Folding display device

Abstract

To provide a foldable display device capable of solving problems of cracks and moisture permeation of a pad due to floating of a resin.SOLUTION: An embodiment of the present disclosure can provide a foldable display device that includes: a base substrate including a display area, a non-display area surrounding the display area and having a plurality of pads disposed on one side or both sides, and a folding area overlapping the display area and a part of the non-display area; a light emitting element disposed in the display area of the base substrate; and a cover window disposed on the light emitting element, wherein at least one of the light emitting element and the cover window disposed in the folding area extends to the non-display area to overlap the pad.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present disclosure relate to a foldable display device. [Background technology]

[0002] BACKGROUND ART In recent years, with the advent of the information age, the field of displays that visually represent electrical information signals has been developing rapidly, and accordingly, various display devices that have excellent performance, such as being thinner, lighter, and consuming less power, have been developed.

[0003] Specific examples of such display devices include liquid crystal display devices (LCDs), plasma display panel devices (PDPs), field emission display devices (FEDs), and organic light emitting display devices (OLEDs).

[0004] Recently, foldable display devices, which are manufactured using flexible materials such as plastic instead of conventional inflexible glass substrates so that they can maintain their display performance even when bent like paper, have rapidly emerged as next-generation display devices. In addition, foldable display devices with large areas have been developed and are being used for commercial purposes and consumer demands.

[0005] However, as the size of a foldable display device increases, the length of the data line also increases, resulting in an increase in data resistance. In particular, a portrait-type foldable display device having a long vertical screen ratio has a problem of a greater increase in data resistance. Summary of the Invention [Problem to be solved by the invention]

[0006] The inventors of this specification have invented a landscape type foldable display device having a long screen ratio in the horizontal direction in order to solve the above-mentioned data line problem.

[0007] The landscape-type foldable display device may include a folding region having a vertical folding axis and non-folding regions disposed on both sides of the folding region, and a pad may be provided at the end of the folding region. That is, the pad may be disposed in a non-display region of the folding region that does not display an image. The pad may be covered with resin to prevent moisture from entering the pad from the folding region.

[0008] However, in the folding area, stress caused by bending and restoring the display panel is constantly applied, which can cause the resin to lift or fall off, resulting in problems such as reduced moisture resistance and cracks in the pads.

[0009] Therefore, we invented a foldable display device that can prevent moisture penetration without using resin by forming the edges of each component that makes up the display panel to cover the pads placed in the folding area.

[0010] An embodiment of the present disclosure can provide a foldable display device that can solve the problems of pad cracking and moisture permeation caused by resin lifting by having each component of the display panel arranged in the folding area extend from the display area to the non-display area to cover the pad.

[0011] The embodiments of the present disclosure may provide a flexible display device that can be implemented as an integrated product with simplified and unified components, since resin can be omitted.

[0012] An embodiment of the present disclosure can provide a foldable display device that can maintain a constant neutral plane that occurs when the folding area is bent by arranging the ends of each component that makes up the display panel side by side to prevent any steps from occurring.

[0013] An embodiment of the present disclosure provides a foldable display device in which the neutral plane of the folding area is positioned at the center of the display panel, thereby evenly distributing the stress acting on each component during bending and restoration, and minimizing damage to the folding area. [Means for solving the problem]

[0014] An embodiment of the present disclosure can provide a foldable display device that includes a base substrate including a display area, a non-display area surrounding the display area and having a plurality of pads arranged on one or both sides, and a folding area overlapping the display area and a portion of the non-display area; a light-emitting element arranged in the display area of ​​the base substrate; and a cover window arranged on the light-emitting element, wherein the light-emitting element and the cover window arranged in the folding area extend to the non-display area to cover the pads.

[0015] An embodiment of the present disclosure can provide a foldable display device including a base substrate including a display area, a non-display area surrounding the display area and having a plurality of pads arranged on one or both sides, and a folding area overlapping the display area and a portion of the non-display area; a thin film transistor layer arranged on the base substrate; a light-emitting element arranged on the thin film transistor layer; an adhesive layer arranged on the light-emitting element; a touch panel arranged on the adhesive layer; a polarizer arranged on the touch panel; and a cover window arranged on the light-emitting element, wherein the edges of the thin film transistor layer, light-emitting element, adhesive layer, touch panel, polarizer, and cover window located in the folding area are arranged side by side, and no steps are formed.

[0016] According to an embodiment of the present disclosure, a foldable display device can be provided in which each component of the display panel arranged in the folding area extends from the display area to the non-display area to cover the pad, thereby solving the problems of cracking of the pad and moisture permeation caused by resin lifting.

[0017] According to the embodiments of the present disclosure, it is possible to provide a flexible display device that can realize an integrated product with simplified and unified components, since resin can be omitted.

