Light and Lighting -- Make More Money

By Darek Johnson - Article from SignWeb.com

The light system -- LED or neon?

LEDs are solid-state devices that use very little electricity to create light. Search the Internet and trade magazines, and you'll find buckets of information comparing neon and LED lighting. You'll learn, for example, that red LEDs last longest. You'll also discover that neon wins over LEDs in single-lamp color choices, but when arrayed (in panels), RGB LEDs, with effectiveness similar to your home television, produce all colors.

LEDs (in select colors) can last up to 50,000 hours. You'll find them used singularly or in encapsulated groups (modules) of (generally) red, green and blue (RGB) that form the pixels for electronic digital signs (EDS).

General Electric's Nick Holonyak Jr. invented the first light-emitting diode (LED) in 1960. This unit produced a dim yellow light and lasted only a few hours. Today, LEDs, through an RGB-based arrayed system, offer a wide range of colors. Some opponents question LED manufacturers' lamp-life claims, but they aren't considering software-based intensity controls that sense ambient light and automatically adjust the system's electrical input accordingly.

Opponents say LEDs white light has limited uses, especially in the hues needed for areas in which humans interact. This is almost true. Sans phosphors, an LEDs' white light is blue-white, similar to that of brilliant moonlight. It lacks the reds and yellows that make human skin appear warm and cuddly. Phosphors fix this.

At LightFair 2003, Lumileds™ (San Jose, CA) announced its planned release of a warm-white, phosphor-treated version of its Luxeon high-brightness LED (HB LED). It has a correlating color temperature of 3,200K (the same as a standard, home, incandescent lamp) and outputs at 22 lumens.

Because it's a high-research technology, there's always more. For example, Color Kinetics Inc. (Boston) recently announced its Chromasic™ microchip system, which enables a controllable, four-component (LED) lamp to generate 64 billion color combinations "within the space of a pencil eraser."

Philadelphia's Strawberry Mansion Bridge, illuminated by Lightmark™ LED-based, solid-state lighting, was engineered and installed by TIR Systems Ltd. (Vancouver, British Columbia, Canada). TIR's software package allows city engineers, through an office modem, to create color-change programs for seasonal holidays, special events or sports teams' logos. The bridge won the Federal Highway Administration's 2002 Excellence in Highway Design Award. Photo credit: Lane Fike.

LED applications

The U.S. Dept. of Energy endorsed LEDs as part of its campaign to reduce U.S. energy use, and, in June 2002, the U.S. Secretary of Energy, Spencer Abraham, at the 13th Annual Energy Efficiency Forum in Washington, D.C. reported white LEDs as "a revolutionary technological innovation that promises to change the way we light our homes and businesses." His office reports that "the most advanced white LEDs," compared to incandescent lamps, are expected to provide energy savings of 90% by the year 2020.

One fact is certain -- many large companies are investing millions of dollars in LED lighting and related systems, thus even more improvements will surely follow. Applications multiply daily. For example:

*17,000 white Osram Sylvania (Danver, MA) LEDs illuminate the interior-dome text frieze of the Thomas Jefferson Memorial in Washington, D.C.

*The Suffolk County (New York) commissioners, looking at cost savings in power consumption (85% less than conventional lamps) and maintenance, have recommended retrofitting the county's traffic lights with LED fixtures. You'll find this LED traffic-light retrofitting pattern around the country and the world.

* Both LumiLEDs and Osram Opto Semiconductors (Munich, Germany) have displayed concept vehicles that are completely equipped (head, tail and interior) with high-brightness LEDs (HB-LEDs).

Auto manufacturers prize LEDs because they take more abuse than incandescent lamps. Even if you fumble and drop an LED, you can still install it. Plus, LED brake lights are safer because they illuminate two-tenths of a second faster than standard incandescents, giving those drivers that follow too closely an additional 10-15 ft. of stopping space.

