DISPLAY DEVICE AND METHOD OF MANUFACTURING THE SAME

A display device includes a substrate including a display area and a peripheral area disposed outside the display area, a light-emitting element disposed on the display area of the substrate, and an encapsulation member disposed on the light-emitting element and including at least one inorganic encapsulation layer and at least one organic encapsulation layer. An organic encapsulation layer of the at least one organic encapsulation layer includes surface-enhanced Raman scattering (SERS) active nanoparticles.

CROSS-REFERENCE TO RELATED APPLICATION

BACKGROUND

One or more embodiments relate to a display device and a method of manufacturing the same.

2. Description of the Related Art

Display devices visually display data. Recently, display devices have been used in a greater variety of ways. In addition, display devices have become thinner and lighter in weight, and thus, their range of use has widened.

For example, in the case of an organic light-emitting display device, in order to manufacture a thin and light display device, an emission area may be encapsulated by using, instead of an encapsulation substrate formed of a glass material, a thin-film encapsulation layer including at least one inorganic encapsulation layer and at least one organic encapsulation layer.

The organic encapsulation layer may planarize an upper surface of a display area of the organic light-emitting display device by covering the display area and may prevent cracking of the inorganic encapsulation layer by covering a portion of a peripheral area of the organic light-emitting display device.

In the case where the organic encapsulation layer is coated using an inkjet method, there may be a need to check whether a material of the organic encapsulation layer discharged via an inkjet process has been disposed at a target location on the peripheral area.

SUMMARY

One or more embodiments allow monitoring of a disposition location of an organic encapsulation layer via Raman detection by adding surface-enhanced Raman scattering (SERS) active nanoparticles to an organic encapsulation layer. However, such a technical feature is an example, and one or more embodiments are not limited thereto.

According to one or more embodiments, a display device includes a substrate including a display area and a peripheral area disposed outside the display area, a light-emitting element disposed on the display area of the substrate, and an encapsulation member disposed on the light-emitting element and including at least one inorganic encapsulation layer and at least one organic encapsulation layer. An organic encapsulation layer of the at least one organic encapsulation layer includes surface-enhanced Raman scattering (SERS) active nanoparticles.

The SERS active nanoparticles may be metal nanoparticles on the surface of which a Raman label compound is adsorbed, wherein a size of each of the metal nanoparticles may be at least about 1 nm but not more than about 20 nm.

The metal nanoparticles may include gold (Au), silver (Ag), or copper (Cu).

The Raman label compound may include an aromatic ring.

The Raman label compound may include at least one of thiophenol, 4-Mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 4-mercaptophenylboronic acid, 4-mercaptobenzoic acid, or pyridine-4-thiol.

Based on a total weight of the organic encapsulation layer, a content of the SERS active nanoparticles may be greater than 0 wt % but not more than 5 wt %.

A viscosity of the organic encapsulation layer may range from 1 cP to 50 cP.

The at least one inorganic encapsulation layer may include a first inorganic encapsulation layer and a second inorganic encapsulation layer. The organic encapsulation layer may be disposed on the first inorganic encapsulation layer, and the second inorganic encapsulation layer may be disposed on the organic encapsulation layer.

The display device may further include a dam portion disposed on the peripheral area, wherein the first inorganic encapsulation layer and the second inorganic encapsulation layer may be in contact with each other on the dam portion.

The display device may further include a valley portion disposed on the peripheral area and disposed between the dam portion and the display area, wherein the organic encapsulation layer may overlap the valley portion.

The light-emitting element may include a pixel electrode, an emission layer on the pixel electrode, and an opposite electrode on the emission layer.

According to one or more embodiments, a display device includes a substrate, a light-emitting element disposed on the substrate and including a pixel electrode, an emission layer on the pixel electrode, and an opposite electrode on the emission layer, and an encapsulation member disposed on the light-emitting element. The encapsulation member includes a first inorganic encapsulation layer, an organic encapsulation layer on the first inorganic encapsulation layer, and a second inorganic encapsulation layer on the organic encapsulation layer. The organic encapsulation layer includes surface-enhanced Raman scattering (SERS) active nanoparticles in which metal nanoparticles are surface-treated with a Raman label compound, wherein the Raman label compound includes an aromatic ring.

A size of each of the metal nanoparticles may be 20 nm or less.

The metal nanoparticles may include gold (Au), silver (Ag), or copper (Cu).

The Raman label compound may include at least one of thiophenol, 4-Mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 4-mercaptophenylboronic acid, 4-mercaptobenzoic acid, or pyridine-4-thiol.

Based on a total weight of the organic encapsulation layer, a content of the SERS active nanoparticles may be greater than 0 wt % but not more than 5 wt %.

According to one or more embodiments, a method of manufacturing a display device includes forming a first inorganic encapsulation layer on a light-emitting element, forming an organic encapsulation layer on the first inorganic encapsulation layer, the organic encapsulation layer including surface-enhanced Raman scattering (SERS) active nanoparticles, testing a disposition location of the organic encapsulation layer by using Raman spectroscopy, and forming a second inorganic encapsulation layer on the organic encapsulation layer.

The SERS active nanoparticles may be formed by surface-treating metal nanoparticles with a Raman label compound, wherein a size of each of the metal nanoparticles may be 20 nm or less.

The Raman label compound may include an aromatic ring.

The Raman label compound may include at least one of thiophenol, 4-Mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 4-mercaptophenylboronic acid, 4-mercaptobenzoic acid, or pyridine-4-thiol.

DETAILED DESCRIPTION

As the present description allows for various changes and numerous embodiments, certain embodiments will be illustrated in the drawings and described in the written description. Effects and features of one or more embodiments and methods of accomplishing the same will become apparent from the following detailed description of the one or more embodiments, taken in conjunction with the accompanying drawings. However, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein.

While such terms as “first” and “second” may be used to describe various elements, such elements must not be limited to the above terms. The above terms are used only to distinguish one element from another.

The singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well unless the context clearly indicates otherwise.

It will be understood that the terms “include,” “comprise,” and “have” as used herein specify the presence of stated features or elements but do not preclude the addition of one or more other features or elements.

It will be further understood that, when a layer, region, or element is referred to as being on another layer, region, or element, it may be directly or indirectly on the other layer, region, or element. That is, for example, intervening layers, regions, or elements may be present.

Sizes of elements in the drawings may be exaggerated or reduced for convenience of explanation. For example, since sizes and thicknesses of elements in the drawings are arbitrarily illustrated for convenience of explanation, the following embodiments are not limited thereto.

When an embodiment may be implemented differently, a certain process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order.

FIG.1is a schematic plan view of a display device1according to an embodiment.

Referring toFIG.1, the display device1may display an image. The display device1may include a display area DA and a peripheral area PA. In an embodiment, the display area DA and the peripheral area PA may be defined on a substrate100. In other words, the substrate100may include the display area DA and the peripheral area PA.

The display device1may provide an image through a plurality of sub-pixels P disposed on the display area DA. Each of the sub-pixels P of the display device1is an area capable of emitting light of a certain color, and the display device1may display an image by using light emitted from the plurality of sub-pixels P. For example, the sub-pixel P may emit red, green, or blue light. As another example, the sub-pixel P may emit red, green, blue, or white light.

The peripheral area PA may be disposed outside the display area DA. For example, the peripheral area PA may at least partially surround the display area DA. In an embodiment, the peripheral area PA may entirely surround the display area DA. The peripheral area PA, which is an area where sub-pixels P are not disposed, may be an area where no image is provided.

A first dam portion DP1and a second dam portion DP2may be disposed on the peripheral area PA. The first dam portion DP1and the second dam portion DP2may surround the display area DA. The first dam portion DP1and the second dam portion DP2may be apart from each other. Although, in the present embodiment, the number of dam portions surrounding the display area DA is shown as two, one or more embodiments are not limited thereto, and the number may be variously changed to one or two or more. The first dam portion DP1and the second dam portion DP2may serve as a dam that blocks an organic material from flowing towards the edge of the substrate100when an organic encapsulation layer320(refer toFIG.3) constituting, e.g., included in, an encapsulation member300(refer toFIG.3) is formed via an inkjet process, and thus, may prevent an edge tail from being formed at the edge of the substrate100by the organic encapsulation layer320.

As shown inFIG.1, the display area DA may have a polygonal shape including a quadrilateral shape. For example, the display area DA may have a rectangular shape having a horizontal length greater than a vertical length, a rectangular shape having a horizontal length less than a vertical length, or a square shape. Alternatively, the display area DA may have various shapes, such as an oval shape or a circular shape.

The display device1may be included in a mobile phone, a television, a billboard, a monitor, a tablet personal computer (PC), a notebook computer, etc.

The display device1is a device for displaying an image, and may be a liquid crystal display, an electrophoretic display, an organic light-emitting display, an inorganic light-emitting display, a field emission display, a surface-conduction electron-emitter display, a plasma display, a cathode ray display, or the like.

FIGS.2A and2Bare examples of an equivalent circuit diagram of the sub-pixel P included in the display device1according to an embodiment.

Paying particular attention toFIG.2A, each sub-pixel P may include a pixel circuit PC connected to a scan line SL and a data line DL and a light-emitting element LED connected to the pixel circuit PC. For example, the light-emitting element LED may be an organic light-emitting diode.

The pixel circuit PC may include a driving thin-film transistor T1, a switching thin-film transistor T2, and a storage capacitor Cst.

The switching thin-film transistor T2is configured to transfer a data signal Dm input through the data line DL to the driving thin-film transistor T1according to a scan signal Sn input through the scan line SL.

The storage capacitor Cst is connected to the switching thin-film transistor T2and a driving voltage line PL and stores a voltage corresponding to a difference between a voltage received from the switching thin-film transistor T2and a first power voltage ELVDD (or referred to as a driving voltage) supplied to the driving voltage line PL.

The driving thin-film transistor T1is connected to the driving voltage line PL and the storage capacitor Cst, and may be configured to control a driving current flowing through the light-emitting element LED from the driving voltage line PL, in response to a voltage value stored in the storage capacitor Cst. The light-emitting element LED may emit light having certain brightness according to the driving current.

AlthoughFIG.2Ashows a case where the pixel circuit PC includes two thin-film transistors T1, T2and one storage capacitor Cst, one or more embodiments are not limited thereto.

Referring toFIG.2B, the pixel circuit PC may include the driving and switching thin-film transistors T1and T2, a compensation thin-film transistor T3, a first initialization thin-film transistor T4, a first emission control thin-film transistor T5, a second emission control thin-film transistor T6, and a second initialization thin-film transistor T7.

AlthoughFIG.2Bshows each sub-pixel P including signal lines, for example, a first scan line SLn, a second scan line SLn−1, an emission control line EL, and the data line DL, an initialization voltage line VL, and the driving voltage line PL, one or more embodiments are not limited thereto. In an embodiment, at least one of the signal lines, for example, the first scan line SLn, the second scan line SLn−1, the emission control line EL, and the data line DL, and/or the initialization voltage line VL may be shared with neighboring sub-pixels P.

A drain electrode of the driving thin-film transistor T1may be electrically connected to the light-emitting element LED via the second emission control thin-film transistor T6. The driving thin-film transistor T1is configured to receive the data signal Dm according to a switching operation of the switching thin-film transistor T2and supply a driving current to the light-emitting element LED.

A gate electrode of the switching thin-film transistor T2is connected to the first scan line SLn, and a source electrode thereof is connected to the data line DL. A drain electrode of the switching thin-film transistor T2may be connected to a source electrode of the driving thin-film transistor T1and may also be connected to the driving voltage line PL via the first emission control thin-film transistor T5.

