Sign & Digital Graphics

December '14

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26 • December 2014 • S I G N & D I G I T A L G R A P H I C S ELECTRIC SIGNAGE W hat is a white LED, really, but the sum of its parts? There are cur- rently two ways to make a white LED: by adding a phosphor over a blue LED or by combining red, green and blue (RGB) LEDs packed tightly together and controlled in such a way as to blend into white light. LEDs made using the RGB method are mainly used for electronic message White LEDs provide even more lighting capacity for today's sign applications B y R e G A N D I C k I N S o N Regan Dickinson is the former executive editor for Sign Business and Digital Graphics magazine. He currently resides in Denver, where he contin- ues to follow the signage industry. centers, electronic billboards, jumbo- trons and the like in order to create video pixels, not just in white, but in millions of colors. For channel letter, cabinet lighting and also backlit displays, LEDs made using the phosphor method are used exclusively. "The blue light from the blue dye excites the phosphor and emits white light. If you go the RGB route, you need a controller, so every manufacturer and LED integrator uses phosphor con- version to create a white LED for sign lighting, and that's where a lot of the improvements have been made," says Bruce Quaal, director of engineering for Sloan LED. That's why white LEDs lagged behind red LEDs as far as output, efficiency Lighting the Way with White LEDs W H I T e L e D T e C H N o L o G y White LEDs have continued to evolve and improve, becoming better and more efficient over time. (Image courtesy of CAO Lighting)

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