Patent Publication Number: US-2021183277-A1

Title: Stretchable display panel and device and manufacturing method of the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/590,083, filed Oct. 1, 2019, which claims the priority of Korean Patent Application No. KR 1-2018-0119622, filed Oct. 08, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a stretchable display panel and device and a manufacturing method thereof and, in particular, a stretchable display panel and device that may reduce damage to wires even though it is bent or stretched, and a method of manufacturing the stretchable display device. 
     Description of the Related Art 
     An Organic Light Emitting Display (OLED) that generates light by itself, a Liquid Crystal Display (LCD) that requires separate light sources, etc., are used as the display devices of a computer monitor, a TV, a mobile phone, and the like. 
     Display devices are being applied to more and more various fields including not only a computer monitor and a TV, but personal mobile devices, a display device having a wide active area and reduced volume and weight is being studied. 
     Recently, a stretchable display device manufactured to be able to stretch/contract in a specific direction and change into various shapes by forming a display unit, lines, etc., on a flexible substrate such as plastic that is a flexible material has been spotlighted as a next generation display device. 
     BRIEF SUMMARY 
     An object of the present disclosure is to provide a stretchable display device that may be bent or stretched without damaging display elements disposed on a plurality of individual substrates on which a plurality of pixels is defined because a lower substrate disposed under the plurality of individual substrates has a modulus that is different for each area, and a method of manufacturing the stretchable display device. 
     Another object of the present disclosure is to provide a stretchable display device that may suppress damage to connecting lines due to a step because the connecting lines are disposed flat without a step under a lower substrate and the connecting lines and pads are electrically connected through contact holes formed at individual substrates and an insulating layer disposed under display elements, and a method of manufacturing the stretchable display device. 
     Objects of the present disclosure are not limited to the above-mentioned objects, and other objects, which are not mentioned above, can be clearly understood by those skilled in the art from the following descriptions. 
     According to an aspect of the present disclosure, there is provided a stretchable display panel, comprising: a lower substrate having an active area and a non-active area surrounding the active area; a plurality of individual substrates disposed on the lower substrate and located in the active area; a plurality of pixels disposed on the plurality of individual substrates; and a connection line disposed between the plurality of individual substrates and the lower substrate, wherein the elastic modulus of the plurality of individual substrates is higher than that of at least one part of the lower substrate, and wherein the connecting line extends to the bottom surface of the individual substrates, such that the connection line has the same height for its entire length above the lower substrate and therefore electrically connects a pad disposed on the individual substrates without a step in the top surface of the connecting line. 
     According to another aspect of the present disclosure, there is provided a stretchable display device comprising the above stretchable display panel. 
     According to another aspect of the present disclosure, there is provided a method of manufacturing a stretchable display device, the method comprising: disposing a plurality of individual substrates on a temporary substrate; forming a transistor and a emitting element on one surface of the plurality of individual substrates; disposing a protective film on the emitting element and removing the temporary substrate; forming a first connecting line and a second connecting line, which are respectively electrically connected with a gate pad and a data pad, on another surface of the plurality of individual substrates; and forming a lower substrate including a first lower pattern overlapped with the plurality of individual substrates and a second lower pattern surrounding the first lower pattern, wherein the forming a first connecting line and a second connecting line is forming a connecting line having a flat surface for its entire length, and therefore being without a step. 
     Other detailed matters of the exemplary embodiments are included in the detailed description and the drawings. 
     The present disclosure has an effect that efficiently uses the area of a stretchable display device and increases an aperture ratio by disposing additional subpixels in the other area excepting a light emitting area and a line area on a lower substrate. 
     The present disclosure has an effect to be more easily bent or stretched by disposing a plurality of rigid patterns and flexible patterns excepting the plurality of rigid patterns under a plurality of individual substrates. The present disclosure has an effect to minimize damage to the connecting line due to a step generated in the connecting line. 
     The effects according to the present disclosure are not limited to the contents exemplified above, and more various effects are included in the present specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view of a stretchable display device according to an embodiment of the present disclosure; 
         FIG. 2  is an enlarged plan view of the stretchable display device according to an embodiment of the present disclosure. 
         FIG. 3  is a schematic cross-sectional view showing one subpixel shown in  FIG. 1 ; 
         FIG. 4A to 4G  are process cross-sectional views illustrating a method of manufacturing a stretchable display device according to an embodiment of the present disclosure; 
         FIG. 5  is a schematic cross-sectional view showing one subpixel of a stretchable display device according to another embodiment of the present disclosure; 
         FIG. 6A to 6G  are process cross-sectional views illustrating a method of manufacturing a stretchable display device according to another embodiment of the present disclosure; 
         FIG. 7  is a partially enlarged plan view of the stretchable display device according to still another embodiment of the present disclosure; 
         FIG. 8  is a schematic cross-sectional view showing one subpixel of a stretchable display device according to still another embodiment of the present disclosure; and 
         FIG. 9  is a schematic cross-sectional view showing one subpixel of a stretchable display device according to still another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     Advantages and characteristics of the present disclosure and a method of achieving the advantages and characteristics will be clear by referring to exemplary embodiments described below in detail together with the accompanying drawings. 
     However, the present disclosure is not limited to the exemplary embodiments disclosed herein but will be implemented in various forms. The exemplary embodiments are provided by way of example only so that those skilled in the art can fully understand the disclosures of the present disclosure and the scope of the present disclosure. Therefore, the present disclosure will be defined only by the scope of the appended claims. 
     The shapes, sizes, ratios, angles, numbers, and the like illustrated in the accompanying drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. Like reference numerals generally denote like elements throughout the specification. Further, in the following description of the present disclosure, a detailed explanation of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of the present disclosure. The terms such as “including,” “having,” and “consist of” used herein are generally intended to allow other components to be added unless the terms are used with the term “only.” Any references to singular may include plural unless expressly stated otherwise. 
     Components are interpreted to include an ordinary error range even if not expressly stated. 
     When the position relation between two parts is described using the terms such as “on,” “above,” “below,” and “next,” one or more parts may be positioned between the two parts unless the terms are used with the term “immediately” or “directly.” 
     When an element or layer is disposed “on” another element or layer, another layer or another element may be interposed directly on the other element or therebetween. 
     Although the terms “first,” “second,” and the like are used for describing various components, these components are not confined by these terms. These terms are merely used for distinguishing one component from the other components. Therefore, a first component to be mentioned below may be a second component in a technical concept of the present disclosure. 
     Like reference numerals generally denote like elements throughout the specification. 
     A size and a thickness of each component illustrated in the drawing are illustrated for convenience of description, and the present disclosure is not limited to the size and the thickness of the component illustrated. 
     The features of various embodiments of the present disclosure can be partially or entirely adhered to or combined with each other and can be interlocked and operated in technically various ways, and the embodiments can be carried out independently of or in association with each other. 
     Hereinafter, a stretchable display device and manufacturing method of the same according to exemplary embodiments of the present disclosure will be described in detail with reference to accompanying drawings. 
     Stretchable Display Device 
     A stretchable display device may be referred to as a display device that may display images even if it is bent or stretched. A stretchable display device may have high flexibility, as compared with common display devices. Accordingly, the shape of the stretchable display device may be freely changed in accordance with operation by a user such as bending or stretching the stretchable display device. For example, when a user holds and pulls an end of a stretchable display device, the stretchable display device may be stretched by the force of the user. Alternatively, when a user puts a stretchable display device on an uneven wall, the stretchable display device may be bent into the surface shape of the wall. When the force applied by a user is removed, a stretchable display device may return into the initial shape. 
       FIG. 1  is an exploded perspective view of a stretchable display device according to an embodiment of the present disclosure. Referring to  FIG. 1 , a stretchable display device  100  includes a lower substrate  110 , a plurality of individual substrates  111 , connecting lines  180 , Chip on Films (COF)  130 , a printed circuit board  140 , an upper substrate  120 , and a polarizing layer  190 . An adhesive layer for bonding the lower substrate  110  and the upper substrate  120  is not shown in  FIG. 1  for the convenience of description. 
     The lower substrate  110  is a substrate for supporting and protecting various components of the stretchable display device  100 . The lower substrate  110 , which is a flexible substrate, may be made of a bendable or stretchable insulating material. For example, the lower substrate  110  may be made of silicon rubber such as polyimethylsiloxane (PDMS) or an elastomer such as polyurethane (PU), so it may have flexibility. The material of the lower substrate  110 , however, is not limited thereto. 
     The lower substrate  110 , which is a flexible substrate, may reversibly expand and contract. The lower substrate  110  may have an elastic modulus of several to hundreds of MPa and a tensile fracture rate of 100% or more. The elastic modulus may be referred to herein either as the elastic modulus or in some instances, as the modulus. The thickness of the lower substrate  110  may be 10 μm to 1 mm, but is not limited thereto. 
     The lower substrate  110  is a flexible substrate and may further include a rigid pattern made of a material that is more rigid than a flexible substrate. That is, the lower substrate  110  may include a first lower pattern and a second lower pattern that are different in modulus. For example, the first lower pattern may be higher in modulus than the second lower pattern and the second lower pattern may be lower in modulus than the first lower pattern. The lower substrate  110  will be described below in more detail with reference to  FIG. 3 . 
     The lower substrate  110  may have an active area AA and a non-active area NA surrounding the active area AA. 
     The active area AA is an area where images are displayed on the stretchable display device  100 , and light emitting elements and various driving elements for driving the light emitting elements are disposed in the active area AA. The active area AA includes a plurality of pixels including a plurality of subpixels. The plurality of pixels is disposed in the active area AA and includes a plurality of subpixels. The plurality of subpixels each may be connected with various lines. For example, the plurality of subpixels each may be connected with various lines such as a gate line, a data line, a high-potential power line, a low-potential power line, and a reference voltage line. 
     The non-active area NA is an area adjacent to the active area AA. The non-active area NA is an area disposed adjacent to the active area AA and surrounding the active area AA. The non-active area NA is an area where an image is not displayed, and lines and circuits may be disposed in the non-active area NA. For example, a plurality of pads may be disposed in the non-active area NA and the pads may be respectively connected with the plurality of subpixels in the active area AA. 
     A plurality of individual substrates  111  is disposed in the area overlapped with the first lower pattern of the lower substrate  110 . The plurality of individual substrates  111 , which are rigid substrates, is spaced apart from each other. The plurality of individual substrates  111  may be more rigid than the second lower pattern of the lower substrate  110 . 
