| 摘要 |
1480876 Mercury-vapour lamps PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 12 March 1975 [15 March 1974] 10307/75 Heading H1D [Also in Division C4] A high or low-pressure gas-discharge lamp comprises two superposed luminescent layers, the layer nearer the discharge consisting of luminescent material which per unit weight is more expensive than the remote layer. Further, the difference between the chromaticity points of the light emitted by the two layers is less than 3À5/(1-p)CIE units, where p represents the proportion of light conversion contributed by the layer nearer the discharge. The conversion factor p must lie between 0À80 and 0À99. Several examples are given in which the remote layer consists of a certain weight of calcium or strontium halophosphate activated by antimony or manganese and the layer nearer the discharge of a smaller weight of a mixture of the three materials A, B, C: Two examples of suitable mixtures are: The invention is described as applied to a low pressure mercury vapour lamp having luminescent layers on the internal surface of the envelope. |
