Abstract: An ultra-high pressure discharge lamp is provided having seal portions of a structure capable of realizing a pressure resistance of 100 atm or higher while ensuring a higher yield. The ultra-high pressure discharge lamp includes: a pair of mounts each comprising a metal foil having one end welded to an associated electrode and an opposite end welded to an associated external lead pin, and a preseal glass member embedding the metal foil therein; and a quartz envelope having an arc tube portion provided with a pair of seal portions on opposite sides thereof, the electrodes associated with the respective mounts being disposed opposite to each other in the arc tube portion, the preseal glass member being hermetically sealed in a respective one of the seal portions, wherein the preseal glass member has a portion fused to an inner peripheral surface of the respective seal portion over an entire circumference thereof.

Abstract: It is an object of the present invention to assuredly prevent occurrence of minute cracks in a seal portion of a lamp for improvement of the pressure resistance and service life of the lamp. To achieve the object, there is provided a seal structure of a lamp including: (a) a lamp envelope having a light emitting tube and a seal portion; (b) a metal foil embedded in the seal portion of the lamp envelope; (c) a light emitting element attached to one of opposite ends of the metal foil and disposed in the light emitting tube; and (d) an outer lead rod attached to the other end of the metal foil and led out of the seal portion, the seal structure comprising a separable layer interposed between the seal portion and a portion of the light emitting element embedded in the seal portion.

Abstract: A discharge lamp is provided which employs a higher-pressure and higher-wattage lamp body 1 and is capable of effectively preventing the scattering of broken pieces of the lamp body 1 at explosion of the lamp body 1. The discharge lamp comprises a lamp body 1, a reflector 2 having the lamp body 1, and a front glass fitted on a front portion of the reflector 2, wherein the reflector 2 has vent holes 4 in which mesh sheets 6 or perforated plates 5 are fitted.

Abstract: There is provided a novel method of lighting an ultra-high pressure discharge lamp (A1) having a discharge bulb (1) made of quartz glass in which a pair of electrodes (2) and (3) are disposed facing each other, the method including: lighting the lamp with alternating current; and providing a time period of at least one second for which the alternating current assumes a lighting frequency of 5 Hz or lower during a period for which the lamp lights, wherein the electrodes (2) and (3) each have a current withstanding capability against a current 1.5 times or more as high as a current value at which the lamp lights stably. This method enables the ultra-high pressure discharge lamp to have a longer life and exhibit a higher luminance.

Abstract: An electric discharge lamp is provided comprising; a lamp envelop including a first and a second sealing tubes both of which are sealed and a light-emitting portion located between the sealing tubes; a pier of electrodes disposed in the light-emitting portion; and a filler substance encapsulated within the lamp envelop, one of the sealing tubes having a seal-cut trace of a tip tube that has been used for introducing the filler substance into the lamp envelop therethrough.

Abstract: A metal halide lamp includes a pair of electrodes with a spacing of 0.5 to 1.5 mm therebetween, an envelope enclosing the pair of electrodes, and at least one metal halide, other than a mercury halide, that is encapsulated in the envelope in an amount of from 0.04 to 0.3 mg/cc, wherein the metal halide lamp operates in a power range from 75 to 270 watts per millimeter across the spacing between the pair of electrodes.

Abstract: A direct current discharge lamp includes: a bulb portion 1a containing therein an anode 2b and a cathode 2a; a first seal portion 5 outwardly extending from the bulb portion 1a on the anode side; a second seal portion 4 outwardly extending from the bulb portion 1a on the cathode side; a pair of feeder elements 3 respectively inserted through the first and second seal portions 5 and 4 for feeding electricity to the anode 2b and cathode 2a; and an extended tube portion 6 interconnecting the bulb portion 1a and the first seal portion 5.