Flexible display device and metal plate for flexible display device

Abstract

According to an embodiment, a flexible display device includes a display panel including pixels and having a folding region, and a metal plate positioned on the back surface of the display panel. The metal plate includes a lower metal plate, an upper metal plate including a step portion, a main spacer positioned between the lower metal plate and the upper metal plate, and a sub-spacer. The sub-spacer overlaps the step portion in a plane.

Description

Technical Field

[0001] The present disclosure relates to a flexible display device and a metal plate for a flexible display device, and more specifically, to a flexible display device that does not cause problems due to folding and has enhanced impact resistance, and a metal plate therefor.

Background Art

[0002] A display device such as an organic light-emitting display device includes a display panel, and the display panel is manufactured by including a plurality of layers and elements on a substrate. Conventionally, glass has been used as the substrate of the display panel. However, since the glass substrate is rigid, it is difficult to distort or deform the display device. In recent years, flexible display devices using flexible substrates such as plastic, which are light and easily deformable, have been developed.

[0003] Flexible display devices can be classified into bendable display devices, foldable display devices, rollable display devices, etc., depending on their uses and forms. Such flexible display devices can be bent or folded using a flexible substrate such as plastic.

[0004] In addition, recent display devices can include a function of sensing the position of a touch when the screen is touched, and the display device can sense a touch of a hand or a touch of another pen.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An embodiment aims to provide a flexible display device with enhanced impact resistance that does not cause problems even when folded several times, and a metal plate for the flexible display device.

Means for Solving the Problems

[0006] A flexible display device according to an embodiment includes a display panel including pixels and having a folding region, and a metal plate located on the back surface of the display panel. The metal plate includes a lower metal plate, an upper metal plate including a stepped portion, and a main spacer and a sub-spacer located between the lower metal plate and the upper metal plate. The sub-spacer can overlap with the stepped portion in a plane.

[0007] The upper metal plate includes a first portion having a thin thickness and a second portion having a thicker thickness than the first portion. The main spacer can overlap with the second portion in a plane.

[0008] Air can be located between the lower metal plate and the upper metal plate and around the main spacer and the sub-spacer.

[0009] The metal plate further includes a sealant formed along the outer contour, and the sealant can seal the space between the upper metal plate and the lower metal plate.

[0010] The sealant further includes a plurality of conductive spacers, and the plurality of conductive spacers can be in contact with the upper metal plate and the lower metal plate.

[0011] A filler that plays a buffering role can be located in the space sealed by the sealant.

[0012] The metal plate also has a folding region in a portion corresponding to the folding region of the display panel, and a mesh pattern portion having a plurality of openings (apertures) can be located in the folding region of the metal plate.

[0013] The main spacer and the sub-spacer can be located at positions that do not overlap with the plurality of openings in the mesh pattern portion.

[0014] The main spacer, the secondary spacer, and the stepped portion can be formed over the entire area of the metal plate.

[0015] The metal plate also has a folding area in a portion corresponding to the folding area of the display panel, and the main spacer, the secondary spacer, and the stepped portion can be located in the folding area.

[0016] The upper metal plate is formed of a metal plate having a plate-like structure and an insulating layer located on one surface of the metal plate, and the stepped portion can be located between adjacent insulating layers.

[0017] It may further include a cover window located in front of the display panel; and a protective layer or a cushion layer located between the display panel and the metal plate.

[0018] A metal plate according to an embodiment includes a lower metal plate, an upper metal plate including a stepped portion, and a main spacer and a secondary spacer located on the lower metal plate. The secondary spacer overlaps the stepped portion in a plane. The upper metal plate includes a first portion having a small thickness and a second portion having a greater thickness than the first portion, and the main spacer overlaps the second portion in a plane.

[0019] Air can be located between the lower metal plate and the upper metal plate and around the main spacer and the secondary spacer.

[0020] The metal plate further includes a sealant formed along the outer periphery, and the sealant can seal the space between the upper metal plate and the lower metal plate.

[0021] The sealant further includes a plurality of conductive spacers, and the plurality of conductive spacers can contact the upper metal plate and the lower metal plate.

[0022] In the space sealed by the sealant, a filler that serves as a buffer can be located.

[0023] The main spacer and the sub-spacer can be located at positions that do not overlap with the plurality of openings in the mesh pattern portion.

[0024] The upper metal plate is formed of a metal plate having a plate-like structure and an insulating layer located on one surface of the metal plate, and the step portion can be located between adjacent insulating layers.

Advantages of the Invention

[0025] According to the embodiment, a plurality of spacers are formed in the metal plate, and some of the plurality of spacers are formed so as not to contact the upper metal plate, having a buffering effect against impact and enhancing the impact resistance. In order to complement the impact resistance with the metal plate, for the portion excluding the metal plate from the flexible display device, the deformation rate can be increased by adopting materials and physical properties without considering the impact resistance. As a result, it is possible to eliminate or reduce the bending deformation that may occur in the folding region of the flexible display device.

Brief Description of the Drawings

[0026]

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Best Mode for Carrying Out the Invention

[0027] Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them in the technical field to which the present invention pertains. The present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0028] To clearly explain the present invention, parts not related to the explanation are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0029] Also, the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, the thickness is enlarged to clearly represent a plurality of layers and regions. And, in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

[0030] Also, when a part such as a layer, film, region, plate, or component is "above" or "on" another part, this includes not only the case where it is directly above the other part but also the case where there is another part in between. Conversely, when a part is "directly above" another part, it means that there is no other part in between. Also, being "above" or "on" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" or "on" in the opposite direction of gravity.

[0031] Also, throughout the specification, when a part "includes" a certain component, it means that, unless otherwise stated to the contrary, it does not exclude other components but can further include other components.

[0032] Also, throughout the specification, "on a plane" means when the target part is viewed from above, and "in a cross-section" means when the cross-section obtained by vertically cutting the target part is viewed from the side.

[0033] Also, throughout the specification, "connected" includes not only the case where two or more components are directly connected, but also the case where two or more components are indirectly connected through other components, physically connected, or electrically connected. It can also include the connection of each part that is called by different names according to its position and function but is substantially integrated with each other.

