Patent Description:
As display devices which are used for a monitor of a computer, a television, or a cellular phone, there are an organic light emitting display device (OLED) which is a self-emitting device and a liquid crystal display device (LCD) which requires a separate light source.

An applicable range of the display device is diversified to personal digital assistants as well as monitors of computers and televisions and a display device with a large display area and a reduced volume and weight is being studied.

Recently, a stretchable display device which is manufactured by forming a display unit and a wiring line on a flexible substrate such as plastic which is a flexible material so as to be stretchable in a specific direction and changed in various forms is getting attention as a next generation display device.

<CIT> describes, in a machine translation, a stretchable display device and a preparation method thereof, wherein the stretchable display device includes: a flexible substrate, a plurality of pixel islands arranged on the flexible substrate, and electrical inter-island connecting line connecting two adjacent pixel islands, the orthographic projections of the inter-island connecting line in the first plane and the second plane are both curved, wherein the first plane is in line with the flexible plane parallel to the substrate, and the second plane is a plane that passes through the two pixel islands and is perpendicular to the flexible substrate. The stretchable display device provided by the embodiments of the present invention has the advantage of effectively enhancing the stretch resistance of the stretchable display device.

<CIT> describes a stretchable electric circuit and a manufacturing method thereof. The method for manufacturing the stretchable electric circuit includes forming a mold substrate, forming a stretchable substrate having a first flat surface and a first corrugated surface outside the first flat surface on the mold substrate, removing the mold substrate, forming a corrugated wire on the first corrugated surface, and forming an electric device connected to the corrugated wire on the first flat surface.

An object to be achieved by the present disclosure is to provide a stretchable display device which is capable of minimizing a line resistance.

Another object to be achieved by the present disclosure is to provide a stretchable display device which is capable of ensuring a sufficient extension rate.

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, a stretchable display device includes a plurality of first substrates which is disposed on a lower substrate to be spaced apart from each other and includes at least one pixel, where the lower substrate is a flexible substrate; a plurality of connection substrates which connects adjacent first substrates among the plurality of first substrates; a plurality of connection lines which electrically connects pads disposed on the plurality of adjacent first substrates and is disposed on side surfaces of the plurality of connection substrates, wherein each of the plurality of connection lines is disposed on at least two side surfaces of each respective connection substrate of the plurality of connection substrates, and adjacent to each other and spaced apart from each other by each respective connection substrate. Therefore, a resistance of the connection line may be minimized.

Other detailed matters of the exemplary embodiments are included in the detailed description and the drawings.

According to the present disclosure, a connection line is formed on a side surface of the connection substrate to sharply reduce a resistance of the connection line.

According to the present disclosure, a width of a connection line in a curved area is minimized to improve an extension rate.

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. 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.

Hereinafter, a stretchable display device according to exemplary embodiments of the present disclosure will be described in detail with reference to accompanying drawings.

A stretchable display device may be referred to as a display device which is capable of displaying images even though the display device is bent or extended. The stretchable display device may have a high flexibility as compared with a general display device of the related art. Therefore, a shape of a stretchable display device may be freely changed in accordance with manipulation of a user to bend or extend a stretchable display device. For example, when the user holds ends of the stretchable display device to pull the stretchable display device, the stretchable display device may be extended by the force of the user. Alternatively, when the user disposes the stretchable display device on a wall surface which is not flat, the stretchable display device may be disposed to be bent in accordance with the shape of the surface of the wall. Further, when a force applied by the user is removed, the stretchable display device may return to its original shape.

<FIG> is an exploded perspective view of a stretchable display device according to an exemplary embodiment of the present disclosure.

Referring to <FIG>, a stretchable display device <NUM> includes a lower substrate DS, a plurality of first substrates ST1, a plurality of second substrates ST2, a plurality of connection substrates CS, a chip on film (COF) <NUM>, a printed circuit board PCB, and an upper substrate US.

The lower substrate DS is a substrate which supports and protects several components of the stretchable display device <NUM>. The lower substrate DS which is a soft substrate or a flexible substrate may be configured by an insulating material which is bendable or extendable. For example, the lower substrate DS may be formed of a silicon rubber such as polydimethylsiloxane (PDMS) or an elastomer such as polyurethane (PU) or polytetrafluoroethylene (PTFE) and thus have a flexible property. However, the material of the lower substrate DS is not limited thereto.

The lower substrate DS is a flexible substrate so as to be reversibly expanded and contracted. Further, an elastic modulus of the lower substrate DS may be several MPa to several hundreds of MPa, for example, may be <NUM> MPa to <NUM> MPa. Further, an extension rupture rate of the lower substrate DS may be <NUM>% or higher. Here, the extension rupture rate refers to an extension rate at a timing when an object to be extended is broken or cracked. A thickness of the lower substrate DS may be <NUM> to <NUM> but is not limited thereto.

The lower substrate DS may have a display area AA and a non-display area NA enclosing the display area AA.

The display area AA is an area in which an image is displayed in the stretchable display device <NUM> and a display element and various driving elements for driving the display element are disposed in the display area AA. The display area AA may include a plurality of pixels including a plurality of sub-pixels. The plurality of pixels is disposed in the display area AA and includes a plurality of display elements. The plurality of sub-pixels may be connected to various wiring lines, respectively. For example, the plurality of sub-pixels may be connected to various wiring lines such as a gate line, a data line, an emission signal line, a high potential power line, a low potential power line, a reference voltage line, or a compensation signal line.

The non-display area NA is an area adjacent to the display area AA. The non-display area NA is adjacent to the display area AA to enclose the display area AA. In the non-display area NA, no image is displayed and wiring lines and circuit units may be formed. For example, in the non-display area NA, a plurality of pads is disposed, and the pads may be connected to the plurality of sub-pixels of the display areas AA, respectively.

The plurality of first substrates ST1 and the plurality of second substrates ST2 are disposed on the lower substrate DS. The plurality of first substrates ST1 may be disposed in the display area AA of the lower substrate DS and the plurality of second substrates ST2 may be disposed in the non-display area NA of the lower substrate DS. Even though in <FIG>, the plurality of second substrates ST2 is disposed at an upper (first) side and a left (second) side of the display area AA in the non-display area NA, it is not limited thereto and may be disposed in an arbitrary area of the non-display area NA.

The plurality of first substrates ST1 and the plurality of second substrates ST2 are rigid substrates and are spaced apart from each other to be independently disposed on the lower substrate DS. The plurality of first substrates ST1 and the plurality of second substrates ST2 may be more rigid than the lower substrate DS. That is, the lower substrate DS may be more flexible than the plurality of first substrates ST1 and the plurality of second substrates ST2, and the plurality of first substrates ST1 and the plurality of second substrates ST2 are more rigid than the lower substrate DS.

The plurality of first substrates ST1 and the plurality of second substrates ST2 which are rigid substrates may be formed of a plastic material having flexibility and for example, may be formed of polyimide (PI), polyacrylate, or polyacetate, but is not limited thereto. In this case, the plurality of first substrates ST1 and the plurality of second substrates ST2 may be formed of the same material but are not limited thereto and may be formed of different materials.

