Display module and preparation method thereof

Abstract

The application discloses a display module and a preparation method thereof. The display module is provided with a barrier wall layer on the surface of a substrate, and the barrier wall layer comprises a plurality of barrier wall units arranged in an array. Each barrier wall unit comprises a ring-shaped closed sidewall, so that each barrier wall unit defines a rectangular accommodation area on the surface of the substrate. One accommodation area corresponds to one LED chip. In the length direction of the accommodation area, the length of the accommodation area is greater than the length of the LED chip and is not greater than 3 / 2 of the length of the LED chip. In the width direction of the accommodation area, the width of the accommodation area is greater than the width of the LED chip and is not greater than 3 / 2 of the width of the LED chip. Therefore, each LED chip can be limited by the barrier wall unit corresponding to the accommodation area, the inclination and position deviation of the LED chip are reduced, the collimation degree of the LED chip bonded to the substrate is improved, and the bonding precision of the LED chip and the substrate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light emitting diode, in particular to a display module and a preparation method thereof. BACKGROUND

[0002] With the development of LED (Light Emitting Diode) technology, the application of Mini / Micro LED is more and more widely. At present, in the manufacturing process of display module, it is usually necessary to transfer a large number of Mini / Micro LED to a substrate. Whether it is the most mature stamp transfer technology, the most popular laser transfer technology, or the potential electrostatic transfer technology, fluid transfer technology and electromagnetic force transfer technology, it is necessary to align and bond the LED chip and the substrate. Common bonding processes include metal bonding and anisotropic conductive film (ACF) bonding.

[0003] However, no matter which kind of mass transfer technology or bonding method, the bonding precision of the LED chip of the existing display module with the substrate is poor during the transfer process. Specifically, the LED chip is skewed, resulting in an incorrect light emitting angle, and the pad structure on the substrate is not aligned, resulting in chip short circuit and non-lighting phenomenon. SUMMARY

[0004] To solve the above technical problems, the embodiments of the present application provide a display module and a preparation method thereof to improve the bonding precision of the LED chip with the substrate during the transfer process.

[0005] To achieve the above purpose, the embodiments of the present application provide the following technical solutions:

[0006] A display module comprises:

[0007] a substrate;

[0008] a barrier wall layer located on the surface of the substrate, the barrier wall layer comprising a plurality of barrier wall units arranged in an array, each barrier wall unit comprising a ring-shaped closed sidewall, so that each barrier wall unit defines a rectangular accommodation area on the surface of the substrate;

[0009] and a plurality of LED chips bonded and connected with the substrate, each accommodation area corresponding to one LED chip;

[0010] In the first direction, the length of the accommodating region is greater than the length of the LED chip and is not greater than 3 / 2 of the length of the LED chip, and in the second direction, the width of the accommodating region is greater than the width of the LED chip and is not greater than 3 / 2 of the width of the LED chip, the first direction is parallel to the length direction of the accommodating region, and the second direction is parallel to the width direction of the accommodating region.

[0011] Optionally, in a plane parallel to the surface of the substrate, each sidewall of the barrier wall unit has a preset distance with the LED chip surrounded by the barrier wall unit, and the preset distance is not greater than 2 μm.

[0012] Optionally, in a direction perpendicular to the surface of the substrate, the height of each sidewall of the barrier wall unit is not less than 1 / 2 of the height of the LED chip surrounded by the barrier wall unit.

[0013] Optionally, each barrier wall unit comprises a first sidewall, a second sidewall, a third sidewall and a fourth sidewall connected in sequence, and the first sidewall and the third sidewall extend along the first direction, and the second sidewall and the fourth sidewall extend along the second direction.

[0014] A plurality of barrier wall units are arranged in sequence along the first direction to form a plurality of rows, and a plurality of barrier wall units are arranged in sequence along the second direction to form a plurality of columns.

[0015] For any row, the fourth sidewall of the i-th barrier wall unit and the second sidewall of the i+1-th barrier wall unit are the same sidewall, i is an integer not less than 1.

[0016] For any column, the third sidewall of the j-th barrier wall unit and the first sidewall of the j+1-th barrier wall unit are the same sidewall, j is an integer not less than 1.

[0017] Optionally, the display module further comprises:

[0018] a reflective layer, the reflective layer comprising a first reflective part and a second reflective part formed integrally, the first reflective part covering the surface of each sidewall of the barrier wall unit, and the second reflective part covering each accommodating region.

[0019] The LED chip is located on the side of the corresponding second reflective part of the accommodating region away from the substrate, and the corresponding second reflective part of each accommodating region has a through hole, so that the LED chip is bonded to the substrate through the through hole on the second reflective part.

[0020] Optionally, the reflective layer is an aluminum metal layer or a platinum metal layer.

[0021] Optionally, the reflective layer comprises N film layers arranged in sequence along the thickness direction of the reflective layer, wherein the k+1th film layer is farther away from the LED chip than the kth film layer, and the refractive index of the k+1th film layer is greater than the refractive index of the kth film layer, k is an integer not less than 1.

[0022] Optionally, the barrier wall layer is an inorganic thin film layer.

[0023] A preparation method of a display module, comprising:

[0024] providing a substrate;

[0025] forming a barrier wall layer on the surface of the substrate;

[0026] etching the barrier wall layer to form a plurality of arrayed barrier wall units, each of the barrier wall units comprising a ring-shaped closed sidewall, so that each of the barrier wall units defines a rectangular receiving area on the surface of the substrate;

[0027] forming a pad structure in each of the receiving areas;

[0028] transferring an LED chip to each of the receiving areas, so that the LED chip corresponding to each of the receiving areas is bonded to the substrate through the pad structure of the receiving area;

[0029] wherein in a first direction, the length of the receiving area is greater than the length of the LED chip and not greater than 3 / 2 of the length of the LED chip, and in a second direction, the width of the receiving area is greater than the width of the LED chip and not greater than 3 / 2 of the width of the LED chip, the first direction being parallel to the length direction of the receiving area, and the second direction being parallel to the width direction of the receiving area.

