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EP0844642A1 - Flat panel display with focusing gates - Google Patents

Flat panel display with focusing gates Download PDF

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Publication number
EP0844642A1
EP0844642A1 EP97410133A EP97410133A EP0844642A1 EP 0844642 A1 EP0844642 A1 EP 0844642A1 EP 97410133 A EP97410133 A EP 97410133A EP 97410133 A EP97410133 A EP 97410133A EP 0844642 A1 EP0844642 A1 EP 0844642A1
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EP
European Patent Office
Prior art keywords
grid
additional
grids
color
orifices
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97410133A
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German (de)
French (fr)
Inventor
Jean-Luc Grand-Clément
Axel Jäger
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Pixtech SA
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Pixtech SA
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Publication date
Application filed by Pixtech SA filed Critical Pixtech SA
Publication of EP0844642A1 publication Critical patent/EP0844642A1/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • H01J31/123—Flat display tubes
    • H01J31/125—Flat display tubes provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digital selection
    • H01J31/127—Flat display tubes provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digital selection using large area or array sources, i.e. essentially a source for each pixel group

Definitions

  • the present invention relates to a flat display screen color, and more specifically "to cathodoluminescence ", whose anode carries luminescent elements likely to be excited by electronic bombardment.
  • This electronic bombardment can come from microtips, from layers with low extraction potential or from a thermionic source.
  • Figure 1 shows, very schematically, the structure classic color microtip flat screen of the so-called type "with switched anode".
  • Such a microtip screen essentially consists a cathode 1 with microtips 2 and a grid 3 provided with holes 4 corresponding to the locations of the microtips 2.
  • the cathode / grid is placed opposite a cathodoluminescent anode 5 from which it is separated by a vacuum space 12 and of which a glass substrate 6 constitutes the screen surface.
  • Cathode 1 is organized in columns and is made up, on a glass substrate 10, cathode conductors organized in mesh from a conductive layer.
  • the microtips 2 are made on a resistive layer 11 deposited on the cathode conductors and are arranged inside meshes defined by the cathode conductors.
  • Figure 1 partially represents the interior of a mesh and the conductors cathode do not appear in this figure.
  • Cathode 1 is associated with grid 3 organized in lines. The intersection a row of grid 3 and a column of cathode 1 defines a pixel.
  • Anode 5 is generally provided with alternating bands phosphor elements 7r, 7g, 7b each corresponding to a color (Red, Green, Blue).
  • the bands are parallel to the cathode columns and are separated from each other by an insulator 8.
  • the phosphor elements 7 are deposited on electrodes 9 consisting of corresponding strips of a layer transparent conductor such as indium tin oxide (ITO).
  • ITO indium tin oxide
  • the sets of red, green, blue bands are alternately polarized with respect to cathode 1, so that electrons extracted from microtips 2 of a pixel by the field electric created between cathode 1 and grid 3 are alternately attracted by the phosphor elements 7 of each of the colors.
  • anode-cathode voltage and therefore the distance anode-cathode defined by space 12.
  • non-switched anode screens of which the anode is made up phosphor elements of different colors, all polarized simultaneously with the same potential.
  • this type of screen the selection of the color of the phosphor element to be excited is obtained, cathode side, by subdividing each column of the cathode into three sub-columns respectively associated with each of the colors.
  • the second stray light problem subsists. This phenomenon is even more critical here because the electrons also bombard phosphor elements from another color.
  • the present invention aims to overcome the drawbacks classic screens by offering a color flat screen of unswitched anode display capable of withstanding high inter-electrode voltage (of the order of 2 to 10 keV) without harming the definition of the screen.
  • the present invention also aims to provide such a high-voltage inter-electrode flat screen that does not require to switch the cathode conductors according to the color to display.
  • the present invention provides a flat color display screen with a cathode associated with an electron extraction grid; a anode provided with at least two types of phosphor elements, all polarized at the same potential; and at least two additional grids superimposed, reported on the extraction grid, isolated from each other and from the extraction grid, and provided with coaxial orifices defining associated sub-pixels each color, each additional grid being associated one color and having holes, smaller diameter than the coaxial orifices of the other additional grids, to activate the sub-pixels of the corresponding color.
  • each additional grid has two sets of different diameters, the diameter of the smaller holes diameter of each additional grid being less than diameter of the larger diameter orifices of the other grids additional.
  • each additional grid consists of a metal sheet perforated.
  • this screen includes means for individually polarizing the additional grids.
  • the present invention also provides a method of control of a flat color display screen consisting of sequentially polarize each additional grid to a respective activation potential of the color sub-pixels corresponding, the other additional grids being brought to respective inhibitory potentials of the sub-pixels of the corresponding colors.
  • the respective activation potentials of the additional grids are positive or zero, their respective inhibition potentials being less than a minimum potential for polarization of the cathode.
  • the activation potential of each additional grid is chosen according to the diameter of its smallest holes diameter.
  • the activation potential of each additional grid is chosen according to the distance between this grid additional extraction grid.
  • the respective inhibition potentials of the additional grids are the same.
  • the polarization potential of the phosphor elements of the anode is between 2 and 10 keV.
  • FIG. 2 is a sectional view of an embodiment of a microtip screen according to the present invention.
  • this screen includes a cathode 1 to microtips 2 and an extraction grid 3 provided with holes 4 corresponding to the locations of the microtips 2.
  • a mesh of cathode conductors organized in columns is carried out on a glass substrate 10.
  • the microtips 2 rest on a layer resistive formed on and between the cathode conductors and are arranged inside the meshes defined by the conductors cathode.
  • the resistive layer and the conductors of cathode of a column have been designated globally by the reference 13.
  • Grid 3 is, as before, organized in lines. The intersection of a line in grid 3 and a column 13 of cathode 1 defines a pixel.
  • the cathode / grid is associated with a 5 'anode made up of regions (for example, parallel strips alternating as in FIG. 1) of phosphor elements 7r, 7g and 7b deposited on a common electrode 9 consisting of a plane a transparent conductive layer such as oxide indium and tin (ITO). Layer 9 is deposited on a glass substrate 6 constituting the surface of the screen. So, all the phosphor elements 7 are simultaneously polarized by compared to cathode 1.
  • a 5 'anode made up of regions (for example, parallel strips alternating as in FIG. 1) of phosphor elements 7r, 7g and 7b deposited on a common electrode 9 consisting of a plane a transparent conductive layer such as oxide indium and tin (ITO). Layer 9 is deposited on a glass substrate 6 constituting the surface of the screen. So, all the phosphor elements 7 are simultaneously polarized by compared to cathode 1.
  • a characteristic of a screen according to the present invention is that it includes, on the cathode side, a grid structure additional 14 focusing electrons emitted by microtips to regions of phosphor elements 7 similarly color.
