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Archive for August, 2011

Color LEDs Enable Architectural, Entertainment, And Horticultural Applications

29 Aug

Philips Lumileds adds a deep-red LED to its Luxeon family, while Lebelight Technology claims new brightness record in green LEDs.

While phosphor-converted white LEDs are touted for general-illumination and backlighting applications, colored LEDs can serve in many more applications in architectural, entertainment, horticultural, and other segments. Philips Lumileds has added to its color portfolio with a new deep-red emitter. Lebelight Technology has a green emitter that it says can produce 150 to 160 lm.

Philips has a Luxeon Rebel color portfolio that ranges from royal blue (440-460 nm) to deep red (650-670 nm). The deep-red LED is the recent addition and targets applications such as horticulture and entertainment. Moreover, Philips says that some governments require the deep-red color in railway- and roadway-signaling applications.

Deep-red for safety and horticulture

The deep-red LED differs from the standard-red (620-645 nm) offering. The deep-red color is more visible in safety-centric application and Philips rates it at double the drive current of most of the Luxeon color portfolio. The emitter generates 720 mW of radiometric power or radiant flux at 700 mA.

“For more than a decade, Luxeon LEDs have been the first choice for enlivening city centers and architectural wonders, bringing drama to concerts and performances, and ensuring people can move safely on our public transit systems,” said Steve Barlow, senior vice president of sales and marketing at Philips. “We are committed to the continuous improvement of our color portfolio and have delivered substantial light output increases.”


Luxeon LEDs light Guangzhou TV Tower

Horticulture could prove to be a major consumer of the deep-red LEDs. It turn out that the 660-nm wavelength corresponds to peak chlorophyll absorption in plants as we covered in an article on LED-based horticultural lighting. Plant factories and green houses are moving away from broad-spectrum lights to ones that provide specific wavelengths hoping to induce better plant grow with less energy. Osram has been keen to support such applications introducing deep-red LEDs last year.

The other color in the Luxeon portfolio that has a specialty applicability is the royal-blue LED. It too is characterized at 700 mA delivering 1120 mW, and targets remote-phosphor-based general-lighting applications. Philips introduced the royal-blue LED earlier this year, and we just ran a news story on the remote-phosphor topic with Cree introducing a royal-blue LED.

Brighter green LEDs

Green LEDs, meanwhile have been challenged in terms of lumen output due to a physics phenomenon called the charge separation effect. Research organizations such as Rensselaer Polytechnic Institute (RPI) have been working diligently on brighter green LEDs.

Lebelight Technology of Xiaoyi, China claims to have produced a green LED that delivers 150 to 160 lm at 350 mA of drive current. If the company can cost-effectively produce such a product it could enable advances in general lighting, backlighting, and specialty applications such as horticulture.

Large-screen TV backlights for example can benefit from direct backlighting using clusters of red, green, and blue (RGB) LEDs that improve the color gamut of the picture. But TV makers have gone away from the RGB scheme, in part because they need to combine two green LEDS with each red and blue LED to achieve consistent brightness. Likewise, RGB-based general-lighting fixtures can produce tunable color, but the available green LEDs don’t deliver the needed efficiency.

 
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LEDs May Have Reached “Tipping Point” with Electrical Contractors

23 Aug

A survey of 700 readers of Electrical Contractor magazine showed a majority of contractors believe LEDs are either now ready to replace incandescent and fluorescent lamps or will be ready by the Fall of 2012.

Electrical contractors may be reaching the point where specification and installation of LED lighting, where appropriate, is becoming the rule and not the exception.

Results of a survey of 700 readers of Electrical Contractor magazine indicate a majority of electrical contractors believe LED lamps are now ready or will be ready within a year to replace incandescent and fluorescent lamps.

The publisher of Electrical Contractor, John Maisel, said, “The more we educate [electrical contractors] on the technology and opportunities in the multibillion dollar LED market that’s growing more than 30 percent per year, the greater value they bring to their customers.” Electrical Contractor, which reaches over 85,000 electrical contractors in the US, is published by the National Electrical Contractors Association (NECA) in Bethesda, MD.

Among those readers who responded to the survey, 33 percent of electrical contractors said LEDs are ready to replace incandescent lamps, compared with 23 percent saying LEDs are ready to replace CFLs and 19 percent claiming LEDs are ready to replace fluorescent lamps (see figure).


Market readiness for LED replacement

An additional 33 percent of electrical contractors believe LEDs will be ready to replace these traditional lamp sources within the next two years. The remaining respondents see LEDs becoming more viable later, or they “don’t know” when viability will occur. Of those who said LEDs were not ready or they didn’t know, 19 percent said that high cost was a factor, while 10 percent mentioned needed improvements in performance.

The survey was conducted by the firm Renaissance Research & Consulting (New York, NY) in the Fall of 2010. Participants included contractors working on residential projects, commercial/industrial/institutional (CII) projects and non-building projects (see figure).


Lighting work performed by construction type (Res, CII, NB)

All things to all people?