Moduli of the plurality of first substrates ST1 and the plurality of second substrates ST2 may be higher than that of the lower substrate DS. The modulus is an elastic modulus which represents a ratio being deformed by a stress with respect to a stress applied to the substrate. The higher the modulus, the higher a degree of hardness. Therefore, the plurality of first substrates ST1 and the plurality of second substrates ST2 may be a plurality of rigid substrates having rigidity as compared with the lower substrate DS. The moduli of the plurality of first substrates ST1 and the plurality of second substrates ST2 may be <NUM> times or higher than the modulus of the lower substrate DS but are not limited thereto. For example, elastic moduli of the plurality of first substrates ST1 and the plurality of second substrates ST2 may be <NUM> GPa to <NUM> GPa depending on a transparency. More specifically, when the plurality of first substrates ST1 and the plurality of second substrates ST2 are transparent, the elastic modulus is <NUM> GPa and when the plurality of first substrates ST1 and the plurality of second substrates ST2 are opaque, the elastic modulus is <NUM> GPa.

The COF <NUM> is a film on which various components are disposed on a base film <NUM> having a flexibility and supplies signals to the plurality of sub-pixels of the display area AA. The COF <NUM> may be bonded to the plurality of pads of the plurality of second substrates ST2 disposed in the non-display area NA and supplies a power voltage, a data voltage, a gate voltage, or the like to each of the plurality of sub-pixels of the display area AA through the pads. The COF <NUM> includes the base film <NUM> and a driving IC <NUM>. Further, various components may be additionally disposed thereon.

The base film <NUM> is a layer which supports the driving IC <NUM> of the COF <NUM>. The base film <NUM> may be formed of an insulating material, and for example, may be formed of an insulating material having a flexibility.

The driving IC <NUM> is a component which processes data for displaying images and a driving signal for processing the images. In <FIG>, even though it is illustrated that the driving IC <NUM> is mounted by the COF <NUM> technique, it is not limited thereto and the driving IC <NUM> may be mounted by chip on glass (COG), tape carrier package (TCP), or the like.

In <FIG>, one second substrate ST2 is disposed in the non-display area NA at the upper (first) side of the display area AA so as to correspond to one row of first substrates ST1 disposed in the display area AA and one COF <NUM> is disposed for one second substrate ST2 but is not limited thereto. That is, one second substrate ST2 and one COF <NUM> may be disposed so as to correspond to the first substrates ST1 in a plurality of rows.

A control unit such as an IC chip or a circuit unit may be mounted on the printed circuit board PCB. Further, on the printed circuit board PCB, a memory or a processor may also be mounted. The printed circuit board PCB is a component which transmits a signal for driving the display element from the control unit to the display element. Even though in <FIG>, it is described that one printed circuit board PCB is used, the number of printed circuit boards PCB is not limited thereto.

Hereinafter, the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure will be described in more detail with reference to <FIG> and <FIG>.

<FIG> is an enlarged plan view of a stretchable display device according to an exemplary embodiment of the present disclosure. <FIG> is a cross-sectional view taken along the line III-III' of <FIG>. For the convenience of description, the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure will be described with reference to <FIG> together.

Referring to <FIG> and <FIG>, the stretchable display device <NUM> includes a lower substrate DS, a plurality of first substrates ST1, a plurality of connection substrates CS, a plurality of connection lines <NUM>, a plurality of pads <NUM>, a transistor <NUM>, and an LED <NUM>.

Referring to <FIG> and <FIG>, the plurality of first substrates ST1 is disposed on the lower substrate DS in the display area AA. The plurality of first substrates ST1 is spaced apart from each other to be disposed on the lower substrate DS. For example, as illustrated in <FIG> and <FIG>, the plurality of first substrates ST1 may be disposed on the lower substrate DS in a matrix but is not limited thereto.

Referring to <FIG> and <FIG>, a plurality of sub-pixels SPX which configures the plurality of pixels PX is disposed on the plurality of first substrates ST1 and a gate driver GD may be mounted on a second substrate ST2 located at a left (second) side of the display area AA, among the plurality of second substrates ST2. The gate driver GD may be formed on the second substrate ST2 in a gate in panel (GIP) manner when various elements on the first substrate ST1 are manufactured. Therefore, various circuit configurations which configure the gate driver GD, such as various transistors, capacitors, and wiring lines may be disposed on the plurality of second substrates ST2. However, it is not limited thereto and the gate driver GD may be mounted in a chip on film (COF) manner. Further, the plurality of second substrates ST2 may be disposed in the non-display area NA located at a right (third) side of the display area AA and the gate driver GD may be mounted also on the plurality of second substrates ST2 located at the right (third) side of the display area AA. The second and third sides may be opposing sides. The first side may be perpendicular to the second and third sides.

Referring to <FIG>, a size of the plurality of second substrates ST2 may be larger than a size of the plurality of first substrates ST1. Specifically, a size of each of the plurality of second substrates ST2 may be larger than a size of each of the plurality of first substrates ST1. As described above, on each of the plurality of second substrates ST2, the gate driver GD is disposed. For example, one stage of the gate driver GD may be disposed on each of the plurality of second substrates ST2. Therefore, an area occupied by various circuit configurations which configure one stage of the gate driver GD may be relatively larger than an area of the first substrate ST1 on which the pixel PX is disposed. As a result, the size of each of the plurality of second substrates ST2 may be larger than the size of each of the plurality of first substrates ST1.

Referring to <FIG> and <FIG>, the plurality of connection substrates CS may be disposed between the plurality of first substrates ST1, between the plurality of second substrates ST2, or between the plurality of first substrates ST1 and the plurality of second substrates ST2. The plurality of connection substrates CS may be substrates which connect adjacent first substrates ST1, adjacent second substrates ST2, or the first substrate ST1 and the second substrate ST2 which are adjacent to each other. The plurality of connection substrates CS may be simultaneously and integrally formed with the same material as the plurality of first substrates ST1 and the plurality of second substrates ST2 but is not limited thereto.

Referring to <FIG>, the plurality of connection substrates CS has a wavy shape on a flat surface. For example, as illustrated in <FIG>, the plurality of connection substrates CS may have a sine wave shape. However, the shape of the plurality of connection substrates CS is not limited thereto and for example, the plurality of connection substrates CS may extend with a zigzag pattern or may be formed with various shapes such as a shape extended by connecting a plurality of rhombus-shaped substrates at vertexes. Further, the number and the shape of the plurality of connection substrates CS illustrated in <FIG> are illustrative and the number and the shape of the plurality of connection substrates CS may vary depending on the design.

