Touch screen rendering system and method of operation thereof

A method of forming a touch panel display apparatus having a user interface with which a user may interact, the method comprising acts of:

• forming first and second sheets, each having opposed major surfaces and corresponding peripheries defined by opposed ends and opposed edges, the first and second sheets each having a conductive pattern comprising a pair of opposed busbars electrically coupled to corresponding ones of the first and second sheets;
• positioning a transparent force sensing (TFS) sheet between the first and second sheet, the TFS sheet having opposed major surfaces and a variable resistance dependent on a pressure applied at a location across opposed major surfaces, wherein a change in variable resistance is logarithmically proportional to a force applied to the surface of the touch screen;
• biasing the first or second sheets apart from the TFS sheet using separation portions situated between the TFS sheet and the first or second sheet, wherein
• the sheet variable resistance, Rt, is determined by:
• Rt=(V2/V1−1)(Vx/Vcc)*Rx
• where Vcc is a predetermined voltage across a first busbar of a first conductive pattern on the first sheet and a second busbar of a second conductive pattern on the second sheet electrically coupled to the first conductive pattern via resistance Rt, V1 is a first voltage at a second busbar of the first conductive pattern, V2 is a second voltage at a first busbar of the second conductive pattern, Vx is a voltage across the first and second busbars of first conductive pattern, and Rx is a layer resistance across the first and second busbars of the first conductive pattern.