Different color temperature white LEDs are mixed into a bundle of white light, and the luminous flux of the mixed white light is the sum of the luminous fluxes of the white LEDs of different color temperatures.
The color temperature spectral power distribution curve of the mixed white light is a spectral power distribution curve in which a spectral power distribution curve of different color temperature white LEDs is superimposed and mixed to form a new color temperature, thereby determining the color temperature value of the mixed white light.
By changing the driving currents of different color temperatures, thereby changing the luminous flux of different color temperatures, and changing the spectral power distribution curves of different color temperatures, the new spectral power distribution curves generated by different color temperatures are superimposed and mixed to form a new spectral power distribution curve. Get dynamically adjustable white light.
At present, there are two methods for realizing white LEDs with adjustable color temperature and high color rendering
(1) Using a multi-chip plus phosphor, such as a module consisting of at least two blue chips, a yellow chip, and a green phosphor and a red phosphor, to produce a white light with a color temperature adjustable high color rendering index (Ra 80) LED lights. However, the excitation efficiency of the red phosphor excited by blue light is low, resulting in low brightness of the LED lamp and poor practicability.
(2) Using different color LED combinations, such as white light plus red and blue LED combination, by controlling the driving currents of white, red and blue LEDs respectively, to realize adjustable white light with color rendering index greater than 90 in different color temperature ranges, but the driving circuit is complex and costly high.