Sheets of stretched and polarized polymer materials and method of manufacturer

摘要

A sheet of polymer material is secured between a pair of clamping members. The sheet is directed through a localized heated region to provide a localized heated portion of said sheet. A first one of said clamping members is pulled away from the second clamping members to stretch said sheet and create from the localized heated portion of said sheet a neck-down region. The neck-down region separates providing a pair of neck-down region portions and a reduced thickness portion or stretched portion of the sheet between said neck-down region portions. One of said neck-down regions propagates along unstretched portions of the sheet as the movable clamping member moves away from the fixed clamping member while the other neck-down region remains adjacent the fixed member. This propagating neck-down region portion of the sheet is kept within the localized heated region by moving the localized heated region at a rate related to the rate which unstretched material of the sheet is fed into the neck-down region portion. While the neck-down region portion is maintained within the localized heated region, an electric field is applied to the neck-down region portion to polarize the film.