The correction method for led spectrum measurement in the total flux mode

摘要

The integrating sphere is used to measure the spectral distribution and calculate the chromaticity coordinates of LEDs. It usually has to consider the self-absorption when the light source is radiating in the integrating sphere. The LED with colourd parts, such as the printed circuit board, heat sink and so on, should be careful in particular. The case of the large enough sphere, the self-absorption spectra of LEDs have almost flat spectral distribution and their absorption are few. Hence, the chromaticity coordinates of LEDs are almost same, even if the self-absorption corrections are calculated or not. In the small sphere case, the self-absorption of LEDs have the spectral distribution by the coloured parts and are given some influence to calculate the chromaticity coordinates. After having the spectral correction, the chromaticity coordinates of the LEDs accord with the large sphere case. When the LED having coloured parts are radiated inside the integrating sphere, those plates are directly irradiated. In such a case the spectral correction functions effectively for the chromaticity coordinates.