Display device

Abstract

A first light-emitting element (D1) provided in a display device (1) of the present disclosure has, in this order, a first electrode (E1), a first light-emitting layer (L1) comprising a first light-emitting material (Q1), a semi-translucent first lower metal layer (12), a first intermediate layer (14), a semi-translucent first upper metal layer (16), and a first light extraction surface (S1). A resonance structure is formed between the first lower metal layer (12) and the first upper metal layer (16), and the resonance structure enhances light having an emission peak wavelength of the first light-emitting material (Q1) and traveling in a front direction orthogonal to the first light extraction surface.

Description

Technical Field

[0001] This disclosure relates to display devices. Background Technology

[0002] Patent document 1 discloses a light-emitting device in which the organic EL portion has a microcavity structure and a lens on the light extraction surface.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2011-29172 Summary of the Invention The technical problem to be solved by the present invention In light-emitting elements and display devices equipped with light-emitting elements, it is required to increase the brightness of the front side.

[0004] Technical solutions for solving technical problems The display device disclosed herein is configured to include a first light-emitting element, the first light-emitting element comprising: a first electrode; a first light-emitting element located above the first electrode and including a first light-emitting material; and a first light-extracting surface located above the first light-emitting layer. The first light-emitting element includes: a semi-transparent first lower metal layer and a semi-transparent first upper metal layer located between the first light-emitting layer and the first light-extracting surface; and a first intermediate layer located between the first lower metal layer and the first upper metal layer. A resonant structure is formed between the first lower metal layer and the first upper metal layer, the resonant structure enhancing light having the emission peak wavelength of the first light-emitting material and traveling in a forward direction orthogonal to the first light-extracting surface. Beneficial effects According to the configuration of this disclosure, a vivid image display can be achieved in a display device equipped with a light-emitting element. Attached Figure Description

[0005] Figure 1 This is a plan view illustrating an example of the schematic configuration of a display device according to one embodiment of the present disclosure.

[0006] Figure 2 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure.

[0007] Figure 3 It is shown in magnification Figure 2 The cross-sectional view of the first intermediate layer and the buffer layer is shown.

[0008] Figure 4 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure.

[0009] Figure 5 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure.

[0010] Figure 6 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure. Detailed Implementation

[0011] <First Implementation Method> Figure 1 This is a plan view illustrating an example of the schematic configuration of a display device according to an embodiment of the present disclosure. Figure 1 As shown, the display device 1 of this disclosure includes at least one light-emitting element DX. The display device 1 includes, for example, a display area DA, which is provided with a plurality of sub-pixels PX; and a border area NA, which is provided with a driving circuit DC for driving the display area DA, wherein at least one of the plurality of sub-pixels PX has a light-emitting element DX and a pixel circuit PC.

[0012] Figure 2 This is a cross-sectional view illustrating an example of the schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure. For example... Figure 2 As shown, the display device 1 of this disclosure includes a first light-emitting element D1, which has a first electrode E1; a first light-emitting layer L1 located above the first electrode E1 and containing a first light-emitting material Q1; and a first light-extracting surface S1 located above the first light-emitting layer L1. The first light-emitting element D1 also includes a semi-transparent first lower metal layer 12 and a semi-transparent first upper metal layer 16 located between the first light-emitting layer L1 and the first light-extracting surface S1, and a first intermediate layer 14 located between the first lower metal layer 12 and the first upper metal layer 16. Here, a resonant structure is formed between the first lower metal layer 12 and the first upper metal layer 16, which enhances light having the emission peak wavelength of the first light-emitting material Q1 and traveling in a forward direction orthogonal to the first light-extracting surface. In this disclosure, "between a certain layer and other layers located above that layer" means between the upper surface of the certain layer and the lower surface of the other layers. The aforementioned "front direction" refers to the front direction of the display device 1, and also the front direction of the first light-emitting element D1.

