| |
| Why LED? |
|
| Light-emitting diode (LED) is an electronic light source. The LED was first invented in Russia in the 1920s, and introduced in America as a practical electronic component in 1962. Oleg Vladimirovich Losev was a radio technician who noticed that diodes used in radio receivers emitted light when current was passed through them. In 1927, he published details in a Russian journal of the first ever LED. |
| |
| All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness. |
| |
| LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm 2) with integrated optical components to shape its radiation pattern and assist in reflection. |
| |
| |
 |
| |
| |
| Advantages of LED |
| |
| LED lighting saves electricity |
| |
| The lighting efficiency of the new high power LED light bulbs is more than eight times that of incandescent lights, and twice as high as compact fluorescent lights. LED bulbs also emit a much higher percentage of light in the desired direction. This makes them even more efficient compared to either incandescent or fluorescent for task lighting, desk lamps, reading lights, spotlights, flood lights, and track lighting. |
| |
| With colored LED lights there is simply no comparison. All of the light output from LED bulbs can be a specific color. With other light sources, much of the light produced consists of unwanted colors which are filtered out. This wastes energy. LED lights produce pure color (monochromatic light) which requires no filtering.
|
| |
| LED lights also generate very little unwanted heat. The energy savings may be doubled in air-conditioned environments where each watt of incandescent lighting can add another watt or more to the power needed for air conditioning |
| |
| |
| LED lighting instantly acheives full brightness with no warm up time |
| |
| Fluorescent lights are dim when first turned on, and get brighter as they warm up. Depending on the temperature and the age of the lamp, they can take a long time to warm up. If it is cold enough they will not warm up at all. LED lights always start at full brightness. |
| |
| |
| LED lighting does not contain mercury.
|
| |
| Fluorescent lights contain mercury and must be treated as hazardous waste. LED lighting contains no mercury or other dangerous substances.
|
| |
| |
| LED lighting does not produce any ultraviolet (UV) light
|
| |
| LED lights emit no damaging ultraviolet light, so they will not cause fading and aging of artwork or other sensitive materials. Fluorescent and halogen lights can cause significant damage over time.
|
| |
| |
| LED lighting saves on bulb replacement
|
| |
| LED bulbs can operate for 50,000 hours or more. One LED lightbulb can easily outlast 30 incandescent bulbs, or 6 compact fluorescents! LED bulbs cost less than the bulbs they replace. Operating 8 hours per day, LED light bulbs can last 10 years or more!
|
| |
| LED light bulbs are less sensitive to shock, vibration, and the extreme temperature changes that can quickly ruin fragile incandescent bulbs. And unlike fluorescent bulbs which wear out much faster if they are frequently turned on and off, LED bulbs are not affected by frequent on-off switching.
|
| |
| The long life of LED light bulbs reduce the time, effort and cost of replacement.
|
| |
| |
| LED lighting increases safety and security.
|
| |
| The high reliability of LED lights increases safety and security. There is no waiting for LED light bulbs to warm up. LED bulbs light up instantly at full brightness, even in the coldest weather.
|
| |
| |
| LED lights are safer.
|
| |
| LED bulbs operate at much lower temperatures. Halogen and incandescent lights are hot enough to cause fire, and they frequently do.
|
| |
| |
| And finally...
|
| |
| LED is much easier to spell than either incandescent or fluorescent.
|
| |
|
