Design And Optimization Of Remote Phosphor LED Backlight

White light-emitting diodes (WLED) are widely used in lighting and liquid crystal display (LCD) industry due to the advantages of high efficiency and environmental protection. LED backlight units used for LCD develop rapidly. The LED backlight unit's performance depends on the parameters of lifetime, luminous efficiency, color gamut etc. About these parameters, a remote phosphor technology using the phosphor as dot pattern on light-guiding plate (LGP) is studied in the paper.Firstly, thermal and optical properties of LED backlight unit are simulated respectively. The result indicates that remote phosphor technology can reduce the temperature of LED chips and improve luminous efficiency of backlight unit.Then, focusing on the traditional side-emitting LED backlight plate, the distribution of dot pattern is designed and optimized to obtain high luminance uniformity. The practicability of the design scheme is validated by preparation and measurement of the samples. The optimal distribution of dot pattern is used on remote phosphor LED backlight whereas the color temperature is uneven.Focusing on the problem above, the relationship between the uniformity of color and dot pattern distribution is explored in further. The uniformity of color temperature is improved to 96.6%by the structure optimization.The feasibility of blue LED backlight plate structure with remote yellow phosphor dot pattern is verified but the color gamut is required to be improved. Quantum dots are blended in yellow phosphor to compensate the lack of green light and red light in traditional yellow phosphor. The simulation results show that the color gamut increases from 73.8% to 94.8%. The potential application of remote phosphor dot pattern backlight plate using the yellow phosphor combined with red and green quantum dots in LCD is proved.In summary, remote phosphor technology can prolong the life of LED backlight unit and improve luminous efficiency. The uniformity of luminance and color temperature will be improved by structure optimization. In addition, color gamut can be improved by mixing quantum dots in phosphor.