The present application discloses a method of using a LED-based solar simulator light source having at least one LED array formed by multiple LED groups of LED assemblies, at least one field flattening device, at least one diffractive element, and at least one optical element configured to condition the broad spectrum light source output signal and direct the light source output signal to a work surface.

A solar simulator filter that includes a flexible substrate and one or more layers of oxide materials, e.g. fluorine-doped tin oxide and indium-doped tin oxide, wherein a thickness of said layers is no more than 500 nm, and wherein the solar simulator filter generates a spectral output that closely matches a solar irradiance spectrum. Various embodiments of the solar simulator filter and a method of fabricating thereof is described.

An optical system (2A) is disclosed for receiving and collimating light, wherein the optical system (2A) comprises a collimation unit (200) comprising at least one parabolic interface (220, 230) that defines an inlet opening (212) and an outlet opening (214), wherein the at least one parabolic interface (220, 230) is configured to reflect light entering through the inlet opening (212) through the outlet opening (214) and limit the angular spread of the light to an acceptance angle (?.sub.CPC) associated with the at least one parabolic interface (220, 230); and a homogenization unit (300) for homogenizing the light emerging from the collimation unit (200), the homogenization unit (300) comprising a lens array with pairs of a first lens and a second lens, wherein the lens array is configured such that light from the outlet opening (214) collected by a first lens illuminates the respective second lens to provide for a continuously emitting output aperture.

An integrated cap for retrofitting an existing light fixture can include an integrated cap housing that is configured to be disposed atop a pole that supports the existing light fixture, where the integrated cap housing includes a communication module and a transceiver. The integrated cap can also include a first coupling feature disposed at a bottom end of the integrated cap housing, where the first coupling feature is configured to couple to a first component of the existing light fixture to provide electrical signals to the communication module and the transceiver, where the communication module and the transceiver communicate with a second component external to the existing light fixture.

A system and method provide fail-safe operation of a lighting system. A lighting level detector is used to obtain a baseline lighting level for a low-intensity light. If the detector measures less than the baseline level when an occupancy sensor determines the space is unoccupied, a high-intensity light is energized and an indication is provided to a user that the low-intensity light has failed. A method provides daylighting operation of a lighting system. An occupancy sensor can have Wi-Fi functionality to enable remote configuration of the sensor. A line voltage occupancy sensor can include an interface with low voltage devices. An occupancy sensor can include an integral interface to enable an external control system to override the sensor's normal logic under emergency conditions. An occupancy sensor can include an active temperature compensation feature. An occupancy sensor can also incorporate an automatically adjustable coverage area.

A lighting system (100A, 100B) comprises a light source (102) for emitting a light beam stripe (220B) with a plurality of light emitting units (603, 803A, 803B) forming an array in the longitudinal direction (X), and an optical element (870) at the exit side of the light source (102) extending across the plurality of light emitting units, and configured to enlarge the beam divergence in the transversal direction. The lighting system (100A, 100B) further comprises a reflector unit, a support structure (210), and a reflective surface (104) with an essentially linear shape in the longitudinal direction (X) and a curved shape in the longitudinal transverse direction (Y), and a chromatic diffusing layer (108) comprising a plurality of nanoparticles embedded in a matrix, wherein the chromatic diffusing layer (108) is positioned such that at least a portion of the reflected light beam (220A) passes through the chromatic diffusing layer (108), thereby generating diffuse light by scattering more efficiently the short-wavelengths components of the light in the visible spectral range than the long-wavelength components of the light in the visible spectral range.

An apparatus and methods for compensating for spatial non-uniformities in solar simulators. This is accomplished in part by acquiring a spatial map of the intensity distribution that the solar simulator produces across the illumination plane using a reference cell, identifying an area of an arbitrary solar cell within the illuminated area, and then calculating the expected illumination levels for that solar cell in that specific location based on the spatial mapping. The results of that process can then be used to determine the efficiency of the arbitrary solar cell during a test in which the reference cell (of known efficiency), located in a different part of the illuminating beam, simultaneously measures the illumination in one area of the illumination beam.

An irradiance adjustment device comprising a radiation source and at least one neutral density filter disposed adjacent to the radiation source, wherein the neutral density filter can be moved into or out of the beam path of the radiation source.

A test apparatus for analyzing performance of a multi-junction solar cell can include a plurality of light source groups, each light source group including three or more light sources distributed over a substrate. Each sub-cell of the solar cell is associated with at least one of the light source groups, and each light source group primarily photoexcites the sub-cell of the light source group with which it is associated. The intensities of the various light source groups can are adjusted such that an output current of each of a plurality of calibration standards is within 2% of a predetermined current value. The test apparatus can then be used to test performance of the multi-junction solar cell.

The present application discloses a LED-based solar simulator light source having at least one LED array formed by multiple LED groups of LED assemblies, at least one field flattening device, at least one diffractive element, and at least one optical element configured to condition the broad spectrum light source output signal and direct the light source output signal to a work surface.