Tuesday, 03 Jan 2017 15:38 GMT

A Bright Future

LEDs have displaced conventional sources of illumination and have the potential to deliver even more disruptive developments. That may be a good thing, says Mark Godden

Signs of light

Who can say when LEDs first made a commercial impression on the signing and allied industries? ‘Moving message’ signs were arguably there when the lights came on and were among the first devices to demonstrate a practical application in a sign related area for LEDs. Moving message signs were, and still are, used as proxy for directory signing and even positioned to be in the vanguard of signing that could claim the merits of animation—excuse me, neon, we know you were first.

Moving messages’ revolution was delivered at the time by innovations like mixing basic red and green colours to get an orange-hello rendering. Two rows of type or more expanded the repertoire of the sign further and to this day the technology still has a seat at the table where there is a need to promote, direct, and inform, and the message needs to be legible and grab attention.


Moving message signs direct and inform




One sign-led innovation in LEDs that is lost to the winds (unless you come out of the woodwork and tell us what you are up to now) involved something utterly mesmerising at the time it was first seen back in the late eighties. It first saw the light of day at what was probably Sign UK back then. The ‘sign’ itself looked like an array, more a row actually, of LEDs stacked in a vertical line, one LED on top of the other so as to produce a strip about a metre long.

Upon approaching this vertical strip of light, each of the LEDs comprising it would go into seemingly random spasms of incomprehensible flashing. Stare as you might it just made no sense at all to look at—its purpose simply could not be ascertained and even defied conjecture. Upon turning away from the sign though, everything became vividly clear.

When the viewer’s attention turned away from the flashing strip and onto something else, persistence of vision would actually ‘paint’ a logo on the viewer’s retinas. Burger King, for example, thus appearing to the eye as though a physical sign was there in the thin air to the left or right of the flashing strip. The vision of the sign soon faded, but the memory remained.

Once the exhibition audience ‘got it’ they consciously tried to invoke the display in thin air. This gave rise to a spectacle not seen since at a sign show—an aisle full of people staring at a strip of LEDs and violently whipping their heads from side to side.

In the beginning

How did the industry’s interest in LEDs come to pass? LEDs were theorised and technically invented in the 1920s but it was not until the 60s that they found practical and commercial application.


LEDs found commercial application in the 1960s




Today, LEDs are ubiquitous. They have chased incandescent and other light sources out of vast areas of popular application and established numerous niche uses that are simply not practical or technically possible with other lamps.

First to feel looming obsolescence were indicator and tell-tale lights in instrumentation and electronic hardware. In mission critical applications, looking at an old fashioned indicator lamp that was saying nothing and wondering if it had gone was replaced with the near certainty that, if the LED was not saying anything, carry on. 

Now, even environmental lighting is being overtaken by LED driven events too, as more compact and ever more energy-efficient LEDs sweep aside everything hot and glowing in their path. Street lighting has made the journey. Intelligent lamp heads even have position aware smarts that turn on the lamp to suit local conditions and they can be programmed from anywhere there is an internet connection.

In a domestic setting, LED lamps are taking the fight to a front that glowing, hot glass envelopes cannot win.

Energy efficiency is winning the war for LEDs. Mood lighting—LEDs. Security lighting—LEDs. Ambient lighting—LEDs. We are surrounded by this technology and the light it admits is not going away. And it is far from done in terms of development.

LEDs are far from done in terms of further development”


More exotic variations on LEDs’ theme are also on the way. More applications will be explored. There is little doubt that the future belongs to LEDs and, outside decorative and nostalgic areas of application, little appetite or application will exist in the mainstream for conventional light sources.

LEDs have found many areas of application in the sign and allied industries. They are used as a light source. And they now power the hardware that cures the inks we print. They also enable the delivery of huge displays to the outdoor advertising industry. LEDs are no longer exotic and expensive—off the shelf signing, admittedly with a dubious reliability record, is available from the very far east for little money.

To understand why LEDs have swept opposition aside, it helps to understand the resistance they met. At one time, for example, the most popular source of illumination for exterior signs was the humble fluorescent tube, or, more to the point, vast arrays of them.

Tubes pump out the light, no doubt about it. Deploying them though was not the simplest of affairs. The interior of a sign illuminated by an array of tubes was the proverbial rats nest of wiring and hardware needed to suspend and power the tubes. The tubes required that the panel they were illuminating be stood off by some distance so as to avoid very unsightly hot spots in the illuminated panel. It gets worse.

