Light-emitting element, display device, and method for manufacturing light-emitting element

Abstract

A first functional layer (F1) of a light-emitting element (ES) of the present disclosure includes a first portion (P1) and a second portion (P2) that is positioned further outward than the first portion (P1) of the first functional layer (F1) and is thicker than the first portion (P1).

Description

Technical Field

[0001] The present disclosure relates to a light-emitting element, a display device, and a method for manufacturing the light-emitting element. Background Art

[0002] Patent Document 1 discloses a light-emitting element in which a reflective layer is provided on a side surface of a partition wall. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-9793 (published on January 14, 2010) Summary of the Invention Technical problems to be solved by the present disclosure

[0004] However, when the reflective layer is also widely provided on the side surfaces of the partition walls as in Patent Document 1, the possibility of unintended scattering and / or reflection of light increases, which may cause a problem in that the quality of the light-emitting element may be degraded. Technical solutions to technical problems

[0005] A light-emitting element according to a technical solution of the present disclosure includes: a bank; a first light-reflecting layer located above the bank; and a first functional layer located above the first light-reflecting layer, wherein the first functional layer includes: a first portion; and a second portion located further outward than the first portion of the first functional layer and thicker than the first portion.

[0006] According to one aspect of the present disclosure, a method for manufacturing a light-emitting element includes: forming a bank; forming a light-reflecting layer above the bank; and forming a functional layer above the light-reflecting layer, wherein the functional layer is formed in the step of forming the functional layer, the functional layer including a first portion and a second portion, the second portion being located outside the first portion of the functional layer and being thicker than the first portion. Beneficial effects

[0007] According to the present disclosure, a high-quality light-emitting element can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a conceptual diagram showing a configuration example of a display device according to one embodiment of the present disclosure. Figure 2 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 3 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 4This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 5 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 6 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 7 It shows Figure 2 FIG. 1 is a flow chart showing an example of a method for manufacturing a light-emitting element. Figure 8 It shows Figure 2 A cross-sectional view showing an example of a method for manufacturing a light-emitting element. Figure 9 It is a cross-sectional view showing another example of the process of forming a reflective film. Figure 10 It is a cross-sectional view showing another example of the process of forming a reflective film. Figure 11 This is a cross-sectional view showing an example of a process of forming the first functional layer. Figure 12 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 13 It shows Figure 12 FIG. 1 is a flow chart showing an example of a method for manufacturing a light-emitting element. Figure 14 Yes Figure 12 A cross-sectional view showing an example of a method for manufacturing a light-emitting element. Figure 15 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 16 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 17 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 18 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 19 This is a cross-sectional view illustrating an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 20 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 21 for Figure 20 AA cross-section diagram. Figure 22 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 23 for Figure 22 BB cross-section diagram. Figure 24 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 25 is a cross-sectional view showing a light emitting element of the present disclosure. DETAILED DESCRIPTION

[0009] [First embodiment] (Display device) Figure 1 : is a conceptual diagram showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 1 As shown, the display device 1 includes a display area DA and a frame area NA surrounding the display area DA.

[0010] In the display area DA, a light emitting element ES (refer to Figure 2 ), a red sub-pixel Pr including a light-emitting element ES that emits green light, and a blue sub-pixel Pb including a light-emitting element ES that emits blue light. Hereinafter, the red sub-pixel Pr, the green sub-pixel Pg, and the blue sub-pixel Pb are collectively referred to as "sub-pixels P." Figure 1 The example of the sub-pixels P being arranged in an oblique manner is shown, but the arrangement is not limited thereto. The sub-pixels P may also be arranged in any other arrangement, such as a stripe arrangement or a pen-tile arrangement. Each sub-pixel P includes one or more light-emitting elements ES of the present disclosure and a pixel circuit for controlling the one or more light-emitting elements ES.

[0011] The frame area NA includes a gate driver GD, a source driver SD, wiring (not shown) connecting the display area DA with the gate driver GD and the source driver SD, and wiring and terminals (not shown) for supplying power and signals to the gate driver GD and the source driver SD.

[0012] (Cross-sectional structure of display area) Figure 2 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 2 As shown, the display device 1 of the present disclosure includes: a support substrate 2; a circuit layer 3 formed on the support substrate 2 and including pixel circuits; a planarization film 4 formed on the circuit layer 3; and a light-emitting element layer 5 formed on the planarization film 4 and including light-emitting elements ES. The display device 1 may include multiple light-emitting elements ES.

