Display device and manufacturing method of display device

Abstract

A display device and a manufacturing method of a display device are provided. The display device includes a base substrate, an electrode on the base substrate, a light emitting element on the base substrate and electrically connected to the electrode, and a solution layer between the base substrate and the light emitting element, the solution layer including a light blocking material.

Description

[0001] Cross-reference to related applications

[0002] This patent application claims priority and benefit to Korean Patent Application No. 10-2019-0041351, filed with the Korean Intellectual Property Office on April 9, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments of this disclosure relate to a display device and a method of manufacturing the display device. Background Technology

[0004] Light-emitting diodes (LEDs) are devices that use the properties of compound semiconductors to convert electrical signals into light, including infrared and visible light. They can be used in home appliances, remote controllers, electronic boards, and various types of automated equipment. The application of LEDs is gradually expanding to a wide range of electronic devices, from small handheld electronic devices to large display devices.

[0005] An LED may include a p-type semiconductor layer, an n-type semiconductor layer, and at least one quantum well layer interposed between the p-type semiconductor layer and the n-type semiconductor layer. Summary of the Invention

[0006] According to aspects of embodiments of the present disclosure, a display device in which reflection of external light is prevented or substantially prevented to improve reliability, and a method of manufacturing the display device, are provided. According to aspects of embodiments of the present disclosure, a display device including a transparent light-emitting diode is provided, and a method of manufacturing the display device is provided, in which incident external light is prevented or substantially prevented from potentially transmitting through the transparent light-emitting diode and being reflected by a reflective electrode, thus preventing problems such as the reflective electrode being observable, thereby improving the reliability of the display device.

[0007] According to one or more embodiments of the present invention, a display device includes: a base substrate; an electrode located on the base substrate; a light-emitting element located on the base substrate and electrically connected to the electrode; and a solution layer located between the base substrate and the light-emitting element, wherein the solution layer includes a light-blocking material.

[0008] In one embodiment, the light-emitting element may include a contact portion of a contact electrode, and a solution layer surrounds the contact portion.

[0009] In an embodiment, the electrode may include a first electrode and a second electrode spaced apart from the first electrode, and the contact portion may include: a first contact portion connected to the first electrode; and a second contact portion connected to the second electrode.

[0010] In an embodiment, the light emitting element can further include a base layer, a first semiconductor layer on the base layer, a second semiconductor layer on the first semiconductor layer, a first element electrode on the second semiconductor layer and connected to the first contact part, and a second element electrode on the first semiconductor layer and connected to the second contact part.

[0011] In an embodiment, the light emitting element can further include an element insulating layer covering at least a portion of the first element electrode and the second element electrode, and the solution layer can be in contact with the first contact part, the second contact part, and the element insulating layer.

[0012] In an embodiment, the electrode can include gold (Au) or copper (Cu).

[0013] In an embodiment, the solution layer can include a water-soluble solvent and a sodium salt dissolved in the water-soluble solvent, wherein the sodium salt can have a black color.

[0014] In an embodiment, the solution layer can include an organic solvent and a black organic pigment dispersed in the organic solvent.

[0015] In an embodiment, the display apparatus can further include a pixel definition layer on the base substrate and covering a portion of the electrode, wherein an opening exposing a portion of the electrode other than the portion is defined in the pixel definition layer, and the light emitting element and the solution layer are in the opening.

[0016] In an embodiment, the light emitting element can be a micro LED element.

[0017] In an embodiment, the display apparatus can further include a planarization layer on the light emitting element and the solution layer.

[0018] In an embodiment, the contact part can include tin (Sn), and further include at least one of copper (Cu), silver (Ag), and gold (Au).

[0019] In one or more embodiments of the inventive concept, a method of manufacturing a display apparatus includes forming an electrode on a base substrate, forming a solution layer by providing a solution including a light-blocking material on the electrode, transferring a light emitting element such that the light emitting element passes through the solution layer and is electrically connected to the electrode, and bonding the light emitting element to the electrode by applying light or heat to a portion where the light emitting element is connected to the electrode.

[0020] In an embodiment, the light emitting element can include a contact part, and during the transferring of the light emitting element, the transferring is performed such that the contact part contacts the electrode.

[0021] In an embodiment, the electrode can include copper (Cu) or gold (Au), the contact part can include tin (Sn), and during the applying of the light or the heat, the contact part can be bonded to the electrode.

[0022] In an embodiment, during forming the electrode, a first electrode and a second electrode spaced apart from the first electrode can be formed, the contact portion can include a first contact portion and a second contact portion spaced apart from the first contact portion, and during transferring the light emitting element, the transferring can be performed such that the first contact portion is connected to the first electrode and the second contact portion is connected to the second electrode.

[0023] In an embodiment, during transferring the light emitting element, the transferring can be performed such that the contact portion and the electrode are completely covered by the solution layer.

[0024] In an embodiment, the manufacturing method can further include, after bonding the light emitting element and the electrode, removing the solution layer.

[0025] In an embodiment, the manufacturing method can further include, on the base substrate, forming a pixel definition layer covering a portion of the electrode, wherein, during transferring the light emitting element, the light emitting element is transferred in an opening of the pixel definition layer defined to expose a portion of the electrode other than the portion.

