A micro display device and a method for manufacturing the same

Abstract

The present invention discloses a micro display device and a preparation method thereof, which relates to the field of display technology, wherein the micro display device comprises: a driving substrate; a pixel array layer, comprising a plurality of micro display units, arranged on the surface of the driving substrate; a nano composite film, comprising a multi-layer nano-scale film layer, located in the light emitting direction of the side wall of the micro display unit; wherein the multi-layer nano-scale film layer comprises an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall. The technical solution provided by the present invention not only enhances the optical isolation and electrical isolation between the micro display units, but also meets the demand for preparing micro display units of smaller size.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of display technology, and in particular to a micro display device and a method for preparing the same. Background Art

[0002] With the rapid development of display technology, MicroLED (micro light emitting diode), as the next generation display technology, has attracted widespread attention due to its advantages such as high brightness, high contrast, low power consumption and long life.

[0003] In high-density arrayed MicroLED displays, optical crosstalk and electrical interference are prone to occur between microdisplay units. Optical crosstalk refers to the phenomenon that the light emitted by MicroLED pixels enters adjacent pixels through side scattering or propagation through the substrate, resulting in color confusion, reduced light intensity, etc. In order to solve this problem, optical isolation structures such as reflective cups or vinyl isolation materials are traditionally used to limit the diffusion of light. However, these methods have the challenges of low reflection efficiency and difficulty in adapting to smaller pixels, and cannot improve the problem of electrical signal interference caused by electric field interference between electrodes, which in turn affects the normal operation of MicroLED; therefore, how to enhance the optical isolation and electrical isolation between microdisplay units while meeting the needs of adapting to the preparation of smaller microdisplay units has become a technical problem that people in this field need to solve urgently. Summary of the invention

[0004] The embodiment of the present invention provides a micro display device and a method for manufacturing the same, so as to enhance the optical isolation and electrical isolation between micro display units while meeting the demand for preparing micro display units with smaller sizes.

[0005] According to one aspect of the present invention, there is provided a micro display device, comprising:

[0006] Driver substrate;

[0007] A pixel array layer, comprising a plurality of micro display units, arranged on the surface of the driving substrate;

[0008] The nanocomposite film comprises a multi-layer nanoscale film layer, which is located in the light emitting direction of the side wall of the micro display unit; wherein the multi-layer nanoscale film layer comprises an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall.

[0009] Optionally, the material of the insulating bottom layer includes silicon oxide; the material of the intermediate transmission layer includes tantalum pentoxide; the material of the reflective layer includes aluminum oxide; and the material of the protective layer includes polymethyl methacrylate.

[0010] Optionally, the pixel array layer further includes:

[0011] A light emitting structure layer is located on the surface of the driving substrate; the light emitting structure layer includes a plurality of light emitting structures arranged at intervals;

[0012] A first dielectric layer is located on a side of the light emitting structure away from the driving substrate and between two adjacent light emitting structures; wherein a surface of the dielectric layer away from the driving substrate includes a plurality of first grooves corresponding to the light emitting structures;

[0013] A color conversion layer, comprising a plurality of color conversion units, each of the color conversion units being located in a corresponding first groove;

[0014] The micro display unit includes a light emitting structure and a color conversion unit corresponding to the light emitting structure; the nano composite film is located in the light emitting direction of the side wall of the color conversion unit.

[0015] Optionally, the nanocomposite film is located on the side wall of the color conversion unit; the multi-layer nanoscale film layer includes an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protection layer which are sequentially away from the side wall of the color conversion unit.

[0016] And / or, the surface of the first dielectric layer away from the driving substrate also includes a plurality of second grooves, and the second grooves are located between two adjacent first grooves; the nano-composite film is located on the sidewalls and bottom surfaces of the second grooves; and the multi-layer nano-scale film layer includes an insulating bottom layer, an intermediate transmission layer, a reflective layer and a protective layer which are sequentially away from the second grooves.

[0017] Optionally, the second groove is arranged around the micro display unit;

[0018] And / or, the distance from the bottom surface of the second groove to the driving substrate is less than or equal to the distance from the surface of the light emitting structure away from the driving substrate to the driving substrate.

[0019] Optionally, the outer surface of the nanocomposite film includes a microstructure, and the microstructure is used to reduce the amount of light emitted from the side wall of the microdisplay unit;

[0020] Wherein, the microstructure includes at least one of a nano pattern, a nano hole array and a nano column array.

[0021] Optionally, the light emitting structure includes:

[0022] A first semiconductor layer, located on one side of the driving substrate;

[0023] a light emitting layer, located on a side of the first semiconductor layer away from the driving substrate;

[0024] A second semiconductor layer is located on a side of the light emitting layer away from the driving substrate;

[0025] A current spreading layer is provided on at least one of a side of the first semiconductor layer facing the driving substrate and a side of the second semiconductor layer away from the driving substrate;

[0026] The surface of the driving substrate close to the pixel array layer includes a first driving electrode and a second driving electrode, the first semiconductor layer is electrically connected to the first driving electrode, and the second semiconductor layer is electrically connected to the second driving electrode.

[0027] Optionally, the micro display device further includes:

[0028] a second dielectric layer located on a side wall of the light emitting structure, a surface of the light emitting structure away from the driving substrate, and a surface of the driving substrate not covered by the light emitting structure; wherein the second dielectric layer located on a side of the light emitting structure away from the driving substrate comprises an electrode opening, and the electrode opening exposes a second semiconductor layer or a current spreading layer of the light emitting structure;

[0029] The electrode lead is located between the first dielectric layer and the second dielectric layer, and the electrode lead is electrically connected to the second semiconductor layer or the current spreading layer through the electrode opening.

[0030] According to another aspect of the present invention, a method for preparing a micro display device is provided, which is used to prepare the micro display device according to any embodiment of the present invention, comprising:

[0031] Providing a drive substrate;

[0032] A pixel array layer is formed on one side of the driving substrate; the pixel array includes a plurality of micro display units arranged on a surface of the driving substrate;

[0033] A nanocomposite film is formed, which includes a plurality of nanoscale film layers and is located in the light emitting direction of the side wall of the microdisplay unit; wherein the plurality of nanoscale film layers include an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall.

