| abstract |
A variable color lamp of which the chromaticity of the light can be varied. The variable color lamp (1) has first, second, and third arc tubes (3, 4 and 5), each being a metal halide tube, in an outer tube (2). Main electrodes enclosed in the respective arc tubes are connected with a power controlling circuit (20). The first arc tube (3) in which indium halide is sealed emits light of a strong line spectrum in bluish violet. The second arc tube (4) in which thallium halide is enclosed has a strong line spectrum in green. The third arc tube (5) in which sodium halide is enclosed has a strong line spectrum in yellowish red. The color of light of the lamp can be adjusted to any color in the almost whole range of visible rays on x-y chromaticity diagram by changing the relative intensities of light of the respective arc tubes through the use of the power controlling circuit, etc. |