JPS6212260U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a schematic cutaway diagram showing an example of an HID lamp equipped with an arc tube according to the present invention, and FIG. 2 is an explanatory diagram of a vertical cross-section of a main part of the end of the arc tube in FIG. 1, which is enlarged. 3 to 5 are longitudinal cross-sectional views of main parts showing other embodiments of the present invention, and FIG. 6 is an explanatory cross-sectional view showing the shrink-fitting state of the electrode and the conductive closure body, with the solid line indicates before shrink fitting, and the broken line indicates after shrink fitting. 2: Bulb (outer tube), 4: Base, 6: Arc tube,
8: lead member, 10: conductive member, 12: translucent ceramic tube, 14: conductive closure, 16: electrode, 18: electrode side surface of conductive closure, 20: insulating layer, 22: protrusion, 24: Gap, 30: Sealing material.

Claims (1)

[Scope of utility model registration request] An arc tube for a high-pressure metal vapor discharge lamp, in which an end of a translucent ceramic tube is closed with a conductive closing body, and an electrode and a lead member are embedded in the conductive closing body at each end, As the conductive closure, a conductive closure with an electrical resistance value of 0.1 to 5 Ω is used, and a twisted wire electrode is embedded approximately in the center of the conductive closure, while an electric current is applied to the electrode-side surface of the conductive closure. An insulating layer is provided, and the surface of the insulating layer is made to protrude in the direction in which the insulating layer is disposed around the electrode beyond the surface of the insulating layer located at the peripheral edge of the conductive closure, and the insulating layer and the electrode are An arc tube for a high-pressure metal vapor discharge lamp, characterized in that a gap is provided at a predetermined interval between the two.