Flashing microtext that, when viewed with the unaided eye, appears to be part of the line design, bet under magnification is seen as a repeated pattern of words, codes or numbers.
通过
用

字,来增加防伪特征。闪烁的

字,
没有
用放大镜的情况下,看到的只是一条线,

用放大镜观看时,可以看到连续重复的
字、编码及数字等。
速英语_科技
。
历史趣谈
课堂

测算而非观测发
,古代监测者并没有发


