Headlight Evolution

In 1885, the German engineer Karl. Karl Benz developed the world's first three-wheeled internal combustion engine powered by a gasoline engine, but it was made of metal materials, and the car was born and developed rapidly. But to drive at night or on dark roads, you must have lighting tools, it can be said that with the car there are lights, lights and cars are born at the same time and synchronous development. The evolution of headlights generally goes through the following stages:
1. The first headlights were kerosene lamps installed in automobiles. However, the luminous intensity of the kerosene lamp is too low to meet the requirements of illuminating the long road in front of the car. In order to improve the illumination of the road ahead, the parabolic reflector with a plate invented by Krupin in 1779 (the prototype of the reflector) was used. The lamp with the Krupin reflector became the world's first spotlight, known at the time as the strong light, which could increase the intensity of the light placed on the focus of the mirror by 500 times. At that time, such a mirror was used to reflect the luminous flux of two light sources installed in front of the car light source, and concentrated in a narrow solid Angle to form a high-intensity beam. In addition to the headlights, it was also stipulated that the car must be equipped with a red window toward the rear - the prototype of the signal light. Later, there was a license plate lamp with acetylene as a light source, and because the supply of acetylene to the license plate lamp with a rubber tube was unreliable and dangerous, it was also necessary to use a kerosene lamp as the rear light of the car.
After the advent of incandescent electric light in 1879, it was natural to think of applying it to automobiles, but the initial attempt failed. Because the filament of the vacuum incandescent bulb at that time was made of carbon wire, it was very brittle and could not withstand the vibration of the car, especially its outline brightness was not high enough, only about 4*10000cd/m (cd -- Candela, light intensity unit), and the illumination of 1LX (1L -- Lux, illuminance unit) was generated at the beginning of 100M in front of the car. At least 32*10000cd/m is required. By 1905, acetylene was used as a light source for car lights. This is because the outline brightness of acetylene and other fires is about 7.2*10000cd/m, which is almost twice as bright as the brightness of the lamp at that time. Acetylene is produced by a chemical reaction between calcium carbide and water using a portable acetylene generator mounted on a car's foot pedal or frame. When driving, the turbulence or shaking of the car body just becomes the "catalyst" of this chemical reaction, and once the car stops, the reaction becomes weaker and the lighting becomes less and less. At that time, there were other high light sources, although they were also tried on cars, but they were not successful for various reasons, and finally only acetylene lamps became the stable light source of early lights, and has been used until around 1925.
3. In 1913, the electric light source was invented with spiral tungsten wire as the luminous body of the gas-filled (inert gas) incandescent bulb, so that the luminous efficiency from the carbon filament incandescent bulb 1lm/W to 15lm - 18lm/W. In the United States, it was used in the headlights of Cadillac cars and thus began the era of automotive electrical lighting. 1017 Cadillac's headlights began to use reflective tiles (the first headlight reflectors) to improve light energy utilization and increase illumination. However, acetylene headlamps still continued to be used for a long time, only gradually replaced by electric headlamps. The reason for this is that at that time, the engine cylinder gas ignition used a high-voltage magneto that was itself an independent power source, and the generator used a hand crank to start. The car has neither a generator nor a battery.
In 1912, the electric starter was invented to start the generator, which requires that the battery must be installed, and the tributary generator must be installed to charge the battery, which provides the necessary conditions for the electric light source lighting for the car, and is also an inevitable development trend. However, automotive electrical equipment (starters, generators, batteries, and electrical lighting equipment) was not available in every car at that time, but was an optional device installed separately according to user requirements. All cars are manufactured with electrical lighting, in fact from 1925, since then the electrical equipment system has become a necessity for every car. Car lamps are a green electric light source.