[0013] Based on the above configuration, the resonant structure between the first lower metal layer 12 and the first upper metal layer 16 can improve the light extraction efficiency of the first light-emitting element D1, and also improve the front brightness and color purity of the first light-emitting element D1. Therefore, the sharpness of the image displayed by the display device 1 can be improved.

[0014] Specifically, the first intermediate layer 14 is transparent, and the top of the first lower metal layer 12 and the bottom of the first upper metal layer function as light-reflecting surfaces. Thus, a resonant structure is formed between the first lower metal layer 12 and the first upper metal layer 16. For example, if the distance between the first lower metal layer 12 and the first upper metal layer 16 is set as D [nm], and the peak emission wavelength of the first luminescent material Q1 is set as λ [nm], then D ≈ λ × 0.2 [nm]. As an error tolerance, for example, 10 [nm] can be allowed, in which case D ≤ λ × 0.2 + 10 [nm] and D ≥ λ × 0.2 - 10 [nm].

[0015] The full width at half maximum (FWHM) of the emission spectrum of the first luminescent material Q1 is preferably less than one-tenth of the emission peak wavelength of the first luminescent material Q1. This further improves the frontal brightness and color purity of the first luminescent element D1. The first luminescent material Q1 includes, for example, luminescent quantum dots capable of emitting light through the recombination of holes and electrons.

[0016] In this disclosure, "quantum dot" refers to a dot with a maximum width of 100 nm or less. The shape of the quantum dot is not particularly limited as long as it meets the aforementioned maximum width requirement, and is not limited to a spherical three-dimensional shape (a circular cross-sectional shape). For example, it can be a polygonal cross-sectional shape, a rod-shaped three-dimensional shape, a dendritic three-dimensional shape, a three-dimensional shape with uneven surfaces, or a combination of these shapes. In this embodiment, the quantum dot is, for example, a semiconductor microparticle with a particle size of 100 nm or less, capable of being a crystal of group II-VI semiconductor compounds such as MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, and / or a crystal of group III-V semiconductor compounds such as GaAs, GaP, InN, InAs, InP, InSb, and / or a crystal of semiconductor compounds such as Si, Ge. Alternatively, quantum dots can also have a core / shell structure, for example, consisting of a semiconductor crystal as the core and a shell material with a large band gap covering the core. Furthermore, the shell does not need to completely cover the core; it only needs to be formed on a portion of the core.

[0017] The first electrode E1 is light-reflective, and a resonant structure can be formed between the first electrode E1 and the first lower metal layer 12. This resonant structure enhances the light with the emission peak wavelength of the first light-emitting material Q1 that travels in the forward direction. As a result, the light extraction efficiency of the first light-emitting element D1 can be further improved, and the front brightness and color purity of the first light-emitting element D1 can be further improved.

[0018] When the first electrode E1 functions as the anode, at least one of the first lower metal layer 12 and the first upper metal layer 16 functions as the cathode. Alternatively, when the first electrode E1 functions as the cathode, at least one of the first lower metal layer 12 and the first upper metal layer 16 can function as the anode. Therefore, an additional electrode opposite to the first electrode E1 does not need to be provided on the first light-emitting element D1, thus reducing the number of manufacturing steps for the first light-emitting element D1.

[0019] The brightness of the first light-emitting element D can be less than 50% of the brightness in the direction forming an angle of 40° or more with respect to the frontal direction. This further improves the frontal brightness and color purity of the first light-emitting element D1.

[0020] The first intermediate layer 14 can be conductive. In this case, the first lower metal layer 12 and the first upper metal layer 16 are electrically connected via the first intermediate layer 14. When the first electrode E1 functions as an anode, the first lower metal layer 12, the first intermediate layer 14, and the first upper metal layer 16 cooperate to function as a cathode, thereby reducing the cathode's resistance. Furthermore, when the first electrode E1 functions as a cathode, the first lower metal layer 12, the first intermediate layer 14, and the first upper metal layer 16 cooperate to function as an anode, thereby reducing the anode's resistance. This reduction in resistance is particularly beneficial when the first lower metal layer 12 and / or the first upper metal layer 16 are included in a common electrode spanning multiple light-emitting elements.