[0030] Optionally, before forming the pad structure in each of the receiving areas, the method further comprises:

[0031] forming a reflective layer comprising a first reflective part and a second reflective part formed integrally, the first reflective part covering the surface of the sidewall of each of the barrier wall units, and the second reflective part covering each of the receiving areas;

[0032] forming the pad structure in each of the receiving areas comprises:

[0033] forming a via hole on the second reflective part corresponding to each of the receiving areas;

[0034] forming the pad structure on the via hole on the second reflective part corresponding to each of the receiving areas, so that the pad structure is electrically connected to the substrate through the via hole on the second reflective part.

[0035] Compared with the prior art, the technical scheme has the following advantages:

[0036] The display module provided by the embodiment of the application has the following advantages:

[0037] In addition, the sidewall of the barrier wall unit 210 is arranged around each LED chip 300, and the arrangement of the barrier wall unit 210 can prevent light interference between the LED chips 300. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0039] Figure 1 FIG. 1 is a cross-sectional structure schematic diagram of a display module according to the prior art;

[0040] Figure 2 FIG. 2 is a cross-sectional structure schematic diagram of a display module according to an embodiment of the present application;

[0041] Figure 3 FIG. 3 is a partial top view schematic diagram of a display module according to an embodiment of the present application;

[0042] Figure 4 FIG. 4 is a top view schematic diagram of an area surrounded by a barrier wall unit in a display module according to an embodiment of the present application;

[0043] Figure 5 FIG. 5 is a cross-sectional structure schematic diagram of a display module according to another embodiment of the present application;

[0044] Figure 6 A light ray transmission diagram of the light emitted by the LED chip incident to the reflection layer including a plurality of film layers in the display module provided by an embodiment of the present application;

[0045] Figure 7 A light ray transmission diagram of the light incident vertically from one medium to another medium;

[0046] Figures 8(a)-8(f) A device structure diagram corresponding to each process step in the preparation method of the display module provided by an embodiment of the present application;

[0047] Figures 9(a)-9(c) A device structure diagram corresponding to each process step in the preparation method of the display module provided by another embodiment of the present application. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be described clearly and completely in the following description with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0049] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can be practiced without the specific details, which are different from the description, and the skilled in the art can make similar generalization without departing from the content of the present application, therefore, the present application is not limited to the specific embodiments disclosed below.

[0050] Secondly, the present application is described in detail in combination with the schematic diagram, and in the detailed description of the embodiments of the present application, the cross-sectional view of the device structure will be partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application herein. In addition, the three-dimensional spatial dimensions including length, width and depth should be included in the actual manufacture.

[0051] As described in the background section, no matter which kind of mass transfer technology, or which kind of bonding mode with the pad structure, the bonding accuracy of the LED chip of the existing display module with the substrate in the transfer process is poor.

[0052] Specifically, Figure 1 The cross-sectional structure diagram of the existing display module is given, from Figure 1It can be seen that in the process of transferring a plurality of LED chips 01 to the substrate substrate 02, the LED chip 01 is one-to-one aligned and bonded with the pad structure 03 on the substrate substrate 02. However, it is obvious that the LED chip 01 will be skewed, which will cause the light emitting angle of the LED chip to be incorrect, and the LED chip 01 will also be misaligned with the pad structure 03 on the substrate substrate 02, which will cause the LED chip to be short-circuited and not light up.

[0053] The inventor found that because the LED chip 01 needs to be welded with the pad structure 03 on the substrate substrate 02 in the process of transferring a large number of LED chips 01 to the substrate substrate 02, welding requires a certain temperature, and the LED chip 01 and the pad structure 03 will expand at the welding temperature, but the thermal expansion of different materials is different, which leads to poor collimation of the LED chip 01 bonded to the substrate substrate 02. The specific performance is that the LED chip 01 is skewed to cause the light emitting angle to be incorrect, and the pad structure 03 on the substrate substrate 02 is misaligned to cause the chip to be short-circuited and not light up, thereby causing the bonding precision of the LED chip to the substrate substrate to be poor during the transfer process, and finally the display module formed has a relatively low lighting yield of the LED chip, the overall repair cost is relatively high, and even the light emitting angle of each LED chip is different, which affects the final display effect.

[0054] At present, in order to improve the bonding precision of the LED chip to the substrate substrate during the transfer process, the time for aligning and bonding the LED chip and the pad structure on the substrate substrate is usually prolonged, but this will seriously affect the production efficiency.

[0055] In addition, the inventor also found that referring to FIG. 1, generally after a large number of LED chips 01 are transferred to the substrate substrate 02, a whole encapsulation glue layer 04 is covered, but the encapsulation glue layer 04 is usually an organic material layer, which has poor stability and is also not conducive to the precise bonding of the LED chip 01 and the substrate substrate 02. Even the encapsulation glue layer 04 cannot block the light interference between the LED chips. Figure 1

[0056] Therefore, the embodiment of the present application provides a display module, Figure 2 The cross-sectional schematic view of the display module provided by the embodiment of the present application is given, Figure 3 The partial top view schematic view of the display module provided by the embodiment of the present application is given, and it can be seen from the figure that the display module comprises:

[0057] a substrate substrate 100;

[0058] ​A barrier layer 200 is located on the surface of the substrate 100, and the barrier layer 200 includes a plurality of barrier units 210 arranged in an array, each barrier unit 210 including a ring-shaped closed sidewall, so that each barrier unit 210 defines a rectangular receiving area 110 on the surface of the substrate 100;

[0059] A plurality of LED chips 300 are bonded to the substrate 100, and each receiving area 110 corresponds to one LED chip, i.e., each receiving area 110 is used to carry one LED chip 300 bonded to the substrate 100;

[0060] As shown in Figure 4 , Figure 4 is a top view of the area surrounded by one barrier unit 210. As can be seen from the figure, in a first direction, the length of the receiving area 110 is greater than the length of the LED chip 300 and is not greater than 3 / 2 times the length of the LED chip 300, and in a second direction, the width of the receiving area 110 is greater than the width of the LED chip 300 and is not greater than 3 / 2 times the width of the LED chip 300, the first direction being parallel to the length direction of the receiving area 110, and the second direction being parallel to the width direction of the receiving area 110.

