Organic light emitting unit, display apparatus, electronic apparatus, in-vehicle display, and vehicle

Abstract

The invention discloses an organic light emitting unit, a display apparatus, an electronic apparatus, a vehicle-mounted display, and a vehicle. The organic light emitting unit includes a light emitting mechanism having a light emitting layer and an interference reflector between an anode and a cathode facing each other. The interference reflector is disposed in contact with the anode. The interference reflector includes a p-type low refractive index layer as a first charge generation layer having a first type of conductivity and a first refractive index, and an n-type high refractive index layer as a second charge generation layer having a second type of conductivity and a second refractive index. In the interference reflector, p-type low refractive index layers and n-type high refractive index layers are alternately stacked with each other.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Japanese Patent Application No. 2024-185289, filed on October 21, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This application relates to organic light-emitting units, display devices, electronic devices, automotive displays, and vehicles. Background Technology

[0004] It is known that some organic light-emitting units made of organic light-emitting materials are designed to have improved luminous efficiency and enhanced monochromaticity by utilizing the microcavity effect. Figure 30A The element structure of the organic light-emitting unit 501 is shown. This element structure includes an anode 511 and a cathode 512 opposite to each other on a circuit board 510, which form a microcavity. In the case that the anode 511 is a reflective electrode made of metal and the cathode 512 is a semi-transparent electrode, the emission intensity varies according to the distance DA between the center of the anode 511 and the center of the light-emitting layer 513 and the distance DB between the center of the cathode 512 and the center of the light-emitting layer 513. Figure 30B Regions Z01, Z02, and Z03, revealed by optical simulation, are shown, where distances DA and DB provide enhanced microcavity effects. Figure 30B Optical simulation results are shown for a dominant wavelength of 460 nm. Simulation results reflecting the microcavity effect alone show that the emission intensity has the highest first peak in region Z01, and a second highest peak that is almost equal to that in regions Z02 and Z03. In contrast, Figure 31 The experimental results shown indicate that the emission intensity has a peak in region Z01 represented by curve CU11, a peak in region Z02 represented by curve CU12, and a peak in region Z03 represented by curve CU13.

[0005] Specifically, Figure 31 The results show that the peak emission intensity represented by curve CU12 is higher than that represented by curve CU11. Similarly, the peak emission intensity represented by curve CU13 is higher than that represented by curve CU12. These experimental results are inconsistent with simulation results that solely reflect the microcavity effect.

[0006] The optical simulation of the organic light-emitting unit 501, including the reflective metal electrode made of a metal such as silver (Ag) as the anode 511, must take into account optical losses known as surface plasmon oscillator losses. When for Figure 30BThe optical simulation results shown not only reflect the microcavity effect but also, with optical loss, the peak emission intensity in region Z03 is higher than that in region Z02. Furthermore, the peak emission intensity in region Z02 is higher than that in region Z01. These optical simulation results are consistent with... Figure 31 The experimental results shown are consistent.

[0007] Surface plasmon oscillators are electronic oscillations propagating along the surface of a conductor. The organic light-emitting unit 501, including the metal electrode serving as the anode 511, is susceptible to optical losses caused by the coupling of light emitted from the emitting dipole due to molecular excitons in the light-emitting layer with electronic oscillations in the reflecting electrode. Typically, the external quantum efficiency can be calculated by multiplying carrier balance, exciton generation rate, radiation quantum efficiency, and light extraction efficiency in optical simulations. If the radiation quantum efficiency is based on the Purcell factor, the calculations in the optical simulations can reflect the optical losses.

[0008] Top-emitting organic light-emitting diode (OLED) displays all include an organic light-emitting unit 501, which is designed to extract light from one side adjacent to the cathode 512. Top-emitting OLED displays have an extended distance DA from the anode 511 to the center of the light-emitting layer 513 to reduce optical losses. Some top-emitting OLED displays have features such as... Figure 32 The diagram illustrates a series structure of multiple light-emitting layers, such as the two light-emitting layers 513A and 513B, to improve brightness and extend lifetime. However, this series structure, with the same total film thickness as the monolithic structure, has a shorter distance between the lower light-emitting layer 513A and the anode 511, which serves as the reflective electrode. Therefore, in the case of green or blue light, this series structure cannot achieve twice the luminous efficiency of the monolithic structure. An alternative structure is needed for the reflective electrode used as the anode 511 to improve luminous efficiency.

[0009] Unexamined Japanese Patent Application Publication No. 2007-317591 discloses a dielectric mirror that acts as an optical resonator, enhancing light of a specific wavelength. Unexamined Japanese Patent Application Publication No. 2023-4940 discloses a light-emitting device comprising a light-emitting layer containing an organic compound and a low-refractive-index layer. U.S. Patent Application Publication No. 2015 / 0041768 discloses an optical component fabricated by repeatedly and alternately stacking high-refractive-index and low-refractive-index layers on top of each other.

[0010] The structures disclosed in unexamined Japanese Patent Application Publication No. 2007-317591 and US Patent Application Publication No. 2015 / 0041768 both include a reflective mechanism located below the transparent anode and a transparent conductive film with relatively high sheet resistance, which may adversely affect display performance. Structures with increased film thickness to reduce the resistance of the electrodes in the transparent conductive film result in the absorption of a large amount of short-wavelength light, which may impair the luminous efficiency of blue light. The technology disclosed in unexamined Japanese Patent Application Publication No. 2023-4940 aims to enhance monochromaticity through interference. However, this technology requires the stacking of multiple charge transport layers to increase the reflectivity, thus inevitably increasing the driving voltage. Therefore, this technology may encounter challenges in adjusting carrier balance due to insufficient carrier wave.

[0011] In view of the above, the purpose of this disclosure is to provide an organic light-emitting unit, display device, electronic device, vehicle display, and vehicle including the vehicle display that can achieve improved luminous efficiency. Summary of the Invention

[0012] The organic light-emitting unit according to a first aspect of this disclosure includes: a first electrode and a second electrode facing each other; and an organic compound layer disposed between the first electrode and the second electrode, and including at least a light-emitting layer and an interference reflector. The interference reflector includes a first charge-generating layer having a first type of conductivity and a first refractive index, and a second charge-generating layer having a second type of conductivity and a second refractive index, the first charge-generating layer and the second charge-generating layer being alternately stacked. The interference reflector is configured to contact either the first electrode or the second electrode.

[0013] The display device according to the second aspect of this disclosure includes the organic light-emitting unit according to the first aspect.

[0014] The vehicle-mounted display according to the third aspect of this disclosure includes the display device according to the second aspect.

[0015] The electronic device according to the fourth aspect of this disclosure includes the display device according to the second aspect.

[0016] The vehicle according to the fifth aspect of this disclosure includes the vehicle-mounted display according to the third aspect.

[0017] It should be understood that the foregoing general description and the following detailed description are exemplary and illustrative, and do not limit this disclosure.

[0018] This disclosure can provide an organic light-emitting unit, display device, electronic device, vehicle display, and vehicle including the vehicle display that can achieve improved luminous efficiency. Attached Figure Description

[0019] This application can be more fully understood when the following detailed description is considered in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is a schematic diagram showing a first exemplary structure of the organic light-emitting unit according to Embodiment 1;

[0021] Figure 2 This is a graph illustrating an exemplary simulation of the reflectance factor;

[0022] Figure 3 This is a graph illustrating an exemplary simulation of the reflectance factor;

[0023] Figure 4 This is a graph illustrating an exemplary simulation of the reflectance factor;

[0024] Figure 5 This is a cross-sectional view of the light-emitting unit and the driving TFT;

[0025] Figure 6A This is a circuit diagram showing the first pixel circuit;

[0026] Figure 6B This is a circuit diagram showing the second pixel circuit;

[0027] Figure 7 A bar chart is shown to compare optical loss and luminous efficiency;

[0028] Figure 8A This is a schematic diagram illustrating an exemplary structure of a light extraction layer provided with a polarizing plate;

[0029] Figure 8B This is a schematic diagram showing an exemplary structure of a light extraction layer provided with a color filter;

[0030] Figure 9 This is a schematic diagram illustrating an exemplary structure of a microlens array;

[0031] Figure 10 A bar chart is shown for comparing the percentage of loss;

[0032] Figure 11 A graph comparing the current-voltage characteristics between organic material layers is shown.

[0033] Figure 12 The energy states of each layer of the organic light-emitting unit are shown;

[0034] Figure 13 It is a line graph showing the relationship between driving voltage and the concentration of n-type dopant material;

[0035] Figure 14It is a line graph showing the relationship between driving voltage and concentration of p-type dopant material;

[0036] Figure 15 This is a schematic diagram showing a second exemplary structure of the organic light-emitting unit according to Embodiment 1;

[0037] Figure 16 This is a schematic diagram illustrating a third exemplary structure of the organic light-emitting unit according to Embodiment 1;

[0038] Figure 17 A bar chart is shown for comparing the percentage of loss;

[0039] Figure 18A An exemplary comparison structure according to the prior art is shown;

[0040] Figure 18B An exemplary comparison structure according to an embodiment of the present disclosure is shown;

[0041] Figure 19A An exemplary structure of a sub-pixel corresponding to the disclosed technical features is shown;

[0042] Figure 19B An exemplary structure of a sub-pixel corresponding to an embodiment of this disclosure is shown;

[0043] Figure 20 This is a schematic diagram showing an exemplary structure of the organic light-emitting unit according to Embodiment 2;

[0044] Figure 21 This is a schematic diagram showing an exemplary structure of the organic light-emitting unit according to Embodiment 3;

[0045] Figure 22 It is a graph showing the parameters including the reflectance factor in the organic light-emitting unit;

[0046] Figure 23 A bar chart is shown for comparing the percentage of loss;

[0047] Figure 24 This is a cross-sectional view of the light-emitting unit and the driving TFT;

[0048] Figure 25 This is a schematic diagram illustrating an exemplary structure of a display device according to Embodiment 4;

[0049] Figure 26 It is a plan view of a portion of the display area of ​​a display device;

[0050] Figure 27 This is a schematic diagram showing an exemplary structure of an in-vehicle display according to embodiment 5 and a vehicle including the in-vehicle display;

[0051] Figure 28 This is a perspective view of an exemplary structure of a smartphone as an electronic device according to Embodiment 6;

[0052] Figure 29A This is a cross-sectional view of the first sealing structure;

[0053] Figure 29B This is a cross-sectional view of the second sealing structure;

[0054] Figure 29C This is a cross-sectional view of the third sealing structure;

[0055] Figure 30A This is a schematic diagram illustrating an exemplary structure of an organic light-emitting unit in the prior art;

[0056] Figure 30B The emission intensity revealed by optical simulation in the prior art is shown;

[0057] Figure 31 It shows a graph illustrating the emission intensity based on experimental results from the prior art; and

[0058] Figure 32 This is a schematic diagram illustrating an exemplary series structure in another prior art. Detailed Implementation

[0059] Example 1

[0060] Figure 1 This is a schematic diagram illustrating a first exemplary structure of an organic light-emitting unit 1 according to an embodiment. The organic light-emitting unit 1 is a top-emitting OLED. The organic light-emitting unit 1 includes an anode 11 and a cathode 12 opposite to each other on a circuit board 10. The organic light-emitting unit 1 also includes a light-emitting mechanism 20 and an interference reflector 30 disposed between the anode 11 and the cathode 12. The organic light-emitting unit 1 also includes a capping layer 13 on the cathode 12. A layered product made of organic compounds and held between the anode 11 and the cathode 12 is also referred to as an organic compound layer or an organic material layer. The materials of the individual layers do not limit the scope of this disclosure.

