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Staying in Tune with Your Lighting Requirements

May 17, 2017

The new Bridgelux Vesta™ Series of LED lighting components will be available for ordering this summer.  This new family is based on products for tunable white applications.  “Tunable white” is a pretty trendy topic in the lighting industry these days, and for most, its meaning is becoming clearer.  But, let’s spend a bit of time to define what we here at Bridgelux are talking about when we say “tunable white,” and what we think its important attributes are.

First, and simplest to define, are products for dim-to-warm applications. With the widespread adoption of LED lighting, consumers have been quick to notice that their new LED fixtures and lamps don’t behave as expected when dimmed.  LED sources generally remain at a constant correlated color temperature (CCT) at all intensity levels.  This is inconsistent with traditional lighting such as incandescent and halogen sources that produce warmer, lower CCT, light as they are dimmed.  For many consumers, this particular attribute of LEDs is no problem and may even be preferred.  But for some consumers, and more specifically for certain applications, the “old-fashioned” dimming behavior is missed.  For residential and hospitality applications, a candle-lit ambience is desired, and this has spurred several LED manufacturers to create products that mimic incandescent behavior.

The warm dimming effect has been achieved with varying degrees of success, and is most often achieved by using SMD packages emitting different CCTs.  This may work well for larger downlights, but chip on board (COB) sources are most desirable for smaller fixtures, like track and spot lights.  Similar to several other alternatives, the Bridgelux Vesta™ Series Dim to Warm Array will tune from 3000K down to 1800K.  This is easily accomplished using a standard, single-channel LED driver, which eliminates a great deal of system cost and complexity.  Unlike other solutions, Bridgelux solutions have CRI values >95 and R9 values >90, which are closer to incandescent values, and the CCT drops smoothly throughout the dimming curve.  Other solutions reach the minimum CCT at a fairly high dimming level, which can leave your space glowing bright orange.  This may be great for Halloween, but is not the ambience most are trying to achieve!

 

Typical characteristis of a Vesta™ Series Dim to Warm Array

The second type of tunable white products in the Vesta family allow the user to tune across a much wider range of CCTs and control dimming and CCT independently.  The upcoming Bridgelux products are the Vesta™ Series Tunable White Array, Vesta™ Series Tunable White Linear, and Vesta™ Series Tunable White Circular.  There is a lot of excitement in the industry about these types of products, and while all the research isn’t yet completed, there certainly is great potential to address personal preference, productivity in the workplace and schools, and even health concerns using these tunable white light sources.

Even within this type of tunable white product, one big variable is the number of channels.  Having a larger number of independent channels, each with its own CCT or monochromatic wavelength, allows for sources that can tune CCT precisely along the blackbody curve with very high color gamut and fidelity.  The tradeoff to this solution is the complexity of driving more than two channels, and ultimately the cost of such a system.  For many applications, however, this level of complexity is not necessary and not in the specifiers’ budget.  In these cases, a two-channel system can be used, which allows for linear tuning between the two endpoints in the LED source.  Tunable white Vesta products are based on this approach, but still designed with quality of light in mind.

For larger downlights and for linear applications we offer a series of products based on the Bridgelux SMD and EB families of products.  Here, optical requirements are more relaxed and there is greater need to maximize lumens per dollar.  Linear options will be available first, with circular options to follow.

For more demanding applications, our tunable white COB products are a great choice.  In this case, we have chosen another emerging technology, chip-scale package (CSP) emitters.  The use of CSPs allows us to maximize lumen density, color angular uniformity, and color spatial uniformity.  By mixing light from two different CCT emitters at the source level, the burden of using costly and inefficient optics is reduced.  These arrays are the perfect choice for narrow beam spot and track lights in high center-beam candlepower applications.  The Bridgelux Vesta™ Series Tunable White Arrays produce high quality light with a minimum CRI of 90, and allow CCT tuning from 2700K to 5000K – ideal for indoor retail and hospitality lighting applications.

Typical flux characteristics of a Vesta™ Series Tunable White Array

We are just now beginning to see more widespread use of tunable lighting – a unique way to take advantage of solid-state LED technology and make lighting more personal and human-centric.  This field will certainly be growing rapidly in the coming years.  Please be sure to follow Bridgelux on our website and social media accounts to learn about all our new, high quality products in this and other areas.