| 摘要 |
PROBLEM TO BE SOLVED: To provide a high pressure discharge lamp which has a translucent airtight container using a translucent polycrystalline ceramic having a linear transmissivity of 20% or more and in which deterioration of the linear transmissivity due to occurrence of cloudiness is suppressed, and an illumination device using the same. SOLUTION: The high pressure discharge lamp is equipped with a translucent airtight container 1 which is made of a translucent polycrystalline ceramic and has an envelope part 1a to envelope a discharge space 1c and a pair of small-diameter tube parts 1b extending from both ends in tube axis direction of the envelope part continuously integrated, and in which a linear transmissivity of the main part of the envelope part is over 20%, and a projection part 1d with its height 10-80% of the maximum inner diameter of the envelope part is formed on the inner face at lower half part in horizontal lighting of the envelope part, a pair of electrodes 2, 2, and an ionized medium filled into the translucent airtight container. COPYRIGHT: (C)2007,JPO&INPIT |
