Patent ID: 8579490

Claim:
A backlight device of a sidelight type, comprising: a light-emitting element; a light guide plate that includes a light incidence surface on which light from the light-emitting element becomes incident and a light output surface from which incident light is outputted to a side of a display panel; an optical sheet that is disposed in opposition to the light output surface of the light guide plate; and a resinous frame that houses the light-emitting element, the light guide plate, and the optical sheet, wherein an inclined surface inclined with respect to the light output surface is formed between the light incidence surface and the light output surface of the light guide plate, the light guide plate is formed so as to have a thickness larger at a portion on a side of the light incidence surface than at a portion on a side of the light output surface, a restriction member that has a light-blocking property and restricts the light guide plate from being moved in a thickness direction of the light guide plate is disposed forward of a portion of the light output surface of the light guide plate on a side of the light incidence surface, and the restriction member is formed integrally with the frame.