LED Light Control Units from Continental

VIENNA, AUSTRIA – August 11, 2009: Light-emitting diodes are making inroads into car and truck headlights. Whereas LEDs were previously used primarily for secondary functions, like daytime running lights, taillights, or flasher signals, they are now also increasingly used for low-beam and high-beam driving lights. Unlike conventional halogen light bulbs, LEDs require complex control electronics that oversee all light functions. Continental is a pioneer in the development of such systems. With its new light control unit it is now fast-forwarding a changing of the guard in the direction of better vision and enhanced safety. The first production start-up dates for the new car and commercial vehicle electronics systems have already been set.

Much to be gained from LED technology
Light emitting diodes offer a host of advantages over light bulbs or xenon headlights. In addition to providing designers an unique and unmistakable light signature, they also work more efficiently and longer. Their energy consumption is much lower; they are immune to impacts and do not have to be serviced.

For the bright shining diodes to fully exploit their advantages, however, electronic controls are needed. The reason for this is that unlike conventional light bulbs, LEDs cannot be fed with power from the on-board voltage supply. Electronics are thus needed to monitor the on-board voltage supply. They control light intensity by means of pulse-width modulation. As long as LED technology is used solely for the signal lights – i.e. the blinkers, the position lamps or the rear light – this was a relatively trivial concern. Now that LEDs are also being used in adaptive front headlights, however, the electronic controls have to deal with a slew of new coordination tasks.

Continental has thus come up with an innovative light control device capable of centrally governing all light functions. The electronics in this first stage of development are designed to accommodate a total of eight light looms. These individual LED groups can be individually controlled, making it possible to get by more or less without any additional mechanics in shifting to the illumination appropriate for a given road situation. The effect is far better than anything feasible previously with even the most sophisticated mechanical systems. Special lights for driving on motorways or country roads, a smooth transition from low beams to high beams, perfectly illuminated curves, or enhanced vision at intersections – Continental's light regulator provides all of that in just fractions of a second, thereby creating a greater degree of latitude for designers and safety engineers.

Production start-up in 2011 – and the market is expanding
One of the most advanced systems on the market, Continental’s new control unit has been well received by vehicle manufacturers. Evidence of this is the fact that two European manufacturers will already be introducing it into production in 2011. Negotiations for further orders are currently underway. Continental is thus the trend-setter in a rapidly growing market. Analysts reckon not only with an awesome increase in the number of LEDs – soon to surpass 800 – in cars but above all with mushrooming growth in front headlight deployment. Here analysts foresee an overall rise of 150% in the next three years.

Dr. Tran Quoc Khanh, professor at the Technische Universität Darmstadt and head of its lighting engineering department notes: “The advantages that light emitting diodes have over conventional headlights are in the area of service life. Whereas halogen bulbs have a life expectancy of about 1,000 hours and xenon-filled bulbs around 2,000 hours, LEDs are good for up to 10,000 hours.” On top of this is the efficiency aspect. “In vehicle light engineering, too, the high-output light emitting diode is of considerable significance in terms of energy efficiency and eco-friendliness. This is due to its extended service life, high luminous efficacy – which will rise to 150 lumens/watt in a few years – and good controllability.”

Tightly networked LED control electronics
Continental is one of the few suppliers on the market to fully integrate the lighting control unit into the vehicle's data flow system. The control unit communicates with the central vehicle electronics system via LIN and CAN and thus processes, for example, the information received on speed, steering angle, driver’s lighting demands and the readings from light and rain sensors. What is more, the electronics have a modular structure, allowing them to be easily varied for different applications in various vehicle classes.

Alongside intelligent electronics, Continental’s light control unit boasts a number of physical advantages. As compact as a pocket calculator, it combines up to four control systems. This frees up valuable space in the front end of the vehicle for the vehicle manufacturer. Unlike comparable controls, the Continental solution is not integrated into the lamp housing but is fastened on the outside as a separate component. This means that in the event that the headlight's protective glass cover is damaged, there is absolutely no problem reusing the control device. This impacts favorably on insurance classification and repair costs. Conversely, the electronics can be replaced without having to change the headlights as well. To top it all off, the system is designed in such a way as to withstand the grueling thermal conditions prevailing in the engine compartment. Low-cost lighting electronics from Continental are – much like engine management – extremely tough and virtually temperature-insensitive. Whereas in the past designing LED headlights had vehicle manufacturers finagling many of the technical details and “chilling out” the electronics, LEDs can now be allowed to rub shoulders with the engine.

The lighting functions of these initial LED-equipped main headlights mark just a start. For developers at Continental, the next step involves controlling so-called matrix headlights, by means of which an even more individualized design of the light cone is possible. Left- or right-turn instructions from the navigation system can then take the form of headlight-projected signals on the asphalt. Or the system can trigger spotlight detection of pedestrians on the shoulder of the road up ahead. Admittedly, such headlight systems will still be a few years in the making, but at least the groundwork for such features has already been laid in Continental’s new control device.

Parallel to these developments in the area of driving lights, LED technology is now also being put to expanded use in the passenger compartment. With more than twenty years of relevant volume production experience, Continental is the market leader in applying LED technology to vehicle instrumentation.