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E L E CT R I C AL CONNE CT I ON
AUTUMN 2 01 5
GUIDING LIGHT
The International Year of Light
T
he United Nations has proclaimed
2015 as the International Year
of Light (IYL), recognising the
importance of the role light plays in
everybody’s lives.
An entire year dedicated to light, you
ask? Well, thanks to light’s properties as
both a tangible technology and element,
it is perhaps the number one cross-cutting
discipline of science in the 21st century
(remember that without light running
across cables, there would be no internet).
The timing of last year’s Nobel Prize in
Physics could not have provided a better
segue into the IYL.
The 2014 prize was awarded to the
creators of the blue light emitting diode
(LED). This discovery enabled not only a
multitude of modern devices from sensory
lighting to mobile phones, but also a new
generation of bright, energy-efficient bulbs,
with the Nobel committee recognising the
transition from incandescent bulbs lighting
up the 20th century, to present LED lamps.
LIGHTING UP THE 21ST CENTURY
The lighting industry is undergoing a
radical transformation that has opened up
exciting and ground-breaking possibilities,
and it is all thanks to LED.
LED technology has come a long way
since being introduced decades ago as
mere indicators for gadgets. Today, LED
lighting has been rapidly gaining traction as
a sustainable, highly efficient way to light up
homes and buildings, to stadiums and cities.
But what is it about LED technology that
has driven the switch from incandescent
bulbs to LEDs? The long list of advantages
associated with LED lighting systems
has led to the significant and sustained
increase in their use around the world.
Key factors that have heightened the
use of LED in both indoor and outdoor
applications include energy efficiency,
absence of mercury, long lifetimes in
residential and commercial use, no
emitted infrared or ultraviolet radiation
and durability.
UNDERSTANDING LED
In the IYL, education is a key pillar across
every aspect of light and light-based
technologies for the global initiative. When
you start exploring LED technologies you
very quickly find there are a few basic
terms and concepts that it is worth getting
familiar with or re-familiarising yourself
with. These include:
>
LED:
An LED is a semi-conductor
device or chip that produces light
when an electrical current is applied.
What’s important to remember is that
LEDs are just one of many components
– optics, housing, power sources,
to name a few – used to create an
LED fixture or lamp. When looking at
claims about lifetime, efficiency, and
design, it is essential to compare the
specifications of the entire LED system
as a whole, not just the specifications
of the individual system components.
>
Efficiency and efficacy:
The ‘efficacy’
of a lighting fixture is usually expressed
as the amount of light (in lumens)
produced by a certain amount of
electricity (in Watts). Lighting fixture
‘efficiency’ is the ratio of the total lumens
exiting the fixture to the total lumens
produced by the light source.
It is important to note that the efficacy
of the LEDs themselves is always greater
than the efficacy of the LED fixture. This
is caused by many factors including
losses as light bounces off reflectors and
passes through lenses. Make sure when
2015 is the International Year of Light and light-based
technologies, explains
Steve Arthur
, and education is key.