WO2004097887A1 - Front face for a cathode ray tube - Google Patents

Front face for a cathode ray tube Download PDF

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Publication number
WO2004097887A1
WO2004097887A1 PCT/FR2004/050164 FR2004050164W WO2004097887A1 WO 2004097887 A1 WO2004097887 A1 WO 2004097887A1 FR 2004050164 W FR2004050164 W FR 2004050164W WO 2004097887 A1 WO2004097887 A1 WO 2004097887A1
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WO
WIPO (PCT)
Prior art keywords
cathode ray
ray tube
front face
panel
tube according
Prior art date
Application number
PCT/FR2004/050164
Other languages
French (fr)
Inventor
Gildo Di Domenico
Paolo Romani
Gianfranco Briganti
Original Assignee
Thomson Licensing S.A.
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 S.A. filed Critical Thomson Licensing S.A.
Publication of WO2004097887A1 publication Critical patent/WO2004097887A1/en

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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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • 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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/863—Vessels or containers characterised by the material thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/86—Vessels and containers
    • H01J2229/8613—Faceplates

Definitions

  • the present invention relates to a cathode ray tube and more particularly to the transparent front face of said tube.
  • the invention finds its application in any type of tube comprising a mask for selecting colors and is as well suited to tubes whose mask is produced by stamping and held by a rigid frame, as to tubes whose mask is kept in tension by the frame itself.
  • a conventional color cathode ray tube is composed of a vacuum glass envelope composed of a front face serving as a screen and a rear part in the form of a funnel.
  • 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 placed inside the tube, in its rear part generates three electron beams in the direction of the front face.
  • An electromagnetic deflection device generally placed outside the tube on the rear part in the form of a funnel, has the function of deflecting the electron beams of the electron gun in order to make them sweep the surface of the panel on which the phosphor networks. Under the influence of three electron beams, each corresponding to a specific primary color, the phosphor networks allow the reproduction of images on the screen, the mask allowing at each determined beam to illuminate only the phosphor of the corresponding color.
  • the tubes whose front face is more and more flat correspond to the current trend, until evolving towards completely flat front faces.
  • the visibility for the spectator of an image formed on the screen of the tube is influenced by the shape of the glass front face of the tube, and in particular by the internal and external surfaces of said front face.
  • the internal surface may have curvatures in particular to ensure the mechanical strength of the glass envelope, curvatures causing excess thickness of glass.
  • the tubes whose mask is formed by stamping are particularly sensitive to this type of drawbacks; in fact the surface of the internal part of the front face and therefore of the screen has a curvature substantially identical to the curvature of the surface of the mask which is generally generally very curved for reasons of mechanical strength: the color selection mask such a tube has a surface defined by horizontal and vertical profiles whose radii of curvature are small, of the order of one or two meters, especially in areas near the edges of the screen.
  • One of the objects of the invention is to provide a solution to these problems by reducing, for example, the weight and the cost of the raw materials used for manufacturing the front face of the tube as well as the final manufacturing cost of the tube.
  • a cathode ray tube comprises a vacuum enclosure formed by a panel composed of a front face serving as a support for a luminescent screen, and of a rear part in the form of a funnel, said tube being characterized in that said front face is formed by at least two layers of materials joined to each other, each of the two layers representing at least 15% of the total weight of the panel.
  • FIG. 1 illustrates in a perspective view, partially exploded, a cathode ray tube and its essential elements
  • FIG. 2 illustrates a front view of a front face of a cathode ray tube according to the state of the art
  • Figure 3 shows a sectional view of a cathode ray tube according to a first embodiment of the invention.
  • Figure 4 shows a sectional view of a panel for cathode ray tubes according to a second embodiment of the invention.
  • Figure 5 illustrates an embodiment of a suspension system of a cathode ray tube according to the second embodiment of the invention.
  • Figure 1 shows in a sectional view a cathode ray tube in which the essential elements of said tube are visible.
  • the tube comprises a panel 8 comprising a front face 1 on the internal surface of which is deposited a screen formed of networks of luminescent materials, a rear part 6 in the form of a funnel, a substantially cylindrical neck 4 inside which is installed an electron gun 2.
  • the panel may include a peripheral skirt 5 connecting the front face to the rear part 6.
  • a color selection mask 10 is installed between the electron gun and the screen and is curved so that its surface corresponds to the internal surface of the front face 1.
  • FIG. 2 illustrates a method according to the state of the art for improving the mechanical strength of the tube while reducing the thickness of glass used.
  • an organic polymer film 16 which may have several layers 13, 14, 15 ... is bonded to the front face 12 of the tube with cathode rays 11.
  • This film has a thickness of between 25 ⁇ m and 500 ⁇ m and makes it possible to reduce the thickness of glass by approximately 2%.
  • FIG. 3 illustrates a first embodiment of the invention.
  • the cathode ray tube 20 comprises a vacuum glass envelope composed of a substantially cylindrical neck 25, a flared rear part 24, in the form of a funnel, and a panel 29 comprising a front face 26, said panel being sealed on its periphery at the edge of the flared portion.
  • a mask 23 is maintained inside the tube when the tube is intended to reproduce color images.
