Patent ID: 7928644

Claim:
A low pressure discharge lamp having a double helix shape comprising: a lamp base and an envelope connected to the lamp base, the envelope having a phosphor coating on an interior surface thereof and containing a gas fill energizable to a discharge state by electrical voltage, the envelope including discharge tube sections wound helically about a longitudinal axis and fitted into each other as a double-start thread, the discharge tube sections having first end portions and second end portions, the first end portions being closer to the lamp base and each having a gas-tight sealing and electrodes in the sealing for receiving the electric voltage, the second end portions being farther off the lamp base and each having a gas-tight sealing, the second end portions being bent inwardly from a pitch of the helix and extending next to each other spaced apart by a clearance, a passageway formed between said second end portions and spaced apart by a distance from the sealing of each said second end portion.