Backlight unit and liquid crystal display device

Abstract

The backlight unit includes: a light guide that includes an incidence surface and an emission surface facing each other; and a light source portion including a plurality of point light sources that are two-dimensionally arranged to face the incidence surface of the light guide, in which light emitted from the light source portion is incident into the incidence surface of the light guide and emitted from the emission surface, the backlight unit is driven by local dimming in which at least two point light sources among the plurality of point light sources are used as a minimum point lighting unit, the light guide includes a plurality of light advancing direction conversion portions and a plurality of light extraction portions, each of the light advancing direction conversion portions is provided at each of positions on the incidence surface facing the plurality of point light sources and changes an advancing direction of each of light components to a direction in which the light component is guided in the light guide, and each of the light extraction portions is provided per unit region corresponding to the minimum point lighting unit in a state where a density in a peripheral portion of the unit region is set to be higher than a density in a center portion of the unit region and emits the light guided in the light guide.