[0034] Also, throughout this specification, when a part such as a wiring, layer, film, region, plate, or component "extends in the first direction or the second direction", it does not only mean a straight-line shape that extends straight in that direction, but also includes a structure that extends overall along the first direction or the second direction and includes a structure that bends at a part, has a zigzag structure, or extends while including a curved structure.

[0035] In addition, electronic devices including the display device, display panel, etc. described in this specification (e.g., mobile phones, TVs, monitors, notebook computers, etc.), and electronic devices including the display device, display panel, etc. manufactured by the manufacturing method described in this specification are not excluded from the scope of rights of this specification.

[0036] Hereinafter, the overall structure of a flexible display device according to an embodiment will be described with reference to FIG. 1.

[0037] FIG. 1 is a perspective view schematically showing a flexible display device according to an embodiment.

[0038] A flexible display device 1000 according to an embodiment is a device for displaying videos and still images, and can be used not only for portable electronic devices such as mobile phones, smart phones, tablet personal computers, mobile communication terminals, electronic notebooks, electronic books, portable multimedia players (PMPs), navigation devices, and ultra-mobile personal computers (UMPCs), but also as a display screen for various products such as TVs, notebook personal computers, monitors, billboards, and the internet of things (IOT). In addition, the flexible display device 1000 according to an embodiment can be used for wearable devices such as smart watches, watch phones, glasses-type displays, and head-mounted displays (HMDs). Further, the flexible display device 1000 according to an embodiment can be used as an instrument panel of an automobile, and a center fascia of an automobile, or a center information display (CID) arranged on a dashboard, a room mirror display replacing a side mirror of an automobile, and a display arranged on the back of a front seat as an entertainment for a rear seat of an automobile.

[0039] Referring to FIG. 1, the flexible display device 1000 can display an image toward a third direction (DR3) on a display surface parallel to each of a first direction (DR1) and a second direction (DR2). The display surface on which the image is displayed can correspond to the front surface of the flexible display device 1000, and the image can include not only dynamic images but also still images.

[0040] In this embodiment, based on the direction in which the image is displayed, the front surface (or upper surface) and the back surface (or lower surface) of each member are defined. The front surface and the back surface face each other in the third direction (DR3), and the normal directions of the front surface and the back surface can be parallel to the third direction (DR3). The separation distance in the third direction (DR3) between the front surface and the back surface can correspond to the thickness of the display panel (DP) in the third direction (DR3).

[0041] The flexible display device 1000 according to one embodiment can sense an input of a user applied from the outside. The input of the user can include various forms of external inputs such as a part of the user's body, light, heat, or pressure. In one embodiment, the input of the user may be an input by the user's hand applied to the front surface or an input by a pen such as a stylus used by the user, and the present invention is not limited thereto. Further, the flexible display device 1000 can also sense an input of the user applied to the side surface or the back surface of the flexible display device 1000 according to the structure of the flexible display device 1000.

[0042] In one embodiment, the flexible display device 1000 can include a display area (DA) and a peripheral area (PA; hereinafter referred to as a non-display area). The display area (DA) is an area where an image is displayed and may also be an area where an external input is sensed. The display area (DA) may be an area where a plurality of pixels described later are arranged.

[0043] The display area (DA) can include a first display area (DA1) and a second display area (see DA2 in FIG. 2).

[0044] The first display area (DA1) is formed with a plurality of light-emitting diodes and a plurality of pixel circuit portions that generate and transmit a light-emitting current to each of the plurality of light-emitting diodes. Here, one light-emitting diode and one pixel circuit portion are referred to as a pixel (PX). In the first display area (DA1), one pixel circuit portion and one light-emitting diode are formed in a one-to-one correspondence.

[0045] Also, the first display area (DA1) can be divided into a first - 1 display area (DA1 - 1), a first - 2 display area (DA1 - 2), and a folding area (FA). The first - 1 display area (DA1 - 1) and the first - 2 display area (DA1 - 2) can be located on the left side and the right side respectively with respect to (or centered on) the folding axis (FAX), and a folding area (FA) can be located between the first - 1 display area (DA1 - 1) and the first - 2 display area (DA1 - 2). Here, when folded outward with respect to the folding axis (FAX), the first - 1 display area (DA1 - 1) and the first - 2 display area (DA1 - 2) are located on both sides in the third direction (DR3) and can display images in both directions. Also, when folded inward with respect to the folding axis (FAX), the first - 1 display area (DA1 - 1) and the first - 2 display area (DA1 - 2) may not be visible from the outside.

[0046] On the other hand, depending on the embodiment, the display area (DA) can further include a second display area (see DA2 in FIG. 2), and such an embodiment will be described through FIG. 2.

[0047] In FIG. 2, the planar structure of a display panel (DP) that can be included in a flexible display device 1000 according to another embodiment is described.

[0048] FIG. 2 is a plan view showing a flexible display panel according to another embodiment.

[0049] The display panel (DP) included in the flexible display device 1000 also has a display area (DA) located on the front surface. The display area (DA) is roughly divided into a first display area (DA1; hereinafter referred to as the main display area) and a second display area (DA2; hereinafter referred to as the component area).

[0050] The first display area (DA1) is formed with a plurality of light-emitting diodes and a plurality of pixel circuit units that generate and transmit a light-emitting current to each of the plurality of light-emitting diodes. Here, one light-emitting diode and one pixel circuit unit are referred to as a pixel (PX). In the first display area (DA1), one pixel circuit unit and one light-emitting diode are formed in a one-to-one correspondence.

[0051] The second display area (DA2) can include a light transmission area and can additionally include pixels for displaying an image. The second display area (DA2) may be an area that at least partially overlaps with optical elements such as a camera and a light sensor. FIG. 2 shows that the second display area (DA2) is provided in a circular shape on the left side of the flexible display device 1000, but the present invention is not limited thereto. The second display area (DA2) can be provided in various numbers and shapes according to the number and shape of the optical elements.

[0052] The flexible display device 1000 can receive external signals necessary for the optical elements or provide signals output from the optical elements to the outside through the second display area (DA2). In one embodiment, by providing the second display area (DA2) to overlap with the light transmission area, the area of the peripheral area (PA) for forming the light transmission area can be reduced.

