Inspiration | Innovate, illuminate – a lighting technology look-ahead, an essay by Iain Ruxton

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This article was first published in Lightecture's 'New Ways of Thinking', the edition guest edited by Mark Major.

Pontificating on the future of anything always feels like setting yourself up for a fall… I’m sure someone will be waving this in my face in five years’ time to point out how wrong I was way back in 2022. In any case, this is an interesting moment to think about the future of lighting technology.

For most of the 20th Century, the basic technology of lighting didn’t really change much. Application certainly did, and luminaire design developed enormously, but the fundamentals of producing light were still about heating bits of metal or generating sparks. And then, in the early 21st century, everything changed.

The LED revolution has genuinely been exactly that... a revolution. A seismic change in the technology of lighting and, as a result, in the lighting business. Yet here in 2022, LED isn’t revolutionary anymore… it’s standard. The steep curve of LED adoption has flattened. So, what might be next? What interesting developments lie around the corner?

Let’s start our crystal-ball gaze with light sources

With everything else in gradual decline, apart from a few niche technical or artisanal applications, is LED the only game in town? Well, at the moment, it rather looks that way. White light LEDs themselves are approaching a plateau in terms of technical performance. After the decade or so of incredibly rapid development, with huge yearly gains in output, light quality and efficiency, we are now really only seeing incremental improvements in efficiency and in lumen/mm2 density, both of which eventually hit the limits dictated by physics and which are not that far away. Colour rendering is already pretty close to its maximum, in general terms.

We will continue to see the small improvements, but more importantly, we hope to see the highest performance products coming down in price. CRIs above 95 are widely available but are still a premium product. CRIs around 90, however, are essentially standard. There is very little point in producing CRI 80 products any more. Before long, it seems inevitable that CRIs of 95-plus will be the standard.

Perhaps a broader adoption of quantum dot technology over the current generations of phosphors will help to squeeze a little more efficiency out of LED performance and might finally supersede lower CRI products, but other than that there doesn’t seem to be a great deal else to be done to radically improve LED as a light source… as far as I am aware, anyway!

I do, however, feel that the variety of devices available might widen in some respects, even as it narrows in others. The appearance of LED modules with deliberately designed off-black-body spectra a few years ago heralded all sorts of interesting possibilities, but doesn’t seem to have taken off in the way some of us hoped. Whilst there are devices with spectra intended for various types of food display, for plant health and even for fashion retail, the potential for more specialised spectra, and even for customised spectra at a commercially realistic cost seems somewhat untapped. Perhaps this will come back onto lighting technologists’ radar in the coming years.

The high-performance video projector market is utilising laser as a source for high-output, high-quality machines. Are these likely to cross over to general lighting? It seems unlikely – we rarely require huge outputs in a single source, and the technology is very expensive… Whilst they may turn up in high-end entertainment lighting products, it seems unlikely that there will ever be much point in making a laser diode downlight.

What about OLED? There was a lot of chat about OLED lighting a few years ago. And, to be fair, there is some product out there. But generally, OLED found its natural home in displays rather than general lighting. It doesn’t seem likely to return to contention.

So, at this point it seems reasonable to assume that there will not likely be anything new around the corner in terms of light sources. (You have my permission to wave this at me in a few years’ time when it seems ridiculous that I missed the new ultimate light source that came along in 2024.)

If future innovation isn’t in fundamental light sources, is it in the way they are combined into products? Almost certainly. We have seen the widespread emergence of tunable-white LED modules, which combine two different colour temperatures of light and mix them in differing ratios. We have also seen—though still expensive and more niche—products using four, five, six and seven colours of LED to produce a light with a very wide colour gamut, and the ability to produce white mixes which stay on the black body curve as they shift colour temperature. I foresee this type of module becoming more widespread and more affordable, whether it be a tunable white device with three or four CCTs of LED in, or the all-singing, all-dancing huge gamut colour change module. Part of making this real for commercial installations depends on the increased adoption of the DALI Type 8 definition, making control and integration of multi-channel colour-mixing lights easy and affordable, without the expense and complexity of entertainment-style controls and DMX data. After being around for a few years, DT8 is starting to gain some market penetration and will clearly begin to make greater impact in the next few years.

What about the components that we put in front of these light sources and modules? In the early years of the LED revolution, optical design seemed to be somewhat forgotten as manufacturers struggled with issues of output, form factors, and thermal design. In recent years, however, optics have been back big time, with lenses, reflectors and hybrid optics emerging that provide the diversity of light distributions that designers want, in varying sizes and shapes. It is a fair bet that optic design for LED sources will continue to generate innovative new products, which in turn allow luminaire designers to look at different form factors for lights, and potentially even new types of light that haven’t quite existed before. The use of high-quality 3D printing means that custom optics are a realistic commercial offer, even in small quantities. Variable optics, using technologies such as LCD diffusion and the “liquid lens” concept pioneered in entertainment lighting may offer interesting possibilities in some applications. Optics continue to be among the areas of lighting technology that show great innovation.

DALI Type 8 is not the only interesting thing going on in lighting control. Alongside optics in front of the source, controls behind the source are genuinely worth watching at the moment. After decades of lighting control being somewhat arcane and the controls supply model being based on the notion that clients would pay out £500 for an engineer to turn up just to change some scene levels or scheduling, this part of the lighting business is also undergoing a revolution. 

Clients and contractors accept that large lighting control systems require specialist commissioning. So do the lifts, the fire alarms, the HVAC, etc, etc, etc. However, it’s becoming increasingly unacceptable for small lighting systems to require such a level of support and for the owners of small and even larger systems to be unable to make any changes to their lighting without a specialist. In this age, when everyone has a fairly sophisticated computer in their pocket and full command of its use, it somehow feels rather backward that lighting control systems can’t present a user-friendly interface for commissioning and management.

