MicroLED

MicroLED (also written micro-LED, mLED, or µLED) is a flat-panel display technology in which each pixel, or each colour subpixel, is a microscopic inorganic light-emitting diode that emits its own light. Because the diodes are made from inorganic semiconductors, usually gallium nitride (GaN) and related III-nitride alloys, microLED is self-emissive like OLED but uses the same robust materials as conventional LED lighting. The technology spans two very different product classes: large direct-view video walls, and tiny near-eye microdisplays for augmented reality (AR) and, to a lesser extent, virtual reality (VR). In the XR context the microLED microdisplay is of most interest because it can reach brightness levels that no other current microdisplay technology matches, which suits it to see-through AR glasses used outdoors.

How it works

A microLED display is an array of inorganic LEDs in which each diode is on the order of a few micrometres across; pixel pitches in current AR microdisplays are around 2.5 to 4 micrometres, and individual emitters can be smaller than 5 micrometres. Each emitter is driven individually, so a pixel can be switched fully off to produce true black and a very high contrast ratio. Unlike a liquid crystal display, a microLED panel needs no backlight, and unlike OLED it uses inorganic rather than organic emitters, which gives it longer expected lifetime, higher achievable brightness, and resistance to the burn-in seen on organic panels. The inorganic diodes also switch in well under a nanosecond, far faster than LCD or OLED, which removes most motion blur and ghosting.

A full-colour display normally needs red, green, and blue subpixels. There are two broad ways to build the panel. In the pick-and-place or "mass transfer" approach, separately grown red, green, and blue LED dies are transferred onto a driver backplane; this is used for large video walls but is slow and yield-limited at small pixel sizes. In the monolithic approach used for near-eye microdisplays, an entire LED array is grown on one wafer and bonded to a silicon CMOS driver chip (a complementary metal-oxide-semiconductor integrated circuit), giving very high pixel density on a single small panel.

History

Inorganic semiconductor microLED technology originated in 2000 with the research group of Hongxing Jiang and Jingyu Lin, then at Kansas State University. Their paper "GaN microdisk light emitting diodes," by S. X. Jin, J. Li, J. Z. Li, J. Y. Lin and H. X. Jiang, was published in Applied Physics Letters in 2000 and reported InGaN/GaN microdisk LEDs about 12 micrometres in diameter, noting that the small devices showed enhanced quantum efficiency relative to broad-area LEDs. The same group, by then at Texas Tech University and working with the company III-N Technology, demonstrated the first high-resolution, video-capable InGaN microLED microdisplay in VGA (640x480) format in 2009, by actively driving the LED array with a CMOS integrated circuit.

Commercial direct-view products appeared in the late 2010s, including Sony's CLEDIS modular displays and Samsung's "The Wall," both built by tiling many small microLED panels into very large screens. Near-eye microLED microdisplays for AR were prototyped by several companies around 2019 and 2020, and the first consumer AR glasses using them shipped in 2024.

Why microLED suits AR

See-through AR glasses route the image from a tiny display through an optical waveguide into the eye. Waveguides, especially diffractive ones, are very inefficient: only a small fraction of the light that enters reaches the eye, because of etendue limits at the waveguide's small input area, the need to collimate the diffuse Lambertian output of an LED, and losses at the in-coupling and out-coupling gratings. To stay readable in daylight the display therefore has to be extremely bright at its source. Display analyst Karl Guttag has noted that microLED microdisplays are hundreds to more than a thousand times brighter than Micro-OLED microdisplays, which is the property that makes them attractive for outdoor AR despite their current colour limitations. Their self-emissive design also removes the separate illumination optics that a liquid crystal on silicon (LCOS) projector needs, allowing smaller and lower-power projection engines, an advantage Meta cited for its Orion prototype.

The red microLED problem

The main technical obstacle to full-colour microLED is red. Blue and green emitters are made efficiently from indium gallium nitride (InGaN), the same material family as standard LEDs, but pushing InGaN to red wavelengths requires high indium content that lowers efficiency, and the problem worsens as the diode shrinks because non-radiative recombination at the etched sidewalls dominates in tiny devices. Research has measured the external quantum efficiency of sub-5-micrometre red microLEDs as low as about 0.1 percent, far below blue and green, and reaching even a few percent at small sizes has been treated as a notable result. The alternative, aluminium gallium indium phosphide (AlGaInP) red, is efficient in larger LEDs but degrades severely at micrometre scale and uses a different material system, complicating monolithic integration. Because of this, many shipping AR glasses use single-colour (usually green) microLED panels, and full-colour microLED for glasses is still maturing.

