Light-emitting substrate, manufacturing method of light-emitting substrate, backlight module and display device

Abstract

The invention discloses a light-emitting substrate, a manufacturing method of the light-emitting substrate, a backlight module and a display device. The light-emitting substrate comprises a substrate body, a first passivation layer, a metal layer and a second passivation layer. The first passivation layer is located on the substrate base plate; the metal layer is located at one side, far away from the substrate, of the first passivation layer; the second passivation layer at least covers the partial surface, far away from the substrate, of the metal layer, the surface, not parallel to the substrate, of the metal layer, and the partial surface, not parallel to the substrate, of the first passivation layer; the plane where the surface, closest to the substrate, of the second passivation layer is located is located between the surface, close to the substrate, of the metal layer and the substrate.

Description

Technical Field

[0001] The present application belongs to the field of display technology, and specifically relates to a light-emitting substrate and a manufacturing method thereof, a backlight module, and a display device. Background Art

[0002] Micro LED (Light Emitting Diode) includes Mini LED and Micro LED. Mini LED refers to LED chips with a grain size of 100 to 300 microns. Micro LED refers to LED chips with a grain size of less than 100 microns.

[0003] In current product designs, an opening is set in the insulating layer covering the metal traces so that the pads of the LED chip can be connected to the metal traces through the openings. Since the grain size of the micro-LED is very small, the distance between the metal traces connecting the two pads of the micro-LED is very close. When the metal traces in the opening area are corroded, the volume of the metal traces expands and migrates outward, causing the metal wires connecting the two pads of the micro-LED to be connected, resulting in a short circuit in the micro-LED. Summary of the invention

[0004] The present application provides a light-emitting substrate and a manufacturing method thereof, a backlight module, and a display device, aiming to solve the problem of micro-LED short circuit caused by metal wiring corrosion to at least a certain extent.

[0005] In a first aspect of the present application, a light-emitting substrate is provided, the light-emitting substrate comprising: substrate substrate; A first passivation layer, located on the substrate; A metal layer, located on a side of the first passivation layer away from the substrate; The second passivation layer at least covers a portion of the surface of the metal layer away from the substrate, a surface of the metal layer not parallel to the substrate, and a portion of the surface of the first passivation layer not parallel to the substrate; the plane where the surface of the second passivation layer closest to the substrate is located is located between the surface of the metal layer close to the substrate and the substrate.

[0006] In some embodiments, the second passivation layer includes a step structure, and the surface of the step structure close to the substrate includes at least two treads and at least one riser, the treads and the risers are alternately connected, and the treads are parallel to the substrate; the tread of the step structure farthest from the substrate is in contact with a portion of the surface of the metal layer away from the substrate; the riser is in contact with a surface of the metal layer that is not parallel to the substrate, and a surface of the first passivation layer that is not parallel to the substrate; the plane where the tread of the step structure closest to the substrate is located is located between the surface of the metal layer close to the substrate and the substrate.

[0007] In some embodiments, the metal layer includes at least two metal wires spaced apart; the second passivation layer includes at least two step structures, each step structure corresponding to one of the metal wires; the surface of the step structure close to the substrate is in contact with the surface of the corresponding metal wire; the plane where the tread of the step structure closest to the substrate is located is located between the surface of the corresponding metal wire close to the substrate and the substrate.

[0008] In some embodiments, the first passivation layer has at least one first opening; the orthographic projection of the first opening on the substrate does not overlap with the orthographic projection of the metal line on the substrate; the step structure is partially located in the first opening; or, the first passivation layer has at least one first groove recessed toward the substrate; the orthographic projection of the first groove on the substrate does not overlap with the orthographic projection of the metal line on the substrate; the step structure is partially located in the first groove.

[0009] In some embodiments, the step structure includes at least two steps.

[0010] In some embodiments, an orthographic projection of the first opening or the first groove on the substrate is spaced apart from an orthographic projection of the metal line on the substrate.

[0011] In some embodiments, the light-emitting substrate further comprises: A planar layer, located between the first passivation layer and the substrate; The planar layer has at least one second opening, and the second opening corresponds to the first opening or the first groove; the orthographic projection of the second opening on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate; the first passivation layer is partially located in the second opening; or, The flat layer has at least one second groove recessed toward the base substrate, and the second groove corresponds to the first opening or the first groove; the orthographic projection of the second groove on the base substrate covers the orthographic projection of the corresponding first opening or the first groove on the base substrate; the first passivation layer is partially located in the second groove.

[0012] In some embodiments, an orthographic projection of the second opening or the second groove on the base substrate does not overlap with an orthographic projection of the metal line on the base substrate.

[0013] In some embodiments, the planar layer includes at least two planar sub-layers stacked in sequence in a direction away from the base substrate; each of the planar sub-layers has a sub-opening corresponding to the second opening one by one, and the sub-openings of each of the planar sub-layers are connected one by one to form a corresponding second opening.

[0014] In some embodiments, at least two of the step structures include a first step structure and a second step structure, the metal wire corresponding to the first step structure is a first metal wire, the metal wire corresponding to the second step structure is a second metal wire, the first metal wire and the second metal wire are two adjacent metal wires among the at least two metal wires; the orthographic projection of the first opening or the first groove on the substrate is at least located between the orthographic projection of the first metal wire on the substrate and the orthographic projection of the second metal wire on the substrate; the riser surface of the first step structure contacts the surface of the first metal wire close to the second metal wire; the riser surface of the second step structure contacts the surface of the second metal wire close to the first metal wire.

[0015] In some embodiments, the light-emitting substrate further comprises: A third passivation layer, located between the planar layer and the substrate; The third passivation layer has at least one third opening, and the third opening corresponds to the second opening; the orthographic projection of the third opening on the substrate is located within the orthographic projection of the corresponding second opening on the substrate; the first passivation layer and / or the second passivation layer are partially located within the third opening; or, The third passivation layer has at least one third groove sunken toward the base substrate, and the third groove corresponds to the second opening; the orthographic projection of the third groove on the base substrate is located within the orthographic projection of the corresponding second opening on the base substrate; the first passivation layer and / or the second passivation layer are partially located in the third groove.

[0016] In some embodiments, an orthographic projection edge of the third opening or the third groove on the substrate is spaced apart from an orthographic projection edge of the corresponding second opening on the substrate.

[0017] In some embodiments, a tread of the first step structure that is closest to the substrate is connected to a tread of the second step structure that is closest to the substrate.

[0018] In some embodiments, the surface of the first metal line close to the substrate and the surface of the second metal line close to the substrate are located in the same plane parallel to the substrate; the first step structure and the second step structure are mirror-symmetric relative to a reference plane perpendicular to the substrate.