[0034] Optionally, forming a pixel array layer on one side of the driving substrate includes:

[0035] forming a light-emitting structure layer on the surface of the driving substrate, wherein the light-emitting structure layer includes a plurality of light-emitting structures arranged at intervals;

[0036] A first dielectric layer is formed on a side of the light emitting structure away from the driving substrate and between two adjacent light emitting structures, and a plurality of first grooves corresponding to the light emitting structures are formed on a surface of the first dielectric layer away from the driving substrate;

[0037] A color conversion layer is formed on a side of the first dielectric layer away from the driving substrate, wherein the color conversion layer has a plurality of color conversion units, and each of the color conversion units is correspondingly located in one of the first grooves;

[0038] The forming of the nanocomposite film comprises:

[0039] Spin coating a protective layer on the sidewall of the first trench;

[0040] Forming a reflective layer, an intermediate transmission layer and an insulating bottom layer in sequence on the surface of the protective layer by an atomic deposition process;

[0041] Alternatively, the forming of the nanocomposite film comprises:

[0042] A plurality of second grooves are formed on a surface of the first dielectric layer away from the driving substrate, wherein the second grooves are located between two adjacent first grooves;

[0043] forming an insulating bottom layer, an intermediate transmission layer and a reflective layer in sequence on the sidewall and bottom of the second trench by an atomic deposition process;

[0044] A protective layer is spin-coated on the surface of the reflective layer.

[0045] The embodiment of the present invention provides a micro display device and a preparation method thereof, wherein the micro display device comprises: a driving substrate; a pixel array layer, comprising a plurality of micro display units; a surface nano composite film arranged on the driving substrate, comprising a multi-layer nano-scale film layer, located in the light emitting direction of the side wall of the micro display unit; wherein the multi-layer nano-scale film layer comprises an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall. The technical solution provided by the embodiment of the present invention applies the nano-scale film layer to the optical isolation and electrical isolation of the micro display unit; by introducing a nano-composite film comprising an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer between the micro display units, it can not only effectively prevent the propagation of photons between pixels, improve the reflection efficiency of the side wall of the micro display unit, and improve the light emitting amount of the micro display unit, but also has an excellent electrical isolation effect, and the thickness of the nano-scale film layer can be precisely controlled by the atomic layer deposition process to realize the electrical isolation function, so as to meet the needs of preparing a micro display unit of smaller size, and at the same time, each film layer in the nano-composite film adopts a material compatible with the manufacturing material of the micro display unit, which is easy to integrate and process.

[0046] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 is a schematic structural diagram of a micro display device provided by an embodiment of the present invention;

[0049] Figure 2 is a schematic structural diagram of another micro display device provided by an embodiment of the present invention;

[0050] Figure 3 yes Figure 2 Schematic diagram of the structure of the nanocomposite membrane in the structure shown;

[0051] Figure 4 is a schematic structural diagram of another micro display device provided by an embodiment of the present invention;

[0052] Figure 5 yes Figure 4 Schematic diagram of the structure of the nanocomposite membrane in the structure shown;

[0053] Figure 6 is a flow chart of a method for preparing a micro display device provided by an embodiment of the present invention;

[0054] Figure 7 is a schematic cross-sectional structure diagram of a driving substrate provided in a method for preparing a micro display device provided in an embodiment of the present invention;

[0055] Figure 8 It is a schematic cross-sectional structure diagram after electrode leads are formed on a side of a second dielectric layer away from a driving substrate in a method for preparing a micro display device provided by an embodiment of the present invention;

[0056] Fig. 9 A schematic cross-sectional structure diagram of a method for preparing a micro display device provided by an embodiment of the present invention after a first dielectric layer is formed on a side of a light emitting structure away from a driving substrate and between two adjacent light emitting structures;

[0057] Fig.10 A schematic cross-sectional structure diagram of a method for preparing a micro display device provided by an embodiment of the present invention after a plurality of first grooves corresponding to the light-emitting structure are formed on a surface of a first dielectric layer away from a driving substrate;

[0058] Fig.11 It is a schematic diagram of the cross-sectional structure after a nanocomposite film is formed on the side wall of the first groove in a method for preparing a micro display device provided by an embodiment of the present invention;

[0059] Fig.12 It is a schematic diagram of the cross-sectional structure after a second groove is formed on the surface of a first dielectric layer in a method for preparing a micro display device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0061] An embodiment of the present invention provides a micro display device, Figure 1 is a schematic diagram of a micro display device provided by an embodiment of the present invention, with reference to Figure 1 , the micro display device comprises:

[0062] A driving substrate 10;

[0063] The pixel array layer 20 includes a plurality of micro display units 201 arranged on the surface of the driving substrate 10;

[0064] The nanocomposite film 30 includes multiple nano-scale film layers, which are located in the light-emitting direction of the side wall of the micro display unit 201; wherein the multiple nano-scale film layers include an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protection layer which are sequentially away from the side wall.

[0065] Specifically, the micro display unit 201 is arranged on the surface of the driving substrate 10, and the driving substrate 10 is used to provide a driving signal to the micro display unit 201 to drive the micro display unit 201 to emit light. The driving substrate 10 is usually a printed circuit board with a CMOS driving circuit configured on the surface, and the circuit configured on the surface is designed according to specific application requirements. The nano-composite film 30 includes a multi-layer nano-scale film layer, and the nano-scale film layer refers to a film layer structure with a thickness in the nanoscale range. Introducing a nano-scale film layer as a photoelectric isolation film layer between the micro display units 201 can be more suitable for micro-display units 201 of small size. The material of the nano-composite film 30 adopts a material compatible with the manufacturing material of the micro display unit 201, so that the nano-composite film 30 is easy to integrate and process.

