Display device

Abstract

The display device (2) has a sub-pixel (SPr, SPg, SPb), an electron transport layer (ETg) overlaps the entirety of a pixel electrode (PEg) of the sub-pixel (SPg) in plan view, an electron transport layer (ETr) overlaps the entirety of a pixel electrode (PEr) of the sub-pixel (SPr) in plan view, and has an opening (Org) overlapping the inside of a peripheral end portion (EDg) of the pixel electrode (PEg) of the sub-pixel (SPg) in plan view.

Description

TECHNICAL FIELD

[0001] The present application relates to a display device. BACKGROUND

[0002] A display device is known in which functional layers such as a hole-transport layer and an electron-transport layer are formed to be common in all sub-pixels (Patent Literature 1). On the other hand, depending on the kind of sub-pixel, sometimes in order to improve the efficiency of recombination of holes injected from an anode and electrons injected from a cathode in a light-emitting layer, it is intended to form different functional layers for each sub-pixel.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: International Publication No. 2011 / 148791 (Published on December 1, 2011) SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the case where different functional layers are formed for each sub-pixel, there is a possibility that a defect or peeling occurs in the edge portion of the functional layer, which becomes a problem.

[0008] SOLUTION TO THE PROBLEM

[0009] An aspect of the present application relates to a display device including: pixel electrodes formed for each sub-pixel; a common electrode; a light-emitting layer formed between the pixel electrodes and the common electrode; and first and second functional layers formed between the light-emitting layer and the pixel electrodes or between the light-emitting layer and the common electrode, which are continuously formed across a plurality of the sub-pixels, the sub-pixels having a first sub-pixel that emits light of a first color and a second sub-pixel that emits light of a second color having a longer wavelength than the first color, the second functional layer overlapping the pixel electrode of the second sub-pixel as a whole in plan view, the first functional layer overlapping the pixel electrode of the first sub-pixel as a whole in plan view, and having an opening overlapping an inner side of a peripheral edge portion of the pixel electrode of the second sub-pixel in plan view.

[0010] EFFECT OF THE INVENTION

[0011] According to an aspect of the present application, it is possible to prevent a defect or peeling from occurring in the edge portion of the functional layer. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a flowchart showing an example of a manufacturing method of a display device.

[0013] Figure 2 is a schematic view showing a cross-sectional configuration of the above-described display device.

[0014] Figure 3 This is a plan view showing the sub-pixels provided in the display device of the first embodiment.

[0015] Figure 4 It is along Figure 3 The cross-sectional view of plane AB is shown.

[0016] Figure 5 This is a planar diagram showing the arrangement of the aforementioned sub-pixels.

[0017] Figure 6 This is a plan view showing the pattern of the electron transport layer for the red light-emitting layer disposed in the above-mentioned display device.

[0018] Figure 7 This is a plan view showing the pattern of the electron transport layer for the green light-emitting layer disposed in the above-mentioned display device.

[0019] Figure 8 This is a plan view showing the pattern of the electron transport layer for the blue light-emitting layer disposed in the above-mentioned display device.

[0020] Figure 9 This is a cross-sectional view used to illustrate the patterning method of the above-mentioned electron transport layer.

[0021] Figure 10 This is a cross-sectional view used to illustrate the patterning method of the above-mentioned electron transport layer.

[0022] Figure 11 This is a diagram showing an example of the energy levels of the Cd-based quantum dots in the aforementioned luminescent layer.

[0023] Figure 12 This is a diagram showing an example of the energy levels of the non-Cd quantum dots in the aforementioned luminescent layer.

[0024] Figure 13 This is a diagram showing an example of the energy levels of a QLED element disposed on the aforementioned display device.

[0025] Figure 14 This is a graph showing the band gap of the ZnO nanoparticles disposed on the aforementioned display device.

[0026] Figure 15 This is a plan view showing the arrangement of sub-pixels provided in the display device of the second embodiment.

[0027] Figure 16 It is along Figure 15 The cross-sectional view of plane AB is shown.

[0028] Figure 17 This is a plan view showing the pattern of the electron transport layer for the red light-emitting layer disposed in the above-mentioned display device.

[0029] Figure 18 is a plan view showing a pattern of an electron transport layer for a green light emitting layer provided in the above-described display device.

[0030] Figure 19 is a plan view showing a pattern of an electron transport layer for a blue light emitting layer provided in the above-described display device.

[0031] Figure 20 is a diagram showing an example of an energy level of the above-described light emitting layer.

[0032] Figure 21 is a diagram showing an example of an energy level of a modification of the above-described light emitting layer.

[0033] Figure 22 is a plan view showing an arrangement of sub-pixels provided in the display device of the third embodiment.

[0034] Figure 23 is a cross-sectional view along the face AB shown in Figure 22 .

[0035] Figure 24 is a plan view showing a pattern of an electron transport layer for a red light emitting layer and a green light emitting layer provided in the above-described display device.

[0036] Figure 25 is a plan view showing a pattern of an electron transport layer for a blue light emitting layer provided in the above-described display device.

[0037] Figure 26 is a diagram showing an example of an energy level of the above-described light emitting layer.

[0038] Figure 27 is a plan view showing another arrangement of sub-pixels provided in the above-described display device.

[0039] Figure 28 is a plan view showing a pattern of an electron transport layer for a blue light emitting layer provided in the above-described display device.

[0040] Figure 29 is a plan view showing a pattern of an electron transport layer for a green light emitting layer provided in the above-described display device.

[0041] Figure 30 is a plan view showing a pattern of an electron transport layer for a red light emitting layer provided in the above-described display device.

[0042] Figure 31 is a plan view showing still another arrangement of sub-pixels provided in the above-described display device.

[0043] Figure 32is a plan view showing another arrangement of the above-described sub-pixels.

[0044] Figure 33 is a plan view showing another arrangement of the above-described sub-pixels.

[0045] Figure 34 is a plan view showing another arrangement of the above-described sub-pixels. DETAILED DESCRIPTION

[0046] Hereinafter, "the same layer" means a layer formed in the same process (a film formation process), "a lower layer" means a layer formed in a process earlier than the layer to be compared, and "an upper layer" means a layer formed in a process later than the layer to be compared.

