Patent ID: 7859493

Claim:
Active matrix display panel, comprising a substrate, an array of pixel circuits being arranged in a matrix of at least one column and a plurality of rows on the substrate, each pixel circuit comprising a light-emitting element, capable of emitting light of an intensity determined by the value of a current passed through it, and at least N column lines for each column of pixel circuits, N being larger than one, each column line arranged to conduct a reference current, provided by a current driving circuit, when connected to the panel, wherein the pixel circuits in a column are divided into a plurality of groups of at least one pixel circuit, wherein the active matrix display panel comprises at least one current mirror circuit associated with a first group, comprising a first current mirror, arranged to mirror a reference current flowing through a column line to a first current mirror output, wherein each pixel circuit in the first group comprises at least a first current-memory stage, having an output terminal connected to the light-emitting element, wherein the first current-memory stage is capable of drawing a current determined at least partly by the current mirrored to the first current mirror output through the output terminal, wherein each current mirror circuit comprises at least one additional current mirror, arranged to mirror a reference current flowing through an associated column line to an additional current mirror output, and wherein each additional current mirror output is connected in parallel to the first current mirror output, wherein the current mirror circuit comprises at least N current mirrors, each arranged to mirror a reference current flowing through an associated one of the column lines to a current mirror output of the current mirror, and an adder for adding currents flowing through the current mirror outputs.