1. The definition and production of semi-finished lenses
Semi-finished lens is the raw blank used to produce the most individualized RX lens according to thepatient's prescription. Different prescription powers request for different semi-finished lens types or base curves.
The semi-finished lenses are produced in a casting process. Here, liquid monomers are first poured into moulds. Various substances are added to the monomers, e.g. initiators and UV absorbers. The initiator triggers a chemical reaction that leads to hardening or "curing" of the lens, while the UV absorber increases the UV absorption of the lenses and prevents yellowing.
2. Minus and plus semi-finished lenses
Lenses with different dioptric powers can be made from one semi-finished lens. The curvature of the front and back surfaces indicates whether the lens will have a plus or minus power.
Semi-finished lens is the raw blank used to produce the most individualized RX lens according to the patient's prescription. Different prescription powers request for different semi-finished lens types or base curves.
3. 1.499 CR39 UC:
Aogang CR-39 lenses use the true value of imported CR-39 monomer, the longest history of resin material and the most widely sold lens in middle level country. This determines that Aogang CR-39 lenses have the most outstanding optical features:
----Hardness: The best among other index lenses in hardness and toughness, high impact resistance.
----Tintable: The most easily tinted than other index lenses.
----Transmittance: The highest transmittance as compared with other index lenses.
----ABBE: The highest ABBE value providing the most comfortable visual experience.
----Consistency: The most reliable and consistent lens product physically and optically.