LED조명의 스펙트럼과 S/P ratio 관계에 관한 연구

Abstract

Since LED lightings were presented as new lighting technologies, researches have been performed on the photopic vision, the scotopic vision and the mesopic vision under the LED lightings. The S/P ratios of the warm and the cool white LEDs are 1.2 and 2.04, respectively, as specified in the IES-TM12-12. In this paper, the S/P ratios in the CCT range of 3000 K to 6000 K are simulated according to the changed of the spectral characteristics such as peak wavelengths and full widths at half maximum of RGB 3-chip and RGBY 4-chip LEDs. Spectral power densities of RGB and RGBY LEDs were generated by the Gaussian distribution composed of peak wavelength and full width at half maximum. As scanning the peak wavelengths of RGB and RGBY SPDs, CRIs and S/P ratios were simulated. And also the full width at half maxima increased by some proportions to make changes in S/P ratio. Thus, the variations of S/P ratio and CRI were represented from the simulation results. As results in warm white regions(CCT 3,000 K and 4,000 K), RGB LEDs showed S/P ratio of 3.2 and 4, respectively. In cool white regions(CCT 5,000 K and 6,000 K), RGB LEDs showed S/P ratio of 4.3 and 4.7, respectively. But CRIs were degraded as S/P ratio increased with RGB LEDs. Using RGBY LEDs, in the CCT ranges from 3,000 K to 6000 K, S/P ratios from 1.8 to 2.7 were achieved with relatively higher CRIs than those from RGB LEDs.