Abstract: An electrodeless discharge lamp includes a lamp tube coated on inner surface with a fluorescent material and filled with mercury vapor and a rare gas where the gas provides an excitation luminescence of the same series of color as luminous color of the fluorescent material. The gas and vapor in the tube effectively maintain the luminescence of the lamp over a wide ambient temperature range where the rare gas provides luminescence of a selected color at lower temperatures and the mercury vapor and fluorescent material provide luminescence of the same color in the middle and higher temperature ranges.

Abstract: An electrodeless discharge lamp device has an envelope in which a gas that discharges to emit light upon application of a high frequency voltage is sealed, the envelope including two straight pipe parts forming a circulating discharge path, so that a high frequency electric current is caused to flow throughout the discharging gas in the entire envelope and a uniform discharge light emission can be attained.