BURN like the SUN01 May 2012
Andrew English reviews state-of-the art lighting technology and wonders if the incandescent bulb still has a future
They used to call it "following the puddle," as drivers slowly picked their way along darkened country roads, behind a watery pool of light cast, invariably, by Lucas 'Prince of Darkness' headlamps. These days, lighting your way is big business, globally worth about €9.5 billion a year, with Europe's demands for ever more high-tech lamps taking the lion's share of that figure, estimated
at €4.6 billion.
For the market has started to split on broad lines between the developing markets – where the demand for low-cost transport means the incandescent bulb still holds sway – and Europe, Japan and North America, where bulb makers are using new car buyers as guinea pigs for the latest in a series of ultra-bright, low-energy technologies, which cost a whole
Father of the LED
Nick Holonyak, an electrical engineering professor at the University of Illinois, is widely credited as the father of the light emitting diode (LED). His initial discovery in 1962 only emitted red light, but, even back then, Holonyak could see the writing was on the wall for Thomas Edison's traditional incandescent bulb. In 1963, he told the Readers Digest magazine that incandescent light was doomed, although it's taken the automotive industry a while to catch up.
For a long time, LEDs were expensive and very much work-in-progress. The first practical uses were in seven-segment displays used in televisions, radios and calculators.
It would take serious development, however, and the discovery of white emitting LEDs in the late nineties, which mixed red, green and blue light, before they became practical for use in automotive exterior lamps.
"Customer benefits of LEDs are up to 70% less power consumption [compared to bulbs] and the freedom to push the style of light and more efficient packaging," says Mark Witschel, Ford's European exterior systems manager, adding, "they have a longer life, too." In fact, that life is almost the same as the vehicle's, so spare bulbs are a thing of the past.
Initial automotive applications were in brake lights, where the LED's fast switching times meant that following drivers could be warned faster than with a conventional bulb. Gradually, however, they have started to be seen in rear lamps, where the festoon arrangements are much loved by designers seeking to create a night-time 'brand identity' for their models. Premium car makers such as Audi, Mercedes-Benz and BMW are now introducing LED headlamps, but they are expensive and not just because they require unique heating/cooling arrangements. Since an LED throws little heat forward, the front of the lamp requires heating to prevent icing and it also requires cooling at the rear of the unit, as the LED is peculiarly vulnerable to overheating.
Just how much more cost is involved is illustrated by Rainer Neumann, lighting director for tier one supplier Visteon. "If you take the halogen [incandescent] bulb as 100%, in terms of cost," he says, "the high intensity discharge [HID] bulb is between 200-250% of that, and the LED in a premium car is between 500-600%."
Ouch! Do we really need to spend that much, finding our way at night? Neumann explains the imperatives that are pushing the more sophisticated markets to ever more expensive technical development. "The pressure is on for reduced energy consumption, increased life and lower carbon dioxide," he says. "The industry decided about eight years ago to invest in LEDs, especially for headlamps." Estimates of the CO2 saving possibilities of LEDs differ, with one General Motors' figure putting it as high as 6g/km, although Neumann says it is more like 2-3g/km. Trouble is, the current generation of LED headlamps are like works of art, not dissimilar to the very first 1899 Salsbury-Blériot acetylene lamps.
"We are like artists," he says, "designing each headlamp from scratch. At Bentley, for example, the individual investment is huge, with over 200 parts to assemble for each lamp. This is proving a major problem in bringing the technology to mass markets, as each lamp is like a Rolex version of a wrist watch." As a result, he quotes industry figures that indicate a very slow take-up of LED lamps. Around 2020, it is anticipated that at least 60% of cars will still be using halogen incandescent bulbs and a further 25-35 % will still be using HIDs, with a very small proportion using LEDs.
"We need to split the market," says Neumann. "We have started to produce LED modules with our partners, which are replaceable within existing headlamp glasses and can be produced in higher volumes." He names the Volkswagen Group and Ford, but there are others. While we have seen a number of lamp innovations over the years, including 'light-pipe' systems where the vehicle carries just one centrally mounted bulb, ducted around the car with fibre optics, LEDs are the real deal.
"I don't see light pipes making a comeback as viable technology," says Steffen Pietzonka, vice president of marketing for Hella's lighting division.
LED lighting is the major push at present, but he agrees with Neumann that the market needs to diversify between premium, high functionality ("which will stay complex and expensive") and a more basic LED market for the commercial and mass consumer markets.
So is there anything else out there in the pipeline? His company is watching developments in organic LEDs, which give a more homogenous light spread than semi-conductor LEDs. Organic LEDs are being researched by Audi, but pioneered by Astron Fiamm, an Italian company which began a pre-industrial phase of production two years ago. "There could be a general use for these LEDs," admits Pietzonka, "but we think it will be two to three years before the technology is ready to be used in interior or rear automotive lighting, as there are still issues with oxidation and stability."
Another technology seen at last autumn's Frankfurt show is the laser headlamp. Developed by BMW and Japanese firm Nichia, BMW claims that a laser lamp is 1,000 times brighter and100 times smaller than the current range of square cells in LED lamps, and that these class-one lasers have a 10,000-hour life span. "A laser is a nice approach," he says, "but it's not a successor to the LED. They're a nice thing and you can split the light, perhaps even activate a phosphor ball or a secondary light source, but I don't see them as a headlamp, and there are also cooling and temperature considerations."
Certainly, the capability of the LED – its better beam spread, longer life, lower energy requirements and ability to be tuned on the move to reduce dazzle for oncoming drivers – give it a huge lead over the incandescent bulb and even the HID. "There's a very strong direction towards the LED," says Pietzonka. "You ask what comes next, well slow down and wait for the mass-market applications. There are other technologies, but they will need a few more years."
There is, however, one area of concern over this seemingly inexorable march towards brighter, lighter, smaller and more efficient lamps, and that is the profitability of this supply industry. Hella already plans to produce its bulbs in Brazil, in partnership with local firm Emicol Eletro Eletronica. This is partly to supply burgeoning local markets, but also to reduce labour charges. Bosch has sold its lighting division to Italian firm Magnetti Marelli and Visteon is considering its directions in the lighting area. Earning a crust in an increasingly commoditised lamp market isn't easy, although Neumann and Pietzonka have high hopes for the future.
Big changes coming
"There will be a change in the next few years," says the latter. "At
the moment, the balance between electrical and mechanical components in headlamps is 30/70%; that looks set to change
to 50/50 by 2020. There will be a huge increase in electrical systems, software and a very high know-how requirement."
At the beginning of the last century, the automotive lighting industry suffered similar financial problems, and it was the heavy investment and technical development by giants such as Lucas for its King of the Road range of lamps that lit the path to the future. Could it be that this is just history repeating itself?
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