KR102633501B1 - Foldable display device - Google Patents

Abstract

This specification discloses a foldable display device. The foldable display device includes a display panel having two or more flat areas and a folding area between the flat areas; It is located on one side of the display panel and includes a multi-layered support member supporting the display panel, wherein the support member has an opening pattern in a region corresponding to the folded region.

Description

Foldable display device {FOLDABLE DISPLAY DEVICE}

This specification relates to a foldable display device.

Video display devices, which display various information on a screen, are a core technology of the information and communication era and are developing to be thinner, lighter, more portable, and more high-performance. Accordingly, organic light emitting display devices that display images by controlling the amount of light emitted from organic light emitting elements are receiving attention.

Organic light-emitting devices are self-luminous devices that use a thin light-emitting layer between electrodes and have the advantage of being able to be made into thin films. A typical organic light emitting display device has a structure in which a pixel driving circuit and an organic light emitting element are formed on a substrate, and the light emitted from the organic light emitting element passes through the substrate or barrier layer to display an image.

Since the organic light emitting display device is implemented without a separate light source device, it is easy to be implemented as a flexible, bendable, or foldable display device. At this time, flexible materials such as plastic and thin metal foil are used as substrates for organic light emitting display devices. Additionally, flexible and foldable display devices, etc., generally have multiple thin film layers stacked on a substrate.

For example, a foldable display device may be composed of several functional films and a series of adhesive layers for their lamination. Due to its nature, foldable display devices need to be quickly restored to their original state and flat after being folded and unfolded, but the materials currently used have limitations in complete restoration, and their restoration properties may further deteriorate in high-temperature/high-humidity environments. Accordingly, in order to improve the usability of foldable display devices, material or structural improvements are being requested to ensure flexibility and restoration.

The purpose of this specification is to propose a foldable display device and a folding structure used therein. The tasks of this specification are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

A foldable display device is provided according to an embodiment of the present specification. The foldable display device includes a display panel having two or more flat areas and a folding area between the flat areas; It is located on one side of the display panel and includes a multi-layered support member supporting the display panel, wherein the support member has an opening pattern in a region corresponding to the folded region. .

The support member includes: a first metal layer below the display panel; and a second metal layer below the first metal layer and having an opening pattern in an area corresponding to the folded area, wherein the first metal layer may not have an opening pattern in an area corresponding to the folded area. .

The second metal layer may be thicker than the first metal layer.

The support member may further include a third metal layer below the second metal layer and having an opening pattern in a region corresponding to the folded region.

The third metal layer may be thicker than the second metal layer.

The third metal layer may have a wider opening pattern than the second metal layer.

The first metal layer can reduce screen unevenness due to the opening pattern in the second metal layer or the third metal layer.

The opening pattern may be a slit extending in a direction parallel to the folding axis.

The opening pattern may have at least one shape selected from the group consisting of a rectangle, a diamond, an oval, and a rectangle with rounded corners.

At least some of the opening patterns may be filled with silicon.

It may further include an adhesive layer between the display panel and the support member.

The second metal layer or the third metal layer may also have an opening pattern in a region corresponding to the flat region.

Specific details of other embodiments are included in the detailed description and drawings.

Embodiments of the present specification can provide a support structure suitable for the dynamic behavior of a foldable display device. Furthermore, embodiments of the present specification can provide an adhesive member that enhances the folding characteristics and resilience of a foldable display device. Furthermore, the foldable display device can improve screen unevenness in the folded area. The effects according to the embodiments of the present specification are not limited to the contents exemplified above, and further various effects are included in the present specification.

1 shows an example foldable display device.
Figure 2 is a cross-sectional view showing a portion of the display panel included in the display device of this specification.
3A and 3B are diagrams illustrating a foldable display device according to an embodiment of the present specification.
4A to 4C are cross-sectional views showing a foldable display device according to an embodiment of the present specification.
5A to 5D are diagrams illustrating the shape of an opening pattern applied to a support member according to an embodiment of the present specification.
6A to 6D are diagrams illustrating the arrangement of opening patterns applied to a support member according to an embodiment of the present specification.