[0021] Alternatively, the first intermediate layer 14 can also be insulating.

[0022] The composition and thickness of the first lower metal layer 12 and the first upper metal layer 16 can be the same or different. For example, a thin film containing more than 50% silver (Ag), aluminum (Al), and gold (Au) by volume, with a thickness of 1 nm to 40 nm, exhibits semi-transparency. Alternatively, a thin film containing more than 50% alkali metals such as lithium (Li) and alkaline earth metals such as magnesium (Mg) by volume, with a thickness of 1 nm to 40 nm, also exhibits semi-transparency. These semi-transparent metal films can be used in the first lower metal layer 12 and the first upper metal layer 16 through any combination.

[0023] The first lower metal layer 12 may comprise aluminum (Al). This configuration is advantageous when the first electrode E1 is the anode. Aluminum is known as a material with low electron affinity and favorable for electron injection. The thickness of the first lower metal layer 12 can be less than 10 nm. This configuration is advantageous when the first lower metal layer 12 is electrically connected to the first upper metal layer 16. Even aluminum, which has high light reflectivity, exhibits semi-transparency when its thickness is less than 10 nm.

[0024] The first light-emitting element D1 may selectively have one or more of the following between the anode and the first light-emitting layer L1: a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer. The first light-emitting element D1 may selectively have one or more of the following between the cathode and the first light-emitting layer L1: an electron injection layer, an electron transport layer ETL, and a hole blocking layer.

[0025] The display device 1 disclosed herein may also include a second light-emitting element D2, which has a second electrode E2; a second light-emitting layer L2 located above the second electrode E2 and containing a second light-emitting material Q2; and a second light-extracting surface S2 located above the second light-emitting layer L2. The second light-emitting element D2 further includes: a semi-transparent second lower metal layer 22 and a semi-transparent second upper metal layer 26 located between the second light-emitting layer L2 and the second light-extracting surface S2; and a second intermediate layer 24 located between the second lower metal layer 22 and the second upper metal layer 26. Here, a resonant structure is formed between the second lower metal layer 22 and the second upper metal layer 26, which enhances light having the emission peak wavelength of the second light-emitting material Q2 and traveling in the forward direction. The first light-emitting element D1 and the second light-emitting element D2 can be adjacent via a dam BK. The first light-emitting layer L1 and the second light-emitting layer L2 can emit light of different colors.

[0026] The display device 1 disclosed herein may have a third light-emitting element D3, which has a third light-emitting layer L3 that emits light of a different color than the first light-emitting layer L1 and the second light-emitting layer L2. The third light-emitting element D3 may have the same configuration as the first light-emitting element D1, for example, it may have: a third electrode E3; a third light-emitting layer L3 located above the third electrode and containing a third light-emitting material Q3; and a third light-extracting surface S3 located above the third light-emitting layer. The third light-emitting element D3 may also include a semi-transparent third lower metal layer 32 and a semi-transparent third upper metal layer 36 located between the third light-emitting layer L3 and the third light-extracting surface S3, and a third intermediate layer 34 located between the third lower metal layer 32 and the third upper metal layer 36. Here, a resonant structure is formed between the third lower metal layer 32 and the third upper metal layer 36, which enhances the light having the emission peak wavelength of the third light-emitting material Q3 and traveling in the forward direction. The third light-emitting element D3 can be adjacent to the second light-emitting element D2 across the embankment BK.

[0027] The embankment BK can function as an edge shield, covering the edges of the first electrode E1 and the second electrode E2. The second electrode E2, the second lower metal layer 22, the second intermediate layer 24, and the second upper metal layer 26 can be made of the same material as the first electrode E1, the first lower metal layer 12, the first intermediate layer 14, and the first upper metal layer 16.

