Display device and manufacturing method thereof

Abstract

The present invention relates to a display device manufacturing method and a display device according to the same, the method comprising the steps of: placing a plurality of light emitting elements on a first transfer film; stretching the first transfer film such that the plurality of light emitting elements are spaced apart from each other; transferring a plurality of light emitting elements onto the TFT array substrate; and removing the transfer film from the plurality of light emitting elements.

Description

[0001] This application is a divisional application of an invention patent application with an application date of December 13, 2018, application number "201880098735.9" and invention name "Display device and manufacturing method thereof". Technical Field

[0002] Various embodiments of the present disclosure are directed to a display device and a method of manufacturing the display device. Background Art

[0003] The display device uses a combination of light emitted from multiple pixels to display an image. In the display device, each pixel includes a pixel circuit and a display element controlled by the pixel circuit in operation. A light emitting diode as a self-emitting element among the display elements includes a pixel electrode, an emission layer and a common electrode.

[0004] One of the pixel electrode and the common electrode is an anode for hole injection, and the other is a cathode for electron injection. The holes injected from the anode and the electrons injected from the cathode are combined in the emission layer to generate excitons, and the excitons release energy to emit light.

[0005] The LEDs can be formed on the backplane by a pick and place method or a roll transfer method. However, these conventional methods require precise alignment between the pixel area and the LEDs during the transfer process and require a separate process for bonding the LEDs, resulting in high complexity and long process times. Summary of the invention

[0006] Technical issues Various embodiments of the present disclosure relate to a display device in which a light emitting diode is formed on a TFT array substrate using a stretchable transfer film and a method of manufacturing the display device.

[0007] Technical Solution According to one aspect of the present disclosure, a method for manufacturing a display device may include the following steps: arranging a plurality of light-emitting elements on a first transfer film; stretching the first transfer film so that the plurality of light-emitting elements are spaced apart from each other; transferring the plurality of light-emitting elements onto a TFT array substrate; and removing the first transfer film from the plurality of light-emitting elements.

[0008] The first transfer film may be formed of a stretchable material.

[0009] The first transfer film may be formed of a material including at least one of polyolefin, polyvinyl chloride (PVC), elastomeric silicone, elastomeric polyurethane, and elastomeric polyisoprene.

[0010] The first transfer film may be stretched so that the plurality of light emitting elements may have a desired density corresponding to the pixel area of ​​the TFT array substrate.

[0011] The first transfer film may be two-dimensionally stretched in a plurality of directions including a first direction and a second direction perpendicular to the first direction.

[0012] The method may further include: transferring the plurality of light emitting elements disposed on the first transfer film to a second transfer film after stretching the first transfer film; and stretching the second transfer film so that the plurality of light emitting elements are further spaced apart from each other.

[0013] The step of transferring the plurality of light emitting elements onto the TFT array substrate may include irradiating infrared laser onto a rear surface of the first transfer film facing the plurality of light emitting elements.

[0014] The step of removing the first transfer film may include radiating ultraviolet laser or heat onto the first transfer film.

[0015] At least one light emitting element that is not transferred to the pixel region of the TFT array substrate may be removed together with the first transfer film.

[0016] The TFT array substrate may include a substrate, a transistor on the substrate, a planarization layer on the transistor, and a first electrode on the planarization layer, and the light emitting element may be transferred onto the first electrode.

[0017] The first electrode may be completely formed on the pixel region of the TFT array substrate.

[0018] The first electrode may be electrically coupled to the transistor through a via formed in the planarization layer.

[0019] Each light emitting element may include a first semiconductor layer, a second semiconductor layer, and an intermediate layer between the first semiconductor layer and the second semiconductor layer, and the light emitting element may be transferred so that the first semiconductor layer contacts the first electrode.

[0020] The method may further include: forming a capping layer on the planarization layer to which the plurality of light emitting elements are transferred; etching the capping layer so that first ends of the plurality of light emitting elements are exposed; and forming a second electrode on the etched capping layer.

[0021] The second electrode may be formed entirely on the etched capping layer.

[0022] According to one aspect of the present disclosure, a display device may include: a substrate including multiple pixel areas; a first electrode arranged on each pixel area; multiple light-emitting elements arranged on the first electrode; and a second electrode arranged on the multiple light-emitting elements, wherein the multiple light-emitting elements may be randomly arranged on the first electrode.

[0023] Each of the light emitting elements may include a first semiconductor layer, a second semiconductor layer, and an intermediate layer between the first semiconductor layer and the second semiconductor layer, and the first semiconductor layer may contact the first electrode.

[0024] The display device may further include a cover layer configured to surround the plurality of light emitting elements.

