How LEDs Produce Tunable White Light
Colour Tuning Conventional Method:
The conventional approach to colour tuning in white light fixtures and typically combines cool and warm white LEDs which can be individually controlled like the red, green, and blue LEDs in a full-colour LED device. Adjusting the relative intensities of the warm and cool LEDs changes the colour temperature in a tuneable white device, just as adjusting the relative intensities of the red, green, and blue LEDs changes the colour in a full-colour device. This method is limited to efficiency and colour rendering of fixed white phosphor based solutions. (Typical CRI Ra70-85, Typical R9 – 11-20).
The luminous intensity fluctuates across the tuning range as the module dims from one CCT to another. Colour shift using this method has the same causes as fixed white solutions using the same LEDs. Because colour shift is increased by current,(current adjustment required to vary the luminous flux of the different coloured LEDs to achieve the colour change) it does not tune accurately to the black body locus (required to truly emulate conventional light sources).
ChromaWhite™ VCCT Colour Tuning Method:
ChromaWhite™ VCCT is an advanced colour mix technology that monitors and adjusts the colour of the delivered light using ColourLoc active feedback technology. This enable CCTs at points along the black body locus to an accuracy of <3 Macadam ellipse. The CCT across the range is acurately met regardless of the effects of aging, operating temperature or current (usually for dimming).
LumenLoc technology actively monitors and corrects the delivered luminous flux and ensures that luminous intensity remains consistent across the tuning range.
The spectral density is closer to daylight (but does not emit UV or IR). The colour rendering matches or exceeds popular conventional sources such as tungsten halogen, peaking at Ra97. Colour rendering is excellent in pastel and saturated shades as well as skin tones. The challenging saturated reds (R9) is typically greater than 90.