DISPLAY APPARATUS

Embodiments provide a display apparatus that includes a first substrate, a first light-emitting diode, a second light-emitting diode, and a third light-emitting diode, an encapsulation layer covering the first light-emitting diode, the second light-emitting diode, and the third light-emitting diode, a bank layer on the encapsulation layer, the bank layer including a first bank opening corresponding to the first light-emitting diode, a second bank opening corresponding to the second light-emitting diode, and a third bank opening corresponding to the third light-emitting diode, a first quantum dot layer disposed in the first bank, a second quantum dot layer disposed in the second bank opening, a first organic capping layer disposed in the second bank opening and covering the second quantum dot layer, and an inorganic capping layer covering the bank layer, the first quantum dot layer, and the second quantum dot layer.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and benefits of Korean Patent Application No. 10-2022-0104276 under 35 U.S.C. § 119, filed on Aug. 19, 2022, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

Embodiments relate to a display apparatus on which a high-quality image may be displayed.

2. Description of the Related Art

In general, a display apparatus includes pixels. For a full-color display apparatus, the pixels may emit light of different colors. To this end, at least some of the pixels of the display apparatus includes a color conversion unit. Accordingly, light of a first color generated by an emission unit of a pixel is converted into light of a second color by passing through a corresponding color conversion unit, and is emitted to the outside.

SUMMARY

In a display apparatus of the related art, when a color conversion unit is exposed to light and/or oxygen during a display manufacturing process, light conversion efficiency may decrease.

Embodiments include a display apparatus on which a high-quality image may be displayed. However, the embodiments are only examples, and the scope of the disclosure is not limited thereto.

According to embodiments, a display apparatus may include a first substrate; a first light-emitting diode, a second light-emitting diode, and a third light-emitting diode, which are disposed on the first substrate and emit light of a wavelength belonging to a first wavelength band; an encapsulation layer covering the first light-emitting diode, the second light-emitting diode and the third light-emitting diode; a bank layer on the encapsulation layer, the bank layer including a first bank opening corresponding to the first light-emitting diode, a second bank opening corresponding to the second light-emitting diode, and a third bank opening corresponding to the third light-emitting diode; a first quantum dot layer disposed in the first bank opening and which converts light of a wavelength belonging to the first wavelength band to light of a wavelength belonging to a second wavelength band; a second quantum dot layer disposed in the second bank opening and which converts light of a wavelength belonging to the first wavelength band to light of a wavelength belonging to a third wavelength band; a first organic capping layer disposed in the second bank opening and covering the second quantum dot layer; and an inorganic capping layer covering the bank layer, the first quantum dot layer, and the first organic capping layer.

In an embodiment, the bank layer may further include a first bank layer on the encapsulation layer and having a lyophilic surface, and a second bank layer on the first bank layer and having a lyophobic surface.

In an embodiment, a fixed point at which an upper surface of the first organic capping layer contacts a sidewall of the second bank opening may coincide with or may be adjacent to a point at which an interface between the first bank layer and the second bank layer contacts the sidewall of the second bank opening.

In an embodiment, the second quantum dot layer may have a concave shape in which a thickness of a central portion is less than a thickness of a peripheral portion adjacent to a sidewall of the second bank opening.

In an embodiment, in the first organic capping layer, a thickness of a central portion may be equal to a thickness of a peripheral portion adjacent to the sidewall of the second bank opening.

In an embodiment, the first organic capping layer may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to the sidewall of the second bank opening.

In an embodiment, the second quantum dot layer may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to a sidewall of the second bank opening, and in the first organic capping layer, a thickness of a central portion may be equal to a thickness of a peripheral portion.

In an embodiment, a thickness of the first organic capping layer may be in a range of about 0.1 μm to about 3 μm.

In an embodiment, the first wavelength band may be in a range of about 450 nm to about 495 nm, and the third wavelength band may be in a range of about 495 nm to about 570 nm.

In an embodiment, the display apparatus may further include a second organic capping layer disposed in the first bank opening and covering the first quantum dot layer.

In an embodiment, the display apparatus may further include a second substrate over the first substrate with the bank layer therebetween, and a color filter layer disposed on a lower surface of the second substrate in a direction toward the first substrate, wherein the color filter layer may include a first filter opening, a second filter opening, and a third filter opening, which respectively overlap the first light-emitting diode, the second light-emitting diode, and the third light-emitting diode, when viewed from a direction perpendicular to the first substrate.

In an embodiment, the display apparatus may further include a low-refractive index layer contacting a lower surface of the color filter layer in the direction toward the first substrate.

In an embodiment, the display apparatus may further include a filler between the inorganic capping layer and the low-refractive index layer.

According to embodiments, a display apparatus may include a second substrate; a color filter layer on the second substrate and including a first filter opening, a second filter opening, and a third filter opening; a low-refractive index layer on the color filter layer; a bank layer on the low-refractive index layer, the bank layer including a first bank opening corresponding to the first filter opening, a second bank opening corresponding to the second filter opening, and a third bank opening corresponding to the third filter opening; a first quantum dot layer disposed in the first bank opening and which converts light of a wavelength belonging to a first wavelength band into light of a wavelength belonging to a second wavelength band; a second quantum dot layer disposed in the second bank opening and which converts light of a wavelength belonging to the first wavelength band to light of a wavelength belonging to a third wavelength band; a first organic capping layer disposed in the second bank opening and covering the second quantum dot layer; and an inorganic capping layer covering the bank layer, the first quantum dot layer, and the first organic capping layer.

In an embodiment, the bank layer may further include a first bank layer on the low-refractive index layer and having a lyophilic surface, and a second bank layer on the first bank layer and having a lyophobic surface.

In an embodiment, a fixed point at which an upper surface of the first organic capping layer contacts a sidewall of the second bank opening may coincide with or may be adjacent to a point at which an interface between the first bank layer and the second bank layer contacts the sidewall of the second bank opening.

In an embodiment, the second quantum dot layer may have a concave shape in which a thickness of a central portion is less than a thickness of a peripheral portion adjacent to a sidewall of the second bank opening.

In an embodiment, in the first organic capping layer, a thickness of a central portion may be equal to a thickness of a peripheral portion adjacent to the sidewall of the second bank opening.

In an embodiment, the first organic capping layer may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to the sidewall of the second bank opening.

In an embodiment, the second quantum dot layer may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to a sidewall of the second bank opening, and in the first organic capping layer, a thickness of a central portion may be equal to a thickness of a peripheral portion.

In an embodiment, the display apparatus may further include a second organic capping layer disposed in the first bank opening and covering the first quantum dot layer.

In an embodiment, the display apparatus may further include a first substrate under the second substrate with the bank layer therebetween; a first light-emitting diode, a second light-emitting diode, and a third light-emitting diode, which are disposed on the first substrate and emit light of a wavelength belonging to the first wavelength band; and an encapsulation layer covering the first light-emitting diode, the second light-emitting diode and the third light-emitting diode.

In an embodiment, the display apparatus may further include a filler between the encapsulation layer and the inorganic capping layer.

According to embodiments, a display apparatus may include a first substrate; a first light-emitting diode, a second light-emitting diode, and a third light-emitting diode, which are disposed on the first substrate and emit light of a wavelength belonging to a first wavelength band; an encapsulation layer covering the first light-emitting diode, the second light-emitting diode, and the third light-emitting diode; a bank layer on the encapsulation layer, the bank layer including a first bank opening corresponding to the first light-emitting diode, a second bank opening corresponding to the second light-emitting diode, and a third bank opening corresponding to the third light-emitting diode; a first quantum dot layer disposed in the first bank opening and which converts light of a wavelength belonging to the first wavelength band to light of a wavelength belonging to a second wavelength band; a second quantum dot layer disposed in the second bank opening and which converts light of a wavelength belonging to the first wavelength band to light of a wavelength belonging to a third wavelength band; a first organic capping layer disposed in the second bank opening and covering the second quantum dot layer; an inorganic capping layer covering the bank layer, the first quantum dot layer, and the first organic capping layer; an organic low-refractive index layer on the inorganic capping layer and filling the first bank opening, the second bank opening, and the third bank opening; an inorganic protective layer on the inorganic low-refractive index layer; and a color filter layer directly contacting the inorganic protective layer, wherein the color filter layer may include a first filter opening, a second filter opening, and a third filter opening, which respectively overlap the first light-emitting diode, the second light-emitting diode, and the third light-emitting diode, when viewed from a direction perpendicular to the first substrate.

These and/or other aspects will become apparent and more readily appreciated from the accompanying drawings, the claims, and the detailed description of the disclosure.

It is to be understood that the embodiments above are described in a generic and explanatory sense only and not for the purpose of limitation, and the disclosure is not limited to the embodiments described above.

DETAILED DESCRIPTION OF THE EMBODIMENTS

It will be understood that the terms “connected to” or “coupled to” may refer to a physical, electrical and/or fluid connection or coupling, with or without intervening elements.

In the specification and the claims, the term “at least one of” is intended to include the meaning of “at least one selected from the group consisting of” for the purpose of its meaning and interpretation. For example, “at least one of A, B, and C” may be understood to mean A only, B only, C only, or any combination of two or more of A, B, and C, such as ABC, ACC, BC, or CC. When preceding a list of elements, the term, “at least one of,” modifies the entire list of elements and does not modify the individual elements of the list.

In the specification, the terms “x-axis”, “y-axis”, and “z-axis” are not limited to three axes in an orthogonal coordinate system (e.g., a Cartesian coordinate system), and may be interpreted in a broader sense than the aforementioned three axes in an orthogonal coordinate system. For example, the x-axis, y-axis, and z-axis may describe axes that are orthogonal to each other, or may describe axes that are in different directions that are not orthogonal to each other.

FIG.1is a schematic perspective view of a display apparatus1according to an embodiment.

Referring toFIG.1, the display apparatus1may include a display area DA and a non-display area NDA outside the display area DA. The display apparatus1may provide an image through a two-dimensional array of sub-pixels arranged on an x-y plane. The sub-pixels may include a first sub-pixel, a second sub-pixel, and a third sub-pixel, and hereinafter, for convenience of explanation, a case in which the first sub-pixel is a red sub-pixel Pr, the second sub-pixel is a green sub-pixel Pg, and the third sub-pixel is a blue sub-pixel Pb is described.

The red sub-pixel Pr, the green sub-pixel Pg, and the blue sub-pixel Pb are areas in which red, green, and blue light may be respectively emitted, and the display apparatus1may provide an image by using light emitted from the sub-pixels.

Each of the red sub-pixel Pr, the green sub-pixel Pg, and the blue sub-pixel Pb may have a polygonal shape when viewed from a direction (e.g., a z-axis direction) perpendicular to an upper surface of the display apparatus1. InFIG.1, each of the red sub-pixel Pr, the green sub-pixel Pg, and the blue sub-pixel Pb has a quadrilateral shape when viewed from the direction (e.g., a z-axis direction) perpendicular to the upper surface of the display apparatus1. However, the disclosure is not limited thereto. For example, each of the red sub-pixel Pr, the green sub-pixel Pg, and the blue sub-pixel Pb may have a circular or an elliptical shape when viewed from the direction (e.g., a z-axis direction) perpendicular to the upper surface of the display apparatus1. A shape of each of the red sub-pixel Pr, the green sub-pixel Pg, and the blue sub-pixel Pb when viewed from the direction (e.g., a z-axis direction) perpendicular to the upper surface of the display apparatus1may be defined by a first color filter layer810, a second color filter layer820, and/or a third color filter layer830, which will be described below.