[0061] Circuit board 10 is provided with, for example, Figure 6A The pixel circuit PX01 shown is or as Figure 6B The pixel circuit PX02 shown is on a non-flexible or flexible substrate. The circuit board 10 includes a thin-film transistor (TFT) array. The organic light-emitting unit 1 has a multilayer structure on the circuit board 10. The following describes... Figure 1 Assume that circuit board 10 is adjacent to the bottom and far from the top.

[0062] The anode 11 is the lower electrode used as the first electrode in the organic light-emitting unit 1. The anode 11 is connected to a power source (not shown). The anode 11 can be any electrode made of a material that is both transparent and conductive. For example, the anode 11 can be made of indium tin oxide (ITO), tin dioxide (SnO2), or indium zinc oxide (IZO). The organic light-emitting unit 1 according to this embodiment does not require metallic reflection from the anode 11. The anode 11 can be an existing metal electrode, provided that the interference reflector 30 has sufficient reflective properties.

[0063] Cathode 12 is the upper electrode used as the second electrode in organic light-emitting unit 1. Cathode 12 is connected to a power source (not shown). Cathode 12 can be any electrode made of a translucent and semi-reflective material. For example, cathode 12 can be made of aluminum, magnesium-silver alloy, ITO, or IZO.

[0064] The light-emitting mechanism 20, starting from the bottom, sequentially includes a hole injection layer 21, a hole transport layer 22, an electron blocking layer 23, a light-emitting layer 24, a hole blocking layer 25, an electron transport layer 26, and an electron injection layer 27. The light-emitting mechanism 20 can utilize existing OLED device structures and materials, or it can utilize new structures and materials applicable to general OLED devices. The light-emitting mechanism 20 can exclude all or some of the hole injection layer 21, hole transport layer 22, electron blocking layer 23, hole blocking layer 25, electron transport layer 26, and electron injection layer 27. In other words, the light-emitting mechanism 20 includes at least a light-emitting layer 24.

[0065] Hole injection layer 21 facilitates hole injection by lowering the hole injection barrier from anode 11. In hole injection layer 21, the energy level of the highest occupied molecular orbital (HOMO) (referred to as the HOMO level) is lower than the work function of anode 11 but higher than the HOMO level of hole transport layer 22. Therefore, hole injection layer 21 has a HOMO level between the work function of anode 11 and the HOMO level of hole transport layer 22.

[0066] Hole transport layer 22 facilitates the transport of holes to luminescent layer 24. Typically, hole transport layer 22 has a larger band gap than luminescent layer 24. Band gap refers to the energy difference between the HOMO level and the lowest unoccupied molecular orbital (LUMO) level (referred to as the LUMO level).

[0067] Electron blocking layer 23 inhibits electron movement. Electron blocking layer 23 prevents holes from accumulating at the interface between hole transport layer 22 and electron blocking layer 23, and at the interface between electron blocking layer 23 and light-emitting layer 24.

[0068] The light-emitting layer 24 emits light due to the recombination of holes and electrons. Holes are injected into the light-emitting layer 24 from the anode 11. Electrons are injected into the light-emitting layer 24 from the cathode 12. The light-emitting layer 24 is any layer made of fluorescent material, thermally activated delayed fluorescence material, phosphorescent material, or any other organic light-emitting material.

[0069] Hole blocking layer 25 inhibits the movement of holes. Hole blocking layer 25 prevents electrons from accumulating at the interface between light-emitting layer 24 and hole blocking layer 25, and at the interface between hole blocking layer 25 and electron transport layer 26.

[0070] Electron transport layer 26 facilitates the transport of electrons to the light-emitting layer 24. Similar to hole transport layer 22, electron transport layer 26 preferably has a larger band gap than the light-emitting layer 24. Electron transport layer 26 can suppress the movement of excitons generated in the light-emitting layer 24.

[0071] Electron injection layer 27 facilitates electron injection by lowering the electron injection barrier from cathode 12. In electron injection layer 27, the LUMO energy level is higher than the work function of cathode 12 but lower than the LUMO energy level of electron transport layer 26. That is, electron injection layer 27 has a LUMO energy level between the work function of cathode 12 and the LUMO energy level of electron transport layer 26.

[0072] As described above, the light-emitting mechanism 20 includes a hole injection layer 21, a hole transport layer 22, an electron injection layer 27, and an electron transport layer 26 located between the anode 11 and the cathode 12. The interference reflector 30 is disposed between the anode 11 and the cathode 12, separate from the light-emitting mechanism 20. The interference reflector 30 is therefore located at a different position than the hole injection layer 21, hole transport layer 22, electron injection layer 27, and electron transport layer 26. The interference reflector 30 is configured to... Figure 1 The hole injection layer 21 in the organic light-emitting unit 1 shown is in contact.

[0073] The interference reflector 30 includes a p-type low-refractive-index layer 31 having p-type conductivity and a low refractive index, serving as a first charge-generating layer having a first type of conductivity and a first refractive index. The interference reflector 30 also includes an n-type high-refractive-index layer 32 having n-type conductivity and a high refractive index, serving as a second charge-generating layer having a second type of conductivity and a second refractive index. The p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 are alternately stacked in the interference reflector 30. Figure 1 The interference reflector 30 shown is disposed between the anode 11 and the light-emitting layer 24, and is in contact with the anode 11. Materials with p-type conductivity have hole transport capability. Materials with n-type conductivity have electron transport capability.

[0074] Both the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 have refractive indices and film thicknesses defined according to the emission wavelength. For example, the p-type low-refractive-index layer 31 may have a refractive index equal to or greater than 1.4 and equal to or less than 1.6. The n-type high-refractive-index layer 32 may have a refractive index equal to or greater than 2.0 and equal to or less than 2.2. The p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 exhibit a refractive index difference of at least 0.4.

[0075] When the emitted light has a red visible spectrum, the p-type low refractive index layer 31 can have a film thickness of approximately 120 nm. When the emitted light has a red visible spectrum, the n-type high refractive index layer 32 can have a film thickness of approximately 70 nm. When the emitted light has a green visible spectrum, the p-type low refractive index layer 31 can have a film thickness of approximately 90 nm. When the emitted light has a green visible spectrum, the n-type high refractive index layer 32 can have a film thickness of approximately 70 nm. When the emitted light has a blue visible spectrum, the p-type low refractive index layer 31 can have a film thickness of approximately 65 nm. When the emitted light has a blue visible spectrum, the n-type high refractive index layer 32 can have a film thickness of approximately 55 nm.

[0076] The film thicknesses of the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 can be determined based on the emission wavelength and the refractive index. More specifically, the total film thickness of the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 can be determined to satisfy a condition that it is one-quarter of the intralayer wavelength calculated by dividing the emission wavelength by the refractive index. For example, the film thickness of each layer can have an error of 10% or less. Both the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 in the interference reflector 30 have optimal film thicknesses for the wavelength of the emitted light of the desired color.

[0077] The emission spectrum of the light-emitting layer 24 demonstrates the result of the microcavity effect generated between the first and second reflective surfaces opposite to each other. This description defines the optical distance between the first and second reflective surfaces as L, and the peak wavelength of the emitted light as λ. The description also defines the observation angle of the light emitted from the element as θ, measured relative to a 0° observation angle directly in front of the element. The description further defines the sum of the phase shifts in the reflections of the emitted light at the first and second reflective surfaces as... The optical distance L is equal to the total optical film thickness of the organic compound layer disposed between the first and second reflective surfaces. This optical film thickness is calculated by multiplying the actual film thickness by the refractive index. When the emitted light is actually reflected at the first and second reflective surfaces, the sum of phase shifts φ varies depending on the material composition of the reflective interfaces. If these parameters have a relationship that satisfies the following expression (1), the emitted light can be enhanced by a resonance effect.

[0078] [Expression 1]

[0079]

[0080] The cathode 12 of the organic light-emitting unit 1 serves as a first reflective surface. The interference reflector 30 includes a plurality of second reflective surfaces defined by the interface between a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32. When light emitted from the light-emitting layer 24 and light reflected by the cathode 12 propagate from one of the n-type high-refractive-index layers 32 to one of the p-type low-refractive-index layers 31, they are reflected with a predetermined reflectivity. Changing the optical film thickness of the light-emitting mechanism 20 and the interference reflector 30 allows for tuning of the peak wavelength that is most enhanced by the resonance effect.

[0081] Figures 2 to 4 All are graphs, which show exemplary simulations of the reflectance corresponding to different numbers of pairings of the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32. Figure 2 An exemplary simulation corresponding to emitted light having a red visible spectrum is shown. Figure 3 An exemplary simulation corresponding to emitted light with a green visible spectrum is shown. Figure 4 An exemplary simulation corresponding to emitted light having a blue visible spectrum is shown.

[0082] exist Figure 2 In the exemplary simulation of red light shown, curve CV11 represents the reflectance of an electrode with an ITO / Ag / ITO three-layer structure, the electrode being made of ITO films with thin silver films held between the ITO films. Curve CV12 represents the reflectance of a layered product comprising three pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV13 represents the reflectance of a layered product comprising four pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV14 represents the reflectance of a layered product comprising five pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV15 represents the reflectance of a layered product comprising six pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV16 represents the reflectance of a layered product comprising seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV17 represents the reflectance of a layered product comprising eight pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV18 represents the reflection factor of a layered product comprising nine pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32.

[0083] exist Figure 3In the exemplary simulation of the green light shown, curve CV21 represents the reflectance of an electrode with an ITO / Ag / ITO three-layer structure. Curve CV22 represents the reflectance of a layered product comprising a single pair of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV23 represents the reflectance of a layered product comprising two pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV24 represents the reflectance of a layered product comprising three pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV25 represents the reflectance of a layered product comprising four pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV26 represents the reflectance of a layered product comprising five pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV27 represents the reflectance of a layered product comprising six pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV28 represents the reflectance of a layered product comprising seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32.

[0084] exist Figure 4 In the exemplary simulation of blue light shown, curve CV31 represents the reflectance of an electrode with an ITO / Ag / ITO three-layer structure. Curve CV32 represents the reflectance of a layered product comprising a single pair of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV33 represents the reflectance of a layered product comprising two pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV34 represents the reflectance of a layered product comprising three pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV35 represents the reflectance of a layered product comprising four pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV36 represents the reflectance of a layered product comprising five pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV37 represents the reflectance of a layered product comprising six pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Curve CV38 represents the reflectance factor of a layered product comprising seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32.

[0085] These exemplary simulations reveal that the interference reflector 30 preferably includes at least seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32 to achieve a reflectance factor that is substantially equal to at least 90% of the reflectance factor of an electrode comprising an ITO / Ag / ITO three-layer structure. Figure 1The interference reflector 30 shown includes seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. In this interference reflector 30 of the organic light-emitting unit 1, seven p-type low-refractive-index layers 31 with p-type conductivity and low refractive index corresponding to a first charge generation layer having a first type of conductivity and a first refractive index, and seven n-type high-refractive-index layers 32 with n-type conductivity and high refractive index corresponding to a second charge generation layer having a second type of conductivity and a second refractive index, are stacked alternately on top of each other.

