Patent ID: 7573549

Claim:
An optical device for a liquid crystal display apparatus that displays an image, the optical device being arranged at a front side of the liquid crystal display apparatus, comprising: a plastic-based film; and a diffusing layer formed at least one surface of the plastic-based film and scatters light that passes through the diffusing layer, the diffusing layer including: a medium; and inner scattering elements that selectively Mie-scatter visible light having a wavelength range of 400 nm to 500 nm into the medium, the inner scattering elements having a refraction index different from a refraction index of the medium, wherein the diffusing layer has pencil hardness of equal to or more than 2H under a 500 g-load specified in ISO/DIS 15184, and wherein, when the optical device is arranged at the front side of the liquid crystal display apparatus that displays color near eight test colors specified in CIE 1974, as a test color, the optical device being formed so that chrominance Δu′v′ obtained according to the following Equation 1 is equal to or less than 0.05, based on a chromaticity coordinate (u 0 ′, v 0 ′) of CIE1976UCS observed in the front side and a chromaticity coordinate (u′, v′) of CIE1976UCS observed at an observation angle of ±60 degrees in horizontal and vertical directions of a screen of the liquid crystal display apparatus when a direction perpendicular to the screen is assumed to be 0 degrees Δ u′v ′={( u′−u 0 ′) 2 +( v′−v 0 ′) 2 } 0.5 [Equation 1].