LEDs Magazine has closed the first day of its two-day virtual event, an online conference titled “Renaissance of light quality: SSL industry swaps focus from efficiency to architecture.” Professionals across all segments of the LED and solid-state lighting (SSL) supply chain logged on to learn how the LED and solid-state lighting (SSL) sectors can advance beyond the initial wave of LEDification and deliver quality light based on human experience, sustainable practices, and solid product integration.
Keynote speaker and notable lighting designer Teal Brogden, HLB Lighting, opened the program by “Telling stories with light,” as her presentation unfolded. Brogden noted that many years past, design teams often customized luminaires that would feature a mixture of fluorescent, incandescent, and LED sources in order to provide layered light with pleasing appearance, low glare, and proper light distribution. However, she explained, the new generation of SSL products lets “LED luminaires…get out of the way” and allow the entire built environment to shine.
Reviewing lighting designs from the iconic Los Angeles Airport (LAX) Central Terminal to the striking Peterson Automotive Museum, Brogden identified the technology enabling the aesthetic and artistic qualities in each project, showing how all things are possible when lighting follows architectural form and supports the purpose of the built environment. “As we think about layers of light,” she asked, “what is the story we’re trying to tell here?”
Moving from the dreamscapes built upon an SSL backbone to the light sources that bring them to life, Osram Opto Semiconductors’ director of materials research Juanita Kurtin gave details on the evolution of quantum dots (QDs) and what performance achievements have led the company to acquire the capability to produce such technology and further develop it for general illumination. Currently, the technology is meeting mid-power package needs, she said, and partially replaces the deep-red phosphor in an LED package. Kurtin divulged that the company’s QDs can achieve efficacy of 184‒185 lm/W today and are on a roadmap to deliver 192 lm/W within the next six months.
Future Lighting Solutions’ (FLS) worldwide technical director Patrick Durand gave the lay of the LED land in selecting appropriate light sources for human-centric SSL product development. He described current metrics for characterizing light for visual and non-visual responses, and related them to objectives targeted to the specific environment and application scenario. Using commercially-available LED data and FLS simulation tools, he compared the light source features and explained that each LED vendor has a different approach with regard to peak wavelength and spectrum, and may even have developed its LEDs with WELL Standards in mind. Specification can now be fine-tuned for human-centric SSL products, he stated.
In Part 2 of the session, OLEDWorks director of user experience Kathy Vaeth said while OLEDs have long been touted for their diffuse and glare-free illumination, now they have been evaluated to deliver less blue-rich light than typical phosphor-converted LEDs, extending the possibilities for human health and wellbeing in the built environment. She displayed before-and-after photos of an office project replacing traditional linear LED luminaires providing uplight/downlight with units featuring OLED panels for downlight and LED only for uplight. Vaeth said the OLEDs were turned down from the original spec because the diffuse light filled the room better, with fewer dark spots, so the initial light output was deemed “too bright.” The final result was improved illumination of the workspace from walls to work surfaces. She concluded that some additional influencing the quality of light experience with OLEDs included the ability to bring low-heat illumination closer to the user where it is needed, and the design freedom to place light in new spots and new ways.
In the last session of the day, speakers tackled various controls issues that directly impact light quality and experience. Pacific Northwest National Laboratory (PNNL) scientist Naomi Miller defined the trouble with temporal lighting artifacts (TLA), often collectively referred to simply as “flicker” but infinitely more complicated. Miller summarized the various sub-forms of visual disruption caused by inappropriate light output and control, demonstrating differences between direct flicker, the stroboscopic effect, and the phantom array effect, and described the limitations in measuring flicker in the lab. She observed that the lighting industry needs more evolved studies that can be used to further develop metrics and limit the mildly irritating to downright debilitating effects of flicker.
Next, Acuity Brands vice president of component solutions Chad Stalker approached quality-of-light factors from the LED driver and controls side, noting that all applications will require different definitions of the “goals for light quality.” An industrial plant, for example, may not require multiple channels for tunable output, but would place heavy demands on drivers to reliably manage power for safe, consistent lighting, whereas a high-end hospitality provider would benefit from dimming control, multiple channel/tunable output, and selectable dimming curves. He concurred that flicker is a major headache in any application and proper driver selection for compatibility with SSL system needs can mitigate such problems.
Finally, longtime LED specialist Steve Paolini of Telelumen took the last slot of the day to demonstrate how the SSL industry can expand how it executes tunability and lighting controls. Most illuminating were Paolini’s evaluations of natural daylight, which relied on measuring illuminance levels and CCT throughout the day in outdoor locations including Lake Como, Italy, and Yellowstone National Park. The purpose was to put a more realistic — albeit relativistic — spin on the mandate to replicate “natural light.” He observed rather wryly, “The variation in ‘normal’ daylight is enormous…and if we made electric lights like this, they would fail most standards the industry has set.” Thus, Paolini concluded, photometrics alone are insufficient to capture the daylight experience in electric lighting. More thoughtful, granular, tunable lighting control is required.
Join us tomorrow for the second day of presentations from the virtual event. Presentations will be archived and accessible on-demand for 90 days after the live event.
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