| 摘要 |
A long-range house number identification panel has its number indicia mounted on an illuminated viewing screen, being individually readable with the naked eye from up to 200 feet distance. An electrically energizable phosphorescent screen behind the indicia serves to illuminate the numbers at night. The identifying indicia may consist of transparencies through the surface of a blanking screen. A photocell switches off the screen in daylight; and the level of screen illumination may be limited below the optimum, by operating at a reduced voltage so as to extend the service life of the screen. A u/v barrier coat may be used to protect the phosphor of the screen against solar degradation.
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