Plastic Optics

Acrylic is known for its very good clarity and excellent transmission properties throughout the visible portion of the spectrum. This material is very hard and has very good mechanical stability. It has an index @588nm of 1.49, and an Abbe number of 55.3. A acrylic lens, when paired with an appropriate styrene lens offers an effective achromatic solution.

Polystyrene is generally less expensive than acrylic. It has a higher index @588nm of 1.59 and lower Abbe number (30.87) than acrylic. The material also tends to absorb somewhat in the deep blue spectrum. Polystyrene has a lower resistance to UV than acrylic and is more easily scratched than acrylic.

Polycarbonate is similar to polystyrene in index (@588nm, 1.586) and Abbe number (29.9). It is known for its very high impact resistance and for the ability to perform over a wide range of temperatures (-137 to +124 C). Because of its high ductility, polycarbonate is not easily machine than acrylic.