The ability to control the color of white light or “tunable CCT”, makes LED the ultimate light source
The different colors of white light
As our sun travels across the sky, the “Color Temperature” goes through a wide range blues and reds, with the low end being the warm reds (2500k), finishing with icy blues (10,000k)
With the emergence of LED lighting, manufacturers and distributors found they had to inform customers of options that they had never heard of, such as color temperature and lumens per watt. Color temperature is something most people are completely unaware of except that they may not like the bluish color of fluorescent lights, or the greenish hue from CFL's.
The benefits of being able to control color temperature
New Tunable COB (Chip on Board) LED from Sharp Electronics
The Tiger Zenigata LED array has stripes of different phosphors, providing a small-form-factor LED source with tunable color temperature.
Warm blooded mammals bodies operate on a 24-hour clock, after millions of years of evolution without artificial lighting, our bodies have gotten used to the color temperature changes that naturally occur through our day-to-day lives. During the day the color temperature fluctuates between 2000 , to well over 10,000° k, and as the sun sets the color temperature drops, signaling our bodies begin to wind down and prepare to sleep through the coming night. There are continuing studies underway involving schools and seniors centers, where color temperatures are slowly adjusted throughout the day, mimicking a more natural lighting pattern. In fact Phillips researchers found that; School children after recess exposed to a low temperature; 2700 degrees Kelvin, helped calm and relax them, 5000 to 6000°k seems to be the commonly acknowledged working range, where human productivity is maximized.
Blue light spectrum can interfere with natural sleep patterns
For the same reason these higher temperatures keep us productive, they can also interfere with our ability to produce serotonin and other biological activators that trigger human sleeping patterns. (Serotonin production) In most senior centers, nearly 100% of the lighting is fluorescent with color temperatures around 4000k or higher being standard. Being exposed to these higher (blue) spectrums in the evenings, the body's natural clock can be thrown off, and for seniors and other sensitive individuals this can lead to various sleep disorders.
Rule of thumb: Avoid light levels over 3000k in the hours before your sleep cycle and try to remove or block any (even the smallest) light source.
Color corrected LEDs benefit our animal friends as well
LED lighting installations in dairy, poultry and pork production facilities have had positive benefits for the animals, in turn leading to increased production. With no UV, LED lighting offers a “Non-tissue damaging” illumination source. The color temperature of the LED simulates natural lighting much more efficiently and with more “tune-ability” than other high output light sources.
New LED Lighting controllers allow manual or automatic control not just dimmable, but a sliding scale between sunrise and sunset color temperatures. Some of these “Next Gen” products “Sense” the ambient light in the room and intelligently respond, if the user is requesting “full brightness” and sensors detect ambient sunlight, the fixture will come to full 7000k to match ambient light. However, a user requesting increased levels in a dark room will respond with 2500-3000k
These new features may help LED reach the tipping point over florescent light alternatives.
New electronic florescent lighting is very cost competitive with LED, with tube and fixture prices that can look more attractive to retrofitters and are still being promoted by energy companies over LED. As these new “Tunable” LED systems become widely available and their benefits known, they will offer a true alternative to mercury based florescent lighting.