A light-emitting device with improved luminous efficiency and a display device including the light-emitting device.

Abstract

A light-emitting device includes: a reflective layer; a first electrode disposed on the reflective layer; a second electrode facing the first electrode; a first emitting layer disposed between the first electrode and the second electrode; a second emitting layer disposed between the first emitting layer and the second electrode; and a first partial transmissive mirror disposed between the first emitting layer and the second emitting layer, thereby forming a first or higher order resonant mode between the reflective layer and the first partial transmissive mirror, and forming a second or higher order resonant mode between the reflective layer and the second electrode.

Description

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2021-0028354, filed on March 3, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to a light-emitting device and a display device including the light-emitting device, and more specifically, to an organic light-emitting device (OLED) with improved luminous efficiency and an organic light-emitting display device. Background Technology

[0004] Organic light-emitting devices (OLEDs) form images by emitting light based on the combination of holes supplied from the anode in an organic emitting layer and electrons supplied from the cathode. OLEDs have excellent display characteristics, such as wide viewing angle, fast response speed, small thickness, low manufacturing cost, and high contrast.

[0005] Furthermore, OLEDs can emit specific colors by selecting appropriate materials as the organic emitting layer. Based on this principle, color display devices can be manufactured using OLEDs. Summary of the Invention

[0006] It provides OLED and organic light-emitting display devices with improved luminous efficiency.

[0007] Additional aspects will be set forth in part in the description which follows, and will also be apparent in part from the description, or may be learned by practice of embodiments of the present disclosure.

[0008] According to one aspect of an example embodiment, a light-emitting device is provided, comprising: a reflective layer; a first electrode disposed on the reflective layer; a second electrode facing the first electrode; a first emitting layer disposed between the first electrode and the second electrode; a second emitting layer disposed between the first emitting layer and the second electrode; and a first partial transmissive mirror disposed between the first emitting layer and the second emitting layer, such that a first or higher order resonant mode is formed between the reflective layer and the first partial transmissive mirror, and a second or higher order resonant mode is formed between the reflective layer and the second electrode.

[0009] The first electrode may include a transparent electrode, and the second electrode may include a partially transmissive electrode that reflects some light while transmitting other light.

[0010] The reflective layer and the second electrode can form a microcavity with a resonant wavelength, and the first portion of the transmission mirror can be disposed at the node of the light wave resonating within the microcavity.

[0011] The first part of the transmission mirror may include silver (Ag), aluminum (Al), silver alloy or aluminum alloy.

[0012] The thickness of the first part of the transmission mirror can be from about 5 nm to about 30 nm.

[0013] The thickness of the second electrode may be different from the thickness of the first part of the transmission mirror.

[0014] The first emitting layer may include: a first hole transport layer disposed on the first electrode; a first organic emitting material layer disposed on the first hole transport layer; and a first electron transport layer disposed on the first organic emitting material layer. The second emitting layer may include: a second hole transport layer disposed on the first partial transmission mirror; a second organic emitting material layer disposed on the second hole transport layer; and a second electron transport layer disposed on the second organic emitting material layer.

[0015] The light-emitting device may further include: a transparent conductor layer on the first portion of the transmission mirror, facing the second electrode.

[0016] The light-emitting device may further include a charge generation layer disposed between the first emitting layer and the second emitting layer.

[0017] The light-emitting device may further include: a third emitting layer disposed between the second emitting layer and the second electrode; and a second partial transmission mirror disposed between the second emitting layer and the third emitting layer.

[0018] The first and second partial transmission mirrors can be arranged such that a first resonant mode can be formed between the reflective layer and the first partial transmission mirror, a second resonant mode can be formed between the reflective layer and the second partial transmission mirror, and a third resonant mode can be formed between the reflective layer and the second electrode.

[0019] The reflective layer and the second electrode can form a microcavity with a resonant wavelength. The first part of the transmission mirror can be disposed at the first node of the light wave resonating in the microcavity, and the second part of the transmission mirror can be disposed at the second node of the light wave resonating in the microcavity.

[0020] According to one aspect of an exemplary embodiment, a light-emitting device is provided, comprising: a reflective layer; a first electrode on the reflective layer; a second electrode facing the first electrode; a phase correction layer disposed between the first electrode and the second electrode; a first emitting layer disposed between the first electrode and the phase correction layer; a second emitting layer disposed between the phase correction layer and the second electrode; a first partial transmissive mirror disposed between the phase correction layer and the first emitting layer; and a second partial transmissive mirror disposed between the phase correction layer and the second emitting layer, wherein the first partial transmissive mirror and the second partial transmissive mirror are arranged such that a first or higher order resonant mode is formed between the reflective layer and the first partial transmissive mirror, and a second or higher order resonant mode is formed between the reflective layer and the second electrode.

[0021] The first electrode may include a transparent electrode, and the second electrode may include a partially transmissive electrode that reflects some light while transmitting other light.

[0022] The reflective layer and the second electrode can form a microcavity with a resonant wavelength, and the phase correction layer can be located at the node of the light wave resonating within the microcavity.

[0023] The reflective layer, the second electrode, the first partial transmission mirror, and the second partial transmission mirror can cause the light reflected by the reflective layer, the second electrode, the first partial transmission mirror, and the second partial transmission mirror to exhibit phase modulation greater than 180 degrees.

[0024] The phase correction layer may include a transparent conductive material.

[0025] The thickness of the phase correction layer can be from about 5 nm to about 150 nm.

[0026] Each of the first and second transmission mirrors may include silver (Ag), aluminum (Al), a silver alloy, or an aluminum alloy.

[0027] Each of the first and second transmission mirrors has a thickness of approximately 5 nm to approximately 30 nm.

[0028] The optical distance between the reflective layer and the first partial transmissive mirror can be set such that a primary resonant mode or a secondary resonant mode is formed between the reflective layer and the first partial transmissive mirror, and the optical distance between the second partial transmissive mirror and the second electrode can be set such that the primary resonant mode or the secondary resonant mode is formed between the second partial transmissive mirror and the second electrode.

[0029] The first emitting layer may include: a first hole transport layer disposed on the first electrode; a first organic emitting material layer disposed on the first hole transport layer; and a first electron transport layer disposed on the first organic emitting material layer. The second emitting layer may include: a second hole transport layer disposed on the second portion of the transmission mirror; a second organic emitting material layer disposed on the second hole transport layer; and a second electron transport layer disposed on the second organic emitting material layer.

[0030] The first organic emitting material layer and the second organic emitting material layer generate light of the same wavelength.

