WO2025150155A1 - Light-emitting element, light-emitting apparatus, and display apparatus - Google Patents

Abstract

A light-emitting element (1) has an upper electrode (UE) and a lower electrode (LE) that face each other, an electro-luminescence (EL) light-emitting layer (E) that receives carrier injection from the upper electrode (UE) and the lower electrode (LE) and emits EL light (81), and an insulating bank (BK) that is positioned on the side of the EL light-emitting layer (E). At least one of the upper electrode (UE) and the lower electrode (LE) is a light-transmitting electrode. The bank (BK) includes a photo-luminescence (PL) material (MP) that emits PL light (82). The main peak wavelength of the EL light (81) is denoted as λ_{EL_PEAK}, and the main peak wavelength of the PL light (82) is denoted as λ_{PL_PEAK}. The PL material (MP) absorbs light of the wavelength λ_{EL_PEAK}. In the light-emitting element (1), λ_{PL_PEAK} - 30 nm ≤ λ_{EL_PEAK} ≤ λ_{PL_PEAK} + 10 nm.

Description

Light-emitting element, light-emitting device, and display device

The following disclosure relates to a light-emitting element having an electroluminescent (EL) light-emitting layer that emits EL light.

Various technologies have been proposed for devices that use EL. For example, the following Patent Document 1 discloses technology aimed at improving the light extraction efficiency of organic EL display devices.

Japanese Patent Publication No. 2017-37825

The purpose of one aspect of the present disclosure is to improve the performance of a light-emitting element having an EL light-emitting layer by using a configuration different from that of conventional devices.

A light-emitting device according to an embodiment of the present disclosure includes an upper electrode and a lower electrode opposed to each other,
an EL light-emitting layer that emits EL (Electro-Luminescence) light upon receiving carrier injection from the upper electrode and the lower electrode, and an insulating bank located on a side of the EL light-emitting layer, wherein at least one of the upper electrode and the lower electrode is a light-transmitting electrode, the bank contains a PL material that emits PL (Photo-Luminescence) light, and when a main peak wavelength of the EL light is expressed as λ _{EL_PEAK} and a main peak wavelength of the PL light is expressed as λ _{PL_PEAK} , the PL material absorbs light of a wavelength λ _{EL_PEAK} ,
λ _{PL_PEAK} -30nm≦λ _{EL_PEAK} ≦λ _{PL_PEAK} +10nm
It is.

According to one aspect of the present disclosure, a configuration different from conventional configurations can improve the performance of a light-emitting element having an EL light-emitting layer.

1 shows a configuration example of a light-emitting element according to a first embodiment. 1 shows a configuration example of a light emitting element according to a second embodiment. 13 shows a configuration example of a light emitting element according to the third embodiment. 10 is a diagram illustrating the relationship between the angle of PL light and radiance. FIG. 1 shows an example of the configuration of a light-emitting element according to a fourth embodiment. 13 shows a configuration example of a light emitting device according to a fifth embodiment. 13 shows another example of the configuration of the light emitting device according to the fifth embodiment. 13 shows an example of the configuration of a light emitting device according to a sixth embodiment. 13 shows another example of the configuration of the light emitting device according to the sixth embodiment. 13 shows a configuration example of a light emitting device according to a seventh embodiment. 13 shows another configuration example of the light emitting device according to the seventh embodiment. 13 shows an example of the configuration of a light emitting device according to an eighth embodiment. 13 shows another example of the configuration of the light emitting device according to the eighth embodiment. 13 shows a configuration example of a light emitting device according to a ninth embodiment. 13 shows another example of the configuration of the light emitting device according to the ninth embodiment. 1 shows a configuration example of a display device according to a tenth embodiment.

[Embodiment 1]
The first embodiment will be described below. For convenience of explanation, components having the same functions as those described in the first embodiment will be given the same reference numerals in the following embodiments, and the explanations will not be repeated. For simplicity, the explanations of known technical matters will be omitted as appropriate. Each component, material, and numerical value described in this specification is merely an example unless otherwise stated. Therefore, for example, unless otherwise stated, the positional relationship of each component is not limited to the example in each figure. In addition, each figure is not necessarily illustrated to scale.

FIG. 1 shows an example of the configuration of a light-emitting element 1 in embodiment 1. FIG. 1 shows a schematic representation of the layered structure of the light-emitting element 1. FIG. 1 shows one light-emitting element 1. For ease of explanation, the present specification introduces an orthogonal coordinate system (XYZ coordinate system) shown in FIG. 1. The Z direction in FIG. 1 is the thickness direction of each part of the light-emitting element 1. The Z direction in FIG. 1 is defined as the normal direction of the horizontal plane of the substrate SB of the light-emitting element 1.

In this specification, the positive direction of the Z direction will be described as the upward direction. Therefore, the negative direction of the Z direction is the downward direction. In the example of Figure 1, the downward direction is defined as the direction toward the substrate SB of the light-emitting element 1. The X direction and Y direction in Figure 1 are each examples of directions that intersect with the Z direction. Of the two directions that intersect with the Z direction, this specification will mainly focus on the X direction.

The light-emitting element 1 has an upper electrode UE and a lower electrode LE that face each other. The upper electrode UE may be either an anode or a cathode, and the lower electrode LE may be the other of an anode or a cathode. In embodiment 1, a case is illustrated in which the lower electrode LE is an anode and the upper electrode UE is a cathode.

The light-emitting element 1 is configured so that the EL light 81 and PL light 82 shown in FIG. 1 can be extracted to the outside of the light-emitting element 1. Therefore, in the light-emitting element 1, at least one of the upper electrode UE and the lower electrode LE may be a light-transmitting electrode. One of the upper electrode UE or the lower electrode LE may be a light-reflecting electrode.

The light-emitting element 1 has a substrate SB that supports each part of the light-emitting element 1. In the example of FIG. 1, the substrate SB is located below the lower electrode LE. As shown in FIG. 1, the distance between the substrate SB and the lower electrode LE is smaller than the distance between the substrate SB and the upper electrode UE.

The light-emitting element 1 includes an EL light-emitting layer E that emits EL light 81 upon receiving carrier injection from the upper electrode UE and the lower electrode LE. The EL light-emitting layer E may be located between the upper electrode UE and the lower electrode LE. In the example of the first embodiment, the lower electrode LE as an anode supplies holes to the EL light-emitting layer E, and the upper electrode UE as a cathode supplies electrons to the EL light-emitting layer E.

The EL layer E may contain any EL material that emits EL light 81 upon recombination of holes supplied from the anode and electrons transported from the cathode. Thus, EL light 81 can be generated in the EL layer E by applying a voltage between the lower electrode LE and the upper electrode UE. In this specification, the main peak wavelength of the EL light (e.g., the EL light 81) is represented as λ _{EL_PEAK} . The main peak wavelength of the EL light is also referred to as the EL main peak wavelength.

