标签：LED lamps

Is the overall production process of LED lamps contrary to the energy-saving purpose?

It is well known that LED can maintain a normal working condition by consuming very little energy, emitting similar light (same brightness) as incandescent lamps does. But this is only a small part that known by us. In March of 2011, researchers from Carnegie Mellon University published a LED-related report. In this report, researchers advanced different ideas on the energy-saving feature of LED lamps. Indeed, LED lights can save more energy compared with other traditional lighting sources. But some researchers also pointed out that taken into account of the energy consumed during the production process, LED lights may not be as so energy-saving as our expected. The entire production process of LED lamps actually takes a lot of energy. According to foreign media reports, the production and recycling process of LED lights consumes even more energy than ordinary bulbs, which makes the energy-saving feature of LED lighting products exist in name only.

 

Is the overall production process of LED lamps contrary to the energy-saving purpose?

 

In fact, the higher the demand, the more energy wasted during the production process. Assumed that the production process of LED lights consumed much more energy than incandescent lamps or compact fluorescent lamps, the energy-saving function during their service life is thus meaningless.

 

In addition, LED light source has another two features which will increase the energy and materials consumption during the production process: small size and easy to control. These two features will definitely lead to diversified fixture designs. Unlike incandescent lamps and compact fluorescent tubes, whose appearance is limited by properties of their light sources. In this condition, manufacturers need to use more energy and materials to achieve a diversified design effect. From the view of daily life, indeed, LED Panel Light source could bright more colorful visual experiences to the world in the future. However, whether it is valuable to achieve this effect in the cost of consuming more energy and materials still needs deep considerations.

 

In summary, the overall production process of LED lamps is contrary to the energy-saving purpose. In order to save more energy during the production process, more studies and researches need to be taken. Manufacturers and research institutions need to enhance the cooperation. After all, LED light source always emphasized the importance of energy saving and environmental protection.

How to estimate the general lifetime of LED lamps

Is Lumen maintenance rate the only parameter that determine the lifetime of LED lamps? Normally, LED lights are composed of dimmers, power supplies, LED modules, drive components and cooling sections. These modules are connected in series or in parallel within the lamp body. Each module has its own function and reliability. The fault of anyone of them will cause the failure of the entire lamps. Just like the short board effect, the shortest board determines the capacity of the bucket. The one with the shortest lifetime among these modules will determine the service life of the lamp, totally different with traditional incandescent lights. If we treat LED lamps as electronic products, which parts are usually the main reasons for the failure of the lamp?

Is Lumen maintenance rate the only parameter that determine the lifetime of LED lamps?

Common failures of LED lights include: unreasonable cooling section designs, over-load applications, faults of driver circuits, power supplies’ failures and bad components or compartments. Failures frequently happed on electronic appliances will also occurred on LED Panel Lights. These defects can be solved via the laboratory reliability tests for electronic appliances. Another failure is usually caused by the defect of electrical characteristics. Take LED lamps for example, defects of electrical characteristics include: the lumen maintenance rate, color temperature variations, shift of power parameter offsets, etc.. Environmental reliability tests are more accurate for these defects. Therefore, from the past experience of reliability tests for electronic products, LED lighting products should also follow the traditional environment and reliability tests designed for electronic products to verify their reliability and service life.

 

As the new-born 4th generation lighting source, LED has just been touched or used in many countries and regions all over the world. Thus, it is not easy to find a large number of fault data of them. A recent large-scale failure data happened in Ellwood City, Pennsylvania, in the eastern United States. According the statistics, among the failure records of 5400 pieces outdoor LED lighting applications currently used in Ellwood City, 59% is caused directly by faults of power supplies/drivers, 31% is caused by insufficient heat dissipation, 10% caused by bad LED components. Thus, for outdoor LED products, environmental simulation tests and service life tests are more important. Only take the lumen maintenance rate into account will bright about huge errors.

Does the lumen maintenance data can represent the service life of LED lamps?

There are two main problems in current LED lighting market:

 

The first one: unclear identity. According to the test of ITRI industry, more than 50% LED bulbs in the market are insufficient in output luminous flux as they have been marked. It is estimated that measured results will be 10% less than the value given out by laboratory experiments.

 

Does the lumen maintenance data can represent the service life of LED lamps?

 

The second problem is the different quality. Currently, there is no unified standard to provide clear definitions to the relationship between prices and qualities. In most of cases, customers might spend a lot of money but did not obtain the corresponding high-quality products. This situation made buyers from other regions, like Europe and the United States paid more attention on the identity and quality of LED lamps/bulbs.

 

Does the lumen maintenance data can represent the service life of LED lamps? At present, the most official representative standard related to the service life of LED bulbs in the LED lighting market should be the LM-80 specification released by the Energy Star (U.S. Environmental Protection Agency) for LED Lamps. However, a number of different voices now have been found in North America. Some experts call on the abolishing of LM-80 specification immediately since it is not accurate as people expected in estimating the service life of LED bulbs. At least, it should not be the only specification for that.

 

In fact, in 2006, the U.S. Department of Energy Quality Working Group for Solid State Lighting (SSL) invited 32 LED experts and conducted a series of deep discussions about the reliability and lifetime estimation methods for LED lighting products. In consideration of the LED technologies at that moment, it is proved that lumen maintenance (L70) will be the most representative and most reliable specification for determining the life time of LED lamps. The light attenuation of LED lights is step by step process, which is too slow to be sensed by human. In the early stage of light attenuation, people can hardly recognize their lamps become dimmer. Not until the light attenuate to only 70% of the initial light intensity, the lost brightness of LED lights can be noticed. Thus the working group of U.S. Department of Energy Quality Working Group for Solid State Lighting suggested that L70 should be the only standard of LM-80 specification in determining the lifetime of LED lights, including LED bulbs.