| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-priced display device capable of arousing a person's interest in it by providing a part to receive visible rays and display them and together with a part to receive near ultraviolet rays and display them by firefly luminescence on the display surface of a display device. SOLUTION: Separately from ordinary liminaire, near ultraviolet ray 6 alias black light is provided on a display plate 1. In this black light, there is a fluorescent lamp type, a mercury lamp type, and the like. In this case, the target of the light of the black light is set to be a special fluorescent material layer 5. Considering output of the black light, the distance to the display plate, and the light generation brightness characteristic of the special fluorescent material layer 5, the light generation brightness of the special fluorescent material layer 5 is set so as to be at least 2.5 cd/m2. In this case, illuminance of the ordinary light on the special fluorescent material layer 5 is set so as to be 50-500 lux. Hereby, at night, figures, letters, or the like constituted by the special fluorescent material layer 5 appear or disappear on the display surface.
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