A method of forming a pixel for a liquid crystal display includes forming a pixel electrode on a substrate, depositing a continuous three layer amorphous silicon alloy structure with an intrinsic layer between two n-doped layers, depositing an opaque metal layer over the semiconductor layers and etching the top metal layer and semiconductor layers to form continuous address lines with underlying semiconductor layers and a bidirectional threshold element connected between each electrode and an adjacent overlying address line. A metal pad positioned on each electrode provides for improved conductivity with each adjacent threshold element. The threshold elements have a threshold settable by directing light through each pad, provided the pads are at least partly transmissive. A symmetrical bilateral threshold element is formed of first and second series coupled threshold elements.