Display device and method for manufacturing the same

Abstract

The present disclosure relates to a display device and a method for manufacturing the display device, wherein the display device comprises: a display panel, wherein the display panel has a folding area folded along a virtual folding axis and a first non-folding area and a second non-folding area adjacent to both sides of the folding area; and a window, wherein the window is arranged on the display panel; the method comprises: preparing a mother substrate, wherein the mother substrate has an effective area and an invalid area divided by a cutting line; performing a first laser process along a first cutting line arranged in the first non-folding area; performing a second laser process along a second cutting line arranged in the second non-folding area; and performing a third laser process along a third cutting line arranged in the folding area, wherein one end of the third cutting line overlaps with the first end of the first cutting line, and the other end of the third cutting line overlaps with the first end of the second cutting line.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0090091 filed on Jul. 25, 2019, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Exemplary embodiments of the present disclosure relate generally to a display device and a method for manufacturing the display device, and, more particularly, to a foldable display device and a manufacturing method for manufacturing the foldable display device. Background Art

[0004] Electronic devices such as televisions, mobile phones, tablet computers, navigation devices, and game consoles are provided with display devices for providing information.

[0005] In recent years, with the development of display device technology, various types of display devices have been developed. For example, a foldable (or bendable) or rollable flexible display device is being developed. A flexible display device whose shape can be modified in various ways can be easily carried and improves user convenience.

[0006] The above information disclosed in this Background section is only for understanding the background of the inventive concept and therefore it may contain information that does not constitute prior art. Summary of the invention

[0007] A foldable display device and a method for manufacturing the foldable display device constructed according to exemplary embodiments of the present disclosure can improve reliability.

[0008] Additional features of the inventive concept will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concept.

[0009] A method for manufacturing a display device, the display device comprising: a display panel, the display panel having a folding area configured to be folded along a virtual folding axis and a first non-folding area and a second non-folding area adjacent to both sides of the folding area; and a window, the window being arranged on the display panel and configured to be folded together with the display panel, the method comprising: preparing a mother substrate, the mother substrate having an effective area and an invalid area divided by a cutting line as a boundary, performing a first laser process along a first cutting line of a cutting line arranged in the first non-folding area, performing a second laser process along a second cutting line of a cutting line arranged in the second non-folding area, and performing a third laser process along a third cutting line of a cutting line arranged in the folding area, wherein a first end of the third cutting line overlaps with a first end of the first cutting line, and a second end of the third cutting line overlaps with a first end of the second cutting line.

[0010] The third laser process may be performed by irradiating a second laser beam having energy smaller than that of a first laser beam used in the first laser process.

[0011] The first laser beam may be irradiated at a first rate in the first laser process, and the second laser beam may be irradiated at a second rate greater than the first rate in the third laser process.

[0012] The second laser process may be performed by irradiating the first laser beam.

[0013] The first cutting line may include a first start point and a first end point, the second cutting line may include a second start point and a second end point, and the third cutting line may include a third start point and a third end point.

[0014] A third starting point of the third cutting line may be disposed on the first cutting line, and a third ending point of the third cutting line may be disposed on the second cutting line.

[0015] The third laser process may start at a third starting point of the third cutting line and end at a third ending point of the third cutting line while passing through the first starting point of the first cutting line and the second ending point of the second cutting line.

[0016] Each of the first laser process and the second laser process can be performed by irradiating a first laser beam having a first energy level, and the third laser process may include: a first sub-laser process, irradiating a second laser beam having a third energy level from a third starting point of the third cutting line to a first starting point of the first cutting line; a second sub-laser process, irradiating a second laser beam having a third energy level from the first starting point of the first cutting line to a second end point of the second cutting line; and a third sub-laser process, irradiating a second laser beam having a second energy level from the second end point of the second cutting line to a third end point of the third cutting line; and the first energy level, the second energy level, and the third energy level may have different laser powers from each other.

[0017] The first energy level may be greater than the second energy level, and the second energy level may be greater than the third energy level.

[0018] The method may further include performing a fourth laser process along a fourth cutting line of the cutting lines disposed in the folding region, wherein a first end of the fourth cutting line overlaps a second end of the first cutting line, and a second end of the fourth cutting line overlaps a second end of the second cutting line.

[0019] A fourth starting point of the fourth cutting line may be disposed on the first cutting line, and a fourth ending point of the fourth cutting line may be disposed on the second cutting line.

[0020] Each of the first and second laser processes may be performed by irradiating a first laser beam having a first energy level; and the fourth laser process may be performed by irradiating a second laser beam having energy less than that of the first laser beam.

[0021] The first to fourth cutting lines may form a closed curve shape surrounding the effective area, and after the first to fourth laser processes are performed along the first to fourth cutting lines, the ineffective area of ​​the mother substrate may be removed.

[0022] According to another exemplary embodiment, a display device includes: a display panel, the display panel is configured to display an image, and includes a folding area configured to be folded along a virtual folding axis and a non-folding area adjacent to one side of the folding area; and a window, the window is arranged on the display panel and includes a soft material, so that the window is configured to be folded together with the display panel; wherein: the non-folding area includes a first area and a second area arranged sequentially in a first direction, and the second area is arranged adjacent to the folding area; and a portion of the side surface of the window arranged in the first area has a first width range from a baseline parallel to the first direction, and a portion of the side surface of the window arranged in the second area has a second width range from the baseline that is different from the first width range.

[0023] The second width range may be greater than the first width range.

[0024] The window may include a base layer, a window function layer disposed on the base layer, and a window protection layer covering the window function layer.

[0025] The side surface of the window may include a side surface of the base layer, a side surface of the window function layer, and a side surface of the window protection layer.

[0026] A portion of the side surface of the window in the non-folding region may have a first surface roughness, and a portion of the side surface of the window in the folding region may have a second surface roughness smaller than the first surface roughness.

[0027] The display device may further include a functional layer disposed between the display panel and the window.

[0028] The display device may further include a protective film disposed on a rear surface of the display panel.

[0029] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description serve to explain the inventive concept.

[0031] Figure 1 is a perspective view of a display device according to an exemplary embodiment.

[0032] Figure 2A It is shown Figure 1 A view of a state where the display device is folded along a first folding axis.

[0033] Figure 2B It is shown Figure 1 A view showing a state in which the display device is folded outwardly along a first folding axis.

[0034] Figure 3A It is shown Figure 1 A view showing a state in which the display device is folded along the second folding axis.

[0035] Figure 3B It is shown Figure 1 A view showing a state in which the display device is folded outwardly along the second folding axis.

[0036] Figure 4 is an exploded view of a display module according to an exemplary embodiment.

[0037] Figure 5 yes Figure 4 A plan view of the display module.

[0038] Fig. 6A is along Figure 5 A cross-sectional view of the non-folding area taken along line II'.

[0039] Figure 6B is along Figure 5 A cross-sectional view of the folding area taken along line II-II'.

