Light-emitting substrate and display device

Abstract

A light-emitting substrate and a display device. The light-emitting substrate comprises: a base substrate; a driving layer arranged on the base substrate, the driving layer comprising a plurality of conductive pads; and a plurality of light-emitting units located on the side of the driving layer away from the base substrate, wherein each light-emitting unit comprises a plurality of electrodes, each electrode is electrically connected to one conductive pad by means of a corresponding solder portion, and the solder portion comprises silver element; the orthographic projection of the electrode on the base substrate is located within the range of the orthographic projection of the solder portion on the substrate, or a part of the orthographic projection of the electrode on the base substrate is a first extended region; the electrode comprises a first metal layer located in the first extended region; the material of the first metal layer comprises silver; the first extended region is located outside the orthographic projection of the solder portion on the base substrate; the area S of the first extended region satisfies: [Equation 1]; the electrodes of the light-emitting unit comprise a first electrode and a second electrode, and L is the minimum distance between the first electrode and the second electrode.

Description

Light-emitting substrate and display device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, in particular to a light-emitting substrate and a display device. BACKGROUND

[0002] With the development of the display technical field, the mini Light-Emitting Diode (LED) display substrate has the advantages of high color purity, wide dynamic range, high brightness, high definition, low working voltage, small power consumption, long service life, impact resistance, large viewing angle and stable and reliable working, etc. The LED display substrate will become the most advantageous new generation of display media, wherein the LED light-emitting substrate includes a plurality of LED light-emitting chips arranged in an array. The research and development of the LED light-emitting chip, especially the mini-LED and micro-LED light-emitting chip, has become an important issue in the display field.

[0003] In the LED light-emitting substrate, the LED light-emitting chip is welded with the solder and the pad to realize conduction. However, the current LED light-emitting substrate is prone to the problem of short circuit between the cathode and the anode of the LED light-emitting chip. SUMMARY

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and proposes a light-emitting substrate and a display device.

[0005] The present disclosure provides a light-emitting substrate, comprising:

[0006] a substrate;

[0007] a driving layer disposed on the substrate, the driving layer having a plurality of conductive pads;

[0008] a plurality of light-emitting units located on the side of the driving layer away from the substrate, the light-emitting unit having a plurality of electrodes, each of the electrodes being electrically connected to one of the conductive pads through a corresponding solder part, the solder part including a silver element;

[0009] wherein the orthographic projection of the electrode on the substrate is located within the orthographic projection range of the solder part on the substrate, or

[0010] part of the orthographic projection of the electrode on the substrate is a first overhang region, the electrode includes a first metal layer located in the first overhang region, and the material of the first metal layer includes silver; the first overhang region is located outside the orthographic projection of the solder part on the substrate, and the area S of the first overhang region satisfies: wherein the electrode of the light-emitting unit includes a first electrode and a second electrode, and L is the minimum distance between the first electrode and the second electrode.

[0011] In some embodiments, L is in the range of 0.1-0.3 mm.

[0012] In some embodiments, a projection of the conductive pad on the substrate is within a projection range of the corresponding solder portion on the substrate, and a distance between a projection edge of the conductive pad and a projection edge of the solder portion is less than or equal to 0.16 mm.

[0013] In some embodiments, the electrode includes a first surface facing the substrate, a second surface facing away from the substrate, and a first side surface connecting the first surface and the second surface, at least a portion of the first side surface being in contact with the solder portion.

[0014] In some embodiments, the electrode includes a second metal layer, a material of the second metal layer including a second metal, the second metal including copper; a material of the solder portion including an alloy of silver, the second metal, and tin;

[0015] wherein the second metal layer is in direct contact with the solder portion, or

[0016] the electrode further includes a third metal layer between the second metal layer and the solder portion, a material of the third metal layer including silver.

[0017] In some embodiments, the electrode includes a first metal layer in the first overhanging region, and the electrode further includes a third metal layer;

[0018] the third metal layer is connected to the first metal layer as an integral structure.

[0019] In some embodiments, the first electrode includes a first main portion extending along a first direction, and a first protruding portion and a second protruding portion connected to a side of the first main portion facing the second electrode, the first protruding portion and the second protruding portion being arranged along a first direction; a size of the first protruding portion in a second direction is greater than a size of the second protruding portion in the second direction; the second direction is a direction from the first electrode to the second electrode, and the first direction is perpendicular to the second direction.

[0020] a projection of the second protruding portion on the substrate is within a projection range of the corresponding solder portion on the substrate.

[0021] In some embodiments, the plurality of conductive pads includes a first conductive pad electrically connected to the first electrode, and a second conductive pad electrically connected to the second electrode.

[0022] The first conductive pad comprises a second main body portion extending along the first direction and at least one third protruding portion connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps with a projection of the first main body portion on the substrate.

[0023] The projection of the first protruding portion on the substrate is located within a range of the projection of one of the third protruding portions on the substrate, or the projection of the first protruding portion on the substrate partially overlaps with the projection of one of the third protruding portions on the substrate.

[0024] In some embodiments, the plurality of conductive pads comprises a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode.

[0025] The first conductive pad comprises a second main body portion extending along the first direction and at least one third protruding portion connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps with a projection of the first main body portion on the substrate.

[0026] A part of the projection of the second protruding portion on the substrate is a second exceeding area, the second exceeding area is located outside the projection of the first conductive pad on the substrate, and a maximum distance between an edge of the second exceeding area and an edge of the projection of the first conductive pad is not more than 0.16 mm.

[0027] In some embodiments, the plurality of conductive pads comprises a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode.

[0028] The first conductive pad comprises a second main body portion extending along the first direction and two third protruding portions connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps with a projection of the first main body portion on the substrate.

[0029] The projection of the second protruding portion on the substrate is located within a range of the projection of one of the third protruding portions on the substrate, and the projection of the first protruding portion on the substrate overlaps with the projection of another one of the third protruding portions on the substrate.

[0030] In some embodiments, the plurality of conductive pads comprises a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode.

[0031] The first conductive pad includes a second main body portion extending along the first direction and at least one third protruding portion connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps a projection of the first main body portion on the substrate;

[0032] At least one of the first protruding portion and the second protruding portion has a projection on the substrate that overlaps a projection of the third protruding portion on the substrate;

[0033] The first protruding portion has a first inner edge facing the second main body portion, and the first inner edge extends along a third direction;

[0034] The second conductive pad includes a first edge facing the second main body portion and a second edge connected to the first edge, the first edge extends along the first direction, and the second edge is disposed opposite the third protruding portion; the third protruding portion has a second inner edge facing the second edge, and the second inner edge and the second edge both extend along the third direction, the third direction intersects the first direction and the second direction.

[0035] In some embodiments, the second electrode has a third edge facing the first main body portion and a fourth edge connected to the third edge, the third edge includes a straight portion and a first recessed portion, the straight portion is in the same direction as the first main body portion, and the first recessed portion is disposed opposite the second protruding portion and curved away from the second protruding portion;

[0036] The first protruding portion has a first inner edge facing the second protruding portion; the fourth edge is disposed opposite the first protruding portion, and the fourth edge and the first inner edge both extend along a third direction, the third direction intersects the direction of the first main body portion and the second direction.