Referring to <FIG>, a buffer layer <NUM> is disposed on the plurality of first substrates ST1. The buffer layer <NUM> is formed on the plurality of first substrates ST1 to protect various components of the stretchable display device <NUM> from permeation of moisture H<NUM>O and oxygen O<NUM> from the outside of the lower substrate DS and the plurality of first substrates ST1. The buffer layer <NUM> may be configured by an insulating material and for example, configured by a single layer or a plurality of layers of an inorganic layer formed of silicon nitride (SiNx), silicon oxide (SiOx), and silicon oxynitride (SiON). However, the buffer layer <NUM> may be omitted depending on a structure or a characteristic of the stretchable display device <NUM>.

The buffer layer <NUM> may be formed only in an area where the lower substrate DS overlaps the plurality of first substrates ST1 and the plurality of second substrates ST2. As described above, the buffer layer <NUM> may be formed of an inorganic material so that the buffer layer <NUM> may be easily cracked or damaged during a process of extending the stretchable display device <NUM>. In this case, the buffer layer <NUM> is not formed in an area between the plurality of first substrates ST1 and the plurality of second substrates ST2 but is patterned to have a shape of the plurality of first substrates ST1 and the plurality of second substrates ST2 to be disposed only above the plurality of first substrates ST1 and the plurality of second substrates ST2. In other words, the buffer layer <NUM> may not be formed on the plurality of connection substrates CS. Therefore, in the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure, the buffer layer <NUM> is formed only in an area overlapping the plurality of first substrates ST1 and the plurality of second substrates ST2 which are rigid substrates. Therefore, even though the stretchable display device <NUM> is bent or extended to be deformed, the damage of the buffer layer <NUM> may be suppressed.

Referring to <FIG>, the transistor <NUM> including a gate electrode <NUM>, an active layer <NUM>, a source electrode <NUM>, and a drain electrode <NUM> is formed on the buffer layer <NUM>.

First, referring to <FIG>, the active layer <NUM> is disposed on the buffer layer <NUM>. For example, the active layer <NUM> may be formed of an oxide semiconductor, amorphous silicon (a-Si), polycrystalline silicon (poly-Si), an organic semiconductor, or the like.

A gate insulating layer <NUM> is disposed on the active layer <NUM>. The gate insulating layer <NUM> is a layer for electrically insulating the gate electrode <NUM> from the active layer <NUM> and may be formed of an insulating material. For example, the gate insulating layer <NUM> may be formed as a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) which is an inorganic material or a multiple layer of silicon nitride (SiNx) or silicon oxide (SiOx) but it is not limited thereto.

The gate electrode <NUM> is disposed on the gate insulating layer <NUM>. The gate electrode <NUM> is disposed to overlap the active layer <NUM>. The gate electrode <NUM> may be any one of various metal materials, for example, any one of molybdenum (Mo), aluminum (Al), chrome (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu) or an alloy of two or more of them, or a multiple-layer thereof, but it is not limited thereto.

An interlayer insulating layer <NUM> is disposed on the gate electrode <NUM>. The interlayer insulating layer <NUM> is a layer which insulates the gate electrode <NUM> from the source electrode <NUM> and the drain electrode <NUM> and is formed of an inorganic material, similarly to the buffer layer <NUM>. For example, the interlayer insulating layer <NUM> may be configured by a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) which is an inorganic material or a multi-layer of silicon nitride (SiNx) or silicon oxide (SiOx), but it is not limited thereto.

The source electrode <NUM> and the drain electrode <NUM> which are in contact with the active layer <NUM>, respectively, are disposed on the interlayer insulating layer <NUM>. The source electrode <NUM> and the drain electrode <NUM> are disposed on the same layer to be spaced apart from each other. The source electrode <NUM> and the drain electrode <NUM> may be in contact with the active layer <NUM> to be electrically connected to the active layer <NUM>. The source electrode <NUM> and the drain electrode <NUM> may be any one of various metal materials such as molybdenum (Mo), aluminum (Al), chrome (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu) or an alloy of two or more of them, or a multi-layer thereof, but it is not limited thereto.

The gate insulating layer <NUM> and the interlayer insulating layer <NUM> are patterned to be formed only in an area overlapping the plurality of first substrates ST1. The gate insulating layer <NUM> and the interlayer insulating layer <NUM> are also formed of the inorganic material, similarly to the buffer layer <NUM>, so that the gate insulating layer <NUM> and the interlayer insulating layer <NUM> may also be easily cracked to be damaged during the process of extending the stretchable display device <NUM>. Therefore, the gate insulating layer <NUM> and the interlayer insulating layer <NUM> are not formed in an area between the plurality of first substrates ST1 but are patterned to have a shape of the plurality of first substrates ST1 to be formed only above the plurality of first substrates ST1.

In <FIG>, even though among various transistors which may be included in the stretchable display device <NUM>, only a driving transistor is illustrated for the convenience of description, a switching transistor or a capacitor may also be included in the display device. Further, in this specification, even though it is described that the transistor <NUM> has a coplanar structure, various transistors such as a staggered structure may also be used.

Referring to <FIG>, a plurality of pads <NUM> is disposed on the interlayer insulating layer <NUM>. In the drawing, even though it is illustrated that the plurality of pads <NUM> is disposed on the first substrates ST1, the plurality of pads <NUM> may also be disposed on the second substrates ST2. The plurality of pads <NUM> may be pads which transmit any one of various signals such as a gate signal, a data signal, an emission signal, a high potential power signal, a low potential power signal, a reference voltage signal, and a compensation signal to the plurality of sub-pixels SPX, but is not limited thereto. The plurality of pads <NUM> may be formed of the same material as the source electrode <NUM> and the drain electrode <NUM> but is not limited thereto.

The plurality of pads <NUM> includes a first pad <NUM> and a second pad <NUM>. The first pad <NUM> may be connected to a first connection line <NUM>. The second pad <NUM> may be connected to a second connection line <NUM>.

Referring to <FIG>, a planarization layer <NUM> is formed on the transistor <NUM> and the interlayer insulating layer <NUM>. The planarization layer <NUM> planarizes an upper portion of the transistor <NUM>. The planarization layer <NUM> may comprise a single layer or a plurality of layers and may be formed of an organic material. Therefore, the planarization layer <NUM> may also be referred to as an organic insulating layer. For example, the planarization layer <NUM> may be formed of an acrylic organic material but is not limited thereto.

Referring to <FIG>, the planarization layer <NUM> is disposed on the plurality of first substrates ST1 to cover top surfaces and side surfaces of the buffer layer <NUM>, the gate insulating layer <NUM>, and the interlayer insulating layer <NUM>. By doing this, the planarization layer <NUM> encloses the buffer layer <NUM>, the gate insulating layer <NUM>, and the interlayer insulating layer <NUM> together with the plurality of first substrates ST1. In some embodiments, the term "cover" may mean of "on. " Specifically, the planarization layer <NUM> may be disposed so as to cover a top surface and a side surface of the interlayer insulating layer <NUM>, a side surface of the gate insulating layer <NUM>, a side surface of the buffer layer <NUM>, and a part of a top surface of the plurality of first substrates ST1.