Most tube-lit signing installations looked pretty good on day one, but, as the tubes degraded so the sign followed them into dark. Patchy illumination, flickering, and reluctant starts all spelled trouble. The remedy involved opening the whole sign, and, usually replacing all the tubes so as to maintain even illumination. Easier said than done in some cases where access was an issue.

Today’s story sees any of a number of chained LED lamps installed in boxes of similar design. Rather though than forcing stubbornly unbending tubes of an equally stubborn fixed length into an available space, LEDs can be put anywhere there is a few square inches of available real-estate. Hook up, switch on, and what you have is a bright and very reliable lit sign. It does not mind the cold. It is easier to transport and install, and it is likely to stay looking good much longer.

Move over neon

LEDs had neon in their beady-eyed sights virtually from the off. Offering the promise of a compact, energy-efficient light source, neon’s fragile nature and its highly specialist fabrication certainly showed its vulnerabilities once LEDs’ promise was understood.

Neon though, is a tough customer to beat. Numerous very credible alternatives have been proposed since the 1980s, but none really had the power to replace neon.

Neon is a tough customer to beat”


Arguably, the first application for neon to fall to LEDs’ assault was internal illumination for channel lettering. In order to get light to the extreme corners of, for example, a one metre tall Helvetica letter, neon tubing would be bent into something approximating the shape of the letter and installed within it. The craft and cost involved can only be imagined. And it was the province of a relatively exclusive band of companies with the skills and technical resources to do the job. LEDs changed that.

Installation of a chain of LEDs into the same letter is little different to that required of a very basic sign case. With nothing more challenging to bend than the wire connecting the LEDs, and nothing as remotely fragile as glass tube to handle, small sign installations fell to LEDs’ obvious attractions. It was not long before the same thing was happening at scale.

O Factoid: We had to wait until the 1970s for a blue LED and for another ten years or more until it was in practical use. O


Displacing ‘raw neon’ has been a more difficult undertaking and, truth be told, it has not really happened and probably never will. Not that it matters. The appetite for raw neon has been replaced with technologies that present outwardly something that is to many eyes as attractive and which represents an advance taking the medium further. Among these, Neon Plus from The Sign Group is an exemplar of real brilliance.

Neon Plus probably started life as an attempt to ape neon, and it certainly succeeded in doing that. A pair of lay eyes that alights on a Neon Plus sign is not going to be able to tell the difference between it and neon, and probably will not appreciate it either. Neon Plus though lives up to the ‘Plus’ part of its own branding. It is taking illuminated signing further than neon. It does what neon does and then some.


Neon Plus takes LED lighting to entirely new areas of application




LEDs enable Neon Plus. They are safely tucked away in the innards of all Neon Plus signs, protected and housed by enclosures machined from blocks of specialist acrylic. Capped with other machined acrylic parts, Neon Plus is as robust as it is beautiful, and it is stunning in its effectiveness. It is a shame there is no measure of signness as such. If there were, Neon Plus would be setting benchmarks.

Neon Plus benefits from LEDs versatility in other ways beyond the stellar amount of lumens they pump out and the compact dimensions they assume. Neon Plus also uses basic theatrical control to take three-colour LEDs and to mix up the output so producing thousands of different colours. It is a very creative use of the medium.

Bigger and better

Essex-based ASG was a pioneer in the application of RGB LEDs in signing applications. Its massive installation announcing Fort Dunlop near Birmingham is a few years old now but is among the most notable exemplars of LED powered signing.

The first thing that impresses is the scale. It is a big, big sign. Each of the letters comprising the sign is mounted on an individual post and within the letter is an expertly designed and installed array of RGB LEDs. The wiring supporting all the letters terminates in a theatrical control system, so that the colours of the lettering can be changed at will. It is still regarded as a state of the art LED sign today having won the Sign Of The Year Award in 2006. If it were neon lit, it would not have achieved its next-generation reputation.

LEDs are very easy to handle whether the comparison is drawn with neon or with tubes. That has meant that small sign manufacturing operations have been able to embrace them and make use of the features and advantages they embody. So, from signs on the scale of ASG’s work at Fort Dunlop, all the way down to small fascia installations, it is LEDs that are there pumping out the light.