[0037] In some embodiments, the plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode;

[0038] The first conductive pad includes a second main body portion and a third protruding portion connected to a side of the second main body portion facing the second conductive pad, and the light emitting unit includes a plurality of the first electrodes arranged on the same side of the second electrode along a first direction, and the first conductive pad is electrically connected to the first electrode one by one;

[0039] The first electrode has a projection on the substrate within the projection range of the first conductive pad on the substrate, or the projection of the first electrode on the substrate covers and exceeds the projection of the first conductive pad on the substrate, and the distance between the projection edge of the first electrode and the projection edge of the first conductive pad is less than or equal to 0.16 mm.

[0040] In some embodiments, the second conductive pad has a second recess corresponding to the third protrusion towards the edge of the first conductive pad, and the second recess is oppositely arranged with the corresponding third protrusion in a second direction, which is the direction from the first electrode to the second electrode.

[0041] In some embodiments, the light-emitting unit is electrically connected to two first conductive pads, and each of the two third protrusions towards the edge of the other third protrusion is arc-shaped, and the distance between the opposite edges of the two third protrusions gradually increases in the direction from the first conductive pad to the second conductive pad.

[0042] In some embodiments, the plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode, and the minimum distance between the first conductive pad and the second conductive pad is in the range of 0.1-0.3 mm.

[0043] The present disclosure also provides a display device comprising the light-emitting substrate described above. BRIEF DESCRIPTION OF DRAWINGS

[0044] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the specific embodiments described below to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0045] FIG. 1 is a schematic diagram of a light-emitting substrate provided in some embodiments.

[0046] FIG. 2A is a plan view of a conductive pad provided in some embodiments.

[0047] FIG. 2B is a plan view of a light-emitting unit provided in some embodiments.

[0048] FIG. 3 is a schematic diagram of the conductive pad in FIG. 2A and the electrode of the light-emitting unit in FIG. 2B superimposed.

[0049] FIG. 4A is a cross-sectional view of an electrode provided in some embodiments.

[0050] FIG. 4B is a cross-sectional view of a light-emitting unit connected to a conductive pad provided in some embodiments.

[0051] FIG. 5 is a schematic diagram of a light-emitting substrate provided in some embodiments of the present disclosure.

[0052] FIG. 6A is two cross-sectional diagrams of the electrical connection between a light-emitting unit and a conductive pad provided in some embodiments of the present disclosure.

[0053] FIG. 6B is two cross-sectional diagrams of the electrical connection between a light-emitting unit and a conductive pad provided in some other embodiments of the present disclosure.

[0054] FIG. 7A is a plan view of a light-emitting unit, a conductive pad, a solder portion, and a plan view of the superposition of the conductive pad and the solder portion provided in some embodiments of the present disclosure.

[0055] FIG. 7B is a plan view of the superposition of the light-emitting unit, the solder portion, and the conductive pad in FIG. 7A.

[0056] FIG. 8A is a plan view of a light-emitting unit, a conductive pad, a solder portion, and a plan view of the superposition of the conductive pad and the solder portion provided in some other embodiments of the present disclosure.

[0057] FIG. 8B is a plan view of the superposition of the light-emitting unit, the solder portion, and the conductive pad in FIG. 8A.

[0058] FIG. 9A is a plan view of a light-emitting unit, a conductive pad, a solder portion, and a plan view of the superposition of the conductive pad and the solder portion provided in some further embodiments of the present disclosure.

[0059] FIG. 9B is a plan view of the superposition of the light-emitting unit, the solder portion, and the conductive pad in FIG. 9A.

[0060] FIG. 10A is a plan view of a light-emitting unit and a conductive pad provided in some yet further embodiments of the present disclosure.

[0061] FIG. 10B is a plan view of the superposition of the light-emitting unit and the conductive pad in FIG. 10A.

[0062] FIG. 11 is a schematic diagram of a display device provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0063] The specific embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0064] To make the objects, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort belong within the scope of the present disclosure.

[0065] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood as the common meanings of the terms to those skilled in the art with ordinary skill. The terms "first", "second", and similar terms in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different components. Similarly, the terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0066] As used herein, "parallel", "perpendicular" include the recited condition and conditions similar to the recited condition within an acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art considering the measurement being discussed and the error associated with a particular measurement (i.e., limitations of the measurement system). For example, "parallel" includes absolute parallel and near-parallel, wherein the acceptable deviation range for near-parallel can be, for example, within 5°; "perpendicular" includes absolute perpendicular and near-perpendicular, wherein the acceptable deviation range for near-perpendicular can also be, for example, within 5°.

[0067] It should be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers can also be present.

[0068] Exemplary embodiments are described herein with reference to cross-sectional and / or plan view illustrations that are idealized examples. In the interest of clarity, not all of the layer and regions are shown in the drawings with the same dimensions. For example, the thickness of layers and regions can be exaggerated in the drawings. Thus, the exemplary embodiments should not be construed as limited to the shapes of regions illustrated in the drawings, which are schematic, but include shapes that result from, for example, manufacturing. The regions illustrated in the drawings are schematic and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the exemplary embodiments in terms of the scope.

[0069] FIG. 1 is a schematic diagram of a light-emitting substrate provided in some embodiments, which can be optionally used in a backlight module. As shown in FIG. 1, the light-emitting substrate includes a driving layer 20 disposed on one side of a substrate 10 and a plurality of light-emitting units 30 located on a side of the driving layer 20 away from the substrate 10, the driving layer 20 includes a plurality of conductive pads 21, the plurality of conductive pads 21 include a plurality of first conductive pads 211 and a plurality of second conductive pads 212. The light-emitting units 30 are, for example, Mini-LED light-emitting chips or Micro-LED light-emitting chips. The light-emitting units 30 have a plurality of electrodes 31, for example, the plurality of electrodes 31 include a first electrode 311 and a second electrode 312, one of the first electrode 311 and the second electrode 312 is an anode, and the other is a cathode. Each electrode 31 of the light-emitting unit 30 corresponds to a solder part 40, and each electrode 31 is electrically connected to one conductive pad 21 through a corresponding solder part 40. Specifically, the first electrode 311 is electrically connected to the first conductive pad 211 through the solder part 40, and the second electrode 312 is electrically connected to the second conductive pad 212 through the solder part 40.

[0070] For example, the light-emitting substrate can further include a reflective layer 50 having a plurality of light transmission holes, the solder part 40 electrically connects the electrode 31 and the conductive pad 21 through the light transmission hole, and the reflective layer 50 can reflect the light of the light-emitting unit 30 to improve the light efficiency. For example, the light-emitting substrate can further include a support 70 for supporting a diffusion sheet in the backlight module to provide a certain light mixing distance. For example, the light-emitting substrate further includes a circuit layer and a component 60 electrically connected to the circuit layer, the component 60 can be a driving chip, a capacitor, a resistor, a connector, etc.

