| 摘要 |
PROBLEM TO BE SOLVED: To prevent the visibility of a sign by providing display plates reacting to ultraviolet rays and visible lights in pattern and ground parts of a sign plate, setting a response degree of the pattern part to ultraviolet rays and visible lights higher than that of the ground part and illuminating the display surfaces by mixed lights between ultraviolet rays and visible lights from a floodlight. SOLUTION: A pattern part 12 and a ground part 13 are formed in a sigh plate 11 supported by a strut 10. The pattern and ground parts 12 and 13 are formed to have display surfaces reacting ultraviolet rays and visible lights by coating these with phosphors or disposing phosphorus sheets. The response degree of the pattern part 12 to ultraviolet rays and visible lights is set higher than that of the ground part 13. The display surfaces are illuminated by lights mixing ultraviolet rays of wavelength regions 315nm to 400nm and visible lights of wavelength regions 400nm to 700nm from a floodlight main body 1. Thus, the visibility of the sign plate from a far distance is increased, characters and patterns are clearly viewed and visibility under such bad conditions as fogs, snow storms and a dark period is increased. |