[0086] A p-type low-refractive-index layer 31 exhibiting p-type conductivity as a first type of conductivity can be formed using a Lewis acid compound (such as molybdenum trioxide (MoO3)) as an electron acceptor compound. The p-type low-refractive-index layer 31 can also achieve p-type conductivity as a first type of conductivity by adding any inorganic material acting as an electron acceptor additive to an organic material acting as a hole transport material through stacking or mixing. Mixing can include doping. Examples of inorganic materials include vanadium pentoxide (V2O5), rhenium heptaoxide (Re2O7), other metal oxides, and metal halides. Alternatively, p-type conductivity as a first type of conductivity can be achieved by doping the host organic material acting as a hole transport material with any organic dopant represented by a specific chemical formula and acting as an electron acceptor additive. Examples of such organic dopant include organic materials having fluorine, cyano, or other substituents, as well as titanyl phthalocyanine or other phthalocyanine compounds exhibiting p-type conductivity, and hexaazabenzphenanthrene (HAT) derivatives such as hexaazabenzphenanthrene hexanitrile (HAT-CN). In other words, each of the p-type low-refractive-index layers 31 is an organic material layer with electron acceptor capability, and is made by doping the host transport material, which acts as a charge transport material, with impurities that have p-type conductivity.

[0087] The n-type high refractive index layer 32, exhibiting n-type conductivity as a second type of conductivity, can be formed using lithium fluoride (LiF), which is an electron donor compound. The n-type high refractive index layer 32 can also achieve n-type conductivity as a second type of conductivity by adding any inorganic material acting as an electron donor additive to an organic material acting as an electron transport material through stacking or mixing. Mixing can include doping. Examples of inorganic materials include cesium fluoride (CsF), barium oxide (BaO), other alkali metals, alkaline earth metals, their compounds, and rare earth metals. Alternatively, n-type conductivity as a second type of conductivity can be achieved by doping the host organic material acting as an electron transport material with any organic dopant represented by a specific chemical formula and acting as an electron donor additive. Examples of such organic dopant include antimony phthalocyanine compounds and other phthalocyanine compounds exhibiting n-type conductivity. In other words, each of the n-type high refractive index layers 32 is an organic material layer with donor capability and is made by doping the host transport material acting as a charge transport material with impurities exhibiting n-type conductivity.

[0088] For example, by introducing any of the organic materials containing boron coordination compounds, such as fused heterocyclic aromatic rings containing nitrogen and boron, organic materials with fluorine groups, and other inorganic and organic materials with low refractive indices, the p-type low refractive index layer 31 can achieve a low refractive index as a first refractive index. For example, by introducing any of the aromatic amine derivatives, carbazole derivatives, benzimidazole derivatives, triazole derivatives, and other inorganic and organic materials with high refractive indices, the n-type high refractive index layer 32 can achieve a high refractive index as a second refractive index.

[0089] Figure 5 This is a cross-sectional view of a red light-emitting unit 1R, a green light-emitting unit 1G, and a blue light-emitting unit 1B, or three primary color light-emitting sub-units, and a driving TFT 41 for driving each light-emitting unit. According to this embodiment, the organic light-emitting unit 1 is applied to each of the red light-emitting unit 1R, the green light-emitting unit 1G, and the blue light-emitting unit 1B. The red light-emitting unit 1R includes an interference reflector 30R, which is configured by adjusting the interference reflector 30 of the organic light-emitting unit 1 according to this embodiment for the red visible spectrum. The green light-emitting unit 1G includes an interference reflector 30G, which is configured by adjusting the interference reflector 30 of the organic light-emitting unit 1 according to this embodiment for the green visible spectrum. The blue light-emitting unit 1B includes an interference reflector 30B, which is configured by adjusting the interference reflector 30 of the organic light-emitting unit 1 according to this embodiment for the blue visible spectrum.

[0090] Figure 5A pixel definition layer (PDL) 42 is also shown. The pixel definition layer 42 is a resin layer with an opening pattern. Each opening of the pixel definition layer 42 exposes an anode 11 included in a red light-emitting unit 1R, a green light-emitting unit 1G, or a blue light-emitting unit 1B. The pixel definition layer 42 separates adjacent light-emitting units (including red light-emitting unit 1R, green light-emitting unit 1G, and blue light-emitting unit 1B) from each other.

[0091] A red light-emitting unit 1R, an associated driving TFT 41, a switching TFT that feeds a scan signal at a gate, and a pixel circuit having a storage capacitor for holding a pixel signal constitute a red light-emitting sub-pixel 101R that emits red light. A green light-emitting unit 1G, an associated driving TFT 41, a switching TFT, and a pixel circuit having a storage capacitor constitute a green light-emitting sub-pixel 101G that emits green light. A blue light-emitting unit 1B, an associated driving TFT 41, a switching TFT, and a pixel circuit having a storage capacitor constitute a blue light-emitting sub-pixel 101B that emits blue light. The driving TFT 41 is manufactured using known techniques and is conductive to the anode 11 of the associated light-emitting unit at a location below the pixel definition layer 42. Each of the red light-emitting unit 1R, the green light-emitting unit 1G, and the blue light-emitting unit 1B receives driving current from a power line via the driving TFT 41 associated with the light-emitting unit. The driving TFT 41 controls the driving current flowing in the red light-emitting unit 1R, the green light-emitting unit 1G, or the blue light-emitting unit 1B based on the voltage level of the pixel signal held by the storage capacitor. The red light-emitting sub-pixel 101R, the green light-emitting sub-pixel 101G, and the blue light-emitting sub-pixel 101B are also referred to as sub-pixels.

[0092] In the organic light-emitting unit 1 used as the red light-emitting unit 1R, the light-emitting layer 24 presents a red visible spectrum as an exemplary first color. Figure 5 The interference reflector 30R shown is stacked on the anode 11 included in the red light-emitting unit 1R. The p-type low refractive index layer 31 and the n-type high refractive index layer 32 in the interference reflector 30R both have refractive indices and film thicknesses defined according to the red visible spectrum.

[0093] In the organic light-emitting unit 1 used as the green light-emitting unit 1G, the light-emitting layer 24 presents a green visible spectrum as an exemplary second color. Figure 5 The interference reflector 30G shown is stacked on the anode 11 included in the green light-emitting unit 1G. The p-type low refractive index layer 31 and the n-type high refractive index layer 32 in the interference reflector 30G both have refractive indices and film thicknesses defined according to the green visible spectrum.

[0094] In the organic light-emitting unit 1 used as the blue light-emitting unit 1B, the light-emitting layer 24 presents the blue visible spectrum as an exemplary third color. Figure 5 The interference reflector 30B shown is stacked on the anode 11 included in the blue light-emitting unit 1B. Both the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 in the interference reflector 30B have refractive indices and film thicknesses defined according to the blue visible spectrum. The first to third colors can be any combination of colors with different wavelengths.

[0095] like Figure 5 As shown, the circuit board 10, on which the anode 11 and cathode 12 face each other, is divided into first, second, and third regions corresponding to red light-emitting units 1R, green light-emitting units 1G, and blue light-emitting units 1B, respectively. Each first region on the circuit board 10 has a light-emitting layer 24, exhibiting a red visible spectrum and included in the red light-emitting unit 1R, disposed between the anode 11 and cathode 12, and an interference reflector 30R for the red visible spectrum disposed on and in contact with the anode 11. Each second region on the circuit board 10 has a light-emitting layer 24, exhibiting a green visible spectrum and included in the green light-emitting unit 1G, disposed between the anode 11 and cathode 12, and an interference reflector 30G for the green visible spectrum disposed on and in contact with the anode 11. Each third region on the circuit board 10 has a light-emitting layer 24, exhibiting a blue visible spectrum and included in the blue light-emitting unit 1B, disposed between the anode 11 and cathode 12, and an interference reflector 30B for the blue visible spectrum disposed on and in contact with the anode 11.

[0096] The organic light-emitting unit 1 includes an interference reflector 30 and eliminates the need for reflective electrodes made of metal films, thereby reducing optical losses near the electrodes caused by surface plasmon oscillator effects. Reduced optical losses lead to improved luminous efficiency. The resonant region in the microcavity structure is electrode-free, thus avoiding light absorption by the electrodes and further improving luminous efficiency.

[0097] The circuit board 10 includes multiple pixel circuits. These pixel circuits control the current fed to the individual anodes 11 of the multiple sub-pixels. Figure 6A This is a circuit diagram showing pixel circuit PX01 as an exemplary first pixel circuit. Figure 6B This is a circuit diagram showing a pixel circuit PX02 as an example of a second pixel circuit. The circuit board 10 includes a plurality of pixel circuits PX01 or a plurality of pixel circuits PX02 as pixel circuits.

[0098] Figure 6AThe pixel circuit PX01 shown includes transistors Tr01 to Tr03 and a storage capacitor Cs01, and can control the light emission from a light-emitting element E1, such as an organic light-emitting unit 1 used as an OLED element. The anode An of the light-emitting element E1 corresponds to anode 11. The cathode CA of the light-emitting element E1 corresponds to cathode 12. Transistors Tr01 to Tr03 are all p-type TFTs. Transistor Tr01 is a driving TFT 41 associated with the light-emitting element E1. Transistor Tr02 is a TFT used as a switch TFT for controlling the wiring of image signals and also serves as a switch for selecting sub-pixels. Transistor Tr03 is a TFT used as a light-emitting transistor for controlling light emission and also serves as a switch for controlling the start and stop of feeding drive current to the light-emitting element E1.

[0099] The gate terminal of transistor Tr01 is connected to the drain terminal of transistor Tr02. The source terminal of transistor Tr01 is connected to drive power line 141. Drive power line 141 is fed with drive voltage VDD. The drain terminal of transistor Tr01 is connected to the source terminal of transistor Tr03. Storage capacitor Cs01 is connected between the gate terminal and the source terminal of transistor Tr01.

[0100] The gate terminal of transistor Tr02 is connected to scan line 142. The source terminal of transistor Tr02 is connected to data line 143. The drain terminal of transistor Tr02 is connected to the gate terminal of transistor Tr01.

[0101] The gate terminal of transistor Tr03 is connected to the emitter control line 144. The source terminal of transistor Tr03 is connected to the drain terminal of transistor Tr01. The drain terminal of transistor Tr03 is connected to the anode AN of light-emitting element E1. The cathode CA of light-emitting element E1 is fed with cathode voltage VEE.

[0102] Scan line 142 transmits a selection pulse from a component such as a scan driver included in a display device. In response to the selection pulse, transistor Tr02 switches from a cutoff state to a conduction state. Data line 143 is fed with the data voltage VDATA included in each image signal from a component such as a driver IC included in the display device. The conduction state of transistor Tr02 causes the data voltage VDATA to be stored as a pixel signal in storage capacitor Cs01. Storage capacitor Cs01 holds the stored voltage for one frame period. The voltage held by storage capacitor Cs01 changes the conductance of transistor Tr01 in analog form. Therefore, transistor Tr01 feeds a forward bias current to the light-emitting element E1 corresponding to the light emission level.

[0103] Transistor Tr03 is located on the path that feeds the drive current. Emitter control line 144 transmits control signals from components such as the emitter driver of a display device. The control signals in emitter control line 144 are used to control the activation or deactivation of transistor Tr03. When transistor Tr03 is in the on state, drive current is fed to the light-emitting element E1. When transistor Tr03 is in the off state, drive current feeding is stopped. This control of the activation and deactivation of transistor Tr03 adjusts the duty cycle, which indicates the lighting period within one field cycle.

[0104] Figure 6B The pixel circuit PX02 shown includes transistor Tr04, instead of transistor Tr03 in pixel circuit PX01. Transistor Tr04 controls the electrical connection between reference voltage supply line 145 and the anode AN of the light-emitting element E1. Reference voltage supply line 145 is fed with a reference voltage VREF. The gate terminal of transistor Tr04 is connected to reset control line 146. Reset control line 146 transmits a reset control signal output from a component such as the reset IC of the display device. The reset control signal in reset control line 146 is used to control the activation or deactivation of transistor Tr04.

