Abstract: A method for producing a discharge lamp of the present invention includes the steps of: preparing a glass pipe for a discharge lamp having a luminous bulb portion and a side tube portion, and a single electrode assembly including an electrode structure portion that will be formed into a pair of electrodes of the discharge lamp; inserting the single electrode assembly into the glass pipe for a discharge lamp such that the electrode structure portion of the single electrode assembly is positioned in the luminous bulb portion of the glass pipe for a discharge lamp; forming a luminous bulb in which the electrode structure portion is arranged inside by attaching the side tube portion of the glass pipe for a discharge lamp to a part of the single electrode assembly; and forming a pair of electrodes in the luminous bulb by melting and cutting a part of the electrode structure portion selectively.

Abstract: A discharge lamp includes a luminous bulb in which a luminous material is enclosed and a pair of electrodes are opposed to each other in the luminous bulb; and a pair of sealing portions for sealing a pair of metal foils electrically connected to the pair of electrodes, respectively. Each of the pair of metal foils has an external lead on a side opposite to a side electrically connected to a corresponding electrode of the pair of electrodes. At least one of the pair of sealing portions is provided with a reflective film on a surface of the sealing portion in a portion where a connection portion of the external lead and the metal foil is sealed. The reflective film contains a material having a reflectance larger than that of a material constituting the sealing portion.

Abstract: A discharge lamp includes a luminous bulb in which a luminous material is enclosed and a pair of electrodes are opposed to each other in the luminous bulb; and a pair of sealing portions for sealing a pair of metal foils electrically connected to the pair of electrodes, respectively. The pair of metal foils have a pair of external leads on the side opposite to the side electrically connected to the pair of electrodes, respectively. At least one of the pair of external leads is joined to a lead wire for external connection that is to be electrically connected to an external circuit by the plastic flow of a caulking member.

Abstract: A metal halide lamp includes an arc tube containing at least mercury and metal halide. A pair of opposed main electrodes extend in the arc tube. A lamp voltage is applied between the main electrodes. The main electrodes have respective distal ends which are spaced from each other by a predetermined distance “d”.

Abstract: In a metal halide lamp which includes a discharge tube (2) retaining a fill of mercury and at least one metal halide added as a luminous material, an energy density of the arc discharge portion (3) represented by a product E.times.j is in the range of 70.0.ltoreq.E.times.j.ltoreq.150.0 (VA/mm.sup.3) where E=V/d, j=I/S, assuming that I is a lamp current in amperes with a lamp voltage of V volts applied between the paired discharge electrodes in a stable lighting condition of the lamp and that each of the electrodes has a tip face (1a, 1a') of which a cut area in section is S mm.sup.2 and the gap distance is d in millimeters, and thus a high luminous flux retention rate and high luminance of an arc discharge portion can be accomplished with a longer life of the lamp, suppressing a lamp voltage varying rate, and avoiding a change in color temperature, which remarkably improves additional merits when in utilization as a light source in various display apparatuses such as optical projection systems.