EP0806790A1 - Dual gate microtip colour display - Google Patents

Dual gate microtip colour display Download PDF

Info

Publication number
EP0806790A1
EP0806790A1 EP97410051A EP97410051A EP0806790A1 EP 0806790 A1 EP0806790 A1 EP 0806790A1 EP 97410051 A EP97410051 A EP 97410051A EP 97410051 A EP97410051 A EP 97410051A EP 0806790 A1 EP0806790 A1 EP 0806790A1
Authority
EP
European Patent Office
Prior art keywords
grid
slots
potential
cathode
strips
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.)
Granted
Application number
EP97410051A
Other languages
German (de)
French (fr)
Other versions
EP0806790B1 (en
Inventor
Jean-Luc Grand-Clement
Bernard Bancal
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pixtech SA
Original Assignee
Pixtech SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Pixtech SA filed Critical Pixtech SA
Publication of EP0806790A1 publication Critical patent/EP0806790A1/en
Application granted granted Critical
Publication of EP0806790B1 publication Critical patent/EP0806790B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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 microtip display flat screens.
  • the cathode is made up of a very large number of microtips connected in columns, each of which can be addressed individually.
  • the ends of these microtips open into openings in an insulated grid.
  • This grid is divided into rows orthogonal to the columns, individually addressable.
  • An anode is located opposite the cathode / grid assembly and is separated from it by an empty space.
  • a group of three red, green and blue bands is approximately the width of a cathode column. All the bands of phosphors of the same color are interconnected so that it is possible to selectively address all the red bands, all the green bands or all the blue bands.
  • a complete image addressing cycle (a frame) comprises the step of addressing all the anode bands of the same kind, for example all the red bands and, while these red bands are at high voltage, to address each of the grid gnaws sequentially. During each polarization of a row of grid, all the cathode columns are addressed to potentials chosen to obtain a desired luminescence of each of the red pixels. The operation is then repeated for the green bands and the blue bands and one thus obtains a line by line and color by color addressing (sub-frame by sub-frame) of a complete frame.
  • This addressing mode requires switching of the potentials on the anodes.
  • the anode potential is generally a high potential for the energy of the electrons sent by the cathodes to cause sufficient illumination of the phosphors.
  • anode potentials of the order of 150 volts are indicated.
  • conventionally potentials of the order of 600 to 1000 volts are used and we would like to be able to use even higher potentials.
  • the need to switch the high anode potentials is a drawback.
  • An object of the present invention is to provide a new flat color microtip screen structure and a new method of addressing this screen such that it avoids switching high potentials.
  • the present invention provides a color microtip flat screen comprising a microtip cathode divided into independently addressable columns; a first pixel selection grid divided into independently addressable rows; a second color selection grid comprising a plurality of groups of slots extending in the direction of the columns, each group of three slots, corresponding to a column of the cathode, slots of the same rank from each group being connected to the same terminal; and an anode comprising groups of three parallel strips in a column of luminescent material of three chosen colors, a group of three strips corresponding to a column of the cathode, each strip corresponding to one of said slots, all the strips of luminescent material being brought into operation at the same potential.
  • the second grid is formed by cutting a thin metal sheet to form said slots and stiffening spacers, one strip out of three being delimited by the facing edges of said cut metal sheet , the other two strips out of three being formed by the facing edges of conductive layers deposited on an insulating layer itself formed on said sheet.
  • the above screen control method comprises the steps of bringing the anodes to a high anode potential, bringing the metallizations of the slots of the second grid corresponding to a first color to a validation potential and the other metallizations corresponding to the other two colors at a blocking potential, sequentially bring all the rows of the first grid to an addressing potential, when addressing each row of the first grid, polarize the cathode columns to a potential chosen for obtain a desired luminescence of the pixels of the selected color of said row, repeat the operation for the other two colors, and repeat all of the operations for the following frames.
  • An advantage of the present invention is that it leads to switching only the potentials of a cathode, of a first grid and of a second grid, which are all potentials of small values compared to that of the anode. As a result, the switching times can be shorter and the switching components simpler.
  • the cathode and lower grid assembly of a screen according to the present invention is identical to conventional embodiments such as that described in the aforementioned US patent.
  • This assembly is produced on an insulating substrate 1, for example a glass plate.
  • Microtips 2 are formed on columns of cathode conductors K1, K2, K3 ... Rows of gate conductors L1, L2, L3 ... are formed on an insulating layer covering the cathode conductors.
  • the ends of the microtips opening out substantially at the level of the upper parts of the grid openings.
  • this representation is very schematic and many known variants can be used, in particular, means for forming a resistor between each microtip and the associated cathode conductor.
  • the anode is similar to conventional anodes. Opposite each cathode column K, three strips of luminescent material R, G, B are arranged, also extending along columns. A difference compared to the state of the art is that these various bands, instead of being interconnected by bands of the same nature (the red bands, the green bands, the blue bands) are all brought to the same anode potential. during screen operation. For this, all the phosphor strips can for example be formed on the same layer conductive 6 formed on a substrate 7. In general, the layer 6 and the substrate 7 will be made of transparent materials, for example respectively a conductive layer of indium tin oxide (ITO) and a glass plate.
  • ITO indium tin oxide
  • the screen according to the present invention comprises a second grid provided with slots extending in the direction of the columns whose width dimensions correspond substantially to those of the strips of anode phosphors and respectively designated by the references A1R, A1G, A1B; A2R, A2G, A2B; A3R, A3G, A3B ...
  • each slot corresponds to a band of phosphor and we will speak below, for the sake of simplicity of "red slot”, “green slot”, “blue slot”.
  • this second grid was formed of an insulating material and that the internal edges of each of the slots were coated with a lateral metallization M1R, M1G, M1B; M2R, M2G, M2B; M3R, M3G, M3B ...
  • the lateral metallizations corresponding to slots associated with the same color are connected to the same terminal (not shown), that is to say that the metallizations M1R, M2R, M3R ... are connected to the same terminal as well as the metallizations M1G, M2G, M3G ... and M1B, M2B, M3B ...
  • spacers 9 have also been shown for the second grid. These spacers, which serve to ensure the mechanical strength of the grid, have no functional role and are not necessarily arranged in the regular manner shown.
  • isolation and spacing means are provided between the second grid and the upper face of the first grid, and between the second grid and the lower face of the anode. Many embodiments can be imagined by those skilled in the art for the production of these isolation means and these spacers.
  • the addressing mode of this device will be substantially the same as that described in the aforementioned American patent. except that, instead of switching the strips of anode phosphors, the lateral metallizations of the slots of the second grid are switched.
  • the advantage of the present invention emerges from an analysis of typical values of the potentials to be applied to the various electrodes of the screen.
  • red pixels corresponding to row L2 of the first grid This row L2 will be placed at a potential of the order of 80 volts, the other rows L1, L3 ... being grounded.
  • the columns K1, K2, K3 ... will be at potentials of the order of 0 to 30 volts depending on the desired brightness of the pixels considered.
  • the metallizations MR (M1R, M2R, M3R %) of the red slits of the second grid will be placed at a potential of +10 V compared to the mass to let pass the electrons emitted by the subjacent points towards the red phosphors .
  • the MG and MB metallizations of the green and blue slits will be placed at a potential of -10 V relative to the mass to block the electrons which would normally be directed through them towards the green and blue phosphors.
  • this second grid has not only a shutter function but also a focusing function. We are therefore assured that, when the "red slots" of the second grid are validated, only red phosphors will be bombarded. This focusing effect will be optimized by adjusting the color selection potential applied to the slots of the second grid.
  • Another advantage of the present invention is that, since there is no longer any need to switch the anode, it can be placed at a very high potential, for example several thousand of volts so that the energy of the electrons will be much higher and will produce better illumination of the phosphors.
  • these phosphors can then be coated on the side of their internal face with a thin conductive layer, for example a thin layer of aluminum which, in known manner, provides numerous advantages, in particular for avoiding parasitic lighting phenomena. .
  • an additional advantage of the present invention is that it makes it possible to use cathode and first grid systems identical to those already manufactured in the prior art and therefore requires only one modification (a simplification) of the anode structure and the realization of an additional grid.
  • isolation structures and spacers to be placed between the additional grid and the plates.
  • anode on the one hand and cathode / grid on the other.
  • These isolation and spacing systems may consist of spacing balls or perforated spacing plates.
  • FIG. 2 represents an exemplary embodiment according to the present invention of a second grid.
  • This grid is formed from a metal sheet 10 stamped to define the slots AR, AG, AB (only portions of the slots A2R, A2G, A2B, A3R, A3G are shown) and stiffening spacers 9.
  • the slots AG are directly delimited by facing edges of the metal sheet 10.
  • the slots AR and AB are defined by the facing edges of conductive layers 11 formed on an insulating layer 12 deposited on the metal sheet. The deposition and delimitation of these insulating and conductive layers can be carried out in a conventional manner. It is clear that all the metallizations of the AG slots have the same potential (that of the metal foil). Similarly, the metallizations of each of the slots AB and the metallizations of each of the slots AR will be brought to the same potential.
  • one of the three electrodes of the second grid is made of the material of a metal sheet makes it particularly simple to interconnect the two other groups of metallizations of this grid which could, for example, be connected by metallized and insulated strips arranged at opposite ends of the metallizations of the slots.
  • Another advantage of producing the second grid from a stamped conductive plate is that such a conductive plate can be very thin while having good mechanical strength. Its thickness may for example be of the order of 1 to 5 tenths of a millimeter and the metal which constitutes it will be for example aluminum, copper, stainless steel, nickel, an aluminum alloy.
  • a grid according to the present invention could be used with a screen whose diagonal dimension is of the order of a meter, the dimensions of a pixel being of the order of a millimeter.
  • the grid pitch will then be of the order of 0.15 mm, the distance between groups of three slots being of the order of 0.25 mm.