Lighting is an inherent part of the electrical contractor’s job. As such, it comes as little surprise that 97 percent of respondents indicated they work with indoor or outdoor fixtures (on a combined basis), while 95 percent perform work with lamps, 93 percent with ballasts and 85 percent with controls.

A substantial portion, between 45 and 60 percent of electrical contractors, perform all functions on the job including buying, specifying and installing lighting products. Ninety percent of contractors perform some lamp work, while about 60 percent work on all aspects, meaning they specify and install lamps.

Regarding lamp types, contractors mentioned fluorescent and compact fluorescent lamps the most, while LEDs actually were mentioned the least. However, the report says “ECs are proportionately more involved in LED specification than with other lamp types.”

LEDs on building projects

Beyond this recent survey, Electrical Contractor featured a special supplement entitled The LED Revolution, with its July issue. With articles addressing initial cost and payback, dimming and required drivers, compatibility with controls and LED standards, the issue provides a useful overview to contractors and distributors.

Out of the readership survey came important tips for electrical contractors. For instance, contractors should specify LED luminaires with well-designed optics to ensure the light reaches the intended surfaces. Controls are considered the largest contributor to improved efficiency through sophisticated addressable ballasts along with daylight and motion sensors.

 
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US House Votes Down Incandescent Bulb-ban Bill

10 Aug

The US House of Representatives failed to pass the “Better Use of Light Bulbs Act,” which aimed to repeal the 2007 legislation that will mandate more-efficient replacements for 100W lamps, such as LED-based lamps, beginning next year.

On Tuesday (July 12), the US House of Representatives voted on the H.R. 2417 “Better Use of Light Bulbs Act” that was proffered by the Republican party, members of which believe the government has no place legislating what type of light bulbs citizens buy. The bill failed to achieve the two thirds vote required to repeal the 2007 legislation that mandates more-efficient light bulbs starting next year, and the failure is generally good news for proponents of LED-based solid-state lighting (SSL).

The House voted 233 to 193 in favor of the act. The vote was largely along party lines, although 10 Republicans voted against the legislation while 5 Democrats voted for the repeal.

The new bill ran contrary to the escalating green movement. Lighting is responsible for more than 20% of the energy used in the US. And most see lighting as one of the easiest places to save energy. But the savings come with higher upfront cost of SSL products that must be recovered through savings over long lifetimes.

Republicans created the EISA

Ironically, it was Republican President George W. Bush who signed the Energy Independence and Security Act (EISA) requiring more-efficient light bulbs into law back in 2007. The legislation requires that 100W lamps, or more specifically lamps with a light output of around 1700 lm, operate 30% more efficiently.

In successive years the efficiency requirements will be applied sequentially to 75W, 60W, and 40W lamps. And an even more stringent set of efficiency requirements will kick in later in the decade. The EISA doesn’t ban incandescent lamps but realistically only technologies such as SSL and compact -fluorescent lamps (CFLs) will meet the requirements.

Despite the fact that more-efficient lighting will save significant energy, Republicans, urged on by conservative celebrities including Rush Limbaugh and Glenn Beck, sought to allow citizens to make their own lighting choices. An editorial in the BostonHerald.com joined the protest and called for passage of the new incandescent bulb bill.

In actuality many people who oppose the lighting aspects of the EISA don’t fully understand the details of the legislation. A recent New York Times article described how people are stocking up on incandescent lamps, although in many cases the new bill would not even impact the type of lamps discussed. Indeed the EISA accepts many lamp types including 3-way bulbs, and many decorative-lamp styles.

EISA supporters

The EISA also has strong supporters and there was intense lobbying leading up to Tuesday’s vote that may have been responsible for the defeat. Lighting Science Group CEO Jim Haworth said, “Lighting is the low-hanging fruit in reducing energy consumption: it accounts for 19% of the world’s energy use – and in the United States, 22%; public and commercial buildings represent 60% of the power used for lighting; up to 80% of offices are lit by outdated and inefficient systems; and lighting accounts for 15% of household electricity use. There are 4.4 billion traditional light sockets in the United States alone offering a rapid and practical path for billions of dollars in energy savings through the installation of more efficient lighting.”

Of course many proponents have a vested interest. Lighting Science Group hopes to be a major player the LED-based replacement lamp market. The National Electrical Manufacturers Association, among others, also lobbied to leave the EISA standing.

If you would like more details on the reaction from House members and other interested parties after the vote, the New York Times ran an excellent article with reaction from Texas Republican Joe Barton who proposed the repeal. Many others are quoted in the article.

California and Texas

It’s unclear whether this is the end of the story with the EISA federally, but states within the union are also active in legislation – and headed in vastly different directions. California had passed legislation that accelerated the EISA guidelines starting the transition this year.

Texas, conversely, has acted explicitly to allow manufacture and sale of incandescent lamps in the state going forward. In July, the state passed a measure that essentially makes lamps stamped with “Made in Texas” exempt from the EISA.

