Abstract: A method of measuring light levels, particularly the measurement of exterior light levels in the zone of approach to a tunnel in which vehicles are moving, and from which exterior light levels the minimum light level to be programed inside the tunnel can be calculated, by means of a photo-sensitive cell installed in a recessed tube in order to sense light levels contained within a cone defined by the center of the cell, which constitutes the apex of the cone, and by at least the open end of the tube. The method includes limiting the quantity of light rays entering into tube via the cone, and a device is provided for implementing the method.

Abstract: The linearity of a photoresistive device at varying levels of radiant signal is improved by masking the sensitive area of the photoresistive device so that only a portion of the sensitive area is illuminated. The masking prevents exposure of the entire surface area of the cell, which increases the dynamic range, allowing a more linear, small signal sensitivity over wide variations in brightness.

Abstract: In the photometer arrangement comprising a light source, lens system with beam splitter, measurement cell, scattered light trap and photodetector, said parts being arranged in this sequence, the scattered light trap comprises a honeycomb. The ratio between the free cross-section of its individual channels and the length thereof is from 1:40 to 1:300.

Abstract: A pyroelectric detector is provided to measure the energy of pulsed light. To measure the power of continuous wave light (CW light), the pyroelectric detector is releasably attached to optical sampling apparatus which divides the CW light into pulsed light. Means are included to inform processor circuitry in the read-out electronics that the detector is attached to the optical chopper. The processor circuitry then calculates the power of the CW light given the energy of the pulsed light by the pyroelectric detector and the exposure time which is fixed by a crystal clock.

Abstract: Each of three or more telescopic filters in pairs of filters and detectors therefor has very narrow passband lines centered about laser wavelengths and nearby guardbands. As defined, a passband is any wavelength region of the spectrum permitted by a system to pass through to a detector, and a guardband is a spectral region near but not including the laser lines of interest. Each laser wavelength is simultaneously detected in exactly two detectors. Associated with each wavelength is a guardband near that wavelength, which is used to detect and reject broader band radiation. False alarms are made rare by proper parameter selection.

Abstract: A product discrimination system using a lens assembly for projecting an image of the product unit toward a randomized fiber optic cable. The end of the fiber optic cable is constructed in a rectangular section such that a long thin section of the product unit is viewed at any given time. The cable discharges the light at a lens and filter arrangement such that the emitted light may be divided into portions and filtered for measurement by photodiodes of specific and different wavelengths. Through a comparison of the wavelengths to a standard, attributes of the product unit can be determined. A method for distinguishing between adjacent product units which are not separated one from the other employs sensing a plurality of decreasing widths followed by a plurality of increasing widths to establish a product end therebetween. Off-loading elements on the conveyor are assigned by location of the product units.

Abstract: A technique for the simultaneous measurement, in real time, of the changes in mode size, pulse length, and power of a wavetrain of laser pulses delivered by mode-locked or other pulsed laser systems contemplates directing respective portions of the beam along each of three beam paths. The beam portions along the first and second beam paths are subjected to respective, and different, degrees of focusing, and then passed through respective non-linear elements which generate radiation at the second harmonic. The first harmonic components are removed, and the second harmonic components are passed to respective first and second detectors which generate signals representative of the total second harmonic energy along each of the first and second beam paths. The beam portion along the third beam path is passed to a detector which generates a signal representative of the total energy in the beam pulse. The three signals are combined to give values proportional to peak power, pulse length, and mode size.

Abstract: Photodetectors having low reflectivity triangular groove, surface relief gratings on homogenous material or one layer of a heterostructure. Preferably, the photodetector is a PIN photodiode in which the p-type layer is triangularly grooved. The surface relief gratings have an optical repeat distance greater than the wavelength of light which impinges on the photodetector surface. Thus, zero order backward diffracted waves are not coupled into optical reflections which would thereby decrease the optical return loss (ORL). Furthermore, the surface relief gratings have minimum side-wall angles to limit reflection at the heterostructure interfaces from contributing to the ORL. The side-angles of the gratings are chosen to ensure that the angle of the higher order backward diffracted wave is greater than the capture angle of an optical receiver into which the photodetector is incorporated. The free-space depth of the grooves is a half-wavelength of the light impinging on the photodetector.

Abstract: A detector is disclosed which includes an elliptical hollow mirror and a tube having a reflecting inner surface for conducting the light emitted by a specimen under investigation in a scanning electron microscope. A vacuum window is seated at the outer end portion of the tube directly ahead of a receiver.

