Abstract: A photometric test system for LED luminaires. The system uses photodetective panels to detect and measure light. By placing an optical absorber layer with low reflectivity and low transmissivity over the photodetective panels, a detection surface which is also an absorber is achieved. This absorber reduces reflection of incident light from the device under test (DUT), and light reflected from the photodetective panels. A pinhole array can be conveniently used for this purpose. This enables the measurement area of the system to be essentially no larger than the emitting area of the DUT. A diffuser positioned between the absorber layer and the photodetective panels increases the accuracy of the system. Simulations and experimental results show that this system can measure total flux with an uncertainty of 4.3%. The demonstrated system is used in 2? geometry. The system measures total flux, color parameters (such as CCT, CRI, chromaticity) and flicker.

Abstract: A power measuring sensor for an optical beam which utilizes the temperature difference across a thin layer of heat insulating material, generated by the axial flow of the absorbed beam, from an absorber layer on which the beam impinges, to a cooled heat sink which dissipates the heat after passage through the sensor. The axial heat flow is measured by means of a continuous matrix of adjacent thermocouple junctions over the heat flow region of the sensor disc, with the thermal insulating layer, which generates the temperature drop, having thicker and thinner regions at alternate junctions. The junctions on the thicker regions of the insulator thus become the hot junctions, and those on the thinner regions of the insulating layer become the cold junctions, and the sum of the voltages generated by the thermocouples is proportional to the flow of heat, and thus to the incident optical power.

Abstract: A laser power meter incorporating an absorber disc with a peripheral thermopile ring, either continuous or segmented, and an additional temperature detection element in the central portion, that enables measurement of beam size. This detection element can be a thermopile element, generally a ring of smaller diameter than the peripheral thermopile used, and located closer to the center of the absorber disc. With this arrangement the beam size can be measured, in addition to measurements of the power and the position of the beam. Alternatively, this centralized detection element can be a single thermocouple junction located at the center of the disc, which acts as the hot junction of a thermocouple pair. The second or cold junction is effectively located on the disc close to the peripheral thermopile. Alternatively, two temperature measuring elements can be used, one at the disc center and one at the periphery.

Abstract: A power measuring sensor for an optical beam which utilizes the temperature difference across a thin layer of heat insulating material, generated by the axial flow of the absorbed beam, from an absorber layer on which the beam impinges, to a cooled heat sink which dissipates the heat after passage through the sensor. The axial heat flow is measured by means of a continuous matrix of adjacent thermocouple junctions over the heat flow region of the sensor disc, with the thermal insulating layer, which generates the temperature drop, having thicker and thinner regions at alternate junctions. The junctions on the thicker regions of the insulator thus become the hot junctions, and those on the thinner regions of the insulating layer become the cold junctions, and the sum of the voltages generated by the thermocouples is proportional to the flow of heat, and thus to the incident optical power.

Abstract: A laser power meter incorporating an absorber disc with a peripheral thermopile ring, either continuous or segmented, and an additional temperature detection element in the central portion, that enables measurement of beam size. This detection element can be a thermopile element, generally a ring of smaller diameter than the peripheral thermopile used, and located closer to the center of the absorber disc. With this arrangement the beam size can be measured, in addition to measurements of the power and the position of the beam. Alternatively, this centralized detection element can be a single thermocouple junction located at the center of the disc, which acts as the hot junction of a thermocouple pair. The second or cold junction is effectively located on the disc close to the peripheral thermopile. Alternatively, two temperature measuring elements can be used, one at the disc center and one at the periphery.

Abstract: A night vision system, suitable for vehicular use, including an infra-red detector mounted on a vehicle, a display mounted on the vehicle, a single-element lens mounted upstream of the infra-red detector so as to direct light from a scene onto the infra-red detector, and circuitry operative to receive a detector output from the infra-red detector and to provide an image output based on the detector output to the display. The system is suitable for applications other than vehicular use, where a comparatively narrow field of view is to be imaged.

Abstract: An optical power meter using a thermal detector, with improved response time, in which a fast response sensor is mounted close to the thermal detector, in such a location that it senses a part of the incident beam to be measured. The output signal of the fast response sensor, and the output signal of the thermal detector are electronically combined, such that response characteristics of the fast response sensor are impressed on the output of the thermal detector, thus providing a power meter combining the power handling ability and the accuracy of the thermal detector with a response characteristic of the fast response sensor. This method of combining fast and slow response sensors is also applicable to other measurements, whether physical, chemical or biological, such as those of flow, velocity, temperature, pressure, electrical, electronic, magnetic, thermal, optical, radiative, dimensional or acoustic properties of a material or article.

Abstract: A dispersive spectrometer whose dispersive element is aligned such that the direction of dispersion is essentially perpendicular to the collimating plane, which is the plane of the input beam path between the centers of the input slit, the collimating mirror and the dispersive element. As a result of this construction, the lateral spread over which the beam path traverses is reduced, since use is also made of the direction perpendicular to the input beam path plane for the dispersive spread of the beam, and the spectrometer is thus of compact construction.