Protective film for polarizing filter and method for producing thereof and polarizing filter
AssigneeFuji Photo Film Co., Ltd.
InventorsTakashi Ito, Hiroshi Nakashima
Life of this patent
Estimating the term…
Abstract
In a polarizing filter, first and second protective films are adhered to a polarized film. The first protective film has rigidity at less than 320 kPa·m and degree of curl at more than 10 mm. The second protective film is not curled and has rigidity at more than 320 kPa·m. The protective films are produced in a solution casting method in which a solution is cast on a substrate continuously fed. The solution is dried to form the protective film. When a remaining solvent in the protective film is less than 60%, then the protective film is peeled from the substrate.
Claims13
A protective film for a polarizing filter comprising:
- rigidity being less than 320 kPa·m;
- and degree of curl being more than 10 mm.
A polarizing filter comprising:
- a polarized film having a first surface and a second surface in a side opposite to said first surface;
- a first protective film having a rigidity less than 320 kPa·m and being curled with a degree of curl more than 10 mm so as to form a concave surface and a convex surface;
- and
- an adhesive agent applied to said concave surface of said first protective film, said adhesive agent adhering said protective film to said polarized film.
A method for producing a protective film from a solution for a polarizing filter, comprizing:
- feeding a substrate continuously;
- casting said solution on said substrate;
- drying said solution on said substrate by applying a hot air blow so as to form said protective film;
- peeling said protective film from said substrate when a remaining solvent of said solution is less than 60 %;
- drying said protective film such that said film may have a curl in a widthwise direction;
- and
- winding said protective film with said curl.
Dependencies are inferred from the claim text.