Adeline Chan, product marketing manager, Cree, Inc.
LED technology has been evolving rapidly over the years. From a performance perspective, lumen output and efficacy numbers have been improving. Other “areas” of the LED technology have also progressed such as thermal properties, substrate materials, light distribution pattern, LED capacity and forward voltages, as LED manufacturers continue to push the boundaries of what LEDs can do. As a result, the greatest challenge for the LED industry today is keeping up with the evolution of the technology and knowing how to take advantage of the latest LED component technology. Only when a design is built from the ground up with close collaboration between manufacturers of the LED, driver, optics and heat sink can an optimal system level performance be cost-effectively achieved. LED manufacturers can help lighting manufacturers overcome this challenge through the development of application-based LED reference designs. While the use of reference designs is common in other sectors of the semiconductor industry, it is far less common in the world of LEDs, as developing reference designs requires resources and extensive systems-level experience. Cree, Inc. understands the value of application-based LED reference designs and has produced the most published designs in the industry so far, demonstrating to lighting manufacturers what is possible with LEDs. These reference designs show lighting manufacturers how to design with LEDs and in the process, how they can go from prototypes to commercialized products quickly. The designs include commercially available drivers, optics and heat sinks from industry-leading suppliers to create an integrated, optimized system. In some cases, Cree makes available for download the CAD (computer-aided design) files of the different reflectors used for those interested in replicating the designs.
Anthony Toniolo, President, DDP Engineered LED Solutions
The biggest challenge for current LED technology is understanding the cost/benefit gap by users of the technology. Customers don’t buy products, they pay for the benefit the product provides. Designing a good LED-based design requires a thorough understanding of the customer’s application. For a disposable product, the design decision is fairly simple in that cost is king. However the LED design still has to provide some measure of performance otherwise, why have an LED at all? The more critical the LED design, the more attention needs to be paid to the key design quality factors such as optical design, thermal management and power. But the specifier doesn’t necessarily care about the intricacies of the LED design such as thermal management, fancy circuits, etc. He cares about the benefit the product delivers – maximum efficacy, minimum lumen degradation at the least expensive price. How the manufacturer achieves these benefits is up to them. A thorough understanding of the application helps the manufacturer control costs by not “over-designing” the LED product for the application.
James J. Wang, ECN Reader
Reduce cost of LED lights to parity with CFL bulbs and fluorescent tubes. LED chip cost and efficiency will likely follow a version of Moore’s Law. We integrate heat sink, power electronics with LEDs to cut weight with resulting fewer manufacturing steps, less consumption of raw materials and then mass produce on continuous manufacturing line to cut cost. Complete replacement with LEDs will begin once cost does not stop buyers,
| Mark Boomgaarden, Development Leader, Systems Engineering, Lighting Science Group
There continue to be several compelling challenges associated with LED technology, including technological encounters with thermal control and optical distribution issues. However, cost is still the greatest challenge. Previously, the thermal control took up the bulk of the lamp form factor. Newly minimized thermal controls have become small enough to mount inside the lamp form factor and now allows for gimballing. LED lamps with gimbaling now allow any fixture to now have functionality for aiming light exactly where the end user sees fit. Other benefits of this design are related to reliability; because the LED heat sink and light engine is not directly coupled to the lamp housing, the heat generated by the LEDs has been isolated so that it has a minimum impact on the power supply temperature increase. While these LED technological issues are ever-changing nad improving, performance and cost still remains an issue on mind of the consumer. It’s not enough that the product is more efficient in the long run it’s proving to the consumer that LED lamps are worth the investment over the less expensive and shorter lasting incandescent lamps. Manufacturers need to continue to shape their LED brands of lamps to appeal to consumers who remain skeptical of this products durability and longer life.
Greg Galluccio, Leviton Director, LED Business Development, Lampholder Product Management
The biggest challenge for current LED technology is control. Unlike traditional lighting where control compatibility can be easily predicted by knowing the type of dimming or switching technology being used, in the LED world control compatibility is dependent on the relationship between the control system and the particular LED driver being used in the luminaire or lamp. In today’s market, there are thousands of LED and no two are designed exactly the same way. Consequently, it is difficult if not impossible for a control provider to design a “universal” control that can be guaranteed to be compatible with a wide range of LED luminaires or light engines. The difficulty is compounded by the fact that “compatibility” is not easily defined. The range of issues that can occur when attempting to dim an LED product is extensive, and there is no clear consensus throughout the industry as to what constitutes a “compatible” control/driver combination. For example – if the product dims to 30 percent, is that considered compatible? How about 20 percent? Obviously, we would not consider a driver to be compatible with a control if there was a significant amount of flicker discernable at the low end of the dimming curve, but what if the system exhibits a low level of barely perceptible flicker? Finally, LED control systems perform differently given the size of the load on the control. A given control/driver combination may perform well with three to five fixtures connected to the circuit, but then exhibit problems when fixtures are added or taken away. Although many control providers are publishing compatibility data with certain LED systems, the burden of ensuring dimming control compatibility in the final application ultimately rests with the specifier. For commercial applications especially, it may be necessary to run tests on the systems prior to installation.
George Kelly, Technical Specialist, Avnet Electronics Marketing Americas
LED technology is now mature enough to challenge incumbent technologies in the general lighting market. Even so there are several technological improvements on the horizon that will make LEDs dominant over most of the general lighting market. No one knows where LED luminous efficacy will top out at. 200 lm/W, 250 lm/W? As LED luminous efficacy increases thermal management will become significantly easier and the quality of light will improve with tighter flux and chromaticity binning and CRI in the high 90s something fluorescents have never been able to match. While these inevitable technological improvements by LED manufacturers march on, the technological focus will shifts to the other components in the system. Key areas of development now include, novel thermal management systems, more efficient and reliable drivers, better dimming, color control/tuning, LED packaging improvements, and new optical designs to steer light where we need it most in ways not possible with traditional light sources. Wired and wireless controls that integrate LED lighting into home and office automation systems and alternative wiring systems and lower line voltages that will reduce total system costs especially in new construction, will all become major areas of focus.
To view more of the discussion, visit Part II.