Micro-display light-emitting pixel and micro-display screen

Abstract

The utility model discloses a micro-display light-emitting pixel and a micro-display screen, and relates to the technical field of semiconductors. The micro-display light-emitting pixel comprises a driving backboard, a light-emitting layer and a light-emitting layer, wherein an anode contact is arranged in the driving backboard; the display module is arranged on the driving back plate, the display module comprises a light-emitting unit connected with the anode contact, and the periphery of the light-emitting unit is covered with a transparent conducting layer protruding in the direction away from the driving back plate; a part of the surface of the transparent conductive layer is electroplated with a reflective metal structure, so that the reflective metal structure surrounds the side wall of the light-emitting unit. Based on the technical scheme provided by the invention, the technical process of the reflective metal structure can be optimized by directly electroplating the reflective metal structure on the transparent conductive layer.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and in particular to a micro-display luminous pixel and a micro-display screen. Background Art

[0002] Micro LED is regarded as the best solution in the display field due to its advantages such as high resolution, low power consumption, high brightness and long life.

[0003] In order to improve the brightness of micro-display light-emitting pixels and reduce light crosstalk, a process of negative photoresist lithography, metal plating, lift-off, and stripping is usually used to prepare a reflective metal structure near the light-emitting unit. Specifically: negative photoresist is used for photolithography on part of the top of the light-emitting unit; then metal plating is performed so that the metal covers the negative photoresist area and the non-resist area; then the metal film layer on the negative photoresist area is separated by the lift-off process; finally, the negative photoresist is removed to complete the patterning of the reflective metal structure, and a reflective metal structure corresponding to the non-resist area is obtained.

[0004] However, due to the small size of the micro-display luminous pixels, when using the above-mentioned preparation method, since the gold tearing process requires the use of negative photoresist, and the thickness of the negative photoresist must be greater than the thickness of the required metal film layer, small-size patterning is more difficult while ensuring the thickness of the negative photoresist. It is easy to have problems such as abnormal photoresist peeling pattern and sidewall metal breakage, which directly affects the preparation effect of the reflective metal structure, and then affects the brightness and yield of the micro-display luminous pixels. Utility Model Content

[0005] The utility model aims to provide a micro-display luminous pixel and a micro-display screen, which optimize the process flow of the reflective metal structure by directly electroplating the reflective metal structure on a transparent conductive layer.

[0006] In order to achieve the above-mentioned utility model purpose, the utility model proposes the following technical solutions:

[0007] In one aspect, a micro display luminous pixel is provided, the micro display luminous pixel comprising:

[0008] A driving back plate having an anode contact therein;

[0009] A display module is arranged on the driving backplane, and the display module includes a light-emitting unit that is electrically connected to the anode contact, and the outer periphery of the light-emitting unit is covered with a transparent conductive layer that protrudes in a direction away from the driving backplane, and a reflective metal structure is electroplated on a part of the surface of the transparent conductive layer so that the reflective metal structure surrounds the side wall of the light-emitting unit.

[0010] In a possible implementation, the transparent conductive layer includes:

[0011] A first conductive layer, the first conductive layer is coated on the outer periphery of a surface of the light emitting unit away from the driving backplane;

[0012] A second conductive layer, the second conductive layer is coated on the outer periphery of the side wall of the light emitting unit;

[0013] A third conductive layer, the third conductive layer is coated on the outer periphery of a surface of the driving back plate facing the light-emitting unit;

[0014] The reflective metal structure is electroplated on the second conductive layer and / or the third conductive layer.

[0015] In a possible implementation, the reflective metal structure includes:

[0016] The first reflective metal structure is closely disposed on a side surface of the second conductive layer away from the light emitting unit and a side surface of the third conductive layer away from the driving backplane.

[0017] In a possible implementation manner, the thickness of the first reflective metal structure is within a range of 10 to 1000 nm.

[0018] In a possible implementation, the reflective metal structure includes:

[0019] A second reflective metal structure is stacked and arranged on a surface of a side of the third conductive layer away from the driving back plate.

[0020] In a possible implementation, the top height of the second reflective metal structure is not lower than the top height of the light emitting unit, and the height of the second reflective metal structure exceeding the top of the light emitting unit does not exceed 1 / 3 of the overall height of the light emitting unit.

[0021] In a possible implementation manner, a distance between the second reflective metal structure and the light emitting unit is between 1 / 4 and 1 / 2 of a diameter of the light emitting unit.

[0022] In a possible implementation, the light-emitting unit includes a bonding metal layer and a compound pixel layer stacked from bottom to top, and the surface size of the bonding metal layer is larger than the surface size of the compound pixel layer;

[0023] The second reflective metal structure is also stacked on a portion of a side surface of the second conductive layer corresponding to the bonding metal layer.

