LED Explained

History

After fire, incandescent light, and fluorescent light, LED technology is only the fourth major innovation in our history of creating artificial light.  As the world’s first solid-state light source, LED lights mark a dramatic advancement in the way light is created, and in how we generate light from electric current.

Function

LEDs have been a part of our lives for over forty years.  First used as indicator lights in remote controls for televisions and other electronic devices, LEDs are also used in remote controls that operate on infrared frequencies.  The use of LEDs as light sources in mainstream society, however, is a relatively recent development.  Falling production costs, dramatically improved light quality and luminous efficiency, and greatly increased lifespans have propelled LED lights into the mainstream.

At their cores, LED lights are electronic devices.  Instead of heating a filament or energizing a gas, LED bulbs create light by passing current through a semiconductor material.  The current excites electrons in this material causing them to emit small packages (photons) of light.  It is these photons of light that we see.  By using different kinds of semiconductor materials, we can vary the light’s colour.  Common semiconductor materials include AlInGaP (aluminum indium gallium phosphide) and InGaN (indium gallium nitride).

As with any electronics device, LED lights require a steady current and reliable means of dissipating heat.  The light’s driver is responsible for regulating current flow to the diode.  The driver is essential to the LED’s function, and its failure can damage or destroy the LED.  Driver technology has advanced considerably in recent years, and LPI’s LED lamps and luminaires now boast useful lives ranging from 50 000 to more than 100 000 hours, thanks largely to the quality of their drivers.

Dissipating the considerable heat the diode generates is also essential.  LED light manufacturers have created a number of strategies to dissipate heat, including heat sinks and miniature fans.  Though cheaper, fan units are prone to premature failure.  Since they cannot be replaced, a failed fan means a premature lamp replacement.  In contrast, a properly designed heat sink cannot fail – there are no moving parts, and the sink itself is not affected by the light’s operation.  However, not all heat sinks are created equal – sinks made of highly conductive materials such as nickel and aluminum and having large surface areas are superior.  This is one of several reasons why LPI proudly offers a range of LED lamps from Aeon Lighting Technology (ALT).  ALT’s patented fin-shaped heat sink technology gives its lamps their distinctive appearance.  ALT’s lamps have twice won the coveted reddot design award – a fitting tribute to their products’ superior construction.

Applications

LED lighting technology is now sufficiently mature and reliable to offer replace conventional lighting in a number of settings.  For example, LED lamps are as much as 75-percent cheaper to operate than their incandescent and halogen equivalents.  And realizing these savings is often as easy as unscrewing the existing incandescent/halogen lamp and replacing it with an LED equivalent.  Whether they light an elite jewelry boutique, a restaurant, a lobby, or a home, incandescent and halogen lamps waste electricity and create needless expense.  LED lamps are a clearly superior alternative.  In fact, the savings are so dramatic that LPI established its Lamp Retrofit Program specifically to assist conventional lamp users upgrade to LED.

Lamps aside, LED lights are also viable alternatives elsewhere.  In parking garages, for example, LED parking luminaires offer substantial total cost of light savings when compared to metal halide and high pressure sodium luminaires.  As in other applications, LED’s lower cost derives from a longer service life and much lower rate of power consumption.  LEDs are also replacing linear fluorescent fixtures in a number of applications, including cove lighting and ceiling light panels.

LED lighting owes much of its broadening adoption to three technical factors:  increasing light quality, a wider array of colour temperatures, and increasing light output.  Lighting engineers often refer to a light’s colour rendering index (CRI) when describing its quality.  The CRI is a numerical scale derived from a light source’s ability to reproduce accurately a set range of colours relative to a reference light source, usually the sun.  A higher CRI means the light source renders light more accurately.  Many LED light sources now have CRIs of 80, a level more than adequate for everyday background lighting.  When very accurate colour representation is necessary, LPI advises using products with CRIs of 90 or more.

A light’s temperature is often expressed in terms of its warmth using the correlated colour temperature (CCT) scale.  The CCT is based on the principle that as an object is heated, the colour of the light it gives off changes.  A piece of metal glows red, then white, and then blue as its temperature rises.  These changes occur at characteristic temperatures, which we measure in Kelvin (K).  Older LED lights were sometimes criticized for appearing too cold because of their bluish tinge and (paradoxically) high CCTs in the 6000-6500K range. Improvements in component technology have lowered LED CCTs into ranges called warm white (~2540K), natural white (~3500K), and true white (~4500K).  As a result, LED light sources can now simulate the yellowish colour of traditional halogen bulbs, while also offering the whiter colours characteristic of light sources in business and commercial settings.

LEDs used in indicator lights are called low output LEDs.  They general produce a fraction of a lumen of output (a lumen is a unit of measurement describing how much light a light source produces).  A standard fluorescent tube, by comparison, produces about 700 lumens per foot (2800 lumens per four-foot tube).  Only in the past ten years have LEDs produced enough light to be used in everyday lighting.  And only in the past five years have these lights declined in price sufficiently for mainstream use.  Even so, LEDs have yet to be widely embraced as conventional lighting replacements.  Relatively high purchase prices and difficulties in comparing and LED’s light output to a conventional light’s are two reasons why.  As comparisons between LED and conventional lights shift from initial cost and light output to total cost of light and delivered light, respectively, LED’s superior performance will become clearer and its pace of adoption will accelerate.

Benefits

LED light sources offer many advantages over traditional light sources.  Here are the main ones:

  1. Very low power consumption.  LED light sources consume up to 85 percent less power than conventional light sources.  This means LED lights can save you as much as 85 percent of your current lighting-related hydro costs.
  2. Very long lifespans.  LED light sources generally last between 50000 and 100000 hours, far longer than conventional lights.  As a result, you no longer need to waste time or money replacing lights every few months or years.
  3. UV light-free.  LEDs produce light in specific parts of the visible spectrum.   As a result, they produce no UV light.  This is particularly important for art galleries, since UV light can damage print media.  Lowering human exposure to UV light has numerous health benefits, too, including reducing the risk of skin cancer.
  4. Mercury-free.  In contrast to CFL and fluorescent tubes, LED lights contain no mercury, making them an environmentally responsible light choice.
  5. Incentive-eligible.  Hydro companies want you to conserve energy, and many offer incentive programs to offset the cost of upgrading to LED.
  6. Lower total cost of light.  Though more expensive to buy, LED lights more than make up for their purchase price with savings in power consumption, lamp replacement costs, and maintenance costs.  In many cases, LEDs pay for themselves in a matter of months, leaving you with many years to enjoy dramatic savings.  For comparisons between specific conventional lamps and their LED replacements, read about our retrofit programs.

We hope this page has helped inform you about LED lighting’s technology, uses, and many advantages over conventional lighting.  For more information, have a look at our frequently asked questions, or contact us.