[0040] Fig. 7A is along Figure 5 A cross-sectional view taken along line III-III'.

[0041] Figure 7B It is shown Figure 5 A cross-sectional view of a state in which a portion of a display panel is bent.

[0042] Fig. 8A , Figure 8B , Figure 8C and Fig.8D is a plan view illustrating a process of manufacturing a display panel according to an exemplary embodiment.

[0043] Fig. 9 It is shown as an example FIG. 8A to FIG. 8D A view of the first starting point to the fourth starting point and the first end point to the fourth end point on the mother substrate.

[0044] Fig.10 is a view exemplarily showing a mother substrate according to another exemplary embodiment.

[0045] Fig.11A , Fig. 11B , Fig. 11C , Fig.11D and Fig.11E It shows that the setting Fig.10 Photographs of the side surfaces of the display substrates on areas A1, A2, A3, A4 and A5. DETAILED DESCRIPTION

[0046] In the following description, for the purpose of explanation, many specific details are stated in order to provide a thorough understanding of various exemplary embodiments or implementations of the present disclosure. As used herein, "embodiment" and "implementation" are interchangeable words, which are non-limiting examples of devices or methods to which one or more inventive concepts disclosed herein are applied. However, it is readily understood that various exemplary embodiments can be practiced without these specific details or with one or more equivalent arrangements. In other examples, well-known structures and devices are shown in block diagram form to avoid unnecessary confusion of various exemplary embodiments. Further, various exemplary embodiments may be different, but do not have to be exclusive. For example, without departing from the inventive concept, the specific shape, configuration and characteristics of the exemplary embodiment may be used or implemented in another exemplary embodiment.

[0047] Unless otherwise specified, the exemplary embodiments shown will be understood as providing exemplary features of varying details of some ways in which the inventive concept can be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions and / or aspects of the various embodiments (hereinafter individually or collectively referred to as "elements") may be combined, separated, interchanged and / or rearranged without departing from the inventive concept.

[0048] The use of cross-hatching and / or shading is often provided in the drawings to clarify the boundaries between adjacent elements. Thus, unless otherwise specified, the presence or absence of cross-hatching or shading cannot convey or indicate a preference or requirement for a specific material, material property, size, ratio, commonality between the illustrated elements, and / or any other feature, attribute, characteristic, etc. of an element. Further, in the drawings, the size and relative size of the elements may be exaggerated for clarity and / or descriptive purposes. When exemplary embodiments may be implemented differently, a specific processing sequence may be performed differently from the described sequence. For example, two consecutively described processes may be performed substantially simultaneously or in an order opposite to the described sequence. Likewise, the same reference numerals represent the same elements.

[0049] When an element or layer is referred to as being "on" another element or layer, "connected to" or "coupled to" another element or layer, it may be directly on, connected to or coupled to other elements or layers, or an intermediate element or layer may exist. However, when an element or layer is referred to as being "directly on" another element or layer, "directly connected to" or "directly coupled to" another element or layer, there is no intermediate element or layer. For this reason, the term "connection" may refer to physical, electrical and / or fluid connections with or without intermediate elements. Further, the D1 axis, the D2 axis, and the D3 axis are not limited to the three axes of a rectangular coordinate system, such as an x-axis, a y-axis, and a z-axis, and may be interpreted in a broader sense. For example, the D1 axis, the D2 axis, and the D3 axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0050] Although the terms "first", "second", etc. may be used to describe various types of elements in this article, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Therefore, without departing from the teachings of the present disclosure, the first element discussed below may be referred to as the second element.

[0051] Spatially relative terms, such as "below," "under," "below," "down," "above," "upper," "above," "higher," "side" (e.g., in a "sidewall"), and the like, may be used herein for descriptive purposes and, therefore, to describe the relationship of one element to another element as shown in the accompanying drawings. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, elements described as "below" or "below" other elements or features would be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both the "above" and "below" orientations. Further, the device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and, therefore, the spatially relative terms used herein are interpreted accordingly.

[0052] The terms used in this article are for the purpose of describing specific embodiments and are not restrictive. As used herein, the singular forms "a", "an" and "said" are also intended to include plural forms, unless the context clearly indicates otherwise. In addition, when used in this specification, the terms "comprises", "comprising", "include" and / or "including" specify the presence of the features, integers, steps, operations, elements, components and / or groups thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should also be noted that, as used herein, the terms "substantially", "approximately" and other similar terms are used as approximate terms rather than terms of degree, and, therefore, are used to explain the inherent deviations in the values ​​measured, calculated and / or provided that will be recognized by one of ordinary skill in the art.

[0053] Various exemplary embodiments are described herein with reference to cross-sectional views and / or exploded views, which are schematic diagrams of idealized exemplary embodiments and / or intermediate structures. As such, variations in the illustrated shapes, for example due to manufacturing techniques and / or tolerances, are to be expected. Therefore, the exemplary embodiments disclosed herein need not necessarily be construed as limited to the specific illustrated shapes of the regions, but rather include shape deviations caused by, for example, manufacturing. In this manner, the regions shown in the drawings may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device, and therefore, this is not necessarily limiting.

[0054] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless clearly so provided herein.

[0055] Hereinafter, exemplary embodiments of the inventive concept will be described with reference to the accompanying drawings.

[0056] Figure 1 is a perspective view of a display device according to an exemplary embodiment.

[0057] Reference Figure 1 , the display device DD according to the exemplary embodiment has a substantially rectangular shape having short sides in a first direction DR1 and long sides in a second direction DR2 crossing the first direction DR1. However, the inventive concept is not limited to a specific shape of the display device DD, and in other exemplary embodiments, the display device DD may have various shapes.

[0058] The display device DD may be a foldable electronic device. More specifically, the display device DD according to the exemplary embodiment may be folded about folding axes FX1 and FX2 extending in respective predetermined directions. Hereinafter, the folded state about the folding axes FX1 and FX2 may be referred to as a folded state, and the unfolded state may be referred to as a non-folded state.

[0059] The folding axes FX1 and FX2 may extend in the first direction DR1 or in the second direction DR2. In an exemplary embodiment, the folding axis extending in the second direction DR2 is defined as the first folding axis FX1, and the folding axis extending in the first direction DR1 is defined as the second folding axis FX2. The display device DD may include only one of the first folding axis FX1 and the second folding axis FX2. Specifically, the display device DD may be folded along the first folding axis FX1 or the second folding axis FX2.

[0060] The display device DD can be used for large display devices such as televisions and monitors, and small and medium display devices such as mobile phones, tablet computers, vehicle navigation devices, and game consoles. However, the inventive concept is not limited thereto, and in other exemplary embodiments, the display device DD can be adopted by other electronic devices.

[0061] like Figure 1As shown in FIG, the display device DD displays an image IM in a third direction on a display surface IS parallel to each of the first direction DR1 and the second direction DR2. The display surface IS on which the image IM is displayed may correspond to a front surface of the display device DD.

