LEDs and Basic Stuff

Polar Ray Admin

To make LEDs work for general lighting purposes, they must be modified from their natural emission of light which is almost monochromatic. In that state, they are great for applications which use colored light, such as traffic lights, but are useless for general area lighting. In order to produce LEDs which are able to be used for general lighting purposes, white light is needed. White light is the type of light that is produced by incandescent lighting and even though incandescent light does not appear exactly white, it is called white as it is certainly not colored. Producing LEDs which emit white light can be accomplished by combining multiple monochromatic LEDs, using a phosphor on or near the LED source, or a combination of both. The methods used to produce white light from LED’s allow for the color tuneability that is one of the great features of LED lighting.

Efficiency is an overall hallmark of LED lighting and the overall efficiency of LED lighting is unparalleled in the history of lighting and, if expected potentials are met, by the year 2030 the energy use from general lighting will be half of what it is today. Less energy usage not only decreases the cost of lighting but the carbon footprint created by producing energy is also greatly reduced. The efficiency of LED lighting is measured in other ways as well. The lifetime efficiency is not only due to the LED technology that produces the light but the overall design features and inherent capabilities of the LEDs. Some of the unique characteristics which make LED lighting so advantageous and efficient for multitudes of applications include, not only energy savings and long life but also, nice cold weather performance, resistance to breakage and vibration, instant-on performance, dimming ability, lack of infrared and ultraviolet emissions, the ability to be tuned to different color temperatures, and the capability to modify any of the numerous properties that are able to vary and enhance the makeup of the emitted light in ways that were never available with any lighting technology in the past. Another part of the efficiency is also in the inherent design of LEDs, and that is that the light from them is directed in a specific direction, instead of producing light in all directions as with incandescent bulbs and fluorescent lighting. This reduces or eliminates the need for reflectors as used, and necessary, in other luminary technology. The advantage allows less loss of light which occurs within the fixture of a luminary that has a necessary reflector system. In fact, with the older lighting technology in troffers, downlights, and any light using a reflector system, it is not uncommon to have a 40-50% loss of light.

The energy efficiency is determined, not only by the design of the LED itself but, by the design of the unit it resides in. LEDs are quite sensitive to heat and they prefer an environment which is around room temperature. That’s not to say they won’t operate well in warmer temperatures, they will, but the design of the unit as a whole is what comes into play when controlling the thermal issues which can kill LEDs. Many lowered efficiency issues can come with poorly designed heat control, the most important being the loss of efficiency through the amount of energy consumed due to temperatures which exceed the sweet zone needed for the highest operational efficiency. Another property affected by incorrect thermal control would be the overall lifetime expectancy, which could be greatly reduced by continued operation outside the thermal limits of the LEDs. Lumen depreciation is also a result of thermal problems caused by excess heat generated at the LED junction. The heat must be controlled by either convection or conduction in order to maintain all operational design characteristics of the LED. Even if a product is designed using the best available LEDs, if the overall design is lacking the other engineering elements which make for the best environment for the LEDs to perform their magic, that magic won’t happen and the product will only perform at a fraction of what would be possible.

The light color itself and the colors it presents are key advantages of LED efficiency when it comes to the lighting of different areas in homes and buildings. Two main LED characteristics (metrics) that play into the color performance are the correlated color temperature (CCT) and the color rendering index (CRI). Both of these characteristics help determine how the light affects the appearance of color in objects. This is known as the color rendition and it can be quantified through the CRI and other recent metrics developed specifically from and for LED technology, including R9, which is a better fidelity predictor of saturated reds. The higher the CRI, the greater the excellence of the color fidelity in objects, and LEDs are capable of CRI ratings in excess of 90, which is pretty good – 100 is perfect and a minimum of 80 is highly recommended for interior lighting. The ability to tune LEDs to different CCT ratings (generally 2700K-6000K) allows for the area to be tweaked for the proper color of the output light. This characteristic helps set the wanted or necessary atmosphere for the area. Whether it be a living area or a working area, the ability to nicely illuminate the space in the correct color is a great plus in the comfort factor, in whatever task or activity that is intended to take place.

In order to ensure that you purchase LED products that are designed and constructed to meet the standards set by the numerous entities that dictate issues such as safety and other product associated standards, which indicate the high quality of the product, pay attention to the certification marks and listings. All those certification listings and proper design elements will be in place with products associated with all the well-known manufacturers and distributors.

 As always, if you have questions in regard to any of your lighting projects, please feel free to call Polar-Ray at 303-494-5773 to speak with a lighting consultant. Thank you for perusing our web site.