LEDs: The Light of the Future

Light Emitting Diodes (LEDs), “semiconductorstraditional bulbs.[11]
that emit light when zapped with [positive polarity]LEDs also produce no ultra-violet output, which can
electricity,”[1] are on the verge of taking over thedamage fabrics, unlike traditional bulbs; they are
commercial and consumer sectors of the lightinglight-weight, ecologically friendly, and can produce
industry. With greater efficiency, longer useful lives, anddifferent colors (without the use of color filters) based
their “clean” nature, LEDs are the future ofon the amount of power provided to each primary
light, pushing traditional incandescent and flourescentcolor ensuring that electricity is not wasted. The
bulbs toward extinction. Only the higher productionMassachusetts Institute of Technology (Nano
costs for LEDs has extended the existence ofStructures Lab) is presently conducting research that
traditional bulbs.could lead to the creation of an LED “where
Historyboth color and intensity (brightness) can be set
When viewing the history of traditional bulbs, the higherelectronically.”[12]
costs associated with producing LEDs is not anUses and the Future
insurmountable hurdle to overcome. The incandescentAs LEDs gain a greater portion of the lighting market,
bulb lingered for about 70 years before supplantingthey are currently used in a variety of devices and
“candles, oil lanterns, and gas lamps” as theapplications ranging from traffic control devices (e.g.
main source of lighting.[2] When the first crudetraffic lights, which include the single signal device that
incandescent bulb was created in 1809 by Humphreychanges colors from green to yellow to red), barricade
Davy, an English chemist, using two charcoal strips tolights, hazard signs, message displays (e.g. Times
produce light, it remained impractical. Later when theSquare, New York, commodities and news message
first true incandescent bulb was created by Warrenboards, scoreboards), cellphones, televisions, large
De la Rue in 1820, utilizing a platinum filament tovideo screens used at sporting and other outdoor
produce light, it was too expensive for commercial use.events (e.g. Miami Dolphins end-zone screen),
Only when Thomas Edison created an incandescentcalculators, digital clocks and watches, flashlights
bulb utilizing a carbonized filament within a vacuum in(including models for which 60 seconds of manual
1879, did the incandescent bulb become practical andwinding provides one-hour of light, eliminating the need
affordable for consumer use.to stockpile fresh batteries for emergencies),
Although considered relatively novel, the concept forChristmas lights, airport runway lights, buoy lights, and
LEDs first arose in 1907 when Henry Joseph Roundautomotive applications (e.g. indicator lights as well as
used a piece of Silicone Carbide (SiC) to emit a dim,head lights and signal lights in some vehicles;
yellow light. This was followed by experimentsdriver’s of the new 2006 Ford Mustang can
conducted by Bernhard Gudden and Robert Wichardeven change the color (125 different varieties) of their
Pohl in Germany during the late 1920s, in which they“LED-laden dashboard by using the
used “phosphor materials made from Zinc‘MyColor’ feature”[13]).
Sulphide (ZnS) [treated] with Copper (Cu)” toIn fact the automotive industry plans to replace all bulbs
produce dim light.[3] However, during this time, a majorwith LEDs by 2010, while efforts are currently
obstacle existed, in that many of these early LEDsunderway to replace all traffic signals with LED
could not function efficiently at room temperature.devices. At the same time, plans are in place to
Instead, they needed to be submerged in liquid nitrogeneventually use LEDs to light streets as well as much of
(N) for optimal performance.the Third World and other areas “with no means
This led to British and American experiments in theof electricity” since “solar charged
1950s that used Gallium Arsenide (GaAs) as abatteries” can power LEDs for the duration of
substitute for Zinc Sulphide (ZnS) and the creation ofeach night. [14]
an LED that produced invisible, infrared light at roomIn addition, “Phillips Electronics is developing
temperature. These LEDs immediately found use inremote-controlled LED room lighting [while] Boeing
photoelectric, sensing applications. The firstCorp. plans to use LED’s throughout the interior
“visible spectrum” LED, producingof its new 787 Dreamliner commercial jet.”[15]
“red” light was created in 1962 by NickWith the promise that LEDs hold, it is likely that
Holonyak, Jr. (b. 1928) of the General Electric Companysomeday they will provide illumination for houses and
who used Gallium Arsenide Phosphide (GaAsP) inoffices, X-Ray capabilities for the medical field, power
place of Gallium Arsenide (GaAs). Once in existence,computer monitors, as well as an assortment of other
they were quickly adopted for use as indicator lights.devices and applications. The possibilities are endless.
Before long these red LEDs were producing brighterHowever, before LEDs can supplant the traditional bulb,
light and even orange-colored electroluminescence“designers and advocates of the technology
when Gallium Phosphide (GaP) substrates were used.must overcome… the usual obstacles to
By the mid 1970s, Gallium Phoshide (GaP) itself alongmainstream market adoption: Industry-accepted
with dual Gallium Phosphide (GaP) substrates werestandards must be developed and costs must be
being used to produce red, green, and yellow light. Thisreduced.”[16] Currently costs are coming down
ushered in the trend “towards [LED use in] moreand some companies are moving towards these
practical applications” such as calculators, digitalindustry standards (e.g. Phillips Electronics is working on
watches and test equipment, since these expandedLED bulbs that can screw into existing light sockets,
colors addressed the fact that “the human eyewhile already offers LED screwable bulbs -- one
is most responsive to yellow-green light.”[4]consisting of 70 LEDS that emits a "warm white color
However, rapid growth in the LED industry did notsimilar to the light from an incandescent bulb"[17] using
begin until the 1980s when Gallium Aluminium Arsenidesonly 3 Watts of energy and another LED bulb that
(GaAIAs) were developed, providingactually changes colors when lit). With these efforts
“superbright” LEDs (10x brighter than LEDsalong with the adoption, exploitation, and production of
in use at the time) – “first in red, then yellowLED technology by growing numbers of companies, it
and… green,” which also required lessis inevitable that LEDs will become the sole source of
voltage providing energy savings. [5] This led to thelighting rendering traditional incandescent and
concept of the first LED flashlight, in 1984.fluorescent bulbs extinct. In short, LEDs are the light of
Then in parallel with emerging laser diode technology,the future, a light that will benefit not only consumers
which focused on maximizing light output, the firstbut also industry and the Earth in general.
