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US 8,013,825 B2Granted
Video system including a liquid crystal matrix display having a precharge phase with improved addressing method
AssigneeThales
InventorsHugues Lebrun, Thierry Kretz
Life of this patent
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Abstract
In a method for addressing rows and columns in a liquid crystal display, each phase for addressing rows and columns in the display includes precharging pixels of the display before a row write, to apply a precharge voltage to all pixels. Depending on the selected black or white precharge level, the light box is either switched on permanently, or is switched on during each addressing phase immediately after the precharge or immediately after the row write. The display brightness is thus improved. The display may be of sequential color type.
Claims19
A video system comprising:
- a liquid crystal display that displays a video frame including:
- a panel of pixels arranged in rows and columns, each row corresponding to a phase of a plurality of addressing phases, and at least one phase of the plurality of addressing phases in the panel being included in the video frame;
- a write rows unit configured to select the row during a row time and apply an analog voltage level corresponding to image data to be displayed, on each pixel in the selected row;
- an illumination unit, including a light box, configured to illuminate the pixels;
- and
- a precharge unit configured to precharge the pixels in the display, and to apply a precharge voltage onto all pixels, the precharge being activated in sequence at the beginning of each addressing phase before the write rows unit selects the row, and the precharge unit including a precharge circuit comprising
- a plurality of row transistors, one for each row, and a plurality of column transistors, one for each column, the row transistors and column transistors being activated simultaneously in the precharging performed by the precharge unit, the row transistors selecting all rows in the panel simultaneously, and the column transistors applying a precharge voltage to all columns simultaneously in response to the activation of the row and column transistors.
4 more elements
A video system comprising:
- a liquid crystal display comprising a panel of pixels arranged in rows and columns, a video frame including at least one addressing phase of the rows in the panel including:
- a write rows operation, containing a phase for each row to select the row during a row time and apply an analog voltage level corresponding to image data to be displayed, on each pixel in the selected row;
- an illumination operation using a light box capable of illuminating the pixels;
- and
- a precharge operation to precharge the pixels in the display, to apply a precharge voltage onto all pixels;
- wherein the precharge operation is activated in sequence at the beginning of each addressing phase before the write rows operation, and the precharge operation is achieved by a precharge circuit comprising a plurality of row transistors, one for each row, and a plurality of column transistors, one for each column, the row transistors and column transistors being activated simultaneously in the precharge operation, row transistors to select all rows in the panel simultaneously, and column transistors to apply a precharge voltage to all columns simultaneously,
- wherein the row transistors are diode-mounted.
4 more elements
Dependencies are inferred from the claim text.