The history of automobile lighting

Before the use of electric lighting around 1920, the first generation of automobiles used candles, oil lamps and carbide lamps. From candle to LED lamp, a walk through the history of automotive lighting.

The candle and oil lamp

Candles and oil lamps were already used in homes at the beginning of the 19th century, but also on horse-drawn carriages and bicycles. It was only natural that from around 1890 these light sources were also used on the first automobiles. Both the candle lamp and the oil lamp, with the light visible at the front, rear and sides of the lamp, were mainly intended to make the vehicle visible to others. The headlamp, for better visibility of the road, appeared from 1900 onwards when the carbide lamp was introduced and speeds increased. It now became possible to drive in the evening on unlit roads. The photo below shows a candle lamp on the Panhard Levassor Phaeton from 1895, which can be viewed in the Louwman Museum.

The candle is placed in a tubular holder beneath the lamp. A coil spring under the candle keeps it in position in the lamp while it burns, until it is completely used up. Oil lamps were also widely used at that time; they are less sensitive to wind and give a bit more light than candles. The first Ford Model T from 1908 was fitted with oil lamps as tail lights and carbide lamps as headlights. The model did not receive electric lighting until 1915. The photo below shows the De Dion-Bouton Vis a Vis 3HP from 1899, fitted with copper oil lamps on the sides and a single elegant copper carbide lamp as the headlight at the front.

The carbide lamp

The carbide lamp, invented by Thomas Leopold Willson in 1892, was first used for, among other things, indoor lighting (where there was no electricity yet), in lighthouses as a beacon at sea, in coal mines and on bicycles. Its use on automobiles began around 1900. Carbide lamps produce their bright white light by burning acetylene gas, which is created by a chemical reaction of calcium carbide with water. In the carbide generator there is a lower chamber where the granular calcium carbide is placed and held in position by means of a lid and a spring (see drawing).

In the upper chamber there is a water reservoir. Using a control valve, the dripping of water onto the calcium carbide is regulated. Adjusting the amount of water drops determines the production of acetylene gas and thus also the size of the flame and the amount of light in the lamp. The acetylene gas flows through a gas line to the burner in the lamp unit. The lamp is lit using a match or a flint lighter. The gas generator and the lamp are often two separate units; however, there are also carbide lamps in which the gas generator and the lamp are housed in a single unit, such as on the Spyker 60-HP from 1903, on display in the Louwman Museum (see photo).

Carbide lamps give exceptionally bright white light and are therefore suitable as headlights. They are also insensitive to wind and rain. However, the lamps are expensive and also require regular maintenance, such as removing the ash after burning, regularly refilling with water, and adding calcium carbide.

The electric lighting

The first electric lamps, invented by Thomas Edison in 1879, had a number of disadvantages. The lamp consisted of a carbon filament placed in a vacuum glass bulb. The carbon filament had a lifespan of only 40 hours and the efficiency, the light output, was very limited. From 1920 onward the carbon filament was replaced by a tungsten filament and the lamp then had a lifespan of 1500 hours, while the light output was improved by about 10%.

The first electric rear light appeared in 1915, and from 1919 electric headlights became available to replace the carbide lamp. From 1920, dynamos for electric lighting on gasoline powered automobiles became commonplace. The electric headlights and rear light ornaments were initially mounted as separate units on the bodywork, just as was the case with the carbide headlamp and the oil lamps (see photo).

It was from the 1930s onward that headlights, taillights and turn signals were integrated into the body shape by bodywork designers. Sometimes there were exceptional designs, such as for the side turn signals on, for example, the Volkswagen Beetle (see photo) and the 1953 Ford Anglia.

When the turn signal was activated, an arrow shaped arm fitted with an electric light emerged from the center pillar to indicate that the driver was going to turn in that direction. This was a very clear signal for both oncoming and following traffic. Later, however, this construction was banned because the protruding arm could cause injury to people, and small side indicator lamps were installed in the front fenders instead. In practice this did not turn out to be an ideal location, because from 2010 onward the side indicators on new cars were moved en masse from the front fenders to the left and right exterior mirrors. This was possible because the law required exterior mirrors to fold in on impact to prevent injuries. In the end, we returned to a design where the turn signal sticks out from the bodywork, as on the Volkswagen Beetle and other models from the 1950s!