[0071] Figure 2A is a plan view of the conductive pad 21 provided in some embodiments, Figure 2B is a plan view of the light emitting unit 30 provided in some embodiments, Figure 3 is a schematic view of the conductive pad 21 in Figure 2A and the electrode 31 of the light emitting unit 30 in Figure 2B superimposed, Figure 4A is a sectional view of the electrode provided in some embodiments, and Figure 4B is a sectional view of the light emitting unit 30 connected with the conductive pad 21 provided in some embodiments. As shown in Figures 2A to 4B, the light emitting unit 30 includes a light emitting portion 32, a first electrode 311 and a second electrode 312 electrically connected to the same side of the light emitting portion 32, for example, the light emitting portion 32 is located on the side of the support layer 72 away from the substrate 10, the first electrode 311 and the second electrode 312 are located on the side of the support layer 72 close to the substrate 10, and the light emitting portion 32 is connected with the first electrode 311 and the second electrode 312 respectively through the connecting line 71. As shown in Figure 4A, each electrode 31 includes an initial metal layer 31d and a second metal layer 31b located between the initial metal layer 31a and the light emitting portion 32. Generally, the initial metal layer 31a is a silver metal layer, so that the electrode 31 can be soldered with the solder portion 40 to form an alloy compound. And silver has good thermal conductivity, electrical conductivity, solderability and polishing at room temperature. The thickness of the initial metal layer 31a is between 0.1 microns and 5 microns. Among them, at least part of the initial metal layer 31a reacts with the solder after the electrode 31 is soldered with the solder to form an alloy.

[0072] It should be noted that the "solder" in the present disclosure refers to the material before being soldered with the electrode 31, for example, tin paste; and the "solder portion 40" refers to the alloy structure formed after being soldered with the electrode 31.

[0073] In some embodiments, the first electrode 311 includes a first body portion 3110, and a first protruding portion 3111 and a second protruding portion 3112 electrically connected to the first body portion 3110, the first protruding portion 3111 and the second protruding portion 3112 are located on the side of the first body portion 3110 close to the second electrode 312, and the first protruding portion 3111 and the second protruding portion 3112 are arranged along a first direction. The size of the first protruding portion 3111 in a second direction is greater than the size of the second protruding portion 3112 in the second direction, wherein the second direction is the direction from the first electrode 311 to the second electrode 312, and the first direction is perpendicular to the second direction.

[0074] For example, the first protruding portion 3111 and the second protruding portion 3112 each protrude beyond the pad in the second direction, in which case, when reflow soldering is performed, part of the first electrode 311 is not covered by the solder, resulting in direct exposure of silver metal in the electrode 31. For example, in one example, the first protruding portion 3111 and the second protruding portion 3112 each protrude beyond the pad by 0.16 mm and 0.4 mm in the second direction. When reflow soldering is performed, solder (e.g., solder paste) is disposed on the conductive pad 21, and the solder is soldered to the electrode 31. During reflow soldering, the solder paste climbs along the part of the first electrode 311 that protrudes beyond the first conductive pad 211, hereinafter referred to as "solder climbing", and the range covered by the solder portion 40 on the electrode 31 after soldering is larger than the range covered before soldering. In this case, the first protruding portion 3111 is still not covered by the solder portion 40 after soldering in the second direction by a range of 0.24 mm, resulting in exposure of silver.

[0075] If a large area of silver is exposed, then in a reliability test in a water vapor environment, under the condition of power on, the exposed silver metal is ionized into silver ions, which migrate from the first electrode 311 to the second electrode 312 along the shortest path under the action of water vapor and pressure difference, and are reduced to silver metal at the second electrode 312, resulting in short circuit between the first electrode 311 and the second electrode 312, and further causing abnormal light emission of the light-emitting substrate.

[0076] To solve the above technical problems, the present disclosure provides a light-emitting substrate, FIG. 5 is a schematic diagram of a light-emitting substrate provided in some embodiments of the present disclosure, FIG. 6A is two cross-sectional diagrams of the electrical connection between a light-emitting unit 30 and a conductive pad 21 provided in some embodiments of the present disclosure, FIG. 6B is two cross-sectional diagrams of the electrical connection between a light-emitting unit 30 and a conductive pad 21 provided in some other embodiments of the present disclosure, FIG. 7A is a plan view of a light-emitting unit 30, a conductive pad 21, and a solder part 40, and a plan view of the superposition of the conductive pad 21 and the solder part 40, as shown in (a) to (d) in FIG. 7A, FIG. 7B is a plan view of the superposition of the light-emitting unit 30, the solder part 40, and the conductive pad 21 in FIG. 7A, FIG. 8A is a plan view of a light-emitting unit 30, a conductive pad 21, and a solder part 40, and a plan view of the superposition of the conductive pad 21 and the solder part 40, as shown in (a) to (d) in FIG. 8A, FIG. 8B is a plan view of the superposition of the light-emitting unit 30, the solder part 40, and the conductive pad 21 in FIG. 8A, FIG. 9A is a plan view of a light-emitting unit 30, a conductive pad 21, and a solder part 40, and a plan view of the superposition of the conductive pad 21 and the solder part 40, as shown in (a) to (d) in FIG. 9A, and FIG. 9B is a plan view of the superposition of the light-emitting unit 30, the solder part 40, and the conductive pad 21 in FIG. 9A.

[0077] As shown in FIG. 5, the light-emitting substrate includes a substrate 10, a driving layer 20, and a plurality of light-emitting units 30 disposed on the substrate 10. The driving layer 20 has a plurality of conductive pads 21, and the light-emitting unit 30 is located on the side of the driving layer 20 away from the substrate 10. The light-emitting unit 30 has a plurality of electrodes 31, for example, the plurality of electrodes 31 includes a first electrode 311 and a second electrode 312. Each electrode 31 is electrically connected to a conductive pad 21 through a corresponding solder part 40. For example, the plurality of conductive pads 21 includes a first conductive pad 211 electrically connected to the first electrode 311 and a second conductive pad 212 electrically connected to the second electrode 312. The first electrode 311 is electrically connected to the first conductive pad 211 through a corresponding solder part 40, and the second electrode 312 is electrically connected to the second conductive pad 212 through a corresponding solder part 40.

[0078] In some examples, the solder part 40 includes silver elements. For example, the silver elements in the solder part 40 can be enriched on the side of the solder part 40 close to the electrode 31. For example, before the light-emitting unit 30 is soldered with the solder, the structure of the electrode 31 is as shown in FIG. 4A. When the electrode 31 is soldered with the solder, the silver in the electrode 31 forms an alloy with the solder to form the solder part 40. For example, the silver elements are enriched on the side of the solder part 40 close to the electrode 31.

[0079] For example, the solder part 40 includes silver elements, and the solder part 40 itself includes elements before welding (i.e., solder); for another example, the solder part 40 can also include elements (e.g., copper elements) of the conductive pad 21.

[0080] For example, the material of the solder part 40 includes an alloy of silver and tin, and for another example, the material of the solder part 40 includes an alloy of copper, tin and silver.

[0081] For example, the material of the solder part 40 is silver-tin alloy, and for another example, the material of the solder part 40 is tin-silver-copper alloy.

[0082] As shown in FIG. 6A, a first projection relationship between the electrode 31 and the solder part 40 is that the orthographic projection of the electrode 31 on the substrate 10 is located within the orthographic projection range of the solder part 40 on the substrate 10. Alternatively, as shown in FIG. 6B, a second projection relationship between the electrode 31 and the solder part 40 is that a part of the orthographic projection of the electrode 31 on the substrate 10 is a first overhang area A1, the electrode 31 includes a first metal layer 31a located in the first overhang area A1, the material of the first metal layer 31a includes silver, for example, the material of the first metal layer 31a is silver. The first overhang area A1 is located outside the orthographic projection of the solder part 40 on the substrate 10, and the area S of the first overhang area A1 satisfies: wherein L is the minimum distance between the first electrode 311 and the second electrode 312.

