Patent ID: 7423619
Filing Date: 2008-09-09
Classification: G09G

Abstract:
1. An array of pixels, each pixel comprising: a pixel element, each pixel element comprising a first pixel electrode for individual control of the pixel element and a second pixel electrode, the second pixel electrode linking substantially all pixel elements in the array and being connected to a common counter-electrode, the first and second pixel electrode forming a first capacitor, the pixel element having a threshold voltage and a modulation voltage, a pixel refresh circuit, for transferring electric charge related to a pixel data value from a data input of the pixel to the first pixel electrode via a charge transfer path, a first memory element coupled to the pixel data input for storing electric charge related to the pixel data value, a first switch element located between the first memory element and the first pixel electrode for controlling charge transfer from the first memory element through the charge transfer path to the first pixel electrode, wherein the first switch element and the first memory element co-operate to transfer charge related to the pixel data value passively along the charge transfer path to the first capacitor and wherein the array further comprises means for applying a dynamically changing voltage to the common counter-electrode, the dynamically changing voltage changing between minus the threshold voltage of the pixel elements and the sum of the threshold voltage and the modulation voltage of the pixel elements so that the pixel data value is a signal comprised between zero volts and a data voltage value, the data voltage value being not smaller than the modulation voltage and smaller than the sum of the modulation voltage and the threshold voltage of any of the pixel elements.