EP0649162A1 - Flat cold cathode display with switched anode - Google Patents

Flat cold cathode display with switched anode Download PDF

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Publication number
EP0649162A1
EP0649162A1 EP94410089A EP94410089A EP0649162A1 EP 0649162 A1 EP0649162 A1 EP 0649162A1 EP 94410089 A EP94410089 A EP 94410089A EP 94410089 A EP94410089 A EP 94410089A EP 0649162 A1 EP0649162 A1 EP 0649162A1
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EP
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Prior art keywords
groups
bands
phosphor elements
cathode
anode
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EP94410089A
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German (de)
French (fr)
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EP0649162B1 (en
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Michel Garcia
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Pixel International SA
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Pixel International SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/08—Electrodes intimately associated with a screen on or from which an image or pattern is formed, picked-up, converted or stored, e.g. backing-plates for storage tubes or collecting secondary electrons
    • H01J29/085—Anode plates, e.g. for screens of flat panel displays

Definitions

  • the present invention relates to a flat display screen with microtips. It applies more particularly to the production of a cathodoluminescent anode of such a screen and, in particular, connections of luminescent elements of the anode for operation as a switched anode.
  • Figures 1 and 2 show, respectively in section and in perspective, the structure of a flat screen with microtips of the type to which the invention relates.
  • Such a microtip screen essentially consists of a cathode 11 with microtips 10 and a grid 5 provided with holes at the locations of the microtips.
  • the cathode 11 is placed opposite a cathodoluminescent anode 12 including a glass substrate 2 constitutes the screen surface.
  • the cathode 11 consists, on a glass substrate 1, of cathode conductors 3 organized in columns. These cathode conductors 3 are generally coated with a resistive layer (not shown) for homogenizing the electronic emission.
  • the cathode 11 is associated with the grid 5 with interposition of an insulating layer 4 to isolate the cathode conductors 3 from the grid 5. Holes are respectively made in the grid 5 and insulation 4 layers to receive the microtips 10 which are formed on the resistive layer.
  • the grid 5 is organized in rows L1, L2, L3, the intersection of a row L of the grid 5 and a column 3 of the cathode 11, defining a pixel. For reasons of clarity, only a few microtips 10 have been shown in FIG. 2 at the intersection of a row L and a column 3. In practice, these microtips 10 are several thousand per screen pixel .
  • This device uses the electric field created between the cathode 11 and the grid 5 so that electrons are extracted from the microtips 10 towards phosphor elements 8 of the anode 12 by crossing an empty space 6.
  • the anode 12 is provided with alternating bands of phosphor elements 8 each corresponding to a color (Blue, Red, Green). Each strip is electrically isolated from the two neighboring strips.
  • the phosphor elements 8 are deposited on electrodes 7, made up of corresponding strips of a transparent conductive layer such as indium tin oxide (ITO).
  • ITO indium tin oxide
  • the strips are arranged parallel to the cathode columns 3, a group of three strips (one per color) being opposite a cathode column.
  • the width of a group of bands of the anode 12 corresponds to the width of a pixel.
  • the sets of blue, red and green bands are selectively polarized with respect to the cathode 11, so that the electrons extracted from the microtips 10 of a pixel of the cathode / grid are selectively directed towards the phosphor elements 8 opposite each colours.
  • the display of an image takes place during a frame time (for example 20 ms) by suitably polarizing the anode 12, the cathode 11 and the grid 5 by means of the control electronics.
  • the bands of phosphor elements 8 of the anode 12 are sequentially polarized by sets of bands of the same color, that is to say for a duration of sub-frame corresponding to one third of the frame time (for example 6.6 ms).
  • the display is carried out line by line, sequentially polarizing the grid rows during a "line time" during which each cathode column is brought to a potential which is a function of the brightness of the pixel to be displayed along the row current in the considered color.
  • the polarization of the columns 3 of the cathode 11 changes with each new row of the line scan.
  • a "line time” (for example 13.7 ⁇ s) corresponds to the duration of a subframe divided by the number of grid rows.
  • the sets of bands of phosphor elements 8 are therefore sequentially brought to a potential making it possible to attract the electrons emitted by the microtips 10.
  • This potential is a function of the distance (empty space 6) which separates the cathode / grid from the anode and is for example greater than 250 V.
  • the grid rows are sequentially polarized during a subframe. A given row L is brought to a potential (for example 80 V) while the other rows are at zero potential during the "line time" of the current row.
  • the cathode columns, the potential of which represents on each line the brightness of the pixel defined by the intersection of column 3 and row L in the color considered, are brought to respective potentials between a maximum emission potential and a potential for no emission (for example 0 and 30 V respectively).
  • the choice of the values of the polarization potentials is linked to the characteristics of the phosphor elements 8 and of the microtips 10. Conventionally, below a potential difference of 50 V between the cathode and the grid, there is no electronic emission and, the maximum emission used corresponds to a potential difference of 80 V.
  • a drawback of conventional screens lies in the fact that the electrons emitted by microtips 10 of a given column 3 of the cathode 11 tend to excite the strips of phosphors 8 of the same color which are opposite the two neighboring columns 3. Indeed, although two bands of the same color are separated by two bands of another color, the distance (of the order of 0.2 mm) between the phosphor elements 8 and the microtips 10 leads to the fact that the electrons have tendency to deviate to the nearest bands of the same color. This phenomenon of illumination of neighboring pixels is increased in the event of misalignment of the groups of bands of phosphor elements 8 with respect to the cathode columns, which can occur during assembly of the screen.
  • anode 12 In the case of a monochrome screen, the simplest way to produce an anode 12 is to deposit, over the entire substrate 2 of the anode 12, a conductor 7 coated with phosphors 8 without discontinuity. The anode 12 is permanently polarized. The selection of the areas of the screen excited by the electrons emitted by the microtips 10 is controlled by the respective polarizations of the cathode columns and of the grid rows. The drawbacks of color screens are found even more significantly in such monochrome screens.
  • the present invention aims to overcome these drawbacks by proposing a flat display screen which has good definition and good proximity contrast.
  • the present invention provides a flat display screen of the type comprising a cathode with electronic emission microtips organized in columns, a grid organized in rows and an anode provided with phosphor elements organized in groups of juxtaposed bands. and electrically isolated from each other.
  • the intersection of a row of the grid and a column of the cathode defines a pixel of the screen.
  • the groups of anode bands are electrically connected in two networks, a first network comprising the groups of bands of odd rank, while a second network comprises the groups of bands of even rank.
  • the screen includes control electronics suitable for sequentially addressing groups of odd, respectively even rank.
  • the groups of bands of phosphor elements are parallel to the columns of the cathode and have a width substantially identical to the width of these columns.
  • the cathode columns are addressed individually by the control electronics into two networks corresponding to the connection networks of the groups of bands of the anode.
  • control electronics include an inverter for addressing the connection networks of the groups of bands of phosphor elements.
