Uniaxially stretched multi-layer laminate film, polarizing plate comprising same, optical member for liquid crystal display device, and liquid crystal display device

Abstract

A uniaxially stretched multi-layer laminate film that exhibits a high polarization performance of 99.5% or more in a simpler configuration than before, a polarizing plate that is composed of the same, an optical member for a liquid crystal display device, and a liquid crystal display device are provided. Namely, in the uniaxially stretched multi-layer laminate film in which a first layer and a second layer are alternately laminated, the uniaxially stretched multi-layer laminate film includes an intermediate layer that has a thickness of 2 μm or more and 30 μm or less; the first layer is composed of a polyester containing a naphthalene dicarboxylic acid ester; the second layer is composed of a copolymer polyester and is an optically isotropic layer that has an average refractive index of 1.50 or more and 1.60 or less; the first layer, the second layer, both first and second layers, or the intermediate layer contains a visible light absorbent, which has a weight loss of less than 10% when it is kept at 300° C. for 1 hour, in an amount of 200 ppm or more and 2500 ppm or less on the basis of the weight of the layer; the uniaxially stretched multi-layer laminate film has a polarization degree of 99.5 or more; and the average transmittance Ts for S-polarized light in a wavelength range of 400 nm to 800 nm is 60% or more.