By Clifton Stanley Lemon
How many designers does it take to change a lightbulb? Answer: Does it have to be a light bulb? While this old joke lampoons the legendary persnickety design thinking personified by Steve Jobs and others, the response is quite valid. Who in the lighting industry today is asking this question or similar ones? Who’s coming up with compelling answers?
In Part 1 of this series, I explored some of the prevalent operating narratives in lighting today; in Part 2, I explored how innovation typically scales and spreads with certain combinations (stacks) of technologies and business models. In this essay, I look at the role of innovation in creating a platform; I profile a particularly promising innovation by my client QuarkStar; I describe its technical details, design potential, and cascading benefits; and I examine the role of imagination and inventing new narratives in the process of innovation.
Solid state lighting (SSL) has effected significant energy efficiency gains on a global scale, by any measure, a singular success with tremendous impact. For obvious and unavoidable reasons, chiefly the need to facilitate rapid LED adoption, we mostly replaced incandescent, fluorescent, and HID light sources in luminaires with LEDs. But so far, the impact of SSL has only been at the chip level (Figure 1 below) and has not extended throughout the lighting system of luminaires, power electronics, and controls.
The history of innovation shows that seeing a problem in a completely different way often sparks innovation. Rather than asking, “How can we adapt LEDS to lighting?” QuarkStar dared ask, “How can we adapt lighting to LEDs?”
Efficacy and Light-on-Target
In the early days of SSL, commercial viability meant efficiency – we rushed to optimize the lumens per Watt (LPW) of LEDs and never talked about fixture efficacy. LED chips reached and exceeded legacy light source efficiency levels many years ago, but we haven’t made a full pivot to talking about fixture efficacy. How effective and useful is the light produced by the luminaire?
A fundamental problem in lighting is to deliver “light-on-target”: light where you want it and nowhere else. Light emitted at undesired angles causes discomfort, glare, or light pollution. And a luminaire can be marketed as having a 200 LPW LED, but if only 50% of the light makes it to where it’s needed, LPW is an egregiously misleading metric.
Product vs Platform
“Platform” is a narrative-driven by tech companies like Uber, Apple, and Facebook. The best example of a product-based platform is Apple’s iPhone, which engendered the concept of “app” and an “ecosystem” of app developers. In Machine Platform Crowd: Harnessing Our Digital Future, the authors describe how thinking machines, platforms, and crowdsourcing are transforming our world, but this is not the sense of “platform” that I use here. The chance for an innovative lighting product being the basis for a platform like iPhone is not zero, but it’s still far from being realized. The hype about turning lighting into the backbone of building IoT systems has been a distraction and never focused on lighting itself. Let’s look at innovations that do that!
Here I use the term “platform” in a more practical sense to describe a product design approach crucially needed in lighting today: a system that integrates and optimizes LEDs and optics and allows a wide range of configurations and applications.
The Quarkstar team asked, “How can we condition and shape light to be pleasing? How can we deliver light-on-target most efficiently? How can we make LEDs not just equal to but BETTER than incandescents?” The basic efficiency problem had been solved in LEDs, now, the challenge was to make light more beautiful, acceptable, and affordable in all lighting markets.
LEDs are fundamentally, dramatically different from all preceding lighting sources: they are orders of magnitude smaller and brighter (see diagram below). With light sources so tiny, the team asked, “What happens when we scale down the whole light fixture?”
According to Quarkstar’s Bob Gardner, “The light distribution pattern is our real product, not the fixture. Starting with this premise, we saw that we could take a given distribution geometry as input and work down through the extractor to the light guide to the injector to the LED.” The team was literally thinking outside the box, streamlining the different layers in the system – separate housings, diffusers, and reflectors – integrating all of their functions directly into the optic. This innovation process became known to the team as “integrating down.”
“Integrating down is not only about miniaturization – being able to do the same thing in a smaller package – that’s where the lighting industry has been stuck. It’s about unlocking new capabilities that evolve from integrating several functions together in one package. The iPhone is the classic example of integration that allowed Apple to launch a global phenomenon. What we’re doing is far simpler than the iPhone but similar in spirit. We’re able to do things with light never before possible, driven by the inherent qualities of SSL,” said QuarkStar COO Jaqueline Teng.
Figure 2 below shows the integrated functions of the injector, a Compound Parabolic Concentrator (CPC), lightguide, and extractor. On the edge dimension, the CPC captures light from each side of an LED and herds it all in roughly the same direction. On the linear dimension, the CPC creates cones of light, which evenly mix the light from adjacent LEDs so that by the time it reaches the end of the lightguide it’s optimized for shaping by the extractor, which acts like a lens.
The Edge-X Platform
Edge-X offers something unique in lighting today, a fully controlled light path that delivers light on target. Its key innovation is not a single component but an integrated system of LEDs and optics that shapes light distribution in a completely new way. Virtually no wasted light means luminaire efficacy that almost matches LED efficiency.
LEDs turn electrons into photons very efficiently. But that’s only part of the solution – turning photons into useful light requires a different innovation. Many light-conserving strategies work at the chip level, but in a fully integrated system, the connection between the LED chip and the optics is optimized, enabling “precise sculpting and unprecedented control of light,” according to QuarkStar’s Eric Bretschneider.
The four elements of the Edge-X system are the LEDs; the injector; the lightguide, and the extractor.
LEDs – Edge-X is designed to work with conventional LED packages or with small Chip Scale Package (CSP) devices. The smaller the source LED, the smaller the optical system and luminaire can be. (QuarkStar is also exploring how Edge-X works with different kinds of emerging LED package designs). Edge-X was designed to be as LED-agnostic as possible in order to enable the widest flexibility and developmental possibilities.