  • the front face 26 is composed of two parts, a substantially planar external part 21, of substantially constant thickness and an internal part 22 adhering on one side to the external part and has an internal surface 28 on which is deposited 1 ' fluorescent screen 27.
  • the internal surface 28 is curved so that the curvatures of said surface and that of the mask are matched in a conventional manner.
  • the external part 21 of the front face can be made of inexpensive glass because it can be flat and of substantially constant thickness.
  • a float glass, of the type for manufacturing glazing, can advantageously be used.
  • Part 22 which is more complex to produce, can be produced in the conventional manner by pressing a drop of molten glass.
  • the weight of the glass of the internal part 22 must be reduced as much as possible relative to the weight of the external part.
  • a front face whose external surface is substantially flat has significant differences in thickness between the center and the edges, differences which are fully transferred to the internal part 22.
  • the internal part represents 20% to 45% of the weight of the panel 29 depending on the tube sizes and the internal curvature of the internal part 22 of the front face.
  • This type of structure also has other advantages.
  • the front faces of current tubes have a low light transmission coefficient in order to increase the contrast of the image formed on the tube screen.
  • This market demand requires the use of dark glasses to produce the glass surface of the panel supporting the screen.
  • the transmission of the panel is very different between the center and the edges resulting in differences in image brightness very visible to the viewer.
  • additional methods such as films applied to the external surface of the screen to standardize the brightness of the image, thereby reducing the manufacturing costs of the tube.
  • FIG. 4 shows a front face 126, comprising an inner layer of glass 22, an intermediate layer 21 also of glass and an outer layer 121 of polymer-based material, for example poly carbonate.
  • the outer layer is secured to the two glass layers 21 and 22 when the tube is finished until the vacuum of said enclosure; indeed, steps of the process for manufacturing said enclosure carried out at high temperature would not be bearable by the layer of polymer-based material.
  • the thickness of the intermediate glass layer will be chosen to a minimum value and the layer 121 to a maximum value to minimize the total weight of glass used.
  • the panel 39 also includes a front face 35 in two parts, an inner part 32 serving to support the fluorescent screen 37 covered by an outer part 31.
  • the two parts 31 and 32 are made of different materials:
  • an inert material for the inner part for example glass - a lighter and less expensive material for the outer part 31, this material can be any material based on organic polymer having sufficient mechanical strength; poly carbonate, taking into account its mechanical strength and its low cost, can advantageously be chosen like other materials, for example polyurethane or resins, for example resins based on aramid.
  • the panel 39 has a front face 35 surrounded by a peripheral skirt 38 extending substantially perpendicular to this front face.
  • the edge 34 of the skirt serves as a connection zone to the rear part of the funnel-shaped tube.
  • the front face 35 comprises an inner layer of glass 32 and an outer layer 31 of poly carbonate.
  • the outer layer may or may not extend at least in part in the zone constituting the peripheral skirt 38.
  • the following table highlights the advantages of a panel produced according to the invention; for a tube whose outer surface of the panel is substantially planar, with a screen diagonal equal to 68 cm and a screen format 4 by 3, the overall weight of the panel produced in one piece of glass is 21 Kg; according to the invention the overall size of the panel is reduced by approximately 15% and the weight of the glass by approximately 55%.
  • the tube is manufactured in the following way:
  • the manufacturing method is a largely conventional method in which the rear funnel-shaped part 24 is sealed to the glass part 32 of the panel at the sealing edge 34; after sealing the barrel in the tube, the air inside it is pumped until a vacuum of about 1 ⁇ "6 atmosphere is reached.
  • the front face must be able to withstand empty, which requires a minimum thickness of glass which cannot be below 40% of the thickness of a front panel according to the prior art to avoid risks of implosion.
  • the outer part 31 is then placed on the glass surface of the part 32 and is made integral with said part 32 by means of an adhesive placed between the two surfaces.
  • This adhesive can be an epoxy-based adhesive, if 1 icon ...
  • This adhesive can contain agents reacting to ultraviolet rays to perfect the adhesion of the two parts 31 and 32.
  • the final assembly phase includes the provision on the skirt of the tube of the anti-implosion belt compressing the lateral part of the tube.
  • the internal part is of substantially constant thickness while the external part 31 is thicker in the corners relative to the center of the screen. This constant thickness of the glass part is a factor in reducing the manufacturing costs of the panel 35.
  • the external part 31 of polymer-based material may be of constant thickness and the internal part of glass 31 thicker in the corners of the panel.
  • the part of constant thickness has a lower coefficient (to improve the contrast of the image) than the part of variable thickness which will be chosen as transparent as possible.
  • This embodiment also makes it possible to include in the outer part, base of polymer materials 31, the metal ears 40 for fixing the tube to inside the housing of the television receiver, which avoids the step of welding said ears to the surface of the anti-implosion strip, generally carried out near the corners of said belt.
  • the panel 35 can be composed of more than 2 layers of materials secured to each other.
  • the panel can for example be composed of two glass layers each of the two layers representing at least 20% of the total weight of the panel, sandwi sing a layer of polymer-based material.
  • the panel is composed of two layers representing at least 20% of the total weight of the panel, one in glass and one in polymer-based material, the outer layer being covered by a film of polymeric material intended to control the transmission of the panel or reduce the reflection of light on the surface of said panel.

