US Patent 8045094 Backlight device, display device, and television receiver

A backlight device capable of preventing or reducing, even when an optical sheet bends, occurrence of luminance nonuniformity and/or shades due to the bend. The backlight device 1 controls the properties of light emitted by a light source 12 using two upper and lower diffusion sheets 16, 20 and a lens sheet 18 placed between the diffusion sheets and illuminates the back side of a display panel with the light, in which a space 24 for expansion is provided between the lens sheet 18 and the upper diffusion sheet 20, the space for expansion accommodating a bend of the lens sheet 18 which is caused by expansion due to heat from the light source 12.