Speakers say SSL has truly matured, light quality challenges remain (MAGAZINE)

April 2, 2020
The energy era is said to be over with LEDs, although efficiency does matter, reports MAURY WRIGHT based on Strategies in Light presentations, but the SSL industry must still pursue quality of light challenges and search for the next hot application.

Strategies in Light took place Feb. 11–13 in San Diego, CA with the conference including the typical mix of sessions focused on technology, market, and applications. The keynote presentations that we will focus on here were very compelling. The pervasive message was that the energy era is over for LEDs with companies that succeed needing to pursue quality of light or find new applications for solid-state lighting (SSL). The good news is that there is plenty of work to be done on light quality, and that effort should have a positive impact on prices and therefore the overall health of the LED and SSL businesses. Meanwhile, the innovators in the industry will also seek new applications.

Lawrence Lin, CEO of LEDvance, got the opening Plenary Session at the Strategies in Light Conference underway on Wednesday, and Lin was quick to address light quality (Fig. 1). Going into Strategies in Light, the company had introduced the Sylvania Natural Series of LED replacement lamps that leverage what the company calls TruWave technology to deliver a more uniform spectral power distribution (SPD). In his keynote address, Lin repeatedly referred to natural light as ideal for humans, essentially implying the new lamp family delivers such light.

Consumers discover quality

The presentation made some key points about both the technology and the market. LEDvance had fielded some market research among US customers buying replacement lamps. The customers did rate energy savings and long life as the most important attributes of lamps that they buy. But LEDvance also asked about a number of health-centric benefits, and around 50% of the respondents rated those health benefits very important. For example, one such benefit was support for an optimal sleep/wake cycle. The respondents also rated brightness as very important.

Lin, meanwhile, stressed the importance of natural light as delivering three specific benefits:

  • Reduced eye strain
  • More vivid color rendering
  • Clean and natural light

These benefits play out in applications ranging from education to retail to residential. Lin repeatedly stressed the fact that students or retail workers can see details with less eye strain under quality lighting — for instance, a retail clerk trying to read a small product tag. And we’ve long covered the concept that quality lighting and improved color rendering can increase retail sales.

Of course, the question remains how we define natural light or, for that matter, quality of light. There is no simple metric. But an examination of SPD provides some clues. And indeed Lin showed the SPD of a LEDvance 90-CRI lamp (Fig. 2). The SPD more closely matches the black-body curve than does the typical phosphor-converted LED. And Lin pointed out that LEDvance lamps deliver that SPD with efficacy matching typical lamps on the market.

Efficacy/SPD tradeoffs

But Lin was challenged during the Q&A session by a couple of experts in the lighting for health field. First, Dr. Martin Moore-Ede, CEO and founder of Circadian ZircLight, noted the near absence of blue energy in Lin’s SPD diagram that would be healthy at certain times of the day. Lin responded by saying the initial Natural Series products were intended for the broadest application possible. But he said LEDvance will deliver other lamps with different SPDs for specific applications that have different requirements.

Steve Paolini, founder of Telelumen, then noted that the LEDvance SPD was missing energy at both the high and low end of the human visual range. Paolini correctly suggested that LEDvance eliminated the energy as a tradeoff for better efficacy. And he pointed out that the 90-CRI SPD reduces energy significantly at 660 nm, which is the color of human blood. Moreover, he said lack of energy in the violet region would prevent humans from perceiving bright whites. Lin again said he believes the SPD of the new series will be very good for most applications and that other lamps in the LEDvance product planning would emerge for specific application scenarios with different SPD requirements.

Psychology and light

Following Lin’s presentation, Thomas Paterson, principal of design firm Lux Populi, presented a keynote titled the “Psychology of Light.” Paterson covered some territory explaining how the human eye and brain react to light, albeit with the end goal of approaching how lighting designers can apply light to help retailers, restaurants, museums, homeowners, and more encourage a desired response from a visitor.

“What happens inside the brain is an interpretation of space,” said Paterson. “The human eye is fairly accurate in terms of the little bit it captures. The human brain is extremely inaccurate, but what it does is that it puts together our best interpretation of the space around us.”