[0019] In a second aspect of the present application, a backlight module is provided. The backlight module includes the light-emitting substrate provided in the first aspect.

[0020] In a third aspect of the present application, a display device is provided, comprising a display panel and a backlight module as provided in the second aspect.

[0021] In a fourth aspect of the present application, a method for manufacturing a light-emitting substrate is provided, the method comprising: Providing a substrate; forming a first passivation layer on the base substrate, wherein the first passivation layer has a first opening or a first groove; forming a metal layer on the first passivation layer; wherein an orthographic projection of the metal layer on the base substrate does not overlap with an orthographic projection of the first opening or the first groove on the base substrate; A second passivation layer is formed on the metal layer and in the first opening or the first groove, wherein the second passivation layer at least covers a portion of the surface of the metal layer away from the substrate, a surface of the metal layer that is not parallel to the substrate, and a portion of the surface of the first passivation layer that is not parallel to the substrate; a surface of the second passivation layer that is closest to the substrate is located between a surface of the metal layer close to the substrate and the substrate.

[0022] In some embodiments, before forming the first passivation layer on the substrate, the manufacturing method further includes: forming a planar layer on the base substrate; The flat layer is etched to form a second opening or a second groove; the second opening corresponds to the first opening or the first groove, and the orthographic projection of the second opening on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate; the second groove corresponds to the first opening or the first groove, and the orthographic projection of the second groove on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate.

[0023] In some embodiments, before forming the planar layer on the base substrate, the manufacturing method further includes: forming a third passivation layer on the base substrate; After etching the planar layer to form the second opening, the manufacturing method further includes: The third passivation layer is etched to form a third opening or a third groove; the third opening corresponds to the second opening, and the orthographic projection of the third opening on the substrate is located within the orthographic projection of the corresponding second opening on the substrate; the third groove corresponds to the second opening, and the orthographic projection of the third groove on the substrate is located within the orthographic projection of the corresponding second opening on the substrate.

[0024] According to the light-emitting substrate and its manufacturing method, backlight module and display device provided by one or more embodiments of the present application, a first passivation layer, a metal layer and a second passivation layer are sequentially arranged on the base substrate, and the second passivation layer covers the surface of the metal layer from the part of the surface far away from the base substrate, through the surface of the metal layer that is not parallel to the base substrate, to the part of the surface of the first passivation layer that is not parallel to the base substrate, so that the plane where the surface of the second passivation layer closest to the base substrate is located is located between the surface of the metal layer close to the base substrate and the base substrate, so that even if the volume of the wiring in the metal layer migrates outward during corrosion, the migration channel is not between the metal wirings connected to the two pads of the micro LED, so that the micro LED will not be short-circuited, thereby effectively reducing the risk of product short-circuit and improving product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A partial structural schematic diagram of a light-emitting substrate in the related art is shown.

[0027] Figure 2 Shows Figure 1A top view of the light-emitting substrate along the AA direction.

[0028] Figure 3 A schematic diagram of metal wiring corrosion in the related art is shown.

[0029] Figure 4 A schematic diagram of pad connectivity in the related art is shown.

[0030] Figure 5 A partial structural schematic diagram of a light-emitting substrate in an embodiment of the present application is shown.

[0031] Figure 6 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0032] Figure 7 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0033] Figure 8 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0034] Fig. 9 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0035] Fig.10 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0036] Fig.11 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0037] Fig.12 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0038] Fig.13 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0039] Fig.14 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0040] Fig.15 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0041] Fig.16 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0042] Fig.17 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0043] Fig.18 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0044] Fig.19 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0045] Fig. 20 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0046] Fig.21 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0047] Fig. 22 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0048] Fig.23 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0049] Fig.24 A partial structural schematic diagram of a light-emitting substrate in another embodiment of the present application is shown.

[0050] Fig.25 Shows Fig.23 A top view of the light-emitting substrate along direction BB.

[0051] Fig.26 A flow chart of a method for manufacturing a light-emitting substrate in one or more embodiments of the present application is shown.

[0052] Fig. 27 A flow chart of a method for manufacturing a light-emitting substrate in an embodiment of the present application is shown.

[0053] Description of reference numerals: 1': glass substrate; 2': buffer layer; 31': first insulating layer; 32': second insulating layer; 33': third insulating layer; 41': first flat layer; 42': second flat layer; 43': third flat layer; 5': metal trace; 6': LED pad; 1: substrate; 2: first passivation layer; 21: first opening; 22: first groove; 3: metal layer; 30: metal line; 31: first metal line; 32: second metal line; 4: second passivation layer; 40: step structure; 41: first step structure; 42: second step structure; 401: tread; 402: riser; 5: flat layer; 50: flat sublayer; 51: second opening; 52: second groove; 6: third passivation layer; 61: third opening; 62: third groove; 7: buffer layer; 8: pad; 9: filling layer. DETAILED DESCRIPTION

[0054] In order to make the technical personnel in the technical field to which the present application belongs to understand the present application more clearly, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0055] See also Figure 1 In the related art, a light-emitting substrate using micro LED to realize backlight includes a glass substrate 1', a buffer layer 2', a first insulating layer 31', a second insulating layer 32', a third insulating layer 33', a first flat layer 41', a second flat layer 42', a third flat layer 43', a metal trace 5' and an LED pad 6'. The buffer layer 2', the first insulating layer 31', the first flat layer 41', the second flat layer 42' and the second insulating layer 32' are stacked in sequence on the glass substrate 1'. At least two metal traces 5' are arranged at intervals on the surface of the second insulating layer 32' away from the glass substrate 1', and part of the surface of the second insulating layer 32' is exposed. The third insulating layer 33' covers the metal trace 5' and the exposed second insulating layer 32', and an opening is provided in the third insulating layer 33' covering the side of the metal trace 5' away from the glass substrate 1'. The LED pad 6' is arranged on the metal trace 5' through the opening of the third insulating layer 33' and extends out from the opening of the third insulating layer 33'. The third planar layer 43 ′ covers the third insulating layer 33 ′ to fill the space except the LED pad 6 ′.

[0056] See also Figure 2 Since the grain size of micro LED is very small, the distance between two LED pads 6' belonging to one micro LED is very close, and the distance between the metal traces 5' connected to the two LED pads 6' is only 42μm. The material of the metal trace 5' is usually Cu2. When the metal trace 5' at the opening of the third insulating layer 33' is corroded, the volume of the metal trace 5' expands and migrates to the gap between the third insulating layer 33' and the second insulating layer 32' below it, thereby expanding the gap and forming a channel between two adjacent metal traces 5', such as Figure 3The metal traces 5' connected to the two LED pads 6' of a micro LED can be connected through this channel, so that the two LED pads 6' (ie, the P-type pad and the N-type pad) of a micro LED are connected, causing the micro LED to short-circuit. Figure 4 shown.

