Display addressing scheme

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

Electronic and plasma schemes: Colour displays or the pixel geometry are actually implemented using three gray-scale component system making up one pixel, and each component is followed with a primary colour-filter to separate the red, green and 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 separation of say ΔV/N volts per gray shade, where ΔV is the potential range that the pixel respons to. Each separation is typically some mV. Since there is risk for a cross-talk at neighbouring pels, the addressing scheme must carefully be designed so that addressing a pixel does not affect other neighbours. If cross-talk occures, then the contrast is reduced.

Optical scheme: The image is not pixalized at all and it is transferred from the camera or the like directly onto the LCD-screen. The image is displayed in high resolution.

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.