The non-display area NDA, in which no image is provided, may entirely surround the display area DA. In the non-display area NDA, a driver or a main voltage line, which are configured to provide electrical signals or power to sub-pixel circuits, may be arranged. The non-display area NDA may include a pad, which is an area to which an electronic element or a printed circuit board may be electrically connected.

The display area DA may have a polygonal shape, including a quadrangle, as shown inFIG.1. 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. In other embodiments, the display area DA may have various shapes, such as an ellipse or a circle.

FIG.2is a schematic cross-sectional view illustrating each sub-pixel of the display apparatus1according to an embodiment.

Referring toFIG.2, the display apparatus1may include a circuit layer200on a first substrate100. The circuit layer200may include first to third sub-pixel circuits PC1, PC2, and PC3, and the first to third sub-pixel circuits PC1, PC2, and PC3may be electrically connected to first to third light-emitting diodes LED1, LED2, and LED3of a light-emitting diode layer300, respectively.

Each of the first to third light-emitting diodes LED1, LED2, and LED3may be an organic light-emitting diode including an organic material. In another embodiment, each of the first to third light-emitting diodes LED1, LED2, and LED3may be an inorganic light-emitting diode including an inorganic material. The inorganic light-emitting diode may include a PN junction diode including inorganic semiconductor-based materials. When a voltage is applied to the PN junction diode in a forward direction, holes and electrons may be injected thereinto, and energy generated by recombination of the holes and the electrons may be converted into light energy to emit light of a certain color. The inorganic light-emitting diode described above may have a width of several to several hundred micrometers or several to several hundred nanometers. In embodiments, each of the first to third light-emitting diodes LED1, LED2, and LED3may be a light-emitting diode including quantum dots. As described above, an emission layer of each of the first to third light-emitting diodes LED1, LED2, and LED3may include an organic material, an inorganic material, quantum dots, an organic material with quantum dots, or an inorganic material with quantum dots.

The first to third light-emitting diodes LED1, LED2, and LED3may emit light of a same color. For example, light (e.g., blue light Lb) emitted by the first to third light-emitting diodes LED1, LED2, and LED3may pass through a color conversion-transmissive layer600and an encapsulation layer400on the light-emitting diode layer300.

The color conversion-transmissive layer600may include optical units that transmit light (e.g., blue light Lb) emitted from the light-emitting diode layer300with or without color conversion. For example, the color conversion-transmissive layer600may include color conversion units and a transmissive unit, wherein the color conversion units convert light (e.g., blue light Lb) emitted from the light-emitting diode layer300into light of another color, and the transmissive unit transmits light (e.g., blue light Lb) emitted from the light-emitting diode layer300without color conversion. The color conversion-transmissive layer600may include a first quantum dot layer610corresponding to the red sub-pixel Pr, a second quantum dot layer620corresponding to the green sub-pixel Pg, and a transmissive layer630corresponding to the blue sub-pixel Pb. The first quantum dot layer610may convert the blue light Lb into red light Lr, and the second quantum dot layer620may convert the blue light Lb into green light Lg. The transmissive layer630may transmit the blue light Lb without conversion.

The blue light Lb emitted from the light-emitting diode layer300may be light of a wavelength belonging to a first wavelength band. For example, the first wavelength band may be in a range of about 450 nm to about 495 nm. The red light Lr into which the blue light Lb is converted by the first quantum dot layer610may be light of a wavelength belonging to a second wavelength band. For example, the second wavelength band may be in a range of about 625 nm to about 780 nm. The green light Lg into which the blue light Lb is converted by the second quantum dot layer620may be light of a wavelength belonging to a third wavelength band. For example, the third wavelength band may be in a range of about 495 nm to about 570 nm. However, the disclosure is not limited thereto, and a wavelength band to which a wavelength of light emitted from the light-emitting diode layer300belongs and a wavelength band to which a wavelength of the light after conversion belongs may be modified.

A color filter layer800may be disposed on the color conversion-transmissive layer600. The color filter layer800may include the first to third color filter layers810,820, and830, which are of different colors. For example, the first color filter layer810may be a red color filter, the second color filter layer820may be a green color filter, and the third color filter layer830may be a blue color filter.

Each of the light color-converted by the color conversion-transmissive layer600and the light transmitted by the color conversion-transmissive layer600may have improved color purity by passing through the first to third color filter layers810,820, and830. The color filter layer800may prevent, or minimize, reflection and recognition of external light (e.g., light incident toward the display apparatus1from the outside of the display apparatus1) by a user.

A transmissive base layer may be included on the color filter layer800. In an embodiment, the transmissive base layer, which is a second substrate900, may be integrated such that the color conversion-transmissive layer600and the encapsulation layer400face each other after the color filter layer800and the color conversion-transmissive layer600are formed on the second substrate800. In another embodiment, the color conversion-transmissive layer600may be integrated such that the color filter layer800and the color conversion-transmissive layer600face each other after forming the color conversion-transmissive layer600on the encapsulation layer400and forming the color filter layer800on the second substrate900.

The second substrate900may include glass or a transmissive organic material. For example, the second substrate900may include a transmissive organic material, such as acryl-based resin. In some embodiments, another optical film, e.g., an anti-reflection (AR) film or the like, may be disposed on the second substrate900.

The display apparatus1having the structure described above may include electronic devices capable of displaying a moving image or a still image, such as televisions, advertisement boards, cinema screens, monitors, tablet personal computers (PC), and laptops.

FIG.3is a schematic diagram illustrating each optical unit of the color conversion-transmissive layer ofFIG.2.

Referring toFIG.3, the first quantum dot layer610may convert blue light Lb incident thereon into red light Lr. As shown inFIG.3, the first quantum dot layer610may include a first photosensitive polymer1151and first quantum dots1152and first scattering particles1153dispersed in the first photosensitive polymer1151.

The first quantum dots1152may be excited by the blue light Lb and may isotropically emit the red light Lr, which has a longer wavelength than the blue light Lb. The first photosensitive polymer1151may be an organic material having light transmission properties. The first scattering particles1153may scatter the blue light Lb that is not absorbed by the first scattering particles1153to excite more first quantum dots1152, thereby improving color conversion efficiency. The first scattering particles1153may scatter incident light in multiple directions regardless of an incident angle, without substantially converting a wavelength of the light. Accordingly, the first scattering particles1153may improve side visibility of the display apparatus. For example, the first scattering particles1153may be titanium oxide (TiO2) or metal particles. The first quantum dots1152may be selected from among Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group III-VI semiconductor compounds, Group I-III-VI semiconductor compounds, Group IV-VI semiconductor compounds, or any combinations thereof.

Examples of Group I-III-VI semiconductor compounds may include: a ternary compound, such as AgInS, AgInS2, CuInS, CuInS2, CuGaO2, AgGaO2, or AgAlO2; or any mixture thereof.

Examples of Group IV elements or compounds may include: a single-element material, such as Si or Ge; a binary compound, such as SiC or SiGe; or any mixture thereof.

Each element included in a multi-element compound, such as a binary compound, a ternary compound, and a quaternary compound, may be present in particles in a uniform concentration or in a non-uniform concentration.

A quantum dot may have a single structure or a core-shell structure, in which a concentration of each element included in the corresponding quantum dot is uniform. For example, in case that the quantum dot has a core-shell structure a material included in the core and a material included in the shell may be different from each other. The shell of the quantum dot may serve as a protective layer for maintaining semiconductor properties by preventing chemical denaturation of the core and/or may serve as a charging layer for imparting electrophoretic properties to the quantum dot. The shell may include a layer or layers. An interface between the core and the shell may have a concentration gradient in which the concentration of elements in the shell decreases toward the core.

Examples of the shell of the quantum dot may include a metal oxide, a non-metal oxide, a semiconductor compound, or any combinations thereof. Examples of the metal oxide or the non-metal oxide may include: a binary compound, such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, or NiO; a ternary compound, such as MgAl2O4, CoFe2O4, NiFe2O4, or CoMn2O4; or any mixture thereof. Examples of the semiconductor compound may include Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group III-VI semiconductor compounds, Group I-III-VI semiconductor compounds, Group IV-VI semiconductor compounds, as described above, or any mixture thereof. For example, the semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or any mixture thereof.

The quantum dot may have a full width of half maximum (FWHM) of an emission wavelength spectrum of less than or equal to about 45 nm, For example, the quantum dot may have an FWHM of the emission wavelength spectrum of less than or equal to about 40 nm. For another example, the quantum dot may have an FWHM of the emission wavelength spectrum of less than or equal to about 30 nm. Color purity or color reproducibility may be improved in this range. Light emitted from the quantum dots may be emitted in all directions, so that an optical viewing angle may be improved.

The quantum dots may be in the form of spherical, pyramidal, multi-arm or cubic, nanoparticles, nanowires, nanofibers, or nanoplatelet particles.

Because an energy bandgap may be adjusted by adjusting sizes of the quantum dots, light of various wavelength bands may be obtained from a quantum dot emission layer. Accordingly, by using quantum dots of different sizes, a light-emitting element emitting light of various wavelengths may be implemented. The sizes of the quantum dots may be selected such that red, green, and/or blue light may be emitted. The size of the quantum dots may be configured such that light of various colors combine with each other to emit white light.

The second quantum dot layer620may convert the blue light Lb incident thereon into the green light Lg. As shown inFIG.3, the second quantum dot layer620may include a second photosensitive polymer1161and second quantum dots1162and second scattering particles1163dispersed in the second photosensitive polymer1161.

The second quantum dots1162may be excited by the blue light Lb and may isotropically emit the green light Lg having a greater wavelength than the blue light Lb. The second photosensitive polymer1161may be an organic material having light transmission properties.

The second scattering particles1163may scatter the blue light Lb that is not absorbed by the second quantum dots1162to excite more second quantum dots1162, thereby improving color conversion efficiency. For example, the second scattering particles1163may be TiO2or metal particles. The second quantum dots1162may be selected from among Group III-V compounds, Group III-VI compounds, Group II-VI compounds, Group I-III-VI compounds, or any mixture thereof. In an embodiment, the second quantum dots1162may include InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof. Because a quantum confinement effect occurs in a size relatively greater than a general size of the quantum dots, the second quantum dots1162may reduce a quantization period in which the blue light Lb is not absorbed and thus have high light conversion efficiency.

In some embodiments, the first quantum dots1152may include a same material as a material of the second quantum dots1162. Sizes of the first quantum dots1152may be greater than sizes of the second quantum dots1162.

