Polycarbonate
From OpenOptix
The same material used for bullet-proof glass, polycarbonate is the most impact resistant of lens materials. Safety considerations and low cost make polycarbonate well suited for safety and children’s eyewear. With an index of refraction of 1.59, polycarbonate also produces thinner, lighter lenses than glass or plastic. These factors along with inherent UV protection make polycarbonate a popular lens material.
Material Properties
- Index of refraction: 1.59
- Specific Gravity (g/cm3): 1.21
- Abbe Value: 29
- Reflectance: 5.2
- Transmittance UVA (286 - 320 nm): 0.0
- Transmittance UVB (320 - 380 nm): 0.0
Pros
- Thinner and lighter than glass and plastic
- Highly impact resistant (used for safety glasses)
- Inherent UV protection
Cons
- Low Abbe Value
- Susceptible to distortion induced by manufacturing process
- Susceptible to scratching (correctable by coating)
- Susceptible to stress fractures in drill mounts
- Does not readily accept tint