EP1647042A2 - Frame/mask assembly for a cathode-ray tube - Google Patents

Frame/mask assembly for a cathode-ray tube

Info

Publication number
EP1647042A2
EP1647042A2 EP04767884A EP04767884A EP1647042A2 EP 1647042 A2 EP1647042 A2 EP 1647042A2 EP 04767884 A EP04767884 A EP 04767884A EP 04767884 A EP04767884 A EP 04767884A EP 1647042 A2 EP1647042 A2 EP 1647042A2
Authority
EP
European Patent Office
Prior art keywords
frame
mask
longitudinal axis
flange
ray tube
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
EP04767884A
Other languages
German (de)
French (fr)
Other versions
EP1647042B1 (en
Inventor
Pedro Cosma
Carlo Tulli
Paolo Ginesti
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.)
Thomson Licensing SAS
Original Assignee
Thomson Licensing SAS
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 Thomson Licensing SAS filed Critical Thomson Licensing SAS
Publication of EP1647042A2 publication Critical patent/EP1647042A2/en
Application granted granted Critical
Publication of EP1647042B1 publication Critical patent/EP1647042B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • 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
    • H01J29/06—Screens for shielding; Masks interposed in the electron stream
    • H01J29/07—Shadow masks for colour television tubes
    • H01J29/073—Mounting arrangements associated with shadow masks
    • 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

Definitions

  • the present invention relates to a color cathode ray tube having a substantially planar screen, and more precisely a frame / mask assembly for selecting colors fitted to such a tube.
  • the invention finds its application in any type of tube comprising a mask for selecting colors, and is more particularly suitable for tubes whose mask is produced by stamping and is held in place inside the tube by a rigid frame on which he is united.
  • a conventional color cathode ray tube is composed of a vacuum glass envelope. The tube has, inside the envelope, a color selection mask located at a precise distance from the glass front face of the tube, front face on which are deposited arrays of red, green and blue phosphors to form a screen.
  • An electron gun is arranged inside the tube, in its rear part, in the direction of the longitudinal axis of the tube, said axis passing through the center of the front face, said gun generating three electron beams in the direction of said front face.
  • An electromagnetic deflection device generally placed outside the tube and close to the electron gun, has the function of deflecting the electron beams in order to make them scan the surface of the panel on which the phosphor networks are arranged. Under the influence of three electron beams each corresponding to a specific primary color, the phosphor networks allow the reproduction of color images on the screen, the mask allowing each determined beam to illuminate only the luminophore of the color. corresponding.
  • the color selection mask must be placed and maintained during the operation of the tube in a precise position inside the tube.
  • the mask holding functions are performed by means of a generally very rigid rectangular metal frame on which the mask is conventionally welded.
  • the frame / mask assembly is mounted in the front face of the tube by means of suspension means welded to the frame and cooperating with pins inserted in the glass constituting the front face of the tube.
  • the color selection mask is produced from a very thin metal sheet and comprises a surface known as an effective surface, pierced with openings, said openings being produced by chemical etching and generally arranged in vertical columns; the effective surface is surrounded by a non-perforated peripheral border; a skirt generally produced by stamping, borders the assembly, extending in a direction substantially perpendicular to the effective surface.
  • the mask is secured to the frame by spot welding at the skirt.
  • the generally rectangular frame has a pair of long sides and a pair of short sides, the cross section of which is generally L-shaped.
  • the frame must have excellent rigidity, allowing the frame / mask assembly to be able to undergo without shape modification the numerous manipulations which occur during the stages of the manufacturing process of a cathode ray tube, as explained in patent US4639230.
  • the frames of the prior art are of thick section and of significant weight, which has two disadvantages: - the final weight of the tube made important by the weight of the frame, which generally reaches at least three times the weight of the mask. - The final cost of the tube due to the high material cost of the frame.
  • a mask formed by stamping exhibited a very significant sensitivity to heating caused by the fact that about 70% of the electrons emitted by the cannon are intercepted by the mask.
  • the cause of this sensitivity lies in the large difference in mass between the frame and the mask, which means that the thermal behavior of two parts is very different for the sets according to the state of the art.
  • the frame according to the invention makes it possible, among other advantages, to reduce the weight of materials used for the manufacture of the frame / mask assembly, while improving the thermal behavior of said assembly.