The light-emitting element 1 has an insulating bank BK located to the side of the EL light-emitting layer E. In the first embodiment, the X direction is exemplified as the direction representing "side". In the example of FIG. 1, the light-emitting element 1 has one bank BK on the side in the positive X direction (to the right in the plane of FIG. 1) relative to the EL light-emitting layer E. And the light-emitting element 1 has another bank BK on the side in the negative X direction (to the left in the plane of FIG. 1) relative to the EL light-emitting layer E.

The bank BK may contain any PL material MP that emits PL light 82. For this reason, the bank BK may be referred to as a PL bank. As shown in FIG. 1 , a part of the EL light 81 emitted from the EL light-emitting layer E may enter the inside of the bank BK located on the side of the EL light-emitting layer E. In addition, the PL material MP may absorb light of wavelength λ _{EL_PEAK} . Therefore, for example, the PL material MP absorbs the EL light 81 and emits PL light 82.

As an example, a part of the EL light 81 emitted from the EL layer E is incident on the upper electrode UE at a relatively large angle of incidence. The EL light 81 is totally reflected by the upper electrode UE and directed toward the inside of the bank BK. Therefore, by positioning the bank BK on the side of the EL layer E, the EL light 81 can be effectively received by the bank BK. As a result, the PL light 82 can be effectively generated in the bank BK. In this specification, the main peak wavelength of the PL light (e.g., the PL light 82) is represented as λ _{PL_PEAK} . The main peak wavelength of the PL light is also referred to as the PL main peak wavelength.

Unlike conventional light-emitting elements, light-emitting element 1 can generate PL light 82 by utilizing the component of EL light 81 that is not emitted to the outside of light-emitting element 1. Therefore, by extracting PL light 82 to the outside of light-emitting element 1, it is possible to achieve a higher light extraction efficiency than conventional light-emitting elements.

In conventional light-emitting elements, when EL light is converted to generate PL light, it is common to make the color of the PL light different from the color of the EL light. In contrast, in embodiment 1, the light-emitting element 1 is configured so that the color of the PL light 82 is as close as possible to the color of the EL light 81. This is because the closer the color of the PL light 82 is to the color of the EL light 81, the more improved the color purity of the light extracted to the outside of the light-emitting element 1 (i.e., the mixed light of the EL light 81 and the PL light 82).

Therefore, in the first embodiment, the light-emitting element 1 is configured so that λ _{PL_PEAK} is as close as possible to λ _{EL_PEAK} . Specifically, the light-emitting element 1 is configured such that the following formula (1):
λ _{PL_PEAK} -30nm≦λ _{EL_PEAK} ≦λ _{PL_PEAK} +10nm …(1)
The EL and PL materials MP are selected such that:

In general, a PL material converts EL light having a certain EL main peak wavelength into PL light having a PL main peak wavelength that is greater than the EL main peak wavelength. Therefore, the light-emitting element 1 also has a structure represented by the following formula (2):
λ _{EL_PEAK} <λ _{PL_PEAK} …(2)
can be satisfied.

However, depending on the spectrum of the EL light, for example, the PL material may be excited by EL light having an EL main peak wavelength larger than the PL main peak wavelength, and for this reason, it is assumed in equation (1) that λ _{PL_PEAK} can be smaller than λ _{EL_PEAK} .

By configuring the light-emitting element 1 so that formula (1) is satisfied, the color purity of the light extracted to the outside of the light-emitting element 1 can be improved compared to the conventional case. In addition, the brightness of the light extracted to the outside of the light-emitting element 1 can also be improved compared to the conventional case. As described above, the light-emitting element 1 can improve the performance of the light-emitting element through a new configuration that differs from the conventional case.

Furthermore, by configuring the light-emitting element 1 so that formula (2) is satisfied, the PL material MP can be excited more effectively by the EL light 81. In other words, the EL light 81 can be more effectively used to generate the PL light 82. Therefore, it is preferable that the light-emitting element 1 is configured so that formula (2) is satisfied.

Preferably, the EL light 81 has a single peak wavelength. When the EL light 81 has a single peak wavelength, the PL material is less likely to be excited by components of the EL light 81 that have excess energy, compared to when the EL light 81 has multiple peak wavelengths. This makes it possible to reduce the amount of heat generated when the PL material emits the PL light 82. As a result, the stability of the light-emitting element 1 can be improved.

When the EL light 81 has a single peak wavelength, it is desirable that the half-width in the emission spectrum of the EL light 81 is as small as possible. This is because the smaller the half-width, the less likely it is that the PL material will be excited by components of the EL light 81 that have excess energy. As an example, the half-width may be 40 nm or less. In this case, the amount of heat generated when the PL material emits the PL light 82 can be further reduced, thereby further improving the stability of the light-emitting element 1.

As described above, the bank BK has insulating properties. Therefore, the bank BK may contain any insulating material. Thus, for example, the bank BK may contain a resin. As an example, the resin content in the bank BK may be 30 weight percent or more.

The resin in the bank BK may be a photocurable resin. By using a photocurable resin, the manufacture of the light-emitting element 1 by an optical process (e.g., photolithography) is facilitated. Therefore, by using a photocurable resin, the mass productivity of the light-emitting element 1 can be improved.

In addition, by increasing the thickness of the bank BK, the insulating properties of the bank BK can also be improved. As an example, the thickness of the bank BK may be 300 nm or more. By setting the thickness of the bank BK to 300 nm or more, it is possible to impart good insulating properties to the bank BK. As a result, current leakage in the light-emitting element 1 is reduced. Therefore, the light-emitting efficiency of the light-emitting element 1 is improved.

The bank BK may contain QDs (Quantum Dots) as the PL material MP. By using QDs as the PL material MP, the monochromaticity of the PL light 82 can be improved. Thus, the bank BK may contain a mixture of QDs and resin.

The bank BK may include PL core-shell QDs. In this case, for example, the PL core-shell QDs may have a PL core as the PL material MP and a PL shell covering the PL core.

The PL material MP is preferably insulating, unlike the EL light-emitting material. The PL shell may be formed in multiple layers. The PL core may be an insulator. As an example, the PL core is 10 nm or thicker than the PL shell. Examples of insulating materials for the PL core include silica and alumina.

The EL light-emitting layer E may also include EL core-shell QDs. In this case, for example, the EL core-shell QDs may have an EL core as the EL material and an EL shell that covers the EL core.

Unlike the bank BK, the EL light-emitting layer E does not need to be insulating. Rather, from the viewpoint of the electrical properties of the EL light-emitting layer E, it is preferable that the EL light-emitting layer E has a certain degree of conductivity. Therefore, for example, the thickness of the EL shell may be set to be smaller than the thickness of the PL shell. In other words, the thickness of the PL shell may be set to be larger than the thickness of the EL shell.

By setting the thickness of the EL shell small as described above, the electrical characteristics of the EL light-emitting layer E can be improved. On the other hand, by setting the thickness of the PL shell small as described above, the PL core can be more reliably protected from damage caused by resin mixing. In addition, concentration quenching in the PL core can be reduced. As a result, the PL light-emitting efficiency of the light-emitting element 1 can be improved.