[0083] It should be noted that in FIG. 6B, the second projection relationship is described only by taking the first electrode 311 as an example. In the embodiments of the present disclosure, the first electrode 311 and the second electrode 312 can simultaneously satisfy the above first projection relationship, or simultaneously satisfy the above second projection relationship; or one of the first electrode 311 and the second electrode 312 satisfies the above first projection relationship, and the other satisfies the second projection relationship.

[0084] It should be further noted that before welding, the film layer structure of the electrode 31 can be as shown in FIG. 4A, including an initial metal layer 31d and a second metal layer 31b; after the electrode 31 is welded with the solder, the area where the initial metal layer 31d contacts the solder can be completely reacted with the solder to form an alloy, or can be partially reacted with the solder to form an alloy. If the area where the initial metal layer 31d contacts the solder does not completely form an alloy, then a certain thickness of the metal layer is still retained. If a part of the initial metal layer 31d does not contact the solder, then the material of this part remains unchanged. That is, in the present disclosure, for the above first projection relationship, a part of the initial metal layer 31d can be retained in the electrode 31, or can not be retained (i.e., the electrode 31 can include a silver metal layer close to the solder part 40, or can not include a silver metal layer); for the above second projection relationship, the first metal layer 31a is a part of the initial metal layer 31d that does not contact the solder.

[0085] It should be understood that the first overreaching area A1 is a part of the area of the normal projection of the electrode 31 on the substrate 10 before welding, and does not include the migration area generated when silver migration occurs.

[0086] In the embodiments of the present disclosure, the normal projection of the electrode 31 on the substrate 10 is located within the range of the normal projection of the solder part 40 on the substrate 10, so that the solder part 40 can cover the electrode 31, and the problem of short circuit between the first electrode 311 and the second electrode 312 caused by silver ion migration in the reliability test can be reduced or prevented. Alternatively, a part of the normal projection of the electrode 31 on the substrate 10 is the first overreaching area A1, the first overreaching area A1 is located outside the normal projection of the solder part 40 on the substrate 10, and the area S of the first overreaching area A1 satisfies: In this case, the area of the electrode 31 not covered by the solder part 40 is small, and when the reliability test is performed, silver ions are not sufficient to migrate to the other electrode 31 through a long distance, thereby reducing or preventing the problem of short circuit between the first electrode 311 and the second electrode 312.

[0087] In some embodiments, the minimum distance L between the first electrode 311 and the second electrode 312 is greater than or equal to 0.1 mm, so as to ensure that there is a certain safety distance between the first electrode 311 and the second electrode 312, and reduce the occurrence of short circuit between the first electrode 311 and the second electrode 312. Further, L is in the range of 0.1 mm to 0.3 mm, so as to prevent the light emitting unit 30 from occupying a large area while ensuring that there is a certain safety distance between the first electrode 311 and the second electrode 312.

[0088] In some embodiments, the minimum distance between the first conductive pad 211 and the second conductive pad 212 connected to the same light emitting unit 30 is at least 0.1 mm, so as to ensure that there is a certain safety distance between the first conductive pad 211 and the second conductive pad 212, and reduce or prevent the occurrence of short circuit between the first conductive pad 211 and the second conductive pad 212. Further, the minimum distance between the first conductive pad 211 and the second conductive pad 212 connected to the same light emitting unit 30 is in the range of 0.1 mm to 0.3 mm, so as to prevent the light emitting unit 30 from occupying a large area while reducing or preventing the occurrence of short circuit between the first conductive pad 211 and the second conductive pad 212.

[0089] In some embodiments, as shown in FIG. 6, the electrode 31 includes a first surface facing the substrate 10, a second surface facing away from the substrate 10, and a first side surface connecting the first surface and the second surface, at least a part of the first side surface being in contact with the solder part 40, so as to further reduce the exposed area of the silver metal layer.

[0090] In some embodiments, as shown in FIGS. 6A and 6B, the electrode 31 includes a second metal layer 31b, and a material of the second metal layer 31b includes a second metal, and the second metal includes copper, for example, the second metal is copper. A material of the solder portion 40 includes an alloy of silver, the second metal, and tin. For example, the material of the solder portion 40 is an alloy of silver, the second metal, and tin.

[0091] In some embodiments, as shown in FIG. 6A, a normal projection of the electrode 31 on the substrate 10 is located within a range of a normal projection of the corresponding solder portion 40 on the substrate 10, and the second metal layer 31b of the electrode 31 can be in direct contact with the solder portion 40. That is, in the soldering process of the electrode 31 and the solder, the entire initial metal layer reacts with the solder, and the solder portion 40 is formed by the alloy material.

[0092] In some embodiments, as shown in FIG. 6A, a normal projection of the electrode 31 on the substrate 10 is located within a range of a normal projection of the corresponding solder portion 40 on the substrate 10, and the second metal layer 31b of the electrode 31 can be in direct contact with the solder portion 40. That is, in the soldering process of the electrode 31 and the solder, the entire initial metal layer reacts with the solder, and the solder portion 40 is formed by the alloy material.

[0093] In some embodiments, as shown in FIG. 6A, a normal projection of the electrode 31 on the substrate 10 is located within a range of a normal projection of the corresponding solder portion 40 on the substrate 10, and the second metal layer 31b of the electrode 31 can be in direct contact with the solder portion 40. That is, in the soldering process of the electrode 31 and the solder, the entire initial metal layer reacts with the solder, and the solder portion 40 is formed by the alloy material.

[0094] In yet some examples, as shown in (b) of FIG. 6B, the orthogonal projection of the electrode 31 on the substrate 10 includes the above-mentioned first overhang region A1, and the electrode 31 can further include a second metal layer 31b and a third metal layer 31c between the second metal layer 31b and the solder part 40, the material of the third metal layer 31c includes silver, for example, the third metal layer 31c is a silver metal layer. The third metal layer 31c is connected to the first metal layer 31a as an integral structure, that is, in the process of welding the electrode 31 and the solder, in the region of the initial metal layer that is in contact with the solder, part of the initial metal layer reacts with the solder to form the solder part 40 of the alloy material, and the other part does not react to form the third metal layer 31c; the region of the initial metal layer that is not in contact with the solder (i.e., the first overhang region A1) does not participate in the reaction to form the first metal layer 31a. The thickness of the third metal layer 31c is less than the thickness of the initial metal layer 31a.

[0095] In some embodiments, the orthogonal projection of the conductive pad 21 on the substrate 10 is located within the range of the orthogonal projection of the corresponding solder part 40 on the substrate 10, and the distance between the edge of the orthogonal projection of the conductive pad 21 and the edge of the orthogonal projection of the solder part 40 is less than or equal to 0.16 mm. Specifically, when the orthogonal projection of the electrode 31 on the substrate 10 is located within the range of the orthogonal projection of the conductive pad 21 on the substrate 10, the orthogonal projection of the conductive pad 21 on the substrate 10 is located within the range of the orthogonal projection of the solder part 40 on the substrate 10, so that the solder part 40 can sufficiently cover the electrode 31; when a part of the orthogonal projection of the electrode 31 on the substrate 10 is outside the conductive pad 21, during the reflow soldering process, the solder creeps along the electrode 31, and the creep distance is less than or equal to 0.16 mm, that is, there is a distance of no more than 0.16 mm between the edge of the orthogonal projection of the solder part 40 and the edge of the orthogonal projection of the conductive pad 21.

