Display module, preparation method thereof and electronic equipment

Abstract

The invention provides a display module, a preparation method thereof and electronic equipment, relates to the technical field of display, and aims to solve the problems of low imaging quality and the like of the display module. The display module comprises a driving substrate, a conductive grid, a transparent conductive layer and a plurality of miniature light-emitting diodes, the driving substrate comprises a plurality of first electrode contacts and a plurality of second electrode contacts, the miniature light-emitting diodes comprise first electrodes and second electrodes, and the miniature light-emitting diodes correspond to the first electrode contacts one to one. The first electrodes of the micro light-emitting diodes are electrically connected with the corresponding first electrode contacts; the conductive grid is electrically connected with the second electrode contact; the transparent conductive layer covers the plurality of micro light emitting diodes and the conductive grid, the second electrodes of the micro light emitting diodes are electrically connected with the conductive grid through the transparent conductive layer, and the resistivity of the material of the conductive grid is smaller than that of the material of the transparent conductive layer.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a display module, a preparation method thereof, and an electronic device. Background Art

[0002] With the development of microfabrication technology, light-emitting diode (LED) light chips have gradually penetrated from the lighting field to the display field. Micro-LED display technology is a self-luminous display technology. Micro light-emitting diodes, also known as micron-scale light-emitting diodes, are formed by integrating arrayed micron-scale LED units (also referred to as LED units) on a driving substrate with active driving functions. The lower electrode of the microLED forms an electrical connection with the driving substrate, and the upper electrode is made of a transparent conductive material to form an electrical connection with the common electrode and the driving backplane. The transparent conductive material used for the upper electrode has a low conductivity, resulting in a relatively serious voltage drop (IR droop) in a high-resolution display screen, which affects the display quality. Summary of the Invention

[0003] This application provides a display module, a preparation method thereof, and an electronic device, which are used to improve problems such as low imaging quality of the display module.

[0004] In a first aspect, an embodiment of this application provides a display module. The display module includes a driving substrate, a plurality of micro light-emitting diodes, a conductive grid, and a transparent conductive layer. The driving substrate includes a plurality of first electrode contacts and second electrode contacts, and the first electrode contacts and the second electrode contacts are used to form a driving circuit with the micro light-emitting diodes; a plurality of micro light-emitting diodes, each micro light-emitting diode includes a first electrode and a second electrode, and the plurality of micro light-emitting diodes correspond to the plurality of electrode contacts one by one. The first electrode of the micro light-emitting diode is electrically connected to the electrode contact; a conductive grid, the conductive grid includes a plurality of grids, the micro light-emitting diodes correspond to the grids, and the conductive grid is electrically connected to the second electrode contact; the transparent conductive layer covers the plurality of micro light-emitting diodes and the conductive grid, and the second electrode of the micro light-emitting diode is electrically connected to the conductive grid through the transparent conductive layer. The resistivity of the material of the conductive grid is less than the resistivity of the material of the transparent conductive layer.

[0005] The display module provided by the embodiment of this application is provided with a conductive grid. The conductive grid is electrically connected to the transparent conductive layer and the common electrode. The conductive grid is made of a material with good conductivity and has a lower resistance than the transparent conductive layer. The current of the micro light-emitting diode can reach the nearest conductive grid through the transparent conductive layer and then flow to the common electrode through the conductive grid to form a circuit, instead of flowing to the common electrode completely through the transparent conductive layer. This can avoid the voltage drop problem caused by the large resistance of the transparent conductive layer and improve the imaging quality.

[0006] In a possible implementation, a common electrode is further provided on the driving substrate. The common electrode is in contact with the second electrode contact and the conductive grid. The conductive grid is electrically connected to the second electrode contact through the common electrode. In this way, the first electrode of the micro light-emitting diode is electrically connected to the first electrode contact on the driving substrate, and the second electrode of the micro light-emitting diode can be sequentially connected to the second electrode contact through the transparent conductive layer, the conductive grid, and the common electrode.

[0007] In a possible implementation, the conductive grid is electrically connected to the second electrode contact through the internal circuit of the driving substrate. In this way, the first electrode of the micro light-emitting diode is electrically connected to the first electrode contact on the driving substrate, and the second electrode of the micro light-emitting diode can be sequentially connected to the second electrode contact through the transparent conductive layer, the conductive grid, and the internal circuit of the driving substrate.

[0008] In a possible implementation, a height control layer is further provided on the driving substrate, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer. In the embodiment of the present application, the height control layer is provided to make the upper surface of the micro light-emitting diode flush with the upper surface of the height control layer, and the height of the micro light-emitting diode is precisely controlled by the height control layer to improve the display effect.

[0009] In a possible implementation, the display module further includes a dielectric filling layer. The dielectric filling layer is provided between adjacent micro light-emitting diodes and between the height control layer and the driving substrate. The materials of the height control layer, the dielectric filling layer, and the micro light-emitting diode have different removal rates. By using the different removal rates of the materials of the height control layer, the dielectric filling layer, and the micro light-emitting diode, when the wafer is planarized, the height of the wafer can be stopped at the upper surface of the height control layer, so that the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, and the height of the micro light-emitting diode can be defined by the upper surface of the height control layer and the surface of the driving substrate.

[0010] In a possible implementation, multiple micro light-emitting diodes are provided in the area defined by each grid. For example, the display module can be a color display module, and each pixel includes multiple micro light-emitting diodes of different colors. The multiple micro light-emitting diodes included in the pixel can be provided in the area defined by the same grid. The conductive grid can block the light of the micro light-emitting diode to avoid light crosstalk between the micro light-emitting diodes of different pixels.

[0011] In a possible implementation, a micro light-emitting diode is disposed within the area defined by each grid. For example, the display module may be a monochromatic display module, and each pixel includes a monochromatic micro light-emitting diode. The micro light-emitting diode is disposed within the grid, and the conductive grid can block the light of the micro light-emitting diode to prevent crosstalk of the light from different micro light-emitting diodes.

[0012] In a possible implementation, the width of the grid lines of the conductive grid is 10 nm - 1000 nm.

[0013] In a possible implementation, the conductive grid includes a lower surface facing the driving substrate and an upper surface facing away from the driving substrate in a direction perpendicular to the driving substrate. The micro light-emitting diode includes a lower surface facing the driving substrate and an upper surface facing away from the driving substrate in a direction perpendicular to the driving substrate. The distance from the lower surface of the conductive grid to the driving substrate is less than or equal to the distance from the lower surface of the micro light-emitting diode to the driving substrate. The distance from the upper surface of the conductive grid to the driving substrate is greater than or equal to the distance from the upper surface of the micro light-emitting diode to the driving substrate.

[0014] In a possible implementation, the height of the conductive grid in a direction perpendicular to the driving substrate is 1 to 2 times the height of the micro light-emitting diode, which can block the light of the micro light-emitting diode to prevent crosstalk of the light from different micro light-emitting diodes.

[0015] In a possible implementation, the display module further includes a lens layer disposed on the transparent conductive layer. The lens layer may include a plurality of lenses, and the plurality of lenses correspond to the plurality of micro light-emitting diodes one by one. The lenses are used to collimate the light emitted by the micro light-emitting diodes to improve the brightness and imaging quality of the display module.

[0016] In a second aspect, an embodiment of the present application further provides a method for manufacturing a display module. The method includes: forming a plurality of micro light-emitting diodes on a driving substrate. The micro light-emitting diode includes a first electrode and a second electrode disposed opposite to each other. The driving substrate includes a plurality of first electrode contacts and second electrode contacts. The plurality of micro light-emitting diodes correspond to the plurality of first electrode contacts one by one, and the first electrode of the micro light-emitting diode is in contact with the corresponding first electrode contact of the micro light-emitting diode. Forming a common electrode and a conductive grid on the driving substrate. The common electrode is electrically connected to the second electrode contact, and the conductive grid is electrically connected to the common electrode. The conductive grid includes a plurality of grids, and the micro light-emitting diodes correspond to the grids. The micro light-emitting diodes are located within the area defined by their corresponding grids. Forming a transparent conductive layer that covers the plurality of micro light-emitting diodes and the conductive grid. The second electrode of the micro light-emitting diode is electrically connected to the conductive grid through the transparent conductive layer.

