Lasers, projectors, LEDs. No, this isn’t some party planner's material list, but the headlight technology that has been advancing at a rapid rate and is finding place on our cars. And, it's getting more and more difficult to cut through the jargon; LEDs, halogens, projectors, xenons. So, what do they mean?
What are halogens?
A halogen bulb is similar to an electric bulb found in any household. But while your regular bulb has a filament (small wire) that heats up and emits light, the halogen lamp uses halogen gas to increase brightness.
These bulbs aren’t very efficient, as most of the energy is wasted in heat instead of light. Halogen bulbs used in automobiles typically emit a yellowish light and despite the technology being over 50 years old, it is widely used. In terms of brightness, halogen lamps have a throw of about 100 metres.
What are xenon headlights?
Also referred to as HID (high-intensity discharge), xenon lamps are similar to the ubiquitous tube light. There is no filament that gets heated up, instead, xenon gas is electrically charged. This produces a bluish-white light that is close in colour to natural light. Xenon lamps are more expensive than halogen but they generally last longer and are more efficient. As seen with tube lights, these lamps too have a small delay before lighting up and take some time to come to full brightness, which is why the high and passing beams generally get an additional halogen bulb. Thus, a car will have two bulbs in each lamp unit making it a total of four.
What are bi-xenon headlights?
The term bi-xenon headlight is a bit confusing, as ‘bi’ suggest two. But a bi-xenon uses just one xenon lamp for the high beam, which is then either moved or shaded each time a low beam is to be provided. Thus, a bi-xenon lamp is sometimes cheaper and also takes up less space in the lamp unit.
What is a projector lens?
Do not confuse these with projector lens lights; these do not necessarily indicate xenon bulbs. A projector is a simple lens which is used to focus the light source on to the road. It is quite similar to a movie projector you might have in your office or home. As you may have guessed, a projector lens can be used with any light source: halogen, xenon or an LED lamp.
