However, when it is used, the prism film light guide made by 3M company must be rolled into a cylindrical pipe with a prism film made by microcopy technique, which makes a seam at the joint of the prism films and the leak of light.

• 现有的棱镜薄膜导光管，特别是由美国3M公司生产的棱镜膜导光管是由采用微复制工艺（Microcopy）制成的棱镜薄膜卷绕而成，因而在薄膜的接头处存在着缝隙，从而在一定程度上影响了导光管的效率。