[0026] In an embodiment, during bonding the light emitting element and the electrode, a portion where the light emitting element is connected to the electrode can be irradiated with light by an infrared laser, or can be applied with heat by at least one of an IR reflow oven, a convection oven, or a hot plate. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are included to provide a further understanding of the present concept and are incorporated in and constitute a part of this specification, illustrate some example embodiments of the present concept and together with the description serve to explain the present concept. In the drawings:

[0028] Figure 1 is a perspective view of a display apparatus according to an embodiment of the present concept;

[0029] Figure 2 is a block diagram of a display apparatus according to an embodiment of the present concept;

[0030] Figure 3 is an equivalent circuit diagram of a pixel according to an embodiment of the present concept;

[0031] Figure 4 is a cross-sectional view of a display apparatus according to an embodiment of the present concept;

[0032] Figure 5 is a cross-sectional view of a display apparatus according to another embodiment of the present concept;

[0033] Figure 6is a cross-sectional view of a display device according to another embodiment of the present inventive concept;

[0034] Figure 7 is a cross-sectional view of a light emitting element according to an embodiment of the present inventive concept;

[0035] Figure 8 is a cross-sectional view showing a state in which a light emitting element according to an embodiment of the present inventive concept is connected to an electrode;

[0036] Figure 9 is a flowchart showing a manufacturing method of a display device according to an embodiment of the present inventive concept; and

[0037] Figures 10A to 10E is a cross-sectional view sequentially showing a manufacturing method of a display device according to an embodiment of the present inventive concept. DETAILED DESCRIPTION

[0038] Embodiments of the present inventive concept will be described more fully hereinafter with reference to the accompanying drawings. The present inventive concept can be variously modified and implemented, and thus, some example embodiments will be illustrated in the drawings and described further in detail in the text. However, it is to be understood that the present inventive concept is not intended to be limited to the particular forms disclosed in the text, but includes all modifications, equivalents, and alternatives falling within the technical scope and spirit of the present inventive concept.

[0039] Referring to the drawings, like reference numerals refer to like elements throughout. In the drawings, the size of the structures can be exaggerated for clarity. Terminologies such as "first", "second", and the like can be used to describe various components, but the components are not limited by the terminologies. The terminologies are used for the purpose of distinguishing one component from another component only. For example, a first component could be termed a second component, and, similarly, a second component could be termed a first component without departing from the scope of the present disclosure. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0040] It will be further understood that the terms "comprises" and / or "comprising", or "includes" and / or "including" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0041] It will also be understood that when a part such as a layer, film, region or plate is referred to as being "on" or "above" another part, it can be directly on the other part, or intervening parts can also be present. In addition, such as when a part such as a layer, film, region or plate is referred to as being "below" another part, it can be directly below the other part, or intervening parts can also be present. In addition, disposed "on" can include both upward and downward orientations.

[0042] Meanwhile, "direct contact" can mean that there is no additional layer, film, region, plate, etc. between a part such as a layer, film, region or plate and another part. For example, "direct contact" can mean that no additional member such as an adhesive member is used between two layers or two members.

[0043] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept belongs. Such terms, as defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0044] In this document, display apparatuses according to embodiments of the inventive concept will be described with reference to the accompanying drawings.

[0045] Figure 1 is a perspective view of a display apparatus according to an embodiment of the inventive concept.

[0046] Referring to Figure 1 The display apparatus DD can display an image through a display area DA. Figure 1 The display area DA is exemplarily shown as being disposed on a surface defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. However, embodiments of the inventive concept are not limited thereto, and in another embodiment of the inventive concept, a display area of a display apparatus can be disposed on a curved surface.

[0047] A thickness direction of the display apparatus DD is indicated by a third direction DR3. The directions indicated by the first direction DR1, the second direction DR2 and the third direction DR3 are relative concepts and can change to other directions. In this disclosure, the wording "in a plan view" can mean a case observed in the third direction DR3. In addition, "thickness direction" can mean the third direction DR3.

[0048] In Figure 1In the embodiment, the display device DD can include a display panel DP, a signal control unit (or a timing controller) TC, a data driving unit DDV, and a scan driving unit GDV. Each of the signal control unit TC, the data driving unit DDV, and the scan driving unit GDV can include a circuit.

[0049] Figure 2 is a block diagram of a display device according to an embodiment of the inventive concept.

[0050] Referring to Figure 2 , the display device DD can include a display panel DP, a signal control unit (or a timing controller) TC, a data driving unit DDV, and a scan driving unit GDV. Each of the signal control unit TC, the data driving unit DDV, and the scan driving unit GDV can include a circuit.

[0051] In the embodiment, the display panel DP can be a micro light emitting element display panel including micro light emitting elements. For example, the display panel DP can be a micro LED display panel.

[0052] The display panel DP can include a plurality of data lines DL1 to DLm, a plurality of scan lines SL1 to SLn, and a plurality of pixels PX.

