THREAD-INSERTED PAPER HAVING PROPER PAPER CROSSSECTIONAL SHAPE AND METHOD FOR AUTHENTICITY DISCRIMINATION OF THE THREAD-INSERTED PAPER

PROBLEM TO BE SOLVED: To rapidly and surely discriminate authenticity of thread inserted paper by utilizing remarkable difference of physical shape of paper cross section. SOLUTION: The method for discriminating authenticity of paper by taking advantage of remarkable difference of crosssectional structure among paper (a) produced by a method for applying tension to a thread 1 by a long net, paper (b) produced by a method for not applying tension to a thread by a long net or a method for inserting a thread into a single layer paper by a round net and paper (c) produced by a method for inserting a thread between two layers of two-layer paper by a round net comprises cutting each paper by a focused ion beam, making the cut cross section of the paper (a) real and that of the paper (b) or the paper (c) false, comparing the crosssectional image of paper of a test target by electron microscope observation with that of real paper. When both the observed images are coincident, the paper of the test target is judged as real paper and when they are not coincident, the paper of the test target is judged as false paper. COPYRIGHT: (C)2005,JPO&NCIPI