[0013] The light-emitting element ES disclosed herein includes a bank BK, a first light-reflecting layer R1 located above the bank BK, and a first functional layer F1 located above the first light-reflecting layer R1. The first functional layer F1 includes a first portion P1, PA located above the bank BK, and a second portion P2 located above the bank BK, outward from the first portion of the first functional layer F1, and thicker than the first portion P1, PA. The second portion P2 may protrude upward relative to the first portion P1, PA.

[0014] The first portion P1 and PA may also include a first portion P1 located above the first light-reflecting layer R1 and a first portion PA located outside the first light-reflecting layer R1 in the first functional layer F1. The second portion P2 is thicker than one or both of the first portion P1 and PA. In this disclosure, "outside a layer" refers to the side closer to the periphery of that layer. Therefore, the second portion P2 is closer to the periphery of the first functional layer F1 than the first portion P1 and PA. Furthermore, the first portion PA is closer to the periphery of the first functional layer F1 than the first portion PA.

[0015] Figure 25 FIG. 1 is a cross-sectional view showing a light emitting element of the present disclosure. Figure 25 The light emitting element X shown includes a functional layer F11 and a light reflecting layer R11. The functional layer F11 includes a first portion P11 located above the light reflecting layer R11 and a second portion P12 located above the light reflecting layer R11 and thicker than the first portion P1. The first portion P1 is formed, for example, to protrude upward in a convex shape. The first portion and the second portion may or may not be located above the bank. Figure 25 Even when forming a light-reflecting layer R11 above the bank BK, the ends of the functional layer F11 can be made thicker, allowing the waveguide light within the functional layer F11 to be more easily concentrated at the ends. This prevents unintended scattering and reflection, further stabilizing the quality of the light-emitting element. Specifically, while the quality of the light-emitting element can be improved, for example, by suppressing variations in viewing angle characteristics caused by variations in the light distribution within the pixel, the quality of such a light-emitting element can be further stabilized.

[0016] exist Figure 2 In the structure shown, the second portion P2 and the first light reflecting layer R1 do not overlap when viewed from above. Therefore, the first light reflecting layer R1 is less likely to reflect the light scattered by the second portion P2. Figure 25Compared with the light reflected by the light reflecting layer R11, the second portion P2 is more regular. Therefore, the influence of light scattering caused by the second portion P2 can be reduced, and the first functional layer F1 and the first light reflecting layer R1 can function more effectively. Moreover, the second portion P2 is located in the depression formed between the upper surface of the bank BK and the end face of the first light reflecting layer R1. Therefore, it is easier to suppress the scattering of light concentrated at the end of the functional layer F11, which can make the quality of the light emitting element more stable. Therefore, according to Figure 2 The structure shown can achieve a light-emitting element ES with even lower quality. Furthermore, by making the quality of the light-emitting element more stable, it is possible to suppress degradation in the display quality of a display device equipped with the light-emitting element. Furthermore, while the display quality of a display device may suffer from issues such as optical crosstalk, controlling optical crosstalk is easier, minimizing degradation in display quality. Furthermore, by forming the end of the functional layer F11 into a recessed shape, it is possible to suppress peeling of the functional layer F11 from the end, thereby preventing defects in the display.

[0017] The bank BK is an insulator and can be formed of a resin or a photosensitive resin. The first light-reflecting layer R1 can include a film that reflects light, for example, a thin film of silver (Ag), an AgMg alloy containing silver and magnesium (Mg), or aluminum (Al). The first light-reflecting layer R1 can be composed of multiple layers, for example, it can have a first film M1 that reflects light and a second film M2 that is located above the first film M1 and transmits light. The first functional layer F1 is an arbitrary functional layer, for example, it can be any one of a hole injection layer, a hole transport layer, an electron shielding layer, a light-emitting layer, a hole shielding layer, an electron transport layer, and an electron injection layer. The light-emitting element ES may also appropriately include functional layers other than the first functional layer F1.

[0018] The hole injection layer and hole transport layer contain a hole transport material and / or a photosensitive hole transport material. Examples of hole transport materials include NiO, Cu, Cu2O, CoO, Cr2O3, and CuAlS2. Examples of photosensitive hole transport materials include OTPD, QUPD, and X-F6-TAPC. The electron transport layer and electron injection layer contain ZnO, ZnS, ZrO, MgZnO, AlZnO, and TiO2.

[0019] The light-emitting layer comprises an inorganic or organic light-emitting material, such as quantum dots, which emit light through the recombination of electrons and holes. Quantum dots can be core-type, core-shell type, or core-multishell type. Examples of the core / shell materials in core-shell quantum dots include: CdSe / CdS, CdSe / ZnS, CdTe / CdS, InP / ZnS, GaP / ZnS, Si / ZnS, InN / GaN, InP / CdSSe, InP / ZnSeTe, GaInP / ZnSe, GaInP / ZnS, Si / AlP, InP / ZnSTe, GaInP / ZnSTe, GaInP / ZnSSe, etc.