[0018] According to an embodiment of the present disclosure, by arranging the ends of each component constituting the display panel side by side to form a structure without creating any steps, it is possible to provide a foldable display device that can maintain a constant neutral plane that occurs when the folding area is bent.

[0019] According to an embodiment of the present disclosure, a foldable display device can be provided in which the neutral plane of the folding area is positioned at the center of the display panel, thereby evenly distributing the stress acting on each component during bending and restoration, and minimizing damage to the folding area. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a system configuration diagram of a display device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a plan view of a display device according to an embodiment of the present disclosure. [Figure 3] 3 is a cross-sectional view of the display device shown in FIG. 2 taken along line AA'. FIG. [Figure 4] FIG. 3 is a cross-sectional view taken along line BB' shown in FIG. [Figure 5] FIG. 4 is a diagram showing the mid-plane in FIG. 3. [Figure 6] FIG. 5 is a diagram showing the mid-surface in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0021] Some embodiments of the present disclosure will be described in detail below with reference to the illustrative drawings. When adding reference numerals to components in each drawing, the same reference numerals may be used to the same components as long as they appear in different drawings. When describing the present disclosure, if a detailed description of related publicly known structures or functions is deemed to obscure the gist of the present disclosure, such a detailed description may be omitted. When terms such as "include," "have," and "perform" are used in this specification, other parts may be added unless "only" is used. When a component is expressed as a singular element, the plural may also be included unless otherwise explicitly stated.

[0022] Furthermore, when describing components of the present disclosure, terms such as first, second, A, B, (a), B, etc. are used to distinguish the components from other components, and the terms do not limit the essence, order, procedure, number, etc. of the components.

[0023] In describing the positional relationship of components, when two or more components are described as being "coupled," "coupled," or "connected," it should be understood that the two or more components may be directly "coupled," "coupled," or "connected," but that the two or more components may also be "coupled," "coupled," or "connected" through an "intervening" component. Here, the other component may be included in one or more of the two or more components that are "coupled," "coupled," or "connected" to each other.

[0024] In describing the temporal sequence of elements, methods of operation, methods of production, etc., when the temporal or chronological sequence is described using, for example, "after," "following," "after," or "before," non-consecutive sequences may also be included, unless "immediately" or "directly" is used.

[0025] On the other hand, when referring to a numerical value or its corresponding information (e.g., level, etc.) for a component, even if there is no explicit statement otherwise, the numerical value or its corresponding information can be interpreted as including an error range that may arise due to various factors (e.g., process factors, internal or external impact, noise, etc.).

[0026] Various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

[0027] FIG. 1 is a system configuration diagram of a foldable display device according to an embodiment of the present disclosure.

[0028] Referring to FIG. 1 , a display driving system of a foldable display device 100 according to an embodiment of the present disclosure may include a display panel 1 and a display driving circuit for driving the display panel 1.

[0029] The display panel 1 may include a display area AA where an image is displayed and a non-display area NA where an image is not displayed. For example, the non-display area NA may be disposed so as to partially surround the display area AA or to surround the entire surface of the display area AA. The display panel 1 may include a number of sub-pixels SP disposed on a base substrate 110 to display an image.

[0030] The display panel 1 may include a number of signal lines disposed on a base substrate 110. For example, the number of signal lines may include data lines DL, gate lines GL, driving voltage lines DVL, and the like.

[0031] Each of the data lines DL may be arranged to extend in a first direction (for example, a column direction or a row direction), and each of the gate lines GL may be arranged to extend in a direction intersecting the first direction.

[0032] The display driving circuit may include a data driving circuit 10 and a gate driving circuit 20 , and may further include a controller 30 for controlling the data driving circuit 10 and the gate driving circuit 20 .

[0033] The data driving circuit 10 can output data signals (also called data voltages) corresponding to video signals to a large number of data lines DL. The gate driving circuit 20 can generate gate signals GCS and output the gate signals GCS to a large number of gate lines GL. The controller 30 can switch input video data input from an external host 40 in accordance with the data signal DCS format used in the data driving circuit 10, and supply the switched video data to the data driving circuit 10.

[0034] The data driving circuit 10 may include one or more source driver integrated circuits. For example, each source driver integrated circuit may be connected to the display panel 1 using a tape automated bonding (TAB) method, connected to a pad of the display panel 1 using a chip on glass (COG) or chip on panel (COP) method, or implemented using a chip on film (COF) method.

[0035] The gate drive circuit 20 may be connected to the display panel 1 using a tape automated bonding (TAB) method, connected to a pad PAD of the display panel 1 using a COG or COP method, connected to the display panel 1 using a COF method, or formed in the non-display area NA of the display panel 1 as a GIP (Gate In Panel) type.