Photo courtesy of ElectraLED (Clearwater, FL)

There's more. British Petroleum (BP)-Australia (Melbourne, Victoria) recently contracted with TIR Systems Ltd. (Vancouver, British Columbia, Canada) to provide its Lightmark™ LED-based, neon-replicating, solid-state lighting product for accenting the oil company's illuminated overhead canopies.

TIR also illuminated Philadelphia's Strawberry Mansion Bridge with solid-state LEDs (see page 73). An enchanting rehabilitation project, the bridge won the Federal Highway Administration's 2002 Excellence in Highway Design Award (historic preservation). Again, energy and maintenance (after all, bridges vibrate) savings were the rationale. Additionally, TIR provided a software package for the bridge's lighting system so that city engineers, through an office modem, can create color-change programs for seasonal holidays and special events.

Truth is, LEDs are hard to ignore. They are the subject of huge research projects (with huge budgets) conducted by such companies as Mitsubishi Diamond Vision (Lawrenceville, GA), Cree (Durham, NC), LEDtronics Inc. (Torrance, CA), Agilent Technologies (Palo Alto, CA), Citizen Electronics (Tokyo) OSRAM Opto Semiconductors, Panasonic, (Secaucus, NJ), Philips (the Netherlands), General Electric (Fairfield, CT), Gelcore (Valley View, OH) and ElectraLED (Clearwater, FL).

The antagonists

Curiously, LED usage encounters opponents in the sign industry, a field renowned for its innovative uses of light. Customarily, this opposition comes from the neon section, and comparisons focus on illuminating channel letters. Truth is, each case is different and, depending upon circumstances, one may perform better than the other.

Georges Claude first displayed his newly invented neon in 1910. You could see its American debut at a Los Angeles Packard dealership in 1923. In a sense, you could say that neon withstood the test of time because today's neon technology is remarkably similar to that of the 1930s.

A fair sign-industry analysis of LEDs vs. neon must examine not just channel letters, but every niche of the industry, including electronic digital signage, backlighting for directional and hazardous area signs and push-through letters, plus wayfinding and information systems. The analyst should further include places where neon isn't typically installed, such as short-return and smaller channel letters, uses in multi-layer shopping center signage, and ornamental and very small signs.

Comparisons must also consider the labor and overhead costs of establishing and operating a neon-signmaking shop.

You have to think of OSHA regulations when regarding neon. You also must consider intensified fire-department inspections, insurance costs and the higher-than-average wages of neon benders. In the final analysis, comparing handmade neon to high-tech lighting systems is like comparing homemade biscuits to Wonder® bread. Homemade biscuits aren't bad, but they're not easy to put on the plate.

Shown with the faces removed, this channel-letter set displays ElectraLED's (Clearwater, FL) 24V LED system. It includes a Nema 3R, wet-location power supply and pre-cut LED boards.

 

LEDs, the other white heat

LED opponents always reference the white-LED heat bugaboo. As mentioned above, one way to produce white light, from blue LEDs, is to first coat them with phosphors. As in other phosphor-based lighting systems (such as fluorescent lamps), adding phosphors allows the engineers to vary the white's hue (candlelight yellow) to moonlight blue.

Applied to LEDs, the phosphor coating (it includes a binder) tends to encapsulate, or at least layer, the lamp, causing it to retain heat. You also have to crank up the watts to maintain a light intensity comparable to other light sources. Therefore, applying coating is one method of converting the light emissions of blue or ultraviolet LEDs to white -- but the coating tends to heat the element. Engineers also create white light by blending RGB at higher than usual (heat-causing) currents.

All lamps produce self-destructing heat, but there are ways around this. With LEDs, one method is the previously mentioned software-based intensity controls. Another is a heatsink.

"Heatsink," a welder's and electronic designer's term, is the practice of positioning a heat-absorbing material between a heat-sensitive item and the heat source, to draw off the hotness. A ceramic coffee cup is an example; by absorbing and distributing the coffee's heat, it lessens the hotness reaching your fingers. With LEDs, a common practice is to build a direct-flow, aluminum heatsink into the lamp system, to pull the heat off the diode.