Ultraviolet irradiation device and method

An ultraviolet irradiation method employing an ultraviolet irradiation device that includes:

• a housing having an open end and an a closing end of ultraviolet transparency;
• an ultraviolet light-emitting diode accommodated in the housing, the ultraviolet light-emitting diode emitting ultraviolet rays therefrom to outside of the housing through the closing end;
• and a heat discharge block provided at or adjacent to the open end of the housing and having a body extending in a direction opposite to the closing end, the ultraviolet irradiation method comprising:
• arranging the ultraviolet irradiation device in a container containing therein to-be-treated-liquid in such a manner that the ultraviolet irradiation device is fixed to the container, via a portion of the body of the heat discharge block adjacent to a distal end of the body extending in the direction opposite to the closing end, with the closing end of the housing projected in the container;
• irradiating the to-be-treated liquid with ultraviolet rays from the ultraviolet light-emitting diode while at least the closing end a portion of the housing contacts the to-be-treated liquid in the container;
• and
• cooling heat generated from the ultraviolet light-emitting diode by cooling the housing with the to-be-treated liquid contacted thereto and discharging the heat conducted through the housing by the heat discharge block.