DE102017221079A1 - CURVED DISPLAY AND MANUFACTURING METHOD - Google Patents

Abstract

The present invention relates to a manufacturing method for a curved display element, in particular for a curved glass or plastic cover connected to a display panel or a plurality of display panels, and to a corresponding product. The binder used is preferably an OCA silicone adhesive. In this case, the display panel or the display panels are first connected in the flat state with the cover and post-treated in a vacuum, which allows a particularly simple and accurate alignment. Only then is the final curved shape of the display element produced by joining with a prefabricated in the desired curved shape support material (support frame).

Description

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to curved display devices with a glass or transparent plastic cover. In particular, the present invention relates to a manufacturing method for such display devices.

State of the art

Recently, screens having a curved (curved, curved) surface are increasingly being used for various applications instead of flat screens.

Fields of application of such displays are diverse and range - without any claim to completeness - from office monitors via smartphones to applications in automotive technology. Curved displays have a number of advantages over flat panel displays, such as better matching the field of view to human viewing habits by adapting the curvature to that of the human eye, creating a spatial effect when viewed, and reducing the disturbing influence of ambient light.

In the field of automotive engineering, it is also of particular advantage that the displays with curved surface better and more flexible to the circumstances of the environment, i. the design of the vehicle interior can be adjusted. This allows the vehicle designer more design freedom than with the exclusive use of flat screens.

Curved screens, however, are associated with additional manufacturing challenges over flat panel displays.

Generally speaking, a display (monitor) comprises a display panel (or multiple display panels) covered by a transparent cover (typically a glass or transparent plastic panel). This cover may additionally be provided on its underside with a touch-sensitive layer (touch panel) (touch screen).

The display panel can be implemented either as a passive display panel in liquid crystal display (LCD) technology or as an active display panel with self-illuminating pixels.

In the case of a passive display panel, the individual pixels of the display panel themselves emit no light. Instead, a backlight is provided, so there is a radiation from the background of the display, from the cover opposite side. A backlight and its implementation is not the subject of the present invention, i. a passive display panel product made by the method of the present invention includes only the passive display panel and the cover; the backlight has to be additionally implemented separately in this case.

In the case of an active display field, even luminous pixels are used, eliminating the need for backlighting. Today, organic light-emitting diodes (OLEDs) are used here in particular. A particular embodiment is an active matrix of organic light-emitting diodes (AMOLED).

A preferred embodiment for the implementation of both LCD and OLED displays is thin film transistor (TFT) technology.

The multilayer assembly comprising the cover and one or more display panels is typically terminated by a backing layer or base layer on the opposite side of the cover.

For the production of curved or curved monitors (displays, display devices, screens), methods are known in which the individual elements (layers) are first brought into the required curved (arched, curved) shape individually, and then joined together. However, this has the disadvantage that the joining (joining) of curved surfaces (by gluing or "bonding"), in particular with the required in the manufacture of displays accuracy in the alignment of the individual components (alignment), is relatively difficult.

SUMMARY OF THE INVENTION

The present invention aims to provide a manufacturing method for an assembly for a curved display device, comprising a curved cover connected to a display panel, with which the components of the display device can be mounted with the highest possible accuracy, and to provide a corresponding assembly.

This is achieved with the features of the main claim 1 and the independent claim 11.

According to a first aspect of the present invention, there is provided a manufacturing method for an assembly of a curved display, the assembly comprising a display panel and a curved cover connected thereto. The method comprises the following steps, performed in the order given: applying a layer of bonding material to a surface of the cover, in the unbent state, connecting the display panel to the cover over the binding material and connecting the cover connected to the display panel to one in the desired bending shape prefabricated and provided with an adhesive material support frame made of plastic or metal, wherein the cover is bent so that its shape is adapted to the prefabricated bending shape of the support frame.