The switching thin-film transistor T2is turned on according to a first scan signal Sn received through the first scan line SLn and is configured to perform a switching operation for transferring the data signal Dm transmitted through the data line DL to the source electrode of the driving thin-film transistor T1.

A gate electrode of the compensation thin-film transistor T3may be connected to the first scan line SLn. A source electrode of the compensation thin-film transistor T3may be connected to the drain electrode of the driving thin-film transistor T1and may also be connected to a pixel electrode of the light-emitting element LED via the second emission control thin-film transistor T6. A drain electrode of the compensation thin-film transistor T3may be connected to one electrode of the storage capacitor Cst, a source electrode of the first initialization thin-film transistor T4, and a gate electrode of the driving thin-film transistor T1. The compensation thin-film transistor T3is turned on according to the first scan signal Sn received through the first scan line SLn and is configured to diode-connect the driving thin-film transistor T1by connecting the gate electrode and the drain electrode of the driving thin-film transistor T1to each other.

A gate electrode of the first initialization thin-film transistor T4may be connected to the second scan line SLn−1 (previous scan line). A drain electrode of the first initialization thin-film transistor T4may be connected to the initialization voltage line VL. The source electrode of the first initialization thin-film transistor T4may be connected to the one electrode of the storage capacitor Cst, the drain electrode of the compensation thin-film transistor T3, and the gate electrode of the driving thin-film transistor T1. The first initialization thin-film transistor T4may be turned on according to a second scan signal Sn−1 received through the second scan line SLn−1 and be configured to perform an initialization operation for initializing a voltage of the gate electrode of the driving thin-film transistor T1by transferring an initialization voltage VINT to the gate electrode of the driving thin-film transistor T1.

A gate electrode of the first emission control thin-film transistor T5may be connected to the emission control line EL. A source electrode of the first emission control thin-film transistor T5may be connected to the driving voltage line PL. A drain electrode of the first emission control thin-film transistor T5may be connected to the source electrode of the driving thin-film transistor T1and the drain electrode of the switching thin-film transistor T2.

A gate electrode of the second emission control thin-film transistor T6may be connected to the emission control line EL. A source electrode of the second emission control thin-film transistor T6may be connected to the drain electrode of the driving thin-film transistor T1and the source electrode of the compensation thin-film transistor T3. A drain electrode of the second emission control thin-film transistor T6may be electrically connected to the pixel electrode of the light-emitting element LED. The first emission control thin-film transistor T5and the second emission control thin-film transistor T6are simultaneously turned on according to an emission control signal En received through the emission control line EL, and thus, the first power voltage ELVDD is transferred to the light-emitting element LED and a driving current flows through the light-emitting element LED.

A gate electrode of the second initialization thin-film transistor T7may be connected to the second scan line SLn−1. A source electrode of the second initialization thin-film transistor T7may be connected to the pixel electrode of the light-emitting element LED. A drain electrode of the second initialization thin-film transistor T7may be connected to the initialization voltage line VL. The second initialization thin-film transistor T7may be turned on according to the second scan signal Sn−1 received through the second scan line SLn−1 and be configured to initialize the pixel electrode of the light-emitting element LED.

AlthoughFIG.2Bshows a case where the first initialization thin-film transistor T4and the second initialization thin-film transistor T7are connected to the second scan line SLn−1, one or more embodiments are not limited thereto. In an embodiment, the first initialization thin-film transistor T4may be connected to the second scan line SLn−1, which is a previous scan line, to operate according to the second scan signal Sn−1, and the second initialization thin-film transistor T7may be connected to a separate signal line (e.g., a next scan line) to operate according to a signal transmitted to the corresponding scan line.

The other electrode of the storage capacitor Cst may be connected to the driving voltage line PL. The one electrode of the storage capacitor Cst may be connected to the gate electrode of the driving thin-film transistor T1, the drain electrode of the compensation thin-film transistor T3, and the source electrode of the first initialization thin-film transistor T4.

An opposite electrode (e.g., a cathode) of the light-emitting element LED receives a second power voltage ELVSS (or referred to as a common power voltage). The light-emitting element LED receives a driving current from the driving thin-film transistor T1and emits light.

The pixel circuit PC is not limited to the numbers of thin-film transistors and storage capacitors and the circuit design described with reference toFIGS.2A and2B, and the numbers of thin-film transistors and storage capacitors and the circuit design may be variously changed.

FIG.3is a schematic cross-sectional view of the display device1according to an embodiment, taken along a line I-I′ ofFIG.1.FIG.4is a schematic enlarged view of the organic encapsulation layer320of the display device1.

Referring toFIGS.3and4, the display device1may include the substrate100, a pixel circuit layer PCL, the light-emitting element LED, and the encapsulation member300. The display device1may further include a valley portion VP, the first dam portion DP1, and the second dam portion DP2. The valley portion VP may include a first valley portion VP1and a second valley portion VP2.

The substrate100may include glass. In an embodiment, the substrate100may include polymer resin, such as polyethersulfone, polyarylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyimide, polycarbonate, cellulose triacetate, cellulose acetate propionate, etc. In an embodiment, the substrate100may have a multi-layer structure including a base layer and a barrier layer (not shown), the base layer including the above polymer resin. Hereinafter, a case where the substrate100includes glass will be mainly described in detail.

The pixel circuit layer PCL may be disposed on the substrate100. The pixel circuit layer PCL may include a buffer layer101, a first inorganic insulating layer103, a second inorganic insulating layer105, a third inorganic insulating layer107, the pixel circuit PC including a first thin-film transistor TFT1, a second thin-film transistor TFT2, and a third thin-film transistor TFT3.

The pixel circuit PC may include at least one first thin-film transistor TFT1and the storage capacitor Cst. The first thin-film transistor TFT1may be disposed on the display area DA. The first thin-film transistor TFT1may be, but is not limited to, the driving thin-film transistor T1of the pixel circuit PC described with reference toFIG.2Aor the second emission control thin-film transistor T6of the pixel circuit PC described with reference toFIG.2B.