The advantages and features of the present specification and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining the embodiments of the present specification are illustrative, and the present specification is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise. When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used. When an element or layer is referred to as “on” another element or layer, it includes instances where the other layer or other element is directly on top of or interposed between the other elements. When a component is described as being “connected,” “coupled,” or “connected” to another component, that component may be directly connected or connected to that other component, but there are no other components between each component. It should be understood that may be “interposed” or that each component may be “connected,” “combined,” or “connected” through other components.

Although first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, the first component mentioned below may also be the second component within the technical spirit of the present invention.

The size and thickness of each component shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the components shown. Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

1 shows an example foldable display device.

The foldable display device 1000 may include at least one active area. For example, a foldable display device may have multiple display areas divided into left and right (or top and bottom) based on a folding line. An array of pixels is formed in the display area. One or more inactive areas may be placed around the display area. That is, the non-display area may be adjacent to one or more sides of the display area. In Figure 1, the non-display area surrounds a rectangular display area. However, the shape of the display area and the shape/arrangement of the non-display area adjacent to the display area are not limited to the example shown in FIG. 1. The display area and the non-display area may have a shape suitable for the design of an electronic device equipped with the display device 1000. Exemplary shapes of the display area include pentagon, hexagon, circle, oval, etc.

Each pixel within the display area may be associated with a pixel circuit. The pixel circuit may include one or more switching transistors and one or more driving transistors on a backplane. Each pixel circuit may be electrically connected to a gate line and a data line to communicate with one or more driving circuits, such as a gate driver and a data driver, located in the non-display area.

As shown in FIG. 1, the driving circuit may be implemented as a thin film transistor (TFT) in the non-display area. This driving circuit may be referred to as a gate-in-panel (GIP). Additionally, some components, such as data driver ICs, are mounted on separate printed circuit boards and circuit films such as FPCB (flexible printed circuit board), COF (chip-on-film), TCP (tape-carrier-package), etc. It can be combined with a connection interface (pad/bump, pin, etc.) placed in the non-display area.

The foldable display device 1000 may include various additional elements for generating various signals or driving pixels within the display area. Additional elements for driving the pixel may include an inverter circuit, a multiplexer, an electrostatic discharge circuit, etc. The display device 1000 may also include additional elements related to functions other than pixel driving. For example, the display device 1000 may include additional elements that provide a touch detection function, a user authentication function (eg, fingerprint recognition), a multi-level pressure detection function, a tactile feedback function, etc. The above-mentioned additional elements may be located in the non-display area and/or in an external circuit connected to the connection interface.

Various parts of the display device 1000 may be bent along the bend line FL. The curved line FL may extend horizontally (e.g., the Based on the design, it can be bent in any combination of horizontal, vertical, and diagonal directions.

As mentioned, one or more edges of the display device 1000 may be bent away from the central portion 1000-1 along the curved line FL. Although the curved line FL is shown to be located close to the edge of the display device 1000, the curved line FL extends across the central portion 1000-1 or extends across the display device 1000. It may extend diagonally from one or more corners of .

In some embodiments, the curved portion 1000-2 of the foldable display device 100 may include a display area capable of displaying an image. This display area is hereinafter referred to as an auxiliary display area. That is, the curved line FL may be placed within the display area so that at least some pixels of the display area are included in the curved portion 1000-2.

Figure 2 is a cross-sectional view showing a portion of the display panel included in the display device of this specification.

The display device `1000 may be composed of a display panel 100 that displays an image and various mechanical parts (frame, case, etc.). In the following, an organic light emitting display panel (Organic Light Emitting Display) will be used as an example. Describes the foldable display device and its display panel.

The organic light emitting display panel 100 includes thin film transistors 102, 104, 106, and 108, organic light emitting elements 112, 114, and 116, and various functional layers located on a base layer 101.

The base layer 101 supports various components of the organic light emitting display panel 100. The base layer 101 may be formed of a transparent insulating material, such as glass, plastic, etc. When the base layer 101 is made of plastic, it may be referred to as a plastic film or a plastic substrate. For example, the base layer 101 may be in the form of a film containing one selected from the group consisting of polyimide-based polymer, polyester-based polymer, silicone-based polymer, acrylic polymer, polyolefin-based polymer, and copolymers thereof. Among these materials, polyimide is widely used as a plastic substrate because it can be applied to high-temperature processes and can be coated. The substrate (array substrate) may be referred to as a concept including elements and functional layers formed on the base layer 101, such as a switching TFT, a driving TFT connected to the switching TFT, an organic light emitting device connected to the driving TFT, a protective film, etc. do.

