Technology of Plastic lenses is moving forward. Plastic Lenses, High-Tech Lenses for the Digital Age. Plastic CR-39 Lenses from FramesDirect.com Most people refer to this lens type as "Regular" or "Plastic" Lenses. The patent of CR-39 allyl diglycol carbonate monomer in 1945 marked a key milestone in the history of the optical industry.
This new optical monomer inspired a great deal of creativity and ingenuity, which led to many of the great plastic lens products available today.
Plastic lenses made from CR-39 allyl diglycol carbonate monomer combine the optics of glass with the excellent mechanical, thermal and chemical resistance properties of a thermoset material. CR-39 monomer is used for casting plastic lenses for prescription eyewear, sunglasses and other plastic products requiring high abrasion resistance and high quality optical properties. Plastic lenses from CR-39 monomer give less chromatic aberration compared to polycarbonate lenses, as measured by the Abbe number.
The lens is light weight compared to glass, and may be made in just about any prescription, though many people with higher prescriptions prefer to use Hi-Index Lenses . The higher the index, the thinner the lenses. Plastic lenses are great for prescription sunglasses due to their tintability factor and you can virtually tint a plastic lens to any color under the rainbow.
CR-39 is a trademark of PPG Industries, Inc.
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