The second thin-film transistor TFT2and the third thin-film transistor TFT3may be disposed on the peripheral area PA. Each of the second thin-film transistor TFT2and the third thin-film transistor TFT3may be a thin-film transistor of a driving circuit. For example, the second thin-film transistor TFT2may be a thin-film transistor of a scan driving circuit, and the third thin-film transistor TFT3may be a thin-film transistor of an emission control driving circuit.

Each of the first thin-film transistor TFT1, the second thin-film transistor TFT2, and the third thin-film transistor TFT3may include a semiconductor layer Act, a gate electrode GE, a source electrode SE, and a drain electrode DE.

The buffer layer101may be disposed on the substrate100to planarize an upper surface of the substrate100and block impurities from flowing in from the substrate100. The buffer layer101may include an inorganic insulating material such as silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiOxNy). The buffer layer101may include a single-layer or multi-layer structure including the above inorganic insulating material.

The semiconductor layer Act may be disposed on the buffer layer101. The semiconductor layer Act may include an oxide semiconductor and/or a silicon semiconductor. When the semiconductor layer Act includes an oxide semiconductor, the semiconductor layer Act may include, for example, oxide of at least one material selected from the group including indium (In), gallium (Ga), tin (Sn), zirconium (Zr), vanadium (V), hafnium (Hf), cadmium (Cd), germanium (Ge), chromium (Cr), titanium (Ti), and zinc (Zn). For example, the semiconductor layer Act may be an InSnZnO (ITZO) semiconductor layer, an InGaZnO (IGZO) semiconductor layer, or the like. When the semiconductor layer Act includes a silicon semiconductor, the semiconductor layer Act may include, for example, amorphous silicon or low temperature poly-silicon (LTPS).

The gate electrode GE may be disposed over the semiconductor layer Act with the first inorganic insulating layer103therebetween. The gate electrode GE may overlap a channel region of the semiconductor layer Act. The gate electrode GE may include a low-resistance metal material. For example, the gate electrode GE may have a single-layer or multi-layer structure including one or more metals selected from among 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 gate electrode GE may be connected to a gate line configured to apply an electrical signal to the gate electrode GE.

The first inorganic insulating layer103may be disposed on the buffer layer101. The first inorganic insulating layer103may be disposed between the semiconductor layer Act and the gate electrode GE. The first inorganic insulating layer103may include, for example, an inorganic insulating material such as silicon oxide (SiO2), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZnOx, which may include ZnO and/or ZnO2).

The second inorganic insulating layer105may be disposed on the first inorganic insulating layer103. The second inorganic insulating layer105may cover the gate electrode GE. In a similar way to the first inorganic insulating layer103, the second inorganic insulating layer105may include an inorganic insulating material such as silicon oxide (SiO2), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZnOx, which may include ZnO and/or ZnO2).

An upper electrode CE2of the storage capacitor Cst may be disposed on the second inorganic insulating layer105. In an embodiment, the upper electrode CE2may overlap the gate electrode GE. In this regard, the gate electrode GE and the upper electrode CE2overlapping each other with the second inorganic insulating layer105therebetween may constitute the storage capacitor Cst. That is, the gate electrode GE may serve as a lower electrode CE1of the storage capacitor Cst. As described above, the storage capacitor Cst and the first thin-film transistor TFT1may overlap each other. In an embodiment, the storage capacitor Cst and the first thin-film transistor TFT1may not overlap each other.

The third inorganic insulating layer107may be disposed on the second inorganic insulating layer105. The third inorganic insulating layer107may cover the upper electrode CE2. The third inorganic insulating layer107may include silicon oxide (SiO2), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZnOx, which may include ZnO and/or ZnO2). The third inorganic insulating layer107may have a single-layer or multi-layer structure including the above inorganic insulating material.

The source electrode SE and the drain electrode DE may each be disposed on the third inorganic insulating layer107. The source electrode SE and the drain electrode DE may be electrically connected to the semiconductor layer Act through contact holes formed in the first inorganic insulating layer103, the second inorganic insulating layer105, and the third inorganic insulating layer107. The source electrode SE and the drain electrode DE may include a highly conductive material. At least one of the source electrode SE and the drain electrode DE may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), or titanium (Ti), and may have a multi-layer or single-layer structure including the above material. In an embodiment, at least one of the source electrode SE and the drain electrode DE may have a multi-layer structure of Ti/Al/Ti.

In an embodiment, the display device1may further include a power voltage line11on the pixel circuit layer PCL. The power voltage line11may be disposed on the third inorganic insulating layer107. The power voltage line11may be disposed on the peripheral area PA. The power voltage line11may be a wire configured to transmit various signals and/or voltages to be provided to the pixel circuit PC. For example, the power voltage line11may be a common power voltage line configured to provide the second power voltage ELVSS (refer toFIGS.2A and2B) to each of the sub-pixels P (refer toFIGS.2A and2B).

The display device1may further include at least one planarization layer disposed on the pixel circuit layer PCL. In an embodiment, the display device1may include a first planarization layer110and a second planarization layer120disposed on the pixel circuit layer PCL.

The first planarization layer110may be disposed on the pixel circuit layer PCL. The first planarization layer110may cover the pixel circuit PC. The first planarization layer110may be disposed on the third inorganic insulating layer107. The first planarization layer110may be disposed on the source electrode SE and the drain electrode DE. The first planarization layer110may be disposed on the first thin-film transistor TFT1in the display area DA and may be disposed on the second and third thin-film transistors TFT2and TFT3in the peripheral area PA. The second planarization layer120may be disposed on the first planarization layer110while covering a connection electrode CM described below.

