The waterproof performance of car headlights is achieved in the following ways:

1. Sealing design: The shell and lampshade of car headlights usually adopt sealing design to ensure that the interior of lamps is not invaded by external water vapor and moisture. The sealing design can use rubber sealing ring, silicone sealant and other materials to effectively seal all interfaces and joints of lamps and lanterns to prevent moisture from entering.

2. Waterproof materials: The choice of materials in car headlights also plays an important role in waterproof performance. The shell and lampshade of lamps are usually made of plastic or glass materials with good water resistance to ensure that the normal use of lamps will not be affected by moisture.

3. Waterproof treatment: In the production process, car headlights usually carries out waterproof treatment, such as coating waterproof coating or sealing the interface with waterproof glue. These waterproof treatments can effectively prevent moisture from infiltrating into the interior of the lamp and protect the circuit and bulb of the lamp from being damaged.

4. Waterproof test: After the production is completed, car headlights usually carries out waterproof performance test to ensure that it meets the waterproof requirements. The test methods include immersion test and water spray test to test the waterproof performance of lamps under different water pressure and water flow conditions to ensure that they can work normally in bad weather conditions such as rain and snow.

To sum up, the waterproof performance of car headlights is achieved by sealing design, waterproof materials, waterproof treatment and waterproof testing. Only by strictly controlling every link in the production process and ensuring that the lamps have good waterproof performance can car headlights work normally in various bad weather conditions and improve driving safety and comfort.