The transmissive layer630may transmit the blue light Lb without converting the blue light Lb incident to the transmissive layer630. As shown inFIG.3, the transmissive layer630may include a third photosensitive polymer1171, in which third scattering particles1173are dispersed. The third photosensitive polymer1171may be an organic material having transmissivity, such as silicon resin and epoxy resin, and may include a same material as materials of the first and second photosensitive polymers1151and1161. The third scattering particles1173may scatter and emit the blue light Lb, and may include a same material as materials of the first and second scattering particles1153and1163.

FIG.4is an equivalent circuit diagram illustrating a light-emitting diode LED and a sub-pixel circuit PC electrically connected to the light-emitting diode LED, included in the display apparatus according to an embodiment. The sub-pixel circuit PC shown inFIG.4may correspond to each of the first to third sub-pixel circuits PC1, PC2, and PC3described above with reference toFIG.2, and the light-emitting diode LED ofFIG.4may correspond to each of the first to third light-emitting diodes LED1, LED2, and LED3described above with reference toFIG.2.

Referring toFIG.4, the light-emitting diode LED, e.g., a pixel electrode (e.g., an anode) of the light-emitting diode LED, may be connected to the sub-pixel circuit PC, and an opposite electrode (e.g., a cathode) of the light-emitting diode LED may be electrically connected to a main common voltage line to be described later, and receive a common voltage ELVSS. The light-emitting diode LED may emit light of a luminance corresponding to an amount of current received from the sub-pixel circuit PC.

The sub-pixel circuit PC may control an amount of current flowing from a driving voltage ELVDD to the common voltage ELVSS via the light-emitting diode LED, in response to a data signal. The sub-pixel circuit PC may include a first transistor M1, a second transistor M2, a third transistor M3, and a storage capacitor Cst.

Each of the first transistor M1, the second transistor M2, and the third transistor M3may be an oxide semiconductor transistor including a semiconductor layer formed of an oxide semiconductor, or may be a silicon semiconductor including a semiconductor layer formed of polysilicon. Depending on a type of a transistor, a first electrode of the transistor may be one of a source electrode and a drain electrode, and a second electrode of the transistor may be the other one of the source electrode and drain electrode.

The first electrode of the first transistor M1may be connected to a driving voltage line PL configured to apply the driving voltage ELVDD, and the second electrode may be connected to the pixel electrode of the light-emitting diode LED. A gate electrode of the first transistor M1may be connected to a first node N1. The first transistor M1may control an amount of current flowing from the driving voltage ELVDD to the light-emitting diode LED, in response to a voltage of the first node N1.

The second transistor M2may be a switching transistor. A first electrode of the second transistor M2may be connected to a data line DL, and a second electrode may be connected to the first node N1. A gate electrode of the second transistor M2may be connected to a scan line SL. The second transistor M2may be turned on when a scan signal is received via the scan line SL and may electrically connect the data line DL to the first node N1.

The third transistor M3may be an initialization transistor and/or a sensing transistor. A first electrode of the third transistor M3may be connected to a second node N2, and a second electrode may be connected to a sensing line SEL. A gate electrode of the third transistor M3may be connected to a control line CL.

The storage capacitor Cst may be connected between the first node N1and the second node N2. For example, a first capacitor electrode of the storage capacitor Cst may be connected to the gate electrode of the first transistor M1, and a second capacitor electrode of the storage capacitor Cst may be connected to the pixel electrode of the light-emitting diode LED.

InFIG.4, the first transistor M1, the second transistor M2, and the third transistor M3are n-channel metal-oxide-semiconductor field-effect transistors (NMOS). However, the disclosure is not limited thereto. For example, at least one of the first transistor M1, the second transistor M2, and the third transistor M3may be formed as a p-channel metal-oxide-semiconductor field-effect transistor (PMOS).

InFIG.4, three transistors are shown. However, the disclosure is not limited thereto. The sub-pixel circuit PC may include four or more transistors.

FIG.5is a schematic cross-sectional view illustrating the display apparatus, taken along line I-I′ inFIG.1, andFIG.6is an enlarged schematic cross-sectional view illustrating region II of the display apparatus shown inFIG.5.

Referring toFIG.5, the circuit layer200may be disposed on a substrate100, the light-emitting diode layer300including the first to third light-emitting diodes LED1, LED2, and LED3may be disposed on the circuit layer200, and the light-emitting diode layer300may be sealed by the encapsulation layer400. A bank layer500including first to third bank openings501,502, and503respectively corresponding to the first to third light-emitting diodes LED1, LED2, and LED3may be disposed on the encapsulation layer400, and the color conversion-transmissive layer600including the first quantum dot layer610, the second quantum dot layer620, and the transmissive layer630may be disposed in the first to third bank openings501,502, and503. The second substrate900may be located on the color conversion-transmissive layer600. The color filter layer800including first to third filter openings801,802, and803respectively corresponding to the first to third light-emitting diodes LED1, LED2, and LED3may be disposed on a lower surface of the second substrate900in a direction toward the first substrate100(e.g., a −z direction). A low-refractive index layer700may be arranged between the color filter layer800and the first quantum dot layer610, the second quantum dot layer620, and the transmissive layer630.

The first substrate100may include glass, metal, or polymer resin. For example, the first substrate100may include polymer resin, such as polyethersulfone, polyacrylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, or cellulose acetate propionate. However, the first substrate100may have a multi-layer structure including two layers and a barrier layer therebetween, wherein the two layers include the polymer resin described above, and the barrier layer includes an inorganic material (such as silicon oxide, silicon nitride, silicon oxynitride, or the like), and various modifications may be made.

A buffer layer201may be disposed on the first substrate100. The buffer layer201may prevent impurities from permeating into a semiconductor layer Act of a thin-film transistor TFT from the first substrate100. The buffer layer201may include an inorganic insulating material, such as silicon oxide, silicon nitride, and/or silicon oxynitride.

The circuit layer200including the first to third sub-pixel circuits PC1, PC2, and PC3may be disposed on the buffer layer201. Each of the first to third sub-pixel circuits PC1, PC2, and PC3may include the thin-film transistor TFT and a capacitor Cap. The thin-film transistor TFT and the capacitor Cap shown inFIG.5may correspond to the first transistor M1and the storage capacitor Cst shown inFIG.4, respectively.

The semiconductor layer Act of the thin-film transistor TFT may be disposed on the buffer layer201. The semiconductor layer Act may include an oxide semiconductor. The oxide semiconductor may include indium gallium zinc oxide (IGZO), zinc tin oxide (ZTO), indium zinc oxide (IZO), or the like. In another embodiment, the semiconductor layer Act may include polysilicon, amorphous silicon, or an organic semiconductor. The semiconductor layer Act may include a channel area and conductive areas at opposite sides of the channel area, wherein the channel area overlaps a gate electrode GE, and the conductive areas are doped with impurities or are conductively disposed. Any of the conductive areas may be a source area, and the other one may correspond to a drain area.

The gate electrode GE may include various conductive materials and may have various layered structures, such as an Mo layer and an Al layer. The gate electrode GE may have a layered structure of an Mo layer, an Al layer, and another Mo layer. In another embodiment, the gate electrode GE may include a TiNxlayer, an Al layer, and/or a Ti layer.

A source electrode SE and a drain electrode DE may also include various conductive materials and may have various layered structures, such as a Ti layer, an Al layer, and/or a Cu layer. Each of the source electrode SE may have a layered structure of a Ti layer, an Al layer, and another Ti layer.

InFIG.5, the thin-film transistor TFT includes both the source electrode SE and the drain electrode DE. However, the disclosure is not limited thereto. For example, a source area of the semiconductor layer Act of the thin-film transistor TFT may be integrally provided as a single body with a drain area of a semiconductor layer of another thin-film transistor, and the thin-film transistor TFT may not include the source electrode SE. The source electrode SE and/or the drain electrode DE may be part of a line.

To ensure insulation between the semiconductor layer Act and the gate electrode GE, a gate insulating layer203may include an inorganic material, such as silicon oxide, silicon nitride, and/or silicon oxynitride, may be located between the semiconductor layer Act and the gate electrode GE. Further, an interlayer insulating layer205may include an inorganic material, such as silicon oxide, silicon nitride, and/or silicon oxynitride, may be disposed on the gate electrode GE, and the source electrode SE and the drain electrode DE may be disposed on the interlayer insulating layer205. An insulating layer including an inorganic material, as described above may be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD). This may also apply to embodiments to be described below and modifications thereof.

The capacitor Cap may include a first capacitor electrode Cap1and a second capacitor electrode Cap2. The first capacitor electrode Cap1may be located on the gate insulating layer203, and the second capacitor electrode Cap2may be located on the interlayer insulating layer205.

The first capacitor electrode Cap1may include various conductive materials, and may have various layered structures, such as an Mo layer and an Al layer. The first capacitor electrode Cap1may have a layered structure of an Mo layer, an Al layer, and another Mo layer. In another embodiment, the first capacitor electrode Cap1may include a TiNxlayer, an Al layer, and/or a Ti layer.

The second capacitor electrode Cap2may also include various conductive materials and may have various layered structures, for example, a Ti layer, an Al layer, and/or a Cu layer. The second capacitor electrode Cap2may have a layered structure of a Ti layer, an Al layer, and another Ti layer.

A planarization layer207may be formed on the thin-film transistor TFT and the capacitor Cap. The planarization layer207may have an approximately flat surface so that first to third pixel electrodes311,312, and313or the like may be located on a flat surface. The planarization layer207may include an organic insulating material, such as acrylic, benzocyclobutene (BCB), polyimide, and/or hexamethyldisiloxane (HMDSO). InFIG.5, the planarization layer207includes a single layer. However, the planarization layer207may include layers, and various modifications may be made.

A first light-emitting diode LED1including a first pixel electrode311, an opposite electrode330, and an intermediate layer320may be located on the planarization layer207, wherein the intermediate layer320is located between first pixel electrode311and the opposite electrode330and includes an emission layer. As shown inFIG.5, the first pixel electrode311may contact any of the source electrode SE and the drain electrode DE of the thin-film transistor TFT via a contact hole defined in the planarization layer207or the like, and be electrically connected to the first sub-pixel circuit PC1. The first pixel electrode311may include a transmissive conductive layer including a transmissive conductive oxide, such as ITO, In2O3, and IZO, and a reflective layer including a metal, such as Al or Ag. For example, the first pixel electrode311may have a three-layer structure of an ITO layer, an Ag layer, and another ITO layer.

The second light-emitting diode LED2may include a second pixel electrode312, the opposite electrode330, and the intermediate layer320located between the second pixel electrode312and the opposite electrode330and including an emission layer. Similarly, the third light-emitting diode LED3may include a third pixel electrode313, the opposite electrode330, and the intermediate layer320located between the third pixel electrode313and the opposite electrode330and including an emission layer. The second pixel electrode312may contact any of the source electrode SE and the drain electrode DE of the thin-film transistor TFT via a contact hole defined in the planarization layer207or the like, and be electrically connected to the second sub-pixel circuit PC2. The third pixel electrode313may contact any of the source electrode SE and the drain electrode DE of the thin-film transistor TFT via a contact hole defined in the planarization layer207or the like, and be electrically connected to the third sub-pixel circuit PC3. Descriptions of the first pixel electrode311provided above are applicable to the second pixel electrode312and the third pixel electrode313.

