Patent ID: 7982730
Filing Date: 2011-07-19
Classification: G09G

Abstract:
1. Method for power level control in a display device having a plurality of luminous elements corresponding to the pixels of an input picture, wherein the time duration of a video frame is divided into a plurality of subfields during which each luminous element can be activated for light emission in small pulses, called hereinafter sustain pulses, corresponding to a subfield code word representative of the video level of the corresponding pixel, wherein a set of power level modes is provided for subfield coding wherein to each power level mode a characteristic subfield organization belongs, the subfield organizations being variable in respect to the number of sustain pulses during a frame, and having a step for determining a power value which is characteristic for the power level of the picture to be displayed, comprising: a step for selecting a picture control value which is characteristic for the contrast and/or brightness to be applied to said picture, a transformation of the average picture power of the input picture into a first number of sustain pulses, a transformation of the selected picture control value into a maximum allowed number of sustain pulses, a minimum allowed number of sustain pulses and a sustain gain, a multiplication of the first number of sustain pulses by said sustain gain and delivering a second number of sustain pulses a selection of the maximum number of sustain pulses between said second number of sustain pulses and said minimum allowed number of sustain pulses, a selection of the minimum number of sustain pulses between said maximum number of sustain pulses and said maximum allowed number of sustain pulses and a transformation of said minimum number of sustain pulses into a power level mode and a video gain value for selecting a power level mode based on said power value and said picture control value.