[0036] 1, GIP circuit units may be arranged on the left and right sides, respectively, of the non-display area NA, and a number of pads PADs for connection to external circuits and external power supplies that are power supply sources may be arranged on the upper and lower sides. Here, the non-display area NA in which the pads PADs are arranged can be defined as a pad area.

[0037] Referring to FIG. 1, in a foldable display device 100 according to an embodiment of the present disclosure, each sub-pixel SP may include a light-emitting element 130 and a pixel driving circuit SPC for driving the light-emitting element 130, and the pixel driving circuit SPC may include a driving transistor DRT, a scan transistor SCT, and a storage capacitor Cst.

[0038] The driving transistor DRT may control a current flowing to the light emitting element 130 to drive the light emitting element 130. The scan transistor SCT may transfer a data voltage Vdata to a second node N2, which is a gate node of the driving transistor DRT. The storage capacitor Cst may be configured to maintain a voltage for a certain period of time.

[0039] The light emitting element 130 may include a first electrode 131, a second electrode 132, and a light emitting layer 133 located between the first electrode 131 and the second electrode 132. The first electrode 131 may be a pixel electrode involved in the formation of the light emitting element 130 of each subpixel SP and may be electrically connected to a first node N1 of the driving transistor DRT. The second electrode 132 may be a common electrode involved in the formation of the light emitting element 130 of all subpixels SP and may be applied with a base voltage EVSS.

[0040] For example, the light emitting element 130 may be an organic light emitting diode (OLED), an inorganic-based light emitting diode (LED), or a quantum dot light emitting element that is a semiconductor crystal that emits light by itself.

[0041] The driving transistor DRT is a transistor for driving the light emitting element 130 and may include a first node N1, a second node N2, and a third node N3. The first node N1 may be a source or drain node and may be electrically connected to a first electrode of the light emitting element 130. The second node N2 may be a gate node and may be electrically connected to a source or drain node of the scan transistor SCT. The third node N3 may be a drain or source node and may be electrically connected to a driving voltage line DVL that supplies a driving voltage EVDD. For convenience of explanation, the following description will be given taking an example where the first node N1 is a source node and the third node N3 is a drain node.

[0042] The scan transistor SCT switches the connection between the data line DL and the second node N2 of the drive transistor DRT. The scan transistor SCT controls the connection between the second node N2 of the drive transistor DRT and a corresponding one of the data lines DL in response to a scan signal SCAN supplied from a scan line SCL, which is a type of gate line GL.

[0043] The storage capacitor Cst may be configured between the first node N1 and the second node N2 of the driving transistor DRT.

[0044] 1 is an example for explanatory purposes, and the subpixel SP may further include one or more transistors or one or more capacitors. Alternatively, each of the multiple subpixels may have the same structure, or some of the multiple subpixels may have different structures. Each of the drive transistor DRT and the scan transistor SCT may be an n-type transistor or a p-type transistor.

[0045] FIG. 2 is a plan view of a display device according to an embodiment of the present disclosure, and FIG. 3 is a cross-sectional view of the display device shown in FIG. 2 taken along line AA'.

[0046] 2 and 3, the foldable display device 100 may include a base substrate 110, a thin film transistor layer 120, a light emitting element 130, an adhesive layer 140, a touch panel 150, a polarizer 160, and a cover window 170. The configuration of the foldable display device 100 is not limited thereto, and at least one of these components may be omitted, or one or more additional components may be further included.

[0047] The base substrate 110 is for supporting various components of the foldable display device 100, and can be made of an insulating material such as glass, plastic, or polyimide (PI).

[0048] The base substrate 110 may include a display area AA, a non-display area NA, and a folding area FA. The display area AA may be an area where an image is displayed by a plurality of sub-pixels SP. The non-display area NA is an area where an image is not displayed and is positioned to surround the display area AA. A plurality of pads PAD may be disposed on one or both sides of the non-display area AA. For example, the non-display area NA may include a first non-display area NA1 disposed perpendicular to the folding axis FX of the folding area FA, a second non-display area NA2 disposed opposite the first non-display area NA1, and a third non-display area NA3 and a fourth non-display area NA4 extended between the first non-display area NA1 and the second non-display area NA2 and disposed opposite each other. The embodiment of the base substrate 110 is not limited thereto. For example, at least one of the first non-display area NA1 to the second non-display area NA2 may be omitted or be folded toward the rear of the folding display device 100 so as to be partially invisible from the front of the folding display device 100.

