Integration of Prism Sheet on Quantum Dot Film With Bridge Patterns to Enhance Luminance of LED Backlight Unit

An integrated prism sheet on quantum dot (QD) film with bridge patterns has been proposed to increase the optical efficiency of an LED backlight unit. The bridge patterns were designed, such that they not only extract the light trapped in a QD film but also change the optical path effectively toward the vertical direction. We verified our design concept and geometrical parameters by optical simulation, and fabricated the integrated optical sheet using a lithography and UV imprinting process. The simulation results show the luminance enhancement of 33.6% after applying the bridge patterns while keeping the same Commission Internationale de l'Éclairage (CIE) after careful controlling the concentration of QDs. The enhancement of luminance toward the vertical directionwas also confirmed experimentally after the fabrication of an integrated prism sheet on a QD enhancement film.