Charge generation unit, double-color laminated OLED micro-display and preparation method of double-color laminated OLED micro-display

Abstract

The invention discloses a charge generation unit, a double-color laminated OLED micro-display and a preparation method thereof, in the charge generation unit, a first electron injection layer is formed by doping an alkali metal compound material with low-work-function rare earth metal or high-conductivity metal; the second electron injection layer is formed by doping an organic electron transport layer material with low-work-function rare earth metal or high-conductivity metal; the first hole injection layer adopts an electron-withdrawing material, and the electron-withdrawing material has a deep HOMO energy level or a deep valence band energy level; the hole barrier improvement layer adopts an ultrathin hole injection type dopant; the second hole injection layer adopts a hole transport layer doped with a hole injection dopant, and the hole transport layer has a high HOMO energy level. According to the invention, the problems of low carrier injection / transmission efficiency and recombination imbalance of different light-emitting units in the laminated OLED device are solved, so that the efficiency of the device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microdisplay devices, and in particular, to a charge generation unit, a dual-color stacked OLED microdisplay, and a method for manufacturing the same. Background Art

[0002] A dual-color microdisplay is a display technology based on a stacked OLED (Tandem OLED) structure. By stacking light-emitting units of two different light-emitting colors in the vertical direction and utilizing the microcavity effect, dual-color light emission is achieved, which has the characteristics of high efficiency, high brightness, long lifespan, and high contrast. Such displays are particularly suitable for microdisplay devices, such as fields like augmented reality (AR), virtual reality (VR), precision projection display, etc. However, dual-color microdisplays also face challenges in carrier recombination imbalance and the complexity of color control, which severely restrict their development and application in the microdisplay field.

[0003] Traditional dual-color displays generally use a fine mask process to deposit single-color light-emitting units on different pixels, thereby achieving a dual-color display device through a control circuit. However, high-resolution microdisplay devices have extremely high precision requirements for fine masks. Currently, there are still problems with low mask precision, and the manufacturing process is relatively cumbersome, which limits its application in the preparation of microdisplay devices. Without affecting the display resolution, achieving dual-color emission by depositing the same device structure can effectively avoid the above problems. Based on the microcavity effect and a stacked device with red and green double light-emitting layers, two pixels can emit red and green colors. Therefore, the top-emitting stacked microcavity OLED device has become one of the potential alternative solutions for dual-color display devices. However, there are two types of light-emitting units in the stacked device, and the transport and recombination of carriers inside it are quite different from those of carriers in the same light-emitting unit. The main reason is that the red light-emitting layer usually requires a lower hole injection energy, resulting in holes being more easily injected into the red light layer, and the green light-emitting layer requires a higher electron injection energy, resulting in electrons being more easily accumulated in the green light layer. Therefore, the transport and recombination of carriers inside the dual-color microcavity stacked OLED device are more complex. Reducing the carrier injection / transport barriers between the upper and lower light-emitting units is crucial for improving the carrier recombination of the dual-color microcavity stacked OLED device, thereby improving the luminescence performance and lifespan. The traditional stacked structure OLED device is composed of a charge generation unit (Charge Generation Unit, CGU) connecting two light-emitting units. Among them, the CGU is generally composed of a p-n heterojunction, which can generate electrons and holes under an applied electric field, and then inject them into the adjacent light-emitting units through the electron and hole injection layers respectively. Finally, the holes and electrons injected from the two electrodes undergo radiative recombination to emit light. The CGU in the stacked OLED is the key to affecting the carrier generation and separation efficiency, and its performance determines the injection and transport efficiency of carriers to different red and green light-emitting units, thereby affecting the performance of the entire device. Therefore, to solve the carrier imbalance problem in dual-color microdisplays, introducing an efficient CGU and optimizing the energy level arrangement to reduce interfacial charge accumulation is one of the core challenges for achieving high-efficiency and long-lifespan dual-color microdisplays. Summary of the Invention

[0004] Technical Objective: Aiming at the defects in the prior art, the present invention discloses a charge generation unit, a dual-color stacked OLED microdisplay and its manufacturing method. By reducing the energy level barriers between the electron injection layer and the hole injection layer in the charge generation unit and the adjacent transport layer, the effect of energy level matching is achieved, solving the problems of low carrier injection / transport efficiency and recombination imbalance of different light-emitting units in the stacked OLED device, thereby improving the device efficiency.

[0005] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solutions.