  • the tube according to the invention comprises: - a front face on which is disposed, on its internal part, a screen of phosphors, - a rear part in the form of a funnel terminated by a cylindrical part in which an electron gun extends in the direction of the longitudinal axis of the tube, axis passing through the center of the front face, - a color selection mask formed by stamping and having a peripheral skirt folded in a direction substantially parallel to the longitudinal axis a frame intended to keep the mask away from the screen, said frame of substantially rectangular shape has at least one pair of parallel sides of substantially L-shaped section with a lateral blank extending in a direction parallel to the longitudinal axis connected to a flange substantially perpendicular to said longitudinal axis said frame being characterized in that said sides of L-shaped section are the short sides of the cad re and in that the width of the flange on each short side is smaller in the middle of the side than at its ends so that the inner edge of the flange defines a curve whose
  • FIG. 1 is a sectional view of a cathode ray tube in color according to the state of the technique
  • Figure 2 is a non-perspective, partially exploded view of a frame / mask assembly for cathode ray tubes according to the prior art
  • Figures 3A, 3B, 3C represent front and side views of '' a frame / mask assembly according to the invention
  • Figures 4A and 4B compare the state of the art and the invention in cross-sectional views of the frame / mask assembly.
  • Figure 1 shows in cross-section the structure of a color cathode ray tube.
  • a frame / mask assembly 20 comprising a shadow mask 21, the curved surface of which is produced by stamping a sheet of steel or invar, a surface which is arranged at a precise distance d 'a phosphor screen 11 arranged on the glass front face 1 of the tube; the mask is held in place by a rigid frame 22 to which it is secured by welding at its peripheral skirt 23 which is folded so as to extend inside the frame in a direction substantially parallel to the longitudinal axis Z
  • the frame itself is rectangular in shape with sides at least partly of L-shaped section, with a flank 24 extending in a direction parallel to the longitudinal axis and a flange 25 substantially perpendicular to this flank; the flange 25 and the flank 24 are connected to each other at the inner edge 26 of the flank furthest from the screen.
  • FIG. 2 illustrates an example of a frame / mask assembly according to the state of the art, as described for example in patent US6064146.
  • the solid frame has a substantially rectangular connecting edge 26 and a flange 25 having a narrower width in the corners of the frame in order to reduce the weight of said frame without modifying its rigidity.
  • the ratio of which is generally greater than or equal to three.
  • FIG. 3A shows a frame 122 according to the invention in a rear view.
  • the substantially rectangular frame has two long sides 121 and two short sides 120.
  • the sides of the frame have a section L-shaped with flanges substantially perpendicular to the longitudinal axis Z, respectively 125 for the short sides and 125 'for the long sides.
  • the flanges are delimited by inner edges, 130 for the short sides, 127 for the long sides, and by outer edges, 131 for the short sides and 126 for the long sides.
  • the sides of the frame also have a flank 124 for the short sides and a side 124 'for the long sides, flank substantially flat and parallel to the longitudinal axis Z.
  • the short sides have a flange whose width varies from the center towards the ends so that the width 150 of said flange in the middle is narrower than the width 151 at its ends. .
  • the interior edges 130 have a concavity turned inward in order to allow the electron beams to intercept a larger part of the surface of the mask skirt which is welded to the frame.
  • FIGS. 4A and 4B show in cross section respectively near the middle of a short side and near its end, the lower limits of the skirt which the electron beams can reach for a frame according to the state of the art (in dotted lines) and according to the invention (in solid lines).
  • the electron beams reach the middle of the short sides at higher angles of incidence in the middle of the frame dimensions than at their ends. So when the flange is of constant width (dotted lines) the mask skirt is less watered by the electron beams in its middle than at its ends, while if its width decreases from its ends towards its center (solid lines) the beams electrons can reach a substantially constant width of the skirt all along the part of the latter welded to the short side of the frame.
  • the inner edge 130 of the flange therefore has a concavity oriented inwardly, with an average radius of curvature less than the average radius of curvature of its outer edge 131.
  • the 16/9 format frame has an inner edge 130 of radius average curvature of approximately 1.1 meters and an outer edge 131 with a radius of curvature of the order of 2.2 meters.
  • the curved shape of the flange provides high mechanical rigidity of the frame, making it possible to obtain a reduction in the amount of metal used to make said frame.
  • the rigidity of the frame / mask assembly can be improved by coupling the curved shape of the flanges on the short sides with flanges on the long sides, on the contrary having a width 160 in its middle greater than its width 161 at its ends.
  • the inner edge 127 of the flange has a concavity turned towards the outside of the frame and the outer edge
  • the thermal behavior of the mask frame assembly is improved as soon as the ratio between the weight of the mask and that of the frame is greater than 0.5 and preferentially tends towards 1.
  • the mask chosen is made of steel with a thickness of 0.25mm, while the frame, in the same material has a thickness of 0.5mm; this results in a mask weighing approximately 340 gr and a frame approximately 450 gr which brings about a mass ratio equal to approximately 0.75.

