Recently, AI-powered smart glasses with displays and lightweight AR glasses have rapidly emerged, finding wide applications in entertainment, movie watching, translation, education, training, healthcare, and many other fields. Among them, the near-eye display directly determines image quality and user experience. It also accounts for a large proportion of the total cost of near-eye display terminals (hereinafter referred to as XR terminals), making it one of the core components of XR products.
Currently, the mainstream near-eye display technologies chosen by major manufacturers mainly include LCoS, Micro OLED, and Micro LED. Due to the need for backlighting, LCoS cannot achieve complete darkness and also consumes relatively high power. The industry generally believes it will not be the mainstream path in the future. Therefore, this article only discusses Micro OLED and Micro LED.
1. Brightness Requirements and Optical Schemes in AI, AR, and MR Glasses
1.1. Background
A 40W fluorescent lamp has a brightness of about 5,000 nits. The human eye is very sensitive to brightness (eye-entrance brightness). Normally, when the eye-entrance brightness exceeds 1,800 nits, the human eye begins to feel fatigue; when it exceeds 3,000 nits, it causes discomfort.
For AI + AR glasses and MR terminals, the required brightness for most environments is 60–1,200 nits.
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Without obstruction or loss, the light source brightness equals the eye-entrance brightness.
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When optical components are present between the light source and the eyes, the eye-entrance brightness equals the optical efficiency × light source brightness (assuming no additional loss).
In a dim environment, only a few dozen nits of brightness are enough to see clearly. While using computers or smartphones indoors, the typical eye-entrance brightness is about 350 nits. Outdoors, under bright ambient light, the required eye-entrance brightness is about 1,200 nits.
1.2. Formula: Eye-Entrance Brightness of XR Terminals
Eye-entrance brightness = Microdisplay brightness × Optical efficiency
Regardless of whether it is a Micro OLED or Micro LED panel, the emitted light must undergo refraction, reflection, convergence, and transmission through optical components before reaching the human eye. This process determines the final optical efficiency.
1.3. Common Optical Schemes in XR Terminals and Their Efficiencies
For AI + XR products, the first consideration is the brightness that reaches the eyes after passing through optical components, followed by key factors such as weight, size, and cost.
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Mainstream MR/VR → Pancake optics, efficiency above 10%.
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Mainstream AR → Birdbath optics, efficiency above 15%.
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AI or AI + AR glasses → Array or diffractive waveguide optics.
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Diffractive waveguides (SRG process): currently about 0.3%, recently improved to 1.5–2% by leading companies.
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Array waveguides: 6–10%, but with higher manufacturing complexity and cost.
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Birdbath and Pancake optical systems cost only a few dozen RMB, and the weight of each lens is usually 8–13 g, but their size is relatively large. Waveguide optics are much lighter, since the micro–nano structured grating film on the lens surface is nearly weightless. Even including the light engine and coupler, the total weight is only a few grams, with very small size.
At present, waveguide solutions made with different materials and processes are still evolving quickly:
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Array waveguide panels: priced in the hundreds of RMB.
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Diffractive waveguide panels (SRG process): priced above one thousand RMB.
1.4. Brightness Requirements for Displays in XR Terminals
Assume: indoor usage requires 300 nits eye brightness, outdoor requires 1,200 nits eye brightness.
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Pancake optics (MR/VR): near-eye display brightness required = 3,000–8,000 nits.
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Birdbath optics (AR glasses): display brightness required = 10,000+ nits.
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Array waveguides (6% efficiency): display brightness required = 20,000+ nits.
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Diffractive waveguides (0.1% efficiency): display brightness required = 1,000,000 nits.
Clearly, only Micro LED can meet such extreme brightness demands. However, once diffractive waveguide efficiency reaches 6%, the choice of display technology will broaden significantly.
2. In-Depth Analysis of Micro LED
2.1. Technology Readiness
Full-color Micro LED display solutions mainly include:
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Optical beam combination
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RGB vertical stacking
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Quantum-dot color conversion
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Monolithic epitaxy
If technology maturity (Technology Readiness Level, TRL) is divided from 1–9 into laboratory (1–3), pilot (4–6), and mass production (7–9):
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Quantum-dot conversion and monolithic epitaxy: still in the laboratory stage.
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Optical beam combination (using prisms to combine RGB Micro LEDs): most mature, TRL 6–7, but issues remain in wavelength consistency and light path control.
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RGB vertical stacking: highly favored by investors but still faces major challenges (blue light leakage, yield, wavelength uniformity, equipment). Currently TRL 3–4.
2.2. Cost–Performance Analysis
Due to complex processes, large equipment investment, and low yield, Micro LED remains costly:
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Full-color Micro LED displays: RMB 2,000 to tens of thousands.
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0.13-inch, 480P full-color Micro LED (1K units): over RMB 2,000.
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Even single green devices: over RMB 500.