     The plurality of individual substrates  111 , which is a plurality of rigid substrates, may be made of plastic having flexibility and, for example, may be made of Polyimide (PI), polyacrylate, or polyacetate. 
     The modulus of the plurality of individual substrates  111  may be higher than that of the second lower pattern of the lower substrate  110 . The modulus is an elastic modulus showing the ratio of deformation of a substrate to stress applied to the substrate, and when the modulus is relatively high, the strength may be relatively high. Accordingly, the plurality of individual substrates  111  may be the plurality of rigid substrates that is more rigid than the lower substrate  110 . The modulus of the plurality of individual substrates  111  may be a thousand times larger than that of the lower substrate  110 , but is not limited thereto. 
     Connecting lines  180  are disposed under the plurality of individual substrates  111  and on the lower substrate  110 . That is, the connecting lines  180  may be disposed between the plurality of individual substrates  111  and the lower substrate  110 . The connecting lines  180  may be electrically connected with pixels through contact holes formed at the plurality of individual substrates  111  and insulating layers under the light emitting elements disposed on the individual substrates  111 . The connecting lines  180  will be described below in more detail with reference to  FIGS. 2 and 3 . 
     The COFs  130 , which are films having various components on flexible base films  131 , are components for supplying signals to the plurality of subpixels in the active area AA. The COFs  130  may be bonded to the plurality of pads disposed in the non-active area NA and supply a power voltage, a data voltage, a gate voltage, etc., to the plurality of subpixels in the active area AA through the pads. The COFs  130  each include a base film  131  and a driving IC  132  and may include various other components. 
     The base films  131  are layers supporting the driving ICs  132  of the COFs  130 . The base films  131  may be made of an insulating material, for example, an insulating material having flexibility. 
     The driving ICs  132  are components that process data for displaying images and driving signals for processing the data. Although the driving ICs  132  are mounted in the type of the COF  130  in  FIG. 1 , the driving ICs  132  are not limited thereto and may be mounted in the type of Chip On Glass (COG) or Tape Carrier Package (TCP). 
     Controllers such as an IC chip and a circuit may be mounted on the printed circuit board  140 . A memory, a processor, etc., may also be mounted on the printed circuit board  140 . The printed circuit board  140  transmits signals for driving the pixels from the controller to the pixels. 
     The printed circuit board  140  is connected with the COFs  130 , so they may be electrically connected with the plurality of subpixels on the plurality of individual substrates  111 . 
     The upper substrate  120  is a substrate overlapped over the lower substrate  110  to protect various components of the stretchable display device  100 . The upper substrate  120 , which is a flexible substrate, may be made of a bendable or stretchable insulating material. For example, the upper substrate  120  may be made of a flexible material and may be made of the same material the lower substrate  110 , but is not limited thereto. 
     The polarizing layer  190 , which is a component reducing external light reflection by the stretchable display device  100 , may be disposed on the upper substrate  120  so as to overlap the upper substrate  120 . However, the polarizing layer  190  is not limited thereto and, may be disposed under the upper substrate  120 , or may not be provided, depending on the configuration of the stretchable display device  100 . 
       FIGS. 2 and 3  are referred to hereafter to describe in more detail the stretchable display device  100  according to an embodiment of the present disclosure. 
     Planar &amp; Cross-Sectional Structure 
       FIG. 2  is an enlarged plan view of the stretchable display device according to an embodiment of the present disclosure.  FIG. 3  is a schematic cross-sectional view showing one subpixel shown in  FIG. 1 . Pixels and corresponding subpixels having the same connecting lines and characteristics are positioned on each side of the pixel shown in  FIG. 3 , the pattern repeating itself numerous times on the display panel. Only a single pixel is shown for ease of reference.  FIG. 1  is referred to for the convenience of description. 
     Referring to  FIGS. 2 and 3 , the lower substrate  110  supporting components of the stretchable display device  100  is disposed. In more detail, referring to  FIG. 3 , the lower substrate  110  includes a plurality of first lower patterns  110 A and second lower patterns  110 B. 
     The plurality of first lower patterns  110 A is disposed in the areas overlapped with a plurality of individual substrates  111  on the lower substrate  110 . The plurality of first lower patterns  110 A may be disposed under the plurality of individual substrates  111  with the top surfaces bonded to the bottom surfaces of the plurality of individual substrates  111  by a lower adhesive layer  119 . 
     The second lower patterns  110 B are disposed in areas excepting the plurality of first lower patterns  110 A on the lower substrate  110 . The second lower patterns  110 B may be disposed to surround the sides and the bottom surface of the plurality of first lower pattern  110 A. However, the second lower patterns  110 B are not limited thereto and may be disposed in the same plane as the first lower patterns  110 A. The second lower patterns  110 B are disposed under the connecting lines  180  and a first adhesive layer  119  with the top surfaces in contact with the bottom surfaces of the connecting lines  180  and the bottom surface of the first adhesive layer  119 . 
     The first lower patterns  110 A may be larger in modulus than the second lower patterns  110 B. Accordingly, the plurality of first lower patterns  110 A may be a plurality of lower rigid patterns that is more rigid than the second lower patterns  110 B, and the second lower patterns  110 B may be flexible lower patterns that are more flexible than the plurality of first lower patterns  110 A. The modulus of the plurality of first lower patterns  110 A may be a thousand times larger than those of the second lower patterns  110 B, but is not limited thereto. 
     The plurality of first lower patterns  110 A may be made of the same material as the plurality of individual substrates  111 , may be made of plastic having flexibility, and for example, may be made of Polyimide (PI), polyacrylate, or polyacetate. However, the plurality of first lower patterns  110 A is not limited thereto and may be made of a material having a modulus that is the same as or smaller than those of the plurality of individual substrates  111 . 
     The second lower patterns  110 B, which are flexible lower patterns, may reversely expand and contract and may have an elastic modulus of several to hundreds of MPa and a tensile fracture rate of 100% or more. Accordingly, the second lower patterns  110 B may be made of a bendable or stretchable insulating material and may be made of silicon rubber such as Polydimethylsiloxane (PDMS) or an elastomer such as Polyurethane (PU), but are not limited thereto. 
     Referring to  FIGS. 2 and 3 , the plurality of individual substrates  111  is disposed on the lower substrate  110 . The plurality of individual substrates  111  is disposed in areas overlapped with the first lower patterns  110 A on the lower substrate  110 . The plurality of individual substrates  111  is spaced apart from each other on the lower substrate  110 . The distance between the plurality of individual substrates  111  and the distance between the plurality of first lower patterns  110 A of the lower substrate  110  may be the same. For example, the plurality of individual substrates  111  is spaced a predetermined distance apart from each other, so they may be disposed in a matrix shape on the lower substrate  110 , as shown in  FIGS. 1 and 2 , but is not limited thereto. 
     A contact hole CT for electrically connecting the connecting lines  180  disposed under the plurality of individual substrates  111 , and gate pads  171  and data pads  173  disposed on the plurality of individual substrates  111  may be formed at the plurality of individual substrates  111 . 
     Referring to  FIG. 3 , a buffer layer  112  is disposed on the plurality of individual substrates  111 . The buffer layer  112  is formed on the plurality of individual substrates  111  to protect various components of the stretchable display device  100  against permeation of water (H 2 O) and oxygen (O2) from the outside the lower substrate  110  and the plurality of individual substrates  111 . The buffer layer  112  may be made of an insulating material, and for example, may be a single inorganic layer or a multi-inorganic layer made of graphite, a silicon nitride (SiNx), a silicon oxide (SiOx), or silicon oxynitride (SiON). However, the buffer layer  112  may not be provided, depending on the structure of characteristics of the stretchable display device  100 . 
     The buffer layer  112  may be formed only in the areas overlapped with the plurality of individual substrates  111 . As described above, since the buffer layers  112  may be made of an inorganic material, they may be easily damaged, such as cracking, when the stretchable display device  100  is stretched. Accordingly, the buffer layer  112  is patterned in the shape of the plurality of individual substrates  111  without being formed in the areas between the plurality of individual substrates  111 , whereby it may be formed only on the plurality of individual substrates  111 . Therefore, since the buffer layer  112  is formed only in the areas overlapped with the plurality of individual substrates  111  that are rigid substrates, it is possible to reduce damage to the buffer layer  112  even though the stretchable display device  100  according to an embodiment of the present disclosure is deformed, such as bending or stretching. 
     A contact hole CT for electrically connecting the connecting lines  180  disposed under the plurality of individual substrates  111 , and the gate pads  171  and the data pads  173  disposed on the plurality of individual substrates  111  may be formed at the buffer layers  112 . The contact holes CT formed at the buffer layers  112  may extend from the contact holes CT formed at the plurality of individual substrates  111 . 
     Referring to  FIG. 3 , a transistor  150  including a gate electrode  151 , an active layer  152 , a source electrode  153 , and a drain electrode  154  is formed on the buffer layer  112 . For example, the active layer  152  is formed on the buffer layer  112 , and a gate insulating layer  113  for insulating the active layer  152  and the gate electrode  151  from each other is formed on the active layer  152 . An inter-layer insulating layer  114  is formed to insulate the gate electrode  151 , the source electrode  153 , and the drain electrode  154  from each other, and the source electrode  153  and the drain electrode  154  that are in contact with the active layer  152  are formed on the inter-layer insulating layer  114 . 
     The gate insulating layer  113  and the inter-layer insulating layer  114  may be formed only in the areas overlapped with the plurality of individual substrates  111  by patterning. The gate insulating layer  113  and the inter-layer insulating layer  114  may also be made of an inorganic material, similar to the buffer layer  112 , so they may be easily damaged such as cracking when the stretchable display device  100  is stretched. Accordingly, the gate insulating layer  113  and the inter-layer insulating layer  114  are patterned in the shape of the plurality of individual substrates  111  without being formed in the areas between the plurality of individual substrates  111 , whereby they may be formed only on the plurality of individual substrates  111 . 
     A contact hole CT for electrically connecting the connecting lines  180  disposed under the plurality of individual substrates  111 , and the gate pads  171  and the data pads  173  may be formed at the gate insulating layer  113  and the inter-layer insulating layer  114 . The contact holes CT formed at the gate insulating layer  113  and the inter-layer insulating layer  114  may extend from the contact holes CT formed at the plurality of individual substrates  111  and the buffer layer  112 . 