[0047] Figure 1 is a flowchart showing one example of a manufacturing method of a display device, Figure 2 is a schematic view showing a cross-sectional structure of a display device. As shown in Figure 1 With Figure 2 As shown in the drawing, in the manufacturing of the display device, first, a TFT (Thin Film Transistor) layer 4 is formed on a substrate 3 (step S1). Next, a pixel electrode layer 5 is formed (step S2). Next, an EL (Electro-Luminescence) layer 8 is formed (step S3). The EL layer 8 can be formed using, for example, a photolithography method, or can be formed using an evaporation method using a FMM (Fine Metal Mask). Next, a common electrode layer 9 is formed (step S4). Next, a sealing layer 10 is formed (step S5). Steps S1 to S4 are performed by a display device manufacturing apparatus (including a film formation apparatus for performing step S3).

[0048] Either one of the pixel electrode layer 5 and the common electrode layer 9 functions as a cathode electrode for injecting electrons, and an electron transport layer is formed between the cathode electrode and the EL layer 8. That is, in the case where the pixel electrode layer 5 is the cathode electrode, the electron transport layer is formed after step S2, and then step S3 is performed. In the case where the common electrode layer 9 is the cathode electrode, the electron transport layer is formed after step S3, and then step S4 is performed.

[0049] The substrate 3 can use glass, a resin such as polyimide, or the like. A barrier film such as silicon nitride can be formed in the glass or the resin to be used as the substrate 3.

[0050] The TFT layer 4 is provided with a semiconductor layer, a plurality of metal layers, and a plurality of insulating layers, and a plurality of TFTs (Thin Film Transistors) are formed. The control circuit of a light emitting element (for example, a light emitting diode) composed of the pixel electrode layer 5, the EL layer 8, and the common electrode layer 9 is formed in the TFT layer 4.

[0051] The pixel electrode layer 5 includes a plurality of pixel electrodes having light reflectivity, the EL layer 8 includes a plurality of light emitting layers (for example, quantum dot layer, organic light emitting layer), and the common electrode layer 9 includes a common electrode having light transmissivity.

[0052] The pixel electrode layer 5 is composed of, for example, a layer stack of ITO (Indium Tin Oxide) and Al (aluminum) or Ag (silver) or an alloy containing Ag. The common electrode layer 9 is composed of, for example, MgAg alloy (extremely thin film), ITO, IZO (Indium zinc Oxide), silver nanowire. In the pixel electrode layer 5 and the common electrode layer 9, the work functions are different. The pixel electrode layer 5 can be on the anode side (high voltage side), and the common electrode layer 9 can be on the cathode side (low voltage side), or the pixel electrode layer 5 can be on the cathode side (low voltage side), and the common electrode layer 9 can be on the anode side (high voltage side).

[0053] A plurality of light emitting elements composed of the pixel electrode layer 5, the EL layer 8, and the common electrode layer 9 are provided in the display region of the display device, and a driver that drives the TFT layer 4 and the like is provided outside the display region (bezel region).

[0054] In the case where the light emitting element is a QLED (Quantum dot Light Emitting Diode), holes and electrons are recombined in the light emitting layer by a driving current between the pixel electrode and the common electrode, and light (fluorescence) is emitted in the process in which excitons generated by the recombination migrate from the conduction band level to the valence band level of the quantum dot. The common electrode is light transmissive, and the pixel electrode is light reflective, and therefore the light emitted from the EL layer 8 is directed upward, and becomes top emission.

[0055] In the case where the light emitting element is an OLED (Organic Light Emitting Diode), holes and electrons are recombined in the light emitting layer by a driving current between the pixel electrode and the common electrode, and light is emitted in the process in which excitons generated by the recombination migrate to the ground state. The light emitting element is not limited to QLED, OLED, and can be an inorganic light emitting diode or the like.

[0056] The sealing layer 10 that is light transmissive includes an inorganic insulating film such as silicon nitride, and prevents penetration of foreign substances such as water and oxygen into the light emitting element.

[0057] (First Embodiment)

[0058] Figure 3 is a plan view that shows the sub-pixels SPr, SPg, SPb provided in the display device 2 of the first embodiment. Figure 4 is a plan view that shows the sub-pixels SPr, SPg, SPb provided in the display device 2 of the first embodiment. Figure 3A cross-sectional view of the illustrated face AB. Figure 5 is a plan view showing the arrangement of the sub-pixels SPr, SPg, SPb. Figure 6 is a plan view showing the pattern of the electron transport layer ETr provided in the display device 2 for the red light-emitting layer EMr. Figure 7 is a plan view showing the pattern of the electron transport layer ETg provided in the display device 2 for the green light-emitting layer EMg. Figure 7 is a plan view showing the pattern of the electron transport layer ETb provided in the display device 2 for the blue light-emitting layer EMb.

[0059] The display device 2 includes a sub-pixel SPr (first sub-pixel) for emitting light of red color (first color), a sub-pixel SPg (second sub-pixel) for emitting light of green color (second color), and a sub-pixel SPb (third sub-pixel) for emitting light of blue color (third color).

[0060] The sub-pixel SPr has a light-emitting region Lr, the sub-pixel SPg has a light-emitting region Lg, and the sub-pixel SPb has a light-emitting region Lb. Further, a non-light-emitting region NL is arranged so as to surround each of the light-emitting regions Lr, Lg, Lb.

[0061] A pixel electrode PEr, PEg, PEb is formed for each of the sub-pixels SPr, SPg, SPb, respectively. Further, a common electrode KE is commonly formed for the sub-pixels SPr, SPg, SPb. The common electrode KE can be a cathode. The pixel electrodes PEr, PEg, PEb can be anodes.

[0062] A red light-emitting layer EMr is formed between the pixel electrode PEr and the common electrode KE. A green light-emitting layer EMg is formed between the pixel electrode PEg and the common electrode KE. A blue light-emitting layer EMb is formed between the pixel electrode PEb and the common electrode KE.

[0063] Between the red light-emitting layer EMr and the common electrode KE, between the green light-emitting layer EMg and the common electrode KE, and between the blue light-emitting layer EMb and the common electrode KE, an electron transport layer ETr·ETg·ETb (third functional layer, second functional layer, first functional layer) is integrally formed continuously over the entire range of the sub-pixel SPr, the sub-pixel SPg, and the sub-pixel SPb.