[0020] In addition, the light-emitting layer may also be composed of a plurality of quantum dots and a matrix that holds the quantum dots. The so-called holding quantum dots means that at least a portion of the region sandwiched by two adjacent quantum dots is buried by the matrix. The matrix may be formed, for example, as a continuous film. A continuous film refers to a film that is not interrupted by materials other than the material constituting the continuous film. The continuous film may also be an integrated film that is continuously connected by chemical bonds of the materials contained in the matrix. In addition, the continuous film may also be formed, for example, to have a 1000 nm thickness in the surface direction perpendicular to the film thickness direction. 2 The matrix may be, for example, an inorganic matrix mainly composed of an inorganic compound. The inorganic compound may be, for example, a metal sulfide such as ZnS.

[0021] The second portion P2 may not overlap with the first light reflecting layer R1 in a plan view, or may be the outer periphery of the first functional layer F1. The second portion P2 may have an end surface EF that does not overlap with the first light reflecting layer R1 in a plan view.

[0022] A first opening A1 is formed in the bank BK, and the light-emitting element ES includes an electrode E1 that overlaps with the first opening A1 when viewed from above. The electrode E1 may be an island-shaped electrode provided in a sub-pixel P. The light-emitting element ES may include a counter electrode CE opposing the electrode E1, and the first functional layer F1 may be located between the electrode E1 and the counter electrode CE. The counter electrode CE may also be composed of silver nanowires (AgNWs), a silver thin film, or a transparent conductive film. The counter electrode CE may also be a common electrode provided across multiple sub-pixels P. The first light-reflecting layer R1 covers part or all of the sidewalls of the first opening A1. The first light-reflecting layer R1 may also cover a portion of the upper surface of the bank BK.

[0023] The electrode E1 can be a reflective electrode that reflects light, and can, for example, include a thin film of silver, an AgMg alloy, or aluminum. The electrode E1 can be composed of multiple layers, for example, having a first film M1 that reflects light and a second film M2 that is located above the first film M1 and transmits light. The electrode E1 can be designed to fit into the optical cavity of the light-emitting element ES. In this disclosure, for simplicity, an example is described in which the electrode E1 is an anode and the counter electrode CE is a cathode. This is not limiting, and examples in which the electrode E1 is a cathode and the counter electrode CE is an anode are also within the scope of this disclosure.

[0024] The electrode E1 may be in contact with the first light-reflecting layer R1 or may be electrically connected to the first light-reflecting layer R1. The electrode E1 may share one or more layers with the first light-reflecting layer R1, or the entire electrode E1 may be formed from the same layer as the first light-reflecting layer R1. Forming the electrode E1 from the same layer as the first light-reflecting layer R1 offers the advantage of being able to form the electrode E1 and the first light-reflecting layer R1 in the same process. The electrode E1 may be integral with the first light-reflecting layer R1, and the light-emitting element ES may include a single reflective film B1 including the electrode E1 and the first light-reflecting layer R1.

[0025] In this disclosure, "the same layer" means formed by the same process (film formation step) and is formed from substantially the same material. Substantially the same material includes materials obtained by subjecting the same material to treatments such as doping or light irradiation. A "lower layer" means formed in a process prior to the comparison layer, and an "upper layer" means formed in a process subsequent to the comparison layer. "Other layers" include both lower and upper layers.

[0026] The light-emitting element ES may further include an insulating layer D1 positioned between the first light-reflecting layer R1 and the first functional layer F1. The insulating layer D1 may also be an inorganic insulating layer comprising an inorganic insulator such as silicon oxide or silicon nitride. The insulating layer D1 may cover the first light-reflecting layer R1, thereby insulating the first light-reflecting layer R1 from the first functional layer F1. The light-emitting element ES may further include a sealing layer TEF covering the counter electrode CE.

[0027] The light-emitting element ES may further include a first light-refractive layer 12, which is located above the first functional layer F1. The first light-refractive layer 12 may be located above the counter electrode CE or may be included in the sealing layer TEF. For example, the first light-refractive layer 12 may be an organic resin film, and the sealing layer TEF may include the first light-refractive layer 12 and an inorganic film 13 located above the first light-refractive layer 12.

[0028] The refractive index of the first refractive layer 12 can be greater than that of the external environment (typically, the atmosphere). In this case, light intended to be emitted obliquely from the first refractive layer 12 toward the external environment is reflected at the boundary surface and easily returns to the interior of the light-emitting element ES. A portion of the returned light is multiply semi-reflected within the light-emitting element ES and is emitted from the first refractive layer 12 toward the external environment in a forward direction. A structure suitable for improving the frontal brightness of the light-emitting element ES can be determined based on optical calculations.