A buffer layer may be located on the base layer 101. The buffer layer is a functional layer to protect the thin film transistor (TFT) from impurities such as alkali ions leaking from the base layer 101 or lower layers. The buffer layer may be made of silicon oxide (SiOx), silicon nitride (SiNx), or multiple layers thereof.

A thin film transistor is placed on the base layer 101 or buffer layer. The thin film transistor may have a semiconductor layer 102, a gate insulating film 103, a gate electrode 104, an interlayer insulating film 105, and source and drain electrodes 106 and 108 arranged sequentially. The semiconductor layer 102 is located on the base layer 101 or buffer layer. The semiconductor layer 102 may be made of polysilicon (p-Si), in which case a predetermined region may be doped with impurities. Additionally, the semiconductor layer 102 may be made of amorphous silicon (a-Si), or may be made of various organic semiconductor materials such as pentacene. Furthermore, the semiconductor layer 102 may be made of oxide. The gate insulating film 103 may be formed of an insulating inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx), and may also be formed of an insulating organic material. The gate electrode 104 is made of various conductive materials, such as magnesium (Mg), aluminum (Al), nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W), gold (Au), or alloys thereof. etc. can be formed.

The interlayer insulating film 105 may be formed of an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), and may also be formed of an insulating organic material. By selectively removing the interlayer insulating film 105 and the gate insulating film 103, a contact hole exposing the source and drain regions may be formed.

The source and drain electrodes 106 and 108 are formed of an electrode material on the interlayer insulating film 105 in a single-layer or multi-layer shape.

A planarization layer 107 may be located on the thin film transistor. The planarization layer 107 protects the thin film transistor and planarizes its top. The planarization layer 107 may be formed in various forms, and may be formed of an organic insulating film such as BCB (Benzocyclobutene) or acryl, or an inorganic insulating film such as silicon nitride (SiNx) or silicon oxide (SiOx). Various modifications are possible, such as being formed as a single layer or consisting of double or multiple layers.

The organic light emitting device may have a first electrode 112, an organic light emitting layer 114, and a second electrode 116 arranged sequentially. That is, the organic light emitting device includes a first electrode 112 formed on the planarization layer 107, an organic light emitting layer 114 located on the first electrode 112, and a second electrode located on the organic light emitting layer 114 ( 116).

The first electrode 112 is electrically connected to the drain electrode 108 of the driving thin film transistor through a contact hole. When the organic light emitting display panel 100 is a top emission type, the first electrode 112 may be made of an opaque conductive material with high reflectivity. For example, the first electrode 112 may be formed of silver (Ag), aluminum (Al), gold (Au), molybdenum (Mo), tungsten (W), chromium (Cr), or an alloy thereof. .

The bank 110 is formed in the remaining area excluding the light emitting area. Accordingly, the bank 110 has a bank hole that exposes the first electrode 112 corresponding to the light emitting area. The bank 110 may be made of an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx), or an organic insulating material such as BCB, acrylic resin, or imide resin.

The organic light emitting layer 114 is located on the first electrode 112 exposed by the bank 110 . The organic light-emitting layer 114 may include a light-emitting layer, an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer. The organic light-emitting layer may be composed of a single light-emitting layer structure that emits a single light, or may be composed of a plurality of light-emitting layers that emit white light.

The second electrode 116 is located on the organic light emitting layer 114. When the organic light emitting display panel 100 is a top emission type, the second electrode 116 is a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). By being formed of a material, the light generated in the organic light emitting layer 114 is emitted to the upper part of the second electrode 116.

A protective layer 118 and an encapsulation layer 120 are positioned on the second electrode 116. The protective layer 118 and the encapsulation layer 120 prevent oxygen and moisture from penetrating from the outside to prevent oxidation of the light emitting material and electrode material. When an organic light-emitting device is exposed to moisture or oxygen, pixel shrinkage, which reduces the light-emitting area, may occur, or dark spots may appear within the light-emitting area. The passivation layer and/or the encapsulation layer are composed of an inorganic film made of glass, metal, aluminum oxide (AlOx), or silicon (Si)-based material, or are composed of an organic film and an inorganic film alternately. It may also be a layered structure. The inorganic film serves to block the penetration of moisture or oxygen, and the organic film serves to flatten the surface of the inorganic film. The reason for forming the encapsulation layer with multiple thin film layers is to make the movement path of moisture or oxygen longer and more complicated than a single layer, making it difficult for moisture/oxygen to penetrate into the organic light emitting device.

