| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact self-ballasted fluorescent lamp and a lighting system incorporating it, allowing preheating of a filament as required, even in case a deep dimmed lighting is performed by generating a connection to a low-frequency AC power supply via a dimmer, is less likely to generate a drop of the lifetime reliability, and capable of being embodied at a low cost using a comparatively simple circuit configuration. SOLUTION: The arrangement according to the present invention includes a photo- transmissive discharge vessel embodied compactly and furnished with a phosphor layer on the inside surface, a fluorescent lamp FL of such a structure that a pair of filament electrodes, having a cold resistance of 0.8-6Ω, are installed sealedly at the two ends of the discharge vessel and in its inside an ionized medium including mercury and rare gas is encapsulated, a lighting circuit means 2 furnished with a noise filter NF, a rectifying DC power supply RDC, at least one switching means Q1 and Q2, and a load circuit LC and making high-frequency lighting of the fluorescent lamp, by controlling to generate such a condition that the at-preheating resistance to cold resistance ratio of the filament electrodes E1 and E2 at time out of dimming is between 3.0-4.5 and their at-preheating resistance to cold resistance ratio at the dimming time is between 4.0-5.5, a cover, in which the lighting circuit means is accommodated, and a lamp base. |
