Patent ID: 6447175
Filing Date: 2002-09-10
Classification: G03B,Y10T

Abstract:
A method of manufacturing a light shielding blade having a major surface portion capable of shielding an incident light and a roughened edge face portion perpendicularly crossing to the flat surface portion by using a base piece formed in a predetermined shape from a film material made of a polyester, the method comprising:punching said film material to form said base piece with a major surface portion and a smooth edge face portion; and a chemical etching step of applying a chemical etching to said smooth edge face portion of the punched base piece so as to roughen the edge face portion by forming a plurality of pores in said smooth edge face portion, thereby suppressing a reflection of said incident light at the edge face portion wherein said punching step is performed by punching said base piece in a predetermined shape from a film material, which is provisionally oriented bi-axially and which is made of a polyethylene terephthalate, and wherein said chemical etching step is performed by dipping said base piece for 5 to 20 minutes in an aqueous solution, which contains 20 to 50 wt % NaOH or KOH and which is heated to 80 to 90Â° C.