What is MicroLED, and why does it matter for wearables?

MicroLED is a display technology in which every pixel, or every subpixel, is its own microscopic inorganic LED, so the panel makes its own light without a backlight. In wearables it matters in two different forms: as a direct-view screen on a watch, and as a tiny, very bright microdisplay that feeds the optics in AR glasses. Its main rivals are OLED (including micro-OLED on silicon) and LCoS, and each wins on different terms.

How the three technologies make an image

A 2021 review of AR and VR displays in Light: Science & Applications groups them this way:

MicroLED and micro-OLED are self-emissive. Each pixel emits light. The review notes that self-emissive microdisplays can reach a contrast ratio above 10⁶:1, because an off pixel emits nothing.
LCoS (liquid crystal on silicon) modulates light it does not make. Each pixel changes the polarization of light reflected from it. The review explains that LCoS needs an illumination system with LED or laser light, a linearly polarized source, and either colour filters or colour-sequential addressing to show colour. OmniVision, an LCoS maker, says its panels use up to 6 colour fields.
Other light engines. The same review also covers DMD (digital micromirror device; DLP is the commercial name it is usually sold under, which is our note, not the review's), which, like LCoS, reflects light from an illumination source, and MEMS laser beam scanning (LBS), which scans red, green and blue laser beams with tiny mirrors to draw the image. It notes that self-emissive microdisplays are usually more compact than LCoS and DMD because they need no illumination optics.

In glasses, none of these is viewed directly. The microdisplay sits in the frame and its image travels through a combiner, often a waveguide, to the eye. The 2021 review describes a typical AR combiner as having an optical efficiency below 10%, and says that to show about 1,000 nits to the eye with an ambient contrast ratio above 3:1, designers compare light engines at 10,000 nits. That is why a microdisplay's own brightness figure and "brightness at the eye" are very different numbers.

Brightness: panel figures vs eye figures

JBD, a MicroLED microdisplay maker, publishes both kinds of figure, for two different products:

JBD product	Figure JBD publishes	Power JBD states
Hummingbird 0.13" MicroLED microdisplay (monochrome panel)	Up to 10 million nits (green), 6,350 PPI	60 mW typical
Hummingbird I binocular polychrome optical module (with diffractive waveguides)	6,000 nits eye-brightness	300 mW typical

These are separate products, one monochrome and one polychrome, so the table is an illustration of the two kinds of figure, not a measurement of how much light one optical path loses. For that, use the review's combiner figure above.

When a spec sheet quotes nits for smart glasses, check whether it is the panel or the light reaching the eye. Even Realities, for example, lists its G1 glasses with a Micro LED display, green only, at 1,000 nits; its page does not say whether that figure is measured at the panel or at the eye.

Efficiency: better on paper, harder in practice

The case for MicroLED efficiency is real but conditional.

A 2020 review in Light: Science & Applications comparing mini-LED, micro-LED and OLED found that OLED efficiency stays flat in normal operation but rolls off as luminance rises, while LED chips peak at higher luminance. In other words, the advantage shows up most when the display must be very bright, as in sunlight.
The same review warns that LED efficiency depends on chip size: very large chips have exceeded 80% external quantum efficiency for blue, but micro-LEDs under 50 μm lose a significant amount to sidewall effects and poor light extraction. Red LEDs made from AlGaInP suffer a worse drop at small sizes than blue and green, the 2021 review adds.
For complete AR light engines, the 2021 review's estimates are close together: around 5 lm/W for combined RGB micro-LEDs, around 10 lm/W for blue micro-LEDs with quantum-dot colour conversion (assuming perfect conversion), about 4 to 8 lm/W for micro-OLED, and around 10 lm/W for a colour-sequential LCoS engine.

Our reading of these figures, an inference rather than a finding of either review: "MicroLED is more efficient" holds most clearly for very bright displays, and for full-colour glasses the reviewed estimates did not show a large lead. These are 2020 and 2021 estimates; newer devices may differ.

Cost and manufacturing

The 2020 review names mass-transfer yield and defect repair, moving millions of tiny LEDs onto a backplane and fixing the failures, as the largest remaining challenges, and says they will affect cost. It also names burn-in and lifetime as open issues for OLED, which is part of MicroLED's appeal for always-on screens. The review states the problems; it gives no price figure, and neither does this page.

Comparison

	MicroLED	OLED / micro-OLED	LCoS
Light source	Each pixel emits	Each pixel emits	External LED or laser illumination
Contrast	Above 10⁶:1 possible (self-emissive)	Above 10⁶:1 possible (self-emissive)	Depends on illumination and optics
Colour	Hard; red efficiency drops at small sizes	Full colour on one panel	Colour filters or colour-sequential fields
Known weakness	Mass-transfer yield and repair	Burn-in and lifetime	Needs illumination optics and polarized light
Example	JBD microdisplays; Even Realities G1	Apple Vision Pro (micro-OLED)	OmniVision panels for AR and VR

When each makes sense

MicroLED: glasses that must be readable outdoors with a small, low-power projector, especially monochrome text and notifications; watch faces where burn-in matters.
Micro-OLED: headsets and viewers where full colour and pixel density matter more than extreme brightness. Apple lists micro-OLED displays with 23 million pixels for Vision Pro.
LCoS: full-colour projection from a single panel with colour-sequential fields, accepting the extra illumination optics.

In the index

Display glasses and headsets are in the AR glasses category: the Even Realities G1 (MicroLED), the XREAL One Pro and Apple Vision Pro (micro-OLED). Watches, including the Garmin fēnix 8 Pro, whose entry records a MicroLED display, are under wearables. Manufacturer figures here were checked against their pages on 29 September 2026; the index does not measure displays.

Sources

Xiong, Hsiang, He, Zhan and Wu, "Augmented reality and virtual reality displays: emerging technologies and future perspectives", Light: Science & Applications 10, 216 (2021) (micro-LED and micro-OLED self-emissive, contrast above 10⁶:1, more compact than LCoS and DMD; typical AR combiner optical efficiency below 10%, 1,000 nits to the eye vs 10,000-nit engines; DMD and MEMS laser beam scanning; LCoS reflective, needs LED or laser illumination and polarized light; red AlGaInP efficiency drop; light-engine efficacy estimates of ~5, ~10, 4–8 and ~10 lm/W): https://www.nature.com/articles/s41377-021-00658-8
Huang, Hsiang, Deng and Wu, "Mini-LED, Micro-LED and OLED displays: present status and future perspectives", Light: Science & Applications 9, 105 (2020) (OLED efficiency rolls off at high luminance; micro-LED efficiency depends on chip size, reduced below 50 μm; mass-transfer yield and defect repair as largest challenges; OLED burn-in and lifetime): https://www.nature.com/articles/s41377-020-0341-9
JBD, Hummingbird MicroLED 0.13" display (VGA, 6,350 PPI, up to 10 million nits green, 60 mW typical): https://www.jb-display.com/product_des/1.html
JBD, Hummingbird I binocular polychrome optical module (a different product from the 0.13" panel; diffractive waveguides, 6,000 nits eye-brightness, 300 mW typical): https://www.jb-display.com/product_des/8.html
OmniVision, LCOS technology (LCoS microdisplays for AR and VR; up to 6 colour fields): https://www.ovt.com/technologies/lcos/
Even Realities, G1 product page (Micro LED display, green, 1,000 nits; measurement point not stated): https://www.evenrealities.com/g1
Apple, Apple Vision Pro technical specifications (micro-OLED, 23 million pixels): https://www.apple.com/apple-vision-pro/specs/