HIGH-PRESSURE DISCHARGE LAMP, ELECTRODE FOR HIGH- PRESSURE DISCHARGE LAMP, MANUFACTURE OF ELECTRODE FOR HIGH-PRESSURE DISCHARGE LAMP, AND LIGHTING OPTICAL DEVICE AND IMAGE DISPLAY DEVICE USING HIGH-PRESSURE DISCHARGE LAMP

摘要

PROBLEM TO BE SOLVED: To obtain a high-pressure discharge lamp allowing suppression of a blackening phenomenon. SOLUTION: This high-pressure discharge lamp has a pair of electrodes 14 within a light emission tube. The electrode 14 has an electrode shaft 141, and a coil 142 wound around a tip part of the electrode shaft 141. The coil 142 is fixed to the electrode shaft 141 such that both discharge side tip parts of the electrode shaft 141 and the coil 142 are melted and integrated when a first discharge occurs. Specifically, the coil 142 is wound around the periphery of the electrode shaft 141 such that the discharge side tip of the electrode shaft 141 projects from the discharge side tip of the coil 142 by a length L (mm) satisfying the relation 1/50*R3=L=1/5*R3 wherein a maximum external diameter of the discharge side tip part of the coil 142 is R3 (mm).