[0053] The plurality of data lines DL1 to DLm can extend in a first direction DR1 and can be arranged along a second direction DR2 intersecting the first direction DR1. The plurality of scan lines SL1 to SLn can extend in the second direction DR2 and can be arranged along the first direction DR1.

[0054] Each of the pixels PX can include a light emitting element ED (see Figure 3 ) and a pixel circuit PXC (see Figure 3 ) electrically connected to the light emitting element ED. The pixel circuit PXC (see Figure 3 ) can include a plurality of transistors TR1 and TR2 (see Figure 3 ). A first power voltage ELVDD and a second power voltage ELVSS can be supplied to each of the pixels PX.

[0055] In a plan view of the display panel DP, the pixels PX can be arranged in a regular pattern. Each of the pixels PX can display one of primary colors or one of mixed colors. The primary colors can include red, green, and blue, and the mixed colors can include various colors such as yellow, cyan, magenta, and white. However, the colors displayed by the pixels PX are not limited thereto.

[0056] The signal control unit TC can receive image data RGB provided from the outside. In order to be suitable for the operation of the display panel DP, the signal control unit TC converts the image data RGB to generate converted image data R'G'B', and outputs the converted image data R'G'B' to the data drive unit DDV.

[0057] In addition, the signal control unit TC can receive a control signal CS provided from the outside. The control signal CS can include a vertical synchronization signal, a horizontal synchronization signal, a main clock signal, a data enable signal, and the like.

[0058] The signal control unit TC provides a first control signal CONT1 to the data drive unit DDV, and provides a second control signal CONT2 to the scan drive unit GDV. The first control signal CONT1 is used to control the data drive unit DDV, and the second control signal CONT2 is used to control the scan drive unit GDV.

[0059] In response to the first control signal CONT1 received from the signal control unit TC, the data drive unit DDV can provide electrical signals to the plurality of data lines DL1 to DLm. In an embodiment, the data drive unit DDV can be implemented as a separate integrated circuit, and can be electrically connected to one side of the display panel DP, or can be directly mounted on the display panel DP. In addition, the data drive unit DDV can be implemented as a single chip or include a plurality of chips.

[0060] In response to the second control signal CONT2 received from the signal control unit TC, the scan drive unit GDV can provide electrical signals to the plurality of scan lines SL1 to SLn. In an embodiment, the scan drive unit GDV can be integrated in a designated area of the display panel DP. For example, the scan drive unit GDV can include a plurality of transistors formed by the same process as a process (e.g., a low temperature polysilicon (LTPS) process or a low temperature polysilicon oxide (LTPO) process) of a pixel circuit PXC (see Figure 3 ) of the pixel PX. In another embodiment of the present inventive concept, the scan drive unit GDV can be implemented as a separate integrated circuit chip to be electrically connected to one side of the display panel DP.

[0061] When a gate-on voltage is applied to one of the plurality of scan lines SL1 to SLn, each of the switch transistors in a row of pixels PX connected to the one of the plurality of scan lines is turned on. At this time, the data drive unit DDV provides a data drive signal to the data lines DL1 to DLm. The data drive signal provided to the data lines DL1 to DLm is respectively applied to the corresponding pixels PX through the turned-on switch transistors. The data drive signal can be an analog voltage corresponding to a gray value of a plurality of image data.

[0062] Figure 3 This is an equivalent circuit diagram of a pixel according to an embodiment of the present invention. Figure 3 It shows Figure 2 The equivalent circuit diagram of one of the multiple pixels PX shown (referred to as a pixel in this document).

[0063] See Figure 3 Pixel PX can be connected to multiple signal lines. In this embodiment, scan line SLi, data line DLj, first power line PL1, and second power line PL2 are shown as exemplary signal lines. However, this illustration is merely an example, and pixel PX according to embodiments of the present invention can be additionally connected to various signal lines and is not limited to any particular embodiment.

[0064] A pixel PX may include a light-emitting element (ED) and a pixel circuit PXC. The pixel circuit PXC may include a first transistor TR1, a capacitor CAP, and a second transistor TR2. This illustration is merely an example, and the number of transistors and capacitors included in the pixel circuit PXC is not limited to this. Figure 3 Those shown. For example, in another embodiment of the inventive concept, the pixel circuit PXC may include seven transistors and a capacitor.

[0065] The first transistor TR1 can be a switching transistor used to control the on or off state of pixel PX. The first transistor TR1 can deliver or cut off the data signal delivered via data line DLj in response to the scan signal delivered via scan line SLi.

[0066] Capacitor CAP is connected to the first transistor TR1 and the first power line PL1. Capacitor CAP is charged using the amount of charge corresponding to the difference between the data signal delivered from the first transistor TR1 and the first power supply voltage ELVDD applied to the first power line PL1.

[0067] The second transistor TR2 is connected to the first transistor TR1, the capacitor CAP, and the light-emitting element ED. The second transistor TR2 controls the drive current flowing through the light-emitting element ED based on the amount of charge stored in the capacitor CAP. The on-time of the second transistor TR2 can be determined based on the amount of charge stored in the capacitor CAP.