As described above, the intermediate layer320including the emission layer may be located not only on the first pixel electrode311of the first light-emitting diode LED1, but also on the second pixel electrode312of the second light-emitting diode LED2and the third pixel electrode313of the third light-emitting diode LED3. The intermediate layer320described above may be provided as a single body across the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313. However, the intermediate layer320may be patterned and located on the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313. The intermediate layer320may include a hole injection layer, a hole transport layer, and/or an electron transport layer in addition to the emission layer, and the layers included in the intermediate layer320described above may be integrally provided as a single body over the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313. However, some of the layers included in the intermediate layer320may be patterned and located to correspond to the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313. The emission layer included in the intermediate layer320may emit light of a wavelength belonging to a first wavelength band. The first wavelength band may be, for example, in a range of about 450 nm to about 495 nm, and light emitted by the first to third light-emitting diodes LED1, LED2, and LED3may be the blue light Lb.

However, the intermediate layer320may include multiple layers instead of a single layer. For example, the intermediate layer320may have a stacked structure of a first emission layer and a second emission layer with a charge generation layer located therebetween. The hole transport layer or the electron transport layer may be located between the first emission layer and the charge generation layer and between the second emission layer and the charge generation layer.

The opposite electrode330on the intermediate layer320may also be integrally provided as a single body across the first pixel electrode311to the third pixel electrode313. The opposite electrode330may include a transmissive conductive layer including ITO, In2O3, or IZO, and may include a semi-transmissive layer including a metal, such as Al, Li, Mg, Yb, or Ag. For example, the opposite electrode330may be a semi-transmissive layer including MgAg, AgYb, Yb/MgAg, or Li/MgAg.

A pixel-defining layer PDL may be disposed on the planarization layer207. The pixel-defining layer PDL may include pixel openings respectively corresponding to the first to third pixel electrodes311,312, and313. For example, the pixel-defining layer PDL may include a first pixel opening OP1exposing a central portion of the first pixel electrode311, a second pixel opening OP2exposing a central portion of the second pixel electrode312, and a third pixel opening OP3exposing a central portion of the third pixel electrode313, the first pixel opening OP1covering an edge of each of the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313. As shown inFIG.5, the pixel-defining layer PDL may increase a distance between the opposite electrode330and an edge of each of the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313, thereby preventing an arc or the like from occurring at the edges of the first pixel electrode311, the second pixel electrode312, and the third pixel electrode313. The pixel-defining layer PDL described above may include an organic material, such as polyimide or HMDSO.

Organic light-emitting elements including the first pixel electrode311, the second pixel electrode312, the third pixel electrode313, the intermediate layer320, which includes an emission layer, and the opposite electrode330, may be readily deteriorated by moisture or oxygen. Accordingly, to protect the organic light-emitting elements from external moisture or oxygen, the display apparatus may include the encapsulation layer400covering the organic light-emitting elements.

The encapsulation layer400may include at least one inorganic encapsulation layer and at least one organic encapsulation layer. For example, the encapsulation layer400may include a first inorganic encapsulation layer410, a second inorganic encapsulation layer430, and an organic encapsulation layer420therebetween.

Each of the first inorganic encapsulation layer410and the second inorganic encapsulation layer430may include at least one inorganic insulating material, such as silicon oxide (SiO2), silicon nitride (SiNx), silicon oxynitride (SiOxNy), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZnO2), and may be formed by CVD or the like. The organic encapsulation layer420may include a polymer-based material. The polymer-based material may include silicon-based resin, acryl-based resin (e.g., poly(methyl methacrylate), polyacrylic acid, etc.), epoxy-based resin, polyimide, and polyethylene.

The first inorganic encapsulation layer410formed by CVD has an approximately uniform thickness, and an upper surface of the first inorganic encapsulation layer410is not flat, as shown inFIG.5. However, an upper surface of the organic encapsulation layer420may have an approximately flat shape, and accordingly, the second inorganic encapsulation layer430on the organic encapsulation layer420may also have an approximately flat shape.

The bank layer500including the first to third bank openings501,502, and503may be disposed on the encapsulation layer400. The first to third bank openings501,502, and503of the bank layer500may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively. The first bank opening501of the bank layer500may correspond to the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may correspond to the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may correspond to the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313.

For example, when viewed from a direction (e.g., a z-axis direction) perpendicular to the first substrate100, the first bank opening501of the bank layer500may overlap the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may overlap the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may overlap the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313. Similarly, the first bank opening501of the bank layer500may correspond to the first pixel electrode311, the second bank opening502of the bank layer500may correspond to the second pixel electrode312, and the third bank opening503of the bank layer500may correspond to the third pixel electrode313.

In an embodiment, an area of the first bank opening501of the bank layer500may be greater than an area of the first pixel opening OP1of the pixel-defining layer PDL, an area of the second bank opening502may be greater than an area of the second pixel opening OP2, and an area of the third bank opening503may be greater than an area of the third pixel opening OP3. Accordingly, light generated on the first pixel opening OP1of the pixel-defining layer PDL may be sufficiently incident into the first bank opening501of the bank layer500, light generated on the second pixel opening OP2of the pixel-defining layer PDL may be sufficiently incident into the second bank opening502of the bank layer500, and light generated on the third pixel opening OP3of the pixel-defining layer PDL may be sufficiently incident into the third bank opening503of the bank layer500.

The bank layer500may include various materials, for example, an organic material, such as BCB or HMDSO. When necessary, the bank layer500may include a photoresist material, and through this, the bank layer500may be readily formed through a process, such as exposure and development. Because the bank layer500is formed on the first substrate100through a process, such as exposure and development, it may be shown such that the bank layer500has a reverse-tapered shape with reference to the first substrate100. For example, an area of a surface of the bank layer500in a direction toward the first substrate100may be less than an area of a surface of the bank layer500in a direction toward the second substrate900.

In an embodiment, as shown inFIG.5, the bank layer500may include a first bank layer510having a lyophilic surface and a second bank layer520having a lyophobic surface. For example, the first bank layer510including a lyophilic material may be located on the encapsulation layer400, and the second bank layer520including a lyophobic surface may be located on the first bank layer510. In another embodiment, the first bank layer510and the second bank layer520may include a same material as each other, and lyophobic properties may be rendered only to the surface of the second bank layer520by using CF4plasma treatment or the like.

The blue light Lb generated by the first light-emitting diode LED1may be converted into the red light Lr by the first quantum dot layer610located in the first bank opening501, and emitted to the outside. The first quantum dot layer610described above may overlap the first pixel electrode311when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The first quantum dot layer610may include a photosensitive polymer, quantum dots, and scattering particles, which have light-transmitting properties.

As described above, quantum dots of the first quantum dot layer610may include a material selected from among Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group III-VI semiconductor compounds, Group I-III-VI semiconductor compounds, Group IV-VI semiconductor compounds, or any mixture thereof. A diameter of such a quantum dot may be, for example, in a range of about 1 nm to about 10 nm.

The blue light Lb generated by the second light-emitting diode LED2may be converted into the green light Lg by the second quantum dot layer620located in the second bank opening502, and emitted to the outside. The second quantum dot layer620described above may overlap the second pixel electrode312when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The second quantum dot layer620may include a photosensitive polymer, quantum dots, and scattering particles, which have light-transmitting properties.

As described above, quantum dots of the second quantum dot layer620may include a material selected from among Group III-V compounds, Group III-VI compounds, Group II-VI compounds, Group I-III-VI compounds, and a mixture thereof. In an embodiment, the second quantum dot layer620may include InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof.

A first organic capping layer640may be located on the second quantum dot layer620in the second bank opening502. The first organic capping layer640described above may overlap the second pixel electrode312when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100.

The first organic capping layer640may be a photosensitive polymer. For example, a monomer for forming the first organic capping layer640may be photosensitive acryl-based resin. In an embodiment, the monomer for forming the first organic capping layer640may include hexamethylene diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, or any mixture thereof.

As shown inFIG.6, the second quantum dot layer620may have a concave shape in which a thickness t1of a central portion is less than a thickness t2of a peripheral portion adjacent to a sidewall of the second bank opening502. The first organic capping layer640may have a constant thickness ct on an upper surface620usof the second quantum dot layer620. For example, an upper surface640usof the first organic capping layer640may have a same or similar shape as or to the upper surface620usof the second quantum dot layer620.

In an embodiment, a fixed point PP at which the upper surface640usof the first organic capping layer640contacts a sidewall of the second bank opening502may coincide with or be adjacent to a point at which an interface between the first bank layer510and the second bank layer520contacts the sidewall of the second bank opening502. For example, the fixed point PP may coincide with or be located adjacent to a point at which a surface of the sidewall of the second bank opening502changes from lyophilic to lyophobic. Because a surface of the first bank layer510is lyophilic and has a same or similar surface energy as the upper surface620usof the second quantum dot layer620, the first organic capping layer640may be uniformly distributed to have the constant thickness ct on the upper surface620usof the second quantum dot layer620. In an embodiment, the thickness ct of the first organic capping layer640may be in a range of about 0.1 μm to about 3 μm.

The first organic capping layer640may prevent or reduce reduction in light conversion efficiency due to exposure of the second quantum dot layer620to light and/or oxygen before an inorganic capping layer PVL to be described later is formed. For example, when quantum dots including InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof are exposed to light and/or oxygen due to a structure of a shell, light conversion efficiency may rapidly decrease. Accordingly, in the display apparatus according to an embodiment, the first organic capping layer640prevents or reduces reduction of light conversion efficiency of the second quantum dot layer620so that a high-quality image may be displayed.

The blue light Lb generated in the third light-emitting diode LED3may be emitted to the outside without wavelength conversion. In an embodiment, the transmissive layer630may be located in the third bank opening503of the bank layer500overlapping the third pixel electrode313. The transmissive layer630may overlap the third pixel electrode313when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The transmissive layer630may include a photosensitive polymer having light transmittance and scattering particles.

The inorganic capping layer PVL may be located on the bank layer500to cover the first quantum dot layer610, the first organic capping layer640, and the transmissive layer630. The inorganic capping layer PVL may include an inorganic insulating material, such as silicon oxide, silicon nitride, and/or silicon oxynitride.

The color filter layer800may be located on a lower surface of the second substrate900in a direction (e.g., a −z direction) to the first substrate100. In the disclosure, when an element is located on the lower surface of the second substrate900in the direction (e.g., a −z direction) to the first substrate100, it may denote that the element is formed on the second substrate900and the second substrate900is flipped and bonded to be located between the first substrate100and the second substrate900. The color filter layer800may include the first to third filter openings801,802, and803. The first to third filter openings801,802, and803of the color filter layer800may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively.

The color filter layer800may include the first color filter layer810transmitting only light of a wavelength in a range of about 625 nm to about 780 nm, the second color filter layer820transmitting only light of a wavelength in a range of about 495 nm to about 570 nm, and the third color filter layer830transmitting only light of a wavelength in a range of about 450 nm to about 495 nm.

