Silicon-based OLED (Organic Light Emitting Diode) micro display

Abstract

The invention relates to the technical field of silicon-based OLED micro-displays, and discloses a silicon-based OLED micro-display, which comprises a silicon-based backboard, an organic light-emitting layer and a packaging layer, a double-layer blue light-emitting layer and a buffer layer are arranged in the organic light-emitting layer, a blue light-emitting material in the double-layer blue light-emitting layer is doped with rare earth elements, and the buffer layer is doped with rare earth elements. A thin film packaging material layer in the packaging layer is formed by an inorganic material and an organic material through an alternate deposition method, the silicon-based backboard is used for bearing and integrating a driving circuit, the organic light-emitting layer is used for realizing image display under current driving, and the packaging layer is used for protecting the organic light-emitting layer and blocking water and oxygen. According to the OLED material and the preparation method thereof, a reasonable energy transfer and charge distribution mechanism can be formed between the blue light-emitting layers through the double blue light-emitting layers, so that the problem that the service life is shortened due to the fact that the molecular structure of the blue light-emitting material in a traditional OLED material is relatively unstable is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon-based OLED microdisplays, and in particular to a silicon-based OLED microdisplay. Background Art

[0002] OLED microdisplay is an advanced display technology. OLED stands for organic light-emitting diode, and microdisplay refers to a display with a smaller size. Structurally, it emits light by coating an organic material on a substrate material. This display has the characteristics of self-luminescence, does not require a backlight, and can be made thinner than traditional LCDs. Its pixels can independently control light emission, which enables it to present deep blacks and extremely high contrast, brighter and more vivid colors, and a very wide viewing angle, with clear images from almost every angle. In the application field, OLED microdisplays play a key role in virtual reality (VR) and augmented reality (AR) devices. Because of its high resolution and small size, it can provide a clear visual experience in compact head-mounted devices. At the same time, it is also widely used in some high-end electronic viewfinders, micro projectors and other devices. It can display high-quality images in a small space, promoting the progress of these devices in terms of performance and portability.

[0003] The molecular structure of the blue light-emitting material in traditional OLED materials is relatively unstable. During the passage of current and long-term use, the chemical bonds within the molecules are easily broken or rearranged, resulting in a decrease in the luminescence performance of the material, which in turn leads to a shortened lifespan. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a silicon-based OLED microdisplay, which solves the problem that the molecular structure of the blue light-emitting material in traditional OLED materials is relatively unstable. During the passage of current and long-term use, the chemical bonds within the molecules are easily broken or rearranged, resulting in a decrease in the luminescent performance of the material and a subsequent reduction in lifespan.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a silicon-based OLED microdisplay, comprising a silicon-based backplane, an organic light-emitting layer and an encapsulation layer, wherein a double-layer blue light-emitting layer and a buffer layer are arranged in the organic light-emitting layer, the blue light-emitting material in the double-layer blue light-emitting layer is doped with rare earth elements, the thin film encapsulation material layer in the encapsulation layer is formed by alternating deposition of inorganic materials and organic materials, the silicon-based backplane is used to carry and integrate a driving circuit, the organic light-emitting layer is used to realize image display under current drive, and the encapsulation layer is used to protect the organic light-emitting layer and block water and oxygen.

[0006] Preferably, the silicon-based backplane includes a single-crystal silicon substrate, a CMOS driving circuit, a metal interconnection layer and a passivation layer, wherein the single-crystal silicon substrate is used to provide a physical support platform for the circuits and devices in the silicon-based OLED microdisplay, the CMOS driving circuit is used to accurately control the light-emitting state of each pixel in the silicon-based OLED microdisplay, the metal interconnection layer is used to connect different circuit elements and regions on the silicon-based backplane of the silicon-based OLED microdisplay, and the passivation layer is used to protect the circuit elements on the silicon-based backplane.

[0007] Preferably, the organic light-emitting layer also includes an anode, a hole transport layer, an electron transport layer and a cathode, the anode is used to inject holes, the hole transport layer is used to transport holes injected from the anode to the light-emitting layer, the cathode is used to inject electrons, and the electron transport layer is used to transport electrons from the cathode to the light-emitting layer.