[0017] In a possible implementation, before forming the common electrode and the conductive grid on the driving substrate, the method further includes: forming a height control layer on the driving substrate, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer.

[0018] In a possible implementation, forming a height control layer on the driving substrate, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, includes: forming a first dielectric filling layer on the surface of the wafer after forming the micro light-emitting diode; forming a height control layer on the first dielectric filling layer; forming a second dielectric filling layer on the height control layer; performing a planarization process on the wafer after forming the second dielectric filling layer, so that the height of the wafer surface stops at the surface of the height control layer, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, wherein the material of the height control layer has a different removal rate from the material of the micro light-emitting diode and the materials of the first dielectric filling layer and the second dielectric filling layer.

[0019] In a possible implementation, forming a common electrode and a conductive grid on the driving substrate, the conductive grid is in contact with the common electrode, includes: forming a grid-shaped trench and a common electrode trench on the surface of the wafer after forming the height control layer, and the grid-shaped trench and the common electrode trench communicate with each other; forming a conductive grid in the grid-shaped trench and forming a common electrode in the common electrode trench. In this way, the conductive grid is electrically connected to the common electrode, and the current of the micro light-emitting diode can be transmitted to the conductive grid through the transparent conductive layer, and then transmitted to the common electrode through the conductive grid, reducing the resistance of the current loop of the micro light-emitting diode and avoiding the voltage drop due to excessive resistance from affecting the display quality.

[0020] In a third aspect, an electronic device is further provided, including a housing and a display module provided in any implementation manner of the first aspect, and the display module is installed on the housing. Description of the Drawings

[0021] Figure 1 Schematic diagram of the electronic device provided in the embodiment of the present application;

[0022] Figure 2 Schematic diagram of a display module provided in the embodiment of the present application;

[0023] Figure 3 Cross-sectional view of a display module provided in the embodiment of the present application;

[0024] Figure 4 Schematic diagram of another display module provided in the embodiment of the present application;

[0025] Figure 5 Cross-sectional view of another display module provided in the embodiment of the present application;

[0026] Figure 6 Schematic diagram of the working principle of a display module provided by an embodiment of the present application;

[0027] Figure 7 Schematic diagram of the working principle of another display module provided by an embodiment of the present application;

[0028] Figure 8 Cross-sectional view of another display module provided by an embodiment of the present application;

[0029] Figure 9 Schematic diagram of light crosstalk provided by an embodiment of the present application;

[0030] Figure 10 Schematic diagram of the principle of preventing light crosstalk provided by an embodiment of the present application;

[0031] Figure 11 Schematic diagram of the grid shape of the conductive grid provided by an embodiment of the present application;

[0032] Figure 12 Schematic diagram of the shape of the metal grid provided by an embodiment of the present application;

[0033] Figure 13 Schematic diagram of another display module provided by an embodiment of the present application;

[0034] Figure 14 Cross-sectional view of another display module provided by an embodiment of the present application;

[0035] Figure 15 Cross-sectional view of another display module provided by an embodiment of the present application;

[0036] Figure 16 Schematic flow chart of the preparation method of the display module provided by an embodiment of the present application;

[0037] Figure 17 Schematic flow chart of the preparation method of another display module provided by an embodiment of the present application;

[0038] Figure 18 Schematic flow chart of the preparation method of another display module provided by an embodiment of the present application;

[0039] Figures 19 to 21 Process flow chart of the preparation method of the display module provided by an embodiment of the present application. Detailed implementation manners

[0040] The following will describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. "At least one (item)" or similar expressions below refer to any combination of these items, including any combination of single item (s) or plural items (s). For example, at least one (item) of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0041] In the embodiments of the present application, terms such as "first" and "second" are used to distinguish objects with similar names, functions, or roles. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order. The term "coupled" is used to represent an electrical connection, including being directly connected through a wire or a connection terminal or being indirectly connected through other devices. Therefore, "coupled" should be regarded as a broad sense of electronic communication connection.

[0042] It should be noted that in the present application, words such as "exemplary" or "for example" are used to give examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific way.

[0043] The solution provided by the embodiments of the present application can be applied to electronic devices, such as mobile phones, personal computers (PCs), tablets (pads), smart wearable products (such as smart watches, smart bracelets), virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, vehicle-mounted terminals, displays, and other electronic devices, or can also be any electronic device that needs to be configured with a display module. The specific form of the above-mentioned electronic devices is not particularly limited in the embodiments of the present application.

[0044] Taking an AR head-mounted display device as an electronic device as an example, the AR head-mounted display device can include AR glasses or AR helmets, etc. For the convenience of description, refer to Figure 1 , Figure 1 which shows a schematic diagram of an AR glasses provided by the embodiments of the present application.

[0045] The AR glasses include a frame 101, temple arms 102 and lenses 103. The lenses 103 are mounted on the frame 101, and the temple arms 102 are connected to the frame 101. The temple arms 102 and the frame 101 can be used to wear the AR glasses in front of the user's eyes. A display screen is provided in the temple arms 102, which can display images or other content. The above lenses 103 are waveguide lenses, and the images or other content displayed on the display screen can be transmitted to the lenses 103 through the waveguide for display and form an image in front of the user's eyes.

[0046] Due to the limited space of the AR glasses, the above display screen can be a micro light-emitting diode (Micro LED) display screen. Micro LED is a display device at the micron level, and its size is usually from 0.1 micron to 100 microns. The miniaturization enables Micro LED to have higher luminous brightness, resolution and color saturation, faster display response speed and lower power consumption. The emergence of Micro LED display technology makes it possible for the miniaturization and high resolution of AR display devices, VR display devices, near-eye display (NED) and head-up display (HUD) devices, etc.

[0047] Please refer to Figure 2 and Figure 3 , Figure 2 which shows a schematic diagram of a display module 200 provided by an embodiment of the present application. Figure 3 which shows a cross-sectional view of the display module 200 provided by an embodiment of the present application along the Figure 2 B-B' direction in

[0048] The display module 200 includes a driving substrate 210. The driving substrate 210 may include a substrate 211, a driving circuit layer 212 and a protective layer 213 arranged in sequence. The driving circuit layer 212 may include a plurality of driving circuits or driving units for controlling the active driving of Micro LED. The driving circuit usually includes components such as transistors, capacitors and resistors. A second electrode contact 215 and a plurality of first electrode contacts 214 are provided on the surface of the protective layer 213. The first electrode contacts 214 and the second electrode contacts 215 are connected to the driving circuit through vias in the protective layer 213. For example, the first electrode contact 214 may be an anode contact, and the second electrode contact 215 may be a cathode contact.

[0049] The driving substrate 210 can be divided into a light-emitting region and a peripheral region outside the light-emitting region. The light-emitting region can be provided with a plurality of pixel units arranged in an array. Each pixel unit includes one sub-pixel or multiple sub-pixels. Each sub-pixel can include a micro light-emitting diode 220. In some possible implementation manners, the pixel unit can include a red sub-pixel, a green sub-pixel, and a blue sub-pixel, so that color display can be achieved through red, green, and blue color mixing. Of course, in actual applications, the light-emitting color of the sub-pixels in the pixel unit can be designed and determined according to the actual application environment, which is not limited herein.

