Since white light is made up of a spectrum of different colours, the possibility of manipulating the light spectrum emitted by LED lights offers some of the most intriguing possibilities. “If we can control spectral distribution, this would give us a control knob that we have never had before,” says Dr Karlicek. For example, it should be possible to tune lights to give out a dose of near-violet light that would have antiseptic-like qualities, he adds. These could be used to keep countertops in kitchens clean, or to help maintain sanitary conditions in washrooms.
Spectral tuning could also make people more productive, Dr Karlicek believes. “There's certainly evidence that certain distributions can affect the ability of the brain to sleep or learn, for example,” he states. Although more research is needed, he suggests that it may be possible to design lamps that emit tailored light for students to use, to help them study more effectively, or ones that counter natural circadian rhythms to help night workers to stay awake.
Whilst these kinds of tricks mean the LED could have a bright future, there are other technologies hot on its heels. Recent research at the US government-owned Sandia National Laboratories showed that it is possible to generate white light that is pleasing to the human eye, by mixing the light from red, blue, green and yellow lasers, while a Illinois-based company called Eden Park Illuminations hopes to commercialise technology that involves sealing plasma behind glass in tiny aluminium foil micro-cavities, to produce ultra-thin, flexible lighting sheets.
But Dr Karlicek believes that LEDs are here to stay. “Plasmas, incandescents and fluorescents will go the way of the vacuum tube after the invention of the transistor,” he promises. “People still use vacuum tubes for some applications, and similarly incandescent bulbs may never go away completely. But it is not a question of if, but of when LED lighting will be the norm throughout the world.”
You may never look up at the ceiling in the same way again.