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  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)

Abstract

The invention relates to a cathode ray tube comprising a vacuum enclosure, formed by a panel (29, 39) with a front face (26, 35) which supports a luminescent screen (27, 37) and by a rear section in the form of a bell (24). Said front face comprises at least two layers (21, 22; 31, 32) of materials fixed to each other, each of the two layers being at least 20 % of the total weight of the panel. The above structure permits a lightening of the tube and a reduction in production costs.

Description

FACE AVANT POUR TUBE A RAYONS CATHODIQUES FRONT PANEL FOR CATHODE RAY TUBE
La présente invention se rapporte à un tube à rayons cathodiques et plus particulièrement à la face avant transparente dudit tube.The present invention relates to a cathode ray tube and more particularly to the transparent front face of said tube.
L'invention trouve son application dans tout type de tube comportant un masque de sélection de couleurs et est aussi bien adaptée aux tubes dont le masque est réalisé par emboutissage et maintenu par un cadre rigide, qu'aux tubes dont le masque est maintenu en tension par le cadre lui -même.The invention finds its application in any type of tube comprising a mask for selecting colors and is as well suited to tubes whose mask is produced by stamping and held by a rigid frame, as to tubes whose mask is kept in tension by the frame itself.
Un tube à rayons cathodiques en couleurs conventionnel est composé d'une enveloppe en verre sous vide composée d'une face avant servant d'écran et d'une partie arrière en forme d'entonnoir. 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 disposé à l'intérieur du tube, dans sa partie arrière, génère trois faisceaux électroniques en direction de la face avant. Un dispositifs de déflexion électromagnétique, généralement disposé à 1 'extérieur du tube sur la partie arrière en forme d'entonnoir, a pour fonction de dévier les faisceaux électroniques du canon à électrons 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 sur l'écran, le masque permettant à chaque faisceau déterminé de n'illuminer que le luminophore de la couleur correspondante.A conventional color cathode ray tube is composed of a vacuum glass envelope composed of a front face serving as a screen and a rear part in the form of a funnel. 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 placed inside the tube, in its rear part, generates three electron beams in the direction of the front face. An electromagnetic deflection device, generally placed outside the tube on the rear part in the form of a funnel, has the function of deflecting the electron beams of the electron gun in order to make them sweep the surface of the panel on which the phosphor networks. Under the influence of three electron beams, each corresponding to a specific primary color, the phosphor networks allow the reproduction of images on the screen, the mask allowing at each determined beam to illuminate only the phosphor of the corresponding color.
Les tubes dont la face avant est de plus en plus plane correspondent à la tendance actuelle, jusqu'à évoluer vers des faces avant totalement planes. La visibilité pour le spectateur, d'une image formée sur l'écran du tube est influencée par la forme de la face avant en verre du tube, et en particulier par les surfaces interne et externe de ladite face avant. Dans le cas d'un tube présentant une face avant dont la surface extérieure est sensiblement plane, la surface interne peut présenter des courbures en particulier pour assurer la résistance mécanique de l'enveloppe en verre, courbures entraînant des surépaisseurs de verre. Ces surépaisseurs sont visibles par le spectateur dans la mesure ou le coefficient de transmission de la lumière dépend de l'épaisseur de la face avant, surtout quand le verre utilisé est sombre pour augmenter le contraste de l'image formée sur l'écran.The tubes whose front face is more and more flat correspond to the current trend, until evolving towards completely flat front faces. The visibility for the spectator of an image formed on the screen of the tube is influenced by the shape of the glass front face of the tube, and in particular by the internal and external surfaces of said front face. In the case of a tube having a front face, the external surface of which is substantially flat, the internal surface may have curvatures in particular to ensure the mechanical strength of the glass envelope, curvatures causing excess thickness of glass. These extra thicknesses are visible to the viewer to the extent that the light transmission coefficient depends on the thickness of the front face, especially when the glass used is dark to increase the contrast of the image formed on the screen.
Par ailleurs ces surépaisseurs augmente le poids de verre utilisé rendant la manipulation des tubes de grande dimension difficile et augmentant notablement le coût de la matière première utilisée.In addition, these extra thicknesses increase the weight of glass used, making the handling of large tubes difficult and significantly increasing the cost of the raw material used.
Les tubes dont le masque est formé par emboutissage sont particulièrement sensibles à ce type d'inconvénients ; en effet la surface de la partie interne de la face avant et donc de l'écran a une courbure sensiblement identique à la courbure de la surface du masque qui est généralement généralement très courbée pour des raisons de tenue mécanique : le masque de sélection des couleurs d'un tel tube a une surface définie par des profils horizontaux et verticaux dont les rayons de courbures sont faibles, de l'ordre de un ou deux mètres , en particulier dans les zones situées prés des bords de 1 'écran.The tubes whose mask is formed by stamping are particularly sensitive to this type of drawbacks; in fact the surface of the internal part of the front face and therefore of the screen has a curvature substantially identical to the curvature of the surface of the mask which is generally generally very curved for reasons of mechanical strength: the color selection mask such a tube has a surface defined by horizontal and vertical profiles whose radii of curvature are small, of the order of one or two meters, especially in areas near the edges of the screen.