[0029] The first optical refractive layer 12 may be thinner above the upper surface of the bank BK. Preferably, the first optical refractive layer 12 is formed so that, when viewed from above, the first optical refractive layer 12 and at least a portion of the upper surface of the bank BK do not overlap. By interrupting the first optical refractive layer 12 above the bank BK, optical crosstalk caused by the first optical refractive layer 12 can be reduced.

[0030] The display device 1 further includes a second light-reflecting layer R2 positioned above the bank BK. A second opening A2 is formed by the first and second light-reflecting layers R1 and R2. When viewed from above, the second portion P2 of the first functional layer F1 and the second opening A2 may overlap. The second opening A2 is a recess formed between the first and second light-reflecting layers R1 and R2. In other words, when viewed from above, the second portion P2 may be located between the first and second light-reflecting layers R1 and R2.

[0031] The second light-reflecting layer R2 may include a light-reflecting film or may be composed of multiple layers. The outer shape of the second light-reflecting layer R2 may be similar or different from that of the first light-reflecting layer R1. The second light-reflecting layer R2 may be electrically isolated from the first light-reflecting layer R1. The second light-reflecting layer R2 may be formed from the same layer as the first light-reflecting layer or from a different layer. The first light-reflecting layer R1 and the second light-reflecting layer R2 may each be formed from a pixel unit. The insulating layer D1 can insulate the first light-reflecting layer R1 from the second light-reflecting layer R2.

[0032] (Planar structure 1 of display area) Figure 3 and Figure 4 Each of them is a plan view showing an example of the configuration of a display device according to an embodiment of the present disclosure. Figure 3 As shown in FIG, when viewed from above, the shape of the first light reflecting layer R1 and the shape of the first functional layer F1 may be similar. Figure 4As shown, in a top view, the outer shape of the first light reflecting layer R1 and the outer shape of the first functional layer F1 may not be similar. For example, the first light reflecting layer R1 may include an angular shape, and the first functional layer F1 may include a circular shape. For example, the first light reflecting layer R1 may also include a corrugated shape, and the first functional layer F1 may not include a corrugated shape. The corrugated shape has the advantage of improving adhesion by dispersing stress. Therefore, the first light reflecting layer R1 with a corrugated shape has good adhesion to the lower layer and is difficult to peel off when forming a layer higher than the first light reflecting layer R1. Figure 3 and Figure 4 As shown, in a plan view, the first light reflecting layer R1 may be in a shape surrounding a portion of the first functional layer F1.

[0033] (Planar structure 2 of display area) Figure 5 and Figure 6 Each of them is a plan view showing an example of the configuration of a display device according to an embodiment of the present disclosure. Figure 5 as well as Figure 6 As shown in FIG. 1 , when viewed from above, the first light reflecting layer R1 may also be in a shape that does not surround the first functional layer F1. Figure 6 As shown, the first light reflecting layer R1 may also include a corrugated shape when viewed from above.

[0034] (Method for Manufacturing Light-Emitting Element) Figure 7 Yes Figure 2 FIG. 1 is a flow chart showing an example of a method for manufacturing a light-emitting element. Figure 8 Yes Figure 2 A cross-sectional view showing an example of a method for manufacturing a light-emitting element. Figure 9 and Figure 10 Each of them is a cross-sectional view showing another example of the process of forming a reflective film. Figure 11 This is a cross-sectional view showing an example of the process of forming the first functional layer.

[0035] like Figure 7 and Figure 8 As shown, banks BK are formed on the planarizing film 4 (step S20), and a reflective film B1 including an electrode E1 and a first light-reflecting layer R1 is formed on top of the banks BK (step S40). Next, an insulating layer D1 is formed on top of the first light-reflecting layer R1 (step S50), and a first functional layer F1 is formed on top of the first light-reflecting layer R1 (step S60). Then, a counter electrode CE is formed (step S70), and a sealing layer TEF is formed (step S80). Furthermore, functional layers other than the first functional layer F1 are formed as appropriate between steps S50 and S70.

[0036] In the process of forming the reflective film B1 (step S40), the reflective film B1 can be formed by evaporation or sputtering. When the reflective film B1 is composed of multiple layers, each layer can be formed in sequence by evaporation or sputtering. Figure 8 As shown, a mask W1 is used to pattern the reflective film B1. Alternatively, as shown Figure 9 As shown, the reflective film B1 can be patterned by etching. Specifically, a photoresist W3 can be formed and patterned on the reflective film B1 as a template, and the reflective film B1 can be etched with an acidic solution to pattern the reflective film B1. After etching, a solvent is used to remove the photoresist W3. Alternatively, as shown in FIG. Figure 10 As shown, the reflective film B1 can be patterned by a lift-off method. Specifically, a photoresist W4 can be formed and patterned in advance as a template, and the reflective film B1 can be formed on the photoresist W4 and in the non-formed portion of the photoresist W4. The reflective film B1 is patterned by removing the photoresist W4.

