Question & Answer Forum

The light-emitting diode (LED) is a new light source that differs in important ways from existing light sources. This Q/A will help you familiarize yourself with the most common terms and try to answer some questions about LEDs. If you need to learn more about the technology, write us a question (info@liteld.com). We will be more than glad to help!

Q: What does SSL stand for?
Q: What does LED stand for?
Q: What makes LEDs different from other light source
Q: How long do LEDs last?
Q:
Do LEDs provide high quality lighting?
Q: What are the common types and packages of LEDs?
Q: What LED manufacturers does LiteLD use for its products?
Q: What features should you look for in evaluating LED lighting manufacturer?
Q: Why opt for LED lighting as light source?

 

Q: What does SSL stand for?

A: Solid-state lighting (SSL) technology uses semi-conducting materials to convert electricity into light. SSL is an umbrella term encompassing both light-emitting diodes (LEDs) and organic light emitting diodes (OLEDs).

Q: What does LED stand for?

A: Light-emitting diodes (LEDs) are based on inorganic (non-carbon based) materials. An LED is a semi-conducting device that produces light when an electrical current flows through it. LEDs were first developed in the 1960s but were used only in indicator applications until recently.

Q: What makes LEDs different from other light sources?

A:What makes LEDs different from other light sources? LEDs are semiconductor devices, while incandescent, fluorescent, and high-intensity discharge (HID) lamps are all based on glass enclosures containing a filament or electrodes, with
fill gases and coatings of various types.
LED lighting starts with a tiny chip (most commonly about 1 mm squared) comprising layers of semi-conducting material. LED packages may contain just one chip or multiple chips, mounted on heat-conducting material and usually enclosed in a lens or encapsulant. The resulting device, typically around 7 to 9 mm on a side, can produce 30 to 150 lumens each, and can be used separately or in arrays. LED devices are mounted on a circuit board and attached to a lighting fixture, architectural structure, or even a “light bulb” package.

Q: How long do LEDs last?

A: Unlike other light sources, LEDs usually don’t “burn out”; instead they get progressively dimmer over time. LED useful life is based on the number of operating hours until the LED is emitting 70% of its initial light output. Good quality white LEDs in well-designed fixtures are expected to have a useful life of approximately 50,000 hours. LiteLD products last over 75,000 hours.

A typical incandescent lamp lasts about 1,000 hours; a comparable CFL lasts 8,000 to 10,000 hours.

Q: Do LEDs provide high quality lighting?

A: Until recently, almost all white LEDs had very high correlated color temperature (CCTs), often above 5000 Kelvin. High CCT light sources appear “cool” or blueish-white. Neutral and warm white LEDs are now available. For most interior lighting applications, warm white (2700K to 3000K), and in some cases neutral white (3500K to 4000K) light is also appropriate.

Q: What are the common types and packages of LEDs?

A: Low power LEDs commonly come in 5 mm size, although they are also available in 3 mm and 8 mm sizes. These are fractional wattage devices, typically 0.1 watt, operate at low current (~20 milliamps) and low voltage (3.2 volts DC), and produce a small amount of light, perhaps 2 to 4 lumens.
High power LEDs come in 1-3 watt packages. They are driven at much higher current, typically 350, 700, or 1000 mA.

Q: What type of LED manufacturers does LiteLD use for its products?
LiteLD uses Nichia LEDs, a japan-based LED manufacturer. The choice was carefully studied and selected after thourough analysis in our R&D labs. Also the choice was made by what best suits our product designs and applications. Nichia LEDs are recognized and partners on R&D projects with the Department of Energy (DOE).

Q: What features should you look for in evaluating LED lighting manufacturer? (Checklist provided by the DOE)

  • Does the LED manufacturer publish thermal design guidance?
  • Does the lamp design have any special features for heat sinking/thermal management?
  • Does the fixture manufacturer have test data supporting life claims?
  • What life rating methodology was used?
  • What warranty is offered by the manufacturer?  

Why opt for LED lighting as light source?

  • Lighting the Way to Energy Savings

Solid-state lighting is a pivotal emerging technology that promises to fundamentally alter and improve lighting systems – and buildings – of the future. No other lighting technology offers so much potential to conserve electricity.

  • Long Life

LEDs life expentacies range between 30,000 - 75,000+ hours. If the product is left on 24-hours a day, 7 days a week, ann LED product can last approxiamtely 9 years without replacement, dimming, or increased energy consumption. LiteLD products are carefully designed to not electrically overdrive the LED products, unlocking the maximum lifespan.

  • Color quality of white LEDs

Three (3) distinct hues of white light exist: Warm, Neutral, and Cool white LED Light. Each operate at a different temperature. If the LED product is well designed, the light will be homogeneous. If the LED product was not well designed there may be uneveness in the light. This is often the case where different grades of LEDs are used to make up the product. In some cases, dark spots between the LEDs can be seen because the product was poorly designed.

  • Size advantage – can be very compact and low-profile.

The small size and directional light emission of LEDs offer the potential for innovative, low-profile, compact lighting design.

  • Directional light emission – directing light where it is needed.

Traditional light sources emit light in all directions. For many applications, this results in some portion of the light generated by the lamp being wasted. Special optics and reflectors can be used to make directional light sources, but they cause light losses. Because LEDs are mounted on a flat surface, they emit light emispherically, rather than spherically. This reduces wasted light.

