| 摘要 |
An engraved plate for intaglio printing or embossing of sheets of security papers, comprising a plate portion generating on each said security paper a control element, said portion being provided with at least one first set of asymmetrical furrow elements, each said furrow element having a first side wall and an opposite second side wall, the average slope of said first side wall being different from the average slope of said second side wall, and the slopes of said first side walls of said set of furrow elements being substantially equal amongst themselves and the slopes of second side walls of said set of furrow elements being substantially equal amongst themselves. |