The organic light emitting display panel 100 may have a touch panel 150 formed on the encapsulation layer 120 to detect a user's touch input. If necessary, an independent layer equipped with touch sensing electrodes and/or other components associated with touch input sensing may be provided inside the display panel 100. The touch sensing electrode (e.g., touch driving/sensing electrode) is made of indium tin oxide, carbon-based materials such as graphene, carbon nanotubes, conductive polymers, hybrid materials made of mixtures of various conductive/non-conductive materials, etc. It may be formed of a transparent conductive material. Additionally, a metal mesh, such as aluminum mesh or silver mesh, may be used as the touch sensing electrode.

The cover layer 180 may be used to protect the upper part of the display panel 100. The cover layer 140 may be a cover glass. A polarizing layer that controls display characteristics (e.g., external light reflection, color accuracy, luminance, etc.) may be located on one side of the cover layer 180, and as an example of an implementation, it may be located on the lower surface of the cover layer 180 as shown in FIG. 4B. A polarizing layer 170 may be coated.

In order to increase the strength and/or rigidity of a specific part of the foldable display device 1000, one or more reinforcing films may be provided under the base layer 101. The reinforcement film is attached to the side (second side) opposite to the side (first side) where the organic light emitting device is located among both sides of the base layer 101. The reinforcement film is polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethylene ether phthalate, polycarbonate, polyarylate, polyetherimide ( It can be made of a thin plastic film composed of a combination of polyether imide, polyether sulfonate, polyimide polyacrylate, and other suitable polymers. Other materials that can be used to form the reinforcement film may be thin glass, multilayer polymers, polymer films containing polymer materials in combination with nanoparticles or micro particles, etc.

3A and 3B are diagrams illustrating a foldable display device according to an embodiment of the present specification.

A foldable display device may be composed of multiple thin film layers and an adhesive that bonds them, and due to material characteristics and limitations, folding curvature, repeated folding, and/or flatness when stored for a long time in a folded state. Maintenance is important.

The foldable display device may include two or more flat areas A-1 and A-2 and a folded area F between the flat areas A-1 and A-2, as shown in FIG. 3A. and can be folded as shown in Figure 3b. The flat areas (A-1, A-2) are substantially flat areas (parts) with a very small curvature compared to the folded area (F), and may include a display area, and, if necessary, a non-display area and / Or it may further include other areas. In Figure 3a, only two flat areas are shown, but the actual product may be composed of two or more flat areas. Folding area (center bezel) Since the width is correlated with the folding radius, it can be determined based on this, and it is desirable to design it taking the encapsulation margin into consideration. The folded area F may be understood as the sum of the actual folded portion and the encapsulation margin.

The pixel matrix in the second flat area A-2 may extend continuously from the first flat area A-1. Alternatively, in FIG. 3A, the first flat region and the second flat region may be separated from each other with a folded region in between. Several parts of the first flat area and the second flat area may be electrically connected via one or more conductors laid across the folded area. The pixels of the first flat area A-1 and the pixels of the second flat area A-2 may be driven by a driving circuit (eg, gate driver, data driver, etc.) as if they were in the same matrix. At this time, the pixels of the first flat area (A-1) and the pixels of the second flat area (A-2) may be operated by the same driving circuits. For example, the N-th row pixel of the first flat area A-1 and the N-th row pixel of the second flat area A-2 may be provided to receive a gate signal from the same gate driver. Depending on the implementation, the pixels of the second flat area A-2 may be driven separately from the pixels of the first flat area A-1. That is, the pixels of the second flat area A-2 can be recognized by the driving circuit as an independent matrix separate from the pixel matrix of the flat area. In this case, the pixels of the second flat area (A-2) may receive signals from one or more separate driving circuits that are different from the driving circuit that supplies signals to the pixels of the first flat area (A-1). . Meanwhile, regardless of its shape, the second flat area A-2 may function as a secondary display area of the foldable display panel 100. Additionally, the size ratio of the first flat area (A-1) to the second flat area (A-2) is not particularly limited.