[0037] In the step of forming the insulating layer D1 (step S50), the insulating layer D1 can be formed by evaporation or sputtering. Figure 8 As shown, the insulating layer D1 may be patterned using a mask W2. Alternatively, the insulating layer D1 may be patterned by etching or stripping.

[0038] In the process of forming the first functional layer F1 (step S60), the first functional layer F1 is formed, which has: a first part P1, PA located above the embankment BK; and a second part P2, which is located above the embankment BK and is further outward than the first part P1, PA in the first functional layer F1, and is thicker than the first part P1, PA.

[0039] like Figure 11 As shown, in the step of forming the first functional layer F1 (step S60), the first functional layer F1 can be patterned using a lift-off method. Specifically, a photoresist W5 having a first end surface G1 is formed above the bank BK and in the portion where the first light-reflecting layer R1 is not formed. A third film M3 containing the material of the first functional layer F1 is formed on the photoresist W5 and in the portion where the photoresist W5 is not formed. After forming the third film M3, the photoresist W5 is removed, so that the end surface EF of the second portion P2, i.e., the second end surface G2, can be formed at a position that does not overlap with the first light-reflecting layer R1 when viewed from above.

[0040] Alternatively, the first functional layer F1 can be formed using inkjet technology. The end of the first functional layer F1 can be thickened due to surface tension. An example of such an end is a structure produced by the so-called coffee ring phenomenon.

[0041] [Second embodiment] For the sake of convenience, components having the same functions as those described in the above embodiments are denoted by the same reference numerals, and their description will not be repeated.

[0042] Figure 12 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 12 As shown, the electrode E1 may not be in contact with the first light-reflecting layer R1, or it may be electrically separated from the first light-reflecting layer R1. The electrode E1 may be formed from a layer different from the first light-reflecting layer R1. Since the first light-reflecting layer R1 is separated from the electrode E1, current leakage between adjacent light-emitting elements ES, also known as "lateral current leakage," can be reduced.

[0043] The light-emitting element ES may further include an insulating layer D2 positioned between the first light-reflecting layer R1 and the electrode E1. The insulating layer D2 may be an inorganic insulating layer composed of an inorganic insulator such as silicon oxide or silicon nitride. The insulating layer D2 insulates the first light-reflecting layer R1 from the electrode E1. The light-emitting element ES may further include an inorganic film 11 positioned between the counter electrode CE and the first light-refractive layer 12. The inorganic film 11 protects the counter electrode CE during formation of the first light-refractive layer 12.

[0044] Figure 13 It shows Figure 12 FIG. 1 is a flow chart showing an example of a method for manufacturing a light-emitting element. Figure 14 It shows Figure 12 A cross-sectional view of an example of a method for manufacturing a light-emitting element is shown. Figure 13 and Figure 14 As shown, an electrode E1 is formed on the planarizing film 4 (step S110), and banks BK are formed on the planarizing film 4 (step S120). Next, an insulating layer D2 is formed on the banks BK (step S130), and a first light reflecting layer R1 is formed on the banks BK (step S140). Then, steps S50, S60, S70, and S80 are performed.

[0045] [Third embodiment] Figure 15 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 15As shown, the light-emitting element ES can include a second functional layer F2, which includes a third portion P3 and PB located above the first portion P1 and PA, and a fourth portion P4 located above the second portion P2. The second functional layer F2 can be, for example, a hole injection layer, a hole transport layer, an electron shielding layer, a light-emitting layer, a hole shielding layer, an electron transport layer, or an electron injection layer. When the first functional layer F1 is a light-emitting layer, the second functional layer F2 can be a light-emitting layer of the same color as the first functional layer F1, or a light-emitting layer of a different color.

[0046] The second functional layer F2 can be located directly above the first functional layer F1 and can be in contact with the first functional layer F1. The second functional layer F2 can be patterned in the same process as the first functional layer F1, or can be patterned into the same shape as the first functional layer F1. The fourth portion P4 can have an end surface that overlaps with the end surface EF of the second portion P2 when viewed from above. One or more functional layers other than the second functional layer F2 can be patterned into the same shape using the same process as the first functional layer F1, and the end surfaces of each functional layer can overlap with the end surface EF of the first functional layer F1 when viewed from above.