[0049] The folding area FA may be formed around the folding axis FX and overlap with a portion of the display area AA and a portion of the non-display area NA. For example, the folding area FA may be a region that bends with a predetermined curvature when the foldable display device 100 is bent around the folding axis FX. Areas other than the folding area FA may be non-folding areas NFA. For example, the non-folding areas NFA may extend on both sides of the folding area FA, and two non-folding areas NFA may be formed with the folding area FA sandwiched between them. While FIG. 2 illustrates one folding axis FX and one folding area FA, this is not limiting. For example, the foldable display device 100 may have two or more folding axes FX and two or more folding areas FA. In this case, the two or more folding axes FX may be arranged parallel to or non-parallel to each other. For example, the two or more folding axes FX may be arranged spaced apart from each other and intersect each other.

[0050] The thin film transistor layer 120 may be disposed on the display area AA and the non-display area NA of the base substrate 110. For example, the thin film transistor layer 120 may include a data line DL, a gate line GL, a driving transistor DRT, etc., and a pad PAD may be disposed in the non-display area NA of the thin film transistor layer 120.

[0051] The light emitting element 130 may be disposed on the thin film transistor layer 120. For example, the light emitting element 130 may be disposed only in the display area AA, or may be disposed in the display area AA and part of the non-display area NA. In this case, the end of the light emitting element 130 disposed in the non-display area NA may be formed so as not to overlap the pad PAD. That is, the light emitting element 130 may be formed to extend from the display area AA to the area in front of the pad PAD.

[0052] Referring to FIG. 1, the light emitting element 130 may include a first electrode 131 , a second electrode 132 and a light emitting layer 133 .

[0053] The first electrode 131 can be disposed independently in each sub-pixel SP as an anode.

[0054] The first electrode 131 may be formed of a transparent electrode such as indium tin oxide (ITO), indium zinc oxide (IZO), etc., or may be formed of an opaque electrode such as aluminum (Al), copper (Cu), nickel (Ni), etc. Alternatively, the first electrode 131 may be formed by laminating a transparent electrode and an opaque electrode.

[0055] The second electrode 132 may be provided as a cathode in the display area AA and the non-display area NA.

[0056] The second electrode 132 may be formed of a transparent electrode such as indium tin oxide (ITO), indium zinc oxide (IZO), etc., or may be formed of an opaque electrode such as aluminum (Al), copper (Cu), nickel (Ni), etc. Alternatively, the second electrode 132 may be formed by laminating a transparent electrode and an opaque electrode.

[0057] The light-emitting layer 133 may be disposed between the first electrode 131 and the second electrode 132. For example, the light-emitting layer 133 may be an organic light-emitting layer including an organic compound layer such as a hole injection layer (HIL), a hole transport layer (HTL), an emission material layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL). Examples of the light-emitting layer 133 are not limited thereto, and at least one of the hole injection layer (HIL), the hole transport layer (HTL), the active layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL) may be omitted in the subpixel SP.

[0058] The adhesive layer 140 is disposed on the light emitting element 130 and can bond the light emitting element 130 to the touch panel 150. For example, the adhesive layer 140 can be provided as an optically clear adhesive (OCA) that transmits more than 97% of light while having good adhesiveness and is suitable for use as an adhesive in the foldable display device 100.

[0059] The touch panel 150 may be disposed on the adhesive layer 140 as a touch sensor to provide not only an image display function but also a touch sensing function to the foldable display device 100. For example, the touch panel 150 may include a plurality of touch electrodes electrically connected via a plurality of touch electrode lines. The adhesive layer 140 and the touch panel 150 may be omitted depending on the design.

[0060] Although not shown, the foldable display device 100 may include a touch driving circuit that drives and senses the touch panel 150 to generate and output touch sensing data, and a touch controller that can sense the occurrence of a touch and detect the touch position using the touch sensing data.

[0061] The polarizing plate 160, which selectively transmits light to reduce reflection of external light incident on the display panel 1, can be disposed on the touch panel 150. For example, the polarizing plate 160 may be made of a material such as polyvinyl alcohol (PVA), polycarbonate (PC), or polymethacrylate (PMMA). The polarizing plate 160 may be omitted depending on the design.

[0062] The cover window 170 is for protecting the display panel 1 and can be disposed on the polarizer 160. The cover window 170 can be made of a glass material that has excellent optical properties, high strength and impact resistance, and excellent surface hardness. For example, the cover glass can be a thin cover glass (TCG) having a thickness of 90 μm or less. Such a thin cover glass with a limited thickness can effectively relieve stress applied during bending.

[0063] According to an embodiment of the present disclosure, at least one of the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170 arranged in the folding region FA may extend to the non-display region NA to overlap with and cover the pad PAD. That is, the pad PAD arranged in the folding region FA may be shielded by the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170. The embodiment is not limited to the illustrated example. As an example, at least one of the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170 arranged in the folding region FA may extend to the non-display region NA to cover the pad PAD. That is, at least one of the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170 arranged in the folding region FA may not extend to the non-display region NA. In addition, at least one or all of the light emitting element 130, adhesive layer 140, touch panel 150, polarizer 160, and cover window 170 arranged outside the folding area FA may extend to the non-display area NA to cover the pad PAD. In addition, at least one or all of the light emitting element 130, adhesive layer 140, touch panel 150, polarizer 160, and cover window 170 arranged outside the folding area FA may not extend to the non-display area NA.