[0024] In a possible implementation, a passivation layer is provided between the light-emitting unit and the transparent conductive layer, and the passivation layer is covered on a surface of a portion of the light-emitting unit away from the driving backplane, on a side wall of the light-emitting unit, and on a surface of the driving backplane facing the light-emitting unit.

[0025] In a possible implementation manner, the reflective metal structure includes at least one of the following layers:

[0026] An adhesive layer for achieving the adhesion capability of the reflective metal structure;

[0027] A reflective layer, used to realize the light reflection capability of the reflective metal structure;

[0028] Protective layer used to protect the metal in reflective metal structures.

[0029] In another aspect, a micro display screen is provided, the micro display screen comprising:

[0030] A micro display screen backplane, the micro display screen backplane comprising a driving circuit, an input interface and an output interface;

[0031] A display area, the display area is arranged on the back panel of the micro display screen, and the display area includes at least two display modules included in the micro display light-emitting pixels as described in the above aspects, and at least two of the display modules are arranged in an array;

[0032] A peripheral common cathode is electrically connected to each of the display modules.

[0033] Compared with the prior art, the utility model has the following beneficial effects:

[0034] A transparent conductive layer that protrudes in a direction away from the driving backplane is covered on the outer periphery of the light-emitting unit, and a reflective metal structure is further electroplated on part of the surface of the transparent conductive layer so that the reflective metal structure surrounds the side wall of the light-emitting unit, thereby achieving the effect of reducing optical crosstalk. On the one hand, the reflective metal structure is prepared by electroplating, and there is no need for a gold tearing process, and the photolithography requirements are low, thereby avoiding problems such as photolithography difficulties, patterning anomalies and metal fractures that occur under small sizes. On the other hand, compared with traditional electroplating processes, the reflective metal structure is formed by direct electroplating on the transparent conductive layer, and there is no need for additional growth of the reflective metal structure and removal of the electroplating seed layer, thereby optimizing the process flow of the reflective metal structure.

[0035] Furthermore, the reflective metal structure can be designed as a first reflective metal structure that is closely attached to the side wall of the light-emitting unit, which can effectively limit the light emitted from the side wall and prevent light crosstalk between pixels.

[0036] Furthermore, the reflective metal structure can be designed as a second reflective metal structure that is spaced a certain distance from the side wall of the light-emitting unit. While preventing light crosstalk, it can also reflect the side wall light to the front light-emitting surface of the light-emitting unit above, thereby increasing the front light intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the structure of a micro-display luminous pixel provided in an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of the structure of a micro-display luminous pixel provided in an embodiment of the present application;

[0039] Figure 3 is a method flow chart of a method for preparing a micro-display luminous pixel provided in an embodiment of the present application;

[0040] Figure 4 It is a schematic diagram of the structure of a micro display light-emitting pixel prepared with a transparent conductive layer provided in an embodiment of the present application;

[0041] Figure 5 It is a schematic diagram of the structure of a micro display light-emitting pixel prepared with a photoresist layer provided in an embodiment of the present application;

[0042] Figure 6 It is a schematic structural diagram of a micro-display luminous pixel prepared with a reflective metal structure provided in an embodiment of the present application;

[0043] Figure 7 It is a schematic diagram of the structure of a micro display light-emitting pixel prepared with a photoresist layer provided in an embodiment of the present application;

[0044] Figure 8 It is a schematic structural diagram of a micro-display luminous pixel prepared with a reflective metal structure provided in an embodiment of the present application;

[0045] Fig. 9 It is a structural schematic diagram of a micro display screen provided in an embodiment of the present application.

[0046] Reference numerals:

[0047] 10-driving backplane, 20-display module, 30-light-emitting unit, 31-bonding metal layer, 32-compound pixel layer, 40-transparent conductive layer, 41-first conductive layer, 42-second conductive layer, 43-third conductive layer, 50-reflective metal structure, 60-passivation layer, 70-anode contact, 80-photoresist layer, 200-micro display screen, 300-micro display screen backplane, 400-display area, 500-peripheral common cathode, 600-external IO interface. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0049] In the description of the present utility model, it should be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The reflective metal structure is manufactured based on the traditional negative photolithography, metal coating, lift off and photoresist stripping process. The method of using negative photoresist for photolithography and then sputtering the coated metal is prone to problems such as photoresist peeling pattern abnormalities and sidewall metal fractures, which directly affect the brightness and yield of the micro-display luminous pixels.

