Patent ID: 8048250
Filing Date: 2011-11-01
Classification: B29C,F24S,G02B,H01L,Y02E,Y10T

Abstract:
1. A method of manufacturing a photovoltaic (PV) enhancement film, comprising: providing an extrusion device comprising an embossing roller with a surface engraved with a contoured pattern corresponding to a plurality of absorption enhancement structures; feeding a web of substantially transparent material at an extrusion temperature to the extrusion device; and rolling the embossing roller against a first side of the web to form the plurality of absorption enhancement structures, wherein the absorption enhancement structures each comprise a light receiving surface that directs at least a portion of light that passes through a second side of the web toward the first side back toward the second side, wherein each of the absorption enhancement structures comprises an elongated body including at least two sides angled inward, whereby the absorption enhancement structures extend outward from the web of substantially transparent material, wherein the elongated bodies extend across the first side of the web in a parallel manner and adjacent ones of the bodies have spaced apart facets that together with pairs of the adjacent sides define a space substantially free of the substantially transparent material, wherein, when the embossed web is applied over a layer of PV material with the absorption enhancement structures facing away from the layer of PV material, the light receiving surface refracts incident light striking the first side to provide an average path length ratio of greater than about 1.10 within the PV material layer over a range of incidence angles as determined based on a first pass of the refracted incident light traveling through the PV material layer, and wherein the absorption enhancement structures comprise two sets of differing configurations, a first one of the configurations having a triangular cross section with a base of less than about 13 mils and a height of less than about 7 mils and a second one of the configurations having a triangular cross section with a base of less than about 13 mils and a height greater than the height of the first one of the configurations and less than about 10 mils.