[0064] This makes it possible to prevent moisture from flowing into the pad PAD from the folding area FA without providing a resin to cover the pad PAD. That is, in the past, the pad PAD arranged in the folding area FA was not shielded by the light emitting element 130 arranged above, the adhesive layer 140, the touch panel 150, the polarizing plate 160, and the cover window 170, and therefore a resin was separately provided to cover the pad PAD.

[0065] When the pad PAD is shielded by resin in this way, there is no problem in the non-folding area NFA, but in the folding area FA, stress caused by bending and restoring of the foldable display device continuously acts on the resin, which may cause the resin to lift up. In this case, cracks may occur in the pad PAD that was attached to the resin, causing damage, and moisture may enter the gap between the display panel 1 and the resin, reducing the reliability of the foldable display device 100.

[0066] To solve this problem, the foldable display device 100 of this embodiment eliminates the resin disposed in the folding area FA and covers the pad PAD via the light-emitting element 130, adhesive layer 140, touch panel 150, polarizer 160 and cover window 170 that constitute the display panel 1, thereby improving moisture resistance.

[0067] Specifically, at least one of the light emitting element 130, adhesive layer 140, touch panel 150, polarizer 160, and cover window 170 covering the pad in the folding area FA may have both sides extending outside the folding area FA and overlapping with a portion of the non-folding area NFA disposed on both sides of the folding area FA (see FIG. 2 ). This configuration increases the area covering the pad and improves moisture resistance. In addition, at least one or each of the light emitting element 130, adhesive layer 140, touch panel 150, polarizer 160, and cover window 170 covering the pad in the folding area FA may extend only one side outside the folding area FA to overlap with a portion of the non-folding area NFA disposed on only one side of the pad in the folding area FA. In addition, at least one or each of the light-emitting element 130, adhesive layer 140, touch panel 150, polarizer 160 and cover window 170 that cover the pad PAD of the folding area FA may not extend from both sides of the folding area FA to the outside of the folding area FA.

[0068] FIG. 4 is a cross-sectional view taken along line BB' in FIG.

[0069] 4, the foldable display device 100 may be arranged such that the edges of the light emitting element 130, adhesive layer 140, touch panel 150, polarizer 160, and cover window 170 located in the non-folding area NFA do not overlap with the pad PAD. That is, they may be formed to cover the pad PAD only in the folding area FA, and not cover the pad PAD in the non-folding area NFA. However, the structures of the light emitting element 130, adhesive layer 140, touch panel 150, polarizer 160, and cover window 170 located in the non-folding area NFA are not limited to those illustrated, and they may also be formed to cover the pad PAD as in the folding area FA.

[0070] FIG. 5 is a diagram showing the mid-plane in FIG.

[0071] 5, in the foldable display device 100 according to this embodiment, the components constituting the display panel 1 can be arranged side by side so as to avoid steps at their edges. For example, the thin film transistor layer 120, the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170 constituting the display panel 1 can be arranged side by side in a row so as to avoid steps at their edges.

[0072] As a result, no step is formed at the edge of the display panel 1, and thus the neutral plane (NP) that occurs when the folding area FA is bent can be maintained constant. Here, the neutral plane NP refers to a plane where the stress state becomes zero when bending. That is, the neutral plane NP refers to a plane that bends while maintaining its original length without expanding or contracting when a bending moment is applied. The shape of the edge of the display panel 1 is not limited to the example shown. For example, a step may be formed at the edge of at least one of the thin film transistor layer 120, the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170 of the display panel 1.

[0073] FIG. 6 is a diagram showing the neutral surface in FIG.

[0074] 6, steps may be formed in each member in the non-folding area NFA of the foldable display device 100. In this manner, when steps are formed in the display panel 1 in the non-folding area NFA, the neutral plane NP may be located between each of the members where the steps are formed.

[0075] Since the non-folding area NFA is an area where bending and restoration do not occur, the presence of the neutral plane NP between the components does not affect durability. However, if the neutral plane NP is located between the components in the folding area FA, stresses of different magnitudes act on the boundary of the neutral plane NP during bending and restoration of the folding area FA, causing distortion, which can cause cracks in the display panel 1.

