Display device and method of manufacturing a display device

Abstract

A display device and a method for manufacturing a display device. According to one aspect of this disclosure, the display device includes: a lower substrate and a plurality of pixel substrates disposed on the lower substrate. The display device further includes a plurality of transistors disposed on the plurality of pixel substrates and a planarization layer disposed on the plurality of pixel substrates to cover the upper portion of the plurality of transistors. The display device further includes common connection pads and a plurality of individual connection pads disposed on the planarization layer. The display device further includes a plurality of light-emitting diodes disposed on the common connection pads and the plurality of individual connection pads. At least one of the plurality of individual connection pads and the common connection pad may have a multilayer structure.

Description

Technical Field

[0001] This disclosure relates to a display device, and more specifically, to a stretchable display device with improved reliability of connection lines. Background Technology

[0002] Display devices used in computer monitors, televisions, mobile phones, etc., include self-emissive organic light-emitting display (OLED) devices and liquid crystal display (LCD) devices that require a separate light source.

[0003] As display devices are increasingly used in various fields such as computer monitors, televisions and personal mobile devices, display devices with large effective area and reduced size and weight have been studied.

[0004] Recently, stretchable display devices, in which display elements and circuits are formed on a flexible substrate made of flexible plastic, and which can be stretched in a specific direction and manufactured into various shapes, have attracted attention as the next generation of display devices. Summary of the Invention

[0005] One objective of this disclosure is to provide a display device that minimizes pad stripping during the process of repairing misaligned light-emitting diodes during transfer, while manufacturing.

[0006] Another objective of this disclosure is to provide a display device that, during manufacturing, suppresses misalignment of the light-emitting diodes caused by movement of the adhesive layer bonded to the light-emitting diodes during transfer.

[0007] Another objective of this disclosure is to provide a display device that can suppress the occurrence of dark spots caused by misalignment of light-emitting diodes and short circuits between power lines and common connection pads during manufacturing.

[0008] Another objective of this disclosure is to provide a display device that can suppress the occurrence of dark spots caused by misalignment of light-emitting diodes and short circuits between power lines and common connection pads during manufacturing.

[0009] Another objective of this disclosure is to provide a display device that, during manufacturing, suppresses the reduction in transfer efficiency and driving defects of the light-emitting diode caused by uneven placement of the adhesive layer bonding the light-emitting diode during transfer.

[0010] Another objective of this disclosure is to provide a method for manufacturing a display device, wherein an adhesive layer is selectively transferred to the entire upper surface of a planarization layer to simplify the manufacturing process.

[0011] The objectives of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the following description other objectives not mentioned above.

[0012] According to one aspect of this disclosure, a display device includes: a lower substrate and a plurality of pixel substrates disposed on the lower substrate. The display device further includes a plurality of transistors disposed on the plurality of pixel substrates and a planarization layer disposed on the plurality of pixel substrates to cover the upper portion of the plurality of transistors. The display device also includes a common connection pad and a plurality of individual connection pads disposed on the planarization layer. The display device further includes a plurality of light-emitting diodes disposed on the common connection pads and the plurality of individual connection pads. At least one of the plurality of individual connection pads and the common connection pad may have a multilayer structure.

[0013] According to another aspect of this disclosure, the display device includes: a plurality of pixel substrates disposed on a lower substrate, wherein a plurality of light-emitting diodes (LEDs) are disposed therein. The display device further includes a planarization layer covering an upper portion of the plurality of pixel substrates. The display device further includes a plurality of individual connection pads disposed on the planarization layer to correspond respectively to the plurality of LEDs. The display device further includes a common connection pad disposed on the planarization layer and electrically connected to all the plurality of LEDs. The display device further includes an adhesive layer electrically connecting the common connection pad and the plurality of individual connection pads to the plurality of LEDs. At least one of the plurality of individual connection pads and the common connection pad may have a lower pad and an upper pad disposed on the edge of the lower pad.

[0014] According to another aspect of this disclosure, the display device includes: a plurality of pixel substrates disposed on a lower substrate, and a plurality of light-emitting diodes (LEDs) disposed on the plurality of pixel substrates. The display device further includes a planarization layer covering the upper portion of the plurality of pixel substrates. The display device further includes a plurality of independent connection pads disposed on the planarization layer and corresponding to the plurality of LEDs respectively. The display device further includes a common connection pad disposed on the planarization layer and electrically connected to all the plurality of LEDs. The display device further includes an adhesive layer that electrically connects the plurality of independent connection pads and the common connection pad to the plurality of LEDs, and is configured to cover the entire upper surface of the planarization layer.

[0015] According to another aspect of this disclosure, a method for manufacturing a display device includes the following process: placing an adhesive layer comprising a base component and a plurality of conductive balls dispersed in the base component on a first transfer substrate. The method for manufacturing a display device further includes the following process: bringing the first transfer substrate close to the upper portion of a substrate having a planarization layer covering the upper portion of a plurality of transistors, and bonding the adhesive layer to the upper portion of the planarization layer. The method for manufacturing a display device further includes the following process: bringing a second transfer substrate having a plurality of light-emitting diodes disposed thereon close to the upper portion of the adhesive layer, and bonding the plurality of light-emitting diodes to the upper portion of the adhesive layer.

[0016] Further details of exemplary embodiments are included in the detailed description and accompanying drawings.

[0017] According to this disclosure, the occurrence of defects caused by pad damage can be minimized during the process of repairing misaligned areas of light-emitting diodes.

[0018] According to this disclosure, misalignment of the light-emitting diode that may occur when the adhesive layer connecting the light-emitting diode and the pad moves can be minimized.

[0019] According to this disclosure, the occurrence of dark spots caused by electrical connections made between the electrodes of the light-emitting diode and the power lines during the transfer of the light-emitting diode can be suppressed.

[0020] According to this disclosure, the electrodes used for electrically connecting the light-emitting diode and the plurality of conductive balls on the pads are separated from each other in a single layer. Therefore, the occurrence of short circuits or open circuits in the light-emitting diode can be suppressed.

[0021] According to this disclosure, the adhesive layer for electrically connecting the light-emitting diode to the pad is disposed on the entire upper surface of the planarization layer. Therefore, the reduction in the transfer efficiency of the light-emitting diode and driving defects caused by uneven placement of the adhesive layer can be reduced or minimized.

[0022] According to this disclosure, by bonding the adhesive layer to the entire upper surface of the planarization layer, the manufacturing process can be simplified. Furthermore, manufacturing time and costs can be reduced or minimized.

[0023] The effects of this disclosure are not limited to those illustrated above, and many more effects are included in this specification.

[0024] Appendix 1. A display device, the display device comprising:

[0025] Pixel substrate;

[0026] A plurality of transistors are disposed on the pixel substrate;

[0027] A planarization layer is disposed on the pixel substrate to cover the upper part of the plurality of transistors;

[0028] A common connection pad and a plurality of independent connection pads, wherein the common connection pad and the plurality of independent connection pads are disposed on the planarization layer; and

[0029] Multiple light-emitting diodes are disposed on the common connection pad and the multiple individual connection pads.

[0030] At least one of the plurality of independent connection pads and the common connection pad has a multi-layer structure.

[0031] Note 2. The display device according to Note 1, wherein the common connection pad includes a lower common connection pad disposed on the planarization layer and an upper common connection pad disposed on the lower common connection pad.

[0032] Note 3. The display device according to Note 2, wherein the upper common connection pad is made of a material that has a higher adhesion to the electrodes of the plurality of light-emitting diodes than to the lower common connection pad.

[0033] Appendix 4. The display device according to Appendix 3, wherein the lower common connection pad is made of copper (Cu), and

[0034] The upper common connection pad is made of gold (Au), titanium (Ti), aluminum (Al), or molybdenum (Mo).

[0035] Note 5. The display device according to Note 3, wherein the material of the upper common connection pad is different from the material of the lower common connection pad, and is the same as the material of the electrodes of the plurality of light-emitting diodes.

[0036] Note 6. The display device according to Note 2, wherein the upper common connection pad is disposed on the edge of the lower common connection pad.

[0037] Note 7. The display device according to Note 6, wherein the upper common connection pad is also disposed on the lower common connection pad corresponding to the space between the plurality of independent connection pads.

[0038] Note 8. The display device according to Note 7, wherein the upper common connection pad is arranged in a grid pattern on the lower common connection pad.

[0039] Note 9. The display device according to Note 6, wherein the upper common connection pad is arranged in a closed curve on the edge of the lower common connection pad.

[0040] Appendix 10. The display device according to Appendix 2, wherein the plurality of independent connection pads includes a lower independent connection pad disposed on the planarization layer and an upper independent connection pad disposed on the lower independent connection pad, and

[0041] The upper independent connection pad has a shape corresponding to the upper common connection pad.

[0042] Note 11. The display device according to Note 1 further includes:

[0043] Power lines, the power lines being disposed on the planarization layer; and

[0044] An insulating layer is disposed on the power line.

[0045] Note 12. The display device according to Note 11, wherein the insulating layer comprises a plurality of insulating patterns disposed on the power line.

[0046] Appendix 13. The display device according to Appendix 12, wherein each of the plurality of light-emitting diodes is bonded to a corresponding independent connection pad and a common connection pad of the plurality of independent connection pads via an adhesive layer, the adhesive layer being formed by dispersing conductive balls in a base component having adhesive and insulating properties, and

[0047] The distance between the plurality of insulating patterns is smaller than the size of the conductive ball.

[0048] Note 14. The display device according to Note 11, wherein, in the insulating layer, the portion relatively adjacent to the common connection pad has a smaller height than the portion relatively far from the common connection pad.

[0049] Note 15. The display device according to Note 11, wherein the insulating layer is configured to cover the side surface of the power line adjacent to the common connection pad.

[0050] Note 16. The display device according to Note 11, wherein the distance between the common connection pad and the plurality of independent connection pads is greater than the distance between the common connection pad and the power line.

[0051] Note 17. The display device according to Note 11, wherein the power line is configured to transmit high-potential power and is arranged to be adjacent to and insulated from the common connection pad.

[0052] Note 18. The display device according to Note 1, wherein each of the plurality of light-emitting diodes is disposed on a corresponding independent connection pad among the plurality of independent connection pads, and all of the plurality of light-emitting diodes are disposed on the common connection pad.

[0053] Note 19. The display device according to Note 1, wherein the independent connection pad is electrically connected to the first electrode of the light-emitting diode, and the common connection pad is connected to the second electrode of the light-emitting diode.

[0054] Appendix 20. A display device, the display device comprising:

[0055] A pixel substrate, wherein a plurality of light-emitting diodes are disposed in the pixel substrate;

[0056] A planarization layer covering the upper part of the pixel substrate;

[0057] Multiple independent connection pads are disposed on the planarization layer to correspond to the multiple light-emitting diodes respectively;

[0058] Common connection pads, which are disposed on the planarization layer and electrically connected to all of the plurality of light-emitting diodes; and

[0059] An adhesive layer electrically connects the common connection pad and the plurality of individual connection pads to the plurality of light-emitting diodes.

[0060] At least one of the plurality of independent connection pads and the common connection pad has a lower pad and an upper pad disposed on the lower pad.

[0061] Note 21. The display device according to Note 20, wherein the upper pad is made of a different material than the lower pad.

[0062] Note 22. The display device according to Note 20, wherein the upper pad is arranged in a grid pattern on the lower pad.

[0063] Note 23. The display device according to Note 20, wherein the upper pad is disposed on the edge of the lower pad.

[0064] Appendix 24. The display device according to Appendix 20 further includes:

[0065] High-potential power lines, wherein the high-potential power lines are disposed on the planarization layer; and

[0066] An insulating layer is disposed on the high-potential power line.

[0067] The common connection pad is disposed between the plurality of independent connection pads and the high-potential power line.

[0068] Note 25. The display device according to Note 24, wherein the insulating layer is configured to cover the side surface of the high-potential power line.

