Measure LED relative spectral power distribution Pλ, chromaticity coordinates (x,y),(u,v), correlation color temperature Tc, Color rendering index Ra, color tolerance SDCM, peak wavelength λp, spectral half-width △λ, main wavelength λd, color purity , luminous flux lm, luminous intensity (with test standard), luminous effect, forward voltage, reverse leakage current and other photochromic performance parameters.