Each of the first planarization layer110and the second planarization layer120may include an organic insulating layer. Each of the first planarization layer110and the second planarization layer120may include an organic material. Each of the first planarization layer110and the second planarization layer120may include an organic insulating material such as a general commercial polymer, such as polymethylmethacrylate (PMMA) or polystyrene (PS), a polymer derivative having a phenol-based group, an acryl-based polymer, an imide-based polymer, an aryl ether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, a vinyl alcohol-based polymer, and a blend thereof. The first planarization layer110and the second planarization layer120may planarize an upper surface of the pixel circuit PC, thereby planarizing a surface on which the light-emitting element LED is to be positioned.

In an embodiment, the display device1may further include the connection electrode CM disposed on the first planarization layer110in the display area DA. The connection electrode CM may be disposed between the first planarization layer110and the second planarization layer120. The connection electrode CM may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), etc., and may have a multi-layer or single-layer structure including the above material. In an embodiment, the connection electrode CM may have a multi-layer structure of Ti/Al/Ti. The second planarization layer120may be disposed on the first planarization layer110while covering the connection electrode CM.

The light-emitting element LED may be disposed over the pixel circuit layer PCL in the display area DA. The light-emitting element LED may be electrically connected to the pixel circuit PC disposed between the substrate100and the light-emitting element LED in a direction (e.g., a direction z) perpendicular to the substrate100. The light-emitting element LED may be disposed on the second planarization layer120. The light-emitting element LED may emit red, green, or blue light, or may emit red, green, blue, or white light. A stacked structure of a pixel electrode210, an intermediate layer220, and an opposite electrode230may constitute one light-emitting element LED.

The light-emitting element LED may be an organic light-emitting diode including an organic emission layer. Alternatively, the light-emitting element LED may be an inorganic light-emitting diode including an inorganic emission layer. The light-emitting diode may have a micro-scale or nano-scale size. For example, the light-emitting diode may be a micro light-emitting diode. Alternatively, the light-emitting diode may be a nanorod light-emitting diode. The nanorod light-emitting diode may include gallium nitride (GaN). In an embodiment, a color conversion layer may be disposed on the nanorod light-emitting diode. The color conversion layer may include quantum dots. Alternatively, the light-emitting diode may be a quantum dot light-emitting diode including a quantum dot emission layer.

The pixel electrode210may be disposed on the second planarization layer120. The pixel electrode210may be electrically connected to the connection electrode CM through a contact hole in the second planarization layer120. In an embodiment, the pixel electrode210may include conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnOx, which may include ZnO and/or ZnO2), indium oxide (In2O3), indium gallium oxide (IGO), or aluminum zinc oxide (AZO). In an embodiment, the pixel electrode210may include a reflective layer including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), or a compound thereof. In an embodiment, the pixel electrode210may further include a layer including ITO, IZO, ZnO, or In2O3on/under the above reflective layer. For example, the pixel electrode210may have a multi-layer structure of ITO/Ag/ITO.

A pixel-defining layer130including an opening130OP exposing a central portion of the pixel electrode210may be disposed on the pixel electrode210. The pixel-defining layer130may include an organic insulating material and/or an inorganic insulating material. One opening130OP in the pixel-defining layer130may correspond to one light-emitting element LED and may define one emission area. An area exposed by the opening130OP of the pixel-defining layer130may be defined as an emission area.

The intermediate layer220may be disposed on the pixel-defining layer130. The intermediate layer220may include an emission layer disposed in the opening130OP of the pixel-defining layer130. The emission layer may include a high-molecular weight or low-molecular weight organic material emitting light of a certain color.

Although not shown inFIG.3, a first functional layer and a second functional layer may be further disposed under and on the emission layer, respectively. The first functional layer may include, for example, a hole transport layer (HTL), or an HTL and a hole injection layer (HIL). The second functional layer is an element disposed on the emission layer and is optional. The second functional layer may include an electron transport layer (ETL) and/or an electron injection layer (EIL). In an embodiment, like the opposite electrode230described below, the first functional layer and/or the second functional layer may be common layers entirely covering the substrate100.

The opposite electrode230may include a conductive material having a low work function. For example, the opposite electrode230may include a (semi) transparent layer including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), or an alloy thereof. Alternatively, the opposite electrode230may further include a layer, such as ITO, IZO, ZnO, or In2O3, on a (semi) transparent layer including the above material.

In some embodiments, a capping layer (not shown) may be further disposed on the opposite electrode230. The capping layer may include lithium fluoride (LiF), an inorganic material, and/or an organic material.

The encapsulation member300may cover the light-emitting element LED. The encapsulation member300may be disposed on the opposite electrode230. In an embodiment, the encapsulation member300may be disposed on the display area DA.

In an embodiment, the encapsulation member300includes at least one inorganic encapsulation layer and at least one organic encapsulation layer, and in an embodiment, the encapsulation member300is shown as including a first inorganic encapsulation layer310, the organic encapsulation layer320, and a second inorganic encapsulation layer330sequentially stacked on one another.

The first inorganic encapsulation layer310and the second inorganic encapsulation layer330may be entirely disposed on the display area DA and the peripheral area PA. The first inorganic encapsulation layer310and the second inorganic encapsulation layer330may be apart from each other in the display area DA. The first inorganic encapsulation layer310and the second inorganic encapsulation layer330may be apart from each other in some regions of the peripheral area PA and may be in contact with each other in the other regions. The first inorganic encapsulation layer310and the second inorganic encapsulation layer330may be in contact with each other over the first dam portion DP1and/or the second dam portion DP2.

The first inorganic encapsulation layer310and the second inorganic encapsulation layer330may include an inorganic material. The first inorganic encapsulation layer310and the second inorganic encapsulation layer330may include, for example, one or more inorganic materials among aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), zinc oxide (ZnOx, which may include ZnO and/or ZnO2), silicon oxide (SiO2), silicon nitride (SiNx), and silicon oxynitride (SiON).

