Multi‐layer Glass Thickness Measurement

This paper focuses on the challenges that glass industry faces while conducting thickness measurement for detecting manufacturing problems and maintaining quality control at an early stage. Some of them are harsh production environments (high temperatures or caustic chemicals) and non-interruptible manufacturing processes. With multilayered glass structures, such as auto and security glass, present additional challenges in measuring individual layers are increased. In communications and consumer goods with multi-layer structures, precise thicknesses are critical to the functionality of the product. Tremendous manufacturing cost savings can be achieved by avoiding the overages that are traditionally built into these products. Thus, in order to effectively control thickness of layers during the manufacturing processes, thickness measurements should be performed in real-time during the production of the glass. Conventional mechanical metrology methods require destruction of the glass after production is done. It increases waste and adds significant cost, when a large batch of product has to be discarded because the problem was not detected in a timely manner. The interferometric method, described in this article, allows for online 100% inspection in real time.