[0050] Refer to Figure 3 , the micro light-emitting diode 220 includes a first semiconductor layer 221, a light-emitting layer 222, and a second semiconductor layer 223 that are sequentially stacked. Among them, the first semiconductor layer 221 is located on the side close to the driving substrate 210, and the second semiconductor layer 223 is located on the side away from the driving substrate 210. The first semiconductor layer 221 can be P-type doped or N-type doped in a semiconductor material (such as gallium oxide and other materials) so that the first semiconductor layer 221 can provide holes or electrons. The light-emitting layer 222 can adopt a multi-quantum well layer to improve the light-emitting efficiency. The second semiconductor layer 223 can be N-type doped or P-type doped in a semiconductor material (such as gallium nitride and other materials) so that the second semiconductor layer 223 can provide electrons or holes. The first semiconductor layer 221 and the second semiconductor layer 223 are located on both sides of the light-emitting layer 222, and the doping types of the two semiconductor layers are opposite. If the first semiconductor layer 221 is N-type doped, the second semiconductor layer 223 is P-type doped; if the first semiconductor layer 221 is P-type doped, the second semiconductor layer 223 is N-type doped. In specific implementation, both of the above two structures can be applied.

[0051] The micro light-emitting diode 220 may further include an ohmic contact layer 224 in contact with the first semiconductor layer 221. The ohmic contact layer 224 may form the first electrode of the micro light-emitting diode 220. The micro light-emitting diode 220 further includes a second electrode opposite to the first electrode. In some possible implementation manners, a conductive contact layer may be disposed on the second semiconductor layer 223 as the second electrode. Alternatively, in the embodiments of the present application, the transparent conductive layer 240 in contact with the second semiconductor layer 223 may be used as the second electrode of the micro light-emitting diode 220, and a plurality of micro light-emitting diodes 220 may share the same second electrode. In some possible implementation manners, a bonding layer 225 is further disposed between the ohmic contact layer 224 and the driving substrate 210. The bonding layer 225 is used to bond the micro light-emitting diode 220 to the driving substrate 210. In the embodiments of the present application, taking the first semiconductor layer 221 being P-type doped and the second semiconductor layer 223 being N-type doped as an example, in this case, the first electrode of the micro light-emitting diode 220 may be an anode, and the second electrode of the micro light-emitting diode 220 may be a cathode.

[0052] The above-mentioned plurality of first electrode contacts 214 are distributed in the light-emitting area, the second electrode contacts 215 are disposed in the peripheral area, and a common electrode 216 is further disposed on the driving substrate 210. The position of the common electrode 216 corresponds to that of the second electrode contacts 215 and is electrically connected to the second electrode contacts 215. The plurality of first electrode contacts 214 correspond to the plurality of micro light-emitting diodes 220 one by one. The first electrode of each micro light-emitting diode 220 is in contact with the first electrode contact 214 corresponding to the micro light-emitting diode 220 to form an electrical connection. The plurality of micro light-emitting diodes 220 are electrically connected to the common electrode 219 through their shared second electrode, and thus are electrically connected to the second electrode contacts 215. In this way, the micro light-emitting diode 220 is electrically connected to the first electrode contacts 214 and the second electrode contacts 215 to form a driving circuit.

[0053] For example, a transparent conductive layer 240 covers multiple micro light-emitting diodes 220 in the light-emitting region. The second semiconductor layer 223 of the micro light-emitting diode 220 forms an electrical connection with the transparent conductive layer 240. The transparent conductive layer 240 can form a common second electrode for the multiple micro light-emitting diodes 220, or it can be considered that the portion of the transparent conductive layer 240 in contact with each micro light-emitting diode forms the second electrode of that micro light-emitting diode. A common electrode 216 is provided in the peripheral region of the driving substrate 210. For example, the common electrode 216 can be provided above the second electrode contact 215, and the common electrode 216 is electrically connected to the second electrode contact 215. The transparent conductive layer 240 can be connected to the common electrode 216 in the peripheral region. For example, the transparent conductive layer 240 can simultaneously cover the multiple micro light-emitting diodes in the light-emitting region and the common electrode in the peripheral region. Current can flow into the first electrode of the micro light-emitting diode 220 from the first electrode contact 214 of the driving substrate 210. After passing through the micro light-emitting diode 220, it flows out from the second electrode of the micro light-emitting diode 220, flows through the transparent conductive layer 240 to the common electrode 216, and finally reaches the second electrode contact 215 to form a driving loop. The micro light-emitting diode 220 can emit light and display when current flows through it. By adjusting the magnitude or on-time of the current flowing through the micro light-emitting diode 220, the gray scale, brightness, etc. displayed by the micro light-emitting diode 220 can be adjusted.

[0054] Considering the light extraction effect, the transparent conductive layer 240 can be made of a material with high visible light transmittance, such as indium tin oxide (ITO). Materials with high visible light transmittance usually have relatively high resistance. The current of the second electrode of the micro light-emitting diode 220 is transmitted to the common electrode 216 through the transparent conductive layer 240. The material of the transparent conductive layer 240 (e.g., ITO) has a relatively large resistance, and the lengths of the paths for the currents of the micro light-emitting diodes 220 at different positions to reach the common electrode 216 are different. For example, refer to Figure 3 , Figure 3 shows Figure 2Schematic cross-sectional view along the B-B' direction. The current path between the micro light-emitting diode 220 close to the common electrode 216 and the common electrode 216 is shorter, while the current path between the micro light-emitting diode 220 far from the common electrode 216 and the common electrode 216 is longer. The path lengths of the current loops of the micro light-emitting diodes 220 at different positions are different, and the resistivity of the transparent conductive layer 240 is relatively high, which leads to a certain voltage drop (IR drop) problem. Since the Micro LED display panel drives the micro light-emitting diodes to emit light by current, and the micro light-emitting diodes are sensitive to weak changes in current, small current changes will cause large brightness changes. The current path between the micro light-emitting diodes close to the common electrode 216 and the common electrode 216 is shorter, with a smaller resistance and a smaller voltage drop. Therefore, the display brightness of these micro light-emitting diodes is less affected. However, the current path between the micro light-emitting diodes far from the common electrode 216 and the common electrode 216 is longer, with a larger resistance and a larger voltage drop, resulting in a lower display brightness and causing brightness differences among the micro light-emitting diodes at different positions.

[0055] The current loops of the micro light-emitting diodes at different positions flow through different lengths of paths in the transparent conductive layer. The resistivity of the material of the transparent conductive layer is relatively high. Therefore, the current loop with a longer path in the transparent conductive layer has a larger resistance, and the current loop with a shorter path in the transparent conductive layer has a smaller resistance. The difference in resistance sizes will cause different current sizes in different loops, ultimately resulting in display brightness differences.

[0056] To improve the above problems, the embodiment of the present application provides another display module. A conductive grid is provided on the driving substrate. The current of each pixel does not flow to the common electrode through the transparent conductive layer, but can flow through the transparent conductive layer to the conductive grid, and then through the conductive grid to the second electrode contact to form a loop. The resistance of the conductive grid is smaller than the resistance of the material of the transparent conductive layer. Such a solution is equivalent to replacing the material of the transparent conductive layer with a higher resistivity in the current loop of the micro light-emitting diode with the material of the conductive grid, which can reduce the resistance of the current loop of the micro light-emitting diode and avoid the influence of IR drop on the imaging quality.

[0057] Refer to Figure 4 and Figure 5 , Figure 4 shows a schematic structural diagram of the display module 300 provided by the embodiment of the present application. Figure 5 shows Figure 4Cross-sectional view in the direction of B-B`, showing that the module 300 includes a driving substrate 310, and a conductive grid 330, a transparent conductive layer 340, and a plurality of micro light-emitting diodes 320 disposed on the driving substrate 310. The driving substrate 310 includes a light-emitting area and a peripheral area outside the light-emitting area. A plurality of first electrode contacts 314 are provided in the light-emitting area, and a second electrode contact 315 is provided in the peripheral area. A common electrode 316 electrically connected to the second electrode contact 314 is further provided on the driving substrate. The plurality of micro light-emitting diodes 320 are arranged in the light-emitting area, and the plurality of micro light-emitting diodes 320 correspond to the plurality of electrode contacts 314 one by one. The micro light-emitting diode 320 includes a first electrode and a second electrode. In this embodiment, the first electrode is the electrode facing the driving substrate 310, and the second electrode is the electrode away from the driving substrate 310. The first electrode of the micro light-emitting diode 320 contacts the corresponding electrode contact 314 of the micro light-emitting diode 320 to form an electrical connection.

