Patent ID: 8368843

Claim:
A backlight unit, comprising: a light emitting block; a mounting substrate on which the light emitting block is mounted; a light guide plate that receives light coming from the light emitting block, the light guide plate allowing the light to pass therethrough and guiding the light to an outside thereof; a housing in which the light emitting block, the mounting substrate, and the light guide plate are housed, wherein the housing includes: a bottom section that supports the light guide plate; a wall section that rises from the bottom section; and a protrusion section that is supported by the wall section, protrudes toward the bottom section, and extends in a direction that intersects a direction in which the wall section rises, and the protrusion section is at least part of a first groove in which the mounting substrate is held, wherein one of the first groove is formed for one of the mounting substrates and wherein there exists, along a length of the first groove, a first narrow groove width at which the first groove is in close contact with both a mounting surface and a non-mounting surface of the mounting substrate, and a first wide groove width that is wider than the first narrow groove width.