LED technology turns 50


It may be hard to believe, but light-emitting diode (LED) technology is older than we are (but still younger than most of our parents). We often see advertisements for LED TVs and monitors, which are eventually going to replace liquid crystal display (LCD) TVs and monitors in the market. Who invented LED technology? One Nick Holonyak, who presented his idea to General Electric (GE) in 1962. Although now we have multiple colors of LED light, the original color was red—not because red was Holonyak’s favorite color or as a result of some accident (although plenty of inventions and scientific advances have been the result of accidents), but for scientific reasons.

LEDs are made by building layers of semiconductor crystals on a wafer. As the layers are added, dopants are added to determine the color of the LED. The tiny wafer is placed into molten liquid and metal contacts and leads are then added. The mixture used in the first LEDs—gallium arsenide phosphide—produces a natural red color. So, for much of its early history, LEDs were red. They also became synonymous with warning lights or indicated that a device had low battery, something that is still done to this day.

By 1971, the price of LEDs went down far enough so that consumers could afford them, and the Busicom LE-120A “HANDY-LE” was the first calculator to use the relatively new segment LEDs in a display, with seven different LEDs in one display for about $400. The following year, the LED made its appearance in watches manufactured by Pulsar, and although these watches were $2,100, they were a major breakthrough for LED technology. However, it drained batteries rather quickly, and you had to press a button if you wanted to see what time it was constantly. Pulsar combined the LED calculator into a watch by 1975.

Eventually, LEDs stopped being red, and now new colors and possibilities opened up. In 1993, Japanese scientist Shuji Nakamura discovered a breakthrough in doping (the name for the process by which manufacturers introduce impurities into an LED to change its color properties) that led to bright blue LEDs. Blue LEDs with yellow phosphor coatings gave us the white LED and a whole host of new applications. This was the first indication that LEDs would eventually become the standard rather than just something niche, even though 1993 was a time when the bulky CRT monitors, and, to a lesser extent, LCD monitors were dominating the market.

Kids of the 90s should remember those shoes that lit up every time you applied pressure to the shoe. This was also a demonstration of LED technology. They were pretty much in at the time, so much that even though these shoes were marketed towards kids, adults started wearing them, and it became a mainstay in 90s culture. But that was only the beginning, because at the turn of the century, the LED light found its way into the optical mouse.

The optical mouse has been around since the 1980s, but in 1999, Microsoft invented the IntelliMouse Optical. Remember that rolling ball in your mouse that moved your mouse around and attracted so much dirt you constantly had to clean the inside of your mouse? LEDs made that obsolete. Indirectly, the mouse pad also became obsolete, because that was the only thing that kept the rolling ball relatively cleaner than its surroundings, although the mouse pad was just as dirty as the insides of a rolling ball mouse.

In the new century, LED technology began to be used in TVs, monitors, and more recently, smartphones and tablets. Sony was the first to put an LED TV on the market in 2004, the 46″ Sony Qualiia 005, and it cost $10,000 (Php 425,000). Nowadays, with advances in technology, a 60″ LED TV would probably cost you around $1,500 to $2,000 (Php 63,750 to Php 85,000), depending on features and manufacturer. Organic light-emitting diodes (OLEDs), the next step in LED technology, are even more beneficial to the environment: they don’t suck up as much energy as their predecessors and just need an electrical current and no backlighting is necessary. This also reduces the thickness of the devices they are used in. At CES 2012, a 55″, 4 mm-thick LG OLED TV was introduced, and it weighs a mere 16 pounds.

LED technology has come a long way in the past 50 years—from just becoming a red light synonymous with warning or danger to being used in large screen TVs and monitors, LED displays are proof that technology and innovation can advance extremely fast.