LED Bulbs & Lamps
An LED bulb and lamps are light-emitting diode (LED) product that is assembled into a light bulb & lamps for use in lighting fixtures. LED luminaries have a lifespan and electrical efficiency that is multiple times higher than incandescent lamps, and significantly better than most compact fluorescent lamps, with some chips able to emit more than 100 lumens per watt. The LED lamp market is projected to grow more than 12-fold over the next decade, from $2 billion today to $25 billion in 2023, which is a compound annual growth rate of 25%.
Like incandescent lamps and unlike most fluorescent lamps (e.g. tubes and CFL), LED lights come to full brightness without need for a warm-up time; the life of fluorescent lighting is also reduced by frequent switching on and off. Initial cost of LED is usually higher. Degradation of LED dye and packaging materials reduces light output to some extent over time.
With research into organic LEDs and polymer LEDs , cost per lumen and output per device have been improving rapidly according to what has been called Haitz’s law, analogous to Moore’s law for semiconductor devices.
Some LED lamps are made to be a directly compatible drop-in replacement for incandescent or fluorescent lamps. An LED lamp packaging may show the lumen output, power consumption in watts, color temperature in kelvins or description (e.g. “warm white”) and sometimes the equivalent wattage of an incandescent lamp of similar luminous output.
LEDs do not emit light in all directions, and their directional characteristics affect the design of lamps. The light output of single LEDs is less than that of incandescent and compact fluorescent lamps; in most applications multiple LEDs are used to form a lamp, although high-power versions are becoming available.
LED chips need controlled DC electrical power; an appropriate power supply is needed. LEDs are adversely affected by high temperature, so LED lamps typically include heat dissipation elements such as heat sinks and cooling fins.