  • the structure 14 is, in this embodiment, consisting of three focusing grids 15, 16 and 17, respectively associated with each of the colors. We will speak below of “red”, “green” and “blue” grids. Grids 15, 16 and 17 are reported on the extraction grid 3 and are separated the from each other and from the grid 3 by an insulator 18.
  • Each screen pixel (defined by the intersection of a row of grid 3 with a column 13 of cathode 1) is subdivided into three sub-pixels, respectively Pr, Pg and Pb, defined by three coaxial orifices made in the grids 15, 16 and 17.
  • Each sub-pixel of the cathode / grids Pr, Pg, Pb is next to a region of phosphor elements, respectively 7r, 7g or 7b corresponding to the sub-pixel of the color considered, anode side 5 '.
  • phosphor elements respectively 7r, 7g or 7b corresponding to the sub-pixel of the color considered, anode side 5 '.
  • microtips are, in practice, among the number of several thousand per pixel of screen.
  • each "red” grid 15, “green” 16 or “blue” 17 has holes, respectively 19, 21 or 23, activation or inhibition of color sub-pixels corresponding.
  • the holes 19, 21 or 23 of each grid 15, 16 or 17 are of reduced diameter compared to the orifices coaxial, respectively 22 and 24, 20 and 24, or 20 and 22, two other grids.
  • the role of orifices 19, 21 and 23 in diameter reduced is to allow, depending on the polarization of the grids 15, 16 and 17, either to block or to focus the electrons emitted by the microtips 2 opposite the orifices 19, 21 and 23 depending on the color to be displayed.
  • the grids 15, 16 and 17 comprise, each, two series of orifices, respectively 19 and 20, 21 and 22, or 23 and 24, of different diameters.
  • FIGS. 3A to 3C illustrate the operation of a screen according to the invention.
  • Figures 3A, 3B and 3C show schematically an example of polarization of additional grids 15, 16 and 17 of a screen according to the invention, respectively, for each of the three colors.
  • the details of the cathode 1 and the extraction grid 3 have not been reproduced in FIGS. 3A to 3C.
  • the display is made by sub-frames associated with each color.
  • the rows of grid 3 are sequentially polarized at a potential of the order of 80 volts, while the columns 13 of the cathode 1 are brought to respective potentials between a maximum emission potential and a potential for no emissions (for example, respectively 0 and 30 volts).
  • the 5 ′ anode is polarized at a high potential (for example, of the order of 2 to 10 keV).
  • the "red" grid 15 is polarized at a potential positive activation (for example, +30 volts), while the "green” 16 and “blue” 17 grids are polarized to a potential more negative inhibition than the minimum polarization potential columns 13 of cathode 1 (for example, -30 volts).
  • the electrons emitted opposite the orifices 19, along the grid line 3 polarized are focused by the grid "red” 15 to bombard phosphor elements 7r of the sub-pixels correspondents.
  • the electrons emitted opposite orifices 21 and 23 are blocked by the negative potential of polarization of the "green” 16 and "blue” 17 grids and are then collected by the extraction grid 3 at a potential of 80 volts.
  • the value of the activation potential of the grid 15, 16 or 17 to focus the electrons depends, in particular, on the distance of this grid from the extraction grid 3, as well as the diameter of its reduced diameter orifices, 19, 21 or 23 respectively.
  • the activation potential of the grid furthest from grid 3 (here, the "red” grid 15) is the most positive and the activation potential of the grid closest to cathode 1 (here, the "blue” grid 17) is the least positive, even zero.
  • the negative inhibition potentials two additional grids, used to block the electrons from sub-pixels not matching the color at display may be different from each other.
  • the orifice of diameter reduced by a sub-pixel given either to a negative potential to block the electrons the choice of a unique negative inhibition potential allows simplify the control of the structure 14 by means of a circuit screen control electronics.
  • the reduced diameter of the openings 19, 21 or 23 of each grid, respectively 15, 16 or 17, is chosen according to the inter-electrode distance (therefore, inter-electrode voltage) to focus the electrons on the regions phosphor elements associated with the corresponding orifices.
  • the orifices 19, 21 and 23 have a shape chosen to optimize focusing and blocking electrons according to their polarization.
  • the edges can be straight, rounded, pointed, or bevelled towards the anode or the cathode.
  • the diameters of the orifices 19, 21 and 23 can be different from each other, provided that these diameters are, respectively, smaller than the diameters of the orifices (22 and 24, 20 and 24, 20 and 22) of the other grids (16 and 17, 15 and 17, 15 and 16) with which they are coaxial.
  • the thickness of the additional grids 15, 16 and 17 is very much greater than the thickness of the constituent layers of cathode 1 associated with extraction grid 3.
  • the overall thickness of the associated cathode 1 at grid 3 is of the order of 1 to 5 ⁇ m, for example 3.5 ⁇ m, and the thickness of each additional grid 15, 16 or 17 is around 50 ⁇ m.
  • An advantage of the present invention is that it allows to produce a high-voltage inter-electrode display screen without the need for switching components high voltage, the selection of the color to be displayed being performed by the structure 14 of additional grids at low voltage.
  • Another advantage of the present invention is that it guarantees optimal focusing of electrons towards the sub-pixels of the corresponding color.
  • the columns 13 of cathode 1 can be subdivided into addressed sub-columns independently of each other. In this case, selecting the color is carried out by means of the cathode sub-columns.
  • the structure 14 of additional grids then has the role of guarantee optimal focusing of electrons and allow a high inter-electrode voltage.
  • Another advantage of the present invention is that allowing the polarization of the anode under a high voltage, we can now use phosphor elements like those used in color television cathode ray tubes including the manufacturing techniques are perfectly mastered.
  • Another advantage of the present invention is that allowing the production of an anode whose phosphor elements are all polarized simultaneously, the alternating bands phosphor elements conventionally used in screens with microtips can be replaced with element pellets phosphors of each color corresponding to each sub-pixel.
  • Figure 4 is a top view of a structure of additional grids according to the present invention intended for be associated with an anode carrying three pellets of elements phosphors of different colors for each pixel.
  • the holes 19 to 23 of the structure 14 are then arranged, for each pixel defined by the intersection of a line 25 of grid 3 and a column 13 of cathode 1, in depending on the arrangement, on the anode side, of the element pellets phosphors (not shown).
  • the sub-pixels of a given pixel are arranged substantially triangular, which helps balance the bulk of each pixel in both directions.
  • the distribution of sub-pixels must remain consistent with the organization in columns or in sub-columns of the cathode.
  • the invention also applies in case the anode is provided with two different types phosphor elements, for example, to a two-color screen, the phosphor elements are distributed by pellets of the size of a sub-pixel or in strips the width of a sub-pixel. In this case, only two additional grids according to the invention are provided.
  • each additional grid 15, 16, 17 consists of a perforated metal sheet isolated on at least one of its faces. These sheets are assembled so as to align their openings then are arranged on the extraction grid of the plate screen cathode. Then an anode plate is mounted on the upper grid with interposition of spacers. Nevertheless many variant embodiments will appear to the man of art.
  • the present invention is capable of various variants and modifications which will appear to the man of art.
  • shape and diameter of the orifices of the additional grids as well as the respective potentials activation and inhibition of additional grids will chosen to optimize the focusing towards the sub-pixels correspondents.

