Abstract: The arc tube is provided with a mercury-free arc tube main body that has a discharge light-emitting portion (closed glass sphere), and a cylindrical shroud glass tube that is airtightly integrated with the arc tube main body. In the mercury-free arc tube in which an inert gas is sealed in the shroud glass tube that surrounds the closed glass sphere, in the shroud glass tube, the adjustment is made so as to satisfy the light flux and the life span with respect to the pressure X (atmospheric pressure) of a rare gas sealed in the closed glass sphere, and an amount M (mg/ml) of sealed metal halide.

Abstract: An arc tube for a discharge bulb is provided for use in a vehicular lighting system. The arc tube includes a closed glass bulb that is pinch-sealed at opposite ends. Inner ends of a first electrode and a second electrode extend into the closed glass bulbs from the ends of the closed glass bulb. The atmosphere inside the closed glass bulb includes a starting rare gas, a primary light-emitting metal halide, and optionally, a buffer metal halide. The distance between the inner ends of the electrodes is between about 0.3 and 1.8, and the inner diameter of the closed glass bulb at a middle portion is between about 1.5 mm and 2.7 mm. Accordingly, a stable discharge is produced using between 15 W and 30 W of power.

Abstract: In an arc tube for discharge lamp, an electrode assembly is formed by integrally joining an electrode rod, a molybdenum foil, and a molybdenum lead wire. The electrode assembly is sealed into pinch seal portions located at both ends of a glass tube. The electrode assembly, before being pinch-sealed into the pinch seal portions, receives vacuum heat treatment at 200 to 800° C. Hereby, the water content of the assembly is adjusted to 10 ppm or less, and desirably to 3 ppm less and an oxide film attached to the surface of the electrode assembly is removed. Therefore, the quantity of impurity (water or gas) enclosed in the closed glass bulb is very small, so that it is possible to provide an arc tube in which the flicker is not produced, luminous flux of 3000 lm or more is obtained, and starting voltage can be lowered to about 15 kV.

Abstract: A mercury-free arc tube for a discharge lamp unit including a closed glass bulb and a pair of electrode rods provided in the closed glass bulb so as to be opposite to each other. The closed glass bulb does not contain mercury as in the related art arc tubes, but contains main light emitting metal halide and starting rare gas enclosed in the closed glass bulb. In accordance with necessity, predetermined buffer metal halide in place of mercury may be enclosed to suppress the lowering of the tube voltage to some extent. In addition, the tube current I is increased to make the tube voltage high. The tube current I (unit: A) and the outer diameter d (unit: mm) of each electrode rod are set to have a relationship of 1.0?I/d?5.0. As a result, though such an increased tube current is used, the electrode temperature is kept in optimum temperature.

Abstract: In a mercury-free arc tube, electrodes are configured by electrode rods heat-treated at 1,200 to 2,200° C. in a vacuum atmosphere, and which have a thickness of 0.3 mm or more. The size (radius R) of a residual compression strain layer formed around the electrode rod is set to be ¼ or less of the width D of the pinch seal portion. A glass layer outside the residual compression strain layer is thickened, thereby enhancing the strength of the pinch seal portion.

Abstract: A discharge bulb is provided with an arc tube main body in which an arc tube having a discharge light emitting portion (a hermetically sealed glass envelope) where electrodes are provided in such a manner as to face each other is enclosed in a cylindrical shroud glass tube. The discharge bulb is configured so that a light distribution pattern having a predetermined cut-off line is formed by light intercepting portions (light intercepting films) and a light distribution control reflector. A frost treatment is applied to only a light emitting area on an outer surface of the shroud glass tube which corresponds to an area along the cut-off line in the light distribution pattern.

