Passive matrix addressing

Passive matrix addressing is an addressing scheme practioned in displays, or at least a future displays. The signal is divided into a row or select signal and a column or video signal. Given a n×m matrix, the number of connectors needed is (n + m) ones. This is drastically less that the number of pads needed in active matrix addressing. The select voltage determinates the row that is beeing addressed and all m pixels on a row is addressed simultaneously. When pixels on a row are beeing addressed, a V_sel potential is applied, and all other rows are unselected with a V_unsel potential. The videosignal or column potential is then applied with a potential for each m columns individually. An on-lighted pixel corresponds to a V_on, an off-switched corresponds to a V_off potential.

The potential across pixel at selected row i and column j is

$V_{ij}=V_{sel}-V_{on|off}$

and

$V_{ij}=V_{unsel}-V_{on|off}$

for the unselected rows. The figure below illustrates a 3×3-matrix display.

sketch figure finished

See also: active matrix addressing, pixel geometry, LCD