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  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

The focussing grid structure is formed to focus onto an anode with different luminous elements (7r,7g,7b) all at the same voltage. Micropoints (2) are placed between an output grid (3) and three additional grids (15,16,17) are placed on top. Each grid defines a coaxial hole (19,20;21,22;23,24) in that area. The additional grids are arranged to activate the sub-pixels of the different colours.

Description

La présente invention concerne un écran plat de visualisation couleur, et plus particulièrement des écrans dits "à cathodoluminescence", dont l'anode porte des éléments luminescents susceptibles d'être excités par bombardement électronique. Ce bombardement électronique peut provenir de micropointes, de couches à faible potentiel d'extraction ou d'une source thermoionique.The present invention relates to a flat display screen color, and more specifically "to cathodoluminescence ", whose anode carries luminescent elements likely to be excited by electronic bombardment. This electronic bombardment can come from microtips, from layers with low extraction potential or from a thermionic source.

Pour simplifier la présente description, on ne considérera ci-après que les écrans couleurs à micropointes, mais on notera que l'invention concerne, de façon générale, les divers types d'écrans susmentionnés et analogues.To simplify this description, we will not consider below as color microtip screens, but we note that the invention relates, in general, to the various types of screens mentioned above and the like.

La figure 1 représente, très schématiquement, la structure classique d'un écran plat couleur à micropointes du type dit "à anode commutée".Figure 1 shows, very schematically, the structure classic color microtip flat screen of the so-called type "with switched anode".

Un tel écran à micropointes est essentiellement constitué d'une cathode 1 à micropointes 2 et d'une grille 3 pourvue de trous 4 correspondants aux emplacements des micropointes 2. La cathode/grille est placée en regard d'une anode cathodoluminescente 5 dont elle est séparée par un espace sous vide 12 et dont un substrat de verre 6 constitue la surface d'écran.Such a microtip screen essentially consists a cathode 1 with microtips 2 and a grid 3 provided with holes 4 corresponding to the locations of the microtips 2. The cathode / grid is placed opposite a cathodoluminescent anode 5 from which it is separated by a vacuum space 12 and of which a glass substrate 6 constitutes the screen surface.

La cathode 1 est organisée en colonnes et est constituée, sur un substrat de verre 10, de conducteurs de cathode organisés en mailles à partir d'une couche conductrice. Les micropointes 2 sont réalisées sur une couche résistive 11 déposée sur les conducteurs de cathode et sont disposées à l'intérieur des mailles définies par les conducteurs de cathode. La figure 1 représente partiellement l'intérieur d'une maille et les conducteurs de cathode n'apparaissent pas sur cette figure. La cathode 1 est associée à la grille 3 organisée en lignes. L'intersection d'une ligne de la grille 3 et d'une colonne de la cathode 1 définit un pixel.Cathode 1 is organized in columns and is made up, on a glass substrate 10, cathode conductors organized in mesh from a conductive layer. The microtips 2 are made on a resistive layer 11 deposited on the cathode conductors and are arranged inside meshes defined by the cathode conductors. Figure 1 partially represents the interior of a mesh and the conductors cathode do not appear in this figure. Cathode 1 is associated with grid 3 organized in lines. The intersection a row of grid 3 and a column of cathode 1 defines a pixel.

L'anode 5 est généralement pourvue de bandes alternées d'éléments luminophores 7r, 7g, 7b correspondant chacune à une couleur (Rouge, Vert, Bleu). Les bandes sont parallèles aux colonnes de la cathode et sont séparées les unes des autres par un isolant 8. Les éléments luminophores 7 sont déposés sur des électrodes 9 constituées de bandes correspondantes d'une couche conductrice transparente telle que de l'oxyde d'indium et d'étain (ITO). Les ensembles de bandes rouges, vertes, bleues, sont alternativement polarisés par rapport à la cathode 1, pour que des électrons extraits des micropointes 2 d'un pixel par le champ électrique créé entre la cathode 1 et la grille 3 soient alternativement attirés par les éléments luminophores 7 de chacune des couleurs.Anode 5 is generally provided with alternating bands phosphor elements 7r, 7g, 7b each corresponding to a color (Red, Green, Blue). The bands are parallel to the cathode columns and are separated from each other by an insulator 8. The phosphor elements 7 are deposited on electrodes 9 consisting of corresponding strips of a layer transparent conductor such as indium tin oxide (ITO). The sets of red, green, blue bands are alternately polarized with respect to cathode 1, so that electrons extracted from microtips 2 of a pixel by the field electric created between cathode 1 and grid 3 are alternately attracted by the phosphor elements 7 of each of the colors.

Pour augmenter la brillance de l'écran, il est souhaitable d'augmenter la tension anode-cathode et donc la distance anode-cathode définie par l'espace 12. Ceci pose notamment deux problèmes. Le premier est qu'il est difficile, avec des composants existants, de commuter rapidement des tensions élevées, et que cela entraíne une forte consommation de puissance. Le deuxième est que, plus l'espace inter-électrodes est important, plus les électrons émis par les micropointes se dispersent et ont tendance à provoquer un éclairement parasite des pixels voisins de celui que l'on cherche à illuminer.To increase the brightness of the screen, it is desirable increase the anode-cathode voltage and therefore the distance anode-cathode defined by space 12. This poses in particular two problems. The first is that it is difficult, with components existing, quickly switch high voltages, and that this results in a high consumption of power. The second is that the larger the inter-electrode space, the more the electrons emitted by the microtips disperse and have tendency to cause stray light from neighboring pixels of the one we are trying to illuminate.

Pour résoudre le premier problème, on peut utiliser des écrans dits "à anode non commutée" dont l'anode est constituée d'éléments luminophores de couleurs différentes, tous polarisés simultanément à un même potentiel. Dans ce type d'écran, la sélection de la couleur de l'élément luminophore devant être excité est obtenue, côté cathode, en subdivisant chaque colonne de la cathode en trois sous-colonnes respectivement associées à chacune des couleurs.To solve the first problem, we can use so-called "non-switched anode" screens of which the anode is made up phosphor elements of different colors, all polarized simultaneously with the same potential. In this type of screen, the selection of the color of the phosphor element to be excited is obtained, cathode side, by subdividing each column of the cathode into three sub-columns respectively associated with each of the colors.