[0064] The electron transport layer ETg (second functional layer) overlaps the pixel electrode PEg of the sub-pixel SPg (second sub-pixel) as a whole in plan view. The electron transport layer ETr (third functional layer) overlaps the pixel electrode PEr of the sub-pixel SPr (third sub-pixel) as a whole in plan view, and has an opening Org overlapping the inside of the peripheral end portion EDg of the pixel electrode PEg of the sub-pixel SPg (second sub-pixel) in plan view. That is, the central portion of the opening Org and the central portion of the pixel electrode PEg overlap in plan view. In addition, the electron transport layer ETr (third functional layer) overlaps the entire periphery of the peripheral end portion EDg of the pixel electrode PEg of the sub-pixel SPg (second sub-pixel) in plan view.

[0065] The electron transport layer ETr (third functional layer) has an opening Orb overlapping the inside of the peripheral end portion EDb of the pixel electrode PEb of the sub-pixel SPb (first sub-pixel) in plan view. That is, the central portion of the opening Orb and the central portion of the pixel electrode PEb overlap in plan view. In addition, the electron transport layer ETr (third functional layer) overlaps the entire periphery of the peripheral end portion EDb of the pixel electrode PEb of the sub-pixel SPb (first sub-pixel) in plan view.

[0066] The electron transport layer ETg (second functional layer) has an opening Ogr overlapping the inside of the peripheral end portion EDr of the pixel electrode PEr of the sub-pixel SPr (third sub-pixel) in plan view, and has an opening Ogb inside the peripheral end portion EDb of the pixel electrode PEb of the sub-pixel SPb (first sub-pixel). That is, the central portion of the opening Ogr and the central portion of the pixel electrode PEr overlap, and the central portion of the opening Ogb and the central portion of the pixel electrode PEb overlap. In addition, the electron transport layer ETg (second functional layer) overlaps the entire periphery of the peripheral end portion EDr of the pixel electrode PEr of the sub-pixel SPr (third sub-pixel) and the entire periphery of the peripheral end portion EDb of the pixel electrode PEb of the sub-pixel SPb (first sub-pixel).

[0067] The electron transport layer ETb (first functional layer) is adjacent to the electron transport layer ETg (second functional layer), and overlaps the entire pixel electrode PEb of the sub-pixel SPb (first sub-pixel) in plan view.

[0068] The electron transport layer ETb (first functional layer) has an opening Obr that overlaps the inner side of the peripheral end portion EDr of the pixel electrode PEr of the sub-pixel SPr (third sub-pixel) in plan view, and has an opening Obg that overlaps the inner side of the peripheral end portion EDg of the pixel electrode PEg of the sub-pixel SPg (second sub-pixel) in plan view. That is, the central portion of the opening Obr overlaps the central portion of the pixel electrode PEr in plan view, and the central portion of the opening Obg overlaps the central portion of the pixel electrode PEg in plan view. In addition, the electron transport layer ETb (first functional layer) overlaps the entire periphery of the peripheral end portion EDr of the pixel electrode PEr of the sub-pixel SPr (third sub-pixel) and the peripheral end portion EDg of the pixel electrode PEg of the sub-pixel SPg (second sub-pixel) in plan view.

[0069] In the case where the pixel electrode and the common electrode are close to the peripheral end portion of the pixel electrode, the electric field concentrates on the peripheral end portion of the pixel electrode and flows as excess current, the peripheral end portion of the pixel electrode deteriorates, and the light emitting region of the sub-pixel can be narrowed.

[0070] On the other hand, even if the functional layer is formed with an opening in the central portion of the pixel electrode, by forming a plurality of functional layers on the entire periphery of the pixel electrode in such a manner that they overlap in the center in plan view as described above, it is possible to prevent the common electrode from being close to the peripheral end portion of the pixel electrode. Therefore, it is possible to prevent the state in which the electric field concentrates on the peripheral end portion of the pixel electrode and the current flows excessively, and it is possible to prevent the narrowing of the light emitting region of the sub-pixel due to the deterioration of the peripheral end portion of the pixel electrode.

[0071] A hole transport layer HT is formed between the red light emitting layer EMr and the pixel electrode PEr, between the green light emitting layer EMg and the pixel electrode PEg, and between the blue light emitting layer EMb and the pixel electrode PEb.

[0072] The pixel electrodes PEr, PEg, PEb are respectively formed on an organic insulating film PF (a planarization film of polyimide or the like) that is the uppermost layer of the TFT layer 4, correspond respectively to the sub-pixels SPr, SPg, SPb, and are connected to the transistors 11 in contact holes CH formed in the TFT layer 4.

[0073] An edge cover EC that covers the edges of the pixel electrodes PEr, PEg, PEb is provided.

[0074] In this way, the common electrode KE is formed so as to straddle a plurality of sub-pixels SPr, SPg, SPb. Also, the red light emitting layer EMr, the green light emitting layer EMg, and the blue light emitting layer EMb are divided by being applied respectively to the pixel electrodes PEr, PEg, PEb, and are formed so as to extend also over a portion of the edge cover EC. The red light emitting layer EMr, the green light emitting layer EMg, and the blue light emitting layer EMb can contain quantum dots.

[0075] Three electron transport layers, ETr, ETg, and ETb, respectively suitable for the red emitting layer EMR, the green emitting layer EMG, and the blue emitting layer EMb, are formed between the common electrode KE and the red emitting layer EMR, the green emitting layer EMG, and the blue emitting layer EMb.

[0076] Each sub-pixel SPr, SPg, SPb is provided with pixel electrodes PER, PEg, PEb, which can apply a voltage different from the voltage applied to the pixel electrodes PER, PEg, PEb adjacent to each pixel electrode PER, PEg, PEb.

[0077] The edge cover EC is made of insulating material and is formed to cover the contact hole CH, the peripheral end of the pixel electrode PER EDr, the peripheral end of the pixel electrode PEg EDg, and the peripheral end of the pixel electrode PEb EDb.

[0078] Any one of the pixel electrodes PE, PEg, PRb, and the common electrode KE is visible light transmissive. The work functions of the pixel electrodes PE, PEg, and PRb are different from those of the common electrode KE. The pixel electrodes PE, PEg, and PEb are connected to transistor 11.

[0079] Hole injection layers (HILs) can also be placed between the red emitting layer EMR and the pixel electrode PER, the green emitting layer EMG and the pixel electrode PEg, and the blue emitting layer EMb and the pixel electrode PEb. Subpixels SPr, SPg, and SPb of various emitting colors are arranged adjacent to each other.

[0080] like Figure 6 As shown, the electron transport layer ETr suitable for the red emitting layer EMR is patterned to have an opening Org and an opening Orb. The opening Org is used to not cover the pixel electrode PEg corresponding to the green emitting layer EMR, and the opening Orb is used to not cover the pixel electrode PEb corresponding to the blue emitting layer EMR.