     Only a driving transistor of various transistors that may be included in the stretchable display device  100  is shown in  FIG. 3  for the convenience of description, but a switching transistor, a capacitor, etc., may be included in the display device. Further, although the transistor  150  is described as having a coplanar structure in the present disclosure, various transistors, for example, having a staggered structure may be used. 
     Referring to  FIG. 3 , a gate pad  171  is disposed on the gate insulating layer  113 . The gate pad  171  is a pad for transmitting a gate signal to a plurality of subpixels SPX. The gate pad  171  may be disposed on the same layer as the gate electrode  151  and made of the same material as the gate electrode  151 , but is not limited thereto. That is, the gate pad  171  may be made of the same material as at least one of conductive patterns of the transistor  150  and the organic light emitting element  160  disposed on the individual substrate  111 . For example, the gate pad  171  may be made of the same material as one of the gate electrode  151 , the source electrode  153 , the drain electrode  154 , and the anode  161  on the same layer. Alternatively, the gate pad  171  may be made of the same material as two of the gate electrode  151 , the source electrode  153 , the drain electrode  154 , and the anode  161  on the same layer. The gate pad  171  may be electrically connected with a first connecting line  181  that functions as a gate line disposed under the individual substrate  111  through contact holes CT formed at the individual substrate  111 , the buffer layer  112 , and the gate insulating layer  113 . 
     Referring to  FIG. 3 , a data pad  173  is disposed on the inter-layer insulating layer  114 . The data pad  173  may be electrically connected with a second connecting line  182  that functions as a data line, and may transmit a data signal from the second connecting line  182  to a plurality of subpixels SPX. The data pad  173  may be defined as an area where the source electrode  153  of the transistor  150  extends, but is not limited thereto. That is, the data pad  173  may be made of the same material as at least one of conductive patterns of the transistor  150  and the organic light emitting element  160  disposed on the individual substrate  111 . For example, the data pad  173  may be made of the same material as one of the gate electrode  151 , the source electrode  153 , the drain electrode  154 , and the anode  161  on the same layer. Alternatively, the data pad  173  may be made of the same material as two of the gate electrode  151 , the source electrode  153 , the drain electrode  154 , and the anode  161  on the same layer. The data pad  173  may be electrically connected with a second connecting line  182  that functions as a data line disposed under the individual substrate  111  through contact holes CT formed at the individual substrate  111 , the buffer layer  112 , the gate insulating layer  113 , and the inter-layer insulating layer  114 . 
     Referring to  FIG. 3 , a planarization layer  115  is formed on the transistor  150  and the inter-layer insulating layer  114 . The planarization layer  115  planarizes the top surface of the transistor  150 . The planarization layer  115  may be composed of a single layer or a plurality of layers and may be made of an organic material. For example, the planarization layer  115  may be made of an acrylic-based organic material, but is not limited thereto. The planarization layer  115  may have a contact hole for electrically connecting the transistor  150  and the anode  161 . 
     In some embodiments, a passivation layer may be formed between the transistor  150  and the planarization layer  115 . That is, a passivation layer covering the transistor  150  may be formed to protect the transistor  150  from permeation of water and oxygen. The passivation layer may be made of an inorganic material and may be composed of a single layer or a plurality of layers, but is not limited thereto. 
     Referring to  FIG. 3 , an organic light emitting element  160  is disposed on the planarization layer  115 . The organic light emitting elements  160  are components disposed to correspond to a plurality of subpixel SPX, respectively, and emit light having a specific wavelength band. That is, the organic light emitting element  160  may be a blue organic light emitting element that emits blue light, a red organic light emitting element that emits red light, a green organic light emitting element that emits green light, or a white organic light emitting element that emits white light, but is not limited thereto. When the organic light emitting element  160  is a white organic light emitting element, the stretchable display device  100  may further include a color filter. 
     The organic light emitting element  160  includes an anode  161 , an organic light emitting layer  162 , and a cathode  163 . In detail, the anode  161  is disposed on the planarization layer  115 . The anode  161  is an electrode for supplying holes to the organic light emitting layer  162 . The anode  161  may be made of a transparent conductive material with a high work function. The transparent conductive material may include an Indium Tin Oxide (ITO), an Indium Zinc Oxide (IZO), or an Indium Tin Zinc Oxide (ITZO). When the stretchable display device  100  is implemented in a top emission type, the anode  161  may further include a reflective plate. 
     The anodes  161  are spaced apart from each other respectively for subpixels SPX and electrically connected with the transistor  150  through contact holes of the polarization layer  115 . For example, although the anode  161  is electrically connected with the drain electrode  154  of the transistor  150  in  FIG. 3 , it may be electrically connected with the source electrode  153 . 
     A bank  116  is formed on the anode  161  and the planarization layer  115 . The bank  116  is a component separating adjacent subpixels SPX. The bank  116  is disposed to cover at least partially both sides of adjacent anodes  161 , thereby partially exposing the top surfaces of the anode  161 . The bank  116  may reduce the problem that an unexpected subpixel SPX emits light or colors are mixed by light emitted in the lateral direction of the anode  161  due to concentration of a current on the edge of the anode  161 . The bank  116  may be made of acrylic-based resin, Benzocyclobutene (BCB)-based resin, or polyimide, but is not limited thereto. 
     The organic light emitting layer  162  is disposed on the anode  161 . The organic light emitting layer  162  emits light. The organic light emitting layer  162  may include a luminescent material, and the luminescent material may include a phosphorous material or a fluorescent material, but is not limited thereto. 
     The organic light emitting layer  162  may be composed of one light emitting layer. Alternatively, the organic light emitting layer  162  may have a stacked structure in which a plurality of light emitting layers is stacked with charge generation layers therebetween. The organic light emitting layer  162  may further include at least one organic layer of a hole transporting layer, an electron transporting layer, a hole blocking layer, an electrode blocking layer, a hole injection layer, and an electron injection layer. 
     Referring to  FIGS. 2 and 3 , the cathode  163  is disposed on the organic light emitting layer  162 . The cathode  163  supplies electrons to the organic light emitting layer  162 . The cathode  163  may be made of Indium Tin Oxide (ITO)-based, Indium Tin Zinc Oxide (ITZO)-based, Zinc Oxide (ZnO)-based, or Tin Oxide (TO)-based transparent conductive oxides or a Ytterbium (Yb) alloy. Alternatively, the cathode  163  may be made of metal. 
     The cathodes  163  may be patterned to respectively overlap the plurality of individual substrates  111 . That is, the cathodes  163  may be disposed not in the areas between the plurality of individual substrates  111 , but only in the areas overlapped with the plurality of individual substrates  111 . Since the cathodes  163  are made of a transparent conductive oxide or metal, when the cathodes  163  are formed even in the areas between the plurality of individual substrates  111 , the cathodes  163  may be damaged when the stretchable display device  100  is stretched/contracted. Accordingly, the cathodes  163  may be formed to respectively correspond to the plurality of individual substrates  111 . Referring to  FIGS. 2 and 3 , the cathodes  163  may have an area not overlapped with the area where a connection line  180  is disposed, of the areas overlapped with the plurality of individual substrates  111 . 
     Referring to  FIGS. 2 and 3 , an encapsulation layer  117  is disposed on the organic light emitting element  160 . The encapsulation layer  117  may seal the organic light emitting element  160  by covering the organic light emitting element  160  in contact with a portion of the top surface of the bank  116 . Accordingly, the encapsulation layer  117  protects the organic light emitting element  160  from water, air, or physical shock that may be applied from the outside. 
     The encapsulation layers  117  respectively cover the cathodes  163  patterned to respectively overlap the plurality of individual substrate  111  and may be formed on the plurality of individual substrates  111 , respectively. That is, the encapsulation layers  117  are disposed to each cover one cathode  163  on one individual substrate  111  and the encapsulation layers  117  disposed on the plurality of individual substrates  111  may be spaced apart from each other. 
     The encapsulation layer  117  may be formed only in the areas overlapped with the plurality of individual substrates  111 . As described above, since the encapsulation layers  117  may include an inorganic layer, they may be easily damaged, such as cracking, when the stretchable display device  100  is stretched. In particular, since the organic light emitting element  160  is vulnerable to water or oxygen, when the encapsulation layer  117  is damaged, reliability of the organic light emitting element  160  may be reduced. Therefore, since the encapsulation layer  117  is not formed in the areas between the plurality of individual substrates  111 , damage to the encapsulation layer  117  may be minimized even though the stretchable display device  100  according to an embodiment of the present disclosure is deformed, such as, bending or stretching. 
     Compared with common flexible organic light emitting display devices of the related art, there is a difference in that the stretchable display device  100  according to an embodiment of the present disclosure has a structure in which the plurality of individual substrates  111  that is relatively rigid is disposed and spaced apart from each other on the lower substrate  110  that is relatively flexible. The cathodes  163  and the encapsulation layers  117  of the stretchable display device  100  are patterned to correspond to the plurality of individual substrates  111 , respectively. That is, the stretchable display device  100  according to an embodiment of the present disclosure may have a structure that enables the stretchable display device  100  to be more easily deformed when a user stretches or bends the stretchable display device  100  and that may minimize damage to the components of the stretchable display device  100  when the stretchable display device  100  is deformed. 
     In the stretchable display device  100  according to an embodiment of the present disclosure, the lower substrate  110  includes the first lower patterns  110 A overlapped with the plurality of individual substrates  111  and the second lower patterns  110 B excepting the plurality of first lower patterns  110 A. Further, the plurality of first lower patterns  110 A is larger in modulus than the second lower patterns  110 B. When the stretchable display device  100  is deformed such as bending or stretching, the plurality of first lower patterns  110 A disposed under the plurality of individual substrates  111  may support the plurality of individual substrates  111  as rigid lower patterns. Accordingly, various elements disposed on the plurality of individual substrates  111  may be supported together with the plurality of individual substrates  111  by the plurality of first lower patterns  110 A and damage to the elements due to deformation of the stretchable display device  100  may be reduced. 
