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WO2025087990A1 - Process for manufacturing a display device - Google Patents

Process for manufacturing a display device Download PDF

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Publication number
WO2025087990A1
WO2025087990A1 PCT/EP2024/079985 EP2024079985W WO2025087990A1 WO 2025087990 A1 WO2025087990 A1 WO 2025087990A1 EP 2024079985 W EP2024079985 W EP 2024079985W WO 2025087990 A1 WO2025087990 A1 WO 2025087990A1
Authority
WO
WIPO (PCT)
Prior art keywords
cover plate
display structure
holding member
curved shape
display
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.)
Pending
Application number
PCT/EP2024/079985
Other languages
French (fr)
Inventor
Djamel Lekmine
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.)
Valeo Comfort and Driving Assistance SAS
Original Assignee
Valeo Comfort and Driving Assistance 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 Valeo Comfort and Driving Assistance SAS filed Critical Valeo Comfort and Driving Assistance SAS
Publication of WO2025087990A1 publication Critical patent/WO2025087990A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133305—Flexible substrates, e.g. plastics, organic film
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/1303—Apparatus specially adapted to the manufacture of LCDs
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133308—Support structures for LCD panels, e.g. frames or bezels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/18—Handling of layers or the laminate
    • B32B38/1866—Handling of layers or the laminate conforming the layers or laminate to a convex or concave profile

Definitions

  • the present invention relates in particular to a method of manufacturing a display device, in particular intended to be installed on board a vehicle.
  • the vehicle can be land, sea or air.
  • the invention aims in particular to overcome this problem.
  • the invention thus relates to a method of manufacturing a display device, the method comprising the following steps:
  • this cover plate being in particular made of glass or transparent PC, the curvature of this cover plate being in particular obtained beforehand by thermoforming;
  • the cover plate is first shaped into a curve, preferably by thermoforming, with the addition of heat.
  • the cover plate and the holding member are initially curved in shape while the display structure is initially generally flat.
  • the display structure is thus shaped by undergoing cold pressure, by being sandwiched between the cover plate and the holding member.
  • cover plate is formed into a curved shape by hot thermoforming, the shape of the cover plate is stable.
  • the display structure undergoes cold forming with the consequence that the display structure is not stable.
  • the display structure undergoes internal stresses due to the curvature that the display structure takes.
  • the display structure is not hot formed because this would require a complex and expensive process.
  • the invention makes it possible to preserve the balance of constraints within the display structure, which makes it possible to eliminate or reduce the Mura effect.
  • the deformation of the display structure is carried out using a press tool configured to press on the stack which rests on a press base.
  • this deformation is carried out cold, without the addition of heat.
  • the press tool has a bearing surface with a shape which matches the curved shape of the cover plate.
  • an optically clear adhesive is deposited between the display structure and the cover plate.
  • the optically transparent adhesive is deposited between the display structure and the holding member.
  • the display structure comprises a base substrate, in particular made of glass, which carries active layers, in particular with electrodes and liquid crystals interacting with the electrodes to enable the display.
  • the display structure is in particular of the TFT type [22]
  • the cover plate is a plate of optically transparent material, made of a material capable of being hot formed.
  • the display structure comprises, in addition to the base substrate, in particular made of glass, an upper plate, in particular made of glass, which is intended to come opposite the cover plate.
  • the display structure can have a multi-layer structure, with, on one side, the base substrate and, on the other side, the upper plate, in particular made of glass.
  • the upper plate of the display structure is glued to the cover plate which is stable in terms of its shape while the base substrate, in the absence of a holding member according to the invention, would be subject to stresses resulting in it becoming detached from the upper plate.
  • the holding member according to the invention the base substrate of the display structure remains held with the curved shape.
  • the holding member is presented as an additional part which is an integral part of the display device and is not a part used only at the time of manufacture.
  • the holding member has a main face intended to come opposite the display structure.
  • the main face of the holding member has a curved shape.
  • the holding member comprises an edge which serves to stiffen the holding member.
  • the stiffening edge extends around the entire periphery of the main face of the holding member. [33] According to one aspect of the invention, the stiffening edge extends away from the display structure.
  • the stiffening edge is made in one piece with the main face of the holding member.
  • the main face of the holding member is optically transparent.
  • the main face of the holding member is perforated.
  • the openwork holding member runs along a peripheral strip of the display structure, and forms a frame.
  • the frame formed by the holding member may be sufficient to keep the display structure stable against internal stresses caused by curvature.
  • the holding member may be made of a transparent or translucent material, in particular glass or transparent PC (polycarbonate).
  • the holding member may be made entirely of optically transparent material.
  • the holding member may form a holding plate which is in particular similar to the cover plate, being in particular transparent.
  • the holding plate and the cover plate may have similar shapes, in particular identical surface areas.
  • the thickness of the holding plate can be variable.
  • the variation in thickness can be chosen as a function of the radius of curvature taken by the holding plate.
  • the thickness of the holding plate and the thickness of the cover plate may be identical.
  • the display device thus comprises a holding plate and a cover plate between which the display structure which has taken a curved shape is fixed.
  • the holding plate like the cover plate, has a curved shape obtained beforehand by hot forming.
  • this stiffening edge can be made of optically opaque material while the main face is made of optically transparent material.
  • the holding member is configured to encapsulate elements of a backlight unit.
  • the backlight module comprises a housing in which are placed a support for light sources, in particular of the LED type, a light guide above the support for light sources, and above this light guide, a stack of optical sheets.
  • the holding member is configured to close the housing of the backlight unit.
  • the display device is placed on the housing of the backlight unit.
  • the holding member of the lighting device closes this housing of the backlighting unit.
  • the holding member of the lighting device thus serves as a housing cover for the module of the backlighting unit, preferably being made of optically transparent or translucent material.
  • the invention also relates to a display device obtained by the above method.
  • the invention also relates to a display device comprising successively, in a stack:
  • this cover plate being in particular made of glass or transparent PC;
  • this display structure being in particular of the TFT type, the curved shape of the display structure resulting from cold forming;
  • a holding member having a curved shape substantially matching that of the cover plate, and configured to hold the display structure with the curved shape obtained from cold forming.
  • the cover plate is curved at least in a peripheral area of the cover plate, namely an area which is adjacent to the periphery of the cover plate.
  • the cover plate is curved over its entire surface area.
  • the cover plate does not include any flat plot.
  • FIG. 5 illustrates, schematically and partially, in section, a member for holding a display device according to an exemplary embodiment of the invention.
  • Figure 1 shows steps of a method for manufacturing a display device 1 according to an exemplary embodiment of the invention, comprising the following steps:
  • this cover plate 10 being made of glass or transparent PC, the curvature of this cover plate being obtained beforehand by thermoforming;
  • this display structure being of the TFT type (for “Thin-film transistor” in English or Thin-film transistor);
  • step 1A placing the generally flat display structure 20 between the cover plate 10 and the holding member 30
  • step 1 B applying pressure to the stack 50 thus formed, to deform the display structure 20 so that it matches the shape of the cover plate 10 and the holding member 30, the application of the pressure being carried out cold (step 1 B);
  • the cover plate 10 is first shaped into a curved form, by thermoforming, with the addition of heat.
  • the cover plate 10 and the holding member 30 are initially curved in shape while the display structure 20 is initially generally flat.
  • the shaping of the display structure 20 is thus done by undergoing cold pressure, by being sandwiched between the cover plate 10 and the holding member 30.
  • cover plate 10 Since the cover plate 10 is formed into a curved shape by hot thermoforming, the shape of the cover plate 10 is stable.
  • the display structure 20 undergoes cold forming with the consequence that the display structure 20 is not stable.
  • the display structure 20 undergoes internal stresses due to the curvature that the display structure takes.
  • the display structure 20 is not hot formed because this would require a complex and expensive process.
  • Mura effect manifests itself in particular by defects in homogeneity in the display structure of the TFT screen type.
  • Some of the layers of the display structure tend to return to the planar shape after the pressure that served to produce the deformation is released.
  • the invention makes it possible to preserve the balance of constraints within the display structure 20, which makes it possible to eliminate or reduce the Mura effect.
  • the deformation of the display structure 20 is carried out using a press tool 60 configured to press on the stack which rests on a press base 61.
  • the press tool 60 has a bearing surface with a shape which matches the curved shape of the cover plate 10.
  • a layer of optically transparent adhesive 25 (in English “Optical Clear Adhesive” or OCA) is deposited between the display structure 20 and the cover plate 10.
  • Another layer of optically transparent glue 25 is deposited between the display structure 20 and the holding member 30.
  • the cover plate 10 is a plate of optically transparent material, made of a material capable of being hot formed.
  • the display structure 20 comprises a base substrate 22, made of glass, which carries active layers, with electrodes and liquid crystals interacting with the electrodes to enable the display.
  • the display structure 20 comprises, in addition to the base substrate 22, an upper plate 24, made of glass, which is intended to come opposite the cover plate 10, as illustrated in FIG. 2.
  • the display structure 20 can have a multi-layer structure, with, on one side, the base substrate 22 and, on the other side, the upper plate 24.
  • the holding member 30 is presented as an additional part which is an integral part of the display device 1 and is not a part used only at the time of manufacture.
  • the holding member 30 has a main face 31 intended to come opposite the display structure 20.
  • the main face 31 of the holding member 30 has a curved shape.
  • the holding member 30 comprises an edge 32 which serves to stiffen the holding member 30.
  • the stiffening edge 32 extends around the entire periphery of the main face of the holding member 30, where the internal stresses of the display structure 20 can be the most damaging.
  • the stiffening edge 32 extends away from the display structure 20.
  • the stiffening edge 32 is made in one piece with the main face 31 of the holding member 30.
  • the main face 31 of the holding member 30 is solid. This means that this main face is not perforated.
  • the main face 31 of the holding member 30 is optically transparent, and the stiffening edge 32 may be optically opaque, as illustrated in FIG. 5.
  • the main face 31 of the holding member 30 is perforated.
  • the openwork holding member 30 runs along a peripheral strip of the display structure 20, and forms a frame.
  • the frame formed by the holding member 30 may be sufficient to keep the display structure stable against internal stresses caused by curvature.
  • the holding member 30 may be made of a transparent or translucent material, in particular glass or transparent PVC.
  • the holding member 30 may be made entirely of optically transparent material.
  • the holding member 30 can be produced by injection molding.
  • the holding member 30 may form a holding plate 35 which is similar, or even identical, to the cover plate 10, being transparent.
  • the holding plate and the cover plate 10 may have similar shapes, in particular identical surface areas.
  • the thickness of the holding plate 35 can be variable. [107] The variation in thickness can be chosen as a function of the radius of curvature taken by the holding plate 35.
  • the thickness of the holding plate 35 and the thickness of the cover plate 10 may be the same.
  • the display device thus comprises a holding plate 35 and a cover plate 10 between which the display structure 20 is fixed, which has taken a curved shape.
  • the holding plate 35 like the cover plate 10, has a curved shape obtained beforehand by hot forming.
  • the holding member 30 is configured to encapsulate elements of a backlight unit 70.
  • the backlight module 70 comprises a housing 71 in which are placed an electronic card 72 with LED type light sources 73, a light guide 74 above the electronic card 72, and above this light guide, a stack of optical sheets 75.
  • the holding member 30 is configured to close the housing 71 of the backlight unit 70.
  • the display device 1 is placed on the housing 71 of the backlight unit.
  • the holding member 30 of the lighting device closes this housing 71 of the backlighting unit 70.
  • the holding member 30 of the lighting device thus serves as a housing cover 71 of the module of the backlighting unit, being made of optically transparent or translucent material.
  • the invention makes it possible to obtain a display device comprising successively, in a stack: a cover plate 10 of curved shape, this cover plate 10 being in particular based on glass or based on transparent PC; - a display structure 20 of curved shape, this display structure 20 being in particular of the TFT type, the curved shape of the display structure 20 resulting from cold forming;
  • a holding member 30 having a curved shape substantially matching that of the cover plate 10, and configured to hold the display structure 20 with the curved shape obtained from cold forming.
  • the cover plate 10 is curved at least in a peripheral area of the cover plate 10, namely an area which is adjacent to the periphery of the cover plate 10.
  • the cover plate 10 is preferably curved over its entire surface area.
  • the cover plate 10 does not include any flat plot.
  • the curvature of the cover plate 10 can be chosen according to the needs, in particular the shape.
  • the holding member can be made by injection molding one material or two materials in a single mold. In the case of two materials, the molding operation is referred to as 2K molding. The materials can be different.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

