The Advantages of LED Lights

As we all know that the future of energy efficient lighting is LED. Not only are LED’s environmentally friendly, the light represents a true white light. A recent press release printed in the Village News on ways to cut energy expenditures missed the mark completely.

Although it is true that CFL bulbs do save energy, they also contain mercury, which is a hazardous material, and these bulbs cannot be disposed of easily. If the bulb is broken, there is a huge problem because the mercury is disbursed throughout the area.

The future in lighting is the use of LED (light emitting diodes) lamps.

First, the operational life of current white LED lamps approaches 100,000 hours. The key strength of LED lighting is reduced power consumption approaching 80 percent efficiency, compared to an incandescent lamp, which operates at about 20 percent efficiency. LED lamps are now available on the Internet and at Wal-Mart.

If, in fact, a bulb burns out in your lifetime, it can be disposed of easily and if broken there is no contamination.

I would urge all Village News readers to learn about LEDs and stop purchasing the dangerous CFL mercury contained lamps.

The folks responsible for traffic lights have started replacing the red, yellow and green lamps with LEDs; you can distinguish the LED lamp because the light is made up of clusters of round LEDs which make up the light.

I recently purchased a GE PAR 30 long neck LED lamp at Wal-Mart to try in my kitchen ceiling. I am very pleased and it only draws 10 watts of power, compared to the 65 watt incandescent bulb that the LED replaced.

Comparing Xenon Lights and LED Light

An updated study has been published by Limited, developer of thin-form supercapacitors that compare flash solutions for camera phones — xenon, standard LEDs powered by a battery, and high-current LEDs powered by a supercapacitor using the company’s BriteFlash(TM) power architecture. The study tested each solution’s ability to deliver the light energy needed to take digital-still-camera-quality pictures in low-light conditions, and also compared shutter requirements, ease of design-in, safety and size.

The original report from October 2006 compared light power and energy using 1.3 to 3.2-megapixel camera phones. The new report includes data from 5-megapixel camera phones released in the last year, and also considers advancements in camera sensors, xenon flash units, high-power white LEDs (WLEDS) and LED flash drivers.

Tests again showed that the LED BriteFlash approach delivers more light energy than most xenon flashes in a thin form factor suitable for slim camera phones and digital cameras.

Clear pictures in dim environments require sufficient light energy — the total amount of light received by each pixel in the camera sensor — during image-capture time. “People often wrongly assume that light power, which is the brightness or intensity of the flash, is the key because it’s what draws our attention, but it’s really the light energy that counts,” said Pierre Mars, CAP-XX vice president of applications engineering.

To calculate light energy, one would multiply light power (in lux) by the duration of the flash exposure (in seconds): Light power (lux) x flash exposure time (sec) = light energy (lux.sec). Ten to fifteen lux.sec of light energy is ideal for high-resolution pictures:

–  Xenon flash tubes driven by electrolytic storage capacitors deliver
higher light power, but over a very short flash exposure.
–  High-current LEDs driven by a supercapacitor deliver lower light
power, but over a longer flash exposure to generate more light energy.

Flash solutions tested:

–  Xenon: SonyEricsson K800, LG KU990, Nokia N82 and Samsung G800, all
with 5-megapixel cameras but with varying size electrolytic storage
capacitors.
–  Standard battery-powered LEDs: Nokia N73 (3.2-megapixel) and N96 (5-
megapixel)
–  Supercapacitor-powered LEDs: To demonstrate the BriteFlash approach,
CAP-XX used a small, thin (20mm x 18mm x 3.8mm thick), dual-cell
supercapacitor to drive a two-LED array of Philips LUXEON® PWM4s at 2A
each or 4A total during the flash pulse.

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.

Novel LED Key Light

Do you have the trouble that always finding keys at home? The LED Key Light from Lexon stands out among a host of other keychain LED lights that resemble pigs, chickens, laser pointers and whatnot by looking like… a key.

Available in green, red or purple, the LED light is powered by a pair of CR1220 button batteries and the case can be easily opened without using tools for quick battery changes on the go.