  • the groups of bands of phosphor elements are parallel to the rows of the grid and have a width substantially identical to the width of these rows.
  • control electronics comprises means for sequentially addressing the rows of grid of even rank, respectively odd, at the same time as it addresses the groups of bands of phosphor elements of even rank , respectively odd.
  • each of said groups consists of a strip of phosphor elements, the phosphor elements of all the groups being of the same type.
  • each of said groups consists of three bands of phosphor elements of different colors, each network comprising three sets of bands of phosphor elements electrically connected together, and the control electronics comprising means for individually addressing each set of the same network.
  • the essential characteristic of the present invention resides in the electrical interconnection of the strips of phosphor elements of the anode. These bands are no longer interconnected by color, but in two networks (R1, V1, B1; R2, V2, B2) of bands by color.
  • a given band (for example B1) is not only electrically isolated from all the bands of the other two colors (for example R1, V1, R2, V2) but also from two bands of the same color which are closest to it (for example B2).
  • the bands of two neighboring groups 13, 14 are each connected to a different network.
  • This interconnection structure of the bands of phosphor elements 8 of the anode 12 is accompanied by a sequential addressing of the two arrays of bands to each image frame, in addition to the sequential addressing of the bands of the same color belonging to the same network.
  • the display of an image is always carried out for a frame time (for example 20 ms) by means of control electronics (not shown).
  • a frame time for example 20 ms
  • the bands of phosphor elements 8 of the anode 12 are sequentially polarized by sets of bands of the same color, but network by network.
  • a frame is therefore divided into six sub-frames of duration (for example 3.3 ms) corresponding to one sixth of the frame time.
  • the display is always done line by line by sequentially polarizing the rows L of the grid 5. But here, each row L is polarized six times for a given frame, the sequential polarization of all the rows L being repeated for each sub- frame.
  • the addressing of the cathode columns is also modified to reproduce, on the cathode side, a sequential addressing of two arrays of columns 3 similar to the arrays formed on the anode side 12.
  • an inverter or a simple jumper to reverse the order of the networks of the anode 12 in their sequential operation controlled by the control electronics.
  • Such an inverter or jumper will, for example, be positioned once and for all during the test of the screen after it has been assembled.
  • the invention allows the electrons emitted by the microtips 10 of the cathode 11 to be attracted to a polarized strip of phosphor elements 8 of the anode 12 (for example R2), without the possibility for the electrons to be picked up by the strips of the same color (for example R1) of the two neighboring groups 13.
  • the first embodiment according to the invention makes it possible to considerably improve the proximity contrast of the screen .
  • the invention also makes it possible to increase the anode-cathode distance 6.
  • the short distance 6, necessary for the collection of electrons on a single anode strip in conventional screens limits the anode voltage -cathode to avoid the formation of electric arcs which would destroy the screen.
  • the invention therefore makes it possible, by authorizing the increase in the inter-electrode distance without harming the collection of electrons, to apply to the anode 12 a higher potential for increasing the brightness of the screen.
  • the invention also allows the reduction of the size of the pixels to improve the resolution of the screen.
  • FIG. 4 illustrates the application of the first embodiment according to the invention to a monochrome screen.
  • the technique of color screens is applied, namely, the deposition of the phosphors 8 on parallel conductive strips electrically isolated from each other, but the phosphors are here all of the same type insofar as it is a monochrome screen .
  • the bands are interconnected in two networks (I, P), two neighboring bands each being connected to one of the two networks.
  • the width of a strip corresponds to the width of a pixel defined, as above, by the intersection of a cathode column with a row of grids. Columns 3 and rows L have been symbolized by dotted lines in FIG. 4.
  • FIG. 5 represents a second embodiment of the invention which makes it possible to reduce the number of switches of the columns 3 of the cathode 11 to the same value as that of conventional screens and thus limit the consumption of the control electronics.
  • the strips of phosphor elements 8 carried by the conductors 7 of the anode 12 are now parallel to the rows of the grid 5.
  • a pixel is always defined by the intersection of a row L of the grid 5 and of a column 3 of the cathode 11, and the width of a group of bands (R, G, B) of the anode 12 corresponds to the width of a row of the grid 5.
  • the respective polarizations of the cathode 11, the anode 12 and the grid 5 are here provided by the control electronics in the following manner.
  • the display of an image is always carried out during a frame time (for example 20 ms).
  • the bands of phosphor elements 8 of the anode 12 are sequentially polarized by color and, inside each set of color bands, by network.
  • the bands of even (or odd) rank of a first color are polarized, then the bands of odd (or even) rank of this first color. Then it is the turn of the odd (or even) rows of the second color, and so on.
  • the display is always done line by line, sequentially polarizing the grid rows, but every other line.
  • a first sequence of a sub-frame which corresponds to the polarization of the bands of the first network of a color (ie a half-frame)
  • the rows of odd rank or even
  • the polarization of the cathode 11 again becomes similar to that of conventional screens. That is to say that during each "line time" which corresponds to the polarization of a grid row during the line scanning, all the cathode columns are brought to a potential which is a function of the brightness of the pixel at display along the current line in the color considered.
  • the number of line scans is divided by two with respect to the first embodiment.
  • the number of switches of the cathode 11 which are the most current consuming within the control electronics is therefore divided by two, compared with the first embodiment. Indeed, while in the first embodiment, all the grid rows are sequentially polarized six times per frame (once for each of the six sub-frames), they are now only polarized three times per frame.
  • anode voltage can now be higher, to increase the anode / cathode space 6 and have recourse to a thin aluminum film affixed to the phosphor elements 8.
  • the increase in energy of the electrons allows them to pass through this thin film of aluminum.

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Abstract

The invention relates to a flat display screen of the type including a micropoint electron emission cathode organised in columns (3), a grid organised in rows (L) and an anode provided with a luminophor element (8) which are arranged in groups (13, 14) of juxtaposed bands which are electrically insulated from each other, the intersection of a row (L) of the grid and a column (3) of the cathode defining a pixel of the screen; the groups (13, 14) of bands (8) of the anode are electrically connected in two networks, a first network comprising the groups (13) of bands of odd rank (R1, V1, B1), whereas a second network comprises the groups (14) of bands of even rank (R2, V2, B2); and the screen is associated with control electronics capable of sequentially addressing the groups of odd rank and even rank, respectively. <IMAGE>

Description

La présente invention concerne un écran plat de visualisation à micropointes. Elle s'applique plus particulièrement à la réalisation d'une anode cathodoluminescente d'un tel écran et, en particulier, des connexions d'éléments luminescents de l'anode pour un fonctionnement en anode commutée.The present invention relates to a flat display screen with microtips. It applies more particularly to the production of a cathodoluminescent anode of such a screen and, in particular, connections of luminescent elements of the anode for operation as a switched anode.