The first color filter layer810may include an opening corresponding to the second pixel electrode312and the third pixel electrode313. The second color filter layer820may include an opening corresponding to the first pixel electrode311and the third pixel electrode313. The third color filter layer830may include an opening corresponding to the first pixel electrode311and the second pixel electrode312. For example, a first filter opening801defined by overlapping the opening of the second color filter layer820and the opening of the third color filter layer830may be located on the first quantum dot layer610, and the first color filter layer810may fill the first filter opening801described above. A second filter opening802defined by overlapping the opening of the first color filter layer810and the opening of the third color filter layer830may be located on the second quantum dot layer620, and the second color filter layer820may fill the second filter opening802described above. A third filter opening803defined by the opening of the first color filter layer810and the opening of the second color filter layer820may be located on the transmissive layer630, and the third color filter layer830may fill the third filter opening803described above.

At least two layers from among the first color filter layer810, the second color filter layer820, and the third color filter layer830may overlap each other in an area between the first to third filter openings801,802, and803. An area in which the at least two layers from among the first color filter layer810, the second color filter layer820, and the third color filter layer830may serve as a black matrix. Accordingly, when viewed from the direction perpendicular to the first substrate100, a shape and size of the red sub-pixel Pr may be defined by the first filter opening801. Similarly, a shape and size of the green sub-pixel Pg may be defined by the second filter opening802, and a shape and size of the blue sub-pixel Pb may be defined by the third filter opening803.

The first color filter layer810to the third color filter layer830described above may increase color purity of light emitted to the outside so that the quality of a displayed image may be improved. The first color filter layer810to the third color filter layer830may reduce external reflection by reducing a ratio that external light incident to the display apparatus from the outside is reflected by the first pixel electrode311to the third pixel electrode313and emitted to the outside.

The low-refractive index layer700may be located between the color filter layer800, and the bank layer500and the color conversion-transmissive layer600. The low-refractive index layer700may include an inorganic protective layer720and an organic low-refractive index layer710. The inorganic protective layer720may include an inorganic material, such as silicon oxide, silicon nitride, and silicon oxynitride, and may be formed by CVD. The inorganic protective layer720may prevent impurities from permeating into a lower surface of the organic low-refractive index layer710in the direction (e.g., a −z direction) to the first substrate100. The organic low-refractive index layer710may have a refractive index of about 1.2. Scattered light passing through the color conversion-transmissive layer600may be totally reflected at an interface of the organic low-refractive index layer710and re-scattered within the color conversion-transmissive layer600. Accordingly, the low-refractive index layer700may change a lateral side scattering into a front side scattering so that luminance may be improved.

The first substrate100and the second substrate900may be bonded together outside a display area by a bonding member, such as a sealant. When desirable, a filler (not shown) may fill a space between a stacked body on the first substrate100and a stacked body on the second substrate900. For example, the filler may fill a space between the encapsulation layer400and the low-refractive index layer700. Such a filler may include a resin, such as acrylic or epoxy.

FIGS.7A and7Bare each a schematic cross-sectional view of a part of the display apparatus according to an embodiment.FIGS.7A and7Bcorrespond to enlarged cross-sections of region II inFIG.5.FIGS.7A and7Bdiffer fromFIG.6, at least in cross-sectional shapes of the second quantum dot layer620and the first organic capping layer640. Hereinafter, descriptions of elements that are same or similar as or to each other may be omitted, and only differences may be described.

Referring toFIG.7A, the second quantum dot layer620may have a concave shape in which a thickness t1of a central portion is less than a thickness t2of a peripheral portion adjacent to a sidewall of the second bank opening502. Depending on an amount of a material for forming the first organic capping layer640sprayed into the second bank opening502by using an inkjet printing method, the first organic capping layer640may have a convex shape in which a thickness ct1of a central portion is greater than a thickness ct2of a peripheral portion adjacent to a sidewall of the second bank opening502. Each of the thickness ct1of the central portion of the first organic capping layer640and the thickness ct2of the peripheral portion may be in a range of about 0.1 nm to about 3 nm.

Referring toFIG.7B, depending on an amount of a material for forming the second quantum dot layer620sprayed into the second bank opening502by using an inkjet printing method, the second quantum dot layer620may have a convex shape in which the thickness t1of the central portion is greater than the thickness t2of the peripheral portion adjacent to the sidewall of the second bank opening502. The first organic capping layer640may have the constant thickness ct on the upper surface620usof the second quantum dot layer620. For example, the upper surface640usof the first organic capping layer640may have a same or similar shape as or to the upper surface620usof the second quantum dot layer620.

Because a surface of the second bank layer520is lyophobic, as shown inFIGS.7A and7B, the fixed point PP at which the upper surface640usof the first organic capping layer640contacts the sidewall of the second bank opening502may coincide with or be adjacent to the point at which the interface between the first bank layer510and the second bank layer520contacts the sidewall of the second bank opening502.

FIG.8is a schematic cross-sectional view of a part of the display apparatus according to an embodiment.FIG.8may correspond to a cross-section of the display apparatus, taken along line I-I′ inFIG.1.FIG.8differs fromFIG.5, at least in that a second organic capping layer650is located on the first quantum dot layer610in the first bank opening501. Hereinafter, descriptions of elements that are same or similar as or to each other may be omitted, and only differences may be described.

The second organic capping layer650may be located on the first quantum dot layer610in the first bank opening501. The second organic capping layer650may overlap the first pixel electrode311when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100.

The second organic capping layer650may be a photosensitive polymer. For example, a monomer for forming the second organic capping layer650may be a photosensitive acryl-based resin. In an embodiment, the monomer for forming the second organic capping layer650may include hexamethylene diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, or any mixture thereof. In an embodiment, the first organic capping layer640and the second organic capping layer650may include a same material as each other.

As shown inFIG.8, the first quantum dot layer610may have a concave shape in which a thickness of a central portion is less than a thickness of a peripheral portion adjacent to a sidewall of the first bank opening501. The second organic capping layer650may have a constant thickness on an upper surface of the first quantum dot layer610. A fixed point at which the upper surface of the second organic capping layer650contacts the sidewall of the first bank opening501may coincide with or be adjacent to a point at which the interface between the first bank layer510and the second bank layer520contacts the sidewall of the first bank opening501. In an embodiment, the thickness of the second organic capping layer650may be in a range of about 0.1 μm to about 3 μm.

In another embodiment, the first quantum dot layer610and the second organic capping layer650may have a similar structure to a structure of the second quantum dot layer620and the first organic capping layer640shown inFIG.7A. For example, the first quantum dot layer610may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to a sidewall of the first bank opening501, and the second organic capping layer650may have a constant thickness on the upper surface of the first quantum dot layer610.

In another embodiment, the first quantum dot layer610and the second organic capping layer650may have a similar structure to a structure of the second quantum dot layer620and the first organic capping layer640shown inFIG.7B. The first quantum dot layer610may have a concave shape in which a thickness of a central portion is less than a thickness of a peripheral portion adjacent to the sidewall of the first bank opening501, and the second organic capping layer650may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to the sidewall of the first bank opening501.

The second organic capping layer650may prevent or reduce reduction in light conversion efficiency due to exposure of the first quantum dot layer610to light and/or oxygen before an inorganic capping layer PVL is formed. For example, although quantum dots including InP have relatively high stability, when a delay time prior to formation of the inorganic capping layer PVL exceeds a day, light conversion efficiency may decrease. Accordingly, in the display apparatus according to an embodiment, the first organic capping layer640is located on the second quantum dot layer620, and the second organic capping layer650is located on the first quantum dot layer610, and thus, even when a delay time increases during a process, a decrease in light conversion efficiency of the first and second quantum dot layers610and620may be prevented or reduced.

On the other hand, the transmissive layer630does not include quantum dots, and thus, an organic capping layer may not be located on the transmissive layer630.

FIGS.9A to9Fare schematic cross-sectional views sequentially illustrating some operations of a method of manufacturing the display apparatus, according to an embodiment.

Referring toFIG.9A, the first substrate100, and the circuit layer200, the light-emitting diode layer300, and the encapsulation layer400on the first substrate100may be prepared.

The circuit layer200may include first to third sub-pixel circuits PC1, PC2, and PC3, and the first to third sub-pixel circuits PC1, PC2, and PC3may be electrically connected to first to third light-emitting diodes LED1, LED2, and LED3of a light-emitting diode layer300, respectively. The circuit layer200may include the buffer layer201, the gate insulating layer203, the interlayer insulating layer205, and the planarization layer207on, under, and/or between each of the elements of the first to third sub-pixel circuits PC1, PC2, and PC3.

The first light-emitting diode LED1may include the first pixel electrode311, the opposite electrode330, and the intermediate layer320located between the first pixel electrode311and the opposite electrode330, and an emission layer. The second light-emitting diode LED2may include the second pixel electrode312, the opposite electrode330, and the intermediate layer320located between the second pixel electrode312and the opposite electrode330, and an emission layer. Similarly, the third light-emitting diode LED3may include the third pixel electrode313, the opposite electrode330, and the intermediate layer320located between the third pixel electrode313and the opposite electrode330and an emission layer.

The pixel-defining layer PDL may be disposed on the planarization layer207. The pixel-defining layer PDL may include pixel openings respectively corresponding to the first to third pixel electrodes311,312, and313.

The encapsulation layer400may cover the first to third light-emitting diodes LED1, LED2, and LED3. The encapsulation layer400may include the first inorganic encapsulation layer410, the second inorganic encapsulation layer430, and the organic encapsulation layer420therebetween. The upper surface of the organic encapsulation layer420may have an approximately flat shape, and accordingly, the second inorganic encapsulation layer430on the organic encapsulation layer420may also have an approximately flat shape.

Referring toFIG.9B, the bank layer500may be formed on the second inorganic encapsulation layer430. The bank layer500may include the first bank layer510and the second bank layer520located on the first bank layer510. A surface of the first bank layer510may be lyophilic, and a surface of the second bank layer520may be lyophobic.

The bank layer500may include the first to third bank openings501,502, and503. The first to third bank openings501,502, and503of the bank layer500may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively. The first bank opening501of the bank layer500may correspond to the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may correspond to the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may correspond to the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313.

Because the first to third bank openings501,502, and503are formed on the first substrate100by using a photolithography process, such as exposure and development, an area of a surface of the bank layer500in a direction toward the first substrate100may be less than an area of a surface in a direction toward the second substrate900. Accordingly, as shown inFIG.9B, the bank layer500may have a reverse-tapered shape with reference to the first substrate100.

Referring toFIG.9C, by using an inkjet printing process, a first ink Ink1may be sprayed into the first bank opening501, a second ink Ink2may be sprayed into the second bank opening502, and a third ink Ink3may be sprayed into the third bank opening503.

The first ink Ink1may include a material611forming the first quantum dot layer610. In an embodiment, the first ink Ink1may include a photosensitive monomer, quantum dots, and scattering particles. Here, quantum dots included in the first ink Ink1may include a material selected from among Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group III-VI semiconductor compounds, Group I-III-VI semiconductor compounds, Group IV-VI semiconductor compounds, or any mixture thereof.