The planarization layer <NUM> may supplement a step on the side surfaces of the buffer layer <NUM>, the gate insulating layer <NUM>, and the interlayer insulating layer <NUM> and enhance an adhesive strength of the planarization layer <NUM> and the connection line <NUM> disposed on the side surface of the planarization layer <NUM>. For example, the side surface of the planarization layer <NUM> may have a slope which is gentler than a slope formed by a side surface of the interlayer insulating layer <NUM>, a side surface of the gate insulating layer <NUM>, and a side surface of the buffer layer <NUM>. Therefore, the connection line <NUM> which is disposed to be in contact with the side surface of the planarization layer <NUM> is disposed with a gentle slope so that when the stretchable display device <NUM> is extended, a stress generated in the connection line <NUM> is reduced. Further, the crack occurring in the connection line <NUM> or a separation from the side surface of the planarization layer <NUM> may be suppressed.

In some exemplary embodiments, a passivation layer may be formed between the transistor <NUM> and the planarization layer <NUM>. That is, the passivation layer may be formed to cover the transistor <NUM> to protect the transistor <NUM> from the permeation of the moisture and oxygen. The passivation layer may be formed of an inorganic material and configured by a single layer or a plurality of layers, but is not limited thereto.

Referring to <FIG>, a common line CL is disposed on the gate insulating layer <NUM>. The common line CL is a wiring line which applies a common voltage to the plurality of sub-pixels SPX. The common line CL may be formed of the same material as the gate electrode <NUM> of the transistor <NUM> but is not limited thereto.

Referring to <FIG>, a first connection pad <NUM> and a second connection pad <NUM> are disposed on the planarization layer <NUM>. The first connection pad <NUM> is an electrode which electrically connects an LED <NUM> to be described below and the transistor <NUM>. For example, the first connection pad <NUM> may electrically connect the drain electrode <NUM> of the transistor <NUM> and the LED <NUM> through a contact hole formed in the planarization layer <NUM>.

The second connection pad <NUM> is an electrode which electrically connects the LED <NUM> and the common line CL. For example, the second connection pad <NUM> may electrically connect the common line CL and the LED <NUM> through the contact hole formed in the planarization layer <NUM>.

Referring to <FIG>, the LED <NUM> is disposed on the first connection pad <NUM> and the second connection pad <NUM>. The LED <NUM> includes an n-type layer <NUM>, an active layer <NUM>, a p-type layer <NUM>, an n-electrode <NUM>, and a p-electrode <NUM>. The LED <NUM> of the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure has a flip-chip structure in which the n-electrode <NUM> and the p-electrode <NUM> are formed on one surface.

The n-type layer <NUM> may be formed by injecting an n-type impurity into gallium nitride (GaN). The n-type layer <NUM> may be disposed on a separate base substrate which is formed of a material which is capable of emitting light.

The active layer <NUM> is disposed on the n-type layer <NUM>. The active layer <NUM> is a light emitting layer which emits light in the LED <NUM> and may be formed of a nitride semiconductor, for example, indium gallium nitride (InGaN). The p-type layer <NUM> is disposed on the active layer <NUM>. The p-type layer <NUM> may be formed by injecting a p-type impurity into gallium nitride (GaN).

As described above, the LED <NUM> according to the exemplary embodiment of the present disclosure may be manufactured by sequentially laminating the n-type layer <NUM>, the active layer <NUM>, and the p-type layer <NUM>, and then etching a predetermined part to form the n-electrode <NUM> and the p-electrode <NUM>. In this case, the predetermined part which is a space for separating the n-electrode <NUM> and the p-electrode <NUM> from each other may be etched to expose a part of the n-type layer <NUM>. In other words, the surfaces of the LED <NUM> on which the n-electrode <NUM> and the p-electrode <NUM> are disposed are not flat surfaces but have different heights.

As described above, in the etched area, in other words, on the n-type layer <NUM> exposed by the etching process, the n-electrode <NUM> is disposed. The n-electrode <NUM> may be formed of a conductive material. In the meantime, in an area which is not etched, in other words, on the p-type layer <NUM>, the p-electrode <NUM> is disposed. The p-electrode <NUM> is also formed of a conductive material, and for example, may be formed of the same material as the n-electrode <NUM>. The p-electrode <NUM> and the n-electrode <NUM> described above may be defined as a first electrode and a second electrode of the LED <NUM>, respectively.

An adhesive layer AD is disposed on top surfaces of the first connection pad <NUM> and the second connection pad <NUM> and between the first connection pad <NUM> and the second connection pad <NUM> so that the LED <NUM> may be bonded onto the first connection pad <NUM> and the second connection pad <NUM>. In this case, the n-electrode <NUM> may be disposed on the second connection pad <NUM> and the p-electrode <NUM> may be disposed on the first connection pad <NUM>.

The adhesive layer AD may be a conductive adhesive layer in which conductive balls are dispersed in an insulating base member. Therefore, when heat or pressure is applied to the adhesive layer AD, the conductive balls are electrically connected in a portion applied with heat or pressure to have a conductive property and an area which is not pressurized may have an insulating property. For example, the n-electrode <NUM> is electrically connected to the second connection line <NUM> by means of the adhesive layer AD, and the p-electrode <NUM> is electrically connected to the first connection line <NUM> by means of the adhesive layer AD. That is, after applying the adhesive layer AD on the first connection pad <NUM> and the second connection pad <NUM> using an inkjet method, the LED <NUM> is transferred onto the adhesive layer AD and the LED <NUM> is pressurized and heated. By doing this, the first connection pad <NUM> is electrically connected to the p-electrode <NUM> and the second connection pad <NUM> is electrically connected to the n-electrode <NUM>. However, the remaining part of the adhesive layer AD excluding a part of the adhesive layer AD disposed between the n-electrode <NUM> and the second connection pad <NUM> and a part of the adhesive layer AD disposed between the p-electrode <NUM> and the first connection pad <NUM> has an insulating property.

In the meantime, the adhesive layer AD may be divided to be disposed on the first connection pad <NUM> and the second connection pad <NUM>, respectively. That is, the adhesive layer AD disposed between the p-electrode <NUM> and the first connection pad <NUM> may be defined as a first adhesive pattern and the adhesive layer AD disposed between the n-electrode <NUM> and the second connection pad <NUM> may be defined as a second adhesive pattern.

As described above, the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure has a structure in which the LED <NUM> is disposed on the lower substrate DS on which the transistor <NUM> is disposed. Therefore, when the stretchable display device <NUM> is turned on, different voltage levels which are applied to the first connection pad <NUM> and the second connection pad <NUM>, respectively, are transmitted to the n-electrode <NUM> and the p-electrode <NUM> so that the LED <NUM> emits light.

In the meantime, even though in <FIG>, it is illustrated that a bank is not used, the bank may be formed on the first connection pad <NUM>, the second connection pad <NUM>, the connection line <NUM>, and the planarization layer <NUM>. The bank may divide sub-pixels which are disposed on one side and the other side of the LED <NUM> to be adjacent to each other. The bank may be formed of an insulating material. Further, the bank may include a black material. The bank includes the black material to block wiring lines which may be visible through the display area AA. For example, the bank may be formed of a transparent carbon-based mixture and specifically, include carbon black. However, it is not limited thereto and the bank may be formed of a transparent insulating material.

