Single-ended low-pressure discharge lamp, such as fluorescent lamp, and method of its manufacture

US4599536A · kind A · utility

Assignee

• Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH · DE

Inventors

• Gerhard Steeger · Augsburg, DE
• Josef Plischke · Augsburg, DE

Key dates

• Filing date: Feb 21, 1984
• Grant date: Jul 8, 1986
• Expiry date: Feb 21, 2004

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J9/34
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A single-ended low-pressure discharge lamp, such as a fluorescent lamp, is ade by providing an inner glass base structure which has a depending portion (2) extending towards the base (14) of the lamp, and an upper flange or rim portion (3) to which the bulb (10) is melted-on as a last step. Two U-shaped tubes (5, 5') are melted-in into an oval deformed region of the depending projecting end portion (2), a pre-heatable electrode (12, 12') being also located within the end region (8, 8a) of the U-shaped tubes, so that, in one working step, after deformation of the glass U-shaped tubes and the glass inner base structure, a press operation will seal together the electrodes within the ends of the U-shaped tubes, the glass of the U-shaped tubes and the inner base structure. The glass of the U-shaped tubes is coated with a phosphor, resulting in a long discharge path, through both of the U-shaped tubes, permitting direct replacement of screw-type based incandescent lamps by the thus formed fluorescent unit, after placing a bulb over the U-shaped tube and attachment to the rim, and introducing a fill including mercury. The axially depending end portion, being generally oval in cross sectio…