[0069] Appendix 26. A display device, the display device comprising:

[0070] Multiple pixel substrates are disposed on a lower substrate, and multiple light-emitting diodes are disposed on the multiple pixel substrates;

[0071] A planarization layer covering the upper part of the plurality of pixel substrates;

[0072] Multiple independent connection pads are disposed on the planarization layer and each corresponds to one of the multiple light-emitting diodes;

[0073] Common connection pads, which are disposed on the planarization layer and electrically connected to all of the plurality of light-emitting diodes; and

[0074] An adhesive layer electrically connects the plurality of individual connection pads and the common connection pad to the plurality of light-emitting diodes, and the adhesive layer is configured to cover the entire upper surface of the planarization layer.

[0075] Appendix 27. The display device according to Appendix 26, wherein the adhesive layer comprises a plurality of conductive balls and a base component, and

[0076] The plurality of conductive balls are disposed in a single layer while being dispersed in the base component.

[0077] Note 28. The display device according to Note 27, wherein the plurality of conductive balls are spaced apart from each other and are not electrically connected to each other, and the plurality of conductive balls electrically connect the plurality of individual connection pads and the common connection pad to the plurality of light-emitting diodes.

[0078] Appendix 29. The display device according to Appendix 27, wherein the plurality of conductive balls are spaced apart from each other parallel to the upper surface of the planarization layer, and the plurality of conductive balls are in contact with the electrodes of the plurality of light-emitting diodes, the plurality of individual connection pads and the common connection pad in a direction perpendicular to the upper surface of the planarization layer.

[0079] Note 30. The display device according to Note 27, wherein the thickness of the adhesive layer is equal to or less than the thickness of the planarization layer.

[0080] Appendix 31. A method for manufacturing a display device, the method comprising the following steps:

[0081] An adhesive layer comprising a base component and a plurality of conductive balls dispersed in the base component is placed on a first transfer substrate;

[0082] The first transfer substrate is brought close to the upper part of the lower substrate on which the planarization layer covering the upper part of a plurality of transistors is disposed, and the adhesive layer is bonded to the upper part of the planarization layer.

[0083] Separate the first transfer substrate from the adhesive layer bonded to the upper part of the planarization layer; and

[0084] The second transfer substrate, on which a plurality of light-emitting diodes are disposed, is brought close to the upper part of the adhesive layer, and the plurality of light-emitting diodes are bonded to the upper part of the adhesive layer.

[0085] Note 32. The method of manufacturing a display device according to Note 31, wherein the plurality of conductive balls are spaced apart from each other and are not electrically connected to each other, and the plurality of conductive balls electrically connect a plurality of independent connection pads and a common connection pad to the plurality of light-emitting diodes.

[0086] Note 33. The method of manufacturing a display device according to Note 32, wherein the plurality of conductive balls are disposed in a single layer. Attached Figure Description

[0087] The above and other aspects, features and other advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0088] Figure 1 This is an exploded perspective view of a display device according to an exemplary embodiment of the present disclosure;

[0089] Figure 2 This is an enlarged plan view of a display device according to an exemplary embodiment of the present disclosure;

[0090] Figure 3 It is along Figure 2 A cross-sectional view taken from line III-III';

[0091] Figure 4 This is a schematic enlarged plan view of a pixel substrate of a display device according to an exemplary embodiment of the present disclosure;

[0092] Figure 5A This is a schematic cross-sectional view of a pixel substrate of a display device according to another exemplary embodiment of the present disclosure;

[0093] Figure 5B This is an enlarged plan view of a pixel substrate of a display device according to another exemplary embodiment of the present disclosure;

[0094] Figure 6 This is an enlarged plan view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure;

[0095] Figure 7 This is an enlarged plan view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure;

[0096] Figure 8 This is a schematic cross-sectional view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure;

[0097] Figure 9 This is a schematic cross-sectional view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure;

[0098] Figure 10 This is a schematic cross-sectional view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure;

[0099] Figure 11 This is a schematic cross-sectional view showing a display device according to an exemplary embodiment of the present disclosure with the upper common connection pad removed by a repair process;

[0100] Figure 12A This is an enlarged plan view of a pixel substrate of a display device according to another embodiment of the present disclosure;

[0101] Figure 12B This is a schematic cross-sectional view of a pixel substrate of a display device according to another embodiment of the present disclosure; and

[0102] Figures 13A to 13D This is a schematic cross-sectional view illustrating a method of manufacturing a display device according to yet another embodiment of the present disclosure. Detailed Implementation

[0103] The advantages and features of this disclosure, as well as methods for achieving these advantages and features, will become clear from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings. However, this 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 to enable those skilled in the art to fully understand the disclosure and scope of this disclosure. Therefore, this disclosure will be limited only by the scope of the appended claims.

[0104] The shapes, dimensions, ratios, angles, quantities, etc., shown in the accompanying drawings used to describe exemplary embodiments of this disclosure are merely examples, and this disclosure is not limited thereto. Throughout the specification, the same reference numerals generally denote the same elements. Furthermore, in the following description of this disclosure, detailed explanations of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of this disclosure. Terms such as “comprising,” “having,” and “consisting of” as used herein are generally intended to allow for the addition of other components, unless these terms are used in conjunction with the term “only.” Unless otherwise expressly stated, any singular reference may include the plural.

[0105] Even if not explicitly stated, the components will be interpreted as including the normal error range.

[0106] When using terms such as “above,” “over,” “below,” and “beside” to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless these terms are used with the terms “exactly” or “directly.”

[0107] When one element or layer is disposed "on" another element or layer, the element or layer may be disposed directly on the other element or layer, or another element or layer may be inserted between them.

[0108] Although the terms "first," "second," etc., are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from others. Therefore, the first component mentioned below can be a second component in the technical concept of this disclosure.

[0109] Throughout the specification, the same reference numerals generally denote the same elements.

[0110] For ease of description, the dimensions and thickness of each component shown in the accompanying drawings are illustrated, and this disclosure is not limited to the dimensions and thickness of the components shown.

[0111] Features of the various embodiments of this disclosure can be attached or combined with each other in part or in whole, and can be technically interlocked and operated in various ways, and these embodiments can be performed independently or in association with each other.

[0112] In the following, a stretchable display device according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0113] <Stretchable display device>

[0114] Stretchable display devices can be described as display devices that can display images even when bent or stretched. Stretchable display devices can have greater flexibility than conventional typical display devices. Therefore, users can bend or stretch the stretchable display device, and the shape of the display device can freely change in response to user manipulation. For example, when a user grasps one end of the stretchable display device and pulls it, the stretchable display device can be stretched by the user's force. When a user places the stretchable display device on an uneven wall surface, the stretchable display device can bend along the shape of the wall. Furthermore, when the force applied by the user is removed, the display device can return to its original shape.

[0115] Figure 1 This is an exploded perspective view of a display device according to an exemplary embodiment of the present disclosure. (Refer to...) Figure 1 The display device 100 includes a lower substrate 110, a plurality of pixel substrates 111, a plurality of connecting members 120, a plurality of non-pixel substrates 121, a chip on film (COF) 130, a printed circuit board 140, and an upper substrate US.

[0116] The lower substrate 110 is a substrate used to support and protect various components of the display device 100. The lower substrate 110 is a ductile substrate and can be made of a flexible or stretchable insulating material. For example, the lower substrate 110 can be made of silicone rubber such as polydimethylsiloxane (PDMS) and elastomers such as polyurethane (PU) or polytetrafluoroethylene (PTFE). Therefore, the lower substrate 110 can have flexible properties. However, the material of the lower substrate 110 is not limited to this.

[0117] The lower substrate 110 is a ductile substrate and can reversibly expand and contract. In addition, the lower substrate 110 can have an elastic modulus in the range of several MPa to several hundred MPa (e.g., 0.5 MPa to 1 MPa).

[0118] The lower substrate 110 may have an active area A and an inactive area NA surrounding the active area A.

[0119] The effective area AA is the area on the display device 100 where an image is displayed. Within the effective area AA, display elements and various driving elements for driving the display elements are provided. Within the effective area AA, multiple pixels, each comprising multiple sub-pixels, are provided. The multiple pixels are provided within the effective area AA and include multiple display elements. Each of the multiple sub-pixels can be connected to various lines. For example, each of the multiple sub-pixels can be connected to various lines such as gating lines, data lines, high-potential power lines, low-potential power lines, and reference voltage lines.

[0120] The inactive area NA can be a region adjacent to and surrounding the active area AA. The inactive area NA is a region where no image is displayed, and lines and circuit units can be formed within it. For example, multiple pads can be set in the inactive area NA. Each pad can be connected to each of multiple sub-pixels set in the active area AA.

[0121] Multiple pixel substrates 111 and multiple non-pixel substrates 121 are disposed on a lower substrate 110. The multiple pixel substrates 111 can be disposed in the effective area AA of the lower substrate 110, and the multiple non-pixel substrates 121 can be disposed in the ineffective area NA of the lower substrate 110. Although Figure 1 A plurality of non-pixel substrates 121 are shown disposed to the left of the effective region AA in the ineffective region NA, but this disclosure is not limited thereto. The plurality of non-pixel substrates 121 may be disposed in any region of the ineffective region NA.

[0122] The plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 are rigid substrates and are spaced apart from each other to be independently disposed on the lower substrate 110. The plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 may be more rigid than the lower substrate 110. That is, the lower substrate 110 may be more ductile than the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121. Furthermore, the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 may be more rigid than the lower substrate 110.

[0123] The plurality of pixel substrates 111 and the plurality of non-pixel substrates 121, which are rigid substrates, can be made of a flexible plastic material. For example, the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 can be made of polyimide (PI), polyacrylate, polyacetate, etc. Here, the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 can be made of the same material, but are not limited thereto. The plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 can also be made of different materials from each other.

[0124] The modulus of the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 can be 1000 times or more the modulus of the lower substrate 110, but is not limited thereto. For example, depending on the transparency, the elastic modulus of the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 can be from 2 GPa to 9 GPa. More specifically, when the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 are transparent, the elastic modulus can be 2 GPa. Furthermore, when the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 are opaque, the elastic modulus can be 9 GPa, but this disclosure is not limited thereto. Therefore, the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121 can be a plurality of rigid substrates having rigidity compared to the lower substrate 110.

[0125] COF 130 is a thin film on a ductile base film 131, containing various components, and provides signals to multiple sub-pixels in the active area AA. COF 130 can be bonded to multiple pads on multiple non-pixel substrates 121 disposed in the non-active area NA. Furthermore, COF 130 provides power supply voltage, data voltage, gating voltage, etc., to each of the multiple sub-pixels in the active area AA via the pads. COF 130 includes a base film 131 and a driver IC 132. Additionally, various components can be additionally disposed on COF 130.

[0126] The base film 131 is used to support the driver IC 132 of the COF 130. The base film 131 can be made of an insulating material. For example, the base film 131 can be made of a flexible insulating material.

[0127] The driver IC 132 is configured to process data for displaying images and drive signals for processing the data. Figure 1 The method of mounting driver IC 132 via COF 130 is shown, but this disclosure is not limited thereto. Driver IC 132 can also be mounted via chip-on-glass (COG) method, tape-on-package (TCP) method, etc.

[0128] Figure 1 A non-pixel substrate 121 is shown disposed above the effective area AA in the ineffective area NA, corresponding to the pixel substrates 111 disposed in a row within the effective area AA. Furthermore, Figure 1 The COF 130 is shown for a non-pixel substrate 121. However, this disclosure is not limited thereto. That is, the non-pixel substrate 121 and COF 130 can be configured to correspond to pixel substrates 111 in a plurality of rows.

[0129] Control units such as IC chips and circuits can be mounted on the printed circuit board 140. Furthermore, memory, processors, and the like can also be mounted on the printed circuit board 140. The printed circuit board 140 is configured to transmit signals used to drive the display element from the control unit to the display element. Although Figure 1 The example shown uses three COF 130s, but the number of COF 130s is not limited to this.

[0130] In the following text, reference will be made to Figure 2 and Figure 3 A display device 100 according to an exemplary embodiment of the present disclosure will be described in more detail.

[0131] <Planar and Cross-sectional Structures>

[0132] Figure 2This is an enlarged plan view of a display device according to an exemplary embodiment of the present disclosure. Figure 3 yes Figure 2 A schematic cross-sectional view of the subpixel. For ease of description, reference will also be made below. Figure 1 .