[0057] See also Figure 5 In a first aspect of the present application, a light-emitting substrate is provided, comprising a substrate 1, a first passivation layer 2, a metal layer 3, and a second passivation layer 4. The first passivation layer 2 is located on the substrate 1. The metal layer 3 is located on the side of the first passivation layer 2 away from the substrate 1. The second passivation layer 4 at least covers a portion of the surface of the metal layer 3 away from the substrate 1, a surface of the metal layer 3 that is not parallel to the substrate 1, and a portion of the surface of the first passivation layer 2 that is not parallel to the substrate 1. The plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1.

[0058] The above-mentioned light-emitting substrate includes a base substrate 1, a first passivation layer 2, a metal layer 3 and a second passivation layer 4, the first passivation layer 2 is located on the base substrate 1, the metal layer 3 is located on the side of the first passivation layer 2 away from the base substrate 1, the second passivation layer 4 at least covers a portion of the surface of the metal layer 3 away from the base substrate 1, a surface of the metal layer 3 not parallel to the base substrate 1, and a portion of the surface of the first passivation layer 2 not parallel to the base substrate 1, and a plane where the surface of the second passivation layer 4 closest to the base substrate 1 is located is located between the surface of the metal layer 3 close to the base substrate 1 and the base substrate 1, so that even if the wiring in the metal layer 3 is corroded, the volume expands and expands outward, it can only migrate along the surface of the first passivation layer 2 not parallel to the base substrate 1, and it is difficult to form a migration channel between the metal wirings connected to the two pads of the micro LED, thereby effectively avoiding the connection between the two pads of the micro LED, reducing the risk of short circuit of the micro LED, and improving product reliability.

[0059] See also Figure 6 In some embodiments, the second passivation layer 4 may include a step structure 40, and the surface of the step structure 40 close to the substrate substrate 1 includes at least two treads 401 and at least one riser 402, the treads 401 and the riser 402 are alternately connected, and the treads 401 are parallel to the substrate substrate 1. The tread 401 of the step structure 40 farthest from the substrate substrate 1 contacts the surface of the metal layer 3 far from the substrate substrate 1. The riser 402 contacts the surface of the metal layer 3 that is not parallel to the substrate substrate 1, and the surface of the first passivation layer 2 that is not parallel to the substrate substrate 1. The plane where the tread 401 of the step structure 40 closest to the substrate substrate 1 is located is located between the surface of the metal layer 3 close to the substrate substrate 1 and the substrate substrate 1.

[0060] In the above embodiment, the second passivation layer 4 includes a step structure 40, and the surface of the step structure 40 close to the substrate substrate 1 includes a tread 401 and a riser 402, and the riser 402 is in contact with the surface of the metal layer 3 that is not parallel to the substrate substrate 1, and the surface of the first passivation layer 2 that is not parallel to the substrate substrate 1. In this way, even if the wiring in the metal layer 3 is corroded and the volume expands and migrates along the surface of the first passivation layer 2 that is not parallel to the substrate substrate 1 to the side of the first passivation layer 2 close to the substrate substrate 1, the step structure 40 is still covered by the tread 401 closest to the substrate substrate 1, which can effectively prevent the second passivation layer 4 from being expanded by the metal layer 3, thereby improving product reliability.

[0061] Exemplarily, the riser 402 of the metal layer 3 that is not parallel to the surface of the substrate 1 and the riser 402 of the first passivation layer 2 that is not parallel to the surface of the substrate 1 can be the same surface or different surfaces. The riser 402 of the step structure 40 that is farthest from the substrate 1 at least contacts the surface of the metal layer 3 that is not parallel to the substrate 1. The riser 402 of the step structure 40 that is closest to the substrate 1 at least contacts the surface of the first passivation layer 2 that is not parallel to the substrate 1.

[0062] See also Figure 5 In other possible embodiments, the second passivation layer 4 may also include an inverted L-shaped structure, and the surface of the inverted L-shaped structure close to the substrate 1 includes a first surface and a second surface that are not parallel to each other, the first surface contacts a portion of the surface of the metal layer 3 away from the substrate 1, and the second surface contacts a surface of the metal layer 3 that is not parallel to the substrate 1, as well as a surface of the first passivation layer 2 that is not parallel to the substrate 1.

[0063] See also Figure 7 In some embodiments, the step structure 40 may include at least two steps. In this case, the surface of the step structure 40 close to the substrate 1 includes at least two risers 402. The riser 402 of the step structure 40 farthest from the substrate 1 contacts the surface of the metal layer 3 that is not parallel to the substrate 1. The riser 402 of the step structure 40 closest to the substrate 1 contacts the surface of the first passivation layer 2 that is not parallel to the substrate 1.

[0064] In the above embodiment, the step structure 40 may include at least two steps, the metal layer 3 is not parallel to the surface of the substrate 1, and the first passivation layer 2 is not parallel to the surface of the substrate 1, and contacts with different risers 402 respectively. In addition, the tread 401 connecting the two adjacent risers 402 makes it possible for the wiring in the metal layer 3 to corrode and expand outward, and can only migrate along the alternately connected and non-parallel risers 402 and treads 401, which greatly increases the difficulty of migration of the wiring in the metal layer 3, and makes it impossible for the metal wiring connected to the two pads of the micro LED to form a migration channel and be connected, which effectively reduces the risk of short circuit of the micro LED and further improves the product reliability.

[0065] See also Figure 6 In other possible embodiments, the step structure 40 may also include only one step. In this case, the surface of the step structure 40 close to the substrate 1 only includes one riser 402. The riser 402 is in contact with the surface of the metal layer 3 that is not parallel to the substrate 1 and the surface of the first passivation layer 2 that is not parallel to the substrate 1.

[0066] See also Figure 8 In some embodiments, the metal layer 3 may include at least two spaced metal wires 30. The second passivation layer 4 includes at least two step structures 40, each step structure 40 corresponding to a metal wire 30. The surface of the step structure 40 close to the substrate 1 is in contact with the surface of the corresponding metal wire 30. The plane where the tread 401 of the step structure 40 closest to the substrate 1 is located is located between the surface of the corresponding metal wire 30 close to the substrate 1 and the substrate 1.

[0067] In the above embodiment, the metal layer 3 includes at least two metal wires 30 arranged at intervals, and the second passivation layer 4 is provided with a step structure 40 corresponding to the metal wires 30, so that any metal wire 30 is corroded, expands in volume and expands outward, and can only migrate along the surface of the first passivation layer 2 which is not parallel to the substrate 1, and it is difficult to form a migration channel between the metal traces connecting the two pads of the micro LED, thereby effectively avoiding the two pads of the micro LED from being connected, reducing the risk of short circuit of the micro LED, and improving product reliability.

