Technology

Disruptive display technology

Building on its technological IP, expertise and many years of experience in the high-power LED lighting market and production of CMOS image sensors, Plessey has developed an advanced gallium nitride (GaN)-on-silicon (Si) technology platform. This platform is now enabling innovations for the manufacture of microLED displays that will, in turn, be available to the emerging developers of disruptive applications in need of highly-efficient micro-displays.

Plessey’s LEDs are made from GaN-on-Si, enabling the creation of monolithic microLEDs – with multiple emitters on a single chip and multiple chips on 150, 200 and soon to be 300mm wafers. This unique approach brings several key advantages and solves the issues that have held back microLEDs from the mass market until now.

GaN-on-Silicon

Key technological advantages

Silicon substrate

GaN-on-Silicon technology offers larger wafer sizes, flatter wafer bow, better wavelength uniformity, and ease of substrate removal compared to conventional sapphire substrates. The ability to manufacture pixels on larger 200 mm or 300 mm wafer sizes will lead to a substantial reduction in manufacturing costs, higher yield and throughput, which are critical elements in a commoditised display market currently dominated by LCD and OLED technologies.

Monolithic process

Plessey’s monolithic process is the only viable approach towards manufacturing ultra-fine pitch pixels (< 5 µm) microdisplays, as conventional pick and place process is still plagued with yield issues and extremely challenging for pixel sizes less than 20 µm. Coupled with Plessey’s 200 mm epiwafer growth and wafer-level bonding technology on 200 mm CMOS backplanes, this results in an efficient and economically scalable manufacturing solution.

Expertise

Plessey has positioned itself as one of the world leaders in microLED technology. It has the technical expertise and a portfolio of patent-protected enabling technologies only available at Plessey that directly addresses the current challenges faced by microLEDs.

Enabling the future with microLEDs

The market

There is an enormous opportunity for microLEDs (micro-light-emitting diodes) to penetrate major display markets and replace incumbent LCD and OLED (organic light-emitting diode) technologies in a wide range of applications, from HDTVs to smartphones and wearables such as smartwatches, and virtual/augmented reality headsets.

MicroLEDs offer an emissive display technology that delivers high contrast, high speed, and wider viewing angles. MicroLEDs also offer the potential for significantly higher brightness and will offer this at significantly greater efficiency thus enabling power trade-offs, as well as enhanced robustness and longer lifetimes. They can also provide for a smaller form factor, key for numerous applications, for example, head-mounted displays, in contrast to reflective technologies that require a separate light source and complex and costly optics.

Micro-displays

Incumbent technologies

Incumbent micro-display technologies fall into two types: directly emissive or reflective. OLED technology is an example of a directly emissive display, it is not particularly efficient and does not offer high levels of brightness and is subject to burn in.

Products such as HUDs and pico projector devices are commonly based on reflective technologies, typically using LCOS (liquid crystal on silicon) or digital micro-mirror device (DMDs), which require a separate light source to generate the image in conjunction with the LCOS or mirror. This reflective type display, while also not particularly efficient, is also typically a bulky and complex optical solution that is not well suited to wearables such as VR or AR head-mounted applications.