[0058] The conductive grid 330 is disposed on the driving substrate 310. The conductive grid 330 is a grid formed by a plurality of conductive grid lines intersecting and connecting. The conductive grid 330 includes a plurality of grids. The micro light-emitting diodes 320 correspond to the grids. The micro light-emitting diodes 320 can be disposed in the area of the driving substrate 310 defined by the grids. The conductive grid 330 located in the peripheral area contacts and is electrically connected to the common electrode 316.

[0059] The transparent conductive layer 340 covers the conductive grid 330 located in the light-emitting area. The transparent conductive layer 340 forms an electrical connection with the conductive grid 330. The second electrode of the micro light-emitting diode 320 contacts the transparent conductive layer 340 (or it can be considered that the part of the transparent conductive layer 340 in contact with the micro light-emitting diode forms the second electrode of the micro light-emitting diode 320). The projection of the transparent conductive layer 340 on the driving substrate 310 covers the light-emitting area, so as to ensure that the transparent conductive layer 340 forms an electrical connection with all the micro light-emitting diodes 320, and the transparent conductive layer 340 forms an electrical connection with the conductive grid 330. That is, in the embodiment of the present application, the conductive grid 330 is electrically connected to the common electrode 316, and the second electrode of the micro light-emitting diode 220 can be electrically connected to the conductive grid 330 through the transparent conductive layer 340, that is, electrically connected to the common electrode 316

[0060] In some embodiments, the driving substrate 310 may include a substrate 311, a driving circuit layer 312, and a protective layer 313 disposed in sequence. The driving circuit layer 312 may include a plurality of driving circuits or driving units for actively driving the Micro LEDs. The driving circuits generally may include complementary metal oxide semiconductor (CMOS) devices or TFT devices, etc. A plurality of first electrode contacts 314 and second electrode contacts 315 are disposed on the surface of the protective layer 313. The first electrode contacts 314 and the second electrode contacts 315 are connected to the driving circuit layer 312 through vias in the protective layer 313. For example, the first electrode contact 314 may be an anode contact, and the second electrode contact 315 may be a cathode contact. A common electrode 316 corresponding to the position of the second electrode contact 315 is further disposed on the driving substrate 310, and the common electrode 316 is electrically connected to the second electrode contact. Among them, the material of the substrate 311 may be a semiconductor material such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, indium phosphide, etc., or a non-conductive material such as glass, plastic, or sapphire wafer.

[0061] The driving substrate 310 can provide driving current for each micro light-emitting diode 320. The current flows into the first electrode of the micro light-emitting diode 320 from the first electrode contact 314 of the driving substrate 310, flows out from the second electrode of the micro light-emitting diode 320, and finally reaches the second electrode contact 315 on the driving substrate 310 to form a loop.

[0062] In a possible implementation, please refer to Figure 4 , a plurality of pads 350 are further disposed on the driving substrate 310. A part of these pads 350 is electrically connected to the driving circuits in the driving circuit layer 312 for supplying power signals, data signals, etc. to the driving circuits, and another part of the pads 350 can be electrically connected to the second electrode contacts 315 on the driving substrate 310. The first electrode of the micro light-emitting diode 320 is electrically connected to the first electrode contact 314 on the driving substrate 310, that is, electrically connected to the driving circuits in the driving circuit layer 312. The second electrode of the micro light-emitting diode 320 is electrically connected to the common electrode 316, that is, electrically connected to the second electrode contact 315. In a possible implementation, the second electrode contact 315 may be a cathode, and the first electrode contact 314 may be an anode. When a loop is formed among the micro light-emitting diode 320, the first electrode contact 314, and the common electrode 316 (or the second electrode contact 315), the cathode current can be injected into the micro light-emitting diode 320 from the common electrode 316 (or the second electrode contact 315) and recombine with the carriers injected into the micro light-emitting diode 320 from the first electrode contact 314 to emit light.

[0063] In the embodiments of the present application, since a conductive grid 330 is provided on the driving substrate 310, the second electrode of the micro light-emitting diode 320 is electrically connected to the conductive grid 330 through the transparent conductive layer 340, and the conductive grid 330 is electrically connected to the common electrode 316. In this way, after the current flows out from the second electrode of the micro light-emitting diode 320 to the transparent conductive layer 340, it will choose to flow through the conductive grid 330 with a lower resistance to the common electrode 316 to form a loop. The conductive grid 330 has good conductivity and small resistance, so that problems such as IR drop caused by the large resistance of the transparent conductive layer 340 can be overcome.

[0064] Combined with Figure 6 and Figure 7 , Figure 6 shows a schematic diagram of a display module. Figure 7 shows a schematic diagram of another display module. Figure 6 shows the micro light-emitting diodes 220-1 and 220-2, where the micro light-emitting diode 220-1 is farther from the common electrode 216, and the micro light-emitting diode 220-2 is closer to the common electrode 216. Figure 7 shows the micro light-emitting diodes 320-1 and 320-2, where the micro light-emitting diode 320-1 is farther from the common electrode 316, and the micro light-emitting diode 320-2 is closer to the common electrode 316.

[0065] In the case where no conductive grid is provided, for example, combined with Figure 6 the a and b figures in, the path of the current loop of the micro light-emitting diodes (220-1, 220-2) is as follows: it flows into the first electrode of the micro light-emitting diodes (220-1, 220-2) through the first electrode contact 214, flows out from the second electrode of the micro light-emitting diodes (220-1, 220-2) to the transparent conductive layer 240, and flows through the transparent conductive layer 240 to the common electrode 216 to form a loop.

[0066] In the case where a conductive grid is provided, combined with Figure 7 the a and b figures in, the path of the current loop of the micro light-emitting diodes (320-1, 320-2) is as follows: it flows into the first electrode of the micro light-emitting diodes (320-1, 320-2) through the first electrode contact 314, flows out from the second electrode of the micro light-emitting diodes (320-1, 320-2) to the transparent conductive layer 340, flows through the transparent conductive layer 340 to the nearest conductive grid 330, and flows through the conductive grid 330 to the common electrode 316 to form a loop.

[0067] It can be seen from this that combined with Figure 6, in the case where the conductive grid is not provided, in the current path of the micro light-emitting diode, the transparent conductive layer occupies a relatively large part, so the resistance of the loop is relatively large; after the conductive grid is provided, in the current path of the micro light-emitting diode, the transparent conductive layer only occupies a very small part, and the conductive grid occupies a relatively large part, so the resistance is relatively small, which can avoid problems such as the degradation of display quality caused by IR Drop.

[0068] In addition, for the micro light-emitting diodes 320-1 and 320-2 at different positions, although the lengths of their current paths are different because their distances from the common electrode 316 are different, the difference in the length of the current path is mainly reflected in the part occupied by the conductive grid, and the conductive grid is made of a conductive metal material with low resistance, so such a difference will not result in an obvious resistance change; in the case where the grid pitch of the conductive grid is close, for the micro light-emitting diodes 320-1 and 320-2 at different positions, the parts of the transparent conductive layer 340 in their current paths are similar, that is, the distance from the second electrode of the micro light-emitting diode to the nearest conductive grid, which makes the resistances of the current loops of the micro light-emitting diodes at different positions close and can avoid differences in display brightness.