[0025] The second electrode may be formed entirely on the capping layer.

[0026] The first electrode may be an anode electrode, and the second electrode may be a cathode electrode.

[0027] Beneficial Effects The display device and the method of manufacturing the display device according to the embodiments of the present disclosure do not require separate alignment when forming light emitting diodes on a backplane, and allow a plurality of light emitting elements to be joined in a single process, thereby reducing process defect rates and shortening process time.

[0028] Furthermore, since a contact electrode of a light emitting diode may be exposed to the outside without an additional process, the display device and the method of manufacturing the same according to the embodiment of the present disclosure may be applied to a small light emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a diagram showing a structure of a light emitting element according to an embodiment of the present disclosure.

[0030] Figures 2 to 11 is a cross-sectional view of a process of manufacturing a transfer film according to an embodiment of the present disclosure.

[0031] Figures 12 to 18 is a cross-sectional view of a process of manufacturing a display device according to an embodiment of the present disclosure.

[0032] Fig.19 is a plan view schematically showing a display device according to an embodiment of the present disclosure.

[0033] Fig. 20 It is schematically shown Fig.19 A cross-sectional view of an example of a cross-section of a display device. DETAILED DESCRIPTION

[0034] Since the present disclosure allows various changes and many embodiments, specific embodiments will be shown in the drawings and described in detail in the written description. However, this is not intended to limit the present disclosure to a specific mode of practice, and it will be understood that all changes, equivalents and substitutes that do not depart from the spirit and technical scope of the present disclosure are included in the present disclosure.

[0035] Throughout the disclosure, throughout the various figures and embodiments of the present disclosure, the same reference numerals represent the same parts. For clarity, the size of the elements in the drawings may be exaggerated. It will be understood that, although the terms "first", "second", etc. may be used to describe various elements here, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the teachings of the present disclosure, the first element discussed below may be named as the second element. Similarly, the second element may also be named as the first element. In the present disclosure, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form.

[0036] It will also be understood that when the terms "comprise", "include", "have", etc. are used in this specification, it indicates the presence of the stated features, wholes, steps, operations, elements, components and / or combinations thereof, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof. In addition, when a first component such as a layer, film, region or plate is disposed on a second component, the first component may not only be directly located on the second component, but a third component may be placed between them. In addition, when it is indicated that a first component such as a layer, film, region or plate is formed on a second component, the surface of the second component on which the first component is formed is not limited to the upper surface of the second component, but may include other surfaces such as the side surface or lower surface of the second component. Conversely, when a first component such as a layer, film, region or plate is located below a second component, the first component may not only be directly located below the second component, but a third component may be placed between them.

[0037] Hereinafter, a display device and a method of manufacturing the same according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0038] Figure 1 is a diagram showing a structure of a light emitting element according to an embodiment of the present disclosure.

[0039] Reference Figure 1 , the light emitting element 120 according to an embodiment of the present disclosure may be a vertical light emitting element formed by sequentially stacking a first semiconductor layer 121 , an intermediate layer 122 , and a second semiconductor layer 123 .

[0040] For example, the first semiconductor layer 121 may be implemented as a p-type semiconductor layer. The p-type semiconductor layer may be selected from a material having In x Al y Ga 1-x-yA semiconductor material having a composition formula of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN, and may be doped with a p-type dopant such as Mg, Zn, Ca, Sr, or Ba.

[0041] For example, the second semiconductor layer 123 may be formed to include an n-type semiconductor layer. The n-type semiconductor layer may be selected from a group consisting of In x Al y Ga 1-x-y A semiconductor material having a composition formula of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN, and may be doped with an n-type dopant such as Si, Ge, or Sn.

[0042] However, the present disclosure is not limited thereto. In other words, the first semiconductor layer 121 may include an n-type semiconductor layer, and the second semiconductor layer 123 may include a p-type semiconductor layer.

[0043] The intermediate layer 122 is a region where electrons and holes are recombined. When the electrons and holes are recombined, the intermediate layer 122 may be transferred to a low energy level and generate light having a wavelength corresponding thereto. For example, the intermediate layer 122 may be formed to include a x Al y Ga 1-x-y The intermediate layer 122 may be formed into a single quantum well structure or a multi-quantum well (MQW) structure. In addition, a quantum wire structure or a quantum dot structure may be included.

[0044] although Figure 1 An example in which the intermediate layer 122 is formed as a single quantum well structure is shown, but in another embodiment, the intermediate layer 122 may be formed as a multi-quantum well (MQW) structure. In this embodiment, the intermediate layer 122 may be a multilayer structure formed by alternately stacking active layers and insulating layers. In this embodiment, the active layer and the insulating layer may be formed to have the same thickness or to have different thicknesses (asymmetric quantum well (AQW)).

