The Professional Lighting Design Conference (PLDC) in Berlin marked the first time, however, that I have seen such a practical and informed engagement by lighting designers with the potential to use LEDs in mainstream lighting applications. Perhaps Mars and Venus are beginning to come into alignment.
This was far from inevitable – the participants in PLDC are lighting designers and, unlike LED manufacturers, they have no bias in favour of one lighting technology over another. Indeed, PLDC is a rigorously professional and independent forum for debating, examining and explaining the art of lighting design, and it is led and attended by some of the world’s foremost design practitioners. If the LED industry is to achieve a breakthrough in mass adoption, this is the community we need to convince – and we as the LED industry have not traditionally done a good job of talking their language.
But in Berlin there were strong signs that the lighting design world now sees the LED as a viable technology for general lighting, although most of the discussion of LEDs came in the context of outdoor lighting, and museum and retail lighting. A measure of the demand for LED lighting in these segments was the number of products on show from traditional lighting manufacturers, such as Philips, Siteco, Disano, Fagerhult and Schreder.
This concentration on specific applications was reflected in the exhibition hall, where I saw new manufacturers in the lighting market with a strong technology background, such as Xicato, Braun and Hella, demonstrating outstanding LED luminaires. In particular a new street light design from Hella, which was installed in the street outside the conference hall, grabbed a huge amount of attention. We were told that this product went from initial concept to full production in less than a year. Hella, whose main business is in automotive lighting, perhaps has something to teach luminaire manufacturers in its speed of response to customer requirements. Its move into illumination applications may also be a sign of things to come from other companies not traditionally focused on illumination.
Inside the conference auditorium, lighting designers were in debate about the potential benefits to be gained, and the pitfalls to be avoided, in using such products. Dennis Koehler, of the School of Architecture at Fachhochschule Dortmund, spoke about the Masterplan city design, under which different areas in the city will have different kinds of lighting. This means it will, for instance, be easy to know if you are in a restaurant area, shopping area or bar area. This was a clear instance in which a lighting design team embraced LEDs’ ability to create new and better lighting effects. Interestingly, for Jean Sundin, Principal of Office for Visual Interaction, the implementation of LEDs even calls for ‘a new generation of lighting designers’ in order to exploit the subtle differences in colour and light intensity that LEDs are able to produce.
This new generation will, according to Gorm Teichert (Vice-President of Custom Lighting at Lighting Science Group), need to apply some understanding of the technology of solid-state light sources. He said that, if lighting specifiers want to avoid being disappointed in the long-term performance of LED lighting schemes, they must avoid relying just on the luminaire manufacturers’ warranties. They should also be aware of which key component parts the luminaire uses – such as the LED, the optics and the drive circuitry – and understand the lifetime ratings for each of these parts.
As noted earlier, lighting designers at PLDC embraced the LED as a light source in outdoor lighting, and also in museum and retail lighting. The most interesting reflection on these indoor applications came from Christopher Cuttle, a lighting designer from New Zealand, who told delegates that it is important that both the building and the merchandise or objects on display should be lit in accordance with appropriate photometric specifications that take into account the total lighting spectrum. The ubiquitous Colour Rendering Index (CRI) measure of light quality is, according to Cuttle, not always a reliable indicator, as it only takes 8 or 14 wavelengths into account, and not the complete spectrum. Indeed, research by Marc Fontoynant of the University of Lyon has shown that LED systems with a lower CRI provide a better subjective quality of light according to some users than traditional lighting schemes rated with a higher CRI.
In Cuttle’s view, it should be the lighting designer’s goal to match the lighting scheme to the precise colour requirements of the application – not simply to achieve a supposedly ‘natural’ effect by specifying the highest possible CRI value.
More than one speaker also discussed techniques for integrating daylight into interior lighting schemes. Daylight is a very attractive resource for lighting designers, both because of its energising effect, and also for sustainability reasons – the more natural light fills a room, the less electricity is required to power artificial lights.
You might think that, selfishly, the LED industry would oppose this trend, as our commercial goals require the installation of more not fewer artificial lights. But in fact this is a helpful new movement for the LED industry. LEDs are a point source: as such, they can be integrated well into daylight schemes, where broad area lighting is provided by sunlight, and task lighting and focused lighting of precise areas is achieved with LED luminaires.
In conclusion, then, PLDC (Berlin) demonstrated an intensification of the lighting design world’s engagement with LEDs. LED lighting offers such a wealth of opportunity to control and manipulate colour, light intensity, light quality, beam and direction, that it will take time for lighting designers to fully understand the power it gives them. In street lighting and museum/retail lighting, it looks like some bold steps are now being taken in the lighting design community, and there is much cause for optimism about that in our LED world.
The second Professional Lighting Design Conference took place in Berlin, Germany on October 29-31, 2009. The next event will take place in October 2011.