[0096] In some embodiments, the orthogonal projection of the electrode 31 on the substrate 10 is located within the range of the orthogonal projection of the solder part 40 on the substrate 10, and the edge of the orthogonal projection of the electrode 31 is inwardly retracted by 0.16 mm to obtain a first region, in one example, the orthogonal projection of the conductive pad 21 on the substrate 10 covers at least the first region, and in addition, a certain safety distance, for example, at least 0.1 mm, should be left between the conductive pads 21 connected by the first electrode 31 and the second electrode 32 of the same light emitting unit. In this case, after the conductive pad 21 is fully coated with solder and undergoes reflow soldering, the orthogonal projection of the solder part 40 on the substrate 10 can cover the orthogonal projection of the electrode 31 on the substrate 10.

[0097] In some embodiments, as shown in FIGS. 7A-9B, the orthographic projection of the second electrode 312 on the substrate 10 is within the orthographic projection of the second conductive pad 212 on the substrate 10, so that the solder part 40 formed on the second conductive pad 212 can sufficiently cover the surface of the second electrode 312 facing the substrate 10. In other embodiments, a part of the orthographic projection of the second electrode 312 on the substrate 10 can be outside the orthographic projection of the second conductive pad 212 on the substrate 10, and the distance of the overhang is less than or equal to 0.16 mm. In this case, during the reflow soldering process, the solder climbs along the second electrode 312, and the finally formed solder part 40 can also cover the surface of the second electrode 312 facing the substrate 10, that is, the orthographic projection of the second electrode 312 on the substrate 10 is within the orthographic projection of the solder part 40 on the substrate 10.

[0098] In the embodiments of the present disclosure, the orthographic projection of the first electrode 311 on the substrate 10 can be within the orthographic projection of the first conductive pad 211 on the substrate 10, or a part of the orthographic projection of the first electrode 311 on the substrate 10 can be outside the orthographic projection of the first conductive pad 211 on the substrate 10. The following will be described in conjunction with specific drawings.

[0099] In some embodiments, as shown in FIGS. 7A-9B, the first electrode 311 includes a first main body part 3110 extending along a first direction, and a first protruding part 3111 and a second protruding part 3112 connected to the side of the first main body part 3110 facing the second electrode 312, and the first protruding part 3111 and the second protruding part 3112 are arranged along the first direction; the size of the first protruding part 3111 in the first direction is greater than the size of the second protruding part 3112 in the second direction; the second direction is the direction from the first electrode 311 to the second electrode 312, and the first direction is perpendicular to the second direction. The orthographic projection of the second protruding part 3112 on the substrate 10 is within the orthographic projection of the corresponding solder part 40 on the substrate 10, so that the second protruding part 3112 can be covered by the solder part 40, reducing or preventing the problem of short circuit between the first electrode 311 and the second electrode 312 caused by silver exposure.

[0100] As shown in FIGS. 7A-9B, in some embodiments, the first conductive pad 211 includes a second main portion 2110 extending in the first direction and at least one third protruding portion 2111 connected to a side of the second main portion 2110 facing the second conductive pad 212, and a projection of the second main portion 2110 on the substrate 10 overlaps with a projection of the first main portion 3110 on the substrate 10, for example, the projection of the first main portion 3110 on the substrate 10 is within the projection of the second main portion on the substrate 10, so that after the reflow soldering process by applying solder on the first conductive pad 211, a projection of the solder portion 40 on the substrate 10 can completely cover the projection of the first main portion 3110 on the substrate 10. For another example, a part of the projection of the first main portion 3110 on the substrate 10 exceeds the projection of the second main portion 2110 on the substrate 10, and a distance between an edge of the exceeding part and an edge of the projection of the second main portion 2110 is not more than 0.16 mm, so that when the reflow soldering process is performed by applying solder on the first conductive pad 211, the solder tin-creeps on the first main portion 3110, and a projection of the solder portion 40 on the substrate 10 can completely cover the projection of the first main portion 3110 on the substrate 10.

[0101] In some embodiments, at least one of the first protruding portion 3111 and the second protruding portion 3112 has a projection on the substrate 10 that overlaps with a projection of the third protruding portion 2111 on the substrate 10.

[0102] In some embodiments, as shown in FIGS. 7A and 7B, the projection of the first protruding portion 3111 on the substrate 10 is within the projection of one of the third protruding portions 2111 on the substrate 10, so that the solder portion 40 on the third protruding portion 2111 can cover the first protruding portion 3111, thereby reducing or preventing the occurrence of silver exposure on the first protruding portion 3111.

[0103] In addition, as shown in FIGS. 7A and 7B, a part of the projection of the second protruding portion 3112 on the substrate 10 is a second exceeding area A2, the second exceeding area A2 is outside the projection of the first conductive pad 211 on the substrate 10, and a maximum distance between an edge of the second exceeding area A2 and an edge of the projection of the first conductive pad 211 is not more than 0.16 mm, in this case, when reflow soldering is performed, the solder tin-creeps along the second protruding portion 3112, and a projection of the solder portion 40 on the substrate 10 can cover the projection of the second protruding portion 3112 on the substrate 10.

[0104] For the embodiments shown in FIGS. 7A and 7B, after the solder portions 40 are formed between the first conductive pad 211 and the first electrode 311, and between the second conductive pad 212 and the second electrode 312, the orthographic projections of the first electrode 311 and the second electrode 312 on the substrate 10 are respectively within the orthographic projection ranges of the corresponding solder portions 40 on the substrate 10.

[0105] For example, as shown in FIGS. 7A and 7B, the orthographic projection of the light emitting unit 30 on the substrate 10 is a square of 1.5 mm*1.5 mm, the left and right edges of the square are arranged along the first direction, the upper and lower edges of the square are arranged along the second direction, the distance from the left and right edges of the square to the second main body portion 2110 is 0.1 mm, the distance from the upper edge of the square to the second conductive pad 212 is 0.1 mm, and the distance from the lower edge of the square to the second conductive pad 212 is 0.1 mm. The width of the first main body portion 3110 is 0.15 mm, the dimension of the first protruding portion 3111 in the second direction is 0.5 mm, and the dimension of the second protruding portion 3112 in the second direction is 0.26 mm. The first conductive pad 211 includes the second main body portion 2110 and a third protruding portion 2111; the width of the second main body portion 2110 is 0.25 mm, a part of the orthographic projection of the second main body portion 2110 on the substrate 10 (with a width of 0.1 mm) is located on the side of the orthographic projection of the first main body portion 3110 close to the second conductive pad 212, the length of the third protruding portion 2111 in the second direction is 0.4 mm, and the orthographic projection of the third protruding portion 2111 on the substrate 10 covers the orthographic projection of the first protruding portion 3111 on the substrate 10. The dimension of the second overhang region in the second direction is 0.16 mm, the distance between the second protruding portion 3112 and the edge of the second conductive pad 212 facing the second main body portion 2110 in the second direction is 0.14 mm, and the distance between the two edges of the second main body portion 2110 and the second conductive pad 212 arranged oppositely in the second direction is 0.3 mm; the closest distance from the edge of the second conductive pad 212 away from the second main body portion 2110 and extending in the first direction to the second edge E2 is 0.3 mm.

