The Measurement Of Spatial Chromaticity Of LED

Compared with conventional light sources, LED light source has a small size, low power consumption, long life, no pollution and so on. In recent years, with the improvement of LED luminous efficiency and application of the technology, LED light source will become the main light source after the incandescent lamp, fluorescent lamp and gas discharge lamp. Spatial chromaticity difference of LED light source, in particular GaN-based blue chip, phosphor coated white LED light source, will seriously affect the visual effects of lighting. Therefore, the measurement of LED light source's spatial chromaticity difference becomes a major international research project.Basing on the principle of photometry and colorimetry, this paper discussed the LED's spatial chromaticity difference and shown a new method to measure it. In order to achieve rapid high-precision measurement of spatial chromaticity difference, the author proposed to use a tristimulus colorimeter for color measurement with a common CCD spectrometer for correction. Three methods were used to correct the measurement results of the tristimulus colorimeter, theoretical simulation and experimental analysis were done to evaluate the advantages and disadvantages of each method.To improve the measurement accuracy of CCD spectrometer, we used mercury lamp and monochromator to calibrate the wavelength of spectrometer, made relevant programs on the linear calibration of the CCD spectrometer, used the monochromator to get the SDF response of the CCD spectrometer, used matrix algorithm to calibrate the stray light of the CCD spectrometer, and achieved good results.