Patent ID: 7022396

Claim:
A biaxially oriented film comprising; at least two layers including a film layer A of a polymer alloy composed of at least one of polyethylene terephthalate or poly(ethylene-2,6-naphthalenedicarboxylate) (polymer 1) and a polyetherimide (polymer 2) as essential components, and a base layer B; said film layer A being laminated as an outermost layer to the base layer B; wherein a content W A (% by weight) of the Polymer 2 of the film layer A and a content W B (% by weight) of the polymer 2 of the base layer B satisfy the following relations: 0≦W B ≦40 5≦W A ≦50 10≦W A −W B ≦40; and wherein micro protrusions having a height of 2 to 50 nm are formed at a density of 1,000,000 to 90,000,000/mm 2 on an outer surface of the film layer A.