The invention relates to a process for manufacturing a display device (1), the process comprising the following steps: - providing a cover plate (10) of curved shape, this cover plate (10) being in particular made of glass or made of transparent PC, the curvature of this cover plate (10) being in particular obtained beforehand by thermoforming; - providing a generally flat display structure (20), this display structure (20) being in particular of the TFT type; - providing a retaining member (30) having a curved shape which substantially matches that of the cover plate (10); - placing the generally flat display structure (20) between the cover plate (10) and the retaining member (30); - applying a pressure to the stack thus formed, in order to deform the display structure (20) such that it matches the shape of the cover plate (10) and of the retaining member (30), the pressure being applied in particular under cold conditions; - removing the stack, leaving the retaining member (30) attached to the display structure (20) permanently.

Description

Description Description

Titre de l'invention : Procédé de fabrication d’un dispositif d’affichage Title of the invention: Method of manufacturing a display device

[1] La présente invention concerne notamment un procédé de fabrication d’un dispositif d’affichage, notamment destiné à être embarqué à bord d’un véhicule. [1] The present invention relates in particular to a method of manufacturing a display device, in particular intended to be installed on board a vehicle.

[2] Le véhicule peut être de type terrestre, maritime ou aérien. [2] The vehicle can be land, sea or air.

[3] Actuellement, les dispositifs d’affichage, notamment de type TFT, utilise une lentille/verre de protection courbée, recouvrant la structure TFT. Lorsque le rayon de courbure devient inférieur à une certaine limite, les cristaux liquides de l'écran TFT sont soumis à une contrainte en raison de la traction exercée par le verre de l'écran qui n'est pas stable en termes de courbure. Cela induit ce que l'on appelle l'effet Mura, comme expliqué plus bas. [3] Currently, display devices, especially TFT type, use a curved protective lens/glass, covering the TFT structure. When the curvature radius becomes less than a certain limit, the liquid crystals of the TFT screen are subjected to stress due to the traction exerted by the screen glass which is not stable in terms of curvature. This induces what is called the Mura effect, as explained below.

[4] L’invention vise notamment à pallier ce problème. [4] The invention aims in particular to overcome this problem.

[5] L’invention a ainsi pour objet un procédé de fabrication d’un dispositif d’affichage, le procédé comportant les étapes suivantes : [5] The invention thus relates to a method of manufacturing a display device, the method comprising the following steps:

- fournir une plaque de couverture de forme courbe, cette plaque de couverture étant notamment à base de verre ou à base de PC transparent, la courbure de cette plaque de couverture étant notamment obtenue au préalable par thermoformage ; - provide a curved cover plate, this cover plate being in particular made of glass or transparent PC, the curvature of this cover plate being in particular obtained beforehand by thermoforming;

- fournir une structure d’affichage globalement plane, cette structure d’affichage étant notamment de type TFT ; - provide a generally flat display structure, this display structure being in particular of the TFT type;

- fournir un organe de maintien présentant une forme courbe épousant sensiblement celle de la plaque de couverture ; - provide a holding member having a curved shape substantially matching that of the cover plate;

- placer la structure d’affichage globalement plane entre la plaque de couverture et l’organe de maintien ; - appliquer une pression sur l’empilement ainsi formé, pour déformer la structure d’affichage de sorte qu’elle épouse la forme de la plaque de couverture et de l’organe de maintien, l’application de la pression étant notamment réalisée à froid; - place the generally flat display structure between the cover plate and the holding member; - applying pressure to the stack thus formed, to deform the display structure so that it matches the shape of the cover plate and the holding member, the application of the pressure being carried out in particular cold;

- retirer l’empilement en laissant à demeure l’organe de maintien fixé à la structure d’affichage. - remove the stack, leaving the retaining member attached to the display structure.

