Patent ID: 8299697

Claim:
A high performance fluorescent lamp, comprising: an air-tight glass envelope having at least two sealed ends and a light cavity therein, wherein said light cavity is filled with inert gas and coated with a phosphor powder at an inner wall of said light cavity; two electrodes each having a filament being supported at said two sealed ends of said glass envelope respectively, wherein a tubular tail pipe, defining a channel therein, is integrally formed at one of said sealed ends of said glass envelope at a location communicating with said light cavity; and means for retaining an amalgam in said channel at a position forming a predetermined distance between said amalgam and one of said filaments sealed at said corresponding sealed end; wherein said means is a narrow opening provided at a predetermined position along said channel, wherein said narrow opening has a diameter smaller than that of said channel and said amalgam contained in said channel is blocked by said narrow opening to retain between said narrow opening and a distal end of said tail pipe so as to retain said predetermined distance between said respective filament and said amalgam, thereby by configuring said predetermined distance between said filament and said amalgam, said fluorescent lamp is adapted to be operated under various ambient temperatures or various wattages without substitution of said amalgam.