| 摘要 |
The sheet of fibrous material (1), e.g. paper made from cellulose fibres, containing a plastic film strip (2), has the strip made with perforations of different dimensions that give it a homogeneous porosity. The perforations are filled with the fibres, are between 100 and 1000 mcm in size and 200 to 2000 mcm apart, and can be made in a recognisable pattern, e.g. forming the letters BdF (Banque de France). The plastic strip is metallised over part of its surface, with the perforations extending into the metallised portion, and it can also carry diffractive or holographic images or a chip. |