[6] Selon l’un des aspects de l’invention, la plaque de couverture est préalablement mise sous forme courbe, de préférence par thermoformage, avec apport de chaleur. [6] According to one aspect of the invention, the cover plate is first shaped into a curve, preferably by thermoforming, with the addition of heat.

[7] Ainsi, dans l’invention, la plaque de couverture et l’organe de maintien sont initialement de forme courbe tandis que structure d’affichage est initialement globalement plane. La mise en forme de la structure d’affichage se fait ainsi en subissant une pression à froid, en étant prise en sandwich entre la plaque de couverture et l’organe de maintien. [7] Thus, in the invention, the cover plate and the holding member are initially curved in shape while the display structure is initially generally flat. The display structure is thus shaped by undergoing cold pressure, by being sandwiched between the cover plate and the holding member.

[8] Comme la plaque de couverture est mise sous forme courbe par thermoformage à chaud, la forme de la plaque de couverture est stable. [8] Since the cover plate is formed into a curved shape by hot thermoforming, the shape of the cover plate is stable.

[9] Au contraire, la structure d'affichage subit un formage à froid avec comme conséquence, que la structure d'affichage n'est pas stable. Ainsi, la structure d'affichage subit des contraintes internes du fait de la courbure que prend la structure d'affichage. La structure d'affichage n'est pas formée à chaud car cela nécessiterait un procédé complexe et coûteux. [9] On the contrary, the display structure undergoes cold forming with the consequence that the display structure is not stable. Thus, the display structure undergoes internal stresses due to the curvature that the display structure takes. The display structure is not hot formed because this would require a complex and expensive process.

[10] En l'absence de l'organe de maintien, les contraintes internes peuvent avoir un impact sur des couches qui composent la structure d’affichage. Dans le cas où la structure d'affichage est de type TFT avec différentes couches dont une couche de cristaux liquides, certaines de ces couches peuvent, sous l'effet de contraintes internes dues à la courbure, se décoller l’une de l’autre, ce qui génère des zones de non-uniformité au sein de la structure d'affichage accompagnées d’effet Mura indésirable. [10] In the absence of the holding member, internal stresses can have an impact on layers that make up the display structure. In the case where the display structure is of the TFT type with different layers including a liquid crystal layer, some of these layers can, under the effect of internal stresses due to the curvature, detach from each other, which generates areas of non-uniformity within the display structure accompanied by an undesirable Mura effect.

[11] On rappelle que l'effet Mura se manifeste notamment par des défauts d’homogénéité dans la structure d'affichage de type écran TFT. [12] Il a été constaté, de manière surprenante, que grâce à l'organe de maintien, il est possible de supprimer ou réduire l'effet Mura. [11] It should be remembered that the Mura effect manifests itself in particular through homogeneity defects in the TFT screen type display structure. [12] It has been found, surprisingly, that thanks to the holding organ, it is possible to eliminate or reduce the Mura effect.

[13] Il a été constaté que, grâce à l'invention la présence de l'organe de maintien, il est possible d'équilibrer la force exercée par la plaque de couverture sur la structure d'affichage. Ce déséquilibre de contraintes sur la structure d’affichage provient du fait que la plaque de couverture a été déformée de manière stable (à chaud) alors que la structure d'affichage a été déformée à froid. Certaines des couches de la structure d'affichage ont tendance à reprendre à la forme plane après relâchement de la pression qui a servi à produire la déformation. [13] It has been found that, thanks to the invention and the presence of the holding member, it is possible to balance the force exerted by the cover plate on the display structure. This imbalance of stresses on the display structure comes from the fact that the cover plate has been deformed in a stable manner (when hot) while the display structure has been deformed when cold. Some of the layers of the display structure tend to return to the flat shape after releasing the pressure which was used to produce the deformation.

[14] En résumé, il a été constaté que l'invention permet de préserver l'équilibre des contraintes au sein de la structure d'affichage, ce qui permet de supprimer ou réduire l'effet Mura. [14] In summary, it has been found that the invention makes it possible to preserve the balance of constraints within the display structure, which makes it possible to eliminate or reduce the Mura effect.

[15] Selon l’un des aspects de l’invention, la déformation de la structure d'affichage est réalisée à l'aide d'un outil de presse configuré pour presser sur l'empilement qui repose sur un socle de presse. [15] According to one aspect of the invention, the deformation of the display structure is carried out using a press tool configured to press on the stack which rests on a press base.

[16] Selon l’un des aspects de l’invention, cette déformation est réalisée à froid, sans apport de chaleur. [16] According to one aspect of the invention, this deformation is carried out cold, without the addition of heat.

[17] Selon l’un des aspects de l’invention, l'outil de presse présente une surface d'appui avec une forme qui épouse la forme courbe de la plaque de couverture. [17] According to one aspect of the invention, the press tool has a bearing surface with a shape which matches the curved shape of the cover plate.

[18] Selon l’un des aspects de l’invention, une colle optiquement transparente (OCA) est déposée entre la structure d'affichage et la plaque de couverture. [18] According to one aspect of the invention, an optically clear adhesive (OCA) is deposited between the display structure and the cover plate.

[19] Selon l’un des aspects de l’invention, la colle optiquement transparente (OCA) est déposée entre la structure d'affichage et l'organe de maintien. [19] According to one aspect of the invention, the optically transparent adhesive (OCA) is deposited between the display structure and the holding member.

[20] Selon l’un des aspects de l’invention, la structure d'affichage comporte un substrat de base, notamment en verre, qui porte des couches actives, notamment avec des électrodes et des cristaux liquides en interaction avec les électrodes pour permettre l'affichage. [20] According to one aspect of the invention, the display structure comprises a base substrate, in particular made of glass, which carries active layers, in particular with electrodes and liquid crystals interacting with the electrodes to enable the display.

[21] Selon l’un des aspects de l’invention, la structure d'affichage est notamment de type de TFT [22] Selon l’un des aspects de l’invention, la plaque de couverture est une plaque en matière optiquement transparente, réalisée dans un matériau capable d'être formé à chaud. [21] According to one aspect of the invention, the display structure is in particular of the TFT type [22] According to one aspect of the invention, the cover plate is a plate of optically transparent material, made of a material capable of being hot formed.

[23] Selon l’un des aspects de l’invention, la structure d'affichage comporte, outre le substrat de base notamment en verre, une plaque supérieure, notamment en verre, qui est destinée à venir en regard de la plaque de couverture. [23] According to one aspect of the invention, the display structure comprises, in addition to the base substrate, in particular made of glass, an upper plate, in particular made of glass, which is intended to come opposite the cover plate.

[24] Ainsi la structure d'affichage peut présenter une structure multicouche, avec, sur un côté, le substrat de base et, de l'autre côté, la plaque supérieure, notamment en verre. [24] Thus the display structure can have a multi-layer structure, with, on one side, the base substrate and, on the other side, the upper plate, in particular made of glass.