Toutefois, le deuxième problème d'éclairement parasite subsiste. Ce phénomène est ici encore plus critique car les électrons bombardent également des éléments luminophores d'une autre couleur.However, the second stray light problem subsists. This phenomenon is even more critical here because the electrons also bombard phosphor elements from another color.

La présente invention vise à pallier les inconvénients des écrans classiques en proposant un écran plat couleur de visualisation à anode non commutée pouvant supporter une haute tension inter-électrodes (de l'ordre de 2 à 10 keV) sans nuire à la définition de l'écran.The present invention aims to overcome the drawbacks classic screens by offering a color flat screen of unswitched anode display capable of withstanding high inter-electrode voltage (of the order of 2 to 10 keV) without harming the definition of the screen.

La présente invention vise également à proposer un tel écran plat à haute tension inter-électrodes qui ne nécessite pas de commuter les conducteurs de cathode en fonction de la couleur à afficher.The present invention also aims to provide such a high-voltage inter-electrode flat screen that does not require to switch the cathode conductors according to the color to display.

Pour atteindre ces objets, la présente invention prévoit un écran plat de visualisation couleur comportant une cathode associée à une grille d'extraction d'électrons ; une anode pourvue d'au moins deux types d'éléments luminophores, tous polarisés à un même potentiel ; et au moins deux grilles additionnelles superposées, rapportées sur la grille d'extraction, isolées les unes des autres et de la grille d'extraction, et pourvues d'orifices coaxiaux définissant des sous-pixels associés à chacune des couleurs, chaque grille additionnelle étant associée à une couleur et comportant des orifices, de plus petit diamètre que les orifices coaxiaux des autres grilles additionnelles, pour activer les sous-pixels de la couleur correspondante.To achieve these objects, the present invention provides a flat color display screen with a cathode associated with an electron extraction grid; a anode provided with at least two types of phosphor elements, all polarized at the same potential; and at least two additional grids superimposed, reported on the extraction grid, isolated from each other and from the extraction grid, and provided with coaxial orifices defining associated sub-pixels each color, each additional grid being associated one color and having holes, smaller diameter than the coaxial orifices of the other additional grids, to activate the sub-pixels of the corresponding color.

Selon un mode de réalisation de la présente invention, chaque grille additionnelle comporte deux séries d'orifices de diamètres différents, le diamètre des orifices de plus petit diamètre de chaque grille additionnelle étant inférieur au diamètre des orifices de plus grand diamètre des autres grilles additionnelles.According to an embodiment of the present invention, each additional grid has two sets of different diameters, the diameter of the smaller holes diameter of each additional grid being less than diameter of the larger diameter orifices of the other grids additional.

Selon un mode de réalisation de la présente invention, chaque grille additionnelle est constituée d'une feuille métallique perforée.According to an embodiment of the present invention, each additional grid consists of a metal sheet perforated.

Selon un mode de réalisation de la présente invention, cet écran comporte des moyens pour polariser individuellement les grilles additionnelles.According to an embodiment of the present invention, this screen includes means for individually polarizing the additional grids.

La présente invention prévoit aussi un procédé de commande d'un écran plat de visualisation couleur consistant à polariser séquentiellement chaque grille additionnelle à un potentiel respectif d'activation des sous-pixels de la couleur correspondante, les autres grilles additionnelles étant portées à des potentiels respectifs d'inhibition des sous-pixels des couleurs correspondantes.The present invention also provides a method of control of a flat color display screen consisting of sequentially polarize each additional grid to a respective activation potential of the color sub-pixels corresponding, the other additional grids being brought to respective inhibitory potentials of the sub-pixels of the corresponding colors.

Selon un mode de réalisation de la présente invention, les potentiels respectifs d'activation des grilles additionnelles sont positifs ou nuls, leurs potentiels respectifs d'inhibition étant inférieurs à un potentiel minimal de polarisation de la cathode.According to an embodiment of the present invention, the respective activation potentials of the additional grids are positive or zero, their respective inhibition potentials being less than a minimum potential for polarization of the cathode.

Selon un mode de réalisation de la présente invention, le potentiel d'activation de chaque grille additionnelle est choisi en fonction du diamètre de ses orifices de plus petit diamètre.According to an embodiment of the present invention, the activation potential of each additional grid is chosen according to the diameter of its smallest holes diameter.

Selon un mode de réalisation de la présente invention, le potentiel d'activation de chaque grille additionnelle est choisi en fonction de la distance qui sépare cette grille additionnelle de la grille d'extraction.According to an embodiment of the present invention, the activation potential of each additional grid is chosen according to the distance between this grid additional extraction grid.

Selon un mode de réalisation de la présente invention, les potentiels respectifs d'inhibition des grilles additionnelles sont identiques.According to an embodiment of the present invention, the respective inhibition potentials of the additional grids are the same.

Selon un mode de réalisation de la présente invention, le potentiel de polarisation des éléments luminophores de l'anode est compris entre 2 et 10 keV. According to an embodiment of the present invention, the polarization potential of the phosphor elements of the anode is between 2 and 10 keV.

Ces objets, caractéristiques et avantages, ainsi que d'autres de la présente invention seront exposés en détail dans la description suivante de modes de réalisation particuliers faite à titre non-limitatif en relation avec les figures jointes parmi lesquelles :

  • la figure 1, décrite précédemment, est destinée à exposer l'état de la technique et le problème posé ;
  • la figure 2 représente, partiellement et en coupe, un mode de réalisation d'un écran plat selon la présente invention ;
  • les figures 3A à 3C illustrent le fonctionnement d'un écran selon la présente invention ; et
  • la figure 4 est une vue partielle de dessus d'une cathode/grilles selon un mode de réalisation de la présente invention.
    • These objects, characteristics and advantages, as well as others of the present invention will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:
  • Figure 1, described above, is intended to expose the state of the art and the problem posed;
  • Figure 2 shows, partially and in section, an embodiment of a flat screen according to the present invention;
  • FIGS. 3A to 3C illustrate the operation of a screen according to the present invention; and
  • Figure 4 is a partial top view of a cathode / grids according to an embodiment of the present invention.

    • Les mêmes éléments ont été désignés par les mêmes références aux différentes figures. Pour des raisons de clarté, les représentations des figures ne sont pas à l'échelle.The same elements have been designated by the same references to the different figures. For reasons of clarity, the representations of the figures are not to scale.

