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Some will argue that although these little lights, that were once inadequate for anything other than indicator applications, still lack the power necessary for full sign illumination. There are those in the one camp that believe that the success of LEDs will depend on how well LEDs can imitate neon's shape-shifting and lumen output capabilities for signage applications.

A little LED lesson
This LED series will offer some background into the development of LEDs along with some prognosis for the future. More technical information will be provided as this series progresses, but for now, just a quick note about LEDs.

One of the reasons that the lamps in your home probably have incandescent or fluorescent bulbs rather than LEDs is because incandescents and fluorescents can generate more visible light per watt than an equivalent LED.

LEDs are basically semiconductor devices that convert electrical energy into a distinct color of light. The original gallium arsenide red LED was invented in the 1960s. After the red LED came different colors such as amber and green. In the early 90's came the development of high-brightness LEDs, which created performance increases that allowed LEDs to mature from indicator lights to sources of illumination.

LED technology has the capacity to produce a more desired effect when used in specialty projects such as brake and taillights, display panels, industrial controls, and traffic signals, and is more energy efficient than incandescent lighting. In fact, as a side note, over one-third of all vehicle third brake lights are red LED clusters. Many carmakers use LEDs because the third brake light is often inaccessible and replacement is difficult.

LEDs offer the advantage of a fast strike/re-strike time, compact size and ease of dimming and control. Having already established itself in exit sign and traffic signal applications, LEDs are now entering markets once considered out of reach for such a physically small technology. Engaged in architectural and landscape illumination, cove lighting and wall washing, LEDs are finally carving new paths into areas once dominated by neon.

LEDs also offer advantages over traditional lighting sources that are not always readily apparent. "Unlike neon, incandescent or fluorescent light sources, LEDs are compact devices that have no filaments to break, no moving parts and no glass components of any kind", states Mike DeMarco, Tetra Product Manager for GELcore. "In addition to being virtually unbreakable, LEDs are low-voltage devices that generate very little heat, contain no mercury and emit a specific wavelength of light that can match the same color of the sign face material."

GELcore's GE Tetra LED system boasts that it is 80% more energy efficient than typical neon channel letter systems. "The inherent benefits of LEDs allow both sign companies and end users to significantly reduce sign installation costs, energy consumption and maintenance costs", says DeMarco.

Applications for channel letter illumination
The production, distribution and installation of channel letters are lucrative segments of the sign industry. That is all the more reason why it is important to carefully consider the alternatives available for the light source of channel letters.

It is important that when considering the available illumination choices, that the entire system of channel letters is kept in mind. All of the components such as the power supply, light source, face and backing materials and every other element involved must be coordinated for long-term satisfaction. If you change one variable, some unintended results may occur so it is wise to invest the time to determine what will work best for each project.

The energy savings, ease of installation, and other economical factors should not be overlooked. Maintenance and other factors that affect the application's lifetime cost may cause problems down the road so it is wise to consider the entire assembly as a whole when designing or installing a system.

As an example, a light source change from a clear neon to red LEDs might require a change of front face color in order to diffuse the LEDs' light source characteristics. There may be a need to substitute a transformer which might affect the letter's geometry and minimize prospects of capacitive effects common in high-frequency power supplies.

All of these variables should be considered when deciding to light up channel letters with LEDs instead of neon.

"We've seen two main challenges over the last couple of years. The first has been - how quickly can we educate the growing customer demand on the benefits of the LED system?" notes DeMarco. "Not only did we need to teach our customers the basics of LED technology and how the Tetra system compares to neon in a channel letter application, but we also needed to provide a thorough understanding of the many ways the LED system adds value to a sign company other than providing a great looking sign"

"The second challenge GELcore faced late last year was a result of our own success in the marketplace. As with all new technology solutions entering an established market, it takes some time to work out the delicate balance between supply and demand. We needed to be extremely flexible during this period when the market underwent the process of awareness, education, acceptance and adoption of our Tetra LED system as a replacement for neon." As DeMarco points out, the popularity of LEDs as used in channel letter illumination increases as more of its proof of performance is seen.

Currently available in red, red-orange, amber, blue, cyan, and green, LED channel lighting systems offer conveniences that will only grow in time. Although LED devices can't always compete with neon in the general sign market in terms of lumen output per linear foot for direct light applications, they can be competitive in certain types of signs and displays like channel lettering.

The future
Many companies now such as Permlight, Sloan, GELcore, ElectraLED and others offer LED lighting specifically tailored for channel-letter applications. The future for LEDs is wide open and channel letter illumination is just one of the areas where LEDs are beginning to really shine.

"The demand for LED lighting in channel letter applications is clearly growing and will continue to grow as LED system companies expand their LED product offering to include white", says DeMarco. "Generally speaking, white LED technology is not as developed as are saturated color LEDs. Although, white LEDs are currently being used in channel letters and other backlit sign applications, mainstream adoption will require improvement in both performance and cost of white LED technology. As we continue to improve the performance of white LEDs, there will be an increasing number of signage applications that make sense along the way, including medium and large backlit signs."

Storage, installation and care of LED products for channel letter illumination are getting easier as well. Some manufacturers are now shipping their channel letter product in reels, allowing the strips to be cut to size on location. These LED strips can be used in a wide variety of sign script fonts and they allow for a more efficient installation process.

As DeMarco states, "The market for LED systems in channel letter applications is clearly in the growth stage, but has become more established and consistent over time. This has made it easier for LED companies to anticipate demand and plan for future growth."

Exciting though these new capabilities and applications may be, it could still be several years before LEDs even threaten to replace neon lighting. The fact remains, though, that the technology continues to progress at a rapid pace that could soon make it more competitive in the not-so-distant future.