1. Durability: Glass is highly resistant to scratches and abrasions, which is crucial for headlights that are constantly exposed to road debris, dust, and other abrasive particles. Plastic lenses, on the other hand, can easily become scratched or曇った from these elements, reducing their clarity and compromising visibility.
2. Heat Resistance: Headlights generate a significant amount of heat due to the high-intensity bulbs or LEDs they use. Glass can withstand high temperatures without melting or deforming, ensuring the headlights' functionality and safety. Plastic materials, while improving in heat resistance, still have a higher risk of melting or warping under extreme heat.
3. UV Resistance: Glass is naturally resistant to ultraviolet (UV) radiation from the sun. This resistance prevents the headlights from becoming黄変 or brittle over time, maintaining their clarity and performance. Plastic lenses, on the other hand, can be susceptible to UV degradation, leading to discoloration and reduced light output.
4. Repairability: Glass headlights can be easily repaired in the event of minor scratches or damage. Specialized repair kits and techniques can restore the clarity of the glass lens, extending the life of the headlight. Plastic lenses, while potentially more shatter-resistant, are generally not repairable and require replacement in case of significant damage.
5. Regulations and Standards: Many countries and regions have specific regulations and standards for car headlights, which include specifications for lens materials. Glass has historically been the preferred choice due to its compliance with these regulations and safety requirements.
However, it's worth noting that advancements in plastic technology have led to the development of high-quality, durable, and UV-resistant plastic lenses that are increasingly being used in modern cars. These plastic headlights often incorporate coatings and additives to enhance their scratch-resistance and overall performance.