[0133] Reference Figure 1 and Figure 2 Multiple pixel substrates 111 are disposed on the lower substrate 110 within the effective area AA. The multiple pixel substrates 111 are arranged to be spaced apart from each other on the lower substrate 110. For example, as... Figure 1 and Figure 2 As shown, multiple pixel substrates 111 can be arranged in a matrix on the lower substrate 110, but are not limited thereto.

[0134] Reference Figure 1 and Figure 2 Multiple sub-pixels SPX constituting multiple pixels PX can be disposed in multiple pixel substrates 111. Furthermore, a gate driver GD can be mounted on a non-pixel substrate 121 located to the left of the effective region AA. When manufacturing various components on the pixel substrate 111, the gate driver GD can be formed on the non-pixel substrate 121 in a gate-in-panel (GIP) manner. Therefore, various circuit components constituting the gate driver GD (e.g., various transistors, capacitors, and lines) can be disposed on the multiple non-pixel substrates 121. However, this disclosure is not limited thereto. The gate driver GD can also be mounted in a chip-on-film (COF) manner. Multiple non-pixel substrates 121 can also be disposed in a non-effective region NA located to the right of the effective region AA. Furthermore, the gate driver GD can also be mounted on multiple non-pixel substrates 121 located to the right of the effective region AA.

[0135] Reference Figure 1 The plurality of non-pixel substrates 121 can have a larger size than the plurality of pixel substrates 111. Specifically, each of the plurality of non-pixel substrates 121 can have a larger size than each of the plurality of pixel substrates 111. As described above, a gate driver GD is disposed on each of the plurality of non-pixel substrates 121. For example, a stage of the gate driver GD can be disposed on each of the plurality of non-pixel substrates 121. Therefore, since the area occupied by the various circuit components constituting a stage of the gate driver GD is relatively larger than the area of ​​the pixel substrate 111 on which the pixel PX is disposed, the size of each of the plurality of non-pixel substrates 121 can be larger than the size of each of the plurality of pixel substrates 111.

[0136] Reference Figure 1 and Figure 2Multiple connecting members 120 are disposed between multiple pixel substrates 111, multiple non-pixel substrates 121, or between multiple pixel substrates 111 and multiple non-pixel substrates 121. The multiple connecting members 120 are used to connect adjacent pixel substrates 111, adjacent non-pixel substrates 121, or adjacent pixel substrates 111 and non-pixel substrates 121. The multiple connecting members 120 may also be referred to as connecting substrates. The multiple connecting members 120 may be made of the same material as the pixel substrates 111 or non-pixel substrates 121, and may be integrally formed simultaneously with the pixel substrates 111 or non-pixel substrates 121. However, this disclosure is not limited thereto.

[0137] Reference Figure 2 Multiple connecting members 120 have curved shapes. For example, such as... Figure 2 As shown, the plurality of connecting members 120 can have a sinusoidal shape. However, the shape of the plurality of connecting members 120 is not limited to this. The plurality of connecting members 120 can have various shapes. For example, the plurality of connecting members 120 can extend in a zigzag manner, or the plurality of rhomboid substrates can extend by connecting to each other at their vertices. Figure 2 The number and shape of the multiple connecting members 120 shown are provided by way of example. The number and shape of the multiple connecting members 120 can vary according to the design.

[0138] Reference Figure 2 Multiple connection lines 180 are arranged in a straight line on multiple pixel substrates 111. Specifically, each of the multiple first connection lines 181 and multiple second connection lines 182 can be continuously formed on multiple connection members 120 to connect one end of the multiple pixel substrates 111 to the other end.

[0139] Reference Figure 2 and Figure 3 Multiple connection lines 180 on multiple connection members 120 have shapes corresponding to the multiple connection members 120. That is, the multiple connection lines 180 can have a sinusoidal shape. The multiple connection lines 180 are electrically connected to pads 170 disposed on adjacent pixel substrates 111 in multiple pixel substrates 111. Each of the multiple connection lines 180 extends in a curved shape rather than a straight line between the pads 170. However, for example, as Figure 2 As shown, the shape of the multiple connecting lines 180 is not limited to this. The multiple connecting lines 180 can have various shapes. For example, the multiple connecting lines 180 can extend in a zigzag pattern, or the multiple diamond-shaped lines 180 can extend by connecting each other at their vertices.

[0140] Reference Figure 3Multiple inorganic insulating layers are disposed on multiple pixel substrates 111. For example, the multiple inorganic insulating layers may include a buffer layer 112, a gate insulating layer 113, and an interlayer insulating layer 114. However, this disclosure is not limited thereto. Various inorganic insulating layers may be further disposed on the multiple pixel substrates 111. One or more of the buffer layer 112, the gate insulating layer 113, and the interlayer insulating layer 114 may be omitted.

[0141] Reference Figure 3 A buffer layer 112 is disposed on the plurality of pixel substrates 111. The buffer layer 112 is formed on the plurality of pixel substrates 111 to protect the various components of the display device 100 from the penetration of moisture (H2O) and oxygen (O2) from the lower substrate 110 and the plurality of pixel substrates 111. The buffer layer 112 can be made of an insulating material. For example, the buffer layer 112 can be formed as a single inorganic layer or multiple inorganic layers such as silicon nitride (SiNx), silicon oxide (SiOx), and silicon oxynitride (SiON). However, depending on the structure or characteristics of the display device 100, the buffer layer 112 may be omitted.

[0142] In this case, the buffer layer 112 may be formed only in the region overlapping with the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121. As described above, the buffer layer 112 may be made of an inorganic material. Therefore, when the display device 100 is stretched, the buffer layer 112 may be easily damaged (e.g., easily broken). Therefore, the buffer layer 112 may not be formed in the region between the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121. The buffer layer 112 may be patterned into the shape of the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121, and formed only on the upper part of the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121. Therefore, in the display device 100 according to an exemplary embodiment of the present disclosure, the buffer layer 112 is formed only in the region overlapping with the plurality of pixel substrates 111 and the plurality of non-pixel substrates 121, which are rigid substrates. Therefore, even when the display device 100 is deformed (e.g., bent or stretched), damage to the buffer layer 112 can be suppressed.

[0143] Reference Figure 3 A transistor 150 is formed on the buffer layer 112, which includes a gate electrode 151, an active layer 152, a source electrode 153 and a drain electrode 154.

[0144] Reference Figure 3 The active layer 152 is disposed on the buffer layer 112. For example, the active layer 152 may be made of an oxide semiconductor. Alternatively, the active layer 152 may be made of amorphous silicon (a-Si), polycrystalline silicon (poly-Si), organic semiconductor, etc.

[0145] A gate insulating layer 113 is disposed on the active layer 152. The gate insulating layer 113 is configured to electrically insulate the gate electrode 151 from the active layer 152. Furthermore, the gate insulating layer 113 may be made of an insulating material. For example, the gate insulating layer 113 may be formed as a single inorganic layer or multiple inorganic layers of silicon nitride (SiNx) or silicon oxide (SiOx), but is not limited thereto.

[0146] A gate electrode 151 is disposed on the gate insulating layer 113. The gate electrode 151 is configured to overlap with the active layer 152. The gate electrode 151 can be made of any of a variety of metallic materials, such as molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). Alternatively, the gate electrode 151 can be made of an alloy of two or more of the above-mentioned metallic materials or layers thereof, but is not limited thereto.

[0147] An interlayer insulating layer 114 is disposed on the gate electrode 151. The interlayer insulating layer 114 is used to insulate the gate electrode 151 from the source electrode 153 and the drain electrode 154. The interlayer insulating layer 114 may also be made of an inorganic material, similar to the buffer layer 112. For example, the interlayer insulating layer 114 may be formed as a single inorganic layer or multiple inorganic layers of silicon nitride (SiNx) or silicon oxide (SiOx), but is not limited thereto.

[0148] Source electrode 153 and drain electrode 154, both in contact with active layer 152, are disposed on interlayer insulating layer 114. Source electrode 153 and drain electrode 154 are disposed on the same layer and spaced apart from each other. Source electrode 153 and drain electrode 154 can be electrically connected to active layer 152 to contact active layer 152. Source electrode 153 and drain electrode 154 can be made of any of various metallic materials, such as molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). Alternatively, source electrode 153 and drain electrode 154 can be made of alloys of two or more of the above metallic materials or multiple layers thereof, but are not limited thereto.

[0149] Furthermore, the gate insulating layer 113 and the interlayer insulating layer 114 can be patterned and formed only in the regions overlapping with the multiple pixel substrates 111. The gate insulating layer 113 and the interlayer insulating layer 114 can also be made of inorganic materials, similar to the buffer layer 112. Therefore, when the display device 100 is stretched, the gate insulating layer 113 and the interlayer insulating layer 114 may be easily damaged (e.g., easily cracked). Therefore, the gate insulating layer 113 and the interlayer insulating layer 114 may not be formed in the regions between the multiple pixel substrates 111. The gate insulating layer 113 and the interlayer insulating layer 114 can be patterned into the shape of the multiple pixel substrates 111 and formed only on the upper part of the multiple pixel substrates 111.

[0150] For ease of description, Figure 3 Only driving transistors, which can be included in the display device 100, are shown. However, switching transistors, capacitors, etc., may also be included in the display device 100. Furthermore, in this disclosure, transistor 150 is described as having a coplanar structure, but various types of transistors having a staggered structure, etc., may also be used.

[0151] Reference Figure 3 A power pad 171 is formed among a plurality of pads 170 on the interlayer insulating layer 114. The power pad 171 is used to transmit power signals to a plurality of sub-pixels SPX. The power signals can be transmitted from the power pad 171 to the pixel circuitry via lines formed on the pixel substrate 111. The power pad 171 may be formed on the same layer and of the same material as the source electrode 153 and the drain electrode 154, but is not limited thereto.

[0152] Reference Figure 3 Data pads 172, one of the multiple pads 170, are disposed on the interlayer insulating layer 114. Data pads 172 are used to transmit data signals to multiple sub-pixels (SPX). Data signals can be transmitted from data pads 172 to source electrodes 153 or drain electrodes 154 via data lines formed on the pixel substrate 111. Data pads 172 may be formed on the same layer as the source electrodes 153 and drain electrodes 154, but are not limited to this.

[0153] Reference Figure 3 A planarization layer 115 is formed on the transistor 150 and the interlayer insulating layer 114. The planarization layer 115 is used to planarize the upper part of the transistor 150. The planarization layer 115 can be formed as a single layer or multiple layers and can be made of organic materials. Therefore, the planarization layer 115 can also be called an organic insulating layer. For example, the planarization layer 115 can be made of acrylic organic materials, but is not limited thereto.

[0154] Reference Figure 3A planarization layer 115 is disposed between a plurality of pixel substrates 111 and the first connection lines 181 to cover the upper and side surfaces of the buffer layer 112, the gate insulating layer 113, and the interlayer insulating layer 114. Furthermore, the planarization layer 115 surrounds the buffer layer 112, the gate insulating layer 113, and the interlayer insulating layer 114 together with the plurality of pixel substrates 111. Specifically, the planarization layer 115 may be configured to cover the upper and side surfaces of the interlayer insulating layer 114, the side surface of the gate insulating layer 113, the side surface of the buffer layer 112, and a portion of the upper surface of the plurality of pixel substrates 111. Therefore, the planarization layer 115 between the plurality of pixel substrates 111 and the plurality of first connection lines 181 can compensate for the steps between the side surfaces of the buffer layer 112, the gate insulating layer 113, and the interlayer insulating layer 114. Furthermore, the planarization layer 115 can enhance the adhesion strength between the planarization layer 115 and the first connection lines 181 disposed on the side surfaces of the planarization layer 115.

[0155] Meanwhile, the tilt angle of the side surface of the planarization layer 115 can be smaller than the tilt angle of the side surfaces of the buffer layer 112, the gate insulating layer 113, and the interlayer insulating layer 114. However, this disclosure is not limited thereto.

