Shotton says the efficiency of the lights has been steadily improving in recent months. The goal is 50 lumens per watt for the first products and 75 lumens per watt by next year, which is comparable to many other LEDs. The best LEDs today get over 200 lumens per watt.
Printing with inks composed of tiny working LEDs produces much brighter light than depositing powders or thin films of electroluminescent material, two approaches that are already used to make flat night-lights and the greenish backlights on digital watches, and more recently to illuminate billboards with a white backlight.
Raghu Das, CEO of IDTechEx, a research firm that specializes in printed electronics, says printed-ink lights could be cheaper than the organic-LED (OLED) lights that have started to come on the market. OLED lights are expensive (one desk lamp costs nearly $6,000), and they have to be sealed inside rigid glass to protect the organic molecules from air and water.
The new design also makes the bulky heat sinks used on conventional LED lights unnecessary. Since the tiny LEDs are thinly and evenly distributed, the lights don’t get hot, Shotton says. The advantage of not having a heat sink is, however, offset by the fact that the LEDs require a substantial power source. To incorporate this power source, the company’s first light fixture will have to be two inches thick, even though the light-emitting surface is thin and flexible.