Electrodeless high intensity discharge lamp.

摘要

An electrodeless high intensity discharge lamp (10) has a light transmissive ceramic arc tube (18) for containing a discharge sustaining medium and a hollow tube member (24). An excitation coil (14) for causing an arc discharge is situated about the arc tube (18). The ceramic arc tube (18) includes a first portion (18a) for developing the arc discharge therein and a second portion (18b) protrouding outwardly from the first portion (18a). The hollow tube member (24) is so disposed in the second portion (18b) that a space (30) is provided between the inner wall surface of the second portion (18b) and the outer wall surface of the hollow tube member (24). The space (30) is communicated with the interior of the first portion (18a) for allowing the medium to be condensed and retained during the lamp operation.