[0008] Preferably, the encapsulation layer further comprises a sealant layer and a glass cover plate, wherein the glass cover plate is used to provide physical protection for the silicon-based OLED microdisplay, and the sealant layer is used to tightly fit the thin-film encapsulation material layer to the glass cover plate.

[0009] Preferably, the blue light-emitting material is 9,10-di(2-naphthyl)anthracene, the rare earth element is terbium trifluoromethanesulfonate, the weight ratio of 9,10-di(2-naphthyl)anthracene to terbium trifluoromethanesulfonate is 95-99:0.1-5, and the rare earth element is doped by a solution method.

[0010] Preferably, the buffer layer is located between the hole transport layer and the blue light-emitting material, the buffer layer material is tris(4-carbazol-9-ylphenyl)amine (TCTA), and the thickness is controlled to be 5-15 nanometers.

[0011] Preferably, the inorganic material in the thin film encapsulation material layer is silicon nitride, the organic material is polyparaxylene, and the weight ratio of silicon nitride to polyparaxylene is 40-60:45-65.

[0012] Preferably, the alternating deposition method is to first deposit a layer of 50-100 nanometers thick silicon nitride by PECVD, and then spin-coat a layer of 100-200 nanometers thick polyparaxylene by solution, and perform the process alternately 3-5 times.

[0013] The present invention provides a silicon-based OLED microdisplay having the following beneficial effects:

[0014] 1. In the present invention, a double-layer blue light-emitting layer can provide a reasonable energy transfer and charge distribution mechanism between each blue light-emitting layer. When the OLED device is working, the total current flowing through the blue light-emitting area can be dispersed, the current density borne by each blue light-emitting layer can be reduced, the material aging problem caused by high current density can be reduced, and the overall service life of the blue light-emitting material can be extended, thereby improving the relatively unstable molecular structure of the blue light-emitting material in the traditional OLED material. During the passage of current and long-term use, the chemical bonds within the molecules are easily broken or rearranged, resulting in a decrease in the luminescence performance of the material, and then resulting in a reduced service life.

[0015] 2. In the present invention, rare earth elements are doped into the main blue light-emitting organic material. The rare earth elements realize energy transfer and exciton stabilization during the current flow and light emission process through their special electronic structure, so as to reduce energy loss, delay material aging, and thus improve the luminous efficiency and stability, and enhance the service life of the blue light-emitting material in the OLED device.

[0016] 3. In the present invention, a buffer layer is provided between the blue light-emitting layer and the adjacent hole transport layer. The buffer layer material can regulate the rate and quantity of holes and electrons injected into the blue light-emitting layer, so that the holes and electrons injected into the blue light-emitting layer reach a more matched state, thereby reducing the damage to the blue light-emitting material caused by charge accumulation and extending the life of the blue light-emitting material in the OLED device.

[0017] 4. In the present invention, silicon nitride and polyparaxylene are used in the thin film encapsulation material layer through alternating deposition. Silicon nitride provides water and oxygen barrier function, and polyparaxylene plays a role of buffering stress to prevent cracks in the inorganic layer. Through the synergistic effect of this multi-layer structure, it can effectively block external water and oxygen from entering the interior of the OLED device, protect the blue light-emitting material, and extend the service life of the OLED device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural block diagram of the present invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Please refer to the attached Figure 1An embodiment of the present invention provides a silicon-based OLED microdisplay, characterized in that it includes a silicon-based backplane, an organic light-emitting layer and an encapsulation layer, a double-layer blue light-emitting layer and a buffer layer are arranged in the organic light-emitting layer, the blue light-emitting material in the double-layer blue light-emitting layer is doped with rare earth elements, and the thin film encapsulation material layer in the encapsulation layer is formed by alternating deposition of inorganic materials and organic materials. The silicon-based backplane is used to carry and integrate a driving circuit, the organic light-emitting layer is used to realize image display under current drive, and the encapsulation layer is used to protect the organic light-emitting layer and block water and oxygen.