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

The screen has a cathode (2) formed of microdots arranged in columns (K1-K3) under an insulating coating which carries the pixel selection grid divided into rows (L1-L3). The colour selection grid has groups of slits (e.g. A1R,A1G,A1B) extending in the direction of the columns, each group covering the width of one column. Slits of the same rank in each group are connected to a common terminal. The anode is similarly divided into groups of parallel strips of luminophors of the primary colours, each strip corresponding to one slit, and all strips being returned to the same voltage.

Description

La présente invention concerne des écrans plats d'affichage à micropointes.The present invention relates to microtip display flat screens.

Un exemple d'un tel écran et de son mode d'adressage est décrit dans le brevet des Etats-Unis d'Amérique 5 225 820 au nom de Jean-Frédéric Clerc.An example of such a screen and of its addressing mode is described in US Patent 5,225,820 in the name of Jean-Frédéric Clerc.

Dans cet écran la cathode est constituée d'un très grand nombre de micropointes connectées selon des colonnes dont chacune peut être adressée individuellement. Les extrémités de ces micropointes débouchent dans des ouvertures d'une grille isolée. Cette grille est divisée en rangées orthogonales aux colonnes, adressables individuellement.In this screen, the cathode is made up of a very large number of microtips connected in columns, each of which can be addressed individually. The ends of these microtips open into openings in an insulated grid. This grid is divided into rows orthogonal to the columns, individually addressable.

