Fig. 1. (a) Working principle of diffractive waveguide-based AR device. (b) Temperature distribution at different power consumption. Reprinted from Ref. 2 under a Creative Commons license.

Fig. 2. (a) Working principle of LED. (b) 3T1C circuit for PWM driving. Adapted with permission from Ref. 8, © Optica 2021. (c) Digital PWM input data. (d)–(i) Schematic of (d) monochromatic, (e) X-cube, (f) parallel, (g) QDCC, (h) nanowire, and (i) full-color-subpixel $\mathit{\mu }\mathrm{LED}$.

Fig. 3. (a) Wafer bonding. (b) Flip-chip bonding. (c) Percentage of defect regions in $\mu \mathrm{LED}$. (d) Measured size-dependent peak EQE of $\mu \mathrm{LEDs}$ on wafer. Adapted with permission from Ref. 24, © AIP Publishing 2020. (e) ALD surface passivation. Reprinted with permission from Ref. 27, © Optica 2018. Continuous MQW $\mu \mathrm{LED}$: (f) structure and (g) optical crosstalk. Reprinted with permission from Ref. 33, © John Wiley and Sons 2024.

Fig. 4. (a) Size-dependent $\mu \mathrm{LED}$ EQE on panel.^24,33–38" target="_self" style="display: inline;">^–38 (b) Calculated power consumption of $640\times 480\mu \mathrm{LED}$ panels with a subpixel size of $4\mu \mathrm{m}$ to provide 3-lm luminous power to the in-coupler. (c) Power consumption comparison between the calculated X-cube 3-panel $\mu \mathrm{LEDs}$ and measured TCL RayNeo X2 when producing 2-lm luminous power.

Fig. 5. (a) Working principle of OLED. (b) Working principle of tandem OLED. (c) Schematic of white $\mu \mathrm{OLED}$. (d) Schematic of RGB $\mu \mathrm{OLED}$. (e) Schematic of birdbath structure. (f) Power consumption of RGB $\mu \mathrm{OLED}$ and white $\mu \mathrm{OLED}$. Dots are measured data from Refs. 70 and 71.

Fig. 6. (a) The architecture of a typical LCoS device. (b) Two major LC modes. (c) Fringe field effect in LCoS devices. (d) Zonal illumination architecture. Reprinted with permission from Ref. 87, © John Wiley and Sons 2024. (e) The schematic of the gray box when the ambient light is not bright. Reprinted with permission from Ref. 87, © John Wiley and Sons 2024. (f) Front-lit illumination developed by Himax. Reprinted with permission from Ref. 92, © John Wiley and Sons 2023. (g) Compact LCoS with novel illumination architecture: in-coupling prism, light guide plate, and extraction prisms. Reprinted from Ref. 93 under a Creative Commons license. (h) Compact LCoS with four thin PBS cuboids and two half-wave plates. Reprinted from Ref. 94 under a Creative Commons license.

Fig. 7. (a) The architecture of a typical DLP device. Reprinted with permission from Ref. 96, © IEEE 2012. (b) R/B 2-in-1 illumination system.⁹⁷ (c) Freeform compact illumination system. (b), (c) Reprinted with permission from Ref. 97, © SPIE 2023.

Fig. 8. (a) The architecture of a typical LBS device. (b) OQmented 2D MEMS mirror. Reprinted with permission from Ref. 100, © SPIE 2021. (c) Estimated power consumption of 1 mm fast piezoelectric mirror driving at 35 kHz. (d) Estimated power consumption of 2D piezoelectric mirror slow axis driving at 600 Hz. Red dots indicate the calculated power consumption of OQmented MEMS mirror at resonant conditions.

Fig. 9. (a)–(c) Schematic of virtual image quality in AR eyewear (a) without dimmer, (b) with global dimmer, and (c) with pixelated dimmer. Reprinted with permission from Ref. 115, © John Wiley and Sons 2024. (d) The architecture of EC modulation smart window. Reprinted from Ref. 116 under a Creative Commons license. (e) The architecture of film-compensated homogeneous LC smart window. (f) The architecture of dye-doped LC smart window.

Fig. 10. (a), (b) Calculated power consumption of commonly employed microdisplay light engines for AR glasses at the current stage when producing (a) 3-lm and (b) 1-lm luminous power. (c), (d) Calculated power consumption of microdisplay light engines with improved architectures when producing (c) 3-lm and (d) 1-lm luminous power. CMQW stands for JBD’s continuous MQW.