First consumer microLED displays are just a start

The first microLED displays are now available. Is this the beginning of a tidal wave that could threaten OLEDs? – An article written by Eric H. Virey, principal analyst at Yole Group for Electronic Products.

MicroLED is a display technology in which each red, green and blue sub-pixel is an independently controllable light source: a tiny LED chip, typically less than 50 µm. Just like OLEDs, microLED displays are self-emissive. This means they retain all the benefits of OLEDs, such as high contrast, high speed and wide viewing angles. But their unique characteristics should allow an improvement in most performance metrics, including color depth and purity, contrast, brightness, power consumption, lifetime, environmental stability and ruggedness.

Unlike OLEDs, which require some encapsulation to protect fragile organic materials from oxygen and moisture, microLEDs are built from very stable materials and do not require any protection. This confers the ability to build bezel-free modules, or “tiles,” which can then be seamlessly assembled into a continuous display of virtually any size and shape.

No other display technology enables these bezel-free modules. LCDs require edge seals to contain the liquid crystals and OLED encapsulation, and to be effective, they must cover the full organic stack and extend by at least a few hundred microns beyond the edge of the pixels. This characteristic is already leveraged by Samsung in its 89-inch TV, using a 7 × 7 array of 12.7-inch tiles. The company has shown many other sizes, including a 76-inch TV, 6 × 6 array; a 101-inch TV, 8 × 8 array; and a 114-inch TV, 9 × 9 array.

Because microLEDs are so bright compared with OLEDs, the emitting area required for a given display brightness is much smaller. This enables very high aperture ratios (the ratio of the pixel to emitter area). This favors contrast for all displays but is especially beneficial for transparent displays. To deliver a clear, high-contrast image, transparent displays must also be extremely bright, another characteristic that favors microLEDs over OLEDs. Transparency is desirable in a variety of applications, such as retail, public information displays and automotive.

The combination of small emitter and encapsulation-free architecture enables another unique category: stretchable displays. Stretchability is hard to achieve with displays.

One promising avenue is to combine small, rigid islands containing the emitter and driving circuit with stretchable conductor lines. Because the ratio of the rigid versus stretchable area dictates how stretchable the whole display is, microLEDs offer an advantage. Stretchability enables freeform displays, which are flexible along any axis and conformable to any complex shape. Those could be integrated into fabrics. For automotive, as an example, they could enable complex-shaped designs and, when combined with actuators, replace physical buttons.

Finally, microLED technology could allow the integration of sensors and circuits, enabling thin displays with embedded sensing capabilities, such as fingerprint, in-display camera, touch function, gesture control and more…

… Read the full article here.