Patent ID: 7872803

Claim:
A lengthy grid polarizer film comprising: a transparent and lengthy resin film, of which a plurality of rows of grooves extending substantially in parallel with each other are formed on the surface; and a thin film made of a material G being 1.0 or more in the absolute value of the difference between the real part n 1 and the imaginary part κ 1 of the complex refractive index (N 1 =n 1 −iκ 1 ) thereof, and laminated on the bottom face of the grooves and/or on the top face of a ridges of ridges located between the adjacent grooves; in which a width t of the grooves of said resin film, an interval d between said adjacent grooves, the slope angle θ of the side wall of the grooves, the depth h 0 of the grooves, the film thickness h 1 of the thin film laminated on the bottom face and/or the top face, the complex refractive index N 0 (=n 0 −iκ 0 ) of the resin film for light at the wavelength in vacuum of λ 0 and the complex refractive index N 1 (=n 1 −iκ 1 ; n 1 ≧2.5 or κ 1 ≧1.5) of the material G for light at the wavelength in vacuum of λ 0 satisfy the relation of: −0.1δ<( h 0 −h 1 ); however, δ=λ 0 /(2π 2 n 1 2 κ 1 ) 1/2 (1) 60°≦θ≦90°; (2) when, z is the distance in the groove depth direction; θ(z) is the inclination angle between the side face and the direction perpendicular to the groove depth direction in the distance z; θ = 1 / h o ⁢ ∫ 0 h 0 ⁢ θ ⁡ ( z ) ⁢ ⁢ ⅆ z ( A ) d<λ 0 /n 0 , and (3) 0.1d<t<0.8d. (4)