|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Lenses |
|
|
|
|
|
|
History |
|
|
|
|
|
Plastic was first introduced to the optical lens
industry as a laminate of glass lenses with the Motex lens in the
1930’s. The Motex lens mimicked the technology used at that time on
car windshield. Glass laminated with thin sheets of plastic helped
prevent excessive splintering of glass in the event of an accident.
The laminated glass lens was short lived, but paved the way for the
Igard® lens, the first true plastic lens. This lens was introduced
by and English company named COIL (Combined Optical Industries
Limited) and was made of PMMA (Polymerized Methyl Methacrylate).
Besides the light weight factor, the Ingard® lens turned yellow,
scratched easily and were expensive. In 1947 Armolite introduced
CR-39 lenses. CR-39 is a material that was derived for the military
as durable light weight plastic used on military planes in WWII.
CR-39 plastic is actually ADC (Allyl Diglycol Carbonate), invented
by an Ohio based company named Columbia Southern Chemical Company (CSCC)
a subsidiary of Pittsburg Plate Glass Company (PPGC). CSCC initiated
a project named “Columbia Resins” and achieved its goal on the 39th
attempt, hence leading to CR-39. Sola,
Essilor,
Armolite, Univis Lens Co. and
3M (Minnesota
Mining and Manufacturing Company) are notable companies that
helped to pave the way for the CR-39 lens. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Specifications |
|
|
|
|
|
|
The CR-39 lens has an index of 1.498 and has an
Abbe Value of 58 with a specific
gravity of 1.32 g/cm3. |
|
|
|
|
|
|
|
|
|
|
|
Advantages |
|
|
|
|
|
|
- The most available lens considering lens
type and premium lenses.
- Almost 50% lighter than Glass
- One of the best and easiest mediums to
tint
|
|
|
|
|
|
|
|
|
|
|
|
Disadvantages |
|
|
|
|
|
|
- Low index of refraction (not ideal for
heavy + or - prescriptions)
- Not as scratch resistant as glass
|
|
|
|
|
|
|
|
|
|
|
|
|
555 N. St. College Blvd.
Suite #208 ● Anaheim, CA 92806 |
|
Bus: (714) 776-3335 ● Fax:
(714) 400-0127 |
|
Email: info@worldoptic.com |
|
|
|
worldoptic.com © 2001 All other Trademarks belong to their respective owners.
|
|