[0068] Each of the first transistor TR1 and the second transistor TR2 can be an n-type transistor or a p-type transistor. In another embodiment of the present invention, one of the first transistor TR1 and the second transistor TR2 can be an n-type transistor, and the other can be a p-type transistor.

[0069] The light-emitting element ED can be electrically connected to the second transistor TR2 and the second power line PL2. The light-emitting element ED can receive the second power supply voltage ELVSS through the second power line PL2.

[0070] The light-emitting element ED can emit light at a voltage corresponding to the difference between the signal delivered through the second transistor TR2 and the second power supply voltage ELVSS received through the second power line PL2.

[0071] The light-emitting element (ED) can be a miniature light-emitting diode (miniature LED). A miniature LED element can be an LED element with a length ranging from a few nanometers to hundreds of micrometers. However, this length of a miniature LED element is merely an example, and implementations are not limited to the above numerical range. The ED can emit light in a specific wavelength band. For example, the ED can emit blue, red, or green light.

[0072] As an example, Figure 3 A light-emitting element ED is shown connected between the second transistor TR2 and the second power line PL2, but multiple light-emitting elements ED can be provided. In an embodiment, multiple light-emitting elements ED can be connected in parallel to each other.

[0073] Figure 4 This is a cross-sectional view of a display device according to an embodiment of the present invention. Figure 4 An example is shown in which Figure 2 The three pixels PX shown are arranged side by side on a cross section of the base substrate BS of the display device DD according to an embodiment of the present invention.

[0074] refer to Figure 4 The display device DD according to an embodiment of the present invention may include a base substrate BS, a circuit element layer CL disposed on the base substrate BS, and at least one light-emitting element ED disposed on the circuit element layer CL.

[0075] In this embodiment, the base substrate BS may include a synthetic resin substrate or a glass substrate. The circuit element layer CL includes at least one insulating layer and circuit elements. The circuit elements include signal lines and pixel driving circuits, etc. The circuit element layer CL can be formed by processes such as coating and deposition to form insulating, semiconductor, and conductive layers, and by processes such as patterning insulating, semiconductor, and conductive layers via photolithography.

[0076] In this embodiment, the circuit element layer CL may include a buffer film BFL, a first insulating layer 10, a second insulating layer 20, and a third insulating layer 30. In this embodiment, the first insulating layer 10 and the second insulating layer 20 may be inorganic films, and the third insulating layer 30 may be an organic film. In this embodiment, the third insulating layer 30 may include polyimide (PI).

[0077] Figure 4 The arrangement relationship between the semiconductor pattern OSP constituting the drive transistor TD, the control electrode GE, the input electrode DE, and the output electrode SE is exemplarily shown. The first through-hole CH1, the second through-hole CH2, and the third through-hole CH3 are also shown as examples. However, the embodiments of the present inventive concept are not limited thereto, and the structure of the drive transistor TD can have any of various shapes for driving the light emitting element ED. For example, in the embodiments of the present inventive concept, the drive transistor TD can have a shape in which the first transistor TR1 (see Figure 3 ) and the second transistor TR2 (see Figure 3 ) are connected by a connection electrode.

[0078] One or more electrodes E1 and E2 are provided on the circuit element layer CL. The first electrode E1 and the second electrode E2 can be provided on the circuit element layer CL. The first electrode E1 is provided on the third insulating layer 30 and is electrically connected to the output electrode SE exposed through the third through-hole CH3.

[0079] The second electrode E2 can be provided on the third insulating layer 30. Although not shown, the second electrode E2 can be electrically connected to the second power line PL2 (see Figure 3 ). In other words, the second electrode E2 can be supplied with the second power supply voltage ELVSS (see Figure 3 ).

[0080] In the embodiments, the first electrode E1 and the second electrode E2 are provided on the same layer and can be separately provided or spaced apart from each other. In the embodiments, the first electrode E1 and the second electrode E2 can include the same conductive material. For example, each of the first electrode E1 and the second electrode E2 can include a reflective material. Each of the first electrode E1 and the second electrode E2 can have a single layer structure or a stacked structure of a plurality of layers. In the embodiments, each of the first electrode E1 and the second electrode E2 can include molybdenum, silver, titanium, copper, aluminum, gold, or an alloy thereof. In the embodiments, each of the first electrode E1 and the second electrode E2 can include copper (Cu) or gold (Au). However, the embodiments of the present inventive concept are not limited thereto, and each of the first electrode E1 and the second electrode E2 can have a structure in which indium tin oxide (ITO), silver (Ag), and indium tin oxide (ITO) are sequentially stacked. For example, each of the first electrode E1 and the second electrode E2 can include at least one of indium zinc oxide (IZO), indium tin oxide (ITO), indium gallium oxide (IGO), indium zinc gallium oxide (IGZO), and a mixture / compound thereof.

[0081] The light emitting element ED can be disposed on and electrically connected to the first and second electrodes E1 and E2.

[0082] The light emitting element ED can be transferred onto the first and second electrodes E1 and E2. For example, the light emitting element ED can be disposed in plural, and the plural light emitting elements can be transferred substantially in parallel (e.g., simultaneously), or each of the plural light emitting elements can be transferred individually.