[25] Quand plus haut dans la description, il est mentionné des contraintes internes au sein de la structure d'affichage, on peut dire que ce sont le substrat de base et la plaque supérieure de la structure d'affichage qui ont tendance être décollés l'un de l'autre sur les bords du fait de ces contraintes internes. [25] When internal stresses within the display structure are mentioned earlier in the description, it can be said that it is the base substrate and the top plate of the display structure which tend to be detached from each other at the edges due to these internal stresses.

[26] En effet, la plaque supérieure de la structure d'affichage se trouve collée à la plaque de couverture qui est stable quant à sa forme tandis que le substrat de base, en l’absence d’un organe de maintien selon l’invention, subirait des contraintes ayant pour conséquence de le décoller de la plaque supérieure. [26] In fact, the upper plate of the display structure is glued to the cover plate which is stable in terms of its shape while the base substrate, in the absence of a holding member according to the invention, would be subject to stresses resulting in it becoming detached from the upper plate.

[27] Grâce à l'organe de maintien selon l’invention, le substrat de base de la structure d'affichage reste maintenu avec la forme courbe. [27] Thanks to the holding member according to the invention, the base substrate of the display structure remains held with the curved shape.

[28] Selon l’un des aspects de l’invention, l'organe de maintien se présente comme une pièce additionnelle qui fait partie intégrante du dispositif d'affichage et n’est pas une pièce servant uniquement au moment de la fabrication. [28] According to one aspect of the invention, the holding member is presented as an additional part which is an integral part of the display device and is not a part used only at the time of manufacture.

[29] Selon l’un des aspects de l’invention, l'organe de maintien présente une face principale destinée à venir en vis-à-vis de la structure d'affichage. [29] According to one aspect of the invention, the holding member has a main face intended to come opposite the display structure.

[30] Selon l’un des aspects de l’invention, la face principale de l'organe de maintien présente une forme courbe. [30] According to one aspect of the invention, the main face of the holding member has a curved shape.

[31] Selon l’un des aspects de l’invention, l’organe de maintien comporte un bord qui sert de rigidification à l’organe de maintien. [31] According to one aspect of the invention, the holding member comprises an edge which serves to stiffen the holding member.

[32] Selon l’un des aspects de l’invention, le bord de rigidification s’étend sur tout le pourtour de la face principale de l'organe de maintien. [33] Selon l’un des aspects de l’invention, le bord de rigidification s’étend à l’opposé de la structure d'affichage. [32] According to one aspect of the invention, the stiffening edge extends around the entire periphery of the main face of the holding member. [33] According to one aspect of the invention, the stiffening edge extends away from the display structure.

[34] Selon l’un des aspects de l’invention, le bord de rigidification est réalisé d'un seul tenant avec la face principale de l'organe de maintien. [34] According to one aspect of the invention, the stiffening edge is made in one piece with the main face of the holding member.

[35] Selon l’un des aspects de l’invention, la face principale de l'organe de maintien est pleine. Ceci signifie que cette face principale n’est pas ajourée. [35] According to one aspect of the invention, the main face of the holding member is solid. This means that this main face is not perforated.

[36] Dans ce cas, la face principale de l'organe de maintien est optiquement transparente. [36] In this case, the main face of the holding member is optically transparent.

[37] En variante, la face principale de l'organe de maintien est ajourée. [37] Alternatively, the main face of the holding member is perforated.

[38] Par exemple, l’organe de maintien ajouré longe une bande de pourtour de la structure d’affichage, et forme un cadre. [38] For example, the openwork holding member runs along a peripheral strip of the display structure, and forms a frame.

[39] Selon l’un des aspects de l’invention, le cadre formé par l'organe de maintien peut être suffisant pour maintenir la structure d'affichage stable vis-à-vis des contraintes internes provoquées par la courbure. [39] According to one aspect of the invention, the frame formed by the holding member may be sufficient to keep the display structure stable against internal stresses caused by curvature.

[40] Selon l’un des aspects de l’invention, l'organe de maintien peut être réalisé dans un matériau transparent ou translucide, notamment en verre ou en PC (polycarbonate) transparent. [40] According to one aspect of the invention, the holding member may be made of a transparent or translucent material, in particular glass or transparent PC (polycarbonate).

[41] Selon l’un des aspects de l’invention, l'organe de maintien peut être entièrement réalisée en matériau transparent optiquement. [41] According to one aspect of the invention, the holding member may be made entirely of optically transparent material.

[42] Selon l’un des aspects de l’invention, l'organe de maintien peut être réalisé par moulage par injection. [42] According to one aspect of the invention, the holding member can be produced by injection molding.

[43] Selon l’un des aspects de l’invention, l'organe de maintien peut former une plaque de maintien qui est notamment similaire à la plaque de couverture, étant notamment transparent. [43] According to one aspect of the invention, the holding member may form a holding plate which is in particular similar to the cover plate, being in particular transparent.

[44] Selon l’un des aspects de l’invention, la plaque de maintien et la plaque de couverture peuvent présenter des formes similaires, notamment des superficies identiques. [44] According to one aspect of the invention, the holding plate and the cover plate may have similar shapes, in particular identical surface areas.

[45] Selon l’un des aspects de l’invention, l'épaisseur de la plaque de maintien peut être variable. [46] Selon l’un des aspects de l’invention, la variation de l'épaisseur peut être choisie en fonction du rayon de courbure que prend la plaque de maintien. [45] According to one aspect of the invention, the thickness of the holding plate can be variable. [46] According to one aspect of the invention, the variation in thickness can be chosen as a function of the radius of curvature taken by the holding plate.

[47] Selon l’un des aspects de l’invention, l’épaisseur de la plaque de maintien et l'épaisseur de la plaque de couverture peuvent être identiques. [47] According to one aspect of the invention, the thickness of the holding plate and the thickness of the cover plate may be identical.

[48] Ainsi il est possible de répartir l'épaisseur de la plaque de maintien et celle de la plaque de couverture de part et d'autre de la structure d'affichage. [48] It is thus possible to distribute the thickness of the holding plate and that of the cover plate on either side of the display structure.

[49] Selon l’un des aspects de l’invention, le dispositif d'affichage comporte ainsi une plaque de maintien et une plaque de couverture entre lesquelles est fixée la structure d'affichage qui a pris une forme courbe. [49] According to one aspect of the invention, the display device thus comprises a holding plate and a cover plate between which the display structure which has taken a curved shape is fixed.

[50] Selon l’un des aspects de l’invention, la plaque de maintien, tout comme la plaque de couverture, présentent une forme courbe obtenue préalablement par formage à chaud. [50] According to one aspect of the invention, the holding plate, like the cover plate, has a curved shape obtained beforehand by hot forming.

[51 ] La présence de la plaque de maintien en plus de la plaque de couverture permet notamment d'améliorer la conformité concernant l’absorption d'énergie en cas d'impact. [51] The presence of the retaining plate in addition to the cover plate makes it possible in particular to improve compliance with regard to energy absorption in the event of impact.

[52] Dans le cas où l'organe de maintien présente un bord de rigidification, ce bord de rigidification peut être réalise en matière optiquement opaque tandis que la face principale est réalisée en matière optiquement transparente. [52] In the case where the holding member has a stiffening edge, this stiffening edge can be made of optically opaque material while the main face is made of optically transparent material.

[53] Selon l'un des aspects de l'invention, l'organe de maintien est configuré pour encapsuler des éléments d'une unité de rétroéclairage. [53] According to one aspect of the invention, the holding member is configured to encapsulate elements of a backlight unit.

[54] Selon l’un des aspects de l’invention, le module de rétroéclairage comporte un boîtier dans lequel sont placés un support de sources de lumière notamment de type LED, un guide de lumière au-dessus du support de sources de lumière, et au-dessus de ce guide lumière, un empilement de feuilles optiques. [54] According to one aspect of the invention, the backlight module comprises a housing in which are placed a support for light sources, in particular of the LED type, a light guide above the support for light sources, and above this light guide, a stack of optical sheets.