    La figure 2 est une vue en coupe d'un mode de réalisation d'un écran à micropointes selon la présente invention. Comme précédemment (figure 1), cet écran comporte une cathode 1 à micropointes 2 et une grille d'extraction 3 pourvue de trous 4 correspondant aux emplacements des micropointes 2. Un maillage de conducteurs de cathode organisés en colonnes est réalisé sur un substrat de verre 10. Les micropointes 2 reposent sur une couche résistive formée sur et entre les conducteurs de cathode et sont disposées à l'intérieur des mailles définies par les conducteurs de cathode. A la figure 2, la couche résistive et les conducteurs de cathode d'une colonne ont été désignés globalement par la référence 13. La grille 3 est, comme précédemment, organisée en lignes. L'intersection d'une ligne de la grille 3 et d'une colonne 13 de la cathode 1 définit un pixel.Figure 2 is a sectional view of an embodiment of a microtip screen according to the present invention. As previously (Figure 1), this screen includes a cathode 1 to microtips 2 and an extraction grid 3 provided with holes 4 corresponding to the locations of the microtips 2. A mesh of cathode conductors organized in columns is carried out on a glass substrate 10. The microtips 2 rest on a layer resistive formed on and between the cathode conductors and are arranged inside the meshes defined by the conductors cathode. In FIG. 2, the resistive layer and the conductors of cathode of a column have been designated globally by the reference 13. Grid 3 is, as before, organized in lines. The intersection of a line in grid 3 and a column 13 of cathode 1 defines a pixel.

    Selon l'invention, la cathode/grille est associée à une anode 5' constituée de régions (par exemple, des bandes parallèles alternées comme à la figure 1) d'éléments luminophores 7r, 7g et 7b déposés sur une électrode commune 9 constituée d'un plan d'une couche conductrice transparente telle que de l'oxyde d'indium et d'étain (ITO). La couche 9 est déposée sur un substrat de verre 6 constituant la surface de l'écran. Ainsi, tous les éléments luminophores 7 sont simultanément polarisés par rapport à la cathode 1.According to the invention, the cathode / grid is associated with a 5 'anode made up of regions (for example, parallel strips alternating as in FIG. 1) of phosphor elements 7r, 7g and 7b deposited on a common electrode 9 consisting of a plane a transparent conductive layer such as oxide indium and tin (ITO). Layer 9 is deposited on a glass substrate 6 constituting the surface of the screen. So, all the phosphor elements 7 are simultaneously polarized by compared to cathode 1.

    Une caractéristique d'un écran selon la présente invention est qu'il comporte, côté cathode, une structure de grilles additionnelles 14 de focalisation des électrons émis par les micropointes vers des régions d'éléments luminophores 7 de même couleur. La structure 14 est, dans ce mode de réalisation, constituée de trois grilles de focalisation 15, 16 et 17, respectivement associées à chacune des couleurs. On parlera ci-après de grilles "rouge", "verte" et "bleue". Les grilles 15, 16 et 17 sont rapportées sur la grille d'extraction 3 et sont séparées les unes des autres et de la grille 3 par un isolant 18.A characteristic of a screen according to the present invention is that it includes, on the cathode side, a grid structure additional 14 focusing electrons emitted by microtips to regions of phosphor elements 7 similarly color. The structure 14 is, in this embodiment, consisting of three focusing grids 15, 16 and 17, respectively associated with each of the colors. We will speak below of "red", "green" and "blue" grids. Grids 15, 16 and 17 are reported on the extraction grid 3 and are separated the from each other and from the grid 3 by an insulator 18.

    Chaque pixel de l'écran (défini par l'intersection d'une ligne de la grille 3 avec une colonne 13 de la cathode 1) est subdivisé en trois sous-pixels, respectivement Pr, Pg et Pb, définis par trois orifices coaxiaux réalisés dans les grilles 15, 16 et 17. Chaque sous-pixel de la cathode/grilles Pr, Pg, Pb est en regard d'une région d'éléments luminophores, respectivement 7r, 7g ou 7b correspondant au sous-pixel de la couleur considérée, côté anode 5'. Pour des raisons de clarté, seules deux micropointes 2 ont été représentées par sous-pixel. On notera toutefois que les micropointes sont, en pratique, au nombre de plusieurs milliers par pixel d'écran.Each screen pixel (defined by the intersection of a row of grid 3 with a column 13 of cathode 1) is subdivided into three sub-pixels, respectively Pr, Pg and Pb, defined by three coaxial orifices made in the grids 15, 16 and 17. Each sub-pixel of the cathode / grids Pr, Pg, Pb is next to a region of phosphor elements, respectively 7r, 7g or 7b corresponding to the sub-pixel of the color considered, anode side 5 '. For the sake of clarity, only two 2 microtips have been represented by sub-pixel. We will note however, microtips are, in practice, among the number of several thousand per pixel of screen.

    Selon l'invention, chaque grille "rouge" 15, "verte" 16 ou "bleue" 17 comporte des orifices, respectivement 19, 21 ou 23, d'activation ou d'inhibition des sous-pixels de la couleur correspondante. Les orifices 19, 21 ou 23 de chaque grille 15, 16 ou 17 sont d'un diamètre réduit par rapport aux orifices coaxiaux, respectivement 22 et 24, 20 et 24, ou 20 et 22, des deux autres grilles. Le rôle des orifices 19, 21 et 23 de diamètre réduit est de permettre, selon la polarisation des grilles 15, 16 et 17, soit de bloquer, soit de focaliser les électrons émis par les micropointes 2 en regard des orifices 19, 21 et 23 en fonction de la couleur à afficher. De préférence et comme le représente la figure 2, les grilles 15, 16 et 17 comportent, chacune, deux séries d'orifices, respectivement 19 et 20, 21 et 22, ou 23 et 24, de diamètres différents.According to the invention, each "red" grid 15, "green" 16 or "blue" 17 has holes, respectively 19, 21 or 23, activation or inhibition of color sub-pixels corresponding. The holes 19, 21 or 23 of each grid 15, 16 or 17 are of reduced diameter compared to the orifices coaxial, respectively 22 and 24, 20 and 24, or 20 and 22, two other grids. The role of orifices 19, 21 and 23 in diameter reduced is to allow, depending on the polarization of the grids 15, 16 and 17, either to block or to focus the electrons emitted by the microtips 2 opposite the orifices 19, 21 and 23 depending on the color to be displayed. Preferably and like the represents FIG. 2, the grids 15, 16 and 17 comprise, each, two series of orifices, respectively 19 and 20, 21 and 22, or 23 and 24, of different diameters.