[0105] Transistor Tr04 can also be used to reduce crosstalk caused by leakage current between light-emitting elements E1. For example, transistor Tr04 can reset the anode AN of light-emitting element E1 to a sufficiently low voltage equal to or lower than the black signal level.

[0106] Transistor Tr04 can also be used to measure the characteristics of transistor Tr01, which acts as the driver transistor. For example, a bias condition can be selected where transistor Tr01 operates in the saturation region and transistor Tr04 operates in the linear region. Under this bias condition, the voltage-to-current conversion characteristics of transistor Tr01 can be accurately determined by measuring the current flowing from the drive power supply line 141 with a drive voltage VDD to the reference voltage supply line 145 with a reference voltage VREF. Differences in the voltage-to-current conversion characteristics between transistors Tr01 included in different sub-pixels can be compensated for by a data signal generated by an external circuit. This compensation allows the display device to produce a display image with high uniformity.

[0107] Transistor Tr04 can also be used to accurately measure the voltage-current characteristics of the light-emitting element E1. For example, when transistor Tr01 is in the off state, transistor Tr04 operates in the linear region. In this case, the voltage for emitting light from the light-emitting element E1 is fed from the reference voltage supply line 145. For example, the degradation of the light-emitting element E1 after prolonged use can be compensated by a data signal generated by an external circuit. This compensation can extend the lifespan of the display device.

[0108] Circuit board 10 can also be configured with having a similar Figure 6A The pixel circuit PX01 shown is Figure 6B The pixel circuit PX02 shown represents a pixel circuit with different circuit configurations. Transistors Tr01 to Tr04 can be n-type TFTs, not p-type TFTs. Pixel circuits PX01, PX02, and others only need to compensate for variations in the threshold voltage of transistor Tr01, which acts as the driving transistor, thereby preventing image quality degradation. Display irregularities not adequately suppressed by the pixel circuits can be mitigated by any technique designed to reduce differences in transistor characteristics.

[0109] Figure 7 Bar charts BC01 to BC03 are shown for comparing optical loss and luminous efficiency revealed by optical simulations. Bar chart BC01 represents the optical loss ratio due to the surface plasmon oscillator effect. Bar chart BC02 represents the absorptivity of the anode (such as an ITO layer). Bar chart BC03 represents the luminous efficiency ratio compared to existing structures. The x-axis represents structure PD01 according to an embodiment of this disclosure, and is accompanied by a comparative example including technical feature KA01, technical feature KA03, and existing structure SA01. Technical feature KA01 indicates a structure similar to that disclosed in unexamined Japanese Patent Application Publication No. 2007-317591. Specifically, this structure includes an ITO layer as an anode, a dielectric mirror made by stacking a high-refractive-index dielectric layer and a low-refractive-index dielectric layer on top of each other below the ITO layer, and a light-reflecting layer below the dielectric mirror. Technical feature KA03 indicates a structure similar to that disclosed in U.S. Patent Application Publication No. 2015 / 0041768. Specifically, the structure includes an ITO layer as the anode and a reflective mechanism formed by stacking a high-refractive-index copolymer layer and a low-refractive-index copolymer layer on top of each other on the lower part of the back side of the TFT substrate. The existing structure SA01 includes a reflective metal electrode as the anode. Bar charts BC01 to BC03 illustrate all the results provided by optical simulations in this disclosure.

[0110] By calculating the Purcell factor, the optical loss ratio, represented by the histogram BC01, can be obtained as the optical loss caused by the surface plasmon oscillator effect. The existing structure SA01 exhibits an optical loss ratio of almost 60%. In contrast, the technical features KA01 and KA03, which include an ITO layer as the anode, exhibit a reduced optical loss ratio of approximately 10%. The structure PD01 (including the interferometer 30 above the anode 11) according to an embodiment of this disclosure exhibits a further reduced optical loss ratio of approximately 5%.

[0111] The bar chart BC02 represents the absorptivity of the anode formed in the microcavity structure. Technical feature KA01 includes a dielectric mirror beneath the anode, made of ITO, serving as the first electrode. The dielectric mirror in technical feature KA01 functions as an optical resonator. Technical feature KA03 includes a TFT array substrate and an optical component beneath the anode, made of ITO, serving as the first electrode. The optical component in technical feature KA03 selectively reflects light having a wavelength corresponding to the emission color of the emitting layer. These structures all allow light emitted from the emitting layer and light reflected by the reflecting mechanism to repeatedly pass through the anode made of ITO. Therefore, technical features KA01 and KA03 require a relatively large film thickness of the ITO layer to achieve a thin-film resistance comparable to, for example, the existing three-layer structure SA01 of ITO / Ag / ITO. This relatively thick ITO layer absorbs more light. Similar to the existing structure SA01, the structure PD01 (including an interference reflector 30 above the anode 11) according to an embodiment of this disclosure exhibits a substantially 0% absorptivity.

[0112] The bar chart BC03 represents the luminous efficiency ratio. Technical features KA01 and KA03 exhibit essentially the same luminous efficiency as the existing structure SA01. In contrast, the structure PD01 (including the interference reflector 30 above the anode 11) according to an embodiment of this disclosure can achieve a luminous efficiency more than 1.5 times that of the existing structure SA01. As described above, the structure PD01 including the interference reflector 30 according to an embodiment of this disclosure does not require a reflective electrode made of a metal electrode and prevents light absorption by the anode made of ITO, thereby achieving improved luminous efficiency.

[0113] Light emitted from an organic light-emitting element (OLED) with components parallel to its light-emitting surface is partially reflected and cannot be completely extracted to the outside. Improving this light extraction efficiency can further improve the luminous efficiency of the OLED. To improve the light extraction efficiency, the organic light-emitting unit 1 can have a microlens structure as an external or internal structure.

[0114] Figure 8A and 8B These are schematic diagrams illustrating an exemplary structure of the light extraction layer 50, which can be used as an external structure of the organic light-emitting unit 1. The organic light-emitting unit 1 has a sealing layer 51 disposed thereon. For example, the sealing layer 51 is made of hard glass or a flexible, transparent inorganic or organic material. The light extraction layer 50 is stacked on the sealing layer 51. Figure 8A The light extraction layer 50 shown has a polarizing plate 52 disposed thereon. Figure 8B The light extraction layer 50 shown has a color filter 53, a black matrix 54 and an anti-reflection layer 55 disposed thereon. Figure 8AAlternatively, the light extraction layer 50 shown in 8B is located in a plane different from that of the circuit board 10, outside of the anode 11 and cathode 12 that are opposite to each other on the circuit board 10.

[0115] The light extraction layer 50 includes a high-refractive-index portion 50A and a low-refractive-index portion 50B. The high-refractive-index portion 50A overlaps with the light-emitting layer 24 or other components of the organic light-emitting unit 1 in a direction perpendicular to the plane of the circuit board 10, the light-emitting layer 24, or another layer. The high-refractive-index portion 50A is adjacent to the top of the low-refractive-index portion 50B. In contrast, each low-refractive-index portion 50B does not overlap with the light-emitting layer 24 or other components of the organic light-emitting unit 1, but overlaps with the pixel definition layer 42 in a direction perpendicular to the plane of the circuit board 10, the light-emitting layer 24, or another layer. The low-refractive-index portion 50B surrounds the light-emitting layer 24 or other components of the organic light-emitting unit 1. The low-refractive-index portion 50B has a gradually decreasing thickness in a direction parallel to the plane of the circuit board 10, the light-emitting layer 24, or another layer, from the side of the pixel definition layer 42 away from the light-emitting layer 24 or other components of the organic light-emitting unit 1 to the side closer to the light-emitting layer 24 or other components of the organic light-emitting unit 1, thus defining a curved edge. In other words, the thickness of the low refractive index portion 50B increases in a curved shape in a plane parallel to the circuit board 10, the light-emitting layer 24, or another layer, from the closer side to the light-emitting layer 24 of the organic light-emitting unit 1 or other components to the farther side.

[0116] Figure 8A The light extraction layer 50 shown in diagram 8B allows light emitted vertically from the organic light-emitting unit 1 to propagate linearly in the high-refractive-index portion 50A, as indicated by arrow LP1, and then be extracted to the outside. In contrast, light emitted diagonally from the organic light-emitting unit 1 is refracted at the light extraction layer 50, as indicated by arrows LP2 or LP3. According to the principle of light refraction, when light travels from a medium with a high refractive index to a medium with a low refractive index, light with an angle of incidence greater than the critical angle is totally internally reflected. As indicated by arrows LP2 or LP3, the light from the organic light-emitting unit 1 is deflected vertically because it is totally internally reflected at the interface between the high-refractive-index portion 50A and the low-refractive-index portion 50B. This structure increases the likelihood of light being emitted from the organic light-emitting unit 1 to the outside, thereby achieving improved light extraction efficiency.

[0117] Display devices including organic light-emitting units can have touch panel functionality. In this modification, Figure 8A Alternatively, the light extraction layer 50 shown in 8B can be mounted on the wiring TW of the touch panel.

[0118] Figure 8AThe polarizer 52 shown serves as an anti-reflective film to prevent visibility impairment due to reflection of external light. However, the polarizer 52 not only blocks external light but also blocks a portion of the light emitted from the organic light-emitting unit 1, thus hindering improvements in luminous efficiency. The polarizer 52 has a certain thickness, thus hindering reductions in thickness and improvements in flexibility. In contrast, Figure 8B The color filter 53, black matrix 54, and anti-reflective layer 55 shown improve luminous efficiency while reducing external light reflection, thus facilitating thickness reduction and increased flexibility. For example, the color filter 53 can block external light with wavelengths other than a specific wavelength, thereby enhancing the monochromaticity of the organic light-emitting unit 1. The black matrix 54 can absorb external light and reflected light. Therefore, Figure 8B The color filter 53, black matrix 54, and anti-reflective layer 55 shown can eliminate the effects of color filtering on the skin. Figure 8A The polarizer 52 shown is required or a circular polarizer used as a delay film.

[0119] Figure 9 This is a schematic diagram showing a microlens array 60 that can be used as the internal structure of an organic light-emitting unit 1. Figure 9 The circuit board 10 shown has a smoothing layer 61 on it. On top of the smoothing layer 61 are an organic light-emitting unit 1, a light-emitting mechanism 20, and an interference reflector 30, comprising an anode 11 and a cathode 12 facing each other, forming a microlens array 60. An outer coating layer 62 is provided on the microlens array 60. On top of the outer coating layer 62, all or some of the following may be provided: a wavelength conversion layer, a passivation layer, a surface film, and a protective film.

[0120] Beneath the outer coating 62, the anode 11, cathode 12, light-emitting mechanism 20, and interference reflector 30 are arranged along the shapes of the local maximum, inclined, and local minimum portions of the surface of the outer coating 62, forming a microlens array. The local minimum portion is formed by a portion of the microlens array 60 containing two or more microlenses adjacent to each other. The local maximum portion is formed by the central portion of the microlens. The inclined portion is formed by the portion between the local maximum and local minimum portions. The components of the organic light-emitting unit 1 in the microlens array 60, such as the anode 11, cathode 12, light-emitting mechanism 20, and interference reflector 30, have the same shapes as the local maximum, local minimum, and inclined portions of the microlenses in the outer coating 62.

