Hot-cathode fluorescent lamp

Abstract

A hot-cathode fluorescent lamp includes a pair of filament coils (4) at the respective ends of a glass bulb. Each filament coil (4) has a coiled portion (4a) coated with an electron emissive material, a first lead portion (4b) extending from one end of the coiled portion (4a), and a second lead portion (4c) extending from another end of the coiled portion (4a). The first lead portion (4b) and the second lead portion (4c) are connected to lead-in wires inserted into the glass bulb via connecting members (5a, 5b). At least one insulating member (11a or 11b) is provided between closest edges of the connecting members (5a, 5b) to each other. The provision of the insulating member prevents a short circuit occurring between the closest edges of the plate-shaped connecting members during lighting. Occurrence of such a short circuit would cause lighting to start without the coil portion being sufficiently pre-heated, which results in excessive sputtering of the electron emissive material to shorten the lamp life.

Dependencies are inferred from the claim text.