles contained in a sample liquid has a cylindrical cell having an incident light transmitting portion, a transmitted light transmitting portion diametrically aligned with the incident light transmitting portion, and a light transmitting portion at an angle to the diameter between the incident light transmitting portion and the transmitted light transmitting portion. An inlet at one end of the cell admits sheath flow liquid having the same index of refraction as the sample liquid, and an outlet is provided at the other end of the cell.

Abstract: A method and an apparatus for optical strain measurement are disclosed. Prior to the deformation or loading of the object to be tested, the latter is provided with a thin transparent film which adheres well to the object and has a thickness between 3 and 20 .mu.m. After the deformation or during loading, the wavelength-dependent intensity course developed because of the interference of the portion of the beam of light reflected and superimposed at the boundary surfaces of the transparent film is measured and evaluated by a computer.

Abstract: An atmospheric optical calibration system is provided to compare actual atmospheric optical conditions to standard atmospheric optical conditions on the basis of aerosol optical depth, relative air mass, and diffuse horizontal skylight to global horizontal photon flux ratio. An indicator can show the extent to which the actual conditions vary from standard conditions. Aerosol scattering and absorption properties, diffuse horizontal skylight to global horizontal photon flux ratio, and precipitable water vapor determined on a real-time basis for optical and pressure measurements are also used to generate a computer spectral model and for correcting actual performance response of a photovoltaic device to standard atmospheric optical condition response on a real-time basis as the device is being tested in actual outdoor conditions.

Abstract: In a photoelectric type measuring method and device wherein a workpiece to be measured is scanned by parallel scanning ray beams for scanning in one direction, aforesaid ray beams after the scanning are received by light receiving elements and a time length of a dark portion or a bright portion generated due to the obstruction of a portion of the ray beams by workpiece to be measured in response to output signals from the light receiving elements is detected so as to obtain the dimension in the scanning direction of the workpiece to be measured, the aforesaid ray beams are split into ray beams polarized in directions different from each other, the workpiece to be measured is scanned in such a condition that the two ray beams are relatively shifted so that the two ray beam may be partially overlapped in the scanning directions thereof and light receiving signals corresponding to the two ray beams after the scanning are processed to detect and edge of the workpiece to be measured.

Abstract: In a photoelectric measuring arrangement two grids operating as a scale and a scanning plate are built up of several component phase grids which define periodic graduations having differing grid constants. The periodic signals of differing periodicity arising through diffraction are optically or electrically summed.

Abstract: A method and an arrangement for aligning relative to each other a mask pattern (C) and a substrate (W) which are both provided with two alignment marks wherein by using two separate alignment systems (AS.sub.1, AS.sub.2) which are each associated with one mask mark (M.sub.1, M.sub.2) and which are each used for aligning the substrate marks (P.sub.1, P.sub.2) relative to said mask marks the substrate (W) and the mask (M) can be aligned accurately without referring to the frame of the exposure apparatus and in addition it is possible to detect magnification errors.

Abstract: A device for measuring an object includes a laser beam, a translator for moving the object with respect to the beam, an object reference plane which is the plane perpendicular to the beam that is first entered by the object, a lens system for imaging a light pattern formed in a second plane onto a first plane, wherein the second plane is adjacent to the object reference plane, and the light pattern includes a diffraction pattern caused by interaction of the beam and the object, a slit interposed at the first plane for limiting the extent of the beam that passes through the first plane, and a photodetector that emits a signal representative of the light received behind the slit for detecting the portion of the beam that passes through this slit. The slit is sufficiently small so as to enable resolution of the diffraction pattern by the photodetector. The device further includes a circuit for calculating a dimension of the object in response to the signal emitted by the photodetector.

Abstract: An optical spot scanning system for use in three dimensional measurement and inspection of an object surface wherein a deflector means is placed in the path of the projection axis of the spot projector to deflect the portion of same between the deflector and the object surface, thereby moving the spot to various positions on the object surface, and wherein the deflector means is also positioned in the path of the optical axis of the system sensing means to deflect the portion of same between the sensing means and the object surface by the same degree as the portion of the projection axis is deflected, thereby ensuring the axes portions which are aligned to be coplanar remain coplanar, and that the image of the spot on the object surface will be properly conveyed to the linear sensor array in the sensing means.

Abstract: The invention concerns a procedure for measuring the thickness of a film-like or sheet-like web. In the procedure, measuring heads located on both sides of the web and detectors provided in these are employed to measure the distances of the measuring heads from the respective surface of the web. Moreover, the distance from each other of the measuring heads is measured and from the three results of measurement thus obtained, the thickness of the web is calculated. The invention furthermore concerns a measuring means for implementing the procedure, this means comprising measuring heads located on both sides of the web, at a distance from the web, these measuring heads being provided with detectors for measuring the distance of each measuring head from the web surface on the respective side and with a detector for measuring the distance between the measuring heads.

