Many of the largest names in the LED industry now offer modular light engines, alongside specialty vendors that have nurtured the segment. In many cases, simplicity of system design drives solid-state lighting (SSL) manufacturers to utilize modules. But the module makers believe that the technology can also deliver superior performance, especially in areas such as color consistency. The unanswered question in the segment is whether the Zhaga Consortium standards will enable the vision of standardized interchangeable light engines that deliver benefits from the supply chain to field service/upgrade of luminaires.
SSL manufacturers face a shortlist of questions when considering whether to use a modular light engine in a product or to design their own light engine. If the module route is chosen, the development team must then decide whether to buy a module with an integrated driver, choose a separate off-the-shelf modular driver, or design their own. The other decision points include criteria such as modules that use phosphor-converted white LEDs or modules with blue-pump LEDs and remote-phosphor optics. And the last decision point is whether standardization and Zhaga are beneficial to the project. This article will discuss all of those questions.
First, let's address what qualifies as a module or modular light engine. The list includes products ranging from a circuit board with LEDs installed to more finished modules in an enclosure of some type. Modules are available for products ranging from streetlights to ceiling troffers to track heads and more. Modules can require tools and fasteners to attach into a fixture or in cases can be snapped or twisted into place.
Why modules?
Traditionally, modules have been thought of as a way to develop products faster in the electronics industry, whether the application at hand was a computer or an LED-based luminaire. In the SSL segment, larger Tier 1 companies have tended to design their own light engines for each product, whereas smaller companies were more likely to choose a module to hasten the development process.
The projected demand and cost of a product also comes into play. Paul Scheidt, product marketing manager at Cree, describes how that company offers customers three levels of engagement at the luminaire design level. When a company isn't sure a project can justify a custom design, Scheidt said that a module is a good option that reduces engineering cost upfront but might result in a slightly higher bill of materials (BOM) in the production phase.
Chip-on-board (COB) LEDs are easier to design into a custom light engine than individual emitters, according to Scheidt, and fall into a middle ground in terms of functionality and cost. Scheidt said that individual emitters properly applied generally perform the best, and in high-volume luminaire production they have the lowest BOM but the highest upfront engineering costs. Ironically, some people have the mistaken idea that COB LEDs produce more uniform light than individual emitters. While it's true that COB LEDs are easier to work with, you can better control the light with smaller sources when a product is designed properly.
GE Lighting reports that customers of its Infusion modules follow the traditional thinking thus far. John Koster, product manager for LED modules, said that Tier 1 customers generally find a module too expensive, although he admits that GE focuses on high-performing products more than low cost with Infusion. Koster said that GE has around 20 OEM customers for Infusion that he described as Tier 2 players in lighting.
Changing the decision point
Dave Lidrbauch, product marketing manager at Osram Sylvania, sees the justification changing for choosing the modular route. A key challenge for SSL manufacturers is the pace of change in LED components. Lighting manufacturers want to use the latest LEDs and deliver top efficacy. But the manufacturers also need to offer a product today, and a product two years from now that may use different LEDs, with both looking identical in terms of light output, color temperature, and CRI. Lidrbauch said that you can buy a module from Osram, and Osram will ensure the consistency in its next-generation module.
As for customers, Lidrbauch said Osram is shipping a module in high volume to a Tier 1 customer. Moreover, he said that Osram often works with a close luminaire partner in developing a new module, thereby assuming much of the risk in the design. He recounted one project where Osram had to change the LED being used in a module deep in the development cycle with the customer/partner counting on the module. But Lidrbauch said the process was transparent with the customer involved in the decision. And testing had revealed that the chosen LED would not deliver on the customer's performance requirements.
Therein lies another issue with light-engine design. The LED industry has made great progress with LED manufacturers performing LM-80 testing and providing TM-21 projections on lumen maintenance. But quite often, a development team will need to start a design before there are the 6000 hours of component testing in place required for an LM-80 report. Lidrbauch said, "Designs are almost always started before LM-80 is complete." Still, the latest LED technology promises the best efficacy, lifetime, and color and lumen maintenance. Lidrbauch's message is leave the light engine design to experts who do that job every day.
No comments:
Post a Comment