[0061] In the embodiment, since the sidewall of each barrier unit 210 defines a rectangular receiving area 110 on the surface of the substrate 100, in combination with Figure 3 and Figure 4 shown, the length of the receiving area 110 is the spacing of the sidewall of the barrier unit 210 in the length direction (i.e., the first direction) of the receiving area 110. The length of the receiving area 110 is set to X, i.e., the spacing of the sidewall of the barrier unit 210 in the length direction (i.e., the first direction) of the receiving area 110 is X, the length of the LED chip 300 in the length direction (i.e., the first direction) of the receiving area 110 is X1, then X1≤X≤3 / 2*X1.

[0062] Similarly, in combination with Figure 3 and Figure 4 shown, the width of the receiving area 110 is the spacing of the sidewall of the barrier unit 210 in the width direction (i.e., the second direction) of the receiving area 110. The width of the receiving area 110 is set to Y, i.e., the spacing of the sidewall of the barrier unit 210 in the width direction (i.e., the second direction) of the receiving area 110 is Y, the width of the LED chip 300 in the width direction (i.e., the second direction) of the receiving area 110 is Y1, then Y1≤Y≤3 / 2*Y1.

[0063] In this embodiment, in the first direction, the length of the receiving region 110 is greater than the length of the LED chip 300, so that the LED chip can be transferred to the receiving region 110. The length of the receiving region 110 is not greater than 3 / 2 of the length of the LED chip. Therefore, when the LED chip 300 is transferred to the receiving region 110, if the LED chip is tilted, the sidewall of the baffle unit 210 can support and limit the LED chip to avoid a large degree of tilt. If the LED chip is offset, since the sidewall of the baffle unit 210 limits the position of the receiving region 110, the LED chip can only be offset within the receiving region 110 at most to avoid excessive offset.

[0064] Similarly, in the second direction, the width of the receiving area 110 is greater than the width of the LED chip 300, so that the LED chip can be transferred to the receiving area 110. The width of the receiving area 110 is not greater than 3 / 2 of the width of the LED chip. Therefore, when the LED chip 300 is transferred to the receiving area 110, if the LED chip is tilted, the sidewall of the baffle unit 210 can support and limit the LED chip to avoid a large degree of tilt. If the LED chip is offset, since the sidewall of the baffle unit 210 limits the position of the receiving area 110, the LED chip can only be offset within the receiving area 110 at most to avoid excessive offset.

[0065] In this embodiment, the retaining wall layer 200 includes a plurality of retaining wall units 210 arranged in an array, wherein adjacent retaining wall units 210 may have a certain spacing or may be arranged closely together.

[0066] In this embodiment, the baffle units 210 can be arranged in rows. In each row, adjacent baffle units 210 can be closely connected. There can be a certain distance between rows, or they can be arranged closely. The baffle units 210 in two adjacent rows can be arranged in a one-to-one correspondence or staggered, depending on the situation. It can be understood that the row direction can be any direction parallel to the surface of the substrate 100.

[0067] In practical applications, combined with Figures 2-4 As shown, the LED chip 300 is typically bonded to the substrate 100 via a pad structure 400 disposed on the substrate 100. Specifically, the LED chip 300 typically includes an N electrode and a P electrode. The N electrode is bonded to the substrate 100 via a pad structure, and the P electrode is bonded to the substrate 100 via a pad structure.

[0068] In the embodiment, the LED chip 400 can include a red light LED chip, a green light LED chip and a blue light LED chip to combine red light emitted by the red light LED chip, green light emitted by the green light LED chip and blue light emitted by the blue light LED chip into white light. Of course, the LED chip 400 can also include an LED chip of one color, and can also include a combination of LED chips of two colors or more colors, which is not limited in the present application and is determined according to the situation.

[0069] It should be noted that the length of the accommodation area 110 can be greater than or equal to the width of the accommodation area 110, and when the length of the accommodation area 110 is equal to the width of the accommodation area 110, the accommodation area 110 is a square.

[0070] It should also be noted that since the accommodation area 110 is rectangular, the pattern surrounded by the inner wall of the side wall of the barrier wall unit 210 is rectangular, but the present application does not limit the pattern surrounded by the outer wall of the side wall of the barrier wall unit 210 to be any annular closed pattern, that is, the outer wall of the side wall of the barrier wall unit 210 can be surrounded by any annular closed pattern.

[0071] It should be noted that the present application does not limit the shape of the LED chip 300, that is, the shape of the LED chip 300 can be rectangular, circular or polygonal, etc.

[0072] Therefore, the display module provided by the embodiment of the present application sets the barrier wall layer on the surface of the substrate, and the barrier wall layer includes a plurality of barrier wall units arranged in an array, each barrier wall unit includes an annular closed side wall, so that each barrier wall unit defines a rectangular accommodation area on the surface of the substrate, each accommodation area is used to carry an LED chip transferred into the accommodation area, so that the LED chip is bonded and connected with the substrate in the accommodation area, wherein in the length direction of the accommodation area, the length of the accommodation area is greater than the length of the LED chip and not greater than 3 / 2 of the length of the LED chip, and in the width direction of the accommodation area, the width of the accommodation area is greater than the width of the LED chip and not greater than 3 / 2 of the width of the LED chip, so that each LED chip can be limited by the corresponding barrier wall unit of the accommodation area during the transfer to the corresponding accommodation area, reducing the skew and position deviation of the LED chip, improving the collimation of the LED chip bonded to the substrate, and improving the bonding accuracy of the LED chip with the substrate during the transfer process.

[0073] Moreover, the side wall of the barrier wall unit 210 is provided around each LED chip 300, that is, the barrier wall unit 210 is also provided to prevent light interference between the LED chips 300.