[0047] According to the configuration of this embodiment, the number of steps can be reduced by patterning the first functional layer F1 and the second functional layer F2 in the same process. The second portion P2 and the fourth portion P4 are located in the recess formed between the upper surface of the bank BK and the end face of the first light-reflecting layer R1. Therefore, the fourth portion P4 is less likely to peel off, and formation defects are less likely to occur in the upper layer of the second functional layer F2.

[0048] [Fourth embodiment] Figure 16 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 16 As shown, the light emitting element ES includes a first light refractive layer 12 and a second light refractive layer 14 located above the first light refractive layer 12. The refractive index of the second light refractive layer 14 may be lower than that of the first light refractive layer. The second light refractive layer 14 may be in direct contact with the first light refractive layer 12. The difference in refractive index between the first light refractive layer 12 and the second light refractive layer 14 increases the reflectivity of light incident from the first light refractive layer 12 to the second light refractive layer 14.

[0049] [Fifth embodiment] Figure 17 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 17As shown, a recess 15 is formed on the upper surface of the bank BK. When viewed from above, the second portion P2 and the recess 15 can overlap. Consequently, even if the first light-reflecting layer R1 is thin, the second portion P2 is less likely to peel off, and defects are less likely to occur in the upper layer of the first functional layer F1. Consequently, the cost of the first light-reflecting layer R1 can be reduced, and the film thickness of the first light-reflecting layer R1 can be adjusted with greater flexibility.

[0050] The light-emitting element ES of this embodiment includes: a bank BK with a recess 15 formed on the upper surface; a first light-reflecting layer R1 located above the bank BK; and a first functional layer F1 located above the first light-reflecting layer R1. The first functional layer F1 includes: a first portion P1 and PA located above the bank BK; and a second portion P2 located above the bank BK and on the outside of the first portion of the first functional layer F1, which is thicker than the first portion P1 and PA. When viewed from above, the second portion P2 and the recess 15 overlap with each other.

[0051] The manufacturing method of the light-emitting element ES of this embodiment includes: a step of forming a bank BK having a recess 15 formed on the upper surface; a step of forming a first light-reflecting layer R1 in a layer above the bank BK; and a step of forming a first functional layer F1 in a layer above the first light-reflecting layer R1. In the step of forming the first functional layer F1, the first functional layer F1 is formed so that the second portion P2 and the recess 15 overlap with each other when viewed from above. The first functional layer F1 includes a first portion P1 and PA located above the bank BK, and a second portion P2. The second portion P2 is located above the bank BK and on the outside of the first portions P1 and PA in the first functional layer F1, and is thicker than the first portions P1 and PA. [Sixth embodiment] Figure 18 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 18 As shown, the display device 1 may include a second light-reflecting layer R2 located above the bank BK, a third light-reflecting layer R3 located above the bank BK, and a third functional layer F3 located above the second light-reflecting layer R2. The third functional layer F3 includes a fifth portion P5, PC located above the bank BK, and a sixth portion P6 located above the bank BK, outward from the fifth portion of the third functional layer F3, and thicker than the fifth portion P5, PC. The fifth portion P5, PC may include the fifth portion P5 located above the second light-reflecting layer R2 and the fifth portion PC located outward from the second light-reflecting layer R2 of the second functional layer F2. The sixth portion P6 is thicker than one or both of the fifth portion P5 and the fifth portion P5.

[0052] The first light reflecting layer R1 and the third light reflecting layer R3 form a third opening A3, and the third light reflecting layer R3 and the second light reflecting layer R2 form a fourth opening A4. When viewed from above, the second portion P2 overlaps with the third opening A3, and the sixth portion P6 overlaps with the fourth opening A4.

[0053] According to the configuration of this embodiment, the end of a functional layer is located within a single opening. Therefore, unlike when the ends of two or more functional layers are located within a single opening, overlapping of the ends of the two or more functional layers is not a concern. Therefore, this configuration can reduce the depth of the third opening A3 and the fourth opening A4, improving the flatness of the lower layer relative to the first and third functional layers F1 and F3. This improves coating properties when forming the first and third functional layers F1 and F3, as well as when forming the upper layers of the first and third functional layers F1 and F3, thereby increasing manufacturing efficiency.

[0054] [Seventh embodiment] Figure 19 : is a cross-sectional view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 19 As shown, the display device 1 may include a second light reflecting layer R2 located above the bank BK, a third light reflecting layer R3 located above the bank BK, and a third functional layer F3 located above the second light reflecting layer R2, the third functional layer F3 including: a fifth portion P5, PC located above the second light reflecting layer R2; and a sixth portion P6 located above the bank BK and on the outside of the fifth portion in the third functional layer F3, and thicker than the fifth portion P5, PC.