Manufacturing challenges

Beyond red efficiency, microLED is hard to manufacture at scale. For large displays the mass-transfer step that moves millions of individual dies onto a backplane is slow and demands very high yield, because every defective or misplaced emitter is a visible dead pixel; transferring and reworking the LEDs for a single large screen can take many days. Monolithic microdisplays avoid the per-die transfer but still need uniform brightness across millions of micrometre-scale emitters, accurate bonding to the CMOS backplane, and a workable full-colour scheme. These difficulties, together with cost, were behind Apple's decision, reported in March 2024, to cancel its multi-year in-house project to build microLED displays (initially targeted at the Apple Watch), with the company concluding the technology was not yet economically viable and continuing to use OLED.

Companies and products

Several specialist firms make microLED microdisplays aimed at AR and other near-eye uses.

• JBD (Jade Bird Display), founded in 2015 in Shanghai with manufacturing in Hefei, makes monolithic microLED microdisplays using a hybrid integration process. Its production monochrome panel is a 0.13-inch VGA (640x480) display, and it has demonstrated higher-density platforms with pixel pitches around 2.5 micrometres. In December 2024 JBD announced a full-colour RGB microdisplay called Phoenix with a white-balanced brightness of about 2 million nits, using a stacked architecture, with mass production of customised units planned from the third quarter of 2025.
• Porotech, a Cambridge, UK company spun out of the University of Cambridge, uses a porous gallium nitride material it calls PoroGaN. Its DynamicPixelTuning technology, first shown in 2022, lets a single InGaN pixel emit across the visible spectrum, including native red, rather than relying on fixed red, green, and blue subpixels. Porotech has partnered with Foxconn, which announced plans to build a microdisplay fab based on Porotech's technology, and supplies porous GaN templates for InGaN red microLEDs.
• Plessey Semiconductors, based in Devon, UK, developed a monolithic GaN-on-silicon microLED process and in 2020 signed a long-term agreement to dedicate its manufacturing to Facebook (now Meta) for AR display development. In January 2025 Plessey and Meta announced what they called the world's brightest red microLED display for AR glasses, citing brightness up to 6,000,000 nits at a pixel pitch below 5 micrometres.
• Mojo Vision, a California company, originally built an AR smart contact lens around a tiny monochrome microLED. After halting the contact-lens project in early 2023 and laying off most of its staff, the company refocused entirely on microLED display development.

Use in AR and VR hardware

The first shipping consumer AR glasses built on microLED used JBD's monochrome green panels paired with waveguides. The Vuzix Z100, which began shipping in November 2024 at 499 US dollars, uses JBD's 0.13-inch 640x480 green microLED with a Vuzix waveguide. The Even Realities G1 likewise uses a green 640x480 JBD microLED with diffractive waveguides for a minimalist text-and-notification display. By the close of 2024, JBD reported that its microLED panels powered more than 30 announced AR smart glasses, including the Rokid Glasses, which began shipping in November 2025 with JBD monochrome green displays.

Meta's Orion prototype, shown in 2024, uses full-colour microLED projectors that beam an image into silicon carbide waveguides, giving a 70-degree field of view in a glasses form factor; Meta said the microLED projectors are smaller and more power efficient than the LCOS engines used in many smart glasses, although Orion's angular resolution is only about 13 pixels per degree and each unit costs on the order of 10,000 US dollars to build, so it is an internal development device rather than a product. By contrast, the consumer Meta Ray-Ban Display, announced in September 2025, uses an OmniVision LCOS microdisplay with a reflective geometric waveguide rather than microLED, illustrating that LCOS and Micro-OLED remain competitive in this market while full-colour microLED matures.

MicroLED is used much less in virtual reality than in AR. VR headsets are opaque and do not lose most of their light to a waveguide, so they do not need the extreme brightness that distinguishes microLED, and they require the large, dense, full-colour panels that microLED still struggles to produce affordably. As of 2026 mainstream high-end VR headsets such as the Apple Vision Pro use Micro-OLED rather than microLED, and microLED's primary XR role is in see-through AR microdisplays.

Comparison with other display technologies

Property	MicroLED	Micro-OLED / OLED	LCD / LCOS
Emission	Self-emissive, inorganic LED	Self-emissive, organic	Backlit (LCD) or reflective, needs separate light source (LCOS)
Peak brightness	Very high (microdisplays reported in the millions of nits)	Moderate; far dimmer than microLED at microdisplay scale	High for direct-view LCD; LCOS depends on its illuminator
Contrast / black level	True black, very high contrast	True black, very high contrast	Limited black level (LCD); depends on optics (LCOS)
Lifetime / burn-in	Long life, no organic burn-in	Shorter life, susceptible to burn-in	Long life (LCD)
Response time	Sub-nanosecond	Microseconds	Milliseconds (LCD)
Full colour at microdisplay scale	Difficult, red efficiency is the main obstacle	Mature	Mature
Manufacturing maturity	Emerging, costly mass transfer or monolithic yield issues	Mature	Mature