[55] Selon l’un des aspects de l’invention, l'organe de maintien est configuré pour fermer le boîtier de l'unité de rétroéclairage. [55] According to one aspect of the invention, the holding member is configured to close the housing of the backlight unit.

[56] Selon l’un des aspects de l’invention, le dispositif d'affichage est posé sur le boîtier de l'unité de rétroéclairage. [56] According to one aspect of the invention, the display device is placed on the housing of the backlight unit.

[57] Selon l’un des aspects de l’invention, l'organe de maintien du dispositif d'éclairage vient fermer ce boîtier de l'unité de rétroéclairage. [58] Selon l’un des aspects de l’invention, l'organe de maintien du dispositif d'éclairage sert ainsi de couvercle boîtier du module de l'unité de rétroéclairage, étant de préférence réalisé en matière optiquement transparente ou translucide. [57] According to one aspect of the invention, the holding member of the lighting device closes this housing of the backlighting unit. [58] According to one aspect of the invention, the holding member of the lighting device thus serves as a housing cover for the module of the backlighting unit, preferably being made of optically transparent or translucent material.

[59] L’invention a encore pour objet un dispositif d’affichage obtenu par le procédé ci-dessus. [59] The invention also relates to a display device obtained by the above method.

[60] L’invention a encore pour objet un dispositif d’affichage comportant successivement, dans un empilement : [60] The invention also relates to a display device comprising successively, in a stack:

- une plaque de couverture de forme courbe, cette plaque de couverture étant notamment à base de verre ou à base de PC transparent ; - a curved cover plate, this cover plate being in particular made of glass or transparent PC;

- une structure d’affichage de forme courbe, cette structure d’affichage étant notamment de type TFT, la forme courbe de la structure d’affichage résultant d’un formage à froid ; - a curved display structure, this display structure being in particular of the TFT type, the curved shape of the display structure resulting from cold forming;

- un organe de maintien présentant une forme courbe épousant sensiblement celle de la plaque de couverture, et configuré pour maintenir structure d’affichage avec la forme courbe obtenu du formage à froid. - a holding member having a curved shape substantially matching that of the cover plate, and configured to hold the display structure with the curved shape obtained from cold forming.

[61 ] Selon l’un des aspects de l’invention, la plaque de couverture est courbe au moins dans une zone périphérique de la plaque de couverture, à savoir une zone qui est adjacente au pourtour de la plaque de couverture. [61] According to one aspect of the invention, the cover plate is curved at least in a peripheral area of the cover plate, namely an area which is adjacent to the periphery of the cover plate.

[62] Selon l’un des aspects de l’invention, la plaque de couverture est courbe sur la totalité de sa superficie. [62] According to one aspect of the invention, the cover plate is curved over its entire surface area.

[63] Dans ce cas, la plaque de couverture ne comprend aucune parcelle plane. [63] In this case, the cover plate does not include any flat plot.

[64] D’autres caractéristiques et avantages de l’invention apparaîtront plus clairement à la lecture de la description suivante, donnée à titre d’exemple illustratif et non limitatif, et du dessin annexé sur lequel : [64] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given as an illustrative and non-limiting example, and the attached drawing in which:

[65] - la [Figure 1 ] illustre, schématiquement et partiellement, des étapes d’un procédé de fabrication selon un exemple de réalisation de l’invention ; [65] - [Figure 1] illustrates, schematically and partially, steps of a manufacturing method according to an exemplary embodiment of the invention;

[66] - la [Figure 2] illustre, schématiquement et partiellement, le dispositif d’affichage obtenu par le procédé de la figure 1 , en vue éclatée ; [66] - [Figure 2] illustrates, schematically and partially, the display device obtained by the method of Figure 1, in exploded view;

[67] - la [Figure 3] illustre, schématiquement et partiellement, des étapes d’un procédé de fabrication selon un autre exemple de réalisation de l’invention ; [68] - la [Figure 4] illustre, schématiquement et partiellement, en coupe, un dispositif d’affichage selon un autre exemple de réalisation de l’invention ; [67] - [Figure 3] illustrates, schematically and partially, steps of a manufacturing method according to another exemplary embodiment of the invention; [68] - [Figure 4] illustrates, schematically and partially, in section, a display device according to another exemplary embodiment of the invention;

[69] - la [Figure 5] illustre, schématiquement et partiellement, en coupe, un organe de maintien d’un dispositif d’affichage selon un exemple de réalisation de l’invention. [69] - [Figure 5] illustrates, schematically and partially, in section, a member for holding a display device according to an exemplary embodiment of the invention.

[70] On a représenté, sur la figure 1 , des étapes d’un procédé de fabrication d’un dispositif d’affichage 1 selon un exemple de réalisation de l’invention, comportant les étapes suivantes : [70] Figure 1 shows steps of a method for manufacturing a display device 1 according to an exemplary embodiment of the invention, comprising the following steps:

- fournir une plaque de couverture 10 de forme courbe, cette plaque de couverture 10 étant à base de verre ou à base de PC transparent, la courbure de cette plaque de couverture étant obtenue au préalable par thermoformage ; - providing a curved cover plate 10, this cover plate 10 being made of glass or transparent PC, the curvature of this cover plate being obtained beforehand by thermoforming;

- fournir une structure d’affichage 20 globalement plane, cette structure d’affichage étant de type TFT (pour « Thin-film transistor » en anglais ou Transistor en couches minces) ; - provide a generally planar display structure 20, this display structure being of the TFT type (for “Thin-film transistor” in English or Thin-film transistor);

- fournir un organe de maintien 30 présentant une forme courbe épousant sensiblement celle de la plaque de couverture 10 ; - provide a holding member 30 having a curved shape substantially matching that of the cover plate 10;

- placer la structure d’affichage 20 globalement plane entre la plaque de couverture 10 et l’organe de maintien 30 (étape 1A) ; - placing the generally flat display structure 20 between the cover plate 10 and the holding member 30 (step 1A);

- appliquer une pression sur l’empilement 50 ainsi formé, pour déformer la structure d’affichage 20 de sorte qu’elle épouse la forme de la plaque de couverture 10 et de l’organe de maintien 30, l’application de la pression étant réalisée à froid (étape 1 B) ; - applying pressure to the stack 50 thus formed, to deform the display structure 20 so that it matches the shape of the cover plate 10 and the holding member 30, the application of the pressure being carried out cold (step 1 B);

- retirer l’empilement 50 en laissant à demeure l’organe de maintien 30 fixé à la structure d’affichage 20 (étape 1 C). - remove the stack 50 while leaving the holding member 30 fixed to the display structure 20 (step 1 C).

[71 ] La plaque de couverture 10 est préalablement mise sous forme courbe, par thermoformage, avec apport de chaleur. [71] The cover plate 10 is first shaped into a curved form, by thermoforming, with the addition of heat.

[72] Ainsi, dans l’invention, la plaque de couverture 10 et l’organe de maintien 30 sont initialement de forme courbe tandis que structure d’affichage 20 est initialement globalement plane. La mise en forme de la structure d’affichage 20 se fait ainsi en subissant une pression à froid, en étant prise en sandwich entre la plaque de couverture 10 et l’organe de maintien 30. [72] Thus, in the invention, the cover plate 10 and the holding member 30 are initially curved in shape while the display structure 20 is initially generally flat. The shaping of the display structure 20 is thus done by undergoing cold pressure, by being sandwiched between the cover plate 10 and the holding member 30.

[73] Comme la plaque de couverture 10 est mise sous forme courbe par thermoformage à chaud, la forme de la plaque de couverture 10 est stable. [73] Since the cover plate 10 is formed into a curved shape by hot thermoforming, the shape of the cover plate 10 is stable.

