| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a discharge lamp, which can effectively reduce devitrification of a discharge vessel and thinning of the electrodes to significantly improve lamp life, as well as a light source and projector therewith. <P>SOLUTION: In an arc tube 10, devitrification in a swollen portion 10A can be well reduced by covering and protecting a top portion TP, which is likely to be devitrified, with a comparatively thick first protective film portion MP1 of an inner protective layer 18. In addition, a peripheral portion CP, which is likely to be blackened, is covered with a comparatively thin second protective film portion MP2. This reduces occurrence of the devitrification associated with the blackening. As a result, occurrence of the devitrification in the swollen portion 10A can be effectively reduced. Furthermore, degradation of tungsten electrodes 11a, 11a, i.e. thinning of the electrodes, caused by evaporation of boron can be reduced because the inner protective layer 18 on the peripheral portion CP has a comparatively thin form. <P>COPYRIGHT: (C)2012,JPO&INPIT |