Abstract: A mercury free arc tube for a discharge lamp has a closed chamber filled with rare gas and a metal halide containing at least Na halide, Sc halide and In halide, and electrodes. A ratio of a filled amount of the In halide to a total filled amount of metal halide is ranging from 0.1 to 2.0 wt %. When the ratio of the charging amount of InI is 0.1 wt % or more, the chromaticity x, y of a luminescent color during a stable discharge falls within a chromaticity standard range A of white light source. When the ratio of charging amount of InI is 2.0 w % or less, a chromaticity y minimal value of luminescence of the arc tube at the transient time is 0.29 or more, whereby purplish red color is less conspicuous and there is no fear that an emission of the arc tube is misidentified a red marker lamp.

Abstract: An arc tube for a discharge lamp has a closed chamber filled with rare gas and a metal halide containing at least Na halide or Sc halide, and electrodes, wherein sealing pressure of the rare gas is 0.6 MPa or more, and a sealing density of the Sc halide in the closed chamber is ranging from 1.25 to 4.70 mg/ml. In the arc tube, since the Xe gas sealing pressure slightly higher than 0.6 MPa, the pressure in the closed chamber is increased during its lightening state. Thus, reactions leading to a flicker occurrence may be accelerated. However, the flicker occurrence can be suppressed by setting the Sc halide sealing density to 4.70 mg/ml or less. Further, a luminous efficiency required for the lamp can be assured by setting the Sc halide sealing density to 1.25 mg/ml or more.

Abstract: A mercury-free arc tube for a discharge lamp has a closed chamber filled with rare gas and a metal halide containing at least Na halide or Sc halide and electrodes disposed on both end portions of the closed chamber so as to be opposed to each other, wherein the electrode rod is stepped shape which satisfies relationship of 1.1<A1/A2<7.3, whereas A1 is a cross sectional area of the electrode in a top-end side area protruded into the closed chamber and A2 is a cross sectional area of the electrode in a base-end side area fixed to the end portion of the closed chamber.

Abstract: A mercury-free arc tube having a closed glass bulb held between pinch seal portions located at opposite ends of the closed glass bulb and a pair of electrodes provided in the closed glass bulb. The closed glass bulb does not contain mercury (Hg), but contains a main light emitting, a buffer metal halide, and a starting rare gas enclosed in the closed glass bulb. The buffer metal halide includes a halide selected from halides of Ta, Th, Cu, Rb, Nb and Pd. Preferably, at least one of the halides is Ta, Cu, Rb or Nb. The halides serve as a buffer substance and a light emitting substance in substitution for the mercury, and have an ionization potential of about 5 to 8.5 eV and excitation potential of about 4.5 eV or less having emission spectrum in a visible range, and are sealed with the rare gas.

Abstract: An arc tube for a discharge bulb is provided for use in a vehicular lighting system. The arc tube includes a closed glass bulb that is pinch-sealed at opposite ends. Inner ends of a first electrode and a second electrode extend into the closed glass bulbs from the ends of the closed glass bulb. The atmosphere inside the closed glass bulb includes a starting rare gas, a primary light-emitting metal halide, and optionally, a buffer metal halide. The distance between the inner ends of the electrodes is between about 0.3 and 1.8, and the inner diameter of the closed glass bulb at a middle portion is between about 1.5 mm and 2.7 mm. Accordingly, a stable discharge is produced using between 15 W and 30 W of power.

Abstract: A mercury-free arc tube includes a closed glass bulb held between pinch seal portions located at opposite ends of the close glass bulb; and a pair of electrodes provided in the closed glass bulb so as to be opposite to each other. The closed glass bulb does not contain mercury but contains main light emitting metal halide (NaI and ScI3). A rare gas is enclosed in the closed glass bulb with a charged pressure set to be in a range of from 8 to 20 atmospheres. If necessary, a predetermined buffer metal halide acting as a buffer substance is enclosed in the closed glass bulb. The charged pressure of the rare gas is higher than the conventional charged pressure (6 atmospheres).

