Design of self-luminous pico-projection optical engine based on a quantum-dot color converted micro-LED

Abstract

Micro-LED will probably become the next epochal display technology, which has combined the advantages of liquid crystal display (LCD) and organic light-emitting diode (OLED). Its self-luminous characteristic will greatly compress the volume of the projection optical engine into truly pico-projection level. However, the relevant design and research are still insufficient. In this paper, we design a four-piece sphere lens group with a 5 mm focal length for micro-LED pico-projection, and then a simulation model of self-luminous projection optical engine is built for demonstration. The total length of the projection lens group is only 8.2mm, the modulation transfer function (MTF) is higher than 0.5@66lp/mm, and the distortion is below 1%. The irradiance distribution shows that the light efficiency is 44.9 % and the uniformity reaches 81.3% when the light divergence angle of micro-LEDs is set to 30°. Then, we explore the influence on light efficiency with different light source divergence angles and determine the optimal range of divergence angles. Finally, a R/G/B integrated micro-LED source with blue light and the above red/green quantum-dot color conversion (QDCC) layer is built, proving the feasibility of a full-color pico-projection optical engine with a single-integrated micro-LED chip.

Design of micro-LED pico-projection optical engine based on an image fiber

“…Therefore, micro-LED is regarded as the cornerstone of next-generation display technology [12], and it has also become the best choice as an image source for self-illuminating pico-projection. The use of micro-LED as the image source greatly simplifies the structure of the projection system and reduces its volume [13][14][15][16]. The self-illuminating projection optical system only needs an image source, a beam shaper element and a projection lens, which simplifies the traditional projection structure's light source module and relay optical module.…”