    Les figures 3A à 3C illustrent le fonctionnement d'un écran selon l'invention. Les figures 3A, 3B et 3C représentent schématiquement un exemple de polarisation des grilles additionnelles 15, 16 et 17 d'un écran selon l'invention, respectivement, pour chacune des trois couleurs. Pour des raisons de clarté, les détails constitutifs de la cathode 1 et de la grille d'extraction 3 n'ont pas été reproduits aux figures 3A à 3C.FIGS. 3A to 3C illustrate the operation of a screen according to the invention. Figures 3A, 3B and 3C show schematically an example of polarization of additional grids 15, 16 and 17 of a screen according to the invention, respectively, for each of the three colors. For reasons of clarity, the details of the cathode 1 and the extraction grid 3 have not been reproduced in FIGS. 3A to 3C.

    L'affichage s'effectue par sous-trames associées à chaque couleur. Par exemple, les rangées de la grille 3 sont séquentiellement polarisées à un potentiel de l'ordre de 80 volts, tandis que les colonnes 13 de la cathode 1 sont portées à des potentiels respectifs compris entre un potentiel d'émission maximale et un potentiel d'absence d'émission (par exemple, respectivement 0 et 30 volts). De préférence, l'anode 5' est polarisée à un fort potentiel (par exemple, de l'ordre de 2 à 10 keV).The display is made by sub-frames associated with each color. For example, the rows of grid 3 are sequentially polarized at a potential of the order of 80 volts, while the columns 13 of the cathode 1 are brought to respective potentials between a maximum emission potential and a potential for no emissions (for example, respectively 0 and 30 volts). Preferably, the 5 ′ anode is polarized at a high potential (for example, of the order of 2 to 10 keV).

    Pendant une première sous-trame (figure 3A), par exemple rouge, la grille "rouge" 15 est polarisée à un potentiel d'activation positif (par exemple, +30 volts), tandis que les grilles "verte" 16 et "bleue" 17 sont polarisées à un potentiel d'inhibition plus négatif que le potentiel minimal de polarisation des colonnes 13 de la cathode 1 (par exemple, -30 volts). Ainsi, les électrons émis en regard des orifices 19, le long de la ligne de grille 3 polarisée, sont focalisés par la grille "rouge" 15 pour bombarder des éléments luminophores 7r des sous-pixels correspondants. A l'inverse, les électrons émis en regard des orifices 21 et 23 sont bloqués par le potentiel négatif de polarisation des grilles "verte" 16 et "bleue" 17 et sont alors collectés par la grille d'extraction 3 au potentiel de 80 volts. During a first subframe (FIG. 3A), for example red, the "red" grid 15 is polarized at a potential positive activation (for example, +30 volts), while the "green" 16 and "blue" 17 grids are polarized to a potential more negative inhibition than the minimum polarization potential columns 13 of cathode 1 (for example, -30 volts). Thus, the electrons emitted opposite the orifices 19, along the grid line 3 polarized, are focused by the grid "red" 15 to bombard phosphor elements 7r of the sub-pixels correspondents. Conversely, the electrons emitted opposite orifices 21 and 23 are blocked by the negative potential of polarization of the "green" 16 and "blue" 17 grids and are then collected by the extraction grid 3 at a potential of 80 volts.

    Pendant les sous-trames suivantes (figure 3B et 3C), le fonctionnement décrit ci-dessus est reproduit pour la grille "verte" 16, puis "bleue" 17.During the following subframes (FIG. 3B and 3C), the operation described above is reproduced for the grid "green" 16, then "blue" 17.

    La valeur du potentiel d'activation de la grille 15, 16 ou 17 devant focaliser les électrons dépend, en particulier, de la distance de cette grille par rapport à la grille d'extraction 3, ainsi que du diamètre de ses orifices de diamètre réduit, respectivement 19, 21 ou 23. Par exemple, le potentiel d'activation de la grille la plus éloignée de la grille 3 (ici, la grille "rouge" 15) est le plus positif et le potentiel d'activation de la grille la plus proche de la cathode 1 (ici, la grille "bleue" 17) est le moins positif, voire nul.The value of the activation potential of the grid 15, 16 or 17 to focus the electrons depends, in particular, on the distance of this grid from the extraction grid 3, as well as the diameter of its reduced diameter orifices, 19, 21 or 23 respectively. For example, the activation potential of the grid furthest from grid 3 (here, the "red" grid 15) is the most positive and the activation potential of the grid closest to cathode 1 (here, the "blue" grid 17) is the least positive, even zero.

    On notera également que les potentiels négatifs d'inhibition des deux grilles additionnelles, servant à bloquer les électrons des sous-pixels ne correspondant pas à la couleur à afficher, peuvent être différents les uns des autres. Toutefois, comme il suffit que l'orifice de diamètre réduit d'un sous-pixel donné soit à un potentiel négatif pour bloquer les électrons, le choix d'un potentiel négatif unique d'inhibition permet de simplifier la commande de la structure 14 au moyen d'un circuit électronique de commande de l'écran.It should also be noted that the negative inhibition potentials two additional grids, used to block the electrons from sub-pixels not matching the color at display, may be different from each other. However, as it is enough that the orifice of diameter reduced by a sub-pixel given either to a negative potential to block the electrons, the choice of a unique negative inhibition potential allows simplify the control of the structure 14 by means of a circuit screen control electronics.

    Le diamètre réduit des orifices 19, 21 ou 23 de chaque grille, respectivement 15, 16 ou 17, est choisi en fonction de la distance inter-électrodes (donc, de la tension inter-électrodes) pour assurer une focalisation des électrons sur les régions d'éléments luminophores associées aux orifices correspondants. De plus, les orifices 19, 21 et 23 ont une forme choisie pour optimiser la focalisation et le blocage des électrons selon leur polarisation. Par exemple, les bords peuvent être droits, arrondis, en pointe, ou biseautés en direction de l'anode ou de la cathode.The reduced diameter of the openings 19, 21 or 23 of each grid, respectively 15, 16 or 17, is chosen according to the inter-electrode distance (therefore, inter-electrode voltage) to focus the electrons on the regions phosphor elements associated with the corresponding orifices. Of more, the orifices 19, 21 and 23 have a shape chosen to optimize focusing and blocking electrons according to their polarization. For example, the edges can be straight, rounded, pointed, or bevelled towards the anode or the cathode.

    Les diamètres des orifices 19, 21 et 23 peuvent être différents les uns des autres, pourvu que ces diamètres soient, respectivement, inférieurs aux diamètres des orifices (22 et 24, 20 et 24, 20 et 22) des autres grilles (16 et 17, 15 et 17, 15 et 16) avec lesquels ils sont coaxiaux.The diameters of the orifices 19, 21 and 23 can be different from each other, provided that these diameters are, respectively, smaller than the diameters of the orifices (22 and 24, 20 and 24, 20 and 22) of the other grids (16 and 17, 15 and 17, 15 and 16) with which they are coaxial.