[0052] In order to avoid the above problems, in an embodiment of the present application, a reflective metal structure is directly electroplated on the transparent conductive layer. The photolithography requirements are low, both positive and negative photoresists can be used, and the thickness of the photoresist layer does not need to be greater than the metal. The patterning process is stable. If the resulting reflective metal structure has corresponding steps, the coverage is good. Compared with the traditional electroplating process, there is no need to grow an additional electroplating seed layer, thereby further optimizing the process flow.

[0053] First, the specific structure of the micro-display luminous pixel proposed in this application is described.

[0054] The present application embodiment provides a micro-display luminous pixel (hereinafter referred to as micro-display luminous pixel) with a reflective metal structure. The micro-display luminous pixel corresponds to the nanometer level and the micrometer level, such as Figure 1 , Figure 2 As shown, the micro display luminous pixel includes:

[0055] A driving backplane 10, wherein the driving backplane 10 has an anode contact 70; a display module 20, wherein the display module 20 is disposed on the driving backplane 10, and wherein the display module includes a light-emitting unit 30 that is electrically connected to the anode contact 70, wherein the outer periphery of the light-emitting unit 30 is covered with a transparent conductive layer 40 that protrudes in a direction away from the driving backplane 10, and a reflective metal structure 50 is electroplated on a portion of the surface of the transparent conductive layer 40 so that the reflective metal structure 50 surrounds the side wall of the light-emitting unit 30.

[0056] The driving backplane 10 is an active driving backplane that is a combination of one or more thin film transistors (TFT), low temperature polycrystalline silicon (LTPS), CMOS integrated circuits, high mobility transistors (HEMT), etc. Specifically, the driving backplane 10 is provided with a driving circuit, and the driving circuit is provided with at least one anode contact 70, and the driving circuit may include an active, passive or semi-passive control circuit. All anode contacts included in the driving circuit may be arranged linearly or in an array, and any anode contact 70 is located in the middle or at the edge of the driving backplane 10, which is not limited in this embodiment.

[0057] Among them, the display module 20 is designed with a light-emitting unit 30, and the light-emitting unit 30 in the display module 20 is mainly made of compound semiconductors, which are usually wafers or suitable size areas cut from wafers. Taking a wafer as an example, the wafer refers to a compound formed by two or more elements with a certain atomic ratio, and has semiconductor properties such as a certain bandgap width and band structure. It can be a crystalline inorganic compound (such as III-V group, II-VI group compound semiconductor), and then a layer for forming electrical contact is prepared on the surface of the compound, and when the compound is stacked later, it can be arbitrarily combined to finally form a compound pixel layer in the light-emitting unit 30. In this embodiment, the light-emitting unit 30 involves ultraviolet light, green light, blue light AlGaN, InGaN ternary material system, and its substrate material can be GaN, Si, SiC, Sapphire, etc., as well as red light, infrared and other long waves, where the red light can be the InGaN ternary material system or the quaternary AlGaInP red light compound LED epitaxy of the GaAs substrate, and the infrared mainly includes the compound epitaxy of the InP, GaAs, AlGaAs and other material systems. In addition, this embodiment does not limit the shape corresponding to the top view of the light-emitting unit 30, which can be a circle or other polygons, such as a rectangle, a hexagon, an octagon, etc.

[0058] Among them, a transparent conductive layer 40 for ohmic contact is grown on the light-emitting unit 30, and the transparent conductive layer 40 is connected to the N-type ohmic contact surface on the top of the light-emitting unit 30. The transparent conductive layer 40 covers the outer periphery of the light-emitting unit 30. Since the light-emitting unit 30 protrudes on the surface of the driving backplane 10, the transparent conductive layer 40 as a whole protrudes in the direction away from the driving backplane 10. The material used for the transparent conductive layer 40 includes but is not limited to: a combination of one or more of ITO (Indium Tin Oxide) film, AZO (Antimony doped Zinc Oxide) film, ATO (Antimony doped Tin Oxide) film, and FTO (Fluorine doped Tin Oxide) film. The present application does not limit the specific material of the transparent conductive layer 40.

[0059] Part of the surface of the transparent conductive layer 40 is electroplated with a reflective metal structure 50. Since the transparent conductive layer 40 itself is conductive, there is no need to grow an additional electroplating seed layer before electroplating. The transparent conductive layer 40 itself serves as an electroplating seed layer to provide a good conductive layer for the subsequent electroplating process and increase the adhesion of the reflective metal structure 50 to be subsequently electroplated.