From the viewpoint of facilitating the manufacture of the light-emitting element 1, it is preferable that the number of types of raw materials involved in the manufacture of the light-emitting element 1 is as small as possible. From this viewpoint, the PL material MP may be the same as the EL material.

From the viewpoint of reducing concentration quenching in the PL material MP, it is desirable that the content of the PL material MS in the bank BK is not too high. As an example, the content of the PL material MS in the bank BK may be less than 50 weight percent. By setting the content of the PL material MS in the bank BK in this manner, the PL luminous efficiency of the light-emitting element 1 can also be improved.

However, light reflection can occur at the interface between two objects that have the same refractive index. Therefore, the light-emitting element 1 can have multiple light-reflecting surfaces. In FIG. 1, a first light-reflecting surface RF1 and a second light-reflecting surface RF2 that are parallel to each other are shown as examples of light-reflecting surfaces. As an example, the first light-reflecting surface RF1 may be the interface between the upper electrode UE and air. The second light-reflecting surface RF2 may be the interface between the lower electrode LE and the substrate SB.

Therefore, as shown in FIG. 1, at least a portion of the bank BK can be sandwiched between the first light reflecting surface RF1 and the second light reflecting surface RF2. The first light reflecting surface RF1 and the second light reflecting surface RF2 will be described in more detail in the third embodiment described below.

[Embodiment 2]
Fig. 2 shows a configuration example of the light-emitting element 1 in the second embodiment. In the example of Fig. 2, the light-emitting element 1 has a planarization film FF in an EL emission region ELA. The EL emission region ELA refers to a region in the light-emitting element 1 where EL light 81 is emitted from the EL emission layer E upon receiving carrier injection from the upper electrode UE and the lower electrode LE. Therefore, the EL emission region ELA does not overlap with the bank BK when viewed from the Z direction.

In the example of FIG. 2, in the EL emission region ELA, the lower electrode LE is located above the planarization film FF. Therefore, as shown in FIG. 2, at least a part of the bank BK can be located below the lower electrode LE in the EL emission region ELA.

By positioning at least a portion of the bank BK below the lower electrode LE in the EL emission region ELA, the volume of the bank BK can be increased. This increases the distance that the EL light 81 travels within the bank BK, allowing the EL light 81 to be absorbed more effectively by the PL material MS in the bank BK. This improves the luminous efficiency of the light-emitting element 1.

In addition, by positioning at least a portion of the bank BK below the lower electrode LE in the EL light-emitting region ELA, the upward protrusion length of the bank BK can be reduced even if the bank BK has a large thickness.

[Embodiment 3]
3 shows a configuration example of the light-emitting element 1 in embodiment 3. The light-emitting element 1 in embodiment 3 has a metal reflective film MF located above or below the bank BK. The upper electrode UE or the lower electrode LE can be used as the metal reflective film MF. In FIG. 3, as an example, a case is shown in which the lower electrode LE is the metal reflective film MF. The metal reflective film MF may be provided as a component separate from the upper electrode UE and the lower electrode LE.

The light-emitting element 1 in embodiment 3 has a light-transmitting film TF located between the bank BK and the metal reflective film MF. In the example of FIG. 3, the light-transmitting film TF is located between the bank BK and the lower electrode LE.

In the example of FIG. 3, as in the example of FIG. 1, a first light reflecting surface RF1 and a second light reflecting surface RF2 that are parallel to each other are shown. In the example of FIG. 3, at least a portion of the bank BK can be sandwiched between the first light reflecting surface RF1 and the second light reflecting surface RF2.

This positional relationship allows the first light reflecting surface RF1 and the second light reflecting surface RF2 to reinforce the main peak wavelength component of the PL light 82 in the Z direction. For example, the first light reflecting surface RF1 and the second light reflecting surface RF2 can reinforce the main peak wavelength component of the PL light 82 due to the resonance effect. As a result, the brightness of the PL light 82 emitted to the outside of the light-emitting element 1 can be improved.

The resonant structure formed by the first light reflecting surface RF1 and the second light reflecting surface RF2 can intensify the light. If the resonant structure completely intensifies the light, the following formula (3) holds:

In formula (3), m is the order of resonance. θ _D represents the phase shift due to reflection at the second light reflecting surface RF2. θ _U represents the phase shift due to reflection at the first light reflecting surface RF1. λ is the peak wavelength of light. n is the refractive index of the intermediate layer located between the first light reflecting surface RF1 and the second light reflecting surface RF2. d is the distance between the first light reflecting surface RF1 and the second light reflecting surface RF2 in the normal direction of the first light reflecting surface RF1 and the second light reflecting surface RF2, which are parallel to each other. φ is the angle formed between either the first light reflecting surface RF1 or the second light reflecting surface RF2, which are parallel to each other (e.g., the second light reflecting surface RF2), and the substrate SB.

The above-mentioned resonant structure may also attenuate light. If the resonant structure completely attenuates light, the following equation (4) holds: Equation (4) is a counterpart to equation (3).

In the third embodiment, θ _D and θ _U are set so that the order m corresponding to a certain distance d in formula (3) is a natural number. That is, in the third embodiment, θ _D and θ _U are set so that the following formula (5) is established.

In this specification, the value of the distance d when formula (3) is satisfied in the order m is denoted as _Dm . Also, the value of the distance d when formula (4) is satisfied in the order m is denoted as _dm . In a resonant structure that intensifies light, it is preferable that the following formula (6-1) is satisfied, it is more preferable that the following formula (6-2) is satisfied, and it is even more preferable that the following formula (6-3) is satisfied. When formulas (6-1) to (6-3) are generalized using a natural number k, it is as shown in the following formula (6-4).

Equations (6-1), (6-2), and (6-3) correspond to the cases of k=1, k=2, and k=4 in equation (6-4), respectively. As can be seen from this, in a resonant structure that intensifies light, it is preferable for equation (6-4) to hold for a larger k.

On the other hand, in a resonant structure that weakens light, it is preferable that the following formula (7-1) holds, it is more preferable that the following formula (7-2) holds, and it is even more preferable that the following formula (7-3) holds. When formulas (7-1) to (7-3) are generalized using a natural number k, it is as shown in the following formula (7-4). Formula (7-4) is a paired formula with formula (6-4).

Equations (7-1), (7-2), and (7-3) correspond to the cases of k=1, k=2, and k=4 in equation (7-4), respectively. As can be seen from this, in a resonant structure that attenuates light, it is preferable for equation (7-4) to hold for a larger k.

From the above, by using equation (6-4), it is possible to mathematically evaluate how the first light reflecting surface RF1 and the second light reflecting surface RF2 strengthen the main peak wavelength component of the PL light 82. Also, by using equation (7-4), it is possible to mathematically evaluate how the first light reflecting surface RF1 and the second light reflecting surface RF2 weaken the main peak wavelength component of the PL light 82.