[0068] See also Figure 8 , illustratively, the tread surface 401 of the step structure 40 farthest from the substrate 1 contacts the surface of the corresponding metal wire 30 away from the substrate 1. The riser surface 402 of the step structure 40 farthest from the substrate 1 contacts at least the surface of the corresponding metal wire 30 that is not parallel to the substrate 1.

[0069] For example, the number of step structures 40 corresponding to a metal line 30 can be set according to actual needs, such as the number of adjacent metal lines 30, the number of connecting pads, etc. For example, if a metal line 30 is adjacent to only one metal line 30, it can correspond to only one step structure 40. For another example, if a metal line 30 is connected to multiple pads, it can also correspond to multiple step structures 40, and the number of corresponding step structures 40 is consistent with the number of connecting pads.

[0070] See also Fig. 9 In some embodiments, at least two step structures 40 may include a first step structure 41 and a second step structure 42. The metal wire 30 corresponding to the first step structure 41 is the first metal wire 31, and the metal wire 30 corresponding to the second step structure 42 is the second metal wire 32. The first metal wire 31 and the second metal wire 32 are two adjacent metal wires 30 among the at least two metal wires 30. The riser 402 of the first step structure 41 contacts the surface of the first metal wire 31 close to the second metal wire 32. The riser 402 of the second step structure 42 contacts the surface of the second metal wire 32 close to the first metal wire 31.

[0071] In the above embodiment, the step structures 40 corresponding to two adjacent metal wires 30 are located between the two adjacent metal wires 30, which can effectively prevent the two pads of the micro LED from being connected, reduce the risk of short circuit of the micro LED, and improve product reliability.

[0072] See also Figure 8 In other possible embodiments, the riser surface 402 of each step structure 40 may contact the same side surface of the corresponding metal wire 30. For example, the riser surface 402 of the first step structure 41 contacts the surface of the first metal wire 31 close to the second metal wire 32, and the riser surface 402 of the second step structure 42 contacts the surface of the second metal wire 32 away from the first metal wire 31. Alternatively, the riser surface 402 of the first step structure 41 contacts the surface of the first metal wire 31 away from the second metal wire 32, and the riser surface 402 of the second step structure 42 contacts the surface of the second metal wire 32 close to the first metal wire 31.

[0073] See also Fig.10 For example, the tread 401 of the first step structure 41 closest to the substrate 1 can be connected to the tread 401 of the second step structure 42 closest to the substrate 1. This is conducive to simplifying the process design, reducing the process steps, and reducing the implementation cost.

[0074] See also Fig. 9 In other possible embodiments, the tread 401 of the first step structure 41 that is closest to the substrate 1 may also be disconnected from the tread 401 of the second step structure 42 that is closest to the substrate 1 .

[0075] See also Fig. 9 and Fig.10 For example, the surface of the first metal line 31 close to the substrate 1 can be located in the same plane parallel to the substrate 1 as the surface of the second metal line 32 close to the substrate 1. The first step structure 41 and the second step structure 42 can be mirror-symmetrical with respect to a reference plane perpendicular to the substrate 1. This is conducive to simplifying the process design, reducing the process steps, and reducing the implementation cost.

[0076] In other possible embodiments, the first step structure 41 and the second step structure 42 may also be asymmetric structures, such as the first step structure 41 includes only one step, and the second step structure 42 includes two steps.

[0077] See also Fig. 9 and Fig.10 In a possible embodiment, the first passivation layer 2 may have at least one first opening 21 . The orthographic projection of the first opening 21 on the substrate 1 does not overlap with the orthographic projection of the metal line 30 on the substrate 1 . The step structure 40 is partially located in the first opening 21 .

[0078] In the above embodiment, the first opening 21 is provided at a position where the metal wire 30 is not provided in the first passivation layer 2 to accommodate part of the step structure 40, so that the second passivation layer 4 can cover part of the surface of the first passivation layer 2 which is not parallel to the substrate 1, and then the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1, thereby preventing the metal wires 30 respectively connected to the two pads of the micro LED from being connected, thereby improving the reliability of the product.

[0079] See also Fig. 9 and Fig.10 , illustratively, the orthographic projection of the first opening 21 on the substrate 1 can be located between the orthographic projection of the first metal line 31 on the substrate 1 and the orthographic projection of the second metal line 32 on the substrate 1. By setting the first opening 21 between two adjacent metal lines 30, the step structures 40 corresponding to the two adjacent metal lines 30 pass through the same first opening 21, so that the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1, effectively preventing the metal lines 30 connected to the two pads of the micro LED from being connected, thereby improving product reliability.

[0080] See also Fig.11For example, the orthographic projection of the first opening 21 on the base substrate 1 can be spaced apart from the orthographic projection of the metal wire 30 on the base substrate 1. By staggering the edge of the first opening 21 and the edge of the metal wire 30, the step structure 40 includes at least two steps, thereby effectively preventing the metal wires 30 connected to the two pads of the micro LED from being connected, further improving product reliability.

[0081] See also Fig.12 In another possible embodiment, the first passivation layer 2 may have at least one first groove 22 recessed toward the base substrate 1. The orthographic projection of the first groove 22 on the base substrate 1 does not overlap with the orthographic projection of the metal line 30 on the base substrate 1. The step structure 40 is partially located in the first groove 22.

[0082] In the above embodiment, the first groove 22 is provided at the position where the metal wire 30 is not provided in the first passivation layer 2 to accommodate part of the step structure 40, so that the second passivation layer 4 can cover part of the surface of the first passivation layer 2 which is not parallel to the substrate 1, and then the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1, thereby preventing the metal wires 30 respectively connected to the two pads of the micro LED from being connected, thereby improving the reliability of the product.

[0083] See also Fig.12 , illustratively, the orthographic projection of the first groove 22 on the substrate 1 can be located between the orthographic projection of the first metal wire 31 on the substrate 1 and the orthographic projection of the second metal wire 32 on the substrate 1. By setting the first groove 22 between two adjacent metal wires 30, the step structures 40 corresponding to the two adjacent metal wires 30 pass through the same first groove 22, so that the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1, effectively preventing the metal wires 30 connected to the two pads of the micro LED from being connected, thereby improving product reliability.

[0084] See also Fig.13 For example, the orthographic projection of the first groove 22 on the base substrate 1 can be spaced apart from the orthographic projection of the metal wire 30 on the base substrate 1. By staggering the edge of the first groove 22 and the edge of the metal wire 30, the step structure 40 includes at least two steps, thereby effectively preventing the metal wires 30 connected to the two pads of the micro LED from being connected, further improving product reliability.