It is the particular approach of the present invention to first bond (bond) the two major components of a curved display device, namely display panel and cover, in the unbent (not curved, i.e., "flat") condition. As a result, a high accuracy is achieved. A deformation into the desired curved shape takes place only in a final process step, in which the already connected to the display panel cover with an adhesive material with a metallic or plastic support frame (base or "frame") is connected. For this purpose, the support frame is brought into the desired shape in advance and provided with the adhesive material. The shape of the glass cover connected to the display panel adapts to the prefabricated form of the support frame. As the adhesive material, for example, a liquid adhesive or double-sided adhesive tape can be used.

Preferably, the cover comprises a layer of glass or plastic.

Preferably, the method according to the invention initially comprises the additional step of cleaning the surfaces of the cover and the display panel to be joined together.

Preferably, the production is carried out by means of a template. Here, the cover is first introduced in the unbent state in a lower part of the template and then applied the layer of binding material on the still free surface. The template is preferably designed so that it can be hermetically sealed by means of an upper part and within the closed stencil a vacuum can be generated. The connection between the cover and the binding material is in this case consolidated in the vacuum, since the adhesion is improved.

Further preferably, the template is also used for the connection of the display panel with the cover. For this purpose, the cover connected to the binding material is first removed from the template and the display panel, again in the unbent state, introduced into a predetermined position (recess) of the template. Subsequently, the cover with the applied binding material is placed on the display panel inserted into the template, so that the binding material establishes a connection between the cover and the display panel. Thereafter, the stencil is closed again and the bond between the binding material and the display panel is vacuum tightened.

In addition, the aftertreatments in vacuum prevent blistering in the spaces between the cover and the binding material and between the binding material and the display panel.

Also preferably, the manufacturing method further comprises the step of applying an adhesive material to a prefabricated in the desired bending shape support frame made of plastic or metal. This step is of course to be carried out prior to the step of applying the cover connected to the display panel to the support frame, in particular it may be performed immediately before this step, and may also be carried out at an earlier time. In particular, this step may be performed in parallel with the previous steps involving the connection of the cover and the display panel.

According to a preferred embodiment, the binding material is provided in the form of a layer which is provided with a protective film on both surfaces. In this case, the method further comprises the steps of removing the protective film from the surface of the binder material layer applied to the cover, and removing the protective film from the surface of the binder material layer to be bonded to the display panel. Of course, the first step mentioned above must be carried out before applying the binder material layer to the cover. Of course, the second step must be carried out before connecting the display panel to the cover, and is preferably carried out immediately before this connection, i. at a time when the bond between the binding material and the cover already exists and is strengthened.

Preferably, the binder material is a silicone adhesive, more preferably a so-called OCA [Optical Clear Adhesive] silicone adhesive. This is in particular in thin, provided with protective films (protective films) layers for processing.

Preferably, the display panel is a liquid crystal display panel (LCD). Further preferably, the display panel is implemented in thin-film transistor technology (TFT).

Since a liquid crystal display panel is not self-luminous, a backlight must be additionally implemented in this case. For this purpose, the support frame is made to have, in the area in which the display panel is located after assembly, a recess through which the backlighting light can strike the rear of the display panel.

According to an alternative preferred embodiment, the display panel comprises organic light-emitting diodes. Further preferably, the display panel comprises an active matrix of organic light emitting diodes (AMOLED). Such an active display with organic light emitting diodes can also be implemented in TFT technology.

In this case, recesses in the support frame can be dispensed with, i. this can be carried out as a continuous layer. Such a layer may also serve as the back cover of the entire structure, thus fulfilling, in addition to the task of stabilizing the bent shape, also the function of an outer protective layer.

According to a preferred embodiment, the cover is made of glass or plastic.

Alternatively, preferably, the cover additionally has a touch panel (touch panel). Here, the touchpad is bonded to a surface of a layer of glass or plastic prior to the step of applying a layer of bonding material such that the cover comprises a layer of glass or plastic and the touchpad prior to the step of applying the bonding material. This compound is made with a binder material which can be provided, for example, in the form of a layer or in liquid form. The binding material is then applied in the step of applying to the free surface of the touchpad. The touchpad is thus located on the underside of the cover of the display.

