Signs of the Times - June 2015 - 36

LED Update
By M. Nisa Khan, Ph.D.

LED's Next Step
High-quality LED signage, display and lighting
improvements remain distant.

LED display buyers should exercise
caution when acquiring low-price
devices, because they typically
lack high-quality LEDs and sophisticated electronic-control systems.

nquestionably, modern LED
lamps offer unique benefits in many
signage applications, but they still
face quality, cost and dependability
challenges, despite the increasingly
impressive LED-based display,
signage and lighting technology
developments and any accompanying
marketing efforts. Today, interestingly, many early naysayers have
switched to LED lamps for both
replacement and new-installation
applications. Further, the technology
has provided new business opportunities for distributors and retailers
and, in turn, many of us have
become LED-product consumers.
Also, in addition to signage, lighting

and displays, the LED industry
is making remarkable inroads in
numerous other application areas.
Health, agriculture, and security,
are such examples.
Writer Heather Clancy, in her
December, 2013 Forbes magazine
article, "Why LED Retrofits Are
The Trojan Horse of The Internet
of Things," predicted LED lighting
integrating into Internet-of-Things
(IoT) systems as an outlier revenue source. Her primary themes
comprised:
* Reduced LED prices and increased
LED use;
* Expansion of lighting-control
systems;
* LEDs' inherently controllable
nature and easy integration into
light-management systems; and
* LED luminaires' use as carriers
for such "smart" sensor systems
as environmental-, surveillanceand promotional-lighting sensors.

Figure 1: The diverging rays, orthogonal to the sun's surface, illustrate the
Divergence Theorem in nature.
36 SIGNS OF THE TIMES June 2015

Dr. M. Nisa Khan
is president of IEM LED
Lighting Technologies.
She consults in the solidstate lighting industry
and educates consumers
about LED lighting. She
has a bachelor's degree
in physics and mathematics, and master's and
Ph.D. degrees in electrical
engineering. Email her at
nisa.khan@iem-led.com
Clancy referenced a parking-lot
owner who decreased power bills
and simultaneously increased
security by installing a surveillance
system integrated with the LED
lighting.
Although integrating such technologies may succeed, we still face
LED lamps' general illumination
quality, which hasn't been addressed
properly. Nor have desirable solutions been realized.
LED lighting shortcomings
Because lighting and illumination
are both subjective, the practice
of wrapping "bells and whistles"
around off-the-shelf LED lamp
applications has been an effective
sales method. For example, novelty
light systems that provide different
color temperatures from the same
LED lamp appear more intriguing
to shoppers than enjoying glarefree, omnidirectionally uniform
light distribution, such as that
provided by standard, Edison-type,
incandescent bulbs.
Light directionality is advantageous for LED-lamped, signage-type
displays, both for backlighting
screen systems and in the facings
of electronic message centers.
Unfortunately, both display types
can become glaring if the lamp intensity is brighter than a humancomfort level; they can also appear
uncomfortably bright against a
dark background.
Simply applying color tuning
or dimming adjustments to LED
displays can optimize any ambientlight conditions. However, the preferred systems feature high-quality
LEDs, those which feature highluminous efficacy, brightness and a
long-life span. Such systems can be
dimmed to span broad luminance

Signs of the Times - June 2015

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