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US 4,303,290 AGranted
Method of evacuating a fluorescent lamp bulb
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsShinichi Tsunekawa, Makoto Hojo
Life of this patent
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Abstract
A fluorescent lamp bulb is first decompressed to a pressure level higher than a prescribed final seal pressure, and a desired gas is introduced into the bulb and is expelled, while maintaining the intrabulb pressure at a level attained in the first decompression step. Then the intrabulb pressure is reduced from the maintained pressure level to the prescribed final seal pressure.
Claims3
A method of evacuating a fluorescent lamp bulb comprising:
- a first decompression step of decompressing a fluorescent lamp bulb, on the inner wall of which a fluorescent layer is deposited, and both ends of which are provided with an electrode and are are connected to first and second evacuation tubes, to a pressure level higher than a prescribed final seal pressure through the first evacuation tube;
- a flow step of, while maintaining the intrabulb pressure at the level attained in the first decompression step, introducing a desired gas into the bulb through the second evacuation tube and expelling the gas through the first evacuation tube to fill the bulb with said gas at said pressure level;
- and
- a second decompression step of decreasing the intrabulb pressure from the level attained in the first decompression step to the prescribed final seal pressure.
1 more element
Dependencies are inferred from the claim text.