![]() The first high-brightness blue LED was demonstrated by Shuji Nakamura of Nichia Corporation in 1994. However, early LED lamps were inefficient and could only display deep red colors, making them unsuitable for general lighting and restricting their usage to numeric displays and indicator lights. Pighini, and Monsanto Company's LED indicator lamp. In 1968, the first commercial LED lamps were introduced: Hewlett-Packard's LED display, which was developed under Howard C. The first low-powered LEDs were developed in the early 1960s, and only produced light in the low, red frequencies of the spectrum. The increasing scarcity of energy resources, and the environmental costs of producing energy, particularly the discovery of global warming due to carbon dioxide emitted by the burning of fossil fuels, which are the largest source of energy for electric power generation, created an increased incentive to develop more energy-efficient electric lights. ![]() ![]() Lighting consumes roughly 12% of electrical energy produced by industrialized countries. Global electric lighting in 1997 consumed 2016 terawatthours of energy. Like fluorescents, they also contain hazardous mercury.Ĭonsidered as electric energy converters, all these existing lamps are inefficient, emitting more of their input energy as waste heat than as visible light. These were the most efficient white electric lights before LEDs, having a luminous efficacy of 75–100 lumens/W and have a relatively long bulb lifetime of 6,000–15,000 hours, but because they require a 5–7 minute warmup period before turning on, are not used for residential lighting, but for commercial and industrial wide area lighting, and outdoor security lights and streetlights. Metal-halide lamps, which produce light by an arc between two electrodes in an atmosphere of argon, mercury and other metals, and iodine or bromine.However, their mercury content makes them a hazard to the environment, and they have to be disposed of as hazardous waste. These are more efficient than incandescent lights, having a luminous efficacy of around 60 lumens/W, and have a longer lifetime 6,000–15,000 hours, and are widely used for residential and office lighting. Fluorescent lamps, which produce ultraviolet light by a glow discharge between two electrodes in a low pressure tube of mercury vapor, which is converted to visible light by a fluorescent coating on the inside of the tube.Incandescent lamps produce a continuous black body spectrum of light similar to sunlight, and so produce high Color rendering index (CRI). They are being phased out of general lighting applications. These are very inefficient, having a luminous efficacy of 10–17 lumens/W, and also have a short lifetime of 1000 hours. Incandescent lights, which produce light with a glowing filament heated by electric current.Illustration of Haitz's law, showing improvement in light output per LED over time, with a logarithmic scale on the vertical axisīefore the introduction of LED lamps, three types of lamps were used for the bulk of general (white) lighting: The text on retail LED lamp packaging may show the light output in lumen, the power consumption in watts, the color temperature in Kelvin or a color description such as "warm white", "cool white" or "daylight", the operating temperature range, and sometimes the equivalent wattage of an incandescent lamp delivering the same output in lumen. LED lamps may use multiple LED packages for improved light dispersal, heat dissipation, and overall cost. Some LED lamps are drop-in replacements for incandescent or fluorescent lamps. Light output decreases gradually over the lifetime of the LED (see Efficiency droop section). Frequent switching on and off does not reduce life expectancy as with fluorescent lighting. LEDs come to full brightness immediately with no warm-up delay. The LED lamp market is projected to grow from US$75.8 billion in 2020 and increasing to US$160 billion in 2026. Generally the current waveform contains some amount of distortion, depending on the luminaires’ technology. The driver circuit may require special features to be compatible with lamp dimmers intended for use on incandescent lamps. LED lamps require an electronic LED driver circuit to operate from mains power lines, and losses from this circuit means that the efficiency of the lamp is lower than the efficiency of the LED chips it uses. Commercial LED lamps have a lifespan many times longer than incandescent lamps. The most efficient commercially available LED lamps have efficiencies of 200 lumen per watt (Lm/W). LED lamps are significantly more energy-efficient than equivalent incandescent lampsĪnd can be significantly more efficient than most fluorescent lamps. An 80W Chips on board (COB) LED module from an industrial light luminaire, thermally bonded to the heat sinkĪn LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs).
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