Une anode est située en regard de l'ensemble cathode/ grille et en est séparée par un espace vide. Sur cette anode sont disposés des groupes de bandes d'éléments luminescents ou luminophores de trois couleurs distinctes, par exemple rouges, verts et bleus. Ces bandes sont disposées en colonnes parallèlement aux colonnes de cathode. Un groupe de trois bandes rouge, verte et bleue a sensiblement la largeur d'une colonne de cathode. Toutes les bandes de luminophores de même couleur sont interconnectées de sorte qu'il est possible d'adresser sélectivement toutes les bandes rouges, toutes les bandes vertes ou toutes les bandes bleues.An anode is located opposite the cathode / grid assembly and is separated from it by an empty space. On this anode are arranged groups of bands of luminescent or phosphor elements of three distinct colors, for example red, green and blue. These strips are arranged in columns parallel to the cathode columns. A group of three red, green and blue bands is approximately the width of a cathode column. All the bands of phosphors of the same color are interconnected so that it is possible to selectively address all the red bands, all the green bands or all the blue bands.

Un cycle d'adressage d'une image complète (une trame) comprend l'étape consistant à adresser toutes les bandes d'anode de même nature, par exemple toutes les bandes rouges et, pendant que ces bandes rouges sont à haute tension, à adresser séquentiellement chacune des rongées de grille. Lors de chaque polarisation d'une rangée de grille, toutes les colonnes de cathode sont adressées à des potentiels choisis pour obtenir une luminescence désirée de chacun des pixels rouges. L'opération est ensuite répétée pour les bandes vertes et les bandes bleues et l'on obtient ainsi un adressage ligne par ligne et couleur par couleur (sous-trame par sous-trame) d'une trame complète.A complete image addressing cycle (a frame) comprises the step of addressing all the anode bands of the same kind, for example all the red bands and, while these red bands are at high voltage, to address each of the grid gnaws sequentially. During each polarization of a row of grid, all the cathode columns are addressed to potentials chosen to obtain a desired luminescence of each of the red pixels. The operation is then repeated for the green bands and the blue bands and one thus obtains a line by line and color by color addressing (sub-frame by sub-frame) of a complete frame.

Ce mode d'adressage nécessite une commutation des potentiels sur les anodes. Or, le potentiel d'anode est généralement un potentiel élevé pour que l'énergie des électrons envoyés par les cathodes provoque un éclairement suffisant des luminophores. Dans le brevet américain susmentionné, il est indiqué des potentiels d'anode de l'ordre de 150 volts. En pratique, pour obtenir un éclairement suffisant avec des luminophores classiques, on utilise classiquement des potentiels de l'ordre de 600 à 1000 volts et l'on souhaiterait pouvoir utiliser des potentiels encore plus élevés. Or, il est d'autant plus difficile de réaliser une commutation de potentiel sur une électrode que ce potentiel est élevé. Ainsi, la nécessité de commuter les potentiels élevés d'anode constitue un inconvénient.This addressing mode requires switching of the potentials on the anodes. However, the anode potential is generally a high potential for the energy of the electrons sent by the cathodes to cause sufficient illumination of the phosphors. In the aforementioned US patent, anode potentials of the order of 150 volts are indicated. In practice, to obtain sufficient illumination with conventional phosphors, conventionally potentials of the order of 600 to 1000 volts are used and we would like to be able to use even higher potentials. However, it is all the more difficult to carry out a potential switching on an electrode that this potential is high. Thus, the need to switch the high anode potentials is a drawback.

Un objet de la présente invention est de proposer une nouvelle structure d'écran plat couleur à micropointes et un nouveau mode d'adressage de cet écran tels que l'on évite de commuter des potentiels élevés.An object of the present invention is to provide a new flat color microtip screen structure and a new method of addressing this screen such that it avoids switching high potentials.

Pour atteindre cet objet, la présente invention prévoit un écran plat couleur à micropointes comprenant une cathode à micropointes divisée en colonnes adressables indépendamment ; une première grille de sélection de pixels divisée en rangées adressables indépendamment ; une deuxième grille de sélection de couleur comprenant une pluralité de groupes de fentes s'étendant selon la direction des colonnes, chaque groupe de trois fentes, correspondant à une colonne de la cathode, des fentes de même rang de chaque groupe étant connectées à une même borne ; et une anode comprenant des groupes de trois bandes parallèles en colonne de matériau luminescent de trois couleurs choisies, un groupe de trois bandes correspondant à une colonne de la cathode, chaque bande correspondant à l'une desdites fentes, toutes les bandes de matériau luminescent étant portées en fonctionnement à un même potentiel.To achieve this object, the present invention provides a color microtip flat screen comprising a microtip cathode divided into independently addressable columns; a first pixel selection grid divided into independently addressable rows; a second color selection grid comprising a plurality of groups of slots extending in the direction of the columns, each group of three slots, corresponding to a column of the cathode, slots of the same rank from each group being connected to the same terminal; and an anode comprising groups of three parallel strips in a column of luminescent material of three chosen colors, a group of three strips corresponding to a column of the cathode, each strip corresponding to one of said slots, all the strips of luminescent material being brought into operation at the same potential.

Selon un mode de réalisation de la présente invention, la deuxième grille est formée par découpe d'une feuille métallique mince pour y former lesdites fentes et des entretoises de rigidification, une bande sur trois étant délimitée par les bords en regard de ladite feuille métallique découpée, les deux autres bandes sur trois étant formées par les bords en regard de couches conductrices déposées sur une couche isolante elle-même formée sur ladite feuille.According to one embodiment of the present invention, the second grid is formed by cutting a thin metal sheet to form said slots and stiffening spacers, one strip out of three being delimited by the facing edges of said cut metal sheet , the other two strips out of three being formed by the facing edges of conductive layers deposited on an insulating layer itself formed on said sheet.