[74] Au contraire, la structure d'affichage 20 subit un formage à froid avec comme conséquence, que la structure d'affichage 20 n'est pas stable. Ainsi, la structure d'affichage 20 subit des contraintes internes du fait de la courbure que prend la structure d'affichage. La structure d'affichage 20 n'est pas formée à chaud car cela nécessiterait un procédé complexe et coûteux. [74] On the contrary, the display structure 20 undergoes cold forming with the consequence that the display structure 20 is not stable. Thus, the display structure 20 undergoes internal stresses due to the curvature that the display structure takes. The display structure 20 is not hot formed because this would require a complex and expensive process.

[75] En l'absence de l'organe de maintien 30, les contraintes internes peuvent avoir un impact sur des couches qui composent la structure d’affichage 20. Dans le cas où la structure d'affichage est de type TFT avec différentes couches dont une couche de cristaux liquides, certaines de ces couches peuvent, sous l'effet de contraintes internes dues à la courbure, se décoller l’une de l’autre, ce qui génère des zones de non-uniformité au sein de la structure d'affichage accompagnées d’effet Mura indésirable. [75] In the absence of the holding member 30, the internal stresses can have an impact on layers which make up the display structure 20. In the case where the display structure is of the TFT type with different layers including a liquid crystal layer, some of these layers can, under the effect of internal stresses due to the curvature, detach from one another, which generates areas of non-uniformity within the display structure accompanied by an undesirable Mura effect.

[76] On rappelle que l'effet Mura se manifeste notamment par des défauts de d’homogénéité dans la structure d'affichage de type écran TFT. [76] It is recalled that the Mura effect manifests itself in particular by defects in homogeneity in the display structure of the TFT screen type.

[77] Il a été constaté, de manière surprenante, que grâce à l'organe de maintien 30, il est possible de supprimer ou réduire l'effet Mura. [77] It has been found, surprisingly, that thanks to the holding member 30, it is possible to eliminate or reduce the Mura effect.

[78] Il a été constaté que, grâce à l'invention la présence de l'organe de maintien 30, il est possible d'équilibrer la force exercée par la plaque de couverture 10 sur la structure d'affichage. Ce déséquilibre de contraintes sur la structure d’affichage 20 provient du fait que la plaque de couverture 10 a été déformée de manière stable (à chaud) alors que la structure d'affichage a été déformée à froid. [78] It has been found that, thanks to the invention and the presence of the holding member 30, it is possible to balance the force exerted by the cover plate 10 on the display structure. This imbalance of stresses on the display structure 20 comes from the fact that the cover plate 10 has been deformed in a stable manner (when hot) while the display structure has been deformed when cold.

Certaines des couches de la structure d'affichage ont tendance à reprendre à la forme plane après relâchement de la pression qui a servi à produire la déformation. Some of the layers of the display structure tend to return to the planar shape after the pressure that served to produce the deformation is released.

[79] En résumé, il a été constaté que l'invention permet de préserver l'équilibre des contraintes au sein de la structure d'affichage 20, ce qui permet de supprimer ou réduire l'effet Mura. [80] La déformation de la structure d'affichage 20 est réalisée à l'aide d'un outil de presse 60 configuré pour presser sur l'empilement qui repose sur un socle de presse 61 . [79] In summary, it has been found that the invention makes it possible to preserve the balance of constraints within the display structure 20, which makes it possible to eliminate or reduce the Mura effect. [80] The deformation of the display structure 20 is carried out using a press tool 60 configured to press on the stack which rests on a press base 61.

[81 ] Cette déformation est réalisée à froid, sans apport de chaleur. [81] This deformation is carried out cold, without the addition of heat.

[82] L'outil de presse 60 présente une surface d'appui avec une forme qui épouse la forme courbe de la plaque de couverture 10. [82] The press tool 60 has a bearing surface with a shape which matches the curved shape of the cover plate 10.

[83] Une couche de colle optiquement transparente 25 (en anglais « Optical Clear Adhesive » ou OCA) est déposée entre la structure d'affichage 20 et la plaque de couverture 10. [83] A layer of optically transparent adhesive 25 (in English “Optical Clear Adhesive” or OCA) is deposited between the display structure 20 and the cover plate 10.

[84] Une autre couche de colle optiquement transparente 25 est déposée entre la structure d’affichage 20 et l'organe de maintien 30. [84] Another layer of optically transparent glue 25 is deposited between the display structure 20 and the holding member 30.

[85] La plaque de couverture 10 est une plaque en matière optiquement transparente, réalisée dans un matériau capable d'être formé à chaud. [85] The cover plate 10 is a plate of optically transparent material, made of a material capable of being hot formed.

[86] La structure d’affichage 20 comporte un substrat de base 22, en verre, qui porte des couches actives, avec des électrodes et des cristaux liquides en interaction avec les électrodes pour permettre l'affichage. [86] The display structure 20 comprises a base substrate 22, made of glass, which carries active layers, with electrodes and liquid crystals interacting with the electrodes to enable the display.

[87] La structure d’affichage 20 comporte, outre le substrat de base 22, une plaque supérieure 24, en verre, qui est destinée à venir en regard de la plaque de couverture 10, comme illustré sur la figure 2. [87] The display structure 20 comprises, in addition to the base substrate 22, an upper plate 24, made of glass, which is intended to come opposite the cover plate 10, as illustrated in FIG. 2.

[88] Ainsi la structure d’affichage 20 peut présenter une structure multicouche, avec, sur un côté, le substrat de base 22 et, de l'autre côté, la plaque supérieure 24. [88] Thus the display structure 20 can have a multi-layer structure, with, on one side, the base substrate 22 and, on the other side, the upper plate 24.

[89] L'organe de maintien 30 se présente comme une pièce additionnelle qui fait partie intégrante du dispositif d'affichage 1 et n’est pas une pièce servant uniquement au moment de la fabrication. [89] The holding member 30 is presented as an additional part which is an integral part of the display device 1 and is not a part used only at the time of manufacture.

[90] L'organe de maintien 30 présente une face principale 31 destinée à venir en vis-à-vis de la structure d’affichage 20. [90] The holding member 30 has a main face 31 intended to come opposite the display structure 20.

[91] La face principale 31 de l'organe de maintien 30 présente une forme courbe. [91] The main face 31 of the holding member 30 has a curved shape.

[92] L’organe de maintien 30 comporte un bord 32 qui sert de rigidification à l’organe de maintien 30. [93] Le bord de rigidification 32 s’étend sur tout le pourtour de la face principale de l'organe de maintien 30, là où les contraintes internes la structure d’affichage 20 peuvent être le plus dommageables. [92] The holding member 30 comprises an edge 32 which serves to stiffen the holding member 30. [93] The stiffening edge 32 extends around the entire periphery of the main face of the holding member 30, where the internal stresses of the display structure 20 can be the most damaging.

[94] Le bord de rigidification 32 s’étend à l’opposé de la structure d’affichage 20. [94] The stiffening edge 32 extends away from the display structure 20.

[95] Le bord de rigidification 32 est réalisé d'un seul tenant avec la face principale 31 de l'organe de maintien 30. [95] The stiffening edge 32 is made in one piece with the main face 31 of the holding member 30.

[96] La face principale 31 de l'organe de maintien 30 est pleine. Ceci signifie que cette face principale n’est pas ajourée. [96] The main face 31 of the holding member 30 is solid. This means that this main face is not perforated.

[97] Dans ce cas, la face principale 31 de l'organe de maintien 30 est optiquement transparente, et le bord de rigidification 32 peut être opaque optiquement, comme illustré sur la figure 5. [97] In this case, the main face 31 of the holding member 30 is optically transparent, and the stiffening edge 32 may be optically opaque, as illustrated in FIG. 5.

[98] En variante, la face principale 31 de l'organe de maintien 30 est ajourée. [98] Alternatively, the main face 31 of the holding member 30 is perforated.