Abstract: A photometer tube for microscopes is provided with a device by means of which the measurement field diaphragm of the photometer is superimposed on the intermediate image of the object in the binocular tube. For the reflecting-back of the measurement field diaphragm, which is illuminated from the rear, into the binocular tube, the residual reflection of an uncoated glass-air interface in the ray path between the objective and the beam divider of the microscope is utilized. This surface may be one of the surfaces of the tube lens systems of the microscope.

Abstract: A microscope tube contains prisms mounted on a prism carriage switchable between a position for visual observation of a specimen and a position for photometry or photography of the specimen. A diaphragm (6) mounted on and movable with the carriage has a blocking position impeding entrance of light through the eyepiece window of the tube, and an ineffective or non-blocking position which does not impede entrance of such light. A manually operable handle in the form of a knob (9) mounted externally of the tube controls mechanical linkage parts (8, 10, 11) for shifting the diaphragm from its blocking position to its non-blocking position when the carriage is in the photometry or photography position, in case the user may wish to make a visual inspection of the specimen at that time.

Abstract: A radiation spot position sensor utilizing a diffuse material upon which a spot of radiation impinges and diffuses from that point outwardly along the material to the two ends thereof in a proportion indicative of the linear position of the spot along the sensor so as to be detected by radiation sensing devices located at the ends to produce and output that can be used to determine the linear position of the spot.

Abstract: Disclosed is an entrance system having an image angle of 180.degree. suite for a radiation detector for detecting differing wavelengths of sunlight, comprising a hemispherical shell of light transmitting material; a tube of light transmitting material extending coaxially from the hemispherical shell; a granulated light scattering medium containing inside the hemispherical shell; and a stepped body of light transmitting material inserted into the tube, the stepped body having an end which terminates in at least three steps and which abuts against the granulated medium and seals the medium in the hemispherical shell.

Abstract: A photometer tube for a microscope contains several switchable reflectors (5, 11). By the appropriate use of these, the ray path (c) for the back-illuminated measuring field stop (7) is reflected out of the photometry ray path (b) and is conducted to a second image inlet (32) of a beam splitter prism or prism slide. Various switchable elements (mirrors 5 and 11; stop 4; prism 2/22) in the tube are electrically driven and are centrally actuated from a control unit.

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 photometer is providing including light detecting means for detecting incident light and generating electric signals in response thereto as a measure of the incident light thereon, and optical means for guiding light to the light detecting means from a standard light source in a calibration mode and from an object, a photometric quantity of which is to be measured, in a measurement mode.

Abstract: A two-dimensional knife edge mask comprised of an array of spaced periodic rectangular opaque regions (e.g., a chrome grating pattern layer deposited on one surface of a slide) separated by transparent different given spacing stripes between adjacent rectangular regions in each of the two orthogonal dimensions thereof, is linearly moved at a fixed velocity across an incident light spot, the direction of movement being oblique to the orthogonal dimensions of the rectangular regions and the distance of movement being sufficient to traverse at least one entire spacing strips in each of the two orthogonal dimensions. A photocell (which may be secured to the other side of the slide) senses the occulted light.

Abstract: The fundamental-mode field radius `w` is a key parameter in characterizing optical fibers. `w` is a function of P, .theta. and .lambda. where P is the far-field power passing through a circular aperture subtending a solid angle of 2.theta. at the fiber end face and .lambda. is the center wavelength of transmitted length. `w` is derived by moving a fixed diameter aperture along an axis extending between the test fiber end surface and a photodetector so as effectively to vary .theta.. At each location the power P incident on the photodetector and the corresponding acceptance angle .theta. are measured. A microprocesor is programmed to compute from the range of measured values of .theta. and P, the value of mode field radius for a particular transmission wavelength .lambda..

Abstract: An image information detecting device for detecting the density for printing is required to cover a wide dynamic range corresponding to the density scope of the original film as well as to cover the fluctuation in values caused by different lamps and filters used in the photometric system. It is also important in photographic printing process to detect the density information on a relatively wide area of a frame of a negative film or the like in order to determine exposure or correction amount. The present invention enables the use of a storage-type light receiving element over a wide dynamic range as well as segmentation of picture images of a film of a wide scope into a large number of picture elements for detection.

