US Patent 7973311 Isolated sensor structures such as for flexible substrates

A photosensor structure includes a pixel metal layer disposed in physical and electrical contact with a pixel thin film transistor and a lower sensor layer of a p-i-n photosensor. The pixel metal layer extends laterally to an extent less that the lower sensor layer such that an overhang region is defined below the lower sensor layer and the adjacent the lateral edge of the pixel metal layer. When the relatively thick intrinsic sensor layer is formed over the lower sensor layer, it attaches to the upper surface and, due to the presence of the overhang region, the lateral edge of the lower sensor layer, forming a discrete intrinsic sensor layer structure over the pixel which is physically isolated from adjacent corresponding structures. This isolation allows for thermal expansion and contraction during formation of the intrinsic sensor layer without cracking the intrinsic sensor layer structure.