[0085] See also Fig.14 In some embodiments, the light-emitting substrate may further include a planar layer 5 , and the planar layer 5 is located between the first passivation layer 2 and the base substrate 1 .

[0086] Exemplarily, in a direction perpendicular to the base substrate 1 , the thickness of the planarization layer 5 may be greater than the thickness of the first passivation layer 2 .

[0087] See also Fig.14 In a possible embodiment, when the first passivation layer 2 has at least one first opening 21, the planarization layer 5 may have at least one second opening 51, and the second opening 51 corresponds to the first opening 21. The orthographic projection of the second opening 51 on the base substrate 1 covers the orthographic projection of the corresponding first opening 21 on the base substrate 1. The first passivation layer 2 is partially located in the second opening 51.

[0088] In the above embodiment, by setting the second opening 51 at the position of the flat layer 5 corresponding to the first opening 21, at least a part of the first passivation layer 2 can be accommodated, so that the first passivation layer 2 forms a step structure, and the difficulty of the metal wire 30 migrating along the surface of the first passivation layer 2 that is not parallel to the base substrate 1 is increased, and a migration channel cannot be formed between two adjacent metal wires 30, thereby reducing the risk of micro LED short circuit and improving product reliability.

[0089] See also Fig.14 Exemplarily, the orthographic projection edge of the second opening 51 on the substrate 1 does not overlap with the orthographic projection edge of the corresponding first opening 21 on the substrate 1 . The second passivation layer 4 is partially located in the second opening 51 .

[0090] See also Fig.14 , illustratively, the orthographic projection of the second opening 51 on the substrate 1 can be located between the orthographic projection of the first metal wire 31 on the substrate 1 and the orthographic projection of the second metal wire 32 on the substrate 1. By setting the second opening 51 between two adjacent metal wires 30, the step structures 40 corresponding to the two adjacent metal wires 30 pass through the same second opening 51, so that the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1, and the first passivation layer 2 between the two adjacent metal wires 30 is formed with a step structure, which can effectively prevent the metal wires 30 connected to the two pads of the micro LED from being connected, thereby improving product reliability.

[0091] See also Fig.14, exemplarily, the flat layer 5 may include at least two flat sub-layers 50 stacked in sequence in a direction away from the base substrate 1. Each flat sub-layer 50 has a sub-opening corresponding to the second opening 51, and the sub-openings of each flat sub-layer 50 are connected one by one to form the corresponding second opening 51. By forming the flat layer 5 with at least two flat sub-layers 50, the thickness of the flat layer 5 can be increased, and then the depth of the second opening 51 can be increased, so that the distance between the plane where the surface of the second passivation layer 4 closest to the base substrate 1 is located and the plane where the surface of the metal layer 3 close to the base substrate 1 is located is increased, the difficulty of forming a migration channel between two adjacent metal wires 30 is increased, the risk of short circuit of the micro LED is reduced, and the product reliability is improved.

[0092] See also Fig.15 For example, the orthographic projection of the second opening 51 on the substrate 1 can be spaced apart from the orthographic projection of the metal wire 30 on the substrate 1. This is conducive to the step structure 40 forming multiple steps, greatly increasing the difficulty of migration of the metal wire 30, so that two adjacent metal wires 30 cannot form a migration channel and communicate with each other, effectively reducing the risk of short circuit of the micro LED and further improving the reliability of the product.

[0093] See also Fig.16 In another possible embodiment, when the first passivation layer 2 has at least one first groove 22, the planar layer 5 may have at least one second opening 51, and the second opening 51 corresponds to the first groove 22. The orthographic projection of the second opening 51 on the base substrate 1 covers the orthographic projection of the corresponding first groove 22 on the base substrate 1. The first passivation layer 2 is partially located in the second opening 51.

[0094] See also Fig.16 , illustratively, the orthographic projection edge of the second opening 51 on the base substrate 1 does not overlap with the orthographic projection edge of the corresponding first groove 22 on the base substrate 1. The second passivation layer 4 may be partially located in the second opening 51. By providing the second opening 51 at the position of the flat layer 5 corresponding to the first opening 21, the first passivation layer 2 covering the flat layer 5 can naturally form the first groove 22.

[0095] See also Fig.16 Exemplarily, the orthographic projection of the second opening 51 on the base substrate 1 may be located between the orthographic projection of the first metal line 31 on the base substrate 1 and the orthographic projection of the second metal line 32 on the base substrate 1 .

[0096] See also Fig.16For example, the planar layer 5 may include at least two planar sub-layers 50 stacked in sequence in a direction away from the base substrate 1. Each planar sub-layer 50 has a sub-opening corresponding to the second opening 51 one by one, and the sub-openings of each planar sub-layer 50 are connected one by one to form a corresponding second opening 51.

[0097] See also Fig.17 For example, the orthographic projection of the second opening 51 on the substrate 1 can be spaced apart from the orthographic projection of the metal wire 30 on the substrate 1. This is conducive to the step structure 40 forming multiple steps, greatly increasing the difficulty of migration of the metal wire 30, so that two adjacent metal wires 30 cannot form a migration channel and communicate with each other, effectively reducing the risk of short circuit of the micro LED and further improving the reliability of the product.

[0098] See also Fig.18 In another possible embodiment, when the first passivation layer 2 has at least one first opening 21, the planar layer 5 may have at least one second groove 52 recessed toward the base substrate 1, and the second groove 52 corresponds to the first opening 21. The orthographic projection of the second groove 52 on the base substrate 1 covers the orthographic projection of the corresponding first opening 21 on the base substrate 1. The first passivation layer 2 is partially located in the second groove 52.

[0099] In the above embodiment, by setting the second groove 52 at the position of the flat layer 5 corresponding to the first opening 21, at least a part of the first passivation layer 2 can be accommodated, so that the first passivation layer 2 forms a step structure, and the difficulty of the metal wire 30 migrating along the surface of the first passivation layer 2 that is not parallel to the base substrate 1 is increased, and a migration channel cannot be formed between two adjacent metal wires 30, thereby reducing the risk of micro LED short circuit and improving product reliability.

[0100] See also Fig.18 Exemplarily, the orthographic projection edge of the second groove 52 on the substrate 1 does not overlap with the orthographic projection edge of the corresponding first opening 21 on the substrate 1 . The second passivation layer 4 is partially located in the second opening 51 .

[0101] See also Fig.18, illustratively, the orthographic projection of the second groove 52 on the substrate 1 can be located between the orthographic projection of the first metal wire 31 on the substrate 1 and the orthographic projection of the second metal wire 32 on the substrate 1. By setting the second groove 52 between two adjacent metal wires 30, the step structures 40 corresponding to the two adjacent metal wires 30 pass through the same second groove 52, so that the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located is located between the surface of the metal layer 3 close to the substrate 1 and the substrate 1, and the first passivation layer 2 between the two adjacent metal wires 30 is formed with a step structure, which can effectively prevent the metal wires 30 connected to the two pads of the micro LED from being connected, thereby improving product reliability.

