Fascinating New Generation OLEDs

With their minuscule energy consumption and 20-year life expectancy, LED light bulbs have grabbed the consumer’s imagination.

But an even newer technology is intriguing the world’s lighting designers: OLEDs, or organic light-emitting diodes, create long-lasting, highly efficient illumination in a wide range of colors, just like their inorganic LED cousins. But unlike LEDs, which provide points of light like standard incandescent bulbs, OLEDs create uniform, diffuse light across ultrathin sheets of material that eventually can even be made to be flexible.

Ingo Maurer, who has designed chandeliers of shattered plates and light bulbs with bird wings, is using 10 OLED panels in a table lamp in the shape of a tree. The first of its kind, it sells for about $10,000.

He is thinking of other uses. “If you make a wall divider with OLED panels, it can be extremely decorative. I would combine it with point light sources,” he said.

Other designers have thought about putting them in ceiling tiles or in Venetian blinds, so that after dusk a room looks as if sunshine is still streaming in.

Today, OLEDs are used in a few cellphones, like the Impression from Samsung, and for small, expensive, ultrathin TVs from Sony and soon from LG. (Sony’s only OLED television, with an 11-inch screen, costs $2,500.) OLED displays produce a high-resolution picture with wider viewing angles than LCD screens.

In 2008, seven million of the one billion cellphones sold worldwide used OLED screens, according to Jennifer Colegrove, a DisplaySearch analyst. She predicts that next year, that number will jump more than sevenfold, to 50 million phones.

But OLED lighting may be the most promising market. Within a year, manufacturers expect to sell the first OLED sheets that one day will illuminate large residential and commercial spaces. Eventually they will be as energy efficient and long-lasting as LED bulbs, they say.

Because of the diffuse, even light that OLEDs emit, they will supplement, rather than replace, other energy-efficient technologies, like LED, compact fluorescent and advanced incandescent bulbs that create light from a single small point.

Its use may be limited at first, designers say, and not just because of its high price. “OLED lighting is even and monotonous,” said Mr. Maurer, a lighting designer with studios in Munich and New York. “It has no drama; it misses the spiritual side.”

“OLED lighting is almost unreal,” said Hannes Koch, a founder of rAndom International in London, a product design firm. “It will change the quality of light in public and private spaces.”

Mr. Koch’s firm was recently commissioned by Philips to create a prototype wall of OLED light, whose sections light up in response to movement.

Because OLED panels could be flexible, lighting companies are imagining sheets of lighting material wrapped around columns. (General Electric created an OLED-wrapped Christmas tree as an experiment.) OLED can also be incorporated into glass windows; nearly transparent when the light is off, the glass would become opaque when illuminated.

Because OLED panels are just 0.07 of an inch thick and give off virtually no heat when lighted, one day architects will no longer need to leave space in ceilings for deep lighting fixtures, just as homeowners do not need a deep armoire for their television now that flat-panel TVs are common.

The new technology is being developed by major lighting companies like G.E., Konica Minolta, Osram Sylvania, Philips and Universal Display.

“We’re putting significant financial resources into OLED development,” said Dieter Bertram, general manager for Philips’s OLED lighting group. Philips recently stepped up its investment in this area with the world’s first production line for OLED lighting, in Aachen, Germany.

Universal Display, a company started 15 years ago that develops and licenses OLED technologies, has received about $10 million in government grants over the last five years for OLED development, said Joel Chaddock, a technical project manager for solid state lighting in the Energy Department.

Armstrong World Industries and the Energy Department collaborated with Universal Display to develop thin ceiling tiles that are cool to the touch while producing pleasing white light that can be dimmed like standard incandescent bulbs. With a recently awarded $1.65 million government contract, Universal is now creating sheetlike undercabinet lights.

“The government’s role is to keep the focus on energy efficiency,” Mr. Chaddock said. “Without government input, people would settle for the neater aspects of the technology.”