[0060] Further, the electroplated reflective metal structure 50 may specifically include at least one type of layer among an adhesion layer, a reflection layer, and a protective layer, and each type of layer may be specifically implemented as one or more segments in the reflective metal structure. The adhesion layer is used to realize the adhesion ability of the reflective metal structure 50. To match different reflective layer structures, its materials include but are not limited to Ni, Cr, Ti, etc. The reflective layer is used to reflect the light emitted by the light-emitting unit 30, realize the light reflection ability of the reflective metal structure 50, and to be applied to the reflection scenes required by different light-emitting units 30, its materials include but are not limited to Al, Ag, Au, etc. Specifically, in the visible light band (400-700nm), Al and Ag are almost completely reflective (reflectivity>85%) and thus appear silvery white, while Au has a low reflectivity for short wavelengths (<500nm, blue-purple) and appears yellow. Therefore, in the optoelectronic field, Au is often used as a reflective layer material for red light, and Ag and Al are often used as reflective layer materials for blue-green. The protective layer is used to protect the metal in the reflective metal structure 50 to prevent metal oxidation and electromigration, and its material includes but is not limited to TiN, etc. Exemplarily, the reflective metal structure 50 is specifically designed as follows: an adhesion layer Ni (10nm), a reflective layer Ag (70nm), an adhesion layer Ni (20nm); an adhesion layer Ti (20nm), a protective layer TiN (50nm), a reflective layer Al (150nm), and a protective layer TiN (80nm).

[0061] Furthermore, in order to take into account both reflection and current expansion, the thickness of the reflective layer in the vertical direction needs to be appropriately increased, and can be designed to be several dozen times the thickness of the adhesion layer and the protective layer. Exemplarily, the reflective metal structure 50 is specifically designed as follows: adhesion layer Cr (10nm), reflection layer Au (500nm), adhesion layer Ti (15nm); adhesion layer Cr (50nm), reflection layer Al (150nm), adhesion layer (Ti / Pt)*3 ((150 / 40nm)*3), reflection layer Au (1500nm), the thickness of the last layer of Au is determined according to needs, for example, it is designed to be 1.5um, 1.8um, 3.0um.

[0062] It can be understood that the above description is only an example, and the present application does not limit the material of the reflective metal structure 50 .

[0063] Further, the transparent conductive layer 40 includes: a first conductive layer 41, which is coated on the outer periphery of the surface of the side of the light-emitting unit 30 away from the driving backplane 10; a second conductive layer 42, which is coated on the outer periphery of the side wall of the light-emitting unit 30; a third conductive layer 43, which is coated on the outer periphery of the surface of the side of the driving backplane 10 facing the light-emitting unit 30; and a reflective metal structure 50 electroplated on the second conductive layer 42 and / or the third conductive layer 43. That is, the first conductive layer 41 corresponds to the front light-emitting surface of the light-emitting unit 30. Therefore, in order not to affect the light-emitting effect of the front light-emitting surface, the reflective metal structure 50 is not electroplated on the surface of the first conductive layer 41, and the reflective metal structure 50 can be electroplated on the second conductive layer 42 of the side wall of the light-emitting unit 30 and on the third conductive layer 43 on the driving backplane 10. It is understandable that the reflective metal structure 50 may be electroplated on the entire second conductive layer 42 and / or the third conductive layer 43 , or may be electroplated on a portion of the second conductive layer 42 and / or the third conductive layer 43 , and the present application does not impose any limitation on this.

[0064] In one possible implementation, Figure 1 As shown, the reflective metal structure 50 includes: a first reflective metal structure, which is arranged closely on the side surface of the second conductive layer 42 away from the light-emitting unit 30 and the side surface of the third conductive layer 43 away from the driving backplane 10. That is, the reflective metal structure 50 can be designed as a first reflective metal structure close to the side wall of the light-emitting unit 30, so as to effectively converge the light-emitting angle, limit the light from the side wall, and prevent light crosstalk between pixels. At the same time, the electroplating process can avoid the side wall metal fracture phenomenon that occurs during the metal evaporation process.

[0065] Furthermore, the thickness of the first reflective metal structure is 10 to 1000 nm, that is, the first reflective metal structure only needs a thinner metal layer to achieve the sidewall reflection effect, thereby saving process costs.

[0066] In another possible implementation, Figure 2 As shown, the reflective metal structure 50 includes: a second reflective metal structure, which is stacked on a side surface of the third conductive layer 43 away from the driving backplane 10. That is, the reflective metal structure 50 can be designed as a second reflective metal structure spaced a certain distance from the side wall of the light-emitting unit 30, which can reflect the light emitted from the side wall of the light-emitting unit 30 to prevent light crosstalk, and can also reflect the light emitted from the side wall to the front light-emitting surface of the light-emitting unit 30 above, thereby increasing the intensity of the front light and reducing the brightness loss.

