| 摘要 |
A container/preform (1) of mainly plastic material comprises several layers (10-12) wherein at least in one layer (11) are present one or more substances and/or material which bring about that the layer reflects light invisible to the eye, e.g. UV-light. Owing to this it is possible to measure the extension and/or layer thickness of the layer (11) by determining the ranges where the incident light is reflected or the intensity of the reflected light. The invention is particularly suitable for transparent containers/preforms and makes it possible to check the production without destroying the containers/preforms which are manufactured. |
