Patent ID: 6979946

Claim:
An electrodeless fluorescent lamp characterized in that the electrodeless fluorescent lamp includes: a translucent discharge vessel in which a light emitting substance is enclosed and which has a cavity portion; a coil which is disposed in the cavity portion and generates an alternating electromagnetic field for inducing discharge of the light emitting substance; and a luminophor film formed on an inside wall of the discharge vessel, and the discharge vessel includes an outer tube and an inner tube, in the inner tube the cavity portion being defined, and the luminophor film has the maximum thickness in the vicinity of the intermediate point between a connection portion of the outer tube and the inner tube and part of the outer tube which is located most distant from the connection portion, and the thickness of part of the luminophor film tapers between the intermediate point and the connection portion, whereby the luminophor film has a predetermined luminous intensity distribution characteristics.