Afin de pallier ces inconvénients il a été proposé comme indiqué dans le brevet US6111352 de déposer sur la surface externe de la face avant un film plastique de faible épaisseur. Cependant cette technique ne permet pas de diminuer notablement le poids de verre utilisé. Par ailleurs, comme le film est déposé dans les étapes finales du procédé de fabrication, un défaut de surface du à un problème d'application du film sur la face avant peut entraîner le rejet du tube.In order to overcome these drawbacks, it has been proposed, as indicated in patent US Pat. No. 6,111,352, to deposit on the external surface of the front face a thin plastic film. However, this technique does not make it possible to significantly reduce the weight of glass used. Furthermore, as the film is deposited in the final stages of the manufacturing process, a surface defect due to a problem of application of the film on the front face can lead to rejection of the tube.
Un des objets de l'invention est d'apporter une solution à ces problèmes en diminuant par exemple le poids et le coût des matières premières utilisées pour la fabrication de la face avant du tube ainsi que le coût de fabrication final du tube.One of the objects of the invention is to provide a solution to these problems by reducing, for example, the weight and the cost of the raw materials used for manufacturing the front face of the tube as well as the final manufacturing cost of the tube.
Pour cela, un tube à rayons cathodiques selon l'invention comprend une enceinte sous vide formée par un panneau composé d'une face avant servant de support à un écran luminescent, et d'une partie arrière en forme d'entonnoir, ledit tube étant caractérisé en ce que ladite face avant est formée par au moins deux couches de matériaux solidarisées l'une à l'autre, chacune des deux couches représentant au moins 15% du poids total du panneau.For this, a cathode ray tube according to the invention comprises a vacuum enclosure formed by a panel composed of a front face serving as a support for a luminescent screen, and of a rear part in the form of a funnel, said tube being characterized in that said front face is formed by at least two layers of materials joined to each other, each of the two layers representing at least 15% of the total weight of the panel.
L'invention et ses différents avantages seront mieux compris à l'aide de la description détaillée ci -après et des dessins parmi lesquels :The invention and its various advantages will be better understood with the aid of the detailed description below and of the drawings, among which:
- la figure 1 illustre par une vue en perspective, partiellement en éclaté, un tube à rayons cathodiques et ses éléments essentiels La figure 2 illustre par une vue de face une face avant d'un tube à rayons cathodique selon 1 'état de la technique- Figure 1 illustrates in a perspective view, partially exploded, a cathode ray tube and its essential elements FIG. 2 illustrates a front view of a front face of a cathode ray tube according to the state of the art
La figure 3 montre par une vue en coupe d'un tube à rayons cathodiques selon un premier mode de réalisation de l'invention.Figure 3 shows a sectional view of a cathode ray tube according to a first embodiment of the invention.
La figure 4 montre par une vue en coupe un panneau pour tubes à rayons cathodiques selon un deuxième mode de réalisation de l'invention. - La figure 5 illustre un mode de réalisation d'un système de suspension d'un tube à rayons cathodiques selon le deuxième mode de réalisation de l'invention.Figure 4 shows a sectional view of a panel for cathode ray tubes according to a second embodiment of the invention. - Figure 5 illustrates an embodiment of a suspension system of a cathode ray tube according to the second embodiment of the invention.
La figure 1 représente dans une vue en coupe un tube à rayons cathodiques dans laquelle sont visibles les éléments essentiels dudit tube. Le tube comprend un panneau 8 comprenant une face avant 1 sur la surface interne de laquelle est déposée un écran formé de réseaux de matériaux luminescent, une partie arrière 6 en forme d'entonnoir, un col sensiblement cylindrique 4 à l'intérieur duquel est installé un canon à électrons 2. Le panneau peut comprendre une jupe périphérique 5 reliant la face avant à la partie arrière 6. Un masque de sélection des couleurs 10 est installé entre le canon à électrons et l'écran et est courbé de manière à ce que sa surface corresponde à la surface interne de la face avant 1.Figure 1 shows in a sectional view a cathode ray tube in which the essential elements of said tube are visible. The tube comprises a panel 8 comprising a front face 1 on the internal surface of which is deposited a screen formed of networks of luminescent materials, a rear part 6 in the form of a funnel, a substantially cylindrical neck 4 inside which is installed an electron gun 2. The panel may include a peripheral skirt 5 connecting the front face to the rear part 6. A color selection mask 10 is installed between the electron gun and the screen and is curved so that its surface corresponds to the internal surface of the front face 1.
La figure 2 illustre une méthode selon l'état de la technique pour améliorer la tenue mécanique du tube tout en diminuant l'épaisseur de verre utilisé. Pour cela, un film de polymère organique16 pouvant comportant plusieurs couches 13, 14, 15... est collé sur la face avant 12 du tube à rayons cathodiques 11. Ce film a une épaisseur comprise entre 25μm et 500μm et permet de diminuer l'épaisseur de verre d'environ 2Q% .FIG. 2 illustrates a method according to the state of the art for improving the mechanical strength of the tube while reducing the thickness of glass used. For this, an organic polymer film 16 which may have several layers 13, 14, 15 ... is bonded to the front face 12 of the tube with cathode rays 11. This film has a thickness of between 25 μm and 500 μm and makes it possible to reduce the thickness of glass by approximately 2%.