[0028] The display device 1 of this disclosure may also include a first relay metal layer 42 and a second relay metal layer 46 that overlap with the aforementioned embankment BK when viewed from above. Alternatively, the first lower metal layer 12 and the second lower metal layer 22 may be connected via the first relay metal layer 42, and the first upper metal layer 16 and the second upper metal layer 26 may be connected via the second relay metal layer 46. The first relay metal layer 42 may be made of the same material as the first lower metal layer 12 and the second lower metal layer 22, or it may be continuous with the first lower metal layer 12 and the second lower metal layer 22. The second relay metal layer 46 may be made of the same material as the first upper metal layer 16 and the second upper metal layer 26, or it may be continuous with the first upper metal layer 16 and the second upper metal layer 26.

[0029] The peak emission wavelength of the first light-emitting material Q1 can be greater than the peak emission wavelength of the second light-emitting material Q2. In this case, the distance between the first lower metal layer 12 and the first upper metal layer 16 is greater than the distance between the second lower metal layer 22 and the second upper metal layer 26. Therefore, based on the peak emission wavelength, i.e., based on color, the cavity effect in the first light-emitting element D1 and the second light-emitting element D2 is optimized. Furthermore, the white brightness of the display device 1 can be improved. Also, the peak emission wavelength of the second light-emitting material Q2 can be greater than the peak emission wavelength of the third light-emitting material Q3. In this case, the distance between the second lower metal layer 22 and the second upper metal layer 26 is greater than the distance between the third lower metal layer 32 and the third upper metal layer 36.

[0030] For example, the first luminescent material Q1 may emit red light, the second luminescent material Q2 may emit green light, and the third luminescent material Q3 may emit blue light. The thickness of the first intermediate layer 14 may be greater than the thickness of the second intermediate layer 24, and the thickness of the second intermediate layer 24 may be greater than the thickness of the third intermediate layer 34. For example, the first intermediate layer 14 may be formed with a thickness of 126 nm, the second intermediate layer 24 with a thickness of 106 nm, and the third intermediate layer with a thickness of 92 nm from a photocurable resin.

[0031] The distance between the first lower metal layer 12 and the first upper metal layer 16, and the distance between the second lower metal layer 22 and the second upper metal layer 26, are preferably 200 nm or less. This shortens the optical path difference between the interfering light rays, achieving a sufficient resonance effect. Similarly, for light-emitting elements other than the first light-emitting element D1 and the second light-emitting element D2, regardless of color, the distance between the lower metal layer and the upper metal layer is preferably 200 nm or less.

[0032] The display device 1 disclosed herein may also include a buffer layer 44 disposed between the first relay metal layer 42 and the second relay metal layer 46. The thickness of the buffer layer 44 above the upper surface of the embankment BK can be such that it does not enhance light having the emission peak wavelength of the first light-emitting material Q1 and traveling in the forward direction, and light having the emission peak wavelength of the second light-emitting material Q2 and traveling in the forward direction, preferably a reduced thickness. This reduces light leakage (crosstalk) between the first light-emitting element D1 and the second light-emitting element D2. By reducing crosstalk, image display blurring can be reduced. The buffer layer 44 can be made of the same material as the first intermediate layer 14 and the second intermediate layer 24, or it can be continuous with the first intermediate layer 14 and the second intermediate layer 24.

[0033] Figure 3 It is shown in magnification Figure 2 The diagram shows a cross-sectional view of the first intermediate layer and the buffer layer. Figure 3 As shown, the thickness Z1 of the buffer layer 44 in the cross section parallel to the normal of the first electrode E1 and passing through the slope of the embankment BK can be greater than the thickness Z2 of the first intermediate layer 14 in the cross section parallel to the normal of the first electrode E1 and passing through the central part of the first electrode E1.