Because the commissioning and programming of architectural lighting control systems has been a specialist task, and generally an “in-house” job by the controls manufacturers and their agents, the software tools have generally been relatively rudimentary: they’re made by system engineers for system engineers. This has had two outcomes. Firstly, the controls are hard to use for anyone who isn’t a control systems geek, as they were designed by and for control system geeks. Secondly, they often don’t take into account what lighting designers actually want to achieve, as they have been built around system architecture, rather than considering the way people actually want to control lighting. Now that the commercial pressure is to make lighting control accessible to facilities managers and even to end users, it’s time for the software to join the 2020’s. It must be thought out from the user backwards, not from the hardware forwards. The low-level technology should be concealed… and the actual behaviour of the lights over time should be the user’s sole concern.

Some (but not all!) of the lighting controls industry are finally addressing this. The more “smart-like” systems with minimal human input are now the holy grail, and they are imminent. They will be manageable with much more intuitive interfaces, drawing on the visual UX vocabulary of the smartphone apps that we all use every day. If I can use my smartphone banking app, find what I want on Netflix, buy stuff on Amazon, sell stuff on Ebay, and find a one-night-stand on Tinder, why can’t I set up, control and adjust the setup of my lights? What goes on behind the user interface in any of those examples is far more complicated than anything required in lighting control, yet they can deliver a consumer-friendly interface, while the lighting control industry still struggles.

This, in the next five years, is going to have to change. Controls companies will get their heads around this and release systems that are truly easy to commission, or at least to modify and manage. The minimal-commissioning systems that exist today will become more powerful, more scalable and hopefully more user-friendly. Systems will start to be about the user or designer defining the desired lighting effect, and all the low-level tech will be sorted out invisibly, automatically. There is no reason that the user should have to understand the underlying stuff. We’re all used to that with everything on the internet. 

A positive story here is the rise of wireless controls. Wireless systems have been out on the market for years, but the new generation of Bluetooth-based wireless systems, with wireless communication to the actual lights, is changing the landscape. From a modest start, the leaders in this field are now providing offers that scale and tackle many of the UI issues for commissioning and management, bringing the expertise from networking, mobile phone, and consumer electronic industries into lighting. Wireless will often have to be part of a hybrid system, if only to deal with the RF-unfriendly nature of many buildings. Nevertheless, these systems will clearly embody a powerful and essentially software-based option that shifts the focus onto user interfaces, commissioning tools, and networking connections and makes the setup of the actual light sources fairly straightforward.

Self-learning systems that adjust in keeping with sensor data over time are already here and will continue to get smarter. The “Internet of Things” distraction has receded—it was a meaningless phrase that no-one could define adequately, and it has now largely given way to actual ideas and solutions to real challenges. Why do I want a toaster and a washing machine that can communicate? What are they going to talk about? Unless they’re bitching about the fridge…

The IoT frenzy enables lighting tech to get on with being about lighting without trying to pretend that it’s going to be the network for everything. This is not to say that all the ideas of converged systems are not technically achievable. Technically, they’re not that hard. But commercially, they are largely impossible, as there are too many involved parties that like to draw a red line around their scope, with no interest in crossing it. Construction and land development is an industry resistant to change, regardless of what it may claim.

I like to think that there is an opportunity here to converge systems. Not with data, but with heat. LED lights inevitably generate heat that must be removed for the good of the light source. Could it be captured and shifted to where it is needed? Can lighting as a heat source be integrated with HVAC, not as control points, but as a heat network? Not just a “Smart Celling”, but a Unified Environment Ceiling, perhaps? The greatest waste product of lighting in operation is heat…. If that could be incorporated into a bigger-picture heat distribution system, it would all feel more sustainable. Again, this would require a lot of people to work together and the commercial interests may suggest that there’s no future in it.

I believe lighting control systems are going to change radically in the next decade. They must.

As a final area of exploration, we must acknowledge that the big issue in all building technologies right now is sustainability in the broadest sense. Lighting equipment consumes the largest part of its lifetime energy consumption whilst in use, so efficiency is important, but the bigger picture of energy generation is not something that most of us in lighting can affect. Every other aspect of sustainability, or circular economy, to put it in a manufacturing context, is within our influence. Progressive lighting manufacturers are already deeply involved in analysing their products and indeed their entire businesses from top to bottom, to work out the carbon impact, to figure out how to reduce or eliminate waste streams, to minimise shipping, to develop products that are genuinely as repairable, upgradeable, reusable, and as a last resort, recyclable. This will clearly have to be the future and any manufacturers who are not already beginning to take this seriously will fall by the wayside.


Let’s conclude. In 2022… what does the future of lighting technology look like?

There’s clearly going to be a lot of IT and interface design stuff coming our way. We’re going to see marginal improvements in LED light sources, but they probably won’t be earth-shattering. Cool optics that give us new possibilities. An increasing focus on sustainability that translates into product design and the entire process of manufacture and the criteria of specification. Though most of this probably isn’t that sexy, this last issue is absolutely fundamental. There are more lights in the world than any other type of electrical device… We in the lighting industry are inherently involved in the future of our planet.

The physics of light isn’t going to change—light will continue to move in straight lines until it bounces off something. Unless you can install a small black hole to bend it, which involves a number of challenges. Until we master that, the short-term future of lighting technology will have to focus on sustainability more than anything else. Yet this isn’t a constraint… It’s an enormous opportunity.