A BRIGHTER FUTURE:
Developing LEDs as a Lighting Source

November 26, 1997

The green light has been given to research and development on the use of highly-energy-efficient, durable, and long-lasting light-emitting diodes (LEDs) as lighting apparatuses to replace fluorescent lamps. If successfully developed, LED lights are expected to consume only one-eighth the power of incandescent lights and less than half the power of fluorescent lights. LEDs could be extremely effective in the reduction of carbon dioxide emissions, a major culprit linked to global warming. Researchers aim to have LED lighting in general use early in the coming century.

LED Lighting by 2005
LEDs are high-performance luminescent elements made from compound semiconductors. They boast greater efficiency than incandescent or fluorescent lamps in converting electricity into light. And small power consumption is but one of LED lighting's claims to fame. Other LED benefits include a life span 50 to 100 times longer than that of incandescent or fluorescent light sources, their compact and lightweight qualities, and an extremely quick response time to begin providing illumination when power is applied and stop providing illumination when power is removed.

Red- and green-colored LEDs emitting long-wavelength light are already widely used in automobile tail lamps, roadside traffic-information and other display boards, and many other applications. General lighting to illuminate larger spaces, however, requires diodes that emit short-wavelength light toward the ultraviolet region of the visible spectrum. This has so far proved difficult.

The Ministry of International Trade and Industry will form a team in fiscal 1998 (April 1998 to March 1999) composed of researchers from electrical appliance manufacturers, semiconductor manufacturers, and universities to start development of a compound semiconductor capable of emitting light toward the ultraviolet range. Research is scheduled to focus on investigation of compound semiconductors as luminescent material and into which materials provide the best hope for successfully bringing LEDs into practical use for general lighting. Research activities will be divided into technical issues involving the light source and the electrode materials. Successful development of this new kind of LED will enable its use as a replacement lighting source, either unaltered or injected into an incandescent- or fluorescent-light tube to produce white light. MITI intends to invest 5 billion yen (40 million dollars at 125 yen to the dollar) over five years in this project, with the goal being the practical use of LED general lighting by 2005.

Major Energy Savings
Using LEDs as general lighting apparatuses, if feasible, will enable significant reductions in power consumption. Preliminary calculations performed by MITI on lighting-based energy consumption show that Japan curre ntly consumes 47.8 billion kilowatt hours of light on an annual basis, assuming five hours a day of lighting by incandescent light bulbs or fluorescent lights. According to one projection, if general lighting apparatuses using LEDs are successfully developed and replace 50% of incandescent and 10% of fluorescent lights, overall annual usage would drop to 24.9 billion kilowatt hours--a 48% savings in energy consumption. Converted into units of crude oil, this would mean an annual savings of an equivalent of 6 million kiloliters of oil.

Further application of LED lighting is expected to encompass audio equipment, copy machines, neon signs, traffic signals, and more, for total annual energy savings equivalent to an estimated 10 million kiloliters of crude oil. That amount of savings is equal to the energy produced by five 1.35-million-kilowatt nuclear power plants. Curtailed power consumption of this magnitude will benefit everybody, reducing carbon dioxide emissions tied to global warming and saving consumers money on their electric bills.

Ministry of Foreign Affairs

Japan Information Network