There are a lot of simple tricks that lighting designers and architects use. For example, if you put light at the end of a corridor, the corridor looks shorter. Paterson said the interpretation of a space goes directly to human emotion and that emotion is very important. He used as a simple example himself on a raised stage bathed in light in front of the Strategies in Light audience. The setting is meant to and generally does convey a person of importance.

“But what about a restaurant?” he asked. “Is it a business restaurant or is it a date restaurant?” But what lighting designers should be after, and according to Paterson what they often miss, is coercing the behavior that’s desired. In a men’s clothing store, for example, the lighting of a very nice jacket may entice a customer into the store even though the customer is more likely to buy a lower-cost shirt once in the store.

Vertical and horizontal

Paterson also discussed the concepts of vertical and horizontal illumination and made an example that uniquely illustrated his point. He had shown some images of an art gallery and discussed how wall washing made the space seem well lit despite the fact that the light levels by measure were relatively low. People don’t really notice the light on the wall but the brain perceives the space as pleasant.

He then asked how many in the audience ever swam laps in a 50m pool and got a number of affirmative responses. He said that 50m was a pretty good swim, although he remarked that we walk 50m on level ground without even thinking about it — he said it’s the length occupied by seven parked cars. But turn that 50m span vertical and you would be looking up at a 13-floor building and the perception of a much greater distance. He said, “The brain processes vertical and horizontal completely different.”

Back to a restaurant, Paterson asked the crowd to think about an early date with their significant other where the expectation was perhaps a meal that took an hour or 90 minutes but instead turned into a situation where you and your partner lingered for hours until closing. He quipped that light couldn’t guarantee such an experience but could certainly encourage such behavior. He showed photos of a restaurant where invisible pendants create a pool of light on each table. He used the moment to question the term “natural light” and suggested that really natural light isn’t sunlight or skylight but the aggregation of all the light humans have been exposed to over the course of evolution to this day. And he said what is natural for humans is gathering around pools of light (Fig. 3).

To further explain the ideas of perception and behavior, Paterson sought some volunteers from the audience who were shown photos. First up was a high-end jewelry store that featured an impressive entry and what from the outside appeared to be a very attractive interior — the lighting certainly looked well implemented. But the entrance did not look particularly inviting. Now the store is well known as are its prices. Paterson’s point was that the lighting design was meant to send a message that a customer entering the store should be prepared to spend a substantial sum.

Next, Paterson showed an after-ski restaurant located at a well-known winter resort. The participants agreed that the lighting provided a welcoming and comfortable look to the space. The mission behind the design was conversion of customer visits initially planned to be for quick drinks before dinner into drinks, dinner, and then more after-dinner drinks.

Looking to the SSL future

The Thursday keynote session, meanwhile, featured two speakers that were asked to project a bit into the future of lighting technology. First up was Jim Benya, principal at the Benya Burnett lighting design consultancy. Benya is never boring or afraid to express strong opinions, so the day got off to a fast start.

“One of the advantages of working as a lighting designer and illuminating engineer is that kind of every day in my work I have to figure out some way to take advantages of the new technologies that are coming down the pike,” said Benya. “And every now and then it really forces me to start looking out about five years or ten years or 15 years.” Benya admitted the looking-forward task is daunting. But he said there are clues to where the LED and SSL sectors are headed and that he would focus on those identifiable clues.

Benya started with a bold proclamation stating, “The energy era in lighting is officially over.” He mentioned Haitz’s Law, the famous projection by LED pioneer Roland Haitz that charted increases in LED performance and decreases in cost over time — a law first presented at Strategies in Light. Today the LED has exceeded the boundaries of Haitz’s projections. Moreover, Benya said that today, relative to building power density, the industry is operating at a level 90–95% lower than when building energy codes were first established in 1978.

LEDs or SSL changes?