[0006] The present application discloses a charge generation unit, which includes a first electron injection layer, a second electron injection layer, a first hole injection layer, a hole barrier improvement layer, and a second hole injection layer, which are sequentially arranged from top to bottom;

[0007] The first electron injection layer is doped with a low work function rare earth metal or a highly conductive metal using an alkali metal compound material; the second electron injection layer is doped with a low work function rare earth metal or a highly conductive metal using an organic electron transport layer material; the first hole injection layer uses an electron-withdrawing material, and the electron-withdrawing material has a deep HOMO energy level or a deep valence band energy level; the hole barrier improvement layer uses an ultra-thin hole injection type dopant; the second hole injection layer uses a hole transport layer doped with a hole injection dopant, and the hole transport layer has a high HOMO energy level.

[0008] The present application discloses a dual-color stacked OLED microdisplay, which includes a substrate and two groups of dual-color stacked OLED devices located on the substrate. The structures of each group of dual-color stacked OLED devices are the same, and include a reflective anode layer, an organic layer, and a cathode layer, which are sequentially arranged from bottom to top on the substrate; the organic layer includes a first hole injection layer, a second hole injection layer, a first hole transport layer, an electron blocking layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, a charge generation unit, a first hole transport layer, an electron blocking layer, a second light-emitting layer, a second hole blocking layer, a second electron transport layer, a first electron injection layer, and a second electron injection layer; the charge generation unit is a charge generation unit as described above; the first light-emitting layer and the second light-emitting layer use light-emitting units of different colors, and the microcavity lengths of each group of dual-color stacked OLED devices are different, so as to realize the light-emitting display of different colors of the two groups of dual-color stacked OLED devices.

[0009] The present application discloses a preparation method of a dual-color stacked OLED microdisplay, which includes the following steps:

[0010] S1. Prepare a reflective anode layer on a silicon-based CMOS substrate;

[0011] S2. Deposit an organic layer on the reflective anode layer by vacuum evaporation. The organic layer includes a first hole injection layer, a second hole injection layer, a first hole transport layer, an electron blocking layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, a charge generation unit, a first hole transport layer, an electron blocking layer, a second light-emitting layer, a second hole blocking layer, a second electron transport layer, a first electron injection layer, and a second electron injection layer;

[0012] S3. Form a cathode layer on the second electron injection layer by vacuum thermal evaporation or magnetron sputtering.

[0013] Beneficial effects:

[0014] 1. The present invention adopts the energy level barrier optimization technology of the charge generation unit, reduces the interface barrier, improves the charge generation and separation efficiency, promotes the injection / transport of electrons and holes to the light-emitting unit, thereby improving the carrier recombination in the dual-color light-emitting unit, and further improving the device efficiency.

[0015] 2. In the present invention, by designing different cavity lengths for the dual-color stacked OLED devices, the light emission displays of different colors of two groups of dual-color stacked OLED devices are realized, and the light rays to be emitted by each group of dual-color stacked OLED devices are determined by designing the thickness and refractive index of the transparent metal oxide layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of a dual-color stacked OLED device

[0017] Figure 2 It is an energy level diagram of the charge generation unit

[0018] Figure 3 It is a spectral diagram of a red-green dual-color stacked OLED device applying the charge generation unit of the present invention;

[0019] Among them, 001 - silicon-based CMOS substrate, 100 - reflective anode layer, 101 - transparent metal oxide layer, 102 - hole injection layer 1, 103 - hole injection layer 2, 104 - hole transport layer 1, 105 - electron blocking layer, 106 - first light-emitting layer, 107 - hole blocking layer 1, 108 - first electron transport layer, 109 - charge generation unit, 1091 - first electron injection layer, 1092 - second electron injection layer, 1093 - first hole injection layer, 1094 - hole barrier improvement layer, 1095 - second hole injection layer, 110 - first hole transport layer, 111 - electron blocking layer, 112 - second light-emitting layer, 113 - hole blocking layer 2, 114 - second electron transport layer, 115 - electron injection layer 1, 116 - electron injection layer 2, 117 - cathode layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0021] Embodiment 1

[0022] As shown in the attached Figure 2As shown in the figure, a charge generation unit of this embodiment includes a first electron injection layer 1091, a second electron injection layer 1092, a first hole injection layer 1093, a hole barrier improvement layer 1094, and a second hole injection layer 1095, which are sequentially arranged from top to bottom.

