PURPOSE: To enable the fracture of a glass bulb and the burning of a stabilizer at the end of lamp service life with the application of high pressure pulse voltage to be effectively prevented by pertinently selecting the structure and size of a ferroelectric ceramic capacitor.
CONSTITUTION: A ferroelectric ceramic capacitor 2 is connected in parallel to a light emitting tube 1 having discharge gas sealed, and both of the capacitor 2 and the tube 1 are housed in an outer bulb 5 internally kept at a high degree of vacuum. In this capacitor 2, an electrode film of silver paste or the like is formed on both sides of a ceramic substrate, and further the film is coated with a ferroelectric crystallized glass paste, except a lead terminal section. Then, a lead terminal is bonded to the lead terminal section, thereby forming the capacitor 2. Also, elements such as a distance between the periphery of a silver film electrode so formed and the periphery of a ceramic substrate, and the thickness of the ferroelectric crystallized glass film, are pertinently selected. According to this construction, the discharge of the capacitor 2 can be prevented at the time of lighting. On the contrary, the discharge of the capacitor 2 is caused at the end of lamp service life for eliminating the capability of generating high pressure pulse voltage. Thus, the fracture of a glass bulb or the like can be effectively prevented.
SHIINA KIJIROU
SASAKI SHUNICHI