[0074] Further, in order to enhance the confining effect of the sidewall of the barrier wall unit 210 on the LED chip 300 surrounded by the barrier wall unit 210, in an embodiment of the present application, a preset distance is provided between the sidewall of each barrier wall unit 210 and the LED chip 300 surrounded by the barrier wall unit 210 in a plane parallel to the surface of the substrate 100, and the preset distance is not greater than 2 μm.

[0075] In the embodiment, as shown in FIG. 2, in a plane parallel to the surface of the substrate 100, the distance between the sidewall of the barrier wall unit 210 and the LED chip 300 surrounded by the barrier wall unit 210, specifically, the distance between the inner wall of the sidewall of the barrier wall unit 210 and the LED chip 300 surrounded by the barrier wall unit 210, is d1 in the first direction and d2 in the second direction, and d1 and d2 are both not greater than 2 μm. Figure 3 In the embodiment, in order to ensure that the LED chip 300 can be transferred into the accommodating region 110 surrounded by the barrier wall unit 210, a certain preset distance is required between the sidewall of the barrier wall unit 210 and the LED chip 300 surrounded by the barrier wall unit 210, and in order to ensure that the barrier wall unit 210 surrounding the accommodating region 110 can better confine the LED chip 300 during the transfer of the LED chip 400 into the accommodating region 110, the preset distance between the sidewall of each barrier wall unit 210 and the LED chip 300 surrounded by the barrier wall unit 210 is not greater than 2 μm, so that when the LED chip is tilted, the sidewall of the barrier wall unit 210 can confine and support the LED chip to avoid a large degree of tilting of the LED chip, and when the position of the LED chip is offset, since the barrier wall unit 210 confines the position of the accommodating region 110, the LED chip can be offset at most in the accommodating region 110 to avoid a large degree of offset of the LED chip.

[0076] On the basis of any of the above embodiments, in an embodiment of the present application, as shown in FIG. 3, in the direction perpendicular to the surface of the substrate 100, the height of the sidewall of each barrier wall unit 210 is not less than 1 / 2 of the height of the LED chip 300 surrounded by the barrier wall unit 210, so as to prevent the LED chip 300 from climbing over the sidewall of the barrier wall unit 210 due to tilting or position offset when the height of the sidewall of the barrier wall unit 210 is low.

[0077] Figure 2 On the basis of any of the above embodiments, in an embodiment of the present application, as shown in FIG. 3, in the direction perpendicular to the surface of the substrate 100, the height of the sidewall of each barrier wall unit 210 is not less than 1 / 2 of the height of the LED chip 300 surrounded by the barrier wall unit 210, so as to prevent the LED chip 300 from climbing over the sidewall of the barrier wall unit 210 due to tilting or position offset when the height of the sidewall of the barrier wall unit 210 is low.

[0078] ​It should be noted that, in this embodiment, in the direction perpendicular to the surface of the substrate 100, the height of the sidewall of the barrier unit 210 is the distance between the surface of the barrier unit 210 facing away from the substrate 100 and the surface of the substrate 100. Similarly, in the direction perpendicular to the surface of the substrate 100, the height of the LED chip 300 is the distance between the surface of the LED chip facing away from the substrate 100 and the surface of the substrate 100.

[0079] Specifically, in one embodiment of this application, reference is made to... Figure 2 As shown, in the direction perpendicular to the surface of the substrate 100, the height of the sidewall of each baffle unit 210 is not less than the height of the LED chip 400 surrounded by the baffle unit. That is, in the direction perpendicular to the surface of the substrate 100, the height of the sidewall of each baffle unit 210 is greater than or equal to the height of the LED chip 400 surrounded by the baffle unit, so as to enhance the limiting effect of the sidewall of the baffle unit 210 on the LED chip 300 surrounded by the baffle unit 210.

[0080] Based on any of the above embodiments, in one embodiment of this application, reference is made to... Figure 3 As shown, each retaining wall unit 210 includes a first sidewall 211, a second sidewall 212, a third sidewall 213 and a fourth sidewall 214 connected end to end in sequence, and the first sidewall 211 and the third sidewall 213 extend along a first direction, while the second sidewall 212 and the fourth sidewall 214 extend along a second direction.

[0081] Multiple retaining wall units 210 are arranged sequentially along the first direction to form multiple rows, and multiple retaining wall units 210 are arranged sequentially along the second direction to form multiple columns;

[0082] For any row, the fourth sidewall 214 of the i-th retaining wall unit 210 and the second sidewall 212 of the (i+1)-th retaining wall unit 210 are the same sidewall, where i is an integer not less than 1.

[0083] For any column, the third sidewall 213 of the j-th retaining wall unit 210 and the first sidewall 211 of the (j+1)-th retaining wall unit 210 are the same sidewall, where j is an integer not less than 1.

[0084] In this embodiment, the projection of each baffle unit 210 onto the surface of the substrate 100 is a rectangle, that is, the shape enclosed by the inner and outer walls of the sidewalls of each baffle unit 210 is a rectangle.

[0085] In this embodiment, each retaining wall unit 210 is arranged in a row in the first direction, and in each row, adjacent retaining wall units 210 share the same sidewall. They are also arranged in a column in the second direction, and in each column, adjacent retaining wall units 210 also share the same sidewall, so as to fully improve the space utilization of the display module.

[0086] In the above embodiments, the side wall of the barrier wall unit 210 is arranged around each LED chip 300, that is, the light emitted by the LED chip 300 is irradiated onto the side wall of the barrier wall unit 210. Therefore, in order to further improve the display brightness of the display module, in an embodiment of the present application, as shown in Figure 5 , the display module further comprises:

[0087] a reflective layer 500, the reflective layer 500 comprises a first reflective portion 510 and a second reflective portion 520 which are integrally formed, the first reflective portion 510 covers the surface of the side wall of each barrier wall unit 210, including the inner wall and the outer wall of the side wall of each barrier wall unit 210 and the surface away from the substrate 100, and the second reflective portion 520 covers each accommodating region 110;

[0088] The LED chip 300 is located on the side of the second reflective portion 520 corresponding to the accommodating region 110 away from the substrate 100, and the second reflective portion 520 corresponding to each accommodating region 110 has a through hole, so that the LED chip 300 is bonded to the substrate 100 through the through hole on the second reflective portion 520.

