Optical waveguides are recognized as the ultimate path for AR glasses due to their slim profile and high light transmittance. Surface relief grating (SRG) waveguides have become the current mainstream technical direction, though they face bottlenecks such as rainbow artifacts. Silicon carbide (SiC), with its ultra-high refractive index and thermal conductivity, can overcome challenges related to field of view and heat dissipation. In micro-displays, Micro-LED leads comprehensively in brightness, size, and lifespan, offering the highest compatibility with SiC waveguides and is poised to become the next-generation standard, though breakthroughs in full-color mass transfer yield are still needed. Key points are summarized as follows: AR glasses optical solutions are gradually converging, with waveguides regarded by the industry as a key technical route for achieving lightweight consumer-grade products. Prism solutions with only 10°–20° field of view and freeform surface solutions weighing over 500g have been fully phased out. Birdbath solutions, with less than 30% light transmittance and optical efficiency of only 15%–20%, are considered transitional. Waveguides, with their slim form, high light transmittance exceeding 85%, and potential for large field of view, are established as the long-term ultimate route, with thicknesses compressible below 3mm. Among these, surface relief grating (SRG) waveguides balance performance and mass production feasibility, making them the current mainstream choice and the common selection for flagship models from Microsoft, Meta, and leading domestic brands. Geometric waveguides, volume holographic waveguides, and polarization volume holographic waveguides are evolving simultaneously, with the technical landscape becoming clearer. Within waveguide systems, differentiation is evident: geometric waveguides offer the best imaging quality with light leakage rates of only 1%–5%, but suffer from low mass production yield due to nanoscale coating and molecular bonding processes; diffraction waveguides are constrained by grating processing precision and high-refractive-index adhesive materials; SRG waveguides have the best mass production capability but inherent rainbow artifacts, with color fringe intensity only reducible by 30%–50%; volume holographic and polarization volume holographic waveguides theoretically offer higher optical efficiency but are limited by photosensitive material refractive indices, typically achieving 30°–40° field of view, with challenges in environmental stability control. Silicon carbide (SiC) addresses waveguide pain points at the material level, achieving generational breakthroughs in key parameters. With a refractive index exceeding 2.6 and thermal conductivity up to 490 W/m·K, SiC enables single-layer waveguides to surpass 80° field of view, inherently suppresses rainbow artifacts, and eliminates complex heat dissipation structures. Meta's Orion prototype has validated a 70° field of view. Domestically, Sanan Optoelectronics, Tianyue Advanced, and TankeBlue have introduced 4–12 inch optical-grade SiC substrates, though material costs remain high at several thousand yuan per piece, and processing difficulties due to hardness and brittleness persist, placing the technology in the industrialization攻坚 period following initial breakthroughs. Micro-display technology iteration directions are clear, with brightness, size, and power consumption as the three key metrics determining success. LCoS and DLP optical engines, with volumes of 4–6 cc, struggle to adapt to slim designs; LBS volumes are only 0.5–1 cc but face speckle and resolution bottlenecks; Micro-OLED is currently mainstream for mid-to-high-end products, offering contrast ratios up to millions, but brightness is limited to 1,000–6,000 nits with lifespans under 10,000 hours; Micro-LED achieves brightness up to 100,000 nits, volume <0.5 cc, and lifespan over 100,000 hours, offering the highest compatibility with SiC waveguides and positioned as the next-generation standard solution, though full-color mass transfer yield仍需突破. Risks include: 1. Slower-than-expected technological progress, potentially delaying industry industrialization. 2. Slow improvement in core process yields and persistently high costs of key materials, which may constrain the large-scale adoption of AR glasses.
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