[0023] The first electron injection layer 1091 is doped with a low work function rare earth metal or a highly conductive metal using an alkali metal compound material. The alkali metal compound material is one of LiF, CS2CO3, Liq, Ru2CO3, etc.; the low work function rare earth metal is one of europium (Eu) and ytterbium (Yb), etc.; the highly conductive metal is one of Li, Ag, Au, Al, etc. The doping effect of the first electron injection layer is beneficial to reducing the electron injection barrier between the first electron injection layer and the second electron injection layer; at the same time, it improves the thermal stability and chemical stability of the alkali metal compound.

[0024] The second electron injection layer 1092 is doped with a low work function rare earth metal or a highly conductive metal using an organic electron transport layer material; the organic electron transport layer material is one of Bphen, Tmpypb, TPBi, etc.; the thickness range of the first electron injection layer is 5 nm to 15 nm, and the thickness range of the second electron injection layer is 5 nm to 15 nm. The superposition thickness of the first electron injection layer and the second electron injection layer is less than 20 nm. The proportion range of the doping materials of the first electron injection layer and the second electron injection layer is 10% to 30%. Their thickness and doping ratio can affect the electron injection and transport capabilities, thereby affecting the carrier recombination efficiency; the doping effect of the second electron injection layer is beneficial to reducing the LUMO energy level of the organic electron transport layer (such as Bphen, Tmpypb, TPBi, etc.), enabling electrons from the LUMO or conduction band of the first hole injection layer to achieve low-barrier injection and transport to the LUMO or conduction band of the first electron injection layer; at the same time, it is also beneficial to improving the electron mobility and increasing the electron injection and transport rate.

[0025] The first hole injection layer 1093 uses an electron-withdrawing material. Among them, the electron-withdrawing material has a deep HOMO energy level or a deep valence band energy level. The material is one of HAT-CN, MoO3, ZnO, C60, etc., or multiple materials are co-evaporated, or a combined interface layer; the thickness range of the first hole injection layer is 3 nm to 10 nm. When the first hole injection layer material is achieved by co-evaporating multiple materials, the doping ratio of the electron-withdrawing material with a relatively shallow HOMO energy level among HAT-CN, MoO3, ZnO, C60, etc. is 10% to 30%; the function of the first hole injection layer is to absorb the electrons of the hole barrier improvement layer and the second hole injection layer, thereby generating a large number of holes.

[0026] The hole barrier improvement layer 1094 uses an ultra-thin hole injection type dopant, and the material is NiO x, one or more of the materials such as NPD, F4-TCNQ, V2O5, etc., are co-evaporated or a combined interface layer; the thickness range of the hole barrier improvement layer is 1 nm to 5 nm. When the hole barrier improvement layer material is realized by co-evaporation of multiple materials, the doping ratio of the electron-withdrawing material with a relatively shallow HOMO energy level among the materials such as NiOx, NPD, F4-TCNQ, V2O5, etc. is 10% to 30%; the role of the hole barrier improvement layer is to improve the hole injection barrier between the first hole injection layer and the second hole injection layer.

[0027] The second hole injection layer 1095 uses a hole transport layer doped with a hole injection dopant. The hole transport layer has a high HOMO energy level, and the materials are NPB, TAPC, etc.; the hole injection dopant can be one or a combination of multiple materials such as NiOx, NPD, F4-TCNQ, V2O5, etc.; the thickness range of the second hole injection layer is 5 nm to 15 nm, and the proportion of the hole injection dopant is 5% to 15%. The role of the second hole injection layer is to provide a heterojunction interface composed of the first hole injection layer and the hole barrier improvement layer, so that electrons and holes can be effectively generated and separated, and promote the extraction of electrons and the injection and transmission of holes.

[0028] The combination of the first electron injection layer and the second electron injection layer is used to form an improved electron injection barrier interface to promote electron injection and transmission. The combination of the first hole injection layer, the hole barrier improvement layer, and the second hole injection layer is used to form an improved hole injection barrier interface to promote hole injection and transmission.