Injector – The injector is a CPC with carefully calibrated curves that orient the LED’s light optimally before it enters the lightguide. CPCs work both for collecting photons or emitting and are used in solar photovoltaic, solar thermal technology, and other applications like automotive taillights.
Lightguide – The lightguide mixes light and transfers it to the extractor. Because of its high total internal reflectance (TIR) it optimally preserves the shaped light from the injector. As the injectors are positioned along the edge of the lightguide, the lightguide mixes and evens out light from adjacent injectors, as shown in the diagram. This design is fundamentally different from lightguides commonly used in industry-standard LED luminaires, which often have surface treatments such as dimpling that emit light from faces of the lightguide, resulting in wasted light.
Extractor – The extractor is where the final sculpting of the light occurs. When the light arrives at the extractor from the lightguide, it’s optimally mixed and is ready to be shaped. Extractors can be configured in a wide range of distributions (including asymmetric) and swapped out in the field easily. This edge extraction capability is unique to the Edge-X platform, which is covered by over 100 granted patents worldwide.
Edge–X delivered unexpected possibilities beyond solving the original problems. The precise control of light afforded by the platform delivers many complimentary benefits to manufacturers, designers, and end users. This integrated system gives the lighting industry a design language with which to realize new innovations.
Optimal and New Distributions – The Edge-X platform also enables a wide range of distributions never before possible with conventional optics and luminaire designs. In a photo below, Edge-X creates a beautiful, even, 16’ ceiling-to-floor wall wash, demonstrated at the Museum of Fine Arts, Houston’s Rich and Nancy Kinder Building installation (Figure 4 below).
Thermal Management – Edge-X provides excellent thermal management of LEDs by removing the light source from the heat source. This redefines how optics and housing can interface and how they’re controlled.
Eliminating Glare – Edge-X luminaires with two different distributions – one directional and one indirect – eliminate glare by keeping luminance out of direct line-of-sight and by softening the contrast between the light source and the surface it’s mounted on.
Miniaturization – the Edge-X approach allows the entire system to scale in sync with the size of the LED, which proportionately reduces the need for materials, attachment fittings, LED count and power, and space required to install the luminaire. As LEDs become smaller and brighter, the integrated LED/optical system allows much greater freedom and flexibility in both luminaire design and lighting design. Also, a smaller luminaire footprint leaves more space for electronics and controls.
Modular Manufacturing and Assembly – Edge-X is a highly modular platform that allows separate control and management of each component, allowing flexibility for manufacturing business models and supply chains. Separating the Edge-X lightguide from the extractor allows manufacturers to stock the basic assembled lightguide units and order different extractor configurations with distinct distribution patterns as orders get closer to fulfillment.
Customization – Another QuarkStar innovation is the Edge-X Design Advisor software, which takes a desired light distribution pattern as an input and creates specific injector, lightguide and extractor geometries to be fed directly into CNC and injection molding manufacturing sequences. This means a designer can easily create custom luminaires for a specific project.
Lighting Ceilings and Walls – In many applications designers are gradually moving away from downlight-only designs, which pose limitations in optimal lighting of spaces and people. Edge-X facilitates designs that can illuminate walls and ceilings as well as providing excellent directional distributions, sometimes with the same luminaire, as shown in the downlight below.
A Culture of Innovation
QuarkStar’s approach to innovation for Edge-X was ideal for the U.S. Department of Energy’s L-Prize Phase 1 competition, in which the company was a winner in 2022. QuarkStar easily met DOE’s stretch goals, which included optimal color rendering, thermal performance, lifetime, and high efficacy. QuarkStar also has filed over 500 patents in the U.S., Canada, Japan, and the E.U, and been granted 289 – a record that is on par with many much larger lighting industry leaders.
While innovation in lighting may appear to be stagnant, that’s only compared to the unprecedented rapid development of computers, electronics, and information technology, in the last 100 years. Despite the hype, other core industries such as steel production, agriculture, construction, and automobiles don’t show the same level of transformation – we shouldn’t expect the same from lighting.
QuarkStar completely redefined the problems in lighting, and solved many of them at once with the Edge-X platform. Innovation in lighting needs to be applied to the problems that affect everyone in the built environment: eliminating glare; making lighting easier to purchase, install, and operate; delivering light on target; and creating healthier more comfortable environments accessible to a wide range of people. These are the things that designers, building users, and building owners, and operators care most about.
In Part 4 of this series, I will share perspectives for key industry thought leaders and talk not about “future-proofing” but about “present-proofing” – how we can focus more on the business at hand to adapt to the challenges we face in the built environment.
Figure 1. Dramatic growth in luminous flux by volume. QuarkStar
Figure 2. Integrated functions of injector, lightguide, and extractor. QuarkStar
Figure 3. Comparative distributions of wall wash luminaires. QuarkStar
Figure 4. Edge-X enabled wall wash in the Museum of Fine Arts, Houston’s Rich and Nancy Kinder Building installation. QuarkStar
Figure 5. Dual distributions in Edge-X enabled downlights. QuarkStar
Read Part Two of this series here.
Read Part One of this series here.
Thanks for a good article. I usually get prickly when advertising is promoted as education, but Clifton is a gifted writer and futurist and Quarkstar has some profoundly interesting and potentially game changing technology, including the product that, like many of its predecessors from this company, is on the cutting edge of photonics. Clifton is one of the few writers in our field who can leverage an advertorial into a learning experience, which is what this series is all about. It’s good to see Quarkstar evolving – they have been around for more than a decade, seeking the right opportunities to re-invent lighting. Although this is an advertisement, Lemon is right – if successfully embraced by the lighting industry it could really change how we do lighting in many instances.