Abstract: A mercury-free metal halide lamp includes an arc tube having a pair of electrodes opposed to each other inside the tube. In the arc tube, a rare gas and a halide of cerium are contained, and no mercury is contained.

Abstract: A mercury-free metal halide lamp includes an arc tube including a pair of electrodes inside the tube. In the arc tube, a rare gas and a metal halide are contained, and no mercury is contained. The mercury-free metal halide lamp is horizontally operated such that the pair of electrodes is substantially horizontal. The mercury-free metal halide lamp further includes magnetic field applying means for applying a magnetic field including a component substantially perpendicular to a straight line connecting heads of the pair of electrodes in a substantially vertical direction. The density of halogen atoms evaporated during steady-state operation with respect to unit inner volume of the arc tube is 20 &mgr;mol/cc or more.

Abstract: A mercury-free high-intensity discharge lamp operating apparatus includes a horizontally operated high-intensity discharge lamp including an arc tube in which a luminous material is enclosed and a pair of electrodes are arranged in the arc tube; a ballast including an alternating current generation means for supplying alternating current to the pair of electrodes; and a magnetic field application means for applying in substantially vertical direction a magnetic field having a component that is substantially perpendicular to a straight line connecting heads of the pair of electrodes; wherein mercury is not included as the luminous material in the arc tube.

Abstract: A lamp made of a tube having a light emission portion glass and a side tube portion glass that extends in the light emission portion glass. The lamp has a sealed electrode assembly having an electrical current supply line with one end portion connected to a metal foil. A first portion of the side tube portion where an electrical current supply line is located is heated and this portion is compressed by a first pressure. A second portion of the side tube portion where a metal foil is located is heated and this portion is compressed by a second pressure. The second pressure is made larger than the first pressure.

Abstract: A high-pressure discharge lamp includes a glass housing made of a high-melting vitreous material, a pair of sealing components made of the same high-melting vitreous material and extended from the glass housing. A rare gas and a material that is solid or liquid at room temperature is sealed inside the glass housing. Electrically conductive bars are embedded in the sealing components. The air-tight seals around the electrically conductive bars are formed such that at least one metal material selected from metals and oxides of said metals is provided near the regions lying between the high-melting vitreous material and the electrically conductive bar.

Abstract: In a high intensity discharge lamp, at least one of an arc bend amount and an apparent width of arc is controlled by a simple configuration at low cost. A high intensity discharge lamp system 110 has a high intensity discharge lamp 111 and an operating circuit 113 for driving the high intensity discharge lamp 111. In the high intensity discharge lamp 111, a rare gas and a filling material 136 containing a metal halide as a light generating substance are enclosed in the arc tube 121 provided with a pair of electrodes 122a and 122b. The lamp system is disposed such that the line connecting the electrodes 122a and 122b is horizontal, and by applying a magnetic field having a vertical magnetic flux thereto and by varying the frequency of alternating current for driving the high intensity discharge lamp 111, at least one of an arc bend amount and an apparent width of arc can be easily controlled.

Abstract: A high-pressure discharge lamp includes a glass housing made of a high-melting vitreous material, a pair of sealing components made of the same high-melting vitreous material and extended from the glass housing. A rare gas and a material that is solid or liquid at room temperature is sealed inside the glass housing. Electrically conductive bars are embedded in the sealing components. The air-tight seals around the electrically conductive bars are formed such that at least one metal material selected from metals and oxides of said metals is provided near the regions lying between the high-melting vitreous material and the electrically conductive bar.

Abstract: A method for manufacturing a high-pressure discharge lamp of the double-ended type having excellent resistance to high-pressure and wherein the internal diameter of a portion of the high-pressure discharge lamp where a light-emitting section and a side tube are adjacent can be reduced without restricting the maximum diameter of an electrode on a side where it projects into the light-emitting section. An electrode assembly 105 is arranged within an evacuated glass bulb 2 such that an end of electrode 102 where a coil 102b is wound is positioned within the light-emitting section 3. In this condition, the portion where the light-emitting section 3 and the side tube 4a (4b) are adjacent is heated by a burner 300. The internal diameter of the side tube 4a (4b) can thereby be formed with a reduced-diameter section 7, whose diameter is smaller than that of the electrode rod 102a without restricting the diameter at the location of the coil 102b.

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.