[0156] In some exemplary embodiments, a passivation layer may be formed between the transistor 150 and the planarization layer 115. That is, a passivation layer may be formed covering the transistor 150 to protect the transistor 150 from the penetration of moisture and oxygen. The passivation layer may be made of inorganic materials and may be formed as a single layer or multiple layers, but is not limited thereto.

[0157] Reference Figure 2 and Figure 3 The connection line 180 refers to the line that is electrically connected to the pads 170 disposed on the multiple pixel substrates 111 or the multiple non-pixel substrates 121. The connection line 180 is disposed on the pixel substrates 111 and the multiple connection members 120.

[0158] The connection line 180 includes a first connection line 181 and a second connection line 182. The first connection line 181 and the second connection line 182 are disposed on a plurality of pixel substrates 111 and a plurality of connection members 120. Specifically, the first connection line 181 refers to a line disposed on a connection member 120 extending along the X-axis direction, which is a first direction, among the plurality of connection members 120 and the plurality of pixel substrates 111. The second connection line 182 refers to a line disposed on a connection member 120 extending along the Y-axis direction, which is a second direction, among the plurality of connection members 120 and the plurality of pixel substrates 111. The connection line 180 may be made of a metallic material such as copper (Cu), aluminum (Al), titanium (Ti), or molybdenum (Mo). Alternatively, the connection line 180 may have a multilayer structure of metallic materials, such as copper / molybdenum-titanium (Cu / MoTi), titanium / aluminum / titanium (Ti / Al / Ti), etc., but is not limited thereto.

[0159] Reference Figure 1 and Figure 2 The first connection line 181 can connect pads on two pixel substrates 111 arranged side-by-side along the X-axis. Each of the first connection lines 181 can be used as a gating line, a light-emitting signal line, a high-potential power line, or a low-potential power line, but is not limited thereto. For example, as Figure 3 As shown, the first connection line 181 can be used as a power line for transmitting high-potential voltages in the power supply voltage. Furthermore, the first connection line 181 can electrically connect to power pads 171 on two pixel substrates 111 arranged side-by-side along the X-axis.

[0160] Reference Figure 2 The second connection line 182 can connect two pixel substrates 111 arranged side by side along the Y-axis direction among a plurality of pixel substrates 111. Each second connection line 182 can be used as a data line, a high-potential power line, a low-potential power line, or a reference voltage line, but is not limited thereto. For example, the second connection line 182 can be used as a data line and can electrically connect data lines on two pixel substrates 111 arranged side by side along the Y-axis direction.

[0161] Reference Figure 1 The connection line 180 may also include lines connecting pads on multiple pixel substrates 111 and multiple non-pixel substrates 121, or connecting pads on two non-pixel substrates 121 arranged side by side among the multiple non-pixel substrates 121.

[0162] Each first connection line 181 can contact the upper and side surfaces of the planarization layer 115 disposed on the pixel substrate 111, and can extend to the upper surface of the connection member 120. In addition, each second connection line 182 can extend from the pixel substrate 111 to the upper surface of the inorganic insulating layer and the connection member 120.

[0163] Reference Figure 3 Independent connection pads CP1 and common connection pads CP2 are provided on the planarization layer 115. Independent connection pads CP1 and common connection pads CP2 are used to transmit signals to multiple light-emitting diodes (LEDs) 160.

[0164] Reference Figure 2 and Figure 3 Multiple independent connection pads CP1 are provided on the planarization layer 115. These independent connection pads CP1 can be connected to transistors 150 and can transmit voltage to multiple LEDs 160. Therefore, the multiple independent connection pads CP1 can serve as anodes.

[0165] Multiple independent connection pads CP1 can be formed on the planarization layer 115 using the same process as the connection line 180. That is, the multiple independent connection pads CP1 can be formed of the same material as the connection line 180 and disposed on the same layer, but are not limited thereto.

[0166] The number of independent connection pads CP1 disposed on a pixel substrate 111 can be equal to the number of LEDs 160 disposed on a pixel substrate 111. For example, as Figure 2 As shown, if three LEDs 160 are provided on a pixel substrate 111, three independent connection pads CP1 can be provided on the pixel substrate 111 to apply a separate voltage to each of the LEDs 160.

[0167] Reference Figure 2 and Figure 3 A common connection pad CP2 is disposed on the planarization layer 115. The common connection pad CP2 can be connected to the first connection line 181 and can transmit voltage to multiple LEDs 160. Therefore, the common connection pad CP2 can be used as a cathode.

[0168] The number of common connection pads CP2 disposed on a pixel substrate 111 can be one, regardless of the number of multiple LEDs 160 disposed on the pixel substrate 111. For example, as Figure 2 As shown, if three LEDs 160 are disposed on a pixel substrate 111, the common connection pad CP2 only needs to apply a low potential power to the three LEDs 160 equally. Therefore, a single common connection pad CP2 can be disposed on a pixel substrate 111 and can be electrically connected to three LEDs 160.

[0169] The distance d1 between the independent connection pad CP1 and the common connection pad CP2 can be determined based on the distance between the n-electrode 165 and the p-electrode 164 of the LED 160. The p-electrode 164 of the LED 160 needs to be electrically connected to the independent connection pad CP1, and the n-electrode 165 of the LED 160 needs to be electrically connected to the common connection pad CP2. Neither the n-electrode 165 nor the p-electrode 164 of the LED 160 should be electrically connected to both the independent connection pad CP1 and the common connection pad CP2. Therefore, the distance d1 between the independent connection pad CP1 and the common connection pad CP2 can be determined by considering the distance between the n-electrode 165 and the p-electrode 164 in the LED 160.

[0170] The distance d2 between the first connection line 181, which is adjacent to the common connection pad CP2 and transmits a high-potential voltage, and the common connection pad CP2 can be set to a minimum. (Refer to...) Figure 2 and Figure 3 The first connection line 181, which transmits high-potential voltage, can be disposed on the planarization layer 115 below the common connection pad CP2 along the Y-axis direction. As the display device 100 is developed to have high resolution, it is advantageous to minimize the size of each pixel substrate 111. Therefore, it is also advantageous to minimize the distance between components disposed on the pixel substrate 111, taking into account process margins. Thus, it is possible to design the distance d2 between the first connection line 181, which is adjacent to the common connection pad CP2, and the common connection pad CP2, to be minimized, taking into account process margins.

[0171] At the same time, despite Figure 3 Although not shown in the diagram, dams can also be provided on the independent connection pad CP1, the common connection pad CP2, the connection line 180, and the planarization layer 115. Dams can be used to distinguish between adjacent sub-pixels SPX.

[0172] Reference Figure 3 LED 160 is disposed on independent connection pad CP1 and common connection pad CP2. LED 160 includes an n-type layer 161, an active layer 162, a p-type layer 163, an n-electrode 165, and a p-electrode 164. The LED 160 of the display device 100 according to an exemplary embodiment of the present disclosure has a flip-chip structure, wherein the n-electrode 165 and the p-electrode 164 are formed on one of its surfaces.

[0173] An n-type layer 161 can be formed by implanting n-type impurities into gallium nitride (GaN), which has excellent crystallinity. The n-type layer 161 can be disposed on a separate substrate made of a light-transmitting material.

[0174] An active layer 162 is disposed on the n-type layer 161. The active layer 162 is the light-emitting layer that emits light in the LED 160 and can be made of a nitride semiconductor such as indium gallium nitride (InGaN). A p-type layer 163 is disposed on the active layer 162. The p-type layer 163 can be formed by implanting p-type impurities into gallium nitride (GaN).

[0175] As described above, an LED 160 according to an exemplary embodiment of the present disclosure is manufactured by sequentially stacking an n-type layer 161, an active layer 162, and a p-type layer 163, and then etching predetermined regions of these layers to form n-electrodes 165 and p-electrodes 164. In this case, the predetermined regions are spaces that separate the n-electrodes 165 and p-electrodes 164 from each other, and are etched to expose a portion of the n-type layer 161. In other words, the surface of the LED 160 on which the n-electrodes 165 and p-electrodes 164 are to be disposed may be uneven and may have different height levels.

[0176] As described above, the n-electrode 165 is disposed on the etched area (i.e., on the n-type layer 161 exposed by etching). The n-electrode 165 can be made of a conductive material. Furthermore, the p-electrode 164 is disposed on the non-etched area (i.e., on the p-type layer 163). The p-electrode 164 can also be made of a conductive material. For example, the p-electrode 164 can be made of the same material as the n-electrode 165.

[0177] An adhesive layer AD is provided on the upper surfaces of the independent connection pad CP1 and the common connection pad CP2, and between the independent connection pad CP1 and the common connection pad CP2. Therefore, the LED 160 can be bonded to the independent connection pad CP1 and the common connection pad CP2. In this case, the n-electrode 165 can be provided on the common connection pad CP2, and the p-electrode 164 can be provided on the independent connection pad CP1.

[0178] The adhesive layer AD can be a conductive adhesive layer formed by dispersing conductive balls CB in the base component BR. Therefore, when heat or pressure is applied to the adhesive layer AD, the conductive balls CB are electrically connected to have conductive properties in the portion of the adhesive layer AD where heat or pressure is applied.

[0179] When the electrodes of LED 160 are bonded to the common connection pad CP2 and the independent connection pad CP1, conductive balls CB mixed in the base component BR can be used to electrically connect the electrodes of LED 160 to the common connection pad CP2 and the independent connection pad CP1. The conductive balls CB can be made of a conductive metal such as gold (Au) with ductility within a material such as nickel (Ni), but are not limited thereto. Furthermore, the conductive balls CB can have a diameter of approximately 4 μm before bonding, but this disclosure is not limited thereto. When the electrodes of LED 160 are bonded to the connection pads, the material covering the internal conductive metal can be damaged by heat and pressure, and the internal conductive metal can be cooled and hardened. Therefore, the electrodes of LED 160 can be electrically connected to the connection pads.

[0180] The base component BR can be an adhesive component with adhesive and insulating properties. The base component BR can be, for example, a thermosetting adhesive, but is not limited thereto.

[0181] Reference Figure 3 The n-electrode 165 is electrically connected to the common connection pad CP2, for example, via the adhesive layer AD. Furthermore, the p-electrode 164 is electrically connected to the independent connection pad CP1 via the adhesive layer AD. The adhesive layer AD, containing conductive balls CB, can be applied to the upper surfaces of the independent connection pad CP1 and the common connection pad CP2 using an inkjet printing method or the like. Then, the LED 160 can be transferred onto the adhesive layer AD. Subsequently, the LED 160 can be pressed and heated, thereby electrically bonding and connecting the independent connection pad CP1 to the p-electrode 164 via the conductive balls CB, and electrically bonding and connecting the common connection pad CP2 to the n-electrode 165. Here, the conductive balls CB can be directed to be disposed only between the n-electrode 165 and the common connection pad CP2, and between the p-electrode 164 and the independent connection pad CP1. Simultaneously, the remaining portions of the adhesive layer AD, except for the portion between the n-electrode 165 and the common connection pad CP2, and the portion of the adhesive layer AD with conductive balls CB disposed between the p-electrode 164 and the independent connection pad CP1, have insulating properties. In addition, the adhesive layer AD can also be separately applied to each of the independent connection pads CP1 and the common connection pads CP2.

[0182] As described above, a display device 100 according to an exemplary embodiment of the present disclosure has a structure in which an LED 160 is disposed on a lower substrate 110 on which a transistor 150 is disposed. Therefore, when the display device 100 is turned on, different voltage levels applied to each of the independent connection pads CP1 and the common connection pad CP2 are transmitted to the n electrode 165 and the p electrode 164, respectively. Thus, the LED 160 emits light.

[0183] Reference Figure 3An upper substrate US is disposed on LED 160 and lower substrate 110.

[0184] The upper substrate US is used to support various components disposed below the upper substrate US. Specifically, the upper substrate US can be formed by coating and hardening the material of the upper substrate US on the lower substrate 110 and the pixel substrate 111. Therefore, the upper substrate US can be configured to contact the lower substrate 110, the pixel substrate 111, the connecting member 120, and the connecting line 180.