[0055] The first light reflecting layer R1 and the third light reflecting layer R3 form a third opening A3, and the third light reflecting layer R3 and the second light reflecting layer R2 form a fourth opening A4. When viewed from above, the second portion P2 overlaps with the fourth opening A4, and the sixth portion P6 overlaps with the third opening A3.

[0056] According to the configuration of this embodiment, for the same reasons as the configuration of the fifth embodiment described above, the depths of the third opening A3 and the fourth opening A4 can be reduced. Furthermore, according to the configuration of this embodiment, the areas of the first functional layer F1 and the third functional layer F3 can be made larger than those of the configuration of the fifth embodiment described above. When patterning the functional layer using a lift-off method, the larger the template opening, the easier it is to apply the functional layer material within the opening. Therefore, the depths of the third opening A3 and the fourth opening A4 can be further reduced. As a result, the flatness of the underlying layer can be further improved, the coating properties can be further improved, and the manufacturing efficiency can be further improved.

[0057] [Eighth Embodiment] Figure 20 This is a plan view showing an example of the configuration of a display device according to one embodiment of the present disclosure. Figure 21 yes Figure 20 AA cross-section diagram. Figure 20 as well as Figure 21 As shown, the display device 1 can include multiple light-emitting elements ES for each pixel. By providing multiple light-emitting elements ES for each pixel, the number of light-emitting elements ES can be reduced, increasing the area of the first light-reflecting layer R1 per light-emitting area. The multiple light-emitting elements ES can be of any number, shape, and arrangement.

[0058] Figure 22 This is a plan view showing a modified example of the configuration of the display device according to the embodiment of the present disclosure. Figure 23 for Figure 22 BB cross-section diagram. Figure 22 and Figure 23 As shown, the first functional layers F1 of multiple light-emitting elements ES can be formed integrally with each other on a pixel basis. Furthermore, the electrode E1, insulating layer D1, and other components can also be formed integrally with each pixel. In other words, multiple light-emitting elements ES belonging to the same pixel can share one or more components.

[0059] Figure 24 1 is a top view showing a modified example of the configuration of a display device according to an embodiment of the present disclosure. Figure 24 As shown, the display device 1 includes a light emitting element ES that is elongated relative to one pixel in a plan view, thereby increasing the area of the first light reflecting layer R1 per light emitting area. The light emitting element ES may have a corrugated shape or a spiral shape.

[0060] The present disclosure is not limited to the aforementioned embodiments; various modifications are possible within the scope of the claims. Embodiments resulting from appropriate combinations of the technical solutions disclosed in different embodiments are also encompassed by the technical scope of the present disclosure. Furthermore, new technical features can be created by combining the technical solutions disclosed in the various embodiments. For example, the recess 15 of the fifth embodiment can be provided on the upper surface of the bank BK of the first to fourth, sixth to eighth embodiments, and the second portion P2 and the recess 15 can overlap when viewed from above. Description of Reference Numerals

[0061] 1: Display device 12: First light refraction layer 14: Second light refraction layer 15: concave part A1: First opening A2: Second opening A3: The third opening A4: The fourth opening B1: Reflective film BK: embankment E1: Electrode ES: Light-emitting element EF: End face F1: First functional layer (functional layer) F2: Second functional layer F3: The third functional layer G1: First end face G2: Second end face M1: First membrane M2: Second membrane P1, PA: Part 1 P2: Part 2 P3, PB: Part 3 P4: Part 4 P5, PC: Part 5 P6: Part 6 R1: First light reflecting layer (light reflecting layer) R2: Second light reflecting layer R3: The third light reflecting layer W5: Photoresist

Claims

1. A light-emitting element, characterized in that: It has: embankment fence; a first light reflecting layer located above the bank; and a first functional layer located above the first light reflecting layer; The first functional layer comprises: Part I; The second portion is located outside the first portion of the first functional layer and is thicker than the first portion.

2. The light-emitting element according to claim 1, wherein The first portion and the second portion are located above the embankment.

3. The light-emitting element according to claim 1 or 2, wherein: The second portion protrudes upward relative to the first portion.

4. The light-emitting element according to any one of claims 1 to 3, wherein The second portion has an end surface that does not overlap with the first light reflecting layer in a plan view.

5. The light-emitting element according to any one of claims 1 to 4, wherein The first functional layer includes a light-emitting layer.

6. The light-emitting element according to claim 5, wherein The light-emitting layer includes a plurality of quantum dots and an inorganic matrix, and the inorganic matrix holds the plurality of quantum dots.

7. The light-emitting element according to any one of claims 1 to 6, wherein A recess is formed on the upper surface of the embankment. In a plan view, the second portion and the recess overlap with each other.