[0062] The display surface IS of the display device DD may be divided into a plurality of regions. A display area DA and a non-display area NDA may be defined on the display surface IS of the display device DD.

[0063] The display area DA may be an area on which an image IM is displayed, and a user may see the image IM through the display area DA. The display area DA may have a substantially rectangular shape. The non-display area NDA may surround the display area DA. Therefore, the shape of the display area DA may be substantially defined by the non-display area NDA. However, the inventive concept is not limited thereto. For example, in some exemplary embodiments, the non-display area NDA may be provided to be adjacent to only one side of the display area DA, or may be omitted. The display device DD according to the exemplary embodiments may be implemented in various ways and is not limited to a specific exemplary embodiment.

[0064] The non-display area NDA is an area adjacent to the display area DA and on which the image IM is not displayed. A bezel area of ​​the display device DD may be defined by the non-display area NDA.

[0065] The non-display area NDA may surround the display area DA. However, the inventive concept is not limited thereto. For example, in some exemplary embodiments, the non-display area NDA may be disposed adjacent to only a portion of an edge of the display area DA.

[0066] The display device DD can sense the user input TC applied from the outside. The user input TC includes various types of external inputs, such as a part of the user's body, light, heat or pressure, etc. In the exemplary embodiment shown, the user input TC is exemplarily shown as the user's hand applied to the front surface. However, the inventive concept is not limited to this. As described above, the user input TC can be provided in various forms, for example, input using the user's hand and input using a mechanism such as a touch pen or a stylus, etc. In addition, the display device DD can sense the user input TC applied to the side surface or the rear surface of the display device DD according to the structure of the display device DD, but is not limited to this.

[0067] The display device DD may activate the display surface IS to display the image IM and also sense the external input TC. In the illustrated exemplary embodiment, the area on which the external input TC is sensed may be provided on the display area DA on which the image IM is displayed. However, the inventive concept is not limited thereto. For example, the area on which the external input TC is sensed may be provided on the non-display area NDA, or may be provided on the entire area of ​​the display surface IS.

[0068] Figure 2A It is shown Figure 1 A view of a state where the display device is folded along a first folding axis, and Figure 2B It is shown Figure 1 A view showing a state in which the display device is folded outwardly along a first folding axis.

[0069] Reference Figure 1 and Figure 2A , the display device DD can be folded inwardly about the first folding axis FX1.

[0070] A plurality of regions may be defined on the display device DD according to the operation type. The plurality of regions may be divided into a folding region FA and at least one non-folding region NFA1 or NFA2. The folding region FA is defined between the two non-folding regions NFA1 and NFA2.

[0071] According to an exemplary embodiment, the non-folding areas NFA1 and NFA2 may include a first non-folding area NFA1 and a second non-folding area NFA2. The first non-folding area NFA1 may be adjacent to one side of the folding area FA in the first direction DR1, and the second non-folding area NFA2 may be adjacent to the other side of the folding area FA in the first direction DR1.

[0072] The display device DD may be folded inwardly or outwardly. As used herein, folding inwardly means that the display surfaces IS are folded to face each other, and folding outwardly means that the rear surfaces of the display device DD are folded to face each other.

[0073] The folding area FA is an area folded about the first folding axis FX1 to substantially form a curvature. The first folding axis FX1 may extend in a second direction DR2, ie, in a direction substantially parallel to a long side of the display device DD (long side direction).

[0074] Figure 2A The display device DD shown in FIG. 1 may be folded inwardly so that a display surface IS of a first non-folding area NFA1 and a display surface IS of a second non-folding area NFA2 face each other.

[0075] Reference Figure 2B , the display device DD may be folded outwardly about the first folding axis FX1. When the display device DD is folded outwardly, the display surface IS may be exposed to the outside.

[0076] In an exemplary embodiment, the display device DD may be inwardly folded and outwardly folded. However, in the following description, the display device DD will be exemplarily described as being inwardly folded or outwardly folded.

[0077] Figure 3A It is shown Figure 1 A view of a state where the display device is folded inwardly along a second folding axis, and Figure 3B It is shown Figure 1 A view showing a state in which the display device is folded outwardly along the second folding axis.

[0078] Reference Figure 3A and Figure 3B , the display device DD may be folded inwardly or outwardly about the second folding axis FX2. The second folding axis FX2 may extend in the first direction DR1, for example, in a direction substantially parallel to the short sides of the display device DD (short side direction).

[0079] In the illustrated exemplary embodiment, although the display device DD is illustrated as including one folding area FA, the inventive concept is not limited thereto. According to another exemplary embodiment, a plurality of folding areas may be defined on the display device DD.

[0080] Figure 4 is an exploded view of a display module DM according to an exemplary embodiment, and Figure 5 yes Figure 4 A plan view of the display module.

[0081] The display module DM according to an exemplary embodiment may include a display panel DP displaying an image and a window module WM disposed on the display panel DP. The display module DM may form a display device DD (see FIG. Figure 1 ) and, in particular, the display module DM may provide a display surface IS of the display device DD (see Figure 1 ).

[0082] The display panel DP may be a flexible display panel. Therefore, the display panel DP may be folded or unfolded about the first folding axis FX1. According to an exemplary embodiment, the display panel 110 may be an organic light emitting display panel.

[0083] The display panel DP may be divided into a folding area FA, a first non-folding area NFA1, and a second non-folding area NFA2. The display panel DP may be divided into a non-bending area NBA and a bending area BA. A portion of the folding area FA, the first non-folding area NFA1, and the second non-folding area NFA 2 of the display panel DP may be disposed on the non-bending area NBA, and another portion of the second non-folding area NFA2 may be disposed on the bending area BA. The bending area BA will be described in detail later.

[0084] The top surface of the window module WM defines Figure 1 . The display surface IS of the display device DD shown in FIG. The window WM may be optically transparent. Therefore, an image generated in the display panel DP may pass through the window module WM and be easily recognized by the user.

[0085] The window module WM may be made of a flexible material. Therefore, the window module WM may be folded or unfolded about the first folding axis FX1. More specifically, the window module WM may be deformed in shape as the display panel DP is deformed in shape.

[0086] The window module WM may transmit an image transmitted from the display panel DP, and may also mitigate external impacts to protect the display panel DP from damage or malfunction caused by the external impacts. The external impact may be a force applied from the outside, which is expressed as pressure or stress, etc., such as a force causing defects in the display panel DP. The window module WM may prevent defects in the display panel DP by mitigating bending deformation, compression deformation, and / or tensile deformation of the display panel DP due to point impacts and surface impacts.

[0087] One or more functional layers FC may be provided between the display panel DP and the window module WM. According to an exemplary embodiment, the functional layer FC may include an anti-reflection layer that blocks reflection of external light. The anti-reflection layer may prevent the elements forming the display panel DP from being visible due to external light incident through the front surface of the display device DD. The anti-reflection layer may include a polarizing film and / or a phase delay film. The number of phase delay films and the phase delay length (λ / 4 or λ / 2) of the phase delay film may be determined according to the working principle of the anti-reflection layer.