[0053] Depending on the embodiment, a boundary area can be located between the first display area (DA1) and the second display area (DA2).

[0054] Outside the display area (DA), a peripheral area (PA) can be further located. In the embodiment of FIG. 2, the second display area (DA2) is surrounded by the first display area (DA1), and there is a possibility that the area of the display area (DA) is not reduced by the second display area (DA2) and the area of the peripheral area (PA) is not increased.

[0055] Referring to FIGS. 1 and 2, in one embodiment, the flexible display device 1000 may be a foldable flexible display device. The flexible display device 1000 can be folded outward or inward with respect to the folding axis (FAX). When folded outward with respect to the folding axis (FAX), the display surfaces of the flexible display device 1000 are respectively located outside in the third direction (DR3), and images can be displayed in both directions. When folded inward with respect to the folding axis (FAX), the display surface may not be visible from the outside.

[0056] On the other hand, in FIG. 2, a peripheral area (PA) is also shown outside the display area (DA), and it is also shown that a driving unit 50 is formed in the peripheral area (PA). The peripheral area (PA) can be divided into a region where the display area (DA) is located outside, the driving unit 50, the connection wiring, and the bending area. Depending on the embodiment, the portion of the display panel (DP) where the driving unit 50 is located is folded to the back surface, and after the driving unit 50 is positioned behind the display area (DA), the flexible display device 1000 can be completed.

[0057] In the embodiment of FIG. 2, the driving unit 50 is shown to be located in the peripheral area (PA) on the first direction (DR1) side of the display area (DA), and the driving unit 50 extends in a direction parallel to the folding axis (FAX), but the position of the driving unit 50 can be changed in various ways.

[0058] Hereinafter, through FIG. 3, the overall cross-sectional structure of the flexible display device 1000 according to an embodiment will be described.

[0059] FIG. 3 is a cross-sectional view showing a flexible display device according to an embodiment.

[0060] According to an embodiment, in a flexible display device 1000, based on a display panel (DP), a protection layer (PF), a cushion layer (CU), and a metal plate (MP) are located on the back surface thereof, and a polarizing plate (POL) and a cover window (WIN) are located on the front surface thereof.

[0061] The display panel (DP) may include a display unit where a plurality of pixels are located and an image is displayed, a touch sensor (TSP) located above (upper part) the display unit and sensing an external input, and a driving unit (refer to 50 in FIG. 2). The display panel (DP) may include a front surface including a display area (DA) and a peripheral area (PA). The display area (DA) may be an area where pixels operate according to an electrical signal and emit light. In one embodiment, among the display panel (DP), a plurality of pixels are located below the touch sensor (TSP), which is an area for displaying an image in a third direction (DR3), and at the same time, the touch sensor (TSP) is located above in the third direction (DR3) of the pixels, and an external input can be sensed.

[0062] A polarizing plate (POL) and a cover window (WIN) are located on the front surface of the display panel (DP), and the cover window (WIN) can be attached by a first adhesive layer (AD1).

[0063] The cover window (WIN) can be divided into a light-transmitting area and a blocking area, and the light-transmitting area can overlap at least part of the display area (DA) of the display panel (DP). For example, the light-transmitting area can overlap the front surface of the display area (DA) or at least part of the display area (DA). Thereby, a user can view an image through the light-transmitting area or provide an external input based on the image. However, the present invention is not limited thereto. For example, within the display area (DA), the area where an image is displayed and the area where an external input is sensed may be separated from each other.

[0064] The peripheral area (PA) of the display panel (DP) can at least partially overlap with the blocking area of the cover window (WIN). The peripheral area (PA) may be an area covered by the blocking area. The peripheral area (PA) is adjacent to the display area (DA) and can surround the display area (DA). In the peripheral area (PA), no image is displayed, and drive circuits, drive wirings, etc. for driving the display area (DA) may be arranged.

[0065] The flexible display device 1000 according to one embodiment is a foldable display device and can be a product having a large-area screen of 10 inches or more. When the cover window (WIN) is formed of glass, problems such as cracking may occur when the glass is folded, and the cover window (WIN) can be formed of a polymer film.

[0066] In one embodiment, the display panel (DP) can be assembled in a flat state in which the display area (DA) and the peripheral area (PA) face the cover window (WIN). However, the present invention is not limited thereto.

[0067] A polarizing plate (POL) can be positioned between the cover window (WIN) and the display panel (DP). After external light is incident on the display panel (DP), the polarizing plate (POL) reflects the light and provides it to the user's eyes, preventing a decrease in display quality and the visibility of the internal structure of the display panel (DP). Depending on the embodiment, the polarizing plate (POL) can be omitted.

[0068] The cover window (WIN) and the polarizing plate (POL) are attached by a first adhesive layer (AD1), and the polarizing plate (POL) may also be attached to the display panel (DP) by an adhesive layer (not shown).

[0069] On the other hand, a protective layer (PF), a cushion layer (CU), and a metal plate (MP) are sequentially positioned on the back surface of the display panel (DP), and each part may be attached by an adhesive layer (not shown).

[0070] The protective layer (PF) located on the back surface of the display panel (DP) is a layer that enhances impact resistance and is also called an impact-resistant layer. The protective layer (PF) can be formed of polyimide (PI) or polyurethane, or can be formed of a mixed resin containing polyimide (PI) or polyurethane. On the other hand, according to an embodiment, the protective layer (PF) can include a copolymer containing at least one or more resins containing urethane functional groups. Here, the urethane functional group can include -NH (Peak (3200~3300cm -1 )) and -C=O (Peak (1700~1750cm -1 ))).

[0071] The impact resistance can be increased by increasing the thickness of the protective layer (PF). However, when the thickness of the protective layer (PF) is increased in this way, there is a disadvantage that the repulsive force increases when folding the flexible display device 1000, and the reliability during folding decreases. In order to maintain the impact resistance in this way, in this embodiment, the metal plate (MP) is formed to have a structure capable of mitigating or absorbing the impact. The detailed structure of the metal plate (MP) will be described later.