The organic encapsulation layer320may be disposed on the display area DA. The organic encapsulation layer320may extend from the display area DA to the peripheral area PA. The organic encapsulation layer320may fill the first valley portion VP1and the second valley portion VP2. The organic encapsulation layer320may overlap the first valley portion VP1and the second valley portion VP2. The organic encapsulation layer320may not overlap at least the first dam portion DP1. The organic encapsulation layer320may not overlap the second dam portion DP2. The organic encapsulation layer320may extend from the display area DA to the inside of the second dam portion DP2. The organic encapsulation layer320may overlap the second thin-film transistor TFT2and/or the third thin-film transistor TFT3.

In the case where the organic encapsulation layer320is formed using an inkjet method, when an inkjet discharge location of an organic material is biased toward an end of the substrate100, a material of an organic layer may overflow to the outside of the first dam portion DP1. When the inkjet discharge location of the organic material is biased toward the display area DA, the first and second inorganic encapsulation layers310and330may be cracked due to the lack of an organic material filled in the peripheral area PA. Accordingly, there is a need to monitor whether the organic material is accurately discharged to a target location and is safely disposed on the target location and to adjust a discharge location of an organic material.

As shown inFIG.4, the organic encapsulation layer320may include an organic material321and surface-enhanced Raman scattering (SERS) active nanoparticles400. The organic encapsulation layer320may be formed by adding the SERS active nanoparticles400into the organic material321. The viscosity of the organic encapsulation layer320may range from about 1 cP to about 50 cP. Because the organic encapsulation layer320includes the SERS active nanoparticles400, whether an organic encapsulation layer320is disposed at a target location may be tested by Raman spectroscopy or Raman detection after the organic encapsulation layer320is formed. Because layers disposed below the organic encapsulation layer320, for example, the pixel-defining layer130, the opposite electrode230of the light-emitting element LED, and/or the capping layer on the opposite electrode230, do not include SERS active nanoparticles, a position of an end where the organic encapsulation layer320is formed may be identified by distinguishing between the organic encapsulation layer320and the layers disposed below the organic encapsulation layer320.

A SERS active nanoparticle400may be a nanoparticle in which a Raman label compound420is adsorbed or bound onto a surface of a metal nanoparticle410. The SERS active nanoparticle400may be a material obtained by surface-treating the metal nanoparticle410with the Raman label compound420. In the present description, the Raman label compound420may refer to a small-molecule compound among materials that cause a Raman signal in vibrational, rotational, and other low-frequency modes of a material. The Raman signal is recognized as a structural fingerprint for a molecule and is used as a probe for detecting a target material in a sample.

The content of the SERS active nanoparticles400may be greater than 0 wt % but not more than about 5 wt %, based on a total weight of the organic encapsulation layer320. When the content of the SERS active nanoparticles400is greater than 5 wt %, the transmittance of the organic encapsulation layer320may decrease.

A size of the metal nanoparticle410may be, for example, at least about 1 nm but not more than about 20 nm. A size of the metal nanoparticle410may be, for example, at least about 5 nm but not more than about 20 nm. When a size of the metal nanoparticle410is less than 1 nm, the Raman label compound420may not be well adsorbed onto the metal nanoparticle410. When a size of the metal nanoparticle410is greater than 20 nm, the transmittance of the organic encapsulation layer320may decrease. The metal nanoparticle410may include, for example, a metal particle such as gold (Au), silver (Ag), or copper (Cu).

When the content of the SERS active nanoparticles400is greater than 0 wt % but not more than about 5 wt %, and a size of the SERS active nanoparticle400or the metal nanoparticle410included in the SERS active nanoparticle400is 20 nm or less, the transmittance of the organic encapsulation layer320may be about 97% or greater. Accordingly, even when the organic encapsulation layer320includes the SERS active nanoparticles400, display quality of the display device1may not deteriorate.

In an embodiment, the Raman label compound420may include an aromatic ring. When the SERS active nanoparticle400includes the Raman label compound420including an aromatic ring, it may be easy to distinguish from the layers disposed below the organic encapsulation layer320. The Raman label compound420may include, for example, at least one of thiophenol, 4-Mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 4-mercaptophenylboronic acid, 4-mercaptobenzoic acid, or pyridine-4-thiol.

The display device1may include the first dam portion DP1and the second dam portion DP2. The first dam portion DP1and the second dam portion DP2may be disposed on the peripheral area PA. The first dam portion DP1and the second dam portion DP2may at least partially overlap the power voltage line11. The first dam portion DP1may be apart from the organic encapsulation layer320in a first direction (e.g., a direction x or a direction y). The first dam portion DP1may not overlap the organic encapsulation layer320. In other words, the first dam portion DP1may not be covered by the organic encapsulation layer320. The second dam portion DP2may be disposed between the first dam portion DP1and the organic encapsulation layer320. The second dam portion DP2may be disposed between the first dam portion DP1and the first valley portion VP1.

The first dam portion DP1may include a first insulating pattern110Pa, a second insulating pattern120Pa, a third insulating pattern130Pa, and a fourth insulating pattern140Pa sequentially stacked on one another. The first insulating pattern110Pa may be disposed on the third inorganic insulating layer107. The second insulating pattern120Pa may be disposed on the first insulating pattern110Pa. The third insulating pattern130Pa may be disposed on the second insulating pattern120Pa. The fourth insulating pattern140Pa may be disposed on the third insulating pattern130Pa.

The first insulating pattern110Pa may be formed during the same process operation as the first planarization layer110and may include the same material as the first planarization layer110. The second insulating pattern120Pa may be formed during the same process operation as the second planarization layer120and may include the same material as the second planarization layer120. The third insulating pattern130Pa may be formed during the same process operation as the pixel-defining layer130and may include the same material as the pixel-defining layer130. The fourth insulating pattern140Pa may be formed during the same process operation as a spacer (not shown) disposed on the pixel-defining layer130in the display area DA and may include the same material as the spacer.