Landscapes

  • Electrodes For Cathode-Ray Tubes (AREA)

Abstract

The invention relates to a cathode-ray tube with a colour selection mask, comprising a frame (122) for holding the mask remote from the screen. Said frame, having a substantially rectangular shape, has a pair of parallel short sides (120), having a substantially L-shaped section, with a lateral flank (124), which extends in a direction parallel to the longitudinal axis, connected to a flange (125) substantially perpendicular to said longitudinal axis. The flange width at each short side is less in the middle of the side than at the ends thereof, so that the inner edge (130) of the flange defines a curve, the concavity of which is oriented toward the tube longitudinal axis. The frame structure provides an improved thermal behaviour of the frame/mask assembly and a reduced weight of material for production of said frame, while maintaining a sufficient mechanical stiffness.

Description

ENSEMBLE CADRE/MASQUE POUR TUBE A RAYONS CATHODIQUES FRAME / MASK ASSEMBLY FOR TUBE WITH CATHODE RAYS
La présente invention concerne un tube à rayons cathodiques en couleurs ayant un écran sensiblement plan, et plus précisément un ensemble cadre /masque de sélection des couleurs équipant un tel tube. L'invention trouve son application dans tout type de tube comportant un masque de sélection de couleurs, et est plus particulièrement adaptée aux tubes dont le masque est réalisé par emboutissage et est maintenu en place à l'intérieur du tube par un cadre rigide sur lequel il est solidarisé. Un tube à rayons cathodiques en couleurs conventionnel est composé d'une enveloppe en verre sous vide. Le tube comporte à l'intérieur de l'enveloppe, un masque de sélection des couleurs situé à une distance précise de la face avant en verre du tube, face avant sur laquelle sont déposés des réseaux de luminophores rouges, verts et bleus pour former un écran. Un canon à électrons est disposé à l'intérieur du tube, dans sa partie arrière, selon la direction de l'axe longitudinal du tube, ledit axe passant par le centre de la face avant, ledit canon générant trois faisceaux électroniques en direction de ladite face avant. Un dispositif de déflexion électromagnétique, généralement disposé à l'extérieur du tube et proche du canon à électrons a pour fonction de dévier les faisceaux électroniques afin de leur faire balayer la surface du panneau sur laquelle sont disposés les réseaux de luminophores. Sous l'influence de trois faisceaux électroniques correspondants chacun à une couleur primaire déterminée, les réseaux de luminophores permettent la reproduction d'images en couleurs sur l'écran, le masque permettant à chaque faisceau déterminé de n'illuminer que le luminophore de la couleur correspondante. Le masque de sélection des couleurs doit être disposé et maintenu pendant le fonctionnement du tube dans une position précise à l'intérieur du tube. Les fonctions de maintien du masque sont réalisées grâce à un cadre métallique rectangulaire généralement très rigide sur lequel le masque est conventionnellement soudé. L'ensemble cadre/masque est monté dans la face avant du tube grâce des moyens de suspension soudés sur le cadre et coopérant avec des pions insérés dans le verre constituant la face avant du tube. Le masque de sélection des couleurs est réalisé à partir d'une feuille métallique de très faible épaisseur et comporte une surface dite surface effective, percée d'ouvertures, lesdites ouvertures étant réalisées par gravure chimique et généralement disposées en colonnes verticales ; la surface effective est entourée d'une bordure périphérique non ajourée ; une jupe réalisée généralement par emboutissage, borde l'ensemble en s'étendant dans une direction sensiblement perpendiculaire à la surface effective. Le masque est solidarisé au cadre par une soudure par points au niveau de la jupe. Le cadre de forme généralement rectangulaire, possède une paire de cotés longs et une paire de cotés courts, dont la section est généralement en forme de L. Le cadre doit avoir une excellente rigidité, permettant à l'ensemble cadre/masque de pouvoir subir sans modification de forme les nombreuses manipulations qui interviennent durant les étapes du procédé de fabrication d'un tube à rayons cathodiques, comme expliqué dans le brevet US4639230. Pour atteindre ce niveau de rigidité les cadres de l'état de la technique sont de section épaisse et de poids importants ce qui présente deux désavantages : - le poids final du tube rendu important par le poids du cadre qui atteint généralement au moins trois fois le poids du masque. - le coût final du tube du fait de l'important coût matière du cadre Par ailleurs il a été remarqué qu'un masque formé par emboutissage présentait une sensibilité très importante à échauffement causé par le fait qu'environ 70% des électrons émis par le canon sont interceptés par le masque. La cause de cette sensibilité réside dans l'importante différence de masse entre le cadre et le masque, faisant que les comportements thermiques de deux pièces sont, pour les ensembles selon l'état de technique, très différents. Le cadre selon l'invention permet parmi d'autres avantages, de diminuer le poids de matériaux utilisés pour la fabrication de l'ensemble cadre/masque, tout en améliorant le comportement thermique dudit ensemble. Pour cela, le tube selon l'invention comprend : - une face avant sur laquelle est disposé, sur sa partie interne, un écran de luminophores, - une partie arrière en forme d'entonnoir terminé par une partie cylindrique dans laquelle un canon à électrons s'étend dans la direction de l'axe longitudinal du tube, axe passant par le centre de la face avant, - un masque de sélection des couleurs formé par emboutissage et présentant une jupe périphérique pliée dans une direction sensiblement parallèle à l'axe longitudinal - un cadre destiné à maintenir le masque à distance de l'écran, ledit cadre de forme sensiblement rectangulaire possède au moins une paire de cotés parallèles de section sensiblement en forme de L avec un flan latéral s'étendant dans une direction parallèle à l'axe longitudinal relié à un flasque sensiblement perpendiculaire audit axe longitudinal ledit cadre étant caractérisé en ce que lesdits cotés de section en L sont les cotés courts du cadre et en ce que la largeur du flasque de chaque coté court est plus faible au milieu du coté qu'à ses extrémités de manière à ce que le bord intérieur du flasque définisse une courbe dont la concavité est tournée vers l'axe longitudinal du tube. L'invention et ses différents avantages seront mieux compris à l'aide de la description ci-après et des dessins parmi lesquels : - La figure 1 est une vue en coupe d'un tube à rayons cathodiques en couleurs selon l'état de la technique - La figure 2 est une vue ne perspective, partiellement en éclaté d'un ensemble cadre/masque pour tubes à rayons cathodiques selon l'état de la technique - Les figures 3A, 3B, 3C représentent des vues de face et de coté d'un ensemble cadre/masque selon l'invention - Les figures 4A et 4B comparent l'état de la technique et l'invention dans des vues en coupe de l'ensemble cadre/masque La figure 1 montre par une vue en coupe la structure d'un tube à rayons cathodiques en couleurs. Dans un tel tube 10,se trouve un ensemble cadre/masque 20 comprenant un masque d'ombre 21 dont la surface courbe est réalisée