Cependant ce type de structure présente plusieurs inconvénients. Le film doit être déposé dans une salle blanche pour éviter le dépôt de poussière entre la face avant du tube et le film lui-même. Comme le film ne supporte pas les hautes températures auxquelles est amené le tube pendant ses différentes étapes de fabrication, le film est appliqué durant les phases finales de fabrication et tout défaut engendré par cette étape provoque le rejet du tube. IL en résulte un coût de fabrication plus élevé et un gain en poids de verre pour la face avant peu appréciable. La figure 3 illustre un premier mode de réalisation de l'invention.However, this type of structure has several drawbacks. The film must be deposited in a clean room to avoid the deposit of dust between the front face of the tube and the film itself. As the film does not support the high temperatures to which the tube is brought during its various stages of manufacture, the film is applied during the final stages of manufacture and any defect generated by this stage causes the rejection of the tube. This results in a higher manufacturing cost and an appreciable gain in glass weight for the front face. FIG. 3 illustrates a first embodiment of the invention.
Le tube à rayons cathodiques 20 comprend une enveloppe en verre sous vide composée d'un col sensiblement cylindrique 25, d'une partie arrière 24 évasée, en forme d'entonnoir, et d'un panneau 29 comportant une face avant 26, ledit panneau étant scellé sur sa périphérie au bord de la partie évasée . Un masque 23 est maintenu à l'intérieur du tube lorsque le tube est destiné à reproduire des images en couleurs. La face avant 26 est composée de deux parties, une partie externe sensiblement plane 21, d'épaisseur sensiblement constante et d'une partie interne 22 adhérent d'un coté à la partie externe et présente une surface interne 28 sur laquelle est déposée 1 'écran fluorescent 27. La surface interne 28 est courbée de telle manière que les courbures de ladite surface et celle du masque soient appariées de manière conventionnelle. La partie externe 21 de la face avant peut être réalisée dans un verre peu coûteux du fait qu'il puise être plan et d'épaisseur sensiblement constante. Un verre flotté, du type pour fabriquer des vitrages, peut être avantageusement utilisé.The cathode ray tube 20 comprises a vacuum glass envelope composed of a substantially cylindrical neck 25, a flared rear part 24, in the form of a funnel, and a panel 29 comprising a front face 26, said panel being sealed on its periphery at the edge of the flared portion. A mask 23 is maintained inside the tube when the tube is intended to reproduce color images. The front face 26 is composed of two parts, a substantially planar external part 21, of substantially constant thickness and an internal part 22 adhering on one side to the external part and has an internal surface 28 on which is deposited 1 ' fluorescent screen 27. The internal surface 28 is curved so that the curvatures of said surface and that of the mask are matched in a conventional manner. The external part 21 of the front face can be made of inexpensive glass because it can be flat and of substantially constant thickness. A float glass, of the type for manufacturing glazing, can advantageously be used.
La partie 22, plus complexe à réaliser peut être réalisée de la manière conventionnelle par pressage d'une goutte de verre en fusion.Part 22, which is more complex to produce, can be produced in the conventional manner by pressing a drop of molten glass.
Afin de diminuer notablement les coûts de fabrication de la face avant il faut diminuer au maximum le poids de verre de la partie interne 22 par rapport au poids de la partie externe. Cependant l'expérience montre qu'il est difficile de descendre en dessous de 20% du poids global de la face avant. En effet une face avant dont la surface externe est sensiblement plane présente des différences d'épaisseur importantes entre le centre et les bords, différences qui sont intégralement reportées sur la partie interne 22.In order to significantly reduce the manufacturing costs of the front face, the weight of the glass of the internal part 22 must be reduced as much as possible relative to the weight of the external part. However, experience shows that it is difficult to descend below 20% of the overall weight of the front face. In fact, a front face whose external surface is substantially flat has significant differences in thickness between the center and the edges, differences which are fully transferred to the internal part 22.
De manière préférentielle la partie interne représente 20% à 45% du poids du panneau 29 suivant les tailles de tube et la courbure interne de la partie interne 22 de la face avant.Preferably, the internal part represents 20% to 45% of the weight of the panel 29 depending on the tube sizes and the internal curvature of the internal part 22 of the front face.
Ce type de structure présente en outre d'autres avantages. Les faces avant des tubes actuels ont un coefficient de transmission de la lumière faible afin d'augmenter le contraste de l'image formée sur l'écran du tube. Cette demande du marché impose d'utiliser des verres sombres pour réaliser la surface de verre du panneau supportant l'écran. Cependant comme il y a une grande différence d'épaisseur, pour des tubes à surface extérieure plane, entre le centre et les bords de l'écran 27 ( pouvant aller du simple au double), la transmission du panneau est très différente entre le centre et les bords entraînant des différences de luminosités de l'image très visibles pour le spectateur. Dans le cadre de l'invention, il est possible d'utiliser une partie externe 21 en verre très sombre et d'épaisseur sensiblement constante, et une partie intérieure 22 en verre transparent pour obtenir un panneau sombre offrant le contraste désiré avec un coefficient de transmission de la lumière pratiquement uniforme sur toute la surface de l'écran. Par ailleurs il n'est plus nécessaire d'utiliser de procédés additionnels comme des films appliqués sur la surface externe de l'écran pour uniformiser la luminosité de l'image, ce qui réduit d'autant les coûts de fabrication du tube.This type of structure also has other advantages. The front faces of current tubes have a low light transmission coefficient in order to increase the contrast of the image formed on the tube screen. This market demand requires the use of dark glasses to produce the glass surface of the panel supporting the screen. However, since there is a large difference in thickness, for tubes with a flat outer surface, between the center and the edges of the screen 27 (which can range from single to double), the transmission of the panel is very different between the center and the edges resulting in differences in image brightness very visible to the viewer. In the context of the invention, it is possible to use an external part 21 made of very dark glass and of substantially constant thickness, and an internal part 22 made of transparent glass to obtain a dark panel offering the desired contrast with a coefficient of practically uniform light transmission over the entire surface of the screen. Furthermore, it is no longer necessary to use additional methods such as films applied to the external surface of the screen to standardize the brightness of the image, thereby reducing the manufacturing costs of the tube.
