LIGHT DIFFUSION FILM,SURFACE ILLUMINANT DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

A transmitting display device(21)comprises a liquid crystal display unit(22)and a surface illuminant unit(23).The surface illuminant unit comprises a tubular light source(24),a light guide member(25)having a wedge−shaped reflection groove formed at the lower portion thereof,and a light diffusion film(27)having anisotropic and/or ultraviolet absorbing properties.The light diffusion film satisfies Fy(θ)/Fx(θ)≥1.01 within a range of scattering angleθ= 4−30°,where Fx(θ)is a scattering characteristic in the X−axis direction of the film,and Fy(θ)a scattering characteristic in the Y−axis direction when a scattering characteristic F(θ)gives the relation between a scattering angleθand a scattering light intensity F.The light diffusion film comprises a light diffusion layer comprised of a plurality of resins having mutually different refractive indexes,and a transparent layer laminated on at least on surface of the light diffusion layer.At least the transparent layer may contain a ultraviolet absorbing agent.Such a light diffusion film,when used,can simplify the structures of a surface illuminant device and a liquid crystal display device,and can make uniform the luminance of the display surface when the light diffusion film has an anisotropy.A light diffusion film having a ultraviolet absorbing property can absorb a ultraviolet ray from the light source(fluorescent lamp)of a surface illuminant device(back−light),and prevent the deterioration of a prism sheet and a liquid crystal display cell.