[0081] like Figure 7 As shown, the electron transport layer ETg suitable for the green light-emitting layer EMG is patterned to have an opening Ogr and an opening Ogb. The opening Ogr is used to not cover the pixel electrode PEr corresponding to the red light-emitting layer EMG, and the opening Ogb is used to not cover the pixel electrode PEb corresponding to the blue light-emitting layer EMG.

[0082] like Figure 8As shown, the electron transport layer ETb suitable for the blue emitting layer EMb is patterned with an opening Obg and an opening Obr. The opening Obg is used to avoid covering the pixel electrode PEg corresponding to the green emitting layer EMg, and the opening Obr is used to avoid covering the pixel electrode PEr corresponding to the red emitting layer EMr. This electron transport layer ETb completely overlaps with the pixel electrode PEb of the sub-pixel SPb (the first sub-pixel).

[0083] The electron transport layers ETr, ETg, and ETb constructed in this way are less prone to gaps and peeling because there are no protrusions with an angle of less than 180° on the inner side of the pattern in the display area where fine patterns need to be formed.

[0084] Thus, the electron transport layers ETr, ETg, and ETb are patterned over the entirety of the sub-pixels SPr, SPg, and SPb, resulting in a larger contact area with the substrate compared to electron transport layers patterned in isolated islands per sub-pixel. Consequently, the electron transport layers ETr, ETg, and ETb are difficult to peel off from the bottom.

[0085] Furthermore, in the isolated, quadrilateral island-shaped electron transport layer, the outer 270° portion of its corners is exposed during the processing step. In the electron transport layers ETr, ETg, ETb, which have quadrilateral openings Org, Orb, Ogr, Ogb, Obbr, and Obg patterned on the entire surface of the sub-pixels SPr, SPg, and SPb, the inner 90° of the corners of the openings Org, Orb, Ogr, Ogb, Obbr, and Obg are exposed during the processing step, thus suppressing peeling at the corners.

[0086] Figure 9 and Figure 10 It is a cross-sectional view used to illustrate the patterning method of the electron transport layers ETr, ETg, and ETb.

[0087] First, a photoresist containing ZnO (zinc oxide) is coated to a thickness of 20–100 nm. This photoresist contains a photosensitive resin 13 and nanoparticles 12 composed of ZnO (zinc oxide). Then, the solvent is evaporated, and the coated photoresist is pre-baked at 80–120 °C to allow it to dry. Next, it is heated to 10–1000 mJ / cm². 2 Under these conditions, the resist is exposed to UV (ultraviolet) light through mask 14. Then, it is developed with an alkaline solution, organic solvent, or water. In the case of a positive resist, the resist exposed to UV light partially dissolves. In the case of a negative resist, the resist not exposed to UV light partially dissolves. Then, the undissolved resist residue is formally fired at 100–200°C. If necessary, the formal firing process suppresses the release of UV gas from the photosensitive resin 13 during the operation of the EL layer 8.

[0088] The electron transport layer ETr, ETg, ETb thus formed contains the nanoparticles 12 of ZnO and the photosensitive resin 13. The conductivity of the photosensitive resin 13 is low under the driving voltage of the EL layer 8.

[0089] In the case where the red light emitting layer EMr, the green light emitting layer EMg, and the blue light emitting layer EMb contain CdSe-based nanoparticles, the size of the nanoparticles 12 of ZnO used is larger than that of the nanoparticles 12 used for the electron transport layer ETr, and the size of the nanoparticles 12 used for the electron transport layer ETg is larger than that of the nanoparticles 12 used for the electron transport layer ETb. In addition, the electron affinity becomes larger in the order of the nanoparticles 12 used for the electron transport layer ETr, the nanoparticles 12 used for the electron transport layer ETg, and the nanoparticles 12 used for the electron transport layer ETb. For example, the size of the nanoparticles 12 used for the electron transport layer ETr is larger than 6 nm, the size of the nanoparticles 12 used for the electron transport layer ETg is 6 nm, and the size of the nanoparticles 12 used for the electron transport layer ETb is 2 nm. As the nanoparticles used in the ETL layer, not only ZnO but also MgZnO nanoparticles to which Mg is added can be used. When Mg is added, the band gap can be made larger than that of ZnO by the amount of added Mg, and the electron affinity can be reduced. Thus, as the nanoparticles used in the ETL, a zinc oxide compound such as ZnO or MgZnO can be used.

[0090] As the hole transport material used for the hole transport layer HT, NiO nanoparticles or a photocurable hole transport material (X-F6-TAPC, QUPD, OTPD) can be used.

[0091] In order to manufacture the display device 2 having the conventional structure of the electron transport layers ETr, ETg, ETb, first, the edge cover EC is patterned on the AM substrate on which the anode pixel electrode is formed. Then, the hole injection layer and the hole transport layer HT are successively applied. Next, the red light emitting layer EMr, the green light emitting layer EMg, and the blue light emitting layer EMb are applied to the sub-pixels SPr, SPg, SPb, respectively, by a general method such as QD-PR, imprint, and the like.

[0092] Subsequently, the electron transport layer ETr pattern is formed by a photoresist containing nanoparticles, imprint, or the like. Then, the electron transport layer ETg pattern is formed by a photoresist containing nanoparticles, imprint, or the like. Next, the electron transport layer ETb pattern is formed by a photoresist containing nanoparticles, imprint, or the like. Then, the common electrode KE is formed. Then, the sealing layer is formed.

[0093] In order to manufacture the display device 2 having the reverse structure of the electron transport layer ETr, ETg, ETb, first, the edge cover EC is patterned on the AM substrate on which the cathode pixel electrode is formed. Then, the electron transport layer ETr pattern is formed by a photoresist containing nanoparticles, imprinting, or the like. Next, the electron transport layer ETg pattern is formed by a photoresist containing nanoparticles, imprinting, or the like. After that, the electron transport layer ETb pattern is formed by a photoresist containing nanoparticles, imprinting, or the like.

[0094] Then, the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb are coated by a general method such as QD-PR, imprinting, or the like, respectively, as the sub-pixels SPr, SPg, and SPb. Next, the hole transport layer HT and the hole injection layer are sequentially coated. Then, the common electrode KE is formed. Then, the sealing layer is formed. That is, both the normal structure and the reverse structure are sequentially stacked in the order of the electron transport layer ETb, the electron transport layer ETg, the electron transport layer ETr, and the cathode electrode from the light-emitting layer.

