LEDs 101 | Vista Manufacturing, Inc.

LEDs 101

Light emitting diodes (LEDs) are solid-state lighting components. They have no moving, fragile parts and can last for decades. LEDs can be many times more energy efficient than light bulbs, depending on the application. Just as vacuum tubes in televisions were replaced with solid-state components, the last remaining vacuum tube light bulbs are being replaced by solid-state components.

Imagine a grain of sand that emits a very bright light, usually red, amber, green or blue, depending on the material, when an electrical current is applied. That's essentially an LED. The actual science and manufacturing process to develop an LED is quite complex, but the principle is simple.

The first LEDs for commercial applications were red. They functioned as on/off or indicator lights in electronic devices such as VCRs, calculators, stereo systems and even automobile subsystems. Eventually, LEDs were produced in green and amber as well. The major breakthrough came in 1989 when Cree, Inc. of Durham, NC, started shipping the first commercially viable blue LED, based on silicon carbide. That blue LED enabled white LED-based light. Mixing red, blue and green light produces white light.

Today, a more-efficient and cost-effective white LED light is revolutionizing the lighting world. The white power LED, based on a blue LED chip coated with a phosphor, is bright and efficient enough to be used in general illumination. Fixture manufacturers are making LED-based products for outdoor street, walkway, parking and indoor-down light applications.

Cree, a company whose founders included several N.C. State University graduate students, introduced the first lighting-class white power LED in 2006 and followed up with the first lighting-class warm (softer) white power LED in early 2007. LEDs are ready for general-illumination applications, presenting a dramatically enhanced lighting option to save energy and maintenance costs as well eliminate the hazardous-waste issues associated with mercury-containing light bulbs and tubes.