ELECTRODELESS DISCHARGE LAMP, LAMP LIGHTING DEVICE, AND ILLUMINATION DEVICE

摘要

PURPOSE:To enhance the energy transmissivity by forming a closed discharge path from a spiral discharge path part and a coupling path part coupling the two ends of the spiral discharge path part. CONSTITUTION:An inert gas and a discharging substance are encapsulated in the tube of an electrodeless discharge lamp 50. The tube is formed in a string of tube elements and consists of a spiral portion 51 and a straight coupling part 52 to couple the two ends of the spiral portion 51. Plasma produced in the lamp 50 is passed through a closed path formed by the spiral portion 51 and coupling part 52 so that a plasma ring is formed. When the power is put on, a magnetic field is generated in a coil 60 by the power supplied from a high frequency power supply, and plasma ring is formed by the energy of this magnetic field in the lamp 50, which will thus emit light. With this device, the energy transmission efficiency can be enhanced even without provision of any capacitor in the high frequency power supply circuit for compensating the leaking magnetic flux.