| 摘要 |
PROBLEM TO BE SOLVED: To provide a "form sheet" configured to emit light with a predetermined tone when the "form sheet" is distorted in a predetermined manner by a comparably small load, the light which is usually unrecognizable, for improving designability and forgery prevention of the "form sheet."SOLUTION: "Paper pulp fibers" and a "stress luminescent material" are mixed in a "form sheet." Distortion stress applied to the "form sheet" distorts the "paper pulp fibers" included therein and at the same time the "stress luminescent material" is also distorted. Then a predetermined stress occurs in the "stress luminescent material" to generate light of a wavelength peculiar to the "material." With this, the authenticity of the "form sheet" can be determined without any confirmation lighting device but only with visual inspection, so that the "form sheet" can achieve excellent designability and forgery prevention.SELECTED DRAWING: Figure 1 |
