It has been nearly 120 years since Thomas Alva Edison and Joseph Wilson Swan established the Edison and Swan United Electrical Lighting Company, inventing and producing some of the world’s first carbon-filament vacuum incandescent lamps. And it was just a century ago that bare electric bulbs decorated the exterior of the Pan American Exposition in Buffalo, NY, amazing and delighting children and their parents alike.
Artificial lighting affects the lives of billions of people around the world each day and lamp manufacturers continue to introduce new products and technology at a pace which might surprise even Messrs. Edison and Swan, although incandescent lighting represents an ever-shrinking percentage of the overall market for lamp products. "Nearly everything new today [in lamps] requires either a ballast or a transformer," notes Edward Effron, specification marketing consultant for Philips Lighting in Los Angeles. According to industry statistics, fluorescent lighting alone accounts for more than 80% of the artificial lighting used in the United States today.
Among all electrically operated light sources, however, incandescent and halogen lamps remain the most popular for decorative lighting in addition to applications which demand excellent color rendering. The operating principle of these lamps is still one of the simplest. Unfortunately, these lamps typically have a poor efficacy, or lumen-per-watt (LPW) ratio, and a considerably shorter life span than other alternatives. Advances in reflector and filament design continue to improve these statistics and new lamps are more compact and efficient each year.
What’s Hot in Halogen
Halogen/IR lamp technology utilizes an infrared reflective coating on the tungsten halogen lamp capsule, which refocuses waste heat back onto the filament, resulting in higher light output without increasing lamp wattage. As compared against an older, 150W incandescent PAR-38 lamp, HIR 100W PAR-38s produce more light, last 50% longer, and use 33% less electricity. Several manufacturers have successfully applied this technology to other lamp types, including General Electric with the Quartzline™ family of T3 linear lamps, Philips Lighting’s Continuum™ series of MR-16 lamps, and just a few short months ago, Osram Sylvania introduced two new, long-life IR bi-pin low-voltage lamps at 37W and 50W.
"Why not just start from scratch using IR technology and design lamps that can be screwed into a good reflector and then replaced?" asks Andrew Powell of Los Angeles-based Lighting Design Alliance. "Many European fixture manufacturers design reflector systems for halogen ‘bud’ lamps which have a far better chance of being relamped correctly when they burn out, since they’re designed for only one type of lamp. Here in the US, for example, Hydrel Lighting makes a series of in-grade and flood fixtures with integral reflectors that offer much better glare control than you can get with a PAR lamp."
"I’d also like to see IR technology developed even further," agrees Stefan Graf of Michigan-based Illuminart, "perhaps to a wider variety of MR-16s, smaller PAR lamps, or even a selection of PAR-20, -30, and -38 lamps with a very wide flood optic in 60º, 80º, or 90º that can serve as an efficient replacement for R lamps. It would also be fun to be able to unscrew and replace the front lens on a PAR lamp to change the optics on the fly, or just the lamp capsule inside, although there would probably be concerns about handling the lamps and cleaning inside the reflectors in the long run."
Other halogen products introduced in 2001 include Osram Sylvania’s Capsylite® G9 halogen lamp, which measures only 2.1" by 0.5", and at 120V does not require the low-voltage transformer typical of lamps this size. "We are very excited about its potential," says Osram Sylvania halogen product manager Erich Bockley, "both in terms of new, small designer fixtures and for conventional fixtures." General Electric has launched a 24V series of products including MR-11, MR-16, bi-pin, and miniature lamps to take advantage of higher system wattage loads and reduce the anticipated effects of voltage drop caused by line loss in many comparable 12V systems.
In MR lamps, Ushio Lighting is producing an ultra-miniature MR-8 in both 20W and 35W at about the same diameter as a quarter, plus the Whitestar™, first in a series of full-spectrum MR-16 lamps at 4200K, with a CRI of 94. Featuring extremely low UV and IR output, this lamp is ideally suited for fine art and museum applications, jewelry and showcase lighting, or other projects requiring excellent color rendition. "Osram Sylvania is doing a great job with the Tru-Aim® MR-16s," notes Powell, "and they have a good-quality beam combined with a good life, but I’d like to see more manufacturers expand on what Ushio has done, by developing more 10,000-hour MR-16 options."