[0031] The optical distance between the reflective layer and the first partial transmission mirror can be set such that a resonant mode is formed for the wavelength of light generated from the first organic emitting material layer, and the optical distance between the second partial transmission mirror and the second electrode can be set such that a resonant mode is formed for the wavelength of light generated from the second organic emitting material layer.

[0032] The first organic emitting material layer can generate light of a first wavelength, and the second organic emitting material layer can generate light of a second wavelength that is different from the first wavelength.

[0033] The optical distance between the reflective layer and the first partial transmission mirror can be set such that a resonant mode is formed for the first wavelength, and the optical distance between the second partial transmission mirror and the second electrode can be set such that a resonant mode is formed for the second wavelength.

[0034] According to one aspect of an example embodiment, a display device is provided, comprising: a plurality of pixels, wherein each of the plurality of pixels includes: a reflective layer; a first electrode disposed on the reflective layer; a second electrode facing the first electrode; a first emitting layer disposed between the first electrode and the second electrode; a second emitting layer disposed between the first emitting layer and the second electrode; and a partial transmissive mirror disposed between the first emitting layer and the second emitting layer, such that a first or higher order resonant mode is formed between the reflective layer and the partial transmissive mirror, and a second or higher order resonant mode is formed between the reflective layer and the second electrode. Attached Figure Description

[0035] The above and other aspects, features, and advantages of some embodiments of this disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0036] Figure 1 This is a schematic cross-sectional view illustrating the structure of the light-emitting device according to an embodiment;

[0037] Figure 2 It shows Figure 1 A conceptual diagram of the microcavity structure of the light-emitting device shown;

[0038] Figure 3A and Figure 3B It shows Figure 1 An example of the resonant mode of the microcavity of the light-emitting device shown;

[0039] Figure 4 This is a schematic cross-sectional view illustrating the structure of the light-emitting device according to an embodiment;

[0040] Figure 5 This is a schematic cross-sectional view illustrating the structure of the light-emitting device according to an embodiment;

[0041] Figure 6 It shows Figure 5 A conceptual diagram of the microcavity structure of the light-emitting device shown;

[0042] Figures 7A to 7C It shows Figure 5 An example of the resonant mode of the microcavity of the light-emitting device shown;

[0043] Figure 8 It shows a comparison with the comparative example, based on Figure 5 A graph illustrating an example of the change in emission characteristics of the light emitter at the resonant order in the light-emitting device shown.

[0044] Figure 9 It shows a comparison with the comparative example, based on Figure 5 A graph illustrating an example of the change in the light-emitting characteristics of a light-emitting device at a resonant order in the light-emitting device shown.

[0045] Figure 10 This is a schematic cross-sectional view illustrating the structure of the light-emitting device according to an embodiment;

[0046] Figure 11 This is a schematic cross-sectional view illustrating the structure of the light-emitting device according to an embodiment;

[0047] Figures 12A to 12C It shows Figure 11 An example of the resonant mode of the microcavity of the light-emitting device shown;

[0048] Figure 13 The change in the resonant wavelength of the secondary resonator is shown relative to... Figure 11 An example of changing the thickness of the phase correction layer in the light-emitting device shown;

[0049] Figure 14 It shows the comparison with the comparative example regarding Figure 11A graph illustrating an example of the change in emission characteristics of the light emitter at the resonant order in the light-emitting device shown.

[0050] Figure 15 This is a conceptual diagram illustrating the microcavity structure of a light-emitting device according to an example embodiment;

[0051] Figure 16 A schematic cross-sectional view of the structure of the light-emitting device according to an embodiment is shown; and

[0052] Figure 17 This is a schematic cross-sectional view of the structure of a display device according to an embodiment. Detailed Implementation

[0053] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein similar elements are indicated by similar reference numerals throughout the drawings. In this respect, embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, embodiments are described below solely by reference to the accompanying drawings to explain various aspects. The term “and / or” as used herein includes any one and all combinations of one or more of the relevant listed items. Expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list.

[0054] In the following description, a light-emitting device and a display device including the light-emitting device will be described in detail with reference to the accompanying drawings. The same reference numerals always denote the same elements, and the dimensions of the elements may be enlarged in the drawings for clarity and ease of explanation. The embodiments described below are merely examples, and various modifications can be made according to the embodiments.

[0055] In the layered structure described below, the expressions "above" or "on" can include not only "directly on" in a contact manner but also "on" in a non-contact manner. The singular form encompasses the plural form unless there is a clear difference in meaning in the context. It will also be understood that the terms "comprising" and / or "including" as used herein specify the presence of the described feature or element, but do not preclude the presence or addition of one or more other features or elements.

[0056] The use of “the (said)” and other similar indicator words can correspond to both the singular and plural forms. Unless otherwise expressly mentioned or described, the order of operations according to the method of this disclosure may be performed in any appropriate order. This disclosure is not limited to the order of the mentioned operations.

[0057] Terms such as “unit” or “module” used in the embodiments refer to a unit for processing at least one function or operation, and may be implemented in hardware or software, or a combination of hardware and software.

[0058] The connecting lines or connectors shown in the various accompanying figures are intended to illustrate the functional relationships and / or physical or logical couplings between the various components. It should be noted that in actual equipment, there may be many alternative or additional functional relationships, physical connections, or logical connections.

[0059] Any and all examples or language used herein are intended only to better illustrate this disclosure and do not limit the scope of this disclosure unless otherwise required.

[0060] Figure 1 This is a schematic cross-sectional view illustrating the structure of the light-emitting device 200 according to an embodiment. (Reference) Figure 1 The light-emitting device 200 according to an embodiment may include: a reflective layer 110; a first electrode 120 disposed on the reflective layer 110; a second electrode 150 disposed facing the first electrode 120; a partially transmissive mirror 140 disposed between the first electrode 120 and the second electrode 150; a first emitting layer 130a disposed between the first electrode 120 and the partially transmissive mirror 140; and a second emitting layer 130b disposed between the partially transmissive mirror 140 and the second electrode 150. The light-emitting device 200 may further include: a transparent passivation layer 160 disposed on the second electrode 150 to protect the second electrode 150.

[0061] The light-emitting device 200 can be an organic light-emitting device, also known as an organic light-emitting diode (OLED). The first emitting layer 130a and the second emitting layer 130b can be organic emitting layers comprising organic light-emitting materials. For example, the first emitting layer 130a may include: a first hole transport layer 132a disposed on the first electrode 120; a first organic emitting material layer 131a disposed on the first hole transport layer 132a; and a first electron transport layer 133a disposed on the first organic emitting material layer 131a. The second emitting layer 130b may include: a second hole transport layer 132b disposed on the partial transmissive mirror 140; a second organic emitting material layer 131b disposed on the second hole transport layer 132b; and a second electron transport layer 133b disposed on the second organic emitting material layer 131b.