[0069] In some embodiments of the present application, the resistivity of the material of the conductive grid is lower than the resistivity of the material of the transparent conductive layer. For example, the conductive grid can be made of a conductive metal material, such as a single-layer metal, a stacked metal, or a stacked structure of a dielectric and a metal, such as copper (Cu), aluminum (Al), tungsten (W), titanium nitride (TiN), tantalum nitride (TaN), titanium tungsten alloy (TiW), a stacked structure of titanium tungsten alloy-aluminum-titanium tungsten alloy (TiW / Al / TiW), a stacked structure of titanium nitride-aluminum-titanium nitride (TiN / Al / TiN), a stacked structure of titanium tungsten alloy-aluminum-titanium nitride (TiW / Al / TiN), a stacked structure of titanium tungsten alloy-tungsten-titanium nitride (TiW / W / TiN), etc.

[0070] In some embodiments of the present application, the conductive grid 330 can be disposed on the driving substrate 310 and electrically connected to the common electrode 316, and the conductive grid 330 is electrically connected to the second electrode contact 315 through the common electrode 316. In some other possible implementation manners of the present application, for example, refer to Figure 8 , the conductive grid 330 can be electrically connected to the second electrode contact 315 through the internal trace of the driving substrate 310. In addition, in some other embodiments of the present application, the conductive grid 330 can also be electrically connected to the second electrode contact 315 in other ways to reduce the voltage drop generated by the transparent conductive layer in the driving loop of the micro light-emitting diode.

[0071] Since Micro LED is a self - emitting device and its light - emitting shape is a Lambertian body, as Figure 9 shown, that is, the brightness of the light emitted by the Micro LED in all directions is the same, which will cause light crosstalk between pixels. To avoid this problem, the embodiments of the present application can limit the light - emitting direction of each micro - light - emitting diode through a conductive grid to avoid light crosstalk between pixels.

[0072] In some embodiments of the present application, the conductive grid can be an opaque conductive grid. Combining Figure 10 , the height of the conductive grid in the direction perpendicular to the driving substrate is not less than the height of the micro - light - emitting diode. For example, combining Figure 10 with figure a in it, both the conductive grid 330 and the micro - light - emitting diode 320 include an upper surface and a lower surface. The lower surface 330B of the conductive grid 330 is not higher than the lower surface 320B of the micro - light - emitting diode 320, or it can be said that the distance from the lower surface 330B of the conductive grid 330 to the driving substrate 310 is less than or equal to the distance from the lower surface 320B of the micro - light - emitting diode 320 to the driving substrate 310, and the upper surface 330A of the conductive grid 330 is not lower than the upper surface 320A of the micro - light - emitting diode 320, or it can be said that the distance from the upper surface 330A of the conductive grid 330 to the driving substrate 310 is greater than or equal to the distance from the upper surface of the micro - light - emitting diode 320 to the driving substrate 310. In other words, the lowest point of the conductive grid 330 in the direction perpendicular to the driving substrate is not higher than the lowest point of the micro - light - emitting diode 320, and the highest point of the conductive grid 330 in the direction perpendicular to the driving substrate is not lower than the highest point of the micro - light - emitting diode 320. Combining Figure 10 with figure b in it, such a setting method can use the conductive grid 330 to block the light emitted by the micro - light - emitting diode 320 from scattering to the adjacent micro - light - emitting diode 320, avoiding light crosstalk between different pixels.

[0073] In some embodiments of the present application, the height L1 of the conductive grid 330 is not less than the height L2 of the micro - light - emitting diode 320, and the lowest point of the conductive grid 330 in the direction perpendicular to the driving substrate is lower than the lowest point of the micro - light - emitting diode 320, which can avoid the light emitted by the micro - light - emitting diode 320 from leaking from the bottom of the micro - light - emitting diode 320 and causing crosstalk. The highest point of the conductive grid 330 in the direction perpendicular to the driving substrate is higher than the highest point of the micro - light - emitting diode 320, which can avoid the light at the top of the micro - light - emitting diode 320 from generating crosstalk in the horizontal direction.

[0074] In addition, combining Figure 10In FIG. b, the conductive grid 330 can also have a certain reflection effect on the light emitted by the micro light-emitting diodes 320, and can gather and / or collimate the light emitted by the micro light-emitting diodes 320, thereby improving the luminous brightness of the display module as a whole.

[0075] In some embodiments of the present application, the height L1 of the conductive grid 330 in the direction perpendicular to the driving substrate is 1 to 2 times the height L2 of the micro light-emitting diode 320. When the height L1 of the conductive grid 330 is the same as the height L2 of the micro light-emitting diode 320, in order to ensure the anti-crosstalk effect, it is necessary to make the upper surface 330A of the conductive grid 330 flush with the upper surface 320A of the micro light-emitting diode 320, and make the lower surface 330B of the conductive grid 330 flush with the lower surface 320B of the micro light-emitting diode 320.

[0076] In some embodiments of the present application, the conductive grid is a conductive grid formed by the intersection of multiple grid lines. The conductive grid includes a plurality of grids, and one or more micro light-emitting diodes can be arranged in the area of the driving substrate defined by each grid. Whether it is one micro light-emitting diode or multiple micro light-emitting diodes here refers to the smallest unit of the LED pixel. For example, in some cases, the display module is a monochromatic display module, and one micro light-emitting diode can form one pixel. In this case, one micro light-emitting diode can be arranged in the area defined by the grid of the conductive grid, and this micro light-emitting diode is connected to the conductive grid through a transparent conductive layer; in other cases, the display module is a color display module, and multiple micro light-emitting diodes are combined to form one pixel. In this case, multiple micro light-emitting diodes can be arranged in the area defined by the grid of the conductive grid, and these micro light-emitting diodes are electrically connected to the conductive grid through a transparent conductive layer. For example, if one pixel includes 2 red sub-pixels, 1 green sub-pixel and 1 blue sub-pixel, then four micro light-emitting diodes such as two red micro light-emitting diodes, one blue micro light-emitting diode and one green micro light-emitting diode can be arranged in the grid hole of the conductive grid.

[0077] In some embodiments of the present application, the conductive grid includes a plurality of grid holes, as Figure 10 shown in FIG. b, the side wall of the grid hole can be perpendicular to the driving substrate, or, referring to Figure 10 the side wall of the grid shown in FIG. c, it can also form a certain angle with the driving substrate. For example, the side wall of the grid hole is set at an obtuse angle with the driving substrate, so that the light emitted by the micro light-emitting diode can be reflected multiple times on the inner wall of the grid hole and finally exit through the opening of the grid hole, which can avoid optical crosstalk between different pixels and improve the luminous brightness.

[0078] In addition, referring to Figure 11, the grid shape of the conductive grid may include regular shapes such as triangles, quadrilaterals, hexagons, octagons, circles, or irregular shapes, and can be adjusted accordingly according to the arrangement of the micro light-emitting diodes.

[0079] Combined with Figure 12 , the conductive grid 330 can be a conductive grid formed by the intersection of multiple conductive metal wires. In the embodiments of the present application, the width W of the grid lines of the conductive grid 330 is 10 nm to 1000 nm. Since in Micro LED, the pitch between two adjacent micro light-emitting diodes is often fixed, and the larger the area of the micro light-emitting diode, the higher the luminous brightness. Therefore, in this case, the larger the size of a single micro light-emitting diode, the smaller the distance between the boundaries of two adjacent micro light-emitting diodes, and the smaller the size of the conductive grid that can be set. In the embodiments of the present application, the width W of the grid lines of the conductive grid can be 500 nm.

[0080] In some embodiments, please combine Figure 5 , the micro light-emitting diode 320 includes an ohmic contact layer 324, a first semiconductor layer 321, a light-emitting layer 322, and a second semiconductor layer 323 that are sequentially stacked. The first semiconductor layer 321 is located on the side close to the driving substrate 310, and the second semiconductor layer 323 is located on the side away from the driving substrate 310. In some embodiments of the present application, a bonding layer 325 is further provided between the first semiconductor layer 321 and the driving substrate 310, and the micro light-emitting diode 320 can be adhered or bonded to the driving substrate 310 through the bonding layer 325.