Abstract: This invention provides a device for measuring light incident on an optical system. This device includes an optical system defining an optical path, a beam splitter and a photo detector. The beam splitter has a relief type diffraction lattice having a plurality of semireflecting surfaces periodically arranged and included in a transparent body. The diffraction lattice is arranged to split a portion of the incident light by its effect of reflection/diffraction and its beam splitting efficiency having a predetermined distribution within the lattice area. The diffracted light from the diffraction lattice is directed to the photo detector.

Abstract: The invention contemplates a photometer tube having a rotatably mounted slit-diaphragm insert, with provision for scanning a specimen object through the slit, in the direction perpendicular to the instantaneous longitudinal orientation of the slit. In a first embodiment, the rotatable slit is coupled with an angle transmitter which supplies a control signal for scanning by a motor-driven X-Y specimen stage. In a second embodiment, the diaphragm holder itself is mounted on a carrier, for lineal displacement on the carrier in the direction perpendicular to the direction of the slit, and the carrier is rotatable to permit slit orientation with respect to a pattern of interest in an observed specimen.

Abstract: A method and apparatus for illuminating a surface to provide a desired light intensity. The light intensity at discrete points along the illuminated surface is measured through a light transparent material, and opaque materials are applied to the transparent material to block out some of the light and thereby produce a light filter such that the desired intensity at each of the discrete points along the surface is obtained. An oscilliscope, or alternatively, a computer display to indicate light intensity are used.

Abstract: An apparatus for measuring the scalar irradiance of a given vicinity produced by all sources over a given angular range. The apparatus includes a planar array of convex spherical surfaces, a detector oriented toward the array, and a shielding plate having holes which abut and secure the convex spherical surfaces.

Abstract: A system for measuring incident light includes: an optical system defining an optical path; a photodetector; and a plurality of beam splitters, with each beamsplitter having a different, predetermined area and adapted to be disposed in the optical path with, at any one time, only one beam splitter in the optical path; and means for measuring the light received by the photodetector.

Abstract: A plurality of photodetectors are arranged to receive light from different parts of a photographic subject matter. The outputs of the photodetectors are weighted according to the position of the photodetectors. The weighted outputs are summed up and used as image brightness information. The weighting can be made by varying the size of the photodetectors or changing a covering area of a mask provided to cover the photodetectors.

Abstract: A device for radiation detection over a broad field, especially for laser radiation detection. The device comprises a photodetector associated with an optical receiver formed by two diaphragms which delimit the field, and an optical diffusing element. In a preferred embodiment, a diffusing paint is deposited on a flat surface of a mechanical part, and a mirror for reflecting the diffused radiation makes it possible to mount at the rear end of the device either the photodetector or an optical fiber terminal to which the photodetector is remotely coupled.

Abstract: A photometer having asymmetrical apertures and with compensation for direction of incidence includes a photodetector, a mask having asymmetrical apertures and arranged before the photodetector and a compensation prism arranged either before or after the mask. The photometer is adapted to compensate for the difference in quantity of light incident on the photodetector caused by the mask depending on the difference in the direction of incidence of the light.

Abstract: With an exposure meter usable in both reflected light mode and incident light mode, the exposure meter is capable of displaying a value measured in reflected light mode with a reflected light mode attachment mounted on the exposure meter, and a value measured in incident light mode with an incident light mode attachment mounted thereon.

Abstract: Method and apparatus for automatically controlling exposure of a photographic film by evaluating selected spectral scene light frequencies during certain ambient light portions of an exposure interval and evaluating scene light frequencies exclusive of visible frequencies during other portions of the interval.

Abstract: Method and apparatus are disclosed which direct a preliminary pulse of radiation from a selectively energizable light source toward a subject, and a device for evaluating the amplitude of the reflected pulse of radiation therefrom so as to determine a weighted range signal as a function of the amplitude of generally non-visible radiation frequencies selected for reducing the non-uniformity in reflectivity values of reflected visible radiation in the scene, which weighted range signal includes a reflectivity factor and a range factor. The reflectivity factor, which detracts from the range factor for focusing, significantly enhances exposure control under certain scene lighting conditions.

Abstract: Method and apparatus usable for automatically controlling exposure of a photographic film by evaluating selected spectral scene light frequencies during certain ambient light portions of an exposure interval and evaluating additional spectral frequencies during a flash portion of the interval.

