In the LED: Getting the Most Value with Your LED Display

One hundred and twenty five thousand dollars! Wow! Paid hard-earned cash, right out of my pocket, for this baby. But look at this thing …. 300 square feet of full color video display sitting right here in front of my store. Sweet!“ That’s what you were thinking on day one when that big display was hot out of the box and looking mighty fine.

But now it’s a year later, and you’ve been struggling just to keep the display running. You didn’t really notice it at first, but after a while, you became very unhappy with how grainy the images appeared on the screen. You started to notice that some lamps seemed to burn brighter than the others. Some of the green lamps didn’t produce the same deep green hue. You started seeing a patchwork of modules. The whites seem to have gotten pinker.

To make matters worse, the store owner down the street put in a new display shortly after your installation, and it looks much better than yours. The images are crisp, not grainy. The whites look like fresh snow. Out of curiosity, you walk down to his store and ask him what he bought, and he tells you it is a 16mm display. You are shocked because you remember your salesman telling you that you were buying a 15mm display, and he said the lower the number the better the quality. If 15mm should look better than 16mm, why doesn’t yours look better than his?

Feeling frustrated and taken advantage of—and wanting some answers—you contact the salesperson who sold the display down the street.

As it turns out, your good deal wasn’t so good after all. He tells you that your 15mm is really a 22mm; it’s something called a “virtual pitch”. You also have lower quality lamps, and they are degrading very quickly. Worst of all, your display actually has fewer lamps than the display down the street even though you paid about the same price.

This is an LED nightmare that everyone needs to learn to avoid.

So how do you avoid the pitfalls of buying a product that is represented as something better than it really is? What do you need to look for when buying a display?

There are three items to consider before purchasing a new display—total number of pixels, total number of lamps, and brand of lamp.

Always ask for a total pixel count. The total number of pixels is what determines the quality of your image. The more pixels you have, the better the quality of that image. For example, it is hard to create an image of an eye with just three pixels. With a hundred pixels, suddenly that image of an eye goes from just a speck to a true representation of an eye complete with iris, pupil, eyelashes, and eye brow. The number of pixels is a critical metric.

The total number of lamps dictates the price of your display. Most of the cost of any LED display is in the actual number of lamps used. The more lamps you have, the more expensive the display. In the scenario above, you were told you were getting the same pixel density (number of pixels per square inch) as the store down the street; however, there’s a big difference between virtual (ghost) pixels and physical pixels. The only way to make sure you are getting your money’s worth is do an actual count of the lamps you are buying. Misleading you is easy to do if you aren’t familiar with the technology. However, there’s no way to deceive you when you come right out and ask, “How many lamps are in the display that I am buying?”

And finally, the brand of lamp is important. There are recognized quality lamp manufacturers that the industry acknowledges as being “best of breed”. In the past, Nichia and Cree were known as best, but now there are other manufacturers who are competing directly with them. A good quality lamp will prevent that pink snow and individual lamp bright spots. As the display ages, with superior lamps, your image quality will stay fairly uniform even as your display ultimately ages as it approaches 100,000 hours of lifetime.

If you always remember to pay attention to these three rules of thumb, you can buy a display with confidence that it will perform at the highest level of quality for you.

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