Over the last 40 years advancements in LED technology have launched
this light source into a resource bright enough to illuminate any application.
Understanding the basics is simple. Most of the LEDs used in the lighting industry
are comprised of a base, a diode, and a protective lens.
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| LED technology for lighting |
The main difference is the diode in an LED is very esilient. It's
made of a solid crystal which makes it more rugged. This characteristic is why
LEDs are a solid state lighting source and also explain why they can be used in
a number of applications that a traditional lighting sources cannot.
The last major aspect of how an LED works relates to heat. Contrary
to what most people think, LEDs do give off heat. Instead of the heat radiating
from the front of the light source like an incandescent or fluorescent lamp, an
LED dissipates the heat backwards, through the base and PC board.
That is why many LED fixtures have large heat sinks connected to the
back of the PC board. LEDs will soon become the preferred light source over
traditional sources. For starters, LEDs operate using very low wattage but
still provide the same amount of light as traditional sources.
Today LEDs are up to 80 percent more efficient than incandescent lamps
and up to 30 percent more efficient than fluorescent lamps. LEDs are a more
durable light source that don't have fragile filaments and therefore don't
break simply.
Not only are LEDs more rugged but when paired with a well designed
fixture, LEDs are made to last for about 50,000 hours over the life of the
fixture. In most cases these benefits combined to give LED light fixtures a
better overall total cost of ownership over conventional lighting systems.
Over the life span of their system, LED systems will cost less and
save more energy than incandescent and CFL systems. There are many LED
manufacturers trying to take advantage of the LED boom.
But not all LEDs are a good quality. There are many cheaply manufactured
LED fixtures out there that are tarnishing the industry's reputation by
providing sub par performance.
There are several technical differences that can affect an LED
fixtures performance. Two of the most critical are the fixture design and the
quality of LEDs utilized in the fixtures.
For example, some of the fixtures have a white and even bluish tint,
while others look yellow. Even though all the fixtures shown are the exact same
product, their color temperature is drastically different.
A low quality spec was chosen for this LED fixture. LED binning is a
major concern for lighting manufacturers designing fixtures around LEDs. It's
the process by which LED manufacturers group LEDs together in bins by quality
and consistency of critical performance attributes such as light output, color
and power consumption.
The binning exercise allows for consistency in color from one LED to
another and consistency from one fixture to the next in a complete application.
To understand binning, it is necessary to know a little bit about how LEDs are
manufactured.
First the diode crystal is grown in a giant wafer. This giant wafer
is then cut into smaller pieces which eventually are used in the diode
component of the LED. Even though all pieces are cut from a single wafer, are
made from the similar material, they are not all the similar.
A piece cut from one end of the wafer might have a different lumen
output and a different color than a piece that is cut from the other end of the
wafer.
This is why buying LED fixtures from a reputable manufacturer that uses
a narrow binning spec is so dangerous.
It is also important to understand that while a smaller binning spec
increases the quality and consistency of the light emitted, it also increases
the cost of the fixture. Rest assured
But if further validation is desired before buying a fixture, take a
look at the fixtures lighting facts label. Lighting facts are similar to a
nutrition facts label but apply to lighting fixtures.
Lighting facts outlines the
light output of a fixture in lumens, the watts used and the efficacy of the
fixture in lumens for each watt. The color quality is also listed as a number 0
through 100 on the CRI or color rendering index scale.
The closer the number is to 100, the better the color accuracy.
Lighting facts also list the CCT or correlated color temperature. This scale
ranges from 2700 degrees Kelvin which is a warm yellowish color to 6500 degrees
Kelvin, which is a cool white or almost blue color.
Additionally buyers should look for a LM-79 testing report to
validate an LED fixtures lumen output. Never buy an LED fixture if its lumen
output, color temperature, or else color accuracy cannot be validated before
the purchase.
this is which i know about LED technology for lighting.