[0095] Figure 11 is a diagram showing an example of the energy levels of Cd-based quantum dots of the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb. In the case of the quantum dots of the red light-emitting layer EMr emitting red light of wavelength λ = 640 nm, the green light-emitting layer EMg emitting green light of wavelength λ = 530 nm, and the blue light-emitting layer EMb emitting blue light of wavelength λ = 450 nm, composed of Cd(Zn)Se, the LUMO (Lowest Unoccupied Molecular Orbital) of the red light-emitting layer EMr is -4.3 eV, and the HOMO (Highest Occupied Molecular Orbital) is -6.2 eV. Also, the LUMO of the green light-emitting layer EMg is -3.9 eV, and the HOMO is -6.2 eV. The LUMO of the blue light-emitting layer EMb is -3.4 eV, and the HOMO is -6.2 eV.

[0096] Figure 12 is a diagram showing an example of the energy levels of non-Cd-based quantum dots of the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb. In the case of the quantum dots of the red light-emitting layer EMr and the green light-emitting layer EMg composed of InP, and the quantum dots of the blue light-emitting layer EMb composed of ZnSe, the LUMO of the red light-emitting layer EMr is -3.6 eV, and the HOMO is -5.5 eV. Also, the LUMO of the green light-emitting layer EMg is -3.2 eV, and the HOMO is -5.5 eV. The LUMO of the blue light-emitting layer EMb is -2.9 eV, and the HOMO is -5.7 eV.

[0097] Figure 13 is a diagram showing an example of the energy level of the QLED element provided on the display device 2. The HOMO of the red light emitting layer EMr, the green light emitting layer EMg, and the blue light emitting layer EMb composed of the Cd-based quantum dot is -6.2 eV, the LUMO of the red light emitting layer EMr is -4.3 eV, the LUMO of the green light emitting layer EMg is -3.9 eV, and the LUMO of the blue light emitting layer EMb is -3.4 eV.

[0098] The LUMO of the electron transport layers ETr, ETg, ETb composed of ZnO is -3.9 eV, and the HOMO is -7.2 eV. The energy level of the common electrode KE composed of Al is -4.3 eV.

[0099] Therefore, the difference between the HOMO of the electron transport layers ETr, ETg, ETb and the LUMO of the red light emitting layer EMr is 2.9 eV, and the difference between the HOMO of the electron transport layers ETr, ETg, ETb and the LUMO of the blue light emitting layer EMb is 3.8 eV.

[0100] The LUMO of the hole transport layer HT composed of PVK (polyvinyl carbazole) is -2.2 eV, and the HOMO is 58 eV. The energy level of the hole injection layer composed of PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid)) is -5.4 eV. The energy level of the pixel electrodes PEr, PEg, PEb composed of ITO is -4.8 eV.

[0101] Figure 14 is a diagram showing the band gap of the ZnO nanoparticles of the electron transport layers ETr, ETg, ETb provided on the display device 2. The horizontal axis shows the particle diameter of the ZnO nanoparticles, and the vertical axis shows the band gap of the ZnO nanoparticles. As the particle diameter of the ZnO nanoparticles becomes smaller than 10 nm, the band gap of the ZnO nanoparticles increases exponentially from the band gap value of 3.4 eV of the bulk crystal.

[0102] Thus, the electron transport layers ETr, ETg, ETb are not isolated patterns, but are continuous patterns on the non-light emitting region NL, and have patterns of the openings Org, Orb, Ogr, Ogb, Obg, Obr at positions corresponding to the subpixels of other light emitting colors. Furthermore, the electron transport layers ETr, ETg, ETb are composed of materials most suitable for each subpixel SPr, SPg, SPb. Thus, the electron transport layers ETr, ETg, ETb composed of the most suitable materials in each subpixel SPr, SPg, SPb are joined to the red light emitting layer EMr, the green light emitting layer EMg, and the blue light emitting layer EMb, respectively. Therefore, a display device having a light emitting element with high light emitting efficiency can be realized.

[0103] In addition, the electron transport layers ETr, ETg, ETb are not isolated patterns, but are formed continuously over the entire sub-pixels SPr, SPg, SPb. Therefore, the electron transport layers ETr, ETg, ETb are less likely to be damaged or peeled off at the pixel edge portions. In addition, in a case where the functional layers are damaged or peeled off at the pixel edge portions, this can be a cause of uneven emission in the plane, but in a case where the functional layers are not isolated patterns but are formed continuously over the entire sub-pixels, such uneven emission can be suppressed.

[0104] In the example of the above-described embodiment, an example in which the electron transport layers ETr, ETg, ETb are formed between the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb and the common electrode KE is shown, but the present application is not limited thereto. The electron transport layers ETr, ETg, ETb can also be formed between the pixel electrodes PEr, PEg, PEb and the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb.

[0105] In the example of the above-described embodiment, an example in which the electron transport layers ETr, ETg, ETb are patterned is shown, but the present application is not limited thereto. Not only the electron transport layers ETr, ETg, ETb, but also the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb can be patterned in the same manner. In addition, a hole transport layer HT (fourth functional layer) can be formed in accordance with the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb, and can be patterned. The hole transport layer HT is formed on the side opposite to the electron transport layers ETr, ETg, ETb with respect to the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb. In patterning the hole transport layer HT, photolithography using a mixture of NiO nanoparticles and a photosensitive resin, or imprinting can be used. As the photocurable hole transport material, X-F6-TAPC, QUPD, OTPD, or the like can be used.

[0106] In a case where the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb are patterned, any one of the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb can overlap in the light-emitting region Lr, Lg, Lb, and can emit an undesirable color. Therefore, the openings of the patterned red light-emitting layer EMr, green light-emitting layer EMg, and blue light-emitting layer EMb are preferably wide.

[0107] In contrast, the electron transport layers ETr, ETg, ETb do not greatly affect the color of light emission even if the light-emitting regions Lr, Lg, Lb overlap. For this reason, it is preferable that the openings of the patterned red light-emitting layer EMr, the patterned green light-emitting layer EMg, and the patterned blue light-emitting layer EMb be larger than the openings of the patterned electron transport layers ETr, ETg, ETb.

