Programmable active matrix of electrodes

A method of operating an electrode array device comprising the steps of:

• providing an electrode array device comprising an array of unit cells that are arranged in a two-dimensional array of rows and columns;
• wherein each unit cell comprises an individual electrode element that is electrically connectable to at least one function line, and programming circuitry that is integrated into the unit cell and is operable to place the unit cell in a plurality of connection states corresponding to different states of electrical connection or disconnection to the at least one function line;
• wherein the programming circuitry comprises:
• a first storage element;
• a first electronic switch that is connected between a first function line and the first storage element;
• and
• a second electronic switch that is connected between the first storage element and the individual electrode element;
• electronically selecting one or more unit cells, and for the selected unit cells performing the steps of:
• operating the selected unit cells in a first programming mode in which the programming circuitry of the selected unit cells is charged via electrical connection to a first function line;
• wherein during the first programming mode the first electronic switch is in an on state and a current flow from the first function line through the first electronic switch charges the first storage element, and wherein the charge on the first storage element maintains the second electronic switch in an on state, whereby the unit cell is in a first connection state in which the individual electrode element is connected to the first function line;
• and;
• operating the selected unit cells in a second programming mode during which the first electronic switch is in an on state and the storage element discharges through the first function line, wherein the discharged first storage element maintains the second electronic switch in an off state, whereby the unit cell is in a second connection state in which the individual electrode element is disconnected from the first function line.