A method and apparatus for filling a via with transparent material is presented, including the steps of providing a panel having a via, occluding the via with transparent material in a workable state so that a portion of the occluding material is internal to the via and a portion of the material is external...http://www.google.com/patents/US7943862?utm_source=gb-gplus-sharePatent US7943862 - Method and apparatus for optically transparent via filling