[0029] As shown in the appendix Figure 1 As shown, this embodiment also discloses a two-color stacked OLED microdisplay, which includes a substrate 001 and two groups of two-color stacked OLED devices located on the substrate 001. Each group of two-color stacked OLED devices includes two different color light-emitting layers. Through the design of the microcavity cavity length, the two groups of two-color stacked OLED devices realize light emission displays of different colors. The structures of the two groups of two-color stacked OLED devices are the same. Each group of two-color stacked OLED devices includes a reflective anode layer 100, an organic layer, and a cathode layer 117 sequentially arranged from bottom to top on the substrate 001; the organic layer includes a first hole injection layer 102, a second hole injection layer 103, a first hole transport layer 104, an electron blocking layer 105, a first light-emitting layer 106, a first hole blocking layer 107, a first electron transport layer 108, a charge generation unit 109, a first hole transport layer 110, an electron blocking layer 111, a second light-emitting layer 112, a second hole blocking layer 113, a second electron transport layer 114, a first electron injection layer 115, and a second electron injection layer 116;

[0030] The first light-emitting layer 106 and the second light-emitting layer 112 adopt light-emitting units of different colors. The thickness range of the first light-emitting layer is 20 nm to 30 nm, and the thickness range of the second light-emitting layer is 20 nm to 30 nm.

[0031] In this embodiment, the substrate 001 is a silicon-based CMOS substrate, also called a silicon-based CMOS driving backplane;

[0032] The cathode layer 117 is a transparent cathode layer or a semi-transparent cathode layer, and its material is a thin metal layer, a metal composite layer or a transparent metal oxide layer. The thickness range is 20 nm to 30 nm; the cathode layer forms a circuit connection with the outside, and there is a thin film encapsulation layer on the cathode layer to block the external environment.

[0033] The reflective anode layer includes several layers of thin films, that is, several layers of reflective metal layers 100 and transparent metal oxide layers 101. The transparent metal oxide is placed above the reflective metal layer to improve the anode reflectivity and work function, as well as the compatibility with the substrate; the material of the reflective metal layer is metal A1 or Ag, and the material of the transparent metal oxide layer is ITO, IZO, MoO3, ZnO, NiO x etc.;

[0034] There are a first pixel area and a second pixel area on the substrate 001. Two groups of dual-color stacked OLED devices respectively correspond to the first pixel area and the second pixel area on the substrate, and the transparent metal oxide layers in the reflective anode layer corresponding to the first pixel area and the second pixel area have different thicknesses, and the thickness is determined according to the cavity length required for the light emitted by the dual-color stacked OLED device. According to the multi-beam interference theory of the Fabry-Perot (F-P) resonator, the interference resonance condition for a certain color light emission display in the microcavity of the dual-color stacked OLED device corresponds to the light wavelength λ, that is, the thickness calculation formula is:

[0035]

[0036] where m is the order of the resonance mode, and are the reflection phase shifts of the two electrodes respectively. The reflection phase shift of the electrode refers to the phase change between the P component and the S component when total reflection occurs at the interface between an optically denser medium and an optically thinner medium. d j and n jare the thickness and refractive index of the j-th layer of the thin film, corresponding to all the thin films between the reflective anode layer and the cathode electrode, and λ is the wavelength of the light emitted by the dual-color stacked OLED device. Through calculation by the formula, with the thickness and refractive index of other thin films being the same, by determining the light rays to be emitted by each group of dual-color stacked OLED devices, the thickness and refractive index of the transparent metal oxide layer are further calculated and determined. In this example, the two light-emitting layers in the dual-color stacked OLED device are a red light-emitting layer and a green light-emitting layer respectively. When a dual-color stacked OLED device is a green light-emitting device, the thickness of the transparent metal oxide layer is 30 nm, and when another dual-color stacked OLED device is a red light-emitting device, the thickness of the transparent metal oxide layer is 85 nm.

[0037] The light-emitting units in the first light-emitting layer and the second light-emitting layer are different and can independently emit light of different colors;

[0038] In the dual-color stacked OLED device of the present invention, the generation, injection, and transport of carriers are realized to achieve high-efficiency light-emitting efficiency of the dual-color device and an extended lifespan of the dual-color device

[0039] This embodiment also discloses a method for manufacturing a dual-color stacked OLED microdisplay, including the following steps:

[0040] S1. Prepare a reflective anode layer on the substrate;

[0041] S2. Deposit an organic layer on the reflective anode layer by vacuum evaporation. The organic layer includes a first hole injection layer 102, a second hole injection layer 103, a first hole transport layer 104, an electron blocking layer 105, a first light-emitting layer 106, a first hole blocking layer 107, a first electron transport layer 108, a charge generation unit 109, a first hole transport layer 110, an electron blocking layer 111, a second light-emitting layer 112, a second hole blocking layer 113, a second electron transport layer 114, a first electron injection layer 115, and a second electron injection layer 116;

[0042] S3. Form a cathode layer 117 on the second electron injection layer 116 by vacuum thermal evaporation or magnetron sputtering; it is transferred to a vacuum thermal evaporation or vacuum magnetron sputtering device through a vacuum evaporator in a vacuum state for production.