Referring again to FIG. 3, the above-mentioned light-transmitting film TF can reduce plasmon absorption in the metal reflective film MF. Therefore, the light extraction efficiency of the PL light 82 in the light-emitting element 1 can be improved.

In the light-emitting element 1, the bank BK may be manufactured using a material that does not have light scattering properties. With a bank BK that does not have light scattering properties, for example, scattering of the PL light 82 can be prevented in the region sandwiched between the first light reflecting surface RF1 and the second light reflecting surface RF2. When scattering of the PL light 82 does not occur, the coherence of the PL light 82 is improved, and the first light reflecting surface RF1 and the second light reflecting surface RF2 can reinforce the main peak wavelength component of the PL light 82 more effectively.

From the viewpoint of improving the coherence of the PL light 82, it is preferable that the refractive index in the region sandwiched between the first light reflecting surface RF1 and the second light reflecting surface RF2 is as constant as possible. As an example, in the light-emitting element 1, each part belonging to the region sandwiched between the first light reflecting surface RF1 and the second light reflecting surface RF2 may have a constant refractive index when observed on a scale longer than half the main peak wavelength of the PL light (i.e., λ _{PL_PEAK} /2). If this condition is satisfied, the coherence of the PL light 82 can be further improved.

In order for the first light reflecting surface RF1 and the second light reflecting surface RF2 to effectively reinforce the PL light 82, it is preferable that the first light reflecting surface RF1 and the second light reflecting surface RF2 are not too far apart. Therefore, for example, the distance between the first light reflecting surface RF1 and the second light reflecting surface RF2 may be greater than 0 μm and equal to or less than 1 μm.

FIG. 4 is a diagram explaining the relationship between the angle of the PL light 82 (more specifically, the angle of the optical axis of the PL light 82) and the radiance. In this specification, the angle that the PL light 82 makes with respect to the Z direction is represented as θ. The radiance of the PL light 82 that makes an angle θ with respect to the Z direction is represented as RM(θ).

In FIG. 4, the case where 0°≦θ≦90° is illustrated. In the example of FIG. 4, when θ=0°, the direction of the PL light 82 coincides with the positive direction of the Z direction. On the other hand, when θ=90°, the direction of the PL light 82 coincides with the positive direction of the X direction.

As shown in Figure 4, consider two angles θ1 and θ2 that satisfy the relationship θ1 < θ2. In the example of Figure 4, PL light 82A forms an angle θ1, and PL light 82B forms an angle θ2. In the light-emitting element 1, as θ increases, the mismatch between the direction of PL light 82 and the Z direction becomes more pronounced. Therefore, as θ increases, it becomes more difficult for the first light reflecting surface RF1 and the second light reflecting surface RF2 to intensify the PL light 82.

As a result, in the light-emitting element 1, RM(θ) can decrease significantly with an increase in θ. Therefore, in the light-emitting element 1, for example, in the range of 0°≦θ1<θ2<70°, the following formula (8):
RM(θ2)/RM(θ1)≦0.7…(8)
There may exist θ1 and θ2 that satisfy the following:

[Embodiment 4]
Fig. 5 shows an example of the configuration of the light-emitting element 1 in embodiment 4. In the example of Fig. 5, the bank BK has a non-light-emitting portion NE inside the bank BK. Therefore, in the example of Fig. 5, the light-emitting portion of the bank BK (the portion including the PL material MP) is located outside the bank BK. The symbol SS in Fig. 5 represents the slope of the bank BK. The slope SS in the example of Fig. 5 is the outer slope of the bank BK, i.e., the slope of the light-emitting portion of the bank BK.

In the example of FIG. 5, a first light reflecting surface RF1 and a second light reflecting surface RF are shown positioned on either side of the inclined surface SS. In this manner, the inclined surface SS can be positioned between the first light reflecting surface RF1 and the second light reflecting surface RF2.

As an example, the surface of the non-light-emitting portion NE may be light-reflective. Therefore, the second light-reflecting surface RF2 in FIG. 5 may be, for example, the interface between the non-light-emitting portion NE and the light-emitting portion of the bank BK.

Since the inclined surface SS is located between the first light reflecting surface RF1 and the second light reflecting surface RF, the PL light 82 generated near the inclined surface SS can be reinforced by the first light reflecting surface RF1 and the second light reflecting surface RF. For example, the main peak wavelength component of the PL light 82 in the Z direction can be reinforced by the first light reflecting surface RF1 and the second light reflecting surface RF.

As shown in FIG. 5, the thickness of the non-emitting portion NE of the bank BK may be set to be greater than the thickness of the EL light-emitting layer E. This allows the main peak wavelength component of the PL light 82 in the Z direction to be reinforced more effectively by the first light reflecting surface RF1 and the second light reflecting surface RF.

[Embodiment 5]
Fig. 6 shows a configuration example of the light emitting device 10 in embodiment 5. Reference numeral 610 in Fig. 6 typically indicates a cross-sectional structure of the light emitting device 10, and reference numeral 620 typically indicates a planar layout of the light emitting device 10. The light emitting device according to one aspect of the present disclosure may include a light emitting element according to one aspect of the present disclosure. In embodiment 5, a case in which the light emitting device 10 includes a plurality of light emitting elements 1 is illustrated.

As shown in FIG. 6, the light emitting device 10 may have a first light emitting element 1-1 and a second light emitting element 1-2 adjacent to the first light emitting element 1-1 as the multiple light emitting elements 1. In this specification, "adjacent" refers to "adjacent in the lateral direction (X direction)" unless otherwise specified.

The first light-emitting element 1-1 has a first upper electrode UE1 as the upper electrode UE and a first lower electrode LE1 as the lower electrode LE. The first light-emitting element 1-1 has a first EL light-emitting layer E1 as the EL light-emitting layer E. The first EL light-emitting layer E1 emits first EL light upon receiving carrier injection from the first upper electrode UE1 and the first lower electrode LE1. The first light-emitting element 1-1 has a first bank BK1 as the bank BK. The first bank BK1 is located to the side of the first EL light-emitting layer E1.

The second light-emitting element 1-2 has a second upper electrode UE2 as the upper electrode UE and a second lower electrode LE2 as the lower electrode LE. The second light-emitting element 1-2 has a second EL light-emitting layer E2 as the EL light-emitting layer E. The second EL light-emitting layer E2 receives carrier injection from the second upper electrode UE2 and the second lower electrode LE2 and emits second EL light. The second light-emitting element 1-2 has a second bank BK2 as the bank BK. The second bank BK2 is located to the side of the second EL light-emitting layer E2.

As shown in FIG. 6, the first bank BK1 and the second bank BK2 are located between the first EL light-emitting layer E1 and the second EL light-emitting layer E2. In other words, the first EL light-emitting layer E1 and the second EL light-emitting layer E2 are partitioned by the first bank BK1 and the second bank BK2.

In this specification, the main peak wavelength of the first EL light is referred to as the first EL main peak wavelength, and the main peak wavelength of the second EL light is referred to as the first EL main peak wavelength. In a light emitting device according to one aspect of the present disclosure, the first EL main peak wavelength and the second EL main peak wavelength may be the same or different.