[0045] In an embodiment, the light emitting element 120 may further include an electrode layer (not shown) formed on the second semiconductor layer 123. In addition, the electrode layer may include a metal or a metal oxide. For example, chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), nickel (Ni), ITO (indium tin oxide), and oxides or alloys thereof may be used alone or in combination with each other. However, the present disclosure is not limited thereto.

[0046] In addition, in the embodiment, the light emitting element 120 may further include an insulating film (not shown). Figure 1 Such an insulating film is omitted in the figure. The insulating film may be provided to surround at least a portion of the outer peripheral surface of each of the first semiconductor layer 121, the intermediate layer 122, and the second semiconductor layer 123. For example, the insulating film may be provided on a portion of the light emitting element 120 other than the opposite ends thereof, so that the opposite ends of the light emitting element 120 may be exposed. The insulating film may include a transparent insulating material. For example, the insulating film may include a layer made of SiO 2 、Si 3 N 4 、Al 2 O 3 and TiO 2 At least one insulating material selected from the group consisting of, but not limited to, In other words, various materials having insulating properties can be used.

[0047] Figures 2 to 11 is a cross-sectional view of a process of manufacturing a transfer film according to an embodiment of the present disclosure.

[0048] First, refer to Figure 2 A plurality of light emitting elements 120 are disposed on a base substrate 110. The base substrate 110 may be made of a conductive substrate or an insulating substrate and may be made of, for example, sapphire (Al 2 O 3 ), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge and Ga 2 O 3 At least one of the formations.

[0049] The plurality of light emitting elements 120 may emit any one of blue light, red light and green light. Alternatively, some of the plurality of light emitting elements 120 may emit blue light, some of the plurality of light emitting elements 120 may emit red light, and some of the plurality of light emitting elements 120 may emit green light.

[0050] In addition, the first transfer film 210 is disposed to be spaced apart from the base substrate 110 .

[0051] The first transfer film 210 may be made of a stretchable material, and examples of the stretchable material may include polyolefin, polyvinyl chloride (PVC), elastomeric silicone, elastomeric polyurethane, elastomeric polyisoprene, etc., but are not limited thereto.

[0052] The first transfer film 210 may include a support layer 211 and an adhesive layer 212 disposed on the support layer 211 .

[0053] The support layer 211 is transparent to allow light emitted from the light source to be transmitted, and may be made of a material having appropriate optical properties and sufficient mechanical stability. For example, the support layer 211 may be a glass substrate, a quartz substrate, or a synthetic resin substrate made of a transparent polymer material having excellent light transmittance (such as polyester, polyacrylate, polyepoxy, polyethylene, polystyrene, or polyethylene terephthalate).

[0054] The light source may be an infrared laser beam. The light source is disposed below another surface of the support layer 211 (see Fig.13 ). The laser beam may scan the entire other surface of the support layer 211, or may be selectively irradiated to only a specific area.

[0055] The adhesive layer 212 may be formed of a transfer material, for example, an adhesive material for bonding the light emitting element 120. For example, the adhesive layer 212 may include polyurethane acrylate, epoxy acrylate, polyester acrylate, etc. In an embodiment, the adhesive material forming the adhesive layer 212 may be a material whose adhesive strength changes with application of ultraviolet (UV) light or heat, so that the adhesive layer 212 may be easily separated from the transfer material.

[0056] Reference Figure 3 Since the base substrate 110 and the first transfer film 210 are disposed adjacent to each other, the plurality of light emitting elements 120 formed on the base substrate 110 are bonded to the adhesive layer 212 of the first transfer film 210 .

[0057] Reference Figure 4 , the base substrate 110 is separated from the plurality of light emitting elements 120. Although the base substrate 110 and the plurality of light emitting elements 120 may be separated by a process such as laser lift off (LLO) or chemical lift off (CLO), the method of separating the base substrate 110 is not limited thereto.

[0058] The plurality of light emitting elements 120 separated from the base substrate 110 are temporarily fixed on the adhesive layer 212. Here, the plurality of light emitting elements 120 may be disposed at a first distance D1.

[0059] Reference Figure 5 and Figure 6, stretching the first transfer film 210. For example, the first transfer film 210 may be stretched two-dimensionally in a plurality of directions including a first direction and a second direction perpendicular to the first direction. When the first transfer film 210 is stretched, as shown in FIG. Figure 6 As shown in , the first distance D1 between the plurality of light emitting elements 120 fixed on the first transfer film 210 can be uniformly increased to the second distance D2. In this case, the first transfer film 210 can be stretched to have a density corresponding to a pixel (or sub-pixel) region in which a plurality of light emitting elements 120 are formed on a TFT array substrate to be described later. For example, the first transfer film 210 can be stretched so that N light emitting elements 120 are included in a region corresponding to a pixel formed on the TFT array substrate.