par emboutissage d'une feuille d'acier ou d'invar, surface qui est disposée à une distance précise d'un écran de luminophores 11 disposé sur la face avant en verre 1 du tube ; le masque est maintenu en place par un cadre rigide 22 auquel il est solidarisé par soudure au niveau de sa jupe périphérique 23 laquelle est pliée de manière à s'étendre à l'intérieur du cadre dans une direction sensiblement parallèle à l'axe longitudinal Z. Le cadre lui-même est de forme rectangulaire avec des cotés au moins en partie de section en forme de L, avec un flanc 24 s'étendant dans une direction parallèle à l'axe longitudinal et un flasque 25 sensiblement perpendiculaire à ce flanc ; le flasque 25 et le flanc 24 sont reliés l'un à l'autre au niveau du bord intérieur 26 du flanc le plus éloigné de l'écran. Le tube comprend une partie arrière en forme d'entonnoir 30 se terminant par un col cylindrique 31 à l'intérieur duquel se trouve un canon à électrons 40 générant trois faisceaux d'électrons 41 en direction du masque de sélection des couleurs 21.Les faisceau électroniques balaient la surface de l'écran 11 sous l'influence du dispositif de déflexion magnétiques 50. La figure 2 illustre un exemple d'ensemble cadre/masque selon l'état de la technique, comme décrit par exemple dans le brevet US6064146. Le cadre, massif, possède un bord de raccordement 26 sensiblement rectangulaire et un flasque 25 présentant une largeur plus faible dans les coins du cadre afin de diminuer le poids dudit cadre sans modifier sa rigidité. Cependant avec ce type de structure présente une différence importante entre les masses du cadre et du masque dont le rapport est généralement supérieur ou égal à trois. Lorsque le tube fonctionne, environ 20 à 30% des électrons émis par le canon 40 arrivent à traverser le masque par les orifices disposés sur sa surface faisant face à l'écran. Les électrons sont donc en grande partie interceptés par le masque de sélection des couleurs 21 et ils viennent également frapper son cadre support 22. Il en résulte que le cadre et le masque vont subir une dilatation thermique, et lorsque le cadre et le masque sont réalisé dans le même matériau, par exemple en acier, la dilatation du masque va être plus rapide que celle du cadre du fait de l'important différence entre les masses des deux éléments. Le masque, maintenu sur sa périphérie par le cadre, va alors se bomber (phénomène appelé « doming ») et la distance de sa surface à l'écran de luminophore va se modifier jusqu'à ce que l'ensemble atteigne un équilibre thermique. Les modifications de la distance masque 21/écran 11 vont provoquer des décolorations de l'image sur ledit écran les faisceaux d'électrons ne venant plus illuminer correctement les luminophores leur correspondant. Il a découvert que deux facteurs venaient influencer l'apparition de ce phénomène transitoire : - le rapport de masse entre le cadre et l'écran qui doit être inférieur à 2 de manière à minimiser le temps nécessaire à ce que l'ensemble cadre/masque atteigne son équilibre thermique, temps qui est normalement de l'ordre d'une heure et demie - le gradient de température sur la surface du masque, gradient de température qui dans l'état de la technique, fait que la température au centre de l'écran est maximum et est minimum sur les bords. Plus le gradient de température est faible et plus les phénomènes de « doming » sont peu apparents. La température à la périphérie du masque est régie par des conditions aux limites : contacts avec le cadre, inertie thermique du cadre, formes des bords du cadre permettant aux faisceaux électroniques de venir frapper la jupe périphérique pliée 23 du masque. Les figures 3A, 3B, 3C montrent un mode de réalisation d'un ensemble cadre/masque selon l'invention sous différentes vues. La figure 3A montre un cadre 122 selon l'invention dans une vue par l'arrière. Le cadre de forme sensiblement rectangulaire comporte deux cotés longs 121 et deux cotés courts 120. Les cotés du cadre ont une section en forme de L avec des flasques sensiblement perpendiculaires à l'axe longitudinal Z, respectivement 125 pour les cotés courts et 125' pour les cotés longs. Les flasques sont délimités par des bords intérieurs, 130 pour les cotés courts, 127 pour les cotés longs, et par des bords extérieurs, 131 pour les cotés courts et 126 pour les cotés longs. Les cotés du cadre présentent en outre un flanc 124 pour les cotés courts et un flanc 124' pour les cotés longs, flanc sensiblement plan et parallèle à l'axe longitudinal Z. Les cotés courts présentent un flasque dont la largeur varie du centre vers les extrémités de telle manière que la largeur 150 dudit flasque en son milieu soit plus faible que la largeur 151 en ses extrémités. .De cette façon les bords intérieurs130 présentent une concavité tournée vers l'intérieur afin de permettre aux faisceaux d'électrons d'intercepter à une plus grande partie de la surface de la jupe du masque qui est soudée au cadre. Les figures 4A et 4B représentent en coupe transversale respectivement prés du milieu d'un coté court et prés de son extrémité, les limites inférieures de la jupe que peuvent atteindre les faisceaux d'électrons pour un cadre selon l'état de la technique (en pointillés) et selon l'invention (en traits pleins). Les faisceaux électroniques atteignent les milieux des cotés courts sous des angles d'incidences plus élevés au milieu des cotes du cadre qu'à leurs extrémités. Ainsi lorsque le flasque est de largeur constante ( traits pointillés) la jupe du masque est moins arrosée par les faisceaux électroniques en son milieu qu'en ses extrémités, alors que si sa largeur diminue de ses extrémités vers son centre ( traits pleins) les faisceaux d'électrons peuvent atteindre une largeur sensiblement constante de la jupe tout le long de la partie de celle-ci soudée au coté court du cadre. Il en résulte un échauffement mieux réparti du masque avec un gradient de température faible entre les différentes parties du masque. Le bord intérieur 130 du flasque présente donc une concavité orientée vers l'intérieur, avec un rayon de courbure moyen inférieur au rayon de courbure moyen de son bord extérieur 131. Dans un exemple de réalisation selon l'invention destiné à un tube de diagonale d'écran de l'ordre de 60cm, illustré par les figures 3A,3B,3C le cadre de format 16/9 a un bord intérieur 130 de rayon de courbure moyen d'environ 1 ,1 mètres et un bord extérieur 131 de rayon de courbure de l'ordre de 2,2 mètres. La forme cintrée du flasque offre une forte rigidité mécanique du cadre permettant d'obtenir un allégement de la quantité de métal utilisée pour réaliser ledit cadre. La rigidité de l'ensemble cadre/masque peut être amélioré en couplant la forme cintrée des flasques des cotés courts avec des flasques des cotés longs présentant au contraire une largeur 160 en son milieu plus grande que sa largeur 161 en ses extrémités. Dans l'exemple de réalisation selon les figures 3A,3B,3C le bord intérieur 127 du flasque présente une concavité tournée vers l'extérieur du cadre et le bord extérieurThe present invention relates to a color cathode ray tube having a substantially planar screen, and more precisely a frame / mask assembly for selecting colors fitted to such a tube. The invention finds its application in any type of tube comprising a mask for selecting colors, and is more particularly suitable for tubes