Household plastic light bulbs that promise long life and safety are coming to a living room near you.
Such bulbs, based on light-emitting diodes, are getting brighter and more flexible, opening new design possibilities for illumination.
LEDs emit light when low-power electric current passes through them. They emit very little radiant heat, which means lighting producers can do away with fragile, high-temperature glass bulbs. Plastic bulbs and housings are more durable and allow myriad shapes.
LED lights have been around several years but so far they mainly have found use in specialty installations, such as in casinos, museums, art displays and similar venues where artistic freedom is more important than cost. As their price declines and as consumers realize their benefits, LED lights promise to make a big impression in the general illumination market.
PolyBrite International Inc. is one company striving to develop household lights with plastic bulbs encasing LEDs. The Naperville, Ill., firm claims its bulbs are break resistant, use 90 percent less electrical power and can last up to 50,000 hours, or 10 times longer than a typical incandescent bulb.
Westinghouse Lighting Corp. has joined forces with PolyBrite to help bring the plastic/LED bulbs to the general illumination market.
That market is worth some $10 billion in U.S. sales annually, although LED lights now account for a very small share of the total, said Sandra Goeken, vice chairman of Goeken Group Corp., PolyBrite's parent company. Its founder, Jack Goeken, also founded the communications giant now known as MCI and the Airfone airplane-to-ground telephone network.
Westinghouse and PolyBrite currently are promoting Marquee 60 bulbs for commercial and institutional use. Early next year, they expect to launch bulbs aimed at the household market, said PolyBrite Chief Executive Officer and President Carl Scianna.
``This represents a real revolution in lighting,'' said G. Thomas Castino, retired CEO of Underwriters Laboratories Inc. of Northbrook, Ill. He became familiar with LED light research several years ago when UL and the American Lighting Association got together to examine emerging lighting technologies.
The new bulbs' safety features are especially useful in commercial and institutional applications, including hospitals, oil rigs, laboratories and other areas where flammable volatiles might be present, Castino said in a telephone interview.
PolyBrite's Marquee 60 bulbs provide as much light as a regular 15-watt incandescent bulb but at under 5 watts of power consumption. With a standard screw base that fits conventional incandescent sockets, the bulbs come in white, amber, red, green and blue. Westinghouse envisions they will be used initially in decorative and signage applications.
Many processes, many applications
The bulbs rely on plastics technology to enhance the LED light. Sciana said plastic bulbs can be made by blow molding, extrusion and injection molding - the Marquee bulbs are injection molded, mostly in China. Sciana and other officials declined to give much detail about the bulb, but the company's most recent patent filing lists ethylene/butene polymers and polypropylene among the materials used - specifically Exact and Achieve polymers made by ExxonMobil Chemical Co.
PolyBrite already has developed special bulbs for military applications. One application is for U.S. Navy submarines. Westinghouse recently announced submarines have tested and will adopt LED light collars to illuminate emergency air stations and escape hatches. The LED bulbs can withstand high pressure and other adverse undersea conditions. Other plastic/LED light products introduced by PolyBrite include airport safety vests and marshalling wands, and pet safety collars.
PolyBrite's use of LEDs in bulbs is engineering that relies on more than 40 years of advances, said Nick Holonyak, who made the first working LED in 1962 when he worked for General Electric Co. Now he's a professor of physics at University of Illinois at Urbana-Champaign.
``I'm happy to see [the plastic/ LED bulbs],'' Holonyak said. He added that PolyBrite is making the bulbs convenient by relying on conventional screw bases that fit incandescent sockets. ``At first, LEDs were scientific curiosities,'' related to semiconductors, he said.
Initially used only as indicator lights, LED applications have spread. For example, Holonyak said LEDs are being adopted for vehicle brake lights.
Plastic lenses and housings are common among the several firms developing LED lighting, according to Steve Landau, a spokesman for Lumileds Lighting LLC, a San Jose, Calif., company that bills itself as the leading LED manufacturer in the world. Not all firms use PolyBrite's approach of retrofit bulbs for incandescent sockets. Since LEDs are compact, their design can comprise a light and fixture smaller than for an incandescent bulb and with different electrical connectors, Landau said.
Lumileds customers include Color Kinetics Inc. and OptiLED.
Color Kinetics of Boston specializes in decorative accents in large installations like hotels, casinos and corporate offices. Spokesman Kevin Dowling said his firm relies heavily on plastics for housings and lenses. The firm seeks properties such as ultraviolet-light stability for outdoor use, translucency for light diffusion, optical clarity, strength and resilience.
Color Kinetics specifies plastic components, which are made in China by contract manufacturers. Its main plastics are polycarbonate, ABS, acrylics, polybutylene terephthalate, thermoplastic elastomers and ethylene/propylene diene monomer.
For high-wattage LEDs, heat must be conducted out the back of the LED, Dowling said. So far the firm has used aluminum and copper for heat transfer, but it would like to see a thermally conductive plastic take over that role, since it might be more cost-effective.
Irvine, Calif.-based OptiLED has been selling LED bulbs into the general retail market for more than two years. Its Festival bulbs, which are molded in China, fit standard incandescent sockets. The bulb is polycarbonate and smaller than a conventional glass bulb. OptiLED also is active in LED lights for landscaping, architectural, entertainment and designer installations.
With a list price of about $30 per bulb, Festival lights may be too expensive for consumers, said OptiLED Vice President Bruce Pelton. The bulbs come in sizes from one-half watt to 2 watts, giving illumination equivalent to incandescent bulbs rated at 20-40 watts.
``The retail channel doesn't understand the cost/benefit of LEDs,'' he said.
Sales so far have been concentrated among electrical contractors and operators of casinos, hotels and other institutions. For these customers, LEDs dramatically cut down on maintenance and utility costs. In large buildings, incandescent lighting contributes to the load on air conditioning systems.
Festival bulbs are rated for about 60,000 hours. In fact they last much longer, but their illumination output declines. At 60,000 hours they put out about 70 percent as much light as at the beginning of their life.
Sciana said most PolyBrite Marquee bulbs are made in China because that's where most incandescent bulbs are made. China provides a local source for components such as the screw base, he explained. PolyBrite also has some production in Italy and the United States. As volumes increase, he expects plastic/LED bulbs to be made in the United States. Because the bulbs are assembled by robots, countries with low labor costs do not have a natural economic advantage, he said.