[0060] In various embodiments of the present disclosure, the transfer and stretching operations may be repeatedly performed to obtain the first transfer film 210 on which the light emitting elements 120 of a desired density are disposed. More specifically, referring to Figure 7 The second transfer film 210' can be set to Figure 4 Here, the second transfer film 210' may be separated from the first transfer film 210 manufactured in Figures 2 to 6 The second transfer film 210 ′ is the same as the first transfer film 210 shown in FIG.

[0061] Reference Figure 8 When the second transfer film 210 ′ and the first transfer film 210 are disposed adjacent to each other, the plurality of light emitting elements 120 formed on the first transfer film 210 are bonded to the adhesive layer 212 ′ of the second transfer film 210 ′.

[0062] Reference Fig. 9 , the first transfer film 210 is separated from the plurality of light emitting elements 120. Fig.10 , stretching the second transfer film 210'. If the second transfer film 210' is stretched, the distance between the light emitting elements 120 increases, and the density of the light emitting elements 120 decreases. By repeating this process, the density of the light emitting elements 120 is reduced, and a plurality of light emitting elements 120 having a desired density can be formed on the transfer film without damaging the transfer film due to an excessive stretching operation.

[0063] Hereinafter, a method of manufacturing a display device according to the present disclosure using the transfer film 210 ′ manufactured through the above-mentioned process will be described in detail.

[0064] Figures 12 to 18 is a cross-sectional view of a process for manufacturing a display device according to an embodiment of the present disclosure. Figures 12 to 18, a TFT array substrate 300 is schematically shown to easily describe a method of transferring the light emitting element 120 using a transfer film 210 ′.

[0065] First, refer to Fig.12 , the TFT array substrate 300 and the Figures 1 to 11 The transfer film 210 ′ formed with the plurality of light emitting elements 120 is disposed to be spaced apart from each other.

[0066] At least one thin film transistor for driving the plurality of light emitting elements 120 may be formed on the TFT array substrate 300 , and an insulating layer, a planarization layer, etc. may be formed.

[0067] In various embodiments of the present disclosure, a first electrode 311 may be formed on a planarization layer of a TFT array substrate 300. The first electrode 311 may be formed entirely on a pixel (or sub-pixel) region PA. In other words, the pixel (or sub-pixel) region PA may be defined by the first electrode 311.

[0068] The first electrode 311 may include a reflective layer formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a mixture thereof and a transparent or semi-transparent electrode formed on the reflective layer. The transparent or semi-transparent electrode may include a reflective layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In 2 O 3 ), at least one or more materials selected from the group consisting of indium gallium oxide (IGO) and aluminum zinc oxide (AZO).

[0069] The first electrode 311 may be electrically coupled to at least one thin film transistor formed on the TFT array substrate 300. Fig.19 The detailed structure of the TFT array substrate 300 is described in detail.

[0070] The transfer film 210' is disposed so that the plurality of light emitting elements 120 face the first electrode 311 on the TFT array substrate 300. The plurality of light emitting elements 120 disposed at a desired density are included on the adhesive layer 212' of the transfer film 210'.

[0071] Reference Fig.13 , the transfer film 210' is disposed adjacent to the TFT array substrate 300. When the transfer film 210' is disposed adjacent to the TFT array substrate 300, the plurality of light emitting elements 120 formed on the transfer film 210' are in contact with the first electrode 311 of the TFT array substrate 300. Fig.13As shown in FIG. 1 , if infrared laser IR is radiated onto the rear surface of the transfer film 210 ′, the plurality of light emitting elements 120 on the transfer film 210 ′ are transferred to the first electrode 311 on the TFT array substrate 300 .

[0072] In this case, the plurality of light emitting elements 120 are not transferred to the non-pixel area NPA (see Fig. 20 ).

[0073] Reference Fig.14 , the transfer film 210' is separated from the plurality of light emitting elements 120. In an embodiment, when the adhesive force between the plurality of light emitting elements 120 and the transfer film 210' is less than the adhesive force between the plurality of light emitting elements 120 and the first electrode 311, the transfer film 210' may be physically separated from the plurality of light emitting elements 120. Alternatively, in an embodiment, after weakening the adhesive strength of the adhesive layer 212' by radiating ultraviolet laser or heat on the rear surface of the transfer film 210', the transfer film 210' may be separated from the plurality of light emitting elements 120.