[0062] The first hole transport layer 132a and the second hole transport layer 132b can also function as hole injection layers, and the first electron transport layer 133a and the second electron transport layer 133b can also function as electron injection layers. Separate additional hole injection layers can be provided between the first electrode 120 and the first hole transport layer 132a, and between a portion of the transmission mirror 140 and the second hole transport layer 132b. Separate additional electron injection layers can also be provided between the first electron transport layer 133a and the portion of the transmission mirror 140, and between the second electron transport layer 133b and the second electrode 150. Furthermore, the first emitter layer 130a and the second emitter layer 130b can also include various additional layers as needed. For example, the first emitter layer 130a and the second emitter layer 130b can also include an electron blocking layer, a hole blocking layer, etc.

[0063] In this structure, holes provided by the first hole transport layer 132a and the second hole transport layer 132b, and electrons provided by the first electron transport layer 133a and the second electron transport layer 133b, combine in the first organic emitting material layer 131a and the second organic emitting material layer 131b to generate light. The first organic emitting material layer 131a and the second organic emitting material layer 131b can be formed by doping the organic matrix with a dopant material. The wavelength of the light generated by the first organic emitting material layer 131a and the second organic emitting material layer 131b can be determined based on the properties of the organic matrix and the dopant material.

[0064] The first electrode 120 can be used as an anode to provide holes to the first emitter layer 130a and the second emitter layer 130b, and the second electrode 150 can be used as a cathode to provide electrons to the first emitter layer 130a and the second emitter layer 130b. For this purpose, the first electrode 120 may comprise a material with a relatively high work function, and the second electrode 150 may comprise a material with a relatively low work function.

[0065] Alternatively, the first electrode 120 may be a transparent electrode that transmits light (e.g., visible light). For example, the first electrode 120 may include a transparent conductive oxide, such as at least one of indium tin oxide (ITO), indium zinc oxide (IZO), and zinc aluminum oxide (AZO).

[0066] The second electrode 150 can be a partially transmissive electrode that reflects a portion of the light while transmitting another portion. For this purpose, the second electrode 150 can include a very thin reflective metal. For example, the second electrode 150 can include silver (Ag), aluminum (Al), a silver alloy, or an aluminum alloy. For instance, a silver alloy can include a mixed layer of silver (Ag) and magnesium (Mg), and an aluminum alloy can include a mixed layer of aluminum (Al) and lithium (Li). The total thickness of the second electrode 150 can be from about 5 nm to about 30 nm. Because the second electrode 150 is very thin, a portion of the light can pass through the reflective metal.

[0067] The reflective layer 110 can be configured to reflect light generated by the first emitting layer 130a and the second emitting layer 130b and transmitted through the first electrode 120. For this purpose, the reflective layer 110 may include silver (Ag), gold (Au), aluminum (Al), or alloys thereof. However, this disclosure is not limited thereto, and the reflective layer 110 may include other reflective materials.

[0068] The reflective layer 110 is used to form a microcavity together with the second electrode 150. In other words, a microcavity is formed between the reflective layer 110 and the second electrode 150 of the light-emitting device 200. For example, light generated by the first emitting layer 130a and the second emitting layer 130b can reciprocate and resonate between the reflective layer 110 and the second electrode 150, and then light corresponding to the resonant wavelength of the microcavity can pass through the second electrode 150 and be emitted to the outside.

[0069] The resonant wavelength of the microcavity formed between the reflective layer 110 and the second electrode 150 can be determined by the optical length L of the microcavity. For example, when the resonant wavelength of the microcavity is λ, the optical length of the microcavity can be nλ / 2 (n is a natural number). The optical length L of the microcavity can be determined based on the sum of the optical thicknesses of the layers forming the microcavity between the metallic reflective layer 110 and the second electrode 150, the phase delay caused by the second electrode 150, and the phase delay caused by the reflective layer 110. Here, the thickness of the layers forming the microcavity between the reflective layer 110 and the second electrode 150 is not a simple physical thickness, but a thickness that takes into account the refractive index of the material of the layers forming the microcavity. For example, the optical thickness of the layers forming the microcavity is the sum of the optical thicknesses of all layers between the reflective layer 110 and the second electrode 150.

[0070] To improve the emission efficiency of the light-emitting device 200, the optical length L of the microcavity can be determined such that the resonant wavelength of the microcavity matches the emission wavelength of the first emitting layer 130a and the second emitting layer 130b. In other words, the resonant wavelength λ of the microcavity can be the same as the emission wavelength of the first emitting layer 130a and the second emitting layer 130b. For this purpose, the optical thickness of the layer disposed between the reflective layer 110 and the second electrode 150 can be adjusted by considering the emission wavelengths of the first emitting layer 130a and the second emitting layer 130b. By using such a microcavity, the light-emitting device 200 can emit light along a single linear direction and only within a narrow wavelength band, thus improving the color purity of the light emitted from the light-emitting device 200.

[0071] Meanwhile, in microcavity structures, the radiative attenuation rate of the light source varies under the influence of the microcavity's Q factor and modulus volume; this is known as the Purcell effect. Enhancing the Purcell effect can increase the radiative attenuation rate and spontaneous emission rate of the light source. In organic light-emitting devices, the light source represents the luminescent dopant, and the photoluminescence quantum yield (PLQY) of the dopant is increased through the Purcell effect, thereby further improving the device's emission efficiency. Even if the dopant's PLQY is close to 1, the increased radiative attenuation rate due to the Purcell effect of the microcavity can lead to an increase in the expected lifetime of the light-emitting device.

[0072] Typically, the Purcell effect is strong in the first-order resonant mode when n = 1 (i.e., the optical length L of the microcavity is λ / 2), and weakens rapidly with increasing n and resonant order. This is because as the resonator length increases, the free spectral region decreases, and the density of optical states (ODOS) formed by the microcavity decreases, thereby reducing the efficiency of the light emitter inside the microcavity. Therefore, although microcavities with a first-order resonant mode are most effective for light-emitting devices, higher-order resonant modes can also be used when the thickness of the hole transport layer or emitter layer needs to be increased for the driving stability of the light-emitting device, when multiple emitter layers are used, or when a series structure of multiple stacked light-emitting devices is used.

