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Six LED challenges that still remain

-July 25, 2013

While LED based solid-state lighting continues to gain ground, and several major challenges have been solved, some still remain. Energy savings and the savings that a long product lifetime brings certainly have spurred adoption in a long list of applications. Cities, sports facilities, retail, medical, residential and industrial use, are all on the rise. The move to LED-based solid-state lighting is gaining ground based on the promise of energy savings and long lifetime. Six key challenges are:

 

(1)  Dimmer Compatibility

LED drivers that implement digital dimming analysis have greatly improved performance over analog predecessors, helping to ensure compatibility with a much wider range of dimmers.  However, issues still remain, due to the broad range of existing, installed dimmer types, including TRIAC dimmers (leading-edge, trailing-edge, electronic) and 0 to 10V linear/PWM dimmers found primarily in commercial installations. The newest digital LED drivers can analyze the specific dimmer type, apply the optimal algorithm to adapt, eliminate flicker and maintain high efficiency.   

 

(2)  Light Flicker

Unlike incandescent lighting, where the tungsten filament element exhibits a long time constant, LED lighting responds instantly to changes in drive current, so current ripple and supply glitches will result in light flicker. The issue of flicker is still often glossed over by manufacturers but it is still a challenge.

 

(3)  Color Temperature (especially during dimming)

Consumers are accustomed to incandescent bulbs, which have a color temperature that “warms” as they are dimmed. Warmer light is associated with the ambiance in a dimmed environment and is what consumers naturally prefer. Most dimmable LED lighting today results in a dull, harsh white light.  While this is an improvement over the “yellow” that we lived with only a few years ago, it is not yet what it needs to be.

 

(4)  Thermal Management and Operating Lifetime

One of the claimed benefits of solid state lighting is lower total cost of ownership, primarily based on longer operating life, which reduces replacement costs. SSL manufacturers claim typical operating lives of 20X to 50X that of incandescent bulbs. However, poor thermal design and management can dramatically reduce the actual operating life well below what is claimed in lighting marketing literature. The temperature inside a closed lighting fixture can easily rise above 60°C and at these elevated temperatures, the passive components in the LED driver circuit, including electrolytic capacitors, will see reduced operating lifetimes and could result in a thermal runaway condition. LED drivers with robust thermal management can mitigate this problem and help SSL manufacturers ensure a predictable and safe bulb operating life.

 

(5)  Cost

The cost of LED bulbs continues to reduce and is already approaching a point acceptable to consumers. The ongoing education of consumers on total cost of owner ship, especially as it relates to lower replacement costs and lower energy usage will gradually address the perceived cost issue. Also, incentives provided by government entities and utility companies will provide additional motivation for consumers to move to SSL lighting and experience the benefits directly.

 

(6) Confusion

Change happens slowly. Many LED products exist and are marketed to a confused public used to paying pennies compared to tens of dollars per bulb. While cost is an important issue, so is how to select a bulb for a particular application. What It may be that the market is just evolving extremely rapidly and knowledge and perceptions will catch up, it seems that companies would benefit by doing more to bring the slow-to-change public along.

 

Can you add other challenges to this list? If so, weigh in…

 

 

Related content:  Why does flicker matter?

 

 

 

 

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