[0106] In other embodiments, as shown in FIGS. 8A and 8B, the orthographic projection of the first protruding portion 3111 on the substrate 10 partially overlaps the orthographic projection of one of the third protruding portions 2111 on the substrate 10. Compared with FIG. 3, the structure of FIGS. 8A and 8B can reduce the silver exposed area of the first protruding portion 3111.

[0107] A part of the area of the orthographic projection of the first protruding portion 3111 on the substrate 10 is outside the orthographic projection of the third protruding portion 2111 on the substrate 10, and this part is referred to as a third exceeding area. In one example, the solder portion 40 connected to the first protruding portion 3111 exceeds the edge of the third protruding portion 2111 by 0.16 mm, and covers the entire third exceeding area; in another example, the solder portion 40 connected to the first protruding portion 3111 exceeds the edge of the third protruding portion 2111 by 0.16 mm, and a part of the third exceeding area is outside the orthographic projection of the solder portion 40, and this part is the first exceeding area A1 described above, and the area S of the first exceeding area A1 satisfies:

[0108] In addition, as shown in FIG. 8A, a part of the orthographic projection of the second protruding portion 3112 on the substrate 10 is a second exceeding area A2, the second exceeding area A2 is outside the orthographic projection of the first conductive pad 211 on the substrate 10, and the maximum distance between the edge of the second exceeding area A2 and the edge of the orthographic projection of the first conductive pad 211 is not more than 0.16 mm, in this case, during reflow soldering, solder climbs along the second protruding portion 3112, and the orthographic projection of the solder portion 40 on the substrate 10 can cover the orthographic projection of the second protruding portion 3112 on the substrate 10.

[0109] Exemplarily, in FIG. 8A, the orthogonal projection of the light emitting unit 30 on the substrate 10 is a square with a side length of 1.5 mm*1.5 mm, the left and right edges of the square are arranged along the first direction, the upper and lower edges of the square are arranged along the second direction, the distance from the left and right edges of the square to the second main body part 2110 is 0.1 mm, the distance from the upper edge of the square to the second conductive pad 212 is 0.1 mm, and the distance from the lower edge of the square to the second conductive pad 212 is 0.1 mm. The width of the first main body part 3110 is 0.15 mm, the size of the first protruding part 3111 in the second direction is 0.5 mm, and the size of the second protruding part 3112 in the second direction is 0.26 mm. The first conductive pad 211 includes the second main body part 2110 and a third protruding part 2111; the width of the second main body part 2110 is 0.25 mm, and a part of the orthogonal projection of the second main body part 2110 on the substrate 10 (with a width of 0.1 mm) is located on the side of the orthogonal projection of the first main body part 3110 close to the second conductive pad 212, and the length of the third protruding part 2111 in the second direction is 0.19 mm. The size of the second overhanging area in the second direction is 0.16 mm, the distance between the second protruding part 3112 and the edge of the second conductive pad 212 facing the second main body part 2110 in the second direction is 0.14 mm, and the distance between the two edges of the second main body part 2110 and the second conductive pad 212 arranged oppositely in the second direction is 0.3 mm. For the scheme in FIG. 8A, when the solder is arranged on the first conductive pad 211 and reflowed, the solder climbs along the first protruding part 3111, and in the case that the climbing length of the solder is 0.16 mm, the length of the solder part 40 on the third protruding part 2111 in the second direction is 0.19+0.16=0.35 mm, and the length of the part of the first protruding part 3111 not covered by the solder part 40 in the second direction (i.e., the size of the first overhanging area A1 in the second direction) is 0.05 mm.

[0110] In still some embodiments, as shown in FIG. 9A and FIG. 9B, the first conductive pad 211 includes two third protruding parts 2111, and the two protruding parts are arranged along the first direction on the side of the second main body part 2110 close to the second conductive pad 212. Among them, the orthogonal projection of the second protruding part 3112 on the substrate 10 is located within the orthogonal projection of one of the third protruding parts 2111 on the substrate 10, and the orthogonal projection of the first protruding part 3111 on the substrate 10 overlaps with the orthogonal projection of the other third protruding part 2111 on the substrate 10.

[0111] By locating the orthographic projection of the second protruding portion 3112 within the orthographic projection range of the third protruding portion 2111, it can be further ensured that the solder portion 40 located on the third protruding portion 2111 can cover the second protruding portion 3112, further preventing silver blowout from occurring on the second protruding portion 3112. The orthographic projection relationship between the first protruding portion 3111 and the third protruding portion 2111 can be the same as that in FIG. 7B, the orthographic projection of the first protruding portion 3111 on the substrate 10 is located within the orthographic projection range of one third protruding portion 2111 on the substrate 10, or the orthographic projection relationship between the first protruding portion 3111 and the third protruding portion 2111 is the same as that in FIG. 8B, the orthographic projection of the first protruding portion 3111 on the substrate 10 partially overlaps with the orthographic projection of the third protruding portion 2111 on the substrate 10.

[0112] In some embodiments, as shown in FIGS. 7A-9B, the first protruding portion 3111 has a first inner edge E01 connected with the first body portion 3110 and facing the second protruding portion 3112, and the first inner edge E01 extends along a third direction. The third direction intersects the first direction and intersects the second direction. The second electrode 312 has a third edge E3 facing the first body portion 3110 and a fourth edge E4 connected with the third edge E3, and the third edge E3 includes a straight portion and a first recessed portion, the straight portion is the same as the extension direction of the first body portion 3110, and the first recessed portion is oppositely arranged with the second protruding portion 3112 and curved away from the second protruding portion 3112. By arranging the first recessed portion, an avoidance space for avoiding the second protruding portion 3112 can be provided, so that the second protruding portion 3112 has sufficient spacing with the second electrode 312, thereby preventing the first electrode 311 from short-circuiting with the second electrode 312.

[0113] In addition, the fourth edge E4 is oppositely arranged with the first protruding portion 3111, and the fourth edge E4 and the first inner edge E01 of the first protruding portion 3111 both extend along the third direction, the third direction intersects the extension direction of the first body portion 3110 and intersects the second direction.

[0114] In the manufacturing process of the light-emitting substrate, the light-emitting structure including a plurality of light-emitting units 30 can be manufactured first. For example, the plurality of light-emitting units 30 in the light-emitting structure are arranged in an array, and the plurality of light-emitting units 30 in the same row are connected in series one by one, so as to facilitate the testing of the plurality of light-emitting units 30. For example, the first protruding part 3111 of one of the two adjacent light-emitting units 30 and the second electrode 312 of the other light-emitting unit 30 are in an integrated structure. Correspondingly, the first inner edge E01 of the first protruding part 3111 extends along the third direction, that is, the first inner edge E01 of the first protruding part 3111 is inclined to the first main body part 3110, so as to be electrically connected with the second electrode 312 of the other light-emitting unit 30. Meanwhile, the fourth edge E4 is arranged to extend along the third direction, so that the fourth edge E4 and the first protruding part 3111 of the first electrode 311 can leave a sufficient gap while ensuring that the second electrode 312 has a sufficient area.