[0074] In this case, the light emitting element 120 that is not transferred onto the first electrode 311 may be removed from the TFT array substrate 300 together with the transfer film 210 ′.

[0075] Reference Fig.15 and Fig.16 , a second semiconductor layer 123 (see FIG. 1 ) that is aligned with the light emitting element 120 may be formed on the TFT array substrate 300 to which the plurality of light emitting elements 120 are transferred. Figure 1 ) contacts the second electrode 312 (see Fig.17 ).

[0076] More specifically, if Fig.15 As shown in FIG. 1 , a capping layer 306 may be formed on the TFT array substrate 300 to which the plurality of light emitting elements 120 are transferred. An inorganic insulating layer and / or an organic insulating layer may be used for the capping layer 306. The inorganic insulating layer may include SiO 2 、SiN x 、SiON、Al 2 O 3 、TiO 2 、 2 O 5 , HfO 2 、ZrO 2, BST, PZT, etc. The organic insulating layer may include common commercial polymers (PMMA, PS), polymer derivatives with phenol groups, acrylic polymers, imide polymers, aryl ether polymers, amide polymers, fluoropolymers, paraxylene polymers, vinyl alcohol polymers, and blends thereof. Optionally, in an embodiment, the capping layer 306 may also be formed by a composite stack of an inorganic insulating layer and an organic insulating layer.

[0077] The capping layer 306 is a layer for preventing oxygen and moisture from penetrating into the light emitting element 120, and may be a planarization layer in which steps are prevented from being formed on the upper surface. In order to improve the planarization characteristics of the capping layer 306, the capping layer 306 may preferably be formed of an organic insulating layer or a composite stack. However, the embodiments of the present disclosure are not limited thereto, and the capping layer 306 of various materials as described above may be used.

[0078] The cladding layer 306 may be formed to be higher than the plurality of light emitting elements 120 .

[0079] Reference Fig.16 The capping layer 306 is etched to expose the first ends of the plurality of light emitting elements 120. The capping layer 306 may be etched by a process such as dry etching, so that at least a portion of the second semiconductor layer 123 of the light emitting element 120 is exposed.

[0080] Reference Fig.17 , a second electrode 312 is formed on the capping layer 306 exposing a portion of the second semiconductor layer 123. The second electrode 312 may be formed entirely on the capping layer 306. The second electrode 312 may be a transparent or semi-transparent electrode and may be formed of a metal thin film having a low work function and including Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, or a mixture thereof. In addition, a metal such as ITO, IZO, ZnO, or In 2 O 3 The material for forming a transparent electrode further forms an auxiliary electrode layer or a bus electrode on the metal film. Therefore, the second electrode 312 can transmit light emitted from the light emitting element 120.

[0081] In addition, in the embodiment of the present disclosure, although the display device has been described as a top emission device in which the first electrode 311 reflects light and the second electrode 312 transmits light, the present disclosure may not be limited thereto. For example, in another embodiment of the present disclosure, the display device may be a bottom emission device.

[0082] Through the above process, a structure in which the first electrode 311 , the first semiconductor layer 121 , the intermediate layer 122 , the second semiconductor layer 123 , and the second electrode 312 are sequentially stacked is formed.

[0083] In various embodiments, the Fig.18 The subsequent processes shown in FIG. 3 further form various passivation layers and / or insulating layers (Encap) on the second electrode 312 .

[0084] According to the present disclosure, when a plurality of light emitting elements 120 are disposed on a TFT array substrate 300, precise alignment is not required, and the plurality of light emitting elements 120 are not transferred to the TFT array substrate 300 individually, but are transferred to the TFT array substrate all at once, so that the manufacturing efficiency of the display device can be improved and the defect rate can be reduced.

[0085] Furthermore, according to the present disclosure, since a separate mask process is not required to form the second electrode 312 , it is easy to manufacture a display device including the small light emitting element 120 .

[0086] Fig.19 is a plan view schematically showing a display device according to an embodiment of the present disclosure, Fig. 20 It is schematically shown Fig.19 A cross-sectional view of an example of a cross-section of a display device.

[0087] Reference Fig.19 and Fig. 20 , the display device 10 according to an embodiment of the present disclosure may include a TFT array substrate 300 and an emission layer 310 disposed on the TFT array substrate 300 .

[0088] The TFT array substrate 300 may include a substrate 301, a thin film transistor (active layer 307, gate electrode 308, source electrode 309a and drain electrode 309b) on the substrate 301, and a planarization layer 305 on the thin film transistor. A first electrode 311 coupled to the thin film transistor through a via hole may be formed on the planarization layer 305.

