Light irradiation device

A light irradiation device, comprising:

• a light irradiation section including a plurality of light-emitting elements being two-dimensionally arranged along a plane perpendicular to a first direction;
• and
• a cooling section including an inlet port and an outlet port, and configured to cool down the plurality of light-emitting elements by circulating a coolant from the inlet port to the outlet port,
• wherein the cooling section includes,
• a first plate-shaped portion being thermally connected to the plurality of light-emitting elements,
• a second plate-shaped portion facing the first plate-shaped portion in the first direction,
• a plurality of first wall portions each extending between the first plate-shaped portion and the second plate-shaped portion in a second direction perpendicular to the first direction, and arranged in a third direction perpendicular to both the first direction and the second direction,
• a plurality of second wall portions each extending between the first plate-shaped portion and the second plate-shaped portion in the second direction, and arranged in the third direction, and
• a frame portion surrounding the plurality of first wall portions and the plurality of second wall portions between the first plate-shaped portion and the second plate-shaped portion,
• the inlet port is disposed on one side in the third direction with respect to the plurality of first wall portions and the plurality of second wall portions,
• the outlet port is disposed on the other side in the third direction with respect to the plurality of first wall portions and the plurality of second wall portions,
• each of the plurality of first wall portions and each of the plurality of second wall portions are alternately disposed in a state of being spaced apart from each other,
• each of the plurality of first wall portions is thermally connected to each of the first plate-shaped portion and the second plate-shaped portion,
• each of the plurality of second wall portions is thermally connected to each of the first plate-shaped portion and the second plate-shaped portion,
• the frame portion is thermally connected to each of the first plate-shaped portion and the second plate-shaped portion,
• each of the plurality of first wall portions includes a plurality of first passage portions through which the coolant passes,
• each of the plurality of second wall portions includes a plurality of second passage portions through which the coolant passes,
• the plurality of first passage portions are arranged in the second direction and are biased to the second plate-shaped portion side in the first direction, and
• the plurality of second passage portions arranged in the second direction and are biased to the first plate-shaped portion side in the first direction.