Backlight unit and liquid crystal display device

A backlight unit comprising:

• a light source;
• a light guide member which includes an input surface from which light from the light source is input and an output surface that outputs the light input from the input surface, leads the light that is input from the input surface toward a predetermined transmitting direction, and outputs the light from the output surface;
• an optical path changing portion which includes a plurality of inclined surfaces that are inclined at a predetermined inclination angle with respect to the output surface, and changes an optical path of the light according to each of the plurality of the inclined surfaces such that the light output from the output surface travels substantially along a normal line direction of the output surface;
• and
• a light gathering portion including a plurality of light gathering surfaces each of which is disposed for each of the plurality of the inclined surfaces, and gathers light from the corresponding inclined surface toward the normal line direction of the output surface;
• wherein
• each of central positions of the plurality of the light gathering surfaces in the transmitting direction is substantially aligned with a central position of a corresponding one of the inclined surfaces in the transmitting direction.