[0076] Therefore, in the foldable display device 100 according to this embodiment, the edges of each member located in the folding area FA are formed without steps, thereby maintaining a constant neutral plane NP and preventing cracks from occurring during bending and restoring of the folding area FA, as shown in Fig. 5. Alternatively, at least one or each of the members located in the non-folding area NFA may have edges without steps.

[0077] Meanwhile, when the display panel 1 is bent, compressive stress acts on the inside of the curvature and compressive stress acts on the outside. In this case, the magnitude of the tensile or compressive stress in the display panel 1 is determined in proportion to the distance from the neutral plane NP. Therefore, the magnitude of the tensile or compressive stress increases as the distance from the neutral plane NP increases.

[0078] In consideration of this, in the foldable display device 100 according to this embodiment, the neutral plane NP generated when the folding region FA is bent may be located on the adhesive layer 140 (see FIG. 5 ). That is, by forming the neutral plane NP in the folding region FA to be located at the center in the thickness direction of the display panel 1, stress acting on each component during bending and restoration can be evenly distributed, thereby minimizing damage to the folding region FA. The position of the neutral plane NP can be determined by controlling the thickness of each component constituting the display panel 1. In this embodiment, the adhesive layer 140 is illustrated and described as being located at the center of the display panel 1, but this is not limiting. For example, at least one of the thin film transistor layer 120, the light emitting element 130, the adhesive layer 140, the touch panel 150, the polarizer 160, and the cover window 170 may be located at the center of the display panel 1.

[0079] The foldable display device 100 in this embodiment may be of a landscape type having a screen ratio that is long in the horizontal direction.

[0080] For example, in a landscape-type foldable display device 100, the display area AA is formed in a rectangular shape that is elongated in the horizontal direction, and the non-display area NA surrounding the display area AA includes a first non-display area NA1 arranged perpendicular to the folding axis FX of the folding area FA, a second non-display area NA2 arranged opposite the first non-display area NA1, and a third non-display area NA3 and a fourth non-display area NA4 that are formed extending between the first non-display area NA1 and the second non-display area NA2 and arranged opposite each other.

[0081] A plurality of pads PADs provided on the thin film transistor layer 120 may be arranged in the first non-display area NA1 and the second non-display area NA2, respectively. For example, the pads PADs arranged in the first display area AA may be connected to the data driver 180, and the pads PADs arranged in the second display area AA may be connected to the touch driver 190.

[0082] The data driver 180 may include a first circuit film 181 , a data driver circuit 182 , and a first printed circuit board 183 .

[0083] A plurality of first circuit films 181 may be provided in the first non-display area NA1, and the input terminals provided on one side of each of the plurality of first circuit films 181 may be attached to the first printed circuit board 183 by a film attaching process, and the output terminals provided on the other side may be attached to pads PAD arranged in the first non-display area NA1 by a film attaching process.

[0084] The pads PAD arranged in the first non-display area NA1 are for supplying driving signals to the data lines DL, the gate lines GL, and the driving voltage lines DVL, respectively, and each of the plurality of first circuit films 181 may be embodied as a flexible circuit film and bendable in order to reduce the non-display area NA of the foldable display device 100. For example, the plurality of circuit films may be made of a tape carrier package (TCP) or a chip on film (COF).

[0085] A plurality of data driving circuits 182 may be provided, and each data driving circuit 182 unit may be individually mounted on each of the plurality of first circuit films 181. The data driving circuits 182 receive video data and data control signals from the controller 30, and convert the video data into analog data signals according to the data control signals and supply them to the corresponding data lines.

[0086] The first printed circuit board 183 may be connected to the first circuit film 181 and transmit signals and power between components of the data driver 180. For example, the number of first printed circuit boards 183 may be the same as the number of non-folding areas NFA, and may be connected via a thin connection film 184. Signal transmission wiring and various power wiring for transmitting signals and power may be provided on the first printed circuit board 183.

[0087] The touch driver 190 may include a second circuit film 191 and a second printed circuit board 192 .

[0088] A plurality of second circuit films 191 may be provided in the second non-display area NA2, and input terminals provided on one side of each second circuit film 191 may be attached to the second printed circuit board 192 by a film bonding process, and output terminals provided on the other side may be attached to pads PADs arranged in the second non-display area NA2 by a film bonding process. Here, the pads PADs arranged in the second non-display area NA2 are for driving the touch panel 150, and each of the plurality of second circuit films 191 may be embodied as a flexible circuit film and be bendable in order to reduce the non-display area NA of the foldable display device 100.

[0089] The second printed circuit boards 192 may be connected to the second circuit film 191 and may supply touch drive signals for driving the touch panel 150. For example, the second printed circuit boards 192 may be disposed in the non-folding areas NFA, and may be electrically connected to the pads PAD disposed in the second non-display area NA2 via the second circuit film 191.

[0090] The above-described embodiment of the present disclosure can be briefly described as follows.