[0083] The method for transferring the light emitting element ED onto the first and second electrodes E1 and E2 can include any of a direct transfer method and a printing transfer method. The direct transfer method can be a method in which the light emitting element ED is directly transferred or transported onto the first and second electrodes E1 and E2. The printing transfer method can be a method in which the light emitting element ED is transferred or transported onto the first and second electrodes E1 and E2 using an electrostatic head, a flat stamp, or a roll stamp.

[0084] The light emitting element ED can include a contact portion CT and a main body portion EM. The contact portion CT can contact the first and second electrodes E1 and E2 to be electrically connected with the first and second electrodes E1 and E2. In an embodiment, the contact portion CT can include a first contact portion CT1 contacting the first electrode E1 to be electrically connected with the first electrode E1 and a second contact portion CT2 contacting the second electrode E2 to be electrically connected with the second electrode E2. As Figure 4 As shown in FIG. 1B, when the first and second contact portions CT1 and CT2 are disposed side by side under the main body portion EM, the light emitting element ED according to an embodiment can be a horizontal light emitting element.

[0085] The contact portion CT can include a metal. In an embodiment, the contact portion CT can include tin (Sn). In an embodiment, the contact portion CT can include tin, and further include at least one of copper (Cu), silver (Ag), and gold (Au). In an embodiment, the contact portion CT can be an alloy of tin / gold, or an alloy of tin / silver / copper.

[0086] The main body portion EM can include at least one semiconductor layer and an active layer, and substantially generate light by an electric signal. Herein, a configuration of the main body portion EM of the light emitting element ED will be described in more detail with reference to FIGS. 2A and 2B. Figure 7 and Figure 8 A configuration of the main body portion EM of the light emitting element ED will be described in more detail with reference to FIGS. 2A and 2B.

[0087] A pixel definition layer PDL can be provided on the third insulating layer 30. The pixel definition layer PDL can cover a part of the first and second electrodes E1 and E2, and expose the remaining part other than the covered part. In more detail, an opening PDL-OP corresponding to a pixel area is defined in the pixel definition layer PDL to cover the periphery of the first and second electrodes E1 and E2, and the remaining part of the first and second electrodes E1 and E2 is exposed through the opening PDL-OP. The pixel definition layer PDL can include a light-blocking material. The light-blocking material included in the pixel definition layer PDL can be the same as the light-blocking material included in the solution layer SL which will be described later. In an embodiment of the inventive concept, the pixel definition layer PDL can be omitted.

[0088] Although not shown, in an embodiment, a separate light-blocking pattern can be provided on or under the pixel definition layer PDL. The light-blocking pattern can be provided on a top surface of the pixel definition layer PDL, or can be provided between the third insulating layer 30 and the pixel definition layer PDL. The light-blocking pattern can include a light-blocking material. In an embodiment, the light-blocking pattern can include a light-blocking material having a black color. The light-blocking material included in the light-blocking pattern can be the same as the light-blocking material included in the solution layer SL which will be described later.

[0089] The solution layer SL is provided between the first and second electrodes E1 and E2 and the light emitting element ED. The solution layer SL can cover the exposed top surfaces of the first and second electrodes E1 and E2. The solution layer SL can fill a separation part or area defined between the first and second electrodes E1 and E2, and contact the top surface of the third insulating layer 30 exposed by the separation part.

[0090] The solution layer SL can contact the contact part CT of the light emitting element ED which contacts the first and second electrodes E1 and E2. In an embodiment, the solution layer SL can completely cover the contact part CT of the light emitting element ED. In more detail, the contact part CT can include a side surface defined between a top surface connected to the main body part EM and a bottom surface connected to the electrodes E1 and E2, and the solution layer SL can completely cover the exposed side surface of the contact part CT. The solution layer SL can contact the contact part CT and the main body part EM of the light emitting element ED, and cover a part of the bottom surface and the side surface of the main body part EM.

[0091] The solution layer SL can include a solvent and a light-blocking material. In an embodiment, the solution layer SL can include a water-soluble solvent and a water-soluble light-blocking material dissolved in the water-soluble solvent. The water-soluble light-blocking material can include a sodium salt. In an embodiment, the water-soluble light-blocking material can have a black color.

[0092] In an embodiment, the solution layer SL can include an organic solvent and a black organic pigment dispersed in the organic solvent. The organic solvent can be, for example, acetone, ethanol, or the like. The black pigment dispersed in the organic solvent can be, for example, aniline black, carbon black, graphite, or the like.

[0093] The solution layer SL can include a light-blocking material to block external light. If the solution layer SL includes a transparent or semi-transparent material, external light will be incident and reflected by the electrodes E1 and E2 including a reflective material, and thus the electrodes E1 and E2, etc. can be possibly observed from the outside. However, in the display device DD according to the embodiment of the present inventive concept, the solution layer SL including the light-blocking material is disposed between the light emitting element ED and the electrodes E1 and E2 to effectively block external light, and thus, the problem that the electrodes disposed inside, etc. can be possibly observed from the outside can be prevented or substantially prevented.