[0066] Among them, the multi-layer nano-scale film layer includes an insulating bottom layer, an intermediate transmission layer, a reflective layer and a protective layer which are stacked. The nano-composite film 30 is arranged in the light-emitting direction of the side wall of the micro-display unit 201. The light emitted from the side wall of the micro-display unit 201 first reaches the insulating bottom layer, the light passing through the insulating bottom layer reaches the intermediate transmission layer, the light passing through the intermediate transmission layer reaches the reflective layer, and the light reaching the reflective layer is reflected by the reflective layer and returned to the micro-display unit 201, which can not only effectively prevent the propagation of photons between the micro-display units 201, but also reflect the light back to the micro-display unit 201, thereby increasing the light output of the micro-display unit 201. The insulating bottom layer has good insulation and can effectively prevent electrical interference between the micro-display units 201. The intermediate transmission layer has good optical transparency, can enhance the transmission efficiency of light and reduce the loss of light; the intermediate transmission layer can also have insulation, which is equivalent to increasing the thickness of the insulating layer in the nano-composite film 30, which can further improve the electrical isolation of the nano-composite film 30 and prevent the electric field interference between the electrodes from affecting the normal operation of the micro-display device. The protective layer is used to improve the anti-pollution and anti-physical damage performance of the nano-composite film 30, and facilitates the subsequent preparation process. Furthermore, the protective layer and the reflective layer can also be insulating materials, thereby further improving the electrical isolation of the nano-composite film 30.

[0067] An embodiment of the present invention provides a micro display device including: a driving substrate 10; a pixel array layer 20, including a plurality of micro display units 201; a surface nano-composite film 30 arranged on the driving substrate 10, including a multi-layer nano-scale film layer, located in the light emitting direction of the side wall of the micro display unit 201; wherein the multi-layer nano-scale film layer includes an insulating bottom layer, an intermediate transmission layer, a reflective layer and a protective layer which are sequentially away from the side wall. The technical solution provided by the embodiment of the present invention applies nanoscale film layers to the optical isolation and electrical isolation of the micro display unit 201; by introducing a nano-composite film 30 including an insulating bottom layer, an intermediate transmission layer, a reflective layer and a protective layer between the micro display units 201, it can not only effectively prevent the propagation of photons between pixels, improve the reflection efficiency of the side walls of the micro display unit 201, and increase the light output of the micro display unit 201, but also has excellent electrical isolation. The thickness of the nano-scale film layer can be accurately controlled through the atomic layer deposition process to achieve the electrical isolation function, which meets the needs of preparing smaller-sized micro display units 201. At the same time, each film layer in the nano-composite film 30 uses a material compatible with the manufacturing material of the micro display unit 201, which is easy to integrate and process.

[0068] The above is the core inventive concept of the present invention. The structure and position of the nanocomposite film are described in detail below.

[0069] Based on the above embodiments, optionally, the material of the insulating bottom layer includes silicon oxide; the material of the intermediate transmission layer includes tantalum pentoxide; the material of the reflective layer includes aluminum oxide; and the material of the protective layer includes polymethyl methacrylate.

[0070] Specifically, silicon oxide (SiO2) is a good insulating material, and its insulating properties are mainly attributed to its atomic structure. In a silicon dioxide crystal, the four valence electrons of a silicon atom form four covalent bonds with four oxygen atoms, the silicon atom is located at the center of a regular tetrahedron, and the four oxygen atoms are located at the four vertices of the regular tetrahedron. This structure makes it difficult for electrons to move freely, thus exhibiting excellent insulating properties. Tantalum pentoxide (Ta2O5), as a transparent ceramic material with a high refractive index, has good transparency and insulating properties. Aluminum oxide (Al2O3) has a high reflectivity, and is insulating and corrosion-resistant; at the same time, aluminum oxide also has high hardness and wear resistance. These mechanical properties help maintain its surface smoothness and reflective properties, and its reflective properties will not be significantly reduced even when worn. Polymethyl methacrylate (PMMA), also known as acrylic or organic glass, is a high molecular polymer with high strength, rigidity and resistance to atmospheric aging. In addition, the density of PMMA is about 1.15-1.19g / cm³, which is half of that of glass, making it a lightweight material with good electrical insulation properties.

[0071] Among them, the insulating bottom layer, the intermediate transmission layer and the reflective layer can be formed by atomic layer deposition (ALD) process. ALD is a precise thin film deposition process that can control the thickness and uniformity of the film layer at the atomic level, so it is particularly suitable for forming uniform nano-thin films on small sizes and complex three-dimensional structures. The advantage of this process is its highly isotropic deposition characteristics, which ensures the complete coverage of the film layer even on complex structures (such as micro-grooves, columnar protrusions and other structural surfaces), as well as the compactness and optical properties of the film layer. The thickness of the film layer can be precisely controlled within the range of 5nm-100nm to optimize the light output effect and prevent light loss. During the preparation of the nano-composite film 30, the number of layers and the thickness and surface morphology of each layer of material can be precisely adjusted to solve the problem of deposition on complex shapes (such as sidewalls) by traditional methods. In addition, the ALD process can be carried out under low temperature conditions, thereby avoiding thermal damage to the micro-display unit and ensuring the stability of the optoelectronic performance of the device. At the same time, the nano-scale film layer deposited by ALD has good adhesion and environmental stability, and can maintain high reflection and enhance light output effects during long-term use, effectively improving the brightness and contrast of the micro-display device. The protective layer made of PMMA can be formed by spin coating. Since the protective layer is formed on the side wall of the micro-display unit 201, PMMA can be dissolved in a suitable solvent (such as acetone, ethyl acetate, etc.) during spin coating, and then the solution is applied to the side wall surface and evenly distributed by rotation.