The second ink Ink2may include a material621forming the second quantum dot layer620. In an embodiment, the second ink Ink2may include a photosensitive monomer, quantum dots, and scattering particles. Here, the quantum dots included in the second ink Ink2may include InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof.

The third ink Ink3may include a material631forming the transmissive layer630. In an embodiment, the third ink Ink3may include a photosensitive monomer, quantum dots, and scattering particles.

The material611forming the first quantum dot layer610may be located in the first bank opening501. The fixed point PP at which an upper surface of the material611forming the first quantum dot layer610contacts the sidewall of the first bank opening501may coincide with or be adjacent to a point at which the interface between the first bank layer510and the second bank layer520contacts the sidewall of the first bank opening501. A shape of the upper surface of the material611forming the first quantum dot layer610may be determined by adjusting a sprayed amount of the first ink Ink1. For example, when the sprayed amount of the first ink Ink1is small, the upper surface of the material611forming the first quantum dot layer610may have a concave shape. When the sprayed amount of the first ink Ink1is large, the upper surface of the material611forming the first quantum dot layer610may have a convex shape.

The material621forming the second quantum dot layer620may be located in the second bank opening502. Similarly, a shape of an upper surface of the material621forming the second quantum dot layer620may be determined by adjusting a sprayed amount of the second ink Ink2.

The material631forming the transmissive layer630may be located in the third bank opening503. A shape of an upper surface of the material631forming the transmissive layer630may be determined by adjusting a sprayed amount of the third ink Ink3.

Referring toFIG.9D, a fourth ink Ink4may be sprayed into the second bank opening502by using an inkjet printing process.

The fourth ink Ink4may include a material641forming the first organic capping layer640. The material641forming the first organic capping layer640may be a photosensitive acryl-based monomer. In an embodiment, the material641forming the first organic capping layer640may include hexamethylene diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, or any mixture thereof.

In an embodiment, the photosensitive monomer included in the material621forming the second quantum dot layer620may be a same material as the material641forming the first organic capping layer640.

In an embodiment, a viscosity of the fourth ink Ink4may be in a range of about 1 cps to about 30 cps.

A thickness of the material641forming the first organic capping layer640may be in a range of about 0.1 nm to about 3 nm. When the thickness of the material641forming the first organic capping layer640is less than 0.1 nm, the material641forming the first organic capping layer640may not be sufficiently applied onto the material621forming the second quantum dot layer620. When a thickness of the material641forming the first organic capping layer640is greater than 3 nm, curing efficiency may decrease.

In an embodiment, the material641forming the first organic capping layer640may have a constant thickness, as shown inFIG.13D. For example, an upper surface641usof the material641forming the first organic capping layer640may have a similar shape to a shape of an upper surface621usof the material621forming the second quantum dot layer620.

In another embodiment, the material641forming the first organic capping layer640may have a convex shape in which a thickness of a central portion is greater than a thickness of a peripheral portion adjacent to a sidewall of the second bank opening502.

Although not shown inFIG.9D, a material forming a second organic capping layer may be applied onto the material611forming the first quantum dot layer610by spraying the fourth ink Ink4into the first bank opening501.

Although not shown inFIG.9E, an infrared ray may be irradiated to the material611forming the first quantum dot layer610, the material621forming the second quantum dot layer620, the material631forming the transmissive layer630, and the material641forming the first organic capping layer640, so that the first quantum dot layer610, the second quantum dot layer620, the transmissive layer630, and the first organic capping layer640may be formed.

Photosensitive monomers included in the material611forming the first quantum dot layer610, the material621forming the second quantum dot layer620, the material631forming the transmissive layer630, and the material641forming the first organic capping layer640may polymerize with each other and form a polymer. Accordingly, the material611forming the first quantum dot layer610, the material621forming the second quantum dot layer620, the material631forming the transmissive layer630, and the material641forming the first organic capping layer640may lose the flexibility thereof and be cured.

The second quantum dot layer620and the first organic capping layer640may be crosslinked to each other and formed. Until the inorganic capping layer PVL is formed, a decrease in light conversion efficiency by exposure of the second quantum dot layer620to light and/or oxygen may be prevented or reduced by the first organic capping layer640.

Thereafter, by using CVD, the inorganic capping layer PVL may be formed on the bank layer500to cover the first quantum dot layer610, the first organic capping layer640, and the transmissive layer630.

Referring toFIG.9F, the second substrate900, in which the color filter layer800and the low-refractive index layer700are located on a lower surface thereof in a direction (e.g., a −z direction) to the first substrate100, may be bonded to the first substrate100.

The color filter layer800may be located on the lower surface of the second substrate900in the direction (e.g., a −z direction) to the first substrate100. The color filter layer800may include the first to third filter openings801,802, and803. The first to third filter openings801,802, and803of the color filter layer800may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively.

The color filter layer800may include the first color filter layer810transmitting only light of a wavelength in a range of about 625 nm to about 780 nm, the second color filter layer820transmitting only light of a wavelength in a range of about 495 nm to about 570 nm, and the third color filter layer830transmitting only light of a wavelength in a range of about 450 nm to about 495 nm. The third color filter layer830may be formed on a lower surface of the second substrate900in the direction (e.g., a −z direction) to the first substrate100, the first color filter layer810may be formed on a lower surface of the third color filter layer830, and the second color filter layer820may be formed on a lower surface of the first color filter layer810.

At least two layers from among the first color filter layer810, the second color filter layer820, and the third color filter layer830may be formed to overlap each other in an area between the first to third filter openings801,802, and803.

The low-refractive index layer700may include the organic low-refractive index layer710and the inorganic protective layer720. The organic low-refractive index layer710may include an organic material having a refractive index of about 1.2, and may directly contact the color filter layer800. The inorganic protective layer720may include an inorganic material, such as silicon oxide, silicon nitride, and silicon oxynitride, and may be formed by CVD.

The first substrate100and the second substrate900may be bonded together outside a display area by a bonding member, such as a sealant. When desirable, a filler (not shown) may fill a space between a stacked body on the first substrate100and a stacked body on the second substrate900.

FIG.10is a schematic cross-sectional view of a part of the display apparatus according to an embodiment, andFIG.11is an enlarged schematic cross-sectional view of region III of the display apparatus shown inFIG.10.FIG.10differs from FIG.5, at least in that the bank layer500and the color conversion-transmissive layer600are formed on a lower surface of the low-refractive index layer700in the direction (e.g., a −z direction) to the first substrate100. Hereinafter, descriptions of elements that are same or similar as or to each other may be omitted, and only differences may be described.

Referring toFIG.10, the color filter layer800may be located on the lower surface of the second substrate900in the direction (e.g., a −z direction) to the first substrate100. The color filter layer800may include the first to third filter openings801,802, and803. The first to third filter openings801,802, and803of the color filter layer800may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively.

The low-refractive index layer700may be located on the lower surface of the color filter layer800in the direction (e.g., a −z direction) to the first substrate100. The low-refractive index layer700may include the inorganic protective layer720and the organic low-refractive index layer710. The organic low-refractive index layer710may have a refractive index of about 1.2. The organic low-refractive index layer710may directly contact the color filter layer800, and a lower surface of the organic low-refractive index layer710in the direction (e.g., a −z direction) to the first substrate100may have an approximately flat shape.

The inorganic protective layer720may include an inorganic material, such as silicon oxide, silicon nitride, and silicon oxynitride, and may be formed by CVD. The inorganic protective layer720may prevent impurities from permeating into the lower surface of the organic low-refractive index layer710in the direction (e.g., a −z direction) to the first substrate100.

The bank layer500may be disposed on a lower surface of the inorganic protective layer720in the direction (e.g., a −z direction) to the first substrate100. The first to third bank openings501,502, and503of the bank layer500may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively. The first bank opening501of the bank layer500may correspond to the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may correspond to the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may correspond to the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313.

For example, when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100, the first bank opening501of the bank layer500may overlap the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may overlap the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may overlap the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313. Similarly, the first bank opening501of the bank layer500may correspond to the first pixel electrode311, the second bank opening502of the bank layer500may correspond to the second pixel electrode312, and the third bank opening503of the bank layer500may correspond to the third pixel electrode313.

Because the bank layer500is formed on the second substrate900through a process, such as exposure and development, it may be shown such that the bank layer500has a reverse-tapered shape with reference to the second substrate900. For example, the area of the surface of the bank layer500in the direction toward the first substrate100may be greater than the area of the surface of the bank layer500in the direction toward the second substrate900.

The bank layer500may include the first bank layer510having a lyophilic surface and the second bank layer520having a lyophobic surface. For example, the first bank layer510having the lyophilic surface may be located on the lower surface of the inorganic protective layer720in the direction (e.g., a −z direction) to the first substrate100, and the second bank layer520having the lyophobic surface may be located on the lower surface of the first bank layer510in the direction (e.g., a −z direction) to the first substrate100.

The blue light Lb generated by the first light-emitting diode LED1may be converted into the red light Lr by the first quantum dot layer610located in the first bank opening501, and emitted to the outside. The first quantum dot layer610described above may overlap the first pixel electrode311when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The first quantum dot layer610may include a photosensitive polymer, quantum dots, and scattering particles, which have light-transmitting properties.

The quantum dots of the first quantum dot layer610may include a material selected from among Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group III-VI semiconductor compounds, Group I-III-VI semiconductor compounds, Group IV-VI semiconductor compounds, or any mixture thereof.

The blue light Lb generated by the second light-emitting diode LED2may be converted into the green light Lg by the second quantum dot layer620located in the second bank opening502, and emitted to the outside. The second quantum dot layer620described above may overlap the second pixel electrode312when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The second quantum dot layer620may include a photosensitive polymer, quantum dots, and scattering particles, which have light-transmitting properties.

As described above, the quantum dots of the second quantum dot layer620may include a material selected from among Group III-V compounds, Group III-VI compounds, Group II-VI compounds, Group I-III-VI compounds, and a mixture thereof. In an embodiment, the second quantum dot layer620may include InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof.

The first organic capping layer640may be located on a lower surface of the second quantum dot layer620in the direction (e.g., a −z direction) to the first substrate100within the second bank opening502. The first organic capping layer640described above may overlap the second pixel electrode312when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100.

The first organic capping layer640may be a photosensitive polymer. For example, a monomer for forming the first organic capping layer640may be photosensitive acryl-based resin. In an embodiment, the monomer for forming the first organic capping layer640may include hexamethylene diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, or any mixture thereof.

As shown inFIG.11, with respect to the second substrate900, the second quantum dot layer620may have a concave shape in which the thickness t1of a central portion is less than the thickness t2of a peripheral portion adjacent to the sidewall of the second bank opening502. The first organic capping layer640may have the constant thickness ct on the upper surface620usof the second quantum dot layer620in the direction (e.g., a −z direction) to the first substrate100. For example, the upper surface640usof the first organic capping layer640in the direction (e.g., a −z direction) to the first substrate100may have a same or similar shape as or to a shape of the upper surface620usof the second quantum dot layer620in the direction (e.g., a −z direction) to the first substrate100. In an embodiment, the thickness ct of the first organic capping layer640may be in a range of about 0.1 μm to about 3 μm.