Just like carbide lamps, the first electric headlights had the drawback of dazzling oncoming drivers. This was partly solved by using a parabolic reflector and a lens. In 1924 this was improved by the invention of the Bilux or Duplo bulb with two filaments, one for low beam and the other for high beam. The filament for the low beam is half shielded and produces a light beam aimed at the road surface over a distance of about 80 meters. Oncoming traffic is not disturbed by this light. The filament for the high beam illuminates the entire road surface and the surroundings over a distance of about 150 meters in front of the car, but in this case oncoming traffic is bothered by glare. For this reason it is not allowed to use high beam when oncoming traffic is approaching. Street lighting on roads makes it possible to drive using only low beam. On unlit roads, however, high beam is often indispensable, and manually switching to low beam for oncoming traffic is still an action that is often forgotten. Automatic switching from high beam to low beam and vice versa has already been developed, but is not widely used in production. By contrast, the automatic anti-glare interior mirror has already become commonplace.

From Sealed Beam to Halogen

In 1940, the round sealed beam headlamp was introduced in America in order to create a standard headlamp that was the same for all passenger cars. The lamp with lens, reflector and filament was housed in a single sealed unit and had a standard size. In America, this standard headlamp unit was made mandatory by law.

From 1960 onward this standard headlamp unit was adopted by almost all car manufacturers in Europe and Japan. However, with the arrival of the replaceable halogen bulb in Europe in the 1970s, this changed quickly. The Duplo replaceable H4 halogen bulb, with two filaments for low beam and high beam, was very popular in Europe because of its longer service life and higher light output compared to the traditional incandescent bulb (see photo H4 halogen bulb).

Moreover, from a styling point of view, car and lamp manufacturers in Europe preferred a headlamp design with an aerodynamic shape integrated into the car body. This concept was banned in America mainly because of the complexity of approving many different headlamp designs. This led to different front-end designs of cars in America and Europe, such as the use of pop-up headlights on cars for the American market. Ultimately, starting in 1983, America also completely switched from the sealed beam headlamp to the European aerodynamic headlamp unit with a replaceable halogen bulb.

The LED lighting

The technology of the LED (Light Emitting Diode) lamp was invented in the early 1960s. The first LED lamps in automobile production were used from 1993 onward, initially only for the taillights and the third brake light. It was from 2004 that LED was introduced as a headlamp and daytime running lamp (Daytime Running Lamp).

The modern LED lamps guarantee a longer service life (> 50,000 hours) and better light output (> 300 lumens per watt) compared to traditional incandescent and halogen lamps. They are also insensitive to shocks and the costs are relatively low. In addition, LED lighting has the special advantage of having virtually no warm up time. This is a significant safety benefit. A traditional incandescent bulb needs 0.3 seconds to light up, while with LED lighting this happens in less than a microsecond. During an emergency stop on the highway at a speed of 100 km/h, you therefore see the vehicle in front of you with LED brake lights 0.3 seconds earlier, which gives a gain of about 10 meters in braking distance! It is also for this reason that LED lighting was made mandatory for the (third) brake light.

Lighting for safety

Gradually, more and more legislation was introduced on lighting and signaling with the aim of increasing safety. This concerns both seeing better and being better seen. The light intensity, the color of the light, and the size and position of the various lighting elements on the vehicle were laid down in law to create uniformity. Many suggestions for improvements also came from automobile manufacturers and the lighting industry, such as the automatic switching off of the direction indicators when the steering wheel is straightened and the swiveling of the headlights while cornering.

Headlight level adjustment was also introduced and later made mandatory. When the car is loaded with luggage and extra passengers, it tilts backwards and the oncoming traffic is dazzled by the dipped beam. The first car with a self leveling headlight system was the Panhard Dyna Z from 1954. In the seventies, a manual dashboard control was developed for the driver, allowing the headlight level to be adjusted electrically depending on the load. Eventually, systems with fully automatic headlight level adjustment were also introduced.

Researchers are continuously working on improving automotive lighting. This article does not discuss all light sources used in cars, such as Xenon and laser lighting and intelligent systems that adjust the light to driving and weather conditions. What is certain is that there is a constant search for light sources that provide us with better, more energy efficient and safer light in the darkness.