Abstract: In a fluorescent lamp, an elongated envelope containing, e.g., an Argon gas is sealed by covering each end with a stem. Through this stem, a pair of leading-in wires are introduced into the interior of the envelope, such that those portions of the leading-in wires which are located inside the envelope constitute internal wire portions. A filament coil, which has an emitter coated thereon in a predetermined range, is supported between the internal wire portions. An auxiliary anode, which is connected at one end to each internal wire portion, extends inside the envelope in the discharge direction of the fluorescent lamp. The auxiliary anode is bent such that its distal end is located within the emitter-coated range, as viewed in the longitudinal direction of the filament coil, and is located close to the central axis of the discharge space, as viewed in the radial direction of the filament coil.

Abstract: A high pressure metal vapor discharge lamp comprises a light-emitting tube in which a pair of electrodes is enclosed, a starting element including a normally closed-type thermal switch and a resistive member, the starting element generating a pulse by closing and opening switch operations, a connecting element for electrically connecting the starting element to the electrodes, the pulse being applied to the electrodes through the connecting element, and a member including an insulating body provided in vicinity of the thermal switch for causing a conductive portion to be formed on the body, the conductive portion being sufficient to bypass a current supplied to the starting element by repetitions of the switch operations, thereby lowering the pulse voltage.

Abstract: A high-pressure metal vapor discharge lamp comprising an outer tube, a light emitting tube located within the outer tube and made of a light-transmissive ceramics material, and a fuse electrically connected in series with the light emitting tube, in which said fuse has such a blowing characteristic as given by the following equation and at a rated output during the lighting of the lamp the density of a current through the fuse is not more than 23.9 A/mm.sup.2 :log T.sub.1 <AlogI+BA=-1.02.times.10.sup.-2 (D.sup.2 t)-0.885B=2.64.times.10.sup.-2 (D.sup.2 t)+1.01T: required blowing time (seconds) of the fuseI: blowing current (A) of the fuseD: inner diameter (mm) of the light emitting tubet: wall thickness (mm) of the light emitting tube.

Abstract: A metal vapor discharge lamp has a burner for sealing xenon gas, mercury and a light-emitting additive in a translucent ceramic tube, a starting device of a thermal switch type which has a series circuit of a thermal switch and a coil filament and which is connected in parallel with the burner, and an outer envelope for sealing the burner and the starting device therein. In the lamp, the following inequalities must be satisfied:13.3.ltoreq.P.multidot.(B/A).ltoreq.6650.05.ltoreq.d.ltoreq.0.122,200.ltoreq.T.ltoreq.2,800where A is the volume (cm.sup.3) of the outer envelope, B is the volume (cm.sup.3) of the burner, P is a gas pressure (Pa) at room temperature of xenon sealed in the burner, d is a diameter (mm) of the coil filament, and T is a temperature (K) of the coil filament during operation.

Abstract: A metal vapor discharge lamp has a light emitting tube of translucent ceramics which includes a straight tube section of a predetermined diameter and a pair of tube end sections having their diameter gradually decreased from the straight tube section. The light emitting tube is formed such that a height from a corresponding sealing member to a boundary of the straight tube section and tube end section is greater than a height from the sealing member to the lower end of a radiator section of a discharge electrode and that a minimum radius of the tube end section of the light emitting tube is greater than an outer radius of the radiator section of the discharge electrode by a difference of 1.5 mm or less left therebetween.

Abstract: A high pressure metal vapor discharge lamp comprising a discharge tube disposed in an outer jacket; said discharge tube having electrodes and containing a filling comprising a starting rare gas composed primarily of xenon at a pressure from 40 to 200 Torr; means for starting said discharge tube comprising a glow starter comprising a pair of contacts spaced apart not more than 2.5 mm from each other, and containing a gas composed primarily of argon at a pressure of at least 7 Torr; the pressure in said glow starter (P.sub.g) being related to the pressure in the discharge tube (P.sub.i), according to the expression ##EQU1## and a starting electric conductor adapted to contact the discharge tube on starting thereof and to separate from the discharge tube after starting.