LEDs, What are they and how do they work?
LED stands for light emitting diode. LED lighting products produce light up to 90% more efficiently than incandescent light bulbs.
An electrical current passes through a microchip, which illuminates the tiny light sources we call LEDs, resulting in visible light. The heat LEDs produce is absorbed into a heat sink, thus preventing performance issues.
Lifetime of LED Lighting Products
The lifespan of LED lighting products is defined differently than that of other light sources, such as incandescent or compact fluorescent lighting (CFL). LEDs typically do not “burn out” or fail. Instead, they experience ‘lumen depreciation’, wherein the brightness of the LED dims slowly over time. Unlike incandescent bulbs, LED “lifetime” is established on a prediction of when the light output decreases by 30 percent.
How are LEDs Used in Lighting
LEDs are incorporated into bulbs and fixtures for general lighting applications. Small in size, LEDs provide unique design opportunities:
- Some LED bulb solutions may resemble familiar light bulbs, while better match the appearance of traditional light bulbs.
- Some LED light fixtures may have LEDs built in as a permanent light source.
- There are also hybrid approaches where a non-traditional “bulb” or replaceable light source format is used and specially designed for a unique fixture.
- LEDs offer a tremendous opportunity for innovation in lighting form factors and fit a wider breadth of applications than traditional lighting technologies.
LEDs and Heat
LEDs use heat sinks to absorb the heat produced by the LED then dissipate it into the surrounding environment. This keeps LEDs from overheating and burning out. Thermal management is the single most important factor in the successful performance of an LED. The higher the temperature at which the LEDs are operated, the more quickly the light will degrade, and the shorter the useful life will be.
LED products use a variety of unique heat sink designs and configurations to manage heat. Today, advancements in materials have allowed manufacturers to design LED bulbs that match the shapes and sizes of traditional incandescent bulbs.
How is LED lighting different than other light sources?
LED lighting differs from incandescent and fluorescent in several ways:
- When designed well, LED lighting is more efficient, versatile, and lasts longer.
- LEDs are “directional” light sources, which means they emit light in a specific direction, unlike incandescent and CFL, which emit light and heat in all directions.
- LEDs are able to use light and energy more efficiently in a multitude of applications. However, it also means that sophisticated engineering is needed to produce an LED light bulb that shines light in every direction.
- Common LED colors include amber, red, green, and blue. To produce white light, different color LEDs are combined or covered with a phosphor material that converts the color of the light to a familiar “white” light used in homes. Phosphor is a yellowish material that covers some LEDs. Colored LEDs are widely used as signal lights and indicator lights, like the power button on a computer.
- In a CFL, an electric current flows between electrodes at each end of a tube containing gases. This reaction produces ultraviolet (UV) light and heat. The UV light is transformed into visible light when it strikes a phosphor coating on the inside of the bulb.
- Incandescent bulbs produce light using electricity to heat a metal filament until it becomes “white” hot or is said to incandesce. As a result, incandescent bulbs release 90% of their energy as heat.