According to another aspect of the present invention, there is provided a curved cover connected to a display panel manufactured by the manufacturing method according to the first aspect.

Further features and advantages of the present invention are the subject of dependent claims.

list of figures

• 1a bis 1h eine bildliche Darstellung einzelner Verarbeitungsschritte eines Herstellungsverfahrens gemäß einer Ausführungsform der vorliegenden Erfindung sind;
• 2 eine Darstellung eines mit dem erfindungsgemäßen Herstellungsverfahren erzeugten Produkts ist;
• 3 ein Ausschnittsdetail des in 2 dargestellten Produkts zeigt; und
• 4 ein Ablaufdiagramm eines Herstellungsverfahrens gemäß einer Ausführungsform der vorliegenden Erfindung ist.

Additional features and advantages of the present invention will be set forth below in the detailed description and illustrated in the accompanying drawings, in which:

• 1a to 1h FIG. 4 is a pictorial representation of individual processing steps of a manufacturing method according to an embodiment of the present invention; FIG.
• 2 is an illustration of a product produced by the manufacturing method of the invention;
• 3 a detail of the detail in 2 shown product; and
• 4 Fig. 10 is a flowchart of a manufacturing method according to an embodiment of the present invention.

In the various figures, the same reference numerals designate the same or corresponding features, so that a renewed description is optionally omitted.

DETAILED DESCRIPTION

The present invention relates to a bonding process for a curved display with a cover glass (or a plastic cover). In a preferred embodiment, an OCA silicone adhesive, an open-cell display panel and a flexible cover glass are used in this case. An open-cell display panel is not connected to the backlight and therefore can still be bent. Alternatively, however, the present invention is also applicable to self-luminous display panels, especially OLEDs, especially AMOLEDs, which do not require backlighting.

For the manufacturing method according to the embodiment described in detail below, a vacuum generator and a template for the alignment of the individual components is further used.

However, the present invention as defined in the claims, is not on the im the following detailed procedure described and the method steps described in detail limited.

The basic idea of the present invention is that the bonding process, that is the assembly of the display panel and cover, is carried out before these components are bent, i. as long as they are still flat. Only then is the already assembled combination of cover and display panel brought into the curved shape with the help of the mechanical structure of the support frame and held in this.

1. 1. wird das Bindematerial (Silikonfilm) auf die Abdeckung aufgetragen,
2. 2. wird das Anzeigefeld mit dem Bindematerial verbunden und
3. 3. wird die gesamte Struktur (Abdeckung + Bindematerial + Anzeigefeld) in die gewünschte Form gebracht.

In summary, the manufacturing process is carried out in 3 main steps:

1. 1. the binding material (silicone film) is applied to the cover,
2. 2. the display panel is connected to the binding material and
3. 3. the entire structure (cover + binding material + display panel) is brought into the desired shape.

These steps are described below with reference to the flow chart of 4 and the detailed representations of the 1 explained with reference to an embodiment.

As stated above, this embodiment is only for the purpose of illustrating and not limiting the invention defined by the claims.

In the embodiment described below, two display panels are simultaneously bonded to the cover glass or the plastic cover, however, the manufacturing process is not limited to this case but also applicable to the bonding of only one or a different number of display panels.

In the introductory step S1 First, the surfaces of the cover and the display panel (the display panel) to be joined together are cleaned. The surfaces to be joined by bonding must be very well cleaned to avoid the influence of foreign particles (particles). The entire manufacturing process should therefore preferably in a clean room (at least ISO class 7 ).

In the following step S2 will the cover 1 in the template 2a positioned. This is in 1a shown. The cover 1 is a thin plastic or glass plate, preferably with a thickness below 1 millimeter (for example, 0.7 mm), which may already be provided on its underside with a touch panel. The cover 1 gets into the template 2a (Preferably, a metal template produced by the CNC method) introduced and thereby prepared for bonding.