[0073] According to this embodiment, a partial transmission mirror 140 inside the microcavity is used to enhance the Purcell effect by giving the microcavity, which has a second or higher order resonant mode, a first order resonant mode. For example, Figure 2 It shows Figure 1 A conceptual diagram of the microcavity structure of the light-emitting device 200 is shown. (Reference) Figure 2The microcavity with a second resonant mode is formed by a reflective layer 110 and a second electrode 150. A partial transmission mirror 140 is disposed in the region where the electric field intensity of the light wave resonating within the microcavity is minimal (i.e., at the node of the light wave resonating within the microcavity). Then, a portion of the light incident on the partial transmission mirror 140 is reflected by the partial transmission mirror 140 to form a new, smaller resonator. Therefore, multiple resonant modes can be formed in the microcavity.

[0074] Figure 3A and Figure 3B It shows Figure 1 An example of the resonant mode of the microcavity of the light-emitting device 200 shown. First, refer to... Figure 3A A resonator with a single-mode resonance can be formed by a reflective layer 110 and a portion of a transmission mirror 140. Furthermore, as... Figure 3B As shown, a resonator with a secondary resonance mode can be formed by a reflective layer 110 and a second electrode 150. As described above, a partial transmission mirror 140 is also disposed in the microcavity, so the microcavity can also have a primary resonance mode, thereby increasing ODOS. A primary resonator with a primary resonance mode can also be formed by a partial transmission mirror 140 and a second electrode 150. Therefore, two primary resonators with a primary resonance mode are connected to form a secondary resonator with a secondary resonance mode.

[0075] The partial transmission mirror 140 may comprise the same material as the second electrode 150. In other words, the partial transmission mirror 140 may comprise a reflective and conductive metallic material, such as silver (Ag), aluminum (Al), a silver alloy, or an aluminum alloy. The partial transmission mirror 140 may be formed to have a thin thickness that allows a portion of light to be transmitted. For example, the partial transmission mirror 140 may have a thickness of about 5 nm to about 30 nm. If desired, the thickness of the partial transmission mirror 140 may be selected to be different from the thickness of the second electrode 150 that emits light to the outside of the light-emitting device 200. In other words, the reflectivity of the partial transmission mirror 140 may be selected to be different from the reflectivity of the second electrode 150.

[0076] Furthermore, the first emitting layer 130a, disposed between the reflective layer 110 and the partial transmission mirror 140, can be located in the region where the electric field intensity of the light wave resonating within the microcavity is greatest, i.e., at the antinode of the light wave resonating within the microcavity. The thickness and material of the electron transport layer and the hole transport layer can be selected such that holes and electrons injected from the electrodes can efficiently generate excitons in the emitting layer. Positioning the emitting layer at the antinode of the microcavity may be optically most advantageous. The second emitting layer 130b, disposed between the partial transmission mirror 140 and the second electrode 150, can also be located at the antinode of the light wave resonating within the microcavity.

[0077] Figure 4This is a schematic cross-sectional view illustrating the structure of the light-emitting device 210 according to an embodiment. (Reference) Figure 4 The light-emitting device 210 may further include a transparent conductor layer 141 disposed on the upper surface of the partial transmission mirror 140 facing the second electrode 150. The transparent conductor layer 141 may function similarly to the first electrode 120. The transparent conductor layer 141 disposed between the partial transmission mirror 140 and the second emitting layer 130b may include a material with a high work function to provide holes to the second emitting layer 130b. For example, the transparent conductor layer 141 may include ITO, IZO, AZO, etc.

[0078] In addition, the light-emitting device 210 may also include a charge generation layer 142 disposed between the first emission layer 130a and the second emission layer 130b. The charge generation layer 142 can be used to improve charge transport between the first organic emission material layer 131a and the second organic emission material layer 131b. Figure 4 The diagram shows a charge generation layer 142 disposed between the lower surface of a portion of the transmission mirror 140 and the upper surface of the first emission layer 130a, but it is not limited thereto, and the charge generation layer 142 may be disposed between the first emission layer 130a and the second emission layer 130b.

[0079] The remaining configuration of the light-emitting device 210 can be combined with... Figure 1 The remaining configuration of the light-emitting device 200 shown is the same. Therefore, it will be omitted. Figure 4 A more detailed description of the light-emitting device 210 shown.

[0080] Figure 5 This is a schematic cross-sectional view illustrating the structure of the light-emitting device 220 according to an embodiment. (Reference) Figure 5 The light-emitting device 220 may include: a reflective layer 110; a first transparent electrode 120 disposed on the reflective layer 110; a first emitting layer 130a disposed on the first electrode 120; a first partial transmission mirror 140a disposed on the first emitting layer 130a; a second emitting layer 130b disposed on the first partial transmission mirror 140a; a second partial transmission mirror 140b disposed on the second emitting layer 130b; a third emitting layer 130c disposed on the second partial transmission mirror 140b; and a second electrode 150 disposed on the third emitting layer 130c. Furthermore, the light-emitting device 220 may also include a passivation layer 160 disposed on the second electrode 150.

[0081] and Figure 1 The light-emitting device 200 shown and Figure 4Compared to the light-emitting device 210 shown, the light-emitting device 220 may further include: a third emitting layer 130c disposed between the second emitting layer 130b and the second electrode 150; and a second partial transmissive mirror 140b disposed between the second emitting layer 130b and the third emitting layer 130c. Although Figure 1 The light-emitting device 200 shown and Figure 4 The microcavity of the light-emitting device 210 shown is configured to have a secondary resonant mode, but Figure 5 The microcavity of the light-emitting device 220 shown has a third-order resonant mode. Furthermore, the resonant order of the microcavity is not limited to this, and the microcavity can be configured to have a fourth-order or higher resonant mode.

[0082] Figure 6 It shows Figure 5 A conceptual diagram of the microcavity structure of the light-emitting device 220 shown. (Reference) Figure 6 A microcavity with a third resonant mode is formed between the reflective layer 110 and the second electrode 150. A first partial transmission mirror 140a disposed between the first emitting layer 130a and the second emitting layer 130b can be located in the first node region of the light wave resonating in the microcavity, and a second partial transmission mirror 140b disposed between the second emitting layer 130b and the third emitting layer 130c can be located in the second node region of the light wave resonating in the microcavity. In this case, the first emitting layer 130a can be located in the first antinode region of the light wave resonating in the microcavity, the second emitting layer 130b can be located in the second antinode region of the light wave resonating in the microcavity, and the third emitting layer 130c can be located in the third antinode region of the light wave resonating in the microcavity.