Dans une variante du mode de réalisation de la figure 3, la figure 4 montre une face avant 126, comprenant une couche interne en verre 22, une couche intermédiaire 21 également en verre et une couche externe 121 en matériau à base de polymère, par exemple du poly carbonate. La couche externe est solidarisée aux deux couches en verre 21 et 22 lorsque le tube est terminé jusqu'à la mise sous vide de ladite enceinte ; en effet des étapes du procédé de fabrication de ladite enceinte effectuées à haute température ne seraient pas supportables par la couche en matériau à base de polymère. L'épaisseur de la couche intermédiaire en verre sera choisie à une valeur minimale et la couche 121 à une valeur maximale pour minimiser le poids de verre total utilisé.In a variant of the embodiment of FIG. 3, FIG. 4 shows a front face 126, comprising an inner layer of glass 22, an intermediate layer 21 also of glass and an outer layer 121 of polymer-based material, for example poly carbonate. The outer layer is secured to the two glass layers 21 and 22 when the tube is finished until the vacuum of said enclosure; indeed, steps of the process for manufacturing said enclosure carried out at high temperature would not be bearable by the layer of polymer-based material. The thickness of the intermediate glass layer will be chosen to a minimum value and the layer 121 to a maximum value to minimize the total weight of glass used.
Dans un deuxième mode de réalisation de l'invention illustré par la figure 4 le panneau 39 comporte également une face avant 35 en deux parties, une partie intérieure 32 servant de support à l'écran 37 fluorescent recouverte par une partie extérieure 31. Dans ce mode de réalisation les deux parties 31 et 32 sont réalisées dans des matériaux différents :In a second embodiment of the invention illustrated in FIG. 4, the panel 39 also includes a front face 35 in two parts, an inner part 32 serving to support the fluorescent screen 37 covered by an outer part 31. In this fashion of realization the two parts 31 and 32 are made of different materials:
- un matériau inerte pour la partie intérieure par exemple du verre - un matériau plus léger et moins onéreux pour la partie extérieure 31, ce matériau pouvant être tout matériau à base de polymère organique présentant une résistance mécanique suffisante ; le poly carbonate compte tenu de sa résistance mécanique et de son faible coût peut être avantageusement choisi comme d'autres matériaux par exemple le polyuréthane ou des résines, par exemple des résines à base d'aramide.- An inert material for the inner part, for example glass - a lighter and less expensive material for the outer part 31, this material can be any material based on organic polymer having sufficient mechanical strength; poly carbonate, taking into account its mechanical strength and its low cost, can advantageously be chosen like other materials, for example polyurethane or resins, for example resins based on aramid.
Dans le mode de réalisation préférentiel illustré par la figure 4 le panneau 39 comporte une face avant 35 entourée par une jupe périphérique 38 s 'étendant sensiblement perpendiculairement à cette face avant. Le bord 34 de la jupe sert de zone de raccordement à la partie arrière du tube en forme d'entonnoir. La face avant 35 comprend une couche interne en verre 32 et une couche externe 31 en poly carbonate. La couche externe peut ou non s'étendre au moins en partie dans la zone constituant la jupe périphérique 38. En s 'étendant dans cette zone, dans laquelle l'épaisseur totale du panneau est la plus importante, il est possible de diminuer notablement la quantité de verre utilisé pour la couche interne 32 et donc le poids et le coût global du panneau.In the preferred embodiment illustrated in Figure 4 the panel 39 has a front face 35 surrounded by a peripheral skirt 38 extending substantially perpendicular to this front face. The edge 34 of the skirt serves as a connection zone to the rear part of the funnel-shaped tube. The front face 35 comprises an inner layer of glass 32 and an outer layer 31 of poly carbonate. The outer layer may or may not extend at least in part in the zone constituting the peripheral skirt 38. By extending in this zone, in which the total thickness of the panel is the greatest, it is possible to significantly reduce the amount of glass used for the inner layer 32 and therefore the weight and the overall cost of the panel.
