Abstract: A high intensity discharge lamp has an arc tube, which is filled with substances for gas discharge. The arc tube includes a bulbous portion. Surrounding the arc tube there is a tubular envelope. The envelope has an enlarged portion, which is similar to the bulbous portion. The distance between the envelope and the outer wall of the arc tube is uniform thereby resulting in uniform temperature distribution on the wall of the arc tube, improved thermal stability, improved luminous and electrical parameters. The lamp reduces the light refraction which occurs between the inner surface of the envelope and the outer surface of the arc tube and also between the two interface of the envelope wall thereby emitting more light and reducing the occurrence of glare.

Abstract: The present invention disclosed a high-intensity discharge lamp without or with low mercury, including the metallic halide discharge lamp, the high pressure mercury lamp and the mercury-xenon lamp and so on. When the high-intensity discharge lamp without or with low mercury according to the invention is used, the optimum amount of Se or HgSe is determined based on the type and the power of the lamps to substitute for the mercury partially or completely. Thus a proper light spectrum can be reached with a high color rendering index (for example 95). The mercury packed in the high-intensity discharge lamp without or with low mercury according to the invention can be substituted completely or reduced greatly. The lamp meets the requirement of the environmental protection and is a potential new-style light source.

Abstract: The invention provides a high intensity discharge lamp with a lamp cap, which has a simple and firm structure, higher thermal stability, lower glare and higher efficiency. The discharge lamp comprises an arc tube, which is filled with substances for gas discharge. The arc tube comprises a bulbous or ellipsoidal portion. Surrounding the arc tube is a tubular envelope; the envelope has an enlarged portion, which is similar to the bulbous or ellipsoidal portion disposed of the bulbous portion of the arc tube. The distance between the envelope and the outer wall of the arc tube is uniform; it makes the temperature distribution on the wall of arc tube more uniform, then the thermal stability, the luminous and electricity parameters of the lamp are improved.