Silicon-based Micro LED micro-display full-color technology sharing

26 views admin 2025-02-28

Micro LED uses micron-level LED as pixel light-emitting unit, with multiple advantages such as high brightness, high contrast, high pixel density, and splicing. It is currently considered to be the most suitable display technology for AR. The current Micro LED full-color technology is mainly divided into three categories: color combination technology, quantum dot technology and monolithic stacking technology.

Color combination technology At present, the technology that has been mass-produced in the AR field of full-color Micro LED is color combination technology, 1) X-Cube color combination (prism color combination): R, G, B three monochrome panels are fixed on the three faces of X-cube (prism) respectively. The three colors are emitted through the fourth face after X-cube color combination, and are collimated and projected by a group of micro lenses. The X-cube solution module volume is less than 1.4cc. 2) Optical waveguide color combination: Use R, G, B three independent monochrome light machines for color combination, generally with multi-layer optical waveguide/multiple waveguide coupling ports to achieve color combination.

Quantum dot technology uses UV/blue LED to excite quantum dots or phosphor materials to achieve color conversion. Due to the large particle size of phosphors, quantum dots are generally used. After being excited, quantum dots are easy to adjust the emission wavelength of the emitted light, and can emit RGB three-color light, and achieve full color through color matching. Since quantum dots have a narrow half-peak width and a wide absorption spectrum, and the luminous efficiency is very high, the displayed color purity and saturation are high. At present, the challenges of the practical application of quantum technology are mainly poor material stability, short life, and poor color uniformity.

Monolithic stacking technology Monolithic full-color Micro LED has a wider application value, a larger field of view, and a smaller optical machine volume. It simplifies the system-level integration of AR glasses, reduces optical losses, and can achieve higher waveguide collimation efficiency. 1) In February 2023, the MIT team used two-dimensional material layer transfer to develop a full-color vertically stacked Micro LED with an array density of 5100PPI, a size of only 4μm, and a stacked structure height of 9μm; 2) In August 2023, JBD released the world's first 0.22-inch 2K resolution monolithic full-color vertically stacked Micro LED prototype Phoenix. The total thickness of the Phoenix prototype stack is less than 5μm, which can minimize absorption losses in the cavity. In addition, the native epitaxial material can emit high-flux density light, and ultimately can achieve a brightness of up to 1 million nits. In addition, the full-native color scheme can achieve a narrow half-maximum full-width FWHM spectrum with higher color quality and purity. The prototype is scheduled for mass production in 25 years.