[0088] The functional layer FC may further include sensing user input TC (see Figure 1 ) of the input sensing layer. The input sensing layer may be provided as a separate layer with respect to the display panel DP and may be coupled by an adhesive layer. In another exemplary embodiment, the input sensing layer may be integrated with the display panel DP by at least one continuous process. More specifically, the input sensing layer may be directly disposed on the encapsulation layer of the display panel DP. As used herein, the term "directly" disposed may refer to an input sensing layer being disposed on the display panel DP without using a separate adhesive member. In an exemplary embodiment, the input sensing layer is disposed on the top surface of the display panel DP, but is not limited thereto. In another exemplary embodiment, the input sensing layer may be disposed on the rear surface of the display panel.

[0089] The window module WM and the functional layer FC may be adhered to each other through the first adhesive layer AL1. The display panel DP and the functional layer FC may be adhered to each other through the second adhesive layer AL2.

[0090] The first adhesive layer AL1 and the second adhesive layer AL2 may be optically transparent, respectively. Each of the first adhesive layer AL1 and the second adhesive layer AL2 may be an adhesive layer prepared by applying and curing a liquid adhesive material, or may be an adhesive sheet prepared separately. For example, each of the first adhesive layer AL1 and the second adhesive layer AL2 may be a pressure-sensitive adhesive (PSA), an optically clear adhesive (OCA), or an optically clear resin (OCR).

[0091] The protective film PF may be disposed on the rear surface of the display panel DP. The protective film PF may include a polymer material. The protective film PF may be a layer for absorbing an impact applied from the outside to protect the display panel DP from the impact. The protective film PF may be attached to the rear surface of the display panel DP through the third adhesive layer AL3.

[0092] although Figure 4 The protective film PF is shown as being disposed on the rear surface of the display panel DP, but the inventive concept is not limited thereto. For example, in some exemplary embodiments, the display module DM may further include an upper protective film disposed between the display panel DP and the functional layer FC.

[0093] The material forming the protection film PF is not limited to the plastic resin and, therefore, may include an organic / inorganic composite material. The protection film PF may include a porous organic layer and an inorganic material filled in the pores of the organic layer.

[0094] exist Figure 5 In the display substrate DS shown in FIG. Figure 4 The protection film PF, the display panel DP, the functional layer FC, and the window module WM shown in FIG. 1 may be coupled to each other.

[0095] The display module DM may further include a flexible circuit board FCB connected to the display panel DP and a driving chip D-IC mounted on the flexible circuit board FCB. The flexible circuit board FCB may be connected to the main circuit board MCB.

[0096] Components such as a control chip, a plurality of passive elements, and a plurality of active elements may be mounted on the main circuit board MCB. The main circuit board MCB may be provided as a flexible film similar to the flexible circuit board FCB.

[0097] In the illustrated exemplary embodiment, the display module DM has a chip-on-film (COF) structure in which the driver chip D-IC is mounted on a flexible circuit board FCB. However, the inventive concept is not limited thereto. For example, the display module DM may have a chip-on-panel (COP) or chip-on-glass (COG) structure in which the driver chip D-IC is mounted on the display panel DP.

[0098] Fig. 6A is along Figure 5A cross-sectional view of the non-folding area taken along line II', and Figure 6B is along Figure 5 A cross-sectional view of the folding area taken along line II-II'.

[0099] Reference Fig. 6A and Figure 6B The window module WM may include a base layer WBS, a window module function layer WFC and a window module protection layer WPF. Figure 1 ) is stacked in sequence on the base layer WBS, the window module function layer WFC and the window module protection layer WPF.

[0100] The base layer WBS may include a transparent insulating material. The base layer WBS may be flexible. However, the inventive concept is not limited thereto. For example, in some exemplary embodiments, even when the base layer WBS is rigid, the base layer WBS may include a material that can be bent by controlling its thickness.

[0101] In an exemplary embodiment, the base layer WBS may include at least one of polyimide (PI), polyamideimide (PAI), polyetheretherketone (PEEK), polyetherimide (PEI), and thin-film glass. However, the inventive concept is not limited thereto, and the base layer WBS may include various other materials.

[0102] The window module functional layer WFC may be disposed on the base layer WBS. For example, the window module functional layer WFC may include at least one of an anti-fingerprint layer, an anti-reflection layer, an anti-glare layer, and a hard coating layer. The window module functional layer WFC may be provided on the top surface of the base layer WBS, that is, on the surface facing the user. The hard coating layer of the window module functional layer WFC is used to protect the base layer WBS from external impacts. The hard coating layer may have a press-fit hardness greater than the press-fit hardness of the base layer WBS. Therefore, the hard coating layer may include at least one of a polyurethane resin, an epoxy resin, an acrylic resin, and an acrylate resin.

[0103] The window module protection layer WPF is disposed on the window module functional layer WFC. The window module protection layer WPF may be a layer used to improve the impact resistance of the window module WM and prevent dispersion during breakage. Specifically, when the window module functional layer WFC includes a hard coating layer, the window module protection layer WPF may absorb external impacts and protect the hard coating layer from external impacts to improve the impact resistance of the window module functional layer WFC.

[0104] The window module protection layer WPF may include at least one selected from polyurethane resin, epoxy resin, polyester resin, polyether resin, acrylate resin, acrylonitrile-butadiene-styrene (ABS) resin and rubber. In an exemplary embodiment, the window module protection layer WPF may include at least one of phenylene, polyethylene terephthalate (PET), polyimide (PI), polyamide (PAI), polyethylene naphthalate (PEN) and polycarbonate (PC).

[0105] In an exemplary embodiment, an adhesive layer may be further disposed between the window module protection layer WPF and the window module functional layer WFC.

[0106] The first side surface WS1 on the first non-folding area NFA1 of the window module WM has a first surface roughness, and the second side surface WS2 on the folding area FA of the window module WM has a second surface roughness. Although not shown in the figure, in the second non-folding area NFA2 of the window module WM, the third side surface may have the same first surface roughness as the first side surface WS1. The second surface roughness is less than the first surface roughness. The first surface roughness may be defined as the average value of the height from the reference surface RS parallel to the third direction DR3 to the first side surface WS1 of the window module WM on the first non-folding area NFA1. The second surface roughness may be defined as the average value of the height from the reference surface RS to the second side surface WS2 of the window module WM on the folding area FA.

[0107] The first side surface WS1 of the window module WM may include a side surface WS11 of the base layer WBS, a side surface WS12 of the window module functional layer WFC, and a side surface WS13 of the window module protection layer WPF. When an adhesive layer is provided between the window module functional layer WFC and the window module protection layer WPF, the first side surface WS1 of the window module WM may further include a side surface of the adhesive layer.