[0185] The upper substrate US is a ductile substrate and can be made of a flexible or stretchable insulating material. The upper substrate US is ductile and can reversibly expand and contract. Furthermore, the upper substrate US can have an elastic modulus ranging from a few MPa to several hundred MPa. Additionally, the upper substrate US can have a ductile breaking rate of 100% or higher. The upper substrate US can have a thickness from 10 μm to 1 mm, but is not limited to this.

[0186] The upper substrate US can be made of the same material as the lower substrate 110. For example, the upper substrate US can be made of silicone rubber such as polydimethylsiloxane (PDMS) and elastomers such as polyurethane (PU) and polytetrafluoroethylene (PTFE). Therefore, the upper substrate US can be flexible. However, the material of the upper substrate US is not limited to this.

[0187] At the same time, despite Figure 3 Although not shown, a polarizing layer may also be provided on the upper substrate US. The polarizing layer can be used to polarize light incident from outside the display device 100 and reduce the reflection of external light. In addition, other optical films may be provided on the upper substrate US instead of a polarizing layer.

[0188] In the following text, reference will be made to Figure 4 as well as Figures 1 to 3 The common connection pad CP2 is described in more detail.

[0189] <Multi-layer structure of common connection pads>

[0190] Figure 4 This is a schematic enlarged plan view of the pixel substrate of a display device according to an exemplary embodiment of the present disclosure.

[0191] Reference Figure 3 and Figure 4 The common connection pad CP2 includes a lower common connection pad CP21 and an upper common connection pad CP22. In other words, the common connection pad CP2 can have a multi-layer structure.

[0192] The lower common connection pad CP21 of the common connection pad CP2 is disposed on the planarization layer 115. The lower common connection pad CP21 can be electrically connected to the first connection line 181 and multiple LEDs 160.

[0193] The lower common connection pad CP21 can be formed using the same process as the first connection line 181. That is, the lower common connection pad CP21 can be formed on the same layer as the first connection line 181 using the same material, but is not limited to this. Here, the lower common connection pad CP21 can be integrally formed with the first connection line 181 used for transmitting low-potential power. However, it is advantageous that multiple LEDs 160 are disposed on and electrically connected to the lower common connection pad CP21. Therefore, the common connection pad CP21 can have a larger width than the first connection line 181. The lower common connection pad CP21 can be made of, for example, copper (Cu), but is not limited to this. The material of the lower common connection pad CP21 can vary depending on the design. Here, the lower common connection pad CP21 can have a thickness of approximately 3000 Å to approximately 10000 Å, but is not limited to this.

[0194] The upper common connection pad CP22 of the common connection pad CP2 is disposed on the lower common connection pad CP21. Here, the upper common connection pad CP22 can be disposed on the edge of the lower common connection pad CP21. That is, as... Figure 4 As shown, the upper common connection pad CP22 can be arranged in the form of a closed curve on the edge of the lower common connection pad CP21. However, this disclosure is not limited to this. The upper common connection pad CP22 can also be arranged in multiple patterns on the edge of the lower common connection pad CP21. Although Figure 4 The upper common connection pad CP22 is shown to have a rectangular cross-sectional shape, but the cross-sectional shape of the upper common connection pad CP22 is not limited to this.

[0195] The upper common connection pad CP22 can be made of a different material than the lower common connection pad CP21. Here, the upper common connection pad CP22 can be made of a material that has better adhesion to the electrodes of the multiple LEDs 160 than it does to the lower common connection pad CP21. Therefore, during the process of repairing the multiple LEDs 160, the upper common connection pad CP22 can be easily separated from the lower common connection pad CP21.

[0196] For example, if the lower common connection pad CP21 is made of copper (Cu) and the electrodes of the multiple LEDs 160 are made of gold (Au), then the upper common connection pad CP22 can be made of gold (Au). That is, the material of the upper common connection pad CP22 can be different from the material of the lower common connection pad CP21, but can be the same as the material of the electrodes of the multiple LEDs 160. Therefore, due to the high adhesion between homogeneous materials, the adhesion of the upper common connection pad CP22 to the electrodes of the multiple LEDs 160 can be higher than that to the lower common connection pad CP21. The upper common connection pad CP22 can be made of, for example, gold (Au), titanium (Ti), aluminum (Al), or molybdenum (Mo), but is not limited to these. Here, the upper common connection pad CP22 can have a thickness of approximately 20,000 Å, but is not limited to this.

[0197] When manufacturing the display device 100, if misalignment occurs in the transfer process used to electrically connect and bond individual connection pads CP1 and common connection pads CP2 to multiple LEDs 160, a repair process can be added to remove the misaligned LEDs 160 and transfer and bond new LEDs 160. Here, if the adhesion between the common connection pad CP2 bonded to the multiple LEDs 160 and the electrodes of the multiple LEDs 160 is too high, the common connection pad CP2 may be peeled off from the lower substrate 110 along with the multiple LEDs 160 when removing the LEDs 160. That is, the common connection pad CP2 is removed along with the misaligned LEDs 160 as described above. In this case, even if new LEDs 160 are transferred, they cannot be driven because they are not properly bonded. Therefore, the entire display device 100 is defective.

[0198] Therefore, in a display device 100 according to an exemplary embodiment of the present disclosure, the common connection pad CP2 has a multilayer structure including a lower common connection pad CP21 and an upper common connection pad CP22. Therefore, during a repair process, multiple LEDs 160 can be easily removed from the common connection pad CP2. Specifically, the upper common connection pad CP22, made of a material whose adhesion to the electrodes of the multiple LEDs 160 is higher than its adhesion to the lower common connection pad CP21, is disposed on the lower common connection pad CP21. Therefore, during a repair process, the upper common connection pad CP22 can be easily separated from the lower common connection pad CP21 along with the multiple LEDs 160. Furthermore, in some processes, both the upper common connection pad CP22 and the lower common connection pad CP21 can be disposed on the lower substrate 110 side, and only the LEDs 160 can be separated. Therefore, in a display device 100 according to an exemplary embodiment of the present disclosure, when repairing a misaligned LED 160, the common connection pad CP2 can be minimized from being stripped from the lower substrate 110 along with the LED 160.

[0199] Furthermore, in the manufacturing of the display device 100, in the transfer process for electrically connecting the individual connection pads CP1 and the common connection pad CP2 to a plurality of LEDs 160, an adhesive layer AD is used to simultaneously bond and electrically connect the plurality of LEDs 160 to the individual connection pads CP1 and the common connection pad CP2. The adhesive layer AD can be formed in a liquid state on the individual connection pads CP1 and the common connection pad CP2 and then cured by heat and / or pressure. Therefore, when the adhesive layer AD is in a liquid state, the plurality of LEDs 160 can move with the movement of the adhesive layer AD. Therefore, misalignment of the plurality of LEDs 160 relative to the individual connection pads CP1 and the common connection pad CP2 may occur. Furthermore, when the adhesive layer AD moves, the LEDs 160 may be misaligned between the common connection pad CP2, which has a relatively small distance between them, and the first connection line 181 for transmitting a high potential voltage. Therefore, the common connection pad CP2 and the first connection line 181 may be electrically connected through the electrodes of the LEDs 160. In this case, dark spots may appear in the sub-pixels SPX, including LED 160.

[0200] Therefore, in a display device 100 according to an exemplary embodiment of the present disclosure, the common connection pad CP2 has a multilayer structure including a lower common connection pad CP21 and an upper common connection pad CP22. Therefore, misalignment of the LED 160 caused by movement of the adhesive layer AD can be minimized. Specifically, the upper common connection pad CP22 can be disposed along the edge of the lower common connection pad CP21, and the common connection pad CP2 can have a stepped difference. Therefore, even if the adhesive layer AD moves, the movement of the conductive balls CB in the adhesive layer AD and the electrodes of the LED 160 can be limited by the upper common connection pad CP22. Therefore, in a display device 100 according to an exemplary embodiment of the present disclosure, the common connection pad CP2 with a stepped structure can be used to suppress the occurrence of misalignment of the LED 160 and the occurrence of dark spots caused by misalignment.

[0201] <Multi-layer structure with independently connected pads>

[0202] Figure 5A This is a schematic cross-sectional view of a pixel substrate of a display device according to another exemplary embodiment of the present disclosure. Figure 5B This is an enlarged plan view of a pixel substrate of a display device according to another exemplary embodiment of the present disclosure. In addition to the independently connected pad CP1, Figure 5A and Figure 5B The display device 500 shown and Figures 1 to 4 The display device 100 shown is essentially the same. Therefore, its redundant description will be omitted.

[0203] Reference Figure 5A and Figure 5B According to another exemplary embodiment of the present disclosure, the display device 500 has a plurality of lower independent connection pads CP11 and a plurality of upper independent connection pads CP12. The upper independent connection pads CP12 may be disposed on the lower independent connection pads CP11. Furthermore, the upper independent connection pads CP12 may be formed in a shape corresponding to the upper common connection pad CP22 and disposed on the lower independent connection pads CP11. Therefore, the upper independent connection pads CP12 may be disposed on the edges of the lower independent connection pads CP11, and the plurality of upper independent connection pads CP12 may partially contact the electrodes of the plurality of LEDs 160.

[0204] In the multilayer structure of the independent connection pads CP1, multiple lower independent connection pads CP11 are disposed on the planarization layer 115. The multiple lower independent connection pads CP11 can be electrically connected to the first connection line 181 and multiple LEDs 160.

[0205] Multiple lower independent connection pads CP11 can be formed using the same process as the lower common connection pad CP21. That is, the multiple lower independent connection pads CP11 can be formed on the same layer as the lower common connection pad CP21 using the same material, but are not limited to this. The multiple lower independent connection pads CP11 can be made of, for example, copper (Cu), but are not limited to this. The material of the multiple lower independent connection pads CP11 can vary depending on the design. Here, the multiple lower independent connection pads CP11 can have a thickness of approximately 3000 Å to approximately 10000 Å, but are not limited to this.

[0206] The upper independent connection pad CP12 is positioned on the lower independent connection pad CP11. Here, the upper independent connection pad CP12 can be positioned on the edge of the lower independent connection pad CP11. That is, as... Figure 5B As shown, the upper independent connection pad CP12 can be disposed on the edge of the lower independent connection pad CP11 in the form of a closed curve. However, this disclosure is not limited thereto. The upper independent connection pad CP12 can also be disposed on the edge of the lower independent connection pad CP11 in the form of multiple patterns. An upper independent connection pad CP12 having multiple patterns corresponding to the pattern of the upper common connection pad CP22 can be disposed on the lower independent connection pad CP11.

[0207] The upper independent connection pad CP12 can be made of a different material than the lower independent connection pad CP11. Here, the upper independent connection pad CP12 can be made of a material that has better adhesion to the electrodes of the multiple LEDs 160 than it does to the lower independent connection pad CP11. Therefore, during the process of repairing the multiple LEDs 160, the upper independent connection pad CP12 can be easily separated from the lower independent connection pad CP11.

[0208] For example, if the lower independent connection pad CP11 is made of copper (Cu) and the electrodes of the multiple LEDs 160 are made of gold (Au), then the upper independent connection pad CP12 can be made of gold (Au). That is, the material of the upper independent connection pad CP12 can be different from the material of the lower independent connection pad CP11, but can be the same as the material of the electrodes of the multiple LEDs 160. Therefore, due to the high adhesion between homogeneous materials, the adhesion of the upper independent connection pad CP12 to the electrodes of the LEDs 160 can be higher than that to the lower independent connection pad CP11. The upper independent connection pad CP12 can be made of, for example, gold (Au), titanium (Ti), aluminum (Al), or molybdenum (Mo), but is not limited to these. Here, the upper independent connection pad CP12 can have a thickness of approximately 20,000 Å, but is not limited to this.

[0209] In a display device 500 according to another exemplary embodiment of the present disclosure, a plurality of independent connection pads CP1 have a multilayer structure including a plurality of lower independent connection pads CP11 and a plurality of upper independent connection pads CP12. Therefore, during a repair process, a plurality of LEDs 160 can be easily removed from the plurality of independent connection pads CP1. Specifically, upper independent connection pads CP12, made of a material whose adhesion to the electrodes of the plurality of LEDs 160 is higher than its adhesion to the lower independent connection pads CP11, are disposed on the lower independent connection pads CP11. Therefore, during a repair process, the upper independent connection pads CP12 can be easily separated from the lower independent connection pads CP11 along with the plurality of LEDs 160. Furthermore, in some processes, both the plurality of upper independent connection pads CP12 and the plurality of lower independent connection pads CP11 can be disposed on the lower substrate 110 side, and only the LEDs 160 can be separated. Therefore, in a display device 500 according to another exemplary embodiment of the present disclosure, when a misaligned LED 160 is repaired, the individual connection pad CP1 can be minimized from being peeled off from the lower substrate 110 along with the LED 160.