The second dam portion DP2may include a fifth insulating pattern120Pb, a sixth insulating pattern130Pb, and a seventh insulating pattern140Pb sequentially stacked on one another. The fifth insulating pattern120Pb may be disposed over the third inorganic insulating layer107. The sixth insulating pattern130Pb may be disposed on the fifth insulating pattern120Pb. The seventh insulating pattern140Pb may be disposed on the sixth insulating pattern130Pb.

The fifth insulating pattern120Pb may be formed during the same process operation as the second planarization layer120and/or the second insulating pattern120Pa and may include the same material as the second planarization layer120and/or the second insulating pattern120Pa. The sixth insulating pattern130Pb may be formed during the same process operation as the pixel-defining layer130and/or the third insulating pattern130Pa and may include the same material as the pixel-defining layer130and/or the third insulating pattern130Pa. The seventh insulating pattern140Pb may be formed during the same process operation as a spacer (not shown) disposed on the pixel-defining layer130in the display area DA and/or the fourth insulating pattern140Pa and may include the same material as the spacer (not shown) and/or the fourth insulating pattern140Pa.

The number and height of insulating patterns included in the first dam portion DP1and the second dam portion DP2are not limited to those shown and may vary depending on embodiments.

In the peripheral area PA, the display device1may further include an eighth insulating pattern130hdisposed on the second planarization layer120. In an embodiment, the eighth insulating pattern130hmay be formed during the same process operation as the pixel-defining layer130and may have a height relatively smaller than that of the pixel-defining layer130due to a subsequent process. In an embodiment, the eighth insulating pattern130hmay be an insulating pattern disposed on the second planarization layer120through a separate process from the pixel-defining layer130of the display area DA.

The display device1may include the first valley portion VP1including an opening OP1in the first planarization layer110and an opening OP2in the second planarization layer120. The first valley portion VP1may be disposed on the peripheral area PA. The first valley portion VP1may be disposed between the first dam portion DP1and the display area DA. The first valley portion VP1may be disposed between the second dam portion DP2and the display area DA. Portions of the first planarization layer110and the second planarization layer120in the peripheral area PA may be separated from portions thereof in the display area DA by the first valley portion VP1. The first valley portion VP1may prevent or reduce moisture or foreign materials generated in an area disposed outside from penetrating into the display area DA through the first planarization layer110and/or the second planarization layer120.

The power voltage line11may be disposed between the first insulating pattern110Pa of the first dam portion DP1and the first planarization layer110. In an embodiment, the edge of the power voltage line11may be covered by the first insulating pattern110Pa of the first dam portion DP1and the first planarization layer110, and a central portion of the power voltage line11may not be covered by the first dam portion DP1and the first planarization layer110to have an exposed upper surface.

A conductive layer CLa may be disposed on the power voltage line11. In an embodiment, the conductive layer CLa may include a first conductive layer CL1and a second conductive layer CL2on the first conductive layer CL1.

The first conductive layer CL1may be disposed on an upper surface of the power voltage line11and may be disposed on a side surface of the first insulating pattern110Pa and a side surface of the first planarization layer110. In other words, the first conductive layer CL1may be disposed on the upper surface of the power voltage line11and may extend to the side surface of the first insulating pattern110Pa and the side surface of the first planarization layer110. A portion of the first conductive layer CL1may be disposed on an upper surface of the first insulating pattern110Pa and an upper surface of the first planarization layer110.

The second conductive layer CL2may be disposed on the second valley portion VP2described below. The second conductive layer CL2may be disposed on an upper surface of the first conductive layer CL1and may be disposed on a side surface of the fifth insulating pattern120Pb and a side surface of the second planarization layer120. In other words, the second conductive layer CL2may be disposed on the upper surface of the first conductive layer CL1and may extend to the side surface of the fifth insulating pattern120Pb and the side surface of the second planarization layer120. A portion of the second conductive layer CL2may be disposed on an upper surface of the fifth insulating pattern120Pb and an upper surface of the second planarization layer120. The first inorganic encapsulation layer310may be disposed on the second conductive layer CL2.

A conductive pattern layer CPL may be disposed on the first valley portion VP1. The conductive pattern layer CPL may be in contact with an upper surface of the third inorganic insulating layer107and may extend to a side wall of the first planarization layer110, a side wall of the second planarization layer120, and the upper surface of the second planarization layer120. The first inorganic encapsulation layer310may be disposed over the conductive pattern layer CPL.

The display device1may further include the second valley portion VP2disposed between the second dam portion DP2and the first valley portion VP1. The second valley portion VP2may be disposed on the peripheral area PA. The second valley portion VP2may be disposed between the first dam portion DP1and the display area DA. The second valley portion VP2may be disposed between the second dam portion DP2and the display area DA. The second valley portion VP2may be an area where the second dam portion DP2and the first and second planarization layers110and120are apart from each other and thus the encapsulation member300is prevented from overflowing to the outside of the second dam portion DP2.

FIG.5is a flowchart of a method of manufacturing of a display device, according to an embodiment. In an embodiment, the display device1described with reference toFIGS.3and4may be formed according to the method of manufacturing a display device, described with reference toFIG.5.

Referring toFIGS.3to5, a method of manufacturing the display device1may include an operation of forming the first inorganic encapsulation layer310on the light-emitting element LED in an operation S1, an operation of forming, on the first inorganic encapsulation layer310, the organic encapsulation layer320including the SERS active nanoparticles400in an operation S2, an operation of testing a disposition location of the organic encapsulation layer320in an operation S3, and an operation of forming the second inorganic encapsulation layer330on the organic encapsulation layer320in an operation S4.

