Understanding the many facets of tunable LED lighting

- Oct 07, 2018-

With the evolution and fast advancement of LED technology, manufacturers could provide advanced LED lighting solutions that were well-accepted by the consumers. Further advancement of LED technology also helped lighting designers and manufacturers to provide smart and connected lighting products.

Flexibility of tunable LED lighting

While cool, neutral and warm white LED lighting was preferred by the users, lighting designers and manufacturers introduced tunable LED-based products, which helped the designers todesign different tuning ranges, optimalintensity control, and improve light quality. Tunable LED lighting also could be tuned to a desired CCT at any time by the user. But LED lighting solutions can offer much more beyond just choosing options of CCT, as per the requirements of different applications.

It is possible to deliver tunable-white light sources that facilitate the smooth adjustment between the limits of extremely cool to extremely warm.

Further, natural human responses to phenomena like sunrise and sunset have conditioned people to anticipate tones to be cooler when lighting is brightest and to become warmer when it is dimmed. This is the reason why bar and restaurant owner often attract customers by presenting a cool and stimulating environment during daytime hours, while using lighting to generate a warm glow during the evening.

Another potential step for tunable-white LEDs is to bring in control over color saturation.This is called Du´v´ tuning, which requires three control handles for CCT, intensity, and
Potential of tuneable LED lighting

After using varying LED lighting solutions, consumers are now ready for tunable white LEDs, thus paving the way for lighting specifiers, architects, interior designers and facility managers to employ their knowledge of the effects of varied white shades of LED lighting to influence behaviour and moods of people.

Each tunable-white shade consists of a predefined path. With three or more colors, it can track the BBL and dim the intensity of the resulting white light.

Alternatively, two-color sources follow a straight line over a restricted tuning range. Hence, the resulting flux has limitations because of the averaging effect of cool white and warm white required to strike the right CCT.

How tunable LEDs are different from white LEDs

White LEDs are made either by mixing light from several red, green, and blue (RGB) monochromatic emitters or by fabricating phosphor conversion of blue. A blend of these two methods was also sometimes used.

Tuneable white LED source is characterized by the number of colors or whites used to attain the final CCT. There are about seven color sources that can be mixed for tunable-white developments.

In some tunable-white light sources with three or more colors, these white CCTs lie along the daylight locus (DL) and black body locus (BBL) that cross the long-established CIE (International Commission on Illumination) color space and those sources offer a higher-quality white as defined by CRI, the R9 CRI red sample, and the relatively new TM-30 color-fidelity metric published in 2015 by the Illuminating Engineering Society of America (IES).

Control requirements for tuneable LED lighting

After the development of tunable LED lighting it was time to develop an interface for the users to adjust the lighting as per their requirements. A color-aware user interface was essential to facilitate the user to set CCT and flux levels directly. Wireless connectivity was finally chosen as the interface to control tunable-white lighting.

Bluetooth Low Energy (BLE) mesh networking holds huge advantages for tunable LED lighting such as end-to-end solution. Further, lights can also be controlled by smartphone apps.

Secure networks with four levels of access can be installed to control multiple light nodes that expand over large distances without gateways, and can be controlled from a single terminal with negligible limitation on communication range.

Since all devices on a BLE network can promote their presence, the controlling app can be authorized to access all lighting fixtures. This feature can help to commission and manage a network of tunable light fixtures in any commercial environment.

The tuneable white LED market is young for manufacturers to back one wireless option over another. One useful way to give luminaire developers the flexibility to have multiple connectivity choices is a modular design. A flexible scenario can be realized by having a basic 0-10V driver that works with varied modular control boards. This facilitates tunable-white solution to be collected and commissioned with minimum effort by plugging the selected control module into headers on the fundamental driver board.

Future of dynamic lighting
Lighting designers and makers and even end users are now familiar with the effects that can be obtained by dynamic white lighting. Tunable-white LEDs have the potential to support even more varied effects. Further, control options for tunable white LEDs can be simplified with developments like mesh, and intuitive controls. Such developments are important in enabling this stimulating technology to deliver its maximum potential.