[0089] It should be noted that, since Figure 5 is a cross-sectional structure diagram of the display module, therefore, Figure 5 the through hole on the second reflective portion 520 is not drawn in .

[0090] In the embodiment, referring to Figure 5 , the light emitted from the LED chip 300 will be reflected by the first reflective portion 510 covering the surface of the side wall of the barrier wall unit 210 if the light is irradiated onto the side wall of the barrier wall unit 210, and the reflected light will be concentrated to the opposite position of the LED chip; if the light is irradiated onto the surface of the substrate 100, the light will be reflected by the second reflective portion 520 covering the accommodating region 100, and the reflected light is towards the light exit surface of the display module. Therefore, by arranging the reflective layer 500 covering the surface of the side wall of each barrier wall unit 210 and each accommodating region 110, the reflection of the light to the light exit surface of the display module is increased, and the display brightness and the light emitting efficiency of the display module are greatly improved.

[0091] On the basis of the above embodiments, in an embodiment of the present application, the reflective layer 500 is an aluminum metal layer or a platinum metal layer, so that the reflective layer 500 has a higher reflectivity.

[0092] Optionally, in another embodiment of the present application, in combination with Figure 5 and Figure 6As shown, the reflective layer 500 includes N film layers arranged in sequence along the thickness direction of the reflective layer 500, wherein the k+1th film layer is farther away from the LED chip than the kth film layer, and the k+1th film layer has a refractive index greater than that of the kth film layer, k being an integer not less than 1.

[0093] In this embodiment, the reflective layer 500 is made on the substrate 100 in combination with the sidewall of the barrier unit 210. Figure 5 and Figure 6 As shown, since the LED chip is located on the second reflective portion 520 in the reflective layer 500, in the second reflective portion 520, the k+1th film layer is farther away from the LED chip than the kth film layer, i.e., the k+1th film layer is closer to the substrate 100 than the kth film layer. In the first reflective portion 510, for example, for the portion of the first reflective portion 510 located on the inner wall of the barrier unit 210, the k+1th film layer is farther away from the LED chip than the kth film layer, i.e., the k+1th film layer is closer to the inner wall of the barrier unit 210 than the kth film layer.

[0094] That is, when the reflective layer 500 is made on the substrate 100, in the direction away from the substrate 100, the film layers in the reflective layer 500 are arranged from the Nth film layer to the 1st film layer, the 1st film layer is closest to the LED chip and has the smallest refractive index, and the Nth film layer is farthest away from the LED chip and has the largest refractive index. The film layers in the reflective layer 500 are deposited on the sidewall of the barrier unit 210 to form the first reflective portion 510 and on the accommodation region 110 to form the second reflective portion 520.

[0095] Figure 6 A schematic diagram of light transmission of light emitted by the LED chip incident on the reflective layer 500 including multiple film layers is given. As can be seen from the diagram, first, the reflective layer 500 includes N film layers arranged in sequence along the thickness direction of the reflective layer 500, so that light transmitted through the previous film layer is reflected at the interface between the previous film layer and the next film layer, for example, light transmitted through the 1st film layer is reflected at the interface between the 1st film layer and the 2nd film layer, and light transmitted through the 2nd film layer is reflected at the interface between the 2nd film layer and the 3rd film layer, i.e., the reflectivity of light transmitted into the reflective layer 500 is increased.

[0096] Secondly, the light emitted from the LED chip 300 towards the reflective layer 500 first strikes the surface of the first film layer of the reflective layer 500 facing the LED chip 300, where it is reflected and refracted. Next, the refracted light strikes the interface between the first and second film layers, where it is reflected and refracted again. Since the refractive index of the second film layer is greater than that of the first film layer, it's equivalent to the light moving from a less dense medium to a denser medium, and the angle of refraction decreases relative to the angle of incidence. Then, the refracted light strikes the interface between the second and third film layers, where it is reflected and refracted again. Again, since the refractive index of the third film layer is greater than that of the second film layer, it's equivalent to the light moving from a less dense medium to a denser medium, and the angle of refraction decreases again relative to the angle of incidence. Therefore, as the refracted light continues to strike the interfaces of adjacent film layers, the angle of refraction decreases further. We know that, as... Figure 7 As shown, when light is incident perpendicularly from one medium to another, only reflected light is produced, and no refracted light is produced. Therefore, in this embodiment, as light is incident on the film layer of the reflective layer 500 that is far away from the LED chip 300, the angle of incidence becomes smaller and smaller, and the angle of refraction also becomes smaller and smaller. When the angle of refraction is small enough, it will approximate the case of perpendicular incidence. At this time, there is more reflected light and the refracted light can be almost ignored, thereby further increasing the reflectivity of the light transmitted into the interior of the reflective layer 500.

[0097] It should be noted that, Figure 6 The example shown is based on a reflective layer 500 comprising three film layers. This application does not limit the specific number of film layers included in the reflective layer 500. For example, the reflective layer 500 may include two film layers or more than three film layers, depending on the specific circumstances.

[0098] It should also be noted that each film layer in the reflective layer 500 can be an inorganic thin film layer, which can be a silicon dioxide layer, a titanium dioxide layer, an aluminum oxide layer, a silicon nitride layer, or an aluminum nitride layer.

[0099] Therefore, the display module provided in this application embodiment increases the reflectivity of light transmitted into the interior of the reflective layer by setting a reflective layer comprising N film layers arranged sequentially along its thickness direction, and the film layer further away from the LED has a larger refractive index, thereby greatly improving the display brightness and luminous efficiency of the display module.