[0021] Specifically, the silicon-based backplane can provide a solid physical support for the silicon-based OLED microdisplay, integrate a driving circuit to accurately control pixel light emission, ensure signal transmission, and improve device performance and stability. The organic light-emitting layer can be driven by current to allow electrons and holes to combine and undergo energy transition, thereby generating visible light and realizing the light-emitting function of image display. The organic light-emitting layer also includes a red light-emitting layer, a green light-emitting layer, and a white light-emitting layer. The encapsulation layer can effectively block external harmful factors such as water, oxygen, and dust, protect the internal device structure, ensure the stable performance of the silicon-based OLED microdisplay, and extend its service life. The double-layer blue light-emitting layer can improve the blue light-emitting efficiency and enhance the blue light-emitting intensity, and help adjust the spectral characteristics of the blue light emission, thereby improving the color purity of the blue light. And color stability, thereby improving the display quality of silicon-based OLED microdisplays; the buffer layer can effectively relieve the stress caused by the difference in thermal expansion coefficients of different materials or external mechanical stress, and at the same time can improve the interface characteristics, improve the charge injection and transmission efficiency, thereby improving the stability and performance of the device; the blue luminescent material doped with rare earth elements can effectively improve the luminous efficiency and color purity, and can also enhance the luminous stability and adjust the luminous spectrum, thereby improving the quality of blue display of silicon-based OLED microdisplays; the thin-film encapsulation material layer is formed by alternating deposition of inorganic materials and organic materials to effectively combine the high barrier properties of inorganic materials and the flexibility and buffering properties of organic materials, significantly improving the barrier effect against harmful factors such as water vapor and oxygen, enhancing the packaging stability, and extending the service life of the device.

[0022] The silicon-based backplane includes a single-crystal silicon substrate, a CMOS driving circuit, a metal interconnection layer and a passivation layer. The single-crystal silicon substrate is used to provide a physical support platform for the circuits and devices in the silicon-based OLED microdisplay. The CMOS driving circuit is used to accurately control the light-emitting state of each pixel in the silicon-based OLED microdisplay. The metal interconnection layer is used to connect different circuit elements and areas on the silicon-based backplane of the silicon-based OLED microdisplay. The passivation layer is used to protect the circuit elements on the silicon-based backplane.

[0023] Specifically, the single-crystal silicon substrate can ensure the integrity of the device structure, serve as a good heat conduction medium, and facilitate high-precision micro-nano processing, thereby improving the performance and manufacturing accuracy of the display. The CMOS driving circuit can accurately control whether each pixel in the silicon-based OLED microdisplay emits light and the luminous intensity, thereby achieving fast and efficient signal conversion and transmission, thereby ensuring high-quality, high-resolution image display. The metal interconnection layer can achieve electrical connection between various components (such as pixel electrodes, driving circuits, etc.) in the silicon-based OLED microdisplay, effectively transmit electrical signals, ensure the integrity and stability of the signal, thereby ensuring the normal operation and performance of the display. The passivation layer can protect the active layer and metal interconnection structures in the silicon-based OLED microdisplay to prevent them from being corroded by water vapor and chemicals and mechanical scratches, while reducing surface charge accumulation and improving the stability and reliability of the device.

[0024] The organic light-emitting layer also includes an anode, a hole transport layer, an electron transport layer and a cathode. The anode is used to inject holes, the hole transport layer is used to transport the holes injected from the anode to the light-emitting layer, the cathode is used to inject electrons, and the electron transport layer is used to transport electrons from the cathode to the light-emitting layer.

[0025] Specifically, the anode can effectively receive holes and inject them into the organic light-emitting layer, and at the same time collect current and connect to the external circuit, which is an indispensable part of realizing the light-emitting process. The hole transport layer can promote the effective transmission of holes injected from the anode to the organic light-emitting layer, adjust the hole injection efficiency, and balance the charge distribution in the light-emitting layer, thereby improving the luminous efficiency and performance of the device. The electron transport layer can smoothly transmit electrons from the cathode to the organic light-emitting layer, and effectively block holes, helping to achieve more efficient recombination of electrons and holes in the light-emitting layer, thereby improving the luminous efficiency and brightness uniformity of the silicon-based OLED microdisplay. The cathode can effectively inject electrons and recombine with holes injected from the anode and transmitted through the hole transport layer in the organic light-emitting layer, thereby triggering the light-emitting process, and plays a role in connecting to the external circuit to form a complete circuit loop.

