A phosphor for low-pressure discharge lamps is disclosed, wherein the phosphor is present in the form of phosphor grains coated with a protective layer, wherein the protective layer consists of a metal oxide, a metal borate, a metal phosphate or mixtures thereof.

A phosphor for low-pressure discharge lamps is disclosed, wherein the phosphor is present in the form of phosphor grains coated with a protective layer, wherein the protective layer consists of a metal oxide, a metal borate, a metal phosphate or mixtures thereof.

The object of this invention is to provide a gas discharge device which has a simple configuration, inexpensive, and has excellent luminous efficiency, for an ultraviolet or visible light source.

The invention provides a gas discharge device in which first and second long electrodes extending toward either side along a longitudinal direction with a discharge gap interposed therebetween are provided outside of a back side flat surface of a thin glass tube, the thin glass tube filled with a discharge gas having a front side flat surface and the back side flat surface facing each other on a transverse section, wherein, starting with trigger discharge that is initially generated in the discharge gap as a result of a voltage increase when a voltage with a sine waveform or an inclined waveform is applied between both electrodes, the discharge gradually extends so as to move in the longitudinal direction of the electrodes. Ultraviolet light having high luminous efficiency and emission intensity is obtained from the flat surface at the front surface side by forming an ultraviolet phosphor layer in the thin glass tube and driving the device with a sine-wave voltage.

The object of this invention is to provide a gas discharge device which has a simple configuration, inexpensive, and has excellent luminous efficiency, for an ultraviolet or visible light source.

The invention provides a gas discharge device in which first and second long electrodes extending toward either side along a longitudinal direction with a discharge gap interposed therebetween are provided outside of a back side flat surface of a thin glass tube, the thin glass tube filled with a discharge gas having a front side flat surface and the back side flat surface facing each other on a transverse section, wherein, starting with trigger discharge that is initially generated in the discharge gap as a result of a voltage increase when a voltage with a sine waveform or an inclined waveform is applied between both electrodes, the discharge gradually extends so as to move in the longitudinal direction of the electrodes. Ultraviolet light having high luminous efficiency and emission intensity is obtained from the flat surface at the front surface side by forming an ultraviolet phosphor layer in the thin glass tube and driving the device with a sine-wave voltage.

Energy-saving lamps contain a gas filling of mercury vapor and argon in a gas discharge bulb. Amalgam balls are used for filling the gas discharge bulb with mercury. Novel coated balls whose operating life in the case of automatic metered introduction is increased by coating of the balls with an alloy powder and conglutination of the amalgam balls during storage and processing is prevented are proposed.

Energy-saving lamps contain a gas filling of mercury vapor and argon in a gas discharge bulb. Amalgam balls are used for filling the gas discharge bulb with mercury. Novel coated balls whose operating life in the case of automatic metered introduction is increased by coating of the balls with an alloy powder and conglutination of the amalgam balls during storage and processing is prevented are proposed.

A microwave excitation light-source device includes: a center conductor extending in an axis direction; an annular conductor having light transparency and disposed concentrically with respect to the center conductor; and an arc tube in which a luminescent material is enclosed, the arc tube being disposed so as to extend along the axis direction in an annular space created between the center conductor and the annular conductor; wherein, with respect to the arc tube, in a plane that is perpendicular to the axis direction, a single closed curve drawn along a tube wall of the arc tube intersects zero or even number of times, every line drawn from the center conductor toward the annular conductor.

A microwave excitation light-source device includes: a center conductor extending in an axis direction; an annular conductor having light transparency and disposed concentrically with respect to the center conductor; and an arc tube in which a luminescent material is enclosed, the arc tube being disposed so as to extend along the axis direction in an annular space created between the center conductor and the annular conductor; wherein, with respect to the arc tube, in a plane that is perpendicular to the axis direction, a single closed curve drawn along a tube wall of the arc tube intersects zero or even number of times, every line drawn from the center conductor toward the annular conductor.

A microwave excitation light-source device includes: a center conductor extending in an axis direction; an annular conductor having light transparency and disposed concentrically with respect to the center conductor; and an arc tube in which a luminescent material is enclosed, the arc tube being disposed so as to extend along the axis direction in an annular space created between the center conductor and the annular conductor; wherein, with respect to the arc tube, in a plane that is perpendicular to the axis direction, a single closed curve drawn along a tube wall of the arc tube intersects zero or even number of times, every line drawn from the center conductor toward the annular conductor.