whose mask is produced by stamping and is held in place inside the tube by a rigid frame on which he is united. A conventional color cathode ray tube is composed of a vacuum glass envelope. The tube has, inside the envelope, a color selection mask located at a precise distance from the glass front face of the tube, front face on which are deposited arrays of red, green and blue phosphors to form a screen. An electron gun is arranged inside the tube, in its rear part, in the direction of the longitudinal axis of the tube, said axis passing through the center of the front face, said gun generating three electron beams in the direction of said front face. An electromagnetic deflection device, generally placed outside the tube and close to the electron gun, has the function of deflecting the electron beams in order to make them scan the surface of the panel on which the phosphor networks are arranged. Under the influence of three electron beams each corresponding to a specific primary color, the phosphor networks allow the reproduction of color images on the screen, the mask allowing each determined beam to illuminate only the luminophore of the color. corresponding. The color selection mask must be placed and maintained during the operation of the tube in a precise position inside the tube. The mask holding functions are performed by means of a generally very rigid rectangular metal frame on which the mask is conventionally welded. The frame / mask assembly is mounted in the front face of the tube by means of suspension means welded to the frame and cooperating with pins inserted in the glass constituting the front face of the tube. The color selection mask is produced from a very thin metal sheet and comprises a surface known as an effective surface, pierced with openings, said openings being produced by chemical etching and generally arranged in vertical columns; the effective surface is surrounded by a non-perforated peripheral border; a skirt generally produced by stamping, borders the assembly, extending in a direction substantially perpendicular to the effective surface. The mask is secured to the frame by spot welding at the skirt. The generally rectangular frame has a pair of long sides and a pair of short sides, the cross section of which is generally L-shaped. The frame must have excellent rigidity, allowing the frame / mask assembly to be able to undergo without shape modification the numerous manipulations which occur during the stages of the manufacturing process of a cathode ray tube, as explained in patent US4639230. To reach this level of rigidity, the frames of the prior art are of thick section and of significant weight, which has two disadvantages: - the final weight of the tube made important by the weight of the frame, which generally reaches at least three times the weight of the mask. - The final cost of the tube due to the high material cost of the frame. Furthermore, it was noted that a mask formed by stamping exhibited a very significant sensitivity to heating caused by the fact that about 70% of the electrons emitted by the cannon are intercepted by the mask. The cause of this sensitivity lies in the large difference in mass between the frame and the mask, which means that the thermal behavior of two parts is very different for the sets according to the state of the art. The frame according to the invention makes it possible, among other advantages, to reduce the weight of materials used for the manufacture of the frame / mask assembly, while improving the thermal behavior of said assembly. For this, the tube according to the invention comprises: - a front face on which is disposed, on its internal part, a screen of phosphors, - a rear part in the form of a funnel terminated by a cylindrical part in which an electron gun extends in the direction of the longitudinal axis of the tube, axis passing through the center of the front face, - a color selection mask formed by stamping and having a peripheral skirt folded in a direction substantially parallel to the longitudinal axis a frame intended to keep the mask away from the screen, said frame of substantially rectangular shape has at least one pair of parallel sides of substantially L-shaped section with a lateral blank extending in a direction parallel to the longitudinal axis connected to a flange substantially perpendicular to said longitudinal axis said frame being characterized in that said sides of L-shaped section are the short sides of the cad re and in that the width of the flange on each short side is smaller in the middle of the side than at its ends so that the inner edge of the flange defines a curve whose concavity is turned towards the longitudinal axis of the tube . The invention and its various advantages will be better understood with the aid of the description below and of the drawings, among which: FIG. 1 is a sectional view of a cathode ray tube in color according to the state of the technique - Figure 2 is a non-perspective, partially exploded view of a frame / mask assembly for cathode ray tubes according to the prior art - Figures 3A, 3B, 3C represent front and side views of '' a frame / mask assembly according to the invention - Figures 4A and 4B compare the state of the art and the invention in cross-sectional views of the frame / mask assembly. Figure 1 shows in cross-section the structure of a color cathode ray tube. In such a tube 10, there is a frame / mask assembly 20 comprising a shadow mask 21, the curved surface of which is produced by stamping a sheet of steel or invar, a surface which is arranged at a precise distance d 'a phosphor screen 11 arranged on the glass front face 1 of the tube; the mask is held in place by a rigid frame 22 to which it is secured by welding at its peripheral skirt 23 which is folded so as to extend inside the frame in a direction substantially parallel to the longitudinal axis Z The frame itself is rectangular in shape with sides at least partly of L-shaped section, with a flank 24 extending in a direction parallel to the longitudinal axis and a flange 25 substantially perpendicular to this flank; the flange 25 and the flank 24 are connected to each other at the inner edge 26 of the flank furthest from the screen. The tube includes a funnel-shaped rear part 30 ending in a cylindrical neck 31 inside which is an electron gun 40 generating three electron beams 41 in the direction of the color selection mask 21. electronics scan the surface of the screen 11 under the influence of the magnetic deflection device 50. FIG. 2 illustrates an example of a frame / mask assembly according to the state of the art, as described for example in patent US6064146. The solid frame has a substantially rectangular connecting edge 26 and a flange 25 having a narrower width in the corners of the frame in order to reduce the weight of said frame without modifying its rigidity. However, with this type of structure, there is an important difference between the masses of the frame and the mask, the ratio of which is generally greater than or equal to three. When the tube is operating, approximately 20 to 30% of the electrons emitted by the barrel 40 arrive to pass through the mask through the orifices arranged on its surface facing the screen. The electrons are therefore largely intercepted by the color selection mask 21 and they also strike its support frame 