Light emitting device

A light emitting device comprising:

• a housing;
• a light source unit accommodated in the housing to emit light from a light emitting window of the housing, wherein the light source unit includes a light emitting surface on which a light emitting element emitting the light is disposed, and a connection surface opposite to the light emitting surface;
• and
• a cooling unit provided to the housing to discharge heat to an outside of the housing by means of a gas, the heat being generated by the light source unit,
• wherein the cooling unit includes an introduction portion that receives a provision of the gas that is compressed, a heat exchange portion that causes the gas to receive the heat generated by the light source unit, and a circulation portion that guides the gas from the introduction portion to the heat exchange portion,
• the heat exchange portion includes a receiving port connected to the circulation portion, a heat radiation member disposed at a position opposing the receiving port that causes the gas to receive the heat generated by the light source unit, and an exhaust port that discharges the gas that has received the heat generated by the light source unit, wherein the heat radiation member is disposed on a connection surface side,
• the circulation portion includes a first flow path being connected to the introduction portion and extending along a first direction, and a second flow path being connected to the first flow path, extending along a second direction intersecting the first direction, and being connected to the receiving port of the heat exchange portion, and
• the first flow path includes a portion having a flow path area larger than a flow path area of the introduction portion.