G.E. is developing a roll-to-roll manufacturing process, similar to the way photo film and food packaging are created; it expects to offer OLED lighting sheets as early as the end of next year.

“We think that a flexible product is the way to go,” said Anil Duggal, head of G.E.’s 30-person OLED development team. OLED is one of G.E.’s top research priorities; the company is spending more than half its research and development budget for lighting on OLED.

Exploiting the flexible nature of OLED technology, Universal Display has developed prototype displays for the United States military, including a pen with a built-in screen that can roll in and out of the barrel.

The company has also supplied the Air Force with a flexible, wearable tablet that includes GPS technology and video conferencing capabilities.

As production increases and the price inevitably drops, OLED will eventually find wider use, its proponents believe, in cars, homes and businesses.

“I want to get the price down to $6 for an OLED device that gives off the same amount of light as a standard 60-watt bulb,” said Mr. Duggal of G.E. “Then, we’ll be competitive.”

LED Lights Show Great Promise

As we all know that LED technology shows great promise in lighting the way for Tech to a more economic and environmentally-friendly direction.

Facilities faculty has completed several lighting renovations already on campus, including converting all the lighting in the Tennenbaum Auditorium to LED lamps. This project alone reduced electricity consumption by 39.2%, and light per square foot more than doubled. They also installed LED can lights on the second floor of the Price Gilbert Library.

“We are currently working on several projects in the IBB building to convert high ceiling fixtures to LED and will eventually expand this to other buildings. The architecture building is next on the list,” said Sanford Fong, Facilities department Electrical Engineer I.

Heat, output and energy usage are the greatest factors in LEDs’ benefits. Since the lights do not rely on a filament, they don’t burn out as quickly and less of the energy emitted is heat (very beneficial for stage work, which is often under extremely hot rows of lights). Since less energy is emitted as heat, it does not require as much energy to produce the light, saving money.

Thanks to a recent cost drop in semiconductor material, they are now a viable option for widespread use. This has opened a window for mass-emplacement of LEDs, like in department stores.

Walmart is pursuing improvements to energy and cost savings by installing LED lighting in their refrigerated cases. The new fixtures and dimming capabilities could net 66% in energy savings. If 500 Wal-mart stores were to use these, it would reduce carbon dioxide emissions by 35 million pounds and save the company $2.6 million per year. The lights could add over three years to the refrigerated cases’ lighting lifetime.

LED lighting can also be applied to large parking lot lights, medium hallway and stairwell lights and small classroom lights. They can last over 50,000 hours (over five years) and the lower power consumption with equal or greater luminosity than conventional lighting could save big money for Tech.

“LEDs save a great deal over incandescent lamps. For example, the can light we are installing in the Petit building is a 12-Watt fixture comparable to an 80-Watt incandescent in lighting output,” Fong said. Such a fixture could save 85% in energy.

Facilities will soon procure a street light test unit to evaluate more demanding applications on campus like streetlights, emergency lights and shop lights. Thanks to the higher power output and longevity, any light fixture that is on a great deal of time or is too hard to reach is a good candidate for an LED application.

Indoor lighting sees a change for the better as well. The pervasive use of fluorescent lighting in classrooms has garnered criticism for eye strain and headaches from the (though too fast to notice) lights’ high-frequency flickering; however, LED lighting is flicker-free. Fluorescent lamps are also less efficient, less longevous, and less environmentally friendly (they contain mercury). In this sense, changing the lights may actually directly improve student and faculty health and performance.

Tech has been a leading institution in LED technology. In 2002, ECE professor Russell Dupuis earned the highest national honor in science, the National Medal of Technology, for his work in developing and commercializing LEDs in applications like traffic lights and automotive lighting.

Ultrathin Inorganic LEDs

There is now a new process under development to create ultrathin, ultrasmall inorganic light-emitting diodes (LEDs) and assembling them into large arrays, which offers new classes of lighting and display systems with interesting properties.