     Further, when the stretchable display device  100  is deformed such as bending or stretching, the plurality of first lower patterns  110 A is made of the same material as the plurality of individual substrates  111  and has a modulus higher than the second lower patterns  110 B. Accordingly, the plurality of first lower patterns  110 A is stretched more than the plurality of individual substrates  111  without deformation, and the plurality of first lower patterns  110 A and the plurality of individual substrates  111  may keep firmly bonded to each other. Therefore, since the plurality of first lower patterns  110 A and the plurality of individual substrates  111  overlap each other in the stretchable display device  100  according to an embodiment of the present disclosure, the areas where the pixels are disposed may be more rigid. Accordingly, defect of the stretchable display device  100  may be reduced even if the stretchable display device  100  is continuously deformed such as bending or stretching. 
     Since the second lower patterns  110 B not overlapped with the plurality of individual substrates  111  are more flexible than the plurality of first lower patterns  110 A, the areas where the second lower patterns  110 B are disposed between the plurality of individual substrates  111  may be freely bent or stretched. Accordingly, the connecting lines  180  overlapped with the second lower patterns  110 B also may be freely bent or stretched. Therefore, the stretchable display device  100  according to an embodiment of the present disclosure may be more easily deformed such as bending or stretching. The present disclosure is not limited thereto. The modulus of the individual substrates may be higher than that of at least one part of the lower substrate as required. For example, in the case of only a predetermined area of the stretchable display device is stretched or the stretchable display device is only stretched in a predetermined direction, the modulus of the individual substrates may be configured to be higher than that of a part of the lower substrate corresponding to the predetermined area or the predetermined direction. 
     Connecting Line Composed of Base Polymer &amp; Conductive Particle 
     The connecting lines  180  are disposed between the plurality of individual substrates  111  and the lower substrate  110 . In more detail, the connecting lines  180  may be disposed with the top surfaces in contact with portions of some lower areas of the plurality of individual substrates  111  and the bottom surface of the upper adhesive layer  118  bonding the lower substrate  110  and the upper substrate  120 . However, when the upper substrate  120  is formed by coating, unlike that shown in  FIG. 3 , the upper substrate  120  may be disposed without using a separate adhesive layer. Accordingly, the connecting lines  180  may be disposed with the top surfaces in contact with some lower areas of the plurality of individual substrates  111  and the bottom surface of the upper substrate  120 . Further, the connecting lines  180  may be disposed with the bottom surfaces extending from some areas of the first lower patterns  110 A of the lower substrate  110  to the areas of the second lower patterns  110 B. The some areas of the first lower patterns  110 A may be areas corresponding to the contact holes CT formed at the individual substrates  111 . 
     The connecting lines  180  may be electrically connected with the pads  171  and  173  disposed on the individual substrates  111  through the contact holes CT formed at insulating layers under the pads, which should be electrically connected with the connecting lines  180  of the components constituting the individual substrates  111  and the light emitting element, that is, the gate pads  171  and the data pad  173 , and the individual substrates  111 . 
     The connecting lines  180  include first connecting lines  181  extending in an X-axial direction and second connecting lines  182  extending in a Y-axial direction. The first connecting line  181  is electrically connected with the gate pads  171  disposed on the individual substrates  111  through first contact hole CT 1 . The second connecting line  182  is electrically connected with the data pads  173  disposed on the individual substrates  111  through second contact holes CT 2 . 
     In common display devices, various lines such as a plurality of gate lines and a plurality of data lines are extended and disposed between a plurality of subpixels, and a plurality of subpixels is connected to one signal line. Accordingly, in common display devices, various lines such a gate line, a data line, a high-potential power line, and a reference voltage line extend from a side to the other side of the display devices on a substrate without disconnection. 
     Unlikely, in the stretchable display device  100  according to an embodiment of the present disclosure, various lines such as gate lines, data lines, high-potential power lines, and reference voltage lines, which are made of metal, are disposed on the plurality of individual substrates  111 . That is, in the stretchable display device  100  according to an embodiment of the present disclosure, various lines made of metal may be disposed only on the plurality of individual substrates  111  not in contact with the lower substrate  110 . Accordingly, various lines may be patterned to correspond to the plurality of individual substrates  111  and discontinuously disposed. 
     In the stretchable display device  100  according to an embodiment of the present disclosure, the pads  171  and  173  on two adjacent individual substrates  111  may be connected by a connecting line  180  to connect the discontinuous lines. That is, a connecting line  180  electrically connects the pads  171  and  173  on two adjacent individual substrates  111 . Accordingly, the stretchable display device  100  according to an embodiment of the present disclosure includes a plurality of connecting lines  180  to electrically connect various lines such as gate lines, data lines, high-potential power lines, and reference voltage lines between the plurality of individual substrates  111 . For example, gate lines may be disposed on a plurality of individual substrates  111  disposed adjacent to each other in the X-axial direction, and the gate pad  171  may be disposed at both ends of the gate lines. The plurality of gate pads  171  on the plurality of individual substrates  111  disposed adjacent to each other in the X-axial direction may be connected to each other by a connecting line  180  functioning as a gate line. Accordingly, the gate line disposed on the plurality of individual substrates  111  and the connecting line  180  disposed on the lower substrate  110  may function as one gate line. All various lines that may be included in the stretchable display device  100 , such as the data lines, high-potential power lines, and reference voltage lines, also each may function as one line by a connection line  180 , as described above. 
     Referring to  FIG. 2 , a first connecting line  181  may connect the pads on two parallel individual substrates  111  of the pads of a plurality of individual substrates  111  disposed adjacent to each other in the X-axial direction. The first connecting line  181  may function as a gate line or a low-potential power line, but is not limited thereto. For example, the first connecting line  181  may function as a gate line and may electrically connect the gate pads  171  on two individual substrates  111  disposed in parallel in the X-axial direction through the first contact holes CT 1  formed at the gate insulating layer  113 , the buffer layer  112 , and the individual substrates  111  disposed under the gate pads  171 . Accordingly, as described above, the gate pads  171  on a plurality of individual substrates  111  disposed in the X-axial direction may be connected by first connecting lines  181  that function as gate lines, and one gate signal may be transmitted. 
     Referring to  FIG. 2 , a second connecting line  182  may connect the pads on two parallel individual substrates  111  of the pads of a plurality of individual substrates  111  disposed adjacent to each other in the Y-axial direction. The second connecting line  182  may function as a data line, a high-potential power line, or a reference voltage line, but is not limited thereto. For example, the second connecting line  182  may function as a data line and may electrically connect the data pads  173  on two individual substrates  111  disposed in parallel in the Y-axial direction through the second contact holes CT 2  formed at the inter-layer insulating layer  114 , the gate insulating layer  113 , the buffer layer  112 , and the individual substrates  111 . Accordingly, as described above, the data pads  173  on a plurality of individual substrates  111  disposed in the Y-axial direction may be connected by the plurality of second connecting lines  182  that function as data lines, and one data signal may be transmitted. 
     In common stretchable display devices, connecting lines extend downward from above by forming contact holes at a planarization layer and a bank on a gate pad and a data pad. However, in this case, the connecting lines extend up a lower substrate from above light emitting elements, that is, the bank, so a step of the connecting lines is increased. Accordingly, the connecting lines formed to extend downward from above by forming contact holes at a planarization layer and a bank on a gate pad and a data pad are easily damaged by the large step being present. 
     However, according to the stretchable display device  100  according to an embodiment of the present disclosure, the connecting lines  180  are disposed to extend from some area of the first lower pattern  110 A of the lower substrate  110  to the area where the second lower pattern  110 B is disposed. Further, contact holes CT are formed at the insulating layer  113 , the buffer layer  112 , and the individual substrate  111  under the gate pad  171  formed on the individual substrate  111 , or contact holes are formed at the inter-layer insulating layer  114 , the gate insulating layer  113 , the buffer layer  112 , and the individual substrate  111  under the data pad  173 , and then the contact holes are filled with the same material as the connecting lines  180 . Thereafter, the connecting lines  180  and the gate pad  171  or the data pad  173  are electrically connected. Accordingly, the step of the connecting lines  180  is reduced, whereby damage to the connecting lines  180  may be reduced. 
     Referring to  FIG. 2 , the connecting line  180  includes a base polymer and conductive particles. In detail, the first connecting line  181  includes a base polymer and conductive particles and the second line  182  includes a base polymer and conductive particles. The first connecting line  181  may extend to the top surface of the lower substrate  110  in contact with the lower portion of the individual substrate  111  and the lower portion of the adhesive layer  118 . 
     The base polymer of the first connecting line  181  may be made of a bendable or stretchable insulating material similar to the lower substrate  110 . The base polymer, for example, may include silicon rubber such as Polydimethylsiloxane (PDMS), an elastomer such as polyurethane (PU), Styrene Butadiene Styrene (SBS), etc., but is not limited thereto. Accordingly, when the stretchable display device  100  is bent or stretched, the base polymer may not be damaged. The base polymer may be formed by coating a material for the base polymer or applying the material using a slit to the top surface of the lower substrate  110  and the bottom surface of the individual substrate  111 . 
     The conductive particles of the first connecting line  181  may be distributed by the base polymer. In detail, the first connecting line  181  may include conductive particles distributed with predetermined density in the base polymer. The first connecting line  181 , for example, may be formed by uniformly stirring conductive particles in a base polymer and then coating and hardening the base polymer with the conductive particles distributed therein to the top surface of the lower substrate  110 , and the bottom surface of the individual substrate  111 , and the bottom surface of the adhesive layer  118 , but is not limited thereto. The conductive particles may include at least one of silver (Ag), gold (Au), and carbon, but is not limited thereto. 
     The conductive particles distributed in the base polymer of the first connecting line  181  may form a conductive path electrically connecting the gate pads  171  disposed on adjacent individual substrates  111 . Further, the conductive particles distributed in the base polymer of the first connecting line  181  may form a conductive path electrically connecting a gate pad  171  on the outermost individual substrate  111  of a plurality of individual substrates  111  to a pad disposed in the non-active area NA. 
     Referring to  FIG. 2 , the base polymer and the conductive particles distributed in the base polymer of the first connecting line  181  may connect straight the gate pads  171  disposed on adjacent individual substrates  111 . To this end, base polymers may be formed in a straight shape connecting the plurality of individual substrates  111  in the manufacturing process. Accordingly, the conductive paths formed by the conductive particles distributed in the base polymers also may be straight. However, the shape and the process of forming the base polymer and the conductive particles of the first connecting line  181  may not be limited thereto. 