[0091] According to an embodiment of the present disclosure, a foldable display device can be provided that includes a base substrate including a display area, a non-display area surrounding the display area and having a plurality of pads arranged on one or both sides, and a folding area overlapping part of the display area and the non-display area; a light-emitting element arranged in the display area of ​​the base substrate; and a cover window arranged on the light-emitting element, wherein at least one of the light-emitting element and the cover window arranged in the folding area extends to the non-display area and overlaps with the pads.

[0092] According to an embodiment of the present disclosure, non-folding areas are formed on both sides of the folding area, and the light-emitting element and the edge of the cover window located in the non-folding area can be positioned so as not to overlap with the pad.

[0093] According to an embodiment of the present disclosure, the light-emitting element and / or cover window that overlaps the pad in the folding region can have both sides extending outside the folding region and overlapping with portions of the non-folding region located on both sides of the folding region.

[0094] According to an embodiment of the present disclosure, the edges of the light emitting element and the cover window in the folding region can be formed side by side so that no step is formed.

[0095] According to an embodiment of the present disclosure, the foldable display device may include a thin film transistor layer disposed between the base substrate and the light-emitting element.

[0096] According to an embodiment of the present disclosure, the foldable display device may further include an adhesive layer disposed on the light-emitting element; a touch panel disposed on the adhesive layer; and a polarizer disposed on the touch panel.

[0097] According to an embodiment of the present disclosure, a thin film transistor layer is disposed on the display area and the non-display area of ​​the base substrate, and a pad can be formed on the non-display area of ​​the thin film transistor layer.

[0098] According to an embodiment of the present disclosure, an edge of at least one of the touch panel, adhesive layer, and polarizer located in the folding area can extend to the non-display area to cover the pad.

[0099] According to an embodiment of the present disclosure, the light-emitting element, the cover window, the thin film transistor layer, the touch panel, and the ends of the adhesive layer and polarizer located in the folding area can be arranged side by side so that no steps are formed.

[0100] According to embodiments of the present disclosure, the neutral plane that occurs during bending of the folding region can be located on the adhesive layer.

[0101] According to an embodiment of the present disclosure, non-folding areas are formed on both sides of the folding area, and the touch panel located in the non-folding area and the ends of the adhesive layer and polarizer can be arranged so as not to overlap with the pad.

[0102] According to an embodiment of the present disclosure, the light-emitting element, the cover window, the thin film transistor layer, the adhesive layer, and the end of at least one of the touch panel and polarizer arranged in the non-folding region can be arranged so as to form a step.

[0103] According to an embodiment of the present disclosure, the display area is formed in a rectangular shape, and the non-display area surrounding the display area includes a first non-display area arranged perpendicular to the folding axis of the folding area, a second non-display area arranged opposite the first non-display area, and a third non-display area and a fourth non-display area formed to extend between the first non-display area and the second non-display area and arranged opposite each other, and a plurality of pads can be arranged in the first non-display area and the second non-display area.

[0104] According to an embodiment of the present disclosure, the pads disposed in the first display area can be connected to a data driver.

[0105] According to an embodiment of the present disclosure, the pad disposed in the second display area can be connected to the touch driver.

[0106] According to an embodiment of the present disclosure, the neutral plane that occurs when the folding region is bent can be located at the center of the thickness of the foldable display device.

[0107] According to embodiments of the present disclosure, the folding region may be a region that bends when the foldable display is bent about a folding axis.

[0108] According to an embodiment of the present disclosure, a foldable display device can be provided, which includes a base substrate including a display area, a non-display area surrounding the display area and having a plurality of pads arranged on one or both sides thereof, and a folding area overlapping the display area and a portion of the non-display area; a thin film transistor layer arranged on the base substrate; a light-emitting element arranged on the thin film transistor layer; an adhesive layer arranged on the light-emitting element; a touch panel arranged on the adhesive layer; a polarizer arranged on the touch panel; and a cover window arranged on the light-emitting element, wherein the edges of the thin film transistor layer, light-emitting element, adhesive layer, touch panel, polarizer, and cover window located in the folding area are arranged side by side, and no steps are formed.

[0109] According to embodiments of the present disclosure, the neutral plane that occurs during bending of the folding region can be located on the adhesive layer.

[0110] According to an embodiment of the present disclosure, in the folding area, the thin film transistor layer, the light-emitting element, the adhesive layer, the touch panel, and at least one end of the polarizer and the cover window can be arranged in the non-display area.

[0111] According to an embodiment of the present disclosure, a thin film transistor layer is disposed on the display area and the non-display area of ​​the base substrate, and a pad can be formed on the non-display area of ​​the thin film transistor layer.