Les figures 1 et 2 représentent, respectivement en coupe et en perspective cavalière, la structure d'un écran plat à micropointes du type auquel se rapporte l'invention.Figures 1 and 2 show, respectively in section and in perspective, the structure of a flat screen with microtips of the type to which the invention relates.

Un tel écran à micropointes est essentiellement constitué d'une cathode 11 à micropointes 10 et d'une grille 5 pourvue de trous aux emplacements des micropointes 10. La cathode 11 est placée en regard d'une anode cathodoluminescente 12 dont un substrat de verre 2 constitue la surface d'écran.Such a microtip screen essentially consists of a cathode 11 with microtips 10 and a grid 5 provided with holes at the locations of the microtips. The cathode 11 is placed opposite a cathodoluminescent anode 12 including a glass substrate 2 constitutes the screen surface.

Le principe de fonctionnement et le détail de la constitution d'un tel écran à micropointes sont décrits dans le brevet américain numéro 4 940 916 du Commissariat à l'Energie Atomique.The operating principle and the detail of the constitution of such a microtip screen are described in American patent number 4 940 916 of the French Atomic Energy Commission.

La cathode 11 est constituée, sur un substrat de verre 1, de conducteurs de cathode 3 organisés en colonnes. Ces conducteurs de cathode 3 sont généralement revêtus d'une couche résistive (non représentée) d'homogénéisation de l'émission électronique. La cathode 11 est associée à la grille 5 avec interposition d'une couche isolante 4 pour isoler les conducteurs de cathode 3 de la grille 5. Des trous sont respectivement pratiqués dans les couches de grille 5 et d'isolement 4 pour recevoir les micropointes 10 qui sont formées sur la couche résistive. La grille 5 est organisée en rangées L1, L2, L3, l'intersection d'une rangée L de la grille 5 et d'une colonne 3 de la cathode 11, définissant un pixel. Pour des raisons de clarté, seules quelques micropointes 10 ont été représentées à la figure 2 à l'intersection d'une rangée L et d'une colonne 3. En pratique, ces micropointes 10 sont au nombre de plusieurs milliers par pixel d'écran.The cathode 11 consists, on a glass substrate 1, of cathode conductors 3 organized in columns. These cathode conductors 3 are generally coated with a resistive layer (not shown) for homogenizing the electronic emission. The cathode 11 is associated with the grid 5 with interposition of an insulating layer 4 to isolate the cathode conductors 3 from the grid 5. Holes are respectively made in the grid 5 and insulation 4 layers to receive the microtips 10 which are formed on the resistive layer. The grid 5 is organized in rows L1, L2, L3, the intersection of a row L of the grid 5 and a column 3 of the cathode 11, defining a pixel. For reasons of clarity, only a few microtips 10 have been shown in FIG. 2 at the intersection of a row L and a column 3. In practice, these microtips 10 are several thousand per screen pixel .

Ce dispositif utilise le champ électrique créé entre la cathode 11 et la grille 5 pour que des électrons soient extraits des micropointes 10 vers des éléments luminophores 8 de l'anode 12 en traversant un espace vide 6.This device uses the electric field created between the cathode 11 and the grid 5 so that electrons are extracted from the microtips 10 towards phosphor elements 8 of the anode 12 by crossing an empty space 6.

Dans le cas d'un écran couleur, l'anode 12 est pourvue de bandes alternées d'éléments luminophores 8 correspondant chacune à une couleur (Bleu, Rouge, Vert). Chaque bande est électriquement isolée des deux bandes qui lui sont voisines. Les éléments luminophores 8 sont déposés sur des électrodes 7, constituées de bandes correspondantes d'une couche conductrice transparente telle que de l'oxyde d'indium et d'étain (ITO). Les bandes sont disposées parallèlement aux colonnes 3 de cathode, un groupe de trois bandes (une par couleur) étant en regard d'une colonne de cathode. Ainsi, la largeur d'un groupe de bandes de l'anode 12 correspond à la largeur d'un pixel. Les ensembles de bandes bleues, rouges, vertes sont sélectivement polarisés par rapport à la cathode 11, pour que les électrons extraits des micropointes 10 d'un pixel de la cathode/grille soient sélectivement dirigés vers les éléments luminophores 8 en vis à vis de chacune des couleurs.In the case of a color screen, the anode 12 is provided with alternating bands of phosphor elements 8 each corresponding to a color (Blue, Red, Green). Each strip is electrically isolated from the two neighboring strips. The phosphor elements 8 are deposited on electrodes 7, made up of corresponding strips of a transparent conductive layer such as indium tin oxide (ITO). The strips are arranged parallel to the cathode columns 3, a group of three strips (one per color) being opposite a cathode column. Thus, the width of a group of bands of the anode 12 corresponds to the width of a pixel. The sets of blue, red and green bands are selectively polarized with respect to the cathode 11, so that the electrons extracted from the microtips 10 of a pixel of the cathode / grid are selectively directed towards the phosphor elements 8 opposite each colours.

Classiquement, toutes les bandes d'une même couleur sont électriquement reliées ensemble, à l'extérieur de la surface utile de l'écran, à une électronique de commande (non représentée). Côté cathode 11, chaque colonne de cathode et chaque rangée de grille est individuellement reliée à l'électronique de commande.Conventionally, all the strips of the same color are electrically connected together, outside the useful surface of the screen, to control electronics (not shown). Cathode side 11, each cathode column and each row of grid is individually connected to the control electronics.

