Tang Yao Hoong

Each year brings new breakthroughs in the lighting industry. Recent advances in materials and manufacturing indicate that 2013 will be a standout year, particularly in terms of unleashing creative potential. Achievements to date include manufacturing breakthroughs that have delivered record-breaking luminous efficacies at more accessible price points; enhanced capabilities in lighting materials and optics fabrication; and the exploration of new form-factors based on digital manufacturing and other processes.

Breaking Barriers
Advances in lighting materials enable the pursuit of ever-higher performance benchmarks. Manufacturers are incorporating new technological capabilities within appropriately retooled assemblies. For example, more-luminous high-voltage LEDs are now paired with smaller, higher-efficiency drivers than their predecessors, thus constituting a double breakthrough. The quest for higher efficacies continues into unprecedented levels when it comes to solid-state technology, with the promise of delivering desired illumination levels with fewer lamps and less energy.

Cree recently announced the attainment of 276 lumens per watt in white LEDs under laboratory conditions—a new industry record, besting the earlier milestone of 254 lumens per watt. This level of efficacy was reached using Cree’s SC3 technology platform, which boasts a redesigned package that has lower thermal resistance and a larger dome for enhanced light extraction. Meanwhile, advances in phosphors and LED chip architecture have resulted in better efficiency at converting electricity into light.

Also breaking records are manufacturer Green Ray LED Lighting, which has surpassed the fluorescent lamp efficiency barrier with a 173-lumen-per-watt LED replacement for T8-type tubes, and Philips, which developed a TLED (an LED tube) prototype with a 200-lumen-per-watt output. Though these higher efficacies do not guarantee better light quality—the lux can be inappropriately distributed—it does signal the capability to provide more illumination with less power, and therefore lower cost and energy consumption.

The NEWLED project, a research effort funded by the European Union’s Seventh Framework Program, aims to increase the efficiency of white LEDs based on the manufacture of superlattices—sophisticated packaging that allows for superior heat dissipation and light management. “Common light bulbs have a pretty low efficiency rating, and even the best current white LEDs in use only have an overall efficiency of around 25 percent,” said Edik Rafailov, the project’s leader and a physics professor at the University of Dundee, Scotland, in a press release. “What we are aiming to develop is a significantly more efficient white LED, which would be around 50 to 60 percent efficient. … The effects on overall energy consumption would be enormous.”

Manufacturing Makeovers
In addition to achieving new performance benchmarks, lighting manufacturers are also breaking cost barriers. This spring, Cree unveiled an LED A19 replacement lamp around the $10 mark, making a more accessible entry price point for consumers who are interested in switching to solid-state lighting. Based on the company’s LED Filament Tower technology, the lamp consists of an optically balanced source that provides 25,000 hours of illumination, according to the manufacturer. Cree achieved the cost reductions by implementing a higher-performance solid-state technology, notes John Edmond, Cree co-founder and director of advanced optoelectronics.

Further cost reductions in LEDs will be possible as manufacturing processes continue to be transformed. The use of active thermal management instead of passive aluminum heat sinks, dimmable drivers rather than nondimmable ones, and secondary optics that optimize the beam shape and distribution of primary optics will, in combination, allow for more precise control and energy utilization. According to the independent research and advisory firm Lux Research, headquartered in Boston, industry attention has shifted from reducing the cost of the LED package to that of the overall system, which includes optics, drivers, and thermal management. The lack of established standardization in LED technology has allowed manufacturers to develop incremental cost improvements in these areas. Because they aren’t beholden to a prescribed standard, they can pursue various methods to eke out performance gains.

Lighting manufacturers are also pursuing greater efficacies and performance by broadening the range of materials they employ. U.K.-based Plessey Semiconductors recently announced the creation of the first gallium-nitride-on-silicon (GaN-on-Si) LEDs constructed on 6-inch-diameter wafers. The large-diameter, GaN-on-Si process technology results in LEDs that are of similar quality to conventional sapphire and silicon carbide-based products, but can be made at a much lower cost. Compared with existing GaN-on-Si manufacturing, which uses 6- to 8-micrometer-thick GaN layers, Plessey’s approach uses 2.5-micrometer-thick GaN layers, thus improving material utilization.

New Directions
Advances have also come in three dimensions. The ability to manufacture optical elements via 3D printing has led to shorter product development cycles and a more flexible, iterative process for designing lighting fixtures. Scientists at Carnegie Mellon University are collaborating with Disney Research to develop 3D printed optics for interactive devices. According to a 2012 paper that the research team published in UIST (ACM Symposium on User Interface Software and Technology), “unique display surfaces, novel illumination techniques, custom optical sensors, and embedded optoelectronic components can be digitally fabricated for rapid, high-fidelity, highly customized interactive devices.”

Optics may now be printed on-demand using high-resolution transparent plastics at significantly lower cost than traditional manufacturing. These optical elements may also possess previously unachievable form-factors, such as the combination of multiple materials, structure-within-structure fabrications, and designs that integrate optical, as well as mechanical, structures. As a result, luminaires imbued with greater geometric and material sophistication are not only more affordable, but also made in less time and with less material and energy resources than ever before.

3D printing is not only transforming the manufacture of optical elements, but also the fabrication of entire luminaires. Sydney-based SandFlora Interior Lighting uses 3D printing to create LED- and CFL-based luminaires with sophisticated biomorphic geometries. The direct digital manufacturing process results in high-precision products with near-zero material waste. SandFlora’s Waratah collection includes coordinated pendant, floor, and table luminaires that are suitable for commercial or residential interiors.

The Do-It-Yourself movement is driving a lot of the experimentation in 3D-printed luminaires, with digital fabrication services like Shapeways, Freedom Of Creation, and .MGX enabling the rapid and relatively inexpensive production of complex fixtures. The Bloom Lamp, created by designer Patrick Jouin in collaboration with .MGX, is a 3D-printed table lamp with a dynamic shade. The lamp can extend its “petals” outward in order to emit more light or stay closed like a flower bud, releasing a soft glow through the opalescent shade. The Bloom Lamp is constructed as a single piece, including the hinges that enable the fixture to expand and contract.

In a similarly nascent stage of commercialization, OLED technology is witnessing creative approaches to its manufacture. LG Chem Power, which is developing the first high-efficiency, 80-lumen-per-watt OLED panels, plans to release the world’s first flexible OLED lighting panels this July. Each 0.2-millimeter-thick flexible panel will be 200 millimeters by 50 millimeters in size and weigh 0.6 grams. Delivering an output of 45 lumens per watt, the panels exhibit a hybrid structure of fluorescent and phosphorescent emitters on a thin glass substrate. They will be manufactured with a face seal, which is a flexible encapsulation technology that combines and protects the thin glass substrate with a metal protective layer.

As a testament to the company’s eagerness to test its new OLED manufacturing capabilities, LG Chem Power recently held an open OLED lighting design competition based on both flexible and rigid formats. The winning designs will doubtless push this evolving technology further.

These advances in technology and manufacturing reveal an industry in dramatic transformation. The outstripping of previous performance benchmarks, attainment of more accessible price points, and unprecedented material and fabrication capabilities give rise to an increasingly volatile environment—an environment in which it can be simultaneously thrilling and confounding for lighting professionals who are eager to maintain a technological and creative edge.