[0081] The first semiconductor layer 321 can be P-type doped or N-type doped in a semiconductor material (such as gallium nitride and other materials) so that the first semiconductor layer 321 can provide holes or electrons. The second semiconductor layer 323 can be N-type doped or P-type doped in a semiconductor material (such as gallium nitride and other materials) so that the second semiconductor layer 323 can provide electrons or holes.

[0082] The first semiconductor layer 321 and the second semiconductor layer 323 are located on both sides of the light-emitting layer 322 in the direction perpendicular to the driving substrate 310, and the doping types of the two semiconductor layers are opposite. If the first semiconductor layer 321 is N-type doped, the second semiconductor layer 323 is P-type doped; if the first semiconductor layer 321 is P-type doped, the second semiconductor layer 323 is N-type doped.

[0083] The micro light-emitting diode 320 may further include an ohmic contact layer 324 in contact with the first semiconductor layer 321. The ohmic contact layer 324 can improve the conductivity between the first semiconductor layer 321 and the driving substrate 310, and in the embodiments of the present application, the ohmic contact layer 324 can form the first electrode of the micro light-emitting diode 320; the micro light-emitting diode 320 further includes a second electrode opposite to the first electrode. In a possible implementation, a conductive contact layer (not shown in the figure) may be provided on the second semiconductor layer 323 as the second electrode of the micro light-emitting diode 320, or in the embodiments of the present application, the transparent conductive layer 340 in contact with the second semiconductor layer 323 can be used as the second electrode of the micro light-emitting diode 320, and a plurality of micro light-emitting diodes 320 can share the same second electrode.

[0084] In some embodiments of the present application, a bonding layer 325 is further provided between the ohmic contact layer 324 and the driving substrate 310, and the bonding layer 325 is used to bond the micro light-emitting diode 320 to the driving substrate 310.

[0085] In the embodiments of the present application, the first semiconductor layer 321 is taken as P-type doped and the second semiconductor layer 323 is taken as N-type doped as an example. On this basis, the first electrode of the micro light-emitting diode 320 can be an anode, and an anode voltage is applied to the first semiconductor layer 321; the second electrode of the micro light-emitting diode 320 can be a cathode, and a cathode voltage is applied to the second semiconductor layer 323.

[0086] In some cases, the micro light-emitting diode 320 is also referred to as a micro light-emitting diode mesa. The cross-sectional shape of each micro light-emitting diode 320 can be a trapezoidal structure, that is, the side wall of the micro light-emitting diode 320 can be an inclined surface, and the angle between the side wall of the micro light-emitting diode 320 and the upper surface can be an obtuse angle, so as to improve the light condensing effect of the micro light-emitting diode. Or, in some possible implementations, the micro light-emitting diode can also be a columnar structure. At this time, the angle between the side wall of the micro light-emitting diode and the upper surface of the micro light-emitting diode is a right angle.

[0087] In some embodiments, a passivation layer can be provided on the side wall of the micro light-emitting diode to prevent etching damage to the micro light-emitting diode during the preparation process. The material of the passivation layer can generally be made of alumina, silicon oxide and other materials. A filling layer is provided between adjacent micro light-emitting diodes and on the surface of the driving substrate.

[0088] Combined Figure 13 and Figure 14 , Figure 14 shows Figure 13Cross-sectional view along the B-B` direction. The conductive grid 330 is disposed in the light-emitting area and the peripheral area of the driving substrate 310. Micro light-emitting diodes 320 are disposed in the grid holes of the light-emitting area, and a height control layer 360 is disposed in the grid holes of the peripheral area. The material of the height control layer 360 has a different removal rate from the material of the micro light-emitting diode 320, the material of the filling layer, etc. The height control layer 360 is used to control the mesa height of the micro light-emitting diode 320. For example, the upper surface of the micro light-emitting diode 320 is flush with the upper surface of the height control layer 360, or it can be considered that the distance between the upper surface of the height control layer and the surface of the driving substrate 310 is the height of the micro light-emitting diode 320.

[0089] In the display module 200 provided by the embodiment of the present application, in the case where the height control layer is not provided, when planarizing the surface of the wafer, the height of the micro light-emitting diode can only be controlled according to experience. During the planarization process, the mesa height cannot be accurately controlled, and it may be over-planarized, resulting in too low a height of the micro light-emitting diode. In the display module 300 provided by the embodiment of the present application, a filling layer is disposed between adjacent micro light-emitting diodes 320, a filling layer is disposed in the peripheral area outside the light-emitting area, and a height control layer 360 is disposed on the filling. In this way, when planarizing the surface of the wafer by using processes such as CMP, since the material of the height control layer 360 has a different removal rate from the material of the micro light-emitting diode 320, the material of the filling layer, etc., the height of the wafer can be stopped at the upper surface of the height control layer 360 during the planarization process, so that the height of the micro light-emitting diode 320 can be accurately controlled.

[0090] In some other possible implementation manners, please refer to Figure 15 , the display module 300 further includes a lens layer 370. The lens layer 370 is disposed on the transparent conductive layer 340. The lens layer 370 includes a plurality of lenses, and the plurality of lenses correspond to the plurality of micro light-emitting diodes one by one. For example, the lens 370-1 corresponds to the micro light-emitting diode 320-1, the lens 370-2 corresponds to the micro light-emitting diode 320-2, and the lens 370-3 corresponds to the micro light-emitting diode 320-3. In some embodiments of the present application, the central axis of the lens may be on the same straight line as the central axis of the micro light-emitting diode. In this way, the lens can be used to collimate the light emitted by the micro light-emitting diode, improving the light-emitting efficiency and light-emitting uniformity of the display module. In other embodiments, the central axis of the lens may not be aligned with the central axis of the micro light-emitting diode or may have a certain angle, and the light-emitting direction of the micro light-emitting diode can be adjusted.

[0091] In addition, the embodiment of the present application also provides a method for manufacturing a display module. Refer to Figure 16 , the method includes:

[0092] S41: Form a plurality of micro light-emitting diodes on the driving substrate. The micro light-emitting diodes include a first electrode and a second electrode which are oppositely arranged. The driving substrate includes a plurality of first electrode contacts and second electrode contacts. The plurality of micro light-emitting diodes correspond to the plurality of first electrode contacts one by one, and the first electrode of the micro light-emitting diode is in contact with the corresponding first electrode contact.

[0093] The plurality of micro light-emitting diodes correspond to the plurality of first electrode contacts one by one, and the first electrode of the micro light-emitting diode is in contact with the corresponding first electrode contact to form an electrical connection. A current signal can be injected into the micro light-emitting diode through the first electrode contact to make the micro light-emitting diode emit light.

[0094] S42: Form a height control layer on the driving substrate. The upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer.

[0095] The removal rate of the material of the height control layer is different from the removal rates of the materials of the micro light-emitting diode and the dielectric filling layer. In the embodiment of the present application, the height control layer is used to precisely control the height of the micro light-emitting diodes in the light-emitting area. For example, the height of the wafer can be stopped at the upper surface of the height control layer, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, so as to achieve precise control of the height of the micro light-emitting diode, thereby improving the light extraction efficiency of the pixel.

[0096] S43: Form a common electrode and a conductive grid on the driving substrate. The conductive grid is in contact with the common electrode. The conductive grid includes a plurality of grids. The micro light-emitting diodes correspond to the grids, and the micro light-emitting diodes are located in the areas defined by their corresponding grids.

[0097] S44: Form a transparent conductive layer. The transparent conductive layer covers the plurality of micro light-emitting diodes and the conductive grid. The second electrode of the micro light-emitting diode is electrically connected to the conductive grid through the transparent conductive layer.

