LEDs and Building?
Compared to the last light+building show two years ago, this year’s show, held in Frankfurt, Germany, April 11-16, grew, having attracted more than 180,000 visitors (an 8% gain), who saw 2,177 exhibitors on 2.66 million sq. ft. of floorspace. These gigantic numbers justify labeling it the world‘s leading lighting show. Also, the central European location attracts exhibitors and customers from east and west – more than 43% of visitors came from abroad.
Finding sign-related new products in this mass was a challenge. However, the general lighting trend is that any product will sell, regardless of the facts, if it’s advertised either as CO2-saving or LED.
A German company advertised a vacuum incandescent lamp that would present “75% energy savings” (compared to a carbon-fiber lamp, I found out, even though they wouldn’t tell me), and its efficacy had been demonstrated for roughly a century. To demonstrate the “green movement,” Megaman (Neonlite Electronic & Lighting Ltd., (Hong Kong) is the parent company), which produces energy-saving lamps, now almost exclusively LED, created a rainforest atmosphere with palm trees and bird sounds.
A major LED-usage trend: directed outdoor lamps for street lighting and floodlights, which might be applied to lighting billboards. However, those I’ve seen employed LEDs with a very bad color-rendering index. The necessary heat management and data on long-term usage in warm-climate zones were missing. Yes, I did see LEDs with the water-cooling system at the Ceramtec booth.
Even if LEDs were shown everywhere in general lighting applications (where other lightsources were used before), the lighting-fixture company Zumtobel (headquartered in Dornbirn, Austria, with a Highland, NY, U.S. office) announced, according to their test results, LEDs aren’t yet suited to retrofit general fluorescent lighting, because of their color rendering and low efficiency; other lightsources were much better suited because they’re widely available at lower cost with better technical parameters.
Osram (Munich, Germany) claimed it has produced a white LED that has an efficiency of 150 lm/W (standard-production values are 50 to 60), and Cree reported a 160 lm/W LED. After having asked questions at both companies’ booths, I found both items are only in the laboratory-testing stage, and reliable datasheets or samples will be available in roughly four to six months, whereas production will begin in approximately a year.
However, Cree (Durham, NC) revealed its product will bear a color-rendering index of roughly 70, making it useful for general, low-quality, ambient lighting, but not for illuminating color prints or signs. Also, Cree representatives said its LMR-4 LED fixture with a built-in power supply isn’t yet suitable for outdoor (read: sign application) use.
But, my report wouldn’t be honest if I didn’t report what I consider good, reliable business ethics regarding product promotion. Citizen (the Japanese watch company) presented full-spectrum LEDs with a color-rendering index of 96 to 99. Two years ago, I measured their efficiency at 28 to 34 lm/W, and, now, the technician said they improved to roughly 66 lm/W at a 13W total power input for one LED. Simultaneously, without binning (selecting each LED and sorting them according to production color/brightness variations in order to sell them in roughly equal lots), Citizen could reduce the production color variation in two years from 7 McAdam to 3 McAdam (the color difference of 1 McAdam, by definition, is distinguishable to the human eye, in direct comparison).
The same company showed an LED with a reported 116 lm/W that has a lower color-rendering index (approximately 65). What did the datasheet say? Values up to 2,000 hours are measured and guaranteed; further values are honestly marked as estimates. Samples? The company said it will send you one, for free, after the show. Production? Products are available from stock immediately from many, listed distributors.
A few companies displayed organic LEDs (OLEDs). My discussion with Novaled (Dresden, Germany) representatives confirmed my expectations. OLEDs are still in early-stage development; my guess is, they‘re where normal LEDs were 25 years ago, regarding surface brightness, confining environmental operating conditions and flexibility. The development was focused on auto-instrument-panel backlighting, where the claimed life is 5,000 hours. Their main advantage (and possible new applications) is, in the off state, they look like a simple, transparent glass plate.
OLEDs’ only sign-industry application was exit signs.
All OLED booths were quite dark, and rumors were the companies needed other optical attractions (read: young female models) to gather visitors’ attention.
Another important aspect for LEDs in signs is the face material. Thus, I checked what‘s new with Röhm’s acrylics. The “true-LED” series of acrylic face materials, which has been available for a few years, is still state of the art. I’ve been told experiments have shown further improvement in the transmission (which, for white, is approximately 50%, meaning 50% of the generated light is wasted) won’t yield sufficient light scattering and would result in uneven face brightness.
For poster boxes and opaque print frames, an acrylic material with anti-reflective coating will be available soon to prevent reflections from distorting images in bright environments.
Perhaps of interest to the sign business, a seamless T5 fluorescent lamp with double-backed electrodes is available from Osram.
Several companies, such as Hadler (Felsberg, Germany), presented fixtures with built-in power supplies. Because of the electrode position, no dark space appears when multiple lamps are installed in line. The neon company Mutzhas (Essen, Germany) presented this lamp style in custom shapes and colors as a high-output lamp with up to approximately 4,800 lumen per linear meter for daylight, triphosphor white.
Luxim’s (Sunnyvale, CA) FiFi STA lamp series probably will become the long-life, future version of the HID lamp, for use in hard-to-reach billboard places. The RF-powered, electrodeless lamp has a claimed life of 50,000+ hours and overcomes the problems of the famous “fusion lighting” sulphur lamp that was seen approximately 10 years ago: limited RF-generator life, forced cooling and low color rendering.
In summary, never before have I seen so much bad light at a lighting show as this year’s light+building show. The LED hype is at its peak. For me, there‘s no other explanation why proven, more efficient and more suitable lightsources have been expelled, just because they’re not LED. Further, LEDs seem to sell only by the price, especially because the market is flooded with very similar, low-quality products from China.
So, I ask the lighting industry: Are you following the financial-market-hype soap bubble, with the disastrous end that we’re still fighting?
Hopefully not. It’s better to stay with, and improve, known light-source concepts rather than ban them. The next light (not LEDs) + building show in 2012 will tell if we’re back to rational business.