Referring to <FIG> and <FIG>, the upper substrate US is disposed on the LED <NUM> and the lower substrate DS. The upper substrate US is a substrate which supports various components disposed below the upper substrate US. Specifically, the upper substrate US is formed by coating a material which configures the upper substrate US on the lower substrate DS and then curing the material to be disposed to be in contact with the lower substrate DS, the first substrate ST1, the second substrate ST2, and the connection substrate CS.

The upper substrate US which is a flexible substrate may be configured by an insulating material which is bendable or extendable. The upper substrate US is a flexible substrate so as to be reversibly expanded and contracted. Further, an elastic modulus of the upper substrate may be several MPa to several hundreds of MPa and an extension rupture ratio may be <NUM>% or higher. A thickness of the upper substrate US may be <NUM> to <NUM> but is not limited thereto.

The upper substrate US may be formed of the same material as the lower substrate DS. For example, the upper substrate US may be formed of a silicon rubber such as polydimethylsiloxane (PDMS) or an elastomer such as polyurethane (PU) or polytetrafluoroethylene (PTFE) and thus have a flexible property. However, the material of the upper substrate US is not limited thereto.

Even though not illustrated in <FIG>, a polarization layer may be disposed on the upper substrate US. The polarization layer may perform a function which polarizes light incident from the outside of the stretchable display device <NUM> to reduce the external light reflection. Further, an optical film other than the polarization layer may be disposed on the upper substrate US.

Referring to <FIG> and <FIG>, the plurality of connection lines <NUM> is disposed on the planarization layer <NUM> and the plurality of connection substrates CS. The plurality of connection lines <NUM> refers to wiring lines which electrically connect a plurality of pads <NUM> which are adjacent to each other. In this case, the connection line <NUM> and the pad <NUM> may be electrically connected to each other through a contact hole formed in the planarization layer <NUM>. The plurality of connection lines <NUM> may be configured by one of various wiring lines such as a gate line, a data line, an emission signal line, a high potential power line, a low potential power line, a reference voltage line, and a compensation signal line, but is not limited thereto.

The plurality of connection lines <NUM> is disposed between two adjacent first substrates ST1 to electrically connect two first substrates ST1. Specifically, the plurality of connection lines <NUM> is disposed on a top surface and a side surface of the connection substrate CS which connects two adjacent first substrates ST1 and two adjacent second substrates ST2. Further, the plurality of connection lines <NUM> may be disposed between two adjacent second substrates ST2 and between the first substrate ST1 and the second substrate ST2 which are adjacent to each other.

In an area corresponding to the connection substrate CS, the plurality of connection lines <NUM> is formed to have the same shape as the plurality of connection substrates CS to overlap each other. That is, the plurality of connection lines <NUM> may have the same wavy shape as the plurality of connection substrates CS above the plurality of connection substrates CS.

The plurality of connection lines <NUM> includes the first connection line <NUM> and the second connection line <NUM>. The first connection line <NUM> and the second connection line <NUM> may be disposed between the plurality of first substrates ST1, between the plurality of second substrates ST2, or between the plurality of first substrates ST1 and the plurality of second substrates ST2.

The first connection line <NUM> is formed to extend to the top surface and the side surface of the connection substrate CS while being in contact with a top surface and a side surface of the planarization layer <NUM> disposed on the first substrate ST1. Further, the second connection line <NUM> is formed to extend to the top surface and the side surface of the connection substrate CS while being in contact with the top surface and the side surface of the planarization layer <NUM> disposed on the first substrate ST1.

In <FIG> and <FIG>, the first connection line <NUM> refers to a wiring line extending in an X-axis (first) direction among the plurality of connection lines <NUM>, and the second connection line <NUM> refers to a wiring line extending in a Y-axis (second) direction among the plurality of connection lines <NUM>. The first and second directions are perpendicular to one another. The first connection line <NUM> and the second connection line <NUM> may be configured to transmit different signals to the plurality of sub-pixels SPX. That is, a signal transmitted by the first connection line <NUM> may be different from a signal transmitted by the second connection line <NUM>.

The plurality of connection lines <NUM> may be formed of a metal material such as copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo) or a stacked structure of metal materials such as copper/molybdenum-titanium (Cu/Moti) or titanium/aluminum/titanium (Ti/Al/Ti), but is not limited thereto.

The display device includes various signal lines such as a gate line, a data line, an emission signal line, a high potential power line, a low potential power line, a reference voltage line, or a compensation signal line. In the case of a general display device, various signal lines are disposed to extend as a straight line between the plurality of sub-pixels and the plurality of sub-pixels is connected to one signal line. Therefore, in the general display device, various signal lines may extend from one side of the display device to the other side without being disconnected from the substrate.

In contrast, in the case of the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure, a straight signal line which is considered to be used for the general display device is disposed only on the plurality of first substrates ST1 and the plurality of second substrates ST2. That is, in the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure, a straight signal line may be disposed only on the plurality of first substrates ST1 and the plurality of second substrates ST2.

In the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure, in order to connect discontinuous wiring lines on the first substrate ST1 or the second substrate ST2, the pads <NUM> on the adjacent substrates ST1 and ST2 may be connected by the connection lines <NUM>. That is, the connection line <NUM> electrically connects pads <NUM> on two adjacent first substrates ST1, on two adjacent second substrates ST2, and on the first substrate ST1 and the second substrate ST2. Therefore, in the stretchable display device <NUM> according to the exemplary embodiment of the present disclosure, straight signal lines on the plurality of first substrates ST1 and the plurality of second substrates ST2 may be electrically connected to each other by the plurality of connection lines <NUM>.

For example, the gate line may be disposed on the plurality of first substrates ST1 disposed to be adjacent to each other in the X-axis direction and the gate pad may be disposed on both ends of the gate line. For example, the first pad <NUM> may be one of the gate pads disposed on both ends of the gate line of the sub-pixel SPX. The first connection line <NUM> may serve as a gate line. The first pad <NUM> on the plurality of first substrates ST1 which are disposed to be adjacent to each other in the X-axis direction may be connected to each other by the first connection line <NUM> on the connection substrate CS. Therefore, the gate line disposed on the plurality of first substrates ST1 and the first connection line <NUM> disposed on the connection substrate CS may serve as one gate line. Accordingly, one gate signal may be transmitted to the gate electrode <NUM> of the plurality of sub-pixels SPX through the first pad <NUM>, the first connection line <NUM>, and the gate lines disposed on the plurality of first substrates ST1.

