Circuit device of emitting heat and backlight unit comprising thereof

A backlight unit, comprising:

• a light source unit including a plurality of light sources;
• a light guide plate reflecting light of at least one of the light sources to a liquid crystal display panel;
• and
• a circuit device including a first circuit unit electrically connected to the light source unit and the first circuit unit having a long side extending in a first direction, a second circuit unit receiving a control signal controlling the light source unit and the second circuit unit having a long side extending in a second direction perpendicular to the first direction, and at least one heat emitting unit connected to one side of the first circuit unit to cover the outside of the light source unit,
• wherein the first circuit unit and the second circuit unit are directly in contact with an upper surface of the at least one heat emitting unit,
• wherein the first circuit unit and the second circuit unit include a common electrically conductive layer directly on the at least one heat emitting unit so that the first circuit unit and the second circuit unit are coplanar and in contact with each other,
• wherein the first circuit unit and the second circuit unit further include respective insulating layers, and the respective insulating layers are directly on one side of the common electrically conductive layer,
• wherein the second circuit unit extends away from the first circuit unit from a contact portion at which the first and second circuit units are directly in contact with each other, and
• wherein the first circuit unit overlaps at least a part of the at least one heat emitting unit in a plan view such that one end of the first circuit unit and one end of the at least one heat emitting unit are in exact alignment.