PURPOSE: To provide a high efficient electrodeless lamp by operating the electrodeless fluorescent lamp, with a fluorescent material emitting light by an ultraviolet ray excitation radiated by a discharge, to make a total surface become luminous except a part necessary for supplying power, in a discharge vessel lighted by high frequency power.
CONSTITUTION: A lamp, when lighted, is connected to a commercial power supply, to supply high frequency power to an excitation coil 20 from a lighting circuit 12. Normally, since the excitation coil 20 is placed in a resonance condition between itself and a resonance capacitor provided in the lighting circuit 12, voltage across both ends of the excitation coil 20 becomes high voltage, to generate intensive electric field in a coil axial direction in the vicinity of the coil. By this electric field, a discharge breakdown is generated to start a discharge. Thereafter by a high frequency electromagnetic field generated around the coil, ring-shaped high frequency plasma concentrical to the coil is generated around the coil. An ultraviolet ray generated from this high frequency plasma, irradiating a phosphor 2, is converted into visible light and taken out to outside a discharge vessel 1. Here is excepted an ordinary base part for introducing commercial power, to cover a total unit with a luminous surface, so as to realize high efficiency.
TAKAHASHI TADASHI
NISHIYAMA TAKANORI
MORIYA TOSHIYUKI
