P‐206: Late‐News‐Poster: Lattice Patterned Micro Lens Array (MLA) Optical Films for Mini‐LED Back Light Units (BLUs)

Abstract

A spatially modulated, direct‐lit back light unit (BLU), also known as mini‐LED BLU, is becoming a preferred solution for a high dynamic range (HDR) LCD based display system. With localized dimming, an LCD based display can offer contrast characteristics that are similar to an emissive display system such as OLED. A major challenge facing mini‐LED BLU film stack design, is transforming the grid emission pattern of a mini‐LED array into a uniform luminance area light source. This is particularly true for mobile devices where BLU thickness, or optical distance (OD), must be minimized. We have demonstrated Micro‐Lens Array (MLA) solutions that efficiently eliminate hot spots induced by a mini‐LED array within extremely short OD. Films with various optical structures were analyzed and used to create a high‐performance optical layer within the mini‐LED BLU film stack. To further enhance performance, we propose and demonstrate the concept of a spatially modified MLA optical film with a "lattice" pattern matching the mini‐LED array. Lattice optical films were designed and fabricated at Bright View Technologies and substantial performance enhancements were experimentally demonstrated.

Mini-LED Backlight Technology Progress for Liquid Crystal Display

“…Zheng et al added a specially designed micro structure film between the brightness enhancement film (BEF) and diffuser plate [14]. Shen et al used the lattice patterned micro lens array optical films above the Mini-LED dimming array [46]. Some researchers also placed the translucent layer [47,48], which has reflective and transmissive properties, or the birefringent light-shaping film [49] on the Mini-LED chip.…”

Design of microstructure optical film for high uniform mini-LED backlight

“…In a previous work, Feng et al 15 designed a TIR-based microstructure optical film for Micro-LED backlighting. Some of the microstructure optical films proposed in the related research literature need to be strictly aligned with the Mini-LED, which is difficult to achieve in practical applications; some of them are designed only on the upper surface of the optical film; and some of them need to be paired with diffuser plates in order to achieve a high illumination uniformity [16][17][18] .…”