[0121] The light generated by the light-emitting mechanism 20 is repeatedly reflected between the cathode 12 and the interference reflector 30. The shape of the microlens changes the direction of light propagation to be perpendicular to the plane of the circuit board 10. The microlens array 60 is arranged over the entire light-emitting area of ​​the organic light-emitting unit 1. This structure increases the possibility of light being emitted from the organic light-emitting unit 1 to the outside, thereby achieving improved light extraction efficiency.

[0122] Figure 10 A bar chart BC10 is shown, comparing the percentage of loss in the light-emitting element as revealed by optical simulation. The x-axis of bar chart BC10 presents the structure PD01 according to an embodiment of this disclosure, and is accompanied by a comparative example including technical features KA02 and KA03 and the prior art structure SA01. Similar to the technology disclosed in unexamined Japanese Patent Application Publication No. 2023-4940, technical feature KA02 includes an organic layer between the light-emitting layer and the anode, each organic layer having a high or low refractive index and n-type or p-type conductivity. Similar to the technology disclosed in U.S. Patent Application Publication No. 2015 / 0041768, technical feature KA03 includes an anode made of ITO and a reflective mechanism formed by stacking a high-refractive-index copolymer layer and a low-refractive-index copolymer layer on the lower side behind the TFT substrate. Prior art SA01 includes a reflective metal electrode as the anode. Bar chart BC10 illustrates the results provided by the optical simulations in this disclosure. The light emitted from the light-emitting element consists of emitted light LE1, loss DL1 caused by material absorption, loss DL2 caused by optical confinement in the organic layer, and optical loss DL3.

[0123] The existing structure SA01 exhibits an optical loss DL3 ratio of almost 60%. Technical features KA02 and KA03 exhibit optical loss DL3 ratios exceeding 70%. Regardless of the light extraction technique employed, such high optical loss inhibits the effective light extraction of these structures. Technical features KA02 and KA03 enhance the microcavity effect and monochromaticity, but suffer from high optical loss.

[0124] In contrast, the structure PD01 (including the interference reflector 30) according to an embodiment of the present disclosure exhibits an optical loss ratio of approximately 5% DL3. The structure PD01 according to an embodiment of the present disclosure also has a loss DL2 caused by optical confinement in the organic layer, which accounts for the majority of the total loss. Therefore, the structure PD01 according to an embodiment of the present disclosure can effectively extract the emitted light using light extraction techniques, thereby achieving a significantly improved luminous efficiency.

[0125] Figure 11A graph comparing the current-voltage characteristics of an organic material layer disposed between an anode 11 and a cathode 12 is shown. This comparison is based on a test element made of the materials of the hole transport layer 22, electron transport layer 26, p-type low-refractive-index layer 31, and n-type high-refractive-index layer 32 of the organic light-emitting unit 1. The test element made of these materials is connected to a test electrode made of the same materials as the anode 11 and cathode 12. The first test element is a monolayer element made of the material of the electron transport layer 26 and having a film thickness of 20 nm. The second test element is a monolayer element made of the material of the hole transport layer 22 and having a film thickness of 20 nm. The third test element is a monolayer element made of the material of the n-type high-refractive-index layer 32 and having a film thickness of 20 nm. The fourth test element is a monolayer element made of the material of the p-type low-refractive-index layer 31 and having a film thickness of 20 nm. The fifth test element is a multilayer element with a film thickness of 40 nm, and includes a layer made of a material of p-type low refractive index layer 31 with a film thickness of 20 nm, and a layer made of a material of n-type high refractive index layer 32 with a film thickness of 20 nm.

[0126] Figure 11 Curve CV51 in the graph shown represents the characteristics of the first test element. Curve CV52 represents the characteristics of the second test element. Curve CV53 represents the characteristics of the third test element. Curve CV54 represents the characteristics of the fourth test element. Curve CV55 represents the characteristics of the fifth test element. The p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 have higher conductivity than the hole transport layer 22 and the electron transport layer 26. The fifth test element, made by stacking the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 on top of each other, has substantially the same conductivity as the fourth test element made of the p-type low-refractive-index layer 31. The interference reflector 30 of the organic light-emitting unit 1 has a multilayer structure including the highly conductive p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32, and therefore can suppress voltage increases compared to charge transport layers such as the hole transport layer 22 and the electron transport layer 26. In other words, the organic light-emitting unit 1, which includes an interference reflector 30 made by stacking a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32 on top of each other, can achieve both lower driving voltage and lower power consumption.

[0127] Figure 12 The energy states of each layer of the organic light-emitting unit 1 are shown. Figure 12The energy states shown include the work function 11W of the anode 11 and the work function 12W of the cathode 12. The energy states of each layer of the light-emitting mechanism 20 include energy state 21E of the hole injection layer 21, energy state 22E of the hole transport layer 22, energy state 23E of the electron blocking layer 23, energy state 24E of the light-emitting layer 24, energy state 25E of the hole blocking layer 25, and energy states 26E of the electron transport layer 26 and the electron injection layer 27. The energy states of each layer of the interference reflector 30 include energy state 31E of the p-type low-refractive-index layer 31 and energy state 32E of the n-type high-refractive-index layer 32. Figure 12 The organic light-emitting unit 1 in the example shown includes two pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Depending on the number of pairs, the energy states may also include additional energy states 31E of the p-type low-refractive-index layers 31 and 32E of the n-type high-refractive-index layers 32. The upper limit of the energy states for each layer represents the LUMO level, which represents the lowest energy orbital in the conduction band, and the lower limit represents the HOMO level, which represents the highest energy orbital in the valence band.

[0128] When a voltage is applied between the anode 11 and the cathode 12, the cathode 12 feeds electrons to the LUMO level of the light-emitting layer 24 via the electron injection layer 27 and electron transport layer 26 of the light-emitting mechanism 20, while the anode 11 feeds holes to the HOMO level of the light-emitting layer 24 via the hole injection layer 21 and hole transport layer 22 of the light-emitting mechanism 30. The electrons and holes fed to the light-emitting layer 24 recombine with each other within the light-emitting layer 24 and generate light.

[0129] The interference reflector 30 of the organic light-emitting unit 1 has a multilayer structure, comprising a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32 with mutually different polarities. This multilayer structure provides a charge-transfer complex formed between the p-type low-refractive-index layer 31, which has electron acceptor capability, and the n-type high-refractive-index layer 32, which has electron donor capability, and enables charge transfer without hindering the feeding of charge carriers to each layer. In other words, this multilayer structure can be fabricated as a low-voltage pn junction multi-unit. Figure 12 In this process, a charge-transfer complex is generated at the interface between the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32 due to the redox reaction. The applied voltage causes holes in the charge-transfer complex to move toward the hole transport layer 22 and electrons to move toward the anode 11. This structure prevents the interference reflector 30 from increasing the voltage between the anode 11 and the cathode 12, and allows charge carriers to be smoothly injected into the hole injection layer 21 from the anode 11 side via the interference reflector 30.

[0130] The electrical properties of the p-type low-refractive-index layer 31 vary depending on the concentration of the p-type dopant, while the electrical properties of the n-type high-refractive-index layer 32 vary depending on the concentration of the n-type dopant. Figure 13 The diagram illustrates the relationship between the driving voltage of the light-emitting element according to this disclosure and the concentration of the n-type dopant material in the n-type high-refractive-index layer 32 (that is, the concentration of the n-type dopant in the n-type high-refractive-index layer). This example assumes that the concentration of the p-type dopant material in the p-type low-refractive-index layer 31 is set to 3%. Figure 14 The diagram illustrates the relationship between the relative ratio of the driving voltage and the concentration of the p-type dopant material in the p-type low-refractive-index layer 31 (i.e., the concentration of p-type dopant in the p-type low-refractive-index layer) when the driving voltage of the light-emitting element according to this disclosure is normalized to the driving voltage under a driving voltage of 1% p-type dopant material in the p-type low-refractive-index layer 31. This example assumes that the concentration of the n-type dopant material in the n-type high-refractive-index layer 32 is set to 4%.

[0131] Figure 13 and Figure 14 The results shown indicate that a certain concentration of n-type dopant in the n-type high-refractive-index layer and a certain concentration of p-type dopant in the p-type low-refractive-index layer facilitates efficient carrier feeding from a multilayer structure comprising a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32. More specifically, the formation of the aforementioned charge-transfer complex preferably involves an n-type dopant concentration in the n-type high-refractive-index layer ranging from 2% to 10% and a p-type dopant concentration in the p-type low-refractive-index layer ranging from 3% to 6%.

[0132] The light-emitting mechanism 20 stacked on the interference reflector 30 can utilize existing component structures, thus being less susceptible to changes in carrier balance, thereby preventing a decrease in luminous efficiency and a shortened lifetime. Carrier balance corresponding to the probability of excited states arising from the recombination of electrons and holes injected from the electrodes contributes to improved external quantum efficiency.

[0133] Figure 15 This is a schematic diagram illustrating a second exemplary structure of the organic light-emitting unit 1 according to this embodiment. Figure 15 In, with Figure 1 The same components have the same reference numerals. Figure 15 The interference reflector 30 of the organic light-emitting unit 1 shown includes an n-type low-refractive-index layer 33 having n-type conductivity and low refractive index, serving as a first charge-generating layer having first-type conductivity and first refractive index. Figure 15 The interference reflector 30 of the organic light-emitting unit 1 shown also includes a p-type high-refractive-index layer 34 with p-type conductivity and high refractive index, serving as a second charge-generating layer with second-type conductivity and second refractive index. Figure 15 In the interference reflector 30 shown, an n-type low-refractive-index layer 33 and a p-type high-refractive-index layer 34 are stacked alternately on top of each other. Figure 15The interference reflector 30 shown is disposed between the anode 11 and the light-emitting layer 24, and is in contact with the anode 11. That is, the layer of the interference reflector 30 can have any combination of p-type or n-type conductivity as a first or second type of conductivity and a first or second refractive index, and low or high refractive index.

[0134] Figure 16 This is a schematic diagram illustrating a third exemplary structure of the organic light-emitting unit 1 according to this embodiment. Figure 16 In, with Figure 1 The same components have the same reference numerals. Figure 16 The light-emitting mechanism 20 of the organic light-emitting unit 1 shown has a series structure comprising two layers between the hole injection layer 21 and the electron injection layer 27, each layer including a hole transport layer 22 to an electron transport layer 26. This series structure further includes an n-type charge generation layer 28 and a p-type charge generation layer 29 between the first layer group (including the hole transport layer 22 to the electron transport layer 26) and the second layer group (including the hole transport layer 22 to the electron transport layer 26). Figure 16 The interference reflector 30 shown is disposed between the anode 11 and the lower light-emitting layer 24, and is in contact with the anode 11.

[0135] Figure 17 Bar charts BC21 and BC22 are shown to compare the percentage of loss between existing structures and embodiments of the present disclosure. The x-axis of bar chart BC21 presents a comparative example of a first monomer structure SA11, a second monomer structure SA12, and a series structure SA13 according to the prior art, including a reflective metal electrode as the anode. The x-axis of bar chart BC22 presents an example of a first monomer structure PD11, a second monomer structure PD12, and a series structure PD13 according to embodiments of the present disclosure.

[0136] Figure 18A An exemplary comparative structure is shown, according to the prior art including a first monomer structure SA11, a second monomer structure SA12, and a series structure SA13, comprising a reflective metal electrode as the anode. The first monomer structure SA11 includes a single light-emitting layer 24, which is applied to a structure corresponding to... Figure 30B The distances DA and DB of region Z01 shown are used as the first resonance condition. The second monomer structure SA12 includes a single luminescent layer 24, which is applied according to... Figure 30B The distances DA and DB in region Z03 shown are used as the second resonance condition. The tandem structure SA13 includes two luminescent layers 24, i.e., applied to... Figure 30B The distances DA and DB of region Z03 shown are used as the luminescent layer 24 for the second resonance condition, and the application corresponding to Figure 30BThe distances DA and DB of region Z02 shown are used as the luminescent layer 24 for the third resonance condition.