In the foldable display device 1000 that is folded (or bent) as shown in FIG. 3B, it is important that the support member 300 is designed so that excessive compressive or tensile force is not applied to the display panel 100. In addition, in order to maintain the flatness and/or quickly restore the shape of the foldable display device 1000, the shape and material of the support member 300 are also very important. Figure 3b shows an inward foldable display device, but the above-mentioned importance is the same for an outward foldable display device that folds in the opposite direction.

4A to 4C are cross-sectional views showing a foldable display device according to an embodiment of the present specification.

The foldable display device 1000 may have a structure in which a display panel 100 and a support member 300 are bonded as shown in FIG. 4A. The foldable display device 1000 includes two or more flat areas and a folded area F between the flat areas, and the folded area F has a structure with improved foldability and resilience. It can be included. The display panel 100 is a structure in which an organic light emitting diode layer (TFT/OLED), a touch panel 150, a polarizing layer 170, a cover layer 180, etc. are stacked on a flexible base layer 101 as shown in FIG. 2. And, a support member 300 may be further positioned below the display panel 100. An adhesive layer and/or the reinforcing film may be further positioned between the display panel 100 and the supporting member.

Since the folded area F is most affected by bending stress, various stress reduction structures can be applied to the display panel 100 on the folded area. To this end, some of the components in the flat area may not be present in at least a portion of the folded area (F). For example, organic light-emitting devices (eg, pixel circuits and organic light-emitting diodes) may not be disposed in the folded area F. Additionally, only a minimum number of layers may be disposed in the folded area (F). For example, in the folded area F, only a base layer, an organic layer on top of the base layer, and a cover layer on the organic layer may be disposed. Additionally, in the folded region F, there may be an additional patterned inorganic layer between the base layer and the organic layer. The inorganic layer may be a buffer layer. The patterning can be implemented through a series of etching processes. The pattern may be in the form of stripes parallel to the folding axis, and the pitch may be designed taking the folding curvature into consideration.

The support member 300 is located on one side (lower surface) of the display panel 100. For example, as shown in FIG. 4B, the support member 300 may surround the outer surface of the display panel 100 from the rear in the screen display direction. The support member 300 serves to support the display panel 100. Accordingly, the support member 300 has greater stiffness than the display panel.

If the folding and unfolding operation of the foldable display device 1000 is repeated, plastic deformation may occur in the support member 300, which may limit the folding/unfolding of the foldable display device 10. This plastic deformation problem can be reduced by reducing the thickness of the support member 300, but as the thickness of the support member 300 is reduced, the elastic restoring energy also decreases, resulting in a trade-off that takes a long time to restore the shape. A trade-off may appear.

Accordingly, the inventors designed a support member that is thin and has sufficient rigidity to support the display panel, while also exhibiting excellent resilience after deformation. Designed in this way, the support member 300 according to an embodiment of the present specification may be a multi-layer structure composed of two or more metal layers.

As shown in FIG. 4B, the support member 300 may include two or more metal layers with high stiffness and/or Young's modulus and thus have high restoring force. The metal layers 310, 320, 330, and 340 have a folded region F between the flat regions, similar to the region division of the foldable display device 1000. Additionally, one or more of the metal layers 310, 320, 330, and 340 may have opening patterns 321, 331, and 341 in the folded region F. Furthermore, the support member 300 may include a structure that can prevent image quality from being deteriorated due to the opening patterns 321, 331, and 341.

The metal layers 310, 320, 330, and 340 included in the support member 300 may all be of the same type (material) or, depending on the embodiment, may be different types of metal layers. The metal layers 310, 320, 330, and 340 may all have a yield stress of 1 GPa or more.

When an object receives an external force, strain and stress increase in proportion to the force up to a certain point, while when the force is removed, the strain and stress decrease linearly, returning to the initial shape before deformation. However, if the magnitude of the force exceeds a certain value, the object cannot be restored to its initial shape even if the force is removed, and some degree of permanent deformation is maintained. And from this point on, strain and stress no longer maintain a linear relationship, but also exhibit rapid strain rates and ultimately lead to fracture. Yield stress refers to the stress value that serves as a standard for distinguishing these distinct object behaviors. In other words, below the yield stress, strain and stress maintain a linear relationship, and no permanent deformation remains when the force is removed. However, at forces exceeding the yield stress, strain and stress exhibit a significant non-linear relationship, and the object exhibits permanent deformation even when the force is removed.