[0072] A cushion layer (CU) is located on the back surface of the protective layer (PF), is formed of an elastic material, and serves to mitigate the impact applied from the back surface of the display panel (DP). Also, according to an embodiment, the cushion layer (CU) is formed in black and can also serve to prevent light from being provided to the display panel (DP) from the back surface, and to prevent the light provided from the display panel (DP) to the back surface from being reflected and provided to the front surface.

[0073] A metal plate (MP) is attached to the back surface of the cushion layer (CU). The basic role of the metal plate (MP) is to keep the flexible display device 1000 in a folded state when the flexible display device 1000 is folded with respect to the folding axis (FAX), and it can include a thin metal plate. Further, the metal plate (MP) according to this embodiment has a structure that can additionally relieve or absorb impacts.

[0074] The metal plate (MP) includes a lower metal plate (MP1), an upper metal plate (MP2), and a plurality of spacers (MPMS, MPSS). The upper metal plate (MP2) may be in contact with the main spacer (MPMS; also referred to as the first spacer), but may not be in contact with the secondary spacer (MPSS; also referred to as the second spacer). A step portion (MPV) is formed in a portion of the upper metal plate (MP2) corresponding to the secondary spacer (MPSS). As a result, when it is folded or no external impact is applied, the upper metal plate (MP2) and the secondary spacer (MPSS) can maintain a certain distance without contacting each other. The structure in which a space is formed between the secondary spacer (MPSS) and the upper metal plate (MP2) by the step portion (MPV) of the upper metal plate (MP2) is hereinafter also referred to as a buffer structure. Here, the lower metal plate (MP1) and the upper metal plate (MP2) can have a plate-like structure made of a metal material. As the metal that can be used, titanium, titanium alloy, aluminum, aluminum alloy, and various metals and their alloys can be used, and stainless metal can also be used. On the other hand, the plurality of spacers (MPMS, MPSS) can be formed of the same organic substance and can have elasticity. Since air may be located around the plurality of spacers (MPMS, MPSS) between the lower metal plate (MP1) and the upper metal plate (MP2), depending on the embodiment, a filler that plays a buffering role may be filled.

[0075] The metal plate (MP) is formed with a reduced thickness so that it can be folded without any problem, and in FIG. 3, it is shown in an enlarged view to clearly show the structure of the metal plate (MP).

[0076] The structure of the step portion (MPV) between the plurality of spacers (MPMS, MPSS) and the upper metal plate (MP2) as described above is formed not only in the folding area (FA) but also in the flat area, and can be formed over the entire area of the display panel (DP). However, unlike FIG. 3, depending on the embodiment, the structure of the upper metal plate (MP2) having the plurality of spacers (MPMS, MPSS) and the step portion (MPV) may be located only in a part of the area, for example, only in the folding area (FA), or may not be formed in a part of the display area (DA).

[0077] Since it is common to use a stylus pen for products applying a large-area screen of 10 inches or more, in the flexible display device 1000 of 10 inches or more, it is necessary to ensure the impact resistance against the stylus pen as well as the foldable characteristics. In the embodiment of FIG. 3, the impact resistance against the stylus pen is also enhanced by the metal plate (MP) so that the display panel (DP) is not damaged. That is, at least a part of the impact applied while using the stylus pen is alleviated by the buffer structure formed by the step portion (MPV) of the upper metal plate (MP2) and the sub-spacer (MPSS) in the metal plate (MP), and the impact resistance of the flexible display device 1000 is improved. That is, the metal plate (MP) alleviates not only the impact provided from below the display panel (DP) but also the impact provided from the front of the display panel (DP), such as when using the stylus pen.

[0078] In the embodiment of FIG. 3, since the impact provided from the front by the metal plate (MP) is also alleviated, there is no need to form an additional film for enhancing impact resistance on the front surface of the display panel (DP), and the materials used in the flexible display device 1000 can be adopted without considering impact resistance, so there are various advantages. For example, the bending deformation (PE) as shown in FIG. 15 can be removed or reduced.

[0079] That is, when the flexible display device 1000 is folded, a part of the flexible display device 1000 will stretch or shrink. However, if the modulus value and / or elastic force of the material constituting this part are increased, the deformation of the corresponding part will easily occur, and problems such as bending deformation (PE) caused by folding can be solved.

[0080] Hereinafter, through FIG. 4, the back structure of the metal plate (MP) included in the flexible display device 1000 according to an embodiment will be described.

[0081] FIG. 4 is a plan view of the back of the metal plate according to an embodiment.

[0082] The metal plate (MP) is attached to the back of the light-emitting display device so that when the flexible light-emitting display device is folded, it is maintained in the folded state without being unfolded again. The metal plate (MP) according to this embodiment further serves to enhance impact resistance.

[0083] In FIG. 4, the back of the metal plate (MP), that is, the back of the lower metal plate (MP1) is shown.

[0084] The lower metal plate (MP1) has a mesh pattern portion (MP-Fold) formed in a portion corresponding to the folding region (FA). The mesh pattern portion (MP-Fold) has a mesh structure including a plurality of openings and serves to reduce tensile stress and compressive stress generated by folding the metal plate (MP). Here, the plurality of openings formed in the mesh pattern portion (MP-Fold) can have various planar shapes such as circular, square, and other polygonal shapes.

[0085] On both sides of the mesh pattern portion (MP-Fold) of the lower metal plate (MP1), flat portions (MP-Flat) corresponding to the flat area are located. In the flat portion (MP-Flat) of the lower metal plate (MP1), it is formed flat as a whole, and depending on the embodiment, protrusions or openings may be formed as needed. The opening located in the flat portion (MP-Flat) may be an opening for recognizing an alignment mark.

[0086] Hereinafter, through FIG. 5, the buffer structure of the metal plate (MP) according to an embodiment will be described through an enlarged back view.

[0087] FIG. 5 is an enlarged back view of a part of the metal plate according to an embodiment.

[0088] In FIG. 5, both sides are shown centered on the boundary between the mesh pattern portion (MP-Fold) and the flat portion (MP-Flat) of the lower metal plate (MP1) of the metal plate (MP). Also, in FIG. 5, the step portion (MPV) between the spacer (MPMS, MPSS) and the upper metal plate (MP2), which is a portion hidden by the lower metal plate (MP1) and not visible, is shown by a dotted line.

