Electrodeless discharge lamp

摘要

An electrodeless discharge lamp is disclosed that comprises a bulb with a substance for electric discharge sealed therein, the bulb having a reentrant portion protruding inwardly along a Z-axis direction; an induction coil arranged in the reentrant portion, the induction coil having a magnetic core and a winding wound around the magnetic core; and a drive circuit for supplying the induction coil with a power from 50 kHz to 1 MHz. The bulb has an outer diameter from 65 mm to 75 mm in a direction orthogonal to the Z-axis direction, and the magnetic core has a length L in the Z-axis direction that is 1.05 times or more a length L' of the winding in the Z-axis direction, the length L being set to 41 mm or less.