As the
light emitting diode (LED)
market continues to grow, pressure increases for lighting manufacturers
to stay ahead of the curve, especially with hundreds of new players
jumping in to take advantage of the $2 billion dollar potential.
Many have little experience with electronics, being more familiar
with standard florescent and incandescent bulbs. The literally million
dollar question for these companies becomes how to set their lighting
design apart from all the other competitors out there.
Currently, when most lighting customers think about differentiation,
they think about using color LEDs for mixing light. These RGB, RGBA,
etc. applications fit an interesting niche in both architectural and
stage lighting designs.
However, a lack of imagination has gripped the market in terms
of taking many of these same principles and attacking the substantially
larger White Light market.
Most engineers are currently creating "me-too" white light designs
by taking "x" number of white LEDs from a manufacturer such as Lumileds, adding up the lumens
to
equal or surpass that of a fluorescent, hooking it up to a ballast, and
calling it good. This does not appear to be a recipe for long-term
success.
There are few technological advances that stop at the replacement
level, and as customers gain a new perspective on the additional
features of LEDs, it would be unfortunate to assume that there would be
no further utilization.
This article will explore several examples of differentiating what
appears at face value to be a simple LED design. Each of these examples
deserves far more space than can be devoted to here, but should serve
as a starting point for additional creativity.
The key to this step is the addition of basic intelligence to the
circuit, generally in the form of a microcontroller. Intelligence is
necessary to take advantage of what LEDs offer as much to white light
designs as to color.
Tune to Temperature
The first example of a key differentiating feature is the ability to
tune color temperature along the black body locus. It is relatively
simple to imagine why one wants to mix color, and still there has yet
to be substantial progress made towards the same principles with white
light.
As lighting customers become more discerning, the option of any
specific color temperature between 3000K and 6500K is appealing. This
also means that designers can maintain a single white light fixture
design that avoids the need for constant revision dependent on a Correlated Color Temperature (CCT)
specification.
What is interesting to note about tuning white light is that it
actually is normally done through mixing color LEDs. This originally
was done with a simple RGB interface, but designers quickly noticed
that the Color
Rendering Index (CRI)
was extremely poor.
CRI is important in order to reproduce an item's color as it would
be under natural light, especially vital in such applications as
display lighting. A merchant doesn't want good jewelry looking bland.
To alleviate this concern, designers have tried RGBA, RGGB, and
RGBW, and each configuration has their advocates. Intelligence can
ensure that whatever LED configuration a designer selects will have the
best possible CRI by calculating the dimming percentages required to
drive the LEDs efficiently. Companies such as Future Electronics have
done excellent work in assisting designers with this often difficult
process.
Even if a high CRI is not a top design requirement, some sort of
simple tuning can be beneficial, this time only with two strings of
white LEDs, cool and warm white. This approach can provide the same
number of lumens while also allowing the designer an easy way to
differentiate the product, especially from standard fluorescent bulbs.