[0137] Figure 18B An exemplary structure comprising a first monomer structure PD11, a second monomer structure PD12, and a series structure PD13 according to embodiments of the present disclosure is shown. The first monomer structure PD11 is manufactured by adding an interference reflector 30 to the first monomer structure SA11 according to the prior art, such that the interference reflector 30 is disposed between the anode 11 and the light-emitting layer 24 in contact with the anode 11. The second monomer structure PD12 is manufactured by adding an interference reflector 30 to the second monomer structure SA12 according to the prior art, such that the interference reflector 30 is disposed between the anode 11 and the light-emitting layer 24 in contact with the anode 11. The series structure PD13 is manufactured by adding an interference reflector 30 to the series structure SA13 according to the prior art, such that the interference reflector 30 is disposed between the anode 11 and the lower light-emitting layer 24 in contact with the anode 11.

[0138] Figure 17 The bar charts BC21 and BC22 shown illustrate the results provided by the optical simulations in this disclosure. The light emitted from the light-emitting element consists of emitted light LE1, loss DL1 due to material absorption, loss DL2 due to optical confinement in the organic layer, and optical loss DL3.

[0139] As shown in bar chart BC21, the first single-unit structure SA11 according to the prior art exhibits an optical loss DL3 of almost 50%. The second single-unit structure SA12 according to the prior art exhibits an optical loss DL3 of approximately 15%. The series structure SA13 according to the prior art exhibits an optical loss DL3 of approximately 30%. In contrast, as shown in bar chart BC22, the first single-unit structure PD11 according to an embodiment of the present disclosure exhibits an optical loss DL3 of approximately 15%. The second single-unit structure PD12 according to an embodiment of the present disclosure exhibits an optical loss DL3 of less than 5%. The series structure PD13 according to an embodiment of the present disclosure exhibits an optical loss DL3 of less than 10%. That is, the series structure PD13 including the interferometer 30 according to an embodiment of the present disclosure can reduce the optical loss DL3 and thus achieve a significantly improved luminous efficiency.

[0140] Figure 19AAn exemplary structure of a sub-pixel 502 corresponding to technical features KA01 and KA03 is shown. This sub-pixel 502 includes a light-emitting mechanism 20A, which is located not only above the anode 11A, but also above a portion or all of the inclined portion GA1 of the pixel definition layer 42A and the top GB1 of the pixel definition layer 42A. Therefore, the light-emitting mechanism 20A is configured to contact a portion or all of the inclined portion GA1 and the top GB1 of the pixel definition layer 42A. Figure 19A The pixel definition layer 42A has a pixel opening through which a portion of the anode 11A corresponding to the sub-pixel 502 is exposed. This pixel opening of the pixel definition layer 42A is defined by the inclined portion GA1. Figure 19A Components such as the cathode and the capping layer are not shown.

[0141] Sub-pixel 502 corresponding to technical feature KA01 includes an ITO layer serving as an anode 11A, a dielectric mirror formed by stacking a high-refractive-index dielectric layer and a low-refractive-index dielectric layer below the ITO layer, and a light-reflecting layer below the dielectric mirror. Sub-pixel 502 corresponding to technical feature KA03 includes an anode 11A made of ITO, and a reflective mechanism formed by stacking a high-refractive-index copolymer layer and a low-refractive-index copolymer layer on the lower part behind the TFT substrate. In these sub-pixels 502, the reflective mechanism is not disposed above the inclined portion GA1 or the top GB1 of the pixel definition layer 42A. This structure allows light emitted from the light-emitting mechanism 20A to enter the pixel definition layer 42A through the inclined portion GA1 and the top GB1. For example, light emitted from the light-emitting mechanism 20A propagates through the inclined portion GA1 of the pixel definition layer 42A and dissipates in a lateral direction parallel to the substrate surface, such as... Figure 19A As indicated by arrows A01 and A02 in the diagram. This dissipation reduces the rate at which light is extracted from sub-pixel 502, resulting in insufficient luminous efficiency. Dissipation may also be problematic in the prior art SA01, which includes a reflective metal electrode as the anode 11A.

[0142] Figure 19B An exemplary structure of a sub-pixel 102 corresponding to an embodiment of this disclosure is shown. In the sub-pixel 102, part or all of the organic compound layer including the light-emitting mechanism 20 and the interference reflector 30 is located not only above the anode 11, but also above part or all of the inclined portion GA2 of the pixel definition layer 42 and the top GB2 of the pixel definition layer 41. In this structure, the interference reflector 30 is configured to contact part or all of the inclined portion GA2 of the pixel definition layer 42 and the top GB2 of the pixel definition layer 41. Figure 19BThe pixel definition layer 42 has a pixel opening through which a portion of the anode 11 corresponding to the sub-pixel 102 is exposed. This pixel opening of the pixel definition layer 42 is defined by a slanted portion GA2. Figure 19B Components such as cathode 12 and capping layer 13 are not shown.

[0143] In sub-pixel 102, an interference reflector 30 is disposed between the anode 11 and the light-emitting mechanism 20, and between the pixel definition layer 42 and the light-emitting mechanism 20. That is, the reflector mechanism made of the interference reflector 30 is disposed above part or all of the inclined portion GA2 and the top GB2 of the pixel definition layer 42. This structure allows light emitted from the light-emitting mechanism 20 to be reflected by the interference reflector 30, preventing light from passing through the inclined portion GA2 and the top GB2 of the pixel definition layer 42 and entering the pixel definition layer 40. For example, light emitted from the light-emitting mechanism 20 propagates upwards to the light-emitting surface without passing through the inclined portion GA2 of the pixel definition layer 42, such as... Figure 19B As shown by arrows A11 and A12 in the diagram. This propagation increases the rate at which light is extracted from sub-pixel 102, thereby improving luminous efficiency.

[0144] In sub-pixel 102, part or all of the organic compound layer including the light-emitting mechanism 20 and the interference reflector 30 may not be located above the top GB2 of the pixel definition layer 42, but rather above the anode 11 and the inclined portion GA2 of the pixel definition layer 42. In this structure, the interference reflector 30 may be adjacent to the inclined portion GA2 of the pixel definition layer 42. That is, part or all of the organic compound layer including the light-emitting mechanism 20 and the interference reflector 30 may not only be located above the anode 11, but may also be located at least above the inclined portion GA2 of the pixel definition layer 42.

[0145] Example 2

[0146] The following describes an organic light-emitting unit 2 configured as a bottom-emitting OLED according to Embodiment 2. In the organic light-emitting unit 2 according to Embodiment 2, components that are identical to those in the organic light-emitting unit 1 according to Embodiment 1 have the same reference numerals.

[0147] Figure 20This is a schematic diagram illustrating an exemplary structure of an organic light-emitting unit 2 according to Embodiment 2. The organic light-emitting unit 2 includes an anode 11 and a cathode 12 facing each other on a circuit board 10. The organic light-emitting unit 2 also includes a light-emitting mechanism 20 and an interference reflector 30 disposed between the anode 11 and the cathode 12. The organic light-emitting unit 2 has a multilayer structure on the circuit board 10. The anode 11 is the lower electrode serving as the first electrode in the organic light-emitting unit 2. The cathode 12 is the upper electrode serving as the second electrode in the organic light-emitting unit 2. The anode 11 is any electrode made of a semi-transparent and semi-reflective material. The organic light-emitting unit 2 according to this embodiment does not require metallic reflection from the cathode 12. The cathode 12 can be an existing metal electrode, provided that the interference reflector 30 has sufficient reflective properties. Except that the hole injection layer 21 of the light-emitting mechanism 20 of the organic light-emitting unit 2 is configured to contact the anode 11, the light-emitting mechanism 20 has the same structure as the organic light-emitting unit 1 according to Embodiment 1.

[0148] Figure 20 The interference reflector 30 shown is disposed between the cathode 12 and the light-emitting layer 24, and is in contact with the cathode 12. Each of the p-type low refractive index layer 31 and the n-type high refractive index layer 32 of the interference reflector 30 has an optimal film thickness for the wavelength of the emitted light. Figure 20 The interference reflector 30 of the organic light-emitting unit 2 shown is adjacent to the electron injection layer 27.

[0149] The anode 11 of the organic light-emitting unit 2 serves as a first reflective surface. The interference reflector 30 includes a plurality of second reflective surfaces defined by the interface between the p-type low-refractive-index layer 31 and the n-type high-refractive-index layer 32. When light propagates from the light-emitting mechanism 20 into one of the p-type low-refractive-index layers 31, or from one of the n-type high-refractive-index layers 32 into one of the p-type low-refractive-index layers 31, light emitted from the light-emitting layer 24 and light reflected by the anode 11 are reflected with a predetermined reflectivity. The interference reflector 30 preferably includes at least seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. Figure 20 The interference reflector 30 shown includes seven pairs of p-type low-refractive-index layers 31 and n-type high-refractive-index layers 32. In this interference reflector 30 of the organic light-emitting unit 2, seven p-type low-refractive-index layers 31, which are first charge generating layers having a first type of conductivity and a first refractive index, and seven n-type high-refractive-index layers 32, which are second charge generating layers having a second type of conductivity and a second refractive index, are stacked alternately on top of each other.

[0150] Compared to the existing SA01 structure, the organic light-emitting unit 2, including the interferometer reflector 30, can significantly reduce the optical loss ratio DL3, similar to that based on Figure 10The structure PD01 of the embodiment is shown in the bar chart BC10. Therefore, the organic light-emitting unit 2 can achieve a significantly improved luminous efficiency.

[0151] Alternatively, the interference reflector 30 of the organic light-emitting unit 2 may include an n-type low-refractive-index layer 33 having n-type conductivity and low refractive index as a first charge generating layer having a first type of conductivity and a first refractive index, and a p-type high-refractive-index layer 34 having p-type conductivity and high refractive index as a second charge generating layer having a second type of conductivity and a second refractive index. The n-type low-refractive-index layer 33 and the p-type high-refractive-index layer 34 may be stacked alternately on top of each other. In this variation, the interference reflector 30 of the organic light-emitting unit 2 is disposed between the cathode 12 and the light-emitting layer 24, and is in contact with the cathode 12.

[0152] Alternatively, the light-emitting mechanism 20 of the organic light-emitting unit 2 may have a series structure comprising two layers between the hole injection layer 21 and the electron injection layer 27, each layer comprising a hole transport layer 22 to an electron transport layer 26. This series structure further includes an n-type charge generation layer 28 and a p-type charge generation layer 29 between the first layer group comprising the hole transport layer 22 to the electron transport layer 26 and the second layer group comprising the hole transport layer 22 to the electron transport layer 26. In this variant, the interference reflector 30 of the organic light-emitting unit 2 is disposed between the cathode 12 and the upper light-emitting layer 24, and is in contact with the cathode 12.

[0153] The organic light-emitting unit 2, including the interference reflector 30 in this variant, can also significantly reduce the optical loss ratio. Therefore, the organic light-emitting unit 2 can achieve a significantly improved luminous efficiency. If the organic light-emitting unit 2 is provided with a microlens array as an external or internal structure according to light extraction technology, the organic light-emitting unit 2 can effectively extract light, thereby achieving a further improved luminous efficiency.