The outer case is made from soft rubber – just squeeze once and the mini LED in the key’s nose end comes on; squeeze again and it turns off. The key light comes with a ring-type clip which allows for the addition of actual keys, or facilitates attachment to purses, rucksacks, belt loops and so on.

Using the LED Key Light, you will never find your keys everywhere.

Long-life Panasonic’s LED Lightbulb

How often do you change lightbulbs? Every few months, maybe? It is found that the early generation led light bulbs are pretty weak. Well, when Panasonic’s new LED bulbs hit shelves, change that time frame from months to decades.

Yes, these insanely efficient bulbs keep shining and shining, providing the brightness of a traditional 60-watt bulb. Of course, they won’t be cheap, with pricing set at about $40 a bulb in Japan when they hit stores in October. But seeing as they cost a mere $2 to run per year in energy costs and last 19 years, that seems like a good deal in the long run.

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.”

LED Backlighting

It is said that energy-saving flat-panel television sets are about to become common in shops, spawning a whole new range of technical words to understand in Berlin.

Most manufacturers believe the best way to reduce TV power consumption is to change the type of lamp at the back of the flat panel, as well as to devise clever ways to reduce wasted light output.

The newest liquid-crystal-display (LCD) television sets are to feature LED backlights instead of the cold cathode fluorescent lamps (CCFL) which have done the job in the past. LED stands for light- emitting diode.

That is where the confusion starts, because at the same time, the electronics industry has been trying, without much success, to develop TV-sized displays where the image itself is formed by a matrix of LEDs.

LED backlighting has got nothing to do with that technology: all it changes is the light source that shines through the LCD screen.

Word has been spreading for a decade that LED light bulbs are more efficient than fluorescent lamps, so it is no surprise that TV manufacturers are also turning to this new light source.

Philips, for example, claims an energy saving of 40 per cent on its televisions.

The different ways of configuring this new type of backlight are sure to set off more confusion.

The simplest way to deploy the LEDs is around the four edges of the screen and let the light diffuse across the back of the screen. This is cheaper, and salespeople will make a point of explaining that these ‘edge-lit’ displays are even thinner than their predecessors.

‘For the bigger screens, this requires about 500 LEDs,’ explains Peter Koch of LG Germany.

More expensive are the so-called direct LED backlights. Instead of being placed around the edges, these LED lamps are arrayed right across the back of the screen. Direct-LED backlighting is a smart idea because the intensity of the light can be dimmed behind dark parts of the image. This ‘local dimming’ creates deeper, more natural blacks.

‘If the image is of people under a night sky,’ all the LEDs behind the sky will be turned off so that it really seems dark,’ explains Sascha Lange of Toshiba Germany.

This matters, because LCD televisions are often thought to be a degree inferior when compared to plasma flat-panel televisions. The black on existing LCD screens is generally a dark grey, and colours generally seem washed out when viewed off-centre.

Over time, local dimming also helps to save electricity and keep the TV set cooler.

The new backlights generally use LEDs that give off white light, but there is a third variant, the so-called RGB backlight system, which uses a mixture of red green and blue LEDs.

This will only be offered in the most expensive sets, aimed at buyers who want the very best. In fact, television broadcasts do not demand such a subtle graduation of colours, but the difference will be visible while watching the highest-quality high-definition films from Blu-ray discs.

Energy Saving Star – LED Lighting

In your home, lighting may be 10 percent of your bill. But in an office building it’s probably 40 percent, and so if you reduce your lighting energy consumption by a large fraction, the savings will be huge,” said James Brodrick, who leads the DOE’s solid-state lighting program.

A fact sheet from Brodrick’s office says this about LEDs: “In the coming decade, they will become a key to affordable net-zero energy buildings, buildings that produce at least as much energy annually as they use from the grid.”

The technology is advancing quickly, and costs will continue to drop, Brodrick said. The DOE tests LEDs and sets performance and efficiency guidelines under its Energy Star program.

LEDs are directional lights, used in recessed lighting and under-counter lights, for example. They’re not yet available as bulbs that cast light all around and fit in ordinary sockets.

“There’s an enormous and exciting potential, but we have a long way to go before we see anything besides directional lighting,” said Jeffrey P. Harris, the vice president for programs at the Alliance to Save Energy, a nonprofit group that promotes energy efficiency.