[0108] (Second Embodiment)

[0109] Figure 15 is a plan view showing the arrangement of the sub-pixels SPr, SPg, SPb provided in the display device 2A of the second embodiment. Figure 16 is a cross-sectional view along the face AB shown in Figure 15 . Figure 17 is a plan view showing the pattern of the electron transport layer ETrA for the red light-emitting layer EMr provided in the display device 2A. Figure 18 is a plan view showing the pattern of the electron transport layer ETgA for the green light-emitting layer EMg provided in the display device 2A. Figure 7 is a plan view showing the pattern of the electron transport layer ETb for the blue light-emitting layer EMb provided in the display device 2A. The same reference numerals are attached to the same constituent elements as those described above, and the detailed description thereof is not repeated.

[0110] The electron transport layer ETrA is adapted to the red light-emitting layer EMr, is not patterned, and overlaps the entire pixel electrodes PEr, PEg, PEb as a whole.

[0111] The electron transport layer ETgA is adapted to the green light-emitting layer EMg, is patterned to have an opening Ogr not covering the pixel electrode PEr.

[0112] The electron transport layer ETb is adapted to the blue light-emitting layer EMb, is patterned to have an opening Obr not covering the pixel electrode PEr and an opening Obg not covering the pixel electrode PEg.

[0113] Furthermore, the electron transport layer ETb, the electron transport layer ETgA, and the electron transport layer ETrA are sequentially stacked. That is, the layers are sequentially stacked in the order of the electron transport layer ETb, the electron transport layer ETgA, the electron transport layer ETrA, and the cathode electrode from the light-emitting layer.

[0114] Figure 20is a diagram showing an example of energy levels of the light-emitting layer provided on the display device 2A. The HOMO of the electron-transporting layer ETrA, the electron-transporting layer ETgA, and the electron-transporting layer ETb is common and equal. The LUMO of the electron-transporting layer ETrA is -4.5 eV, which is lower than the LUMO of the red light-emitting layer EMr, which is -4.3 eV. The LUMO of the electron-transporting layer ETgA is -4.1 eV, which is lower than the LUMO of the green light-emitting layer EMg, which is -3.9 eV. The LUMO of the electron-transporting layer ETb is -3.7 eV, which is lower than the LUMO of the blue light-emitting layer EMb, which is -3.4 eV.

[0115] The first color emitted by the blue light-emitting layer EMb is blue, the third color emitted by the red light-emitting layer EMr is red, and the common electrode KE is a cathode. The electron-transporting layer ETb (first functional layer) and the electron-transporting layer ETrA (third functional layer) are formed between the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb and the common electrode KE. The electron-transporting layer ETrA is closer to the common electrode KE than the electron-transporting layer ETgA. The energy levels are sequentially lower in the order of the conduction band edge (LUMO) of the blue light-emitting layer EMb, which is -3.4 eV, the conduction band edge (LUMO) of the electron-transporting layer ETgA (second functional layer), which is -4.1 eV, and the conduction band edge (LUMO) of the electron-transporting layer ETrA (third functional layer), which is -4.5 eV.

[0116] Figure 21 is a diagram showing an example of energy levels of a modification example of the above-described light-emitting layer. The first color emitted by the blue light-emitting layer EMb is blue, the third color emitted by the red light-emitting layer EMr is red, and the second color emitted by the green light-emitting layer EMg is green. The pixel electrodes PEr, PEg, and PEb are cathodes. The electron-transporting layer ETb (first functional layer), the electron-transporting layer ETrA (third functional layer), and the electron-transporting layer ETgA (second functional layer) are formed between the red light-emitting layer EMr, the green light-emitting layer EMg, and the blue light-emitting layer EMb and the pixel electrodes PEr, PEg, and PEb. The electron-transporting layer ETgA (second functional layer) is closer to the pixel electrode than the electron-transporting layer ETb (first functional layer), and the electron-transporting layer ETrA (first functional layer) is closer to the pixel electrode than the electron-transporting layer ETgA (second functional layer). The energy levels are sequentially lower in the order of the conduction band edge (LUMO) of the blue light-emitting layer EMb, which is -3.4 eV, the conduction band edge (LUMO) of the electron-transporting layer ETb (first functional layer), which is -3.7 eV, the conduction band edge (LUMO) of the electron-transporting layer ETgA (second functional layer), which is -4.1 eV, and the conduction band edge (LUMO) of the electron-transporting layer ETrA (third functional layer), which is -4.5 eV.

[0117] (third embodiment)

[0118] Figure 22 is a plan view showing the arrangement of the sub-pixels SPr, SPg, SPb provided in the display device 2B of the third embodiment. Figure 23 is a cross-sectional view along the plane AB shown in Figure 22 . Figure 24 is a plan view showing the pattern of the electron transport layer ETrg provided in the display device 2B for the red light emitting layer EMr and the green light emitting layer EMg. Figure 25 is a plan view showing the pattern of the electron transport layer ETb provided in the display device 2B for the blue light emitting layer EMb. The same reference numerals are attached to the same constituent elements as those described above, and the detailed description thereof is not repeated.

[0119] The electron transport layer ETrg is adapted to the red light emitting layer EMr and the green light emitting layer EMg, and is not patterned, and overlaps the entire pixel electrodes PEr, PEg, PEb as a whole.

[0120] The electron transport layer ETb is adapted to the blue light emitting layer EMb, and is patterned to have the opening Obr not covering the pixel electrode PEr and the opening Obg not covering the pixel electrode PEg. Further, the electron transport layer ETb and the electron transport layer ETrg are stacked in this order. That is, the light emitting layer is stacked in the order of the electron transport layer ETb, the electron transport layer ETrg, and the cathode electrode in this order.

[0121] Thus, in the third embodiment, the same electron transport layer ETrg is in contact with the red light emitting layer EMr and the green light emitting layer EMg, which are different from each other.

[0122] Figure 26 is a diagram showing an example of the energy levels of the light emitting layers provided in the display device 2B. The HOMO of the electron transport layer ETrg and the electron transport layer ETb is common. The LUMO of the electron transport layer ETrg is -4.2 eV, which is lower than the LUMO of the green light emitting layer EMg, which is -3.9 eV. The LUMO of the electron transport layer ETb is -3.7 eV, which is lower than the LUMO of the blue light emitting layer EMb, which is -3.4 eV.

