SSL (solid-state lighting) 101

The demise of the incandescent light bulb

Not so long ago, one did not have to put too much thought into purchasing a light bulb. The only decision you had other than the shape of the light bulb and base was the wattage. 40-60 or 100 W were pretty much your only option, okay some were frosted glass and some were clear, but the real distinction was in the brand names. It is a tough choice for consumer to make the decision to purchase the generic or the name brand, even with a large price gap. The generic bulbs were great in a pinch, even though most seem to burn out after less than 100 hours. Just like anything, you get what you pay for.

Remaining almost unchanged for over 100 years, Thomas Edison's incandescent light bulb remains one of the most important inventions in human history. Light has brought safety to our streets, productivity to our factories and allowed mankind to work in the bowels of the earth, even grow vegetables were otherwise would be impossible.


Once seen as the universal symbol for the brilliant idea, the light bulb image is now becoming the symbol of wasteful inefficiency. This is largely due to the fact that light bulbs convert only 10% of the energy used, to light energy, the other 90% is converted into heat. In colder climates may seem favorable, however the light bulb is also an extremely inefficient heater, which would you rather have heating your freezing cold house:  11-100 W lights or a thousand watt energy efficient ceramic heater!


The Dawn of SSL


Although LEDs have been around since the 60s it has only been in the last 10 years advancements have turned the LED (light emitting diode) into the solid-state lighting champion it has become. The last few years has now seen LED technology pass from encapsulated LED to surface mounted diode (SMD). These are the literally wafers of nano crystals, grown in precisely controlled crystal growing chambers. Recently, manufacturers of these amazing SMD light engines have shown capabilities of growing SMD LEDs with up to 30 cm diameter.


Although encapsulated LEDs are still in use today, SMD appears to be the jewel of the high brightness category. The best of the best are now achieving 100 lm for every watt of electricity used. Nominal output from a 60 watt incandescent is 740 lumens according to the GE lamp catalog (12.3 lm per watt)


5 mm encapsulated LEDs




Incredibly, the newest high brightness LEDs are outputting 8-10 times as much light as their incandescent counterparts. Imagine being able to reduce your lighting consumption to 10% of what it is today, now imagine the entire country reducing its lighting consumption by 90%! North American governments have recently looked at this possibility and amazingly the US Department of Energy predicts complete SSL conversion by 2020, that's everything from street lights, parking structures, office buildings, government buildings, almost every light you currently see or use is doomed to be replaced by solid-state lighting technology in just a few short years.

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