| 摘要 |
In a dwarf lamp having a flattened pinch seal forming the base, a thin-walled copper tube for use for exhausting and gas filling is included in the pinch seal and is closed by mechanical pinching close to the point of emergence from the seal. Tubes of semi-hard copper having a diameter of less than 1.5 mm. are used with lamps produced from soft glasses, particularly lead and lime-magnesia glasses. The tube may initially be degreased, reduced with hydrogen, surface oxidized and coated with glass, treated with borax or enamelled. Alternatively, the copper tube may be treated with suspension of equal parts of water and lead borate with about 1% of magnesium chloride. The invention is particularly applicable to photo-flash lamps containing zirconium shavings in an atmosphere of oxygen. The tube may project from the base of the lamp and may be coated with insulating material, e.g. thermoplastics, to serve also as a partition between the lead-in wires which project from the base to form the base contacts. A completed photo-flash lamp comprising an envelope 5 closed by a pinch seal 6 through which pass the lead-in wires 9a, 9b which are then bent back against the pinch, and the exhaust tube 11, is shown in Fig. 4. The Specification sets out seven further arrangements of lead-in wires outside the pinch. It is also stated that the exhaust tube may be used as one of the lead-in wires or that both these may be formed as exhaust tubes. When it is not desired so to use the exhaust tube, the tip may be coated with a tear-shaped coating of thermoplastic material by dipping in a bath of heated material and, after this has cooled, carrying out a second brief dipping. A cap-shaped coating may be produced by applying the tip of the exhausts tube to a ball valve in the bottom of a container for heated thermoplastic material. |