[0026] The encapsulation layer also includes a sealant layer and a glass cover plate. The glass cover plate is used to provide physical protection for the silicon-based OLED microdisplay, and the sealant layer is used to tightly fit the thin-film encapsulation material layer to the glass cover plate.

[0027] Specifically, the sealant layer can form a sealing structure at the edge of the silicon-based OLED microdisplay to prevent harmful substances such as external water vapor, oxygen, and dust from entering the interior of the display. The auxiliary packaging layer can enhance the overall sealing performance and ensure the stability and service life of the display. The glass cover can provide physical protection for the silicon-based OLED microdisplay to prevent it from external mechanical damage and scratches. At the same time, it can block pollutants such as dust and water vapor, and can reduce external light interference to a certain extent, thereby improving the display effect.

[0028] The blue luminescent material is 9,10-di(2-naphthyl)anthracene, the rare earth element is terbium trifluoromethanesulfonate, the weight ratio of 9,10-di(2-naphthyl)anthracene to terbium trifluoromethanesulfonate is 95-99:0.1-5, and the rare earth element is doped by a solution method.

[0029] Specifically, the blue light-emitting material is 9,10-di(2-naphthyl)anthracene, which can emit blue fluorescence with a wavelength of 435-445nm and has a high fluorescence quantum yield, can effectively realize blue light emission, and provide a high-quality blue light source for silicon-based OLED microdisplays. The rare earth element is terbium trifluoromethanesulfonate, which can play a role in fine-tuning the light-emitting performance, and improve the light-emitting efficiency by energy transfer or changing the electronic structure of the main material.

[0030] The buffer layer is located between the hole transport layer and the blue light-emitting material. The material of the buffer layer is tris(4-carbazole-9-ylphenyl)amine (TCTA), and the thickness is controlled at 5-15 nanometers.

[0031] Specifically, by locating the buffer layer between the hole transport layer and the blue light-emitting material, the injection rate and number of holes can be adjusted, the energy loss and charge accumulation at the interface can be reduced, and the charge injection balance between holes and the light-emitting material can be optimized, thereby improving the luminescence efficiency and stability of the silicon-based OLED microdisplay. By using tris(4-carbazol-9-ylphenyl)amine (TCTA) as the buffer layer material, the injection efficiency of holes from the hole transport layer to the blue light-emitting material can be effectively improved, the charge transfer can be balanced, and interface traps can be reduced, thereby improving the luminescence performance and stability of the silicon-based OLED microdisplay. By controlling the thickness to 5-15 nanometers, while ensuring effective regulation of charge injection and transfer, it is possible to avoid an increase in resistance and a prolonged response time due to excessive thickness, or an inability to fully exert the buffering effect due to excessive thinness, thereby optimizing the performance of the silicon-based OLED microdisplay.

[0032] The inorganic material in the thin film packaging material layer is silicon nitride, the organic material is poly-p-xylene, and the weight ratio of silicon nitride to poly-p-xylene is 40-60:45-65.

[0033] Specifically, by using silicon nitride as the inorganic material in the thin-film encapsulation material layer, it can effectively protect the internal device structure with its excellent gas barrier properties (good barrier effect on water vapor and oxygen), and improve the stability and service life of the silicon-based OLED microdisplay; by using polyparaxylene as the organic material, it can provide good flexibility and cushioning properties, cover the tiny unevenness on the device surface, assist the inorganic material in enhancing the barrier effect of the overall package, and improve the mechanical stress resistance and moisture resistance of the silicon-based OLED microdisplay; by using a weight ratio of silicon nitride to polyparaxylene of 40-60:45-65, a good balance between the high barrier properties of the inorganic material and the flexibility of the organic material can be achieved in the thin-film encapsulation material layer, effectively improving the packaging quality of the silicon-based OLED microdisplay, and enhancing its comprehensive performance against water vapor, oxygen penetration and mechanical damage.

