Helping You See
How advanced automobile lighting and optical technology help you see what’s ahead of you.
Drivers need all the help they can get when driving at night, and in poor driving conditions such as in fog and heavy rain. Learn how advances in lighting and imaging technology are helping drivers see farther, clearer and better. 1.
HALOGEN >> XENON >> LED A car’s headlamps are the most basic tool that it has to help you see in the dark and in poor conditions such as fog or heavy rain. Today, the most prevalent lightning technology is the halogen lamp, which is essentially a long-lasting, brighter version of the light bulb that Thomas Edison invented. It is widely used because of its compactness, simplicity and long lifespan - often up to a thousand hours.
Over two decades ago, BMW was the first automaker to make use of xenon or high-intensity discharge headlamps. Instead of a filament, these headlamps use two electrodes inside a tube that is filled with xenon gas, vaporized mercury and metal halides. A spark is created upon startup and the reaction inside creates a bright white light. Xenon headlamps are favored because of their longer lifespan, better efficiency and brightness. However, they are costly to implement and are so bright that they can sometimes blind oncoming traffic.
The latest in headlamp technology is LED lights, which was first used on a Lexus in 2008. They are favored by automakers because of their compact size and extremely low power consumption, even if they are not as bright as xenon headlamps. However, LED-based headlamps are costly to implement because they are sensitive to high operating temperatures and therefore require some kind of heatsink to help dissipate heat and operate reliably. Hence, they are often only in a limited scope such as for turn signals, brake lamps or daytime running lights.
ADAPTIVE HEADLAMPS Adaptive headlamps are technologies that dynamically adjust the car’s headlamps to improve visibility in poor driving conditions. One example of this are self-leveling headlamps that keep headlamps pointed on the road using sensors that can tell whether the car is tilted forward or back. This is useful in situations when a car drives over a large bump and causes the headlights to point upwards and into oncoming traffic.
A more advanced form of this technology can be found in BMW cars. Aptly called “Adaptive Headlights”, cars fitted with this system can cast their beams in the direction of the curve to provide better visibility when driving in the dark or in poor conditions on winding roads. This is achieved by using sensors that measure speed, steering angle and yaw. Audi has a similar system that uses GPS technology to predict and start illuminating turns and corners even before the driver turns the steering wheel. 3. NIGHT VISION AND OBSTACLE DETECTION One of the most recent innovations to car safety are night vision cameras, which help drivers see better at night, on poorly-lit roads or in adverse weather conditions. They can even be used to spot and highlight potential dangers and obstacles.
Such systems come in two forms and are either active or passive, using either infrared or thermographic cameras. Infrared cameras are considered active because they illuminate the road ahead with infrared light that is invisible to humans. On the other hand, thermographic cameras are considered passive because they capture thermal radiation that is emitted by objects. The captured footage is then displayed either on the instrument cluster or on the windscreen via a heads-up display. It can then send both visual and audio warning cues to the driver.
Compared to thermographic cameras, infrared cameras offer higher resolution images, but suffer from shorter range and do not work well in rain and fog. On the other hand, thermographic cameras can offer up to 50% greater range, enabling them to work effectively up to 300 meters. They are also especially effective at capturing living objects, since they emit a heat signature. On the flip side, since they rely on detecting heat signatures, they work poorly in places with warm climates. Additionally, the images they produce are often less sharp, and they require a large sensor which makes installation and implementing them into designs tricky.