[0108] The second side surface WS2 of the window module WM may include a side surface WS21 of the base layer WBS, a side surface WS22 of the window module functional layer WFC, and a side surface WS23 of the window module protection layer WPF. When an adhesive layer is provided between the window module functional layer WFC and the window module protection layer WPF, the second side surface WS2 of the window module WM may further include a side surface of the adhesive layer.

[0109] The first surface roughness of the first side surface WS1 of the window module WM can be defined as the average value of the heights from the side surface WS11 of the base layer WBS, the side surface WS12 of the window module functional layer WFC, and the side surface WS13 of the window module protection layer WPF to the reference surface RS. The second surface roughness of the second side surface WS2 of the window module WM can be defined as the average value of the heights from the side surface WS21 of the base layer WBS, the side surface WS22 of the window module functional layer WFC, and the side surface WS23 of the window module protection layer WPF to the reference surface RS.

[0110] Surface modification may occur on the first side surface WS1 of the window module WM by a laser process, which may be performed along a cutting line to complete the display module DM. In this case, the second surface roughness of the second side surface WS2 being less than the first surface roughness of the first side surface WS1 may indicate that the surface modification of the second side surface WS2 occurring on the folding area FA is smaller than the surface modification of the first side surface WS1 occurring on the first non-folding area NFA1. Specifically, this may mean that the stress and damage applied to the folding area FA during the laser process are relatively smaller than the stress and damage in the non-folding area NFA. As described above, since the stress and damage applied to the folding area FA are minimized during the processing, even if the folding operation is repeated on the folding area FA of the completed display device DD, defects such as cracks may be prevented or at least suppressed from occurring in the folding area FA.

[0111] Fig. 7A is along Figure 5 A cross-sectional view taken along line III-III'. Figure 7B It is shown Figure 5 A cross-sectional view of a state in which a portion of a display panel is bent.

[0112] Reference Figure 5 , Fig. 7A and Figure 7B , the display module DM may include a flexible display panel DP. Fig. 7A and Figure 7B , the display panel DP is exemplarily shown as a single layer. Although not shown in the drawings, the display panel DP may include a base layer, a circuit layer, a light emitting element layer, and an encapsulation layer.

[0113] The display panel DP may be divided into a bending area BA and a non-bending area NBA. The non-bending area NBA may be an area including the display area DA and the non-display area NDA of the display module DM. Also, a portion of the folding area FA, the first non-folding area NFA1, and the second non-folding area NFA2 of the display panel DP may be disposed on the non-bending area NBA, and another portion of the second non-folding area NFA2 may be disposed on the bending area BA. The bending area BA of the display panel DP may be bent toward the rear surface of the display panel DP at a predetermined curvature.

[0114] The bending area BA includes a curvature area CA and an opposing area FAA. The curvature area CA is an area adjacent to the non-bending area NBA and can be substantially bent. The opposing area FAA is adjacent to the curvature area CA and faces the non-bending area NBA in a bent state. The flexible circuit board FCB is connected to the opposing area FAA of the display panel DP.

[0115] The protective film PF may be provided to correspond to the non-bending area NBA and the opposing area FAA, and the protective film PF may not be provided on the curvature area CA. The bending opening portion OPP may be defined in the protective film PF to correspond to the curvature area CA. Since the protective film PF is removed from the curvature area CA, the stress generated in the curvature area CA may be reduced during bending. When the bending opening portion OPP is defined in the protective film PF according to an exemplary embodiment, the third adhesive layer AL3 may be removed in the bending opening portion OPP.

[0116] In another exemplary embodiment, the protection film PF may have a groove defined to correspond to the curvature area CA. More specifically, the protection film PF on the curvature area CA may have a thickness smaller than that of the protection film PF on the non-bending area NBA and the opposing area FAA.

[0117] FIG. 8A to FIG. 8D is a plan view illustrating a process of manufacturing a display panel according to an exemplary embodiment.

[0118] Reference FIG. 8A to FIG. 8D , prepare a mother substrate MS, and the mother substrate MS is divided into an active area AA and an inactive area NAA by using cutting lines as boundaries. The cutting lines may include first to fourth cutting lines CL1 to CL4. The mother substrate MS may be in Figure 4 A state in which each of the protection film PF, the display panel DP, the functional layer FC, and the window module WM are formed and coupled to each other is shown in FIG.

[0119] The first to fourth cutting lines CL1 to CL4 may have a closed curve shape, and a cutting process is sequentially performed along the first to fourth cutting lines CL1 to CL4 to form Figure 5 The display substrate DS includes only the active area AA and no invalid area NAA (see Fig.10 ).

[0120] In reference 8A to Fig.8D In the described exemplary embodiment, the mother substrate MS includes only one display substrate DS. However, in some exemplary embodiments, a plurality of display substrates may be simultaneously formed on the mother substrate MS, and a cutting process may be performed to form the plurality of display substrates.

[0121] Reference Fig. 8A, the first cutting line CL1 may be a path between a first starting point SP1 and a first end point EP1 disposed on the first non-folding area NFA1 in a path defining the active area AA. The first laser process may be performed using a first laser device LD1. The first laser process may include a process in which the first laser device LD1 is disposed on the rear surface of the mother substrate MS, and the first laser device LD1 moves along a first laser path LDL1, thereby irradiating a laser beam from the first starting point SP1 to the first end point EP1 along the first cutting line CL1.

[0122] The rear surface of the mother substrate MS may be defined as Figure 5 The display module DM provides a display surface IS (see Figure 1 ). The first starting point SP1 and the first end point EP1 may be disposed at a boundary between the first non-folding area NFA1 and the folding area FA. Also, the first starting point SP1 and the first end point EP1 may be exchanged with each other. That is, the first laser process may include a process of irradiating a laser beam from the first end point EP1 to the first starting point SP1 along the first cutting line CL1.

[0123] A portion of the inactive area NAA adjacent to the first non-folding area NFA1 may be removed by the first laser process. Here, the removed area may be defined as a first portion of the inactive area NAA.

[0124] Reference Figure 8B , a second laser process is performed along a second cutting line CL2 that is a path between a second start point SP2 and a second end point EP2 disposed on the second non-folding area NFA2 in a path defining the active area AA.

[0125] The second laser process may be performed using the same first laser device LD1 as the first laser process. The second laser process may include a process in which the first laser device LD1 is disposed on the rear surface of the mother substrate MS, and the first laser device LD1 moves along a second laser path LDL2 to irradiate a laser beam from a second starting point SP2 to a second end point EP2 along a second cutting line CL2.

[0126] The second starting point SP2 and the second end point EP2 may be disposed at a boundary between the folding area FA and the second non-folding area NFA2. Also, the second starting point SP2 and the second end point EP2 may be exchanged with each other. That is, the second laser process may include a process of irradiating a laser beam from the second end point EP2 to the second starting point SP2 along the second cutting line CL2.