L'affichage d'une image s'effectue pendant un temps de trame (par exemple 20 ms) en polarisant convenablement l'anode 12, la cathode 11 et la grille 5 au moyen de l'électronique de commande. Durant une trame, les bandes d'éléments luminophores 8 de l'anode 12 sont séquentiellement polarisés par ensembles de bandes d'une même couleur, soit pendant une durée de sous-trame correspondant au tiers du temps de trame (par exemple 6,6 ms). L'affichage s'effectue ligne par ligne, en polarisant séquentiellement les rangées de grille pendant un "temps de ligne" durant lequel chaque colonne de cathode est portée à un potentiel qui est fonction de la brillance du pixel à afficher le long de la rangée courante dans la couleur considérée. La polarisation des colonnes 3 de la cathode 11 change à chaque nouvelle rangée du balayage ligne. Un "temps de ligne" (par exemple 13,7 µs) correspond à la durée d'une sous-trame divisée par le nombre de rangées de grille.The display of an image takes place during a frame time (for example 20 ms) by suitably polarizing the anode 12, the cathode 11 and the grid 5 by means of the control electronics. During a frame, the bands of phosphor elements 8 of the anode 12 are sequentially polarized by sets of bands of the same color, that is to say for a duration of sub-frame corresponding to one third of the frame time (for example 6.6 ms). The display is carried out line by line, sequentially polarizing the grid rows during a "line time" during which each cathode column is brought to a potential which is a function of the brightness of the pixel to be displayed along the row current in the considered color. The polarization of the columns 3 of the cathode 11 changes with each new row of the line scan. A "line time" (for example 13.7 µs) corresponds to the duration of a subframe divided by the number of grid rows.

Les ensembles de bandes d'éléments luminophores 8 sont donc séquentiellement portés à un potentiel permettant d'attirer les électrons émis par les micropointes 10. Ce potentiel est fonction de la distance (espace vide 6) qui sépare la cathode/grille de l'anode et est par exemple supérieur à 250 V. Les rangées de grille sont séquentiellement polarisées pendant une sous-trame. Une rangée L donnée est portée à un potentiel (par exemple 80 V) alors que les autres rangées sont à un potentiel nul pendant le "temps de ligne" de la rangée courante. Les colonnes de cathode, dont le potentiel représente à chaque ligne la brillance du pixel défini par l'intersection de la colonne 3 et de la rangée L dans la couleur considérée, 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 V). Le choix des valeurs des potentiels de polarisation est lié aux caractéristiques des éléments luminophores 8 et des micropointes 10. Classiquement, en dessous d'une différence de potentiel de 50 V entre la cathode et la grille, il n'y a pas d'émission électronique et, l'émission maximale utilisée correspond à une différence de potentiel de 80 V.The sets of bands of phosphor elements 8 are therefore sequentially brought to a potential making it possible to attract the electrons emitted by the microtips 10. This potential is a function of the distance (empty space 6) which separates the cathode / grid from the anode and is for example greater than 250 V. The grid rows are sequentially polarized during a subframe. A given row L is brought to a potential (for example 80 V) while the other rows are at zero potential during the "line time" of the current row. The cathode columns, the potential of which represents on each line the brightness of the pixel defined by the intersection of column 3 and row L in the color considered, are brought to respective potentials between a maximum emission potential and a potential for no emission (for example 0 and 30 V respectively). The choice of the values of the polarization potentials is linked to the characteristics of the phosphor elements 8 and of the microtips 10. Conventionally, below a potential difference of 50 V between the cathode and the grid, there is no electronic emission and, the maximum emission used corresponds to a potential difference of 80 V.

Un inconvénient des écrans classiques réside dans le fait que les électrons émis par des micropointes 10 d'une colonne 3 donnée de la cathode 11 ont tendance à exciter les bandes de luminophores 8 de même couleur qui sont en regard des deux colonnes 3 voisines. En effet, bien que deux bandes de même couleur soient séparées par deux bandes d'une autre couleur, la distance (de l'ordre de 0,2 mm) entre les éléments luminophores 8 et les micropointes 10 conduit à ce que les électrons ont tendance à dévier vers les bandes de même couleur les plus proches. Ce phénomène d'éclairement des pixels voisins est accru en cas de désalignement des groupes de bandes d'éléments luminophores 8 par rapport aux colonnes de cathode, ce qui peut se produire lors de l'assemblage de l'écran.A drawback of conventional screens lies in the fact that the electrons emitted by microtips 10 of a given column 3 of the cathode 11 tend to excite the strips of phosphors 8 of the same color which are opposite the two neighboring columns 3. Indeed, although two bands of the same color are separated by two bands of another color, the distance (of the order of 0.2 mm) between the phosphor elements 8 and the microtips 10 leads to the fact that the electrons have tendency to deviate to the nearest bands of the same color. This phenomenon of illumination of neighboring pixels is increased in the event of misalignment of the groups of bands of phosphor elements 8 with respect to the cathode columns, which can occur during assembly of the screen.

Dans le cas d'un écran monochrome, la manière la plus simple de réaliser une anode 12 consiste à déposer, sur tout le substrat 2 de l'anode 12, un conducteur 7 revêtu de luminophores 8 sans discontinuité. L'anode 12 est polarisée en permanence. La sélection des zones de l'écran excitées par les électrons émis par les micropointes 10 est commandée par les polarisations respectives des colonnes de cathode et des rangées de grille. Les inconvénients des écrans couleurs se retrouvent de manière encore plus significative dans de tels écrans monochromes.In the case of a monochrome screen, the simplest way to produce an anode 12 is to deposit, over the entire substrate 2 of the anode 12, a conductor 7 coated with phosphors 8 without discontinuity. The anode 12 is permanently polarized. The selection of the areas of the screen excited by the electrons emitted by the microtips 10 is controlled by the respective polarizations of the cathode columns and of the grid rows. The drawbacks of color screens are found even more significantly in such monochrome screens.

La présente invention vise à pallier ces inconvénients en proposant un écran plat de visualisation qui présente une bonne définition et un bon contraste de proximité.The present invention aims to overcome these drawbacks by proposing a flat display screen which has good definition and good proximity contrast.

Pour atteindre cet objet, la présente invention prévoit un écran plat de visualisation du type comportant une cathode à micropointes d'émission électronique organisée en colonnes, une grille organisée en rangées et une anode pourvue d'éléments luminophores organisés en groupes de bandes juxtaposées et électriquement isolées entre elles. L'intersection d'une rangée de la grille et d'une colonne de la cathode définit un pixel de l'écran. Les groupes de bandes de l'anode sont électriquement connectés en deux réseaux, un premier réseau comprenant les groupes de bandes de rang impair, tandis qu'un second réseau comprend les groupes de bandes de rang pair. L'écran comporte une électronique de commande propre à adresser séquentiellement les groupes de rang impair, respectivement pair.To achieve this object, the present invention provides a flat display screen of the type comprising a cathode with electronic emission microtips organized in columns, a grid organized in rows and an anode provided with phosphor elements organized in groups of juxtaposed bands. and electrically isolated from each other. The intersection of a row of the grid and a column of the cathode defines a pixel of the screen. The groups of anode bands are electrically connected in two networks, a first network comprising the groups of bands of odd rank, while a second network comprises the groups of bands of even rank. The screen includes control electronics suitable for sequentially addressing groups of odd, respectively even rank.

