| 摘要 |
<p>Such is especially useful as a security system and constituent element in designing coins, medals and the like, and comprises providing the surface at issue with a relief formed by a mesh of straight parallel furrows (1), the side walls (2) and (3) of which are at a given angle to the general surface plane, the said furrows being identical in size and shape, and preferably having a triangular isosceles section, in order that one of its faces or walls (2) is parallel in all, as is the case of the other (3), one of the two drawings being printed on a group of faces (2) of such ridges and the other drawing on the second group of faces (3) of such ridges, and more specifically by providing bas-reliefs (4) and (5) on such faces (2) and (3), based upon a considerably greater inclination at given areas of such faces, specifically at the areas participating in the respective drawing.</p> |