[99] Par exemple, l’organe de maintien 30 ajouré longe une bande de pourtour de la structure d’affichage 20, et forme un cadre. [99] For example, the openwork holding member 30 runs along a peripheral strip of the display structure 20, and forms a frame.

[100] Le cadre formé par l'organe de maintien 30 peut être suffisant pour maintenir la structure d'affichage stable vis-à-vis des contraintes internes provoquées par la courbure. [100] The frame formed by the holding member 30 may be sufficient to keep the display structure stable against internal stresses caused by curvature.

[101] L'organe de maintien 30 peut être réalisé dans un matériau transparent ou translucide, notamment en verre ou en PVC transparent. [101] The holding member 30 may be made of a transparent or translucent material, in particular glass or transparent PVC.

[102] Dans une variante, l'organe de maintien 30 peut être entièrement réalisée en matériau transparent optiquement. [102] In a variant, the holding member 30 may be made entirely of optically transparent material.

[103] L'organe de maintien 30 peut être réalisé par moulage par injection. [103] The holding member 30 can be produced by injection molding.

[104] Dans l’exemple de réalisation de la figure 3 (qui montre également les trois étapes 3A, 3B et 3C comme dans l’exemple de la figure 1 ), l'organe de maintien 30 peut former une plaque de maintien 35 qui est similaire, voire identique, à la plaque de couverture 10, étant transparent. [104] In the exemplary embodiment of Figure 3 (which also shows the three steps 3A, 3B and 3C as in the example of Figure 1), the holding member 30 may form a holding plate 35 which is similar, or even identical, to the cover plate 10, being transparent.

[105] La plaque de maintien et la plaque de couverture 10 peuvent présenter des formes similaires, notamment des superficies identiques. [105] The holding plate and the cover plate 10 may have similar shapes, in particular identical surface areas.

[106] L'épaisseur de la plaque de maintien 35 peut être variable. [107] La variation de l'épaisseur peut être choisie en fonction du rayon de courbure que prend la plaque de maintien 35. [106] The thickness of the holding plate 35 can be variable. [107] The variation in thickness can be chosen as a function of the radius of curvature taken by the holding plate 35.

[108] L’épaisseur de la plaque de maintien 35 et l'épaisseur de la plaque de couverture 10 peuvent être identiques. [108] The thickness of the holding plate 35 and the thickness of the cover plate 10 may be the same.

[109] Ainsi il est possible de répartir l'épaisseur de la plaque de maintien 35 et celle de la plaque de couverture 10 de part et d'autre de la structure d'affichage. [109] Thus it is possible to distribute the thickness of the holding plate 35 and that of the cover plate 10 on either side of the display structure.

[110] Le dispositif d'affichage comporte ainsi une plaque de maintien 35 et une plaque de couverture 10 entre lesquelles est fixée la structure d'affichage 20 qui a pris une forme courbe. [110] The display device thus comprises a holding plate 35 and a cover plate 10 between which the display structure 20 is fixed, which has taken a curved shape.

[111] La plaque de maintien 35, tout comme la plaque de couverture 10, présentent une forme courbe obtenue préalablement par formage à chaud. [111] The holding plate 35, like the cover plate 10, has a curved shape obtained beforehand by hot forming.

[112] Dans l’exemple de réalisation de la figure 4, l'organe de maintien 30 est configuré pour encapsuler des éléments d'une unité de rétroéclairage 70. [112] In the exemplary embodiment of Figure 4, the holding member 30 is configured to encapsulate elements of a backlight unit 70.

[113] Le module de rétroéclairage 70 comporte un boîtier 71 dans lequel sont placés une carte électronique 72 avec des sources de lumière 73 de type LED, un guide de lumière 74 au-dessus de la carte électronique 72, et au-dessus de ce guide lumière, un empilement de feuilles optiques 75. [113] The backlight module 70 comprises a housing 71 in which are placed an electronic card 72 with LED type light sources 73, a light guide 74 above the electronic card 72, and above this light guide, a stack of optical sheets 75.

[114] L'organe de maintien 30 est configuré pour fermer le boîtier 71 de l'unité de rétroéclairage 70. [114] The holding member 30 is configured to close the housing 71 of the backlight unit 70.

[115] Le dispositif d'affichage 1 est posé sur le boîtier 71 de l'unité de rétroéclairage. [115] The display device 1 is placed on the housing 71 of the backlight unit.

[116] L'organe de maintien 30 du dispositif d'éclairage vient fermer ce boîtier 71 de l'unité de rétroéclairage 70. [116] The holding member 30 of the lighting device closes this housing 71 of the backlighting unit 70.

[117] L'organe de maintien 30 du dispositif d'éclairage sert ainsi de couvercle boîtier 71 du module de l'unité de rétroéclairage, étant réalisé en matière optiquement transparente ou translucide. [117] The holding member 30 of the lighting device thus serves as a housing cover 71 of the module of the backlighting unit, being made of optically transparent or translucent material.

[118] D’une manière générale, l’invention permet d’obtenir un dispositif d’affichage comportant successivement, dans un empilement : une plaque de couverture 10 de forme courbe, cette plaque de couverture 10 étant notamment à base de verre ou à base de PC transparent ; - une structure d’affichage 20 de forme courbe, cette structure d’affichage 20 étant notamment de type TFT, la forme courbe de la structure d’affichage 20 résultant d’un formage à froid ; [118] Generally speaking, the invention makes it possible to obtain a display device comprising successively, in a stack: a cover plate 10 of curved shape, this cover plate 10 being in particular based on glass or based on transparent PC; - a display structure 20 of curved shape, this display structure 20 being in particular of the TFT type, the curved shape of the display structure 20 resulting from cold forming;

- un organe de maintien 30 présentant une forme courbe épousant sensiblement celle de la plaque de couverture 10, et configuré pour maintenir structure d’affichage 20 avec la forme courbe obtenu du formage à froid. - a holding member 30 having a curved shape substantially matching that of the cover plate 10, and configured to hold the display structure 20 with the curved shape obtained from cold forming.

[119] La plaque de couverture 10 est courbe au moins dans une zone périphérique de la plaque de couverture 10, à savoir une zone qui est adjacente au pourtour de la plaque de couverture 10. [119] The cover plate 10 is curved at least in a peripheral area of the cover plate 10, namely an area which is adjacent to the periphery of the cover plate 10.

[120] La plaque de couverture 10 est de préférence courbe sur la totalité de sa superficie. [120] The cover plate 10 is preferably curved over its entire surface area.

[121] Dans ce cas, la plaque de couverture 10 ne comprend aucune parcelle plane. [121] In this case, the cover plate 10 does not include any flat plot.

[122] La courbure de la plaque de couverture 10 peut être choisie en fonction des besoins, notamment de forme. [122] The curvature of the cover plate 10 can be chosen according to the needs, in particular the shape.

[123] L’organe de maintien peut être fait par un moulage par injection d’une matière ou de deux matières dans un même moule. Dans le cas de deux matières, l’opération de moulage est désignée comme un moulage 2K. Les matières peuvent être différentes. [123] The holding member can be made by injection molding one material or two materials in a single mold. In the case of two materials, the molding operation is referred to as 2K molding. The materials can be different.