In embodiment 5, a case where the first EL main peak wavelength and the second EL main peak wavelength are different is illustrated. Specifically, in embodiment 5, a case where the first EL main peak wavelength is longer than the second EL main peak wavelength is illustrated.

In embodiment 5, a case is illustrated in which each of multiple banks BK (e.g., a first bank BK1 and a second bank BK2) contains a different PL material MP. In embodiment 5, the first bank BK1 contains a first PL material MP1 as the PL material MP. The first PL material MP1 absorbs the first EL light and emits the first PL light. The second bank BK2 contains a second PL material MP2 as the PL material MP. The second PL material MP2 absorbs the second EL light and emits the second PL light.

In this specification, the main peak wavelength of the first PL light is referred to as the first PL main peak wavelength, and the main peak wavelength of the second PL light is referred to as the first PL main peak wavelength. In the example of embodiment 5, the first PL main peak wavelength is longer than the second PL main peak wavelength.

Generally, the distance between the first light reflecting surface RF1 and the second light reflecting surface RF2 for strengthening a certain PL light by the resonance effect increases as the main peak wavelength of the PL light increases. For this reason, in the example of FIG. 6, the height of the first bank BK1 is set to be greater than the height of the second bank BK2. This makes it possible to strengthen the first PL light by the resonance effect in the first bank BK1, and to strengthen the second PL light by the resonance effect in the second bank BK2.

FIG. 7 shows another example of the configuration of the light-emitting device 10 in embodiment 5. Reference numeral 710 in FIG. 7 typically indicates the cross-sectional structure of the light-emitting device 10, and reference numeral 720 typically indicates the planar layout of the light-emitting device 10. The light-emitting device 10 in the example of FIG. 7 further includes a third light-emitting element 1-3 as a plurality of light-emitting elements 1. The third light-emitting element 1-3 is adjacent to the second light-emitting element 1-2 on the side opposite to the first light-emitting element 1-1.

The third light-emitting element 1-3 has a third upper electrode UE3 as the upper electrode UE and a third lower electrode LE3 as the lower electrode LE. The third light-emitting element 1-3 has a third EL light-emitting layer E3 as the EL light-emitting layer E. The third EL light-emitting layer E3 receives carrier injection from the third upper electrode UE3 and the third lower electrode LE3 and emits third EL light. The third light-emitting element 1-3 has a third bank BK3 as the bank BK. The third bank BK3 is located to the side of the third EL light-emitting layer E3.

As shown in FIG. 7, the second bank BK2 and the third bank BK3 are located between the second EL light-emitting layer E2 and the third EL light-emitting layer E3. In other words, the second EL light-emitting layer E2 and the third EL light-emitting layer E3 are partitioned by the second bank BK2 and the third bank BK3.

In this specification, the main peak wavelength of the third EL light is referred to as the third EL main peak wavelength. In the fifth embodiment, a case is exemplified in which the second EL main peak wavelength is longer than the third EL main peak wavelength. Thus, in the fifth embodiment, the third EL main peak wavelength is shorter than the second EL main peak wavelength, and the second EL main peak wavelength is shorter than the first EL main peak wavelength.

In embodiment 5, the third bank BK3 contains a third PL material MP3 as the PL material MP. The third PL material MP3 absorbs the third EL light and emits the third PL light. In the example of embodiment 5, the second PL main peak wavelength is longer than the third PL main peak wavelength. Thus, in embodiment 5, the third PL main peak wavelength is shorter than the second PL main peak wavelength, and the second PL main peak wavelength is shorter than the first PL main peak wavelength.

In the example of FIG. 7, the height of the second bank BK2 is set to be greater than the height of the third bank BK3. Thus, in embodiment 5, the height of the third bank BK3 is smaller than the height of the second bank BK2, and the height of the second bank BK2 is smaller than the height of the first bank BK1.

As an example, in FIG. 7, the first EL light may be red EL light, the second EL light may be green EL light, and the third EL light may be blue EL light. Thus, the first EL light-emitting layer E1 may be a red EL light-emitting layer, the second EL light-emitting layer E2 may be a green EL light-emitting layer, and the third EL light-emitting layer E3 may be a blue EL light-emitting layer.

In this case, for example, the first PL light may be red PL light, the second EL light may be green PL light, and the third EL light may be blue PL light. Thus, the first PL material MP1 may be a red PL material, the second PL material MP2 may be a green PL material, and the third PL material MP3 may be a blue PL material.

As described above, the first light-emitting element 1-1 may be a red light-emitting element, the second light-emitting element 1-2 may be a green light-emitting element, and the third light-emitting element 1-3 may be a blue light-emitting element. In this case, for example, the first EL main peak wavelength may be 630 nm, and the first PL main peak wavelength may be 640 nm. The second EL main peak wavelength may be 530 nm, and the second PL main peak wavelength may be 540 nm. The third EL main peak wavelength may be 460 nm, and the third PL main peak wavelength may be 470 nm.

[Embodiment 6]
Fig. 8 shows an example of a configuration of the light-emitting device 10 in embodiment 6. Like Fig. 6, Fig. 8 shows a light-emitting device 10 having two types of light-emitting elements, a first light-emitting element 1-1 and a second light-emitting element 1-2. Reference numeral 810 in Fig. 8 typically indicates a cross-sectional structure of the light-emitting device 10, and reference numeral 820 typically indicates a planar layout of the light-emitting device 10.

In the sixth embodiment, unlike the fifth embodiment, each of the multiple banks BK (e.g., the first bank BK1 and the second bank BK2) contains the same PL material MP. In this case, the manufacturing of the multiple banks BK is easier than in the fifth embodiment. Furthermore, the brightness of the PL light emitted from the light emitting device 10 can be increased.

In embodiment 6, an example is shown in which the first bank BK1 and the second bank BK2 each contain a PL material MP that absorbs the second EL light and emits PL light. The PL main peak wavelength in embodiment 6 is preferably longer than the second EL main peak wavelength and shorter than the first EL main peak wavelength. In this case, for example, the PL material MP can be excited only by the second EL light. In other words, the PL material MP is not excited by the first EL light. Therefore, the risk of color mixing caused by the PL light in the light emitting device 10 can be reduced.

As described above, in embodiment 6, the first bank BK1 and the second bank BK each contain the same PL material MP. For this reason, in the example of FIG. 8, the height of the first bank BK1 is set to be the same as the height of the second bank BK2.

As shown in FIG. 8, the light emitting device 10 may have a conductive reflective film CR. Two adjacent banks BK (e.g., a first bank BK1 and a second bank BK2) may form a valley portion VL between the two BKs. In the example of FIG. 8, the conductive reflective film CR is located on the upper surface of the valley portion VL between the first bank BK1 and the second bank BK2.