Subsequently (or temporally parallel) is in the step S3 the lower protective film 4b from the binding material 3 deducted. More specifically, the protective film becomes 4b from that side of the layered with protective films 4a and 4b provided binding material 3 removed with the surface of the cover 1 to be connected. This process is in 1b shown.

In the subsequent step S4a becomes the binding material 3 with the of the protective film 4b liberated surface on the after insertion into the template 2a still free surface of the cover 1 placed. Immediately thereafter, in step S 4 b a post-treatment carried out in vacuo. These two steps (summarized: step S4 ) are in 1c shown schematically. Around a vacuum chamber 5 to realize the template 2a in the embodiment shown by an upper template part 2 B completed and completed airtight with this. Subsequently, using a vacuum pump (vacuum generating device) 6 creates a vacuum in the vacuum chamber.

In the following step S5 will the cover 1 (with the binding material already attached 3 ) first removed from the template. Subsequently, the display fields in their place 7 (For example, LCD panels or OLED fields) inserted in specifically provided receiving spaces (recesses) of the template (in the example shown, they are located in the template part 2 B previously used as upper degree). This step is in 1d shown.

In the following step S6 (shown in 1e) is now from the already with the cover 1 connected bonding material layer 3 also the upper protective film 4a that is, it is the protective film of the after application to the cover 1 still free surface of the binding material layer 3 away.

Subsequently, in step S 7 already with the binding material 3 provided cover 1 with the free surface of the binding material 3 on the free surface in the template 2 B located display fields 7 put on and so with the display fields 7 connected. Immediately thereafter, in step S7b the template 2 B again with the help of an upper template part (in this case in the example in the step S4 lower template part 2a) closed and with the help of the vacuum pump 6 creates a vacuum. In the resulting vacuum chamber 5 becomes the newly created bond between the binder material layer 3 and the display fields 7 aftertreated and strengthened. These two steps (summarized: step S7 ) are in 1f shown schematically. Subsequently, the vacuum chamber 5 open and the with the display fields 7 connected cover 1 is taken from the template.

Prior to or parallel to the steps described above, the support frame becomes 8th in step S8 for joining with cover 1 and display fields 7 prepared. For this purpose, the previously brought into the desired curved shape support frame 8th with an adhesive material 9 Provided. This process is in 1g shown.

As already stated, the support frame 8th be designed differently depending on the embodiment within the scope of the invention.

This may in particular be a continuous carrier layer, which terminates the entire structure on the opposite side of the viewing surface and thus also provides the required dimensional stability. Such an embodiment is particularly in question when self-luminous display panels are used, so that can be dispensed with a backlight.

Alternatively, the support frame may be configured as a scaffold or "skeleton", ie have larger recesses through which the light from a backlight, which then on the of the display panel 7 opposite side of the support frame 8th to arrange is (not shown in the picture) on the display fields 7 can hit. In 1g (as well as in the following 1h) Such recesses are not shown, so the representation either corresponds to an embodiment without such recesses, or it can be assumed that the cutting plane of the drawing in a range (approximately at the edge of the display fields 7 ) is located in which there are no recesses.

As adhesive material 9 Preferably, a liquid adhesive or a double-coated adhesive tape is used.

After completion of the vacuum post-treatment in step S7b takes place in the final step S9 represented in 1h , now joining the prefabricated structure of cover 1 and display fields 7 with the support frame 8th over the adhesive material 9 like this in the 1h indicated by the arrows. Here is the cover 1 made of glass or plastic bent so that their shape matches that of the preformed support frame 8th adapts.

The result of the manufacturing process is in 2 shown in a sectional drawing.

It is in the case of 2 an embodiment with a skeleton or skeletal support frame 8th (with recesses) shown and the sectional plane of the drawing chosen so that the recesses in the support frame 8th are recognizable. As a result, are carrier frames 8th and adhesive material 9 in the field of display fields 7 shown interrupted.