22. As a result, the frame and the mask will undergo thermal expansion, and when the frame and the mask are made of the same material, for example in steel, the expansion of the mask will be faster than that of the frame due to the significant difference between the masses of the two elements. The mask, held on its periphery by the frame, will then bulge (phenomenon called "doming") and the distance from its surface to the phosphor screen will change until the assembly reaches thermal equilibrium. The modifications of the mask 21 / screen 11 distance will cause discoloration of the image on said screen, the electron beams no longer correctly illuminating the phosphors corresponding to them. He discovered that two factors influenced the appearance of this transient phenomenon: - the mass ratio between the frame and the screen which must be less than 2 so as to minimize the time necessary for the frame / mask assembly reaches its thermal equilibrium, time which is normally of the order of an hour and a half - the temperature gradient on the surface of the mask, temperature gradient which in the state of the art, causes the temperature at the center of the screen is maximum and is minimum at the edges. The lower the temperature gradient, the less apparent the doming phenomena. The temperature at the periphery of the mask is governed by boundary conditions: contact with the frame, thermal inertia of the frame, shapes of the edges of the frame allowing the electron beams to strike the folded peripheral skirt 23 of the mask. Figures 3A, 3B, 3C show an embodiment of a frame / mask assembly according to the invention in different views. FIG. 3A shows a frame 122 according to the invention in a rear view. The substantially rectangular frame has two long sides 121 and two short sides 120. The sides of the frame have a section L-shaped with flanges substantially perpendicular to the longitudinal axis Z, respectively 125 for the short sides and 125 'for the long sides. The flanges are delimited by inner edges, 130 for the short sides, 127 for the long sides, and by outer edges, 131 for the short sides and 126 for the long sides. The sides of the frame also have a flank 124 for the short sides and a side 124 'for the long sides, flank substantially flat and parallel to the longitudinal axis Z. The short sides have a flange whose width varies from the center towards the ends so that the width 150 of said flange in the middle is narrower than the width 151 at its ends. .In this way the interior edges 130 have a concavity turned inward in order to allow the electron beams to intercept a larger part of the surface of the mask skirt which is welded to the frame. FIGS. 4A and 4B show in cross section respectively near the middle of a short side and near its end, the lower limits of the skirt which the electron beams can reach for a frame according to the state of the art (in dotted lines) and according to the invention (in solid lines). The electron beams reach the middle of the short sides at higher angles of incidence in the middle of the frame dimensions than at their ends. So when the flange is of constant width (dotted lines) the mask skirt is less watered by the electron beams in its middle than at its ends, while if its width decreases from its ends towards its center (solid lines) the beams electrons can reach a substantially constant width of the skirt all along the part of the latter welded to the short side of the frame. This results in a better distributed heating of the mask with a low temperature gradient between the different parts of the mask. The inner edge 130 of the flange therefore has a concavity oriented inwardly, with an average radius of curvature less than the average radius of curvature of its outer edge 131. In an exemplary embodiment according to the invention intended for a tube of diagonal d screen of the order of 60 cm, illustrated by FIGS. 3A, 3B, 3C the 16/9 format frame has an inner edge 130 of radius average curvature of approximately 1.1 meters and an outer edge 131 with a radius of curvature of the order of 2.2 meters. The curved shape of the flange provides high mechanical rigidity of the frame, making it possible to obtain a reduction in the amount of metal used to make said frame. The rigidity of the frame / mask assembly can be improved by coupling the curved shape of the flanges on the short sides with flanges on the long sides, on the contrary having a width 160 in its middle greater than its width 161 at its ends. In the exemplary embodiment according to FIGS. 3A, 3B, 3C the inner edge 127 of the flange has a concavity turned towards the outside of the frame and the outer edge
126 présente une concavité tournée vers l'intérieur. Les rayons de courbures des bords extérieur et intérieur sont respectivement de l'ordre de 7m et 7,3m. Bien que le type de structure de cadre selon l'invention puisse être adapté à tous les types de moyens de suspensions dans le tube de l'ensemble cadre/masque, la rigidité dudit ensemble, une fois inséré dans le tube est améliorée par des moyens de suspensions disposés dans les coins. Ainsi des ressorts de suspensions peuvent être disposés dans les coins 140 du cadre pour coopérer avec des pions 2 insérés dans la jupe en verre de la partie avant 1 du tube. De cette manière il est à la fois possible de diminuer la quantité de matière utilisée pour réaliser le cadre et d'utiliser un ensemble cadre/masque en acier, matériau moins coûteux que linvar. Dans le mode de réalisation selon la figure 3A à 3C, on a remarqué que le comportement thermique de l'ensemble cadre masque était amélioré dès que le rapport entre le poids du masque et celui du cadre était supérieur à 0,5 et tendait préférentiellement vers 1. Ainsi pour un tube de diagonale d'écran de 60cm, de format 16/9, le masque choisi est en acier d'épaisseur 0.25mm, alors que le cadre, dans le même matériau a une épaisseur de 0.5mm ; il en résulte un masque pesant environ 340 gr et un cadre environ 450 gr ce qui amène un rapport de masse égal à environ 0,75. 126 has a concavity facing inward. The radii of curvature of the outer and inner edges are respectively of the order of 7m and 7.3m. Although the type of frame structure according to the invention can be adapted to all types of suspension means in the tube of the frame / mask assembly, the rigidity of said assembly, once inserted into the tube is improved by means of suspensions arranged in the corners. Thus suspension springs can be arranged in the corners 140 of the frame to cooperate with pins 2 inserted in the glass skirt of the front part 1 of the tube. In this way it is both possible to reduce the amount of material used to make the frame and to use a frame / mask assembly made of steel, a less expensive material than linvar. In the embodiment according to FIG. 3A to 3C, it has been noted that the thermal behavior of the mask frame assembly is improved as soon as the ratio between the weight of the mask and that of the frame is greater than 0.5 and preferentially tends towards 1. Thus for a screen diagonal tube of 60cm, in 16/9 format, the mask chosen is made of steel with a thickness of 0.25mm, while the frame, in the same material has a thickness of 0.5mm; this results in a mask weighing approximately 340 gr and a frame approximately 450 gr which brings about a mass ratio equal to approximately 0.75.