Abstract: Apparatus for automatically varying positioning of an infrared filter relative to a light sensing photocell of an exposure control system having scanning type shutter blades provided with cooperating pairs of primary and secondary apertures, which are displaced between first and second positions to respectively control the passage of light to a film plane and to the photocell, includes an infrared filter cooperating with at least one secondary aperture for blocking transmission of infrared to the photocell when the apertures are positioned for high ambient light conditions and for allowing passage of infrared to the photocell when positioned for low ambient light conditions where flash illumination provides a greater contribution to the exposure.

Abstract: Method and apparatus using shutter blade and photocell lens arrangement for automatically controlling exposure of a photographic film by evaluating selected spectral scene light frequencies during certain ambient light portions of an exposure interval and evaluating additional spectral frequencies during a flash portion of the interval.

Abstract: A photoelectric radiometer structured to generate an output signal that can be used to predict an exposure value for a photographic scene as based on the magnitude of the radiometer output signal. The radiometer is provided with a preferred relative spectral sensitivity in the visible and near infrared regions of the spectrum to minimize exposure errors which otherwise can occur with certain types of high contrast scenes which contain objects that have widely different visible reflectivities. A positive lens collects radiation from a scene and directs it onto the surface of a silicon photodiode which in turn provides the output signal. The spectral sensitivity of the photodiode is suitably altered, e.g., with a filter, to provide the radiometer preferred relative spectral sensitivity.

Abstract: A scanning device adapted to be associated with a radiant energy measuring meter such as a luminance photometer to provide precision linear or angular scanning across an area of an object or a subject being measured without relative movement of the meter or subject. A scanning device which includes an optical assembly having an objective lens and a prism movable as a unit along or about the optical axis portion of light beams reflected or folded by and between the prisms whereby light received by the photometer is on the optical axis of the photometer regardless of the position of the movable optical assembly on the folded optical axis portion. Means are provided for moving the movable optical assembly linearly with respect to the optical axis portion for linear transverse scanning of a subject area or rotatively about said optical axis portion for angular scanning of a subject area.

Abstract: An apparatus for measuring the intensity of light reflected from a scene along an optical path includes a photoelectric cell, an optical lens and a light-attenuating device that has a gradation of opacity along one dimension that extends generally transversely to the optical path. The device may be moved transversely of the optical path to vary the average amount of light impinging upon the cell. The cell has a gradation of sensitivity to light along a dimension that extends generally transversely of the optical path. The sensitivity varies along the cell dimension and the cell is so disposed so as to be correspondingly more sensitive to light that has passed through more opaque portions of the light attenuating device and less sensitive to light that has passed through less opaque portions of the light attenuating device. The apparatus may be incorporated in a photographic camera and may be coupled to the camera's exposure control mechanism.

Abstract: A complete system for detecting and metering solar energy and recording the total integrated energy or power levels over a desired period of time.

Abstract: The meter senses flashes of illumination, it converts the illumination to an electrical current whose magnitude is proportional to the intensity of the illumination; it integrates the current over a period of time corresponding to a selected shutter speed by charging a capacitor; it discharges the capacitor and measures the time required to do so; it converts the time required to discharge the capacitor into a corresponding signal representative of an appropriate camera aperture setting for a preselected film sensitivity and shutter speed via a microprocessor and a stored data program; and then displays the camera aperture setting on a multi-segment display. This process is repeated with each new flash of illumination automatically. The meter also measures multiple flashes and displays an accumulated camera aperture setting as well as the number of flashes needed to accumulate that setting.

Abstract: A scanning accessory for a microscope/photometer, where the photometer system is mounted to or inside an intermediate tube of the microscope and the intermediate tube is provided near or at the one end of its lower side with a coupling system for mounting to the stand and at the opposite side with a coupling system for mounting the ocular, the photometer being inserted into the intermediate tube's beam by means of a beam splitter, a subsequent triple mirror and an ocular. The scanning accessory preferably periodically changes the relative position of the transmitted beam (4a) and of the image (76a) or (76b) of the measuring stop (42) with respect to the microscope image (72) and is located between the photometer system (41-46) and the beam splitter (22) mounted inside the intermediate tube (2) of the microscope for the purpose of enlarging the application possibilities of the microscope/photometer.