[0089] A display area DA and a non-display area NDA outside the display area DA may be defined on the substrate 301. A power line or the like may be disposed in the non-display area NDA. In addition, a pad (or "pad") assembly 350 may be disposed in the non-display area NDA.

[0090] The substrate 301 may include various materials. For example, the substrate 301 may include SiO 2The substrate 301 is made of a transparent glass material as a main component. However, the substrate 301 is not necessarily limited thereto and may be formed of a transparent plastic material to have flexibility. The plastic material may be an organic material selected from the group consisting of insulating organic materials such as polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallyl (compound), polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP).

[0091] In the case of a bottom emission type in which an image is formed in the direction of the substrate 301, the substrate 301 should be formed of a transparent material. However, in the case of a top emission type in which an image is formed in the direction opposite to the substrate 301, the substrate 301 is not necessarily formed of a transparent material. In this case, the substrate 301 may be formed of a metal.

[0092] When the substrate 301 is formed of a metal, the substrate 301 includes one or more metals selected from the group consisting of iron, chromium, manganese, nickel, titanium, molybdenum, stainless steel (SUS), Invar, Inconel, and Kovar, but the present disclosure is not limited thereto.

[0093] The buffer layer 302 may be formed on the substrate 301. The buffer layer 302 may provide a flat surface on the upper portion of the substrate 301, and may prevent foreign matter or moisture from penetrating the substrate 301. For example, the buffer layer 302 may include an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, or titanium nitride, or an organic material such as polyimide, polyester, or acrylic. It may be formed of a plurality of stacks among the exemplary materials.

[0094] The thin film transistor may include an active layer 307 , a gate electrode 308 , a source electrode 309 a , and a drain electrode 309 b .

[0095] Hereinafter, a case where a thin film transistor is a top gate type in which an active layer 307, a gate electrode 308, a source electrode 309a, and a drain electrode 309b are sequentially formed will be described. However, the technical concept of the present disclosure is not limited thereto, and various types of thin film transistors such as a bottom gate type may be employed.

[0096] The active layer 307 may include a semiconductor material such as amorphous silicon or polycrystalline silicon. However, the present disclosure is not limited thereto, and the active layer 307 may include various materials. As an alternative embodiment, the active layer 307 may include an organic semiconductor material.

[0097] As another optional embodiment, the active layer 307 may include an oxide semiconductor material. For example, the active layer 307 may include an oxide of a material selected from Group 12, 13, and 14 metal elements such as zinc (Zn), indium (In), gallium (Ga), tin (Sn), cadmium (Cd), or germanium (Ge), and combinations thereof.

[0098] The gate insulating layer 303 is formed on the active layer 307. The gate insulating layer 303 serves to insulate the active layer 307 and the gate electrode 308 from each other. The gate insulating layer 303 may be formed in a multi-layer or single-layer structure made of an inorganic material such as silicon oxide and / or silicon nitride.

[0099] The gate electrode 308 is formed above the gate insulating layer 303. The gate electrode 308 may be coupled to a gate line (not shown) that applies an on / off signal to the thin film transistor. The gate electrode 308 may be made of a low-resistance metal material. Considering the tightness between adjacent layers, the surface flatness of the stacked layers, and the processability, the gate electrode 308 may be formed to have a single-layer structure or a multi-layer structure using, for example, one or more materials of aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and copper (Cu).

[0100] The interlayer insulating layer 304 is formed on the gate electrode 308. The interlayer insulating layer 304 insulates the source electrode 309a and the drain electrode 309b from the gate electrode 308. The interlayer insulating layer 304 may be formed as a multi-layer or single-layer structure made of an inorganic material. For example, the inorganic material may be a metal oxide or a metal nitride, and the inorganic material may include silicon oxide (SiO 2 )、Silicon Nitride(SiN x )、Silicon Oxynitride (SiON), Aluminum Oxide (Al 2 O 3 ), titanium oxide (TiO 2 )、Tantalum oxide(Ta 2 O 5 )、HfO 2 ) or zinc oxide (ZnO 2 ).

[0101] The source electrode 309a and the drain electrode 309b are formed on the interlayer insulating layer 304. The source electrode 309a and the drain electrode 309b may be formed to have a single layer structure or a multilayer structure using one or more materials of aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and copper (Cu). The source electrode 309a and the drain electrode 309b are formed to contact a region of the active layer 307.

[0102] The planarization layer 305 is formed on the thin film transistor. The planarization layer 305 is formed to cover the thin film transistor, eliminate steps caused by the thin film transistor, and planarize the upper surface, thereby preventing defects from occurring in the emission layer 310 due to an uneven portion of a lower portion.