The conductive reflective film CR in FIG. 8 can reduce the resistance of the upper electrode UE. This can improve the EL light emission efficiency in the light emitting device 10. The conductive reflective film CR in FIG. 8 can also reduce the risk of color mixing caused by PL light in the light emitting device 10.

FIG. 9 shows another example of the configuration of the light-emitting device 10 in embodiment 6. As in FIG. 7, FIG. 9 shows an example of a light-emitting device 10 having three types of light-emitting elements, a first light-emitting element 1-1, a second light-emitting element 1-2, and a third light-emitting element 1-3. Reference numeral 910 in FIG. 9 shows a schematic cross-sectional structure of the light-emitting device 10, and reference numeral 920 shows a schematic planar layout of the light-emitting device 10.

The example of Figure 9 illustrates a case in which the first bank BK1, the second bank BK2, and the third bank BK3 each contain a PL material MP that absorbs the third EL light and emits PL light. The PL main peak wavelength in the example of Figure 9 is preferably longer than the third EL main peak wavelength and shorter than the second EL main peak wavelength. In this case, for example, the PL material MP can be excited only by the third EL light. In other words, it is possible to prevent the PL material MP from being excited by either the first EL light or the second EL light.

As shown in FIG. 9, the second bank BK2 and the third bank BK3 can form a valley portion VL between the second bank BK2 and the third bank BK3. In the example of FIG. 9, the conductive reflective film CR is also located on the upper surface of the valley portion VL between the second bank BK2 and the third bank BK3.

As an example, consider the case in FIG. 9 where the first EL light-emitting layer E1 is a red EL light-emitting layer, the second EL light-emitting layer E2 is a green EL light-emitting layer, and the third EL light-emitting layer E3 is a blue EL light-emitting layer. In this case, for example, the PL light may be blue PL light. Therefore, the PL material MP may be a blue PL material.

As described above, even when one type of PL material (e.g., blue PL material) is used, it is possible to realize a first light-emitting element 1-1 as a red light-emitting element, a second light-emitting element 1-2 as a green light-emitting element, and a third light-emitting element 1-3 as a blue light-emitting element. In this case, for example, the first EL main peak wavelength may be 630 nm, the second EL main peak wavelength may be 530 nm, and the third EL main peak wavelength may be 460 nm. And the PL main peak wavelength may be 470 nm.

[Embodiment 7]
Fig. 10 shows a configuration example of the light emitting device 10 in embodiment 7. Like Fig. 6, Fig. 10 shows a light emitting device 10 having two types of light emitting elements, a first light emitting element 1-1 and a second light emitting element 1-2. Reference numeral 1010 in Fig. 10 typically indicates a cross-sectional structure of the light emitting device 10, and reference numeral 1020 typically indicates a planar layout of the light emitting device 10.

In the seventh embodiment, as in the fifth embodiment, an example is shown in which each of the multiple banks BK contains a different PL material MP. In the example of FIG. 10, as in the example of FIG. 6, the first bank BK1 contains the first PL material MP1, and the second bank BK2 contains the second PL material MP2. Therefore, in the example of FIG. 10, as in the example of FIG. 6, the height of the first bank BK1 is greater than the height of the second bank BK2.

In the seventh embodiment, as in the sixth embodiment, the light emitting device 10 has a conductive reflective film CR. In the example of FIG. 10, the conductive reflective film CR is located on the upper surface of the valley portion VL between the first bank BK1 and the second bank BK2. In this way, the conductive reflective film CR may be provided even when the height of the first bank BK1 and the height of the second bank BK2 are different.

FIG. 11 shows another example of the configuration of the light-emitting device 10 in embodiment 7. As in FIG. 7, FIG. 11 shows an example of a light-emitting device 10 having three types of light-emitting elements, a first light-emitting element 1-1, a second light-emitting element 1-2, and a third light-emitting element 1-3. Reference numeral 1110 in FIG. 11 shows a schematic cross-sectional structure of the light-emitting device 10, and reference numeral 1120 shows a schematic planar layout of the light-emitting device 10.

In the example of FIG. 11, like the example of FIG. 7, the third bank BK3 contains the third PL material MP3. Therefore, in the example of FIG. 11, like the example of FIG. 7, the height of the second bank BK2 is greater than the height of the third bank BK3. In the example of FIG. 11, the conductive reflective film CR is also located on the upper surface of the valley portion VL between the second bank BK2 and the third bank BK3.

[Embodiment 8]
Fig. 12 shows an example of a configuration of the light emitting device 10 in the eighth embodiment. As in Fig. 6, Fig. 12 shows a light emitting device 10 having two types of light emitting elements, a first light emitting element 1-1 and a second light emitting element 1-2. Reference numeral 1210 in Fig. 12 typically indicates a cross-sectional structure of the light emitting device 10, and reference numeral 1220 typically indicates a planar layout of the light emitting device 10.

In the eighth embodiment, as in the sixth embodiment, an example is shown in which each of the multiple banks BK contains the same PL material MP. In the example of FIG. 12, as in the example of FIG. 8, the first bank BK1 and the second bank BK2 each contain a PL material MP that absorbs the second EL light and emits PL light. Therefore, in the example of FIG. 12, as in the example of FIG. 8, the first bank BK1 and the second bank BK2 each have the same height.

In the example of FIG. 12, unlike the example of FIG. 8, two adjacent banks BK do not form a valley portion VL between the two BK. In this case, as shown in FIG. 12, the light emitting device 10 does not need to have a conductive reflective film CR. In this way, the configuration of the light emitting device 10 can be further simplified compared to the example of FIG. 8.

FIG. 13 shows another example of the configuration of the light-emitting device 10 in embodiment 8. As in FIG. 7, FIG. 13 shows an example of a light-emitting device 10 having three types of light-emitting elements, a first light-emitting element 1-1, a second light-emitting element 1-2, and a third light-emitting element 1-3. Reference numeral 1310 in FIG. 13 shows a schematic cross-sectional structure of the light-emitting device 10, and reference numeral 1320 shows a schematic planar layout of the light-emitting device 10.

In the example of FIG. 13, like the example of FIG. 8, the first bank BK1, the second bank BK2, and the third bank BK3 each contain a PL material MP that absorbs the third EL light and emits PL light. Therefore, in the example of FIG. 13, like the example of FIG. 8, the first bank BK1, the second bank BK2, and the third bank BK3 each have the same height.

In the example of FIG. 13, unlike the example of FIG. 9, two adjacent banks BK do not form a valley portion VL between the two BK. Therefore, the light-emitting device 10 in the example of FIG. 13 does not need to have a conductive reflective film CR. In this way, the configuration of the light-emitting device 10 can be further simplified compared to the example of FIG. 9.

[Embodiment 9]
Fig. 14 shows an example of a configuration of the light emitting device 10 in the ninth embodiment. The light emitting device 10 in Fig. 14 is a variation of the light emitting device 10 in Fig. 12. Reference numeral 1410 in Fig. 14 typically indicates a cross-sectional structure of the light emitting device 10, and reference numeral 1420 typically indicates a planar layout of the light emitting device 10.

