Thomson Licensing

Thomson Plasma

Dominique Gagnot

Ana Lacoste

Philippe Le Roy

Laurent Tessier

Gérard Rilly

Pierrick Martin

Pascal Denoyelle

A video display device comprises a plurality of light emitting elements arranged in a matrix having rows and columns; a plurality of first current modulators each of which is associated to one of said light emitting elements for drawing a feed current of programmable intensity for the associated light emitting element from a circuit node associated to each of said columns; a current generator controlled by video data representative of desired luminosities of said light emitting elements for supplying a first current (I)to said circuit node, the intensity of which is representative of a desired luminosity of at least one of said light emitting elements; the circuit node having a specific voltage level when the intensity supplied by said current generator is drawn from the current node by the first current modulator associated to said at least one light emitting element; a second current modulator for supplying a second current (I) to said circuit node; a comparator having inputs connected to said circuit node and to a reference terminal which is constantly held at said specific voltage level and an output connected to a control input of said second current modulator, whereby the second current (I) from said second current modulator is controlled so as to yield said specific voltage level at the circuit node.

Video display device and operating method therefore

Method comprising a succession of image frames which each comprise a sustain phase of the display discharge regions which itself comprises the application of sustain voltage pulses Vbetween the electrodes of each pair crossing these regions, and, during each sustain pulse, the application of trigger voltage pulses Vto groups of discharge regions, which pulses are applied successively and not simultaneously to the various groups of discharge regions. Thanks to the application in stages of the trigger pulses during each sustain pulse, a reduction in the instantaneous current required to supply the display is obtained.

Method for driving a plasma display with matrix triggering in stages

The method of the invention generates an address signal for addressing columns or rows of a PDP. In the case of addressing a column, for example, the method comprises the following steps. For a phase T, a DC voltage Vis applied across the terminals of a solenoid L, so that the latter stores energy, and applies a voltage A across the terminals of a selected column. During a phase T, some of the energy stored in the solenoid L is discharged into the column until the voltage across the terminals of the column becomes about zero. During a phase T, an approximately zero voltage is maintained across the terminals of the column. According to one embodiment the selection of the column(s) during this phase is modifiable. During a phase T, the solenoid L is charged with current stored in a capacitor until the voltage across the terminals of the column is zero.

Method of generating an address signal in a plasma panel and device for implementing said method

A method for driving a plasma display having discharge regions each crossed by a pair of sustain electrodes (Y, Y) and at least one trigger electrode (X) is disclosed. The method includes a succession of image frames or subframes which each have a discharge region sustain phase including the application of voltage pulses Vbetween the electrodes of each pair of sustain electrodes serving these regions, and the application of a trigger pulse V, of duration &#x3c4;less than 1 &#x3bc;S, between the trigger electrode (X) and one and/or the other of the electrodes of each pair serving these regions. The intensity and luminous efficiency of plasma displays can thus be significantly improved.

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Charavines, France

Dominique Gagnot