[0067] Furthermore, the top height of the second reflective metal structure is not lower than the top height of the light emitting unit 30, and the height of the portion of the second reflective metal structure that exceeds the top of the light emitting unit 30 is not more than 1 / 3 of the overall height of the light emitting unit 30. By designing the top height of the electroplated second reflective metal structure to be not lower than the top height of the light emitting unit 30, the reflection effect of the second reflective metal structure on the side light emitted by the light emitting unit 30 can be effectively guaranteed.

[0068] Furthermore, the distance between the second reflective metal structure and the light emitting unit 30 is between 1 / 4 and 1 / 2 of the diameter of the light emitting unit 30. The distance between the second reflective metal structure and the light emitting unit 30 is controlled to achieve a better reflection effect.

[0069] Further, such as Figure 2 As shown, the light-emitting unit 30 includes a bonding metal layer 31 and a compound pixel layer 32 stacked from bottom to top, and the surface size of the bonding metal layer 31 is larger than the surface size of the compound pixel layer 32; the second reflective metal structure is also stacked on a portion of the side surface of the second conductive layer 42 corresponding to the bonding metal layer 31. In the case where the light-emitting unit 30 has a step-like structure through the bonding metal layer 31 and the compound pixel layer 32, the reflective metal structure 50 can be prepared on the side surface of the second conductive layer 42 corresponding to the bonding metal layer 31 in addition to being prepared on the third conductive layer 43, so as to increase the surface size of the reflective metal structure 50 in the horizontal direction and reduce the difficulty of preparing the reflective metal structure 50.

[0070] Further, such as Figure 1 , Figure 2 As shown, there is a passivation layer 60 between the light emitting unit 30 and the transparent conductive layer 40, and the passivation layer 60 is covered on a part of the surface of the light emitting unit 30 away from the driving backplane 10, on the side wall of the light emitting unit 30, and on the side surface of the driving backplane 10 facing the light emitting unit 30. That is, the passivation layer 60 is first covered on the surface of the light emitting unit 30 to insulate the cathode and anode of the light emitting unit 30, and then the transparent conductive layer 40 is further covered on the surface of the passivation layer 60. In order to realize the connection between the transparent conductive layer 40 and the N-type ohmic contact layer on the top of the light emitting unit 30, the passivation layer 60 does not completely cover the surface of the side of the light emitting unit 30 away from the driving backplane 10, and the passivation layer 60 is formed with an opening, and the transparent conductive layer 40 is directly covered on the top of the light emitting unit 30 through the opening, and is connected to the N-type ohmic contact layer on the top of the light emitting unit 30. Among them, the passivation layer 60 can be a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. The present application does not limit the specific material medium of the passivation layer 60.

[0071] It can be understood that the above description only assumes that one light-emitting unit 30 is formed on the driving backplane 10. In the case where multiple light-emitting units 30 are formed on the driving backplane 10, a transparent conductive layer 40 that protrudes in the direction away from the driving backplane 10 can be analogously covered around the outer periphery of the multiple light-emitting units 30 to form a common cathode, and a corresponding reflective metal structure 50 can be electroplated on a partial surface of the transparent conductive layer 40 for each light-emitting unit 30 to avoid optical crosstalk.

[0072] In summary, the micro-display light-emitting pixel provided in the embodiment of the present application is covered with a transparent conductive layer protruding in the direction away from the driving backplane on the outer periphery of the light-emitting unit, and a reflective metal structure is further electroplated on a portion of the surface of the transparent conductive layer so that the reflective metal structure surrounds the side wall of the light-emitting unit, thereby achieving the effect of reducing optical crosstalk. On the one hand, the reflective metal structure is prepared by electroplating, and there is no need for a gold tearing process, and the photolithography requirements are low, thereby avoiding the problems of photolithography difficulties, patterning anomalies and metal fractures that occur under small sizes. On the other hand, compared with the traditional electroplating process, the reflective metal structure is directly formed by electroplating on the transparent conductive layer, and there is no need for additional growth of the reflective metal structure and removal of the electroplating seed layer, thereby optimizing the process flow of the reflective metal structure.

[0073] Furthermore, the reflective metal structure can be designed as a first reflective metal structure that is closely attached to the side wall of the light-emitting unit, which can effectively limit the light emitted from the side wall and prevent light crosstalk between pixels.

[0074] Furthermore, the reflective metal structure can be designed as a second reflective metal structure that is spaced a certain distance from the side wall of the light-emitting unit. While preventing light crosstalk, it can also reflect the side wall light to the front light-emitting surface of the light-emitting unit above, thereby increasing the front light intensity.

