| 摘要 |
PROBLEM TO BE SOLVED: To provide a phosphor film not disturbing display on the rear side even if being arranged on the front side in a fluorescent character display device duplicately displaying two display parts. SOLUTION: A first luminous part 7 is arranged on the back side and a second luminous part 10 is arranged on the front side on the facing inside surfaces of an envelope 1. The second luminous part 10 is formed by installing the phosphor film 9 on the inner surface of a transparent conductive film 8. The phosphor film is prepared in the following processes; a sol-like phosphor raw material solution containing SrTiO3: Pr and Al is applied onto the transparent conductive film 9 of a substrate 3, and the substrate is baked at 500 deg.C in the atmosphere. Thereby, the almost transparent, crystallized phosphor film 9 is formed on the substrate. Transmission factors every wave length of transmitted light of three substrates of the substrate 3 having the phosphor films 9, a substrate having the existing phosphor layer, and the substrate itself are illustrate. The figure shows that the existing phosphor layer decreases the transmission factor by 10% or more compared with only the substrate, but the phosphor film 9 rarely decreases the transmission factor.
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