[0098] In the embodiment of the present application, the removal rate of the material of the height control layer is different from the removal rates of the materials of the micro light-emitting diode and the dielectric filling layer, so as to achieve precise control of the height of the micro light-emitting diode. On the basis of Figure 16 Combined with Figure 17 , S42 includes:

[0099] S421: Form a first dielectric filling layer on the surface of the wafer after forming the micro light-emitting diodes.

[0100] S422: Form a height control layer on the first dielectric filling layer.

[0101] S423: Form a second dielectric filling layer on the height control layer.

[0102] S424: After forming the second dielectric filling layer, the wafer is planarized so that the height of the wafer surface stops at the surface of the height control layer, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, wherein the material of the height control layer has a different removal rate from the material of the micro light-emitting diode and the materials of the first dielectric filling layer and the second dielectric filling layer.

[0103] The material of the height control layer has a different removal rate from the material of the micro light-emitting diode and the materials of the first dielectric filling layer and the second dielectric filling layer. In this way, when the wafer is planarized, the height of the wafer can stop at the surface of the height control layer, making the upper surface of the micro light-emitting diode flush with the upper surface of the height control layer.

[0104] In some embodiments of the present application, on the basis of Figure 16 , referring to Figure 18 , S43 includes:

[0105] S431: Form a grid-like trench and a common electrode trench on the wafer surface, and the grid-like trench and the common electrode trench are connected.

[0106] In some embodiments of the present application, the above grid-like trenches are formed in the light-emitting area and the peripheral area, and the common electrode trench is formed in the peripheral area, wherein the second electrode contact is exposed at the bottom of the common electrode trench. The grid-like trench forms a plurality of grids. The above micro light-emitting diodes are arranged in the area defined by the grids in the light-emitting area, and the height control layer is arranged in the area defined by the grids in the peripheral area.

[0107] S432: Form a conductive grid in the grid-like trench and form a common electrode in the common electrode trench.

[0108] The second electrode contact is exposed through the bottom of the common electrode trench. Therefore, the common electrode formed in the common electrode trench is electrically connected to the second electrode contact. And because the grid-like trench and the common electrode trench are connected, after the common electrode is formed in the common electrode trench and the conductive grid is formed in the grid-like trench, the conductive grid contacts the common electrode to form an electrical connection. The conductive grid can be formed of a conductive metal material, such as copper (Cu), aluminum (Al), tungsten (W), titanium nitride (TiN), tantalum nitride (TaN), titanium tungsten alloy (TiW), a stacked structure of titanium tungsten alloy-aluminum-titanium tungsten alloy (TiW / Al / TiW), a stacked structure of titanium nitride-aluminum-titanium nitride (TiN / Al / TiN), a stacked structure of titanium tungsten alloy-aluminum-titanium nitride (TiW / Al / TiN), a stacked structure of titanium tungsten alloy-tungsten-titanium nitride (TiW / W / TiN), etc.

[0109] The following introduces the specific process flow involved in the above steps in conjunction with the drawings.

[0110] Refer to Figure 19 Figure a in, a driving circuit layer 502, a protective layer 503, a bonding layer 504, an ohmic contact layer 505, a first semiconductor layer 506, a light-emitting layer 507, and a second semiconductor layer 508 are formed on a substrate 501, wherein the substrate 501, the driving circuit layer 502, and the protective layer 503 form a driving substrate. The first semiconductor layer 506 may be a P-type semiconductor layer, and the second semiconductor layer 508 may be an N-type semiconductor layer.

[0111] Refer to Figure 19 Figure b in, the parts other than the light-emitting pixels are removed to form a plurality of micro light-emitting diodes or micro light-emitting diode mesa. In some embodiments of the present application, the driving substrate includes a light-emitting region and a peripheral region outside the light-emitting region. The light-emitting region is provided with a plurality of first electrode contacts, such as Figure 19 the first electrode contact 500A shown in Figure b in, and the peripheral region is provided with second electrode contacts, pad contacts, etc., such as Figure 19 the second electrode contact 500B and the pad contact 500C shown in Figure b in. The epitaxial structure above the first electrode contact can be retained, and other structures can be removed by dry etching and retained on the surface of the driving substrate. In this way, a plurality of micro light-emitting diodes corresponding to the first electrode contacts one by one can be formed. The ohmic contact layer 505 can form the first electrode of the micro light-emitting diode, and the first electrode of the micro light-emitting diode contacts the corresponding first electrode contact to form an electrical connection.

[0112] Refer to Figure 19 Figure c in, a passivation layer 509 is deposited on the surface of the driving substrate and the micro light-emitting diodes. For example, the material of the passivation layer 509 can be materials such as alumina and silicon oxide.

[0113] Refer to Figure 19 Figure d in, a first dielectric filling layer 510 is deposited on the passivation layer 509. The material of the first dielectric filling layer 510 can be materials such as silicon oxide.

[0114] Refer to Figure 20 Figure a in, a height control layer 511 is deposited on the first dielectric filling layer 510. The material of the height control layer 511 can be a material with a different removal rate from that of the dielectric filling layer and the micro light-emitting diodes. For example, the material of the height control layer 511 can be silicon nitride. The height control layer 511 is used to control the height of the micro light-emitting diodes. For example, in the embodiments of the present application, the distance between the upper surface of the height control layer 511 and the surface of the driving substrate is the height of the micro light-emitting diodes.

[0115] Or, refer to Figure 20In the figure a, it is also possible not to provide a dielectric filling layer between the height control layer 511 and the driving substrate, and directly deposit the height control layer 511 on the passivation layer 509.

[0116] Refer to Figure 20 In the figure b, a second dielectric filling layer 512 is formed on the height control layer 511. The material of the second dielectric filling layer 512 can be the same as that of the first dielectric filling layer 510. For example, the material of the second dielectric filling layer 512 can be materials such as silicon oxide.

[0117] Refer to Figure 20 In the figure c, the surface of the wafer is planarized. For example, the surface of the wafer is planarized by using a CMP surface planarization process. Since the removal rates of the materials of the height control layer 511, the dielectric filling layer, and the micro light-emitting diodes are different, the structure on the surface of the micro light-emitting diodes can be removed, so that the height of the wafer surface stops at the surface of the height control layer 511, thereby controlling the height of the micro light-emitting diodes. At this time, the upper surface of the micro light-emitting diodes is flush with the upper surface of the height control layer 511, and the distance between the upper surface of the height control layer 511 and the surface of the driving substrate is the height of the micro light-emitting diodes.

[0118] Refer to Figure 20 In the figure d, a grid-shaped trench 513 and a common electrode trench 514 are formed on the surface of the wafer. The second electrode contact can pass through the bottom circuit of the common electrode trench 514, and the grid-shaped trench 513 communicates with the common electrode trench 514. Micro light-emitting diodes are provided in the area defined by the grid formed by the grid-shaped trenches in the light-emitting area, and the above-mentioned first dielectric filling layer 510 and height control layer 511 are provided in the area defined by the grid formed by the grid-shaped trenches in the peripheral area. In some embodiments, a pad trench 515 is also formed corresponding to the position of the pad contact by simultaneous etching.

[0119] Refer to Figure 21 In the figure a, a conductive grid 516 is formed in the grid-shaped trench 513, a common electrode 519 is formed in the common electrode trench 514, the common electrode 519 is electrically connected to the second electrode contact, a pad 520 is formed in the pad trench 515, and the conductive grid 516 is electrically connected to the common electrode 519. The height of the conductive grid 516 is not less than the height of the micro light-emitting diodes.

[0120] Refer to Figure 21In Figure b, a transparent conductive layer 521 is prepared above the light-emitting region. The projection of the transparent conductive layer 521 on the driving substrate covers the light-emitting region. The transparent conductive layer 521 is in contact with the second electrode of the micro light-emitting diode, or it can be considered that the part of the transparent conductive layer 521 in contact with the micro light-emitting diode constitutes the second electrode of the micro light-emitting diode. The transparent conductive layer 521 is also electrically connected to the conductive grid of the light-emitting region. In this way, the second electrode of the micro light-emitting diode can be electrically connected to the conductive grid and the common electrode through the transparent conductive layer.