Applications for the arrays, which you can print onto flat or flexible substrates ranging from glass to plastic and rubber, include general illumination, high-resolution home theater displays, wearable health monitors, and biomedical imaging devices.

“Our goal is to marry some of the advantages of inorganic LED technology with the scalability, ease of processing, and resolution of organic LEDs,” said John Rogers, the Flory-Founder chair professor of Materials Science and Engineering at the University of Illinois.

Compared to organic LEDs, inorganic LEDs are brighter, more robust, and longer-lived. Organic LEDs, however, are attractive because you can form them on flexible substrates, in dense, interconnected arrays. The researchers’ new technology combines features of both.

“By printing large arrays of ultrathin, ultrasmall inorganic LEDs and interconnecting them using thin-film processing, we can create general lighting and high-resolution display systems that otherwise could not be built with the conventional ways that inorganic LEDs are made, manipulated, and assembled,” Rogers said.

To overcome requirements on device size and thickness associated with conventional wafer dicing, packaging, and wire bonding methods, researchers developed epitaxial growth techniques for creating LEDs with sizes up to 100 times smaller than usual. They also developed printing processes for assembling these devices into arrays on stiff, flexible, and stretchable substrates.

As part of the growth process, a sacrificial layer of material embeds beneath the LEDs. When fabrication is complete, a wet chemical etchent removes this layer, leaving the LEDs undercut from the wafer but still tethered at anchor points.

To create an array, a rubber stamp contacts the wafer surface at selected points, lifts off the LEDs at those points, and transfers them to the desired substrate.

“The stamping process provides a much faster alternative to the standard robotic ‘pick and place’ process that manipulates inorganic LEDs one at a time,” Rogers said. “The new approach can lift large numbers of small, thin LEDs from the wafer in one step, and then print them onto a substrate in another step.”

By shifting position and repeating the stamping process, LEDs can transfer to other locations on the same substrate. In this fashion, you can create large light panels and displays from small LEDs made in dense arrays on a single, comparatively small wafer. And, because the LEDs can be placed far apart and still provide sufficient light output, the panels and displays can be nearly transparent. The thin device geometries allow the use of thin-film processing methods, rather than wire bonding, for interconnects.

In addition to solid-state lighting, instrument panels, and display systems, the new method also allows for flexible and even stretchable sheets of printed LEDs, with potential use in the health-care industry.

“Wrapping a stretchable sheet of tiny LEDs around the human body offers interesting opportunities in biomedicine and biotechnology,” Rogers said, “including applications in health monitoring, diagnostics, and imaging.”

New High Performance LED Lighting Systems

It is reported that AeroLED sponsored a media lunch today at AirVenture 2009 to introduce their new line of high performance LED lighting solutions. Based on super-bright LED technology, which is fully replaceable with original lighting systems, pronounced “aerolead” the company produces retrofit and OEM lighting options.

Nate Calvin of AeroLED reported the company’s product is a direct replacement for existing incandescent, or “legacy systems” products now in the field, including a replacement for the GE 4509 landing light bulb. Components include options for replacement of navigation and strobe units as well.

Calvin said all components exceed FAR requirements for lumen output. Stating that incandescent systems operate in the 2500 Kelvin range whereas the AeroLED product operates in the 6500 Kelvin range, providing a more white colored and intense light output. The lighting is directional for the strobe application, more closely matching the diminishing requirements from horizontal to vertical plane of the FAR’s. The units are also on the order of 4 times lighter than traditional systems with significantly lower amperage draw.

Initial products were offered to the experimental and homebuilt markets to facilitate a positive cash flow and to support FAR 23 and TSO testing requirements for certified systems. An added benefit to this business approach was the opportunity to receive feedback from the initial customer base. AeroLED also allowed OEM customers to provide opinions for improvements. Calvin stated that all the feedback was considered key to current product line development, resulting in a superior product.