  • Breakage resistance

LEDs are largely impervious to vibration because they do not have filaments or glass enclosures. Standard incandescent and discharge lamps may be affected by vibration when operated in vehicular and industrial applications, and specialized vibration-resistant lamps are needed in applications with excessive vibration. LED’s inherent vibration resistance may be beneficial in applications such as transportation (planes, trains, automobiles), lighting on and near industrial equipment, elevators and escalators, and ceiling fan light kits.

  • Cold temperature operation – performance improves in the cold

Cold temperatures present a challenge for fluorescent lamps. In contrast, LED performance inherently increases as operating temperatures drop. This makes LEDs a natural fit for grocery store refrigerated and freezer cases, cold storage facilities, and outdoor applications. In fact, DOE testing of an LED refrigerated case light measured 5% higher efficacy at -5°C, compared to operation at 25°C.

  • Instant on – require no “warm up” time

Fluorescent lamps, especially those containing amalgam, do not provide full brightness immediately upon being turned on. HID lamps also have a “re-strike” time delay; if turned off they must be allowed to cool down before turning on again, usually for 10-20 minutes. Newer pulse-start HID ballasts provide faster restrike times of 2-8 minutes. LEDs, in contrast, come on at full brightness almost instantly, with no re-strike delay. In general illumination applications, instant on can be desirable for safety and convenience.

  • No IR or UV emissions - LEDs intended for lighting do not emit infrared or ultraviolet radiation

Incandescent lamps convert most of the power they draw into infrared (IR) or radiated heat; less than 10% of the power they use is actually converted to visible light. Fluorescent lamps convert a higher proportion of power into visible light, around 20%. HID lamps can emit significant ultraviolet radiation (UV), requiring special shielding and diffusing to avoid occupant exposure. LEDs emit virtually no IR or UV. Excessive heat (IR) from lighting presents a burn hazard to people and materials. UV is extremely damaging to artwork, artifacts, and fabrics, and can cause skin and eye burns in people exposed to unshielded sources.

  • Environmetally friendly (Green Technology)

Until recently, the lighting industry has provided the world a no-win option where we either choose highly inefficient incandescents or follow the advice of media and government offices to use fluorescents that contain mercury, look horrible in most cases, and are typically not or only partially dimmable. These options do not lend well to the “build a greener future” philosophy of our great nation’s leaders. Fortunately, you no longer have to consider only these outdated technologies. Recent LED technological breakthroughs have signaled an entirely new battle on the lighting front. We now have sensible alternatives that last longer than both Incandescent lighting, and Compact Fluorescent (CFL) and give off a much more beautiful light. LEDs are not only mercury free, they're also 300% more energy efficient than fluorescent lights and about 1000% more efficient than incandescent lights.

Did you know that Fluorescent lights are filled with a gas containing low-pressure mercury vapor and argon, or sometimes even krypton? The inner surface of the bulb is coated with a fluorescent coating made of varying blends of metallic and rare earth phosphor salts., Our Gov’t is in a typical knee jerk mode in telling the world to move quickly into CFL. Sure, the energy savings would be huge, and possibly almost worth the trouble caused by the mercury disposal, however – why, when there’s a much more sensible option? The problem exists because each year, an estimated 600 million fluorescent lamps are disposed of in U.S. landfills, amounting to 30,000 pounds of mercury waste. Astonishingly, that's almost half the amount of mercury emitted into the atmosphere by coal-fired power plants each year. It only takes 4mg of mercury to contaminate up to 7,000 gallons of freshwater, meaning that the 30,000 pounds of mercury thrown away in compact fluorescent light bulbs each year is enough to pollute nearly every lake, pond, river and stream in North America (not to mention the oceans). In America, 1 in 6 children born every year have been exposed to mercury levels so high that they are potentially at risk for learning disabilities, motor skill impairment and short-term memory loss. Fortunately, consumers no longer have to bring mercury into their homes, business’s and other lighted spaces through the use of fluorescent lights.

Unlike incandescent light bulbs, which light up regardless of the electrical polarity, LEDs will only light with positive electrical polarity. LEDs produce more light per watt than do incandescent bulbs, and have an extremely long life span (usually about 50,000 hours). One manufacturer has calculated the ETTF (Estimated Time To Failure) for their LEDs to be between 100,000 and 1,000,000 hours, mostly depending on the operating temperature (the cooler the environment, the longer LEDs last). Fluorescent tubes, in contrast, are typically rated at about 10,000 hours, but in practical application, they only last about 2,000 - 3,000 hours. Incandescent light bulbs typically burn out every 1,000 hours. LEDs mostly fail by dimming over time, rather than with the abrupt burnout of incandescent bulbs.

LED lights contain absolutely no mercury or toxic chemicals, and conventional LEDs are made from a variety of inorganic semiconductor materials. They don't generate RF wavelengths that cause radio interference, or emit ultraviolet (UV) light -- so LEDs will not readily attract bugs and other insects. So what’s the downside you ask? Well, in fact – the LED is almost a PERFECT product, with one short-term exception… Cost! Sure, the cost has come down greatly over time, however it will still cost you $129 to replace a $20 recessed light fixture in your home or business. In fact, the issue should not be titled Cost, but instead “Short Term” cost, since even the cost is beneficial when stretched over multiple years. One recent estimate suggested the typical Normal Duty LED replacement lamp would last more than 25 years, or 50 times that of a standard incandescent. Figure in the cost of changing 50 lamps over that span – and the LED becomes a pretty solid deal.  

In a recent study by The Department of Energy, they’ve estimated that LEDs could reduce national energy consumption for lighting by 29% by 2025. That would save U.S. households $125 billion on their electric bills and would have a significant positive impact on our global warming, energy and emissions initiatives.