[0072] The technical solution provided by the embodiment of the present invention sets the material of the insulating bottom layer to silicon oxide, the material of the intermediate transmission layer to tantalum pentoxide, the material of the reflective layer to aluminum oxide, and the material of the protective layer to polymethyl methacrylate; silicon oxide, tantalum pentoxide, aluminum oxide and polymethyl methacrylate are all electrically insulating, which can effectively improve the electrical isolation effect of the nano-composite film 30. The refractive index of silicon oxide is lower than that of tantalum pentoxide. The combination of silicon oxide and tantalum pentoxide can form a group of DBR (Distributed Bragg Reflector), thereby improving the reflectivity of the nano-composite film 30 and reducing optical crosstalk; the combination of tantalum pentoxide and aluminum oxide can improve the light transmittance and reduce the optical crosstalk, thereby ensuring the optical isolation effect of the nano-composite film 30. The combination of aluminum oxide and polymethyl methacrylate can provide excellent mechanical strength, enhance the durability of the structure, and ensure the mechanical stability of the nano-composite film 30.

[0073] Based on the above embodiments, Figure 2 is a schematic structural diagram of another micro display device provided by an embodiment of the present invention, Figure 3 yes Figure 2 Schematic diagram of the structure of the nanocomposite membrane in the structure shown; reference Figure 3 and Figure 2 Optionally, the pixel array layer 20 further includes:

[0074] The light emitting structure layer is located on the surface of the driving substrate 10; the light emitting structure layer includes a plurality of light emitting structures 21 arranged at intervals;

[0075] The first dielectric layer 25 is located on a side of the light emitting structure 21 away from the driving substrate 10 and between two adjacent light emitting structures 21; wherein the surface of the first dielectric layer 25 away from the driving substrate 10 includes a plurality of first grooves corresponding to the light emitting structures 21;

[0076] The color conversion layer includes a plurality of color conversion units 26, each color conversion unit 26 is correspondingly located in a first groove;

[0077] The micro display unit 201 includes a light emitting structure 21 and a color conversion unit corresponding to the light emitting structure 21 ; the nano-composite film 30 is located on the side wall of the color conversion unit 26 in the light emitting direction.

[0078] Specifically, the surface of the driving substrate 10 on the side close to the pixel array layer 20 includes a plurality of first driving electrodes 11, and each micro display unit 201 is correspondingly arranged on a first driving electrode 11 and electrically connected to the first driving electrode 11. The pixel array layer 20 includes a light emitting structure layer, a first dielectric layer 25 and a color conversion layer which are sequentially away from the driving substrate 10. Among them, the light emitting structure layer includes a plurality of light emitting structures 21 arranged at intervals, and the light emitting structure 21 can be Microled. The light emitting structure 21 includes a first semiconductor layer, a light emitting layer and a second semiconductor layer which are sequentially stacked in a direction perpendicular to the driving substrate 10. The first semiconductor layer, the light emitting layer and the second semiconductor layer are respectively an N-type semiconductor layer, a quantum well layer and a P-type semiconductor layer, or a P-type semiconductor layer, a quantum well layer and an N-type semiconductor layer. The material of the first dielectric layer 25 can be silicon oxide, and the first dielectric layer 25 is located on the side of the light emitting structure 21 away from the driving substrate 10 and between two adjacent light emitting structures 21. The first dielectric layer 25 is used to achieve electrical isolation between adjacent light emitting structures 21 and prevent current leakage. In addition, the first dielectric layer 25 is also used to form a storage space for placing the color conversion unit 26. The surface of the first dielectric layer 25 away from the driving substrate 10 includes a plurality of first grooves corresponding to the light-emitting structure 21, and the color conversion unit 26 is formed in the first groove. By placing the color conversion unit 26 in the first groove, the color conversion unit 26 can be precisely aligned with the light-emitting structure 21 through the first groove, and the thickness and shape of the color conversion unit 26 can be precisely controlled by controlling the depth and shape of the first groove. The method for forming the first groove includes but is not limited to dry etching, ion beam etching, laser etching, nanoimprinting and the like.

[0079] The micro display unit 201 may include a red micro display unit, a green micro display unit and a blue micro display unit; the red micro display unit is used to emit red light, the green micro display unit is used to emit green light, and the blue micro display unit is used to emit blue light. The color conversion unit 26 in the micro display units of different colors is used to convert the light emitted by the light emitting structure 21 into light of the corresponding colors. The color conversion unit 26 in the red micro display unit 201 is used to convert the light emitted by the light emitting structure 21 below into red light, the color conversion unit 26 in the green micro display unit 201 is used to convert the light emitted by the light emitting structure 21 below into green light, and the color conversion unit 26 in the blue micro display unit 201 is used to convert the light emitted by the light emitting structure 21 below into blue light. In other embodiments, the color conversion unit 26 may not be used in the blue micro display unit 201, and the light emitting structure 21 emitting blue light may be directly used. The material of the color conversion unit 26 includes at least one of phosphor and quantum dots. The quantum dot material is a key component in the color conversion layer, which can absorb light of a specific wavelength and re-emit light of a different wavelength, thereby achieving color conversion. In Micro-LED display technology, quantum dot materials are usually used to convert blue light into red and green light to achieve full-color display. Quantum dot materials include II-VI quantum dots, III-V quantum dots and perovskite quantum dots. Phosphor is a material that can convert absorbed energy into light radiation. Phosphor has the characteristics of stable chemical properties and good luminescence performance. It can be excited by the light emitted by the light-emitting structure 21 to emit relatively pure red, green and blue light.

[0080] The technical solution provided by the embodiment of the present invention is that the first dielectric layer 25 is arranged between the light-emitting structure layer and the color conversion layer, and the first dielectric layer 25 can realize the electrical isolation between the adjacent light-emitting structures 21 to prevent the current leakage phenomenon. In addition, the first dielectric layer 25 is also used to form a storage space for placing the color conversion unit 26. By placing the color conversion unit 26 in the first groove of the first dielectric layer 25, the color conversion unit 26 can be precisely aligned with the light-emitting structure 21 through the first groove, and the thickness and shape of the color conversion unit 26 can be precisely controlled by controlling the depth and shape of the first groove. In addition, the nano-composite film 30 is arranged in the light-emitting direction of the side wall of the color conversion unit, so as to prevent the color light emitted from the side wall of the color conversion unit from interfering with the color of the light emitted by the adjacent micro-display unit 201.