Although not shown inFIG.10, a second organic capping layer (not shown) may be located on the first quantum dot layer610. The second organic capping layer may be a photosensitive polymer. In an embodiment, the first organic capping layer640and the second organic capping layer may include a same material as each other. In an embodiment, the thickness of the second organic capping layer may be in a range of about 0.1 μm to about 3 μm.

The inorganic capping layer PVL may be located on the bank layer500to cover the first quantum dot layer610, the first organic capping layer640, and the transmissive layer630. The inorganic capping layer PVL may include an inorganic insulating material, such as silicon oxide, silicon nitride, and/or silicon oxynitride.

The first substrate100and the second substrate900may be bonded together outside a display area by a bonding member, such as a sealant. When desirable, a filler (not shown) may fill a space between a stacked body on the first substrate100and a stacked body on the second substrate900. For example, the filler may fill a space between the encapsulation layer400and the inorganic capping layer PVL.

FIGS.12A and12Bare each a schematic cross-sectional view of a part of the display apparatus according to an embodiment.FIGS.12A and12Bdiffer fromFIG.11, at least in the cross-sectional shapes of the second quantum dot layer620and the first organic capping layer640. Hereinafter, descriptions of elements that are same or similar as or to each other may be omitted, and only differences may be described.

Referring toFIG.12A, with respect to the second substrate900, the second quantum dot layer620may have a concave shape in which the thickness t1of a central portion is less than the thickness t2of a peripheral portion adjacent to the sidewall of the second bank opening502. Depending on an amount of a material for forming the first organic capping layer640sprayed into the second bank opening502by using an inkjet printing method, the first organic capping layer640may have a convex shape in which a thickness ct1of a central portion is greater than a thickness ct2of a peripheral portion adjacent to a sidewall of the second bank opening502. Each of the thickness ct1of the central portion of the first organic capping layer640and the thickness ct2of the peripheral portion may be in a range of about 0.1 nm to about 3 nm.

Referring toFIG.12B, with respect to the second substrate900, the second quantum dot layer620may have a convex shape in which the thickness t1of a central portion is greater than the thickness t2of a peripheral portion adjacent to the sidewall of the second bank opening502. The first organic capping layer640may have the constant thickness ct on the upper surface620usof the second quantum dot layer620in the direction (e.g., a −z direction) to the first substrate100. For example, the upper surface640usof the first organic capping layer640in the direction (e.g., a −z direction) to the first substrate100may have a same or similar shape as or to a shape of the upper surface620usof the second quantum dot layer620in the direction (e.g., a −z direction) to the first substrate100.

Because a surface of the second bank layer520is lyophobic, as shown inFIGS.12A and12B, the fixed point PP at which the upper surface640usof the first organic capping layer640contacts the sidewall of the second bank opening502may coincide with or be adjacent to the point at which the interface between the first bank layer510and the second bank layer520contacts the sidewall of the second bank opening502.

FIGS.13A to13Fare schematic cross-sectional views sequentially illustrating some operations of a method of manufacturing the display apparatus, according to an embodiment.

Referring toFIG.13A, the second substrate900, the color filter layer800on the second substrate900, and the low-refractive index layer700may be prepared.

The color filter layer800may include the first to third filter openings801,802, and803. When the second substrate900and the first substrate100are bonded together, the first to third filter openings801,802, and803of the color filter layer800may correspond to the first to third light-emitting diodes LED1, LED2, and LED3located on the first substrate100, respectively.

The color filter layer800may include the first color filter layer810transmitting only light of a wavelength in a range of about 625 nm to about 780 nm, the second color filter layer820transmitting only light of a wavelength in a range of about 495 nm to about 570 nm, and the third color filter layer830transmitting only light of a wavelength in a range of about 450 nm to about 495 nm.

The third color filter layer830including openings respectively corresponding to the first pixel electrode311and the second pixel electrode312may be formed on the second substrate900. The first color filter layer810including openings respectively corresponding to the second pixel electrode312and the third pixel electrode313may be formed on the third color filter layer830. The second color filter layer820including openings respectively corresponding to the first pixel electrode311and the third pixel electrode313may be formed on the first color filter layer810. The first filter opening801defined by overlapping the opening of the second color filter layer820and the opening of the third color filter layer830may be located on the first quantum dot layer610, and the first color filter layer810may fill the first filter opening801described above. The second filter opening802defined by overlapping the opening of the first color filter layer810and the opening of the third color filter layer830may be located on the second quantum dot layer620, and the second color filter layer820may fill the second filter opening802described above. The third filter opening803defined by the opening of the first color filter layer810and the opening of the second color filter layer820may be located on the transmissive layer630, and the third color filter layer830may fill the third filter opening803described above.

The organic low-refractive index layer710may be formed on the color filter layer800. The organic low-refractive index layer710may include an organic material having a refractive index of about 1.2. The organic low-refractive index layer710may include a relatively flat upper surface. The inorganic protective layer720may be formed on the organic low-refractive index layer710. The inorganic protective layer720may include an inorganic material, such as silicon oxide, silicon nitride, and silicon oxynitride, and may be formed by CVD.

Referring toFIG.13B, the bank layer500may be formed on the inorganic protective layer720. The bank layer500may include the first bank layer510and the second bank layer520located on the first bank layer510. A surface of the first bank layer510may be lyophilic, and a surface of the second bank layer520may be lyophobic.

The bank layer500may include the first to third bank openings501,502, and503. When the second substrate900and the first substrate100are bonded together, the first to third bank openings501,502, and503of the bank layer500may correspond to the first to third light-emitting diodes LED1, LED2, and LED3located on the first substrate100, respectively. The first bank opening501of the bank layer500may correspond to the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may correspond to the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may correspond to the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313.

Because the first to third bank openings501,502, and503are formed on the second substrate900by using a photolithography process, such as exposure and development, the area of the surface of the bank layer500in the direction toward the first substrate100may be greater than an area of the surface in the direction toward the second substrate900. Accordingly, as shown inFIG.9B, the bank layer500may have a reverse-tapered shape with reference to the second substrate900.

Referring toFIG.13C, by using an inkjet printing process, the first ink Ink1may be sprayed into the first bank opening501, the second ink Ink2may be sprayed into the second bank opening502, and the third ink Ink3may be sprayed into the third bank opening503.

The first ink Ink1may include the material611forming the first quantum dot layer610. In an embodiment, the first ink Ink1may include a photosensitive monomer, quantum dots, and scattering particles. Here, the quantum dots included in the first ink Ink1may include a material selected from among Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group III-VI semiconductor compounds, Group I-III-VI semiconductor compounds, Group IV-VI semiconductor compounds, or any mixture thereof.

The second ink Ink2may include the material621forming the second quantum dot layer620. In an embodiment, the second ink Ink2may include a photosensitive monomer, quantum dots, and scattering particles. Here, the quantum dots included in the second ink Ink2may include InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof.

The third ink Ink3may include the material631forming the transmissive layer630. In an embodiment, the third ink Ink3may include a photosensitive monomer, quantum dots, and scattering particles.

By adjusting a sprayed amount of each of the first ink Ink1, the second ink Ink2, and the third ink Ink3, shapes of upper surfaces of the material611forming the first quantum dot layer610, the material621forming the second quantum dot layer620, and the material631forming the transmissive layer630may be determined. For example, as shown inFIG.13C, the material621forming the second quantum dot layer620may have a concave shape in which a thickness of a central portion is less than a thickness of a peripheral portion. In another embodiment, the material621forming the second quantum dot layer620may have a convex shape in which the thickness of the central portion is greater than the thickness of the peripheral portion.

Referring toFIG.13D, a fourth ink Ink4may be sprayed into the second bank opening502by using an inkjet printing process.

The fourth ink Ink4may include the material641forming the first organic capping layer640. In an embodiment, the photosensitive monomer included in the material621forming the second quantum dot layer620may be the same material as the material641forming the first organic capping layer640.

The thickness of the material641forming the first organic capping layer640may be in a range of about 0.1 nm to about 3 nm. In an embodiment, the material641forming the first organic capping layer640may have a constant thickness, as shown inFIG.13D. For example, the upper surface641usof the material641forming the first organic capping layer640may have a similar shape to the shape of the upper surface621usof the material621forming the second quantum dot layer620.

In another embodiment, the material641forming the first organic capping layer640may have a convex shape in which the thickness of the central portion is greater than a thickness of the peripheral portion adjacent to the sidewall of the second bank opening502.

Although not shown inFIG.13D, the material forming the second organic capping layer may be applied onto the material611forming the first quantum dot layer610by spraying the fourth ink Ink4into the first bank opening501.

Although not shown inFIG.13E, an infrared ray may be irradiated to the material611forming the first quantum dot layer610, the material621forming the second quantum dot layer620, the material631forming the transmissive layer630, and the material641forming the first organic capping layer640, so that the first quantum dot layer610, the second quantum dot layer620, the transmissive layer630, and the first organic capping layer640may be formed.

The second quantum dot layer620and the first organic capping layer640may be crosslinked to each other and formed. Until the inorganic capping layer PVL is formed, a decrease in light conversion efficiency by exposure of the second quantum dot layer620to light and/or oxygen may be prevented or reduced by the first organic capping layer640.

Thereafter, by using CVD, the inorganic capping layer PVL may be formed on the bank layer500to cover the first quantum dot layer610, the first organic capping layer640, and the transmissive layer630.

Referring toFIG.13F, the first substrate100including the circuit layer200, the light-emitting diode layer300, and the encapsulation layer400may be bonded to the second substrate900.

The first substrate100and the second substrate900may be bonded together such that the color filter layer800faces the direction (e.g., a −z direction) to the first substrate100. In an embodiment, the first to third filter openings801,802, and803of the color filter layer800may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively.

The first substrate100and the second substrate900may be bonded together outside a display area by a bonding member, such as a sealant. When desirable, a filler (not shown) may fill a space between a stacked body on the first substrate100and a stacked body on the second substrate900.

FIG.14is a graph showing a light absorption efficiency increase rate and a light conversion efficiency increase rate according to a thickness of a quantum dot layer of a display apparatus according to an embodiment.

The light absorption efficiency increase rate and the light conversion efficiency increase rate may be calculated by comparing light absorption efficiency and light conversion efficiency of a quantum dot layer including AgInxGa(1-x)S2as a quantum dot, with light absorption efficiency and light conversion efficiency of a quantum dot layer that includes the same components as the quantum dot layer described above, but includes InP as a quantum dot.

As can be identified inFIG.14, when compared with the quantum dot layer including InP as a quantum dot, the light absorption efficiency of the quantum dot layer including AgInxGa(1-x)S2as a quantum dot may increase by 110% to 113%, and the light conversion efficiency may increase by 120% to 150%.

When InP is used as a quantum dot, a size of a quantum dot for converting blue light into green light may be about 2 nm. When the size of the quantum dot is less than or equal to about 2 nm, a non-absorption section may occur within a wavelength range of the blue light emitted by a light-emitting diode due to the quantum confinement effect.