[0115] In some embodiments, as shown in FIGS. 7A-9B, the first inner edge E01 of the first protruding part 3111 extends along the third direction, and in addition, the second conductive pad 212 includes a first edge E1 facing the second main body part 2110 and a second edge E2 connected with the first edge E1, the first edge E1 extends along the first direction, and the second edge E2 is arranged opposite to the third protruding part 2111. The third protruding part 2111 has a second inner edge E02 connected with the second main body part 2110 and facing the second edge E2, and the second edge E2 and the second inner edge E02 both extend along the third direction, so that the third protruding part 2111 and the fourth edge E4 can leave a sufficient gap while ensuring that the solder part 40 on the third protruding part 2111 can fully cover the first protruding part 3111.

[0116] For example, in FIGS. 7A, 8A and 9A, the second inner edge E02 of the third protruding part 2111 and the second edge E2 of the second conductive pad 212 have a gap of 0.3 mm, and the gap between the first inner edge E01 of the first protruding part 3111 and the fourth edge E4 of the second electrode 312 is greater than 0.3 mm.

[0117] In some embodiments, as shown in FIGS. 7A, 8A and 9A, the second electrode 312 can further include a fifth edge E5 connected with the third edge E3, and at least a part of the fifth edge E5 forms a recess, which is conducive to the solder part 40 on the second conductive pad 212 covering the side surface of the second electrode 312 at the recessed position of the fifth edge E5, and further reducing the silver exposed area.

[0118] FIG. 10A is a plan view of the light emitting unit 30 and the conductive pad 21 provided in yet some embodiments of the present disclosure, the plan view of the conductive pad 21 is shown in (a) of FIG. 10A, the plan view of the electrode 31 of the light emitting unit 30 is shown in (b) of FIG. 10A, the plan view of the solder part 40 is shown in (c) of FIG. 10A, and the plan view of the conductive pad 21 and the solder part 40 after being superimposed is shown in (d) of FIG. 10A. FIG. 10B is a plan view of the light emitting unit 30 and the conductive pad 21 after being superimposed, which is the same as FIGS. 7A-9B. In FIGS. 10A and 10B, the plurality of electrodes 31 of the light emitting unit 30 includes the first electrode 311 and the second electrode 312, and the plurality of conductive pads 21 includes the first conductive pad 211 electrically connected to the first electrode 311 and the second conductive pad 212 electrically connected to the second electrode 312. The first conductive pad 211 includes the second body part 2110 and the third protruding part 2111 connected to the side of the second body part 2110 facing the second conductive pad 212.

[0119] The conductive pad 21 is superimposed on the solder part 40, and the normal projection of the conductive pad 21 on the substrate 10 is located within the normal projection range of the solder part 40 on the substrate 10, and the distance between the normal projection edge of the conductive pad 21 and the normal projection edge of the solder part 40 is less than or equal to 0.16 mm. The normal projection of the electrode 31 on the substrate 10 is located within the normal projection range of the solder part 40 on the substrate 10, for example, the normal projection of the electrode 31 on the substrate 10 is located within the normal projection range of the conductive pad 21 on the substrate 10; for another example, the normal projection of the electrode 31 on the substrate 10 can exceed the normal projection of the conductive pad 21 on the substrate 10, but the exceeding distance is less than or equal to 0.16 mm.

[0120] Different from FIGS. 7A-9B, in FIGS. 10A and 10B, the light emitting unit 30 includes a plurality of first electrodes 311, for example, the light emitting unit 30 includes two first electrodes 311. The plurality of first electrodes 311 are located on the same side of the second electrode 312 and arranged along the first direction, and the first conductive pad 211 is electrically connected to the first electrode 311 one by one. The normal projection of the first electrode 311 on the substrate 10 is located within the normal projection range of the corresponding first conductive pad 211 on the substrate 10, so as to ensure that the solder part 40 formed on the first conductive pad 211 can sufficiently cover the surface of the first electrode 311 facing the substrate 10. In other embodiments, a part of the normal projection of the first electrode 311 on the substrate 10 can exceed the normal projection of the first conductive pad 211 on the substrate 10, and the distance between the edge of the exceeding part and the normal projection edge of the first conductive pad 211 is less than or equal to 0.16 mm. In this case, during the reflow soldering process, the solder climbs along the first electrode 311, and the finally formed solder part 40 can also cover the surface of the first electrode 311 facing the substrate 10.

[0121] Exemplarily, as shown in FIGS. 10A and 10B, the second conductive pad 212 has a second recessed portion 212a corresponding to each third protruding portion 2111 toward the edge of the first conductive pad 211, and the second recessed portion 212a is oppositely arranged with the corresponding third protruding portion 2111 in the second direction. By arranging the second recessed portion 212a, a clearance space for avoiding the third protruding portion 2111 can be provided, so that the third protruding portion 2111 and the second conductive pad 212 have sufficient spacing, thereby preventing the first conductive pad 211 and the second conductive pad 212 from short-circuiting.

[0122] Exemplarily, as shown in FIGS. 10A and 10B, the light emitting unit 30 is electrically connected with two first conductive pads 211, and among the two third protruding portions 2111 of the two first conductive pads 211, each third protruding portion 2111 is arc-shaped toward the edge of the other third protruding portion 2111, and the distance between the opposite two edges of the two third protruding portions 2111 gradually increases along the direction from the first conductive pad 211 to the second conductive pad 212. This arrangement can ensure that the first conductive pad 211 has a large enough area while having sufficient safety distance between the first conductive pad 211 and the second conductive pad 212.

[0123] Exemplarily, in FIG. 10B, the orthographic projection of the first electrode 311 on the substrate 10 can be located within the orthographic projection range of the first conductive pad 211 on the substrate 10, and the orthographic projection of the second electrode 312 on the substrate 10 can be located within the orthographic projection range of the second conductive pad 212 on the substrate 10.

[0124] Exemplarily, in FIGS. 10A and 10B, the closest distance between the first conductive pad 211 and the second electrode 312 is 0.3 mm, and the closest distance between the first conductive pad 211 and the second conductive pad 212 is greater than 0.3 mm.

[0125] The display device provided by the embodiments of the present disclosure can be used in a display device.

[0126] In one example, the display device includes a backlight module and a display panel located on the light emitting side of the backlight module, and the backlight module includes the light emitting substrate.

[0127] FIG. 11 is a schematic diagram of a display device provided in some embodiments of the present disclosure, as shown in FIG. 11, the backlight module includes a middle frame 300, a back plate 200, a diffusion sheet 501, and an optical film 502, the back plate 200 is fixedly connected with the middle frame 300, the light-emitting substrate is located on the back plate 200, the middle frame 300 includes a blocking wall 303, and a first bearing part 301 and a second bearing part 302 connected with the blocking wall 303, the edge of the diffusion sheet 501 is supported on the first bearing part 301, and the optical film 502 is located on the side of the diffusion sheet 501 away from the back plate 200. The edge of the display panel 400 is supported on the second bearing part 302, and the light-emitting substrate can further include a support 70, the support 70 is located on the substrate 10 and supports the diffusion sheet 501.

