Omnidirectional color shift suppression of full-color micro-LED displays with enhanced light extraction efficiency

Abstract

The three-primary-color chip array is the most straightforward to realize full-color micro-LED displays. However, the luminous intensity distribution shows high inconsistency between the AlInP-based red micro-LED and GaN-based blue / green micro-LEDs, resulting in the issue of angular color shift with different viewing angles. This Letter analyzes the angular dependence of color difference of conventional three-primary-color micro-LEDs, and proves that the inclined sidewall with homogeneous Ag coating has a limited angular regulation effect for micro-LEDs. Based on this, a patterned conical microstructure array is designed on the micro-LED’s bottom layer to effectively eliminate the color shift. This design cannot only regulate the emission of full-color micro-LEDs to perfectly meet Lambert’s cosine law without any external beam shaping elements, but also improve the light extraction efficiency of top emission by 16%, 161%, and 228% for red, green, and blue micro-LEDs, respectively. The color shift Δu ′ v ′ of the full-color micro-LED display is also kept below 0.02 with the viewing angle ranging from 10° to 90°.

P‐4.25: AR Waveguide Display with Enlarged Eyebox Based on Polarization Volume Gratings

“…The glass substrate with refractive index of 1.51 and thickness of 1 mm was used as the waveguide, and the transverse period of 422.8 nm was used to prepare the waveguide structure of this configuration with the coupling grating size of 45 mm × 25 mm. LCOS optical engine (LCE2201F), LCOS optical engine provides 30.6 °× 17.7 °to input virtual images [19] . A camera was placed 15 mm away from the coupling area to capture the imaging results of the AR.…”

Recent advances in micro-pixel light emitting diode technology

“…An inclined sidewall has often been adopted to redirect the in-plane transverse magnetic (TM) photons toward the substrate for extraction, thus enhancing the LEE of lLEDs. [99][100][101][102][103] For example, it has been shown that deep ultraviolet (DUV) lLEDs (k ¼ 280 nm; chip size ¼ 20 lm) with a sidewall angle of 33 yielded a 19% higher EQE than those with an inclination angle of 75 . 99 This improvement was attributed to the fact that more photons underwent total internal reflection (TIR) with the 33 -inclined sidewall, resulting in a higher LEE [Figs.…”

Enhancing the Performance of GaN-Based Light-Emitting Diodes by Incorporating a Junction-Type Last Quantum Barrier

“…Nitride light-emitting diodes (LEDs) have garnered increasing attention and extensive amounts of research due to their low power consumption and compact size [1][2][3]. One common problem facing GaN-based LEDs is that the electrons can be easily injected from the active regions into the p-GaN region, which decreases the recombination of the carriers within the active regions, owing to the high mobility and small effective mass of the electrons.…”