Everyone remembers driving down a dark road late at night when, suddenly, a car approaches going in the opposite direction. As it approaches, it seems as though their headlights are becoming brighter and brighter. Just before the car passes you, you decide they must have had their high-beams on. Why were their lights so bright?
Until recently, all cars on the road used what are called reflector headlamps. A reflector headlamp is just what it sounds like, the actual light comes from a bulb in the center of the headlamp housing and reflects off of the sides of the housing. This allows the light being emitted from the small bulb to be spread out on the road in front of the vehicle. While this allows the driver to see the road clearly at night, it also presents a hazard for oncoming vehicles. Engineers have attempted for years to design headlight that would illuminate the road while not blinding oncoming drivers.
About ten years ago, you might have noticed a different type of headlight housing starting to appear, called the projector headlight. Projector headlights also do exactly what they sound like-they project the light rather than reflecting it. This type of housing calls for a different type of light bulb to accommodate the housing. Projector headlights allow for more control of the light beams as they are emitted from the housing. One should not confuse projector headlights with HID headlights. While all HID’s come in a type of projector housing, not all projector headlight housings use HID bulbs.
Here is a comparison between the projector and reflector headlights. On the top, you can see what appears to be a small rounded bulb inside the projector housing. This is where the light is actually emitted. Because of the design of this “bulb”, the projector housing can control the trajectory of the light beams, providing for a more controlled lighting environment.
The Reflector Housing, shown on the bottom, simply takes the light emitted from the bulb and reflects it as much as it possibly can. Because of the shape of the reflective walls inside the housing, it lacks the ability to control the direction of the light, resulting in more scattered light.