Display addressing scheme

There are three different addressing schemes for display-devices; 1) electronically or 2) optically addressed displays, or 3) addressing by plasma columns. Each teqnique allows a physical way of switching the pixel to a black-white or more usually gray-scale state.

Colour displays or the pixel geometry are actually implemented using three gray-scale components making up one pixel and component corresponding to a primary colour red, green or blue. So the treatment simplifies since it is sufficient to consider only a pixel with N gray shades. The shade level is typically lineary dependent on the applied potential over the pixel, so each level will translate into a gap of say δV/N volts per gray shade. Since there is risk for a cross-talk, the addressing scheme must carefully be designed so that addressing a pixel does not affect other neighbours.

Electronically addressing

There is three kinds of electronically addressing schemes for Liquid Crystal Displays (LCD). Direct addressed display include a conductor to each pixel, and thus, for a n×m-display, (n×m) pads are needed. Active and Passive matrix addressing wire the conductors in a matrix. The former needs to connect one Thin Film Transistors (TFT) to each pixel, and the latter relies on the pixel's bistabilty such as ferroelectrism. For a n×m-matrix schemes, only (n + m) pads are needed.