Further, the data line may be disposed on the plurality of first substrates ST1 disposed to be adjacent to each other in the Y-axis direction and a data pad may be disposed on both ends of the data line. For example, the second pad <NUM> may be one of the data pads disposed on both ends of the data line of the sub-pixel SPX. The second connection line <NUM> may serve as a data line. The second pad <NUM> on the plurality of first substrates ST1 which are adjacent to each other in the Y-axis direction may be connected to each other by the second connection line <NUM> on the connection substrate CS. Therefore, the data line disposed on the plurality of first substrates ST1 and the second connection line <NUM> disposed on the connection substrate CS may serve as one data line. Accordingly, one data signal may be transmitted to the plurality of sub-pixels SPX through the second pad <NUM>, the second connection line <NUM>, and the data lines disposed on the plurality of first substrates ST1.

Further, the connection line <NUM> may further include a wiring line which connects pads on the plurality of first substrates ST1 and the plurality of second substrates ST2 to each other or connects pads on two second substrates ST2 which are disposed to be parallel, among pads on the plurality of second substrates ST2 adjacent in the Y-axis direction.

<FIG> is a view illustrating a connection line of a stretchable display device according to an exemplary embodiment of the present disclosure. <FIG> is a cross-sectional view taken along the line V-V' of <FIG>.

Even though a shape of the connection line illustrated in <FIG> is partially different from a shape of the connection line illustrated in <FIG>, for the convenience of description, a shape of the connection line will be described with reference to the connection line illustrated in <FIG>. Further, the first connection line and the second connection line are disposed in different directions, but substantially have the same shape, so that the first connection line and the second connection line may be collectively described as a connection line.

Referring to <FIG>, a plurality of connection substrates CS and a plurality of connection lines <NUM> have wavy shapes, respectively. As described above, the plurality of connection substrates CS and the plurality of connection lines <NUM> may have various shapes such as a sine wave shape or a zigzag pattern.

Therefore, the plurality of connection substrates CS and the plurality of connection lines <NUM> may be disposed in a linear area SA and a non-linear area CA, respectively. In some embodiments, the linear area SA may be referred to as a straight area SA and the non-linear area CA may be referred to as a curved area CA. That is, areas where the plurality of connection substrates CS and the plurality of connection lines <NUM> are disposed may be divided into the straight area SA and the curved area CA. In the straight area SA, each of the plurality of connection substrates CS and the plurality of connection lines <NUM> may extend in a straight line without being bent or in a substantially straight line. Further, in the curved area CA, each of the plurality of connection substrates CS and the plurality of connection lines <NUM> may be bent with a selected curvature and not extended straightly. The selected curvature in the curved area CA may be selected or predetermined based on various factors such as the distance between adjacent first substrates ST1, the degree of stretchability, the degree of elasticity, or the like. However, in <FIG>, it is illustrated that each of the plurality of connection substrates CS and the plurality of connection lines <NUM> is bent in the curved area CA while maintaining a predetermined curvature. However, the present disclosure is not limited thereto, and depending on the necessity for a design, each of the plurality of connection substrates CS and the plurality of connection lines <NUM> may be bent in the curved area CA while maintaining a variable curvature or curved at a predetermined angle.

Referring to <FIG>, the plurality of connection lines <NUM> is disposed on both side surfaces, a first side surface <NUM> and a second side surface <NUM> of the plurality of connection substrates CS. Each of the plurality of connection lines <NUM> may be formed as a dual line which is in contact with both the first side surface <NUM> and the second side surface <NUM> of the connection substrate CS. That is, each of the plurality of connection lines <NUM> is not disposed on the top surface of the connection substrates CS, but may be disposed on both side surfaces of the connection substrates CS with a dual line shape. However, the present disclosure is not limited thereto, and depending on the necessity for a design, the plurality of connection lines <NUM> may be formed as a single line which is in contact with only one side surface of both side surfaces.

Further, the plurality of connection lines <NUM> may be in contact with the lower substrate DS but is not limited thereto, and depending on the necessity for a design, the plurality of connection lines <NUM> may be spaced apart from the lower substrate DS.

A thickness T1 of the plurality of connection lines <NUM> may be <NUM> to <NUM>.

As described above, in the stretchable display device according to the exemplary embodiment of the present disclosure, the plurality of connection lines <NUM> may be formed on both side surfaces of the connection substrate CS as a dual line. By doing this, the plurality of connection lines <NUM> is connected in parallel so that the line resistance may be sharply reduced. Accordingly, in order to drive the stretchable display device, a delay of a signal which is applied to the connection line <NUM> may be reduced or minimized. As a result, a display quality of the stretchable display device may be improved.

Further, in the stretchable display device of the related art, the plurality of connection lines is disposed only on a top surface of the connection substrate so that the plurality of connection lines is disposed in a horizontal direction with respect to the lower substrate. By doing this, when the stretchable display device of the related art was extended, an extension stress applied to the plurality of connection lines was measured to be up to <NUM> MPa. As a result, in the stretchable display device in the related art, the plurality of connection lines may be highly likely to be cracked, which causes disconnection.

In contrast, in the stretchable display device according to the exemplary embodiment of the present disclosure, the plurality of connection lines <NUM> is disposed on both side surfaces of the connection substrate CS to dispose the plurality of connection lines <NUM> in a direction perpendicular to the lower substrate DS. That is, the position of the plurality of connection lines <NUM> may be closer to a curvature center axis of a wavy shape of the plurality of connection lines <NUM>. By doing this, when the stretchable display device according to the exemplary embodiment of the present disclosure is extended, an extension stress applied to the plurality of connection lines <NUM> is measured to be up to <NUM> MPa. That is, the extension stress applied to the plurality of connection lines <NUM> is reduced by up to <NUM> times at the same extension rate. Therefore, the stretchable display device according to the exemplary embodiment of the present disclosure may solve the disconnection problem of the connection lines <NUM>, which results in improvement of the extension reliability of the stretchable display device.

<FIG> is a view illustrating a connection line of a stretchable display device according to another exemplary embodiment of the present disclosure. <FIG> is a cross-sectional view taken along the line VII-VII' of <FIG>.

Only difference between the stretchable display device according to the exemplary embodiment of the present disclosure and a stretchable display device according to another exemplary embodiment of the present disclosure is the arrangement of the connection line. Therefore, a redundant description will be omitted and the arrangement of the connection will be described in detail.

As illustrated in <FIG>, a connection line <NUM> of the stretchable display device according to another exemplary embodiment of the present disclosure has different shapes in a straight area SA and a curved area CA.

The connection line <NUM> includes a plurality of connection lines 620C disposed in the curved area CA and a plurality of connection lines <NUM> disposed in the straight area SA. That is, referring to <FIG>, a plurality of connection lines 620C disposed in the curved area CA is disposed only on both side surfaces of the connection substrate CS and a plurality of connection lines <NUM> disposed in the straight area SA is disposed only on a top surface of the connection substrate CS. That is, the plurality of connection lines 620C disposed in the curved area CA is disposed on both side surfaces of the connection substrate CS as a dual line and a plurality of connection lines <NUM> disposed in the straight area SA is disposed on the top surface of the connection substrate CS as a single line.

