An illumination unit capable of obtaining
high luminance and a display apparatus including it are provided. The illumination unit includes an illumination optical
system generating the illumination light, and a lens sheet narrowing a
divergence angle of the illumination light. The illumination optical
system includes a first transparent substrate and a second transparent substrate that are separated from each other and are arranged to face each other, and a
light source applying light to an end face of the first transparent substrate or of the second transparent substrate. The illumination optical
system is provided in a gap between the first transparent substrate and the second transparent substrate, and includes a
light modulation layer exhibiting scattering characteristics or transparent characteristics with respect to the light from the
light source in accordance with a magnitude of an
electric field. The illumination optical system includes an
electrode generating an
electric field that generates a plurality of linear scattering regions in the
light modulation layer in a three-dimensional display mode, and generating an electric filed that generates a planar scattering region in the
light modulation layer in a two-dimensional display mode.