[0034] The thickness Z2 is preferably formed on the inclined surface of the embankment BK, between the first relay metal layer 42 and the second relay metal layer 46, to enhance the resonant structure of light having the emission peak wavelength of the first luminescent material Q1 and traveling in the forward direction. For example, regarding the emission peak wavelength of the first luminescent material Q1, the thickness Z1 above the inclined surface can be the length of an m-th resonator or a value close to it, and the thickness Z2 above the first electrode E1 can be the length of an n-th resonator or a value close to it. Here, m and n are natural numbers, where m > n.

[0035] (Resonator length) When the resonant structure between the lower and upper metal layers fully enhances the light, the following equation (1) holds; when it fully weakens the light, the following equation (2) holds.

[0036] [Mathematical Expression 1] [Mathematical Expression 2] Here, m is the order of resonance, and θ D The phase shift θ is caused by reflection from the lower metal layer. U The phase shift is caused by reflection from the upper metal layer, where λ is the peak wavelength of the light, and n is the refractive index of the intermediate layer located between the lower and upper metal layers. Additionally, d is the distance from the upper surface of the lower metal layer to the lower surface of the upper metal layer, and θ is the thickness of the intermediate layer. Let the phase shift θ be... D θ U This makes the degree m in the above equation (1) a natural number when the distance d is positive, that is, the following equation (3) holds.

[0037] [Mathematical Expression 3] Let the value of the distance d when the condition (1) for constructive interference of the above order m is true be D. m Let the distance d be the value of the condition (2) for the above destructive interference, which is expressed in terms of the number of times m, when it holds. m In the resonant structure that enhances the peak wavelength λ of light, equation (4-1) holds, preferably equation (4-2), and more preferably equation (4-3). When generalized using a natural number k, equation (4-4) holds, and the larger k is, the more preferred. On the other hand, in the resonant structure that weakens the peak wavelength λ of light, equation (5-1) holds, preferably equation (5-2), and more preferably equation (5-3). When generalized using a natural number k, equation (5-4) holds, and the larger k is, the more preferred.

[0038] [Mathematical Expression 4] [Mathematical Expression 5] This disclosure can be quantitatively understood by applying the mathematical formulas described above.

[0039] (Manufacturing method) Refer again Figure 2In one example of a method for manufacturing a display device according to an embodiment of this disclosure, a substrate Sb is prepared, and a plurality of pixel electrodes, including a first electrode E1 and a second electrode E2, are formed on the substrate Sb. A dam BK is formed between the pixel electrodes. Next, one or more of a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer are selectively formed on the plurality of pixel electrodes. Furthermore, a first light-emitting layer L1 is formed above the first electrode E1, a second light-emitting layer L2 is formed above the second electrode E2, and light-emitting layers are also appropriately formed above the other pixel electrodes. Then, one or more of an electron injection layer, an electron transport layer ETL, and a hole blocking layer are selectively formed on the plurality of light-emitting layers including the first light-emitting layer L1 and the second light-emitting layer L2 (step S70).

[0040] Next, a first lower metal layer 12, a second lower metal layer 22, and a first relay metal layer 42 are formed. The first lower metal layer 12, the second lower metal layer 22, and the first relay metal layer 42 can be formed separately or simultaneously.

[0041] Next, a first intermediate layer 14, a second intermediate layer 24, and a buffer layer 44 are formed (step S90). The first intermediate layer 14, the second intermediate layer 24, and the buffer layer 44 can be formed by any method; they can be formed separately or simultaneously. For example, using a halftone mask or a grayscale mask, multiple layers of different thicknesses can be formed simultaneously from the photoresist material. For example, multiple layers of different thicknesses can be formed sequentially using different vapor deposition masks.

[0042] One or more of the first intermediate layer 14, the second intermediate layer 24, the buffer layer 44, and the layers formed between the first lower metal layer 12 and the first upper metal layer 16 may be a multilayer stack. For example, the buffer layer 44 may include layers formed simultaneously with the first intermediate layer 14 and layers formed simultaneously with the second intermediate layer 24.