[0043] In this embodiment, after S3, a thin film encapsulation operation is further included. A thin film encapsulation layer is deposited on the cathode layer 117. The thin film encapsulation layer is a multi-layer composite thin film, which is fabricated by low-temperature atomic layer deposition and low-temperature plasma-enhanced chemical vapor deposition processes. Specifically, it is one or a combination of AL2O3, TiO2, SiO2, SiON, and SiN. Further, the thickness of the thin film encapsulation layer is between 500 and 5000 nm, and this is preferably selected.

[0044] Further, it also includes the production process of the low-temperature color filter layer and the cover glass bonding layer. Since there are already various publicly available channels for obtaining information on this part, the general practices publicly available in the industry are adopted and will not be elaborated here.

[0045] Embodiment 2

[0046] In this embodiment, in combination with specific selections, a preparation method for a dual-color stacked OLED microdisplay is described as follows:

[0047] 1) Preparation of the reflective anode layer

[0048] A metal Al layer and a transparent metal oxide ITO layer are respectively deposited on the CMOS driving substrate. The overall thicknesses of the reflective anodes corresponding to the first pixel region and the second pixel region are 80 nm and 130 nm respectively.

[0049] 2) Preparation of the organic layer

[0050] The dual-color stacked OLED device of the present invention is fabricated by vacuum evaporation. A hole injection layer 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a first light-emitting layer 106, a hole blocking layer 107, a first electron transport layer 108, a charge generation unit 109, a first hole transport layer 110, an electron blocking layer 111, a second light-emitting layer 112, a hole blocking layer 113, a second electron transport layer 114, an electron injection layer 115, and an electron injection layer 116 are sequentially deposited above the reflective anode.

[0051] Among them, the first light-emitting layer and the second light-emitting layer are a green phosphorescent light-emitting material and a red phosphorescent light-emitting material respectively. The thickness of the first light-emitting layer is 30 nm, and the thickness of the second light-emitting layer is 30 nm. In the charge generation unit, the thickness range of the first electron injection layer is 5 nm to 15 nm, and the thickness range of the second electron injection layer is 5 nm to 15 nm. The superimposed thickness of the first electron injection layer and the second electron injection layer is less than 20 nm, and the doping material ratio of the electron injection layer is 10% to 30%; the thickness of the first hole injection layer is 3 nm to 10 nm, the hole injection dopant ratio is 5% to 15%, the thickness of the hole barrier improvement layer is 1 nm to 5 nm, and the thickness of the second hole injection layer is 5 nm to 15 nm. The thicknesses of other layers are set according to the requirements of the OLED device and will not be elaborated here.

[0052] 3) Preparation of the cathode layer

[0053] The transparent cathode layer of this embodiment is fabricated by vacuum thermal evaporation or magnetron sputtering. In a vacuum state, it is transferred to a vacuum thermal evaporation or vacuum magnetron sputtering device through a vacuum evaporation machine. Specifically, it is a thin metal layer, a metal composite layer, or a transparent metal oxide layer with a thickness of 20 nm;

[0054] 4) Preparation of composite thin film encapsulation layer

[0055] The thin film encapsulation layer of the present invention is a multi-layer composite thin film, which is fabricated by low-temperature atomic layer deposition and low-temperature plasma-enhanced chemical vapor deposition processes. Specifically, it is one or a combination of AL2O3, TiO2, SiO2, SiON, and SiN. Further, the thickness of the thin film encapsulation layer is between 500 and 5000 nm, and the preferred value is selected.

[0056] 5) Preparation of red and green dual-color microdisplays

[0057] Further, it also includes the production processes of a low-temperature color filter layer and a cover glass bonding layer. Since there are already multiple publicly available channels for obtaining information in this part, the general practices publicly available in the industry are adopted and will not be elaborated here.

[0058] Thus, the manufacturing process of the above-mentioned dual-color stacked microcavity OLED device is completed.

[0059] Figure 3 The structures of the red and green dual-color stacked OLED devices and the normalized red and green monochromatic emission spectra are respectively shown. It can be seen that through microcavity regulation, the dual-color stacked OLED device can emit relatively pure red and green monochromatic lights respectively.