[0094] Figure 5 and Figure 6 are cross-sectional views of display devices according to other embodiments of the present inventive concept. Herein, when describing the display device DD-1 and the display device DD-2 of Figure 5 and Figure 6 , the same reference numerals can be given to the same elements as the above-described elements in Figure 4 , and a repeated description thereof can be omitted.

[0095] Referring to Figure 5 , the display device DD-1 according to the embodiment of the present inventive concept can include a vertical light emitting element ED-1. In the light emitting element ED-1, the first contact portion CT1-1 and the second contact portion CT2-1 can be disposed on the lower portion and the upper portion of the body portion EM, respectively.

[0096] Since the display device DD-1 includes the vertical light emitting element ED-1, the first electrode E1-1 and the second electrode E2-1 can not be disposed on the same layer, but can be disposed to be connected to the first contact portion CT1-1 and the second contact portion CT2-1, respectively. In more detail, the first electrode E1-1 can be disposed on the third insulating layer 30 to be electrically connected to the first contact portion CT1-1, and the second electrode E2-1 can be disposed on the pixel definition layer PDL and the light emitting element ED-1 to be electrically connected to the second contact portion CT2-1.

[0097] Referring to Figure 6The display device DD-2 according to the embodiment of the present inventive concept can further include a planarization layer PL disposed on the light emitting element ED and the pixel definition layer PDL. The planarization layer PL can cover the light emitting element ED and the pixel definition layer PDL to provide a planarized surface to the top portion. The planarization layer PL can be used to remove and planarize steps caused by a height difference between the light emitting element ED and the pixel definition layer PDL, and cover the light emitting element ED to prevent or substantially prevent foreign substances from entering.

[0098] Figure 7 is a cross-sectional view of a light emitting element according to an embodiment of the present inventive concept; and Figure 8 is a cross-sectional view illustrating a state in which a light emitting element according to an embodiment of the present inventive concept is connected to an electrode. In Figure 7 and Figure 8 , a light emitting element ED included in a display device DD shown in Figure 4 is exemplarily illustrated, i.e., a horizontal light emitting element.

[0099] Referring to Figure 7 , the light emitting element ED according to the embodiment of the present inventive concept can include a base layer BSL, a first semiconductor layer SM1, a second semiconductor layer SM2, a first element electrode LE1, a second element electrode LE2, a first contact portion CT1, a second contact portion CT2, and an element insulating layer ISL.

[0100] The base layer BSL can include a material having a light-transmitting property, e.g., any one of sapphire, GaN, ZnO, and AlO. The base layer BSL is a substrate suitable for forming a semiconductor layer thereon, and can be formed of a carrier wafer. The base layer BSL can be a conductive substrate or an insulating substrate.

[0101] In the light emitting element ED according to the embodiment of the present inventive concept, the first semiconductor layer SM1 can be disposed on the base layer BSL. The second semiconductor layer SM2 can be disposed on the first semiconductor layer SM1. In an embodiment, the first semiconductor layer SM1 and the second semiconductor layer SM2 can be an n-type semiconductor layer and a p-type semiconductor layer, respectively. The n-type semiconductor layer can be provided by doping a semiconductor layer with an n-type dopant, and the p-type semiconductor layer can be provided by doping a semiconductor layer with a p-type dopant. In an embodiment, the first semiconductor layer SM1 can be an n-type semiconductor layer, and the second semiconductor layer SM2 can be a p-type semiconductor layer.

[0102] Each of the first semiconductor layer SM1 and the second semiconductor layer SM2 can include a semiconductor material. The semiconductor material can be, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, or AlInN. The n-type dopant can be silicon (Si), germanium (Ge), tin (Sn), selenium (Se), tellurium (Te), or a combination thereof. The p-type dopant can be magnesium (Mg), zinc (Zn), calcium (Ca), strontium (Sr), or barium (Ba), or a combination thereof.

[0103] Although not shown, an active layer can be disposed between the first semiconductor layer SM1 and the second semiconductor layer SM2. The active layer can be formed of at least one of a single quantum well structure, a multiple quantum well structure, a quantum wire structure, and a quantum dot structure. The active layer can be a region in which electrons injected through an n-type semiconductor layer and holes injected through a p-type semiconductor layer recombine. The active layer can be a layer from which light having an energy determined by the energy band of the material is emitted. The position of the active layer can vary in various ways according to the kind of the light emitting element ED.

[0104] The first element electrode LE1 can be disposed on the second semiconductor layer SM2. The second element electrode LE2 can be disposed on the first semiconductor layer SM1 and spaced apart from the second semiconductor layer SM2. In an embodiment, the second semiconductor layer SM2 can be disposed at one side of the first semiconductor layer SM1, and the second element electrode LE2 can be disposed at the other side of the first semiconductor layer SM1 so as not to overlap the second semiconductor layer SM2 in a plan view. The first element electrode LE1 can be a p-type electrode, and the first contact portion CT1 is disposed on the first element electrode LE1. The second element electrode LE2 can be an n-type electrode, and the second contact portion CT2 is disposed on the second element electrode LE2.