Le procédé de commande de l'écran ci-dessus comprend les étapes consistant à porter les anodes à un potentiel élevé d'anode, porter les métallisations des fentes de la deuxième grille correspondant à une première couleur à un potentiel de validation et les autres métallisations correspondant aux deux autres couleurs à un potentiel de blocage, porter séquentiellement toutes les rangées de la première grille à un potentiel d'adressage, lors de l'adressage de chaque rangée de la première grille, polariser les colonnes de cathode à un potentiel choisi pour obtenir une luminescence désirée des pixels de la couleur sélectionnée de ladite rangée, répéter l'opération pour les deux autres couleurs, et répéter l'ensemble des opérations pour les trames suivantes.The above screen control method comprises the steps of bringing the anodes to a high anode potential, bringing the metallizations of the slots of the second grid corresponding to a first color to a validation potential and the other metallizations corresponding to the other two colors at a blocking potential, sequentially bring all the rows of the first grid to an addressing potential, when addressing each row of the first grid, polarize the cathode columns to a potential chosen for obtain a desired luminescence of the pixels of the selected color of said row, repeat the operation for the other two colors, and repeat all of the operations for the following frames.

Un avantage de la présente invention est qu'elle conduit à commuter uniquement les potentiels d'une cathode, d'une première grille et d'une deuxième grille, qui sont tous des potentiels de faibles valeurs devant celui de l'anode. Il en résulte que les durées de commutation peuvent être plus courtes et les composants de commutation plus simples.An advantage of the present invention is that it leads to switching only the potentials of a cathode, of a first grid and of a second grid, which are all potentials of small values compared to that of the anode. As a result, the switching times can be shorter and the switching components simpler.

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

  • la figure 1 est une vue en perspective explosée et schématique d'une portion d'un écran plat à micropointes selon un mode de réalisation de la présente invention ; et
  • la figure 2 est une vue en perspective partielle et simplifiée d'une deuxième grille 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 an embodiment of the present invention given without limitation in relation to the attached figures among which:
  • Figure 1 is an exploded and schematic perspective view of a portion of a microtip flat screen according to an embodiment of the present invention; and
  • Figure 2 is a partial and simplified perspective view of a second grid according to an embodiment of the present invention.

Comme le représente la figure 1, l'ensemble de cathode et de grille inférieure d'un écran selon la présente invention est identique aux réalisations classiques telles que celle décrite dans le brevet américain susmentionné. Cet ensemble est réalisé sur un substrat isolant 1, par exemple une plaque de verre. Des micropointes 2 sont formées sur des colonnes de conducteurs de cathode K1, K2, K3... Des rangées de conducteurs de grille L1, L2, L3... sont formées sur une couche isolante recouvrant les conducteurs de cathode. Les extrémités des micropointes débouchant sensiblement au niveau des parties supérieures d'ouvertures de la grille. Bien entendu, cette représentation est très schématique et de nombreuses variantes de réalisation connues pourront être utilisées, notamment, des moyens pour former une résistance entre chaque micropointe et le conducteur de cathode associé.As shown in Figure 1, the cathode and lower grid assembly of a screen according to the present invention is identical to conventional embodiments such as that described in the aforementioned US patent. This assembly is produced on an insulating substrate 1, for example a glass plate. Microtips 2 are formed on columns of cathode conductors K1, K2, K3 ... Rows of gate conductors L1, L2, L3 ... are formed on an insulating layer covering the cathode conductors. The ends of the microtips opening out substantially at the level of the upper parts of the grid openings. Of course, this representation is very schematic and many known variants can be used, in particular, means for forming a resistor between each microtip and the associated cathode conductor.

L'anode est similaire aux anodes classiques. En regard de chaque colonne de cathode K, sont disposées trois bandes de matériau luminescent R, G, B s'étendant également selon des colonnes. Une différence par rapport à l'état de la technique est que ces diverses bandes, au lieu d'être interconnectées par bandes de même nature (les bandes rouges, les bandes vertes, les bandes bleues) sont toutes portées au même potentiel d'anode lors du fonctionnement de l'écran. Pour ceci, toutes les bandes de luminophores peuvent par exemple être formées sur une même couche conductrice 6 formée sur un substrat 7. De façon générale, la couche 6 et le substrat 7 seront en des matériaux transparents, par exemple respectivement une couche conductrice d'oxyde d'indium et d'étain (ITO) et une plaque de verre.The anode is similar to conventional anodes. Opposite each cathode column K, three strips of luminescent material R, G, B are arranged, also extending along columns. A difference compared to the state of the art is that these various bands, instead of being interconnected by bands of the same nature (the red bands, the green bands, the blue bands) are all brought to the same anode potential. during screen operation. For this, all the phosphor strips can for example be formed on the same layer conductive 6 formed on a substrate 7. In general, the layer 6 and the substrate 7 will be made of transparent materials, for example respectively a conductive layer of indium tin oxide (ITO) and a glass plate.

