LEDs Are Still Popular (and Improving) after All These Years - AN1883

Maxim > App Notes > Automotive Keywords: LED, PDP, plasma display panels, OLED, Organic LEDs, PLED, Polymer LEDs, LCD, TFT, VFD, vacuum Feb 25, 2003 fluorescent displays, Nixie, Lumens, Candelas, CIE, CRT, GaAsP, GaP APPLICATION NOTE 1883LEDs Are Still Popular (and Improving) after All These Years Abstract: This article reviews LED display technology that has rapidly changed over its 35 years. The origins of LEDs and their traditional applications are discussed. Some new applications for the improved technology are presented. IntroductionIn recent years, countless articles have focused on new display technologies. Typical topics have covered: the explosion of TFT color LCD panels with ever-increasing size into laptops and flat-screen monitors; PDP (plasma display panels) for high-definition TV CRT replacement; polymer LED (PLED) or organic LED (OLED) displays for the small color displays in games, cell phones, and PDAs. This article discusses a 35-year-old display technology that itself has rapidly changed—the LED. This overview covers the origins of LEDs, their traditional applications, and how improvements in the technology have stimulated new applications. A Brief History of LEDsCommercial research into LED technology started in 1962, notably at Bell Labs, Hewlett-Packard® (HP®), IBM®, Monsanto®, and RCA®. Work on gallium arsenide phosphide (GaAsP) led HP and Monsanto to introduce the first commercial 655nm red LEDs in 1968. In 1971 HP ...