[0081] Optional, reference Figure 2 and Figure 3 , the nano-composite film 30 is located on the side wall of the color conversion unit; the multi-layer nano-scale film layer includes an insulating bottom layer 31, an intermediate transmission layer 32, a reflective layer 33 and a protective layer 34 which are sequentially away from the side wall of the color conversion unit 26.

[0082] Specifically, the nanocomposite film 30 is located on the side wall of the color conversion unit 26, that is, the nanocomposite film 30 is located between the color conversion unit and the side wall of the first groove. In the process of preparing the micro display device, after a plurality of first grooves are formed on the side of the first dielectric layer 25 away from the driving substrate 10, the nanocomposite film 30 can be first formed on the side wall of the first groove, and then the color conversion unit 26 is formed in the first groove. Since the insulating bottom layer 31, the intermediate transmission layer 32, the reflective layer 33 and the protective layer 34 are sequentially arranged along the side wall away from the color conversion unit 26, in the process of preparing the nanocomposite film 30, the protective layer 34 is first coated on the groove wall of the first groove, and then the reflective layer 33, the intermediate transmission layer 32 and the insulating bottom layer 31 are sequentially formed on the surface of the protective layer 34 by an atomic deposition process. It should be noted that after the nanocomposite film 30 is formed, the nanocomposite film 30 located on the bottom surface of the first groove is removed to prevent the light emitted by the light-emitting structure 21 from being affected from entering the color conversion unit 26. The technical solution provided by the embodiment of the present invention sets the nano-composite film 30 on the side wall of the color conversion unit 26, which can hinder the propagation of light at the side wall of the color conversion unit 26 and reflect the light converted by the color conversion unit 26 at the side wall of the color conversion unit 26, thereby further reducing light crosstalk and increasing the light output of the micro display unit 201.

[0083] Based on the above embodiments, Figure 4 is a schematic structural diagram of another micro display device provided by an embodiment of the present invention, Figure 5 yes Figure 4 Schematic diagram of the structure of the nanocomposite membrane in the structure shown, refer to Figure 4 and Figure 5 In another embodiment of the present invention, the surface of the first dielectric layer 25 away from the driving substrate 10 also includes a plurality of second grooves 252, and the second groove 252 is located between two adjacent first grooves; the nano-composite film 30 is located on the sidewalls and bottom surfaces of the second grooves 252, and in other embodiments, the nano-composite film 30 is located on the sidewalls of the second grooves 252; the multi-layer nano-scale film layer includes an insulating bottom layer 31, an intermediate transmission layer 32, a reflective layer 33 and a protective layer 34 which are sequentially away from the second grooves 252.

[0084] Specifically, the second groove 252 is prepared between the first grooves by etching (including but not limited to dry etching, ion beam etching, laser etching, nanoimprinting, etc.), and then the insulating bottom layer 31, the intermediate transmission layer 32 and the reflective layer 33 are sequentially formed on the sidewall and bottom surface of the second groove 252 by an atomic deposition process; then the protective layer 34 is spin-coated on the surface of the reflective layer 33 to form the nano-composite film 30. In the embodiment of the present invention, the nano-composite film 30 is disposed in the second groove 252, and the nano-composite film 30 located on the bottom surface of the second groove 252 does not need to be removed, thereby reducing the difficulty of preparing the nano-composite film 30, and also avoiding the situation that when the nano-composite film 30 is disposed in the first groove and the nano-composite film 30 on the bottom surface of the groove is etched, the light-emitting structure 21 located at the bottom of the first groove is easily damaged due to over-etching.

[0085] Moreover, since the second groove 252 is located between adjacent first grooves, the second groove 252 and the light emitting structure 21 are staggered in a direction perpendicular to the driving substrate 10, that is, the vertical projection of the second groove 252 on the driving substrate 10 does not overlap with the vertical projection of the light emitting structure 21 on the driving substrate 10. When etching the second groove 252, the light emitting structure 21 will not be damaged, so the depth of the second groove 252 can be greater than or equal to the first groove, thereby expanding the obstruction range and reflection range of the propagation of the color light emitted from the side wall of the color conversion unit 26 by the nano-composite film 30, and improving the light isolation effect of the nano-composite film 30. In addition, the second groove 252 is located between adjacent micro-display units 201, and the second groove 252 can physically prevent electrical interference between adjacent micro-display units 201.

[0086] The technical solution provided by the embodiment of the present invention, in terms of light isolation, the composite structure formed by the nano-composite film 30 and the deep groove (the second groove 252) can reflect stray light in different directions and guide it back to the light-emitting surface. Among them, the three-dimensional figure of the second groove 252 can be a prism, a cone or a prism, etc., to further optimize the reflection and guiding effect of light. In addition, it combines physical isolation (preventing the propagation of photons) and reflection functions to form a dual optical control mechanism. In traditional reflective cups, although there is a reflection function, there is no physical isolation means. The nano-composite film 30 in the second groove 252 not only realizes light isolation, but also enables the light originally lost in the side wall to be efficiently utilized, thereby achieving a dual improvement in light isolation and reflection efficiency. In terms of electrical isolation, the composite structure formed by the nano-composite film 30 and the second groove 252 can utilize the physical isolation effect of the deep groove and the insulation of the material of the nano-composite film 30, and also form a dual electrical isolation mechanism.

[0087] On the basis of the above-mentioned embodiments, optionally, the second groove 252 is arranged around the micro-display unit 201, so as to reflect and isolate the light emitted from the side wall of the color conversion unit in various directions, further improving the optical isolation and reflection effect of the composite structure formed by the nano-composite film 30 and the second groove 252; and can also further improve the electrical isolation effect of the composite structure formed by the nano-composite film 30 and the second groove 252.