L'écran selon la présente invention comprend une deuxième grille munie de fentes s'étendant dans le sens des colonnes dont les dimensions en largeur correspondent sensiblement à celles des bandes de luminophores d'anode et respectivement désignées par les références A1R, A1G, A1B ; A2R, A2G, A2B ; A3R, A3G, A3B... Ainsi, chaque fente correspond à une bande de luminophore et l'on parlera ci-après, par souci de simplicité de "fente rouge", "fente verte", "fente bleue". Dans le mode de réalisation simplifié et schématique de la figure 1, on a supposé que cette deuxième grille était formée d'un matériau isolant et que les bords internes de chacune des fentes étaient revêtus d'une métallisation latérale M1R, M1G, M1B ; M2R, M2G, M2B ; M3R, M3G, M3B... Les métallisations latérales correspondant à des fentes associées à une même couleur sont reliées à une même borne (non représentée), c'est-à-dire que les métallisations M1R, M2R, M3R... sont connectées à une même borne de même que les métallisations M1G, M2G, M3G... et M1B, M2B, M3B...The screen according to the present invention comprises a second grid provided with slots extending in the direction of the columns whose width dimensions correspond substantially to those of the strips of anode phosphors and respectively designated by the references A1R, A1G, A1B; A2R, A2G, A2B; A3R, A3G, A3B ... Thus, each slot corresponds to a band of phosphor and we will speak below, for the sake of simplicity of "red slot", "green slot", "blue slot". In the simplified and schematic embodiment of FIG. 1, it has been assumed that this second grid was formed of an insulating material and that the internal edges of each of the slots were coated with a lateral metallization M1R, M1G, M1B; M2R, M2G, M2B; M3R, M3G, M3B ... The lateral metallizations corresponding to slots associated with the same color are connected to the same terminal (not shown), that is to say that the metallizations M1R, M2R, M3R ... are connected to the same terminal as well as the metallizations M1G, M2G, M3G ... and M1B, M2B, M3B ...

Dans la figure 1, on a aussi représenté pour la deuxième grille des entretoises 9. Ces entretoises, qui servent à assurer la tenue mécanique de la grille, n'ont pas de rôle fonctionnel et ne sont pas nécessairement disposées de la façon régulière représentée.In FIG. 1, spacers 9 have also been shown for the second grid. These spacers, which serve to ensure the mechanical strength of the grid, have no functional role and are not necessarily arranged in the regular manner shown.

Bien que cela ne soit pas représenté dans la figure, des moyens d'isolement et d'espacement sont prévus entre la deuxième grille et la face supérieure de la première grille, et entre la deuxième grille et la face inférieure de l'anode. De nombreux modes de réalisation pourront être imaginés par l'homme de l'art pour la réalisation de ces moyens d'isolement et de ces espaceurs.Although this is not shown in the figure, isolation and spacing means are provided between the second grid and the upper face of the first grid, and between the second grid and the lower face of the anode. Many embodiments can be imagined by those skilled in the art for the production of these isolation means and these spacers.

Le mode d'adressage de ce dispositif sera sensiblement le même que celui décrit dans le brevet américain susmentionné sauf que, au lieu de réaliser une commutation des bandes de luminophores d'anode, on réalise une commutation des métallisations latérales des fentes de la deuxième grille.The addressing mode of this device will be substantially the same as that described in the aforementioned American patent. except that, instead of switching the strips of anode phosphors, the lateral metallizations of the slots of the second grid are switched.

L'avantage de la présente invention ressort d'une analyse de valeurs typiques des potentiels à appliquer aux diverses électrodes de l'écran.The advantage of the present invention emerges from an analysis of typical values of the potentials to be applied to the various electrodes of the screen.

Supposons que l'on veuille adresser les pixels rouges correspondant à la rangée L2 de la première grille. Cette rangée L2 sera placée à un potentiel de l'ordre de 80 volts, les autres rangées L1, L3... étant à la masse. Les colonnes K1, K2, K3... seront à des potentiels de l'ordre de 0 à 30 volts selon la luminosité désirée des pixels considérés. Les métallisations MR (M1R, M2R, M3R...) des fentes rouges de la deuxième grille seront placées à un potentiel de +10 V par rapport à la masse pour laisser passer les électrons émis par les pointes sous-jacentes vers les luminophores rouges. Les métallisations MG et MB des fentes vertes et bleues seront placées à un potentiel de -10 V par rapport à la masse pour bloquer les électrons qui seraient normalement dirigés à travers elles vers les luminophores verts et bleus. On notera que cette deuxième grille a non seulement une fonction d'obturateur mais aussi une fonction de focalisation. On est donc assuré que, quand les "fentes rouges" de la deuxième grille sont validées, seuls des luminophores rouges seront bombardés. Cet effet de focalisation sera optimisé par un réglage du potentiel de sélection de couleur appliqué aux fentes de la deuxième grille.Suppose we want to address the red pixels corresponding to row L2 of the first grid. This row L2 will be placed at a potential of the order of 80 volts, the other rows L1, L3 ... being grounded. The columns K1, K2, K3 ... will be at potentials of the order of 0 to 30 volts depending on the desired brightness of the pixels considered. The metallizations MR (M1R, M2R, M3R ...) of the red slits of the second grid will be placed at a potential of +10 V compared to the mass to let pass the electrons emitted by the subjacent points towards the red phosphors . The MG and MB metallizations of the green and blue slits will be placed at a potential of -10 V relative to the mass to block the electrons which would normally be directed through them towards the green and blue phosphors. It will be noted that this second grid has not only a shutter function but also a focusing function. We are therefore assured that, when the "red slots" of the second grid are validated, only red phosphors will be bombarded. This focusing effect will be optimized by adjusting the color selection potential applied to the slots of the second grid.

Pour passer d'une couleur à une autre, il suffit donc de commuter les potentiels appliqués à la deuxième grille entre deux valeurs de potentiel relativement voisines (+ et -10 V) par rapport au potentiel de la grille. Il suffit pour cela de composants de commutation relativement simples et à faible coût et en outre la vitesse de commutation peut être élevée.To go from one color to another, it suffices to switch the potentials applied to the second grid between two relatively close potential values (+ and -10 V) with respect to the potential of the grid. Relatively simple and low-cost switching components are sufficient for this, and in addition the switching speed can be high.

