Sign & Digital Graphics

The 2015 LED & EMC Report

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L E D & E M C • June 2015 • 19 if you multiplex this pixel, or share the "on time" of a pixel with its neighbors. Multiplexing further reduces the light available for each of the specific pixels. So, once more, to achieve a bright image, you will have to resort to overdriving the LEDs again. So are there any cases in which pixel sharing makes sense? The answer is yes, of course. If your display is running video, you can get a better picture at a lower cost and a lower weight—but the downside is a decrease in the overall life of the product. Perhaps you have a video replay board that is only operating for a few hours on a weekend. Maybe bright- ness isn't an issue for you. You might want a big sign but are concerned about overall weight. Or you have an extremely tight budget, and think you can live with the drawbacks. Any of these situations might make a strong case for pixel shar- ing. It's certainly a decision that seems confusing and contradictory on many levels. However, for the end user who wants to make the most economical choice without sacrificing performance, a true- pitch product is the only answer. If the people viewing the board are more than 200' away, you should consider going to a 20mm. Since they contain fewer LEDs than a true 16mm, these displays are cheaper per square foot, lighter and brighter, and actually yield better static image quality than a 16mm product that uses pixel sharing. Making the Decision Pixel sharing does save on power and weight, but the price you pay is a decrease in content resolution, image crispness and product longevity. The virtual pixel must share LEDs from its neighbors, flashing at a high fre- quency so the eye cannot pick up on it. This works effectively for moving video images, but lends an annoying flicker to static images. So, how can you go about making sure that a product with pixel sharing is the best choice? First, do a test run with your own graphics and images, not the content the manufacturer might provide. Run this test in an environment that your sign will be in once installed (in direct sunlight, South-facing, for example). If the sign looks acceptable under these conditions, then this might be a viable choice for your purposes. Most impor- tantly, however, ask for a warranty that guarantees at least five years of an image quality that has not deteriorated. With advances in LED technology in recent years, such as the incorporation of lighter materials and more efficient electronics, products offering real 16mm and smaller pitches are coming on the market at lower prices than ever before. As end users become more sophisticated as to the ins and outs of the new genera- tion of LED displays, the "virtual pixel" may well be on its way out. In any case, the business owner who intends to invest in an attractive, long- lasting LED display owes himself—and his business—a clear understanding of the many meanings behind the concept of "pitch" in order to get the best from this efficient and productive marketing tool. SDG Pitch is the distance between the clusters of red, green and blue LEDs that make up a single pixel in a sign. Comparing virtual "shared pixel" configuration to true pixel configuration.

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