Le tableau suivant met en relief des avantages d'un panneau réalisé selon l'invention ; pour un tube dont la surface extérieure du panneau est sensiblement plane, de diagonale d'écran égal à 68cm et de format d'écran 4 par 3, le poids global du panneau réalisé en une pièce en verre est de 21 Kg ; sel on l ' i nvention l e poi ds gl obal du panneau est di mi nué d ' envi ron 15% et l e poids du verre d ' envi ron 55%.The following table highlights the advantages of a panel produced according to the invention; for a tube whose outer surface of the panel is substantially planar, with a screen diagonal equal to 68 cm and a screen format 4 by 3, the overall weight of the panel produced in one piece of glass is 21 Kg; according to the invention the overall size of the panel is reduced by approximately 15% and the weight of the glass by approximately 55%.
Figure imgf000010_0001
Figure imgf000010_0001
Le tube est fabriqué de la façon suivante : - Le procédé de fabrication est un procédé en grande partie conventionnel dans lequel la partie arrière en forme d'entonnoir 24 est scellée à la partie en verre 32 du panneau au niveau du bord de scellement 34; après scellement du canon dans le tube, on réalise le pompage de l'air à l'intérieur de celui-ci jusqu'à atteindre un vide d'environ 1Θ"6 atmosphère. Pendant cette phase de pompage la face avant doit pouvoir résister au vide, ce qui nécessite une épaisseur minimale de verre qui ne peut être au-dessous de 40% de l'épaisseur d'un panneau avant selon 1 'état de la technique pour éviter des risques d'implosion. - La partie extérieure 31 est alors disposée sur la surface en verre de la partie 32 et est rendue solidaire à ladite partie 32 grâce à un adhésif disposé entre les deux surfaces. Cet adhésif peut être un adhésif à base de d'époxy, de si 1 icône... Cet adhésif peut contenir des agents réagissant aux rayons ultraviolets pour parfaire l'adhérence des deux parties 31 et 32.The tube is manufactured in the following way: The manufacturing method is a largely conventional method in which the rear funnel-shaped part 24 is sealed to the glass part 32 of the panel at the sealing edge 34; after sealing the barrel in the tube, the air inside it is pumped until a vacuum of about 1Θ "6 atmosphere is reached. During this pumping phase the front face must be able to withstand empty, which requires a minimum thickness of glass which cannot be below 40% of the thickness of a front panel according to the prior art to avoid risks of implosion. - The outer part 31 is then placed on the glass surface of the part 32 and is made integral with said part 32 by means of an adhesive placed between the two surfaces. This adhesive can be an epoxy-based adhesive, if 1 icon ... This adhesive can contain agents reacting to ultraviolet rays to perfect the adhesion of the two parts 31 and 32.
- La phase finale d'assemblage comprend la disposition sur la jupe du tube de la ceinture anti -implosion comprimant la partie latérale du tube.- The final assembly phase includes the provision on the skirt of the tube of the anti-implosion belt compressing the lateral part of the tube.
Dans l 'exemple de réalisation du tube de 68cm de diagonale la partie interne est d'épaisseur sensiblement constante alors que la partie externe 31 est plus épaisse dans les coins par rapport au centre de l 'écran. Cette épaisseur constante de la partie en verre est un facteur de réduction des coûts de fabrication du panneau 35.In the exemplary embodiment of the 68 cm diagonal tube, the internal part is of substantially constant thickness while the external part 31 is thicker in the corners relative to the center of the screen. This constant thickness of the glass part is a factor in reducing the manufacturing costs of the panel 35.
Alternativement à l 'exemple précédant, la partie externe 31 en matériau à base de polymère peut être d'épaisseur constante et la partie interne en verre 31 plus épaisse dans les coins du panneau.As an alternative to the preceding example, the external part 31 of polymer-based material may be of constant thickness and the internal part of glass 31 thicker in the corners of the panel.
Dans les deux cas, il sera de plus aisément possible de contrôler le coefficient de transmission de la lumière en le rendant sensiblement homogène pour toute la surface de l'écran 37 dudit panneau ; pour cela, la partie d'épaisseur constante a un coefficient plus faible ( pour améliorer le contraste de l 'image)que la partie d'épaisseur variable qui sera choisie la plus transparente possible. Ce mode de réalisation permet en outre d'inclure dans la partie extérieure base de matériaux polymères 31, les oreilles métalliques 40 de fixation du tube à l'intérieur du boîtier du récepteur de télévision, ce qui évite l'étape de soudure desdites oreilles sur la surface de la bande anti -implosion, généralement effectuée prés des coins de ladite ceinture. Les modes de réalisation décrits ci -dessus ne sont pas limitatifs ; le panneau 35 peut être composé de plus de 2 couches de matériaux solidarisées les unes aux autres. Il peut par exemple être composé de deux couches en verre chacune des deux couches représentant au moins 20% du poids total du panneau, sandwi chant une couche en matériau à base de polymère. Dans un autre mode de réalisation le panneau est composé de deux couches représentant au moins 20% du poids total du panneau, une en verre et une en matériau à base de polymère, la couche externe étant recouverte par un film en matériau polymère destiné à contrôler la transmission du panneau ou diminuer la réflexion de la lumière sur la surface dudit panneau. In both cases, it will be more easily possible to control the light transmission coefficient by making it substantially homogeneous for the entire surface of the screen 37 of said panel; for this, the part of constant thickness has a lower coefficient (to improve the contrast of the image) than the part of variable thickness which will be chosen as transparent as possible. This embodiment also makes it possible to include in the outer part, base of polymer materials 31, the metal ears 40 for fixing the tube to inside the housing of the television receiver, which avoids the step of welding said ears to the surface of the anti-implosion strip, generally carried out near the corners of said belt. The embodiments described above are not limiting; the panel 35 can be composed of more than 2 layers of materials secured to each other. It can for example be composed of two glass layers each of the two layers representing at least 20% of the total weight of the panel, sandwi sing a layer of polymer-based material. In another embodiment, the panel is composed of two layers representing at least 20% of the total weight of the panel, one in glass and one in polymer-based material, the outer layer being covered by a film of polymeric material intended to control the transmission of the panel or reduce the reflection of light on the surface of said panel.

