HOT CATHODE FLUORESCENT LAMP

摘要

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. Each coiled portion is covered by a heat-resistant sleeves (7). At least a region of the inner circumferential surface of the sleeve is electrically insulating. The insulating region prevents a short circuit between the coiled portion of the filament coil and the inner circumferential surface of the sleeve that would otherwise occur upon 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.