The symbol SS1 in FIG. 14 indicates the slope of the first bank BK1 that slopes in the direction from the second EL light-emitting layer E2 to the first EL light-emitting layer E1 (i.e., in the negative direction of the X direction).

The light emitting device 10 in the example of FIG. 14 has a conductive reflective film CRU, unlike the example of FIG. 12. As shown in FIG. 14, the conductive reflective film CRU may be located on the upper side of the slope SS1. The conductive reflective film CRU can reduce the risk of color mixing caused by PL light in the light emitting device 10.

FIG. 15 shows another example of the configuration of the light-emitting device 10 in embodiment 9. The light-emitting device 10 in FIG. 15 is a variation of the light-emitting device 10 in FIG. 13. Reference numeral 1510 in FIG. 15 typically indicates the cross-sectional structure of the light-emitting device 10, and reference numeral 1520 typically indicates the planar layout of the light-emitting device 10.

The symbol SS2 in FIG. 15 indicates the slope of the second bank BK2 that slopes in the direction from the third EL light-emitting layer E3 toward the second EL light-emitting layer E2 (i.e., in the negative direction of the X direction).

The light emitting device 10 in the example of FIG. 15 also has a conductive reflective film CRU, as in the example of FIG. 14. As shown in FIG. 15, the conductive reflective film CRU may be located above the slope SS2.

In the example of FIG. 15, the PL main peak wavelength is 470 nm. The first EL main peak wavelength is 630 nm, the second EL main peak wavelength is 530 nm, and the third EL main peak wavelength is 460 nm. Thus, in the example of FIG. 15, the PL main peak wavelength is longer than the third EL main peak wavelength and shorter than the second EL main peak wavelength and the first EL main peak wavelength.

As described above, when the PL main peak wavelength is longer than the third EL main peak wavelength and shorter than the second EL main peak wavelength and the first EL main peak wavelength, the PL material MP can be excited only by the third EL light. In other words, it is possible to prevent the PL material MP from being excited by either the first EL light or the second EL light. For this reason, as shown by the reference numeral 1520, the light emitting device 10 in the example of FIG. 15 does not need to have a conductive reflective film CRU between the first EL light emitting layer E1 and the second EL light emitting layer E2.

As shown by reference numeral 1520, in the light emitting device 10, the first light emitting element 1-1, the second light emitting element 1-2, and the third light emitting element 1-3 may be repeatedly arranged in this order in the X direction. Therefore, the light emitting device 10 in FIG. 15 may have a third light emitting element 1-3A in addition to the one third light emitting element 1-3. In the example of reference numeral 1510, the third light emitting element 1-3A is adjacent to the first light emitting element 1-1 on the negative side of the X direction. In this way, the third light emitting element 1-3A is adjacent to the first light emitting element 1-1 on the side opposite to the second light emitting element 1-2.

In the example of FIG. 15, the third bank of the third light-emitting element 1-3A is written as the third bank BK3A. Also, the third EL light-emitting layer of the third light-emitting element 1-3A is written as the third EL light-emitting layer E3A. As is clear from FIG. 15, the first bank BK1 and the third bank BK3A are located between the first EL light-emitting layer E1 and the third EL light-emitting layer 3EA (not shown in the diagram of reference numeral 1510).

The symbol SS1A in FIG. 15 indicates the slope of the first bank BK1 that slopes in the direction from the third EL light-emitting layer E3A toward the first EL light-emitting layer E1 (i.e., in the positive direction of the X direction). In the example of FIG. 15, the conductive reflective film CRU is also located above the slope SS1A.

[Embodiment 10]
16 illustrates a configuration example of a display device 100 according to embodiment 10. The display device 100 may include a light-emitting device according to one aspect of the present disclosure (e.g., light-emitting device 10). Thus, the display device 100 may include a light-emitting element according to one aspect of the present disclosure (e.g., light-emitting element 1).

The display device 100 may include a display unit DA including a plurality of subpixels SP, a first driver X1 and a second driver X2 that drive the plurality of subpixels SP, and a display controller DC that controls the first driver X1 and the second driver X2. The subpixel SP may include a light-emitting element 1 and a pixel circuit PC connected to the light-emitting element 1. The display device 100 may include a first light-emitting element 1-1, a second light-emitting element 1-2, and a third light-emitting element 1-3 as the light-emitting element 1.

The pixel circuit PC may be connected to a scanning signal line GL, a data signal line DL, and an emission control line ELL. As an example, the scanning signal line GL and the emission control line ELL may be connected to a first driver X1. The data signal line DL may be connected to a second driver X2.

[Additional Notes]
One aspect of the present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Also, embodiments obtained by appropriately combining the technical means disclosed in different embodiments are included in the technical scope of one aspect of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

1 Light-emitting element 1-1 First light-emitting element 1-2 Second light-emitting element 1-3 Third light-emitting element 1-3A Another third light-emitting element 10 Light-emitting device 81 EL light 82 PL light 100 Display device UE Upper electrode UE1 First upper electrode UE2 Second upper electrode UE3 Third upper electrode LE Lower electrode LE1 First lower electrode LE2 Second lower electrode LE3 Third lower electrode E EL light-emitting layer E1 First EL light-emitting layer E2 Second EL light-emitting layer E3 Third EL light-emitting layer E3A Third EL light-emitting layer of another third light-emitting element ELA EL light-emitting region BK Bank BK1 First bank BK2 Second bank BK3 Third bank MP PL material MP1 First PL material MP2 Second PL material MP3 Third PL material MF Metal reflective film TF Light-transmitting film RF1 First light reflecting surface RF2 Second light reflecting surface SS Slope of bank SS1 Slope of first bank (slope inclined along the direction from the second EL light emitting layer to the first EL light emitting layer)
SS1A: Slope of the second bank (slope inclined along the direction from the third EL layer of another third light-emitting element to the first EL layer)
SS2: Slope of the second bank (slope inclined along the direction from the third EL layer to the second EL layer)
VL: Valley portion CR: Conductive reflective film (conductive reflective film located on the upper surface of the valley portion)
CRU: Conductive reflective film (conductive reflective film located on the upper side of the slope of the bank)