Claims

Revendications Claims [Revendication 1 ] Procédé de fabrication d’un dispositif d’affichage (1 ), le procédé comportant les étapes suivantes : [Claim 1] A method of manufacturing a display device (1), the method comprising the following steps: - fournir une plaque de couverture (10) de forme courbe, cette plaque de couverture (10) étant notamment à base de verre ou à base de PC transparent, la courbure de cette plaque de couverture (10) étant notamment obtenue au préalable par thermoformage ; - providing a curved cover plate (10), this cover plate (10) being in particular made of glass or transparent PC, the curvature of this cover plate (10) being in particular obtained beforehand by thermoforming; - fournir une structure d’affichage (20) globalement plane, cette structure d’affichage (20) étant notamment de type TFT ; - providing a generally planar display structure (20), this display structure (20) being in particular of the TFT type; - fournir un organe de maintien (30) présentant une forme courbe épousant sensiblement celle de la plaque de couverture (10) ; - provide a holding member (30) having a curved shape substantially matching that of the cover plate (10); - placer la structure d’affichage (20) globalement plane entre la plaque de couverture (10) et l’organe de maintien (30) ; - placing the generally flat display structure (20) between the cover plate (10) and the holding member (30); - appliquer une pression sur l’empilement ainsi formé, pour déformer la structure d’affichage (20) de sorte qu’elle épouse la forme de la plaque de couverture (10) et de l’organe de maintien (30), l’application de la pression étant notamment réalisée à froid; - applying pressure to the stack thus formed, to deform the display structure (20) so that it matches the shape of the cover plate (10) and the holding member (30), the application of the pressure being carried out in particular cold; - retirer l’empilement en laissant à demeure l’organe de maintien (30) fixé à la structure d’affichage (20). - remove the stack, leaving the holding member (30) fixed to the display structure (20). [Revendication 2] Procédé selon la revendication précédente, dans lequel la plaque de couverture (10) est préalablement mise sous forme courbe, de préférence par thermoformage, avec apport de chaleur. [Claim 2] Method according to the preceding claim, in which the cover plate (10) is previously shaped into a curve, preferably by thermoforming, with the addition of heat. [Revendication 3] Procédé selon l’une des revendications précédentes, dans lequel la déformation de la structure d’affichage (20) est réalisée à l'aide d'un outil de presse configuré pour presser sur l'empilement qui repose sur un socle de presse, cette déformation étant de préférence réalisée à froid, sans apport de chaleur. [Claim 3] Method according to one of the preceding claims, in which the deformation of the display structure (20) is carried out using a press tool configured to press on the stack which rests on a press base, this deformation preferably being carried out cold, without the addition of heat. [Revendication 4] Procédé selon l’une des revendications précédentes, dans lequel une colle optiquement transparente (OCA) est déposée entre la structure d’affichage (20) et la plaque de couverture (10), notamment une colle optiquement transparente (OCA) est déposée entre la structure d’affichage (20) et l'organe de maintien (30). [Claim 4] Method according to one of the preceding claims, in which an optically transparent adhesive (OCA) is deposited between the display structure (20) and the cover plate (10), in particular a optically clear adhesive (OCA) is deposited between the display structure (20) and the holding member (30). [Revendication 5] Procédé selon l’une des revendications précédentes, dans lequel la structure d’affichage (20) comporte un substrat de base, notamment en verre, qui porte des couches actives, notamment avec des électrodes et des cristaux liquides en interaction avec les électrodes pour permettre l'affichage. [Claim 5] Method according to one of the preceding claims, in which the display structure (20) comprises a base substrate, in particular made of glass, which carries active layers, in particular with electrodes and liquid crystals interacting with the electrodes to enable the display. [Revendication 6] Procédé selon l’une des revendications précédentes, dans lequel la plaque de couverture (10) est une plaque en matière optiquement transparente, réalisée dans un matériau capable d'être formé à chaud. [Claim 6] A method according to any preceding claim, wherein the cover plate (10) is a plate of optically transparent material, made of a material capable of being hot formed. [Revendication 7] Procédé selon l’une des revendications précédentes, dans lequel la structure d’affichage (20) comporte, outre un substrat de base notamment en verre, une plaque supérieure, notamment en verre, qui est destinée à venir en regard de la plaque de couverture (10). [Claim 7] Method according to one of the preceding claims, in which the display structure (20) comprises, in addition to a base substrate, in particular made of glass, an upper plate, in particular made of glass, which is intended to come opposite the cover plate (10). [Revendication 8] Procédé selon l’une des revendications précédentes, dans lequel l'organe de maintien (30) se présente comme une pièce additionnelle qui fait partie intégrante du dispositif d'affichage. [Claim 8] Method according to one of the preceding claims, in which the holding member (30) is presented as an additional part which is an integral part of the display device. [Revendication 9] Procédé selon l’une des revendications précédentes, dans lequel l'organe de maintien (30) présente une face principale destinée à venir en vis-à-vis de la structure d'affichage, et la face principale de l'organe de maintien (30) présente une forme courbe. [Claim 9] Method according to one of the preceding claims, in which the holding member (30) has a main face intended to come opposite the display structure, and the main face of the holding member (30) has a curved shape. [Revendication 10] Procédé selon l’une des revendications précédentes, dans lequel l’organe de maintien (30) comporte un bord qui sert de rigidification à l’organe de maintien (30), et le bord de rigidification s’étend notamment sur tout le pourtour de la face principale de l'organe de maintien (30). [Claim 10] Method according to one of the preceding claims, in which the holding member (30) comprises an edge which serves to stiffen the holding member (30), and the stiffening edge extends in particular around the entire periphery of the main face of the holding member (30). [Revendication 11] Procédé selon l’une des revendications précédentes, dans lequel l'organe de maintien (30) est configuré pour encapsuler des éléments d'une unité de rétroéclairage, et le module de rétroéclairage comporte un boîtier dans lequel sont placés un support avec des sources de lumière notamment de type LED, un guide de lumière au-dessus du support avec des sources de lumière, et au-dessus de ce guide lumière, un empilement de feuilles optiques. [Claim 11] Method according to one of the preceding claims, in which the holding member (30) is configured to encapsulate elements of a backlighting unit, and the backlighting module comprises a housing in which a support with light sources, in particular of the LED type, is placed, a light guide above the support with light sources, and above this light guide, a stack of optical sheets. [Revendication 12] Dispositif d’affichage (1 ) comportant successivement, dans un empilement : [Claim 12] Display device (1) successively comprising, in a stack: - une plaque de couverture (10) de forme courbe, cette plaque de couverture (10) étant notamment à base de verre ou à base de PC transparent ; - a curved cover plate (10), this cover plate (10) being in particular made of glass or transparent PC; - une structure d’affichage (20) de forme courbe, cette structure d’affichage (20) étant notamment de type TFT, la forme courbe de la structure d’affichage (20) résultant d’un formage à froid ; - a display structure (20) of curved shape, this display structure (20) being in particular of the TFT type, the curved shape of the display structure (20) resulting from cold forming; - un organe de maintien (30) présentant une forme courbe épousant sensiblement celle de la plaque de couverture (10), et configuré pour maintenir structure d’affichage (20) avec la forme courbe obtenu du formage à froid. - a holding member (30) having a curved shape substantially matching that of the cover plate (10), and configured to hold the display structure (20) with the curved shape obtained from cold forming.
PCT/EP2024/079985 2023-10-25 2024-10-23 Process for manufacturing a display device Pending WO2025087990A1 (en)

Applications Claiming Priority (2)

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FRFR2311601 2023-10-25
FR2311601A FR3154843A1 (en) 2023-10-25 2023-10-25 Method of manufacturing a display device

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WO2025087990A1 true WO2025087990A1 (en) 2025-05-01

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230095460A1 (en) * 2012-06-29 2023-03-30 Samsung Display Co., Ltd. Display device, and method and apparatus for manufacturing the same
US20230311661A1 (en) * 2017-10-10 2023-10-05 Corning Incorporated Vehicle interior systems having a curved cover glass with improved reliability and methods for forming the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230095460A1 (en) * 2012-06-29 2023-03-30 Samsung Display Co., Ltd. Display device, and method and apparatus for manufacturing the same
US20230311661A1 (en) * 2017-10-10 2023-10-05 Corning Incorporated Vehicle interior systems having a curved cover glass with improved reliability and methods for forming the same

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