LED 101 – THE BASICS OF LED TECHNOLOGY
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
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
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.
LEDs, being based on semiconductor technology, just like
computer processors, are increasing in brightness, energy
efficiency and longevity in a way that's reminiscent of the
way each year's new crop of processors is faster and cheaper
than last year's.
Cree 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.