[0210] Furthermore, in a display device 500 according to another exemplary embodiment of the present disclosure, the plurality of independent connection pads CP1 have a multilayer structure including a plurality of lower independent connection pads CP11 and a plurality of upper independent connection pads CP12. Therefore, misalignment of the LED 160 caused by movement of the adhesive layer AD can be minimized. Specifically, the upper independent connection pads CP12 can be disposed along the edge of the lower independent connection pads CP11, and the independent connection pads CP1 can have a stepped difference. Therefore, even if the adhesive layer AD moves, the movement of the conductive balls CB in the adhesive layer AD and the electrodes of the LED 160 can be limited by the plurality of upper independent connection pads CP12. Therefore, in the display device 500 according to another exemplary embodiment of the present disclosure, the plurality of independent connection pads CP1 with a stepped structure can be used to suppress the occurrence of misalignment of the LED 160 and the occurrence of dark spots caused by misalignment.

[0211] <Pattern of the upper common connection pad>

[0212] Figure 6 This is an enlarged plan view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure. Except for the shape of the upper common connection pad CP22, Figure 6 The display device 600 shown and Figure 5A and Figure 5B The display device 500 shown is essentially the same. Therefore, redundant descriptions will be omitted.

[0213] Reference Figure 6 According to another exemplary embodiment of the present disclosure, the upper common connection pad CP22 of the display device 600 may also be disposed on the lower common connection pad CP21 corresponding to the space between a plurality of independent connection pads CP1. Therefore, the upper common connection pad CP22 may also be disposed in the space between a plurality of LEDs 160.

[0214] In another exemplary embodiment of the display device 600 according to this disclosure, the upper common connection pad CP22 is further disposed on the lower common connection pad CP21 corresponding to the space between a plurality of independent connection pads CP1. Therefore, frictional force can be provided to the electrodes of the plurality of LEDs 160. Thus, the electrodes of the plurality of LEDs 160 do not deviate from the area where the upper common connection pad CP22 is located. For example, even if the plurality of LEDs 160 are located from... Figure 6 The state shown can be slid in the left-right direction, which can also guide the movement of multiple LEDs 160 within the area defined by the upper common connection pad CP22. Therefore, the deviation of multiple LEDs 160 from the upper common connection pad CP22 can be suppressed. Therefore, even if the adhesive layer AD moves, the movement of the conductive ball CB in the adhesive layer AD and the electrodes of the LEDs 160 can be restricted by the upper common connection pad CP22. Therefore, in the display device 600 according to another exemplary embodiment of the present disclosure, the upper common connection pad CP22 is further disposed at a position corresponding to the space between multiple individual connection pads CP1. Therefore, misalignment of the LEDs 160 can be suppressed.

[0215] Figure 7 This is an enlarged plan view of a pixel substrate of a display device 700 according to yet another exemplary embodiment of the present disclosure. Except for the shape of the upper common connection pad CP22, Figure 7 The display device 700 shown is Figure 6 The display device 600 shown is essentially the same. Therefore, its redundant description will be omitted.

[0216] Reference Figure 7 According to another exemplary embodiment of the present disclosure, the upper common connection pad CP22 of the display device 700 may have a grid pattern. That is, the upper common connection pad CP22 may be arranged in a grid pattern on the lower common connection pad CP21. Here, the upper common connection pad CP22 may be arranged on the lower common connection pad CP21 from... Figure 7The state shown extends in both the vertical and horizontal directions. For example, the upper common connection pad CP22 may include a portion disposed on the lower common connection pad CP21 parallel to the extending direction of the common connection pad CP2. Furthermore, the upper common connection pad CP22 may include a portion disposed on the lower common connection pad CP21 perpendicular to the extending direction of the common connection pad CP2. In another exemplary embodiment of the display device 700 according to this disclosure, the upper common connection pad CP22 is disposed on the lower common connection pad CP21 in a grid pattern. Therefore, greater frictional force can be provided to the electrodes of the plurality of LEDs 160. Therefore, the electrodes of the plurality of LEDs 160 may not deviate from the area where the upper common connection pad CP22 is located. For example, even if the plurality of LEDs 160 slide, the conductive ball CB can be engaged in the holes of the grid pattern of the upper common connection pad CP22. Therefore, the plurality of LEDs can move within the area defined by the upper common connection pad CP22, and the deviation of the plurality of LEDs 160 from the common connection pad CP2 can be suppressed. Therefore, even if the adhesive layer AD moves, the movement of the conductive balls CB in the adhesive layer AD and the electrodes of the LED 160 can be limited by the upper common connection pad CP22. Therefore, in another exemplary embodiment of the display device 700 according to this disclosure, the upper common connection pad CP22 is provided in a grid pattern on the lower common connection pad CP21. Therefore, misalignment of the LED 160 can be suppressed.

[0217] <Insulating layer>

[0218] Figure 8 This is a schematic cross-sectional view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure. Apart from the placement of the insulating layer IL1, Figure 8 The display device 800 shown is Figure 5A and Figure 5B The display device 500 shown is essentially the same. Therefore, redundant descriptions will be omitted.

[0219] Reference Figure 8 According to another exemplary embodiment of the present disclosure, the display device 800 may include an insulating layer IL1. The insulating layer IL1 may be disposed on the first connection line 181. Specifically, the insulating layer IL1 may be disposed on the power line PL in the first connection line 181 for transmitting high-potential power.

[0220] The insulating layer IL1 can be made of a material with insulating properties. The insulating layer IL1 can be, for example, an inorganic layer of silicon nitride (SiNx) or silicon oxide (SiOx), but is not limited to these. The material of the insulating layer IL1 can vary depending on the design. Here, the insulating layer IL1 can have a thickness of about 10,000 Å to about 20,000 Å, but is not limited to these.

[0221] The insulating layer IL1 may include multiple insulating patterns. The multiple insulating patterns of the insulating layer IL1 may have various shapes, such as columnar, linear, or grid-like.

[0222] The distance between multiple insulating patterns in insulating layer IL1 can be smaller than the size of the conductive ball CB in adhesive layer AD. For example, the distance between multiple insulating patterns in insulating layer IL1 can be smaller than the radius or diameter of the conductive ball CB in adhesive layer AD.

[0223] In a display device 800 according to yet another exemplary embodiment of the present disclosure, an insulating layer IL1 comprising a plurality of insulating patterns is disposed on a first connection line 181 serving as a high-potential power line. Therefore, misalignment of the LED 160 can be minimized. Specifically, if the LED 160 moves toward the first connection line 181 for transmitting high-potential power due to movement of the adhesive layer AD, the insulating pattern closest to the common connection pad CP2 among the plurality of insulating patterns can initially suppress the movement of the LED 160. Furthermore, when the LED 160 moves on the insulating layer IL1, all the plurality of insulating patterns provide frictional force, thereby limiting the movement of the LED 160. Therefore, in the display device 800 according to yet another exemplary embodiment of the present disclosure, misalignment of the LED 160 caused by movement of the adhesive layer AD can be suppressed.

[0224] Furthermore, in a display device 800 according to another exemplary embodiment of the present disclosure, an insulating layer IL1 is provided on a first connection line 181 serving as a high-potential power line. Therefore, even if the plurality of LEDs 160 are misaligned, connection between the LEDs 160 and the first connection line 181 serving as a power line for transmitting high-potential power can be suppressed. Even if the LEDs 160 are positioned on the first connection line 181 serving as a power line for transmitting high-potential power due to movement of the adhesive layer AD, the LEDs 160 can still be prevented from connecting to the first connection line 181 serving as a power line for transmitting high-potential power by means of the insulating layer IL1 provided on the first connection line 181. Therefore, in a display device 800 according to another exemplary embodiment of the present disclosure, the insulating layer IL1 can be used to suppress the occurrence of dark spots caused by both the LEDs 160 connecting to the common connection pad CP2 and the first connection line 181 serving as a power line for transmitting high-potential power.

[0225] Figure 9 This is a schematic cross-sectional view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure. Apart from the insulating layer IL2, Figure 9 The display device 900 shown and Figure 8The display device 800 shown is essentially the same. Therefore, its redundant description will be omitted.

[0226] Reference Figure 9 According to another exemplary embodiment of the present disclosure, the display device 900 may include an insulating layer IL2. The insulating layer IL2 may be disposed on the first connection line 181. Specifically, the insulating layer IL2 may be disposed on the power line PL in the first connection line 181 for transmitting high-potential power.

[0227] The insulating layer IL2 may have a stepped upper surface. That is, in the insulating layer IL2, the portion relatively adjacent to the common connection pad CP2 may have a smaller height than the portion relatively far from the common connection pad CP2. However, this disclosure is not limited thereto. The insulating layer IL2 may have a sloping upper surface. In this case, the insulating layer IL2 may have a sloping upper surface whose height gradually increases with the distance from the common connection pad CP2.

[0228] In a display device 900 according to another exemplary embodiment of the present disclosure, an insulating layer IL2 is provided on a first connection line 181 serving as a high-potential power line. Therefore, misalignment of the LED 160 can be minimized. Specifically, if the LED 160 moves toward the first connection line 181 for transmitting high-potential power due to movement of the adhesive layer AD, the portion of the insulating layer IL2 relatively adjacent to the common connection pad CP2 can initially suppress the movement of the LED 160. Furthermore, if the LED 160 moves to a portion of the insulating layer IL2 relatively adjacent to the common connection pad CP2, the portion of the insulating layer IL2 relatively far from the common connection pad CP2 and having a higher height can secondarily suppress the movement of the LED 160. Therefore, in the display device 900 according to another exemplary embodiment of the present disclosure, misalignment of the LED 160 caused by movement of the adhesive layer AD can be suppressed.

[0229] Furthermore, in a display device 900 according to another exemplary embodiment of this disclosure, an insulating layer IL2 is provided on a first connection line 181 serving as a high-potential power line. Therefore, even if the plurality of LEDs 160 are misaligned, connection between the LEDs 160 and the first connection line 181 serving as a power line for transmitting high-potential power can be suppressed. That is, even if the LEDs 160 are positioned on the first connection line 181 serving as a power line for transmitting high-potential power due to movement of the adhesive layer AD, the LEDs 160 can still be prevented from connecting to the first connection line 181 serving as a power line for transmitting high-potential power by means of the insulating layer IL2 provided on the first connection line 181. Therefore, the occurrence of dark spots caused by the LEDs 160 connecting to both the common connection pad CP2 and the first connection line 181 serving as a power line for transmitting high-potential power can be suppressed.

[0230] Figure 10 This is a schematic cross-sectional view of a pixel substrate of a display device according to yet another exemplary embodiment of the present disclosure. Apart from the insulating layer IL3, Figure 10 The display device 1000 shown and Figure 8 The display device 800 shown is essentially the same. Therefore, its redundant description will be omitted.

[0231] Reference Figure 10 According to another exemplary embodiment of the present disclosure, the display device 1000 may include an insulating layer IL3. The insulating layer IL3 may be disposed on the first connection line 181. Specifically, the insulating layer IL3 may be disposed on the power line PL in the first connection line 181 for transmitting high-potential power.

[0232] The insulating layer IL3 can be configured to cover the upper and side surfaces of the first connection line 181, which serves as a power line for transmitting high-potential power. Specifically, the insulating layer IL3 can be configured to cover the upper surface of the first connection line 181 and the side surface of the first connection line 181 adjacent to the common connection pad CP2. That is, the insulating layer IL3 can insulate the LED 160 from the upper and side surfaces of the first connection line 181, which serves as a power line for transmitting high-potential power.