     Referring to  FIG. 2 , the second connecting line  182  may extend to the top surface of the second lower pattern  110 B of the lower substrate  110  in contact with the bottom surface of the individual substrate  111  and the bottom surface of the upper adhesive layer  118 . 
     The base polymer of the second connecting line  182  may be made of a bendable or stretchable insulating material similar to the lower substrate  110 , and may be made of the same material as the base polymer of the first connecting line  181 . The base polymer, for example, may include silicon rubber such as Polydimethylsiloxane (PDMS), an elastomer such as polyurethane (PU), Styrene Butadiene Styrene (SBS), etc., but is not limited thereto. 
     The conductive particles of the second connecting line  182  may be distributed by the base polymer. In detail, the second connecting line  182  may include conductive particles distributed with predetermined density in the base polymer. The conductive particles distributed at the upper portion and the lower portion in the base polymer of the second connecting line  182  may be substantially the same in density. The manufacturing process of the second connecting line  182  may be the same as that of the first connecting line  181  or may be simultaneously performed. 
     Referring to  FIG. 2 , the base polymer and the conductive particles distributed in the base polymer of the second connecting line  182  may connect straight the data pads  173  disposed on adjacent individual substrates  111 . To this end, base polymers may be formed in a straight shape connecting the plurality of individual substrates  111  in the manufacturing process. Accordingly, the conductive paths formed by the conductive particles distributed in the base polymers also may be straight. However, the shape and the process of forming the base polymer and the conductive particles of the second connecting line  182  may not be limited thereto. 
     In some embodiments, the base polymer of the connecting line  180  may be formed as a single layer between adjacent individual substrates  111  on the lower substrate  110 . In detail, a base polymer, unlike  FIG. 2 , may be disposed as a single layer between individual substrates  111 , which are most adjacent to each other in the X-axial direction, in contact with the lower substrate  110 . A base polymer may be formed to overlap all of a plurality of pads disposed in parallel at a side on one individual substrate  111 . Conductive particles may be separately formed to form a plurality of conductive paths on a base polymer, which is disposed as one layer, and respectively correspond to a plurality of pads. Accordingly, conductive paths formed by conductive particles may connect straight the pads disposed on adjacent individual substrates  111 . For example, conductive particles may be injected to form four conductive paths on a base polymer disposed as one layer between a plurality of individual substrates  111 . 
     In some embodiments, the base polymers of the connecting lines  180  may be disposed in the entire area of the lower substrate  110 . That is, the base polymers may be disposed in a single layer on the lower substrate  110 . Conductive particles may form a conductive path connecting the pads on a plurality of adjacent individual substrates  111  in the base polymer. 
     When the base polymers are disposed in a single layer in the entire area on the lower substrate  110 , there may be no separate process for patterning the base polymers. Accordingly, the process of manufacturing the base polymers and the connecting lines may be simplified, and the manufacturing costs and time may be reduced. 
     Since the base polymers are disposed in a single layer in the entire area on the lower substrate  110 , the base polymers may more efficiently distribute the force that is applied when the stretchable display device  100  is bent or stretched. 
     Referring to  FIG. 3 , the upper substrate  120 , the polarizing layer  190 , and the adhesive layer  118  are disposed on the encapsulation layer  117  and the lower substrate  110 . 
     The upper substrate  120  is a substrate supporting various components disposed under the upper substrate  120 . The upper substrate  120 , which is a flexible substrate, may be made of a bendable or stretchable insulating material. The upper substrate  120 , which is a flexible substrate, may reversibly expand and contract. The upper substrate may have an elastic modulus of several to hundreds of MPa and a tensile fracture rate of 100% or more. The thickness of the upper substrate  120  may be 10 μm to 1 mm, but is not limited thereto. 
     The upper substrate  120  may be made of the same material as the lower substrate  110 , for example, silicon rubber such as polyimethylsiloxane (PDMS) or an elastomer such as polyurethane (PU), so it may have flexibility. The material of the upper substrate  120 , however, is not limited thereto. 
     Referring to  FIG. 3 , although the upper substrate  120  is composed of a single pattern, it may include a first upper pattern and a second upper pattern that are different in moduli, similar to the lower substrate  110 . For example, if the upper substrate  120  has the first upper pattern and the second upper pattern, the first upper pattern may be disposed to correspond to the first lower pattern  110 A of the lower substrate  110  and the second upper pattern may be disposed to correspond to the second lower pattern  110 B of the lower substrate  110 . Further, the first upper pattern may be made of a rigid material having a higher modulus than the second upper pattern, and the second upper pattern may be made of a flexible material having a lower modulus than the first upper pattern. The second upper pattern may be disposed to surround the first upper pattern. 
     The upper substrate  120  and the lower substrate  110  may be bonded through the upper adhesive layer  118  disposed under the upper substrate  120  by applying pressure to the upper substrate  120  and the lower substrate  110 . However, the present disclosure is not limited thereto, and the upper adhesive layer  118  may not be provided, depending on embodiments. For example, the stretchable display device  100  may be manufactured by coating and then hardening the material for the upper substrate  120  without the upper adhesive layer  118 . 
     The polarizing layer  190  is disposed on the upper substrate  120 . The polarizing layer  190  may polarize light incident into the stretchable display device  100  from the outside. The polarized Light incident into the stretchable display device  100  through the polarizing layer  190  may be reflected in the stretchable display device  100 , so the phase of the light may be changed. The light with the changed phase may not pass through the polarizing layer  190 . Accordingly, the light incident in the stretchable display device  100  from the outside of the stretchable display device  100  is not discharged back to the outside of the stretchable display device  100 , so the external light reflection of the stretchable display device  100  may be reduced. 
     Individual Stretching Characteristic by Plurality Of Individual Substrates 
     A stretchable display device needs an easily bending or stretching characteristic, so there have been attempts to use substrates that are flexible due to a small modulus. However, when a flexible material such as Polydimethylsiloxane (PDMS) having a small modulus is used as a lower substrate that is disposed in the process of manufacturing a light emitting element, the substrate is damaged by high temperature, for example, temperature over 100° C. that is generated in the process of forming transistors and light emitting elements due to the characteristic that a material having a small modulus is weak to heat. 
     Accordingly, light emitting elements should be formed on a substrate made of a material that may withstand high temperature, so damage to the substrate may be reduced in the process of manufacturing the light emitting elements. Accordingly, there have been attempts to manufacture a substrate using materials that may withstand high temperature, which is generated in the manufacturing process, such as Polyimide (PI). However, materials that may withstand high temperature are not flexible due to large moduli, so substrates are not easily bent or stretched when stretching stretchable display devices. 
     Therefore, since the plurality of individual substrates  111  that are rigid substrates is disposed only in the areas where transistors  150  or organic light emitting elements  160  are disposed in the stretchable display device  100  according to an embodiment of the present disclosure, damage to the lower substrate  110  due to high temperature in the process of manufacturing the transistors  150  or the organic light emitting elements  160  may be reduced. 
     Further, the lower substrate  110  and the upper substrate  120  that are flexible substrates are respectively disposed under and over the plurality of individual substrates  111  in the stretchable display device  100  according to an embodiment of the present disclosure. Accordingly, the other areas of the lower substrate  110  and the upper substrate  120  excepting the areas overlapped with the plurality of individual substrates  111  may be easily stretched or bent, so the stretchable display device  100  may be achieved. Further, it is possible to reduce damage to the transistors  150 , the organic light emitting elements  160 , etc., disposed on the plurality of individual substrates  111  that are rigid substrates when the stretchable display device  100  is bent or stretched. 
     Effect of Connecting Line 
     When a stretchable display device is bent or stretched, a lower substrate that is a flexible substrate is deformed and individual substrates that are rigid substrates on which organic light emitting elements are disposed may not be deformed. In this case, if the lines connecting the pads disposed on the plurality of individual substrates are not made of an easily bendable or stretchable material, the lines may be damaged, such as cracking, due to deformation of the lower substrate. 
     However, in the stretchable display device  100  according to an embodiment of the present disclosure, it is possible to electrically connect the pads disposed on the plurality of individual substrates  111 , using the connecting lines  180  including a base polymer and conductive particles. The base polymer is flexible to be able to easily deform. Accordingly, according to the stretchable display device  100  of an embodiment of the present disclosure, even though the stretchable display device  100  is deformed such as bending or stretching, the areas between the plurality of individual substrates  111  are easily deformed by the connecting lines  180  including the base polymer. 
     Further, according to the stretchable display device  100  of an embodiment of the present disclosure, since the connecting lines  180  include conductive particles, the conductive paths composed of the conductive particles may not be damaged such as cracking even by deformation of the base polymer. For example, when the stretchable display device  100  is deformed such as bending or stretching, the lower substrate  110  that is a flexible substrate may be deformed in the other areas excepting the areas where the plurality of individual substrates  111  that are rigid substrates are disposed. The distance between the plurality of conductive particles disposed on the deforming lower substrate  110  may be changed. The density of the plurality of conductive particles disposed at the upper portion of the base polymers and forming the conductive paths may be maintained at a high level to be able to transmit electrical signals even though the distance between the plurality of conductive particles is increased. Accordingly, even if the base polymers are bent or stretched, the conductive paths formed by the plurality of conductive particles may smoothly transmit electrical signals. Further, even though the stretchable display device  100  is deformed such as bending or stretching, electrical signals may be transmitted between the pads. 
     In the stretchable display device  100  according to an embodiment of the present disclosure, since the connecting lines  180  include a base polymer and conductive particles, the connecting lines  180  connecting the pads disposed on the plurality of individual substrates  111  adjacent to each other may be disposed straight to have a minimum length. That is, the stretchable display device  100  may be achieved even if the connecting lines  180  are not curved. The conductive particles of the connecting lines  180  are distributed in the base polymers and form conductive paths. When the stretchable display device  100  is deformed such as bending or stretching, the conductive paths formed by the conductive particles may be bent or stretched. In this case, only the distance between the conductive particles is changed and the conductive paths formed by the conductive particles may still transmit electrical signals. Therefore, in the stretchable display device  100  according to an embodiment of the present disclosure, it is possible to minimize the space occupied by the connecting lines  180 . 
