Feedback-Enhanced Color Purity Film for Improved Color Saturation and Conversion Efficiency in Full-Color Micro-LED Displays

Achieving full-color micro-LED display technology typically involves arranging red, green, and blue (RGB) chips into pixels or combining blue chips with quantum dots and other colorconversion materials. Although InP quantum dots offer a cadmium-free solution, their broader spectral full width at half maximum (FWHM) limits color saturation in displays. This study proposes a feedback-enhanced color purity film (FE-CPF) to improve color saturation and conversion efficiency. The proposed FE-CPF optimizes the FWHM of the light emitted after the blue micro-LED light source passes through the conversion layers made from InP green and red quantum dots, achieving high color purity while enhancing the color conversion efficiency. The experimental results indicate that the micro-LED blue light source emits at a wavelength of 447.5 nm. With the application of FE-CPF to the InP quantum dot color conversion layer, the color purity of green quantum dots increased from 76.8% to 95.8%, and that of red quantum dots increased from 85.4% to 99.2%. The conversion efficiencies of green and red light were 1.45 and 1.51 times higher, respectively. The NTSC coverage increased to 145.1%. Future applications of this approach to micro-LED displays promise advanced full-color rendering with high color saturation and energy efficiency.