[0100] Based on any of the above embodiments, in one embodiment of this application, the barrier layer 200 can be an inorganic thin film layer, which has better mechanical stability than organic material layers. Specifically, the inorganic thin film layer can be a silicon dioxide layer, a titanium dioxide layer, an aluminum oxide layer, a silicon nitride layer, or an aluminum nitride layer.

[0101] It should be noted that in actual application, as shown in Figure 2 The display module provided by the embodiment of the present application further includes a sealing layer 600, which fills each barrier wall unit 210 to seal and protect the LED chip 300 surrounded by the sidewall of the barrier wall unit 210.

[0102] The embodiment of the present application further provides a preparation method of a display module, which includes the following steps:

[0103] S100: as shown in FIG. 8(a), a substrate 100 is provided.

[0104] Optionally, the substrate 100 can be a PCB substrate, a glass substrate, a flexible substrate, etc., which is determined according to the actual situation.

[0105] S200: as shown in FIG. 8(b), a barrier wall layer 200 is formed on the surface of the substrate 100.

[0106] Specifically, an inorganic thin film layer can be formed on the surface of the substrate 100 by thin film evaporation of inorganic matter, and the inorganic thin film layer is used as the barrier wall layer 200. The inorganic thin film layer can be a silicon dioxide layer, a titanium dioxide layer, an aluminum oxide layer, a silicon nitride layer or an aluminum nitride layer.

[0107] S300: as shown in FIG. 8(c), the barrier wall layer 200 is etched to form a plurality of barrier wall units 210 arranged in an array, and as shown in Figure 3 Each barrier wall unit 210 includes a ring-shaped closed sidewall, so that each barrier wall unit 210 defines a rectangular accommodation area 110 on the surface of the substrate 100.

[0108] Specifically, the barrier wall layer 200 can be etched to form a plurality of barrier wall units 210 by using a dry etching process or a wet etching process.

[0109] S400: as shown in FIG. 8(d), a pad structure 400 is formed in each accommodation area 110.

[0110] Specifically, the pad structure 400 can be formed in each accommodation area 110 by using a process such as electroplating, chemical plating, electron beam evaporation, thermal evaporation, etc. The material of the pad structure 400 includes low-melting-point metals such as gold, tin, tin alloy and indium.

[0111] S500: as shown in FIG. 8(e), an LED chip 300 is transferred to each accommodation area 110, so that the LED chip 300 corresponding to each accommodation area 110 is bonded and connected to the substrate 100 through the pad structure 400 of the accommodation area 110;

[0112] Specifically, a stamp transfer process or a laser transfer process can be used to transfer the LED chip 300 to each accommodating area 110, so that it is bonded to the substrate 100 through the pad structure 400.

[0113] Among them, combined Figure 4 As shown, in the first direction, the length X of the accommodating region 110 is greater than the length X1 of the LED chip, but not greater than 3 / 2 of the length X1 of the LED chip, i.e., X1≤X≤3 / 2*X1. In the second direction, the width Y of the accommodating region is greater than the width Y1 of the LED chip, but not greater than 3 / 2 of the width Y1 of the LED chip, i.e., Y1≤Y≤3 / 2*Y1. The first direction is parallel to the length direction of the accommodating region 110, and the second direction is parallel to the width direction of the accommodating region 110.

[0114] In this embodiment, the LED chip 400 may include a red LED chip, a green LED chip, and a blue LED chip, so that the red light emitted by the red LED chip, the green light emitted by the green LED chip, and the blue light emitted by the blue LED chip are combined to form white light. Of course, the LED chip 400 may also include LED chips of one color, or a combination of LED chips of two or more colors. This application does not limit this, and it depends on the specific circumstances.

[0115] In this embodiment, the LED chip 300 is bonded to the substrate 100 via a pad structure 400 disposed on the substrate 100. Specifically, the LED chip 300 typically includes an N electrode and a P electrode. The N electrode is bonded to the substrate 100 via a pad structure, and the P electrode is bonded to the substrate 100 via a pad structure.

[0116] The manufacturing method of the display module provided in the embodiments of the present application comprises the following steps: a substrate is provided; a barrier wall layer is arranged on the surface of the substrate, and the barrier wall layer comprises a plurality of barrier wall units arranged in an array, each barrier wall unit comprises a ring-shaped closed sidewall, so that each barrier wall unit defines a rectangular accommodating area on the surface of the substrate, each accommodating area is used for carrying an LED chip transferred into the accommodating area, and the LED chip is bonded to the substrate in the accommodating area, wherein, in the length direction of the accommodating area, the length of the accommodating area is greater than the length of the LED chip and is not greater than 3 / 2 of the length of the LED chip, and in the width direction of the accommodating area, the width of the accommodating area is greater than the width of the LED chip and is not greater than 3 / 2 of the width of the LED chip, so that each LED chip can be limited by the corresponding barrier wall unit of the accommodating area in the process of being transferred into the corresponding accommodating area, the inclination and position deviation of the LED chip are reduced, the alignment of the LED chip bonded to the substrate is improved, and the bonding accuracy of the LED chip to the substrate in the transfer process is improved. In addition, the sidewall of the barrier wall unit 210 is arranged around each LED chip 300, that is, the barrier wall unit 210 is arranged, which can also prevent light interference between the LED chips 300.

[0117] In actual application, the manufacturing method further comprises the following steps:

[0118] S600: as shown in FIG. 8(f), a sealing layer 600 is formed, the sealing layer 600 fills each barrier wall unit 210, so as to seal and protect the LED chip 300 surrounded by the sidewall of the barrier wall unit 210.

