Patent ID: 7931280

Claim:
A control unit for controlling an electric discharge lamp, the control unit comprising: an electronic component in which a circuit element is implemented, the electronic component having a connector section for connection to an outside of the electronic component, the electronic component defining an annular protrusion formed around the connector section; and a casing that houses the electronic component and includes a base having a through hole and first and second annular concave grooves on which the electronic component is mounted and a cover that covers the base, wherein the through hole is formed at a position corresponding to the connector section of the electronic component to connect the connector section and an electric discharge lamp-side connector section of the electric discharge lamp, the first and second annular concave grooves are arranged surrounding the through hole on an inner side of the base at which the electronic component is mounted, the second annular concave groove is formed between the first annular concave groove and the through hole, the annular protrusion of the connector section of the electronic component is disposed within the first annular concave groove to seal the through hole with the electronic component on the inner side of the base, the first annular concave groove includes a U-shaped groove, the U-shaped groove having a closed path, the annular protrusion includes a U-shaped ridge extending from a surface of the connector section of the electronic component, a shape of the annular protrusion corresponds to a shape of the first annular concave groove, the first annular concave groove and the annular protrusion are connected to each other via adhesive, and the electric discharge lamp is connected to the control unit air tightly so that the electric discharge lamp covers the through hole from the outer side of the base, the control unit switching the electric discharge lamp ON/OFF.