Selon un mode de réalisation de l'invention, les groupes de bandes d'éléments luminophores sont parallèles aux colonnes de la cathode et présentent une largeur sensiblement identique à la largeur de ces colonnes.According to one embodiment of the invention, the groups of bands of phosphor elements are parallel to the columns of the cathode and have a width substantially identical to the width of these columns.

Selon un mode de réalisation de l'invention, les colonnes de la cathode sont adressées individuellement par l'électronique de commande en deux réseaux correspondant aux réseaux de connexion des groupes de bandes de l'anode.According to one embodiment of the invention, the cathode columns are addressed individually by the control electronics into two networks corresponding to the connection networks of the groups of bands of the anode.

Selon un mode de réalisation de l'invention, l'électronique de commande comporte un inverseur de l'adressage des réseaux de connexion des groupes de bandes d'éléments luminophores.According to one embodiment of the invention, the control electronics include an inverter for addressing the connection networks of the groups of bands of phosphor elements.

Selon un mode de réalisation de l'invention, les groupes de bandes d'éléments luminophores sont parallèles aux rangées de la grille et présentent une largeur sensiblement identique à la largeur de ces rangées.According to one embodiment of the invention, the groups of bands of phosphor elements are parallel to the rows of the grid and have a width substantially identical to the width of these rows.

Selon un mode de réalisation de l'invention, l'électronique de commande comporte des moyens pour adresser séquentiellement les rangées de grille de rang pair, respectivement impair, en même temps qu'elle adresse les groupes de bandes d'éléments luminophores de rang pair, respectivement impair.According to one embodiment of the invention, the control electronics comprises means for sequentially addressing the rows of grid of even rank, respectively odd, at the same time as it addresses the groups of bands of phosphor elements of even rank , respectively odd.

Selon un mode de réalisation de l'invention, chacun desdits groupes est constitué d'une bande d'éléments luminophores, les éléments luminophores de tous les groupes étant d'un même type.According to one embodiment of the invention, each of said groups consists of a strip of phosphor elements, the phosphor elements of all the groups being of the same type.

Selon un mode de réalisation de l'invention, chacun desdits groupes est constitué de trois bandes d'éléments luminophores de couleurs différentes, chaque réseau comportant trois ensembles de bandes d'éléments luminophores électriquement connectées entre elles, et l'électronique de commande comportant des moyens pour adresser individuellement chaque ensemble d'un même réseau.According to one embodiment of the invention, each of said groups consists of three bands of phosphor elements of different colors, each network comprising three sets of bands of phosphor elements electrically connected together, and the control electronics comprising means for individually addressing each set of the same network.

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 :

  • les figures 1 et 2 qui ont été décrites précédemment sont destinées à exposer l'état de la technique et le problème posé ;
  • la figure 3 représente schématiquement en élévation, une anode d'écran plat selon un premier mode de réalisation de l'invention appliqué à un écran couleur ;
  • la figure 4 représente schématiquement, une anode d'écran plat selon le premier mode de réalisation de l'invention appliqué à un écran monochrome ; et
  • la figure 5 représente schématiquement en coupe, un écran plat de visualisation selon un second mode de réalisation de l'invention appliqué à un écran couleur.
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:
  • Figures 1 and 2 which have been described above are intended to show the state of the art and the problem posed;
  • Figure 3 shows schematically in elevation, a flat screen anode according to a first embodiment of the invention applied to a color screen;
  • FIG. 4 schematically represents a flat screen anode according to the first embodiment of the invention applied to a monochrome screen; and
  • FIG. 5 schematically shows in section, a flat display screen according to a second embodiment of the invention applied to a color screen.

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

Comme le montre la figure 3, la caractéristique essentielle de la présente invention réside dans l'interconnexion électrique des bandes d'éléments luminophores de l'anode. Ces bandes ne sont plus désormais interconnectées par couleur, mais en deux réseaux (R1, V1, B1 ; R2, V2, B2) de bandes par couleur. Une bande donnée (par exemple B1) est non seulement électriquement isolée de toutes les bandes des deux autres couleurs (par exemple R1, V1, R2, V2) mais également des deux bandes de même couleur qui lui sont les plus proches (par exemple B2). En d'autres termes, les bandes de deux groupes 13, 14 voisins sont chacune connectées à un réseau différent.As shown in FIG. 3, the essential characteristic of the present invention resides in the electrical interconnection of the strips of phosphor elements of the anode. These bands are no longer interconnected by color, but in two networks (R1, V1, B1; R2, V2, B2) of bands by color. A given band (for example B1) is not only electrically isolated from all the bands of the other two colors (for example R1, V1, R2, V2) but also from two bands of the same color which are closest to it (for example B2). In other words, the bands of two neighboring groups 13, 14 are each connected to a different network.

A la figure 3, les colonnes 3 de la cathode 11 et les rangées L de la grille 5 ont été symbolisées en pointillés, la largeur d'un groupe 13, 14 correspondant à la largeur d'une colonne 3.In FIG. 3, the columns 3 of the cathode 11 and the rows L of the grid 5 have been symbolized in dotted lines, the width of a group 13, 14 corresponding to the width of a column 3.

Cette structure d'interconnexion des bandes d'éléments luminophores 8 de l'anode 12 s'accompagne d'un adressage séquentiel des deux réseaux de bandes à chaque trame d'image, en plus de l'adressage séquentiel des bandes d'une même couleur appartenant à un même réseau.This interconnection structure of the bands of phosphor elements 8 of the anode 12 is accompanied by a sequential addressing of the two arrays of bands to each image frame, in addition to the sequential addressing of the bands of the same color belonging to the same network.

L'affichage d'une image s'effectue toujours pendant un temps de trame (par exemple 20 ms) au moyen d'une électronique de commande (non représentée). Durant une trame, les bandes d'éléments luminophores 8 de l'anode 12 sont séquentiellement polarisées par ensembles de bandes d'une même couleur, mais réseau par réseau. Une trame est donc découpée en six sous-trames d'une durée (par exemple 3,3 ms) correspondant au sixième du temps de trame.The display of an image is always carried out for a frame time (for example 20 ms) by means of control electronics (not shown). During a frame, the bands of phosphor elements 8 of the anode 12 are sequentially polarized by sets of bands of the same color, but network by network. A frame is therefore divided into six sub-frames of duration (for example 3.3 ms) corresponding to one sixth of the frame time.

