Integrated method of detecting an image defect in a liquid crystal screen
AssigneeThales
InventorsHugues Lebrun, Gérard Voisin
Life of this patent
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Abstract
An integrated method of detecting an image defect in an LCD screen consists in verifying the consumption of current on a power supply bus of the image display means (row driver 20, column driver 30, counter electrode CE), during capacitive charges or discharges of the selection lines Li and/or columns ColRj. The method comprises the integration of a current measurement chain comprising a measurement resistor Rm on the power supply bus and measurement 41 and comparison 42 circuits providing outside the screen a detection signal Sd which is processed by an external circuit for safety management.
Claims10
An integrated method for a detection of a display defect of an image in an LCD screen comprising pixel electrodes arranged in matrix fashion in data lines and selection lines, a common counter-electrode and image display means piloted by a video signal, the method comprising:
- applying control voltage levels to said pixel electrodes via said data lines and said selection lines and to the common counter-electrode, wherein said video signal, the image display means, the selection lines, the data lines and the pixel electrodes form an image display control video chain;
- verifying an integrity of said image display control video chain, wherein verifying the integrity of said image display video chain comprises measuring a signal representative of current inrushes during capacitive charges or discharges of the data lines and/or the selection lines of the LCD screen by means of activating a current measurement chain of a consumption of current on at least one power supply bus of said image display means, wherein the current consumption measurement chain outputs a corresponding digital measurement signal;
- wherein said at least one power supply bus is a power supply bus of a control circuit of the selection lines for selecting rows of image elements of said LCD screen, and activated at each new display window of a video image, and deactivated or disabled between two display windows.
An integrated method for a detection of a display defect of an image in an LCD screen comprising pixel electrodes arranged in matrix fashion in data lines and selection lines, a common counter-electrode and image display means piloted by a video signal, the method comprising:
- applying control voltage levels to said pixel electrodes via said data lines and said selection lines and to the common counter-electrode, wherein said video signal, the image display means, the selection lines, the data lines and the pixel electrodes form an image display control video chain;
- verifying an integrity of said image display control video chain, by means of detecting a consumption of current on at least one power supply bus of said image display means during capacitive charges or discharges of the data lines and/or the selection lines of the LCD screen;
- and
- wherein said at least one power supply bus is a power supply bus of a control circuit of the data lines associated with the image display means of said LCD screen, and/or to a power supply bus of the common counter-electrode, and activated in a period between two display windows of a video image and deactivated during each of the two display windows of the video image.
Dependencies are inferred from the claim text.