They were dark times back in the 1920s, in a lot of different ways. Especially car drivers faced one new invention after the next, and non-drivers found themselves confronted with ever fuller roads. Traffic started rolling, and little by little everyone understood that carbide lamps were no longer up-to-date and even the new electrical lamps were no longer sufficient. More traffic and higher speeds of the now quite comfortable “horseless carriages” presented both the automobile industry and suppliers with completely new challenges. All of a sudden, even at night cars were constantly approaching, requiring the light to be dipped. Either mechanically or with several lamps which had to be switched on and off. Quite cumbersome.
In 1925, Osram showcased the world a simple, yet ingenious solution – a lamp with two filaments, one for dipped beam and one for high beam. This enabled all the functions, which previously took up a lot of space and required complex mechanical designs, to be combined in one single light source. The BILUX® lamp was born.
The lamp produced two beams with different strengths and angles in one single reflector. From 1956 on, asymmetrical light distribution, in which the passenger side of the road is illuminated brighter than the center of the road, was then ready for series production.
Although the brand name was specifically registered to Osram, it swiftly established itself as a general name for dual-filament lamps. Headlight manufacturers reacted quickly, and the Bilux lamp became the typical light in all conventional vehicles in the 60s and even the 70s. It’s still available today in its original form.
The Mercedes 540 K was the first standard production sedan featuring Bilux lights ex works. You can recognize these headlights by their convex diffusers; they dominate the old and modern classics scene in their many shapes, although halogen lamps overtook them little by little in the 60s. They also have two filaments and are “Bilux” but that’s a different story. The first generation of Bilux lamps generally has a P45t base and an electrical output of 40/45 watts. That’s a bit poor by today’s standards, especially if the reflectors are no longer entirely clear after many years. But compared with the first electrical lamps from previous decades, the “new” Bilux lamps shone brighter than a supernova during a pitch-black night.
That was good and sorely needed. Increasing traffic during these years and growing speeds made many changes to road traffic necessary. Finally, cars were not just seen but drivers could also illuminate the road at night so far ahead that they could make out obstacles in good time. So the Bilux lamp brought proverbial light into the darkness. The design of the headlights shaped whole generations of vehicles, with many upgrade kits available today also allowing other brighter types of lamps to be installed in the existing bases. Because traffic has once again dramatically changed since the 50s, and with it the headlights in our cars.