| 摘要 |
A metal halide arc discharge lamp is disclosed having a power input rating of not more than 35 watts. The lamp comprises an envelope of light transmissive material, such as fused quartz, including a bulb portion (26), a pair of transitional neck portions (24, 24') extending from the bulb portion (26), and a pair of stem portions (22, 22') extending from the transitional neck portions (24, 24') respectively. The bulb portion (26) of the envelope defines an arc chamber (28) therein and has an external surface area of such value as to produce a wall loading not exceeding 35 watts /cm2. The arc chamber (28) contains a fill of mercury, inert gas and metal halide. The mercury and the metal halide are adapted to substantially vaporize during operation of the lamp. A pair of electrodes (30, 30') extend into the arc chamber (28) from the pair of neck'portions (24, 24') respectively. Each electrode has an electrode tip spaced apart from one another by a distance A (FIG. 2) within the arc chamber (28). The neck portions (24, 24') of the envelope each have a wall surrounding a segment of one of the electrodes (30, 30'). The walls of the neck portions (24, 24') each have a stretched section with a minimum wall thickness not exceeding about 1.5 mm. A pair of inlead assemblies are electrically coupled to the pair of electrodes (30, 30') respectively. The inlead assemblies pass from the electrodes (30, 30') through a hermetically sealed section in the stem portions (22, 22') of the envelope to the exterior of the lamp.
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