Even so, LEDs already are used to light offices, hotels, restaurants and other businesses.

The DOE predicts that LEDs will have better performance capability than fluorescent lighting in the next few years, and that they’ll continue to improve after that. They’re now comparable with fluorescent fixtures in efficiency, and the DOE says its Energy Star LEDs last two to five times longer.

Cost is the biggest reason that LEDs aren’t used more widely, Brodrick said.

LEDs have other advantages: They can be dimmed, don’t emit heat, don’t contain mercury – unlike compact fluorescents – and can produce warm-toned light.

Home Depot, the world’s biggest retailer of light bulbs, is starting to stock LED bulbs this summer and plans to have 10 kinds by September, said Jorge Fernandez, who’s in charge of light bulb purchases for the company.

Philips is working on many kinds of LEDs, including one to replace a 40-watt incandescent bulb that’s scheduled to be available next year, she said.

Derrick Hall of RE/Construct Inc. in Asheville, N.C., said that residential customers weren’t asking for LEDs because of the high upfront cost. Still, he’s hearing of some nonresidential customers who are looking into LEDs for the energy savings.

LEDs are much better than other lighting options, Hall said. The quality of the light is “far superior,” they offer big energy savings and there’s no cost to society for dealing with mercury, he said. Mercury, a neurotoxin, is found in small amounts in compact fluorescent bulbs.

How to Choose the Right Light Bulb

Until recently, most of us have used the incandescent lighting, which renders the color of objects more closely to that of natural light, in our homes. Fluorescent light was harsh and cold and typically used in offices.

Light is categorized by its color rendering index, or CRI for short, and its color temperature.  CRI is how a light source, a bulb, causes the color of an object to appear to our eye and how well variations in color and shade are duplicated in comparison to natural light.

The CRI number is a rating from 0 to 100, the higher the CRI number the better the color. An incandescent bulb has a CRI of 100. Fluorescent lights can have CRIs of anywhere from 50% to 99%.

Color temperature is expressed on the Kelvin scale (K) is the color appearance of the bulb and the light it produces.

The color temperature of lamps makes them visually “warm,” “neutral” or “cool” light sources. The lower the temperature (2700-3000K) , the warmer the source, yellow-red colors. The higher the temperature(5000K) the cooler the source, green-blue color range.

How this all applies to us when we go to buy light bulbs at Home Depot is that  we generally want light that will  give us the best color rendering, a high CRI number, usually with a neutral or warm color temperature, a lower Kelvin number.

Originally these parameters’ were only met by incandescent lighting, but that is not the case anymore. The compact fluorescent bulbs available today have CRI numbers and light quality that closely matches that of incandescent bulbs. Although compact fluorescent light (CFL) bulbs tend to be more expensive they convert electricity into light much more efficiently than incandescent. The lower energy cost of the CFL can offset the higher cost of the bulb. Compared to incandescent bulbs,  fluorescent bulbs use less power for the same amount of light and usually last longer

An article in Wikipedia states that  ” In the United States, a compact fluorescent light  can save over $30 dollars in electricity costs over the bulb’s life time compared to an incandescent bulb and save 2,000 times its own weight in green house gasses. ”

Many compact fluorescents are designed to replace incandescent bulbs and can fit into most existing fixtures.

A problem with compact fluorescents bulbs is that they are made with a small amount of mercury. This mercury  requires that they be disposed through a hazardous waste disposal program, they cannot be put in the regular trash.

Another type of light is the LED. The LED appears to be the bulb of the future. Although expensive LED bulbs can produce light that is comparable to incandescent.

LED (Light Emitting Diode) last longer that compact fluorescents, they use less energy than traditional bulbs and potentially, compact fluorescents. LED lights are made in all sizes and shapes. LEDs do not contain mercury so their disposal is not a problem.

An article in the New York Times quotes Charles F. Jerabek, the president and chief executive of Osram Sylvania, a unit of Siemans as stating “In the US 78 percent of the public is completely unaware that traditional light bulbs will be phased out in 2012.”

As we all konw that light bulbs should be more energy efficient, and incandescent bulbs will be a thing of the past.