Patent ID: 6229257
Filing Date: 2001-05-08
Classification: C03C,H01J

Abstract:
A fluorescent lamp comprising:a glass bulb whose inner surface is coated with a fluorescent substance;a glass bead attached to an end of the glass bulb so as to seal the glass bulb;an exhaust tube provided in the glass bead and sealed;a filament coil arranged in an internal portion of the glass bulb; andan electrode terminal member electrically connected to the filament coil,wherein the glass bead controls a position of the electrode terminal member, and further wherein,the glass bulb, the glass bead, and the exhaust tube have substantially the same composition, and further wherein,the glass bulb, the glass bead, and the exhaust tube contain silica as a main component, and have a composition substantially not containing lead, and further,the glass bulb has a composition comprising:65 to 73 wt % of SiO.sub.2 ;1 to 5 wt % of Al.sub.2 O.sub.3 ;0.5 to 2 wt % of Li.sub.2 O;5 to 10 wt % of Na.sub.2 O;3 to 7 wt % of K.sub.2 O;0.5 to 2 wt % of MgO;1 to 3 wt % of CaO;1 to 10 wt % of SrO;1 to 15 wt % of BaO;0 to 2 wt % of Sb.sub.2 O.sub.3 ;0 to 0.05 wt % of Fe.sub.2 O.sub.3 ; andB.sub.2 O.sub.3, which is present in an amount no more than 3 wt %.