[0154] Example 3

[0155] The following describes an organic light-emitting unit 3 including a modified interference reflector 30 according to Embodiment 3. In the organic light-emitting unit 3 according to Embodiment 3, components that are the same as those in the embodiments described above have the same reference numerals.

[0156] Figure 21This is a schematic diagram illustrating an exemplary structure of the organic light-emitting unit 3 according to Embodiment 3. The organic light-emitting unit 3 includes three primary color light-emitting sub-units: a red light-emitting unit 3R, a green light-emitting unit 3G, and a blue light-emitting unit 3B. The red light-emitting unit 3R includes a light-emitting mechanism 20R, which includes a light-emitting layer 24 that emits a red visible spectrum, corresponding to the light-emitting mechanism 20 according to the above embodiment. The green light-emitting unit 3G includes a light-emitting mechanism 20G, which includes a light-emitting layer 24 that emits a green visible spectrum, corresponding to the light-emitting mechanism 20 according to the above embodiment. The blue light-emitting unit 3B includes a light-emitting mechanism 20B, which includes a light-emitting layer 24 that emits a blue visible spectrum, corresponding to the light-emitting mechanism 20 according to the above embodiment.

[0157] Each of the red light-emitting unit 3R, the green light-emitting unit 3G, and the blue light-emitting unit 3B includes an anode 11 and a cathode 12 opposite to each other on the circuit board 10. The red light-emitting unit 3R includes a light-emitting mechanism 20R between the anode 11 and the cathode 12. The green light-emitting unit 3G includes a light-emitting mechanism 20G between the anode 11 and the cathode 12. The blue light-emitting unit 3B includes a light-emitting mechanism 20B between the anode 11 and the cathode 12.

[0158] Figure 21 The red light-emitting unit 3R, green light-emitting unit 3G, and blue light-emitting unit 3B shown include a common interference reflector 30R, 30G, and 30B located between the anode 11 and the cathode 12. This serves as the first interference reflector segment. Figure 21 The shown interferometer reflector 30R is stacked on and in contact with the anode 11 of the red light-emitting unit 3R, the green light-emitting unit 3G, and the blue light-emitting unit 3B. The interferometer reflector 30R includes a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32, each layer having a refractive index and film thickness defined according to the red visible spectrum. [The remaining text appears to be incomplete and possibly refers to a different section.] Figure 21 The interferometer reflector 30G shown is stacked on top of the interferometer reflector 30R. The interferometer reflector 30G includes a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32, each layer having a refractive index and film thickness defined according to the green visible spectrum. [The remaining text appears to be incomplete and possibly refers to a third interferometer reflector segment.] Figure 21 The interferometer 30B shown is stacked on top of the interferometer 30G and is in contact with the hole injection layer 21. The interferometer 30B includes a p-type low-refractive-index layer 31 and an n-type high-refractive-index layer 32, each layer having a refractive index and film thickness defined according to the blue visible spectrum. As described above, Figure 21The organic light-emitting unit 3 shown includes interferometers 30R, 30G, and 30B stacked sequentially in a direction perpendicular to the film thickness direction. The interferometers 30R, 30G, and 30B satisfy the reflection conditions of the visible spectrum associated with the respective emission colors of red, green, and blue.

[0159] Figure 22 It is a graph showing the parameters of the reflectance factor in the organic light-emitting unit 3, which includes interference reflectors 30R, 30G and 30B. Figure 22 Curve CV61 in the diagram shows the reflectance factor of an electrode with an ITO / Ag two-layer structure, fabricated by combining a thin silver film with an ITO film. Curve CV62 shows the reflectance factor of the interferometers 30R, 30G, and 30B included in the organic light-emitting unit 3. The organic light-emitting unit 3, including the interferometers 30R, 30G, and 30B, can appropriately reflect and output red, green, and blue emitted light. The organic light-emitting unit 3 does not require a reflective electrode made of a metal film, thus reducing optical losses and achieving improved luminous efficiency.

[0160] Figure 23 A bar chart BC30 is shown comparing the percentage of losses in the organic light-emitting unit 3. The x-axis of the bar chart BC30 represents the structure PD01 including the organic light-emitting unit 1 according to Embodiment 1, and is accompanied by a comparative example including the structure PD31 including the organic light-emitting unit 3 according to Embodiment 3 and the existing structure SA01 including a reflective metal electrode as an anode. The bar chart BC30 illustrates the results provided by the optical simulations in this disclosure. The light emitted from the light-emitting element consists of emitted light LE1, loss DL1 due to material absorption, loss DL2 due to optical confinement in the organic layer, and optical loss DL3.

[0161] Compared to the structure PD01 according to Embodiment 1, the organic light-emitting unit 3 can further reduce the optical loss ratio DL3, and compared to the existing structure SA01, it can significantly reduce the optical loss ratio DL3. The organic light-emitting unit 3 according to Embodiment 3, comprising sequentially stacked interferometers 30R, 30G, and 30B, can further reduce the optical loss DL3, thereby achieving a significantly improved luminous efficiency. If the organic light-emitting unit 3 is provided with a microlens array as an external or internal structure according to a light extraction technique, the organic light-emitting unit 3 can effectively extract light, thereby achieving a further improved luminous efficiency.

[0162] Figure 24 It is a cross-sectional view of the red light-emitting unit 3R, the green light-emitting unit 3G, and the blue light-emitting unit 3B or the three primary color light-emitting sub-units, as well as the driving TFT 41 used to drive each light-emitting unit. Figure 24The red light-emitting unit 3R, green light-emitting unit 3G and blue light-emitting unit 3B shown are included in the organic light-emitting unit 3 according to embodiment 3. Figure 24 The driving TFT 41 shown is an image Figure 5 It works as shown in the diagram. Figure 24 It also shows with Figure 5 The same pixel definition layer (PDL) 42.

[0163] A red light-emitting unit 3R, an associated driving TFT 41, a switching TFT that feeds a scan signal at the gate, and a pixel circuit having a storage capacitor for holding the pixel signal constitute a red light-emitting sub-pixel 103R that emits red light. A green light-emitting unit 3G, an associated driving TFT 41, a switching TFT, and a pixel circuit having a storage capacitor constitute a green light-emitting sub-pixel 103G that emits green light. A blue light-emitting unit 3B, an associated driving TFT 41, a switching TFT, and a pixel circuit having a storage capacitor constitute a blue light-emitting sub-pixel 103B that emits blue light.

[0164] Figure 24 The structure shown includes a light-emitting layer 24 emitting a red visible spectrum in a red light-emitting unit 3R, a light-emitting layer 24 emitting a green visible spectrum in a green light-emitting unit 3G, and a light-emitting layer 24 emitting a blue visible spectrum in a blue light-emitting unit 3B, located between an anode 11 and a cathode 12. The organic light-emitting unit 3 has an interference reflector 30R completely disposed on the anode 11 for the red visible spectrum, which is an exemplary first color, and in contact with the anode 11. An interference reflector 30G for the green visible spectrum, which is an exemplary second color, is disposed on the interference reflector 30R. An interference reflector 30B for the blue visible spectrum, which is an exemplary third color, is disposed on the interference reflector 30G. The first to third colors can be any combination of colors having different emission wavelengths.

[0165] Alternatively, all or some of the interference reflectors 30R, 30G, and 30B of the organic light-emitting unit 3 may include an n-type low-refractive-index layer 33 having n-type conductivity and low refractive index as a first charge generating layer having a first type of conductivity and a first refractive index, and a p-type high-refractive-index layer 34 having p-type conductivity and high refractive index as a second charge generating layer having a second type of conductivity or a second refractive index. The n-type low-refractive-index layer 33 and the p-type high-refractive-index layer 34 may be stacked alternately on top of each other. In this variant, the interference reflector 30R of the organic light-emitting unit 3 is disposed between the anode 11 and the light-emitting layer 24, on and in contact with the anode 11. The interference reflector 30G of the organic light-emitting unit 3 is disposed on the interference reflector 30R, between the anode 11 and the light-emitting layer 24. The interference reflector 30B of the organic light-emitting unit 3 is disposed on the interference reflector 30G, between the anode 11 and the light-emitting layer 24.

[0166] Alternatively, all or some of the light-emitting mechanisms 20R of the red light-emitting unit 3R, 20G of the green light-emitting unit 3G, and 20B of the blue light-emitting unit 3B in the organic light-emitting unit 3 may have a series structure comprising two layers between the hole injection layer 21 and the electron injection layer 27, each layer comprising a hole transport layer 22 to an electron transport layer 26. This series structure further includes an n-type charge generation layer 28 and a p-type charge generation layer 29 between the first layer group comprising the hole transport layer 22 to the electron transport layer 26 and the second layer group comprising the hole transport layer 22 to the electron transport layer 26. In this variant, the interference reflector 30R of the organic light-emitting unit 3 is disposed between the anode 11 and the light-emitting layer 24, on and in contact with the anode 11. The interference reflector 30G of the organic light-emitting unit 3 is disposed on the interference reflector 30R, between the anode 11 and the light-emitting layer 24. The interference reflector 30B of the organic light-emitting unit 3 is disposed on the interference reflector 30G, between the anode 11 and the light-emitting layer 24.

[0167] The organic light-emitting unit 3 can also be configured as a bottom-emitting OLED. In this variation, the interferometer 30R of the organic light-emitting unit 3 is disposed between the cathode 12 and the light-emitting layer 24, below and in contact with the cathode 12. The interferometer 30G of the organic light-emitting unit 3 is disposed between the cathode 12 and the light-emitting layer 24, below the interferometer 30R. The interferometer 30B of the organic light-emitting unit 3 is disposed between the cathode 12 and the light-emitting layer 24, below the interferometer 30G and in contact with the electron injection layer 27.

[0168] Example 4

[0169] The following describes a display device 90 according to embodiment 4, which includes an organic light-emitting unit according to any of the above embodiments. Figure 25This is a schematic diagram illustrating an exemplary structure of a display device 90 according to this embodiment.

[0170] The display device 90 includes a TFT substrate 110, a sealing substrate 200, and a bonding section (glass sealant) 300, identical to those on the circuit board 10. Any one of organic light-emitting units 1 to 3, serving as OLED elements, is disposed on the TFT substrate 110. The sealing substrate 200 faces the TFT substrate 110. The bonding section 300 is disposed between the TFT substrate 110 and the sealing substrate 200, thereby bonding the TFT substrate 110 and the sealing substrate 200 together and tightly surrounding the OLED element.

[0171] The TFT substrate 110 has a display area 125 and a cathode area 114 surrounding it. A scan driver 131, an emitter driver 132, a protection circuit 133, and a driver integrated circuit (IC) 134 are disposed around the cathode area 114 on the TFT substrate 110. These components are connected to external devices via a flexible printed circuit (FPC) 135.

[0172] Scan driver 131 drives the scan lines of TFT substrate 110. Emission driver 132 drives the emission control lines and controls the emission period of each sub-pixel. Driver IC 134 is implemented, for example, by an anisotropic conductive film (ACF).

[0173] Driver IC 134 provides power and timing (control) signals to scan driver 131 and transmit driver 132, and provides data voltages corresponding to image data to the data lines. In other words, driver IC 134 has display control functions.

[0174] For example, the sealing substrate 200 is a transparent insulating substrate, such as a glass substrate. The light-emitting surface (front surface) of the sealing substrate 200 is provided with a λ / 4 retardation film and a polarizer to reduce the reflection of light incident from the outside.

