Patent ID: 8319431
Filing Date: 2012-11-27
Classification: H01J

Abstract:
1. A high intensity discharge lamp having a discharge arc tube comprising: (a) a substantially tubular ceramic member defining a discharge chamber intermediate opposite ends thereof; (b) an end plug having an opening therein for receiving an electrode/lead, wherein an end plug is disposed in each opposite end of the substantially tubular ceramic member; (c) a thermal shield extending from each end plug inwardly of the discharge chamber and defining a radial gap with the substantially tubular ceramic member; and, (d) an electrode/lead received in each end plug and having an end extending into the discharge chamber to define an arc gap therebetween, wherein the thermal shields extend inwardly from each end plug beyond the end of the respective electrode to define an axial gap therebetween significantly less than the arc gap wherein the thermal shields are operative during arc discharge to radially shield portions of the substantially tubular ceramic member from arc heat and to conduct heat axially to the end plugs.