Abstract: The present invention provides a metal halide lamp having a ceramic arc tube vessel that includes a discharge arc tube member and thin tube members, the discharge arc tube member including taper parts and a main tube part in the middle in a longitudinal direction, the taper parts and the main tube part having a larger outside diameter than an outside diameter of ends of the discharge arc tube in a longitudinal direction, and the thin tube members each being fit to the respective ends of the discharge arc tube, where a minimum curvature radius R is set to be 0.3 mm or more at each transitional area of an external surface between each taper part and a corresponding end of the discharge arc tube.

Abstract: To provide a high-efficiency and long-life high intensity discharge lamp that is obtained by a configuration in which a neon gas or a neon-based gaseous mixture is filled as a starting-assistance rare gas for an alumina ceramic arc tube, and a filling pressure is set to 13 kPa or more. The high intensity discharge lamp is provided with the alumina ceramic arc tube having a discharge arc tube, alumina ceramic narrow tubes formed at both end portions of the discharge arc tube, electrodes and power feeders, the electrodes and the power feeders being arranged to form spaces in the narrow tubes. The discharge arc tube is filled with the neon gas or the neon-based gaseous mixture as the starting-assistance rare gas at a filling pressure of 13 kPa or more. This prevents a discharge arc from jumping from tip portions of the electrodes to the spaces at starting of the lamp, and avoids occurrence of cracks and breakages in the narrow tubes.

Abstract: A safety metal halide lamp with a high luminous efficiency and a long lamp life is provided. The metal halide lamp includes an arc tube made of light-transmissive ceramic, in which a pair of electrodes is provided and cerium iodide (CeI3) and sodium iodide (NaI) are enclosed as a light-emitting substance, wherein a molar composition rate NaI/CeI3 of the light-emitting substance is specified within a range of 3.8 to 10, inclusive, and a wall load on the arc tube ranges from 13 to 23 W/cm2, inclusive, and on a series of X, Y coordinates, where X denotes a value of a lamp watt (W) and Y denotes a value of Le/&phgr;i, where Le and &phgr;i denote a distance between the pair of electrodes and an internal diameter of the arc tube, respectively, values of the Le/&phgr;i and the lamp watt are specified to be within a range surrounded by lines passing through the points (200, 0.75), (300,0.80), (400, 0.85), (700, 1.00), (1,000, 1.15), (1,000, 2.10), (700, 2.00), (400, 1.90), (300, 1.80), and (200, 1.

Abstract: A metal halide lamp has an arc tube including an arc tube container as an envelope made of an oxide-based translucent ceramic material such as alumina, and the arc tube is filled with cerium halide as a luminescent material and a halide of a rare earth element that is more reactive with the ceramic material than is the cerium halide. Accordingly, a reaction between the oxide-based translucent ceramic material and the halide of a rare earth element is accelerated while a reaction between the oxide-based translucent ceramic material and the cerium halide is suppressed. This suppresses a decrease of the cerium halide that serves for light emission, and also reduces changes in the lamp color temperature. Thereby, lowering of flux maintenance factor and color temperature in aging of the lamp are suppressed, and the thus provided metal halide lamp with an alumina ceramic tube for indoor and outdoor use has a white light source color and it has a high-wattage, high luminous efficiency, and a long service life.

Abstract: A metal halide lamp has an arc tube including an envelope as an arc tube container made of an oxide-based translucent ceramic material, and the arc tube is filled with luminescent materials comprising at least a cerium halide, a sodium halide, a thallium halide and an indium halide. An amount of the cerium halide is in a range from 20 wt % to 69.0 wt %, an amount of the sodium halide is in a range from 30 wt % to 79.0 wt %, and a total amount of the thallium halide and the indium halide is in a range from 1.0 wt % to 20 wt % with respect to the entire metal halides. Accordingly, the arc discharge is spread, bending of the arc discharge toward the arc tube wall is suppressed, and thus, the metal halide lamp has improved luminescent efficiency, where lowering of the flux maintenance factor is suppressed even after a long-time use, and hues of the luminescent colors are corrected.

Abstract: A metal vapor discharge lamp includes a discharge tube comprising a translucent ceramic discharge portion that defines a discharge space in which a luminous metal is sealed, slender tube portions provided on both ends of the discharge portion, a pair of electrodes provided with coils at the tips thereof, electrode supports that support the electrodes at one end thereof and extend all the way to the ends of the slender tube portions on the side opposite to the discharge space at the other end thereof, and a sealant for sealing the ends of the slender tube portions on the side opposite to the discharge space so as to attach the electrode supports to the inner surfaces of the slender tube portions, in which X>0.0056P+0.394 is satisfied, where P is a lamp power (W) and X is a distance (mm) from the ends of the coils on the side of the slender tube portions to the ends of the slender tube portions on the side of the discharge space.

Abstract: A metal vapor discharge lamp includes a discharge tube comprising a translucent ceramic discharge portion that defines a discharge space in which a luminous metal is sealed, slender tube portions provided on both ends of the discharge portion, a pair of electrodes provided with coils at the tips thereof, electrode supports that support the electrodes at one end thereof and extend all the way to the ends of the slender tube portions on the side opposite to the discharge space at the other end thereof, and a sealant for sealing the ends of the slender tube portions on the side opposite to the discharge space so as to attach the electrode supports to the inner surfaces of the slender tube portions, in which X>0.0056P+0.394 is satisfied, where P is a lamp power (W) and X is a distance (mm) from the ends of the coils on the side of the slender tube portions to the ends of the slender tube portions on the side of the discharge space.

Abstract: A metal vapor discharge lamp including an outer tube having a closed portion at a first end and a base at a second end; a discharge tube inside of which an electrode is provided, located in the outer tube; and a sleeve enveloping the discharge tube and located in the outer tube, wherein the sleeve includes an open portion on the closed portion side of the outer tube; the closed portion side of the outer tube is provided with a support for supporting an end of the closed portion side of the sleeve; the support comprises a column portion having a narrow plate shape or a narrow stick shape separated from the open portion of the closed portion side of the sleeve, and a sleeve holding portion provided at an end of the column portion and is in contact with the sleeve; and the support is connected to a feeding body connected to the electrode and led from the discharge tube toward the side of the closed portion, and the support also is connected to an electric power supply wire extending toward the side of the base.