What are the major differences between PMMA and pc materials for optics and lens of automotive led lights

For all of the led work lights or LED strobe warning lights, optics or lens is one of the most important components to achive excellent lighting performance.

Basically, there are two types of materials for choice although they have some differences, one PMMA (polymethyl methacrylate),the other is PC (polycarbonate), which make them suitable for different applications.

Let us check the following distinctions between them.

1) Light transmittance:

PMMA can achieve a higher light transmittance, around 92% or even higher for specific grades. This makes it ideal for applications where light clarity is the most important, like high power led driving light or led work lamps with 4D optical len.


PC offers a slightly lower light transmittance, typically around 88-89%. While still good for some harsh applications, it might not be the best choice for situations requiring the longest lighting passage.

2)Impact resistance:

PMMA is made of more brittle material. It can scratch relatively easily and has lower impact resistance. This makes it less suitable for applications where lenses might experience shocks or impacts.

PC is famous for its high impact strength. Its much tougher than PMMA and can withstand significant impacts without breaking. This makes it ideal for hardened glasses, and applications prone to physical stress.

3)Temperature resistance:

PMMA endures a lower heat tolerance, typically around 70°C (158°F). At higher temperatures, it can soften and lose its shape.

PC can achieve superior heat resistance, reaching up to 120°C (248°F) or even higher depending on the specific grade. This wider temperature tolerance makes it suitable for applications exposed to heat.

4)Weather resistance:

PMMA can work under excellent weather resistance. It can withstand prolonged exposure to sunlight, rain, and wind without significant degradation.

PC requires UV protection for offroad use. While inherently good, PC can become brittle over time if exposed to UV radiation without proper additives. 
Manufacturers often adopt UV processing onto PC for outdoor applications.

5) Cost: Basically, PMMA is less expensive than PC.
 PC typically carries a slightly higher price cost due to its enhanced impact resistance and heat tolerance.

6) Refractive index: PMMA has a slightly higher refractive index than PC, which can influence light bending and potentially affect image quality in certain applications.

7) Scratch resistance: PMMA offers better scratch resistance than PC. However, with proper coatings, both materials can achieve good scratch resistance.

The best choice between PMMA and PC depends on the specific requirements of application.  For most of our automotive led lights, we adopt PC materials for optics, and we might choose PMMA for the 4D or projetor lens for led light bars and laser pod lights. We will consider all of the factors and choose the best cost-effective materials solution for our led lamps.