[0088] On the basis of the above embodiments, optionally, the distance from the bottom surface of the second groove 252 to the driving substrate 10 is less than or equal to the distance from the surface of the light emitting structure 21 away from the driving substrate 10 to the driving substrate 10. It can be understood that the depth of the second groove 252 can meet the depth condition for the nano-composite film 30 to isolate and reflect the light emitted from the side wall of the light emitting structure 21, so as to achieve the effect of isolating and reflecting the light emitted from the side wall of the light emitting structure 21, and increase the amount of light provided by the light emitting structure 21 to the color conversion unit 26 located directly above the light emitting structure 21.

[0089] Based on the above embodiments, optionally, the surface of the nanocomposite film 30 includes a microstructure, and the microstructure is used to reduce the amount of light emitted from the side wall of the microdisplay unit 201; wherein the microstructure includes at least one of a nano pattern, a nano hole array and a nano column array.

[0090] Specifically, microstructures such as nano patterns, nano hole arrays, and nano column arrays are arranged on the surface of the nano composite film 30 near the color conversion unit 26, which can significantly improve the reflection, scattering, and diffraction characteristics of light, thereby enhancing its photoelectric performance and further improving the utilization rate of light and color expression. The preparation of surface microstructures can be achieved by chemical self-assembly. Chemical self-assembly is a spontaneous process in which molecules or nanoparticles are automatically arranged into an ordered structure under specific conditions through intermolecular interactions (such as van der Waals forces, hydrogen bonds, electrostatic interactions, etc.). Self-assembly can form thin films, layered structures, or other ordered structures at the molecular or nanoscale, and is mainly used to manufacture highly ordered nanostructures or films, which can be used to improve the function of materials, improve surface properties, or achieve specific optical and electrical properties.

[0091] On the basis of the above embodiments, optionally, the light emitting structure 21 includes: a first current spreading layer 241, located on one side of the driving substrate 10; a first semiconductor layer, located on the side of the first current spreading layer 241 away from the driving substrate 10; a light emitting layer, located on the side of the first semiconductor layer away from the driving substrate 10; a second semiconductor layer, located on the side of the light emitting layer away from the driving substrate 10; a second current spreading layer 242, located on the side of the second semiconductor layer away from the driving substrate 10; wherein the surface of the driving substrate 10 close to the pixel array layer 20 includes a plurality of first driving electrodes 11, and the first current spreading layer 241 contacts the first driving electrodes 11. The technical solution provided by the embodiment of the present invention is conducive to the expansion of current on the surface of the first semiconductor layer and the expansion on the surface of the second semiconductor layer by arranging the first current spreading layer 241 (such as an ITO layer) on the side of the first semiconductor layer close to the driving substrate 10 and arranging the second current spreading layer 242 (such as an ITO layer) on the side of the second semiconductor layer away from the driving substrate 10. In other embodiments, the first current spreading layer 241 (such as an ITO layer) may be disposed only on a side of the first semiconductor layer close to the driving substrate 10 , or the second current spreading layer 242 (such as an ITO layer) may be disposed only on a side of the second semiconductor layer away from the driving substrate 10 .

[0092] Based on the above embodiments, optionally, the micro display device further includes:

[0093] The second dielectric layer 22 is located on the sidewall of the light emitting structure 21, the surface of the light emitting structure 21 away from the driving substrate 10, and the surface of the driving substrate 10 not covered by the light emitting structure 21; wherein the second dielectric layer 22 located on the side of the light emitting structure 21 away from the driving substrate 10 includes an electrode opening 221, and the electrode opening 221 exposes the second current spreading layer 242 of the light emitting structure 21 or the second semiconductor layer of the light emitting structure 21;

[0094] The electrode lead 23 is located between the first dielectric layer 25 and the second dielectric layer 22 . The electrode lead 23 is electrically connected to the second current spreading layer 242 or the second semiconductor layer of the light emitting structure 21 through the electrode opening 221 .

[0095] Specifically, the second dielectric layer 22 may be a dielectric material such as silicon oxide or silicon nitride. The electrode lead 23 may include a stacked ITO layer 231 and a metal layer 232. The electrode lead 23 is located between the first dielectric layer 25 and the second dielectric layer 22, thereby achieving electrical isolation of the upper and lower sides of the electrode lead 23 to prevent short circuits. Among them, the first current spreading layer 241 is in contact with the first driving electrode 11 located on the surface of the driving substrate 10; the second current spreading layer 242 or the second semiconductor layer of the light-emitting structure 21 may be electrically connected to the second driving electrode of the driving substrate 10 through the electrode lead 23. The high-voltage chip may be electrically connected to form a series structure by connecting the second semiconductor layer (such as an N-type semiconductor layer) of one chip to the first semiconductor layer (such as a P-type semiconductor layer) of another chip, and may be connected in series in a vertical direction or a horizontal direction. In the present invention, the light-emitting structure 21 may improve the light-emitting efficiency of the light-emitting structure 21 by using two chips connected in series in a vertical direction, and may also increase the area of ​​the light-emitting region of the micro-display device.

[0096] The embodiment of the present invention further provides a method for preparing a micro display device, which is used to form the micro display device described in any of the above embodiments. Figure 6 is a flow chart of a method for preparing a micro display device provided by an embodiment of the present invention, with reference to Figure 6 , the preparation method of the micro display device comprises:

[0097] S10, providing a driving substrate.

[0098] S20, forming a pixel array layer on one side of the driving substrate; the pixel array includes a plurality of micro display units arranged on the surface of the driving substrate.

[0099] S30, forming a nano-composite film, the nano-composite film includes a plurality of nano-scale film layers, and is located in the light emitting direction of the side wall of the micro display unit; wherein the plurality of nano-scale film layers include an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall.

[0100] The embodiment of the present invention provides a method for preparing a micro display device. By arranging a nano-composite film 30 including an insulating bottom layer 31, an intermediate transmission layer 32, a reflective layer 33 and a protective layer 34 in the light emitting direction of the side wall of the micro display unit 201, the nano-scale film layer is applied to the optical isolation and electrical isolation of the micro display unit 201. It can not only effectively prevent the propagation of photons between pixels, improve the reflection efficiency of the side wall of the micro display unit 201, and increase the light output of the micro display unit 201, but also has excellent electrical isolation effect. The thickness of the nano-scale film layer can be accurately controlled by the atomic layer deposition process to achieve the electrical isolation function, which meets the needs of preparing a smaller size of the micro display unit 201. At the same time, each film layer in the nano-composite film 30 adopts a material compatible with the manufacturing material of the micro display unit 201, which is easy to integrate and process.