[0105] The element insulating layer ISL can be disposed on and cover the first semiconductor layer SM1, the second semiconductor layer SM2, the first element electrode LE1, and the second element electrode LE2. The element insulating layer ISL can include a transparent or semi-transparent insulating material, and is disposed between the components of the light emitting element ED to insulate each component.

[0106] Reference Figure 8 The light emitting element ED can be disposed on and electrically connected to the first electrode E1 and the second electrode E2. The first contact portion CT1 and the second contact portion CT2 of the light emitting element ED can pass through the solution layer SL to be electrically connected to the first electrode E1 and the second electrode E2. The first contact portion CT1 can be connected to the first electrode E1, and the second contact portion CT2 can be connected to the second electrode E2.

[0107] In an embodiment, the solution layer SL can contact each component of the light emitting element ED. The solution layer SL can be disposed to cover a portion in which the contact portions CT1 and CT2 are in contact with the electrodes E1 and E2, and to contact the element insulating layer ISL of the light emitting element ED and the contact portions CT1 and CT2. In a state in which the light emitting element ED is connected to the electrodes E1 and E2, the first semiconductor layer SM1, the second semiconductor layer SM2, the first element electrode LE1, the second element electrode LE2, the first contact portion CT1, and the second contact portion CT2 of the light emitting element ED can be covered by the element insulating layer ISL and the solution layer SL so as not to be exposed to the outside.

[0108] In this document, a manufacturing method of a display apparatus according to an embodiment of the inventive concept will be described with reference to the accompanying drawings.

[0109] Figure 9 is a flowchart illustrating a manufacturing method of a display apparatus according to an embodiment of the inventive concept; and Figures 10A to 10E is a cross-sectional view sequentially illustrating a manufacturing method of a display apparatus according to an embodiment of the inventive concept.

[0110] Referring to Figure 9 , the manufacturing method of a display apparatus according to an embodiment of the inventive concept includes a process S1 in which electrodes are formed on a base substrate, a process S2 in which a solution layer is formed on the electrodes, a process S3 in which a light emitting element is transferred to pass through the solution layer and to be electrically connected to the electrodes, and a process S4 in which the light emitting element is bonded with the electrodes.

[0111] Referring to Figure 9 and Figure 10A , the electrodes E1 and E2 are formed on the base substrate BS. The electrodes E1 and E2 can include a first electrode E1 and a second electrode E2. In an embodiment, the first electrode E1 and the second electrode E2 can be formed by depositing copper (Cu) or gold (Au) on the base substrate BS and then patterning the deposited copper (Cu) or gold (Au).

[0112] In the manufacturing method of a display apparatus according to an embodiment of the inventive concept, a process in which a pixel definition layer PDL is formed on the base substrate BS can be further included. The pixel definition layer PDL can be formed by coating an organic material and then patterning the organic material to form an opening PDL-OP to expose a portion of the electrodes E1 and E2. The pixel definition layer PDL can be formed by patterning an organic material including a light blocking material.

[0113] Referring to Figure 9 and Figure 10BThe solution layer SL can be formed by patterning a solution including a light-blocking material on the electrodes E1 and E2. The solution layer SL can be formed from a solution in which a light-blocking material is dispersed or dissolved in a solvent. The solution layer SL can be formed by patterning a solution including a light-blocking material in the openings PDL-OP of the pixel definition layer PDL. The solution layer SL can be formed to fill the separated portions defined between the first electrode E1 and the second electrode E2, and to contact the top surface of the third insulating layer 30 exposed by the separated portions.

[0114] Referring to Figure 9 , Figure 10C and Figure 10D , a process is included in which the light emitting element ED is transferred so that the light emitting element ED passes through the solution layer SL to be electrically connected to the electrodes E1 and E2. The light emitting element ED can include contact portions CT1 and CT2 (see Figure 7 ), and the contact portions CT1 and CT2 can be transferred to contact the electrodes E1 and E2. In more detail, the contact portions CT1 and CT2 can include a first contact portion CT1 and a second contact portion CT2, and be transferred so that the first contact portion CT1 is connected to the first electrode E1 and the second contact portion CT2 is connected to the second electrode E2. In an embodiment, in the process in which the light emitting element ED is transferred, the electrodes E1 and E2 and the contact portions CT1 and CT2 of the light emitting element ED can be buried in the solution layer SL and completely covered by the solution layer SL when the light emitting element ED passes through the solution layer SL is transferred.

[0115] Referring to Figure 9 and Figure 10D , a process is included in which light L or heat is applied to portions of the light emitting element ED connected to the electrodes E1 and E2, and the light emitting element ED is joined to the electrodes E1 and E2. The light L or heat can be applied to portions of the light emitting element ED in which the contact portions CT1 and CT2 are in contact with the electrodes E1 and E2. In an embodiment, the electrodes E1 and E2 can be formed of copper (Cu) or gold (Au), the contact portions CT1 and CT2 can be formed of an alloy of tin (Sn), and in the process of applying the light L or heat, the metals forming the contact portions CT1 and CT2 and the metals forming the electrodes E1 and E2 are melted and bonded to each other. In an embodiment, the light L can be applied by an infrared (IR) laser. In Figure 10D , the light L is exemplarily shown as being applied to portions of the light emitting element ED connected to the electrodes E1 and E2, but embodiments of the inventive concept are not limited thereto. Heat can be applied to portions of the light emitting element ED connected to the electrodes E1 and E2, and the light emitting element ED is joined to the electrodes E1 and E2. The heat can be applied, for example, by any one of an IR reflow oven, a convection oven, and a hot plate.

