"Edison was the 38th inventor of a filament based lamp. Edison was the 1st to deliver the entire lighting system." - Roland Haitz (Retired from Agilent), founder of Haitz's Law the LED equivalent to Moore's Law of computing.

What is SSL?

SSL is a fundamental shift in the technology of lighting, an industry that has seen very little change since it began in the 19th century. This shift can be compared to:

What's the Big Deal?

SSL is tomorrow's lighting because of the convergence of several powerful improvements, each a significant development in and of itself, which when combined together become a method for creating light that will change the industry.

Advantages of Solid State Lighting

Energy Efficiency: LEDs have the potential to achieve 90%+ conversion efficiencies as a light source compared to under 50% for conventional sources (a common household light bulb is approximately 9% efficient). Because they are able to convert electricity directly into light, for the first time in history, LEDs offer the promise of producing more light than heat from the energy supplied. This has huge implications for energy savings on a global scale in the future. Already, white LEDs are more efficient (measured in lumens/watt - lm/W) than incandescent sources. Today in applications where color is required, traffic signals or corporate signage for example, SSL is showing substantial reductions in energy consumption as all of the light produced is used, not wasted.

Long Life: The second advantage of LEDs that is revolutionizing the lighting industry is the extremely long life that can be achieved. There are two parts to this story.

The first part is referred to as the "useful life", which is application specific. Common understanding is that a lamp lasts a certain amount of time and then goes out. Over the life of the lamp, the light output decreases and eventually the lamp comes to the "end" of its life. LEDs slowly decrease in light output over time as well, however, they never actually reach an "end" to their life in practical terms. What is important to consider is how long the LEDs will provide enough light to perform their duty, in other words: what is their useful life? For some applications this may be in excess of 100,000 hours where the light level is not critical. For others, it may be 50,000 hours, still approximately 4x better than a common fluorescent and 20x better than a household incandescent lamp.

The second part of the story is that there is no practical end to the life of LEDs. This has important implications for decorative architectural applications and corporate imaging programs. While a burned out lamp can have a damaging impact on aesthetics, the gradual dimming that will occur beyond the useful life of an LED-based system will not have the dramatic negative effect and will not require immediate maintenance.

Robustness: There is no glass to get broken and no filament to break. LED lighting systems are inherently resistant to vibration problems and can be designed to withstand almost any extreme environment more easily than traditional lighting.

Low Temperature Performance: While there are lamps available that are resistant to low temperatures (metal halide, HPS), others, in particular fluorescent, do not perform well in cold weather. LEDs actually operate more efficiently in colder environments than at room temperature.

Digital Control: As the world goes digital it becomes increasingly important that lighting become integrated into that world. SSL is already a digital system that can be interfaced with other systems or precisely controlled to achieve maximum performance.

Color Saturation and Spectrum: It is possible to program an RGB array to produce almost any color and because light is not being filtered or absorbed the result is a deeper saturation of the color. This also applies to individual LED colors such as red which is produced directly and not by filtering out all of the blue, green, and yellow present in the light source.

Optical Control: The size of an LED is very small and the light rays it produces are emitted in a very narrow beam. This means that optical systems can be designed to control the light with extremely high efficiency, resulting in less light being required to perform a certain function, which in turn increases the energy efficiency of the system.

Low Voltage Operation: Current SSL systems generally operate on low voltage DC power, making them very safe to install and operate.  

It's More Than Just LEDs.

• Light Emitting Diode (LED) = a light source
• Solid State Lighting (SSL) = a fully integrated system to deliver light

The Foundations or "Enabling Technologies"

Power Conversion: Efficient conversion from "wall plug" electricity to safe, low voltage DC current.

Control & Drive: Electronics that tell the LEDs what to do.

Communication: The ability to use a computer, PDA, building control, or other device to talk to the lighting.

Thermal Management: Your computer has a fan in it for a reason. The key to maximizing LED performance lies in keeping them cool.

Optics: Putting the light where it is needed is essential for an efficient lighting system.

The Source: Light Emitting Diodes (LEDs) - an efficient, ideally sized electronic light source that converts electricity directly into light.