When the stretchable display device is extended, an extension stress which is applied to the curved area CA is relatively higher than that of the straight area SA. Therefore, the plurality of connection lines 620C disposed in the curved area CA is very highly likely to be cracked. Therefore, in the stretchable display device according to the exemplary embodiment of the present disclosure, the plurality of connection lines 620C is disposed only on both side surfaces of the connection substrate CS in the curved area CA. Therefore, the plurality of connection lines 620C may be disposed to be perpendicular to the lower substrate DS in the curved area CA. That is, the position of the plurality of connection lines 620C may be closer to a curvature center axis of a wavy shape of the plurality of connection lines 620C. Therefore, the stretchable display device of the present disclosure may withstand a high stress in the curved area CA so that the extension rate may be improved.

Further, a thickness T2 of the connection line <NUM> disposed in the straight area SA and a thickness T1 of the connection line 620C disposed in the curved area CA may be different from each other. That is, the thickness T1 of the connection line 620C disposed in the curved area CA may be smaller than the thickness T2 of the connection line <NUM> disposed in the straight area SA. Therefore, the thickness T1 of the connection line 620C disposed in the curved area CA is relatively small so that the stretchable display device of the present disclosure may withstand a relatively high stress in the curved area CA which is more vulnerable to the extension stress than the straight area SA. Therefore, the extension rate may be improved.

<FIG> is a view illustrating a connection line of a stretchable display device according to still another exemplary embodiment of the present disclosure. <FIG> is a cross-sectional view taken along IX-IX' of <FIG>.

Only difference between the stretchable display device according to the exemplary embodiment of the present disclosure and a stretchable display device according to still another exemplary embodiment of the present disclosure is a shape of the connection line. Therefore, a redundant description will be omitted and the shape of the connection will be described in detail.

Referring to <FIG> and <FIG>, a plurality of connection lines <NUM> may be disposed not only on both side surfaces of the plurality of connection substrates CS, but also above the plurality of connection substrates CS. That is, the plurality of connection lines <NUM> may be disposed to cover an external surface of the connection substrates CS, respectively. In other words, the plurality of connection lines <NUM> may be divided into an upper connection line 820U disposed on a top surface of the plurality of connection substrates CS and a lower connection line 820D disposed on both side surfaces of the plurality of connection substrates CS.

The plurality of connection lines <NUM> may be in contact with the lower substrate DS. However, it is not limited thereto and the plurality of connection lines <NUM> may be spaced apart from the lower substrate DS depending on the necessity of a design.

A thickness T3 of the lower connection line 820D disposed on both side surfaces of the plurality of connection substrates CS may be different from a thickness T4 of the upper connection line 820U disposed on the top surface of the plurality of connection substrates CS. That is, the thickness T3 of the lower connection line 820D may be smaller than the thickness T4 of the upper connection line 820U. For example, the thickness T3 of the lower connection line 820D may be <NUM> to <NUM> and the thickness T4 of the upper connection line 820U may be <NUM> to <NUM>.

As described above, in the stretchable display device according to still another exemplary embodiment of the present disclosure, the plurality of connection lines <NUM> may be formed to cover the external surface of the connection substrate CS. By doing this, a cross-sectional area of the plurality of connection lines <NUM> is increased so that the line resistance may be sharply reduced. Accordingly, in order to drive the stretchable display device, a delay of a signal which is applied to the connection line <NUM> may be reduced or minimized. As a result, a display quality of the stretchable display device may be improved.

<FIG> is a view illustrating a connection line of a stretchable display device according to still another exemplary embodiment of the present disclosure. <FIG> is a cross-sectional view of a display device taken along the line XI-XI' of <FIG>.

Only difference between the stretchable display device according to the exemplary embodiment of the present disclosure and a stretchable display device according to still another exemplary embodiment of the present disclosure is the arrangement of the connection line <NUM>. Therefore, a redundant description will be omitted and the arrangement of the connection will be described in detail.

The connection line <NUM> includes a plurality of connection lines <NUM> disposed in the straight area SA and a plurality of connection lines 1020C disposed in the curved area CA. That is, referring to <FIG>, a plurality of connection lines <NUM> disposed in the straight area SA is disposed on both side surfaces and a top surface of the connection substrate CS and a plurality of connection lines 1020C disposed in the curved area CA is disposed only on both side surfaces of the connection substrate CS. That is, the plurality of connection lines <NUM> disposed in the straight area SA may be disposed to cover the external surface of the connection substrate CS, but a plurality of connection lines 1020C disposed in the curved area CA may be disposed on both side surfaces of the connection substrate CS as a dual line.

In other words, the plurality of connection lines <NUM> disposed in the straight area SA may be divided into an upper connection line 1020U disposed on a top surface of the plurality of connection substrates CS and a lower connection line 1020D disposed on both side surfaces of the plurality of connection substrates CS.

When the stretchable display device is extended, an extension stress which is applied to the curved area CA is relatively higher than that of the straight area SA. Therefore, the plurality of connection lines 1020C disposed in the curved area CA is very highly likely to be cracked. Therefore, in the stretchable display device according to the exemplary embodiment of the present disclosure, the plurality of connection lines <NUM> is disposed only on both side surfaces of the connection substrate CS in the curved area CA. Therefore, the plurality of connection lines 1020C may be disposed to be perpendicular to the lower substrate DS in the curved area CA. That is, the position of the plurality of connection lines 1020C may be closer to a curvature center axis of a wavy shape of the plurality of connection lines 1020C. Therefore, the stretchable display device of the present disclosure may withstand high stress in the curved area CA so that the extension rate may be improved.

Since a stretchable display device according to still another exemplary embodiment of the present disclosure has a technical feature in connection substrates CS1 and CS2, the connection substrates CS1 and CS2 will be described in detail.

As illustrated in <FIG> and <FIG>, the connection substrates CS1 and CS2 of the stretchable display device according to still another exemplary embodiment of the present disclosure have different thicknesses in a straight area SA and a curved area CA.

That is, referring to <FIG>, a plurality of first connection substrates CS1 disposed in the straight area SA may be formed to be thicker than a plurality of second connection substrates CS2 disposed in the curved area CA. That is, a thickness T5 of each of the plurality of first connection substrates CS1 disposed in the straight area SA may be larger than a thickness T6 of each of the plurality of second connection substrates CS2 disposed in the curved area CA.

However, a connection line <NUM> disposed on the plurality of first connection substrates CS1 disposed in the straight area SA and a connection line <NUM> disposed on the plurality of second supports CS2 disposed in the curved area CA may be formed to have the same thickness.

Therefore, components disposed in the straight area SA may be relatively thicker than components disposed in the curved area CA.

In the case of the stretchable display device of the related art, a thickness of the straight area SA and a thickness of the curved area CA are uniform so that stress is concentrated on the curved area CA illustrated in <FIG>, but is not easily modified. Accordingly, since a vertical modification in the curved area CA of the stretchable display device of the related art is limited, an extension direction of the stretchable display device of the related art is limited.