L'affichage s'effectue toujours ligne par ligne en polarisant séquentiellement les rangées L de la grille 5. Mais ici, chaque rangée L est polarisée six fois pour une trame donnée, la polarisation séquentielle de toutes les rangées L étant répétée pour chaque sous-trame.The display is always done line by line by sequentially polarizing the rows L of the grid 5. But here, each row L is polarized six times for a given frame, the sequential polarization of all the rows L being repeated for each sub- frame.

On modifie également l'adressage des colonnes de cathode pour reproduire, côté cathode, un adressage séquentiel de deux réseaux de colonnes 3 similaires aux réseaux constitués côté anode 12. Ainsi, pendant chaque "temps de ligne" qui correspond à la polarisation d'une rangée L donnée de la grille 5 durant le balayage ligne, une colonne sur deux est portée à un potentiel qui est fonction de la brillance du pixel à afficher le long de la ligne courante dans la couleur considérée.The addressing of the cathode columns is also modified to reproduce, on the cathode side, a sequential addressing of two arrays of columns 3 similar to the arrays formed on the anode side 12. Thus, during each "line time" which corresponds to the polarization of a given row L of the grid 5 during the line scanning, one column out of two is brought to a potential which is a function of the brightness of the pixel to be displayed along the current line in the color considered.

On veillera cependant à ce que le réseau de colonnes de cathode, polarisé pendant une sous-trame, corresponde bien au réseau de groupes d'éléments luminophores qui lui fait face. Pour réaliser cette synchronisation, on pourra par exemple utiliser un inverseur ou un simple cavalier pour inverser l'ordre des réseaux de l'anode 12 dans leur fonctionnement séquentiel commandé par l'électronique de commande. Un tel inverseur ou cavalier sera, par exemple positionné une fois pour toutes pendant le test de l'écran après son assemblage.However, care should be taken to ensure that the network of cathode columns, polarized during a sub-frame, corresponds well to the network of groups of phosphor elements facing it. To achieve this synchronization, it is possible for example to use an inverter or a simple jumper to reverse the order of the networks of the anode 12 in their sequential operation controlled by the control electronics. Such an inverter or jumper will, for example, be positioned once and for all during the test of the screen after it has been assembled.

L'invention permet que les électrons émis par les micropointes 10 de la cathode 11 soient attirés sur une bande polarisée d'éléments luminophores 8 de l'anode 12 (par exemple R2), sans possibilité pour les électrons d'être captés par les bandes de même couleur (par exemple R1) des deux groupes 13 voisins.The invention allows the electrons emitted by the microtips 10 of the cathode 11 to be attracted to a polarized strip of phosphor elements 8 of the anode 12 (for example R2), without the possibility for the electrons to be picked up by the strips of the same color (for example R1) of the two neighboring groups 13.

Par contre, cela conduit à ce que la durée d'excitation d'un élément luminophore 8 au droit d'un pixel est divisée par deux pour respecter le temps de trame d'une image. Pour préserver à l'écran ses caractéristiques de luminosité, il faut donc le double d'intensité électrique. En effet, l'éclairement d'un élément luminophore 8 est proportionnel à sa durée d'excitation et à l'intensité du bombardement électronique.On the other hand, this leads to the fact that the duration of excitation of a phosphor element 8 in line with a pixel is halved in order to respect the frame time of an image. To preserve the brightness characteristics of the screen, you therefore need double the electrical intensity. Indeed, the illumination of a phosphor element 8 is proportional to its duration of excitation and to the intensity of the electronic bombardment.

Bien qu'il augmente la consommation en courant de l'écran et le nombre de commutation devant être effectués par l'électronique de commande, le premier mode de réalisation selon l'invention permet d'améliorer considérablement le contraste de proximité de l'écran.Although it increases the current consumption of the screen and the number of switching operations to be carried out by the control electronics, the first embodiment according to the invention makes it possible to considerably improve the proximity contrast of the screen .

Par une meilleure focalisation des électrons, l'invention permet également d'augmenter la distance anode-cathode 6. Or, la faible distance 6, nécessaire pour la collecte des électrons sur une seule bande d'anode dans les écrans classiques limite la tension anode-cathode pour éviter la formation d'arcs électriques qui détruiraient l'écran. L'invention permet donc, en autorisant l'augmentation de la distance inter-électrodes sans nuire à la collecte des électrons, d'appliquer à l'anode 12 un potentiel plus élevé pour augmenter la brillance de l'écran.By better focusing of the electrons, the invention also makes it possible to increase the anode-cathode distance 6. However, the short distance 6, necessary for the collection of electrons on a single anode strip in conventional screens limits the anode voltage -cathode to avoid the formation of electric arcs which would destroy the screen. The invention therefore makes it possible, by authorizing the increase in the inter-electrode distance without harming the collection of electrons, to apply to the anode 12 a higher potential for increasing the brightness of the screen.

L'invention autorise en outre la réduction de la taille des pixels pour améliorer la résolution de l'écran.The invention also allows the reduction of the size of the pixels to improve the resolution of the screen.

La figure 4 illustre l'application du premier mode de réalisation selon l'invention à un écran monochrome.FIG. 4 illustrates the application of the first embodiment according to the invention to a monochrome screen.

On applique la technique des écrans couleurs, à savoir, le dépôt des luminophores 8 sur des bandes conductrices parallèles électriquement isolées les unes des autres, mais les luminophores sont ici tous du même type dans la mesure où il s'agit d'un écran monochrome. Les bandes sont interconnectées en deux réseaux (I, P), deux bandes voisines étant chacune connectée à l'un des deux réseaux. S'agissant d'un écran monochrome, la largeur d'une bande correspond à la largeur d'un pixel défini, comme précédemment, par l'intersection d'une colonne de cathode avec une rangée de grille. Les colonnes 3 et les rangées L ont été symbolisées en pointillés sur la figure 4.The technique of color screens is applied, namely, the deposition of the phosphors 8 on parallel conductive strips electrically isolated from each other, but the phosphors are here all of the same type insofar as it is a monochrome screen . The bands are interconnected in two networks (I, P), two neighboring bands each being connected to one of the two networks. In the case of a monochrome screen, the width of a strip corresponds to the width of a pixel defined, as above, by the intersection of a cathode column with a row of grids. Columns 3 and rows L have been symbolized by dotted lines in FIG. 4.

On améliore ainsi considérablement le contraste et la définition des écrans monochromes.This significantly improves the contrast and definition of monochrome screens.