[0083] Figures 7A to 7C It shows Figure 5 An example of the resonant mode of the microcavity of the light-emitting device 220 shown. (Reference) Figures 7A to 7C A primary resonant mode can be formed between the reflective layer 110 and the first partial transmission mirror 140a; a secondary resonant mode can be formed between the reflective layer 110 and the second partial transmission mirror 140b; and a tertiary resonant mode can be formed between the reflective layer 110 and the second electrode 150. These multiple resonant modes can be... Figure 6 The diagram shown is formed by placing the first partial transmission mirror 140a and the second partial transmission mirror 140b in different node regions of the light wave resonating in the microcavity.

[0084] As described above, multiple small resonators can be formed within a large microcavity, and these resonators can be optically interconnected. Optical effects can then be achieved through the interaction of first-order, second-order, and third-order resonances. For example, Figure 8 It shows a comparison with the comparative example, based on Figure 5A graph illustrating an example of the change in emission characteristics of the resonant light emitter in the light-emitting device 220 shown, and Figure 9 It shows a comparison with the comparative example, based on Figure 5 A graph illustrating an example of the change in the light-emitting characteristics of the light-emitting device 220 at the resonant order shown. In other words, Figure 8 The graph shows the intensity of light generated by the light emitter located in the microcavity compared to the comparative example, and Figure 9 The graph shows the intensity of light resonating in the microcavity and emitted to the outside of the light-emitting device 220 through the second electrode 140, compared to the comparative example.

[0085] refer to Figure 8 As can be seen, the intensity of the light generated by the luminescent body decreases as the resonance order increases from the first resonance mode to the second resonance mode and then to the third resonance mode. This can be explained as a result of the Purcell effect described above. Meanwhile, as in this embodiment, it can be seen that when the first partial transmission mirror 140a and the second partial transmission mirror 140b are used to generate additional first and second resonance modes in the microcavity, the emission characteristics of the luminescent body are further improved compared to the case with only a first resonance mode. This can be seen as a result of enhanced characteristics through the constructive interference of various resonance modes. Furthermore, refer to... Figure 9 The intensity of light emitted to the outside of the light-emitting device 220 according to the embodiment is improved by about two times compared with the case of only having a single resonant mode, so it can be predicted that the light extraction efficiency is also improved.

[0086] As described above, partial transmission mirrors 140, 140a, and 140b can be configured to form first-order or higher-order resonant modes between the reflective layer 110 and the partial transmission mirror 140, between the partial transmission mirrors 140a and 140b, and between the reflective layer 110 and the second electrode 150, thereby forming second-order or higher-order resonant modes. Then, even when the microcavity-based light-emitting device includes multiple emitting layers or a thick organic layer to form second-order or higher-order resonant modes, the first-order resonant condition can be satisfied through the partial transmission mirrors inside the microcavity. Therefore, it is expected that the efficiency of the light-emitting device can be further improved, or the driving lifetime of the light-emitting device can be increased due to the enhancement of the Purcell effect.

[0087] Figure 10 This is a schematic cross-sectional view illustrating the structure of the light-emitting device 230 according to an embodiment. (Reference) Figure 10The light-emitting device 230 may further include: a first transparent conductor layer 141a disposed between the upper surface of the first partial transmission mirror 140a and the second emitting layer 130b; and a second transparent conductor layer 141b disposed between the upper surface of the second partial transmission mirror 140b and the third emitting layer 130c. Furthermore, the light-emitting device 230 may also include: a first charge-generating layer 142a disposed between the first emitting layer 130a and the second emitting layer 130b; and a second charge-generating layer 142b disposed between the second emitting layer 130b and the third emitting layer 130c. Figure 10 Other configurations of the light-emitting device 230 shown are similar to Figure 5 The other configurations of the light-emitting device 220 shown are the same, so its detailed description will be omitted.

[0088] Figure 11 This is a schematic cross-sectional view illustrating the structure of the light-emitting device 240 according to an embodiment. (Reference) Figure 11 The light-emitting device 240 may include: a reflective layer 110; a first transparent electrode 120 disposed on the reflective layer 110; a second electrode 150 disposed facing the first electrode 120 and having partial transmissivity; a phase correction layer 144 disposed between the first electrode 120 and the second electrode 150; a first emitting layer 130a disposed between the first electrode 120 and the phase correction layer 144; a second emitting layer 130b disposed between the phase correction layer 144 and the second electrode 150; a first partially transmissive mirror 145 disposed between the phase correction layer 144 and the first emitting layer 130a; and a second partially transmissive mirror 146 disposed between the phase correction layer 144 and the second emitting layer 130b. Furthermore, the light-emitting device 240 may also include a passivation layer 160 disposed on the second electrode 150.

[0089] exist Figures 1 to 10 In this context, it is assumed that the phase of the light reflected by the reflective layer 110, the second electrode 150, and the partial transmission mirrors 140, 140a, and 140b changes by 180 degrees (i.e., π). However, in the case of a metallic mirror, a phase modulation of approximately 1.1 to 1.3 times actually occurs due to the evanescent wave effect. For example, in a silver (Ag) mirror, a phase modulation of 1.3 × 180 degrees occurs. Therefore, the optical length of the primary resonator can actually be shorter than λ / 2. For example, when the resonant wavelength is 450 nm, the actual optical length of the primary resonator is not approximately 225 nm, but approximately 170 nm. The reason for the reduction in resonator length by approximately 55 nm is that the reflection phase modulation of the silver thin film is 1.3π instead of π.

[0090] Such phase modulation greater than π observed in a metallic mirror makes it difficult to connect multiple primary resonators in series. When two primary resonators configured with phase modulation greater than π are connected in series, the resulting resonator is shorter than the length required to satisfy the second-order resonance condition, and the actual resonant wavelength is shorter than the target resonant wavelength. For example, when two primary resonators with a resonant wavelength of 450 nm are connected in series, the second-order resonator can have a resonant wavelength of approximately 420 nm. When three primary resonators configured with phase modulation greater than π are connected in series, the resulting resonator is shorter than the length required to satisfy the third-order resonance condition. Therefore, constructive interference may not occur between various resonant modes that satisfy the resonance conditions of multiple resonators.

[0091] Figure 11 The light-emitting device 240 shown may therefore also include an additional cavity for correcting the phase in the microcavity, so that the length of the second-order or higher-order resonators remains unchanged. The phase correction layer 144 can serve as such an additional cavity, correcting the phase without directly contributing to light emission. The phase correction layer 144 can be connected in series with first-order resonators disposed on both sides of the phase correction layer 144, and the resonant wavelength of the final second-order or higher-order resonators is matched with the target resonant wavelength. In other words, the resonant wavelength of the final second-order or higher-order resonators can be determined based on the thickness of the phase correction layer 144. The accurate thickness of the phase correction layer 144 that matches the resonant wavelength of the final second-order or higher-order resonators with the target resonant wavelength can be calculated using, for example, a finite-difference time-domain simulator.

