Knowledge How Do Color Changing LED Lights Work?

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Knowledge How Do Color Changing LED Lights Work?

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A color changing LED light is used to provide adjustable-color light throughout a broad gamut area. Color changing LED lights are dynamic lighting systems that may be used as a design tool to adjust for aesthetics, atmospheres, physiological effects, preference, or artistic expression. Color changing LED lights fall in two groups: dynamically changing color lights and color tuning lights. Dynamic lighting fixtures enable an infinite variety and combination of dynamic effects ranging from simple color changing (chasing sequences, sweep, burst, undulations, etc.) to graphics and light shows in which multiple light nodes act in unison. Color tuning lighting systems have the ability to fine-tune the spectral power distribution (SPD) of their output to enhance select areas of the color palette or modulate the color temperature of white light.

Color changing LED lights are commonly designed as RGB (red, blue and green), RGBA (red, blue, green, amber or yellow), RGBW (red, blue, green, and white), or RGBWA (red, blue, green, white, and amber) systems. These systems are constructed in a range of sizes and form factors. Color changing LED light can be either lamps taking in the form of light bulbs (e.g. A19, C9, BR30, PAR30 bulbs) or luminaires in linear, round, and rectangular configurations. The light sources used in multicolor LED systems can be individual LEDs that emit light with monochromatic colors, integrated three-, four- or five-chip LED packages, or a combination of integrated RGB LEDs and single-color LEDs.

Multicolor LED systems operate under the principles of additive color mixing. Additive color mixing refers to the mixing of three primary colors of visible light (red, green, and blue) to create secondary colors. The color-mixing gamut is defined by the light sources used in the system. The color capabilities of RGB lighting systems are adequate for a range of applications. However, RGB lights fail to generate beautifully deep colors all over the spectrum, vibrant fullness in tinted light, and high quality white light. The color capabilities of RGB lights can be augmented with the addition of other colored LEDs. The addition of amber LEDs allow an RGBA system to create a large gamut than that from red, green, and blue alone. The fourth channel expands the available range of colors to include warmer tones such as rich gold, yellow, and orange shades, enabling creation of dramatic and vibrant lighting effects. Adding a white LED to the RGB system does not expand the color-mixing gamut, but enables creation of saturated reds and a full range of pastels as well as high quality white light that can enhance the rendering of illuminated skin tones and colored objects. Incorporating both amber and white LEDs to create an RGBWA system allows unlimited color mixing to reproduce a spectrum of breathtaking color or vibrant white light.

To produce predictable colors from a color changing LED light, each of its LED channels requires individual, accurate dimming control. There are various ways to drive multi-emitter systems for color and brightness control. Accurate color and brightness control can be achieved with pulse-width modulated (PWM) dimming of the individual LED channels. An alternative to PWM dimming is constant current reduction (CCR) dimming which operates by adjusting the current flowing to the LEDs. The use of CCR dimming, however, requires an acceptable tolerance in the color temperature because a color shift can occur when the current to the LED is below the rated current. DMX512 is the most used of protocols for controlling multicolor LED systems for architectural, entertainment, stage and theatrical lighting applications. Remote Data Management (RDM) is an enhancement to the DMX protocol that allows two-way communication between controllers and RDM-enabled color changing lights.
 
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