[0089] As shown enlarged in FIG. 5, a main spacer (MPMS), a sub-spacer (MPSS), and a step portion (MPV) are formed in the flat portion (MP-Flat) of the lower metal plate (MP1).

[0090] The main spacers (MPMS) and the secondary spacers (MPSS) are arranged alternately and can be formed in the same number. However, depending on the embodiment, one of the main spacers (MPMS) and the secondary spacers (MPSS) may be formed in a larger number.

[0091] In the embodiment of FIG. 5, the cross-sectional size of the main spacer (MPMS) is formed larger than the cross-sectional size of the secondary spacer (MPSS). However, depending on the embodiment, the secondary spacer (MPSS) may have a larger cross-sectional size or the same cross-sectional size as each other. Also, in FIG. 5, the cross-sectional shapes of the main spacer (MPMS) and the secondary spacer (MPSS) are all shown as circular, but depending on the embodiment, they can have various cross-sectional shapes including polygons such as quadrilaterals.

[0092] On the other hand, at the portion corresponding to the secondary spacer (MPSS), a stepped portion (MPV) is formed on the upper metal plate (MP2). The stepped portion (MPV) overlaps the secondary spacer (MPSS) on a plane, and the stepped portion (MPV) is formed with an area larger than that of the secondary spacer (MPSS) so that the secondary spacer (MPSS) can be located within the stepped portion (MPV) on the plane. In the embodiment of FIG. 5, the planar shape of the stepped portion (MPV) has a square shape and a different shape from the planar shape of the secondary spacer (MPSS), but depending on the embodiment, it can have the same planar shape as the secondary spacer (MPSS). The planar shape of the stepped portion (MPV) can also have various shapes such as circular and polygonal.

[0093] On the other hand, a plurality of openings (MPOP) are further located in the mesh pattern portion (MP-Fold) of the lower metal plate (MP1) to facilitate folding of the folding region (FA).

[0094] In the mesh pattern portion (MP-Fold) of the lower metal plate (MP1), the main spacers (MPMS) and the sub-spacers (MPSS) are not formed in the portion where the plurality of openings (MPOP) are located, and are formed so that the portion where the openings (MPOP) are not located overlaps with the main spacers (MPMS) and the sub-spacers (MPSS). Depending on the embodiment, the main spacers (MPMS) and / or the sub-spacers (MPSS) may overlap with the openings (MPOP). In this case, the size of the main spacers (MPMS) and / or the sub-spacers (MPSS) is larger than the size of the openings (MPOP), and the main spacers (MPMS) and / or the sub-spacers (MPSS) can be formed so as to be supported by the lower metal plate (MP1). On the other hand, as a portion corresponding to the sub-spacers (MPSS), a stepped portion (MPV) is formed in the upper metal plate (MP2). The stepped portion (MPV) overlaps with the sub-spacers (MPSS) on a plane, the stepped portion (MPV) is formed with an area larger than that of the sub-spacers (MPSS), and the sub-spacers (MPSS) can be located within the stepped portion (MPV) on a plane.

[0095] Hereinafter, a method for manufacturing the metal plate (MP) according to the embodiment of FIG. 3 will be described with reference to FIG. 6.

[0096] FIG. 6 is a drawing showing a method for manufacturing a metal plate according to an embodiment.

[0097] Referring to FIG. 6(A), a partial region of a metal plate having a plate-like structure is etched to complete an upper metal plate (MP2) having a stepped portion (MPV). Here, the stepped portion (MPV) can be formed by dry or wet etching after forming a photoresist pattern on one surface of the metal plate. On the other hand, depending on the embodiment, a dry film (UV type Dry Film) that can form a pattern by irradiating ultraviolet rays (UV) can be used. That is, a dry film is attached onto the metal plate, irradiated with ultraviolet rays, developed, and then etched based on the pattern positioned on the metal plate, thereby completing the upper metal plate (MP2) having the stepped portion (MPV). Here, the upper metal plate (MP2) can be divided into a portion (MP2l; hereinafter referred to as the first portion) where the stepped portion (MPV) is located and the thickness is thin, and a portion (MP2h; hereinafter referred to as the second portion) where the stepped portion (MPV) does not exist and the thickness is thick.

[0098] On the other hand, referring to FIG. 6(B), a main spacer (MPMS) and a sub-spacer (MPSS) are formed using an organic substance on one surface of a lower metal plate (MP1) having a plate-like structure. The main spacer (MPMS) and the sub-spacer (MPSS) can be formed of the same organic substance. Here, the organic substance can have photosensitivity, and the main spacer (MPMS) and the sub-spacer (MPSS) can be formed by exposing and developing the organic substance. On the other hand, when the organic substance does not have photosensitivity, after laminating the organic substance, forming a photoresist pattern thereon, and then performing etching based on the formed photoresist pattern, the main spacer (MPMS) and the sub-spacer (MPSS) can be formed.

[0099] The step in FIG. 6(A) and the step in FIG. 6(B) can perform one of the two steps first, and depending on the embodiment, they can also be performed simultaneously.

[0100] Through the steps of FIG. 6(A) and FIG. 6(B), after completing the upper metal plate (MP2) having a stepped portion (MPV) and the lower metal plate (MP1) having a main spacer (MPMS) and a sub-spacer (MPSS) on one surface, these are joined together as shown in FIG. 6(C) to complete the metal plate (MP). Here, among the upper metal plate (MP2), the portion (MP2l) where the stepped portion (MPV) is located and the thickness is thin is joined so as to correspond to the sub-spacer (MPSS), and among the upper metal plate (MP2), the portion (MP2h) where the stepped portion (MPV) does not exist and the thickness is thick can be joined so as to correspond to the main spacer (MPMS).

[0101] The metal plate (MP) manufactured through FIG. 6 has a buffer structure in which a space is formed between the sub-spacer (MPSS) and the upper metal plate (MP2) by the stepped portion (MPV) of the upper metal plate (MP2), and the impact resistance is enhanced. On the other hand, air can be located around the plurality of spacers (MPMS, MPSS) between the lower metal plate (MP1) and the upper metal plate (MP2). However, depending on the embodiment, the buffer effect can also be enhanced by separately filling a filler that plays a buffer role.