Abstract: A light smoothing device for rendering a non uniform distribution of light more uniform especially suited for use in line scanning in combination with a light conducting rod which transmits light incident on its surface to its end faces for subsequent detection. The smoothing device has an optical passage with a reflecting interior surface an inlet to the passage and a detector at the other end of the passage. The passage ensures at least part of the light entering the inlet is reflected prior to incidence on the detector.A number of forms of optical passage are disclosed having various reflecting segments of convex, plain or concave curvature.

Abstract: An apparatus for measuring scalar irradiance or the incident flux of radiant energy from a 4.pi. solid angle about a point. The present invention relates to an apparatus which comprises a solid spherical radiant energy collector, a radiant energy detector which converts radiant energy into electrical signal, a light conductor which transmits a portion of the radiant energy within the spherical collector to the detector, a means for conditioning the electrical signal such that the electrical signal responds to the intensity of the incident flux, and a means for displaying the conditioned signal. The apparatus further includes a spectral shaping assembly located intermediate the detector and the light conductor whereby the spectral characteristics of the radiant energy are adjusted to compensate for apparatus response in the desired spectral region.

Abstract: A system and apparatus for providing a measure of ESI (equivalent sphere illumination) as a function of Lb (background luminance) and Lt (task luminance) and in which a pair of envelopes are provided each having a varying transmittance such that one envelope can provide an indication of the term (Lb-Lt) and the other an indication of Lb whereby ESI can be determined.

Abstract: A protection device for an electro-optical detector used in systems for making far field diagnostic measurements of a high energy laser beam comprises a solid silicon cone having a truncated apex which functions as the pin hole aperture for the detector. The large end of the cone has a surface defined by the radius drawn from the cone axis at the truncation. This surface is coated with a reflective attenuation layer which reflects a high percentage of the energy of the incident laser beam entering the pinhole aperture thereby minimizing the absorption of the beam by the cone. The high index of refraction of the solid silicon cone permits large off-axis angles of the laser beam to be directed onto the detector resultingly increasing the field of view of a system using a given detector. The increased field of view allows a closer spacing of a plurality of detectors in the system ensuring a high spatial resolution of the laser beam for a desired field of view.

Abstract: A hollowed frusto-conical member has its base mounted adjacent the output of a laser. The apex portion extends outwardly from the laser output. The design of the member causes laser light to reflect many times as it travels from the base at a large aperture of the member down to the apex or focal point. The member may be made from light absorbing plastic material which absorbs most of the laser light and reflects only an infinitesimal portion.

Abstract: A defocused unicell photometer of the type having a positive lens element is provided with at least one diffusion zone on a portion of the lens element surface to change the directional response characteristic of the photometer in a select manner without increasing the extreme field of view of the photometer.

Abstract: A defocused unicell photometer of the type having a positive lens element is provided with at least one aspheric zone on a portion of the lens element surface to change the directional response characteristic of the photometer in a select manner without increasing the extreme field of view of the photometer.

Abstract: A unicell photometer of the photoelectric type having a single tilted plano-convex lens with a series of spaced prisms integrated with the plano surface to provide the photometer with different horizontal and vertical specific acceptance angles while simultaneously aiming the field of view of the photometer below the horizontal plane.

Abstract: A unicell radiation measuring device having a single electrical output signal that can be correlated with film sensitometric characteristics and scene object luminance patterns to either predict photographic exposures directly, or alternatively, used as an input function for controlling a camera exposure control system. The device consists of an optical system having a single optical element for collecting and directing radiation from a scene onto the surface of a photoelectric transducer element having a spectral sensitivity substantially identical to the photopic visual response curve of the standard photometric observer according to the CIE thereby qualifying it as a photometer. The optical element consists of a central circular planar portion of uniform thickness surrounded by an annular positive lens portion having radially decreasing thickness. Both portions are integrally molded to provide the optical element with a unitary construction that is rotationally symmetric.

Abstract: A system for fully characterizing monochromatic radiation incident on the stem. The system computes the azimuth and elevation of the point of origin, optical frequency, pulse width, power level and pulse repetition frequency of the source.

Abstract: An exposure apparatus for production of ICs of the type that includes a stage on which is placed a semiconductor wafer to be exposed by illumination light projecting means, and means for two-dimensionally moving the stage within a plane intersecting the illumination light at substantially right angles. The improvement comprises illumination detection means provided with a photo reception surface, and means for mounting the illumination detection means on the stage in such a manner that the photo reception surface and the surface of the semiconductor wafer on the stage to be exposed are at substantially equal height relative to the stage.