This impactful and large scale Fort Dunlop sign installed by ASG is RGB LED powered




Until some otherworldly medium that emits light from within its mass is developed and made commercially practical, LEDs are going to be the medium to which the industry turns for light. LEDs are widely available, but they come with a bit of a health warning.

Not all LEDs are created equal. As with many other things in life, you really do get what you pay for with LEDs and its worth spending that little bit more on them. What you will get if you do is one LED that is at least on nodding acquaintance with the next in the chain. Its colour and its output for a given input will be within acceptable limits. Rush for something that looks like an unbelievable bargain, and that may not be the case. You may have saved a few quid, but you will have thrown away one of the reasons you chose LEDs in the first place.

There are many places you can turn for LED lighting, among them, Perspex Distribution, which handle the Sloan LED range. This range supports broad application in signing and is well supported with the network’s technical backup too.


LEDs are widely available in all sorts of configurations




In addition, you will find on the shelves various means of handing all the light LEDs pump out. For all the attractions of LEDs, they usually need some sort of optical intervention to manage the light they admit. In sign terms, that indicates a diffuser of some design or other. Some have caps with a pattern embossed that spreads the light. Perspex Distribution also offers a custom fabricated panel that amounts to a ‘slab of light’ powered by LEDs.

LED light sheets take advantage of a lighting phenomenon which means that, if you introduce light into the mass of a sheet of material, via its edges, that light will bounce around inside the sheet between its two plane surfaces, until it encounters a discontinuity in or on either of the surfaces where it can get out. Perspex has made a very useful product found on that effect.

Perspex Distribution’s LED light sheet is made to customised dimensions and has features on its surface that help the LED generated light within get out of the sheet. So, from within a sheet that might only have a minimal thickness, even light is provided across its surface. It can even be bent extending its versatility even further.

In the versatility stakes, LEDs have an impressive lead. Look around a typical sign shop and you may find them providing the energy needed to cure the very ink you are printing.

The cure

When UV inkjet printers first appeared, metal halide lamps were pretty much the only game in town when it came to curing the ink the hardware printed. UV printers were hot news because they would print on a wide range of uncoated substrates, not nearly as hot as the lamps curing the ink though.

A typical metal halide lamp runs at anything up to around eight hundred degrees internally and a good deal of that is radiated and soaked out when they are turned on. Surrounding machinery, print-heads, and ink-train all get their share of the heat, and so does the media when it is under the curing blast.

Some media take violent exception to being fried by UV light and they protest by curling, smoking, alarmingly or, in very extreme cases, melting. Printers aim for the minimal residence time practical with the UV curing on the media so as to avoid those unwelcome effects, that strategy can also avoid complete curing too—another unwelcome problem.

LEDs’ intervention when it came was welcomed to say the least. LEDs emit light in spikey, narrow distributions. So, provided the photo-initiators in the ink are in tune with the lamp, curing is complete without the attendant problems of dealing with all that heat.

LEDs do not mind being turned on and off either, whereas old school curing lamps do. Given that something north of a kilowatt is needed to keep an old-school lamp burning and an LED rig is happy to sip about seventy-five watts, running costs have to be questioned. ‘Always on’ energy hogs are never going to win against something that can be turned on as needed and takes smaller mouthfuls to start with.


Mimaki has been a key pioneer when it comes to using LED UV curing for its print technology




LEDs have helped printer designers to manufacture much more efficient hardware that is much less demanding of its media. Chemists have rushed to the front line and developed miraculous brews that just work rather than work just, and it does rather look like the trajectory is toward an LED sun, increasing rapidly in power, setting on yet another displaced technology.

One of LEDs’ most spectacular triumphs has to be that delivered to the out-of-home advertising industry in the shape of its massive and brilliantly coloured screens. Given what we know about LEDs progress generally, with price headed one way and utility another, the elephant in the room is, will LED screens ever displace large volumes of conventional external signing?

Developments will potentially displace whole swathes of the output the sign industry produces today. Maybe. Signs have an enduring appeal that is as much embodied in the medium as any message it conveys. Signs provide a colouration and emphasis that a display will never fully communicate. In signing terms, LEDs’ role is written. It is the preeminent means of illumination, it is only going to get better. Its versatility is beyond question.

Thanks to LEDs, illuminated signing is something practically any sign producer can make and make well. You could too.

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