Insulating window structure and method of forming the same

An improved laminate for use in making thermally insulated window panes, said laminate comprising at least two gas-impermeable transparent relatively rigid panels, and at least one plastic panel sandwiched between said rigid panels, said plastic panel having opposed planar surfaces which are bonded over substantially their entire extent to respective ones of said rigid panels, said plastic panel having a multiplicity of through perforations laterally surrounded by gas impermeable strand-like portions of said plastic panel, each of said perforations being completely isolated from the others and from ambient surroundings by said rigid panels and said strand-like portions of said plastic panel, to form a multiplicity of isolated cells within the laminate, said cells being sized so that a large stock piece of said laminate can be cut in substantially any direction to form a smaller pane with retention of at least 80% of said isolated cell structure in said smaller pane whereby thermal insulating properties of the cut pane will not be materially altered, the isolation of said cells from each other and from ambient surroundings being provided solely by said rigid panels and by said strand-like portions of said plastic panel.