1.前言薄和软的材料,比如聚脂薄膜、磁带或光盘片基和箔的厚度测量提出一些特殊问题。很多厚度直接测量法苦于灵敏度不够和不能重复。为抵止不准确的测量系统,许多制造厂采用了间接测量法,比如通过称量产品的重量来控制总的投料厚度。不幸的是用这种方法是不可能了解产品每个点上的厚度均匀问题。 1. Introduction Thickness measurements of thin and soft materials such as mylar, tape or disc bases and foils pose particular problems. Many methods of direct thickness measurement suffer from insufficient sensitivity and can not be repeated. To combat inaccurate measurement systems, many manufacturers use indirect measurements, such as controlling the total charge thickness by weighing the product. Unfortunately with this method it is impossible to know the uniformity of thickness at each point of the product.