Show Me the Light
08 Jun 2016
Automobiles have been around for over 100 years and during that time they have evolved in ways that would have been incomprehensible in the years before. In particular, of all the technologies that automobiles have used over the years, perhaps none has changed more than the lowly headlight. Throwing light in front of an automobile has evolved from the dim flickering of gas in a lantern to the ultra-bright LEDs of today. Join us while we look at how the automotive headlight evolved over the last 100 or so years.
Starting in the late 1800s, headlight technology was simply a gas lantern with a reflecting mirror inside. The gas was usually acetylene and was made by adding water to calcium carbide. These lantern-based lights would burn for several hours but provided relatively low-candlepower. If a vehicle was moving slowly, they were an acceptable method of illumination, however, automotive engineers knew that more powerful lighting would be needed.
The first electric headlights debuted on an electrically-powered car, a 1898 Columbia. Unfortunately, they weren’t immediately much of an improvement. These early electric headlights had weak tungsten filaments that often broke on rough roads and they weren’t terribly bright to begin with. In fact, it was common for motorists to carry a number of replacement spares and be ready at all times to stop the vehicle to install another bulb.
Another issue with the early electric lights was that they cast a wide beam of light and focusing them into a more useful, brighter cone required bulky, convex lenses. In the early 1910s, the Corning Glass Company helped out when they debuted their Conaphore headlight which used a Fresnel glass lens to focus the light beam. Fresnel lenses allowed the glass covers to be far thinner than standard convex lenses which was tremendous advantage.
In the 1940s, the “Sealed Beam” was introduced. Anyone who’s worked on an American-made car from 1940 until the early 1990s knows what “Sealed Beam” headlights are. They are one-piece electric headlights combining the filament, reflector, housing, and lens all into one unit. They were made in standardized sizes which restricted the designs of automotive fronts to some degree.
Ultra-bright halogen bulbs debuted in the 1990s. Many people think that halogen is a type of gas. Halogen is not a gas, it’s actually a group of special chemicals combined with an inert filler gas. It provides a special atmosphere that allows tungsten elements to burn brighter and with less energy. May cars use halogen bulbs today.
The sales staff at Sandoval in Columbus, OH, a full-service Buick, GMC dealer, tells us the cutting edge now in automotive headlights is light-emitting diodes (LEDS). They are solid state devices (no filaments) and are ultra-bright. LEDS have been used on parking lights, taillights, and turn signals for several years now and they are starting to be put into headlight applications. One of the most important advantages that LEDS offer is that they are low-heat producing and are thus very efficient.