[0102] Hereinafter, the structure of the metal plate (MP) according to a modified embodiment will be described with reference to FIGS. 7 to 12.

[0103] First, the structure of the embodiment of FIG. 7 will be described.

[0104] FIG. 7 is a cross-sectional view of a metal plate according to another embodiment.

[0105] In FIG. 7, an upper metal plate (MP2) having a structure different from FIGS. 3 and 6 is shown.

[0106] The upper metal plate (MP2) according to the embodiment of FIG. 7 has an insulating layer (MP2-2) containing an organic or inorganic substance formed on one surface of a metal plate (MP2-1) having a plate-like structure. As a result, the portion where the insulating layer (MP2-2) is not formed, that is, the space between adjacent insulating layers (MP2-2) corresponds to the step portion (MPV).

[0107] A method of forming the upper metal plate (MP2) as shown in FIG. 7 is to laminate an insulating material on one surface of the metal plate (MP2-1), then form a photoresist pattern, and use the photoresist pattern to etch the insulating material dry or wet to complete the insulating layer (MP2-2).

[0108] In the embodiment of FIG. 7, the main spacer (MPMS) is in contact with the insulating layer (MP2-2). Since the insulating layer (MP2-2) has a higher buffering effect than the metal plate, the impact resistance can be improved.

[0109] Hereinafter, the structures of the embodiments of FIGS. 8 and 9 will be described.

[0110] FIG. 8 is a drawing showing a method of manufacturing a metal plate according to another embodiment, and FIG. 9 is a rear view of a flexible display device according to the embodiment of FIG. 8.

[0111] The metal plate (MP) according to the embodiments of FIGS. 8(C) and 9 further includes a sealant (MPSL) formed along the outer contour of the metal plate (MP). According to the sealant (MPSL), the space between the upper metal plate (MP2) and the lower metal plate (MP1) can be sealed and enclosed to have a waterproof effect and a dustproof effect. In addition, a filler other than air can be injected into the space between the upper metal plate (MP2) and the lower metal plate (MP1) for sealing, and the impact resistance can be further improved.

[0112] On the one hand, according to the embodiment of FIG. 8(C), a plurality of conductive spacers (MPCS) are further included inside the sealant (MPSL). By contacting the upper metal plate (MP2) and the lower metal plate (MP1), the plurality of conductive spacers (MPCS) can play a role in improving the thermal conductivity and the grounding characteristics between the upper metal plate (MP2) and the lower metal plate (MP1).

[0113] First, regarding the manufacturing method of the metal plate (MP) as described above, the manufacturing method will be described with reference to FIG. 8.

[0114] Referring to FIG. 8(A), a part of the region of the metal plate having a plate-like structure is etched to complete the upper metal plate (MP2) having a stepped portion (MPV). Also in FIG. 8(A), as described in FIG. 6(A), it can be formed in various ways, and the upper metal plate (MP2) can be divided into a portion (MP2l) where the stepped portion (MPV) is located and the thickness is thin, and a portion (MP2h) where the stepped portion (MPV) does not exist and the thickness is thick.

[0115] On the other hand, referring to FIG. 8(B), a main spacer (MPMS) and a sub-spacer (MPSS) are formed on one surface of the lower metal plate (MP1) having a plate-like structure using an organic substance. The main spacer (MPMS) and the sub-spacer (MPSS) can be formed of the same organic substance. Also in FIG. 8(B), as described in FIG. 6(B), it can be formed in various ways.

[0116] The step of FIG. 8(A) and the step of FIG. 8(B) can be carried out one of the two steps first, and in some embodiments, they may be carried out simultaneously.

[0117] Through the steps of FIG. 8(A) and FIG. 8(B), after completing the upper metal plate (MP2) having a stepped portion (MPV) and the lower metal plate (MP1) having a main spacer (MPMS) and a sub-spacer (MPSS) on one side, as shown in FIG. 8(C), these are joined together. At this time, the sealant (MPSL) is positioned along the outer sides of the upper metal plate (MP2) and the lower metal plate (MP1). Referring to FIG. 9, the sealant (MPSL) is formed along the outer sides of the upper metal plate (MP2) and the lower metal plate (MP1) and can form the outer boundary of the metal plate (MP). According to the sealant (MPSL), the peripheries of the plurality of spacers (MPMS, MPSS) between the lower metal plate (MP1) and the upper metal plate (MP2) are blocked from the outside and sealed. Depending on the embodiment, air can be sealed. On the other hand, in other embodiments, before sealing with the sealant (MPSL), the peripheries of the plurality of spacers (MPMS, MPSS) can be filled with a filler that can serve as a buffer so that the filler is sealed. Since the filler has a better buffering effect than air, the impact resistance can be further improved.

[0118] Here, in the upper metal plate (MP2), the thin portion (MP2l) where the stepped portion (MPV) is located is joined so as to correspond to the sub-spacer (MPSS), and in the upper metal plate (MP2) where there is no stepped portion (MPV) and the thickness is thick (MP2h), it can be joined so as to correspond to the main spacer (MPMS).

[0119] The metal plate (MP) manufactured through FIG. 8 has a buffer structure in which a space is formed between the sub-spacer (MPSS) and the upper metal plate (MP2) by the stepped portion (MPV) of the upper metal plate (MP2), and the impact resistance is enhanced. Also, the sealant (MPSL) can seal the space between the upper metal plate (MP2) and the lower metal plate (MP1), and can have a waterproof effect and a dustproof effect, and the impact resistance can also be further improved by positioning a separate filler instead of air. Also, the thermal conductivity and grounding characteristics between the upper metal plate (MP2) and the lower metal plate (MP1) can be improved by the conductive spacer (MPCS).

[0120] In FIG. 9, the back structure of the metal plate (MP) completed through FIG. 8(C) is shown.

[0121] In FIG. 9, only the lower metal plate (MP1) and the sealant (MPSL) located on the back of the metal plate (MP) are shown.

[0122] According to FIG. 9, the sealant (MPSL) is formed along the outer contour of the metal plate (MP) and / or the lower metal plate (MP1), and is also located in the folding area (FA) to seal the inside. In FIG. 9, the width (w) of the sealant (MPSL) is shown, and it can be formed to have a width greater than 0 and less than or equal to 2 mm for sealing.