Un autre avantage de la présente invention est que, puisqu'il n'y a plus à commuter l'anode, celle-ci pourra être placée à un potentiel très élevé, par exemple plusieurs milliers de volts de sorte que l'énergie des électrons sera beaucoup plus élevée et produira un meilleur éclairement des luminophores. En outre, ces luminophores pourront alors être revêtus du côté de leur face interne d'une couche mince conductrice, par exemple une couche mince d'aluminium qui, de façon connue, procure de nombreux avantages, notamment pour éviter des phénomènes d'éclairement parasites.Another advantage of the present invention is that, since there is no longer any need to switch the anode, it can be placed at a very high potential, for example several thousand of volts so that the energy of the electrons will be much higher and will produce better illumination of the phosphors. In addition, these phosphors can then be coated on the side of their internal face with a thin conductive layer, for example a thin layer of aluminum which, in known manner, provides numerous advantages, in particular for avoiding parasitic lighting phenomena. .

Les diverses valeurs numériques ci-dessus ont été indiquées uniquement à titre d'exemple et l'homme de l'art saura adapter les valeurs indiquées en fonction du dispositif particulier utilisé et de l'effet recherché.The various numerical values above have been given only by way of example and a person skilled in the art will be able to adapt the values indicated according to the particular device used and the desired effect.

Outre les avantages déjà énoncés, on notera qu'un avantage supplémentaire de la présente invention est qu'elle permet d'utiliser des systèmes de cathode et de première grille identiques à ceux déjà fabriqués dans l'art antérieur et ne nécessite donc qu'une modification (une simplification) de la structure d'anode et la réalisation d'une grille supplémentaire.In addition to the advantages already stated, it will be noted that an additional advantage of the present invention is that it makes it possible to use cathode and first grid systems identical to those already manufactured in the prior art and therefore requires only one modification (a simplification) of the anode structure and the realization of an additional grid.

Bien entendu, la présente invention est susceptible de nombreuses variantes et modifications qui apparaîtront à l'homme de l'art notamment en ce qui concerne la réalisation des structures d'isolement et d'espaceurs à disposer entre la grille supplémentaire et les plaques d'anode d'une part et de cathode/grille d'autre part. Ces systèmes d'isolement et d'espacement pourront être constitués de billes d'espacement ou de plaques perforées d'espacement. Notamment, on utilisera de préférence une plaque isolante perforée d'espacement entre la deuxième grille et l'anode.Of course, the present invention is susceptible of numerous variants and modifications which will appear to those skilled in the art, in particular as regards the production of isolation structures and spacers to be placed between the additional grid and the plates. anode on the one hand and cathode / grid on the other. These isolation and spacing systems may consist of spacing balls or perforated spacing plates. In particular, it is preferable to use an insulating plate perforated with spacing between the second grid and the anode.

La figure 2 représente un exemple de réalisation selon la présente invention d'une deuxième grille. Cette grille est constituée à partir d'une feuille métallique 10 estampée pour définir les fentes AR, AG, AB (seules des portions des fentes A2R, A2G, A2B, A3R, A3G sont représentées) et des entretoises de rigidification 9.FIG. 2 represents an exemplary embodiment according to the present invention of a second grid. This grid is formed from a metal sheet 10 stamped to define the slots AR, AG, AB (only portions of the slots A2R, A2G, A2B, A3R, A3G are shown) and stiffening spacers 9.

Dans le mode de réalisation représenté, les fentes AG (A2G, A3G) sont directement délimitées par des bords en regard de la feuille métallique 10. Par contre, les fentes AR et AB sont définies par les bords en regard de couches conductrices 11 formées sur une couche isolante 12 déposée sur la feuille métallique. Le dépôt et la délimitation de ces couches isolantes et conductrices pourront être réalisées de façon classique. Il est clair que toutes les métallisations des fentes AG sont au même potentiel (celui de la feuille métallique). De même, les métallisations de chacune des fentes AB et les métallisations de chacune des fentes AR seront portées à un même potentiel.In the embodiment shown, the slots AG (A2G, A3G) are directly delimited by facing edges of the metal sheet 10. On the other hand, the slots AR and AB are defined by the facing edges of conductive layers 11 formed on an insulating layer 12 deposited on the metal sheet. The deposition and delimitation of these insulating and conductive layers can be carried out in a conventional manner. It is clear that all the metallizations of the AG slots have the same potential (that of the metal foil). Similarly, the metallizations of each of the slots AB and the metallizations of each of the slots AR will be brought to the same potential.

Le fait que l'une des trois électrodes de la deuxième grille est constituée par le matériau d'une feuille métallique rend particulièrement simple l'interconnexion des deux autres groupes de métallisations de cette grille qui pourront par exemple être reliés par des bandes métallisées et isolées disposées aux extrémités opposées des métallisations des fentes.The fact that one of the three electrodes of the second grid is made of the material of a metal sheet makes it particularly simple to interconnect the two other groups of metallizations of this grid which could, for example, be connected by metallized and insulated strips arranged at opposite ends of the metallizations of the slots.

Un autre avantage de la réalisation de la deuxième grille à partir d'une plaque conductrice estampée est qu'une telle plaque conductrice peut être très mince tout en ayant une bonne tenue mécanique. Son épaisseur peut par exemple être de l'ordre de 1 à 5 dixièmes de millimètres et le métal qui la constitue sera par exemple de l'aluminium, du cuivre, de l'Inox, du nickel, un alliage d'aluminium.Another advantage of producing the second grid from a stamped conductive plate is that such a conductive plate can be very thin while having good mechanical strength. Its thickness may for example be of the order of 1 to 5 tenths of a millimeter and the metal which constitutes it will be for example aluminum, copper, stainless steel, nickel, an aluminum alloy.