In contrast, as illustrated in <FIG>, in the stretchable display device according to still another exemplary embodiment of the present disclosure, the thickness of the curved area CA is relatively thin, so that the stress may be satisfactorily distributed in the curved area CA. Accordingly, in the stretchable display device according to still another exemplary embodiment of the present disclosure, the curved area CA may be easily modified in a vertical direction.

As a result, in the stretchable display device according to still another exemplary embodiment of the present disclosure, stress is distributed in all directions so that there is no limitation in an extension direction and an extension reliability is also improved.

Only difference between the stretchable display device according to the exemplary embodiment of the present disclosure and a stretchable display device according to still another exemplary embodiment of the present disclosure is a shape of the connection line. Therefore, a redundant description will be omitted and the shape of the connection line will be described in detail.

As illustrated in <FIG>, a connection line <NUM> of the stretchable display device according to still another exemplary embodiment of the present disclosure has different shapes in a straight area SA and a curved area CA.

That is, referring to <FIG>, a plurality of connection lines <NUM> disposed in a straight area SA may include straight wiring lines and a plurality of connection lines disposed in the curved area CA may include curved wiring lines and reinforced patterns PT. In other words, the plurality of connection lines <NUM> disposed in the straight area SA may have a straight line shape with a predetermined line width and the plurality of connection lines 1520C disposed in the curved area CA may have a curved shape with a predetermined line width. Further, the reinforced patterns PT may be disposed in a part of the plurality of connection lines 1520C disposed in the curved area CA.

The above-described reinforced pattern PT may have a circular shape and a diameter of the reinforced pattern PT may be larger than a line width of the plurality of connection lines <NUM> disposed in the straight area SA. However, the shape of the reinforced pattern PT is not limited to a circular shape, but may be a polygon having a width or a diameter larger than the line width of the plurality of connection lines <NUM>.

In addition, similarly to the connection line <NUM>, the reinforced pattern PT may be formed of a metal material such as copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo) or a stacked structure of metal materials such as copper/molybdenum-titanium (Cu/Moti) or titanium/aluminum/titanium (Ti/Al/Ti), but is not limited thereto.

As illustrated in <FIG>, when the stretchable display device of the related art is extended, a higher extension stress is concentrated on the curved area CA. (An area represented with light gray in <FIG> and <FIG> refers to an area where a stress is concentrated and an area represented with dark gray refers to an area where a stress is less concentrated). Therefore, the plurality of connection lines disposed in the curved area CA is very highly likely to be cracked.

Accordingly, in the stretchable display device according to still another exemplary embodiment of the present disclosure, the connection line <NUM> including the reinforced pattern PT is disposed in the curved area CA so that the probability of cracks in the plurality of connection lines <NUM> may be lowered.

Specifically, as illustrated in <FIG>, the reinforced pattern PT in the curved area CA is less affected by the extension stress so that the curved area CA may more effectively withstand the stress. Accordingly, the extension rate of the stretchable display device according to still another exemplary embodiment of the present disclosure may be improved.

Further, in the stretchable display device according to still another exemplary embodiment of the present disclosure, the diameter of the reinforced pattern PT is larger than the line width of the connection line <NUM> so that the resistance of the connection line <NUM> is reduced, which may also reduce a signal transfer delay of the connection line <NUM>.

The exemplary embodiments of the present disclosure can also be described as follows:
According to an aspect of the present disclosure, a stretchable display device includes a plurality of first substrates which is disposed on a lower substrate to be spaced apart from each other and includes at least one pixel; a plurality of connection substrates which connects adjacent first substrates among the plurality of first substrates; and a plurality of connection lines which electrically connects pads disposed on the plurality of adjacent first substrates and is disposed on side surfaces of the plurality of connection substrates. Therefore, a resistance of the connection line may be reduced or minimized.

Each of the plurality of connection lines may be disposed on both side surfaces of each of the plurality of connection substrates to be connected in parallel.

The plurality of connection substrates and the plurality of connection lines may have a wavy shape and include a straight area in which the plurality of connection substrates and the plurality of connection lines extend in a straight line and a curved area in which the plurality of connection substrates and the plurality of connection lines are curved.

In the straight area and the curved area, the plurality of connection lines may be disposed only on the both side surfaces of the plurality of connection substrates.

A thickness of each of the plurality of connection lines may be <NUM> to <NUM>.

In the curved area, the plurality of connection lines may be disposed only on the both side surfaces of the plurality of connection substrates and in the straight area, the plurality of connection lines is disposed only on a top surface of the plurality of connection substrates.

A thickness of each of the connection lines disposed in the curved area may be smaller than a thickness of each of the connection lines disposed in the straight area.

In the straight area and the curved area, the plurality of connection lines may be disposed on a top surface and the side surfaces of the plurality of connection substrates.

Each of the plurality of connection lines may include an upper connection line disposed on the top surface of the plurality of connection substrates and a lower connection line disposed on the side surfaces of the plurality of connection substrates and a thickness of the lower connection line may be smaller than a thickness of the upper connection line.

In the curved area, the plurality of connection lines may be disposed on the side surfaces of the plurality of connection substrates and in the straight area, the plurality of connection lines is disposed on a top surface and the side surfaces of the plurality of connection substrates.

According to another aspect of the present disclosure, a stretchable display device comprises a plurality of first substrates which is disposed on a lower substrate to be spaced apart from each other and includes at least one pixel,
a plurality of connection substrates which connects a plurality of adjacent first substrates among the plurality of first substrates and a plurality of connection lines which electrically connects pads disposed on the plurality of adjacent first substrates.

A straight area in which the plurality of connection substrates and the plurality of connection lines extend in a straight line and a curved area in which the plurality of connection substrates and the plurality of connection lines are bent are defined.

A thickness of a plurality of first connection substrates disposed in the straight area may be larger than a thickness of a plurality of second connection substrates disposed in the curved area.

A thickness of the plurality of connection lines disposed in the straight area may be equal to a thickness of the plurality of connection lines disposed in the curved area.

The plurality of connection lines disposed in the curved area may include a reinforced pattern.

The reinforced pattern may have a circular shape and a diameter of the reinforced pattern is larger than a width of the plurality of connection lines disposed in the straight area.

Claim 1:
A stretchable display device (<NUM>), comprising:
a plurality of first substrates (ST1) disposed on a lower substrate (DS), wherein the first substrates are spaced apart from each other and each first substrate includes at least one pixel, and
wherein the lower substrate is a flexible substrate;
a plurality of connection substrates (CS) configured to connect adjacent first substrates among the plurality of first substrates;
a plurality of connection lines (<NUM>, <NUM>) configured to electrically connect pads (<NUM>) disposed on the plurality of adjacent first substrates, the plurality of connection lines being disposed on side surfaces (<NUM>, <NUM>) of the plurality of connection substrates; characterized in that
each of the plurality of connection lines (<NUM>, <NUM>) is disposed on at least two side surfaces (<NUM>, <NUM>) of each respective connection substrate of the plurality of connection substrates (CS), and adjacent to each other and spaced apart from each other by each respective connection substrate (CS)..