[0233] In a display device 1000 according to another exemplary embodiment of the present disclosure, an insulating layer IL3 is provided on the upper and side surfaces of a first connection line 181 serving as a high-potential power line. Therefore, misalignment of the LED 160 can be minimized. Specifically, if the LED 160 moves toward the first connection line 181 serving as a power line for transmitting high-potential power due to movement of the adhesive layer AD, the insulating layer IL3 can suppress the movement of the LED 160. Therefore, in the display device 1000 according to another exemplary embodiment of the present disclosure, misalignment of the LED 160 caused by movement of the adhesive layer AD can be suppressed.

[0234] Furthermore, in a display device 1000 according to another exemplary embodiment of the present disclosure, an insulating layer IL3 is provided on the upper surface and side surface of the first connection line 181, which serves as a high-potential power line. Therefore, even if the plurality of LEDs 160 are misaligned, connection between the LEDs 160 and the first connection line 181, which serves as a power line for transmitting high-potential power, can be suppressed. That is, even if the LEDs 160 move toward the first connection line 181, which serves as a power line for transmitting high-potential power, due to the movement of the adhesive layer AD, the LEDs 160 can remain unconnected to the first connection line 181, which serves as a power line for transmitting high-potential power, thanks to the insulating layer IL3 provided on the upper surface of the first connection line 181 and on the side surface of the first connection line 181 adjacent to the common connection pad CP2. Therefore, the occurrence of dark spots caused by the LEDs 160 connecting to both the common connection pad CP2 and the first connection line 181, which serves as a power line for transmitting high-potential power, can be suppressed.

[0235] Figure 11 This is a schematic cross-sectional view illustrating the removal of the upper common connection pad via a repair process of a display device according to an exemplary embodiment of the present disclosure. In addition to removing the upper common connection pad CP22, Figure 11 The display device 1100 shown and Figures 1 to 4 The display device 100 shown is essentially the same. Therefore, its redundant description will be omitted.

[0236] Reference Figure 11 After the repair process, in accordance with Figures 1 to 4 In the display device 1100 of the display device 100 shown, the upper common connection pad CP22 of the common connection pad CP2 is removed together with the LED 160. Therefore, the common connection pad CP2 can have a single-layer structure.

[0237] In some sub-pixels of the multiple sub-pixels SPX of the display device 1100 after the repair process, the common connection pad CP2 can be as follows: Figure 11The single layer is shown. However, in other sub-pixel SPXs, only LED 160 was removed during the repair process, and the upper common connection pad CP22 was retained. Therefore, these sub-pixel SPXs can be in the following state: Figures 1 to 4 The state shown.

[0238] Furthermore, in some of the multiple sub-pixels SPX of the display device 1100 after the repair process, only a portion of the upper common connection pad CP22 can be removed along with the LED 160, while the other portions can be retained.

[0239] <Deformation of the adhesive layer>

[0240] Figure 12A This is an enlarged plan view of a pixel substrate of a display device according to another embodiment of the present disclosure. Figure 12B This is a schematic cross-sectional view of a pixel substrate of a display device according to another embodiment of the present disclosure. Except that the upper common connection pad CP22 is removed and the adhesive layer AD is provided differently, Figure 12A and Figure 12B The display device 1200 shown and Figures 1 to 4 The display device 100 shown is essentially the same. Therefore, its redundant description will be omitted.

[0241] Reference Figure 12A and Figure 12B The adhesive layer AD is used to electrically connect multiple independent connection pads CP1 and a common connection pad CP2 to multiple LEDs 160.

[0242] The adhesive layer AD is configured to cover the entire upper surface of the planarization layer 115. The adhesive layer AD is disposed on the entire upper surface of the planarization layer 115 and on the upper surfaces of the individual connection pads CP1 and the common connection pad CP2. Therefore, the LED 160 can be bonded to the individual connection pads CP1 and the common connection pad CP2. Here, the n-electrode 165 can be disposed on the common connection pad CP2, and the p-electrode 164 can be disposed on the individual connection pad CP1.

[0243] The adhesive layer AD comprises multiple conductive balls CB and a base component BR. The adhesive layer AD can be a conductive adhesive layer formed by dispersing multiple conductive balls CB within the base component BR. When the electrodes of LED 160 are bonded to the common connection pad CP2 and the independent connection pad CP1, the multiple conductive balls CB dispersed in the base component BR can be used to electrically connect the electrodes of LED 160 to the common connection pad CP2 and the independent connection pad CP1.

[0244] In some implementations, multiple conductive balls CB are disposed in a single layer. For example... Figure 13AAs shown, conductive spheres CB are dispersed within the base component BR. The conductive spheres CB are separated from each other at predetermined distances within a single layer. For example, the distance between conductive spheres CB can be from 2 μm to 3 μm, but is not limited to this. In this document, the distance between conductive spheres CB refers to the shortest distance between one conductive sphere CB and another.

[0245] Because the multiple conductive balls CB are separated from each other, they are not electrically connected to each other. That is, the multiple conductive balls CB are parallel to and separated from each other by the upper surface of the planarization layer 115, and therefore are not electrically connected to each other. Furthermore, the multiple conductive balls CB electrically connect multiple individual connection pads CP1 and a common connection pad CP2 to multiple LEDs 160. In other words, the multiple conductive balls CB contact the connection pads and the electrodes of the LEDs 160 in a direction perpendicular to the upper surface of the planarization layer 115. Therefore, the multiple conductive balls CB can electrically connect the electrodes of the LEDs 160 to the connection pads.

[0246] The base component BR can be an adhesive component with adhesive and insulating properties. Except for the portion where the conductive balls CB are located, the adhesive layer AD has insulating properties. The base component BR is coated on the entire upper surface of the planarization layer 115, allowing the positions of the multiple LEDs 160 to be fixed.

[0247] The thickness or height H1 of the adhesive layer AD is less than the thickness or height H2 of the planarization layer 115 (see example). Figure 13A If the thickness of the adhesive layer AD is greater than the thickness of the planarization layer 115, the adhesive layer AD can flow downwards to the outside of the upper surface of the planarization layer 115. Therefore, the LED 160 may become misaligned. That is, the movement of the adhesive layer AD can be constrained by a step between the thicknesses of the planarization layer 115 and the adhesive layer AD. Furthermore, the adhesive layer AD can be disposed on the entire upper surface of the planarization layer 115 such that the edge of the upper surface of the planarization layer 115 coincides with the edge of the adhesive layer AD. Simultaneously, the side surfaces of the adhesive layer AD can be perpendicular to or inclined to the upper surface of the planarization layer 115, but are not limited to these limitations.

[0248] In a display device 1200 according to another embodiment of the present disclosure, a plurality of conductive balls CB included in the adhesive layer AD are separated from each other in a single layer. Therefore, the occurrence of short circuits or open circuits in the LEDs 160 can be suppressed. Furthermore, in the display device 1200 according to another embodiment of the present disclosure, the adhesive layer AD is disposed on the entire upper surface of the planarization layer 115, rather than selectively disposed on the connection pads overlapping with the plurality of LEDs 160. Therefore, the reduction in transfer efficiency of the LEDs 160 and driving defects of the LEDs 160 caused by uneven placement of the adhesive layer AD can be minimized.

[0249] In the following text, reference will be made to Figures 13A to 13D A method for manufacturing a display device 1200 according to yet another embodiment of the present disclosure is described.

[0250] Figures 13A to 13D This is a schematic cross-sectional view illustrating a method of manufacturing a display device according to yet another embodiment of the present disclosure. Figure 13D The display device shown is Figure 12A and Figure 12B The display device 1200 shown is basically the same. Therefore, its redundant description will be omitted.

[0251] First, refer to Figure 13A A first transfer substrate 191 is prepared, on which an adhesive layer AD is disposed. The adhesive layer AD includes a base component BR and a plurality of conductive balls CB dispersed in the base component BR.

[0252] Then, the first transfer substrate 191 is brought close to the upper part of the lower substrate 110. A planarization layer 115 is provided on the lower substrate 110, and the adhesive layer AD is placed on the upper part of the planarization layer 115. Here, the first transfer substrate 191 can be in the form of a film, but is not limited to this. When the first transfer substrate 191 and the lower substrate 110 are held in a flat state, the adhesive layer AD is pressed for a predetermined time period to bond to the planarization layer 115.

[0253] Then, refer to Figure 13B The first transfer substrate 191 is separated from the adhesive layer AD. Only the portion of the first transfer substrate 191 on which the planarization layer 115 is disposed is locally heated, so that the adhesive layer AD is bonded only to the planarization layer 115. For example, a heating rod is contacted with and pressed against the area corresponding to the planarization layer 115, so that only the adhesive layer AD bonded to the upper surface of the planarization layer 115 is separated from the first transfer substrate 191. However, this disclosure is not limited to this. Then, when the first transfer substrate 191 is removed, the adhesive layer AD is only disposed on the planarization layer 115.

[0254] Then, refer to Figure 13C A second transfer substrate 192, on which a plurality of LEDs 160 are disposed, is positioned close to the upper portion of the adhesive layer AD, and the plurality of LEDs 160 are bonded to the upper portion of the adhesive layer AD. For example, the plurality of LEDs 160 are transferred while they are bonded to the second transfer substrate 192 by adhesive members. The plurality of LEDs 160 disposed on the second transfer substrate 192 are bonded to the upper portion of the adhesive layer AD such that the plurality of LEDs 160 are positioned above the connection pads of the lower substrate 110. When the laser irradiates the plurality of LEDs 160, the adhesive members are removed, and the plurality of LEDs 160 separate from the second transfer substrate 192 and are fixed to the connection pads by the adhesive layer AD.

[0255] Then, refer to Figure 13D The upper substrate US can be formed by coating and hardening a flexible or stretchable insulating material onto multiple LEDs 160. Therefore, the upper substrate US can be configured to contact the lower substrate 110, the pixel substrate 111, the connecting member 120, and the connecting line 180. As a result, it is possible to manufacture... Figure 12A and Figure 12B The display device 1200 shown is shown.

[0256] Typically, when transferring adhesive layers, inkjet printing is used to selectively transfer the adhesive layer only to areas where the electrodes of the light-emitting diodes are located or to the bonding pads on the planarization layer. However, if the adhesive layer is transferred via inkjet printing, the transfer is limited due to the high viscosity of the adhesive layer. Furthermore, inkjet printing is a complex process and requires expensive equipment.

[0257] However, according to another embodiment of the present disclosure, the method for manufacturing the display device 1200 involves bonding the adhesive layer AD to the planarization layer 115, and then bonding the LED thereon. This simplifies the manufacturing process and reduces manufacturing time and cost. Specifically, instead of the adhesive layer being provided only on a portion of the planarization layer, the adhesive layer AD is provided over a larger area on the entire upper surface of the planarization layer 115. Therefore, the adhesive layer AD can be bonded more easily, and the LED 160 can be easily positioned using the adhesive layer AD. Furthermore, the adhesive layer AD is uniformly coated on the planarization layer 115. This improves the transfer efficiency of the LED 160, reduces manufacturing time, and minimizes driving defects in the LED 160.

[0258] Exemplary embodiments of this disclosure can also be described as follows:

[0259] According to one aspect of this disclosure, the display device may include a lower substrate and a plurality of pixel substrates disposed on the lower substrate. The display device also includes a plurality of transistors disposed on the plurality of pixel substrates and a planarization layer disposed on the plurality of pixel substrates to cover the upper portion of the plurality of transistors. The display device further includes a common connection pad and a plurality of individual connection pads disposed on the planarization layer. The display device also includes a plurality of light-emitting diodes disposed on the common connection pads and the plurality of individual connection pads. At least one of the plurality of individual connection pads and the common connection pad may have a multilayer structure.

[0260] The common connection pad may include a lower common connection pad disposed on the planarization layer and an upper common connection pad disposed on the lower common connection pad.

[0261] The upper common connection pad can be made of a material that has a higher adhesion to the electrodes of multiple light-emitting diodes than to the lower common connection pad.

[0262] The lower common connection pad can be made of copper (Cu), and the upper common connection pad can be made of gold (Au), titanium (Ti), aluminum (Al), or molybdenum (Mo).