A detailed view of the product thus produced, corresponding to a section of the 2 inside the circle, is in 3 shown in a detail enlargement. In this is additionally an optional black color coating 10 the back of the cover shown the representations of the 1 and 2 has been omitted for clarity. This coating is frame-shaped so as to cover an area where the cover is not connected to a display panel. It is thereby achieved that the cover as a whole shows transparency only where it is connected to display fields (in the case illustrated, there are two).

In summary, the present invention relates to a manufacturing method for a curved display element, in particular for a curved glass or plastic cover connected to a display panel or a plurality of display panels, and to a corresponding product. The binder used is preferably an OCA silicone adhesive. In this case, the display panel or the display panels are first connected in the flat state with the cover and post-treated in a vacuum, which allows a particularly simple and accurate alignment. Only then is the final curved shape of the display element produced by joining with a prefabricated in the desired curved shape support material (support frame).

Claims (11)

A method of manufacturing a bent display assembly, the assembly comprising a display panel (7) and a curved cover (1) connected thereto, and wherein the method comprises the steps of: applying (S4) a layer of binder material (3) On a surface of the cover (1), in the unbent state, connecting (S7) the display panel (7) to the cover (1) via the binding material (3) and connecting (S9) connected to the display panel (7) Cover (1) on a prefabricated in the desired bending shape and with an adhesive material (9) provided plastic or metal support frame (8), wherein the cover (1) is bent so that its shape is adapted to the prefabricated bending shape of the support frame (8). Production method according to Claim 1 wherein the step of applying a layer of bonding material (3) to a surface of the cover (1) comprises the steps of placing (S2) the cover, in the unbent state, in a template (2a), applying (S4a) the layer Binding material (3) on the free surface of the cover (1) and closing the template (2a, 2b) and connecting (S4b) in a vacuum. Production method according to Claim 1 or 2 wherein the step of connecting the display panel (7) to the cover (1) comprises the steps of: inserting (S5) the display panel (7), in the unbent state, into a predetermined recess of a template (2b), seating (S7a) Cover (1) with the applied binding material (3) on the in the template (2b) introduced display field (7), so that the binding material (3) establishes a connection between the cover (1) and the display panel (7) and closing the Template (2a, 2b) and connecting (S7b) in vacuum. Manufacturing method according to one of Claims 1 to 3 further comprising the step (S8) of applying an adhesive material (9) to a plastic or metal support frame (8) prefabricated in the desired bending shape, to be performed before the step (S9) of joining the cover (7) connected to the display panel (7). 1) on the support frame (8). Manufacturing method according to one of Claims 1 to 4 in that the binding material (3) is provided in the form of a layer provided with a protective film (4a, 4b) on both surfaces, the method further comprising the steps of: removing (S3) the protective film (4b) from the surface of the Bonding material layer (3) applied to the cover (1), before the step (S4) of applying the layer of bonding material (3) to the cover (1) and removing (S6) the protective film (4a) from the surface the binding material layer (3) to be connected to the display panel (7), before the step (S7) of connecting the display panel (7) to the cover (1). Manufacturing method according to one of Claims 1 to 5 wherein the bonding material (3) is an OCA [Optical Clear Adhesive] silicone adhesive. Manufacturing method according to one of Claims 1 to 6 wherein the display panel (7) is a liquid crystal display panel. Production method according to Claim 7 , wherein the display panel (7) is implemented in thin-film transistor technology. Manufacturing method according to one of Claims 1 to 6 , wherein the display panel (7) comprises organic light-emitting diodes, in particular an active matrix of organic light-emitting diodes [AMOLED]. Manufacturing method according to one of Claims 1 to 9 in which the cover (1) has a touch panel, wherein the touch panel has been bonded to a surface of a layer of glass or plastic prior to the step (S4) of applying a layer of bonding material (3), and the bonding material in the step (5) S4) of the application is applied to the free surface of the touch panel, so that the touch panel after completion of the manufacturing process at the bottom of the cover (1). Assembly for a display, comprising a curved cover (1) connected to a display panel (7), produced by the manufacturing method according to one of the preceding claims.

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