    L'épaisseur des grilles additionnelles 15, 16 et 17 est très nettement supérieure à l'épaisseur des couches constitutives de la cathode 1 associée à la grille d'extraction 3. A titre d'exemple particulier, l'épaisseur globale de la cathode 1 associée à la grille 3 est de l'ordre de 1 à 5 µm, par exemple 3,5 µm, et l'épaisseur de chaque grille additionnelle 15, 16 ou 17 est de l'ordre de 50 µm.The thickness of the additional grids 15, 16 and 17 is very much greater than the thickness of the constituent layers of cathode 1 associated with extraction grid 3. As example, the overall thickness of the associated cathode 1 at grid 3 is of the order of 1 to 5 μm, for example 3.5 µm, and the thickness of each additional grid 15, 16 or 17 is around 50 µm.

    Un avantage de la présente invention est qu'elle permet de réaliser un écran plat de visualisation à haute tension inter-électrodes sans nécessiter le recours à des composants de commutation haute tension, la sélection de la couleur à afficher étant effectuée par la structure 14 de grilles additionnelles à basse tension.An advantage of the present invention is that it allows to produce a high-voltage inter-electrode display screen without the need for switching components high voltage, the selection of the color to be displayed being performed by the structure 14 of additional grids at low voltage.

    Un autre avantage de la présente invention est qu'elle garantit une focalisation optimale des électrons vers les sous-pixels de la couleur correspondante.Another advantage of the present invention is that it guarantees optimal focusing of electrons towards the sub-pixels of the corresponding color.

    A titre de variante de réalisation, les colonnes 13 de la cathode 1 peuvent être subdivisées en sous-colonnes adressées indépendamment les unes des autres. Dans ce cas, la sélection de la couleur s'effectue au moyen des sous-colonnes de la cathode. La structure 14 de grilles additionnelles a alors pour rôle de garantir une focalisation optimale des électrons et de permettre une haute tension inter-électrodes.As an alternative embodiment, the columns 13 of cathode 1 can be subdivided into addressed sub-columns independently of each other. In this case, selecting the color is carried out by means of the cathode sub-columns. The structure 14 of additional grids then has the role of guarantee optimal focusing of electrons and allow a high inter-electrode voltage.

    Un autre avantage de la présente invention est qu'en permettant la polarisation de l'anode sous une tension élevée, on peut désormais utiliser des éléments luminophores du type de ceux utilisés dans des tubes cathodiques de télévision couleur dont les techniques de fabrication sont parfaitement maítrisées.Another advantage of the present invention is that allowing the polarization of the anode under a high voltage, we can now use phosphor elements like those used in color television cathode ray tubes including the manufacturing techniques are perfectly mastered.

    Un autre avantage de la présente invention est qu'en permettant la réalisation d'une anode dont les éléments luminophores sont tous polarisés simultanément, les bandes alternées d'éléments luminophores utilisées classiquement dans les écrans à micropointes peuvent être remplacées par des pastilles d'éléments luminophores de chaque couleur correspondant à chaque sous-pixel.Another advantage of the present invention is that allowing the production of an anode whose phosphor elements are all polarized simultaneously, the alternating bands phosphor elements conventionally used in screens with microtips can be replaced with element pellets phosphors of each color corresponding to each sub-pixel.

    La figure 4 est une vue de dessus d'une structure de grilles additionnelles selon la présente invention destinée à être associée à une anode portant trois pastilles d'éléments luminophores de couleurs différentes pour chaque pixel.Figure 4 is a top view of a structure of additional grids according to the present invention intended for be associated with an anode carrying three pellets of elements phosphors of different colors for each pixel.

    Les orifices 19 à 23 de la structure 14 sont alors disposés, pour chaque pixel défini par l'intersection d'une ligne 25 de la grille 3 et d'une colonne 13 de la cathode 1, en fonction de la disposition, côté anode, des pastilles d'éléments luminophores (non représentées).The holes 19 to 23 of the structure 14 are then arranged, for each pixel defined by the intersection of a line 25 of grid 3 and a column 13 of cathode 1, in depending on the arrangement, on the anode side, of the element pellets phosphors (not shown).

    Dans le mode de réalisation illustré par la figure 4, les sous-pixels d'un pixel donné sont disposés de façon sensiblement triangulaire, ce qui permet d'équilibrer l'encombrement de chaque pixel dans les deux directions. On notera toutefois que la répartition des sous-pixels doit rester cohérente avec l'organisation en colonnes ou en sous-colonnes de la cathode.In the embodiment illustrated in FIG. 4, the sub-pixels of a given pixel are arranged substantially triangular, which helps balance the bulk of each pixel in both directions. However, it should be noted that the distribution of sub-pixels must remain consistent with the organization in columns or in sub-columns of the cathode.

    Bien que l'on ait fait référence dans la description qui précède à un écran couleur dont l'anode comporte trois types différents d'éléments luminophores, l'invention s'applique également au cas où l'anode est pourvue de deux types différents d'éléments luminophores, par exemple, à un écran bichrome dont les éléments luminophores sont repartis par pastilles de la taille d'un sous-pixel ou par bandes de la largeur d'un sous-pixel. Dans ce cas, seules deux grilles additionnelles selon l'invention sont prévues.Although reference was made in the description which precedes to a color screen whose anode comprises three types different from phosphor elements, the invention also applies in case the anode is provided with two different types phosphor elements, for example, to a two-color screen, the phosphor elements are distributed by pellets of the size of a sub-pixel or in strips the width of a sub-pixel. In this case, only two additional grids according to the invention are provided.

    Dans un mode de réalisation de la présente invention chaque grille additionnelle 15, 16, 17 est constituée d'une feuille métallique perforée isolée sur au moins une de ses faces. Ces feuilles sont assemblées de façon à aligner leurs ouvertures puis sont disposées sur la grille d'extraction de la plaque de cathode de l'écran. Ensuite une plaque d'anode est montée sur la grille supérieure avec interposition d'espaceurs. Néanmoins de nombreuses variantes de réalisation apparaítront à l'homme de l'art. In one embodiment of the present invention each additional grid 15, 16, 17 consists of a perforated metal sheet isolated on at least one of its faces. These sheets are assembled so as to align their openings then are arranged on the extraction grid of the plate screen cathode. Then an anode plate is mounted on the upper grid with interposition of spacers. Nevertheless many variant embodiments will appear to the man of art.

