Resistive bridges can connect many ring electrodes in an electro-active lens with a relatively small number of buss lines. These resistors are usually large to prevent excessive current consumption. Conventionally, they are disposed in the same plane as the ring electrodes, which means that the ring electrodes are spaced farther apart or made discontinuous to accommodate the resistors. But spacing the ring electrodes farther apart or making them discontinuous degrades the lens's optical quality. Placing the ring electrodes and resistors on layers separated by an insulator makes it possible for the ring electrodes to be closer together and continuous with resistance high enough to limit current consumption. It also relaxes constraints on feature sizes and placement during the process used to make the lens. And because the resistors and electrodes are on different planes, they can be formed of materials with different resistivities.