[0075] Next, the method for preparing the micro-display luminescent pixel described in the above embodiment is described. The method is used to prepare the micro-display luminescent pixel described in the above embodiment. Figure 3 As shown, the method may include the following steps:

[0076] S1: Prepare a driver backplane.

[0077] Exemplarily, the driving back plate includes a penetrating anode contact, and an insulating medium is disposed around the anode contact.

[0078] S2: Prepare a display module, which is arranged on a driving backplane. The display module includes a light-emitting unit that is conductive with an anode contact. The outer periphery of the light-emitting unit is covered with a transparent conductive layer that protrudes in a direction away from the driving backplane. A reflective metal structure is electroplated on a portion of the surface of the transparent conductive layer so that the reflective metal structure surrounds the side wall of the light-emitting unit.

[0079] Exemplarily, the light-emitting unit at least includes a bonding metal layer and a compound pixel layer stacked in sequence from bottom to top, wherein the top of the compound pixel layer is an N-type ohmic contact layer.

[0080] Wherein, S2 may specifically include the following steps:

[0081] S21: forming a light-emitting unit on the driving backplane.

[0082] Specifically, conductive materials can be plated on the surfaces of the compound wafer and the driving backplane to form a first bonding layer and a second bonding layer respectively; the compound wafer and the driving backplane are bonded at the wafer level through the first bonding layer and the second bonding layer, and the first bonding layer and the second bonding layer form a bonding metal layer; the substrate of the bonded and integrated compound wafer is removed to obtain a compound pixel layer with an exposed N-type ohmic contact layer; the compound pixel layer and the bonding metal layer are patterned and etched to form isolated light-emitting units.

[0083] S22: Generate a transparent conductive layer on the outer periphery of the light-emitting unit, the transparent conductive layer includes: a first conductive layer, a second conductive layer and a third conductive layer, the first conductive layer is covered on the outer periphery of the side surface of the light-emitting unit away from the driving backplane, the second conductive layer is covered on the outer periphery of the side wall of the light-emitting unit, and the third conductive layer is covered on the outer periphery of the side surface of the driving backplane facing the light-emitting unit.

[0084] Specifically, a transparent conductive film is deposited by sputtering, evaporation, etc. to generate a transparent conductive layer around the light-emitting unit. The transparent conductive layer protrudes onto the driving backplane through the first conductive layer, the second conductive layer and the third conductive layer.

[0085] Furthermore, before step S22, the following steps are also included: passivating the sidewalls and surfaces of the light-emitting unit and the surface of the driving backplane to form a passivation layer; removing the passivation layer corresponding to the top surface of a portion of the light-emitting unit. That is, after the light-emitting unit is passivated, a patterned opening is performed to expose the N-type ohmic contact layer in the light-emitting unit for ohmic contact, and then a transparent conductive layer is prepared, and the transparent conductive layer is connected to the N-type ohmic contact layer.

[0086] For example, Figure 4 As shown, a transparent conductive layer 40 is grown on the light emitting unit 30 which has been passivated and protected by the passivation layer 60 . The transparent conductive layer 40 is entirely protruded on the driving backplane 10 and contacts the top of the light emitting unit 30 through the opening.

[0087] S23: forming a photoresist layer on a target portion of the conductive layer in the transparent conductive layer, wherein the target portion of the conductive layer includes the first conductive layer and / or the second conductive layer.

[0088] Specifically, a photolithography process is performed on a portion of the transparent conductive layer (i.e., the target portion of the conductive layer), which specifically includes the steps of fumigation, photoresist coating, exposure, development, baking, etc., to prepare a photoresist layer. The photoresist layer can be formed on the first conductive layer, or on the second conductive layer, or on the first conductive layer and the second conductive layer.

[0089] S24: electroplating is performed using the transparent conductive layer as an electroplating seed layer to form a reflective metal structure, wherein the reflective metal structure is covered on the surface of the conductive layer of the transparent conductive layer other than the target conductive layer.

[0090] Specifically, after the patterning of the photoresist layer is completed, the light-emitting unit is subjected to an electroplating process. Since the transparent conductive layer itself is conductive, there is no need to additionally grow an electroplating seed layer before electroplating. During the electroplating process, since the photoresist layer is not conductive, no reflective metal structure is formed on the photoresist layer, while the surface of the transparent conductive layer not covered by the photoresist layer is covered with a reflective metal structure.