[0127] In an exemplary embodiment, the second cutting line CL2 includes, but is not limited to, a curve. In an exemplary embodiment, because Figure 5The bending area BA shown in FIG. 1 has a shape protruding from the non-bending area NBA, so the second cutting line CL2 includes a curve. In another exemplary embodiment, the second cutting line CL2 may have a shape symmetrical to the first cutting line CL1. The shape and length of each of the first cutting line CL1 and the second cutting line CL2 may be variously changed according to the shape and length of the path defining the active area AA.

[0128] Reference Figure 8C , a third laser process is performed along a third cutting line CL3. The third cutting line CL3 is a path between a third starting point SP3 and a third end point EP3.

[0129] The third laser process may be performed using a second laser device LD2 different from the first laser device LD1 used in the first laser process and the second laser process. The third laser process may include a process in which the second laser device LD2 is disposed on the rear surface of the mother substrate MS, and the second laser device LD2 moves along a third laser path LDL3 to irradiate a laser beam from a third starting point SP3 to a third end point EP3 along a third cutting line CL3.

[0130] The third starting point SP3 may be disposed on the first non-folding area NFA1, and the third end point EP3 may be disposed on the second non-folding area NFA2. Moreover, the third starting point SP3 and the third end point EP3 may be exchanged with each other. That is, the third laser process may include a process of irradiating a laser beam from the third end point EP3 to the third starting point SP3 along the third cutting line CL3.

[0131] In an exemplary embodiment, a first end of the third cut line CL3 overlaps the first cut line CL1 , and a second end of the third cut line CL3 overlaps the second cut line CL2 .

[0132] Reference Fig.8D , a fourth laser process is performed along a fourth cutting line CL4. The fourth cutting line CL4 is a path between a fourth starting point SP4 and a fourth end point EP4.

[0133] The fourth laser process may be performed using the second laser device LD2 used in the third laser process. The fourth laser process may include a process in which the second laser device LD2 is disposed on the rear surface of the mother substrate MS, and the second laser device LD2 moves along a fourth laser path LDL4 to irradiate a laser beam from a fourth starting point SP4 to a fourth end point EP4 along a fourth cutting line CL4.

[0134] The fourth starting point SP4 may be disposed on the first non-folding area NFA1, and the fourth end point EP4 may be disposed on the second non-folding area NFA2. Moreover, the fourth starting point SP4 and the fourth end point EP4 may be exchanged with each other. That is, the fourth laser process may include a process of irradiating a laser beam from the fourth end point EP4 to the fourth starting point SP4 along the fourth cutting line CL4.

[0135] In an exemplary embodiment, a first end of the fourth cut line CL4 overlaps the first cut line CL1 , and a second end of the fourth cut line CL4 overlaps the second cut line CL2 .

[0136] In this way, the mother substrate MS can be cut into Figure 5 The shape of the display substrate DS shown in FIG. 1 is applied to the actual display device DD through the first to fourth laser processes.

[0137] Each of the first laser process and the second laser process may be defined as a high-energy laser process, and each of the third laser process and the fourth laser process may be defined as a low-energy laser process. More specifically, the second laser device LD2 used in the third laser process and the fourth laser process may irradiate a laser beam having lower energy than the energy of the first laser device LD1 used in the first laser process and the second laser process.

[0138] Each of the first laser process and the second laser process may include a process of repeatedly irradiating the laser beam N times. Each of the third laser process and the fourth laser process may include a process of repeatedly irradiating the laser beam M times. M may have a value in the range of about 3N to about 3.5N. That is, the number of laser irradiations in each of the third laser process and the fourth laser process may be greater than the number of laser irradiations in each of the first laser process and the second laser process.

[0139] In each of the first laser process and the second laser process, the first laser device LD1 may irradiate the laser beam at a first rate, and in each of the third laser process and the fourth laser process, the second laser device LD2 may irradiate the laser beam at a second rate. The first rate may be different from the second rate. For example, the second rate may be greater than the first rate.

[0140] Although the first laser device LD1 is described as being used in the first laser process and the second laser process, and the second laser device LD2 different from the first laser device LD1 is described as being used in the third laser process and the fourth laser process, in the laser process, the inventive concept is not limited thereto. For example, in some exemplary embodiments, the same laser device may be used for each of the first to fourth laser processes, but the energy of the laser beam used in each of the first to fourth laser processes may be set differently.

[0141] As described above, in the laser process of cutting the mother substrate MS, the first non-folding area NFA1 and the second non-folding area NFA2 may be cut by using a high-energy laser, and the folding area FA may be cut by using a low-energy laser. In this way, the stress applied to the second side surface WS2 of the folding area FA during the cutting process and the damage to the second side surface WS2 may be reduced. Therefore, defects such as cracks due to stress applied to the second side surface WS2 and damage to the second side surface WS2 caused by repeated folding operations may be reduced, which may improve the reliability of the foldable display device.

[0142] Fig. 9 It is shown as an example FIG. 8A to FIG. 8D A view of the first starting point to the fourth starting point and the first end point to the fourth end point on the mother substrate.

[0143] Reference Fig. 9 , the first starting point SP1 and the first end point EP1 may be set at the boundary between the first non-folding area NFA1 and the folding area FA. The second starting point SP2 and the second end point EP2 may be set at the boundary between the folding area FA and the second non-folding area NFA2. The third starting point SP3 may be set on the first non-folding area NFA1, and the third end point EP3 may be set on the second non-folding area NFA2. The fourth starting point SP4 may be set on the first non-folding area NFA1, and the fourth end point EP4 may be set on the second non-folding area NFA2.

[0144] More specifically, the first starting point SP1 and the third starting point SP3 are disposed on a portion of the first cutting line CL1 extending in the first direction DR1. The second end point EP2 and the third end point EP3 are disposed on a portion of the second cutting line CL2 extending in the first direction DR1. The fourth starting point SP4 and the first end point EP1 are disposed on a portion of the first cutting line CL1 extending in the first direction DR1. The second starting point SP2 and the fourth end point EP4 are disposed on a portion of the second cutting line CL2 extending in the first direction DR1.

[0145] In the first laser process, Fig. 8A The first cutting line CL1 between the first starting point SP1 and the first end point EP1 shown in FIG. 1 may be processed by the first laser device LD1. In this case, the first laser device LD1 may have a first energy level E1.

[0146] In the second laser process, Figure 8B The second cutting line CL2 between the second starting point SP2 and the second end point EP2 shown in FIG. 4 may be processed by the first laser device LD1. In this case, the first laser device LD1 may have the same first energy level E1 as the first laser process.

[0147] In the third laser process, Figure 8C The third cutting line CL3 between the third starting point SP3 and the third end point EP3 shown in FIG. 1 may be processed by the second laser device LD2. Here, the second laser device LD2 between the third starting point SP3 and the first starting point SP1 in the third cutting line CL3 may have a third energy level E3.

