Patent ID: 6414436
Filing Date: 2002-07-02
Classification: H01J

Abstract:
In an optical projection system, a high intensity discharge lamp for producing uv or visible light and having an anode electrode and a cathode electrode, wherein an effective correlated color temperature is maintained of continuous non-flash operation thereby increasing the efficacy of the lamp radiation output comprising:(a) a lamp bulb envelope tube of single crystal (SC) sapphire tubing, having a tubular burst pressure of at least 155,000 psi at 25Â° C.; (b) wherein the lamp bulb envelope is cylindrical in shape with an inner diameter of between 1 mm and 25 mm and an outer diameter D of 2 mm or more; and (c) a fill in said envelope which emits uv or visible light radiation, having a color temperature between 6500 and 7000 degrees Kelvin, when an arc is struck between the electrodes and whose fill pressure exceeds 120 atmospheres.