| abstract |
A high pressure mercury lamp in which formation and spreading of milky opacification in the fused silica glass forming the discharge vessel can be advantageously prevented, and thus a rapid decrease of screen illuminance prevented, when it is used as the light source of a liquid crystal projector and the like by, in a high pressure mercury lamp in which a discharge vessel of fused silica glass contains a pair of opposed tungsten electrodes, mercury in an amount that is at least equal to 0.16 mg/mm<3>, rare gas, and at least one halogen, and in which the wall load is at least equal to 0.8 W/mm<2>, the amount of mercury added being fixed in a range from 2 x 10<-4> to 7 x 10<-3> mmole/mm<3>, and/or the at least one halogen being in the form of a carbonless halogen compound. <IMAGE> |