Backlight device and liquid crystal display device

A liquid crystal display device comprising:

• a backlight comprising:
• a plurality of light guide plates overlapping each other with a same light output direction, each of the light guide plates including a plurality of stripe-shaped projections aligned on a light output face and a light output pattern making a part of the light output face emit light at relatively high brightness;
• a plurality of light sources, each emitting light incident into any one of the plurality of light guide plates and propagating in an extending direction of the stripe-shaped projections;
• and
• a light-source substrate including a plurality of interconnections, a turning-on signal being selectively supplied via the interconnections to at least one of light source groups, each of the light source groups including at least one of the light sources, and and at least one part of a light emission face emitting light output from the light source group receiving the turning-on signal, the light emission face including the light output faces overlapped on plan view from the light output direction.