[0103] The planarization layer 305 may be formed to have a single-layer structure or a multi-layer structure using an organic material. The organic material may include a common commercial polymer (such as polymethyl methacrylate (PMMA) or polystyrene (PS)), a polymer derivative having a phenol group, an acrylic polymer, an imide polymer, an aryl ether polymer, an amide polymer, a fluoropolymer, a paraxylene polymer, a vinyl alcohol polymer, and a blend thereof. In addition, the planarization layer 305 may be formed by a composite stack of an inorganic insulating layer and an organic insulating layer.

[0104] The first electrode 311 and the emission layer 310 are located on the planarization layer 305 .

[0105] The first electrode 311 may be formed entirely on the pixel (or sub-pixel) region PA. In other words, the pixel (or sub-pixel) region PA may be defined by the first electrode 311. The first electrode 311 may be electrically coupled to the thin film transistor. More specifically, the first electrode 311 may be electrically coupled to the drain electrode 309b through a contact hole formed in the planarization layer 305. The first electrode 311 may have various shapes, such as being formed into an island pattern by patterning.

[0106] The first electrode 311 may include a reflective layer formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a mixture thereof and a transparent or semi-transparent electrode layer formed on the reflective layer. The transparent or semi-transparent electrode layer may include a layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In 2 O 3 ), at least one or more materials selected from the group consisting of indium gallium oxide (IGO) and aluminum zinc oxide (AZO).

[0107] The emission layer 310 may include the light emitting element 120 electrically coupled to the thin film transistor and a cladding layer 306 surrounding the light emitting element 120 .

[0108] The light emitting element 120 emits red, green or blue light and may realize white light by using a fluorescent material or by combining colors. The light emitting element 120 may include a first semiconductor layer 121 , a second semiconductor layer 123 , and an intermediate layer 122 interposed therebetween.

[0109] For example, the first semiconductor layer 121 may be implemented as a p-type semiconductor layer. The p-type semiconductor layer may be selected from a material having In x Al y Ga 1-x-y A semiconductor material having a composition formula of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN, and may be doped with a p-type dopant such as Mg, Zn, Ca, Sr, or Ba.

[0110] For example, the second semiconductor layer 123 may be formed to include an n-type semiconductor layer. The n-type semiconductor layer may be selected from a group consisting of In x Al y Ga 1-x-y A semiconductor material having a composition formula of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, and AlInN, and may be doped with an n-type dopant such as Si, Ge, or Sn.

[0111] However, the present disclosure is not limited thereto. In other words, the first semiconductor layer 121 may include an n-type semiconductor layer, and the second semiconductor layer 123 may include a p-type semiconductor layer.

[0112] The intermediate layer 122 is a region where electrons and holes are recombined. When the electrons and holes are recombined, the intermediate layer 122 may be transferred to a low energy level and generate light having a wavelength corresponding thereto. For example, the intermediate layer 122 may be formed to include a x Al y Ga 1-x-y The intermediate layer 122 may be formed as a single quantum well structure or a multiple quantum well (MQW) structure. In addition, a quantum wire structure or a quantum dot structure may be included.

[0113] The capping layer 306 is a layer for preventing oxygen and moisture from penetrating into the light emitting element 120 , and may be a planarization layer in which a step is prevented from being formed on the upper surface. The capping layer 306 may be formed to be higher than the plurality of light emitting elements 120 .

[0114] The second electrode 312 may be formed on the emission layer 310. The second electrode 312 may be formed entirely on the emission layer 310. The second electrode 312 may be a transparent or semi-transparent electrode and may be formed of a metal thin film having a low work function and including Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, or a mixture thereof. In addition, a metal such as ITO, IZO, ZnO, or In 2 O 3 The material for forming a transparent electrode further forms an auxiliary electrode layer or a bus electrode on the metal film. Therefore, the second electrode 312 can transmit light emitted from the light emitting element 120.

[0115] When the plurality of light emitting elements 120 pass Figures 12 to 18 When the method shown in FIG. 1 is disposed on the TFT array substrate 300, the light emitting elements 120 are disposed at regular intervals on the first electrode 311. In this case, the light emitting elements 120 may be randomly disposed without being aligned with other elements in the TFT array substrate 300.

[0116] It will be understood by those skilled in the art that the present disclosure may be implemented in different specific forms without changing the technical concept or essential features. Therefore, it should be understood that the exemplary embodiments are only for illustrative purposes and do not limit the scope of the present invention. The scope of the present disclosure is intended to be limited by the appended claims, and various modifications, additions and substitutions derived from the meaning, scope and equivalent concepts of the appended claims fall within the scope of the present disclosure.

