For most of the 20th century, neon lighting was the last word in illuminated signage. Consisting primarily of gas-filled glass tubing, these fixtures could be bent into an unlimited number of shapes that radiated multiple warm colors. In the 21st century, it’s looking like LED lights are eclipsing everything else for a number of very good reasons.
Neon light can contain more than neon. Along with neon gas that produces an orange-red hue, hydrogen produces solid red, carbon dioxide produces white, helium creates yellow, and mercury generates a blue light. While neon lights originally had a limited number of colors, it was eventually discovered that the palette could be extended by coating the glass tube with various fluorescent materials. In the hands of skilled artisans, these glass tubes could be sculpted into any configuration. Animation effects could be added by taking advantage of the light’s fast activation time. Another popular method for illuminated signs was placing discrete incandescent bulbs in a matrix and triggering them in sequence to produce simple animations. Mainly because of falling prices, LEDs have overtaken these existing lighting schemes. It’s not the only reason for their success, though.
Cost plays a big part in making LED signs attractive propositions. While they’re initially expensive compared to fluorescent or halogen bulbs, they’re fairly equal to neon because of the added expense of fashioning neon tubes into desired shapes. Signs Manufacturing states, “Afterwards, LEDs pay for themselves by consuming less electricity and especially by needing less maintenance. Using less than half the juice of a fluorescent light or one-fifth that of a neon light is nice, but also consider that LEDs will last roughly 50,000 hours at full power.” After that, they gradually fade in brightness, so they’re still viable in a display sign for some time. They’re also made of solid material, so they won’t break easily from any rough treatment.
The ultimate advantage of LEDs is that they can be placed in an array and operate like a TV screen. LED bulbs can be smaller than 2 millimeters. This results in lightweight signs often only an inch in thickness. An LED bulb can be switched on and off in about one-millionth of a second. To create fluid animation, a screen must be renewed at least 25 times per second. Neon, fluorescent, halogen, and other lights just can’t keep up. On top of this, flashing these other bulbs cuts into their lifespans. This is not a problem for LED lights. Unlike some of the others, LEDs can also fluctuate in their output. The big payoff, though, is that since the sign is animated, it can be updated as desired without being replaced.
https://en.wikipedia.org/wiki/Neon_lighting
https://en.wikipedia.org/wiki/Light-emitting_diode
www.lrc.rpi.edu/resources/newsroom/pdf/2003/LEDSignage.pdf