[0060] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A charge generation unit, characterized in that, It includes a first electron injection layer, a second electron injection layer, a first hole injection layer, a hole barrier improvement layer, and a second hole injection layer, which are sequentially arranged from top to bottom; The first electron injection layer is doped with a low work function rare earth metal or a highly conductive metal using an alkali metal compound material; the second electron injection layer is doped with a low work function rare earth metal or a highly conductive metal using an organic electron transport layer material; the first hole injection layer uses an electron-withdrawing material, and the electron-withdrawing material has a deep HOMO energy level or a deep valence band energy level; the hole barrier improvement layer uses an ultra-thin hole injection type dopant; the second hole injection layer uses a hole transport layer doped with a hole injection dopant, and the hole transport layer has a high HOMO energy level.

2. The charge generation unit according to claim 1, wherein: In the first electron injection layer, the alkali metal compound material is LiF, CS2CO3, Liq or Ru2CO3; the highly conductive metal is Li, Ag, Au or Al; In the second electron injection layer, the organic electron transport layer material is Bphen, Tmpypb or TPBi.

3. The charge generation unit according to claim 1, wherein: The thickness range of the first electron injection layer is 5nm to 15nm, and the thickness range of the second electron injection layer is 5nm to 15nm, wherein the stacked thickness of the first electron injection layer and the second electron injection layer is less than 20nm.

4. The charge generation unit according to claim 1, wherein: The material of the first hole injection layer is one of HAT-CN, MoO3, ZnO, C60, or co-evaporation of multiple ones, or a combined interface layer; the thickness range of the first hole injection layer is 3nm to 10nm.

5. The charge generation unit according to claim 1, characterized in that: The hole barrier improvement layer material is NiO x , one of the materials of NPD, F4-TCNQ, V2O5, or co-evaporation of multiple materials, or a combined interface layer; the thickness range of the hole barrier improvement layer is 1 nm to 5 nm.

6. A dual-color stacked OLED microdisplay, characterized in that, It includes a substrate and two sets of dual-color stacked OLED devices located on the substrate. The structures of the two sets of dual-color stacked OLED devices are the same, and include a reflective anode layer, an organic layer, and a cathode layer, which are sequentially arranged from bottom to top on the substrate; the organic layer includes a first hole injection layer, a second hole injection layer, a first hole transport layer, an electron blocking layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, a charge generation unit, a first hole transport layer, an electron blocking layer, a second light-emitting layer, a second hole blocking layer, a second electron transport layer, a first electron injection layer, and a second electron injection layer; the charge generation unit is a charge generation unit according to any one of claims 1-5; The first light-emitting layer and the second light-emitting layer use light-emitting units of different colors, and the microcavity cavity lengths of the two sets of dual-color stacked OLED devices are different, so as to realize different color light-emitting displays of the two sets of dual-color stacked OLED devices.

7. A dual-color stacked OLED microdisplay according to claim 6, characterized in that: There are a first pixel area and a second pixel area on the substrate. The two sets of dual-color stacked OLED devices respectively correspond to the first pixel area and the second pixel area on the substrate, and the transparent metal oxide layers in the reflective anode layer corresponding to the first pixel area and the second pixel area have different thicknesses, and the thicknesses are determined according to the cavity lengths required for the light-emitting rays in the dual-color stacked OLED devices.

8. A dual-color stacked OLED microdisplay according to claim 7, characterized in that: The thickness calculation formula is: where m is the order of the resonance mode, and are the reflection phase shifts of the two electrodes, respectively, d j and n j are the thickness and refractive index of the j-th layer thin film between the reflective anode layer and the cathode electrode, respectively, and λ is the emission light wavelength of the two-color stacked OLED device.

9. The manufacturing method of a two-color stacked OLED microdisplay according to claim 6, wherein It includes the following steps: S1. Prepare a reflective anode layer on a silicon-based CMOS substrate; S2. Deposit an organic layer on the reflective anode layer by means of vacuum evaporation. The organic layer includes a first hole injection layer, a second hole injection layer, a first hole transport layer, an electron blocking layer, a first light-emitting layer, a first hole blocking layer, a first electron transport layer, a charge generation unit, a first hole transport layer, an electron blocking layer, a second light-emitting layer, a second hole blocking layer, a second electron transport layer, a first electron injection layer, and a second electron injection layer; S3. Form a cathode layer on the second electron injection layer by means of vacuum thermal evaporation or magnetron sputtering.

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