[0101] Optionally, step S20 of forming a pixel array layer on one side of the driving substrate includes:

[0102] S210 , forming a light-emitting structure layer on a surface of a driving substrate, wherein the light-emitting structure layer includes a plurality of light-emitting structures arranged at intervals.

[0103] Specifically, refer to Figure 7 , the surface of the driving substrate 10 close to the pixel array layer 20 includes a plurality of first driving electrodes 11. The light-emitting structure 21 may be a MicroLED. The light-emitting structure 21 includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked in sequence. The first semiconductor layer, the light-emitting layer, and the second semiconductor layer are respectively an N-type semiconductor layer, a quantum well layer, and a P-type semiconductor layer, or a P-type semiconductor layer, a quantum well layer, and an N-type semiconductor layer. After forming a plurality of light-emitting structures 21, the array of light-emitting structures 21 grown on the epitaxial substrate can be quickly and accurately transferred to the driving substrate 10 through mass transfer technology, and a good electrical connection and mechanical fixation are formed between the driving circuit in the driving substrate 10, thereby forming a light-emitting structure layer on the surface of the driving substrate 10. Among them, the light-emitting structure 21 is arranged on the side of the first driving electrode 11 away from the driving backplane, and is electrically connected to the first driving electrode 11.

[0104] Optional, reference Figure 8 Before forming the first dielectric layer 25 on the side of the light emitting structure 21 away from the driving substrate 10 and between two adjacent light emitting structures 21, the method further includes: forming a second dielectric layer 22 on the side wall of the light emitting structure 21, the surface of the light emitting structure 21 away from the driving substrate 10, and the surface of the driving substrate 10 not covered by the light emitting structure 21; forming an electrode opening 221 in the second dielectric layer 22 located on the side of the light emitting structure 21 away from the driving substrate 10, the electrode opening 221 exposing the light emitting structure 21; forming an electrode lead 23 on the side of the second dielectric layer 22 away from the driving substrate 10, the electrode lead 23 being electrically connected to the light emitting structure 21 through the electrode opening 221.

[0105] Specifically, the second dielectric layer 22 can be made of dielectric materials such as silicon oxide and silicon nitride. The electrode lead 23 can include a stacked ITO layer 231 and a metal layer 232. The electrode lead 23 is located between the first dielectric layer 25 and the second dielectric layer 22, thereby achieving electrical isolation of the upper and lower sides of the electrode lead 23 to prevent short circuits. Furthermore, the light-emitting structure 21 also includes a first current spreading layer 241 disposed on a side close to the drive substrate 10 and / or a second current spreading layer 242 located on a side of the second semiconductor layer away from the drive substrate 10, which is conducive to the expansion of current on the surface of the first semiconductor layer and / or on the surface of the second semiconductor layer. Wherein, in the case of having a first current spreading layer 241, the first current spreading layer 241 is in contact with the first drive electrode 11 located on the surface of the drive substrate 10; in the case of having a second current spreading layer 242, the second current spreading layer 242 can be electrically connected to the second drive electrode of the drive substrate 10 through the electrode lead 23.

[0106] S220, forming a first dielectric layer on a side of the light emitting structure away from the driving substrate and between two adjacent light emitting structures, and forming a plurality of first grooves corresponding to the light emitting structures on a surface of the first dielectric layer away from the driving substrate.

[0107] For details, refer to Fig. 9 and Fig.10 , a first dielectric layer 25 can be formed on the side of the light emitting structure 21 away from the driving substrate 10 and between two adjacent light emitting structures 21 by chemical vapor deposition. The material of the first dielectric layer 25 can be silicon oxide. The first dielectric layer 25 is used to achieve electrical isolation between adjacent light emitting structures 21 to prevent current leakage. In addition, the first dielectric layer 25 is also used to form a accommodating space for placing the color conversion unit 26. A plurality of first grooves 251 corresponding to the light emitting structures 21 are formed on the surface of the first dielectric layer 25 on the side away from the driving substrate 10. Methods for forming the first grooves 251 include but are not limited to dry etching, ion beam etching, laser etching, nanoimprinting and the like.

[0108] S230 , forming a color conversion layer on a side of the first dielectric layer away from the driving substrate, wherein the color conversion layer comprises a plurality of color conversion units, and each color conversion unit is correspondingly located in a first groove.

[0109] Specifically, refer to Figure 2 and Figure 4 The color conversion unit 26 corresponding to the light emitting structure 21 is formed in the first groove, and the color conversion unit 26 and the light emitting structure 21 can be precisely aligned through the first groove, and the thickness and shape of the color conversion unit 26 can be precisely controlled by controlling the depth and shape of the first groove. The material of the color conversion unit 26 includes at least one of phosphor and quantum dots.

[0110] Optionally, the step of forming the nanocomposite film 30 may be performed before or after forming the color conversion layer.

[0111] In the case where the step of forming the nanocomposite film 30 is performed before the step of forming the color conversion layer, refer to Fig.11 Step S30 of forming the nanocomposite film 30 includes: spin coating a protective layer 34 on the sidewall of the first groove 251; and sequentially forming a reflective layer 33, an intermediate transmission layer 32 and an insulating bottom layer 31 on the surface of the protective layer 34 by an atomic deposition process.

[0112] In the case where the step of forming the nanocomposite film 30 is after the step of forming the color conversion layer, refer to Fig.12 and Figure 4 Step S30 includes: forming a plurality of second grooves 252 on the surface of the first dielectric layer 25 away from the driving substrate 10, wherein the second groove 252 is located between two adjacent first grooves 251; sequentially forming an insulating bottom layer 31, an intermediate transmission layer 32 and a reflective layer 33 on the sidewalls and bottom of the second grooves 252 by an atomic deposition process; and spin coating a protective layer 34 on the surface of the reflective layer 33.

