A method of producing a lamp having a coated layer and of a type in which linear tubes in parallel are interconnected, comprises the steps of forming a connected glass tube by making an airtight connection via connecting portions between side walls of a plural number of glass tubes having openings at both ends and main portions that are linear and arranged parallel to each other; of forming a coated layer on the inner wall surface of the connected tube including the connecting portions by introducing a coated substance from opening end portions of the connected glass tube; and of forming an airtight path as a discharge path in the connected tube including the main and connecting portions by sealing the opening end portions on a side of the connecting portions of the connected tube after the formation of the coated layer.
In a method for manufacturing a fluorescent lamp, four dual tubes that are previously manufactured are held at a distance in such a manner that the dual tubes can move horizontally. Four portions for connection are simultaneously heated, and two of the dual tubes are simultaneously moved horizontally to form bridge portions to provide tube assemblies. Furthermore, annealing after bridge connection and the connection of tube assemblies with a bridge are performed simultaneously. Thus, a compact fluorescent lamp comprising eight glass tubes that are connected with bridges to form continuous discharge paths can be obtained. According to the manufacturing method, bridge connection can be performed in a small space and with high productivity, and a fluorescent lamp having a good quality with minor variations in the quality of the bridge portions can be provided.
An object of the present invention is to provide, without increasing the costs or decreasing the quantity of light, a fluorescent lamp that is less likely to have the bridge and the constituent tubes damaged while being handled and has improved handleability, as well as to provide a manufacturing method therefor. It is arranged so that the distance between the first and second constituent tubes gradually becomes smaller from the base side of the lamp toward the turning portion side of the lamp where the discharge paths turn. It is arranged so that the value of D2/D1 is within a range of 0.05 to 0.70 inclusive, where D1 is the distance between the first and second constituent tubes being measured at the bridge connecting points on the base side, and D2 is the shortest distance between the first and second constituent tubes on the turning portion side.
A method of producing a low-pressure mercury vapor discharge lamp comprising two or more substantially parallel co-extending glass discharge tubes includes forming an inter-connecting joint between the tubes by heating the tubes to form blisters and causing the blisters to simultaneously fuse and break, thereby forming a joint between the tubes.
A fluorescent lamp includes two glass outer tubes (6, 7), a bridge junction (8), and first glass inner tubes (9, 10). One end of each of the glass outer tubes is closed, and the other end is sealed with stems (4, 5) for supporting electrodes (13). A phosphor is applied to the inside surface of each of the glass outer tubes. The bridge junction connects the glass outer tubes at the other end portion to form a discharge space inside the glass outer tubes. The first glass inner tubes are provided in the glass outer tubes, respectively. A phosphor is applied to the surface of each of the first glass inner tubes. One end of each of the first glass inner tubes is open and disposed at the closed ends of the glass outer tubes, and the other end is sealed with the tips of the stems so that the electrodes are positioned in the first glass inner tubes.
A low pressure discharge lamp having a tubular discharge vessel (1). At each of its end portions (2, 3) the vessel (1) is fused to a respective metal tube (5) having an uncovered outer surface outside the vessel. A sealed glass tube (6) is fused to the metal tubes (5). Ignition aids (18, 28, 40) may also be present. The simple construction of the lamp permits manufacture and high lamp quality, even at long lengths and/or small diameters of the discharge vessel. The lamp may have an ionizable filling of rare gas or may also contain mercury. A fluorescent powder may also be present in the discharge vessel. The lamp (72) and a luminaire (70, 71) mounting the lamp may be used for display or signalling purposes.
