Low-color tolerance mixing algorithm for nonlinear color spaces and applications

Smart lighting fixtures using Pulse Width Modulation (PWM) control can emit different colors of light by adjusting the duty cycles of different LED channels. The traditional Grassmann theorem is limited to calculating the duty cycles for up to three LED channels and fails to account for the nonlinear variations in the photometric and electrical parameters of LEDs, leading to high Standard Deviation of Color Matching (SDCM) in mixed color output. This work develops a comprehensive method for calculating the duty cycles for color mixing, which, given the basic photometric and electrical parameters of LEDs, can directly calculate the duty cycles for achieving target colors with three or more LED channels. The results of color mixing for Red-Green-Blue (RGB) LEDs and Red-Green-Blue-White (RGBW) LEDs with SDCM < 6 demonstrate the feasibility of this method. This approach is effective for mass production of low color tolerance lighting fixtures.