Before the first inorganic encapsulation layer310is formed, the pixel circuit layer PCL including the pixel circuit PC may be formed on the substrate100, and the light-emitting element LED over the pixel circuit layer PCL may be formed. In an embodiment, the first dam portion DP1and/or the second dam portion DP2disposed on the peripheral area PA may be formed on the pixel circuit layer PCL. The first dam portion DP1and the second dam portion DP2may be disposed on the periphery of the substrate100.

The first inorganic encapsulation layer310may be entirely formed over the substrate100. That is, the first inorganic encapsulation layer310may be entirely formed in the display area DA where the light-emitting element LED is disposed and the peripheral area PA where the light-emitting element LED is not disposed.

The first inorganic encapsulation layer310may be formed on the light-emitting element LED by a deposition process. For example, the first inorganic encapsulation layer310may be formed by chemical vapor deposition (CVD).

The first inorganic encapsulation layer310may include an inorganic material. The first inorganic encapsulation layer310may include, for example, one or more inorganic materials among aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), zinc oxide (ZnOx, which may include ZnO and/or ZnO2), silicon oxide (SiO2), silicon nitride (SiNx), and silicon oxynitride (SiON).

The organic encapsulation layer320may be formed on the first inorganic encapsulation layer310. The organic encapsulation layer320may be formed to cover the entire display area DA. The organic encapsulation layer320may be formed to cover only a portion of the peripheral area PA. For example, the organic encapsulation layer320may be formed not to overlap the first dam portion DP1. For example, the organic encapsulation layer320may be formed not to overlap the second dam portion DP2. For example, the organic encapsulation layer320may be formed not to overflow to the outside of the first dam portion DP1and/or the second dam portion DP2.

The organic encapsulation layer320may include a material obtained by adding the SERS active nanoparticles400into an organic material. For example, the organic encapsulation layer320may include a material obtained by adding the SERS active nanoparticles400into a composition including a thermosetting or photocurable monomer. The monomer for forming the organic encapsulation layer320may be, for example, an acryl monomer or an epoxy monomer. The organic encapsulation layer320may be formed, for example, by performing an inkjet process. Based on a total weight of the organic encapsulation layer320, the content of the SERS active nanoparticles400may be greater than 0 wt % but not more than 5 wt %.

The SERS active nanoparticles400added into the organic material may be formed through surface treatment for adsorbing or binding the Raman label compound420onto the metal nanoparticle410. A size of the metal nanoparticle410may be, for example, at least about 1 nm but not more than about 20 nm. A size of the metal nanoparticle410may be, for example, at least about 5 nm but not more than about 20 nm. The metal nanoparticle410may include, for example, a metal particle such as gold (Au), silver (Ag), or copper (Cu). The Raman label compound420adsorbed onto the metal nanoparticle410may be a compound including an aromatic ring. For example, the Raman label compound420adsorbed onto the metal nanoparticle410may include, for example, at least one of thiophenol, 4-Mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 4-mercaptophenylboronic acid, 4-mercaptobenzoic acid, or pyridine-4-thiol.

The organic encapsulation layer320includes a composition including a photocurable monomer or a thermosetting monomer, and accordingly, may include a polymer-based material formed by curing an organic material. The organic material321included in the organic encapsulation layer320may be a polymer-based material formed by curing a photocurable monomer or a thermosetting monomer. For example, the organic material321may include acryl-based resin (e.g., polymethyl methacrylate, polyacrylic acid, etc.), epoxy-based resin, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene sulfonate, polyoxymethylene, polyarylate, hexamethyldisiloxane, polyimide, polyethylene, or any combination thereof.

After the organic encapsulation layer320is formed, an operation of testing a disposition location of the organic encapsulation layer320may be performed. Because the organic encapsulation layer320includes the SERS active nanoparticles400, a disposition location of the organic encapsulation layer320may be analyzed by Raman spectroscopy or Raman detection. Unlike the organic encapsulation layer320, layers disposed below the organic encapsulation layer320(e.g., the pixel-defining layer130, the opposite electrode230, and the capping layer on the opposite electrode230) do not include the SERS active nanoparticles400, and accordingly, the organic encapsulation layer320may be identified distinguished from the layers below by using Raman spectroscopy or Raman detection. For example, it may be tested using Raman spectroscopy or Raman detection whether the organic encapsulation layer320covers light-emitting elements LED of the display area DA and has not overflowed to the outside of the first dam portion DP1and/or the second dam portion DP2.

In the present description, Raman spectroscopy or Raman detection may be a method in which Raman scattering, which occurs when a material with a Raman label compound scatters involving loss or gain of molecular vibrational energy, is detected through a Raman spectrometer when a material is irradiated with a light source. Raman spectroscopy may be a method in which a SERS spectrum formed for a target material by Raman scattering is measured and analyzed. Raman spectroscopy may include an operation of irradiating a target material with a light source and an operation of detecting Raman scattering (or a Raman signal) from the target material.

The second inorganic encapsulation layer330may be entirely formed over the substrate100. That is, the second inorganic encapsulation layer330may be entirely formed in the display area DA where the light-emitting element LED is disposed and the peripheral area PA where the light-emitting element LED is not disposed.

The second inorganic encapsulation layer330may be formed on the organic encapsulation layer320and the first inorganic encapsulation layer310by using a deposition process. For example, the second inorganic encapsulation layer330may be formed by chemical vapor deposition (CVD).

The second inorganic encapsulation layer330may include an inorganic material. The second inorganic encapsulation layer330may include, for example, one or more inorganic materials among aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), zinc oxide (ZnOx, which may include ZnO and/or ZnO2), silicon oxide (SiO2), silicon nitride (SiNx), and silicon oxynitride (SiON).

According to one or more of the above embodiments, a disposition location of a material for forming an organic encapsulation layer may be monitored via Raman detection by adding SERS active nanoparticles to an organic encapsulation layer. It may be easily checked whether the organic encapsulation layer has been formed at a target location, and thus, the reliability of a display device may be increased. However, such an effect is an example, and one or more embodiments are not limited thereto.