On the other hand, Ag InxGa(1-x)S2has a smaller band gap than In P, and thus, the quantum dot size in which the quantum confinement effect occurs may be relatively large. Accordingly, by reducing the non-absorption section within the wavelength range of the blue light emitted by the light-emitting diode, high light absorption efficiency and light conversion efficiency may be obtained.

FIG.15is a graph showing light conversion efficiency according to a light exposure time of the display apparatus according to an experimental example and a comparative example, andFIG.16is a graph showing light conversion efficiency according to a light exposure time of the display apparatus according to an experimental example and comparative examples.

As shown inFIG.5, the circuit layer200, the light-emitting diode layer300, the encapsulation layer400, and the bank layer500are formed on the first substrate100. By an inkjet process, the first quantum dot layer610may be formed in the first bank opening501of the bank layer500, the second quantum dot layer620and the first organic capping layer640may be formed in the second bank opening502, and the transmissive layer630may be formed in the third bank opening503. The second quantum dot layer620may include AgInxGa(1-x)S2quantum dots. The inorganic capping layer PVL may be formed on the bank layer500to cover the first quantum dot layer610, the first organic capping layer640, and the transmissive layer630. Thereafter, the second substrate900is bonded onto the first substrate100to manufacture the display apparatus according to Experimental Example 1.

Although the display apparatus according to Comparative Example 1 is manufactured in the same manner as in the display apparatus according to Experimental Example 1, in the display apparatus according to the Comparative Example 1, an inorganic capping layer is formed on a second quantum dot layer instead of a first organic capping layer.

Although the display apparatus according to Comparative Example 2 is manufactured in the same manner as in the display apparatus according to Comparative Example 1, in the display apparatus according to Comparative Example 2, the second quantum dot layer includes InP quantum dots.

FIG.15shows light conversion efficiency of the second quantum dot layer when the display apparatuses according to Experimental Example 1 and Comparative Example 1 are exposed to light having a wavelength of about 460 nm under atmospheric conditions before forming the inorganic capping layer PVL.

In Comparative Example 1, it can be seen that the light conversion efficiency continuously decreases as the exposure time increases. This is because AgInxGa(1-x)S2quantum dots included in the second quantum dot layer are damaged by contact with oxygen or the like under atmospheric conditions. On the other hand, in Experimental Example 1, it can be identified that the light conversion efficiency of 100% or more is maintained even when the exposure time is increased.

FIG.16shows light conversion efficiency of the second quantum dot layer when the display apparatuses according to Experimental Example 1, Comparative Example 1, and Comparative Example 2 are exposed to light having a wavelength of 590 nm under atmospheric conditions before forming the inorganic capping layer PVL.

In Comparative Example 1, it can be identified that the light conversion efficiency continuously decreases as the exposure time increases. As described above, AgInxGa(1-x)S2quantum dots included in the second quantum dot layer are damaged by contact with oxygen or the like under atmospheric conditions.

In Comparative Example 2, when relatively stable InP quantum dots are included, the light conversion efficiency does not decrease until 1 day passes, but it can be identified that the light conversion efficiency decreases after 1 day has passed.

On the other hand, in Experimental Example 1, it can be identified that the light conversion efficiency of 100% or more is maintained even when the exposure time is 2 days. In Experimental Example 1, the first organic capping layer640blocks the second quantum dot layer620from contacting oxygen or the like, so that a decrease in the light conversion efficiency of the second quantum dot layer620during the delay time before the formation of the inorganic capping layer PVL may be prevented or reduced.

FIG.17is a schematic cross-sectional view of a part of the display apparatus according to an embodiment.FIG.17differs fromFIG.5, at least in that the low-refractive index layer700is formed on the bank layer500and the color conversion-transmissive layer600, and the color filter layer800is formed on the low-refractive index layer700, such that the second substrate is omitted. Hereinafter, descriptions of elements that are same or similar as or to each other may be omitted, and only differences may be described.

Referring toFIG.17, the bank layer500including the first to third bank openings501,502, and503may be disposed on the encapsulation layer400. The first to third bank openings501,502, and503of the bank layer500may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively. The first bank opening501of the bank layer500may correspond to the first pixel opening OP1of the pixel-defining layer PDL exposing the first pixel electrode311, the second bank opening502may correspond to the second pixel opening OP2of the pixel-defining layer PDL exposing the second pixel electrode312, and the third bank opening503may correspond to the third pixel opening OP3of the pixel-defining layer PDL exposing the third pixel electrode313.

In an embodiment, as shown inFIG.5, the bank layer500may include a first bank layer510having a lyophilic surface and a second bank layer520having a lyophobic surface. For example, the first bank layer510including a lyophilic material may be located on the encapsulation layer400, and the second bank layer520including a lyophobic surface may be located on the first bank layer510. In another embodiment, the first bank layer510and the second bank layer520may include a same material as each other, and lyophobic properties may be rendered only to the surface of the second bank layer520by using CF4plasma treatment or the like.

The blue light Lb generated by the first light-emitting diode LED1may be converted into the red light Lr by the first quantum dot layer610located in the first bank opening501, and emitted to the outside. The first quantum dot layer610described above may overlap the first pixel electrode311when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The first quantum dot layer610may include a photosensitive polymer, quantum dots, and scattering particles, which have light-transmitting properties.

The blue light Lb generated by the second light-emitting diode LED2may be converted into the green light Lg by the second quantum dot layer620located in the second bank opening502, and emitted to the outside. The second quantum dot layer620described above may overlap the second pixel electrode312when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The second quantum dot layer620may include a photosensitive polymer, quantum dots, and scattering particles, which have light-transmitting properties.

The quantum dots of the second quantum dot layer620may include a material selected from among Group III-V compounds, Group III-VI compounds, Group II-VI compounds, Group I-III-VI compounds, and a mixture thereof. In an embodiment, the second quantum dot layer620may include InxGa(1-x)P, AgInxGa(1-x)S2, AgInS2, AgGaS2, CuInS2, CuInSe2, CuGaS2, CuGaSe2, ZnSe, ZnTexSe(1-x), or any mixture thereof.

The first organic capping layer640may be located on the second quantum dot layer620in the second bank opening502. The first organic capping layer640described above may overlap the second pixel electrode312when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100.

The first organic capping layer640may be a photosensitive polymer. For example, a monomer for forming the first organic capping layer640may be photosensitive acryl-based resin. In an embodiment, the monomer for forming the first organic capping layer640may include hexamethylene diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, or any mixture thereof.

As shown inFIG.17, the first organic capping layer640may have a constant thickness on the upper surface of the second quantum dot layer620. For example, the upper surface of the first organic capping layer640may have a same or similar shape as or to the upper surface of the second quantum dot layer620. In another embodiment, the second quantum dot layer620may have a concave shape, and the first organic capping layer640may have a convex shape in which the thickness of the central portion is greater than the thickness of the peripheral portion adjacent to the second bank opening502.

A fixed point at which the upper surface of the first organic capping layer640contacts the sidewall of the second bank opening502may coincide with or be adjacent to a point at which the interface between the first bank layer510and the second bank layer520contacts the sidewall of the second bank opening502. For example, the fixed point may coincide with or be located adjacent to a point at which a surface of the sidewall of the second bank opening502changes from lyophilic to lyophobic.

The first organic capping layer640may prevent or reduce reduction in light conversion efficiency due to exposure of the second quantum dot layer620to light and/or oxygen before an inorganic capping layer PVL is formed.

The blue light Lb generated in the third light-emitting diode LED3may be emitted to the outside without wavelength conversion. In an embodiment, the transmissive layer630may be located in the third bank opening503of the bank layer500overlapping the third pixel electrode313. The transmissive layer630may overlap the third pixel electrode313when viewed from the direction (e.g., a z-axis direction) perpendicular to the first substrate100. The transmissive layer630may include a photosensitive polymer having light transmittance and scattering particles.

The inorganic capping layer PVL may be located on the bank layer500to cover the first quantum dot layer610, the first organic capping layer640, and the transmissive layer630. The inorganic capping layer PVL may include an inorganic insulating material, such as silicon oxide, silicon nitride, and/or silicon oxynitride.

The low-refractive index layer700may be located on the inorganic capping layer PVL. The low-refractive index layer700may include the organic low-refractive index layer710and the inorganic protective layer720. The organic low-refractive index layer710may have a refractive index of about 1.2. The organic low-refractive index layer710may be applied onto the bank layer500and the color conversion-transmissive layer600so as to provide a flat base surface to elements located over the organic low-refractive index layer710. Scattered light passing through the color conversion-transmissive layer600may be totally reflected at an interface of the organic low-refractive index layer710and re-scattered within the color conversion-transmissive layer600. The inorganic protective layer720may be formed on the organic low-refractive index layer710. The inorganic protective layer720may include an inorganic material, such as silicon oxide, silicon nitride, and silicon oxynitride, and may be formed by CVD.

The color filter layer800may be located on the inorganic protective layer720. After the inorganic protective layer720is formed, the color filter layer800may be formed through a continuous process on a base surface on which the inorganic protective layer720is provided.

The color filter layer800may include the first to third filter openings801,802, and803. The first to third filter openings801,802, and803of the color filter layer800may correspond to the first to third light-emitting diodes LED1, LED2, and LED3, respectively.

The color filter layer800may include the first color filter layer810transmitting only light of a wavelength in a range of about 625 nm to about 780 nm, the second color filter layer820transmitting only light of a wavelength in a range of about 495 nm to about 570 nm, and the third color filter layer830transmitting only light of a wavelength in a range of about 450 nm to about 495 nm.

The third color filter layer830may be located on the inorganic protective layer720, the first color filter layer810may be located on the third color filter layer830, and the second color filter layer820may be located on the first color filter layer810. At least two layers from among the first color filter layer810, the second color filter layer820, and the third color filter layer830may overlap each other in an area between the first to third filter openings801,802, and803. An area in which the at least two layers from among the first color filter layer810, the second color filter layer820, and the third color filter layer830may serve as a black matrix.

Because the color filter layer800is formed (e.g., directly formed) on a base surface provided by the inorganic protective layer720, the first color filter layer810, the second color filter layer820, and the third color filter layer830may contact (e.g., directly contact) the inorganic protective layer720.

A film layer FL may be located on the color filter layer800. The film layer FL may be bonded onto the color filter layer800through an adhesive layer, such as an optically clear adhesive or optically clear resin (OCR).

In some embodiments, the film layer FL may be provided as an anti-reflection film. The film layer FL may be provided as a polarization film. The polarization film may include a linear planarization plate and a phase delay film, such as a quarter-wave (λ/4) plate.

In the display apparatus1described with reference toFIG.17, because the color filter layer800is formed (e.g., directly formed) on the inorganic protective layer720, a second substrate for forming the color filter layer800may be omitted. Accordingly, a process of bonding the first substrate100and the second substrate together may be omitted, and thus, a manufacturing process may be simplified and a thickness of the display apparatus1may be reduced.

According to an embodiment configured as described above, a display apparatus on which a high-quality image may be displayed may be implemented. However, the scope of the disclosure is not limited by this effect.