Commissariat a L'energie Atomique

Other

Jean F Clerc

Jacques Robert

Denis Sarrasin

Cathodoluminescent display means using guided electrons and its control

The invention relates to a matrix display provided with a coupling compensation device between the rows and columns. The matrix display comprises a material, whose optical characteristic can be modified, said material being interposed between a group of row electrodes and a group of column electrodes, whose intersections X.sub.i Y.sub.j are the addressable points of the matrix display. It also comprises at least one compensation electrode and means for raising said compensation electrode to an appropriate potential for eliminating parasitic charges appearing on the row electrodes.

Matrix display and method of capacitance compensation via charge

The invention relates to a sequential control process for a matrix display using the cholesteric - nematic phase transition effect of a liquid crystal. This process consists of sequentially applying to the columns of electrodes of the display, a blanking signal followed by an addressing signal, the rows of electrodes of said display being addressed in parallel, in order to obtain the displayed or undisplayed state of the liquid crystal, followed by the sequential application of an addressing signal to the rows of electrodes, the columns of electrodes being addressed in parallel, in order to maintain the displayed or undisplayed state of the liquid crystal, while significantly improving the contrast.

Sequential control process for a matrix display

Control process for a matrix display comprising a material, whereof an optical property is to be modified, said material being placed between a first group of p parallel electrode rows and a second group of q parallel electrode columns, the rows and columns crossing one another, an area ij of the material being defined by the region of the material covered by row i, in which i is an integer such that 1.ltoreq.i.ltoreq.p, and by the column j, in which j is an integer such that 1.ltoreq.j.ltoreq.q, the rows and columns being used for carrying signals bringing about an excitation of the material, wherein the electrode rows have n horizontal gaps defining n+1 identical sets of electrode columns, a signal I is applied to electrode row i, while a zero signal is applied to the other electrode rows, the signal I being sequentially applied to the p electrode rows in accordance with increasing values of i, and wherein a signal J is applied to the electrode columns, said signal J being simultaneously applied to the electrode columns of the first set, during the application time of signal I to the p/n first electrode rows, the electrode columns of the other sets receiving a zero signal, then the electrode columns of the second set during the application time of signal I to the p/n following electrode rows, the electrode columns of the first set and other sets receiving a zero signal and so on up to the excitation of the electrode columns of the nth set.

Matrix display control process

The invention relates to a matrix display device with a plurality of sets of electrodes as well as to the process for controlling the same. The device comprises two insulating walls and by a material having a plurality of zones distributed in matrix-like manner and inserted between a first system of electrodes covering one of the two walls and defining p control columns and a second system of electrodes covering the other wall, constituted by parallel conductive strips, and defining q control lines, the column x.sub.i in which i is an integer such that 1.ltoreq.i.ltoreq.p and row y.sub.j in which j is an integer such that 1.ltoreq.j.ltoreq.q defining a zone x.sub.i y.sub.j of the material. The first system is constituted by a solid layer of electrodes and n sets of electrodes, which are electrically insulated from one another. The electrodes of this system being grouped in such a way that each group of electrodes corresponds to a single control row.

Matrix display device with multiple screen electrodes

A matrix display device having two groups of row electrodes and a process for the control thereof. This device is constituted by two insulating walls made from a material having several zones distributed in matrix-like manner, a first group of p rows of parallel electrodes covering one of the walls and a second group of q columns of parallel electrodes covering the other wall. A zone x.sub.i y.sub.j is defined by the overlap of row x.sub.i and column y.sub.j in which i varies from l to p and j from l to q. The said device also comprises a third group of p rows of electrodes, identical to the first group and placed on the second group, while being electrically insulated from the latter by an insulating layer.

Matrix display device

Process for the control of an optical characteristic of a material intercalated between two electrodes to which are applied excitation signals, wherein in order to bring about an excitation of the material a series of elementary signals is applied to the electrodes for increasing periods of time, each elementary signal either being equal to a constant or zero, all these elementary signals constituting a decomposition of the desired excitation into a given base. An application is in the field of optoelectronics and more particularly in the control of liquid crystal cells.

Process for the control of an optical characteristic of a material by

The invention relates to a process for positioning the liquid medium in a liquid medium cell and to a corresponding cell. The cell comprises a liquid medium placed between two walls kept spaced from one another, e.g. by shims, and joined along the edge thereof, wherein it comprises first means for producing a first surface tension force in a first area and second means for producing a second surface tension force in a second area, the first surface tension force being higher the the second surface tension force, said means serving to correctly position the liquid medium between the two walls, the liquid medium then being located in the first area and outside the second area.

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Meylan, France

Jean F Clerc