Abstract: An ultraviolet light irradiation apparatus includes: a head including an ultraviolet LED; and a controller. The ultraviolet light irradiation apparatus further includes: a current detection resistor which is electrically connected to the ultraviolet LED and detects a current flowing through the ultraviolet LED. The controller includes: a power setting unit which sets an output power such that the ultraviolet LED emits ultraviolet light intermittently or in plural steps; a current adjustment unit which adjusts the current supplied to the ultraviolet LED according to the output power set by the power setting unit; and an output voltage supply unit which supplies a voltage to the ultraviolet LED. The output voltage supply unit adjusts the voltage supplied to the ultraviolet LED according to the current that is supplied to the ultraviolet LED and adjusted according to the output power set by the power setting unit.

Abstract: A heat sink is thermally connected to a substrate on which LED elements are mounted. A fan unit is arranged near the distal end of a fin segment of the heat sink. A vent hole is formed in a case so as to expose the base end of the fin segment entirely in a direction in which fins are aligned. The heat sink is configured such that a gap between the fins is substantially blocked in a part except where the vent hole is present. The gap is an opening extending in a width direction perpendicular to the direction in which the fins are aligned. Space between the distal end of the fin segment and the fan unit functions as a pressure chamber that is placed in a positively pressurized condition or a negatively pressurized condition by cooling air traveling from the fan unit.

Abstract: A heat sink is thermally connected to a substrate on which LED elements are mounted. A fan unit is arranged near the distal end of a fin segment of the heat sink. A vent hole is formed in a case so as to expose the base end of the fin segment entirely in a direction in which fins are aligned. The heat sink is configured such that a gap between the fins is substantially blocked in a part except where the vent hole is present. The gap is an opening extending in a width direction perpendicular to the direction in which the fins are aligned. Space between the distal end of the fin segment and the fan unit functions as a pressure chamber that is placed in a positively pressurized condition or a negatively pressurized condition by cooling air traveling from the fan unit.