2.3. Time to Market
To achieve AI + AR applications with high pixel density and mass-market pricing (~RMB 200 or less), breakthroughs are needed in substrates, chip structure, bonding, and colorization. This may take 7–10 years.
(Apple disbanded its Micro LED team in April 2024 for this reason.)
2.4. Compatibility with Optics
Micro LED’s ultra-high brightness (hundreds of thousands to millions of nits) makes it best suited for waveguide optics.
2.5. Industry Landscape
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Only JBD (Shanghai Xianyao Display Technology Co., Ltd.) has commercialized full-color Micro LED at scale.
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A few others, such as Raythink, have released prototypes.
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Giants such as Samsung and BOE have not launched AR/AI Micro LED products, instead focusing on Micro OLED for AR/AI glasses, and applying Micro LED to TVs and non-consumer markets.
3 In-Depth Analysis of Micro OLED
3.1. Technology Readiness
Micro OLED is rapidly transitioning from the older WOLED (white OLED + color filter) method to the new semiconductor photolithography direct RGB emission.
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WOLED: already mass-produced, TRL 8–9. It produces white light through RGB stacking, then uses filters to extract RGB. This leads to major efficiency losses, requiring tandem (multi-layer stacking) to increase brightness. However, more layers lower yield and raise cost.
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Photolithography Micro OLED: directly deposits organic layers (R/G/B) on the substrate and uses photolithography for precise patterning. This improves aperture ratio from ~30% (WOLED) to over 70%.
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Pixel density: >10,000 PPI
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Brightness: >10,000 nits
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Lifetime: 3× WOLED
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Yield: up to 80% at 10,000 nits brightness
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Process steps reduced by 50% → lower cost
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Japan Display released photolithography Micro OLED in May 2022. Samsung and others are following. TRL: 7–8.
3.2. Cost–Performance Analysis
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Sony WOLED MR panel (1.3 inch): USD 350.
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AR panels (0.23–0.68 inch): tens of USD.
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Photolithography Micro OLED (0.15–0.23 inch, 720P–1080P): USD 5–10.
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Full-color photolithography Micro OLED: under USD 30 (less than one-tenth the cost of equivalent Micro LED).
3.3. Time to Market
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Samsung: mass production expected 2026.
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Aoshi Technology (China): building production line, also targeting 2026.
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Samsung and SEL (Japan): 15,000 nit full-color Micro OLED in 2024; samples up to 60,000 nits already reported.
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Single-color (green) Micro OLED can exceed 100,000 nits.
3.4. Compatibility with Optics
Micro OLED can be adapted to all optics: Birdbath, Pancake, freeform, array waveguide, diffractive waveguide.
(Current diffractive efficiency still requires further brightness improvement.)
3.5. Industry Landscape
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WOLED producers: Sony, BOE, Seeya.
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Photolithography RGB Micro OLED producers: JDI (eLeap), Samsung (Real RGB), Aoshi (POLED), Visionox (ViP).
4. Commercialization Status of Micro OLED vs. Micro LED in AI and XR
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Meta Orin prototype (2024): dual-eye full-color Micro LED → cost USD 10,000 → canceled. Final product used LCoS + array waveguide, priced at USD 799.
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Chinese AI glasses: 480P LED + waveguide, priced over RMB 3,200. (Single-screen designs cause dizziness for some users.)
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Full-color Micro LED + diffractive waveguide: USD 9,000+ for monocular, USD 13,000+ for binocular.
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AI glasses with camera: require ≥720P full-color. Multiple companies (e.g., Gudong Technology) are adopting Micro OLED + array waveguide.
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Office/AR use: requires ≥1080P.
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AR for video playback: requires ≥2K.
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MR/VR: requires ≥4K.
Currently, Micro OLED is the mainstream choice for AR, MR, and VR due to its broad optical compatibility.
5. Conclusion
Before mass production of next-generation Micro OLED and diffractive waveguides, consumer AI glasses based on LCoS + array waveguides offer the best cost–performance.
With improvements in materials and processes, waveguide optics are rapidly advancing. Once diffractive waveguide efficiency reaches 4% (expected by 2027) and mass production begins, photolithography Micro OLED + diffractive waveguides will likely dominate AI + AR applications.
The idea that Micro LED is the “ultimate solution” for AI + AR glasses is based on the assumption that waveguide efficiency will not improve. In reality, no single technology is ultimate—both market demand and technology evolve.
For consumer electronics, Micro LED’s ultra-high brightness and lifetime are unnecessary. Its main future applications will be in large displays, outdoor signage, projection, and industrial scenarios requiring extreme durability.
Meanwhile, photolithography Micro OLED already meets brightness and lifetime requirements, avoids burn-in issues, supports extremely small sizes (down to 0.1 inches), and equals or surpasses Micro LED in power consumption, response speed, and color performance. With strong cost advantages, Micro OLED is highly likely to follow the same path as smartphone OLEDs and become the mainstream display technology in wearable consumer electronics.