[0148] Here, the second laser device LD2 between the first starting point SP1 and the second end point EP2 in the third cutting line CL3 may have a second energy level E2. Also, in the third cutting line CL3, the second laser device LD2 between the second end point EP2 and the third end point EP3 may have a third energy level E3. That is, in the third laser process, the laser power of the second laser device LD2 sequentially changes from the third energy level E3 to the second energy level E2 along the first direction D1, and then returns to the third energy level E3. The magnitude of the first energy level E1 to the third energy level E3 can be expressed as follows: E1>E2>E3.

[0149] A first end of the third cutting line CL3, for example, a portion between the third starting point SP3 and the first starting point SP1, overlaps with the first cutting line CL1, and a second end of the third cutting line CL3, for example, a portion between the second end point EP2 and the third end point EP3, overlaps with the second cutting line CL2. Therefore, each laser process can be performed twice.

[0150] Therefore, laser processing may be performed at the third energy level (lowest energy level) E3 between the third starting point SP3 and the first starting point SP1 and between the second end point EP2 and the third end point EP3 to prevent excessive laser processing.

[0151] If the third starting point SP3 of the third laser process is the same as the point where the folding area FA starts (ie, the first starting point SP1), the laser beam applied to the second side surface WS2 (see FIG. Figure 6B ) may increase, which may damage the second side surface WS2. In an exemplary embodiment, the third starting point SP3 may be placed at any position on the first cutting line CL1 of the first non-folding area NFA1 to minimize the stress applied to the second side surface WS2 of the folding area FA (see Figure 6B ) to prevent or at least inhibit damage to it during manufacturing.

[0152] In the third laser process, Fig.8D The fourth cutting line CL4 between the fourth starting point SP4 and the fourth end point EP4 shown in FIG. 4 may be performed by the second laser device LD2. Here, the second laser device LD2 between the fourth starting point SP4 and the first end point EP1 in the fourth cutting line CL4 may have a third energy level E3.

[0153] Furthermore, the second laser device LD2 between the first end point EP1 and the second start point SP2 in the fourth cutting line CL4 may have a second energy level E2. Furthermore, the second laser device LD2 between the second start point SP2 and the fourth end point EP4 in the fourth cutting line CL4 may have a third energy level E3. That is, in the fourth laser process, the laser power of the second laser device LD2 is sequentially changed from the third energy level E3 to the second energy level E2, and then back to the third energy level E3. The magnitude of the first energy level E1 to the third energy level E3 can be expressed as follows: E1>E2>E3.

[0154] The first end of the fourth cutting line CL4, for example, a portion between the fourth starting point SP4 and the first end point EP1, overlaps with the first cutting line CL1; and the second end of the fourth cutting line CL4, for example, a portion between the second starting point SP2 and the fourth end point EP4, overlaps with the second cutting line CL2. Therefore, each laser process can be performed twice.

[0155] Therefore, laser processing may be performed at the third energy level (lowest energy level) E3 between the fourth starting point SP4 and the first end point EP1 and between the second starting point SP2 and the fourth end point EP4 to prevent excessive laser processing.

[0156] Fig.10 is a view of a mother substrate according to another exemplary embodiment.

[0157] Fig.10 The mother substrate MS has Fig. 9 The structure of the mother substrate MS is similar to that of the mother substrate MS. Fig.10 The parent substrate MS and Fig. 9 The mother substrate MS is different in positions of a third starting point SP3 and a third end point EP3 of the third cutting line CL3 and positions of a fourth starting point SP4 and a fourth end point EP4 of the fourth cutting line CL4.

[0158] More specifically, when Fig. 9 When comparing, Fig.10 The third starting point SP3 of the third cutting line CL3 and the fourth starting point SP4 of the fourth cutting line CL4 shown in FIG. 4 may be disposed further away from the folding area FA in the direction opposite to the first direction DR1. Fig. 9 When comparing, Fig.10 The third end point EP3 of the fourth cutting line CL4 and the fourth end point EP4 of the fourth cutting line CL4 shown in FIG. 4 may be disposed further away from the folding area FA in the first direction DR1.

[0159] As described above, the positions of the third start point SP3 and the third end point EP3 of the third cut line CL3 and the fourth start point SP4 and the fourth end point EP4 of the fourth cut line CL4 may be set at any position of the first and second cut lines CL1 and CL2 in the first direction D1.

[0160] Laser treatment may be performed at a third energy level (lowest energy level) E3 between the third starting point SP3 and the first starting point SP1 and between the second end point EP2 and the third end point EP3 to prevent excessive laser treatment. Also, laser treatment may be performed at a third energy level (lowest energy level) E3 between the fourth starting point SP4 and the first end point EP1 and between the second starting point SP2 and the fourth end point EP4 to prevent excessive laser treatment.

[0161] FIG. 11A to FIG. 11E Shows the settings in Fig.10 Photographs of the side surfaces of the display substrates on areas A1, A2, A3, A4 and A5.

[0162] FIG. 11A to FIG. 11E The side surface of the display substrate DS is shown. FIG. 8A to FIG. 8D The described first to fourth laser processes remove the ineffective area NAA and provide only the effective area AA on the display substrate DS.

[0163] Reference Fig.11A In the first area A1 disposed on the first non-folding area NFA1, the side surface of the display substrate DS has a first width range W1 from the reference line RL. The first width range W1 is defined as the maximum value of the distance from the reference line RL to the side surface of the display substrate DS in the second direction DR2. In the first area A1, the side surface of the display substrate DS is substantially parallel to the reference line RL.

[0164] Reference Fig. 11B In the second area A2 disposed on the first non-folding area NFA1, the side surface of the display substrate DS has a second width range W2 from the reference line RL. The second width range W2 is defined as the maximum value of the distance from the reference line RL to the side surface of the display substrate DS in the second direction DR2. In an exemplary embodiment, the second width range W2 is about 10.15 μm.

[0165] When the general Fig.11A and Fig. 11BWhen compared to each other, the second width range W2 on the second area A2 is greater than the first width range W1 on the first area A1. Since the laser process is performed twice, for example, the first laser process and the third laser process are performed between the third starting point SP3 and the first starting point SP1, the laser process may be excessive to some extent. However, since the third starting point SP3 and the first starting point SP1 are set in the first non-folding area NFA1 instead of the folding area FA, even when the folding operation is repeated in the folding area FA of the completed display device DD (see FIG. 2A to FIG. 3B ), defects such as cracks can be prevented from occurring in the folding area FA.

[0166] Reference Fig. 11C In the third area A3 disposed on the second non-folding area NFA2, the side surface of the display substrate DS has a third width range W3 from the reference line RL. The third width range W3 is defined as the maximum value of the distance from the reference line RL to the side surface of the display substrate DS in the second direction DR2. In an exemplary embodiment, the third width range W3 is about 12.03 μm.

