Thomson-csf

Thomson Multimedia S.a.

Thomson Tubes Electroniques

Thomson Licensing

Philippe Zorzan

Eric Benoit

Serge Salavin

Michel Specty

Gérard Rilly

Andr&eacute; Dunand

The present invention relates to a device for driving a plasma display panel having a plurality of cells arranged in rows and columns, said device comprising row address means for selectively addressing the display cell rows and creating, where required, in cooperation with means for selectively applying data voltages to the display columns, an electrical discharge inside the cell disposed at the intersection of the row and column selected during an address phase, and sustain means (I, I, I, I) for sustaining the electrical discharges inside said cell during a sustain phase immediately following the address phase. According to the invention, the row address means and/or the sustain means are capable of allowing a bi-directional current to flow in the display cells during the address and/or sustain phases. The capacitive and light-emission currents appearing during these phases can thus flow freely and do not create electromagnetic interference.

Device for driving a plasma display panel

A control process for addressing an AC plasma panel. The panel includes line electrodes crossed with column electrodes where the intersections of these electrodes define cells. Sustain signals are applied to all of the line electrodes by way of at least one control circuit. The cells are addressed by superimposing supplementary voltage porches onto the sustain signals and then subsequently superimposing addresses pulses onto the supplementary porches. This method makes it possible to reduce the amplitude of the addressing pulses, thus resulting in a lesser demand on the control circuits resulting in a reduction of capacitive consumption.

Method for controlling the addressing of an AC plasma display panel

A method for activating the cells of an image display screen. Electric potential signals called activation signals are produced to activate the cells and to supply the current consumed by this activation. An electric potential is applied to a solenoid so as to develop the activation signals at the solenoid terminals and to cause a change in the main current in the solenoid which serves as the current consumed by the cell activation. Thus, cell activation control of the &ldquo;current supply&rdquo; type is effected, and is particularly suited for the delivery of large amounts of current in a short time. This may be used in image display screens such as plasma panels.

Method for activating the cells of an image displaying screen, and image displaying device using same

In a method for adjusting the overall luminosity of at least a part of a matrix screen, each row of the part is processed several times non-periodically to display half-tones. Each processing consists of a semi-selective operation followed by a selective operation. A delay is planned between the selective operation and the semi-selective operation, this delay being proportional to a weighting factor that is adjustable as a function of the desired overall luminosity and proportional to the time interval between the beginning of the treatment in progress and the beginning of the next treatment.

Method for adjusting the overall luminosity of a bistable matrix screen displaying half-tones

Disclosed are a method for the control of an image display screen displaying half-tones and a display device implementing this method. The disclosed method is used to control an image display screen of the type having cells arranged in rows and columns and working either in a state known as an 'OFF' state or in a state known as an 'ON' state in which they are activated and produce light. The method consists in activating the cells of each row during sub-periods of different duration, with orders of distribution of the sub-periods that are different between two successive rows. This results in a reduction of the amplitude of the variations of a load constituted by the cells in the &lt;&lt;lit&gt;&gt; state of these two consecutive rows. Application inter alia to alternating plasma panels.

Method for the control of an image display screen displaying half-tones

A method for the control of a display screen whose pixels are cells producing light is used to minimize certain image defects known as excess brightness defects caused by major variations in the number of cells activated. For this purpose, the invention operates on the sub-division of the activation times of the cells during a given cycle time to reduce a time during which cells, selected as a function of their luminance level, are the only ones to be activated. The disclosed method can be applied especially to the control of alternating type plasma panels.

Growing community of inventors

Grenoble, France

Philippe Zorzan