[0175] Figure 26 This is a plan view of a portion of display area 125. Display area 125 includes multiple sub-pixels. Figure 26 This diagram shows some sub-pixels arranged in a matrix within display area 125. At least three sub-pixels emit light with first to third colors that are different from each other. For example, the first color is typically blue, the second color is typically red, and the third color is typically green. Figure 26 The red sub-pixel (light-emitting area) 251R, blue sub-pixel (light-emitting area) 251B, and green sub-pixel (light-emitting area) 251G are shown. Along... Figure 26 The cross-sectional view taken by line A1-A1 corresponds to Figure 5 Or the cross-sectional view shown in 24. The sub-pixels emitting the first to third colors of light are not necessarily like... Figure 24They are arranged in a strip array as shown.

[0176] Figure 26 Each sub-pixel (light-emitting area) shown is completely covered by an organic light-emitting layer of the same color. Specifically, the red sub-pixel 251R, the blue sub-pixel 251B, and the green sub-pixel 251G are completely covered by the red organic light-emitting layer 269R, the blue organic light-emitting layer 269B, and the green organic light-emitting layer 269G, respectively. Figure 26 The diagram shows representative subpixels among the red, blue, and green subpixels, labeled with reference numerals. Each subpixel emits light of any color among red, blue, and green. The red, blue, and green subpixels constitute a single pixel (the main pixel).

[0177] The sub-pixels in this embodiment are made of any one of the organic light-emitting units 1 to 3 according to embodiments 1 to 3. Due to the effect of any of the structures in embodiments 1 to 3, the sub-pixels can thus achieve improved luminous efficiency.

[0178] Example 5

[0179] The following describes an in-vehicle display 92 according to embodiment 5, which includes a display device 90 according to embodiment 4. Figure 27 This is a schematic diagram showing an in-vehicle display 92 according to this embodiment and a vehicle 95 including these in-vehicle displays 92.

[0180] The vehicle display 92 is installed in, for example Figure 27 The interior of vehicle 95 is shown, displaying various types of information. Examples of in-vehicle displays 92 include... Figure 27 The central information display (CID) 301, dashboard display 302, and landscape display 303 shown are described. According to this embodiment, the CID 301, dashboard display 302, and landscape display 303 can be implemented by the display device 90.

[0181] CID 301 is installed in the center of the instrument panel of vehicle 95 and displays information from systems such as audio systems, navigation systems, and systems for managing vehicle status. Instrument panel display 302 displays the speedometer and other indicators. Lateral displays 303 are installed on the left and right sides of the instrument panel and display images captured by cameras, thus functioning as rearview mirrors.

[0182] Due to sunlight or other factors, the in-vehicle displays 92 inside the vehicle 95 may suffer from insufficient screen visibility. The in-vehicle displays 92 are implemented by a display device 90 including any one of organic light-emitting units 1 to 3, and thus achieve improved luminous efficiency. Therefore, regardless of sunlight conditions, the screens of the in-vehicle displays 92 are able to achieve a preferred display with enhanced visibility.

[0183] The vehicle-mounted display 92 is not necessarily CID 301, dashboard display 302, or landscape display 303; it can be any display installed inside a vehicle. The display device 90 is not necessarily used as the vehicle-mounted display 92 and can also be installed on any industrial transport equipment.

[0184] Example 6

[0185] The following describes a smartphone 98 according to Embodiment 6, which is an electronic device including a display device 90 according to Embodiment 4. Figure 28 This is a perspective view of an exemplary structure of a smartphone 98 as an electronic device. The smartphone 98 includes a housing 401, a display device 90 according to embodiment 4 within the housing 401, and a protective glass 402 mounted on the screen side of the display device 90. The housing 401 also houses several units having the functions required for a smartphone. Examples of these units include transmitting and receiving units, various controllers, memory, an audio unit including a speaker and microphone, and a battery.

[0186] Smartphone 98 is sometimes used in bright environments such as outdoors. The smartphone 98 includes a display device 90, and therefore can achieve improved luminous efficiency. Thus, even in bright environments, the screen of the smartphone 98 can achieve a preferred display with enhanced visibility.

[0187] Display device 90 is not necessarily used in smartphones 98, which are electronic devices. For example, display device 90 can also be used in personal computers, personal digital assistants (PDAs), tablet computers, head-mounted displays, projectors, and digital (video) cameras.

[0188] The above embodiments can be modified in various ways within the scope of this disclosure. For example, considering the characteristics of the device, Figure 8A Or the sealing structure including sealing layer 51 shown in 8B or Figure 25 The sealing structure shown, including the sealing substrate 200 and the joint section 300, can be replaced by any of various structures.

[0189] Figures 29A to 29C All are cross-sectional views of exemplary sealing structures of organic light-emitting units according to any of the embodiments described above. Figure 29A The first sealing structure SE01, comprising two glass substrates, is shown. Figure 29B The second sealing structure SE02, which includes a glass substrate and a thin-film encapsulation (TFE) layer, is shown. Figure 29C A third sealing structure SE03, comprising a polyimide (PI) substrate and a TFE layer, is shown.

[0190] The first sealing structure SE01 tightly surrounds the organic light-emitting unit 210 and the TFT substrate 211 used as a circuit board using a first glass substrate 212, a second glass substrate 213, and a glass adhesive segment 214. The first glass substrate 212 has a thickness of, for example, 0.2 to 0.25 mm. The second glass substrate 213 has a thickness of, for example, 0.4 to 0.5 mm. The glass adhesive segment 214 is disposed between the first glass substrate 212 and the second glass substrate 213, bonding the first glass substrate 212 and the second glass substrate 213 together and surrounding the organic light-emitting unit 210 and the TFT substrate 211. The first sealing structure SE01 is not easily affected by the external environment (e.g., water) and can achieve optimal color reproduction, but it is relatively thick and heavy.

[0191] The second sealing structure SE02 tightly surrounds the organic light-emitting unit 210 and the TFT substrate 211 using a glass substrate 215 and a TFE layer 216. The glass substrate 215 has a thickness of, for example, 0.4 to 0.5 mm. The TFE layer 216 has a thickness of, for example, 20 μm. The TFE layer 216 covers the top of the organic light-emitting unit 210 and the TFT substrate 211 and is bonded to the glass substrate 215 at the edges of the organic light-emitting unit 210 and the TFT substrate 211, thereby tightly surrounding them. In terms of thickness, form factor, security, and weight, the second sealing structure SE02 has better characteristics than the first sealing structure SE01. The second sealing structure SE02 exhibits optimal functional integration.

[0192] The third sealing structure SE03 tightly surrounds the organic light-emitting unit 210 and the TFT substrate 211 using a polyimide layer 217 and a TFE layer 218. The polyimide layer 217 has a thickness of, for example, 20 μm. The TFE layer 218 has a thickness of, for example, 20 μm. The TFE layer 218 covers the top of the organic light-emitting unit 210 and the TFT substrate 211 and is bonded to the polyimide layer 217 at the edges of the organic light-emitting unit 210 and the TFT substrate 211, thereby tightly surrounding them. In terms of weight, the third sealing structure SE03 has better characteristics than the first sealing structure SE01 and the second sealing structure SE02. In terms of thickness, form factor, security, and functional integration, the third sealing structure SE03 exhibits optimal characteristics.

[0193] For illustrative purposes, some exemplary embodiments have been described above. Although specific embodiments have been given in the preceding discussion, those skilled in the art will recognize that changes in form and detail may be made without departing from the broader spirit and scope of the invention. Therefore, the specification and drawings are to be considered illustrative rather than restrictive. Consequently, this detailed description should not be regarded as limiting, and the scope of the invention is defined only by the appended claims and the full scope of their authorized equivalents.

Claims

1. An organic light-emitting unit, comprising: The first and second electrodes are opposite to each other; and An organic compound layer is disposed between the first electrode and the second electrode, and includes at least a light-emitting layer and an interference reflector, wherein... The interference reflector: It includes a first charge-generating layer having a first type of conductivity and a first refractive index, and a second charge-generating layer having a second type of conductivity and a second refractive index, wherein the first charge-generating layer and the second charge-generating layer are stacked alternately on top of each other, and It is configured to contact the first electrode or the second electrode.

2. The organic light-emitting unit according to claim 1, wherein... Each of the first charge-generating layers is a first organic material layer with electron acceptor capability, and the first organic material layer is made by doping a charge transport material with impurities having the first type of conductivity. Each of the second charge-generating layers is a second organic material layer with electron-donating capability, which is made by doping a charge-transporting material with impurities having the second type of conductivity.

3. The organic light-emitting unit according to claim 1, further comprising: A hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer are located between the first electrode and the second electrode, wherein... The interference reflector is located at a position different from the hole injection layer, the hole transport layer, the electron injection layer, and the electron transport layer.

4. The organic light-emitting unit according to claim 3, wherein, The interference reflector is configured to contact the hole injection layer or the electron injection layer.

5. The organic light-emitting unit according to claim 1, wherein... The light-emitting layer includes: The first light-emitting layer segment is disposed in the first region and exhibits a first color of the visible spectrum. The second luminescent layer segment is disposed in the second region and exhibits a visible spectrum of a second color having an emission wavelength different from that of the first color. The third luminescent layer segment is disposed in the third region and exhibits a visible spectrum of a third color having an emission wavelength different from the first and second colors. The interference reflector includes: A first interference reflector segment, disposed in a first region in contact with the first electrode or the second electrode, is designed for use in the visible spectrum of the first color. A second interference reflector segment, disposed in a second region in contact with the first electrode or the second electrode, is designed for the visible spectrum of the second color. A third interference reflector segment is disposed in a third region in contact with the first electrode or the second electrode, and the third interference reflector segment is designed for the visible spectrum of the third color.

6. The organic light-emitting unit according to claim 1, wherein... The light-emitting layer includes: The first light-emitting layer segment is disposed in the first region and exhibits a first color of the visible spectrum. The second luminescent layer segment is disposed in the second region and exhibits a visible spectrum of a second color having an emission wavelength different from that of the first color. The third luminescent layer segment is disposed in the third region and exhibits a visible spectrum of a third color having an emission wavelength different from the first and second colors. The interference reflector includes: A first interference reflector segment, configured to contact the first electrode or the second electrode, is designed for the visible spectrum of the first color. A second interferometer segment, configured to contact the first interferometer segment, is designed for the visible spectrum of the second color. A third interference reflector segment is configured to contact the second interference reflector segment, and the third interference reflector segment is designed for the visible spectrum of the third color.

7. The organic light-emitting unit according to claim 1, further comprising: A light extraction layer is disposed on the outer sides of the first electrode and the second electrode, wherein... The light extraction layer includes: The high refractive index portion overlaps with the light-emitting layer in a direction perpendicular to the plane of the light-emitting layer, and The low-refractive-index portion does not overlap with the light-emitting layer in a direction perpendicular to the plane of the light-emitting layer, and The low-refractive-index portion has a gradually decreasing thickness in the direction from the side away from the light-emitting layer to the side closer to the light-emitting layer, and thus defines a curved edge, the direction being parallel to the plane of the light-emitting layer.

8. The organic light-emitting unit according to claim 1, wherein, The first electrode, the second electrode, the light-emitting layer, and the interference reflector are formed as a microlens array comprising a local maximum portion, a tilted portion, and a local minimum portion.

9. The organic light-emitting unit according to claim 1, wherein... Part or all of the organic compound layer is disposed above the inclined portion of the pixel definition layer, and The interference reflector is configured to contact the tilted portion of the pixel definition layer.

10. A display device comprising an organic light-emitting unit according to any one of claims 1 to 9.

11. An in-vehicle display, comprising the display device according to claim 10.

12. An electronic device comprising the display device according to claim 10.

13. A vehicle comprising an in-vehicle display according to claim 11.

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