| 摘要 |
<p>An electric lamp having a luminescent layer (17) on the lamp envelope (3) which produces visible light when impinged by ultraviolet radiation generated within the lamp. An undercoat for the luminescent layer (17) increases the luminous efficacy of the lamp. The undercoat comprises an agglomerated particulate material of predominantly gamma alumina having a primary crystallite size of less than about 0.05 νm. The undercoat is effective to increase the luminous efficacy of certain fluorescent lamps so that they meet the minimum efficacy requirements of the Energy Policy Act of 1992.</p> |