[0043] Next, a first upper metal layer 16, a second upper metal layer 26, and a second relay metal layer 46 are formed. The first upper metal layer 16, the second upper metal layer 26, and the second relay metal layer 46 can be formed separately or simultaneously.

[0044] <Second Implementation Method> Figure 4 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure. For example... Figure 4 As shown, the first relay metal layer 42 and the second relay metal layer 46 can also be in contact above the embankment BK. In this case, the first lower metal layer 12 and the first upper metal layer 16 are electrically connected via the first relay metal layer 42 and the second relay metal layer 46.

[0045] According to the above configuration, regardless of whether the first intermediate layer 14 is conductive or insulating, the first lower metal layer 12 and the first upper metal layer 16 are electrically connected to each other. Therefore, the first lower metal layer 12 and the first upper metal layer 16 cooperate to function as a cathode (or anode), thereby reducing the resistance of the cathode (or anode).

[0046] Furthermore, since the first intermediate layer 14 and the second intermediate layer 24 are disconnected at least on the embankment BK, light leakage (crosstalk) between the first light-emitting element D1 and the second light-emitting element D2 can be reduced. By reducing crosstalk, the blurring of the image display can be reduced. Crosstalk between the second light-emitting element D2 and the third light-emitting element D3 can also be reduced.

[0047] <Third Implementation Method> Figure 5 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure. For example... Figure 5 As shown, the first light-emitting element D1 may also include a semi-transparent first inner metal layer 10 between the first light-emitting layer L1 and the first lower metal layer 12. A light-transmitting layer 11 made of the same material as the first intermediate layer 14 may be disposed between the first inner metal layer 10 and the first lower metal layer 12. Here, a resonant structure that enhances the emission peak wavelength of the first light-emitting material Q1 may be formed between the first inner metal layer 10 and the first lower metal layer 12.

[0048] Furthermore / or, the first light-emitting element D1 may also include a semi-transparent first outer metal layer 18 between the first upper metal layer 16 and the first light extraction surface S1. A light-transmitting layer 17 made of the same material as the first intermediate layer 14 may be disposed between the first upper metal layer 16 and the first outer metal layer 18. Here, a resonant structure that enhances the light emission peak wavelength of the first light-emitting material Q1 may be formed between the first upper metal layer 16 and the first outer metal layer 18.

[0049] Similarly, the second light-emitting element D2 may include a second inner metal layer 20 and a light-transmitting layer 21, and a resonant structure that enhances the peak wavelength of light emitted by the second light-emitting material Q2 may be formed between the second inner metal layer 20 and the second lower metal layer 22. And / or, the second light-emitting element D2 may also include a second outer metal layer 28 and a light-transmitting layer 27, and a resonant structure that enhances the peak wavelength of light emitted by the second light-emitting material Q2 may be formed between the second upper metal layer 26 and the second outer metal layer 28.

[0050] The third light-emitting element D3 may also include a third inner metal layer 30 and a light-transmitting layer 31, and / or may include a third outer metal layer 38 and a light-transmitting layer 37.

[0051] The display device 1 disclosed herein may also include an inner relay metal layer 40 and / or an outer relay metal layer 48 that overlap with the embankment BK when viewed from above. A buffer layer 41 may not exist between the inner relay metal layer 40 and the first relay metal layer 42, or a buffer layer may not exist between the second relay metal layer 46 and the outer relay metal layer 48.

[0052] This third embodiment can be combined with the first and second embodiments described above.

[0053] <Fourth Implementation Method> Figure 6 This is a cross-sectional view showing an example of a schematic configuration of the display area of ​​a display device according to an embodiment of the present disclosure. For example... Figure 6 As shown, the first intermediate layer 14 may contain a photoluminescent material P1. The photoluminescent material P1 is capable of emitting light when excited by light of the emission peak wavelength of the first luminescent material Q1. The photoluminescent material P1 contains, for example, luminescent quantum dots that can emit light through photoexcitation.

