Light Gets Lighter

The change from oil lamps to incandescent light bulbs a century ago led to social changes as significant as the Roaring Twenties, whose nightlife was made possible by reliable indoor lighting, and suburbs, to which you could get home at night only if you had electric headlights on your automobile. Expect more changes in the next two decades as new lighting technology replaces the familiar incandescent and fluorescent indoor lights.

The technology that appears most likely to take over indoor lighting is the lowly LED — the source of the little “on” lights on your computer or answering machine. LED stands for “light emitting diode,” and this name hints at how small and simple LEDs are compared to the bulbs and tubes that we are used to seeing as light sources.

Red LEDs have been around for almost half a century. As the technology has improved, yellow, green, blue, and white LEDs have been introduced. LEDs still have two disadvantages that still rule them out for most lighting applications. They are expensive — a typical ceiling light costs around $100 — and they are not the most efficient form of light, using more electricity than the fluorescent lights used in most commercial buildings and the mercury-vapor lights that light some streets at night. However, if trends continue, these barriers could be overcome in about 5 years.

In the meantime, expect to see more LEDs in specialized applications where their unique characteristics give them an advantage. For indicator lights and other small lights that use less than 5 watts, LEDs are already the only practical choice. The small size and light weight of LEDs are an advantage in any kind of mobile lighting; they are already commonplace in miniature flashlights, and you can expect to start seeing them in vehicles. LEDs are cooler than light bulbs, which is a special advantage in lights that are worn on the body. LEDs are already commonly used in headlamps that people wear on their heads for activities such as mining. LEDs are said to last 100,000 hours, 100 times as long as traditional lights, so you might want to use them in places where light bulbs are hard to replace.

LEDs are especially efficient for colored lights. Unlike other lights, LEDs can be designed to generate the narrow frequency bands of red, yellow, green, and blue colors. Previously, colored lights were created only by filtering, a process that wastes most of the energy of the generated light. LEDs are already widely used in traffic lights — those new, thinner traffic signals in which the green lights are slightly bluer than you’re used to seeing are LEDs. This year might also be the year in which LEDs go mainstream in Christmas lights. It is still hard to make especially bright LEDs, but a few years from now, performers could have cooler stages to perform on as hot colored stage lights are replaced by much cooler LEDs.

Eventually, LEDs will be a good choice for ordinary indoor lighting. For desk lights, table lamps, and ceiling lights. you can already buy LED light bulbs that replace conventional light bulbs. Really, though, the screw-in socket connectors and glass bulbs are overkill for LEDs. A small plug-style connection would suffice and would allow smaller, simpler lighting fixtures.

Chandeliers fell out of favor a century ago when light bulbs were introduced, but with LEDs, they could make a comeback. Like candles, LEDs are efficient in small sizes, so they can be arranged with several light sources spread out across an area. This would avoid the concentration of heat that is the limiting factor in the design of fixtures for light bulbs and tubes, and it produces a more gentle room illumination with less obvious shadows.

Farther in the future, LEDs could be arranged as video displays to provide room light in the form of a moving picture. For example, an entire ceiling could be covered with a video sky image that would light the room. Video and room lighting have always been separate technologies in the past, but with LEDs it’s possible they could be combined.

This superficial analysis barely hints at the changes that could result from a change in lighting. Some experts, for example, say the quality of white LED light is so much better than fluorescent light that the productivity of office workers and students could increase by 20 percent or more. Changes in lighting always lead to changes in graphic design and fashion design. And lighting is just one of hundreds of technological changes likely to reach us in the next few years. It isn’t always easy to see the future, but one thing we can say with confidence is that it will not merely be more of the same.

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