High intensity discharge lamps.

摘要

The arc tube filling comprises the usual inert, ionizable starting gas and mercury in predetermined amount. The metal halide filling substantially comprises a predetermined limited amount of thallous iodide, a predetermined limited amount of stannous iodide and a predetermined limited amount of calcium iodide. The stannous iodide serves primarily to enhance the emission of the calcium iodide and the amount of stannous iodide is sufficiently limited to curtail the generation of the characteristic continuous tin emission. The calcium iodide is present in greater gram amount than the tin ioaide so that the effects of the calcium iodide emission are predominant. The resulting discharge has its emission concentrated in three selected wavelength portions of the visible spectrum, namely blue violet which is due primarily to the calcium iodide emission, green which is due to the thallium iodide emission, and red which is due to the tin-iodide-enhanced calcium iodide emission.