Patent attributes
An illuminating device includes: a light source; a light guide plate which converts light emitted from the light source into a surface light ray and emits the surface light ray through a front surface of the light guide plate; and an optical sheet which changes a propagation direction of the surface light ray emitted from the light guide plate. The light source is arranged in opposition to one end surface of the light guide plate. A polarization state converting structure to convert a polarization state of the light propagating through the light guide plate is provided in a rear surface of the light guide plate. The polarization state converting structure contains an inclination plane having a ridge line extending in a direction perpendicular to the extension direction of the one end surface.