[0119] Further, in order to enhance the limiting effect of the sidewall of the barrier wall unit 210 on the LED chip 300 surrounded by the barrier wall unit 210, optionally, in an embodiment of the present application, as shown in FIG. 8(a), in the plane parallel to the surface of the substrate 100, each sidewall of the barrier wall unit 210 has a preset distance from the LED chip 300 surrounded by the barrier wall unit 210, and the preset distance is not greater than 2 μm. Figure 3

[0120] On the basis of any of the above embodiments, optionally, in an embodiment of the present application, in the direction perpendicular to the surface of the substrate 100, the height of the sidewall of each barrier wall unit 210 is not less than 1 / 2 of the height of the LED chip 300 surrounded by the barrier wall unit 210, so as to prevent the LED chip 300 from climbing over the sidewall of the barrier wall unit 210 due to inclination or position deviation when the height of the sidewall of the barrier wall unit 210 is low.

[0121] Specifically, in an embodiment of the present application, as shown in FIG. 8(a), in the plane parallel to the surface of the substrate 100, each sidewall of the barrier wall unit 210 has a preset distance from the LED chip 300 surrounded by the barrier wall unit 210, and the preset distance is not greater than 2 μm. Figure 3 ​As shown, each retaining wall unit 210 includes a first sidewall 211, a second sidewall 212, a third sidewall 213 and a fourth sidewall 214 connected end to end in sequence, and the first sidewall 211 and the third sidewall 213 extend along a first direction, while the second sidewall 212 and the fourth sidewall 214 extend along a second direction.

[0122] Multiple retaining wall units 210 are arranged sequentially along the first direction to form multiple rows, and multiple retaining wall units 210 are arranged sequentially along the second direction to form multiple columns;

[0123] For any row, the fourth sidewall 214 of the i-th retaining wall unit 210 and the second sidewall 212 of the (i+1)-th retaining wall unit 210 are the same sidewall, where i is an integer not less than 1.

[0124] For any column, the third sidewall 213 of the j-th retaining wall unit 210 and the first sidewall 211 of the (j+1)-th retaining wall unit 210 are the same sidewall, where j is an integer not less than 1.

[0125] In this embodiment, the projection of each baffle unit 210 onto the surface of the substrate 100 is rectangular, that is, the inner and outer walls of the sidewalls of each baffle unit 210 are both rectangular.

[0126] In this embodiment, each retaining wall unit 210 is arranged in a row in the first direction, and in each row, adjacent retaining wall units 210 share the same sidewall. They are also arranged in a column in the second direction, and in each column, adjacent retaining wall units 210 also share the same sidewall, so as to fully improve the space utilization rate.

[0127] In the above embodiments, sidewalls of baffle units 210 are provided around each LED chip 300, meaning that the light emitted by the LED chip will illuminate the sidewalls of the baffle units 210. Based on this, in order to further improve the display brightness of the display module, optionally, in one embodiment of this application, before the pad structure 400 is formed in each accommodating area 110, i.e., based on the device structure shown in FIG8(c), the method further includes:

[0128] S700: As shown in FIG9(a), a reflective layer 500 is formed. The reflective layer 500 includes an integrally formed first reflective portion 510 and a second reflective portion 520. The first reflective portion 510 covers the surface of the sidewall of each retaining wall unit 210, and the second reflective portion 520 covers each accommodating area 110.

[0129] Specifically, a reflective layer 500 is deposited on the side wall of the retaining wall unit 210 and on the accommodating area 110. The thickness of the reflective layer 500 can be 10nm-5μm.

[0130] In step S400, as shown in FIG9(b), forming a pad structure 400 in each accommodating region 110 includes:

[0131] S410: A through hole is formed on the second reflective portion 520 corresponding to each accommodating region 110;

[0132] S420: A pad structure 400 is formed at the through hole on the second reflective portion 520 corresponding to each accommodating region 110, so that the pad structure 400 is electrically connected to the substrate 100 through the through hole on the second reflective portion 520.

[0133] In subsequent step S500, an LED chip is transferred to each accommodating region 110, so that the LED chip 300 corresponding to each accommodating region 110 is bonded to the substrate 100 through the pad structure 400 of the accommodating region 110, and the device structure shown in FIG9(c) is obtained.

[0134] In this embodiment, if the light emitted from the LED chip 300 is directed toward the sidewall of the barrier unit 210, it will be reflected by the first reflective portion 510 covering the surface of the sidewall of the barrier unit 210, and the reflected light will be concentrated toward the position directly opposite the LED chip; if it is directed toward the surface of the substrate 100, it will be reflected by the second reflective portion 520 covering the accommodating area 100, and the reflected light will be directed toward the light-emitting surface of the display module. Thus, by providing a reflective layer 400 covering the surface of each barrier unit 210 sidewall and each accommodating area 110, the reflection of light toward the light-emitting surface of the display module is increased, greatly improving the display brightness and luminous efficiency of the display module.

[0135] Based on the above embodiments, optionally, in one embodiment of this application, the reflective layer 500 is an aluminum metal layer or a platinum metal layer, so that the reflective layer 500 has a high reflectivity.

[0136] Optionally, in another embodiment of this application, such as Figure 6 As shown, the reflective layer 500 includes N film layers arranged sequentially along its thickness direction. The (k+1)th film layer is farther away from the LED chip than the kth film layer, and the refractive index of the (k+1)th film layer is greater than that of the kth film layer. k is an integer not less than 1. By setting the reflective layer to include N film layers arranged sequentially along its thickness direction, and the film layer farther away from the LED has a larger refractive index, the reflectivity of light transmitted into the reflective layer is increased, thereby greatly improving the display brightness and luminous efficiency of the display module.

