The development trend of headlights

The widespread use of PC masks and BMC reflectors has added new features to the headlights, allowing for the combination of various scattered single function lamps. Modern headlights include high beam headlights, low beam headlights, fog lights, front turn signals, front position lights, etc; But it also does not include fog lights or turn signals, which depends on the shape of the entire vehicle. Technically speaking, the lights installed in the front of a car can be combined together. The development trend of headlights can be seen from the following aspects.

exterior

With the widespread application of new technologies, materials, and computer-aided design, the shape of lighting fixtures becomes more casual while meeting regulations; The styling designer of the entire vehicle can have greater freedom. Previously, the shape of the headlights was either circular or square, and in most cases, each lamp only had one function. Since the application of PC face masks to front lights, there have been various changes in the front lights. Nowadays, the produced front lights have almost no square or circular shape, and are almost all opposite sex front lights that conform to the overall shape. In the past, some car companies used invisible headlights to reduce air resistance and achieve appearance effects, such as Porsche sports cars; But with the application of new materials and technologies, invisible headlights have become outdated products. The front lights of modern cars can fully conform to the overall shape of the car, have the same streamline, greatly enhance the overall appearance of the vehicle, and even become a personalized symbol of car manufacturers. They are a bright decoration on the car and an important symbol to distinguish different car shapes.

brightness

The main function of the headlights is to illuminate the road surface, prevent glare from others, and ensure driving safety. There are different methods to improve brightness and expand lighting range:

One is to improve the luminous efficiency of the light source. From incandescent bulbs in 1913 to gas discharge bulbs in the 1990s, the luminous intensity ranged from 15-18lm/W for incandescent lamps to 22-25lm/W for halogen lamps to 80-91lm/W for gas discharge lamps; There has been significant development. (Note: Increasing the power of the light bulb is not the solution to brightness. While a 100W light bulb is brighter than a 55W standard light bulb, it will generate a large amount of heat and may damage the reflector and other lighting components. At the same time, due to its consumption of much more electrical power than the standard light bulb, there is a risk of the vehicle's insurance and cables being burned and causing a fire. All guarantees from the lighting and vehicle manufacturers are completely invalid.). Therefore, it is prohibited to use 100W or more light bulbs on highways; This type of light bulb is only used during racing events With the increasing maturity of production technology, the decrease in prices, and the reduction in the volume of boost systems, gas discharge lamps have gradually been applied in small and medium-sized cars. In the future, it will be widely used in various types of vehicles such as sedans, heavy-duty vehicles, and buses. HID is a direction for the development of automotive light sources.

In addition, with the continuous development of technology and the continuous improvement of high emissivity white LEDs, LED will also be another direction for the development of automotive headlight light sources.

The second approach is to improve the utilization of light sources. At present, the utilization rate of parabolic mirrors is less than 30%, that of free-form mirrors is about 45%, and that of lens groups is about 50%. In the light loss of the reflector, 30-45% of the light does not shine on the reflector, and another 15-25% of the light is blocked; About 20% of the light in the lens group is also blocked. Car manufacturers in various countries have put a lot of effort into researching ways to reduce light loss. In the reflector type headlights, some Japanese lamp manufacturers make the light shield into a reflective type, reflecting back the light that could not have been shining on the reflector and the blocked light onto the reflector; German factories are fully leveraging their design advantages on freeform surfaces and gradually eliminating light shields to improve the utilization of light. In the lens type headlights, Japan uses multiple lenses, while Germany increases the lens diameter; Both methods have the same goal of increasing the area through which light passes.

The third type is in terms of functionality. In the coming years, the functionality of headlights will develop towards multifunctionality and intelligence. A multifunctional headlight recently developed by a German company breaks through the traditional division of low beam and high beam headlights, dividing the lights into urban lighting, rural lighting (including turning lighting), highway lighting, high brightness lighting, and daytime driving lighting according to different purposes.

The street lighting conditions in urban streets are relatively good, with low vehicle speeds and a large number of vehicles and people on both sides of the road. The requirements for front lighting are anti glare, large width, short distance, and high light intensity in the area, making it easy for drivers to observe the situation on both sides and in front of the vehicle.

Rural lighting is used in small towns or streets with poor lighting conditions, and its light distribution is similar to that of low beam headlights under normal circumstances. Due to the poor lighting conditions of the road, as well as the presence of bends and intersections, there is a turning lighting function. When turning, the light area will be illuminated in advance to the direction of the intended turn, and there is a distinction between left and right driving.

Highway lighting is used on highways. Due to the absence of pedestrians on the highway, all lanes are one-way and there is no problem of dazzling the other party. The light distribution is similar to that of high beams under normal circumstances, but its illumination distance is generally within 150m, because the driving speed of highways is usually between 100-150km/h; According to European regulations, the distance between vehicles at this time should be between 100-150m; In order to avoid discomfort to the driver in front of the vehicle, the illumination distance is generally within 150m.

The highlight lighting state projects all the light onto the road surface, fully utilizing the efficiency of the light source. Mainly used for outdoor driving without lighting and with very few vehicles.

Daytime driving lighting is a form of headlight developed based on the latest regulations in Europe, used for daytime driving without any lighting requirements.

The foundation of intelligent headlights is multifunctional headlights, with additional control systems, cleaning systems, near-infrared detection systems, etc. It can adjust the working status of the entire lamp based on various sensors detecting road conditions, weather conditions, and the status of the lamp (such as vehicle speed, load, etc.), clean the lamp in a timely manner, and maintain the best lighting effect. The use of passive near-infrared detection systems completely solves the problem of road detection at night and in harsh weather conditions, ensuring driving safety.

If it is a headlight, designing one ventilation hole is not enough. We must design two or more ventilation holes, and to prevent the phenomenon of excessive ventilation, the position of the ventilation holes cannot be placed in the same plane position.

The structure of the ventilation hole needs to be designed in the form of a maze to achieve the goal of "ventilation without water". Generally, we use black rubber to make the ventilation pipe into a curved shape.

If you want to do better, you can install a filter device at the bend to prevent air from flowing back into the lamp and bringing dust to the lamp in the event of a sudden decrease in temperature and back pressure, achieving the goal of dust prevention.