[0123] (fourth embodiment)

[0124] Figure 27 is a plan view showing the arrangement of the sub-pixels SPr, SPg, SPb provided in the display device 2C of the fourth embodiment. Figure 28 is a plan view showing the pattern of the electron transport layer ETbC provided in the display device 2C for the blue light emitting layer EMb. Figure 29This is a plan view showing the pattern of the electron transport layer ETgC for the green light-emitting layer EMG disposed in the display device 2C. Figure 30 This is a plan view showing the pattern of the electron transport layer ETrC for the red light-emitting layer EMR disposed in the display device 2C. The same reference numerals are used to denote the same constituent elements as described above, and these detailed descriptions are not repeated.

[0125] exist Figure 5 , 15 In the simple bar pixel array shown in Figure 22, each sub-pixel SPr, SPg, SPb is arranged with the same period and the same pattern. In contrast, Figure 27 The sub-pixels SPr, SPg, and SPb shown are arranged in a pentile pattern. In arrangements other than this simple strip pixel arrangement, the sub-pixels SPr, SPg, and SPb are arranged with different periods and different patterns.

[0126] like Figure 28 As shown, the opening Obg in the electron transport layer ETbC (first functional layer) that overlaps with the inner side of the periphery of the pixel electrode PEg of sub-pixel SPg (second sub-pixel) when viewed from above, and the opening Obr that overlaps with the inner side of the periphery of the pixel electrode PEr of sub-pixel SPr (third sub-pixel) when viewed from above, have different shapes.

[0127] like Figure 29 As shown, the opening Obg in the electron transport layer ETgC (second functional layer) that overlaps with the inner side of the periphery of the pixel electrode PEb of sub-pixel SPb (first sub-pixel) when viewed from above, and the opening Obr that overlaps with the inner side of the periphery of the pixel electrode PEr of sub-pixel SPr (third sub-pixel) when viewed from above have different shapes.

[0128] like Figure 30 As shown, the opening Org in the electron transport layer ETrC (third functional layer) that overlaps with the inner side of the periphery of the pixel electrode PEg of sub-pixel SPg (second sub-pixel) when viewed from above has a different shape than the opening Orb that overlaps with the inner side of the periphery of the pixel electrode PEb of sub-pixel SPb (first sub-pixel) when viewed from above.

[0129] Figure 31 This is a plan view showing the arrangement of sub-pixels SPr, SPg, and SPb in the display device 2D of the fourth embodiment. Figures 32 to 34 This is a plan view showing other arrangements of sub-pixels SPr, SPg, and SPb. The same reference numerals are used to label the same constituent elements as those described above, and these detailed descriptions are not repeated.

[0130] Figures 31 to 34The openings of the electron transport layers ETr, ETg, ETb shown as being patterned according to the arrangement of the subpixels SPr, SPg, SPb differ according to the emission color of the light-emitting layer corresponding to each electron transport layer ETr, ETg, ETb.

[0131] The present application is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the respective embodiments are also included in the technical scope of the present application. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments.

[0132] For example, the present application shows a case where three colors are mainly used in the above-described embodiments, and the length of the wavelength of the first color is the shortest, the length of the wavelength of the third color is the longest, the first color is blue, the second color is green, and the third color is red, but is not limited to this example. That is, it can also be applied to a case where only two colors without the third color are used, a case where the first color is shorter in wavelength than the second color (for example, a case where the first color is blue and the second color is red, a case where the first color is green and the second color is red, a case where the first color is blue and the second color is yellow, and the like), and the like.

[0133] Explanation of Reference Signs

[0134] 2 Display device

[0135] 4 TFT layer

[0136] 8 EL layer

[0137] SPr, SPg, SPb Subpixel (third subpixel, second subpixel, first subpixel)

[0138] PEr, PEg, PEb Pixel electrode

[0139] EMr Red light-emitting layer

[0140] EMg Green light-emitting layer

[0141] EMb Blue light-emitting layer

[0142] EDR, EDg, Edb Peripheral edge portion (of pixel electrode)

[0143] KE Common electrode

[0144] ETr, ETg, Etb Electron transport layer (third functional layer, second functional layer, first functional layer)

[0145] HT Hole transport layer (fourth functional layer)

[0146] Org, Orb, Ogr, Ogb, Obg, Obr opening

[0147] Lr, Lg, Lb light emitting region

[0148] NL non-light emitting region

[0149] EC edge cover

Claims

1. A display device, characterized by comprising: Possessing: a plurality of subpixels arranged in a matrix, and having a first subpixel that emits light of a first color, a second subpixel that emits light of a second color, and a third subpixel that emits light of a third color; a pixel electrode formed for each of the plurality of subpixels; a common electrode formed across the plurality of subpixels in plan view; a light-emitting layer formed between the pixel electrode and the common electrode; a first functional layer formed between the light-emitting layer and the pixel electrode or between the light-emitting layer and the common electrode, and formed continuously across the plurality of subpixels in plan view as a whole; and a second functional layer formed between the light-emitting layer and the pixel electrode or between the light-emitting layer and the common electrode, and formed continuously across the plurality of subpixels in plan view as a whole, the second subpixel emits light of the second color having a longer wavelength than the first color, the second functional layer overlaps the pixel electrode of the second subpixel as a whole in plan view, the first functional layer overlaps the pixel electrode of the first subpixel as a whole in plan view, and has an opening that overlaps an inner side of a peripheral edge portion of the pixel electrode of the second subpixel in plan view.

2. The display device of claim 1, wherein, the third subpixel emits light of the third color having a longer wavelength than the second color, the first functional layer has an opening that overlaps an inner side of a peripheral edge portion of the pixel electrode of the third subpixel in plan view.

3. The display device of claim 1, wherein the third subpixel emits light of the third color having a longer wavelength than the second color, the second functional layer overlaps the pixel electrode of the first subpixel as a whole and the pixel electrode of the third subpixel as a whole in plan view.

4. The display device of claim 1, wherein the third subpixel emits light of the third color having a longer wavelength than the second color, the second functional layer has an opening that overlaps an inner side of a peripheral edge portion of the pixel electrode of the first subpixel and an inner side of a peripheral edge portion of the pixel electrode of the third subpixel in plan view.

5. The display device of claim 1, wherein the third subpixel emits light of the third color having a longer wavelength than the second color, the second functional layer overlaps the pixel electrode of the first subpixel as a whole in plan view, and has an opening that overlaps an inner side of a peripheral edge portion of the pixel electrode of the third subpixel in plan view.

6. The display device of claim 1, wherein the third subpixel emits light of the third color having a longer wavelength than the second color, the second functional layer overlaps the pixel electrode of the third subpixel as a whole in plan view, and has an opening that overlaps an inner side of a peripheral edge portion of the pixel electrode of the first subpixel in plan view.