8. The light-emitting element according to any one of claims 1 to 7, wherein A first opening is formed on the embankment portion, An electrode is further provided, and the electrode overlaps with the first opening in a plan view.

9. The light-emitting element according to claim 8, wherein The electrode is in contact with the first light reflecting layer.

10. The light-emitting element according to claim 8, wherein The electrode does not contact the first light reflecting layer.

11. The light-emitting element according to claim 8, wherein A reflective film is provided, and the reflective film includes the electrode and the first light reflecting layer.

12. The light-emitting element according to any one of claims 8 to 11, wherein At least one of the first light reflecting layer and the electrode includes a first film that reflects light and a second film that is located above the first film and transmits light.

13. The light-emitting element according to any one of claims 1 to 12, wherein In a plan view, the first light reflecting layer has an outer shape similar to that of the first functional layer.

14. The light-emitting element according to any one of claims 1 to 13, wherein The first light reflecting layer has a shape surrounding a portion of the first functional layer in a plan view.

15. The light-emitting element according to any one of claims 1 to 13, wherein The first light reflecting layer has a shape that does not surround the first functional layer in a plan view.

16. The light-emitting element according to any one of claims 1 to 15, wherein The first light reflecting layer includes a corrugated shape when viewed from above.

17. The light-emitting element according to any one of claims 1 to 16, wherein A second functional layer is provided, wherein the second functional layer has a third portion and a fourth portion, wherein the third portion is located above the first portion, and the fourth portion is located above the second portion.

18. The light-emitting element according to any one of claims 1 to 17, wherein A first light-refractive layer is provided, and the first light-refractive layer is located above the first functional layer.

19. The light-emitting element according to claim 18, wherein A second light-refractive layer is provided, the second light-refractive layer being located above the first light-refractive layer, The refractive index of the second light refraction layer is smaller than the refractive index of the first light refraction layer.

20. The light-emitting element according to claim 18 or 19, characterized in that The first light refractive layer and at least a portion of the upper surface of the bank do not overlap with each other in a plan view.

21. A display device comprising the light-emitting element according to any one of claims 1 to 20.

22. The display device according to claim 21, wherein A second light reflecting layer is provided, the second light reflecting layer being located above the bank, A second opening is formed by the first light reflecting layer and the second light reflecting layer, In a plan view, the second portion and the second opening overlap with each other.

23. The display device according to claim 21, wherein have: a second light reflecting layer located above the bank; a third light reflecting layer located above the bank; and a third functional layer located above the second light reflecting layer; The third functional layer has: a fifth portion located above the embankment; a sixth portion, which is located above the bank and outside the fifth portion of the third functional layer and is thicker than the fifth portion; A third opening is formed by the first light reflecting layer and the third light reflecting layer. A fourth opening is formed by the third light reflecting layer and the second light reflecting layer. In a plan view, the second portion and the third opening overlap with each other, and the sixth portion and the fourth opening overlap with each other.

24. The display device according to claim 21, wherein have: a second light reflecting layer located above the bank; a third light reflecting layer located above the bank; and a third functional layer located above the second light reflecting layer; The third functional layer has: a fifth portion located above the embankment; a sixth portion, which is located above the bank and outside the fifth portion of the third functional layer and is thicker than the fifth portion; A third opening is formed by the first light reflecting layer and the third light reflecting layer. A fourth opening is formed by the third light reflecting layer and the second light reflecting layer. In a plan view, the second portion and the fourth opening overlap with each other, and the sixth portion and the third opening overlap with each other. The first functional layer and the third functional layer overlap with each other between the third opening and the fourth opening. 25 . A display device comprising a plurality of light-emitting elements according to claim 1 .

26. The display device according to claim 25, wherein: The first functional layers of a plurality of light-emitting elements are formed integrally with each other in units of pixels of the display device.

27. A method for manufacturing a light emitting element, characterized in that: The method for manufacturing the light-emitting element comprises: The process of forming a levee; forming a light reflecting layer above the bank; and In the step of forming a functional layer above the light reflecting layer, In the step of forming the functional layer, the functional layer is formed. The functional layer includes a first portion and a second portion. The second portion is located outside the first portion of the functional layer and is thicker than the first portion.

28. The method for manufacturing a light-emitting element according to claim 27, wherein: In the process of forming the functional layer, forming a photoresist having a first end face above the bank and in a portion where the light reflecting layer is not formed, After forming a third film containing the material of the functional layer on the non-formed portion of the photoresist, the photoresist is removed to form the end face of the second portion, ie, the second end face, at a position not overlapping with the light reflecting layer in plan view.

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