La figure 5 représente un second mode de réalisation de l'invention qui permet de ramener le nombre de commutations des colonnes 3 de la cathode 11 à la même valeur que celle des écrans classiques et ainsi limiter la consommation de l'électronique de commande.FIG. 5 represents a second embodiment of the invention which makes it possible to reduce the number of switches of the columns 3 of the cathode 11 to the same value as that of conventional screens and thus limit the consumption of the control electronics.

Dans ce mode de réalisation, les bandes d'éléments luminophores 8 portées par les conducteurs 7 de l'anode 12 sont désormais parallèles aux rangées de la grille 5. Un pixel est toujours défini par l'intersection d'une rangée L de la grille 5 et d'une colonne 3 de la cathode 11, et la largeur d'un groupe de bandes (R, V, B) de l'anode 12 correspond à la largeur d'une rangée de la grille 5.In this embodiment, the strips of phosphor elements 8 carried by the conductors 7 of the anode 12 are now parallel to the rows of the grid 5. A pixel is always defined by the intersection of a row L of the grid 5 and of a column 3 of the cathode 11, and the width of a group of bands (R, G, B) of the anode 12 corresponds to the width of a row of the grid 5.

L'interconnexion des bandes d'éléments luminophores est identique à celle exposée en relation avec la figure 3.The interconnection of the bands of phosphor elements is identical to that exposed in relation to FIG. 3.

Les polarisations respectives de la cathode 11, de l'anode 12 et de la grille 5 sont ici assurées par l'électronique de commande de la manière suivante.The respective polarizations of the cathode 11, the anode 12 and the grid 5 are here provided by the control electronics in the following manner.

L'affichage d'une image s'effectue toujours pendant un temps de trame (par exemple 20 ms). Durant une trame, les bandes d'éléments luminophores 8 de l'anode 12 sont séquentiellement polarisées par couleur et, à l'intérieur de chaque ensemble de bandes de couleur, par réseau. En d'autres termes, les bandes de rang pair (ou impair) d'une première couleur sont polarisées, puis les bandes de rang impair (ou pair) de cette première couleur. Ensuite, c'est au tour des bandes de rang impair (ou pair) de la deuxième couleur, et ainsi de suite.The display of an image is always carried out during a frame time (for example 20 ms). During a frame, the bands of phosphor elements 8 of the anode 12 are sequentially polarized by color and, inside each set of color bands, by network. In other words, the bands of even (or odd) rank of a first color are polarized, then the bands of odd (or even) rank of this first color. Then it is the turn of the odd (or even) rows of the second color, and so on.

L'affichage s'effectue toujours ligne par ligne en polarisant séquentiellement les rangées de grille, mais une ligne sur deux. En d'autres termes, au cours d'une première séquence d'une sous-trame qui correspond à la polarisation des bandes du premier réseau d'une couleur (soit une demi sous-trame), les rangées de rang impair (ou pair) sont séquentiellement polarisées. Puis, au cours d'une seconde séquence correspondant à la polarisation des bandes du second réseau de la même couleur (soit l'autre demi sous-trame), c'est au tour des rangées de rang pair (ou impair) d'être polarisées.The display is always done line by line, sequentially polarizing the grid rows, but every other line. In other words, during a first sequence of a sub-frame which corresponds to the polarization of the bands of the first network of a color (ie a half-frame), the rows of odd rank (or even ) are sequentially polarized. Then, during a second sequence corresponding to the polarization of the bands of the second network of the same color (ie the other half-sub-frame), it is the turn of the rows of even (or odd) rank to be polarized.

Par contre, la polarisation de la cathode 11 redevient similaire à celle des écrans classiques. C'est-à-dire que pendant chaque "temps de ligne" qui correspond à la polarisation d'une rangée de grille durant le balayage ligne, toutes les colonnes de cathode sont portées à un potentiel qui est fonction de la brillance du pixel à afficher le long de la ligne courante dans la couleur considérée. Ainsi, dans ce second mode de réalisation, on divise par deux le nombre de balayages ligne par rapport au premier mode de réalisation. On divise donc par deux le nombre de commutations de la cathode 11 qui sont les plus consommatrices de courant au sein de l'électronique de commande, par rapport au premier mode de réalisation. En effet, alors que dans le premier mode de réalisation, toutes les rangées de grille sont séquentiellement polarisées six fois par trame (une fois pour chacune des six sous-trames), elles ne sont désormais polarisées que trois fois par trame.On the other hand, the polarization of the cathode 11 again becomes similar to that of conventional screens. That is to say that during each "line time" which corresponds to the polarization of a grid row during the line scanning, all the cathode columns are brought to a potential which is a function of the brightness of the pixel at display along the current line in the color considered. Thus, in this second embodiment, the number of line scans is divided by two with respect to the first embodiment. The number of switches of the cathode 11 which are the most current consuming within the control electronics is therefore divided by two, compared with the first embodiment. Indeed, while in the first embodiment, all the grid rows are sequentially polarized six times per frame (once for each of the six sub-frames), they are now only polarized three times per frame.

On veillera cependant pour la mise en oeuvre de ce second mode de réalisation, à ce que les conducteurs 7 sur lesquels sont déposés les éléments luminophores 8 soient suffisants pour supporter le courant nécessaire à l'attraction simultanée des électrons le long de toute la bande d'éléments luminophores 8. En effet, alors que dans le premier mode de réalisation le courant global de ligne est réparti dans toutes les bandes dans la mesure où elles sont parallèles aux colonnes de la cathode, ce courant doit désormais pouvoir circuler dans un seul conducteur 7 car les bandes sont parallèles aux rangées de la grille.However, for the implementation of this second embodiment, care will be taken that the conductors 7 on which the phosphor elements 8 are deposited are sufficient to withstand the current necessary for the simultaneous attraction of the electrons along the entire band d phosphor elements 8. Indeed, while in the first embodiment the overall line current is distributed in all the bands insofar as they are parallel to the columns of the cathode, this current must now be able to flow in a single conductor 7 because the strips are parallel to the rows of the grid.

Pour ce faire, on pourra par exemple renforcer les conducteurs 7, classiquement réalisés par un dépôt d'ITO, par un dépôt conducteur de chaque côté des éléments luminophores 8.To do this, it is possible for example to reinforce the conductors 7, conventionally produced by an ITO deposition, by a conductive deposition on each side of the phosphor elements 8.

On pourra également utiliser le fait que la tension d'anode peut désormais être plus élevée, pour augmenter l'espace anode/cathode 6 et avoir recours à un mince film d'aluminium apposé sur les éléments luminophores 8. L'augmentation de l'énergie des électrons leur permet de traverser ce mince film d'aluminium.We can also use the fact that the anode voltage can now be higher, to increase the anode / cathode space 6 and have recourse to a thin aluminum film affixed to the phosphor elements 8. The increase in energy of the electrons allows them to pass through this thin film of aluminum.

