Outdoor LED: Historic Review and Trends for Modern Day Use

by Wayne Rasor

Outdoor LED boards have been growing in popularity as the world moves from static signage to digital sign options. Back in the 1990’s, these board’s ancestors existed as primarily time and temperature units illuminated by incandescent light bulbs—definitely not the most power efficient solution. While the invention of LEDs, also known as “light-emitting diode,” as an illumination source was discovered back in the 1960’s, the cost was not ready for the commercial market just yet. It wasn’t until the 1990-2000’s that the cost of LED’s started to lower and get closer to the cost of existing incandescent light sources. It began with warm colors, such as red and yellow. Cool colors, like blue and especially white, were still expensive when compared to traditional light sources. During this time, the advent of monochrome LED boards in red and amber colors hit the market as a comparable alternative to existing incandescent message boards. They were close in cost with a huge savings in power consumption.

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As LED technology progressed and cool color LED’s started to become more affordable, the advent of full color LED message boards appeared. Now that a single LED pixel could house a red/green/blue (RGB) LED cluster, most colors could be reproduced by simply varying the intensity of each LED in the cluster. At first the boards were capable of creating up to 256 different colors, then 260,000+ colors and finally to the true color spectrum of 16.7 million + colors.

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Today, LED message boards are seeing consistent enhancements including creating pixels with different combinations of red, green and blue LED’s that create more vivid and accurate color output. The real race is decreasing the pixel pitch, or the distance between each pixel. Years ago, the average was between 24mm and 20mm, then 16mm and just recently down to 10mm. The closer the pixels are the together, the closer the viewer can stand in front of the board and be presented with a solid full-color canvas, without seeing individual pixels. Indoor LED boards have reduced their pixel pitch down to 2-3mm, giving an almost full HD resolution at a close viewing distance. It won’t be long until outdoor boards are in that range for a much higher resolution.

As digital sign solutions become integrated into our everyday surroundings, from gas stations and restaurants to airports and building directories, it is amazing to see how fast the LED field has advanced. LED technology will continue to progress at an increasing rate for better color and display quality. At the same time, board technology will move to a modular design to allow for more flexibility and unique installations.