[0091] It can be understood that the electroplating process can form a relatively dense metal layer on the surface of the original substrate as a reflective metal structure with excellent surface smoothness and uniformity, and the electroplated metal layer has good adhesion and is not easy to peel off; compared with other metal coating methods such as evaporation, magnetron sputtering, arc ion plating, etc., the electroplating process has the advantages of low cost, easy operation and high production efficiency.

[0092] The material of the photoresist layer includes: positive photoresist; or, negative photoresist. Since the reflective metal structure can be directly formed by electroplating, there is no need to rely on the lift-off process for metal patterning, so the photoresist layer can be made of either positive photoresist or negative photoresist, and the thickness of the photoresist layer does not need to be designed to be greater than the thickness of the reflective metal structure, and only a relatively thin thickness is required to meet the needs of subsequent reflective metal structure patterning.

[0093] In one possible implementation, the target portion of the conductive layer includes a first conductive layer, and the reflective metal structure is a first reflective metal structure, which is tightly disposed on a side surface of the second conductive layer away from the light-emitting unit and a side surface of the third conductive layer away from the driving backplane.

[0094] For example, Figure 5 As shown, the photoresist layer 80 is prepared on the first conductive layer 41, and accordingly, Figure 6As shown, after the electroplating is completed, the reflective metal structure 50 is closely arranged on the surface of the second conductive layer 41 and the third conductive layer 43, and only a thin metal layer is required to achieve the side wall reflection effect. In another possible implementation, the target portion conductive layer includes a first conductive layer and a second conductive layer, and the reflective metal structure is a second reflective metal structure, and the second reflective metal structure is stacked on a side surface of the third conductive layer away from the driving backplane.

[0095] For example, Figure 7 As shown, the photoresist layer 80 is prepared on the first conductive layer 41 and the second conductive layer 42, and the top height of the photoresist layer 80 is not lower than the top height of the reflective metal structure 50 prepared subsequently. Figure 8 As shown, after the electroplating is completed, the reflective metal structure 50 is stacked on the surface of the third conductive layer 43, the reflective metal structure 50 is spaced a certain distance from the side wall of the light-emitting unit 30, and the top height of the reflective metal structure 50 is not lower than the top height of the light-emitting unit 30, while reflecting the side light of the light-emitting unit 30 and preventing light crosstalk, the front light intensity is improved.

[0096] S25: removing the photoresist layer.

[0097] Specifically, after the electroplating process is completed, the photoresist layer is removed by wet degumming with a degumming liquid or dry degumming with a dry degumming machine, and the desired reflective metal structure morphology can be obtained after completion. Among them, for reflective metal structures of different metal materials, the degumming liquid used in wet degumming includes but is not limited to acetone, isopropyl alcohol, EKC, etc.; the gas used in dry degumming includes but is not limited to O2, Ar, NH3, H2O, etc. This application does not limit the specific materials and other process parameters used in the degumming process.

[0098] For example, Figure 6 The structure shown in FIG. 1 is removed by removing the photoresist layer 80, and the structure shown in FIG. Figure 1 The reflective metal structure 50 shown is close to the light emitting unit 30; Figure 8 The structure shown in FIG. 1 is removed by removing the photoresist layer 80, and the structure shown in FIG. Figure 2 The reflective metal structure 50 is shown to be spaced a certain distance from the sidewall of the light emitting unit 30 .

[0099] In summary, the method for preparing a micro-display luminous pixel provided in the embodiment of the present application is characterized in that a transparent conductive layer protruding in a direction away from a driving backplane is covered on the outer periphery of the light-emitting unit, and a reflective metal structure is further electroplated on a portion of the surface of the transparent conductive layer so that the reflective metal structure surrounds the side wall of the light-emitting unit, thereby achieving the effect of reducing optical crosstalk. On the one hand, the reflective metal structure is prepared by electroplating, and there is no need for a gold tearing process, and the photolithography requirements are low, thereby avoiding the problems of photolithography difficulties, patterning anomalies, and metal fractures that occur under small sizes. On the other hand, compared with the traditional electroplating process, the reflective metal structure is formed by direct electroplating on the transparent conductive layer, and there is no need for additional growth of the reflective metal structure and removal of the electroplating seed layer, thereby optimizing the process flow of the reflective metal structure.

[0100] Furthermore, the reflective metal structure can be designed as a first reflective metal structure that is closely attached to the side wall of the light-emitting unit, which can effectively limit the light emitted from the side wall and prevent light crosstalk between pixels.

[0101] Furthermore, the reflective metal structure can be designed as a second reflective metal structure that is spaced a certain distance from the side wall of the light-emitting unit. While preventing light crosstalk, it can also reflect the side wall light to the front light-emitting surface of the light-emitting unit above, thereby increasing the front light intensity.