Claims

REVENDICATIONS
1/ Tube à rayons cathodiques comprenant une enceinte sous vide formée par un panneau (29,39) comportant une face avant (26,35, 126)servant de support à un écran luminescent ( 27,37), et par une partie arrière en forme d'entonnoi r (24) , caractérisé en ce que ladite face avant est composée d'au moins deux couches (21,22,121 ;31,32) de matériaux, chacune des au moins deux desdites couches représentant au moins 20% du poids total du panneau.1 / Cathode ray tube comprising a vacuum enclosure formed by a panel (29,39) comprising a front face (26,35, 126) serving as support for a luminescent screen (27,37), and by a rear part in funnel shape r (24), characterized in that said front face is composed of at least two layers (21,22,121; 31,32) of materials, each of at least two of said layers representing at least 20% by weight total of the panel.
2/Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que les deux couches sont en verre.2 / cathode ray tube according to claim 1 characterized in that the two layers are glass.
3/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce qu'une des deux couches est faite d'un matériau à base de polymère organique.3 / cathode ray tube according to claim 1 characterized in that one of the two layers is made of a material based on organic polymer.
4/ Tube à rayons cathodiques selon la revendication précédente caractérisé en ce que le matériau polymère est du polycarbonate.4 / cathode ray tube according to the preceding claim characterized in that the polymeric material is polycarbonate.
5/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce qu'au moins une des deux couches de la face avant est d'épaisseur sensiblement uniforme. 6/ Tube à rayons cathodiques selon la revendication 2 caractérisé en ce que la couche la plus externe est d'épaisseur sensiblement uniforme.5 / cathode ray tube according to claim 1 characterized in that at least one of the two layers of the front face is of substantially uniform thickness. 6 / cathode ray tube according to claim 2 characterized in that the outermost layer is of substantially uniform thickness.
7/ Tube à rayons cathodiques selon la revendication 3 caractérisé en ce que la couche interne est en verre et d'épaisseur sensiblement uniforme7 / cathode ray tube according to claim 3 characterized in that the inner layer is glass and of substantially uniform thickness
8/ Tube à rayons cathodiques selon la revendication 3 caractérisé en ce que le panneau comporte en outre une jupe périphérique sensiblement perpendiculaire à la face avant et en ce que la couche de matériau à base de polymère s'étend également au moins en partie au-dessus de la jupe périphérique.8 / cathode ray tube according to claim 3 characterized in that the panel further comprises a peripheral skirt substantially perpendicular to the front face and in that the layer of polymer-based material also extends at least partially au- above the peripheral skirt.
9/ Tube à rayons cathodiques selon la revendication précédente caractérisé en ce que des oreilles de suspension du tube sont incluses dans le matériau à base de polymère.9 / cathode ray tube according to the preceding claim characterized in that the tube suspension ears are included in the polymer-based material.
10/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que les coefficients de transmission de la lumière des deux couches sont différents .10 / cathode ray tube according to claim 1 characterized in that the light transmission coefficients of the two layers are different.
11/ Tube à rayons cathodiques selon la revendication 1 caractérisé en ce que lesdites au moins deux couches sont composées d'une couche d'épaisseur sensiblement constante et d'une couche d'épaisseur variable, la couche d'épaisseur variable ayant un coefficient de transmission de la lumière supérieur à celui de la couche d'épaisseur sensiblement constante. 11 / cathode ray tube according to claim 1 characterized in that said at least two layers are composed of a layer of substantially constant thickness and a layer of variable thickness, the layer of variable thickness having a coefficient of light transmission greater than that of the layer of substantially constant thickness.
PCT/FR2004/050164 2003-04-29 2004-04-21 Front face for a cathode ray tube WO2004097887A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4884006A (en) * 1986-12-30 1989-11-28 Zenith Electronics Corporation Inner surface specular reflection suppression in flat CRT faceplate
US6407493B1 (en) * 1999-08-25 2002-06-18 Asahi Glass Company, Limited Vacuum envelope for a display device
WO2002089172A1 (en) * 2001-04-26 2002-11-07 Sony Corporation Cathode-ray tube

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4884006A (en) * 1986-12-30 1989-11-28 Zenith Electronics Corporation Inner surface specular reflection suppression in flat CRT faceplate
US6407493B1 (en) * 1999-08-25 2002-06-18 Asahi Glass Company, Limited Vacuum envelope for a display device
WO2002089172A1 (en) * 2001-04-26 2002-11-07 Sony Corporation Cathode-ray tube

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