[0128] In another example, the display device includes a display panel, and the display panel includes the light-emitting substrate described above.

[0129] It can be understood that the above implementation is only an exemplary implementation adopted for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the present disclosure.

Claims

1. A light emitting substrate, comprising: a substrate; a driving layer disposed on the substrate, the driving layer having a plurality of conductive pads; a plurality of light emitting units located on a side of the driving layer distal to the substrate, the light emitting units having a plurality of electrodes, each of the electrodes being electrically connected to one of the conductive pads through a corresponding solder portion, the solder portion including silver therein; wherein a projection of the electrode on the substrate is within a projection range of the solder portion on the substrate, or, A part of the orthogonal projection of the electrode on the substrate is a first overhang region, the electrode comprises a first metal layer located in the first overhang region, the material of the first metal layer comprises silver; the first overhang region is located outside the orthogonal projection of the solder part on the substrate, and the area S of the first overhang region satisfies: wherein the electrodes of the light emitting units include a first electrode and a second electrode, and L is a minimum distance between the first electrode and the second electrode.

2. The light-emitting substrate according to claim 1, wherein L is within a range of 0.1-0.3 mm.

3. The light-emitting substrate of claim 1, wherein, a projection of the conductive pad on the substrate is within a projection range of the corresponding solder portion on the substrate, and a distance between a projection edge of the conductive pad and a projection edge of the solder portion is less than or equal to 0.16 mm.

4. The light emitting substrate of claim 1, wherein, the electrode includes a first surface facing the substrate, a second surface facing away from the substrate, and a first side surface connecting the first surface and the second surface, at least a portion of the first side surface being in contact with the solder portion.

5. The light-emitting substrate according to any one of claims 1 to 4, wherein the electrode includes a second metal layer, a material of the second metal layer including a second metal, the second metal including copper; and a material of the solder portion including an alloy of silver, the second metal, and tin; wherein the second metal layer is in direct contact with the solder portion, or, the electrode further includes a third metal layer between the second metal layer and the solder portion, a material of the third metal layer including silver.

6. The light-emitting substrate of claim 5, wherein, the electrode includes a first metal layer in a first overhanging region, and the electrode further includes a third metal layer; the third metal layer is integrated with the first metal layer as an integral structure.

7. The light-emitting substrate according to any one of claims 1 to 4, wherein the first electrode includes a first main body portion extending in a first direction, and a first protruding portion and a second protruding portion connected to a side of the first main body portion facing the second electrode, the first protruding portion and the second protruding portion being arranged in the first direction; a dimension of the first protruding portion in a second direction is greater than a dimension of the second protruding portion in the second direction; the second direction is a direction from the first electrode to the second electrode, and the first direction is perpendicular to the second direction; a projection of the second protruding portion on the substrate is within a projection range of the corresponding solder portion on the substrate.

8. The light-emitting substrate of claim 7, wherein, the plurality of conductive pads include a first conductive pad electrically connected to the first electrode, and a second conductive pad electrically connected to the second electrode; the first conductive pad includes a second main body portion extending in the first direction, and at least one third protruding portion connected to a side of the second main body portion facing the second conductive pad, a projection of the second main body portion on the substrate overlapping a projection of the first main body portion on the substrate; wherein a projection of the first protruding portion on the substrate is within a projection range of one of the third protruding portions on the substrate, or a projection of the first protruding portion on the substrate partially overlaps a projection of one of the third protruding portions on the substrate.

9. The light-emitting substrate of claim 7, wherein, The plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode; The first conductive pad includes a second main body portion extending along the first direction and at least one third protruding portion connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps with a projection of the first main body portion on the substrate; A part of a projection of the second protruding portion on the substrate is a second overhanging area, the second overhanging area is located outside the projection of the first conductive pad on the substrate, and a maximum distance between an edge of the second overhanging area and an edge of the projection of the first conductive pad is not more than 0.16 mm.

10. The light emitting substrate of claim 7, wherein, The plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode; The first conductive pad includes a second main body portion extending along the first direction and two third protruding portions connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps with a projection of the first main body portion on the substrate; The projection of the second protruding portion on the substrate is located within a projection range of one of the third protruding portions on the substrate, and the projection of the first protruding portion on the substrate overlaps with a projection of the other third protruding portion on the substrate.

11. The light-emitting substrate of claim 7, wherein, The plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode; The first conductive pad includes a second main body portion extending along the first direction and at least one third protruding portion connected to a side of the second main body portion facing the second conductive pad, and a projection of the second main body portion on the substrate overlaps with a projection of the first main body portion on the substrate; At least one of the first protruding portion and the second protruding portion has a projection on the substrate that overlaps with a projection of the third protruding portion on the substrate; The first protruding portion faces a first inner edge of the second main body portion, and the first inner edge extends along a third direction; The second conductive pad includes a first edge facing the second main body portion and a second edge connected to the first edge, the first edge extends along the first direction, and the second edge is opposite to the third protruding portion; the third protruding portion has a second inner edge facing the second edge, and the second inner edge and the second edge both extend along the third direction, the third direction intersects with the first direction and intersects with the second direction.

12. The light-emitting substrate of claim 7, wherein, The second electrode has a third edge facing the first main body portion and a fourth edge connected to the third edge, the third edge includes a straight line portion and a first recess portion, the straight line portion is in the same direction as the first main body portion, and the first recess portion is opposite to the second protruding portion and curves away from the second protruding portion; The first protruding part has a first inner edge facing the second protruding part; the fourth edge is arranged opposite to the first protruding part, and the fourth edge and the first inner edge both extend along a third direction, the third direction being perpendicular to the extending direction of the first body part and perpendicular to the second direction.

13. The light-emitting substrate according to any one of claims 1 to 4, wherein, The plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode. The first conductive pad includes a second body part and a third protruding part connected to one side of the second body part facing the second conductive pad, and the light emitting unit includes a plurality of the first electrodes arranged on the same side of the second electrode along a first direction, the first conductive pad being electrically connected to the first electrode one by one. The first electrode has a projection on the substrate within the projection range of the first conductive pad on the substrate, or the projection of the first electrode covers and exceeds the projection of the first conductive pad on the substrate, and the distance between the projection edge of the first electrode and the projection edge of the first conductive pad is less than or equal to 0.16 mm.

14. The light-emitting substrate of claim 13, wherein, The edge of the second conductive pad facing the first conductive pad has a second recess part corresponding to the third protruding part one by one, and the second recess part is arranged opposite to the corresponding third protruding part in a second direction, the second direction being the direction from the first electrode to the second electrode.

15. The light-emitting substrate of claim 13, wherein, The light emitting unit is electrically connected to two first conductive pads, and the edge of each third protruding part of the two third protruding parts of the two first conductive pads facing the other third protruding part is arc-shaped, and the distance between the opposite two edges of the two third protruding parts gradually increases along the direction from the first conductive pad to the second conductive pad.

16. The light-emitting substrate according to any one of claims 1 to 4, wherein, The plurality of conductive pads includes a first conductive pad electrically connected to the first electrode and a second conductive pad electrically connected to the second electrode; and the minimum distance between the first conductive pad and the second conductive pad is within the range of 0.1-0.3 mm.

17. A display device comprising the light emitting substrate according to any one of claims 1-16.

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