[0054] Based on the above configuration, the photoluminescent material P1 can absorb light that cannot propagate from the direction of the first light-emitting element D1 and then re-emit it. Therefore, through the photon recycling effect, the light extraction efficiency of the first light-emitting element D1 can be improved, and the front brightness of the first light-emitting element D1 can be further improved.

[0055] Photoluminescent material P1 can emit light of the same color as the first luminescent material Q1. For example, the difference between the emission peak wavelength of the first luminescent material Q1 and the emission peak wavelength of photoluminescent material P1 can be less than 15 nm. Similarly, photoluminescent material P2 can emit light of the same color as the second luminescent material Q2. Thus, the color purity of the first luminescent element D1 can be further improved.

[0056] Similarly, the second intermediate layer 24 may contain a photoluminescent material P2. The photoluminescent material P2 can be excited by light of the emission peak wavelength of the second luminescent material Q2 to emit light. The photoluminescent material P2 can emit light of the same color as the second luminescent material Q2. Likewise, the third intermediate layer 34 may also contain a photoluminescent material P3.

[0057] This fourth embodiment can be combined with the first to third embodiments described above.

[0058] This disclosure is not limited to the embodiments described above, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical solutions disclosed in different embodiments are also included in the technical scope of this disclosure. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0059] Explanation of reference numerals in the attached figures 1: Display device; 10: First inner metal layer; 11: Translucent layer; 12: First lower metal layer; 14: First intermediate layer; 16: First upper metal layer; 15: Translucent layer; 18: First outer metal layer; 22: Second lower metal layer; 24: Second intermediate layer; 26: Second upper metal layer; 42: First relay metal layer; 44: Buffer layer; 46: Second relay metal layer; D1: First light-emitting element; D2: Second light-emitting element; BK: Embankment; E1: First electrode; E2: Second electrode; L1: First light-emitting layer; L2: Second light-emitting layer; P1, P2: Photoluminescent materials; Q1: The first luminescent material; Q2: Second luminescent material; S1: First light extraction surface; S2: Second light extraction surface; Z1, Z2: Thickness.

Claims

1. A display device, characterized in that, It has a first light-emitting element, the first light-emitting element comprising: First electrode; A first light-emitting element, located above the first electrode, includes a first light-emitting material; and The first light extraction surface is located above the first light-emitting layer. The first light-emitting element includes: A semi-transparent lower metal layer and a semi-transparent upper metal layer are located between the first light-emitting layer and the first light-extracting surface; and The first intermediate layer is located between the first lower metal layer and the first upper metal layer. A resonant structure is formed between the first lower metal layer and the first upper metal layer. The resonant structure enhances the light that has the emission peak wavelength of the first luminescent material and travels in a frontal direction orthogonal to the first light extraction surface.

2. The display device according to claim 1, characterized in that, The first intermediate layer is transparent. The upper surface of the first lower metal layer and the lower surface of the first upper metal layer function as light-reflecting surfaces.

3. The display device according to claim 1 or 2, characterized in that, Let D [nm] be the distance between the first lower metal layer and the first upper metal layer, and let λ [nm] be the peak wavelength of the emitted light. D≤λ×0.2+10[nm], and D≥λ×0.2-10[nm].

4. The display device according to any one of claims 1 to 3, characterized in that, The full width at half maximum (FWHM) of the emission spectrum of the first luminescent material is less than one-tenth of the wavelength of the emission peak.

5. The display device according to any one of claims 1 to 4, characterized in that, The first electrode is light reflective. A resonant structure is formed between the first electrode and the first lower metal layer to enhance light that has the emission peak wavelength and travels in the forward direction.

6. The display device according to any one of claims 1 to 5, characterized in that, The first electrode functions as the anode. At least one of the first lower metal layer and the first upper metal layer functions as a cathode.

