HIGH PRESSURE DISCHARGE LAMP, LAMP UNIT EMPLOYING THE HIGH PRESSURE DISCHARGE LAMP, AND PROJECTION IMAGE DISPLAY EMPLOYING THE LAMP UNIT

摘要

A short arc high-pressure discharge lamp has an arc tube 1 made of quartz glass including a light-emitting portion 2 that fills mercury inside thereof and has a pair of electrodes arranged so as to face each other, and a sealing portion 3 connected to the light-emitting portion. The pair of electrodes have an electrode bar 5a, one end of the electrode bar is located in an internal space of the light-emitting portion, and the other end of the electrode bar is embedded in the sealing portion and bonded to a conductive metal-foil 7 sealed in the sealing portion. In at least a part of a portion of the electrode bar embedded in the sealing portion, the entire outer peripheral surface thereof is covered tightly with a metal-foil sleeve 7a. A high efficiency and high quality lamp is obtained in which fracture in the sealing portion of the arc tube caused by an ultrahigh vapor pressure in the tube surely is suppressed over the lifetime of the lamp, and the vapor pressure in the arc tube is elevated up to 30 MPa or more.