LEDs do continue to improve, but Benya noted that the rate of improvement in efficacy has slowed. Still, he said there are continuous improvements in optics and other facets that lead to quality of light improvements. And given that his presentation was titled “Vison 2040,” he said he could not envision another light source supplanting LEDs in the next twenty years.

Next, he turned to luminaires and suggested that the future of such fixtures would be a lot more fun. He noted that the luminaires in the meeting space occupied a substantial amount of space. “That is going to change big time,” said Benya. Fixtures are called fixtures because they have to be affixed to a building system for reasons that include weight and electrical requirements, among others. LEDs won’t necessarily carry that burden forward. He asked, “What if I could change the luminaire in my office just by unattaching it and plugging in something new that I liked better?”

Such a future would fundamentally change the lighting sector. Benya envisions a plug-and-play world where electricians and facility engineers are not needed to change lighting in an office. Moreover, he said the concept of the Internet of Things (IoT), embedded sensors, and networked controls only add to the vision, although he is still not completely sold on full IoT implementations but instead on gated connectivity. He also introduced the concept of what he calls “perch and power.” Lighting continues to be a ripe spot to affix or perch something like a sensor that can also be supplied by lighting power.

Finally, Benya turned to DC grids. He said, “Every LED is a DC device, essentially.” AC/DC drivers are simply inefficient. DC/DC regulators in each luminaire would be far more efficient. Moreover, Benya said the building industry is moving toward a theme of resiliency where buildings themselves can continue to operate through loss of power and other disruptions. Benya reminded the crowd that batteries, which would be needed in such a scenario, don’t store AC power. Power over Ethernet (PoE) will be a key player, although Benya indicated that additional standards may be needed beyond where PoE stands today.

LESA research

The final keynote presentations continued the theme of questioning the future and carried an intriguing title — “The end of the SSL revolution, or is it the beginning?” The speaker was Bob Karlicek, who manages the Center for Lighting Enabled Systems & Applications (LESA), a research laboratory at Rensselaer Polytechnic Institute. Karlicek’s lab has been focused on LED and SSL technologies that might be ten years from commercialization.

Karlicek opened by noting that he had been in the LED sector for a long time and he proudly carried the title “chiphead” that was derived for work developing LED chips. Early on, he said his job was forcing SSL technology on unsuspecting lighting designers. He jokingly said he referred to those people as “brickheads” who made street lights, building systems, and such.

While Karlicek did peer into the future, his most sage advice may have been about the present or what he calls the last gasp
of the SSL revolution. Karlicek agrees with Benya that the energy era is over. There remains some potential to push LED efficacy, but Karlicek said cash-strapped LED manufacturers simply have no motivation to try and extend Haitz’s Law.

In terms of applications that could make a difference, Karlicek said lighting for health and wellbeing will remain important. He is also bullish to a degree on horticultural lighting as an important way to boost food supply. But he sees the rush by SSL manufacturers into horticultural lighting as unsustainable. He said too many people investing in horticultural applications don’t realize that Haitz’s Law will not be extended and that electrical costs will continue to gate controlled environment agriculture (CEA).

Riding building advancements

Karlicek, however, is more excited about what he called phase II of the SSL revolution and it is mainly focused on connected lighting. He does not see the lighting industry as driving the trend but rather getting a lift from the move by the building industry toward connectivity. He said, however, that energy efficiency is a non-factor, and the future is all about sensors and the data gathered.

The future according to Karlicek is a technology called Occupant Centric Control. He said sensors being deployed today might tell you someone is in a space but provide no real details — such as exactly where in the space and perhaps the reflected SPD from that person. Given that knowledge, a smart lighting system could truly tune a lighting scene specifically for the person occupying the space. Ultimately, systems must track number of occupants, movement, and more, and utilize machine learning to autonomously take action.

Karlicek also briefly discussed micro LED technology, which we will also touch on in the next section of this article. He sees micro LED technology supplanting other display technologies. But he further envisions the fusion of display and lighting systems down the road. That’s a topic we will be looking into in further detail this year and beyond.

