Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

Abstract

Abstract A common full-color method involves combining micro-light-emitting diodes (LEDs) chips with color conversion materials such as quantum dots (QDs) to achieve full color. However, during color conversion between micro-LEDs and QDs, QDs cannot completely absorb incident wavelengths cause the emission wavelengths that including incident wavelengths and converted wavelength through QDs, which compromises color purity. The present paper proposes the use of a recycling-reflection color-purity-enhancement film (RCPEF) to reflect the incident wavelength multiple times and, consequently, prevent wavelength mixing after QDs conversion. This RCPEF only allows the light of a specific wavelength to pass through it, exciting blue light is reflected back to the red and green QDs layer. The prototype experiment indicated that with an excitation light source wavelength of 445.5 nm, the use of green QDs and RCPEFs increased color purity from 77.2% to 97.49% and light conversion efficiency by 1.97 times and the use of red QDs and RCPEFs increased color purity to 94.68% and light conversion efficiency by 1.46 times. Thus, high efficiency and color purity were achieved for micro-LEDs displays. Graphical Abstract