[0116] In the manufacturing method of the display apparatus according to the embodiments of the present inventive concept, a process in which, when the contact portion of the light emitting element including the metal and the electrode are joined, the portions to be joined are melted and bonded using light or heat can be included. For example, in the manufacturing method of the display apparatus according to the embodiments, a process in which the portions to be joined at which the contact portion of the light emitting element and the electrode are connected are melted by irradiation with an IR laser, and then bonded can be included. In the manufacturing method of the display apparatus according to the embodiments, since the joined portions between the contact portion and the electrode are covered by the solution layer, the portions to be joined can be prevented or substantially prevented from being oxidized, and the joining with the IR laser can be simplified. In addition, in the manufacturing method of the display apparatus according to the embodiments, the solution layer includes a light blocking material to prevent or substantially prevent the IR laser from being irradiated onto other portions than the joined portions, and can effectively block external light to solve a problem in which the electrode or the like provided inside is observed from the outside.

[0117] Reference Figure 10D and Figure 10E In the manufacturing method of the display apparatus according to the embodiments, a process of removing the solution layer SL can be further included after the process of joining the light emitting element ED and the electrodes E1 and E2. The solution layer SL can be removed by a cleaning material selected according to the properties of a solvent included in a solution forming the solution layer SL. In an embodiment, the solution layer SL can be formed of a solution including a water-soluble solvent, and removed by washing with water after the joining process. In another embodiment, the solution layer SL can be formed of a solution including an organic solvent, and removed by washing with ethanol or acetone after the joining process.

[0118] According to the embodiments of the present inventive concept, a problem in which incident external light can be transmitted through the transparent LED and reflected by the reflective electrode and thus a user can observe the internal configuration including the reflective electrode or the like can be prevented or substantially prevented, and accordingly, the reliability of the display apparatus can be improved.

[0119] While the present application has been described with reference to certain example embodiments thereof, a person of ordinary skill in the art, in light of the description contained herein will appreciate that various changes and modifications can be made thereto without departing from the spirit and scope of the application as set forth in the appended claims and equivalents thereof.

[0120] Therefore, the scope of the present inventive concept should not be limited or restricted by the foregoing description, but rather the widest scope permissible by the following claims and their equivalents.

Claims

1. A display device comprising: a base substrate, an electrode on the base substrate; a pixel-defining layer on the base substrate and covering a portion of the electrode, wherein an opening exposing a portion of the electrode other than the portion is defined in the pixel-defining layer; a light-emitting element on the base substrate and electrically connected to the electrode; and a solution layer between the base substrate and the light-emitting element, wherein the solution layer includes a light-blocking material, and wherein the light-emitting element and the solution layer are in the opening. 2.The display device according to claim 1, wherein the light-emitting element includes a contact portion contacting the electrode, and the solution layer surrounds the contact portion. 3.The display device according to claim 2, wherein the electrode includes a first electrode and a second electrode spaced apart from the first electrode, and the contact portion includes: a first contact portion connected to the first electrode; and a second contact portion connected to the second electrode.

4. The display device of claim 3, wherein, the light-emitting element further includes: a base layer; a first semiconductor layer on the base layer; a second semiconductor layer on the first semiconductor layer; a first element electrode on the second semiconductor layer and connected to the first contact portion; and a second element electrode on the first semiconductor layer and connected to the second contact portion. 5.The display device according to claim 4, wherein the light-emitting element further includes an element insulating layer covering at least a portion of the first element electrode and the second element electrode, and the solution layer is in contact with the first contact portion, the second contact portion, and the element insulating layer.

6. The display device of claim 1, wherein, the solution layer includes a water-soluble solvent and a sodium salt dissolved in the water-soluble solvent, wherein the sodium salt has a black color.

7. The display device of claim 1, wherein, the solution layer includes an organic solvent and a black organic pigment dispersed in the organic solvent. 8.A manufacturing method of a display device, the manufacturing method comprising: forming an electrode on a base substrate; forming a pixel-defining layer on the base substrate, the pixel-defining layer covering a portion of the electrode, wherein an opening exposing a portion of the electrode other than the portion is defined in the pixel-defining layer, in the opening, forming a solution layer by providing a solution including a light-blocking material on the electrode; transferring a light-emitting element such that the light-emitting element passes through the solution layer in the opening and is electrically connected to the electrode; and joining the light-emitting element to the electrode by applying light or heat to a portion where the light-emitting element is connected to the electrode. 9.The manufacturing method according to claim 8, wherein the light-emitting element includes a contact portion, and during the transferring the light-emitting element, the transferring is performed such that the contact portion contacts the electrode.

Images