Strategies Unlimited report

One of the hallmarks of Strategies in Light over the years has been the presentation of market data by the Strategies Unlimited team. For the 2020 event, attendees got the unique opportunity to hear Bob Steele make that market presentation, which featured some preliminary data from the new packaged LED report that will be available in March or April. Steele is a co-chair of the conference and was a co-founder of Strategies Unlimited and Strategies in Light.

Steele immediately jumped into the packaged LED market data, and 2019, as many of you may surmise, was not a great year. In the second half of 2018, manufacturers, especially in China, created an oversupply of components — especially in mid-power LEDs and to a lesser extent in high-power LEDs. At the same time, the on-again, off-again US-China trade war lowered demand somewhat in both general lighting for luminaires and in the automotive LED market. Most significantly, the market for such products in China dropped with the tariffs in place.

Initially prices dropped in Q1 2019 due to the oversupply. And then the oversupply and tariffs led to a further significant drop in Q4. Overall, mid-power LED pricing in Q4 was down 20–30% year over year. High-power LED prices were a bit more stable, having dropped 5–10%. The total impact was an LED market with revenues for the year down about 4% from the prior year.

2020 could rebound

Strategies Unlimited is projecting a more robust 2020, although we must warn that much of the research was done before
the world had grasped the seriousness of the COVID-19 coronavirus. We will again express our best wishes to all of those around the globe that are suffering from the coronavirus, and their wellbeing is ultimately more important than market data. That said, we still don’t know how the virus will ultimately impact the LED and SSL sectors.

The preliminary LED market data included a projection of low-single-digit growth for 2020, especially with indications that the trade war would end. Signage, led by directly-emissive LED video displays, and automotive applications will be the largest growth sectors. Lighting will grow moderately as a consumer of LEDs by revenue. Display and mobile will continue in a decline.

Fig. 4 depicts a summary of the projections. In 2019, packaged LED revenue was $15.7B (billion). Lighting remains the largest application by revenue and probably even by a wider gap in terms of components shipped. But price declines have hit the lighting sector harder than the signage or automotive sectors that tend to use higher-performance LEDs. The lighting sector is still expected to grow by 2.3% per year through 2024 while the overall market grows by around 5% to $20B.

Mini and micro LEDs

Strategies Unlimited is also preparing its first report ever on the mini and micro LED sector. We have published several articles on the topic recently, including a look at the technology demonstrated at the CES tradeshow back in January and a feature on the expanding use of LEDs in directly-emissive displays.

Revenue in the combined mini and micro LED sectors was under $200M (million) in 2019 (Fig. 5). But Strategies Unlimited does project an uptake in mini-LED-based TVs and IT displays over the next three years, with the mini LEDs serving as backlighting in a more granular fashion than you find in today’s TVs. Then in the last two years of the five-year forecast range, micro LEDs will become more prominent in directly-emissive TVs. The market is growing from a small base, but the growth rate is projected at 51% over five years to the $1.6B range.

*Editor's note: Please note that at the time Strategies in Light took place and when this article was prepared for publication, there was not yet a solid indication or further discussion of the extended impact of coronavirus on 2020 industry activity and markets. Comments that were made during Strategies in Light were based on information available at the time presentations were prepared and are reported as such here. LEDs Magazine wants to be clear that in no way have we, our event speakers, colleagues, or partners intentionally minimized or misrepresented the global health crisis.

About the Author

Maury Wright | Editor in Chief

Maury Wright is an electronics engineer turned technology journalist, who has focused specifically on the LED & Lighting industry for the past decade. Wright first wrote for LEDs Magazine as a contractor in 2010, and took over as Editor-in-Chief in 2012. He has broad experience in technology areas ranging from microprocessors to digital media to wireless networks that he gained over 30 years in the trade press. Wright has experience running global editorial operations, such as during his tenure as worldwide editorial director of EDN Magazine, and has been instrumental in launching publication websites going back to the earliest days of the Internet. Wright has won numerous industry awards, including multiple ASBPE national awards for B2B journalism excellence, and has received finalist recognition for LEDs Magazine in the FOLIO Eddie Awards. He received a BS in electrical engineering from Auburn University.