     Meanwhile, connecting lines are disposed on various components on a plurality of individual substrates spaced apart from each other on a lower substrate, for example, on the top surface of a bank. Further, the connecting lines may be connected with pads through contact holes formed at the bank and an insulating layer disposed under the bank. In this case, the connecting lines extend toward the lower substrate from the edge of an individual substrate and extend to an adjacent individual substrate, so the connecting lines may have a large step between the top surface of the bank and the top surface of the lower substrate. For example, since the individual substrates may have a large thickness of about 6 μm, the connecting lines may have a large step at the edges of the individual substrates. In this case, the base polymer itself may be cut by a step of the base polymer of the connecting lines, so the electrical path between the pads disposed on adjacent individual substrates may be cut and a percentage defective of the stretchable display device may increase. 
     Therefore, in the stretchable display device  100  according to an embodiment of the present disclosure, contact holes CT are formed at the insulating layers  112 ,  113 , and  114  and the individual substrate  111  disposed under the gate pad  171  and the data pad  173 . Thereafter, the connecting line  180  disposed on the bottom surface of the individual substrate  111  is electrically connected with the gate pad  171  and the data pad  173  through the contact holes CT. Accordingly, the connecting line  180  may not have a step. Therefore, damage to the connecting line  180  due to a step of the connecting line  180  is reduced, so reliability of the stretchable display device  100  may be improved. 
     Although the pads that are connected by the connecting line  180  are the gate pad  171  and the data pad  173  in the description referring to  FIGS. 1 to 3 , the present disclosure is not limited thereto. 
     Hereafter,  FIGS. 4A to 4G  are also referred to for describing a method of manufacturing the stretchable display device  100  according to an embodiment of the present disclosure. 
     Method of Manufacturing Stretchable Display Device According to Embodiment 
       FIG. 4A to 4G  are process cross-sectional views illustrating a method of manufacturing a stretchable display device according to an embodiment of the present disclosure. 
     First, referring to  FIG. 4A , an individual substrate  111  is disposed on a temporary substrate TS, and a plurality of insulating layers including a buffer layer  112 , a gate insulating layer  113 , an inter-layer insulating layer  114 , a planarization layer  115 , a bank  116 , and an encapsulation layer  117  that are sequentially formed, and a subpixel including a transistor  150  and an organic light emitting element  160  are formed on the individual substrate  111 . 
     Thereafter, as shown in  FIG. 4B , an upper adhesive layer  118  is disposed on the bottom surface of an upper substrate  120  to bond the temporary substrate TS and the upper substrate  120 . Thereafter, the upper substrate  120  and a polarizing layer  190  are bonded to the temporary substrate TS using the upper adhesive layer  118 . However, the present disclosure is not limited thereto. That is, it may be possible to coat a material for the upper substrate  120  onto the temporary substrate TS without the separate upper adhesive layer  118 , form the upper substrate  120  by hardening the material, and then dispose the polarizing layer  190  on the upper substrate  120 . 
     A protective film PF for protecting the upper substrate  120  and the polarizing layer  190  may be disposed on the upper substrate  120  and the polarizing layer  190  in the process of manufacturing the stretchable display device  100 . The protective film PF may be a film made of plastic, but protective glass made of glass, etc., may be used. 
     Thereafter, as shown in  FIG. 4C , the temporary substrate TS disposed under the individual substrate  111  and the upper adhesive layer  118  is removed, and then the components including the organic light emitting element  160 , the transistor  150 , the individual substrate  111 , the upper substrate  120 , the polarizing layer  190 , and the protective film PF are turned over. However, the present disclosure is not limited thereto and a process of turning over the components and then removing the temporary substrate TS may be performed. 
     Thereafter, as shown in  FIG. 4D , a first contact hole CT 1  is formed through the individual substrate  111 , the buffer layer  112 , and the gate insulating layer  113  to correspond to the area where the gate pad  171  is formed in order that the gate pad  171  is exposed. Further, a second contact hole CT 2  is formed through the individual substrate  111 , the buffer layer  112 , the gate insulating layer  113 , and the inter-layer insulating layer  114  to correspond to the area where the data pad  173  is formed in order that the data pad  173  is exposed. The contact holes CT may be formed by a dry etching process or a laser process. Accordingly, the cross-sectional area of the contact hole CT may decrease toward the pads  171  and  173  from a connecting line  180 . 
     Thereafter, as shown in  FIG. 4E , a first connecting line  181  is formed under the first contact hole CT 1 , the individual substrate  111  having the first contact hole CT 1 , and the upper adhesive layer  118 . Further, a second connecting line  182  is formed under the second contact hole CT 2 , the individual substrate  111  having the second contact hole CT 2 , and the upper adhesive layer  118 . Accordingly, the first connecting line  181  may extend on the bottom surfaces of the individual substrate  111  and the upper adhesive layer  118  in contact with the gate pad  171  through the first contact hole CT 1 . Further, the second connecting line  182  may extend on the bottom surfaces of the individual substrate  111  and the upper adhesive layer  118  in contact with the data pad  173  through the second contact hole CT 2 . 
     The first connecting line  181  and the second connecting line  182  may be simultaneously formed. That is, the first connecting line  181  and the second connecting line  182  may be simultaneously formed, with the contact hole CT formed, by coating a base polymer with conductive particles distributed therein to the bottom surfaces of the individual substrate  111  and the upper adhesive layer  118  and then hardening the base polymer. 
     Thereafter, as shown in  FIG. 4F , a lower substrate  110  may be bonded to the bottom surfaces of the individual substrate  111  and the connecting line  180 , using a lower adhesive layer  119 . However, the present disclosure is not limited thereto, and the lower adhesive layer  119  may not be provided. 
     Thereafter, as shown in  FIG. 4G , the protective film PF formed on the polarizing layer  190  is removed and then the components are turned back over, thereby achieving the stretchable display device  100  according to an embodiment of the present disclosure. 
     In the method of manufacturing the stretchable display device  100  according to an embodiment of the present disclosure, it is possible to easily contact the connecting line  180  and the pads  171  and  173  with each other by forming the contact hole CT through the individual substrate  111  and the insulating layers. Accordingly, it is possible to reduce the possibility of damage to the connecting line  180  through a very easy process. 
     Cross-Sectional Structure According to Another Embodiment 
       FIG. 5  is a schematic cross-sectional view showing one subpixel of a stretchable display device according to another embodiment of the present disclosure. A stretchable display device  500  shown in  FIG. 5  is substantially the same as the stretchable display device  100  shown in  FIGS. 1 to 3  except for including different connecting line  580 , gate pad  571 , and data pad  573  and further including a conductive contact pad  510 , so repeated description is not provided. 
     Referring to  FIG. 5 , a conductive contact pad  510  is disposed on the lower substrate  110  in the stretchable display device  500  according to another embodiment of the present disclosure. The conductive contact pad  510  is covered with the individual substrate  111 . Further, the conductive contact pad  510  may be disposed in an area corresponding to a gate pad  571  and a data pad  573  disposed on the individual substrate  111 . Since the individual substrate  111  is disposed to cover the conductive contact pad  510 , the bottom surfaces of the conductive contact pad  510  and the individual substrate  111  may be disposed in the same plane. The conductive contact pad  510  may be made of a conductive material. 
     The conductive contact pad  510  includes a first conductive contact pad  511  electrically connected with the gate pad  571  and a second conductive contact pad  512  electrically connected with the data pad  573 . 
     The first conductive contact pad  511  may be electrically connected with the gate pad  571  through a first contact hole CT 1  and the second conductive contact pad  512  may be electrically connected with the data pad  573  through the second contact hole CT 2 . The first conductive contact pad  511  may function as a portion of a gate line by being connected with a first connecting line  581  and the second conductive contact pad  512  may function as a portion of a data line by being connected with a second connecting line  582 . 
     The individual substrate  111  is disposed on the conductive contact pad  510 , and a buffer layer  112  and a gate insulating layer  113  are sequentially disposed on the individual substrate  111 . An active layer  152  of a transistor  150  is disposed on the buffer layer  112 , the gate pad  571  is disposed on the gate insulating layer  113  to correspond to the first conductive contact pad  511 , and a gate electrode  151  is disposed to overlap the active layer  152  of the transistor  150 . The gate pad  571  is in contact with the first conductive contact pad  511  through the first contact hole CT 1  formed through the individual substrate  111 , the buffer layer  112 , and the gate insulating layer  113 . A gate pad-forming material may be disposed in the first contact hole CT 1  when the gate pad  571  is formed. 
     An inter-layer insulating layer  114  is disposed on the gate insulating layer  113  having the gate pad  171  and the gate electrode  151 , and the data pad  573  is disposed on the inter-layer insulating layer  114  to correspond to the second conductive contact pad  512 . The data pad  573  may be made of the same material as a source electrode  153  and a drain electrode  154  of the transistor  150 , and the source electrode  153  may extend. The data pad  573  is electrically connected with the second conductive contact pad  512  through the second contact hole CT 2  formed through the individual substrate  111 , the buffer layer  112 , the gate insulating layer  113 , and the inter-layer insulating layer  114 . A data pad-forming material may be disposed in the second contact hole CT 2  when the data pad  573  is formed. 
     The connecting line  580  may be disposed under the individual substrate  111  to be in contact with the conductive contact pad  510 . In detail, as shown in  FIG. 5 , the first connecting line  581  may have a flat surface under the individual substrate  111  in contact with the first conductive contact pad  511  connected with the gate pad  571 . The second connecting line  582  may have a flat surface under the individual substrate  111  in contact with the second conductive contact pad  512  connected with the data pad  573 . 
     In the stretchable display device  500  according to another embodiment of the present disclosure, the individual substrate  111  is disposed to cover the conductive contact pad  510  and then the connecting line  580  is disposed on the bottom surface of the individual substrate  111 . Accordingly, the connecting line  580  is electrically connected with the gate pad  571  and the data pad  573  through the conductive contact pad  510 . Therefore, the connecting line  580  may have a flat surface. That is, the connecting line  580  has a uniform height from the lower substrate for its entire length. As a result, there is no step in the connecting line  580 , so the connecting line  580  may be stably formed and reliability of the display device  500  may be improved. 
     Hereafter,  FIGS. 6A to 6G  are also referred to for describing a method of manufacturing a stretchable display device  500  according to another embodiment of the present disclosure. 
     Method of Manufacturing Stretchable Display Device According to Another Embodiment 
       FIG. 6A to 6G  are process cross-sectional views illustrating a method of manufacturing a stretchable display device according to another embodiment of the present disclosure. 
