Cheaper, brighter, leaner are the qualities driving light-emitting diode advances and no less than three companies have announced breakthroughs on Tuesday that further advance LEDs as our bright, lighting future.
Soraa, a Silicon Valley start-up, has emerged from stealth mode with a halogen-replacement product (pictured), North Carolina-based Cree says its new product delivers twice the lumens per dollar of previous-generation LEDs, while Britain’s Plessey says it has a new process that cuts costs by 80 per cent.
LEDs may be common now as backlights for TV screens and in many other consumer electronics products, but they still only occupy a small portion of the lighting industry.
They have been too expensive and have not generated enough light to date, plus they would have to make themselves backwards-compatible with our existing incandescent and fluorescent bulb holders to be attractive to most consumers.
But costs are coming down dramatically, light intensity is increasing and, combined with energy savings, payback times for LED investments are shortening to less than a year.
Soraa has an interesting background. Its Japanese co-founder Shuji Nakamura is known as the father of modern LED lighting, with his invention of the first high-brightness Gallium Nitride (GaN) LED. The Fremont company has received more than $100m in VC backing from Khosla Ventures, NEA and NGEN.
It is touting its ability to build a Gallium Nitride LED on top of a Gallium Nitride substrate with a new lamp built to the MR16 standard – a common multifaceted reflector currently powered by halogen.
Soraa says that GaN on GaN is superior to other technologies as it prevents a mismatch with the substrate’s lattice created when other materials such as silicon, sapphire or silicon carbide are used.
This helps it get over the problem of the “droop curve” – the falling off of performance and reliability in an LED as more and more current is driven through it. This has meant LEDs having to be run with limited current and at low temperatures.
Soraa’s GaN on GaN solution means a flatter droop curve and the ability to run an LED at a much higher current, with ten times the light density – and with room for further improvements.
“We call this LED 2.0,” Eric Kim, chief executive of Soraa, told me. Mr Kim is best known for developing Samsung’s global brand and running Intel’s Digital Home division.
Plessey announced the acquisition of CamGAN, a Cambridge University spin-out that grows GaN LEDs on large-area, standard, readily available silicon substrates. These cheaper materials and the ability to produce them in large sizes on automated semiconductor processing equipment will cut costs by 80 per cent compared to sapphire or silicon carbide processes, it said.
Plessey acknowledged there was a large lattice mismatch between GaN and silicon, but said its new process had overcome this problem.
Cree said samples were immediately available of its new XT-E LED, based on its improved silicon carbide process, delivering up to 148 lumens per watt, twice the lumens per dollar of its previous generation.
Mr Kim referred to his Intel experience as he said Soraa was taking the high road of going for the best possible performance:
“Our view is that the best way to achieve lowest cost is to improve performance and the perfect example of this is the semiconductor industry and Moore’s Law – it held true because of technological breakthroughs that at the same time reduced cost.”
Without providing a price, he said the MR16 would pay for itself in less than a year through energy savings. It will be aimed at commercial customers rather than consumers.
LEDs currently have less than 5 per cent of the global lighting market, but this is expected to grow to more than 25 per cent by 2015 and the majority of the market by 2020, according to Veeco, an equipment supplier to the LED industry.