Claims

REVENDICATIONS
1/ Tube à rayons cathodiques comprenant : - une face avant (1) sur laquelle est disposé, sur sa partie interne, un écran de luminophores (11), - une partie arrière en forme d'entonnoir (30) terminée par une partie cylindrique (31) dans laquelle un canon à électrons (40) s'étend dans la direction de l'axe longitudinal Z du tube, axe passant par le centre de la face avant, - un masque de sélection des couleurs (21) formé par emboutissage et présentant une jupe périphérique pliée dans une direction sensiblement parallèle à l'axe longitudinal - un cadre (122) destiné à maintenir le masque à distance de l'écran, ledit cadre de forme sensiblement rectangulaire possède au moins une paire de cotés parallèles (120) de section sensiblement en forme de L avec un flan latéral (124) s'étendant dans une direction parallèle à l'axe longitudinal relié à un flasque (125) sensiblement perpendiculaire audit axe longitudinal ledit cadre étant caractérisé en ce que lesdits cotés de section en L sont les cotés courts du cadre et en ce que la largeur du flasque de chaque coté court est plus faible au milieu du coté qu'à ses extrémités de manière à ce que le bord intérieur (130) du flasque définisse une courbe dont la concavité est tournée vers l'axe longitudinal du tube 2/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que les cotés longs du cadre comprennent une section en L et en ce que la largeur du flasque (125') de chaque coté long est plus importante au milieu dudit coté qu'à ses extrémités 3/ Tube à rayons cathodiques selon la revendication 2 caractérisé en ce que le bord intérieur (127) dudit flasque définisse une courbe dont la concavité est tournée vers l'extérieur du cadre. 4/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que le masque est en acier 5/ Tube à rayons cathodiques selon la revendication 2 caractérisé en ce que le poids du cadre est inférieur à deux fois le poids du masque.1 / Cathode ray tube comprising: - a front face (1) on which is disposed, on its internal part, a screen of phosphors (11), - a rear part in the form of a funnel (30) terminated by a cylindrical part (31) in which an electron gun (40) extends in the direction of the longitudinal axis Z of the tube, axis passing through the center of the front face, - a color selection mask (21) formed by stamping and having a peripheral skirt folded in a direction substantially parallel to the longitudinal axis - a frame (122) intended to keep the mask away from the screen, said substantially rectangular frame has at least one pair of parallel sides (120 ) of substantially L-shaped section with a lateral blank (124) extending in a direction parallel to the longitudinal axis connected to a flange (125) substantially perpendicular to said longitudinal axis said frame being characterized in that said c ot the L-shaped section are the short sides of the frame and in that the width of the flange on each short side is narrower in the middle of the side than at its ends so that the inner edge (130) of the flange defines a curve whose concavity is turned towards the longitudinal axis of the tube 2 / cathode ray tube according to claim 1 characterized in that the long sides of the frame comprise an L-shaped section and in that the width of the flange (125 ') of each long side is greater in the middle of said side than at its ends 3 / cathode ray tube according to claim 2 characterized in that the inner edge (127) of said flange defines a curve whose concavity is turned towards the outside of the frame. 4 / cathode ray tube according to claim 1 characterized in that the mask is made of steel 5 / cathode ray tube according to claim 2 characterized in that the weight of the frame is less than twice the weight of the mask.
6/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que le bord de raccordement (131) du flasque (125) au flanc latéral définisse une courbe dont la concavité est tournée vers l'axe longitudinal du tube6 / cathode ray tube according to claim 1 characterized in that the connecting edge (131) of the flange (125) to the lateral flank defines a curve whose concavity is turned towards the longitudinal axis of the tube
7/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que l'ensemble cadre/masque est maintenu à l'intérieur du tube par des moyens de support disposés aux coins ( 140) du cadre. 7 / cathode ray tube according to claim 1 characterized in that the frame / mask assembly is held inside the tube by support means disposed at the corners (140) of the frame.
EP04767884A 2003-07-18 2004-07-09 Frame/mask assembly for a cathode-ray tube Expired - Lifetime EP1647042B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT001473A ITMI20031473A1 (en) 2003-07-18 2003-07-18 SQUARE-MASK GROUP FOR CATHODIC RAYS TUBE
PCT/FR2004/050323 WO2005010915A2 (en) 2003-07-18 2004-07-09 Frame/mask assembly for a cathode-ray tube

Publications (2)

Publication Number Publication Date
EP1647042A2 true EP1647042A2 (en) 2006-04-19
EP1647042B1 EP1647042B1 (en) 2007-05-30

Family

ID=34090509

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04767884A Expired - Lifetime EP1647042B1 (en) 2003-07-18 2004-07-09 Frame/mask assembly for a cathode-ray tube

Country Status (8)

Country Link
US (1) US20070007873A1 (en)
EP (1) EP1647042B1 (en)
JP (1) JP2006528404A (en)
KR (1) KR20060034296A (en)
CN (1) CN1813330A (en)
DE (1) DE602004006754T2 (en)
IT (1) ITMI20031473A1 (en)
WO (1) WO2005010915A2 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100624992B1 (en) * 2004-06-26 2006-09-20 엘지.필립스 디스플레이 주식회사 Cathode Ray Tube
KR100863972B1 (en) * 2007-09-13 2008-10-16 삼성에스디아이 주식회사 Cathode ray tube
US8860551B2 (en) 2009-03-23 2014-10-14 International Business Machines Corporation Automated RFID reader detection
USD980410S1 (en) * 2020-07-10 2023-03-07 Lg Electronics Inc. Filter housing for mask type air purifier
CN112323018B (en) * 2020-11-02 2022-12-13 昆山工研院新型平板显示技术中心有限公司 Reticle frame and reticle assembly