[0263] The upper common connection pad can be set on the edge of the lower common connection pad.

[0264] The upper common connection pad can also correspond to the space between multiple independent connection pads, which is set on the lower common connection pad.

[0265] The upper common connection pads can be set in a grid pattern on the lower common connection pads.

[0266] Multiple independent connection pads may include lower independent connection pads disposed on the planarization layer and upper independent connection pads disposed on the lower independent connection pads. The upper independent connection pads may have a shape corresponding to the upper common connection pads and are disposed on the lower independent connection pads.

[0267] The display device may also include power lines disposed on the planarization layer and an insulating layer disposed on the power lines.

[0268] The insulating layer may include multiple insulating patterns disposed on the power line.

[0269] In the insulating layer, the portion relatively adjacent to the common connection pad can have a smaller height than the portion relatively far from the common connection pad.

[0270] The insulating layer can be configured to cover the side surface of the power line adjacent to the common connection pad.

[0271] The distance between the common connection pad and multiple individual connection pads can be greater than the distance between the common connection pad and the power line.

[0272] According to another aspect of this disclosure, the display device may include a plurality of pixel substrates disposed on a lower substrate and wherein a plurality of light-emitting diodes are disposed. The display device further includes a planarization layer covering the upper portion of the plurality of pixel substrates. The display device further includes a plurality of individual connection pads disposed on the planarization layer to correspond to the plurality of light-emitting diodes respectively. The display device further includes a common connection pad disposed on the planarization layer and electrically connected to all the plurality of light-emitting diodes. The display device further includes an adhesive layer electrically connecting the common connection pad and the plurality of individual connection pads to the plurality of light-emitting diodes. At least one of the plurality of individual connection pads and the common connection pad may have a lower pad and an upper pad disposed on the edge of the lower pad.

[0273] The upper pads can be made of a different material than the lower pads.

[0274] The upper pads can be set on the lower pads in a grid pattern.

[0275] The display device may further include: a high-potential power line disposed on the planarization layer; and an insulating layer disposed on the high-potential power line. A common connection pad may be disposed between multiple independent connection pads and the high-potential power line.

[0276] The insulating layer can be configured to cover the side surface of the high-potential power line.

[0277] According to another aspect of this disclosure, the display device includes a plurality of pixel substrates disposed on a lower substrate, and a plurality of light-emitting diodes (LEDs) disposed on the plurality of pixel substrates. The display device also includes a planarization layer covering the upper portion of the plurality of pixel substrates. The display device further includes a plurality of independent connection pads disposed on the planarization layer and corresponding to the plurality of LEDs respectively. The display device also includes a common connection pad disposed on the planarization layer and electrically connected to all the plurality of LEDs. The display device further includes an adhesive layer that electrically connects the plurality of independent connection pads and the common connection pad to the plurality of LEDs, and is configured to cover the entire upper surface of the planarization layer.

[0278] The adhesive layer may include multiple conductive spheres and a base component. The multiple conductive spheres may be disposed in a single layer while being dispersed within the base component.

[0279] Multiple conductive balls can be separated from each other and not electrically connected to each other, and multiple independent connection pads and a common connection pad can be electrically connected to multiple light-emitting diodes.

[0280] The thickness of the adhesive layer can be equal to or less than the thickness of the planarization layer.

[0281] According to another aspect of this disclosure, a method of manufacturing a display device may include the following process: placing an adhesive layer comprising a base component and a plurality of conductive balls dispersed in the base component on a first transfer substrate. The method of manufacturing a display device further includes the following process: bringing the first transfer substrate close to the upper portion of a substrate having a planarization layer covering the upper portion of a plurality of transistors, and bonding the adhesive layer to the upper portion of the planarization layer. The method of manufacturing a display device further includes the following process: bringing a second transfer substrate having a plurality of light-emitting diodes disposed thereon close to the upper portion of the adhesive layer, and bonding the plurality of light-emitting diodes to the upper portion of the adhesive layer.

[0282] Multiple conductive balls can be separated from each other and not electrically connected to each other, and multiple independent connection pads and a common connection pad can be electrically connected to multiple light-emitting diodes.

[0283] Although exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto and may be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments of the present disclosure are provided merely for illustrative purposes and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above exemplary embodiments are illustrative in all respects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the appended claims, and all technical concepts within the equivalent scope thereof should be interpreted as falling within the scope of the present disclosure.

[0284] Cross-references to related applications

[0285] This application claims priority to Korean Patent Application No. 10-2020-0153424, filed with the Korean Intellectual Property Office on November 17, 2020, and Korean Patent Application No. 10-2021-0139771, filed with the Korean Intellectual Property Office on October 19, 2021, the disclosures of which are incorporated herein by reference.

Claims

1. A display device, the display device comprising: Pixel substrate; A plurality of transistors, the plurality of transistors being disposed on the pixel substrate; A planarization layer is disposed on the pixel substrate to cover the upper part of the plurality of transistors; A common connection pad and a plurality of independent connection pads are disposed on the planarization layer; as well as Multiple light-emitting diodes are disposed on the common connection pad and the multiple individual connection pads. Wherein, at least one of the plurality of independent connection pads and the common connection pad has a multi-layer structure. The common connection pad includes a lower common connection pad disposed on the planarization layer and an upper common connection pad disposed on the lower common connection pad. The upper common connection pad is arranged on the edge of the lower common connection pad in the form of a closed curve or in the form of multiple patterns.

2. The display device according to claim 1, wherein, The upper common connection pad is made of a material that has a higher adhesion to the electrodes of the plurality of light-emitting diodes than to the lower common connection pad.

3. The display device according to claim 2, wherein, The lower common connection pad is made of copper (Cu), and The upper common connection pad is made of gold (Au), titanium (Ti), aluminum (Al), or molybdenum (Mo).

4. The display device according to claim 2, wherein, The material of the upper common connection pad is different from the material of the lower common connection pad, but the same as the material of the electrodes of the plurality of light-emitting diodes.

5. The display device according to claim 1, wherein, The upper common connection pad is also disposed on the lower common connection pad corresponding to the space between the plurality of independent connection pads.

6. The display device according to claim 5, wherein, The upper common connection pad is arranged in a grid pattern on the lower common connection pad.

7. The display device according to claim 1, wherein, The plurality of independent connection pads includes a lower independent connection pad disposed on the planarization layer and an upper independent connection pad disposed on the lower independent connection pad, and The upper independent connection pad has a shape corresponding to the upper common connection pad.

8. The display device according to claim 1, further comprising: A power cord, which is disposed on the planarization layer; as well as An insulating layer is disposed on the power line.

9. The display device according to claim 8, wherein, The insulating layer includes a plurality of insulating patterns disposed on the power line.

10. The display device according to claim 9, wherein, Each of the plurality of light-emitting diodes is bonded to a corresponding independent connection pad and a common connection pad of the plurality of independent connection pads via an adhesive layer, the adhesive layer being formed by dispersing conductive balls in a base component having adhesive and insulating properties. The distance between the plurality of insulating patterns is smaller than the size of the conductive ball.

11. The display device according to claim 8, wherein, In the insulating layer, the portion relatively adjacent to the common connection pad has a smaller height than the portion relatively far from the common connection pad.

12. The display device according to claim 8, wherein, The insulating layer is configured to cover the side surface of the power line adjacent to the common connection pad.

13. The display device according to claim 8, wherein, The distance between the common connection pad and the plurality of independent connection pads is greater than the distance between the common connection pad and the power line.

14. The display device according to claim 8, wherein, The power line is configured to transmit high-potential power and is positioned adjacent to and insulated from the common connection pad.

15. The display device according to claim 1, wherein, Each of the plurality of light-emitting diodes is disposed on a corresponding independent connection pad among the plurality of independent connection pads, and all of the plurality of light-emitting diodes are disposed on the common connection pad.

16. The display device according to claim 1, wherein, The independent connection pad is electrically connected to the first electrode of the light-emitting diode, and the common connection pad is connected to the second electrode of the light-emitting diode.

17. A display device, the display device comprising: A pixel substrate, wherein a plurality of light-emitting diodes are disposed in the pixel substrate; A planarization layer covering the upper part of the pixel substrate; Multiple independent connection pads are disposed on the planarization layer to correspond to the multiple light-emitting diodes respectively; A common connection pad is disposed on the planarization layer and electrically connected to all of the plurality of light-emitting diodes; as well as An adhesive layer electrically connects the common connection pad and the plurality of individual connection pads to the plurality of light-emitting diodes. Wherein, at least one of the plurality of independent connection pads and the common connection pad has a lower pad and an upper pad disposed on the lower pad. The upper pad is arranged on the edge of the lower pad in the form of a closed curve or in the form of multiple patterns.

18. The display device according to claim 17, wherein, The upper pad is made of a different material than the lower pad.

19. The display device according to claim 17, wherein, The upper pads are arranged in a grid pattern on the lower pads.

20. The display device according to claim 17, further comprising: A high-potential power line is disposed on the planarization layer; as well as An insulating layer is disposed on the high-potential power line. The common connection pad is disposed between the plurality of independent connection pads and the high-potential power line.

21. The display device according to claim 20, wherein, The insulating layer is configured to cover the side surface of the high-potential power line.

22. A display device, the display device comprising: Multiple pixel substrates are disposed on a lower substrate, and multiple light-emitting diodes are disposed on the multiple pixel substrates; A planarization layer covering the upper part of the plurality of pixel substrates; Multiple independent connection pads are disposed on the planarization layer and each corresponds to one of the multiple light-emitting diodes; A common connection pad is disposed on the planarization layer and electrically connected to all of the plurality of light-emitting diodes; as well as An adhesive layer electrically connects the plurality of individual connection pads and the common connection pad to the plurality of light-emitting diodes, and the adhesive layer is configured to cover the entire upper surface of the planarization layer. Wherein, at least one of the plurality of independent connection pads and the common connection pad has a lower pad and an upper pad disposed on the lower pad. The upper pad is arranged on the edge of the lower pad in the form of a closed curve or in the form of multiple patterns.

23. The display device according to claim 22, wherein, The adhesive layer includes multiple conductive balls and a base component, and The plurality of conductive balls are disposed in a single layer while being dispersed in the base component.

24. The display device according to claim 23, wherein, The plurality of conductive balls are spaced apart from each other and are not electrically connected to each other, and the plurality of conductive balls electrically connect the plurality of independent connection pads and the common connection pad to the plurality of light-emitting diodes.

25. The display device according to claim 23, wherein, The plurality of conductive balls are parallel to and spaced apart from each other from the upper surface of the planarization layer, and the plurality of conductive balls are in contact with the electrodes of the plurality of light-emitting diodes, the plurality of individual connection pads and the common connection pad in a direction perpendicular to the upper surface of the planarization layer.

26. The display device according to claim 23, wherein, The thickness of the adhesive layer is equal to or less than the thickness of the planarization layer.

27. A method for manufacturing a display device, the method comprising the following steps: An adhesive layer comprising a base component and a plurality of conductive balls dispersed in the base component is placed on a first transfer substrate; The first transfer substrate is brought close to the upper part of the lower substrate on which the planarization layer covering the upper part of a plurality of transistors is disposed, and the adhesive layer is bonded to the upper part of the planarization layer. Separate the first transfer substrate from the adhesive layer bonded to the upper part of the planarization layer; as well as The second transfer substrate, on which multiple light-emitting diodes are disposed, is brought close to the upper part of the adhesive layer, and the multiple light-emitting diodes are bonded to the upper part of the adhesive layer. The display device includes multiple independent connection pads and a common connection pad disposed on the planarization layer. Wherein, at least one of the plurality of independent connection pads and the common connection pad has a lower pad and an upper pad disposed on the lower pad. The upper pad is arranged on the edge of the lower pad in the form of a closed curve or in the form of multiple patterns.

28. The method of manufacturing a display device according to claim 27, wherein, The plurality of conductive balls are separated from each other and are not electrically connected to each other, and the plurality of conductive balls electrically connect the plurality of independent connection pads and the common connection pad to the plurality of light-emitting diodes.

29. The method of manufacturing a display device according to claim 28, wherein, The plurality of conductive spheres are arranged in a single layer.

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