LED Light Bulb

The technology has improved enormously since the 1960s when the first LEDs came to market. LEDs are now the industry standard in a variety of specialty lighting markets, and the popular bulbs are rapidly entering the general illumination market. LED bulbs are more energy efficient and last longer than incandescent, halogen, and fluorescent bulbs, but their up-front costs are higher. Since a fifth of electrical generation goes toward lighting, LEDs hold the potential to greatly reduce energy use. However, energy efficiency rebound effects could partly or entirely offset these savings.
LEDs from the 1960s and 1970s could only emit yellow-green, orange, red, or infrared light. White LEDs, based on blue LED technology, arrived on the market in the 1990s. Early LED designs for general illumination emitted a bluish-white light. Developers worked to improve white LED light quality for general illumination and specialty lighting applications. Subsequently, a more complete spectrum of LED illumination became available to lighting engineers, who then tinkered with the subtleties of "warm" or "cool" white LED output. In the 2000s, LED because standard for aircraft, ship and automotive lighting as well as emergency lighting, and a variety of other specialty lighting applications. In 2010, numerous LED manufactures released bulbs designed for general illumination priced at around $60. Prices have since dropped but up-front cost for the bulbs still poses a barrier to broader LED adoption.