[0113] Based on the above embodiments, optionally, the material of the insulating bottom layer 31 includes silicon oxide; the material of the intermediate transmission layer 32 includes tantalum pentoxide; the material of the reflective layer 33 includes aluminum oxide; and the material of the protective layer 34 includes polymethyl methacrylate.

[0114] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A micro display device, characterized in that: include: Driver substrate; A pixel array layer, comprising a plurality of micro display units, arranged on the surface of the driving substrate; A nanocomposite film, comprising a multi-layer nanoscale film layer, located in the light-emitting direction of the side wall of the microdisplay unit; wherein the multi-layer nanoscale film layer comprises an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall; The pixel array layer further includes: A light emitting structure layer is located on the surface of the driving substrate; the light emitting structure layer includes a plurality of light emitting structures arranged at intervals; A first dielectric layer is located on a side of the light emitting structure away from the driving substrate and between two adjacent light emitting structures; wherein a surface of the first dielectric layer away from the driving substrate comprises a plurality of first grooves corresponding to the light emitting structures; A color conversion layer, comprising a plurality of color conversion units, each of the color conversion units being located in a corresponding first groove; Wherein, the micro display unit includes a light-emitting structure and a color conversion unit corresponding to the light-emitting structure; the nanocomposite film is located in the light-emitting direction of the side wall of the color conversion unit; The surface of the first dielectric layer at a side away from the driving substrate further comprises a plurality of second grooves, wherein the second grooves are located between two adjacent first grooves; and the nanocomposite film is located on the sidewalls of the second grooves.

2. The micro display device according to claim 1, characterized in that: The material of the insulating bottom layer includes silicon oxide; the material of the intermediate transmission layer includes tantalum pentoxide; the material of the reflective layer includes aluminum oxide; and the material of the protective layer includes polymethyl methacrylate.

3. The micro display device according to claim 1, characterized in that: The nanocomposite film is also located on the side wall of the color conversion unit; the multi-layer nanoscale film layer includes an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall of the color conversion unit; And / or, the nanocomposite film is located on the sidewalls and bottom surface of the second groove; the multi-layer nanoscale film layer includes an insulating bottom layer, an intermediate transmission layer, a reflective layer and a protective layer which are sequentially away from the second groove.

4. The micro display device according to claim 3, characterized in that: The second groove is arranged around the micro display unit; And / or, the distance from the bottom surface of the second groove to the driving substrate is less than or equal to the distance from the surface of the light emitting structure away from the driving substrate to the driving substrate.

5. The micro display device according to claim 1, characterized in that: The surface of the nanocomposite film includes a microstructure, and the microstructure is used to reduce the amount of light emitted from the side wall of the microdisplay unit; Wherein, the microstructure includes at least one of a nano pattern, a nano hole array and a nano column array.

6. The micro display device according to claim 1, characterized in that: The light emitting structure comprises: A first semiconductor layer, located on one side of the driving substrate; a light emitting layer, located on a side of the first semiconductor layer away from the driving substrate; A second semiconductor layer is located on a side of the light emitting layer away from the driving substrate; A current spreading layer is provided on at least one of a side of the first semiconductor layer facing the driving substrate and a side of the second semiconductor layer away from the driving substrate; The surface of the driving substrate close to the pixel array layer includes a first driving electrode and a second driving electrode, the first semiconductor layer is electrically connected to the first driving electrode, and the second semiconductor layer is electrically connected to the second driving electrode.

7. The micro display device according to claim 6, characterized in that: Also includes: a second dielectric layer located on a side wall of the light emitting structure, a surface of the light emitting structure away from the driving substrate, and a surface of the driving substrate not covered by the light emitting structure; wherein the second dielectric layer located on a side of the light emitting structure away from the driving substrate comprises an electrode opening, and the electrode opening exposes a second semiconductor layer or a current spreading layer of the light emitting structure; The electrode lead is located between the first dielectric layer and the second dielectric layer, and the electrode lead is electrically connected to the second semiconductor layer or the current spreading layer through the electrode opening.

8. A method for preparing a micro display device, characterized in that: A micro display device for forming any one of claims 1 to 7, comprising: Providing a drive substrate; A pixel array layer is formed on one side of the driving substrate; the pixel array includes a plurality of micro display units arranged on a surface of the driving substrate; A nanocomposite film is formed, which includes a plurality of nanoscale film layers and is located in the light emitting direction of the side wall of the microdisplay unit; wherein the plurality of nanoscale film layers include an insulating bottom layer, an intermediate transmission layer, a reflection layer and a protective layer which are sequentially away from the side wall.

9. The method for preparing a micro display device according to claim 8, characterized in that: The step of forming a pixel array layer on one side of the driving substrate comprises: forming a light-emitting structure layer on the surface of the driving substrate, wherein the light-emitting structure layer includes a plurality of light-emitting structures arranged at intervals; A first dielectric layer is formed on a side of the light emitting structure away from the driving substrate and between two adjacent light emitting structures, and a plurality of first grooves corresponding to the light emitting structures are formed on a surface of the first dielectric layer away from the driving substrate; A color conversion layer is formed on a side of the first dielectric layer away from the driving substrate, wherein the color conversion layer has a plurality of color conversion units, and each of the color conversion units is correspondingly located in one of the first grooves; The forming of the nanocomposite film comprises: Spin coating a protective layer on the sidewall of the first trench; Forming a reflective layer, an intermediate transmission layer and an insulating bottom layer in sequence on the surface of the protective layer by an atomic deposition process; Alternatively, the forming of the nanocomposite film comprises: A plurality of second grooves are formed on a surface of the first dielectric layer away from the driving substrate, wherein the second grooves are located between two adjacent first grooves; forming an insulating bottom layer, an intermediate transmission layer and a reflective layer in sequence on the sidewall and bottom of the second trench by an atomic deposition process; A protective layer is spin-coated on the surface of the reflective layer.

Images