7. The display device according to any one of claims 1 to 6, characterized in that, The brightness of the direction forming an angle of 40° or more relative to the front direction is less than 50% of the brightness of the front direction.

8. The display device according to any one of claims 1 to 7, characterized in that, The first luminescent material contains quantum dots.

9. The display device according to any one of claims 1 to 8, characterized in that, The first intermediate layer is conductive.

10. The display device according to claim 9, characterized in that, The first lower metal layer and the first upper metal layer are electrically connected via the first intermediate layer.

11. The display device according to any one of claims 1 to 8, characterized in that, The first intermediate layer is insulating.

12. The display device according to any one of claims 1 to 11, characterized in that, A semi-transparent first inner metal layer is included between the first light-emitting layer and the first lower metal layer.

13. The display device according to claim 12, characterized in that, A light-transmitting layer made of the same material as the first intermediate layer is disposed between the first inner metal layer and the first lower metal layer.

14. The display device according to any one of claims 1 to 13, characterized in that, The first lower metal layer contains aluminum.

15. The display device according to any one of claims 1 to 14, characterized in that, The thickness of the first lower metal layer is less than 10 nm.

16. The display device according to any one of claims 1 to 15, characterized in that, The first intermediate layer contains a photoluminescent material.

17. The display device according to claim 16, characterized in that, The photoluminescent material is excited by light of the emission peak wavelength.

18. The display device according to claim 16 or 17, characterized in that, The photoluminescent material contains quantum dots.

19. The display device according to any one of claims 16 to 18, characterized in that, The difference between the peak emission wavelength of the first luminescent material and the peak emission wavelength of the photoluminescent material is less than 15 nm.

20. The display device according to any one of claims 1 to 19, characterized in that, The display device includes a second light-emitting element, the second light-emitting element having: Second electrode; The second light-emitting layer is located above the second electrode and includes the second light-emitting material; as well as The second light extraction surface is located above the second light-emitting layer. The second light-emitting element includes: A semi-transparent second lower metal layer and a semi-transparent second upper metal layer are located between the second light-emitting layer and the second light-extracting surface; as well as The second intermediate layer is located between the second lower metal layer and the second upper metal layer. A resonant structure is formed between the second lower metal layer and the second upper metal layer, the resonant structure enhancing the light having the emission peak wavelength of the second luminescent material and traveling in the forward direction.

21. The display device according to claim 20, characterized in that, The first light-emitting element and the second light-emitting element are adjacent to each other across a dam; The first light-emitting element and the second light-emitting layer emit light of different colors.

22. The display device according to claim 21, characterized in that, The display device includes a first relay metal layer and a second relay metal layer, which overlap with the embankment when viewed from above. The first lower metal layer and the second lower metal layer are connected via the first relay metal layer. The second upper metal layer and the second upper metal layer are connected via the second relay metal layer.

23. The display device according to claim 22, characterized in that, The peak emission wavelength of the first luminescent material is greater than that of the second luminescent material. The distance between the first lower metal layer and the first upper metal layer is greater than the distance between the second lower metal layer and the second upper metal layer.

24. The display device according to claim 22 or 23, characterized in that, A buffer layer is disposed between the first relay metal layer and the second relay metal layer. The thickness of the buffer layer above the upper surface of the embankment is such that the magnitude of the light is reduced as follows: light having the emission peak wavelength of the first luminescent material and traveling in the frontal direction and light having the emission peak wavelength of the second luminescent material and traveling in the frontal direction.

25. The display device according to claim 24, characterized in that, The buffer layer is made of the same material as the first intermediate layer and the second intermediate layer.

26. The display device according to claim 24 or 25, characterized in that, The thickness of the buffer layer on the cross section parallel to the normal of the first electrode and passing through the slope of the dam is greater than the thickness of the first intermediate layer on the cross section parallel to the normal of the first electrode and passing through the central portion of the first electrode.

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