[0123] Although not shown in FIG. 9, as in FIGS. 4, 5, and 11, the folding area (FA) can have at least one mesh pattern portion, and a plurality of openings can be located in the mesh pattern portion. Also, the main spacer and the sub-spacer are located, and a stepped portion (MPV) is also formed. As in FIG. 5, the plurality of openings (MPOP) of the mesh pattern portion, the main spacer (MPMS), the sub-spacer (MPSS), and the stepped portion (MPV) may be arranged.

[0124] Hereinafter, the structure of the embodiment of FIG. 10 will be described.

[0125] FIG. 10 is a cross-sectional view of a metal plate according to another embodiment.

[0126] The metal plate (MP) in FIG. 10 has a buffer structure only in the folding area (FA), and an embodiment is shown in which in other areas (flat area), it is formed only of a metal material. Therefore, in the folding area (FA) of the metal plate (MP) according to the embodiment of FIG. 10, a lower metal plate (MP1), an upper metal plate (MP2) having a stepped portion (MPV), a main spacer (MPMS), and a sub-spacer (MPSS) are formed. On the other hand, although it is shown that a metal material is integrally formed in the flat area in the embodiment of FIG. 10, depending on the embodiment, it may also have a structure in which two upper and lower metal materials are attached. At this time, the two metal materials may be portions extending from the lower metal plate (MP1) and the upper metal plate (MP2), respectively.

[0127] Since it is also possible that the space around the plurality of spacers (MPMS, MPSS) of the metal plate (MP) according to the embodiment of FIG. 10 is sealed, between the lower metal plate (MP1) and the upper metal plate (MP2), air or a filler may be located around the plurality of spacers (MPMS, MPSS).

[0128] On the other hand, depending on the embodiment, a buffer structure may be formed only in the flat area (Flat Area), and no buffer structure may be formed in the folding area (FA). In addition, various modified embodiments are possible.

[0129] Hereinafter, the structures of the embodiments of FIGS. 11 and 12 will be described. FIG. 11 shows a modified example of the embodiment of FIG. 4.

[0130] FIG. 11 is a plan view of the back surface of a metal plate according to another embodiment, and FIG. 12 is a drawing showing a folded cross-section of a flexible display device using the metal plate of FIG. 11.

[0131] Unlike FIG. 4, the metal plate (MP) according to the embodiment of FIG. 11 includes a total of three mesh pattern portions (MP-Fold, MP-Fold’).

[0132] The mesh pattern portions (MP-Fold, MP-Fold') have a mesh structure including a plurality of openings. In the embodiment of FIG. 11, there is one main mesh pattern portion (MP-Fold) and two sub-mesh pattern portions (MP-Fold') on both sides thereof. The mesh pattern portions (MP-Fold, MP-Fold') can reduce the tensile stress and compressive stress generated by the folding of the metal plate (MP).

[0133] In the metal plate (MP) according to the embodiment of FIG. 11, flat portions (MP-Flat) are located on both sides of the two sub-mesh pattern portions (MP-Fold'), and flat portions (MP-Flat) can also be located between the main mesh pattern portion (MP-Fold) and the sub-mesh pattern portions (MP-Fold'). Depending on the embodiment, the flat portions (MP-Flat) can also be distorted. When bent more than the main mesh pattern portion (MP-Fold) and the sub-mesh pattern portions (MP-Fold'), a larger radius is formed, but it can be a portion that is relatively difficult to bend.

[0134] The main mesh pattern portion (MP-Fold) and the sub-mesh pattern portions (MP-Fold') have openings of different sizes, and the size of the mesh structure can be different. The main mesh pattern portion (MP-Fold) can be formed with a larger width than the sub-mesh pattern portions (MP-Fold').

[0135] In FIG. 11, a flexible display device including a metal plate (MP) including one main mesh pattern portion (MP-Fold) and two sub-mesh pattern portions (MP-Fold') can have a cross-sectional shape having a dumbbell shape as shown in FIG. 12 when folded.

[0136] FIG. 12 schematically shows a flexible display device 1000 including a metal plate (MP) including one main mesh pattern portion (MP-Fold) and two sub-mesh pattern portions (MP-Fold'). According to FIG. 12, it is bent by the main mesh pattern portion (MP-Fold) to have a first diameter, and a flat portion (MP-Flat) that is not bent and is located between the main mesh pattern portion (MP-Fold) and the sub-mesh pattern portion (MP-Fold') is flat or has a slightly bent portion. Then, by the sub-mesh pattern portion (MP-Fold'), it can be further bent to have a structure that is folded as a whole and has a dumbbell-like shape.

[0137] However, depending on the embodiment, it may be formed only by one mesh pattern portion as shown in FIG. 4, and other portions may additionally further include a mesh pattern portion. At this time, the additionally formed mesh pattern portion may also include one main mesh pattern portion (MP-Fold) and two sub-mesh pattern portions (MP-Fold'), or may be formed only by one mesh pattern portion. With the additionally formed mesh pattern portion, the light-emitting display device can have a plurality of positions folded in a dumbbell shape. The number of portions bent into a dumbbell shape may be two or more, and depending on the embodiment, it may be folded into a dumbbell shape at three locations.

[0138] As described above, the characteristics of the flexible display device including the metal plate (MP) having a buffer structure will be described through FIGS. 13 to 15.

[0139] FIG. 13 is a drawing showing a method of testing impact resistance.

[0140] In FIG. 13, in order to test the impact resistance of the flexible display device 1000, when dropping a chip (TIP) to test whether defective pixels are generated, the magnitudes of impacts that may occur in the flexible display device 1000 are shown in different gradations from each other.

[0141] Despite being a test of dropping a chip (TIP) as shown in FIG. 13, the flexible display device 1000 according to an embodiment can have an advantage that the metal plate (MP) has a buffer structure, can mitigate impacts, and has increased impact resistance.

[0142] In this way, since the impact resistance of the flexible display device 1000 is complemented by the metal plate (MP), in other parts excluding the metal plate (MP), there is no need to form an additional protective film to reinforce the impact resistance, and there is no need to use a material with high impact resistance for the materials used.