[0167] When the general Fig.11A and Fig. 11C When compared to each other, the third width range W3 on the third area A3 is greater than the first width range W1 on the first area A1. Since the laser process is performed twice, for example, the second laser process and the third laser process are performed between the second end point EP2 and the third end point EP3, the laser process may be excessive to some extent. However, since the second end point EP2 and the third end point EP3 are set in the second non-folding area NFA2 instead of the folding area FA, even when the folding operation is repeated in the folding area FA of the completed display device DD (see FIG. 2A to FIG. 3B ), defects such as cracks can be prevented from occurring in the folding area FA.

[0168] Reference Fig.11D In the fourth area A4 disposed on the first non-folding area NFA1, the side surface of the display substrate DS has a fourth width range W4 from the reference line RL. The fourth width range W4 is defined as the maximum value of the distance from the reference line RL to the side surface of the display substrate DS in the second direction DR2. In an exemplary embodiment, the fourth width range W4 is about 12.08 μm.

[0169] When the general Fig.11A and Fig.11DWhen compared to each other, the fourth width range W4 on the fourth area A4 is greater than the first width range W1 on the first area A1. Since the laser process is performed twice, for example, the first laser process and the fourth laser process are performed between the fourth starting point SP4 and the first end point EP1, the laser process may be excessive to some extent. However, since the fourth starting point SP4 and the first end point EP1 are disposed in the first non-folding area NFA1 instead of the folding area FA, even when the folding operation is repeated in the folding area FA of the completed display device DD (see FIG. 2A to FIG. 3B ), defects such as cracks can be prevented from occurring in the folding area FA.

[0170] Reference Fig.11E , in the fifth area A5 disposed on the second non-folding area NFA2, the side surface of the display substrate DS has a fifth width range W5 from the reference line RL. The fifth width range W5 is defined as the maximum value of the distance from the reference line RL to the side surface of the display substrate DS in the second direction DR2. In an exemplary embodiment, the fifth width range W5 is about 13.05 μm.

[0171] When the general Fig.11A and Fig.11E When compared to each other, the fifth width range W5 on the fifth area A5 is greater than the first width range W1 on the first area A1. Since the laser process is performed twice, for example, the second laser process and the fourth laser process are performed between the second starting point SP2 and the fourth end point EP4, the laser process may be excessive to some extent. However, the second starting point SP2 and the fourth end point EP4 are set in the second non-folding area NFA2 instead of the folding area FA, even when the folding operation is repeated in the folding area FA of the completed display device DD (see FIG. 2A to FIG. 3B ), defects such as cracks can be prevented from occurring in the folding area FA.

[0172] In the display device having such a configuration, when a laser process of cutting the display substrate is performed, the laser process can be performed on a cutting line provided on the folding region, unlike in the non-folding region, by using a low-energy laser.

[0173] In this way, the stress applied to the side surface of the folding area and the damage to the side surface of the folding area can be reduced during the cutting process. As a result, defects on the folding area can be reduced to improve the product reliability of the foldable display device.

[0174] Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Therefore, the inventive concept is not limited to such embodiments, but is limited to the broader scope of the present disclosure and to various obvious modifications and equivalent arrangements apparent to those of ordinary skill in the art.

Claims

1. A method for manufacturing a display device, the display device comprising: A display panel having a folding area configured to be folded along a virtual folding axis, and a first non-folding area and a second non-folding area adjacent to both sides of the folding area; and a window disposed on the display panel and configured to be folded together with the display panel, wherein the method comprises: preparing a mother substrate, wherein the mother substrate has an effective area and an ineffective area divided by a cutting line as a boundary; performing a first laser process along a first cutting line of the cutting line disposed in the first non-folding area; performing a second laser process along a second cutting line of the cutting line disposed in the second non-folding area; and performing a third laser process along a third cutting line of the cutting line disposed in the folding area, in: A first end of the third cutting line overlaps with a first end of the first cutting line; and The second end of the third cutting line overlaps with the first end of the second cutting line.

2. The method according to claim 1, wherein: The third laser process is performed by irradiating a second laser beam having energy smaller than that of a first laser beam used in the first laser process.

3. The method according to claim 2, wherein: irradiating the first laser beam at a first rate in the first laser process; and In the third laser process, the second laser beam is irradiated at a second rate greater than the first rate.

4. The method according to claim 2, wherein: The second laser process is performed by irradiating the first laser beam.

5. The method according to claim 1, wherein: The first cutting line includes a first starting point and a first end point; The second cutting line includes a second starting point and a second end point; as well as The third cutting line includes a third starting point and a third end point.

6. The method according to claim 5, wherein: The third starting point of the third cutting line is arranged on the first cutting line; and The third end point of the third cutting line is disposed on the second cutting line.

7. The method according to claim 6, wherein: The third laser process starts at the third starting point of the third cutting line and ends at the third ending point of the third cutting line while passing through the first starting point of the first cutting line and the second ending point of the second cutting line.

8. The method according to claim 7, wherein: performing each of the first laser process and the second laser process by irradiating a first laser beam having a first energy level; The third laser process includes: In a first sub-laser process, a second laser beam having a third energy level is irradiated from the third starting point of the third cutting line to the first starting point of the first cutting line; a second sub-laser process, irradiating the second laser beam having the third energy level from the first starting point of the first cutting line to the second end point of the second cutting line; and In a third sub-laser process, the second laser beam having a second energy level is irradiated from the second end point of the second cutting line to the third end point of the third cutting line; and the first energy level, the second energy level and the third energy level have different laser powers from each other.

9. The method according to claim 8, wherein: The first energy level is greater than the second energy level; and The second energy level is greater than the third energy level.

10. The method of claim 1, wherein: The method further includes performing a fourth laser process along a fourth cutting line of the cutting line disposed in the folding area, in: A first end of the fourth cutting line overlaps with a second end of the first cutting line; and A second end of the fourth cutting line overlaps with a second end of the second cutting line.

11. The method according to claim 10, wherein: The fourth starting point of the fourth cutting line is arranged on the first cutting line; and The fourth end point of the fourth cutting line is arranged on the second cutting line.

12. The method according to claim 11, wherein: performing each of the first laser process and the second laser process by irradiating a first laser beam having a first energy level; as well as The fourth laser process is performed by irradiating a second laser beam having energy smaller than that of the first laser beam.

13. The method of claim 10, wherein: The first cutting line to the fourth cutting line form a closed curve shape surrounding the effective area; as well as After performing the first to fourth laser processes along the first to fourth cutting lines, the ineffective region of the mother substrate is removed.

14. A display device, comprising: a display panel configured to display an image and comprising a folding area configured to be folded along a virtual folding axis and a non-folding area adjacent to one side of the folding area; as well as a window disposed on the display panel and comprising a soft material such that the window is configured to be folded together with the display panel; in: The non-folding area includes a first area and a second area sequentially arranged in a first direction, and the second area is arranged adjacent to the folding area; as well as A portion of the side surface of the window disposed in the first region has a first width range from a reference line parallel to a first direction, and a portion of the side surface of the window disposed in the second region has a second width range from the reference line different from the first width range.

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