May 16, 2017: Tunable-white LED lighting has been the latest trend in commercial lighting. A simple yet attractive way to make a workplace look more attractive is to redesign the office environment with tunable-white LED lighting. Besides offices, tunable-white LED lighting is also becoming increasingly popular in healthcare and education applications.
Lighting plays a vital role in affecting our mood, perception, and psychological wellbeing. By imitating natural daylight, Tunable-white LED lighting, is therefore, designed to do away with the strains and discomfort that traditional lighting leaves on us.
Tunable-white LED lighting uses a combination of controllable channels to adjust the colour temperature of the luminaire. The channels in a tunable-whites produce white light with varying colour temperatures. The colour spectrum of these lights range from cooler and bluer tones, to warmer amber tone. These luminaires can produce both warm and cool tones to imitate the the circadian rhythm.
The morning light allows our bodies to produce cortisol which helps the body to awake. In the evening, the light mimics the light and temperature of sunset, which helps our bodies to produce melatonin, which helps us to sleep.
The basic systems
The basic tunable linear systems use LED strips placed side-by-side. One channel will be 2700K in colour temperature, and the other about 6000K. The LED strips are placed inside an aluminium extrusion fitted with an opal diffuser, which mixes the colour as the light passes through it. This however is a very basic system.
With advancements, most tunable-while LED systems use multi-chips where a number of LED chips are placed in the same module. Here colour mixing takes place as the light leaves the module. These multi-chips have a much higher performance compared to individual LED strips.
Tunable whites are not exempted from the color rendering issue. Although manufacturers claim Good colour performance in all ranges of tunable-whites, but in reality, there is no certainty that the mixed light would perform well. Actually, the greater the number of channels, the better colours will look under them.
While some tunable-white systems offer a wide natural ‘circadian rhythm’ range that changes from candlelight to daylight, there are other systems with smaller range—from 2500K to 4000K, which can be used as a decorative light.
While the basic systems use manual control to alter white outputs, other are designed to replicate the effect of dimming on a filament source. As the light is dimmed, the lamp warms up. This is again a manual control method.
The more sophisticated control systems are designed to replicate the circadian rhythm of the room occupants. Here, the lighting settings are programmed into the control architecture. In this system, colour temperature and light level can be pre-set.