Lighting and LED manufacturers discuss the state of technology

While it's clear that the lighting industry is rapidly transitioning to LED sources for most mainstream product types, little else remains clear as what has been a staid industry rides the semiconductor rollercoaster for the first time. With The led street light with solar panel and solid-state lighting (SSL) vendors preparing their wares for exhibit, we asked a number of industry executives to share their views on the state of lighting technology. The following roundtable includes insight into areas such as dimming and controls while also covering market developments and the evolving LED light sources.
Because we hoped to discuss both the light source technology and developments in lamps and luminaires, we specifically looked for participants with knowledge of both the enabling component and SSL sectors. The participants included Chris Bohler, director of innovation in Eaton's Cooper Lighting Business; Uwe Thomas, vice president of product management at LED Engin; Brian Terao, director of solid-state lighting for Osram Opto Semiconductors; David Bay, corporate engineer at Osram Sylvania; and Gary Trott, vice president of product strategy at Cree.
Illumination in Focus: What are the most important market and technology trends that you see in mid-2014 in regard to LED-based lamp or luminaire design? We'd like to hear about topics ranging from product design strategies to features of the end product to the enabling components and technologies embedded in SSL products.
Gary Trott: It really feels like - for a lot of the big applications such as residential and commercial lamps, street lights, area lights, downlights, and troffers - that LEDs are a no-brainer now. The adoption is happening at such a rapid rate both for us and the entire industry. There are so many companies heavily engaged. I was on a long drive today and saw a somewhat rundown convenience store; and I look up and see one of our CPY250 LED canopy fixtures. When I see that, I know LED lighting is mainstream. It's no longer a question of "Should we do it?" but "Which LED product should I use?"
Chris Bohler: Historically, SSL penetration has primarily been driven by lumens, lumens per watt (lm/W), and lumens per dollar (lm/$), as long as a minimum threshold on reliability and overall product quality could be met. More recently, color quality has reached center stage as flux and price points have overcome the minimum threshold of acceptability in the general lighting markets. Although continuing improvements related to LED and LED systems flux and efficacy will be necessary, other lighting metrics like color rendering index (CRI) greater than or equal to 90, R9 greater than or equal to 50, and correlated color temperature (CCT) variance, and variance over life, will continue to come into play. To a large extent, these needs are being driven by organizations at the state and federal levels through standards activities such as California Title 24 and related quality standards.
Additional technology trends are being seen in lighting controls that go well beyond simple dimming functions; networked communications in which the lighting fixture is an inherent part of the communication chain; and integrated structures that truly allow for both the optimization and minimization, from a real estate and complexity of design standpoint, of product solutions based on SSL and digitization technologies.
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David Bay: For LED screw-based lamps, manufacturers are trying to maintain key product performance attributes, while implementing changes in form factor, materials, system thermal management, manufacturing process, and product ranges while reducing their costs. Similarly, manufacturers of LED luminaires are re-evaluating their product's bill of materials (BOM), form, fit, function as well as the value chain of their product's use cases. Beyond luminaires continuing to be efficient and effective deliverers of light, one should expect future digital-lighting products to include functionalities heretofore assigned to non-lighting functions - for example, information technology, communications, security, etc. A natural result of such luminaire function-creep will be for lighting to evolve away from being a technology island within a building and bringing it closer to the information technology, energy management systems, building automation systems, and security systems, and functions of today's building and campus environments.
Uwe Thomas: From the led street light supplier component perspective, smaller source sizes increase flux density, enabling smaller beam angles with small secondary optics. Chip-on-board (COB) LED flux densities have reached levels that only multi-chip emitters could achieve in the past. The higher flux densities and the low cost for COB products make them attractive products for small-form-factor, narrow-beam downlights or tracklights in directional lighting applications.
New high-current chips deliver up to 3-A/mm2 current densities and much reduced droop characteristics. These chips double the flux density of today's COB technologies but require a robust package that can handle the thermal stress and conduct the heat efficiently.
Brian Terao: For lamp-based LED components, we see increasing use of high lm/$ devices to continue to drive out costs - for example, products such as mid-power LEDS and small COBs. COBs, meanwhile, enable luminaire designs to have a single source appearance and reduce accessory size and cost, while providing the center beam candle power (CBCP) punch specific luminaires target.