7. The display device according to any one of claims 2 to 6, wherein Further possessing a third functional layer formed between the light-emitting layer and the pixel electrode or between the light-emitting layer and the common electrode, formed continuously across the plurality of subpixels in plan view as a whole, the third functional layer overlaps the pixel electrode of the third subpixel as a whole in plan view.

8. The display device of claim 7, wherein, the first functional layer is adjacent to at least one of the second functional layer or the third functional layer.

9. The display device of claim 7, wherein, the third functional layer overlaps the pixel electrode of the first subpixel as a whole and the pixel electrode of the second subpixel as a whole in plan view.

10. The display device of claim 7, wherein, The third functional layer has an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the first sub-pixel in plan view, and overlapping the pixel electrode of the second sub-pixel as a whole in plan view.

11. The display device of claim 7, wherein The third functional layer has an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the second sub-pixel in plan view, and overlapping the pixel electrode of the first sub-pixel as a whole in plan view.

12. The display device of claim 7, wherein, The third functional layer has an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the first sub-pixel in plan view, and overlapping the inner side of the peripheral end portion of the pixel electrode of the second sub-pixel in plan view.

13. The display device according to any one of claims 1 to 6, wherein The first functional layer and the second functional layer are electron transport layers.

14. The display device according to any one of claims 1 to 6, wherein The first functional layer and the second functional layer are hole transport layers.

15. The display device of any one of claims 1 to 6, wherein, The first color is blue, the second color is red, The common electrode is a cathode, The first functional layer and the second functional layer are electron transport layers, and are formed between the light-emitting layer and the common electrode. The second functional layer is located closer to the common electrode than the first functional layer, The conduction band edge of the light-emitting layer of the first sub-pixel, the conduction band edge of the first functional layer, the conduction band edge of the second functional layer, and the conduction band edge of the third functional layer are sequentially lower in order of energy level.

16. The display device of claim 7, wherein The first color is blue, the second color is green, and the third color is red, The common electrode is a cathode, The first functional layer, the second functional layer, and the third functional layer are electron transport layers, and are formed between the light-emitting layer and the common electrode. The second functional layer is located closer to the common electrode than the first functional layer, and the third functional layer is located closer to the common electrode than the second functional layer, The conduction band edge of the light-emitting layer of the first sub-pixel, the conduction band edge of the first functional layer, the conduction band edge of the second functional layer, and the conduction band edge of the third functional layer are sequentially lower in order of energy level.

17. The display device of any one of claims 1 to 6, wherein, The first color is blue, the second color is red, The common electrode is a cathode, The first functional layer and the second functional layer are electron transport layers, and are formed between the light-emitting layer and the pixel electrode. The second functional layer is located closer to the pixel electrode than the first functional layer, The conduction band edge of the light-emitting layer of the first sub-pixel, the conduction band edge of the first functional layer, and the conduction band edge of the second functional layer are sequentially lower in order of energy level.

18. The display apparatus of claim 7, wherein The first color is blue, the second color is green, and the third color is red, The pixel electrode is a cathode, The first functional layer, the second functional layer, and the third functional layer are electron transport layers, and are formed between the light-emitting layer and the pixel electrode. The second functional layer is located closer to the pixel electrode than the first functional layer, and the third functional layer is located closer to the pixel electrode than the second functional layer, The conduction band edge of the light-emitting layer of the first sub-pixel, the conduction band edge of the first functional layer, the conduction band edge of the second functional layer, and the conduction band edge of the third functional layer are sequentially lower in order of energy level.

19. The display device of claim 1, wherein The first functional layer overlaps the entire circumference of the peripheral end portion of the pixel electrode of the second sub-pixel when viewed from above, The second functional layer overlaps the entire circumference of the peripheral end portion of the pixel electrode of the first sub-pixel when viewed from above.

20. The display device of claim 7, wherein, The first functional layer overlaps the entire circumference of the peripheral end portion of the pixel electrode of the second sub-pixel and the entire circumference of the peripheral end portion of the pixel electrode of the third sub-pixel when viewed from above, The second functional layer overlaps the entire circumference of the peripheral end portion of the pixel electrode of the first sub-pixel and the entire circumference of the peripheral end portion of the pixel electrode of the third sub-pixel when viewed from above. The third functional layer overlaps the entire circumference of the peripheral end portion of the pixel electrode of the first sub-pixel and the entire circumference of the peripheral end portion of the pixel electrode of the second sub-pixel when viewed from above.

21. The display device of claim 2, wherein The first functional layer has an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the second sub-pixel when viewed from above and an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the third sub-pixel when viewed from above.

22. The display device of claim 12, wherein, The third functional layer has an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the second sub-pixel when viewed from above and an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the first sub-pixel when viewed from above.

23. The display apparatus of claim 7, wherein The first functional layer, the second functional layer, and the third functional layer are each an electron transport layer containing zinc oxide compound nanoparticles, The particle diameters of the zinc oxide compound nanoparticles contained in the first functional layer, the zinc oxide compound nanoparticles contained in the second functional layer, and the zinc oxide compound nanoparticles contained in the third functional layer are sequentially larger, and the electron affinities are sequentially larger.

24. A display device comprising: a pixel electrode formed for each sub-pixel; a common electrode; a light-emitting layer formed between the pixel electrode and the common electrode; and a first functional layer and a second functional layer formed between the light-emitting layer and the pixel electrode or between the light-emitting layer and the common electrode, continuously formed across a plurality of the sub-pixels, the sub-pixels including a first sub-pixel emitting light of a first color and a second sub-pixel emitting light of a second color having a longer wavelength than the first color, the second functional layer overlapping the entire pixel electrode of the second sub-pixel when viewed from above, the first functional layer overlapping the entire pixel electrode of the first sub-pixel when viewed from above and having an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the second sub-pixel when viewed from above, the display device characterized in that the display device further comprises a fourth functional layer formed between the light-emitting layer and the pixel electrode or between the light-emitting layer and the common electrode on the side opposite to the first functional layer with respect to the light-emitting layer, the fourth functional layer overlapping the entire pixel electrode of the first sub-pixel when viewed from above and having an opening overlapping the inner side of the peripheral end portion of the pixel electrode of the second sub-pixel when viewed from above.

25. The display device of claim 24, wherein, The first functional layer and the second functional layer are electron transport layers, The fourth functional layer is a hole transport layer.

Images