[0092] Figures 12A to 12C It shows Figure 11 An example of the resonant mode of the microcavity of the light-emitting device 240 shown. (Reference) Figure 12A The primary resonator is formed by a reflective layer 110 and a first portion of a transmission mirror 145. Furthermore, reference... Figure 12B Another primary resonator is formed by a second portion of the transmission mirror 146 and a second electrode 150. Furthermore, refer to... Figure 12C A secondary resonator is formed between a reflective layer 110 and a second electrode 150, which connects two primary resonators. A phase correction layer 144 is disposed between a first partial transmission mirror 145 and a second partial transmission mirror 146 to ensure that the resonant wavelength of the secondary resonator remains constant. The phase correction layer 144 may be located in a microcavity between the reflective layer 110 and the second electrode 150 or at a node of the light wave resonating in the secondary resonator. The first partial transmission mirror 145 and the second partial transmission mirror 146 may be configured to directly contact the two surfaces of the phase correction layer 144.

[0093] The reflective layer 110, the second electrode 150, the first partial transmission mirror 145, and the second partial transmission mirror 146 can result in a phase modulation of greater than 180 degrees with respect to the reflected light. The thickness D of the phase correction layer 144 can be determined taking into account this phase modulation of greater than 180 degrees. Specifically, the thickness D of the phase correction layer 144 can be determined to match the resonant wavelengths of the two primary resonators with the resonant wavelength of the secondary resonator. For example, the thickness D of the phase correction layer 144 can be determined in the range of about 5 nm to about 150 nm. The phase correction layer 144 may comprise a transparent conductive material with a high refractive index.

[0094] Figure 13 The change in the resonant wavelength of the secondary resonator is shown relative to... Figure 11 This is an example of changing the thickness of the phase correction layer 144 in the light-emitting device 240 shown. Two primary resonators are designed to have a resonant wavelength of approximately 450 nm. The reflective layer 110 includes a silver film with a thickness of approximately 200 nm, each of the first partial transmission mirror 145 and the second partial transmission mirror 146 has a thickness of approximately 10 nm, and the second electrode 150 has a thickness of approximately 20 nm. The distance between the reflective layer 110 and the first partial transmission mirror 145, and the distance between the second partial transmission mirror 146 and the second electrode 150, are both fixed at approximately 168 nm. (That is, changing the thickness of the phase correction layer 144 from approximately 10 nm to approximately 150 nm) while simultaneously calculating the resonant characteristics of the secondary resonators at the changed phase correction distance. Reference Figure 13 As can be seen, when the thickness of the phase correction layer 144 is about 10 nm, the resonant wavelength is formed at about 410 nm. As the thickness of the phase correction layer 144 increases, the resonant wavelength gradually increases, and when the thickness of the phase correction layer 144 is about 90 nm, a resonant wavelength of about 450 nm is formed.

[0095] Figure 14 It shows the comparison with the comparative example regarding Figure 11 A graph illustrating an example of the change in emission characteristics of the light-emitting element at the resonant order in the light-emitting device 240 shown. Figure 14 The graph shows the intensity of light generated by a light emitter positioned in a microcavity, compared to a comparative example. (Reference) Figure 14As can be seen, the intensity of the light generated by the light emitter decreases as the resonance order increases from the first resonance mode to the second resonance mode and then to the third resonance mode. Simultaneously, it can be seen that the emission characteristics of the light emitter according to the embodiment are further improved compared to the case with only a first resonance mode. As described above, considering the phase delay caused by the metals constituting the reflective layer 110, the second electrode 150, the first partial transmission mirror 145, and the second partial transmission mirror 146, and therefore a phase correction layer 144 is provided, even when the phase delay in the reflective layer 110, the second electrode 150, the first partial transmission mirror 145, and the second partial transmission mirror 146 is greater than 180 degrees, all first or higher order resonance conditions are satisfied, thereby improving the emission efficiency of the light-emitting device 240.

[0096] exist Figures 12A to 12C The previous description depicted a final microcavity with a secondary resonant mode achieved by connecting two primary resonators. However, this disclosure is not intended to be limited to this. For example, Figure 15 This is a conceptual diagram illustrating the microcavity structure of a light-emitting device according to an example embodiment. (Reference) Figure 15 The resonator formed between the reflective layer 110 and the first partial transmission mirror 145 is a secondary resonator with a second resonance mode. Furthermore, the resonator formed between the second partial transmission mirror 146 and the second electrode 150 is also a secondary resonator with a second resonance mode. Therefore, the resonator formed between the reflective layer 110 and the second electrode 150 is a fourth resonator with a fourth resonance mode. In this case, the phase correction layer 144 can be located at the second node of the light wave resonating in the fourth resonator.

[0097] As described above, a first partial transmission mirror 145 and a second partial transmission mirror 146 can be provided to form a first or higher order resonant mode between the reflective layer 110 and the first partial transmission mirror 145, and a second or higher order resonant mode between the reflective layer 110 and the second electrode 150. Furthermore, a phase correction layer 144 of a specific thickness can be provided between the first partial transmission mirror 145 and the second partial transmission mirror 146 for phase correction. Additionally, as... Figure 15 As shown, the optical distance L1 between the reflective layer 110 and the first partial transmission mirror 145 can be selected to form a primary resonance mode or a secondary resonance mode between the reflective layer 110 and the first partial transmission mirror 145. The optical distance L2 between the second partial transmission mirror 146 and the second electrode 150 can also be selected to form a primary resonance mode or a secondary resonance mode between the second partial transmission mirror 146 and the second electrode 150.

[0098] Meanwhile, the first emission layer 130a and the second emission layer 130b can have the same characteristics as the previous reference. Figure 1The first emitter layer 130a and the second emitter layer 130b described have the same configuration. For example, the first emitter layer 130a may include: a first hole transport layer disposed on the first electrode 120; a first organic emitter material layer disposed on the first hole transport layer; and a first electron transport layer disposed on the first organic emitter material layer. Furthermore, the second emitter layer 130b may include: a second hole transport layer disposed on the second partial transmission mirror 146; a second organic emitter material layer disposed on the second hole transport layer; and a second electron transport layer disposed on the second organic emitter material layer.