    Bien entendu, la présente invention est susceptible de diverses variantes et modifications qui apparaítront à l'homme de l'art. En particulier, la forme et le diamètre des orifices des grilles additionnelles ainsi que les potentiels respectifs d'activation et d'inhibition des grilles additionnelles seront choisis pour optimiser la focalisation vers les sous-pixels correspondants.Of course, the present invention is capable of various variants and modifications which will appear to the man of art. In particular, the shape and diameter of the orifices of the additional grids as well as the respective potentials activation and inhibition of additional grids will chosen to optimize the focusing towards the sub-pixels correspondents.

    Claims (10)

    Écran plat de visualisation couleur comportant : une cathode (1) associée à une grille (3) d'extraction d'électrons ; et une anode (5') pourvue d'au moins deux types (7r, 7g, 7b) d'éléments luminophores, tous polarisés à un même potentiel,    caractérisé en ce qu'il comporte :
       au moins deux grilles additionnelles (15, 16, 17) superposées, rapportées sur la grille d'extraction (3), isolées les unes des autres et de la grille d'extraction, et pourvues d'orifices (19, 20 ; 21, 22 ; 23, 24) coaxiaux définissant des sous-pixels (Pr, Pg, Pb) associés à chacune des couleurs, chaque grille additionnelle (15 ; 16 ; 17) étant associée à une couleur et comportant des orifices (19 ; 21 ; 23), de plus petit diamètre que les orifices coaxiaux des autres grilles additionnelles, pour activer les sous-pixels de la couleur correspondante.    Color display flat screen including: a cathode (1) associated with an electron extraction grid (3); and an anode (5 ′) provided with at least two types (7r, 7g, 7b) of phosphor elements, all polarized at the same potential, characterized in that it comprises:
    at least two additional grids (15, 16, 17) superimposed, attached to the extraction grid (3), isolated from each other and from the extraction grid, and provided with orifices (19, 20; 21, 22; 23, 24) coaxial defining sub-pixels (Pr, Pg, Pb) associated with each of the colors, each additional grid (15; 16; 17) being associated with a color and comprising orifices (19; 21; 23 ), of smaller diameter than the coaxial orifices of the other additional grids, to activate the sub-pixels of the corresponding color.         Écran selon la revendication 1, caractérisé en ce que chaque grille additionnelle (15 ; 16 ; 17) comporte deux séries d'orifices (19, 20 ; 21, 22 ; 23, 24) de diamètres différents, le diamètre des orifices (19, 21, 23) de plus petit diamètre de chaque grille additionnelle étant inférieur au diamètre des orifices de plus grand diamètre des autres grilles additionnelles.Screen according to claim 1, characterized in that each additional grid (15; 16; 17) has two series of orifices (19, 20; 21, 22; 23, 24) of different diameters, the diameter of the orifices (19, 21, 23) of smaller diameter of each additional grid being less than the diameter larger diameter holes in other grids additional. Écran selon la revendication 1 ou 2, caractérisé en ce que chaque grille additionnelle (15 ; 16 ; 17) est constituée d'une feuille métallique perforée.Screen according to claim 1 or 2, characterized in that each additional grid (15; 16; 17) is made up of a perforated metal sheet. Écran selon l'une quelconque des revendications 1 à 3, caractérisé en ce qu'il comporte des moyens pour polariser individuellement les grilles additionnelles (15, 16, 17).Screen according to any one of claims 1 to 3, characterized in that it includes means for polarizing individually the additional grids (15, 16, 17). Procédé de commande d'un écran plat de visualisation couleur selon l'une quelconque des revendications 1 à 4, caractérisé en ce qu'il consiste à polariser séquentiellement chaque grille additionnelle (15 ; 16 ; 17) à un potentiel respectif d'activation des sous-pixels (Pr ; Pg ; Pb) de la couleur correspondante, les autres grilles additionnelles étant portées à des potentiels respectifs d'inhibition des sous-pixels des couleurs correspondantes.Method for controlling a flat display screen color according to any one of claims 1 to 4, characterized in that it consists in sequentially polarizing each additional grid (15; 16; 17) at a respective potential activation of the sub-pixels (Pr; Pg; Pb) of the corresponding color, the other additional grids being brought to respective inhibitory potentials of the color sub-pixels corresponding. Procédé de commande selon la revendication 5, caractérisé en ce que les potentiels respectifs d'activation des grilles additionnelles (15, 16, 17) sont positifs ou nuls, leurs potentiels respectifs d'inhibition étant inférieurs à un potentiel minimal de polarisation de la cathode (1).Control method according to claim 5, characterized in that the respective activation potentials of additional grids (15, 16, 17) are positive or zero, their respective inhibition potentials being less than a potential minimum cathode polarization (1). Procédé de commande selon la revendication 5 ou 6, caractérisé en ce que le potentiel d'activation de chaque grille additionnelle (15, 16, 17) est choisi en fonction du diamètre de ses orifices (19, 21, 23) de plus petit diamètre.Control method according to claim 5 or 6, characterized in that the activation potential of each grid additional (15, 16, 17) is chosen according to the diameter of its orifices (19, 21, 23) of smaller diameter. Procédé de commande selon l'une quelconque des revendications 5 à 7, caractérisé en ce que le potentiel d'activation de chaque grille additionnelle (15, 16, 17) est choisi en fonction de la distance qui sépare cette grille additionnelle (15, 16, 17) de la grille d'extraction (3).Control method according to any one of claims 5 to 7, characterized in that the activation potential of each additional grid (15, 16, 17) is chosen by function of the distance between this additional grid (15, 16, 17) of the extraction grid (3). Procédé de commande selon l'une quelconque des revendication 5 à 8, caractérisé en ce que les potentiels respectifs d'inhibition des grilles additionnelles (15, 16, 17) sont identiques.Control method according to any one of claim 5 to 8, characterized in that the respective potentials inhibition of the additional grids (15, 16, 17) are identical. Procédé de commande selon l'une quelconque des revendications 5 à 9, caractérisé en ce que le potentiel de polarisation des éléments luminophores (7r, 7g, 7b) de l'anode (5') est compris entre 2 et 10 keV.Control method according to any one of claims 5 to 9, characterized in that the bias potential phosphor elements (7r, 7g, 7b) of the anode (5 ') is between 2 and 10 keV.
    EP97410133A 1996-11-22 1997-11-21 Flat panel display with focusing gates Withdrawn EP0844642A1 (en)

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    FR9614615 1996-11-22
    FR9614615A FR2756417A1 (en) 1996-11-22 1996-11-22 FLAT VISUALIZATION SCREEN WITH FOCUSING GRIDS

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    EP0844642A1 true EP0844642A1 (en) 1998-05-27

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    JPH10326582A (en) 1998-12-08
    FR2756417A1 (en) 1998-05-29

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