Chromaticity analysis of diffraction pattern of white light under the grating

From the D65 daylight source, the ten monochromatic lights were evenly selected to be mixed into white light. After grating diffraction, color mixing was performed by using the chromaticity method with the relative intensity as the proportionality factor. The mixed color and its chromaticity parameters at specific diffraction angle positions were obtained to calculate L*, a*, b* and dominant wavelength. The relationship between the parameters of the grating and the chromaticity parameters of the mixed color was studied separately. The results showed that the color of the white light diffraction pattern at the diffraction angle θ = 2° is most significantly affected by d, followed by N. There is well linear correlation between b and L*, a*, b* values; but the effect of b on the color is not obvious. Then the relationship between the light intensity of ten kinds of monochromatic lights and the grating constant according to the grating diffraction intensity equation were drew, and the “rainbow” phenomenon was found. Current method for calculating the average wavelength of mixed colors directly from the “rainbow” graph is verified to be equivalent to the chromaticity method.