Bien entendu, la présente invention est susceptible de diverses variantes et modifications qui apparaîtront à l'homme de l'art. En particulier, la réalisation pratique de l'électronique de commande conformément aux contraintes de fonctionnement qui ont été exposées en relation avec l'interconnexion des bandes d'éléments luminophores est à la portée de l'homme de l'art.Of course, the present invention is susceptible of various variants and modifications which will appear to those skilled in the art. In particular, the practical realization of the control electronics in accordance with the operating constraints which have been exposed in relation to the interconnection of the strips of phosphor elements is within the reach of those skilled in the art.

Claims (8)

Ecran plat de visualisation du type comportant une cathode (11) à micropointes (10) d'émission électronique organisée en colonnes (3), une grille (5) organisée en rangées (L) et une anode (12) pourvue d'éléments luminophores (8) organisés en groupes (13, 14) de bandes juxtaposées et électriquement isolées entre elles, l'intersection d'une rangée de grille et d'une colonne de cathode définissant un pixel de l'écran, caractérisé en ce que les groupes (13, 14) de bandes (8) de l'anode (12) sont électriquement connectés en deux réseaux, un premier réseau comprenant les groupes (13) de bandes de rang impair (R1, V1, B1 ; I), tandis qu'un second réseau comprend les groupes (14) de bandes de rang pair (R2, V2, B2 ; P) ; et en ce qu'il comporte une électronique de commande propre à adresser séquentiellement les groupes de rang impair, respectivement pair.Flat display screen of the type comprising a cathode (11) with microtips (10) of electronic emission organized in columns (3), a grid (5) organized in rows (L) and an anode (12) provided with phosphor elements (8) organized into groups (13, 14) of bands juxtaposed and electrically isolated from each other, the intersection of a row of grids and a cathode column defining a pixel of the screen, characterized in that the groups (13, 14) of bands (8) of the anode (12) are electrically connected in two networks, a first network comprising the groups (13) of bands of odd rank (R1, V1, B1; I), while 'a second network comprises the groups (14) of even rank bands (R2, V2, B2; P); and in that it includes control electronics suitable for sequentially addressing groups of odd, respectively even rank. Ecran plat de visualisation selon la revendication 1, caractérisé en ce que les groupes (13, 14) de bandes d'élément luminophores (8) sont parallèles aux colonnes de cathode et présentent une largeur sensiblement identique à la largeur de ces colonnes (3).Flat display screen according to claim 1, characterized in that the groups (13, 14) of bands of phosphor elements (8) are parallel to the cathode columns and have a width substantially identical to the width of these columns (3) . Ecran plat de visualisation selon la revendication 2, caractérisé en ce que les colonnes de cathode sont adressées individuellement par l'électronique de commande en deux réseaux correspondant aux réseaux de connexion des groupes (13, 14) de bandes de l'anode (12).Flat display screen according to claim 2, characterized in that the cathode columns are individually addressed by the control electronics in two networks corresponding to the connection networks of the groups (13, 14) of bands of the anode (12) . Ecran plat de visualisation selon la revendication 3, caractérisé en ce que l'électronique de commande comporte un inverseur de l'adressage des réseaux de connexion des groupes (13, 14) de bandes d'éléments luminophores (8).Flat display screen according to claim 3, characterized in that the control electronics include an inverter for addressing the connection networks of the groups (13, 14) of bands of phosphor elements (8). Ecran plat de visualisation selon la revendication 1, caractérisé en ce que les groupes (13, 14) de bandes d'éléments luminophores (8) sont parallèles aux rangées (L) de la grille (5) et présentent une largeur sensiblement identique à la largeur de ces rangées (L).Flat display screen according to claim 1, characterized in that the groups (13, 14) of bands of phosphor elements (8) are parallel to the rows (L) of the grid (5) and have a width substantially identical to the width of these rows (L). Ecran plat de visualisation selon la revendication 5, caractérisé en ce que l'électronique de commande comporte des moyens pour adresser séquentiellement les rangées (L) de grille de rang pair, respectivement impair, en même temps qu'elle adresse les groupes (13, 14) de bandes d'éléments luminophores (8) de rang pair, respectivement impair.Flat display screen according to claim 5, characterized in that the control electronics include means for sequentially addressing the rows (L) of grid of even, respectively odd rank, at the same time as it addresses the groups (13, 14) of bands of phosphor elements (8) of even, respectively odd rank. Ecran plat de visualisation selon l'une quelconque des revendications 1 à 6, caractérisé en ce que chacun desdits groupes (13, 14) est constitué d'une bande (I, P) d'éléments luminophores (8), les éléments luminophores de tous les groupes étant d'un même type.Flat display screen according to any one of claims 1 to 6, characterized in that each of said groups (13, 14) consists of a strip (I, P) of phosphor elements (8), the phosphor elements of all groups being of the same type. Ecran plat de visualisation selon l'une quelconque des revendications 1 à 6, caractérisé en ce que chacun desdits groupes (13, 14) est constitué de trois bandes (R, V, B) d'éléments luminophores (8) de couleurs différentes, chaque réseau comportant trois ensembles (R1, V1, B1 ; R2, V2, B2) de bandes d'éléments luminophores (8) électriquement connectées entre elles, et l'électronique de commande comportant des moyens pour adresser individuellement chaque ensemble d'un même réseau.Flat display screen according to any one of claims 1 to 6, characterized in that each of said groups (13, 14) consists of three strips (R, G, B) of phosphor elements (8) of different colors, each network comprising three sets (R1, V1, B1; R2, V2, B2) of strips of phosphor elements (8) electrically connected together, and the control electronics comprising means for individually addressing each set of the same network.
EP94410089A 1993-10-14 1994-10-13 Flat cold cathode display with switched anode Expired - Lifetime EP0649162B1 (en)

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FR9312530A FR2711273B1 (en) 1993-10-14 1993-10-14 Flat screen with double switched anode, using colored bands in the direction of the lines.

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EP0349425A1 (en) * 1988-06-29 1990-01-03 Commissariat A L'energie Atomique Three-colour fluorescent screen using micro-tip cathodes

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FR2711273B1 (en) 1996-01-19
EP0649162B1 (en) 1997-07-30
US5654729A (en) 1997-08-05
JPH07191628A (en) 1995-07-28
DE69404599T2 (en) 1997-12-04
DE69404599D1 (en) 1997-09-04
FR2711273A1 (en) 1995-04-21

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