A titre d'exemple de valeurs numériques, une grille selon la présente invention pourra être utilisée avec un écran dont la dimension diagonale est de l'ordre du mètre, les dimensions d'un pixel étant de l'ordre du millimètre. Le pas de la grille sera alors de l'ordre de 0,15 mm, la distance entre groupes de trois fentes étant de l'ordre de 0,25 mm.As an example of numerical values, a grid according to the present invention could be used with a screen whose diagonal dimension is of the order of a meter, the dimensions of a pixel being of the order of a millimeter. The grid pitch will then be of the order of 0.15 mm, the distance between groups of three slots being of the order of 0.25 mm.

Claims (3)

Ecran plat couleur à micropointes comprenant une cathode à micropointes (2) divisée en colonnes (K1, K2, K3...) adressables indépendamnent ; une première grille de sélection de pixels divisée en rangées (L1, L2, L3...) adressables indépendamment ; une deuxième grille de sélection de couleur comprenant une pluralité de groupes de fentes s'étendant selon la direction des colonnes, chaque groupe de trois fentes (AIR, AiG, AiB), correspondant à une colonne de la cathode, des fentes de même rang de chaque groupe étant connectées à une même borne ; et une anode comprenant des groupes de trois bandes parallèles en colonne de matériau luminescent de trois couleurs choisies (RGB), un groupe de trois bandes correspondant à une colonne de la cathode, chaque bande correspondant à l'une desdites fentes, toutes les bandes de matériau luminescent étant portées en fonctionnement à un même potentiel. Color microtip flat screen comprising a microtip cathode (2) divided into columns (K1, K2, K3 ...) independently addressable; a first pixel selection grid divided into rows (L1, L2, L3 ...) independently addressable; a second color selection grid comprising a plurality of groups of slots extending in the direction of the columns, each group of three slots (AIR, AiG, AiB), corresponding to a column of the cathode, slots of the same rank each group being connected to the same terminal; and an anode comprising groups of three parallel strips in a column of luminescent material of three chosen colors (RGB), a group of three strips corresponding to a column of the cathode, each strip corresponding to one of said slots, all the strips of material luminescent being brought into operation at the same potential. Ecran selon la revendication 1, caractérisée en ce que la deuxième grille est formée par découpe d'une feuille métallique mince (10) pour y former lesdites fentes et des entretoises de rigidification (9), une bande sur trois étant délimitée par les bords en regard de ladite feuille métallique découpée, les deux autres bandes sur trois étant formées par les bords en regard de couches conductrices déposées sur une couche isolante elle-même formée sur ladite feuille.Screen according to claim 1, characterized in that the second grid is formed by cutting a thin metal sheet (10) to form said slots and stiffening spacers (9), one strip out of three being delimited by the edges in look of said cut metal sheet, the other two strips out of three being formed by the edges facing conductive layers deposited on an insulating layer itself formed on said sheet. Procédé de commande d'un écran selon la revendication 1, caractérisé en ce qu'il comprend les étapes suivantes : porter les anodes à un potentiel élevé d'anode, porter les métallisations des fentes de la deuxième grille correspondant à une première couleur à un potentiel de validation et les autres métallisations correspondant aux deux autres couleurs à un potentiel de blocage, porter séquentiellement toutes les rangées de la première grille à un potentiel d'adressage, lors de l'adressage de chaque rangée de la première grille, polariser les colonnes de cathode à un potentiel choisi pour obtenir une luminescence désirée des pixels de la couleur sélectionnée de ladite rangée, répéter l'opération pour les deux autres couleurs, et répéter l'ensemble des opérations pour les trames suivantes. Method for controlling a screen according to claim 1, characterized in that it comprises the following steps: bring the anodes to a high anode potential, bringing the metallizations of the slots of the second grid corresponding to a first color to a validation potential and the other metallizations corresponding to the other two colors to a blocking potential, sequentially bringing all the rows of the first grid to an addressing potential, during the addressing of each row of the first grid, polarizing the cathode columns at a chosen potential to obtain a desired luminescence of the pixels of the selected color of said row, repeat for the other two colors, and repeat all of the operations for the following frames.
EP97410051A 1996-05-06 1997-05-02 Dual gate microtip colour display Expired - Lifetime EP0806790B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9605934A FR2748348B1 (en) 1996-05-06 1996-05-06 COLOR SCREEN WITH MICROPOINT DOUBLE GRID
FR9605934 1996-05-06

Publications (2)

Publication Number Publication Date
EP0806790A1 true EP0806790A1 (en) 1997-11-12
EP0806790B1 EP0806790B1 (en) 2003-02-19

Family

ID=9492082

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97410051A Expired - Lifetime EP0806790B1 (en) 1996-05-06 1997-05-02 Dual gate microtip colour display

Country Status (5)

Country Link
US (1) US6034658A (en)
EP (1) EP0806790B1 (en)
JP (1) JPH1055771A (en)
DE (1) DE69719110T2 (en)
FR (1) FR2748348B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0854493A1 (en) * 1997-01-16 1998-07-22 International Business Machines Corporation Cathode for display device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100463190B1 (en) 2002-06-12 2004-12-23 삼성에스디아이 주식회사 Spacer structure with metal mesh and flat panel display device having the same

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63150837A (en) * 1986-12-16 1988-06-23 Canon Inc Electron emitting device
EP0404022A2 (en) * 1989-06-19 1990-12-27 Matsushita Electric Industrial Co., Ltd. Flat configuration image display apparatus and manufacturing method thereof
WO1993021650A1 (en) * 1992-04-10 1993-10-28 Silicon Video Corporation Self supporting flat video display
JPH06139918A (en) * 1992-10-23 1994-05-20 Shimadzu Corp Electron emission element
EP0660368A1 (en) * 1993-12-22 1995-06-28 Gec-Marconi Limited Electron field emission devices
WO1995020821A1 (en) * 1994-01-31 1995-08-03 Silicon Video Corporation Field emitter with focusing ridges

