With many new innovations in headlight technology – we wanted to share everything you need to know to make the informed decision when buying your next car. From LED to halogen lamps, day-time running lights and more.
In the early days, automotive engineers had to solve a basic problem – how to reliably generate light with limited resources (from a car). From the mid-19600s until now, tungsten filaments have been encased in halogen gas in order to improve the performance and longevity – the solution that they found all those years ago has been pretty consistent, until recently.
Traditionally, tungsten and halogen lamps focused light on the road via a lens that doubled as the headlights protective housing. This is now not the case – since the 1990s the exterior casings of headlights have been made from polycarbonate while light from the bulb is often aimed via a series of reflectors. Alternatively, the light beam is directed by a projector lens within the headlight housing.
While these low cost and long lasting bulbs are the most common headlamp type – the market is rapidly changing.
HID (High Intensity Discharge) headlights
HID headlights are a mixture of rare metals and gases that are heated to produce a bright white glow. HID headlights are two to three times brighter than their halogen counterparts. The Australian Design Rules require cars with HIDs to also have self-levelling mechanisms as well as headlight washers – this is due to the affect HID headlights can have on other road users.
HID lamps require less power to operate and are easy to distinguish as their cool white glow is often accompanied by a distinctive blue tinge. HID lights contain a trace amount of the gas xenon – and they are often commonly referred to as xenon headlights.
LED (Light Emitting Diodes) headlights
LED headlights have also come a long way, they hit maximum brightness within a millionth of a second, however, currently they fall short of the brightness achieved by HIDs.
The biggest selling point of LEDs are that they convert most of the energy created into light and not heat. Of late, LED headlights have started heading into mainstream cars – and as of late have become available on the Corolla sedan.
BMW was the first to offer Laser headlights as an option in its i8 plug-in hybrid supercar. Laser beams are focused towards a cloud of yellow phosphorous gas, the gas then emits a powerful white glow – which is then reflected and diffused to light up the road. BMW claims that these headlights can illuminate the road up to 600 meters ahead of the i8 – making them more efficient than other variants on the market.