[0099] The first organic emitting material layer in the first emitting layer 130a and the second organic emitting material layer in the second emitting layer 130b can both include organic materials that generate light with the same wavelength. The optical distance L1 between the reflective layer 110 and the first partial transmission mirror 145 and the optical distance L2 between the second partial transmission mirror 146 and the second electrode 150 can be the same and can be selected such that the wavelengths of the light generated in the first and second organic emitting material layers form a resonant mode.

[0100] In the example, the first organic emitting material layer in the first emitting layer 130a may include an organic material that generates light of a first wavelength, and the second organic emitting material layer in the second emitting layer 130b may include an organic material that generates light of a second wavelength different from the first wavelength. In this case, the optical distance L1 between the reflective layer 110 and the first partial transmission mirror 145 can be selected to form a resonant mode for the first wavelength, and the optical distance L2 between the second partial transmission mirror 146 and the second electrode 150 can be selected to form a resonant mode for the second wavelength. Furthermore, the optical distance L between the reflective layer 110 and the second electrode 150 can be selected by adjusting the thickness of the phase correction layer 144 to have a resonant mode for either the first or second wavelength. Alternatively, the thickness of the phase correction layer 144 can be adjusted to have a resonant mode relative to a third wavelength different from the first and second wavelengths. In this case, the light-emitting device 240 can emit multi-color light.

[0101] Although Figure 11 Only two emitting layers are shown, but the first transmitting mirror, phase correction layer, second transmitting mirror, and emitting layer can also be disposed between the second emitting layer 130b and the second electrode 150. In this case, the three emitting layers can generate light of different wavelengths. Alternatively, the three emitting layers can generate light of the same wavelength.

[0102] Figure 16 This is a schematic cross-sectional view illustrating the structure of the light-emitting device 250 according to an embodiment. (Reference) Figure 16The light-emitting device 250 may further include a transparent conductor layer 141 disposed between the upper surface of the second portion of the transmissive mirror 146 and the second emitting layer 130b. Furthermore, the light-emitting device 250 may also include a charge-generating layer 142 disposed between the first emitting layer 130a and the second emitting layer 130b. Figure 16 Other configurations of the light-emitting device 250 shown are similar to Figure 11 The other configurations of the light-emitting device 240 shown are the same, so its detailed description will be omitted.

[0103] The aforementioned light-emitting devices can be applied to multiple pixels of a display device. Figure 17 This is a schematic cross-sectional view illustrating the structure of a display device 1000 according to an embodiment. (Reference) Figure 17 The display device 1000 may include a plurality of pixels that emit light of different colors. Here, the plurality of pixels may include a red pixel 1100, a green pixel 1200, and a blue pixel 1300 disposed adjacent to each other on the same plane of the substrate 1001. Figure 17 For convenience, only one unit pixel including red pixel 1100, green pixel 1200 and blue pixel 1300 is shown. However, in reality, a large number of red pixels 1100, green pixels 1200 and blue pixels 1300 can be repeatedly arranged on the substrate 1001.

[0104] The red pixel 1100 may include: a reflective layer 110 disposed on a substrate 1001; a first electrode 120 disposed on the reflective layer 110; a second electrode 150 disposed facing the first electrode 120; a partially transmissive mirror 140 disposed between the first electrode 120 and the second electrode 150; a first red emitting layer 130Ra disposed between the first electrode 120 and the partially transmissive mirror 140; a second red emitting layer 130Rb disposed between the partially transmissive mirror 140 and the second electrode 150; and a passivation layer 160 disposed on the second electrode 150. The optical distance between the first electrode 120 and the partially transmissive mirror 140 and the optical distance between the partially transmissive mirror 140 and the second electrode 150 are determined to have a first or higher order resonant mode for red light, while the optical distance between the first electrode 120 and the second electrode 150 is determined to have a second or higher order resonant mode for red light.

[0105] Green pixel 1200 and blue pixel 1300 have a structure similar to that of red pixel 1100. Green pixel 1200 includes a first green emitting layer 130Ga and a second green emitting layer 130Gb instead of red emitting layers 130Ra and 130Rb, and blue pixel 1300 includes a first blue emitting layer 130Ba and a second blue emitting layer 130Bb instead of red emitting layers 130Ra and 130Rb. In green pixel 1200, the optical distance between the first electrode 120 and the partial transmissive mirror 140, and the optical distance between the partial transmissive mirror 140 and the second electrode 150, are determined to have a first or higher order resonant mode for green light, while the optical distance between the first electrode 120 and the second electrode 150 is determined to have a second or higher order resonant mode for green light. Furthermore, in the blue pixel 1300, the optical distance between the first electrode 120 and the partial transmissive mirror 140, and the optical distance between the partial transmissive mirror 140 and the second electrode 150 are determined to have a first or higher order resonant mode for blue light, while the optical distance between the first electrode 120 and the second electrode 150 is determined to have a second or higher order resonant mode for blue light.

[0106] exist Figure 17 In the diagram, red pixel 1100, green pixel 1200, and blue pixel 1300 are shown as having the same characteristics as... Figure 1 The light-emitting device 200 shown has the same structure, but is not limited thereto. The display device 1000 can not only... Figure 1 The light-emitting device 200 shown may also be used in accordance with other embodiments of the light-emitting devices 210, 220, 230, 240 and 250, for the red pixel 1100, green pixel 1200 and blue pixel 1300.

[0107] The aforementioned light-emitting devices and display devices can be applied without restriction to devices of various sizes and for various purposes. For example, they can be applied to display panels of mobile phones or smartphones, display panels of tablet computers or smart tablets, display panels of laptops, televisions or smart TVs, or small display panels used in head-mounted displays, eyeglass displays, and goggle-type displays.

[0108] The aforementioned light-emitting devices and display devices can be applied without restriction to devices of various sizes and for various purposes. For example, they can be applied to display panels of mobile phones or smartphones, display panels of tablet computers or smart tablets, display panels of laptops, televisions or smart TVs, or small display panels used in head-mounted displays, eyeglass displays, and goggle-type displays.

[0109] It should be understood that the embodiments described herein should be considered in a descriptive sense and not for limiting purposes only. The description of features or aspects in each embodiment should generally be considered as other similar features or aspects that may be used in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope defined by the appended claims.