4B and 4C, in the support member 300 composed of four layers, starting from the metal layer closest to the display panel 100, the first metal layer 310, the second metal layer 320, and the third metal are sequentially formed. Layer 330, referred to as fourth metal layer 340. 4B and 4C, the second metal layer 320, third metal layer 330, and fourth metal layer 340 include opening patterns 321, 331, and 341 in the folded region F. .

The opening patterns 321, 331, and 341 included in the second to fourth metal layers 320, 330, and 340 reduce stress when the support member 300 is folded. The shape and arrangement of the opening patterns in each metal layer are described in more detail in FIGS. 5 and 6. The opening patterns 321, 331, and 341 may be slits of various shapes such as rectangles, diamonds, and ellipses, and the widths (w2, w3, and w4) may become wider as they go downward. (w2<w3<w4) In other words, the metal layer farther from the display panel has a wider opening pattern.

At least one metal layer included in the support member 300 does not have an opening pattern. 4B and 4C, there is no opening pattern in the first metal layer 310. The reason why the support member 300 includes a metal layer without an opening pattern is to make the brightness of the display panel uniform. As a result of the test, when the foldable display device was unfolded, brightness unevenness such as stains appeared in the folded area, and this was analyzed as the main cause of temperature unevenness due to the opening pattern in the folded area. It was also confirmed that the above-mentioned non-uniformity can be prevented by placing a metal filler without an opening pattern between the display panel 100 and the metal layer with an opening pattern. Accordingly, in the support member 300 according to an embodiment of the present specification, one or more metal layers 310 without an opening pattern are disposed closest to the display panel 100. That is, one or more metal layers without an opening pattern are located between the display panel 100 and the metal layer with an opening pattern.

Meanwhile, the metal layers 310, 320, 330, and 340 included in the support member 300 may have different thicknesses, and the thicknesses (t1, t2, t3, and t4) may become thicker downward. . (t1<t2<t3<t4) That is, the farther away the metal layer is from the display panel 100, the thicker it may be. In the illustrated example of FIG. 4B, the thickness t1 of the first metal layer 310 is the thinnest, and the thickness t4 of the fourth metal layer 340 is the thickest.

The opening pattern is formed in the folded area (F). However, depending on the embodiment, the opening pattern may be provided outside the folded area, that is, in the flat area.

At least some of the opening patterns 321, 331, and 341 may be filled with one or more of polyurethane (PU), thermoplastic polyurethane (TPU), polyacrylate, rubber, and silicon (Si).

5A to 5D are diagrams illustrating the shape of an opening pattern applied to a support member according to an embodiment of the present specification.

The opening pattern is provided to improve the folding and restoration characteristics of the metal layer forming the support member. The opening pattern is formed in the folded area (F). However, depending on the embodiment, the opening pattern may be provided outside the folded area, that is, in the flat area.

In FIGS. 5A to 5D, only the second metal layer 320 and the opening pattern 321 therein are shown for convenience of explanation. However, the opening pattern 321 is similar to the third metal layer 330 and the fourth metal layer 340. ) can also be applied. Also, although the folded area F is shown in FIGS. 5A to 5D as being located in a specific part of the metal layer 320, the location of the folded area F is not limited thereto. Additionally, two or more folded regions (F) may be defined.

As shown in FIG. 5A, the opening pattern 321a may have a rectangular shape. At this time, the opening pattern 321a may have a shape extending in a direction parallel to the fold line (fold axis). That is, the long axis of the opening pattern 321a may be parallel to the direction of the fold line (fold axis). The rectangular shape may have a specific length (L1) and be spaced apart by a specific distance (D1) on the same line.

Additionally, as shown in FIGS. 5B and 5C, each of the opening patterns 321b may have a diamond shape. At this time, the opening patterns 321b and 321c may have a shape extending in a direction parallel to the fold line (fold axis). That is, the long axes of the opening patterns 321b and 321c may be parallel to the direction of the fold line (fold axis). The rhombus (diamond) shape may have a specific length (L2, L3) and be spaced apart by a specific distance (D2, D3) on the same line. Meanwhile, the diamond shape arranged in the same row may be placed side by side with the diamond shape arranged in an adjacent row (FIG. 5B), or may be placed misaligned (FIG. 5C).