[0137] In summary, the display module provided by the embodiment of the present application sets a barrier wall layer on the surface of the substrate, and the barrier wall layer comprises a plurality of barrier wall units arranged in an array, each barrier wall unit comprises a ring-shaped closed sidewall, so that each barrier wall unit defines a rectangular accommodation area on the surface of the substrate, one accommodation area corresponds to one LED chip, in the length direction of the accommodation area, the length of the accommodation area is greater than the length of the LED chip and is not greater than 3 / 2 of the length of the LED chip, and in the width direction of the accommodation area, the width of the accommodation area is greater than the width of the LED chip and is not greater than 3 / 2 of the width of the LED chip, so that each LED chip can be limited by the barrier wall unit corresponding to the accommodation area in the transfer process to the corresponding accommodation area, the inclination and position deviation of the LED chip are reduced, the collimation of the LED chip bonded to the substrate is improved, and the bonding accuracy of the LED chip to the substrate in the transfer process is improved. Furthermore, the sidewall of the barrier wall unit is arranged around each LED chip, that is, the arrangement of the barrier wall unit can also prevent light interference between the LED chips. Further, the reflective layer is arranged on the sidewall of the barrier wall unit and the accommodation area, the reflection of light to the light emitting surface of the display module is increased, and the display brightness and light emitting efficiency of the display module are greatly improved.

[0138] The various parts of the specification are described in a parallel and progressive manner, and each part focuses on the difference from other parts. The same or similar parts between the various parts can be referred to each other.

[0139] The above description of the disclosed embodiments, the features described in each embodiment in the specification can be replaced or combined with each other, so that the person skilled in the art can realize or use the present application. Various modifications of the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A display module, characterized by The display module comprises: a substrate substrate; a barrier wall layer on the surface of the substrate substrate, the barrier wall layer is an inorganic thin film layer, the barrier wall layer comprises a plurality of barrier wall units arranged in an array, each barrier wall unit comprises a ring-shaped closed sidewall, so that each barrier wall unit defines a rectangular accommodation area on the surface of the substrate substrate; and a plurality of LED chips bonded to the substrate substrate, each accommodation area corresponds to an LED chip, the LED chip comprises an N electrode and a P electrode, the N electrode is bonded to the substrate substrate through a pad structure, and the P electrode is bonded to the substrate substrate through a pad structure; wherein, in a first direction, the length of the accommodation area is greater than the length of the LED chip, and is not greater than 3 / 2 of the length of the LED chip, in a second direction, the width of the accommodation area is greater than the width of the LED chip, and is not greater than 3 / 2 of the width of the LED chip, the first direction is parallel to the length direction of the accommodation area, and the second direction is parallel to the width direction of the accommodation area; in the direction perpendicular to the surface of the substrate substrate, the height of the sidewall of each barrier wall unit is not less than 1 / 2 of the height of the LED chip surrounded by the barrier wall unit; The display module further comprises: a reflective layer, the reflective layer comprises a first reflective part and a second reflective part formed integrally, the first reflective part covers the surface of the sidewall of each barrier wall unit, and the second reflective part covers each accommodation area; The LED chip is located on the side of the second reflective part corresponding to the accommodation area away from the substrate substrate, and the second reflective part corresponding to each accommodation area has a through hole, so that the LED chip is bonded to the substrate substrate through the through hole on the second reflective part.

2. The display module of claim 1, wherein, In a plane parallel to the surface of the substrate substrate, there is a preset distance between the sidewall of each barrier wall unit and the LED chip surrounded by the barrier wall unit, and the preset distance is not greater than 2 μm.

3. The display module of claim 1, wherein, Each barrier wall unit comprises a first sidewall, a second sidewall, a third sidewall and a fourth sidewall connected in sequence, and the first sidewall and the third sidewall extend along the first direction, and the second sidewall and the fourth sidewall extend along the second direction; a plurality of barrier wall units are arranged in a plurality of rows along the first direction, and a plurality of barrier wall units are arranged in a plurality of columns along the second direction; For any row, the fourth sidewall of the i-th barrier wall unit and the second sidewall of the i+1-th barrier wall unit are the same sidewall, i is an integer not less than 1; For any column, the third sidewall of the j-th barrier wall unit and the first sidewall of the j+1-th barrier wall unit are the same sidewall, j is an integer not less than 1.

4. The display module of claim 1, wherein, The reflective layer is an aluminum metal layer or a platinum metal layer.

5. The display module of claim 1, wherein, The reflective layer comprises N film layers arranged in sequence along the thickness direction of the reflective layer, wherein the k+1-th film layer is farther away from the LED chip than the k-th film layer, and the refractive index of the k+1-th film layer is greater than the refractive index of the k-th film layer, k is an integer not less than 1.

6. A method for manufacturing a display module, characterized by, The display module comprises: providing a substrate substrate; Forming a barrier layer on the surface of the substrate, the barrier layer being an inorganic thin film layer; Etching the barrier layer to form a plurality of barrier units arranged in an array, each of the barrier units comprising a ring-shaped closed sidewall, such that each of the barrier units defines a rectangular accommodation region on the surface of the substrate; Forming a pad structure in each of the accommodation regions; Transferring an LED chip to each of the accommodation regions, such that the LED chip corresponding to each of the accommodation regions is bonded to the substrate through the pad structure of the accommodation region, the LED chip comprising an N electrode and a P electrode, the N electrode being bonded to the substrate through one pad structure, and the P electrode being bonded to the substrate through one pad structure; Wherein, in a first direction, the length of the accommodation region is greater than the length of the LED chip, and is not greater than 3 / 2 of the length of the LED chip, and in a second direction, the width of the accommodation region is greater than the width of the LED chip, and is not greater than 3 / 2 of the width of the LED chip, the first direction being parallel to the length direction of the accommodation region, and the second direction being parallel to the width direction of the accommodation region; in a direction perpendicular to the surface of the substrate, the height of the sidewall of each of the barrier units is not less than 1 / 2 of the height of the LED chip surrounded by the barrier unit; Before forming the pad structure in each of the accommodation regions, the method further comprises: Forming a reflective layer, the reflective layer comprising integrally formed first reflective portions and second reflective portions, the first reflective portions covering the surfaces of the sidewalls of each of the barrier units, and the second reflective portions covering each of the accommodation regions; Forming the pad structure in each of the accommodation regions comprises: Forming a via hole on the second reflective portion corresponding to each of the accommodation regions; Forming the pad structure on the via hole on the second reflective portion corresponding to each of the accommodation regions, such that the pad structure is electrically connected to the substrate through the via hole on the second reflective portion.

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