The Pulsar series is the first all LED nav and strobe light combination according to Calvin. The units are ruggedly constructed having gone through complete and thorough vibration and abuse testing, including installation on aircraft equipped with diesel engines that destroyed incandescent bulbs in as little as 10 hours. The units are hermetically sealed and are displayed under water to demonstrate their durability for all weather operation. Calvin quipped that the underwater display was a bit “cheesy” but proved to be an eye catcher and brought people over to investigate. Testing on the units has indicated a life expectancy of around 60,000 hours, well beyond most airframe lifetimes. While not specifically stating a price for the components, Calvin said they were comparable to costs of traditional lighting systems when replacement bulbs and power supplies over the life of the aircraft were factored in.

All AeroLED units have built in overtemp protection and offer very low RF emmisions and will not interfere with radio operations. Operating on 9-36 volts the systems do not dim, as incandescent lights do, at lower voltage levels and deliver the same lumen output regardless of input voltage.

AeroLED is committed to providing a see and avoid product. The company believes, and is receiving encouraging reports, that their system allows much greater visibility at a longer range than any other system currently available. All systems have wigwag capability allowing spotting far in advance of typical legacy systems and AeroLED systems are more visible in daytime than other systems. PMA certification is expected by year end.

How to Make an Old House into a Modern

This artical shows you how to push a 1920s house into a modern, low-carbon age. The last few touches – appliances and rare light bulbs.

After spending the past year reducing the home’s heating bills by adding stacks of insulation, the owner has now turned her attention to slashing her electricity needs. She buy electricity from Good Energy which is a 100% renewable electricity supplier, but she would like to reduce our dependence on it, as all electricity is expensive – green or not. She monitor her energy usage with weekly measurements taken directly from both the gas and electricity utility and currently the house consumes 8kWh of electricity every day.

As part of her drive to save eneergy, She has reviewed the efficiency of all of her electrical appliances. Fridge freezers are significant consumers of electricity in the average house because they are switched on 365 days a year. As she was old, she recently replaced it with an A-rated one to minimise energy usage. Their television is an old-fashioned boxy cathrode ray tube, which is quite energy-hungry, consuming 300 watts per hour when on. The plan – when she has the money – is to change it over to a LCD type. They’ll plan their purchase with a great site called Sust-It which you can use to determine the energy cost per year of new tellies and other products.

What else? Well, she changed most of our conventional light bulbs to energy-savers several years ago. That was easy with standard bulbs, so now she is replacing the more obscure ones.

The garage security floodlight was rated at an energy-guzzling 500 watts – the equivalent of around 50 standard energy-saving bulbs. Although it produced an instant bright light , it was repeatedly set off by animals wandering into the garden at night. So she found a low-energy bulb from B&Q which, although less than half as bright, consumes just 18 watts and reaches full brightness within a few seconds. B&Q now sells a better version using an incandescent bulb for instant bright white light, but after a few seconds the more efficient but slower compact fluorescent bulb takes over.

Continuing outside, our garden lights used to consume only 6 watts each, but having eight of them she was determined to replace them with a more efficient option. Compact fluorescent bulbs don’t exist for such a small wattage so an LED light was the obvious choice. She has now replaced each of them with a very bright 1 watt LED version which nicely lights up the path to the house. A timer ensures the overall energy consumption is minimised.

She has used LED technology inside too. Earlier in the year she bought several Deltech LED bulbs from ebulbshop.com and was very impressed with its brightness and warm-white colour. It matches the incandescent GU10 bulbs (one of the most common spotlight-style fittings) very well and most importantly it has the same physical size, so it fits in her bathroom ceiling’s recessed bulb-holders. These GU10 LED bulbs consume just 5 watts each but come close to the light output from their 50 watt incandescent equivalents. They won’t pay for themselves for more than 10 years because they’re so expensive up-front, so I justify the LEDs on the grounds that their carbon payback is immediate.