 
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Cree Announces Blue LED and Remote-phosphor Licensing Program

10 Aug

Royal Blue XLamp XT-E LED targets remote-phosphor SSL applications, and Cree is offering licenses for its remote phosphor-technology for ready usage by lamp and luminaire vendors.

Cree announced the new XLamp XT-E Royal Blue LED that delivers 525 mW of radiant flux, and targets remote-phosphor solid-state-lighting (SSL) applications. The company will match that LED with a remote-phosphor patent licensing program that will allow lamp and luminaire designers to accelerate the SSL design cycle.

Cree says that the new LED offers “category-leading brightness” along with 2.5-nm bins that it asserts are the industry’s tightest. Mike Watson, Cree senior director of marketing, LED components, said, “The new Cree XLamp XT-E Royal Blue LED outperforms the competition in both elements enabling our customers to design high-performance and low-cost systems.”


Cree royal-blue LED

The LED is based on Cree’s Direct Attach packaging technology that relies on bond pads on the bottom side of the emitter and what the company calls a “eutectic die-attach process” that eliminates bond wires and uses a chemical compound for the bond. That design yields the 525 mW of flux at 350-mA drive current and 85° C operating temperature.

Remote-phosphor technology

Remote-phosphor SSL designs typically utilize a blue emitter — generally considered to be the color that delivers maximum efficacy. The phosphor that generates the white light is coated on a secondary optic or diffuser. Proponents believe such designs deliver better efficacy than do phosphor-converted LEDs. Phosphor-specialist Intematix, for one example, maintains that its remote-phosphor technology can deliver a 30% efficiency advantage.

There are certainly notable examples of remote-phosphor products that achieve superior efficacy. For example, the Philips lamp that was announced as the US Department of Energy (DOE) L Prize winner last week uses a remote phosphor.


Royal Blue XLamp XT-E LED side view

Patent licensing

Cree hopes to help design teams working on remote-phosphor lamps and systems via the patent licensing program. Cree says that a license will allow access to patents that are fundamental to the combination of a blue emitter and a phosphor-coated optical element.

Early this year, Cree announced what is essentially a reference design of a 60W-equivalent LED-based lamp that uses remote-phosphor technology and that according to Cree would meet Energy Star requirements. At the time of that announcement, Cree said that the design relied on patented remote-phosphor technology. It’s not clear if that same technology is included in the new licensing program.


Cree A-lamp reference design

Other royal-blue LEDs

Cree is not the first company to announce a royal-blue LED targeted at remote-phosphor lamps and luminaires. Philips made a similar announcement back in May of a royal-blue LED in the Luxeon ES family of components.

Coincidentally, or not, both the Cree and Philips announcements were lacking a measurement of light output in the more traditional units of lumens (lm). Cree chose to specify its product in the wattage unit that defines the radiometric power or radiant flux of the output.

Originally Philips simply provided a specification of wall plug efficiency for its LED. Subsequently the company has published a data sheet with a rating of 500 mW at 350 mA.

 

Prominence of LED Bulbs

04 Aug

LED bulbs are new style light bulbs which feature energy saving, durable, long lifetime, environment friendly when compared with conventional bulbs. LED bulbs utilizing high efficacy LEDs as light source have much higher luminous flux than conventional bulbs. LED bulbs’ luminous flux can be as 10 times as incandescent bulbs and 2 times as compact fluorescent lamps. LEDs are solid state light source that can last over 50,000 hours, which is as 20 times as incandescent bulbs’ lifetime and 10 times as compact fluorescent lamps’ lifetime. LED bulbs are more durable and shock resistant than conventional bulbs. LED bulbs are more environmental friendly than conventional bulbs thanks to the non-toxic materials they utilize.

LED bulbs are ultra energy efficient due to the high efficacy of LEDs. LEDs for indoor lighting fixtures now have broken the luminous efficacy of 100 lumen per watt. Therefore, LED bulbs can deliver the same light intensity with only 10% power consumption as incandescent bulbs’ and 50% power consumption as compact fluorescent lamps. It means that you can save over 90% energy bills when you switch incandescent bulbs to LED bulbs and also you can save over 50% energy bills if you switch compact fluorescent lamps to LED bulbs. The light that LED bulbs emit is more close to daylight which is more comfortable than the light which conventional bulbs emit.

LED bulbs can last over 50,000 hours, which is much longer than incandescent bulbs’ and compact fluorescent bubs’ lifetime. LED bulbs hardly need maintenance during their lifetime, just install them and leave them alone, you will enjoy the benefits they bring to you. During the lifetime of LED bulbs you will save lots of bulb replacement costs and maintenance costs due to their ultra durability.

All the materials used to manufacture LED bulbs are environmental friendly and non-toxic. Unlike conventional bulbs, LED bulbs are 100% green and do not contain any hazardous materials such as mercury and lead. LED bulbs are recyclable after disposal. In addition, without UV or IR radiation, LED bulbs are harmless to human beings’ eyes. You do not have to worry about healthy issue even if working under them continuously.

 
 
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