Solid State LED Technology 

The very latest generation of high brightness LED light sources, particularly compact LED Arrays, are today's amazing planet friendly & highly energy efficient alternatives  to  essentially 100+ year old lighting technology: the incandescent bulb and the florescent tube.

Though LED lighting was originally made viable in 1962 by Nick Holonyak, Jr., it wasn't until the mid 2000's when brightness level and quality of white light LEDs was achieved.  This allowed them to effectively compete with "bubs" and "tubes".

And today, though generally 20-60% higher in initial purchase cost, high brightness LED based luminaires are now the best choice for many, if not most, exterior and interior  applications. This is namely true for:

• The quality of light generated
• 10-20 year useful lifespan and inherent ruggedness
• Extremely low energy consumption
• Minimal net-total impact on the environment

To learn more why the LED is now considered such a revolutionary light source , see below its key advantages, technical highlights, and the basic physics of light-emitting semiconductors.

Visual impact, or lack of it, is directly proportional to the light source's effect onto the area viewed (illuminance) and the extent of perceived color accuracy being brought back to the eye from the target -i.e. the "makes everything look great" element.

Traditionally the Color Rendering Index (CRI) has been the internationally recognized measurement of color accuracy of a light source. Using this measurement LED's typically receive scores of between 80-90 (out of 100) which would lead one to believe that the quality of light produced is just "OK".

In reality however, subjective tests have repeatedly shown that people really like what they see with LED light, and in many cases better than when viewed using incandescent and fluorescent sources. It is hypothesized that the most likely reason is that color of objects appear more vivid to the human eye when using solid state generated light.

LEDs today have an expected useful life of around 50,000 hours, or 25 years of normal usage. When compared to an incandescent light source of equivalent output, it will continue functioning near on average 50 times longer --that is HUGE! But like everything in life there are some significant caveats to that longevity.

The first being is that LED chips must be integrated to a well designed LED thermal management system (heat sink and/or fan) or premature failure is virtually guaranteed. Though visible lighting LEDs produce no infrared radiation (IR) so they are cool to the touch, they do produce heat. In fact, approximately only 25% of the electrical power applied to an LED results in visible light. The remaining 75% is converted to heat --not scorching heat like in an Edison type light bulb, but heat nevertheless. And this heat must be efficiently drawn away from the LED chip itself (the "junction") or the theoretical maximum life span will not be achieved.

A second determining factor is the design and quality of the "driver" --the essential component that tightly controls the amount of electrical current flow to the LED itself-- plus all associated and needed electronics (i.e. capacitor, DC power supply that converts AC power to DC power, etc.)

If any of these components have MTBF hour ratings lower than the LED chip itself, then system failure will happen earlier than stated specifications. Yes these components can be replaced, but generally for most luminaire designs, the time and effort required to do so would not be cost justified.

As for ruggedness, since LEDs produce light without glass parts, filament, or special gas, short of physical destruction of its circuit board no amount movement or jarring will stop it from functioning.

Thus if a LED lighting luminaire's design approach is taken as a whole system with performance determined only by the sum-of-its-parts, this light producing technology will last years longer than any other source available today.

LED's today, whether in a "bulb" type package or in a light fixture, produce 90 to 120 lumens (measurement of the total amount of visible light) per watt (electrical power consumed) --that is over 80% better than an incandescent bulb. This makes them today the most efficient light source for directional applications and slightly better than linear fluorescent and HID lamps for flood or light-everywhere applications.

Currently, projections for to be commercially available warm white light LED technology (the type most used for general lighting) will reach 150 lumens per watt efficiency by 2015 --and as high has 200 lumens per watt efficiency for mixed color. Predictions are that when those efficiency levels are reached, most popular light sources used today will be outclassed and will likely be displaced from the market.

In a 2012 US Department of Energy funded study it compared the total environmental impact of incandescent, fluorescent, and LED lighting sources. After comprehensive analysis it found that LED was the clear winner. The total impact measurement was derived by:

• The amount of energy needed to be produced in order to create light --PLUS
• Energy and resources consumed in the manufacturing process of the luminaire's components --PLUS
• Its post life disposal effects on the environment

As expected, the degree of negative impact from incandescent lighting was found to be extensive and far more than LED. For fluorescent, the impact was less significant but still greater than LED light sources.

And looking forward into the future, the study concluded by taking into account predicable and inevitable manufacturing process improvements (see Haitz's law ), LED lighting becomes, environmentally speaking, the clear winner.