Claims

1. A method for manufacturing a display device, the method comprising the following steps: forming a light-emitting element on the stretchable film; stretching the stretchable film; as well as The light emitting element is disposed on a first electrode disposed on a substrate, The step of arranging the light emitting element comprises transferring the light emitting element onto the first electrode without being aligned relative to the first electrode.

2. The method according to claim 1, wherein: The step of providing the light emitting elements comprises: arranging the light emitting elements on the substrate to be spaced apart at predetermined intervals, and The step of stretching the stretchable film includes: controlling the interval information of the light emitting elements so that the light emitting elements are spaced at the predetermined intervals on the stretchable film.

3. The method according to claim 1, wherein: The step of stretching the stretchable film includes stretching the stretchable film in two or more directions to uniformly change the interval between the light emitting elements from a first interval to a second interval greater than the first interval.

4. The method according to claim 1, wherein: The region where the first electrode is provided on the substrate is a transfer region where the light emitting element is configured to be transferred.

5. The method according to claim 4, wherein: The region does not include a non-transfer region to which the light emitting element is configured not to be transferred.

6. The method according to claim 1, wherein: The stretchable film comprises a support layer and an adhesive layer on the support layer, wherein the support layer is configured to transmit infrared laser light, and Wherein, when ultraviolet laser or heat is applied, the adhesive force of the adhesive layer is changed.

7. The method according to claim 6, wherein: The support layer and the adhesive layer are in contact with each other.

8. The method according to claim 6, wherein: The stretchable film includes a first surface corresponding to the light emitting element and a second surface corresponding to a region where the light emitting element is not disposed, and Wherein, the step of setting the light-emitting element includes: radiating the infrared laser onto the first surface of the stretchable film. 9 . The method according to claim 6 , further comprising removing the stretchable film from the light emitting element after the step of providing the light emitting element.

10. The method according to claim 9, wherein: The step of removing the stretchable film includes removing the untransferred light emitting element together with the stretchable film.

11. The method according to claim 10, wherein: In the step of removing the stretchable film, a first adhesive force between the light emitting element and the stretchable film is smaller than a second adhesive force between the light emitting element and the first electrode.

12. The method according to claim 11, wherein: The step of removing the stretchable film includes radiating ultraviolet laser or heat onto the stretchable film.

13. The method according to claim 1, wherein: The substrate further includes a transistor, a planarization layer on the transistor, and Wherein, the first electrode is arranged on the planarization layer, and The first electrode is electrically connected to the transistor through a via hole formed in the planarization layer.

14. The method according to claim 13, wherein: The light emitting element includes a first semiconductor layer, a second semiconductor layer, and an intermediate layer between the first semiconductor layer and the second semiconductor layer. The step of providing the light emitting element comprises: transferring the light emitting element so that the first semiconductor layer faces the first electrode, and Wherein, the first electrode is an anode.

15. The method according to claim 13, wherein: The first electrode includes a reflective layer and a transparent or semi-transparent layer on the reflective layer.

16. The method according to claim 13, further comprising the steps of: forming a capping layer on the planarization layer to cover the light emitting element; etching at least a portion of the cladding layer so that an end portion of each of the light emitting elements is exposed; as well as forming a second electrode on the etched capping layer, The second electrode is formed to cover the entire area of ​​the etched capping layer.

17. The method according to claim 1, further comprising: placing the light-emitting element on an additional stretchable film; and stretching the additional stretchable film.

18. The method according to claim 17, wherein: The spacing between the light emitting elements on the stretchable film is smaller than the spacing between the light emitting elements on the additional stretchable film after the step of stretching the additional stretchable film.

19. A display device, comprising: a substrate, including a pixel region; A first electrode, entirely disposed in the pixel region of the substrate; as well as a light emitting element, electrically connected to the first electrode and disposed on the first electrode, Wherein, the light emitting element is not aligned with the first electrode.

20. The display device according to claim 19, wherein: The first electrode is disposed on the entire area of ​​the pixel region.

21. The display device according to claim 20, further comprising a second electrode electrically connected to the light emitting element, in, The light emitting elements are randomly arranged in the entire area, and Wherein, the second electrode entirely covers the upper portion of the light emitting element.

22. The display device according to claim 21, wherein: The first electrode is an anode, and Wherein, the second electrode is a cathode.

23. The display device according to claim 22, further comprising a covering layer covering a side surface of each of the light emitting elements and a portion of the first electrode on which the light emitting element is not disposed, in, The second electrode entirely covers the cover layer.

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