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69026353T2 (en) * 1989-12-19 1996-11-14 Matsushita Electric Ind Co Ltd Field emission device and method of manufacturing the same
US5150067A (en) * 1990-04-16 1992-09-22 Mcmillan Michael R Electromagnetic pulse generator using an electron beam produced with an electron multiplier
DE69323485T2 (en) * 1992-11-06 1999-07-22 Mitsubishi Electric Corp PICTURE PLAYER
US5650690A (en) * 1994-11-21 1997-07-22 Candescent Technologies, Inc. Backplate of field emission device with self aligned focus structure and spacer wall locators
FR2732159B1 (en) * 1995-03-22 1997-06-13 Pixtech Sa DOUBLE GRID DISPLAY FLAT SCREEN
US5760858A (en) * 1995-04-21 1998-06-02 Texas Instruments Incorporated Field emission device panel backlight for liquid crystal displays

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63150837A (en) * 1986-12-16 1988-06-23 Canon Inc Electron emitting device
EP0404022A2 (en) * 1989-06-19 1990-12-27 Matsushita Electric Industrial Co., Ltd. Flat configuration image display apparatus and manufacturing method thereof
WO1993021650A1 (en) * 1992-04-10 1993-10-28 Silicon Video Corporation Self supporting flat video display
JPH06139918A (en) * 1992-10-23 1994-05-20 Shimadzu Corp Electron emission element
EP0660368A1 (en) * 1993-12-22 1995-06-28 Gec-Marconi Limited Electron field emission devices
WO1995020821A1 (en) * 1994-01-31 1995-08-03 Silicon Video Corporation Field emitter with focusing ridges

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 012, no. 412 (E - 676) 31 October 1988 (1988-10-31) *
PATENT ABSTRACTS OF JAPAN vol. 018, no. 434 (E - 1592) 12 August 1994 (1994-08-12) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0854493A1 (en) * 1997-01-16 1998-07-22 International Business Machines Corporation Cathode for display device
US5889372A (en) * 1997-01-16 1999-03-30 International Business Machines Corporation Device cathode with extractor grid for display

Also Published As

Publication number Publication date
FR2748348A1 (en) 1997-11-07
JPH1055771A (en) 1998-02-24
DE69719110T2 (en) 2003-10-09
EP0806790B1 (en) 2003-02-19
DE69719110D1 (en) 2003-03-27
US6034658A (en) 2000-03-07
FR2748348B1 (en) 1998-07-24

Similar Documents

Publication Publication Date Title
FR2708380A1 (en) Image display device and associated control circuit
EP0704877A1 (en) Electric protection of an anode of a plat viewing screen
FR2682211A1 (en) Fluorescent, flat-type display device
EP0867912A1 (en) Mounting of spacers in a flat display
EP1139374A1 (en) Cathode plate of a flat viewing screen
FR2626732A1 (en) VISUALIZATION DEVICE IN COLOR-MONOCHROME
EP0806790B1 (en) Dual gate microtip colour display
FR2731555A1 (en) Field emission construction esp. for display having micro-point cold cathodes
EP0734042B1 (en) Anode of a flat viewing screen with resistive strips
FR2714209A1 (en) Display screen with field emission electron source
EP2153274B1 (en) Lighting device for liquid crystal screen
FR2731291A1 (en) Control circuit for field-emission colour image display
EP0649162B1 (en) Flat cold cathode display with switched anode
EP0734043B1 (en) Double-gated flat display screen
EP0802559B1 (en) Flat panel display with hydrogen source
EP0844642A1 (en) Flat panel display with focusing gates
EP1032017B1 (en) Resistive anode of a flat viewing screen
EP0877407A1 (en) Anode of a flat display screen
EP0844643A1 (en) Flat panel display with lateral deviation
FR2770338A1 (en) ELIMINATION OF THE EFFECT OF MOIRE FROM A FLAT VISUALIZATION SCREEN
WO2000075952A1 (en) Matrix-type plasma panel
EP0867908A1 (en) Uniforming the potential electron emission 0f a cathode of a flat screen with microtips
EP1073088A1 (en) Fabrication of an anode of a flat viewing screen,anode obtained by said method and flat screen using such anode
EP1956625B1 (en) Field-effect electron emission structure with emission focussing
FR2704967A1 (en) Flat, microdot screen with doubly-switched anode

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19980421

17Q First examination report despatched

Effective date: 20000118

111Z Information provided on other rights and legal means of execution

Free format text: 20000403 DE FR GB IT

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Designated state(s): DE FR GB IT

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REF Corresponds to:

Ref document number: 69719110

Country of ref document: DE

Date of ref document: 20030327

Kind code of ref document: P

29U Proceedings interrupted after grant according to rule 142 epc

Effective date: 20020621

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030519

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20031202

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20030519

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040130

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050502

RIC2 Information provided on ipc code assigned after grant

Ipc: H01J 31/12 20060101AFI19970628BHEP

29W Proceedings resumed after grant [after interruption of proceedings according to rule 142 epc]

Effective date: 20210201

PUAJ Public notification under rule 129 epc

Free format text: ORIGINAL CODE: 0009425

32PN Public notification

Free format text: NOTIFICATION ETABLIE CONFORMEMENT A LA REGLE 142 CBE (REPRISE DE LA PROCEDURE CONFORMEMENT A LA REGLE 142 (2) CBE EN DATE DU 17.08.2020)

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20211103