[0102] See also Fig.19 For example, the orthographic projection of the second groove 52 on the base substrate 1 can be spaced apart from the orthographic projection of the metal wire 30 on the base substrate 1. This is conducive to the step structure 40 forming multiple steps, greatly increasing the difficulty of migration of the metal wire 30, so that two adjacent metal wires 30 cannot form a migration channel and communicate with each other, effectively reducing the risk of short circuit of the micro LED and further improving the reliability of the product.

[0103] See also Fig. 20 In another possible embodiment, when the first passivation layer 2 has at least one first groove 22, the planar layer 5 may have at least one second groove 52 recessed toward the base substrate 1, and the second groove 52 corresponds to the first groove 22. The orthographic projection of the second groove 52 on the base substrate 1 covers the orthographic projection of the corresponding first groove 22 on the base substrate 1. The first passivation layer 2 is partially located in the second groove 52.

[0104] In the above embodiment, by providing the second groove 52 at the position of the planar layer 5 corresponding to the first opening 21 , the first passivation layer 2 covering the planar layer 5 can naturally form the first groove 22 .

[0105] See also Fig. 20 For example, the orthographic projection edge of the second groove 52 on the substrate 1 does not overlap with the orthographic projection edge of the corresponding first groove 22 on the substrate 1 . The second passivation layer 4 may be partially located in the second groove 52 .

[0106] See also Fig. 20 Exemplarily, the orthographic projection of the second groove 52 on the substrate 1 may be located between the orthographic projection of the first metal line 31 on the substrate 1 and the orthographic projection of the second metal line 32 on the substrate 1 .

[0107] See also Fig.21For example, the orthographic projection of the second groove 52 on the base substrate 1 can be spaced apart from the orthographic projection of the metal wire 30 on the base substrate 1. This is conducive to the step structure 40 forming multiple steps, greatly increasing the difficulty of migration of the metal wire 30, so that two adjacent metal wires 30 cannot form a migration channel and communicate with each other, effectively reducing the risk of short circuit of the micro LED and further improving the reliability of the product.

[0108] It should be noted that Figure 11-Figure 21 Take the example that the tread 401 of the first step structure 41 closest to the substrate 1 is connected to the tread 401 of the second step structure 42 closest to the substrate 1. The tread 401 of the first step structure 41 closest to the substrate 1 may also be disconnected from the tread 401 of the second step structure 42 closest to the substrate 1.

[0109] See also Fig. 22 In some embodiments, the light-emitting substrate may further include a third passivation layer 6 , and the third passivation layer 6 is located between the planar layer 5 and the base substrate 1 .

[0110] See also Fig.23 In a possible embodiment, when the planar layer 5 has at least one second opening 51, the third passivation layer 6 may have at least one third opening 61, and the third opening 61 corresponds to the second opening 51. The orthographic projection of the third opening 61 on the substrate 1 is located within the orthographic projection of the corresponding second opening 51 on the substrate 1. The first passivation layer 2 and / or the second passivation layer 4 are partially located within the third opening 61.

[0111] In the above embodiment, by setting the third opening 61 at the position of the third passivation layer 61 corresponding to the second opening 51, at least a part of the first passivation layer 2 or the second passivation layer 4 can be accommodated, so that the distance between the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located and the plane where the surface of the metal layer 3 close to the substrate 1 is located is increased, and the difficulty of forming a migration channel between two adjacent metal wires 30 is increased, thereby reducing the risk of short circuit of the micro LED and improving product reliability.

[0112] It should be noted that Fig.23 Taking the example that the second passivation layer 4 is partially located in the third opening 61 , the first passivation layer 2 may be partially located in the third opening 61 , or both the first passivation layer 2 and the second passivation layer 4 may be partially located in the third opening 61 .

[0113] See also Fig.23 Exemplarily, the orthographic projection of the third opening 61 on the substrate 1 may be located between the orthographic projection of the first metal line 31 on the substrate 1 and the orthographic projection of the second metal line 32 on the substrate 1 .

[0114] See also Fig.23 For example, the orthographic projection edge of the third opening 61 on the substrate 1 can be spaced apart from the orthographic projection edge of the corresponding second opening 51 on the substrate 1, so that the first passivation layer 2 or the second passivation layer 4 forms a step structure, and the difficulty of the metal wire 30 migrating along the surface of the first passivation layer 2 that is not parallel to the substrate 1 increases, and a migration channel cannot be formed between two adjacent metal wires 30, thereby reducing the risk of short circuit of the micro LED and improving product reliability.

[0115] See also Fig.24 In another possible embodiment, when the planar layer 5 has at least one second opening 51, the third passivation layer 6 may have at least one third groove 62 recessed toward the base substrate 1, and the third groove 62 corresponds to the second opening 51. The orthographic projection of the third groove 62 on the base substrate 1 is located within the orthographic projection of the corresponding second opening 51 on the base substrate 1. The first passivation layer 2 and / or the second passivation layer 4 are partially located in the third groove 62.

[0116] In the above embodiment, by setting the third groove 62 at the position of the third passivation layer 61 corresponding to the second opening 51, at least a part of the first passivation layer 2 or the second passivation layer 4 can be accommodated, so that the distance between the plane where the surface of the second passivation layer 4 closest to the substrate 1 is located and the plane where the surface of the metal layer 3 close to the substrate 1 is located is increased, and the difficulty of forming a migration channel between two adjacent metal wires 30 is increased, thereby reducing the risk of short circuit of the micro LED and improving product reliability.

[0117] See also Fig.24 Exemplarily, the orthographic projection of the third groove 62 on the substrate substrate 1 may be located between the orthographic projection of the first metal wire 31 on the substrate substrate 1 and the orthographic projection of the second metal wire 32 on the substrate substrate 1 .

[0118] See also Fig.24 For example, the orthographic projection edge of the third groove 62 on the substrate 1 can be spaced apart from the orthographic projection edge of the corresponding second opening 51 on the substrate 1, so that the first passivation layer 2 or the second passivation layer 4 forms a step structure, and the difficulty of the metal wire 30 migrating along the surface of the first passivation layer 2 that is not parallel to the substrate 1 increases, and a migration channel cannot be formed between two adjacent metal wires 30, thereby reducing the risk of short circuit of the micro LED and improving product reliability.