Abstract: In the surface inspection apparatus disclosed herein, an elongate array of electro-optical shutters is interposed between a laser beam which scans across the surface to be inspected and a photodetector system which collects light scattered from the surface along the scan line. The shutters are operated in a shifting pattern in synchronism with the scanning means thereby to block unwanted regular signal components.

Abstract: An instrument for measuring radiation including a probe for collecting light. The probe includes a diffusive reflective surface at the forward end of the probe and an aperture block containing a pair of apertures to direct light reflected from the reflector to an optical waveguide and then to a light sensor and display unit.

Abstract: A device is described for detecting a magnification error in an optical imaging system comprising a lens system (L.sub.1, L.sub.2) which is telecentric at one side. Two gratings (RG.sub.1, RG.sub.2) arranged in the object plane (MA) are imaged onto two gratings (WG.sub.1, WG.sub.2) arranged in the image plane (W; WT) and the radiation beams (b.sub.1, b.sub.2) by means of which these images are formed are incident on two radiation-sensitive detection systems (D.sub.1, D.sub.2) which supply periodic signals (S.sub.1, S.sub.2). By phase comparison of these signals a magnification error (S.sub.ME) and, if desired, a focussing error can be measured very accurately.

Abstract: The duration of a very short semiconductor laser pulse, such as that ranging from a fraction to hundreds to picoseconds, can be measured utilizing the internally generated second harmonic emission of the laser. A laser diode is driven so that light emitted therefrom can pass through a beam splitter and be reflected by the beam-splitter into a photomultiplier and into a detector, respectively. Signals received therefrom relate to the conversion efficiency of the second harmonic emission generated by the picosecond pulses and of either continuous wave emission or pulse emission whose durations can be accurately measured by photodetectors. Apparatus includes a photodiode for measuring the fundamental laser power, a photomultiplier for measuring the second harmonic power, and appropriate filters. Ammeters coupled to the photodiode and photomultiplier measure the appropriate current. The ratio of the current can be determined by a ratio circuit or a computer.

Abstract: An equipment for optically measuring the height of step according to the present invention is characterized in that a linearly polarized laser beam from a laser source is guided onto the side of an object through an optical fiber transferring said beam in the state that the plane of polarization thereof is maintained, the beam emitted from the optical fiber is applied onto the spots in proximity to each other on the surface of the object through the intermediary of an optical system separating said beam into two component beams having planes of polarization perpendicular to each other, the beams reflected from the surface of the object are made to go back through the aforesaid optical system so that two optical paths overlap each other, and are passed in the reverse direction through the aforesaid optical fiber and guided onto the side of the laser source, the optical power of the component parallel to the plane of polarization of the incident beam and the component perpendicular thereto out of the reflected

Abstract: A device for characterizing the formation of a sheet material is described. The device comprises a basis weight sensor for measuring the basis weight of the sheet material as the material moves through the sensor and signal processing circuitry which receives a signal from the basis weight sensor indicative of the measured basis weight. The basis weight sensor includes a light source for directing a beam of light at the moving sheet and a light detector which detects the beam after it passes through the sheet. This detector produces a signal indicative of the intensity of the detected beam and transmits the signal to the signal processing circuitry. To calibrate the signal processing circuitry, a rotatable opaque wheel having a plurality of slots is positioned in the path of the light beam. The rotating wheel alternately blocks the light beam and allows the beam to pass through the slots to the detector.

Abstract: A method of aligning an optical signal source and a waveguide which comprises; directing the signal into the waveguide, monitoring the intensity of the signal backscattered along the waveguide, and altering the relative positions of source and waveguide in response to said intensity.

Abstract: The present invention relates to an optical system of a radiation thermometer in which the measuring optical system and the finder optical system can be focused. The central portion of the sub-mirror in Cassegrainian type optical system is used as a finder lens of the finder optical system. The third mirror is located between the main and sub-mirrors in order to reflect the light passed through the central portion of the sub-mirror. The light reflected on the third mirror is used for finder observation.

Abstract: An apparatus for optical measurement of the shape of oblong objects. The apparatus having a measurement base for an object to be measured, a camera, and image processing means connected to the camera for processing the images information received from the camera into control data. A mirror is positioned at a distance from the measurement base for reflecting the image of the object located on the measurement base to the optics of the camera. The reflecting face of the mirror has a curvedness that is different in the longitudinal direction the object as compared with the width direction so that the image of the object, reflected to the optics of the camera is reduced in the longitudinal direction as compared with the width direction.

Abstract: An identification method and identification kit are based upon making up groups of microsized particles normally invisible to the naked eye with each particle in each group being of a selected uniform size, shape and color. Coded identification is established by transferring a population of particles from a selected number of the groups to the item to be identified and then confirming such identification by examining the marked item under high magnification with a light microscope.