| 摘要 |
<p>PURPOSE:To provide a hidden image in which first and second areas are scarcely identified with the naked eye on a sheet before copying and, in the case of copying, both the areas can be effectively identified on the copy sheet. CONSTITUTION:The hidden image comprises a character part formed by disposing many first patterns 11 and a background part formed by disposing many second patterns 13. The patterns 11 and 13 are respectively formed of two lateral linear elements 15 in such a manner that the interval L1 of both the elements 15 of the pattern 11 is different in size from that of both the elements 15 of the pattern 13. Further, in the image so formed that the sums of the areas of the elements 15 of the patterns 11 and 13 are equal, it is so formed that the sum of the lengths of line segments for connecting the outer peripheries of the elements 15 of the pattern 11 becomes equal to that of the lengths of line segments for connecting the outer peripheries of the elements 15 the pattern 13.</p> |