[0112] According to an embodiment of the present disclosure, non-folding areas are formed on both sides of the folding area, and the light-emitting element, adhesive layer, touch panel, polarizer, and edges of the cover window located in the non-folding area can be arranged so as not to overlap with the pad.

[0113] According to an embodiment of the present disclosure, at least one of the light-emitting element, the adhesive layer, the touch panel, the polarizer, and the cover window located in the folding region can cover the pad.

[0114] According to an embodiment of the present disclosure, at least one of the light-emitting element, adhesive layer, touch panel, polarizer, and cover window covering the pad in the folding area may have both side portions extending outside the folding area and overlapping with a portion of the non-folding area disposed on both sides of the folding area.

[0115] According to an embodiment of the present disclosure, one or both sides of the non-display area may be oriented perpendicular to the folding axis of the folding area.

[0116] The above description merely exemplifies the technical idea of ​​the present disclosure, and various modifications and variations are possible by a person having ordinary skill in the art to which the present disclosure pertains without departing from the essential characteristics of the present disclosure. Furthermore, the examples disclosed in the present disclosure are intended to illustrate, rather than limit, the technical idea of ​​the present disclosure, and therefore the scope of the technical idea of ​​the present disclosure is not limited by such examples. [Explanation of symbols]

[0117] 100: Folding display device 110: Base board 120: Thin film transistor layer 130: Light emitting element 140: Adhesive layer 150:Touch panel 160: Polarizing plate 170: Cover window 180: Data driver 190: Touch drive unit

Claims

1. a base substrate including a display area, a non-display area surrounding the display area and having a plurality of pads disposed on one side or two opposing sides thereof, and a folding area overlapping the display area and a portion of the non-display area; a light-emitting element disposed in the display region of the base substrate; and a cover window disposed over the light emitting element; At least one of the light emitting element and the cover window disposed in the folding region extends to the non-display region and overlaps with the pad; A foldable display device, wherein non-foldable areas are formed on both sides of the folding area, and edges of the light-emitting element and the cover window located in the non-foldable areas are arranged so as not to overlap with the pad.

2. 2. The foldable display device of claim 1, wherein the light-emitting element and / or the cover window overlapping the pad in the folding region extend on one or two sides outside the folding region and overlap with a portion of a non-folding region disposed on one or both sides of the folding region.

3. The foldable display device according to claim 1 , wherein in the folding region, edges of the light-emitting element and the cover window are arranged side by side so as to avoid forming a step.

4. The foldable display device according to claim 1 , further comprising a thin film transistor layer disposed between the base substrate and the light-emitting element.

5. an adhesive layer disposed on the light-emitting element; a touch panel disposed on the adhesive layer; and The foldable display device of claim 4 , further comprising a polarizer disposed on the touch panel.

6. The foldable display device according to claim 4 , wherein the thin film transistor layer is disposed on the display area and the non-display area of ​​the base substrate, and the pad is formed on the non-display area of ​​the thin film transistor layer.

7. The foldable display device of claim 5 , wherein an end portion of at least one of the touch panel, the adhesive layer, and the polarizer located in the folding area extends to the non-display area to cover the pad.

8. 6. The foldable display device of claim 5, wherein the light-emitting element, the cover window, the thin film transistor layer, the touch panel, the adhesive layer, and the polarizer are arranged side by side in the folding region so as to avoid forming any steps.

9. The foldable display device of claim 5 , wherein a neutral plane that occurs when the folding region is bent is located on the adhesive layer.

10. 6. The foldable display device of claim 5, wherein non-foldable areas are formed on both sides of the folding area, and edges of the touch panel, the adhesive layer, and the polarizer located in the non-foldable areas are arranged so as not to overlap with the pad.

11. 11. The foldable display device of claim 10, wherein at least one edge of the light-emitting element, the cover window, the thin film transistor layer, the adhesive layer, the touch panel, and the polarizer arranged in the non-foldable region is arranged to form at least one step.

12. the display area is formed in a rectangular shape, and the non-display area surrounding the display area includes a first non-display area arranged in a direction perpendicular to a folding axis of the folding area, a second non-display area arranged to face the first non-display area, and a third non-display area and a fourth non-display area extending between the first non-display area and the second non-display area and facing each other, The foldable display device according to claim 1 , wherein the pads are arranged in the first non-display area and the second non-display area.

13. The foldable display device of claim 12 , wherein the pads arranged in the first non-display area are connected to a data driver.

14. The foldable display device according to claim 12 , wherein the pad disposed in the second non-display area is connected to a touch driver.

15. The foldable display device of claim 1 , wherein a neutral plane that occurs when the folding region is bent is located at the center in the thickness direction of the foldable display device.

16. The foldable display of claim 1 , wherein the folding region is a region that bends when the foldable display is bent around a folding axis.

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