LED stands for light-emitting diode. LEDs are small light sources that become illuminated by the movement of electrons through a semiconductor material. LEDs can be integrated into all sorts of products to provide white and colored light, such as flashlights, light bulbs, and integrated light fixtures.
LEDs used to draw attention to something, such as an exit sign,
LEDs used to illuminate an area. ENERGY STAR qualified LED lighting uses multiple illuminator LEDs inside a fixture to produce white light.
Many tiny LEDs are used in
LEDs are part of a family of lighting technologies called Solid-State lighting. This family also includes OLEDs (Organic Light Emitting Diodes). OLEDs (pronounced OH-leds) consist of sheets of carbon-based compounds that glow when a current is applied through transparent electrodes. While not yet market ready, OLEDs will function like a thin film on a wall or ceiling that illuminates a room. Like LEDs, OLED technology is advancing rapidly.
Solid-State lighting (SSL), most commonly seen in the form of Light Emitting Diodes (LEDs), has the potential to revolutionize the efficiency, appearance, and quality of lighting as we know it.
The U.S. Department of Energy estimates that rapid adoption of LED lighting in the U.S. by 2027 could;
LEDs emit light in a specific direction, whereas an incandescent or fluorescent bulb emits light — and heat — in all directions. For direct lighting applications LED lighting uses both light and energy more efficiently.
For example, an incandescent or compact fluorescent (CFL) bulb inside of a recessed can will waste about half of the light that it produces, while a recessed down light with LEDs only produces light where it’s needed — in the room below.
Incandescent bulbs create light by passing electricity through a metal filament until it becomes so hot that it glows. Incandescent bulbs release 90% of their energy as heat.
In a CFL, an electric current is driven through a tube containing gases. This reaction produces ultraviolet light that gets transformed into visible light by the fluorescent coating (called phosphor) on the inside of the tube.
LED lighting products use light emitting diodes to produce light very efficiently. The movement of electrons through a semiconductor material illuminates the tiny light sources we call LEDs. A small amount of heat is released backwards, into a heat sink, in a well-designed product; LEDs are basically cool to the touch.
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LED lighting, when designed well, can be more efficient, durable, versatile and longer lasting than incandescent and fluorescents lighting.
LED lighting starts with a tiny chip (most commonly about one square millimeter) comprised of layers of semi-conducting material. LED packages may contain just one chip or multiple chips, mounted on heat-conducting material called a heat sink and usually enclosed in a lens. The resulting device, typically around 7 to 9 mm on a side, can be used separately or in arrays. LED devices are mounted on a circuit board, which can be programmed to include lighting controls such as dimming, light sensing and pre-set timing. The circuit board is mounted on another heat sink to manage the heat from all the LEDs in the array. The system is then encased in a lighting fixture, architectural structure, or even a light bulb package.Back to top
After less than a year of use, a poorly designed LED product can flicker, shift in color, look dim, offer uneven light, or continue to use power when turned off, among other problems.
Not necessarily. LEDs have been efficient and long lasting as indicator lights in electronics for years, but using LEDs to create stable white light for general lighting presents new challenges. The key to success is smart design. To qualify for ENERGY STAR, LED lighting products must pass a variety of tests to prove that the products will display the following characteristics:
Bad design can lead to a wide range of problems, some immediately observable and some not. Poorly designed products often come with exaggerated claims while failing to deliver on the quality specifications above.
ENERGY STAR is known for advancing efficiency, but is equally strong on overall product quality since the specifications for LED products include: