Optical Analysis of Color Distribution in White LEDs With Various Packaging Methods

Uniform color distribution is essential for the packaging of light emitting diodes (LEDs). The Monte Carlo ray tracing method is applied to analyze the color distribution of white LEDs. Five packaging methods are investigated and the location of phosphor layer is varied. Results reveal that the packaging method is the primary factor affecting the color distribution and a nonreflector packaging method presents better color uniformity. The location of phosphor has a small impact on the color uniformity but remote location, if too far, can reduce the uniformity significantly. The reduction of color uniformity may exceed 88%.