High-pressure mercury lamp, lamp unit, and image display device

摘要

A high-pressure mercury lamp is provided that includes a transparent envelope made of quartz glass, in which mercury, halogen, and a rare gas are sealed and a pair of electrodes provided in the transparent envelope. The amount of the halogen sealed in the transparent envelope is in the range from 1.0x10<-6 >mumol/mm<3 >to 1.0x10<-2 >mumol/mm<3>, and 2.5 mol % to 25 mol % of oxygen with respect to the amount of the halogen is present in the transparent envelope. The high-pressure mercury lamp can prevent blackening of an inner wall of the transparent envelope from occurring over a long period of lighting without deteriorating the startability or lamp characteristics, thus achieving a long life.