[0034] The alternating deposition method is to first deposit a layer of 50-100 nanometers thick silicon nitride by PECVD, and then spin-coat a layer of 100-200 nanometers thick polyparaxylene from the solution, alternating for 3-5 times.

[0035] Specifically, through this alternating deposition method, the excellent gas barrier properties of silicon nitride and the good flexibility and flatness of polyparaxylene can be fully combined to form a multi-layer composite packaging structure, which can effectively block the invasion of harmful substances such as water vapor and oxygen, and greatly enhance the stability, reliability and damage resistance of silicon-based OLED microdisplay packaging.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A silicon-based OLED micro display, comprising a silicon-based backplane, an organic light-emitting layer and an encapsulation layer, characterized in that: A double-layer blue light-emitting layer and a buffer layer are arranged in the organic light-emitting layer, the blue light-emitting material in the double-layer blue light-emitting layer is doped with rare earth elements, the thin-film encapsulation material layer in the encapsulation layer is formed by alternating deposition of inorganic materials and organic materials, the silicon-based backplane is used to carry and integrate the driving circuit, the organic light-emitting layer is used to realize image display under current drive, and the encapsulation layer is used to protect the organic light-emitting layer and block water and oxygen.

2. A silicon-based OLED microdisplay according to claim 1, characterized in that: The silicon-based backplane includes a single-crystal silicon substrate, a CMOS driving circuit, a metal interconnection layer and a passivation layer. The single-crystal silicon substrate is used to provide a physical support platform for the circuits and devices in the silicon-based OLED microdisplay. The CMOS driving circuit is used to accurately control the light-emitting state of each pixel in the silicon-based OLED microdisplay. The metal interconnection layer is used to connect different circuit elements and regions on the silicon-based backplane of the silicon-based OLED microdisplay. The passivation layer is used to protect the circuit elements on the silicon-based backplane.

3. The silicon-based OLED microdisplay according to claim 1, characterized in that: The organic light-emitting layer also includes an anode, a hole transport layer, an electron transport layer and a cathode. The anode is used to inject holes, the hole transport layer is used to transport holes injected from the anode to the light-emitting layer, the cathode is used to inject electrons, and the electron transport layer is used to transport electrons from the cathode to the light-emitting layer.

4. The silicon-based OLED microdisplay according to claim 1, characterized in that: The encapsulation layer also includes a sealant layer and a glass cover plate. The glass cover plate is used to provide physical protection for the silicon-based OLED microdisplay, and the sealant layer is used to tightly fit the thin-film encapsulation material layer to the glass cover plate.

5. The silicon-based OLED microdisplay according to claim 1, characterized in that: The blue luminescent material is 9,10-di(2-naphthyl)anthracene, the rare earth element is terbium trifluoromethanesulfonate, the weight ratio of 9,10-di(2-naphthyl)anthracene to terbium trifluoromethanesulfonate is 95-99:0.1-5, and the rare earth element is doped by a solution method.

6. The silicon-based OLED microdisplay according to claim 1, characterized in that: The buffer layer is located between the hole transport layer and the blue light-emitting material. The material of the buffer layer is tris(4-carbazole-9-ylphenyl)amine (TCTA), and the thickness is controlled at 5-15 nanometers.

7. The silicon-based OLED microdisplay according to claim 1, characterized in that: The inorganic material in the thin film packaging material layer is silicon nitride, the organic material is polyparaxylene, and the weight ratio of silicon nitride to polyparaxylene is 40-60:45-65.

8. The silicon-based OLED microdisplay according to claim 1, characterized in that: The alternating deposition method is to first deposit a layer of silicon nitride with a thickness of 50-100 nanometers by PECVD, and then spin-coat a layer of polyparaxylene with a thickness of 100-200 nanometers by solution, and the process is performed alternately for 3-5 times.

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