As shown in FIG. 5D, the opening pattern 321d may have an oval shape with a constant minor axis length, or a shape in which semicircles are joined to both ends of a rectangle. At this time, the opening pattern 321d may have a shape extending in a direction parallel to the fold line (fold axis). That is, the long axis of the opening pattern 321d may be parallel to the direction of the fold line (fold axis). The oval (or rectangular with rounded corners) shape may have a specific length (L4) and be spaced apart by a specific distance (D4) on the same line.

5A to 5D, the opening patterns 321a, 321b, 321c, and 321d are illustrated as being rectangular, diamond, or elliptical, but the shape of the opening pattern is not limited thereto. For example, the opening pattern may be circular, oval, square, trapezoidal, or other shapes. Also, only one opening pattern shape cannot be provided in one metal layer. In other words, opening patterns of various shapes may be provided in one metal layer.

6A to 6D are diagrams illustrating the arrangement of opening patterns applied to a support member according to an embodiment of the present specification.

In FIGS. 6A to 6D, for convenience of explanation, only the second metal layer 320 and the opening pattern 321 therein are shown among the metal layers included in the support member, but the opening pattern 321 is a third metal layer ( 330) and the fourth metal layer 340. Also, although the folded area F is shown in FIGS. 6A to 6D as being located in a specific part of the metal layer 320, the location of the folded area F is not limited thereto.

As shown in FIGS. 6A and 6B, a folded region F is defined in the metal layer 320, and the folded region F may be divided into a central portion CN and edge portions ED1 and ED2. At this time, the opening patterns 321 formed in the folded area F have the same size and the distances between them are different. (pitch variable)

The folded area F is divided into a central part CN, a first edge part ED1, and a second edge part ED2, and the opening pattern 321 is spaced apart from the first edge part ED1 in the folding direction. It has a distance d1, a second separation distance d2 at the center CN, and a third separation distance d3 at the second edge ED2, which is larger than the second distance and smaller than the first distance. That is, the distance between the opening patterns 321 may decrease from the edge to the center of the folded area F. Damage to the display panel may occur as stress is concentrated at the point where the curvature of the foldable display device begins (i.e., the first edge ED1). In the support member of the present specification, the folded area (F) of the metal layer 320 ), the radius of curvature at the folding start point can be increased and the stress concentration can be alleviated by adjusting the distance between the opening patterns 321 formed. Accordingly, damage to the display panel is minimized or prevented.

As shown in FIGS. 6C and 6D, a folded region F is defined in the metal layer 320, and the folded region F may be divided into a central portion CN and edge portions ED1 and ED2. At this time, the opening patterns 321 formed in the folded area F are arranged at the same distance apart and have different sizes. (size variable)

The folded area (F) is divided into a central part (CN), a first edge part (ED1), and a second edge part (ED2), and the opening pattern 321 has a first width from the first edge part ED1 in the folding direction. (w1), a second width (w2) at the central portion (CN), and a third width (w3) larger than the first width and smaller than the second width at the second edge portion (ED2). That is, the size (width) of the opening pattern 321 may gradually increase from the edge to the center of the folded area F. In the support member of the present specification, the size of the opening pattern 321 formed in the folded area F of the metal layer 320 is adjusted, thereby increasing the radius of curvature at the folding start point and relieving stress concentration. Accordingly, damage to the display panel is minimized or prevented.

Changes in arrangement and size of the opening patterns illustrated in FIGS. 6A and 6B and 6C and 6D may be applied together to one metal layer.

Although embodiments of the present specification have been described in detail with reference to the attached drawings, the present specification is not necessarily limited to these embodiments, and various modifications may be made without departing from the technical spirit thereof. Accordingly, the embodiments disclosed in this specification are not intended to limit the technical idea of the present invention, but rather to explain it, and the scope of the technical idea of the present invention is not limited by these embodiments. Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and can be technically linked and driven in various ways by those skilled in the art, and each embodiment can be performed independently of each other or together in a related relationship. It may be implemented. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