     First, referring to  FIG. 6A , a first conductive contact pad  511  and a second conductive contact pad  512  are formed on a temporary substrate TS. The first conductive contact pad  511  and the second conductive contact pad  512  are formed with a predetermined distance therebetween. 
     An individual substrate  111  and a buffer layer  112  are sequentially formed on the temporary substrate TS having the first conductive contact pad  511  and the second conductive contact pad  512 , and then an active layer  152  of a transistor  150  is formed. A gate insulating layer  113  is formed on the buffer layer  112  having he active layer  152  and then a first contact hole CT 1  is formed through the individual substrate  111 , the buffer layer  112 , and the gate insulating layer  113  to expose the first conductive contact pad  511 . The first contact hole CT 1  may be formed by a dry etching process or a laser process. Accordingly, the cross-sectional area of the first contact hole CT 1  may increase as it goes away from the first conductive contact pad  511 . 
     Thereafter, as shown in  FIG. 6B , a gate pad  571  that is connected with the first conductive contact pad  511  through the first contact hole CT 1  is disposed and a gate electrode  151  is formed in an area overlapped with the active layer  152  of the transistor  150 . 
     An inter-layer insulating layer  114  is formed on the gate insulating layer  113  having the gate electrode  151  and the gate pad  571 . Thereafter, a second contact hole CT 2  is formed through the individual substrate  111 , the buffer layer  112 , the gate insulating layer  113 , and the inter-layer insulating layer  114  to expose the second conductive contact pad  512 . The second contact hole CT 2  may be formed by a dry etching process or a laser process. Accordingly, the cross-sectional area of the second contact hole CT 2  may increase as it goes away from the second conductive contact pad  512 . 
     Thereafter, as shown in  FIG. 6C , a data pad  573  that is connected with the second conductive contact pad  512  through the second contact hole CT 2  is disposed. Further, a source electrode  153  extending from the data pad  573  and a drain electrode  154  spaced apart from the source electrode  153  are formed, thereby achieving the transistor  150 . Thereafter, a planarization layer  115 , a bank  116 , an encapsulation layer  117 , and an organic light emitting element  160  are sequentially disposed. 
     Thereafter, as shown in  FIG. 6D , the individual substrate  111 , the buffer layer  112 , the gate insulating layer  113 , the inter-layer insulating layer  114 , the planarization layer  115 , and the bank layer  116  are cut into a plurality of individual substrates. Thereafter, an upper adhesive layer  118  is disposed on the bottom surface of an upper substrate  120  to bond the temporary substrate TS and the upper substrate  120 . Thereafter, the upper substrate  120  and a polarizing layer  190  are bonded to the temporary substrate TS using the upper adhesive layer  118 . 
     Thereafter, as shown in  FIG. 6E , the temporary substrate TS disposed under the individual substrate  111  and the upper adhesive layer  118  is removed, and then the components including the organic light emitting element  160 , the transistor  150 , the individual substrate  111 , the upper substrate  120 , the polarizing layer  190 , and the protective film PF are turned over. 
     Thereafter, a first connecting line  581  and a second connecting line  582  are formed to be electrically connected with the first conductive contact pad  511  and the second conductive contact pad  512  exposed by removing the temporary substrate TS. The first connecting line  581  and the second connecting line  582  extend from some area of the bottom surface of the individual substrate  111  corresponding to the first conductive contact pad  511  and the second conductive contact pad  512  to an area of the bottom surface of the upper adhesive layer  118 . In other words, the first connecting line  581  and the second connecting line  582  may extend from some area of the bottom surface of the individual substrate  111  respectively corresponding to the first conductive contact pad  511  and the second conductive contact pad  512  to the area of the upper adhesive layer  118 . The conductive contact pad  510  and the individual substrate  111  provide a flat bottom, so the connecting line  580  may be formed in a flat surface without a step. That is, the connecting line  580  has a uniform height from the lower substrate for its entire length. 
     Thereafter, as shown in  FIG. 6F , a lower substrate  110  may be bonded to the bottom surfaces of the individual substrate  111  and the connecting line  180 , using a lower adhesive layer  119 . However, the present disclosure is not limited thereto, and the lower adhesive layer  119  may not be provided. 
     Thereafter, as shown in  FIG. 6G , the protective film PF formed on the polarizing layer  190  is removed and then the components are turned back over, thereby achieving the stretchable display device  500  according to another embodiment of the present disclosure. 
     In the method of manufacturing the stretchable display device  500  according to another embodiment of the present disclosure, the conductive contact pad  510  is formed before the individual substrate  111  is disposed, and then the individual substrate  111  is disposed to cover the conductive contact pad  510 . Accordingly, it is possible to reduce the depth of the contact hole CT that is supposed to be formed later in the process of forming the contact hole CT, by the thickness of the conductive contact pad  510 . Therefore, the process of forming the contact hole CT may become easier. Further, in the method of manufacturing the stretchable display device  500  according to another embodiment of the present disclosure, since the individual substrate  111  is disposed to cover the conductive contact pad  510 , the individual substrate  111  and the conductive contact pad  510  provide a flat bottom. Accordingly, the connecting line  580  may have a flat surface without a step on the bottom surfaces of the individual substrate  111  and the conductive contact pad  510 . Therefore, in the stretchable display device  500  according to another embodiment of the present disclosure, it is possible to reduce deterioration of reliability of the stretchable display device  500  that may occur due to damage to the connecting line  580 . 
     Connecting Line Made of Conductive Component And Having Curved Shape 
       FIG. 7  is a partially enlarged plan view of the stretchable display device according to still another embodiment of the present disclosure.  FIG. 8  is a schematic cross-sectional view showing one subpixel of a stretchable display device according to still another embodiment of the present disclosure. A stretchable display device  700  shown in  FIGS. 7 and 8  is substantially the same as the stretchable display device  100  shown in  FIGS. 1 to 3  except for having different connecting lines  780 , so repeated description is not provided. Only encapsulation layers  117  and connecting lines  780  of various components disposed on individual substrates  111  are shown in  FIG. 7  for the convenience of description. 
     Referring to  FIG. 7 , the connecting lines  780  of a stretchable display device  700  according to still another embodiment of the present disclosure have a curved shape, for example, a curved shape means wave shape or a diamond shape. The connecting lines  780  electrically connect the pads disposed on adjacent individual substrates  111  of a plurality of individual substrates  111  and extend not in a straight line, but in a curved shape between the pads. For example, as shown in  FIG. 7 , the connecting lines  780  may have a sine waveform. However, the connecting lines  780  are not limited to this shape and may have various shapes. For example, the connecting lines  780  may extend in a zigzag shape or a plurality of diamond-shaped connecting lines extend with the apexes connected. 
     Referring to  FIG. 8 , a gate pad  171  is formed on the gate insulating layer  113 , a first connecting line  781  is formed in some area of the first lower pattern  110 A of the lower substrate  110  and on the second lower pattern  110 B. Further, the gate pads  171  and the first connecting line  781  may be electrically connected through a first contact hole CT 1  formed through the gate insulating layer  113 , the buffer layer  112 , and the individual substrate  111 . 
     Accordingly, referring to  FIG. 8 , the first connecting line  781  that may function as a gate line may electrically connect the gate pads  171  formed on adjacent individual substrates  111 . The first connecting line  781  is in contact with individual substrates  111  and the lower adhesive layer  118  between the plurality of individual substrates  111 . 
     The first connecting line  781  may be made of the same material as the gate electrode  151  and the gate pad  171 . However, the first connecting line  781  is not limited thereto and may be made of a conductive material different from the gate electrode  151  and the gate pad  171 . 
     Referring to  FIG. 8 , a data pad  173  is formed on the inter-layer insulating layer  114 . A source electrode  153  may extend outside an individual substrate  111 , may function as the data pad  173 , and may be electrically connected with the second connecting line  782 . However, the present disclosure is not limited thereto and the data pad  173  electrically connected with the source electrode  153  may be separately formed. 
     The second connecting line  782  is formed in some area of the first lower pattern  110 A of the lower substrate  110  and on the second lower pattern  110 B. The data pad  173  and the second connecting line  782  may be electrically connected through the second contact hole CT 2  formed through the inter-layer insulating layer  114 , the gate insulating layer  113 , the buffer layer  112 , and the individual substrate  111 . 
     The second connecting line  782  may be made of the same material as the first connecting line  781 . Accordingly, the second connecting line  782  and the first connecting line  781  may be simultaneously formed in the same process. That is, the second connecting line  782  may be made of the same material as the first connecting line  781 , the gate electrode  151 , and the gate pad  171 . The first connecting line  781  and the second connecting line  782  are made of the same material as the gate electrode  151  and the gate pad  171  in the stretchable display device  700  according to still another embodiment of the present disclosure. However, the present disclosure is not limited thereto, the first connecting line  781  and the second connecting line  782  may be made of the same material as or a different conductive material from the source electrode  153 , the drain electrode  154 , and the data pad  173 . 
     A step may be generated in the connecting lines disposed on a plurality of individual substrates and the connecting lines disposed on a lower substrate due to the thickness of various components disposed on the plurality of individual substrates. Accordingly, the connecting lines may be disconnected by a crack due to a step. 
     However, the connecting lines  780  are formed in a flat surface without a step in contact with a portion of the bottom surface of the individual substrate  111  and the bottom surface of the upper adhesive layer  118  in the stretchable display device  700  according to still another embodiment of the present disclosure. That is, the connecting lines  780  has a uniform height from the lower substrate for its entire length. Accordingly, it is possible to reduce damage to the connecting lines  780  and improve reliability of the stretchable display device  700 . 
     Stretchable Display Device Including Micro LED 
       FIG. 9  is a schematic cross-sectional view showing one subpixel of a stretchable display device according to still another embodiment of the present disclosure. A stretchable display device shown in  FIG. 9  is substantially the same as the stretchable display device  100  shown in  FIGS. 1 to 3  except for including an micro LED  960 , so repeated description is not provided. 
     Referring to  FIG. 9 , a common line CL is disposed on the gate insulating layer  113 . The common line CL is a line for applying a common voltage to a plurality of subpixels SPX. The common line CL may be made of the same material as the source electrode  153  and the drain electrode  154  of the transistor  150 , but is not limited thereto. 
     A reflective layer  983  is disposed on the inter-layer insulating layer  114 . The reflective layer  983  is a layer for discharging light emitted to the lower substrate  110  of light emitting from the LED  960  to the outside by reflecting the light upward through a stretchable display device  900 . The reflective layer  983  may be made of metal having high reflectance. 
