The SLMS system consists of a 4-inch diameter integrating sphere, a Diode Array Spectrometer, a regulated-current lamp power supply, and Labsphere SLMS software. Also included is a calibrated spectral flux standard, as well as an auxiliary lamp, which may be used to correct absorption errors.
Light collected by the sphere is measured by the spectrometer, which computes the lamp's radiant flux as a function of wavelength. This spectral data is processed by the system software in order to compute total luminous flux and color properties such as chromaticity, correlated color temperature, and color rendering indices. Properties particularly applicable to LEDs can also be calculated: peak, central, and centroid wavelength; spectral bandwidth; dominant wavelength; and purity.
