| 摘要 |
<p>The membrane (4, 20), which has a synthetic material layer, is comprised of several layers. It is proposed to use a metal sheet (aluminium sheet 10) inserted between synthetic material layers (11, 12). The synthetic material layers are produced by vacuum metallization. It is also proposed to provide at least three synthetic material layers (21, 22, 23). Preferably, the synthetic material layers (21, 22, 23) are made of the same material and have a different hardness. </p> |
