Inspired by the color tuning function of King Blade X (an electronic glow stick), this paper investigates different approaches of LED color tuning, including dim-to warm tuning, white color tuning, and full color tuning. This paper would go over their operating principles, advantage and withdraws, and potential applications.
Introduction
The interest to investigate LED color tuning originated from my King Blade. This is an electronic glow stick used in live concerts. One of its remarkable feature is the color tuning function with its app on smart phones. One could adjust the color and the intensity by simply set the RGBW values. One can even set a series of colors and use the buttons below the stick to switch between them. figure.1 …show more content…
In a nutshell, this process is to change the light from a cold, white/blue color to a warm yellow/amber color. On incandescent sources, dim-to-warm tuning can be done easily by varying the current through the filament, changing its actual temperature, and therefore change the CCT of the light. To imitate the behavior of incandescent light sources, LED sources would vary the CCT to produce the same color temperature of our familiar light sources. figure 4. dim-to-warm CCT curve
Potential issues
• The CCT change goes with the color change (for example, to change from a warm color to a cool one, the color will change from yellow/orange to white). In cases that the users do not want a color change, white tuning will be a better choice.
• Some dim-to-warm tuning products use white LEDs along with amber LEDs for warm colors. At the low end of dimming range, only the amber LEDs are producing light. This could make the room finishes appears weird.
• Low efficiency compared to non-tunable white LEDs.
White …show more content…
examples of white-tuning
Potential issues
• The wiring could be complex because the controllers of intensity and CCT are separate.
• Low efficiency compared to non-tunable white LEDs.
Full-color tuning
Also referred to as RGB, RGBA, RGBW, spectrally tunable and “color changing”, full-color tunable products often consist of 3 or more LED sets. The individual LEDs can be narrow-band LEDs (producing a “pure” color, usually RGB), or coated LEDs. The monochromatic LEDs are usually red, green and blue (the primary colors of light, RGB), and can be augmented with amber (A) and white (W). The King Blade is a typical RGBW full-color tuning product. Full-color tuning is being used to create theatrical effects in live concerts, parties, theatres, and commercial spaces.
Potential issues
• There are more than one way to create light of a specific CCT from 3 or more LED sets, therefore the products from different manufacturers may not produce exactly the same result.
• Lowest efficiency in the 3 tuning approaches. The limiting factor is the efficiency of the green LED, which is much lower than white LEDs.
Color and materials color Wavelength(nm) Typical