Claims (34)

an upper electrode and a lower electrode facing each other;
an electroluminescence (EL) layer that emits EL light upon receiving carrier injection from the upper electrode and the lower electrode;
an insulating bank located on a side of the EL light-emitting layer;
At least one of the upper electrode and the lower electrode is a light-transmitting electrode,
The bank contains a PL (Photo-Luminescence) material that emits PL light,
When the main peak wavelength of the EL light is denoted as λ _{EL_PEAK} and the main peak wavelength of the PL light is denoted as λ _{PL_PEAK} ,
The PL material absorbs light at wavelength λ _{EL_PEAK} ;
λ _{PL_PEAK} -30nm≦λ _{EL_PEAK} ≦λ _{PL_PEAK} +10nm
That is, a light-emitting element. λ _{EL_PEAK} <λ _{PL_PEAK}
The light-emitting device according to claim 1 , the bank includes a resin;
The light-emitting element according to claim 1 , wherein the content of the resin in the bank is 30 weight percent or more. The light-emitting element according to claim 3, wherein the resin is a photocurable resin. The light-emitting element according to claim 3 or 4, wherein the thickness of the bank is 300 nm or more. The light-emitting element according to any one of claims 1 to 5, wherein the bank contains QD (Quantum Dot) as the PL material. the EL emitting layer comprises EL core-shell QDs;
the bank comprises PL core-shell QDs;
The EL core-shell QD has an EL core as an EL material that emits the EL light, and an EL shell that covers the EL core,
The PL core-shell QD has a PL core as the PL material and a PL shell covering the PL core,
The light-emitting device of claim 6 , wherein the thickness of the PL shell is greater than the thickness of the EL shell. The light-emitting element according to any one of claims 1 to 7, wherein the EL light has a single peak wavelength. The light-emitting element according to claim 8, wherein the half-width of the emission spectrum of the EL light is 40 nm or less. The light-emitting device of any one of claims 1 to 9, wherein the content of the PL material in the bank is less than 50 weight percent. The light-emitting element according to any one of claims 1 to 10, wherein at least a portion of the bank is located below the lower electrode in the EL light-emitting region of the light-emitting element. a metal reflective film located above or below the bank;
The light-emitting element according to claim 1 , further comprising: a light-transmitting film located between the bank and the metal reflective film. The light-emitting element according to any one of claims 1 to 12, wherein at least a portion of the bank is sandwiched between a first light-reflecting surface and a second light-reflecting surface that are parallel to each other. The light-emitting element according to claim 13, wherein the PL light is not scattered in the area between the first light-reflecting surface and the second light-reflecting surface. The light-emitting element according to claim 13 or 14, wherein the refractive index is constant in each portion belonging to the region sandwiched between the first light reflecting surface and the second light reflecting surface when observed on a scale longer than half the main peak wavelength of the PL light. When the radiance of the PL light that forms an angle θ with respect to the normal direction of the horizontal plane of the substrate of the light emitting element is expressed as RM(θ),
In the range of 0°≦θ1<θ2<70°,
RM(θ2)/RM(θ1)≦0.7
The light-emitting device according to claim 13 , wherein angles θ1 and θ2 exist such that The light-emitting device of any one of claims 13 to 16, wherein the bank contains a mixture of QDs and resin. The light-emitting element according to any one of claims 13 to 17, wherein the first light-reflecting surface and the second light-reflecting surface reinforce the main peak wavelength component of the PL light in the normal direction to the horizontal plane of the substrate of the light-emitting element. The light-emitting element according to any one of claims 13 to 18, wherein the slope of the bank is located between the first light-reflecting surface and the second light-reflecting surface. the bank includes a non-light-emitting portion therein,
The light-emitting device of claim 19 , wherein the thickness of the non-light-emitting portion is greater than the thickness of the electroluminescent layer. The light-emitting element according to claim 20, wherein the surface of the non-light-emitting portion is light-reflective. The light-emitting element according to any one of claims 19 to 21, wherein the first light-reflecting surface and the second light-reflecting surface, which are located on either side of the inclined surface of the bank, reinforce each other with the main peak wavelength component of the PL light in the normal direction to the horizontal surface of the substrate of the light-emitting element. The light-emitting element according to any one of claims 13 to 22, wherein the distance between the first light-reflecting surface and the second light-reflecting surface is greater than 0 μm and less than or equal to 1 μm. A light-emitting device having a light-emitting element according to any one of claims 1 to 23. The light emitting device includes a first light emitting element and a second light emitting element adjacent to the first light emitting element as the plurality of light emitting elements,
The first light emitting element is
The upper electrode and the lower electrode include a first upper electrode and a first lower electrode, respectively;
a first EL light-emitting layer that receives carrier injection from the first upper electrode and the first lower electrode to emit a first EL light,
The bank includes a first bank located on a side of the first electroluminescent layer,
The second light emitting element is
The upper electrode and the lower electrode include a second upper electrode and a second lower electrode, respectively;
a second EL light-emitting layer that receives carrier injection from the second upper electrode and the second lower electrode to emit second EL light,
The bank includes a second bank located on a side of the first electroluminescent layer,
the first bank and the second bank are located between the first EL layer and the second EL layer;
The light emitting device of claim 24 , wherein a main peak wavelength of the first EL light is longer than a main peak wavelength of the second EL light. the first bank and the second bank form a valley between the first bank and the second bank,
26. The light emitting device of claim 25, further comprising a conductive reflective film located on an upper surface of the valley. The light emitting device according to claim 25 or 26, wherein the height of the first bank is the same as the height of the second bank. the first bank includes a first PL material that absorbs the first EL light and emits a first PL light;
the second bank includes a second PL material that absorbs the second EL light and emits a second PL light;
a main peak wavelength of the first PL light is longer than a main peak wavelength of the second PL light;
27. The light emitting device according to claim 25 or 26, wherein a height of the first bank is greater than a height of the second bank. the first bank and the second bank each include the PL material that absorbs the second EL light and emits the PL light;
The light emitting device of claim 25 , wherein a main peak wavelength of the PL light is longer than a main peak wavelength of the second EL light and shorter than a main peak wavelength of the first EL light. the first bank has a slope that slopes in a direction from the second EL layer toward the first EL layer,
30. The light emitting device of claim 29, further comprising a conductive reflective film located above the slope of the first bank. The light emitting device further includes a third light emitting element adjacent to the second light emitting element on an opposite side to the first light emitting element,
The third light emitting element is
The upper electrode and the lower electrode include a third upper electrode and a third lower electrode, respectively;
a third EL light-emitting layer that receives carrier injection from the third upper electrode and the third lower electrode to emit third EL light,
The bank includes a third bank located on a side of the third electroluminescent layer,
the second bank and the third bank are located between the second EL layer and the third EL layer,
a main peak wavelength of the second EL light is longer than a main peak wavelength of the third EL light;
the first bank, the second bank, and the third bank each include the PL material that absorbs the third EL light and emits the PL light;
The light emitting device of claim 25 , wherein a main peak wavelength of the PL light is longer than a main peak wavelength of the third EL light and shorter than a main peak wavelength of the second EL light. the second bank has a slope that slopes in a direction from the third EL layer toward the second EL layer,
32. The light emitting device of claim 31, further comprising a conductive reflective film located above the slope of the second bank. The light emitting device further includes, as the plurality of light emitting elements, a third light emitting element adjacent to the first light emitting element on an opposite side to the second light emitting element,
the first bank and the third bank of the third light-emitting element are located between the first EL layer and the third EL layer of the third light-emitting element,
the first bank has a slope that slopes along a direction from the third EL light-emitting layer of another third light-emitting element to the first EL light-emitting layer,
33. The light emitting device according to claim 32, further comprising a conductive reflective film located above the slope of the first bank. A display device having the light-emitting device according to any one of claims 24 to 33.