Abstract: An arc tube is composed of an arc tube body that is formed by winding a straight glass tube. Two portions of the straight glass tube are spirally wound around an imaginary conical surface. The spiraled portions of the glass tube are sandwiched between a pair of movable fixed plates. The spiraled portions of the glass tube are heated to a temperature equal to or higher than a point at which the glass tube is deformable and yet lower than the softening point of the glass tube. The spiraled portions are flattened by the movable plate moving downwardly under its own weight.

Abstract: An arc tube is composed of an arc tube body that is formed by winding a straight glass tube. Two portions of the straight glass tube are spirally wound around an imaginary conical surface. The spiraled portions of the glass tube are sandwiched between a pair of movable fixed plates. The spiraled portions of the glass tube are heated to a temperature equal to or higher than a point at which the glass tube is deformable and yet lower than the softening point of the glass tube. The spiraled portions are flattened by the movable plate moving downwardly under its own weight.

Abstract: An arc tube is composed of an arc tube body that is formed by winding a straight glass tube. Two portions of the straight glass tube are spirally wound around an imaginary conical surface. The spiraled portions of the glass tube are sandwiched between a pair of movable fixed plates. The spiraled portions of the glass tube are heated to a temperature equal to or higher than a point at which the glass tube is deformable and yet lower than the softening point of the glass tube. The spiraled portions are flattened by the movable plate moving downwardly under its own weight.

Abstract: A low-pressure mercury lamp has: an arc tube formed by an arc-tube body in helical configuration, and electrodes provided at respective ends of the arc-tube body; and bases supplying power to the electrodes. The arc-tube body is made of a glass tube winding around an axis A while moving into a direction of the axis A. Ends of the glass tube are positioned away from each other with the winding part therebetween in the direction of the axis A. An outer diameter of the winding part seen in the direction of the axis A is within a range of 16 mm to 38 mm.

Abstract: An arc tube is composed of an arc tube body that is formed by winding a straight glass tube. Two portions of the straight glass tube are spirally wound around an imaginary conical surface. The spiraled portions of the glass tube are sandwiched between a pair of movable fixed plates. The spiraled portions of the glass tube are heated to a temperature equal to or higher than a point at which the glass tube is deformable and yet lower than the softening point of the glass tube. The spiraled portions are flattened by the movable plate moving downwardly under its own weight.

Abstract: In a fluorescent lamp device, a discharge tube is made by arranging electrodes at the ends of a glass tube, sealing mercury and a rare gas into the glass tube and coating the inner surface of the glass tube with a phosphor, and an amalgam forming material is disposed close to one or the other of the ends of the discharge tube. This fluorescent lamp is operated with a d.c. current using as the anode the electrode arranged on the discharge tube end side where the amalgam forming material is located.

Abstract: In a fluorescent lamp of the type in which a lamp envelope comprises an outer bulb having generally a spherical or a partially spherical or a cylindrical configuration and an inner bulb inserted into the outer bulb in predetermined nested relationship; either of the inner surface of the outer bulb or the outer surface of the inner bulb is formed with a groove which defines a zig-zag discharge path between the outer and inner bulbs; a phosphor is formed at least over the wall surfaces of the groove; electrodes are disposed at the ends, respectively, of the discharge path and a uv (ultraviolet) radiation-emitting discharge gas consisting of mercury vapor and a rare gas or a rare gas mixture is filled in the discharge path, both the open end portions of the outer and inner bulbs are flared radially outwardly and inwardly respectively, or either of the open end portion of the outer or inner bulb is flared radially outwardly or inwardly so that glass frit can be filled into the annular space defined between the op

Abstract: A high-pressure sodium lamp in which the inner diameter of an arc envelope is largest at the midpoint between the ends thereof and the inner and outer diameters thereof in the vicinity of the ends at which are air-tightly fitted electrodes and their associated parts are reduced gradually relative to the inner diameter of the midpoint thereof. When the arc envelope is turned on, the following conditions are satisfied:T.sub.e .gtoreq.0.85 T.sub.c and1020.degree. C..ltoreq.T.sub.c .ltoreq.1200.degree. C.where T.sub.e is the wall temperature at the leading or inner tip of each of the electrodes andT.sub.c is the wall temperature at the midpoint of the arc envelope.

Abstract: In a fluorescent lamp of the type in which a lamp envelope comprises an outer bulb having generally a spherical or a partially spherical or a cylindrical configuration and an inner bulb inserted into the outer bulb in predetermined nested relationship; either of the inner surface of the outer bulb or the outer surface of the inner bulb is formed with a groove which defines a zig-zag discharge path between the outer and inner bulbs; a phosphor is formed at least over the wall surfaces of the groove; electrodes are disposed at the ends, respectively, of the discharge path and a uv (ultraviolet) radiation-emitting discharge gas consisting of mercury vapor and a rare gas or a rare gas mixture is filled in the discharge path, both the open end portions of the outer and inner bulbs are flared radially outwardly and inwardly respectively, or either of the open end portion of the outer or inner bulb is flared radially outwardly or inwardly so that glass frit can be filled into the annular space defined between the op

Abstract: A high-pressure sodium lamp in which the ends of an arc tube which is made of transparent single-crystal alumina and which contains sodium are sealed with feed-throughs each having an electrode extended from the inner end thereof.Each feed-through is directly sealed to the inner wall surface of each end of the arc tube. In addition, each feed-through is formed with an enlarged-diameter portion which is directly sealed to the inner wall surface at each end of the arc tube and a reduced-diameter portion which is spaced apart from the inner wall surface at each end of the arc tube.

Abstract: A high pressure sodium vapor discharge lamp,characterized in thatits discharge tube contains xenon gas at a high pressure of e.g. over 150 torr, at least one of discharge electrodes has a projection conductor which is disposed extending therefrom towards an inside surface of a side wall of a tube envelope of the discharge tube in a manner that outer end of the projection conductor is disposed in proximity to a side wall of said tube envelope with a predetermined gap in-between anda starting aid conductor is disposed lengthwise on the outside surface of the side wall, and connected to the other electrode.

Abstract: A spherical or dome-shaped fluorescent lamp comprises a spherical or dome-shaped outer bulb and an inner bulb formed with a zig-zag groove over the outer surface thereof and inserted into the outer bulb to define a zig-zag discharge path therebetween. The discharge path has a substantially circular on elliptical cross sectional configuration and is filled with a discharge medium consisting of mercury and a rare gas or rare gas mixture for emitting ultraviolet radiation. A phosphor coating is applied to the inner wall surface of the outer bulb and/or the outer surface of the inner bulb.

Abstract: The present invention disclosed the phosphor coating for fluorescent high-pressure mercury-vapor lamps, consisting of a red light emitting phosphor with the following compositionYVO.sub.4 : Eu, or (PV)O.sub.4 :Euand a blue-green light emitting phosphor with the following compositionBa.sub.1.sub.-x Mg.sub.2.sub.-y Al.sub.z O.sub.3 .sub.+ 3/2 z : Eu.sub.x, Mn.sub.ywhere 0.03 .ltoreq. x .ltoreq. 0.4, 0.01 .ltoreq. y .ltoreq. 0.6, and 12 .ltoreq. z .ltoreq. 20,A highly satisfactory color rendition may be attained, and the color temperature may be arbitrarily changed so that the mercury-vapor lamps in accordance with the present invention are best adapted for use in interior lighting in offices, lobbies, shops and so on.