[0143] Hereinafter, through FIGS. 14 and 15, a flexible display device with further improved deformation characteristics will be described.

[0144] FIGS. 14 and 15 are drawings showing the characteristics of a flexible display device according to a comparative example.

[0145] In the flexible display device 1000 according to an embodiment, since the metal plate (MP) complements the impact resistance, for the part excluding the metal plate (MP) from the flexible display device 1000, materials and physical properties can be adopted without considering the impact resistance, and the deformation rate can be increased.

[0146] First, through FIG. 14, changes in the deformation amount (indicated by a dotted line) and modulus (Young's Modulus) value (indicated by a solid line) depending on the characteristics (density) of the material will be described.

[0147] Referring to FIG. 14, as the density of the material increases, the amount of deformation decreases, and it becomes difficult for the material to deform. On the other hand, the modulus value increases and the material becomes flexible. On the other hand, as the density of the material increases, the impact resistance tends to increase. Therefore, based on the density of the material, the amount of deformation and the impact resistance are in a trade-off relationship. Therefore, even if the amount of deformation is high, the impact resistance cannot be increased. Therefore, in order to reinforce the impact resistance, an additional protective film is formed on the front surface. However, in this embodiment, since the metal plate (MP) has a buffer structure, steps such as adding a protective film or an impact absorption layer on the cover window (WIN) to improve the impact resistance or adding a step of protecting the pixels in the display panel are unnecessary. For the part excluding the metal plate (MP), a material with a high amount of deformation can be used.

[0148] When a material with a high amount of deformation is used in the flexible display device 1000, the effects as shown in FIG. 15 may occur.

[0149] In FIG. 15, a flexible display device of a comparative example is shown, and a display panel (DP) and two separated substrates (SUP1, SUP2) outside thereof are shown. By folding or unfolding the support substrates (SUP1, SUP2), the display panel (DP) is also folded or unfolded. Here, the display panel (DP) of the comparative example contains a material with a low amount of deformation, and thus has ensured impact resistance by itself. The display panel (DP) of the comparative example can pass the impact resistance test by ensuring the impact resistance. However, since the amount of deformation is small, when folding and opening / unfolding (expanding) are repeated, there is a possibility that the degree of deformation is small and bending deformation (PE) may occur in the folding region (FA).

[0150] However, in the flexible display device 1000 of this embodiment, since the metal plate (MP) can ensure the impact resistance, the material contained in the display panel (DP) can ensure the amount of deformation, and bending deformation (PE) as shown in FIG. 15 does not occur or can be reduced.

[0151] As described above in detail with respect to the embodiments of the present invention, the scope of the rights of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims also belong to the scope of the rights of the present invention.

Industrial Applicability

[0152] The present invention relates to a flexible display device and a metal plate for a flexible display device.

Claims

1. A display panel including pixels and having a folding region, and a metal plate located on the back surface of the display panel, wherein the metal plate includes a lower metal plate, an upper metal plate including a stepped portion, and main spacers and sub-spacers located between the lower metal plate and the upper metal plate, wherein the sub-spacer overlaps with the stepped portion in a plane, a flexible display device.

2. The upper metal plate includes a first portion having a thin thickness and a second portion having a greater thickness than the first portion, wherein the main spacer overlaps with the second portion in a plane, the flexible display device according to claim 1.

3. The flexible display device according to claim 2, wherein air is located between the lower metal plate and the upper metal plate, and around the main spacer and the sub-spacer.

4. The metal plate further includes a sealant formed along the outer contour, wherein the sealant seals the space between the upper metal plate and the lower metal plate, the flexible display device according to claim 2.

5. The sealant further includes a plurality of conductive spacers, wherein the plurality of conductive spacers are in contact with the upper metal plate and the lower metal plate, the flexible display device according to claim 4.

6. A filler for buffering is located in the space sealed by the sealant, the flexible display device according to claim 4.

7. The metal plate also has a folding region in a portion corresponding to the folding region of the display panel, wherein a mesh pattern portion having a plurality of openings is located in the folding region of the metal plate, the flexible display device according to claim 2.

8. The main spacer and the sub-spacer are located at positions that do not overlap with the plurality of openings in the mesh pattern portion, the flexible display device according to claim 7.

9. The main spacer, the sub-spacer, and the stepped portion are formed over the entire area of the metal plate, the flexible display device according to claim 2.

10. The metal plate also has a folding region in a portion corresponding to the folding region of the display panel, wherein the main spacer, the sub-spacer, and the stepped portion are located in the folding region, the flexible display device according to claim 2.

11. The upper metal plate is formed of a metal plate having a plate-like structure and an insulating layer located on one surface of the metal plate. The step portion is the flexible display device according to claim 2, which is located between adjacent insulating layers.

12. A cover window located in front of the display panel; and The flexible display device according to claim 2, further including a protective layer or a cushion layer located between the display panel and the metal plate.

13. A lower metal plate, An upper metal plate including a step portion, and Including a main spacer and a sub-spacer located on the lower metal plate, The sub-spacer overlaps with the step portion in a plane, The upper metal plate includes a first portion having a thin thickness and a second portion having a greater thickness than the first portion, The main spacer is a metal plate that overlaps with the second portion in a plane.

14. The metal plate according to claim 13, which is between the lower metal plate and the upper metal plate, and air is located around the main spacer and the sub-spacer.

15. The metal plate further includes a sealant formed along the outer contour, The sealant is the metal plate according to claim 13, which seals the space between the upper metal plate and the lower metal plate.

16. The sealant further includes a plurality of conductive spacers, The plurality of conductive spacers are the metal plate according to claim 15, which are in contact with the upper metal plate and the lower metal plate.

17. In the space sealed by the sealant, there is a filler that serves as a buffer, which is the metal plate according to claim 15.

18. In the folding region of the metal plate, there is a mesh pattern portion in which a plurality of openings are formed, which is the metal plate according to claim 13.

19. The main spacer and the sub-spacer are located at positions that do not overlap with the plurality of openings in the mesh pattern portion, which is the metal plate according to claim 18.

20. The upper metal plate is formed of a metal plate having a plate-like structure and an insulating layer located on one surface of the metal plate, The step portion is the metal plate according to claim 13, which is located between adjacent insulating layers.

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