[0102] The present application also provides a micro display screen 200, such as Fig. 9 As shown, the micro display screen 200 includes:

[0103] The micro display screen back panel 300 includes at least two driving circuits, an input interface and an output interface;

[0104] A display area 400, which is disposed on the micro display back panel 300, and includes at least two display modules as in the above embodiment, and the at least two display modules are arranged in an array;

[0105] The peripheral common cathode 500 is electrically connected to each display module respectively, so that the entire micro display screen 200 has a common cathode.

[0106] The external IO interface 600 is located at any position of the micro display screen back panel 300 .

[0107] Furthermore, this embodiment does not limit the arrangement direction of each display module adjacently arranged in an array in the micro display screen 200 .

[0108] For the specific structure and corresponding technical effects of the micro display screen in this embodiment, please refer to the relevant description of the above embodiment, and no further detailed description will be given in this embodiment.

[0109] All of the above-mentioned optional technical solutions can be arbitrarily combined to form optional embodiments of the present utility model, that is, any multiple embodiments can be combined to meet the needs of different application scenarios. They are all within the protection scope of this application and will not be described one by one here.

[0110] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro display luminous pixel, characterized in that: The micro display luminous pixel comprises: A driving back plate having an anode contact therein; A display module is arranged on the driving backplane, and the display module includes a light-emitting unit that is electrically connected to the anode contact, and the outer periphery of the light-emitting unit is covered with a transparent conductive layer that protrudes in a direction away from the driving backplane, and a reflective metal structure is electroplated on a part of the surface of the transparent conductive layer so that the reflective metal structure surrounds the side wall of the light-emitting unit.

2. The micro display luminescent pixel according to claim 1, characterized in that: The transparent conductive layer comprises: A first conductive layer, the first conductive layer is coated on the outer periphery of a surface of the light emitting unit away from the driving backplane; A second conductive layer, the second conductive layer is coated on the outer periphery of the side wall of the light emitting unit; A third conductive layer, the third conductive layer is coated on the outer periphery of a surface of the driving back plate facing the light-emitting unit; The reflective metal structure is electroplated on the second conductive layer and / or the third conductive layer.

3. The micro display luminescent pixel according to claim 2, characterized in that: The reflective metal structure comprises: The first reflective metal structure is closely disposed on a side surface of the second conductive layer away from the light emitting unit and a side surface of the third conductive layer away from the driving backplane.

4. The micro display luminescent pixel according to claim 3, characterized in that: The thickness of the first reflective metal structure is within a range of 10 to 1000 nm.

5. The micro display luminescent pixel according to claim 2, characterized in that: The reflective metal structure comprises: A second reflective metal structure is stacked and arranged on a surface of a side of the third conductive layer away from the driving back plate.

6. The micro display luminescent pixel according to claim 5, characterized in that: The top height of the second reflective metal structure is not lower than the top height of the light emitting unit, and the height of the protruding portion of the second reflective metal structure relative to the top of the light emitting unit does not exceed 1 / 3 of the overall height of the light emitting unit.

7. The micro display luminescent pixel according to claim 5, characterized in that: The distance between the second reflective metal structure and the light emitting unit is between 1 / 4 and 1 / 2 of the diameter of the light emitting unit.

8. The micro display luminescent pixel according to claim 5, characterized in that: The light-emitting unit includes a bonding metal layer and a compound pixel layer stacked from bottom to top, and the surface size of the bonding metal layer is larger than the surface size of the compound pixel layer; The second reflective metal structure is also stacked on a portion of a side surface of the second conductive layer corresponding to the bonding metal layer.

9. The micro display luminescent pixel according to claim 1, characterized in that: A passivation layer is provided between the light emitting unit and the transparent conductive layer, and the passivation layer covers a portion of the surface of the light emitting unit away from the driving backplane, the side wall of the light emitting unit, and a surface of the driving backplane facing the light emitting unit.

10. The micro display luminescent pixel according to claim 1, characterized in that: The reflective metal structure comprises at least one of the following layers: An adhesive layer for achieving the adhesion capability of the reflective metal structure; A reflective layer, used to realize the light reflection capability of the reflective metal structure; Protective layer used to protect the metal in reflective metal structures.

11. A micro display screen, characterized in that: The micro display screen comprises: A micro display screen backplane, the micro display screen backplane comprising a driving circuit, an input interface and an output interface; A display area, the display area is arranged on the back panel of the micro display screen, and the display area includes at least two display modules included in the micro display luminous pixel according to any one of claims 1 to 10, and at least two of the display modules are arranged in an array; A peripheral common cathode is electrically connected to each of the display modules.

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