Claims

1. A light-emitting device, comprising: Reflective layer; The first electrode is disposed on the reflective layer; The second electrode faces the first electrode; A first emission layer is disposed between the first electrode and the second electrode; A second emission layer is disposed between the first emission layer and the second electrode; A first part of the transmission mirror is disposed between the first emission layer and the second emission layer, such that a first or higher order resonance mode is formed between the reflection layer and the first part of the transmission mirror, and a second or higher order resonance mode is formed between the reflection layer and the second electrode. A transparent conductor layer is located between the upper surface of the first portion of the transmission mirror and the lower surface of the second emission layer; as well as A charge generation layer is located between the upper surface of the first emission layer and the lower surface of the first portion of the transmission mirror. The reflective layer and the second electrode constitute a microcavity with a resonant wavelength. The first part of the transmission mirror is disposed at the node of the light wave resonating in the microcavity.

2. The light-emitting device according to claim 1, wherein The first electrode includes a transparent electrode, and the second electrode includes a partially transmissive electrode that reflects a portion of light while transmitting another portion of light.

3. The light emitting device of claim 1, wherein, The first part of the transmission mirror includes silver (Ag), aluminum (Al), silver alloy, or aluminum alloy.

4. The light-emitting device according to claim 3, wherein The thickness of the first part of the transmission mirror is 5nm to 30nm.

5. The light emitting device of claim 4, wherein, The thickness of the second electrode is different from the thickness of the first part of the transmission mirror.

6. The light-emitting device according to claim 1, wherein The first emission layer includes: A first hole transport layer is disposed on the first electrode; A first organic emission material layer is disposed on the first hole transport layer; and A first electron transport layer is disposed on the first organic emission material layer, and The second emission layer includes: The second hole transport layer is disposed on the first part of the transmissive mirror; A second organic emission material layer is disposed on the second hole transport layer; and The second electron transport layer is disposed on the second organic emission material layer.

7. The light-emitting device according to claim 1, further comprising: A third emission layer is disposed between the second emission layer and the second electrode; as well as The second transmission mirror is disposed between the second emission layer and the third emission layer.

8. The light-emitting device according to claim 7, wherein The first and second partial transmission mirrors are arranged such that a first resonant mode is formed between the reflective layer and the first partial transmission mirror, a second resonant mode is formed between the reflective layer and the second partial transmission mirror, and a third resonant mode is formed between the reflective layer and the second electrode.

9. The light-emitting device according to claim 8, in, The second part of the transmission mirror is positioned at another node of the light wave resonating in the microcavity.

10. A light-emitting device, comprising: Reflective layer; The first electrode is located on the reflective layer; The second electrode faces the first electrode; A phase correction layer is disposed between the first electrode and the second electrode; A first emission layer is disposed between the first electrode and the phase correction layer; A second emission layer is disposed between the phase correction layer and the second electrode; The first transmission mirror is disposed between the phase correction layer and the first emission layer; as well as The second transmission mirror is disposed between the phase correction layer and the second emission layer. The first and second portion of the transmission mirrors are arranged such that a first-order or higher-order resonant mode is formed between the reflective layer and the first portion of the transmission mirror, and a second-order or higher-order resonant mode is formed between the reflective layer and the second electrode. The reflective layer and the second electrode constitute a microcavity with a resonant wavelength. The phase correction layer is located at the node of the light wave resonating within the microcavity.

11. The light-emitting device according to claim 10, wherein, The first electrode includes a transparent electrode, and the second electrode includes a partially transmissive electrode that reflects a portion of light while transmitting another portion of light.

12. The light-emitting device according to claim 10, wherein, The reflective layer, the second electrode, the first partial transmission mirror, and the second partial transmission mirror cause the light reflected from the reflective layer, the second electrode, the first partial transmission mirror, and the second partial transmission mirror to exhibit phase modulation greater than 180 degrees.

13. The light-emitting device according to claim 10, wherein, The phase correction layer comprises a transparent conductive material.

14. The light-emitting device according to claim 13, wherein, The thickness of the phase correction layer is 5 nm to 150 nm.

15. The light-emitting device according to claim 10, wherein, Each of the first and second transmission mirrors comprises silver (Ag), aluminum (Al), a silver alloy, or an aluminum alloy.

16. The light-emitting device according to claim 15, wherein, Each of the first and second transmission mirrors has a thickness of 5 nm to 30 nm.

17. The light-emitting device according to claim 10, wherein, The optical distance between the reflective layer and the first portion of the transmission mirror is set such that a primary or secondary resonant mode is formed between the reflective layer and the first portion of the transmission mirror. The optical distance between the second part of the transmission mirror and the second electrode is set such that the first resonance mode or the second resonance mode is formed between the second part of the transmission mirror and the second electrode.

18. The light-emitting device according to claim 10, in, The first emission layer includes: A first hole transport layer is disposed on the first electrode; A first organic emission material layer is disposed on the first hole transport layer; and A first electron transport layer is disposed on the first organic emission material layer, and The second emission layer includes: The second hole transport layer is disposed on the second part of the transmissive mirror; A second organic emission material layer is disposed on the second hole transport layer; and The second electron transport layer is disposed on the second organic emission material layer.

19. The light-emitting device according to claim 18, wherein, The first organic emitting material layer and the second organic emitting material layer generate light of the same wavelength.

20. The light-emitting device according to claim 19, wherein, The optical distance between the reflective layer and the first portion of the transmission mirror is set such that a resonant mode is formed for the wavelength of light generated from the first organic emitting material layer, and The optical distance between the second portion of the transmission mirror and the second electrode is set such that a resonant mode is formed for the wavelength of light generated from the second organic emitting material layer.

21. The light-emitting device according to claim 18, wherein, The first organic emitting material layer generates light of a first wavelength, and The second organic emitting material layer generates light of a second wavelength that is different from the first wavelength.

22. The light-emitting device according to claim 21, wherein, The optical distance between the reflective layer and the first portion of the transmission mirror is set such that a resonant mode is formed for the first wavelength, and The optical distance between the second part of the transmission mirror and the second electrode is set to form a resonant mode for the second wavelength.

23. A display device, comprising: Multiple pixels; Each of the plurality of pixels includes: Reflective layer; The first electrode is disposed on the reflective layer; The second electrode faces the first electrode; A first emission layer is disposed between the first electrode and the second electrode; A second emission layer is disposed between the first emission layer and the second electrode; A partial transmissive mirror is disposed between the first emitting layer and the second emitting layer, such that a first or higher order resonant mode is formed between the reflective layer and the partial transmissive mirror, and a second or higher order resonant mode is formed between the reflective layer and the second electrode. A transparent conductor layer is located between the upper surface of the partial transmission mirror and the lower surface of the second emission layer; and A charge generation layer is located between the upper surface of the first emission layer and the lower surface of the partial transmission mirror. The reflective layer and the second electrode constitute a microcavity with a resonant wavelength. The transmission mirror is located at the node of the light wave resonating within the microcavity.

Images