| 摘要 |
<p>A low-pressure mercury vapour discharge lamp according to the invention has a discharge vessel (1, 101) which is sealed in a gastight manner and encloses a discharge space (2, 102) which contains a filling of mercury and rare gas. The discharge lamp further comprises means (3, 103) for maintaining an electric discharge in the discharge space (2, 102). A portion (5, 105) of a surface (4, 104) of the discharge vessel (1, 101) facing the discharge space (2, 102) has a reflector layer (6, 106) of aluminium oxide particles which comprise a comparatively great porportional weight of larger particles with a median diameter of 0.25 to 0.80 mu m and a comparatively small proportional weight of smaller aluminium oxide particles with a median diameter of 0.01 to 0.02 mu m, which smaller particles are present dispersed among the larger particles, while the product of the median of the overall particle size distribution and the specific surface of all particles taken together is at least 4 x 10<-><3> m<3>/kg. As a result, the lamp has a comparatively high luminous efficacy. <IMAGE> <IMAGE></p> |