General Electric created a line-voltage MR-16 with a built-in transformer, retaining the 5,000-hour life of ConstantColor™ series lamps while offering the convenience and durability of a medium screw-base socket. Designed especially for retail display lighting as a long-life alternative to PAR-16, PAR-20, and R-20 lamps, the line-voltage MR-16 lamp also offers better beam control and compares favorably to typical 12V MR-16 fixtures by eliminating the need for a remote transformer, thus reducing size, weight, and cost.
The Fluorescent Factor
Mercury vapor, sodium vapor, and fluorescent lamps were introduced into the lighting market in the 1930s and of the three, fluorescent lighting was by far considered the most revolutionary, given its low energy consumption, extended life, and the ability to fine-tune color using different types of phosphors. Defined by the IESNA as "a low-pressure mercury electric-discharge lamp in which a fluorescent coating [phosphor] transforms some of the UV energy generated by the discharge into light," these three crucial qualities still characterize most fluorescent lamps. Coupled with vast improvements in ballast design, this technology continues to dominate the lighting industry.
"Perhaps the neatest thing Philips has done lately is the Alto™ universal T8," explains Effron, "which will last to its full rated life on any T8 ballast, including instant-start, rapid-start, programmed-start, and hybrids. We can simplify our ordering system and the customer receives a lamp that will burn longer." Typically, T8 lamps only last to their full rated life using rapid-start ballasts, which are less common than the instant-start variety, according to Philips.
General Electric and Osram Sylvania have also recently announced T8 lamp and ballast systems that offer increased lamp life and/or energy savings over previous products. Alone, General Electric’s T8 Watt-Miser® lamp offers the performance of a traditional 32W lamp using only 30W of electricity, but when combined with the GE Ultra Ballast, a four-lamp system saves up to 11W per fixture. An XL version of the Watt-Miser® is rated at 25,000 hours. Osram Sylvania’s Xtreme T8 system combines the Octron XPS® lamp and the Universal Voltage Quicktronic® programmed ballast to achieve an estimated energy savings of up to 19% and an average rated life of 30,000 hours. Not to be outdone, Ushio Lighting has released its own Ultra8™ fluorescent line in four color temperatures with a rated life of 30,000 hours as well.
T5 fluorescent lamps, with a typical LPW ratio exceeding 100, are among some of the most efficient linear fluorescent products on the market. At only 16mm wide, General Electric’s new Starcoat™ T5 lamp series is small in size without sacrificing lumen output and is offered in nine wattages including a high-output 80W lamp with an initial 7,000 lumens. Philips also expanded its existing Alto T5 series lamp family with an 80W high-output product as well, plus a 55W T5 circular high-output lamp designed for both decorative and architectural lighting fixtures. "The trend of many fixture manufacturers towards downsizing to T5 and even T2 is great," remarks Graf, "and I wouldn’t be surprised to see more compact fluorescent lamps replace metal-halide in the near future, too."
Easing Up on Energy
With the recent pressure to improve energy efficiency for both residential and commercial users, manufacturers have accelerated the release of many new compact fluorescent products, especially those designed to replace incandescent lamps. Osram Sylvania debuted a 15W, 20W, and 23W Soft White Dulux® EL Twist lamp at 10,000 hours rated life with a color temperature of 3000K, suitable for sconces, table lamps, or any lighting fixture that might use a 60W, 70W, or 90W incandescent lamp. At 2700K, the new PL-T CFL lamp by Philips is available in 18, 26, 32, and 42W versions, and with the four-pin base is fully dimmable. "Our extension of this product line," says Effron, "was particularly timely for residential use not only in California, but nationwide, given our current energy crisis."
Rated even longer at 12,000 hours, Ushio Lighting’s new Coillight™ compact fluorescent family of lamps ranges in size from 9W to 23W and also features a 2700K color temperature and a medium screw base for simple installation. GE recently unveiled an extensive product line of compact lamps including triple and quad biax in 15/18W up to 28/29W, 30W circular, and 39W 2D specialty CFLs, plus an entire series of 15/20W A-, R-, and globe-shape replacement lamps. All of these GE products have at least a 6,000-hour life and save a minimum of 45W as compared to an incandescent lamp of similar lumen output.
In the larger biax compact fluorescent lamp category, Philips debuted a relatively unique, high-output 80W PL-L lamp with a stunning 6,000-lumen output and a four-pin base compatible with pre-heat, rapid-start, electronic, and dimming ballasts. "This lamp makes it easy to address design applications that require more light output but aesthetically need a smaller lamp," says Barbara Rentschler, Philips fluorescent category leader.
