As display technology continues to progress, worldwide big names have launched innovative displays that the resolution has evolved from full HD to 4K. Nevertheless, without high contrast, the refined display performance of high resolution would not be fully presented. High contrast intensifies the brightness and darkness of images and videos on TVs and gaming monitors and enables AR wearables or automotive displays to deliver clear picture under sunlight. Thus, the demands for high contrast display keep rising. LEDs, with its self-emitting feature, can be adopted to various ...