     An adhesive layer  917  is disposed on the reflective layer  983  to cover the reflective layer  983 . The adhesive layer  917 , which is a layer for bonding the LED  960  on the reflective layer  983 , may insulate the reflective layer  983  made of metal and the LED  960 . The adhesive layer  917  may be made of a thermosetting material or a photocuring material, but is not limited thereto. Although the adhesive layer  917  covers only the reflective layer  983  in  FIG. 9 , the position of the adhesive layer  917  is not limited thereto. 
     The LED  960  is disposed on the adhesive layer  917 . The LED  960  overlaps the reflective layer  983 . The LED  960  includes an n-type layer  961 , an active layer  962 , a p-type layer  963 , an n-electrode  965 , and a p-electrode  964 . The LED  960  is described as a lateral LED  960  hereafter, but the structure of the LED  960  is not limited thereto. 
     In detail, the n-type layer  961  of the LED  960  overlaps the reflective layer  983  on the adhesive layer  917 . The n-type layer  961  may be formed by injecting an n-type impurity into a gallium nitride having excellent crystallinity. The active layer  962  is disposed on the n-type layer  961 . The active layer  962 , which is a light emitting layer that emits light in the LED  960 , may be made of a nitride semiconductor, for example, an indium gallium nitride. The p-type layer  963  is disposed on the active layer  962 . The p-type layer  963  may be formed by injecting a p-type impurity into a gallium nitride. However, the constituent materials of the n-type layer  961 , the active layer  962 , and the p-type layer  963  are not limited thereto. 
     The p-electrode  964  is disposed on the p-type layer  963  of the LED  960 . The n-electrode  965  is disposed on the n-type layer  961  of the LED  960 . The n-electrode  965  is spaced apart from the p-electrode  964 . In detail, the LED  960  may be manufactured by sequentially stacking the n-type layer  961 , the active layer  962 , and the p-type layer  963 , etching a predetermined portion of the active layer  962  and the p-type layer  963 , and then forming the n-electrode  965  and the p-electrode  964 . The predetermined portion is a space for spacing the n-electrode  965  and the p-electrode  964  and the predetermined portion may be etched to expose a portion of the n-type layer  961 . In other words, the surface of the LED  960  where the n-electrode  965  and the p-electrode  964  are disposed is not a planarized surface and may have different levels. Accordingly, the p-electrode  964  is disposed on the p-type layer  963 , the n-electrode  965  is disposed on the n-type layer  961 , and the p-electrode  964  and the n-electrode  965  are spaced from each other at different levels. Therefore, the n-electrode  965  may be disposed adjacent to the reflective layer  983  in comparison to the p-electrode  964 . The n-electrode  965  and p-electrode  964  may be made of a conductive material, for example, a transparent conductive oxide. Alternatively, the n-electrode  965  and p-electrode  964  may be made of the same material, but are not limited thereto. 
     A planarization layer  115  is disposed on the inter-layer insulating layer  114  and the adhesive layer  917 . The planarization layer  115  is a layer that planarizes the top surface of the transistor  150 . The planarization layer  115  may be disposed in an area excepting the area where the LED  960  is disposed while planarizing the top surface of the transistor  150 . The planarization layer  115  may be composed of two or more layers. 
     A first electrode  981  and a second electrode  982  are disposed on the planarization layer  115 . The first electrode  981  is an electrode that electrically connects the transistor  150  and the LED  960 . The first electrode  981  is connected with the p-electrode  964  of the LED  960  through a contact hole formed at the planarization layer  115 . The first electrode  981  is connected with the drain electrode  154  of the transistor  150  through contact holes formed at the planarization layer  115 . However, the first electrode  981  is not limited thereto and may be connected with the source electrode  153  of the transistor  150 , depending on the type of the transistor  150 . The p-electrode  964  of the LED  960  and the drain electrode  154  of the transistor  150  may be electrically connected by the first electrode  981 . 
     The second electrode  982  is an electrode that electrically connects the LED  960  and the common line CL. In detail, the second electrode  982  is connected with the common line CL through contact holes formed at the planarization layer  115  and the inter-layer insulating layer  114  and is connected with the n-electrode  965  of the LED  960  through a contact hole formed at the planarization layer  115 . Accordingly, the common line CL and the n-electrode  965  of the LED  960  are electrically connected. 
     When a stretchable display device  900  is turned on, voltages having different levels may be supplied respectively to the drain electrode  154  of the transistor  150  and the common line CL. The voltage that is applied to the drain electrode  154  of the transistor  150  may be applied to the first electrode  981  and a common voltage may be applied to the second electrode  982 . Voltages having different levels may be applied to the p-electrode  964  and the n-electrode  965  through the first electrode  981  and the second electrode  982 , so the LED  960  may emit light. 
     Although the transistor  150  is electrically connected with the p-electrode  964  and the common line CL is electrically connected with the n-electrode  965  in the description referring to  FIG. 9 , they are not limited thereto. That is, the transistor  150  may be electrically connected with the n-electrode  965  and the common line CL may be electrically connected with the p-electrode  964 . 
     A bank  116  is disposed on the planarization layer  115 , the first electrode  981 , and a second electrode  982 . The bank  116  is disposed to overlap an end of the reflective layer  983  and a portion not overlapped with the bank  116  of the reflective layer  983  may be defined as a light emitting area. The bank  116  may be made of an organic insulating material and may be made of the same material as the planarization layer  115 . The bank  116  may include a black material to reduce mixing of colors due to light emitted from the LED  960  and transmitted to an adjacent subpixel SPX. 
     The stretchable display device  900  according to still another embodiment of the present disclosure includes the LED  960 . Since the LED  960  is made of not an organic material, but an inorganic material, reliability is high, so the lifespan is longer than that of a liquid crystal display element or an organic light emitting element. The LED  960  is quickly turned on, consumes a small amount of power, has high stability because it has high shock-resistance, and may display high-luminance images because it has high emission efficiency. Accordingly, the LED  960  is an element that is suitable to be applied even to very large screens. In particular, since the LED  960  is made of not an organic material, but an inorganic material, an encapsulation layer that is required when an organic light emitting element is used may not be used. Accordingly, the encapsulation layer that may be easily damaged, such as cracking, when the stretchable display device  900  is stretched may not be provided. Accordingly, it is possible not to use an encapsulation layer that may be damaged when the stretchable display device  900  according to still another embodiment of the present disclosure is deformed such as bending and stretching, by using the LED  960  as a light emitting element in the stretchable display device  900 . Further, since the LED  960  is made of not an organic material, but an inorganic material, the light emitting elements of the stretchable display device  900  according to still another embodiment of the present disclosure may be protected from water or oxygen and their reliability may be high. 
     The exemplary embodiments of the present disclosure can also be described as follows: 
     According to an aspect of the present disclosure, there is provided a stretchable display panel, comprising: a lower substrate having an active area and a non-active area surrounding the active area; a plurality of individual substrates disposed on the lower substrate and located in the active area; a plurality of pixels disposed on the plurality of individual substrates; and a connection line disposed between the plurality of individual substrates and the lower substrate, wherein the modulus of the plurality of individual substrates is higher than that of at least one part of the lower substrate, and wherein the connecting line extends to the bottom surface of the individual substrates, such that the connecting line electrically connects a pad disposed on the individual substrates without a step in the top surface of the connecting line. 
     The lower substrate may include a plurality of first lower patterns overlapped with the plurality of individual substrates and a second lower pattern excepting the plurality of first lower patterns, the modulus of the first lower patterns being higher than that of the second lower pattern. 
     The second lower pattern may be disposed to surround the sides and the bottom surface of the plurality of first lower pattern. 
     The connection line electrically may connect with a pad disposed on the individual substrates through a contact hole at the bottom surface of the individual substrates. 
     The contact hole may be filled with the same material as the connecting line. 
     Cross-sectional areas of the contact holes may be decreased toward the pads from the connecting lines. 
     The stretchable display panel may further comprises a conductive contact pad disposed on the lower substrate, wherein the conductive contact pad is covered with the individual substrates, such that the bottom surfaces of the conductive contact pad and the individual substrates are disposed in the same plane, and wherein the connection line electrically connects with a pad disposed on the individual substrates through the conductive contact pad at the bottom surface of the individual substrates. 
     The pad may include a gate pad and a data pad. 
     The connecting line may include a base polymer and conductive particles distributed in the base polymer, the conductive particles forming a conductive path of a straight shape. 
     The base polymer may be formed as a single layer between adjacent individual substrates on the lower substrate, the conductive particles forming a plurality of conductive path in the single layer of base polymer. 
     The connecting lines may be made of the same material as at least one of conductive patterns constituting an emitting element and have a curved shape. 
     The connecting lines may have a flat surface. 
     The conductive particles may be distributed with a density gradient, such that conductivity by conductive particles is maximum at the upper portion of the base polymer. 
     According to another aspect of the present disclosure, there is provided a method of manufacturing a stretchable display device, the method comprising: disposing a plurality of individual substrates on a temporary substrate; forming a transistor and a emitting element on one surface of the plurality of individual substrates; disposing a protective film on the emitting element and removing the temporary substrate; forming a first connecting line and a second connecting line, which are respectively electrically connected with a gate pad and a data pad, on another surface of the plurality of individual substrates; and forming a lower substrate including a first lower pattern overlapped with the plurality of individual substrates and a second lower pattern surrounding the first lower pattern, wherein the forming a first connecting line and a second connecting line is forming a connecting line having a flat surface without a step. That is, in one embodiment, the connecting lines have a uniform height of their bottom most surface from the lower substrate for their entire length. 
     The first connecting line and the second connecting line may be made of the same material. 
     The first connecting line and the second connecting line include a base polymer and conductive particles distributed in the base polymer and have a straight shape. 
     The first connecting line and the second connecting line may be made of the same material as at least one of conductive patterns disposed on the plurality of individual substrates. 
     The method may further comprises forming a first contact hole and a second contact hole corresponding to the gate pad and the data pad respectively in the plurality of individual substrates and an insulating layer disposed under the gate pad and the data pad on the plurality of individual substrates. 
     The forming a lower substrate may include bonding the lower substrate to the bottom surface of the individual substrate using an adhesive layer. 
     The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments. 
     These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.