Patent attributes
In an electrodeless discharge lamp suitable for use at a place with unfavorable environmental conditions or at a place where lamp replacement is difficult, the replacement of a lamp unit is facilitated and the lamp unit is prevented from falling off from a power coupler unit even if there is component deterioration caused by long-term use. A metallic elastic member is provided near a position on a metallic heat conduction member of the power coupler unit that is farthest from an electromagnetic field generating portion. In addition to an ordinary coupling structure between the power coupler unit and a coupling member, the elastic member is engaged with the coupling member of the lamp unit. When the lamp unit is mounted on or removed from the power coupler unit, a bulb of the lamp unit is turned relative to the power coupler unit about the axis and moved forward/backward in the direction of the axis. This causes the elastic member to be elastically deformed by the coupling member and engaged to or separated from a coupling portion provided at the coupling member.
