| 摘要 |
A long-range house number identification panel has its number indicia mounte d on an illuminated viewing screen, being individually readable with the naked eye from up to 20 0 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 oil 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. An arrangement of seals preserves the integrity of the system against moisture penetration.
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