As two widely used LED lens materials, PMMA (Polymethyl Methacrylate) and PC (Polycarbonate) exhibit significant differences in optical performance, mechanical strength, heat resistance, and environmental adaptability.

This is a practical comparison of PMMA led lens and PC led lens for LED designers & buyers. We will analyze in detail the advantages and disadvantages of PMMA and PC materials for manufacturing LED light lens.

For those who are not very familiar with LED lens, you can refer to our previous article introducing LED lenses: Custom LED Lenses Manufacturer: One-stop Service for Your Projects.

Based on our experience, customers who manufacture streetlights, led flood light with lens and other outdoor lighting fixtures generally prefer LED lenses made of PC material because of its high temperature resistance and good toughness.

Definitions of PMMA and PC

PMMA (Polymethyl Methacrylate), widely known as plexiglass or acrylic, is a transparent thermoplastic, characterized by achieving extremely high transparency. The "acrylic sheet" in our daily lives is the most common and prevalent commodity form of the material "PMMA".

PC (Polycarbonate) is a high-performance engineering plastic designed for strength, toughness, and thermal stability. It is often described as "as transparent as glass and as tough as steel". The plastic products we commonly use in our daily lives are generally made of PE (Polyethylene) or PP (Polypropylene).

From the broadest material classification perspective, PMMA (acrylic) and PC (polycarbonate) are both essentially "plastics," or more accurately, both belong to synthetic polymers.

One specializes in providing consistently high transparency and visual performance, while the other boasts unparalleled impact resistance, high heat resistance, and mechanical strength.

Comparison of PMMA and PC

1. Optical Clarity & Light Transmission

PMMA (Acrylic): It delivers superior optical clarity with a light transmittance of 92% or higher. This maximizes luminous efficacy and ensures minimal light loss, making it ideal for applications where achieving the highest possible light output and precise optical control are priorities.

Polycarbonate (PC): It has good clarity but slightly lower light transmittance, typically around 88-90%.

2. Weather Resistance & UV Stability

PMMA (Acrylic): It offers excellent inherent UV resistance. Its molecular structure provides long-term weather resistance, preventing yellowing and haze from sun exposure over many years. This ensures consistent light color and output.

Polycarbonate (PC): It is susceptible to UV degradation and will yellow and become brittle if unprotected. For outdoor applications, PC requires UV stabilizers or a protective hard coating. The long-term reliability of this coating is a maintenance consideration.

3. Mechanical, Thermal & Surface Properties

PMMA (Acrylic): This material offers good impact resistance and is shatter-proof, providing a significant safety advantage over glass. Its surface hardness is superior to that of PC, resulting in better inherent scratch and abrasion resistance, which is beneficial for long-term exposure to environmental elements like wind-blown sand. In terms of heat resistance, PMMA has a moderate continuous service temperature of approximately 80-90°C.

Polycarbonate (PC): PC is distinguished by its extremely high impact resistance. It exhibits excellent dimensional stability under mechanical stress and vibration. For thermal performance, PC provides superior heat resistance with a continuous use temperature of about 120-130°C, making it suitable for high-power LED systems.

For cleaning and maintenance, PMMA should not be cleaned with alcohol, and PC should not be cleaned with alkaline cleaners.

4. Processing & Cost Considerations

PMMA (Acrylic): It is highly injection moldable, allowing for complex optical designs for led lens, including customized led angle lens with precise light distribution and intricate surface structures.

Polycarbonate (PC): It has good processing performance, but adding a UV coating would further increase the cost.

Generally speaking, if PC LED lenses are not coated with UV stabilizers, the cost of the two will be about the same for standard led light lens. And if heat dissipation and waterproofing are handled properly, their lifespan is typically 5 years.

The table below presents a comparison of the two in various aspects comprehensively:

Another point to note is that, besides the significant differences in heat resistance and impact resistance, PMMA led lens are also slightly more brittle in terms of toughness.

This means that PMMA lenses are more prone to cracking when screwing in screws for waterproofing, while PC led lens, being more flexible, do not present this concern.

Application-Based Material Selection

Choose PMMA when:

Maximum light output and optical clarity are required

Long-term UV stability is important

The application is indoor or low-impact outdoor

Typical scenarios:

Indoor lighting, decorative lamps, displays and electronic equipment, automotive lighting, eyeglass lenses

Choose PC when:

Impact resistance and safety are critical

The environment involves vibration, shock, or mechanical stress

The LED system operates at higher temperatures

Long-term structural durability is required

Typical scenarios:

Outdoor lighting, automotive lighting, security equipment, industrial equipment, aerospace

FAQ

Q: Is PMMA cheaper than polycarbonate?

A: If the LED PC lens does not have a UV coating, the cost of the LED PMMA lens and the LED PC lens is roughly the same. Please consult our engineering team for specific pricing.

Q: How can you tell if a lens is polycarbonate or plastic?

A: There are two relatively simple methods:

1. Listen to the sound: Gently tap with your knuckles or a hard object. PMMA produces a crisper, louder sound, similar to a metallic tone. PC produces a relatively lower, more muffled sound.

2. Try bending (for sheets or thin plates): Try bending the led plastic lens slightly with your hand. PMMA feels harder and more brittle, with less elasticity, and feels like it's about to break. On the other hand, PC exhibits excellent toughness, feels more flexible and elastic, and can be bent into larger arcs.

Q: What is the main advantage of polycabonate lenses over regular glass lense?

A: The main advantage of polycarbonate (PC) lenses over ordinary glass lenses is their superior impact resistance. They are lighter, stronger, and less prone to breakage.

Conclusion

PMMA excels in optical performance and UV stability, while PC delivers superior mechanical strength and heat resistance.

Selecting the right led lens material is not about choosing the “best” option, but about choosing the most suitable material for the specific application, environment, and performance requirements. A well-matched led plastic lens material ensures higher efficiency, longer service life, and better overall value for LED lighting systems.

If you still have questions about which LED lens to choose, please feel free to contact us. Founded in 2009, Shenzhen Sunshineopto is a high-tech enterprise specializing in LED optical components. We focus on designing and manufacturing high-quality LED lenses and reflectors for a wide range of lighting projects.