Illumination: Optimizing LEDs for signage

by all | 30 March 2016 2:45 pm

Photo courtesy US LED

Photo courtesy US LED

By Peter Saunders
Light-emitting diodes (LEDs) are a household name today, with a growing number of general illumination applications in residential buildings and elsewhere, but only after enjoying a longer period of research and development (R&D) specific to the sign industry, along with long-term real-world use.

Since the early 2000s, when LEDs were a relatively unproven method of illuminating signs, the technology has come a long way in matching and improving upon the performance of neon and fluorescent tubing. Yet, there is also still more work to be done, with much of the sign industry yet untouched by LEDs.

The LED advantage
Perhaps the most well-known benefit of LEDs over traditional means of sign illumination is their environmentally friendlier energy efficiency, but they also offer other benefits. As solid-state lighting (SSL) components, for example, they are much more difficult to break during freight and handling than other bulbs, making for easier installations and maintenance. They also exhibit more consistent light.

LEDs were given a new market advantage in the sign industry after Underwriters Laboratories (UL) revised UL 2161, Standard for Neon Transformers and Power Supplies, in 2000 with new requirements for secondary ground fault protection (SGFP) to reduce fire hazards associated with neon signs. The ease of implementation for LEDs was made all the clearer by comparison.

Another step forward for the sign industry was the development of white LEDs.

“Red, green and blue (RGB) LEDs worked fine, but after white LEDs came into the market, they became brighter and prices went down,” says Carlos Vilanova, owner of Global Lux in Boucherville, Que., who had previously worked in the neon industry. “Today, there are so many competitors in the LED market. It’s been important to think outside the box to continue to make these products easier to use.”

Early improvements
The dynamics of the market in recent years can be seen in the evolution of US LED. Sign business veteran Ron Farmer founded the company in 2001 specifically to adapt LED technology for the needs of his industry.

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“Ron saw what was out there at the time wasn’t sufficient,” says the company’s director of sales for Canada, Luc Laliberté, based in Laval, Que. “With his background as a signmaker,
he saw the opportunity to save time both in the shop and in the field through reduction of breakage and the need for maintenance. He looked for the best LEDs available and worked with an engineering firm to ensure the reliability and durability of their products.”

The process of adaptation involved not only the LEDs themselves, but also the packaging that would make them more useful for both signmakers and installers. As the quality of the packaging improved, the expected lifetime of the LEDs grew from 50,000 hours to more than 90,000 hours.

By way of example, US LED’s patented quick-connect systems eliminated the need for ‘bolt-on’ connectors and wire nuts, which had previously represented a common point of failure.

“Over time, systems have been redesigned,” says Laliberté, “to the point where now a standard-depth, 381-mm (15-in.) stroke channel letter can be illuminated by just one row of LED modules, which was not even dreamed of a couple of years ago. There are also LED modules for cabinet signs that can be placed on 610-mm (24-in.) centres just 203 mm (8 in.) from the face—or on 508-mm (20-in.) centres at 152 mm (6 in.) from the face. This is all due to huge improvements in lenses. And with prices dropping with each improvement, there is little reason to use fluorescent lighting for these types of signs at this point.”

When LEDs first reached sign shops, they were most suitable for use inside channel letters. Photo courtesy SloanLED

When LEDs first reached sign shops, they were most suitable for use inside channel letters.
Photo courtesy SloanLED

Increasing versatility
With such developments, LEDs have also become practical for more types of signs today than they were in the early 2000s.

“LEDs are unidirectional, so when they first reached the sign industry, they were most suitable inside channel letters, where you only need lighting in one direction,” says Mike Bluhm, North American sales manager for SloanLED, which has served the lighting industry since the mid-1950s and specialized in LEDs since the early ’70s.

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As a design and engineering firm, SloanLED was also well-positioned to apply past lessons
to the customization of LED systems for the
sign industry.

“We came up with ‘poster box’ LEDs for wall signs, where side illumination is used to achieve even lighting within a very shallow profile,” says Bluhm. “We’ve also placed LEDs at angles to bounce their light off the sides of channel letters and used secondary optics to bend light in more visually appealing ways.”

“Each LED module and system has a different application, depending on sign depths and angles, and you have to educate people about how to use them, so as to optimize performance and reduce costs without sacrificing brightness and uniformity,” says Global Lux’s Vilanova. “You also need good wiring. Many manufacturers today provide high-
quality LEDs, but they all use different connectors.”

Also, as these systems have been introduced, signmakers have responded by specifying shallower profiles in the first place. With LED-based signs running cooler and taking up less space than their predecessors, they can be installed in places that would have been difficult to illuminate before.

“Perimeter lighting with LEDs allows for easier installation of accessibility signage versus conventional fluorescents,” says Bluhm.

The development of white LEDs was a major step forward for the sign industry.  Photo courtesy US LED

The development of white LEDs was a major step forward for the sign industry.
Photo courtesy US LED

New horizons
That said, some types of sign illumination have proven challenging or even impossible for LEDs to achieve, particularly at the larger, brighter end of the spectrum.

“We struggle to compete with the high-intensity discharge (HID) lighting that’s installed inside big pylon signs or blasts onto a billboard at night,” says Bluhm. “Those are cases where you need a lot of light across a lot of space.”

Similar problems are encountered across large flex-face signs that rely on tension bars running their entire length to help maintain their structural integrity.

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“Extrusions have been redesigned to bring the tension bars back a bit, but they still allow shadowing if you’re using LEDs,” says Bluhm. “They’re hard to light evenly.”

Where there is still much opportunity for LEDs, however, is in the replacement of fluorescent lighting, which is still common across the sign industry.

Improvements in lens design have helped LED modules create more even illumination across sign faces. Photo courtesy Global Lux

Improvements in lens design have helped LED modules create more even illumination across sign faces.
Photo courtesy Global Lux

“LEDs are still more expensive than fluorescent, but will shine brightly much longer,” says Bluhm. “A fluorescent lamp depreciates quickly from day one.”

With this in mind, he cites growing efforts to use LEDs to illuminate dye-sublimated fabric graphics in the retail sector, particularly to help reduce maintenance costs for those installed at hard-to-reach heights.

“The focus will be on replacing fluorescent lighting in sign boxes,” Global Lux’s Vilanova agrees. “There are only a few LED systems like that now and they’re still quite expensive, so there’s still a lot of market opportunity.”

With files from Global Lux, US LED and SloanLED. For more information, visit[1],[2] and[3].


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