[0119] In practical applications, the first opening 21 can be opened after the first passivation layer 2 is formed, the second opening 52 can be opened after the planarization layer 5 is formed, and the third opening 61 needs to be opened after the second opening 52 is opened to prevent the planarization layer 5 from filling the third opening 61 .

[0120] See also Figure 22 to Figure 24Exemplarily, the light-emitting substrate may further include a buffer layer 7 , and the buffer layer 7 is located between the third passivation layer 6 and the base substrate 1 .

[0121] See also Figure 22 to Figure 25 In some embodiments, the light-emitting substrate may further include a pad 8 , the second passivation layer 4 on the metal layer 3 has an opening, and the pad 8 is connected to the metal layer 3 through the opening of the second passivation layer 4 .

[0122] Exemplarily, the pad 8 corresponds to the metal wire 30 , and the pad 8 is located on a side of the corresponding metal wire 30 away from the substrate 1 and connected to the corresponding metal wire 30 .

[0123] See also Figure 22 to Figure 24 In some embodiments, the light-emitting substrate may further include a filling layer 9 , and the filling layer 9 is located on a side of the second passivation layer 4 away from the base substrate 1 .

[0124] In some embodiments, the light-emitting substrate may further include a plurality of light-emitting devices. One light-emitting device corresponds to two pads 8, and each light-emitting device is located on a side of the pad 8 away from the base substrate 1 and is connected to the corresponding pad 8. Exemplarily, the light-emitting device may be a Mini LED light-emitting chip.

[0125] A second aspect of the present application provides a backlight module, which includes the light-emitting substrate provided by any of the above embodiments.

[0126] A third aspect of the present application provides a display device, which includes a display panel and a backlight module provided in the above embodiment.

[0127] See also Fig.26 According to a third aspect of the present application, a method for manufacturing a light-emitting substrate is provided. The method comprises the following steps S101 to S104.

[0128] Step S101, providing a base substrate.

[0129] Step S102: forming a first passivation layer on the base substrate, wherein the first passivation layer has a first opening or a first groove.

[0130] Exemplarily, the first opening may be formed simultaneously with other openings in the first passivation layer, and the first groove may be formed simultaneously with other grooves in the first passivation layer, without adding additional process steps.

[0131] Step S103: forming a metal layer on the first passivation layer.

[0132] The orthographic projection of the metal layer on the base substrate does not overlap with the orthographic projection of the first opening or the first groove on the base substrate.

[0133] Step S104: forming a second passivation layer on the metal layer and in the first opening or the first groove.

[0134] The second passivation layer at least covers a portion of the surface of the metal layer away from the substrate, a surface of the metal layer not parallel to the substrate, and a portion of the surface of the first passivation layer not parallel to the substrate. The surface of the second passivation layer closest to the substrate is located between the surface of the metal layer close to the substrate and the substrate.

[0135] See also Fig. 27 In some embodiments, before step S102, the manufacturing method may further include the following steps S201 to S202.

[0136] Step S201, forming a planar layer on a base substrate.

[0137] Step S202: etching the planar layer to form a second opening or a second groove.

[0138] The second opening corresponds to the first opening or the first groove, and the orthographic projection of the second opening on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate. The second groove corresponds to the first opening or the first groove, and the orthographic projection of the second groove on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate.

[0139] Accordingly, in step S102 , a first passivation layer is formed on the planar layer and in the second opening or the second groove.

[0140] Exemplarily, the second opening may be formed simultaneously with other openings in the planar layer, and the second groove may be formed simultaneously with other grooves in the planar layer, without adding additional process steps.

[0141] In some embodiments, before step S201, the manufacturing method may further include the following step: forming a third buffer layer on the base substrate.

[0142] Accordingly, in step S201 , a planarization layer is formed on the third passivation layer.

[0143] Exemplarily, when the planar layer is formed with a second opening, after the planar layer is formed on the third passivation layer, the manufacturing method may further include the following step: etching the third passivation layer to form a third opening or a third groove.

[0144] The third opening corresponds to the second opening, and the orthographic projection of the third opening on the substrate is located within the orthographic projection of the corresponding second opening on the substrate. The third groove corresponds to the second opening, and the orthographic projection of the third groove on the substrate is located within the orthographic projection of the corresponding second opening on the substrate.

[0145] Exemplarily, before forming the planar layer on the third passivation layer, the manufacturing method may further include the following step: forming a buffer layer on the base substrate.

[0146] Accordingly, a third passivation layer is formed on the buffer layer.

[0147] In some embodiments, after step S104, the manufacturing method further includes the following steps S301 to S303.

[0148] Step S301: forming an opening in a second passivation layer on the metal layer.

[0149] Step S302: forming a pad in the opening.

[0150] Step S303: forming a filling layer on the second passivation layer.

[0151] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0152] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0153] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0154] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0155] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A light-emitting substrate, characterized in that: The light-emitting substrate comprises: A substrate base plate (1); A first passivation layer (2) is located on the substrate (1); A metal layer (3) located on a side of the first passivation layer (2) away from the substrate (1); The second passivation layer (4) at least covers a portion of the surface of the metal layer (3) away from the substrate (1), a surface of the metal layer (3) not parallel to the substrate (1), and a portion of the surface of the first passivation layer (2) not parallel to the substrate (1); the plane where the surface of the second passivation layer (4) closest to the substrate (1) is located is located between the surface of the metal layer (3) close to the substrate (1) and the substrate (1).

2. The light-emitting substrate according to claim 1, characterized in that: The second passivation layer (4) comprises a step structure (40), wherein a surface of the step structure (40) close to the substrate (1) comprises at least two treads (401) and at least one riser (402), the treads (401) and the risers (402) are alternately connected, and the treads (401) are parallel to the substrate (1); The tread (401) of the step structure (40) which is farthest from the substrate (1) contacts a portion of the surface of the metal layer (3) away from the substrate (1); the riser (402) contacts a surface of the metal layer (3) which is not parallel to the substrate (1) and a surface of the first passivation layer (2) which is not parallel to the substrate (1); and the plane where the tread (401) of the step structure (40) which is closest to the substrate (1) is located is located between the surface of the metal layer (3) close to the substrate (1) and the substrate (1).

3. The light-emitting substrate according to claim 2, characterized in that: The metal layer (3) comprises at least two metal wires (30) arranged at intervals; the second passivation layer (4) comprises at least two step structures (40), each of the step structures (40) corresponding to one of the metal wires (30); The surface of the step structure (40) close to the substrate (1) contacts the surface of the corresponding metal wire (30); and the plane where the tread (401) of the step structure (40) closest to the substrate (1) is located is located between the surface of the corresponding metal wire (30) close to the substrate (1) and the substrate (1).

