Abstract: The manufacture of an electrodeless bulb involves one end of a tube closed off, and a first neck is formed in the tube close to the closed end. A second neck is formed in the tube, close to the still open end; a metal halide pellet of known size is dropped into the tube and the tube is evacuated. With the vacuum being maintained heat is applied to the closed end, causing the metal halide pellet to sublime and with it the impurities. The impurities are drawn off, the vacuum being maintained and the metal halide condenses in the tube between the necks. Once the tube is cool, the evacuation is discontinued and the tube is refilled with noble gas and the quartz tube is sealed off at the second neck.

Abstract: The manufacture of an electrodeless bulb involves one end of a tube closed off, and a first neck is formed in the tube close to the closed end. A second neck is formed in the tube, close to the still open end; a metal halide pellet of known size is dropped into the tube and the tube is evacuated. With the vacuum being maintained heat is applied to the closed end, causing the metal halide pellet to sublime and with it the impurities. The impurities are drawn off, the vacuum being maintained and the metal halide condenses in the tube between the necks. Once the tube is cool, the evacuation is discontinued and the tube is refilled with noble gas and the quartz tube is sealed off at the second neck.

Abstract: A method of making an electrodeless incandescent bulb comprises the steps of: providing a bulb tube of quartz glass, closing one end of the bulb tube, forming a neck having a bore less than the internal diameter of the bulb tube, inserting a pellet of excitable material into the bulb tube through the adjacent neck, evacuating the bulb tube through the neck and sealing the bulb.

Abstract: A method of making an electrodeless incandescent bulb comprises the steps of: providing a bulb tube of quartz glass, closing one end of the bulb tube, forming a neck having a bore less than the internal diameter of the bulb tube, inserting a pellet of excitable material into the bulb tube through the adjacent neck, evacuating the bulb tube through the neck and sealing the bulb.

Abstract: A discharge units comprises a transparent envelope filled with a discharge gas containing mercury, and electrodes for exciting the gases by applying an electric field. It has been found that if, apart from the mercury vapour, the gas is about 99% argon and of the order of 0.1-1% krypton then the proportion of near-visible UV lines is increased, in relation to the 254-nm line, particularly if pulsed excitation is used. This increases the efficiency of the lamp when used to excite visible phosphors.

Abstract: An apparatus and method for applying short pulsed waveforms, on the order of 1 &mgr;s pulses at a frequency of about 5 kHz, to a discharge lamp, such as a low-pressure mercury/argon lamp, in order to shift the ratio of the intensities of two of the mercury lines, in particular the 254 nm and 365 nm lines, of which for a sinusoidal excitation signal the 254 nm line is predominant, towards the higher wavelength. This greatly increases the efficiency of a lamp using phosphors excited by these UV emissions, because of the reduced Stokes shift.