Abstract: An arc tube and method for forming an arc tube in which an electrode assembly including a tungsten electrode and a molybdenum foil are joined together in a partially overlapped state and pinch sealed into a pinch seal portion of the arc tube body to suppress leakage due to peeling of the molybdenum foil and prolong the life period of the arc tube. An overlapped length L1 of a tungsten electrode and a molybdenum foil is set to be 2D≦L1≦0.8W with respect to the diameter D of the tungsten electrode and the width W of the molybdenum foil. In another embodiment, the distance L2 between the molybdenum foil and a discharge space is set to be B≦L2≦0.8A with respect to the width A and the thickness B of a pinch seal portion.

Abstract: A mercury-free arc tube having a closed glass bulb held between pinch seal portions located at opposite ends of the closed glass bulb and a pair of electrodes provided in the closed glass bulb. The closed glass bulb does not contain mercury (Hg), but contains a main light emitting, a buffer metal halide, and a starting rare gas enclosed in the closed glass bulb. The buffer metal halide includes a halide selected from halides of Ta, Th, Cu, Rb, Nb and Pd. Preferably, at least one of the halides is Ta, Cu, Rb or Nb. The halides serve as a buffer substance and a light emitting substance in substitution for the mercury, and have an ionization potential of about 5 to 8.5 eV and excitation potential of about 4.5 eV or less having emission spectrum in a visible range, and are sealed with the rare gas.

Abstract: A mercury-free arc tube for a discharge lamp unit including a closed glass bulb and a pair of electrode rods provided in the closed glass bulb so as to be opposite to each other. The closed glass bulb does not contain mercury as in the related art arc tubes, but contains main light emitting metal halide and starting rare gas enclosed in the closed glass bulb. In accordance with necessity, predetermined buffer metal halide in place of mercury may be enclosed to suppress the lowering of the tube voltage to some extent. In addition, the tube current I is increased to make the tube voltage high. The tube current I (unit: A) and the outer diameter d (unit: mm) of each electrode rod are set to have a relationship of 1.0≦I/d≦5.0. As a result, though such an increased tube current is used, the electrode temperature is kept in optimum temperature.

Abstract: A mercury-free arc tube includes a closed glass bulb held between pinch seal portions located at opposite ends of the close glass bulb; and a pair of electrodes provided in the closed glass bulb so as to be opposite to each other. The closed glass bulb does not contain mercury but contains main light emitting metal halide (NaI and ScI3). A rare gas is enclosed in the closed glass bulb with a charged pressure set to be in a range of from 8 to 20 atmospheres. If necessary, a predetermined buffer metal halide acting as a buffer substance is enclosed in the closed glass bulb. The charged pressure of the rare gas is higher than the conventional charged pressure (6 atmospheres).

Abstract: An arc tube and method for forming an arc tube in which an electrode assembly including a tungsten electrode and a molybdenum foil are joined together in a partially overlapped state and pinch sealed into a pinch seal portion of the arc tube body to suppress leakage due to peeling of the molybdenum foil and prolong the life period of the arc tube. An overlapped length L1 of a tungsten electrode 26 and a molybdenum foil 30 is set to be 2D≦L1≦0.8 W with respect to the diameter D of the tungsten electrode 26 and the width W of the molybdenum foil 30, whereby occurrence of peeling of the molybdenum foil 30 is effectively suppressed while effectively suppressing occurrence of breakage of the molybdenum foil 30. In another embodiment, the distance L2 between the molybdenum foil 30 and a discharge space 24 is set to be B≦L2≦0.

Abstract: An insulating plug, for a discharge lamp device, including a plug body and a lamp-side connector. The plug body is made of a glass-fiber-reinforced plastic resin. The lamp-side connector is provided at a rear end portion of the plug body. A power-supplying connector can be attached to, and detached from, the lamp-side connector. The plug body has an arc tube fixedly held thereon, so as to form a discharge lamp device. Because the plug body is made of a glass-fiber-reinforced plastic resin, the durability, molding precision, and so on of the plug body and, hence, those of the discharge lamp device provided with this plug body, are enhanced.