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5742116A (en) * 1994-10-28 1998-04-21 Matsushita Electronics Corporation Shadow mask frame structure with long-sides having higher mechanical strength
TW328605B (en) * 1996-03-11 1998-03-21 Hitachi Ltd The color cathode tube
US6188170B1 (en) * 1996-07-12 2001-02-13 Kabushiki Kaisha Toshiba Color cathode ray tube including mask frame with protruding portions
DE19757357C2 (en) * 1996-12-30 2001-12-06 Samsung Display Devices Co Ltd Shadow mask assembly for a color cathode ray tube
KR100428968B1 (en) * 1997-07-04 2004-07-16 삼성에스디아이 주식회사 Shadow mask frame assembly for color cathode ray tube, including frame having support portion, flange portion and skirt portion
KR20010081639A (en) * 2000-02-17 2001-08-29 구자홍 Support frame for a cathod ray tube
CN1346139A (en) * 2000-09-25 2002-04-24 三星Sdi株式会社 Shadow mask assembly and clour kinescope installed same
US6781297B2 (en) * 2001-04-07 2004-08-24 Thomson Licensing S. A. Method and apparatus for maintaining mask strand spatial uniformity
KR100414481B1 (en) * 2001-04-21 2004-01-07 엘지전자 주식회사 The Frame for Color Cathode-ray Tube Having Tension Type Shadow Mask
US6680563B2 (en) * 2001-06-27 2004-01-20 Thomson Licensing S.A. Color picture tube having a low expansion tension mask attached to a higher expansion frame
US6600258B2 (en) * 2001-10-29 2003-07-29 Thomson Licensing S.A. Tension mask for a cathode-ray-tube
KR20030095623A (en) * 2002-06-12 2003-12-24 삼성에스디아이 주식회사 Mask assembly for cathode ray tube
JP2004296378A (en) * 2003-03-28 2004-10-21 Mitsubishi Electric Corp Frame for color selection electrode body structure, color selection electrode body structure, and manufacturing method of color selection electrode body structure

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005010915A2 *

Also Published As

Publication number Publication date
WO2005010915A3 (en) 2005-09-15
DE602004006754D1 (en) 2007-07-12
CN1813330A (en) 2006-08-02
DE602004006754T2 (en) 2008-01-31
EP1647042B1 (en) 2007-05-30
JP2006528404A (en) 2006-12-14
KR20060034296A (en) 2006-04-21
ITMI20031473A1 (en) 2005-01-19
WO2005010915A2 (en) 2005-02-03
US20070007873A1 (en) 2007-01-11

Similar Documents

Publication Publication Date Title
EP0145570B1 (en) Shadow mask for a colour picture tube, and tube provided with such a mask
FR2702881A1 (en) Colour cathode-ray tube containing a perforated mask in which holes are arranged with a pitch which does not decrease monotonically
FR2541817A1 (en) CATHODE RAY TUBE WITH IMPROVED SHADOW MASK CONTOUR
FR2541820A1 (en) CATHODE RAY TUBE HAVING A FRONT PLATE PANEL HAVING A SUBSTANTIALLY FLAT PERIPHERAL
FR2477316A1 (en) COLOR IMAGE TUBE HAVING ONLINE ELECTRONIC GUNS
EP1647042B1 (en) Frame/mask assembly for a cathode-ray tube
FR2545647A1 (en) TUBE WITH CATHODE RAYS COMPRISING A SCREEN GRID, AND ASTIGMATIC GRID FOR SUCH A TUBE
FR2631162A1 (en) COLOR IMAGE TUBE AND MANUFACTURING METHOD THEREOF
FR2551582A1 (en) CATHODE RAY TUBE HAVING A FLAT PERIPHERAL FRONT PLATE
FR2705164A1 (en) Colour image tube with linear electron guns having astigmatic lenses
WO2006072719A1 (en) Shadow mask structure for cathode ray tube
EP0145569B1 (en) Shadow mask for a colour picture tube, and tube provided with such a mask
EP1719149A2 (en) Support means of a frame/mask assembly for cathode ray tubes
WO2004068528A2 (en) Colour cathode ray tube with essentially flat screen
WO2006090077A2 (en) Colour cathode ray tube mask
FR2766612A1 (en) DEVIATOR FOR CATHODE RAY TUBES WITH IMPROVED GEOMETRY AND CONVERGENCE
WO2004051693A2 (en) Support for colour cathode ray tube frame/mask assembly
WO2006054014A1 (en) Frame/mask assembly for a cathode ray tube
WO2005027173A2 (en) Anti-implosion device for a cathode ray tube
WO2004017354A2 (en) Colour cathode ray tubes comprising a colour selection mask
WO2006054013A1 (en) Anti-implosion band for cathode ray tube
WO2006040488A1 (en) Glass case for cathode ray tubes
WO2005024887A2 (en) Device for fixing an internal magnetic screen to a frame
FR2791468A1 (en) DEVIATION UNIT FOR SELF-CONVERGING CATHODE RAY TUBE WITH REDUCED TRAPEZE DIFFERENTIAL
FR2824184A1 (en) COLORED CATHODE RAY TUBE WITH INTERNAL MAGNETIC SHIELD

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

17P Request for examination filed

Effective date: 20051229

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

DAX Request for extension of the european patent (deleted)
RBV Designated contracting states (corrected)

Designated state(s): DE FR GB IT

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

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: 602004006754

Country of ref document: DE

Date of ref document: 20070712

Kind code of ref document: P

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20070705

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: 20080303

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20080711

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20080729

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20080630

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20090722

Year of fee payment: 6

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

Effective date: 20090709

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: 20090709

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: 20100202

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: 20090709

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20110331

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: 20100802