LEDs Magazine Review - Beriled

LEDSMAGAZINEmainly for the European market. “Through Philips’broad expertisein lighting, its wide capabilities in LEDs and its extensive global reachand resources, we will be able to expand our home-lighting businessfurther,” said Jules Noten, CEO of PLI. “We look forward to becominga global player and industry shaper in the transition towards LEDapplications.”AC LEDSSSC’s Acriche LEDs connectdirectly to the AC mainsAt the electronica trade show,Seoul Semiconductor (SSC)unveiled its Acriche LEDs, aseries of modules designed to rundirectly from an AC powersource. Each LED package contains2two LED chips measuring2150 × 850 μm. There are threedifferent Acriche modules, including a 4 W version with two LEDpackages that produces up to 150 lm, and a four-LED, 8 W versionrated at 300 lm. These have connectors to allow direct attachment toan AC supply. The module boards contain resistors, and SSC says thatthese are used to lower the peak value of the AC power source. “Thisincreases the chip stability, and when the AC electric power source’svoltage fluctuates it can have a buffer effect on the chip structure,”said a company spokesperson.According to the company’s description, Acriche LEDs have“dozens of cells organically connected to each other within a chip”.These cells form two series-connected arrays, corresponding to thetwo directions of the alternating current. Each array is illuminatedalternately for the different directions of current flow. This allowsAcriche LEDs to be directly connected to an AC electric power source.The SSC spokesperson says that, when the light source is considered,the performance of DC LEDs is still a little better than Acrichein terms of lifetime and luminous flux. “However, with respect to AClighting fixures, Acriche performs better because DC LEDs needAC–DC converters, which have a much shorter lifetime and are lessefficient than LEDs.”● More details at www.ledsmagazine.com/articles/news/3/11/14.NEWS & ANALYSISRETAIL LIGHTINGWal–Mart fits refrigerateddisplays GELcore LED lightsWal-Mart is to deploy LED lighting from GELcore in its refrigerateddisplay cases in omore than 500 US stores. The giant retailerexpects that energy cost savings from the retrofit will exceed $2.6 millionannually, compared with incumbent fluorescent technology. Wal-Mart will employ occupancy sensors and LED dimming capabilitiesto reduce the time that the LED refrigerated display cases are at 100%light levels.Wal–Mart reports that subsequent phases of the initiative will beaimed at retrofitting existing refrigerated display cases at many ofits worldwide network of 6689 stores. “We have committed to investup to $500 million annually on energy-efficient technologies,” saidCharles Zimmerman, VP of prototype and new format developmentat Wal-Mart. “It’s our hope that one day all of our reach-in refrigerateddisplay case lighting will use LEDs.”GE says that 8 of the top 10 US grocers/supermarkets are testing orusing the company’s LED refrigerated display lighting. LED lightingoffers a range of benefits. One of these is reduced energy consumptionby lessening the load on the compressor. For every light wattreduced in a frozen-food case, the compressor works less hard, savingabout 0.45 W. On a five-door case, the additional energy savingsfrom a reduced load on the compressor can reach 70 W compared withT8 fluorescent lighting.● More details at www.ledsmagazine.com/articles/news/3/11/16.DISPLAYSBarco supplies LED backdropfor George Michael tourON OUR WEBSITEHigh-power in a 1 mm 2 chip: theorigins of the 350 mA ‘1 W’ LEDFor years, high-power LEDs were defined by two specifications thatseemed to be engraved in stone: that each chip was 1 mm 2 and couldbe driven at 350 mA. This “1 W” LED launched the use of solid-stateillumination in general lighting applications and became the de factostandard in the industry. Ironically, however, these specifications werethe product of serendipitous design decisions rather than deliberateengineering choices that were calculated to generate a specific levelof performance. The design team simply put a stake in the ground andthe rest of the industry followed.● See www.ledsmagazine.com/articles/features/3/11/2.LED display specialist Barco has supplied 3000 of its MiSTRIP LEDmodules to form a highly unusual stage backdrop for George Michael’s25 Live Tour. The modules, playing video and graphics effects, forman unprecedented curved display of LEDs behind and underneath theperformer that can be both stood and danced on.6© Copyright 2006 Cabot Media Ltd. All rights reservedledsmagazine.com December 2006