[0121] Refer to Figure 21 In Figure c, a lens layer 522 can be formed on the transparent conductive layer 521. The lens layer 522 includes a plurality of lenses. The plurality of lenses correspond to the plurality of micro light-emitting diodes one by one. The lens axis can be on the same straight line as the axis of the micro light-emitting diode, or it can also present a certain angle.

[0122] Alternatively, it can also be combined with Figure 20 Figure a` in and Figure 21 Figure d in Figure 21 Figure d in shows a display module in which a dielectric filling layer is not provided between the height control layer 511 and the driving substrate.

[0123] From Figures 19 to 21 The process flow shown: The method provided by the embodiment of the present application first forms a plurality of micro light-emitting diodes on the driving substrate, and then sequentially forms a first dielectric filling layer 510, a height control layer 511, and a second dielectric filling layer 512. Utilizing the characteristics that the removal rates of the height control layer 511 and the dielectric filling layer are different, the surface of the wafer can stop at the surface of the height control layer 511, thereby precisely controlling the height of the micro light-emitting diodes. After controlling the height of the micro light-emitting diodes, a conductive grid 516 is formed by grooving. Finally, a transparent conductive layer 521 is formed on the light-emitting region. Setting the conductive grid 516 can, on the one hand, change the current path of the micro light-emitting diodes, so that the current originally flowing through the transparent conductive layer 521 to the common electrode 519 flows through the conductive grid 516 to the common electrode 519, which can reduce the resistance and avoid the influence of IR Drop on the display effect. On the other hand, the conductive grid 516 can be an opaque grid, and the micro light-emitting diodes can be arranged in the grid holes formed by the conductive grid 516. The conductive grid 516 can block the light emitted by different micro light-emitting diodes and avoid the light emitted by different micro light-emitting diodes from crosstalking.

[0124] An embodiment of the present application further provides an electronic device, which includes a housing and the display module provided in the foregoing examples, and the display module can be installed on the housing. For example, the electronic device can be a mobile phone, a personal computer (PC), a tablet (pad), a smart wearable product (such as a smart watch, a smart bracelet), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a vehicle-mounted terminal, a display, and other electronic devices mentioned in the foregoing examples.

[0125] In the description of this specification, specific features, structures, materials, or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0126] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A display module, characterized in that, the display module includes: a driving substrate including a plurality of first electrode contacts and second electrode contacts, the first electrode contacts and the second electrode contacts being used to form a driving circuit with micro light-emitting diodes; a plurality of micro light-emitting diodes, the micro light-emitting diodes including a first electrode and a second electrode, the plurality of micro light-emitting diodes corresponding to the plurality of first electrode contacts one by one, and the first electrode of the micro light-emitting diode being electrically connected to the first electrode contact; a conductive grid including a plurality of grids, the conductive grid being electrically connected to the second electrode contacts; a transparent conductive layer covering the plurality of micro light-emitting diodes and the conductive grid, the second electrode of the micro light-emitting diode being electrically connected to the conductive grid through the transparent conductive layer, and the resistivity of the material of the conductive grid being less than the resistivity of the material of the transparent conductive layer.

2. The display module according to claim 1, characterized in that, a common electrode is further provided on the driving substrate, and the conductive grid is electrically connected to the second electrode contacts through the common electrode.

3. The display module according to claim 1, characterized in that, the conductive grid is electrically connected to the second electrode contacts through the internal circuit of the driving substrate.

4. The display module according to any one of claims 1 to 3, characterized in that, a height control layer is further provided on the driving substrate, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer.

5. The display module according to claim 4, characterized in that, the display module further includes a dielectric filling layer, the dielectric filling layer being respectively provided between adjacent micro light-emitting diodes and between the height control layer and the driving substrate, and the materials of the height control layer, the dielectric filling layer, and the micro light-emitting diodes having different removal rates.

6. The display module according to any one of claims 1 to 5, characterized in that, a plurality of the micro light-emitting diodes are provided in the area defined by each grid.

7. The display module according to any one of claims 1 to 5, characterized in that, one micro light-emitting diode is provided in the area defined by each grid.

8. The display module according to any one of claims 1 to 7, characterized in that, the width of the grid lines of the conductive grid is 10 nm to 1000 nm.

9. The display module according to any one of claims 1 to 8, characterized in that, the conductive grid includes a lower surface facing the driving substrate and an upper surface facing away from the driving substrate in a direction perpendicular to the driving substrate, and the micro light-emitting diodes include a lower surface facing the driving substrate and an upper surface facing away from the driving substrate in a direction perpendicular to the driving substrate; the distance from the lower surface of the conductive grid to the driving substrate is less than or equal to the distance from the lower surface of the micro light-emitting diode to the driving substrate; The distance from the upper surface of the conductive grid to the driving substrate is greater than or equal to the distance from the upper surface of the micro light-emitting diode to the driving substrate.

10. The display module according to any one of claims 1 to 9, wherein, the height of the conductive grid in the direction perpendicular to the driving substrate is 1 to 2 times the height of the micro light-emitting diode in the direction perpendicular to the driving substrate.

11. The display module according to any one of claims 1 to 9, wherein, the display module further includes a lens layer, the lens layer is disposed on the transparent conductive layer, and the lens layer is used to collimate the light emitted by the micro light-emitting diode.

12. A method for manufacturing a display module, wherein, the method includes: forming a plurality of micro light-emitting diodes on a driving substrate, the micro light-emitting diodes include a first electrode and a second electrode disposed opposite to each other, the driving substrate includes a plurality of first electrode contacts and second electrode contacts, the plurality of micro light-emitting diodes correspond to the plurality of first electrode contacts one by one, and the first electrode of the micro light-emitting diode contacts the corresponding first electrode contact of the micro light-emitting diode; forming a common electrode and a conductive grid on the driving substrate, the common electrode is electrically connected to the second electrode contact, the conductive grid is electrically connected to the common electrode, the conductive grid includes a plurality of grids, the micro light-emitting diodes correspond to the grids, and the micro light-emitting diodes are located within the regions defined by their corresponding grids; forming a transparent conductive layer, the transparent conductive layer covers the plurality of micro light-emitting diodes and the conductive grid, and the second electrode of the micro light-emitting diode is electrically connected to the conductive grid through the transparent conductive layer.

13. The method according to claim 12, wherein, before forming the common electrode and the conductive grid on the driving substrate, the method further includes: forming a height control layer on the driving substrate, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer.

14. The method according to claim 13, wherein, forming the height control layer on the driving substrate, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, includes: forming a first dielectric filling layer on the wafer surface after forming the micro light-emitting diodes; forming the height control layer on the first dielectric filling layer; forming a second dielectric filling layer on the height control layer; performing a planarization process on the wafer after forming the second dielectric filling layer, so that the height of the wafer surface stops at the surface of the height control layer, and the upper surface of the micro light-emitting diode is flush with the upper surface of the height control layer, wherein the material of the height control layer has a different removal rate from the material of the micro light-emitting diode and the materials of the first dielectric filling layer and the second dielectric filling layer.

15. The method according to claim 13 or 14, wherein, forming the common electrode and the conductive grid on the driving substrate, and the conductive grid contacts the common electrode, includes: After forming the height control layer, a grid-shaped groove and a common electrode groove are formed on the surface of the chip, and the grid-shaped groove communicates with the common electrode groove; The conductive grid is formed in the grid-shaped groove, and the common electrode is formed in the common electrode groove.

16. An electronic device, characterized in that, it includes a housing and the display module according to any one of claims 1 to 11, and the display module is installed on the housing.

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