4. The light-emitting substrate according to claim 3, characterized in that: The first passivation layer (2) has at least one first opening (21); an orthographic projection of the first opening (21) on the substrate (1) does not overlap with an orthographic projection of the metal line (30) on the substrate (1); and a portion of the step structure (40) is located within the first opening (21); or, The first passivation layer (2) has at least one first groove (22) recessed toward the base substrate (1); an orthographic projection of the first groove (22) on the base substrate (1) does not overlap with an orthographic projection of the metal line (30) on the base substrate (1); and a portion of the step structure (40) is located within the first groove (22).

5. The light-emitting substrate according to claim 4, characterized in that: The step structure (40) includes at least two steps.

6. The light-emitting substrate according to claim 5, characterized in that: An orthographic projection of the first opening (21) or the first groove (22) on the base substrate (1) and an orthographic projection of the metal line (30) on the base substrate (1) are spaced apart from each other.

7. The light-emitting substrate according to any one of claims 4 to 6, characterized in that: The light-emitting substrate further comprises: A planar layer (5) located between the first passivation layer (2) and the substrate (1); The flat layer (5) has at least one second opening (51), the second opening (51) corresponds to the first opening (21) or the first groove (22); the orthographic projection of the second opening (51) on the substrate (1) covers the orthographic projection of the corresponding first opening (21) or the first groove (22) on the substrate (1); the first passivation layer (2) is partially located in the second opening (51); or, The flat layer (5) has at least one second groove (52) recessed toward the base substrate (1), the second groove (52) corresponding to the first opening (21) or the first groove (22); the orthographic projection of the second groove (52) on the base substrate (1) covers the orthographic projection of the corresponding first opening (21) or the first groove (22) on the base substrate (1); and the first passivation layer (2) is partially located in the second groove (52).

8. The light-emitting substrate according to claim 7, characterized in that: The orthographic projection of the second opening (51) or the second groove (52) on the base substrate (1) does not overlap with the orthographic projection of the metal wire (30) on the base substrate (1).

9. The light-emitting substrate according to claim 7, characterized in that: The flat layer (5) comprises at least two flat sub-layers (50) stacked in sequence in a direction away from the base substrate (1); each of the flat sub-layers (50) has a sub-opening corresponding to the second opening (51) one by one, and the sub-openings of the flat sub-layers (50) are connected one by one to form a corresponding second opening (51).

10. The light emitting substrate according to claim 7, characterized in that: The light-emitting substrate further comprises: A third passivation layer (6) is located between the flat layer (5) and the substrate (1); The third passivation layer (6) has at least one third opening (61), and the third opening (61) corresponds to the second opening (51); the orthographic projection of the third opening (61) on the substrate (1) is located within the orthographic projection of the corresponding second opening (51) on the substrate (1); the first passivation layer (2) and / or the second passivation layer (4) are partially located within the third opening (61); or, The third passivation layer (6) has at least one third groove (62) recessed toward the base substrate (1), and the third groove (62) corresponds to the second opening (51); an orthographic projection of the third groove (62) on the base substrate (1) is located within an orthographic projection of the corresponding second opening (51) on the base substrate (1); and a portion of the first passivation layer (2) and / or the second passivation layer (4) is located within the third groove (62).

11. The light emitting substrate according to claim 10, characterized in that: An orthographic projection edge of the third opening (61) or the third groove (62) on the base substrate (1) is spaced from an orthographic projection of the corresponding second opening (51) on the base substrate (1).

12. The light-emitting substrate according to any one of claims 4 to 6, characterized in that: At least two of the step structures (40) include a first step structure (41) and a second step structure (42); the metal wire (30) corresponding to the first step structure (41) is a first metal wire (31); the metal wire (30) corresponding to the second step structure (42) is a second metal wire (32); the first metal wire (31) and the second metal wire (32) are two adjacent metal wires (30) among the at least two metal wires (30); The orthographic projection of the first opening (21) or the first groove (22) on the substrate (1) is at least located between the orthographic projection of the first metal wire (31) on the substrate (1) and the orthographic projection of the second metal wire (32) on the substrate (1); the riser (402) of the first step structure (41) contacts the surface of the first metal wire (31) close to the second metal wire (32); and the riser (402) of the second step structure (42) contacts the surface of the second metal wire (32) close to the first metal wire (31).

13. The light emitting substrate according to claim 12, characterized in that: The tread (401) of the first step structure (41) that is closest to the substrate (1) is connected to the tread (401) of the second step structure (42) that is closest to the substrate (1).

14. The light emitting substrate according to claim 12, characterized in that: The first metal wire (31) is close to the surface of the substrate (1) and is located in the same plane parallel to the substrate (1) as the second metal wire (32) is close to the surface of the substrate (1); the first step structure (41) and the second step structure (42) are mirror-symmetrical relative to a reference plane perpendicular to the substrate (1).

15. A backlight module, characterized in that: The backlight module comprises the light-emitting substrate as described in any one of claims 1-14.

16. A display device, characterized in that: The display device comprises a display panel and the backlight module as claimed in claim 15 .

17. A method for manufacturing a light-emitting substrate, characterized in that: The production method comprises: Providing a substrate; forming a first passivation layer on the base substrate, wherein the first passivation layer has a first opening or a first groove; forming a metal layer on the first passivation layer; wherein an orthographic projection of the metal layer on the base substrate does not overlap with an orthographic projection of the first opening or the first groove on the base substrate; A second passivation layer is formed on the metal layer and in the first opening or the first groove, wherein the second passivation layer at least covers a portion of the surface of the metal layer away from the substrate, a surface of the metal layer that is not parallel to the substrate, and a portion of the surface of the first passivation layer that is not parallel to the substrate; a surface of the second passivation layer that is closest to the substrate is located between a surface of the metal layer close to the substrate and the substrate.

18. The manufacturing method according to claim 17, characterized in that: Before forming the first passivation layer on the substrate, the manufacturing method further includes: forming a planar layer on the base substrate; The flat layer is etched to form a second opening or a second groove; the second opening corresponds to the first opening or the first groove, and the orthographic projection of the second opening on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate; the second groove corresponds to the first opening or the first groove, and the orthographic projection of the second groove on the substrate covers the orthographic projection of the corresponding first opening or the first groove on the substrate.

19. The manufacturing method according to claim 18, characterized in that: Before forming a planar layer on the substrate, the manufacturing method further includes: forming a third passivation layer on the base substrate; After etching the planar layer to form the second opening, the manufacturing method further includes: The third passivation layer is etched to form a third opening or a third groove; the third opening corresponds to the second opening, and the orthographic projection of the third opening on the substrate is located within the orthographic projection of the corresponding second opening on the substrate; the third groove corresponds to the second opening, and the orthographic projection of the third groove on the substrate is located within the orthographic projection of the corresponding second opening on the substrate.

Images