Lighting’s 10 great unsolved problems

 

The colour rendering index (or CRI) is a number on a scale of 0-100 that indicates how well a light source will render colours. For instance, a sodium streetlight, with an average CRI of 24, will render them badly, but a good fluorescent, with an index of 85, will render them well. However it’s becoming increasingly clear that the system – developed in the 1930s – is no longer fit for purpose. Strong reds aren’t included in thestandard eight sample hues and halogen, with a CRI of 100, is allegedly ‘perfect’. Scientists have developed alternative systems, but the industry simply can’t agree what to do. Prospect for a solution: Finding a solution is one thing, getting everyone to agree on it is another.

 

What the lighting industry won’t tell you is that the electronics that controls light sources and luminaires often isn’t good enough to go the distance. The space probe Voyager 1 may still be working 27 years after launch, but lighting equipment makers struggle to get a box of circuitry to last five years. This problem is coming into sharp focus with the advent of long-lasting LEDs: if your LED fitting fails, it’ll be because of the electronics. The capacitor is often blamed as the weak link, but in reality it’s just a factor. With some justification, manufacturers blame the heat in a sealed luminaire. Prospect for a solution: When customers are prepared to pay for quality – that is, never.

 

If those fancy MR16 LED lamps you’ve just installed flash when you try to dim them, then you’ve just stumbled across the lighting industry’s Achilles’ heel: dimming compatibility. The wall dimmer won’t talk to the transformer that won’t talk to the lamp. Why not? Because they’re all trying to do different things. The wall dimmer is happily chopping up the waveform, the transformer is desperately trying to maintain the voltage at 12V and the lamp’s internal driver is battling to keep the current at 350mA. And no-one is winning. Least of all, you, the customer. Prospect for a solution: ‘Smart’ dimmers offer hope, but we’ll have to wait for old tech to work its way out of the system.

 

Surely better lighting must mean less crime, mustn’t it? Well, not really. The industry is desperate for a document it can drop on a government minister’s desk that shows definitively that lighting cuts crime. The problem is that no such document exists: or at least, for every study that suggests lighting cuts crime, there’s another saying it doesn’t – or even (gasp) that it contributes to a rise. When improved lighting is installed in a trouble spot, you just can’t rely on criminals to do the decent thing and commit less crime. Sure, lighting can sometimes displace crime and make CCTV more effective, and it seems to dramatically reduce the fear of crime, which is no bad thing, but it’s not the panacea the industry wants. Prospect for a solution: Criminally small.

 

Fluorescent lamps work in a three-step cause-and-effect process: an electric current passed through the tube excites mercury vapour in the gas, and the mercury produces short-wave ultraviolet light that makes the phosphor coating on the inside of the bulb glow. Simples! The problem is the toxic mercury, which often ends up in landfill if the lamps are not recycled properly. Coming up with a suitable alternative has baffled the finest brains in the business – and now mercury-free LEDs have arrived, most have given up the search. Prospect for a solution: Looks like mercury will be with us for as long as fluorescent lighting is.

 

Inventors Humphrey Davy and Thomas Edison battled the problem of heat in lighting back in the nineteenth century, and you could argue we’re not that much further forward now. To a manufacturer, heat equals inefficiency – any electrical power you put into a light that comes out as heat as wasted. And although the arrival of LEDs has solved many of the thornier problems of lighting, heat isn’t one of them. That’s why tiny LEDs need massive lumps of metal to stay cool.But the industry isn’t even agreed about whether heatsinks should run hot or cold. Prospect for a solution: Not getting much warmer.

 

Each time the biennial lighting show in Frankfurt comes around, the word is put out that ‘this is the year that organic LEDs come of age’. Except that they don’t, and we’re told to come back in two years. The big manufacturers have invested millions in OLED research in the hope that it will be a complementary technology to LEDs and now no-one wants to admit that the latter can do everything the former can do three times as efficiently and at a fraction of the price. It’s a shame: the prospect of windows that turn into lights at night is a tantalising one. Prospect for a solution: The answer is always just over the horizon…

 

In case you missed the memo, the lighting control industry is going wireless. Hurrah! Yes, that’s right, just when you’ve got your head around Dali they go and change it again. And as you’d expect, it ain’t simple. In fact, it’s bringing with it a big problem: a format war. Dali was a (pretty much) widely agreed standard for wired lighting control, but there isn’t one for wireless. So which flavour do you want? Wi-Fi, ZigBee, Bluetooth, wireless DMX, a proprietary system? Hurry up! As you’d imagine, each has its own benefits, limitations and security issues. Who said specifying lighting was easy? Prospect for a solution: Call us when the format war’s over.

 

For decades, lighting professionals and academics have known that blue light is the Special One. The trouble is, no-one is agreed on what exactly is special about it. We know it has a unique effect on the human body, but where that research points us isn’t yet totally clear. In certain circumstances, it’s good for us (it can help us stay alert, for instance), but at other times it’s hazardous to health (in high doses it can damage our retinas). If we can get definitive research and establish exactly how blue light can help us, then it will inform the lighting of the future. Prospect for a solution: There’s (blue) light at the end of the tunnel.

 

Because people buy lighting for their homes, they think of lighting in certain ways: it’s a simple science, lights are cheap commodities, you only need one light per room, operating costs don’t matter, the visual effect isn’t important. You can see the effects of this mindset in any retail area. The industry has tried to educate the wider world about paybacks, operating costs, colour rendering, glare, design and control but it’s had limited success. The problem is that lighting is a complex science (and art) and it doesn’t lend itself to soundbites. Prospect for a solution: We’re working on it.