Claims (31)

a display panel including a display area and a non-display area disposed around the display area;
The display panel has at least two fold lines,
The at least two fold lines are parallel to each other,
One of the at least two fold lines is located in the display area, and the other one of the at least two fold lines is located in the non-display area,
A support member supporting the display panel on one side of the display panel,
The support member has a multi-layer structure including a first layer disposed below the display panel, a second layer disposed below the first layer, and a third layer disposed below the second layer,
The second layer of the support member includes a plurality of holes in an area overlapping with one of the at least two fold lines located in the display area,
The third layer includes an opening in an area that overlaps an area of the second layer where the plurality of holes are formed. delete According to paragraph 1,
A driving circuit is disposed in the non-display area,
The driving circuit is a foldable display device including at least one of a gate drive, electrostatic discharge circuit (ESD), or multiplexer (MUX). According to paragraph 3,
The multiplexer is a foldable display device positioned between a fold line located in the display area and a fold line located in the non-display area. According to paragraph 3,
The electrostatic discharge circuit is composed of a plurality,
A foldable display device wherein at least one of the plurality of electrostatic discharge circuits is located between a fold line located in the display area and a fold line located in the non-display area. According to paragraph 3,
A foldable display device in which a fold line located in the display area overlaps a portion of the gate driver located in the non-display area. According to paragraph 1,
A foldable display device in which pixels disposed in the display area each include a thin film transistor composed of a gate electrode, a source electrode, and a drain electrode. In clause 7,
A foldable display device further comprising a planarization layer on the source electrode and the drain electrode. According to clause 8,
Further comprising an anode on the planarization layer,
The anode is a foldable display device connected to the drain electrode. According to clause 9,
a bank on the anode exposing a portion of the anode;
an organic light-emitting layer on the anode exposed by the bank; and
A foldable display device further comprising a cathode on the organic light emitting layer. According to clause 10,
a protective layer on the cathode; and
A foldable display device further comprising an encapsulation layer on the protective layer. According to clause 11,
The protective layer is a foldable display device having any one of an inorganic film structure made of glass, metal, aluminum oxide (AlOx), or silicon (Si)-based material, or a structure in which organic films and inorganic films are alternately stacked. According to clause 11,
The encapsulation layer is a foldable display device having either an inorganic film structure made of glass, metal, aluminum oxide (AlOx), or silicon (Si)-based material, or a structure in which organic films and inorganic films are alternately stacked. According to paragraph 1,
The display area is a foldable display device having a first flat area and a second flat area based on a fold line located in the display area. According to clause 14,
The pixels in the second flat area are continuously extended from the first flat area or are separated from each other. According to clause 14,
A foldable display device in which the pixels in the first flat area and the pixels in the second flat area are operated by the same driving circuit or by separate driving circuits. According to clause 14,
A foldable display device in which the size ratio of the first flat area and the second flat area is the same or different. According to paragraph 1,
A foldable display device further comprising an adhesive layer disposed between the display panel and the support member. According to paragraph 1,
A foldable display device further comprising a reinforcement film disposed between the display panel and the support member. According to paragraph 1,
A foldable display device further comprising a window cover on an upper portion of the display panel. According to clause 14,
A foldable display device in which the support member is made of a metal material. According to clause 21,
The support member is,
the first layer made of a metal material below the display panel; and
a second layer below the first layer and made of a metal material having a plurality of holes in an area overlapping with one of the at least two fold lines;
A foldable display device in which the first layer has no hole in an area overlapping with any one of the at least two fold lines. According to clause 22,
A foldable display device in which the second layer is thicker than the first layer. According to clause 22,
The third layer is a foldable display device made of a metal material. According to clause 24,
A foldable display device in which the third layer is thicker than the second layer. According to clause 24,
The width of the opening disposed on the third layer is wider than the width of the plurality of holes disposed on the second layer. According to clause 24,
The first layer is a foldable display device that reduces screen unevenness due to a plurality of holes disposed in the second layer or openings disposed in the third layer. According to paragraph 1,
The plurality of holes are slits extending in a direction parallel to at least one of the two or more fold lines. According to paragraph 1,
A foldable display device in which the plurality of holes have one or more shapes selected from the group consisting of a rectangle, a diamond, an oval, and a rectangle with rounded corners. According to paragraph 1,
A foldable display device in which at least some of the plurality of holes are filled with silicon. According to clause 24,
The second layer or the third layer has a plurality of holes and openings in areas corresponding to the first flat area and the second flat area, respectively.