Traditional incandescent light bulbs rely on a filament being heated to produce light and heat mixed together in IR (infrared). Fluorescent tubes compact fluorescent lighting and almost all of the high intensity discharge lamps such as; high-pressure sodium, mercury vapor, metal halide and others all rely on mercury to produce intense ultraviolet light. (Converted to visible light with phosphor)
The proliferation of mercury in the environment has caused global concern, with the World Health Organization, declaring mercury one of the top five toxins of concern. Unfortunately many of these mercury laced products never make it to the reclamation centers, with the
“Association of Lighting and Mercury Recyclers” stating “what we do know is that 500 million+ of these (CFLs) bulbs are placed in some type of open container and treated as municipal waste”
For years governments and utility companies have pushed compact fluorescence on consumers while failing to build up appropriate reclamation centers and are now attaching eco-fees on florescent and LED products (starting in British Columbia in August 2012)
It won't be long before you will have to pay extra to purchase/dispose of mercury laced lighting products especially if you're a business or company changing thousands of florescent lights and tubes. Many governments are implementing, or already have implemented ”Eco-fees”
LED is a crystal-based lighting technology
LED differs from other types of lighting technology in the fact it has no moving parts, it has no filament and no mercury vapor is ignited.
The particular crystal that emits light is gallium nitrate, although discovered almost 100 years ago, the technology to grow gallium crystals pure enough, and in the right orientation has not been available until recently.
Light emitting diodes come in several different packages
DIP (duel in-line pin) LEDs are the most commonly recognized type of LED, their bullet shaped plastic enclosure houses a tiny gallium nitrate crystal, even more recognizable are the Cathode and anoid wires extending out the back. They are easily soldered into place on circuit boards, usually have a limited light output.
SMD surface mount diodes, these miniature ceramic squares contain gallium nitrate crystals bonded to phosphorus coatings, extremely low profile of 1 mm or less than many times the light output of the IP LED. Screw in retrofit LED bulbs with massive arrays of SMD's are sometimes referred to as corn lights.
HB LED or high brightness LEDs; (sometimes referred to as spider LEDs )depending on the brand and chipset these 1 to 7 W super-bright LEDs have amazing outputs, up to and above 150 lm per watt. These types of LEDs require special attention to thermal management, secondary heat sinks or cooling systems are required to achieve maximum lifespan.
COB chips on board
One of the newer LED technologies currently available is “Chip-on-board” technology. Well other types of LED light engines must be mounted to electronics and heat sinks creating thermal resistance barriers, chip onboard technology bonds gallium nitrate crystals and wires directly to aluminum substrates. These dense clusters of LED chips are then covered with a phosphorus disc to produce desired color temperature.
Advancements of super substrates
One key to the efficiency of LED lays in the substrate; different manufacturers have been experimenting with different compounds to achieve larger crystals and more cost-effective production techniques.
These include but are not limited to; Gallium on silicone, gallium on gallium, gallium on glass, gallium on silicon carbide.While other lighting technologies have stalled, LED continues to lead the pack in energy efficiency and luminance output per watt. Color temperature and brightness issues have been resolved and the costs continue to decrease rapidly insuring LEDs eventual dominance.It is conceivable, in the future we will eliminate Mercury from ALL lighting products. Protecting the environment from toxic contamination should always be a top priority.