Projector light source device having projections regulating cooling airflow

A light source device, comprising:

• an arc tube having a tube spherical portion containing a pair of electrodes disposed along an illumination axis, and a pair of sealing portions extending from both sides of the tube spherical portion;
• a reflector having a reflection portion disposed in a vicinity of one of the sealing portions of the arc tube for reflecting light emitted from the arc tube toward an illumination area;
• a flow regulating unit including:
• a plurality of projecting portions configured to regulate a flow direction of cooling air, each projecting portion of the plurality of projecting portions being configured to have a length extending along the illumination axis;
• and
• a fixing portion for fixing the plurality of projecting portions to one of the pair of sealing portions in a vicinity of the tube spherical portion, and an adhesive filled between the fixing portion and the one of the pair of sealing portions, wherein
• each of the plurality of projecting portions is disposed on a side of the fixing portion that is opposite to a side of the fixing portion on which the adhesive is disposed, and
• a virtual plane that passes through the illumination axis and extends along the length of the plurality of projecting portions is interposed between adjacent protecting portions of the plurality of projecting portions so that the adjacent projecting portions sandwich the virtual plane.