“ultrabright” LEDs were created in the early__
1990s through the use of Indium Gallium Aluminium[1]Evan Ramstad and Kathryn Kranshold. Changing the
Phosphide (InGaAIP) led in part by Toshiba’sLight Bulb. The Wall Street Journal. June 8, 2006. B1.
creation of an LED that “reflected 90% or more[2]The History of the Light Bulb. 9 June 2006.
of the generated light…” In addition, during[3]A brief history of the Light Emitting Diode (LED).
this same period, it was discovered that differentWavicle Ltd. 2002-2006. 9 June 2006.
colors, including “white” (although a[4]The History of LED Technology. Marktech
“true” white light was only recentlyOptoelectronics. 2006. 8 June 2006. [
produced through the use of an organic LED (OLED)[5]A brief history of the Light Emitting Diode (LED).
by Cambridge Display Technology, in the U.K.) could beWavicle Ltd. 2002-2006. 9 June 2006.
produced through “adjustments in the size of the[6]The History of LED Technology. Marktech
energy band gap” when Indium Gallium AluminiumOptoelectronics. 2006. 8 June 2006. [
Phosphide (InGaAIP) was used, much in part because[7]A brief history of the Light Emitting Diode (LED).
of the work of Shuji Nakamura of Nichia Corporation,Wavicle Ltd. 2002-2006. 9 June 2006.
who developed the world’s first blue LED in[8] Joab Jackson. Accidental Find to Signal
1993.[6] Today, this technology is used to produce“Lights Out” for Incandescent Bulbs?
LEDs that even emit “exotic colors” suchNational 1 November 2005. 9 June 2006.
as pink, purple and aqua as well as “genuine[9]Joab Jackson. Accidental Find to Signal “Lights
ultra-violet ‘black’ light.[7]Out” for Incandescent Bulbs? National 1
A critical milestone was reached in 1997 when itNovember 2005. 9 June 2006.
became cost effective to produce “high[10]Joab Jackson. Accidental Find to Signal
brightness” LEDs in which the intensity (benefits)“Lights Out” for Incandescent Bulbs?
exceeded the associated costs to produce it.National 1 November 2005. 9 June 2006.
In conjunction with this milestone, newer technology is[11]Light-emitting diode. 2006. 9 June 2006.
emerging that will likely reduce costs even further (and[12]A brief history of LED lighting. 9 June 2006. [
improve lighting) – the introduction of quantum[13]Evan Ramstad and Kathryn Kranshold. Changing
dots or microscopic crystals ([8]the Light Bulb. The Wall Street Journal. June 8, 2006.
AdvantagesB6.
The advantages of adopting LEDs to provide sole[14]A brief history of the Light Emitting Diode (LED).
source lighting for every application are significant.Wavicle Ltd. 2002-2006. 9 June 2006.
LEDs emit virtually no heat (wasted energy) and are[15]Evan Ramstad and Kathryn Kranshold. Changing
“in fact… cool to the touch” unlikethe Light Bulb. The Wall Street Journal. June 8, 2006.
incandescent light bulbs. They are also more durableB6.
(encased in a hardened shell and resistant to vibration[16]Joe Knisley. Understanding LED Technology.
and shocks) than and last up to 50 times longer thanEC&M. 1 April 2002. 8 June 2006.
traditional incandescent and fluorescent bulbs ( some[17]70-LED Light Bulb, White Large Globe. 10 June
can be used for up to 10 years), and they “use a2006. [
greater proportion of the electricity flowing through___________________________________
them” translating into “savings forSources:
consumers.” [9] According to the U.S.A brief history of LED lighting. 9 June 2006. [
Department of Energy, “widespread adoption ofs&ct=clnk&cd=3
LEDs could cut U.S. consumption of electricity forA brief history of the Light Emitting Diode (LED).
lighting by 29%”[10] since they require lessWavicle Ltd. 2002-2006. 9 June 2006.
energy to function and by their nature, reduce theCameron Walker. Green Christmas: Tips for an
amount of air conditioning needed to keep areas coolEco-Friendly Holiday.Changing the Light Bulb. The Wall
and comfortable.Street Journal. June 8, 2006.
The shape of LEDs also provides lighting benefitsJoab Jackson. Accidental Find to Signal “Lights
when compared to that of traditional bulbs. UnlikeOut” for Incandescent Bulbs? National 1
incandescent and fluorescent bulbs, LEDs do notNovember 2005. 9 June 2006.
require the use of an external reflector to collect andJoe Knisley. Understanding LED Technology.
direct their light. In addition, “LEDs light up veryEC&M. 1 April 2002. 8 June 2006.
quickly… achiev[ing] full brightness in approximatelyLED Light Bulbs. 10 June 2006.
0.01 seconds – 10 times faster than”Light-emitting diode. 2006. 9 June 2006.