On a slightly smaller scale, GE presented both a 57W and 70W high-output version of the biax lamp available in three color temperatures and a 12,000-hour rated life. For motion picture, photographic, and television applications, Osram Sylvania also manufactures a fully dimmable, 55W biax lamp in 3200K and 5600K color temperatures to balance with either halogen or daylight sources and reduce the need for external filtering or post-production work.
Make Room for Metal-Halide
Metal-halide lighting, in contrast to its early predecessor, mercury vapor, typically operates at a much higher starting voltage and offers considerably better color rendering as a result of the mix of metallic additives in the arc tube. Once relegated primarily to industrial uses, the arrival of low-wattage compact metal-halide lamps in the last 15 years has opened up the market for these lamps to commercial applications such as retailing, convention halls, and landscape lighting. "There is no doubt," says Graf, "that the introduction of the ceramic arc tube has completely changed our use of metal-halide lighting."
General Electric recently demonstrated another option in this category with its tiny 20W G8.5-base ConstantColor CMH™ lamp, which operates on a miniature electronic ballast and is aimed at delivering point source optics for small fixture designers such as track or decorative lighting products. "At these low wattages, I’m not sure we’re not better off sticking to halogen," admits Graf, "but certainly the smaller arc tube offers much better optical control." Powell concurs, adding, "I think the 39W compact metal-halide is a pretty good low end to this line of lamps. At 20W you’re down into the range where other lamps are still practical, but it may be useful in a really small track head."
On the other end of the scale, Philips recently introduced a 400W MasterColor™ Pulse Start lamp available in 4000K. "It’s still limited to base-up, but we’re working hard on both a 3000K and a universal version as well," says Effron. "Although we’re not quite ready for ‘shoe-box’ retail yet, we expect this will be a big market for Philips. Of course, as with all new lamp technologies, they’re only as good as the fixtures they go in."
"I’d like to see more work done with 4000K and even 5000K ceramics as well," comments Graf, "to use in retail, museums, and other design projects that require higher color versions." Parallel to Philips, GE also extended its line of ConstantColor CMH lamps to include both 250W and 400W with a stated CRI as high as 94, plus an energy-saving Watt-Miser™ 360W replacement for its standard Pulse Start 400W lamp, rated at 65 CRI and 20,000 hours of life. Finally, General Electric expanded the PulseArc™ product line with 320W, 350W, and 750W lamps designed to extend lamp life up to an additional 10,000 hours and save electricity in combination with GE ballasts.
In addition to its own range of Tru-Color Metalarc® ceramic metal-halide lamps from 39W to 250W, Osram Sylvania is now shipping competitive versions of the higher-wattage metal-halide lamps as well, including 320W and 350W Pulse Start lamps, a 360W retrofit for standard 400W lamps, and last but not least, the 1,000W Metalarc® and Super Metalarc® lamps rated at 18,000 hours average life, almost 50% higher than similar lamps. For special applications, Ushio recently announced its new Colorlite™ high-wattage 400W and 1,000W metal-halide lamps, available in four highly saturated colors, no external color filter required.
Even conventional roadway and parking lot lighting techniques which use high-pressure sodium lamps have not been overlooked as possible areas of technical improvement by the major lamp manufacturers. A few months ago, Osram Sylvania extended the Lumalux® product line with a standby option that provides instant restrike capability following a power interruption, rated at 40,000 hours. Designed for applications which require the safety and security of continuous lighting, these lamps are a direct replacement for standard HPS lamps in equivalent wattages. In a similar fashion, Philips announced its own HPS direct replacement product with a CRI of 90, an outstanding improvement over the typically dull yellow color of most HPS lamps. Dubbed the MasterColor™ HPS-Retro White lamp, it’s available in both 250W and 400W and does not require periodic shut-off like most metal-halide lamps.
The Wrap-Up
Despite these innovations and continuous advances in existing incandescent, halogen, linear and compact fluorescent, metal-halide, and high pressure sodium fabrication methods, lamp manufacturers are speeding along a parallel track to develop the next generation of lamp technology. Organic light emitting diodes [OLED], high-brightness RF electrodeless sources, and LED chips are some of the newest and most exciting areas of research in lighting, with the promise of low energy consumption, rated life in excess of 100,000 hours, and extremely low heat.
"All things considered," concludes Graf, "I would encourage lamp companies to just keep doing what they’re already doing quite well—making lamps that last longer, have better color, and are more energy efficient."