Display module and display apparatus

Abstract

A display module and a display apparatus. The display module comprises: a substrate (1); miniature flip-chip LED chips (2) fixedly arranged on the top surface of the substrate; a lower light-transmitting layer (3), which at least covers an area between adjacent miniature flip-chip LED chips on the top surface of the substrate; a black optical layer (4), which covers the top surface of the lower light-transmitting layer, wherein each LED chip penetrates the top surface of the black optical layer; and an upper light-transmitting layer (5), which covers the top surface of the black optical layer and the top surfaces of the LED chips. In the display module, a black optical layer is sandwiched between two light-transmitting layers, thereby improving the display blackness of the display module, and also effectively ameliorating the phenomenon of mosaic display on a white screen.

Description

Display module and display device Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display module and a display device. Background Art

[0002] In the field of LED display technology, Mini COB (Chip On Board) display modules use a packaging technology that directly solders LED chips to PCB boards. However, due to limitations in the PCB manufacturing process, solder paste may overflow from the pads during the soldering process, causing the display to appear silvery-gray when turned off, affecting the overall black performance. In addition, when soldering the LED chip to the PCB, improper fixation may cause the chip to tilt, resulting in uneven surface flatness, further affecting the uniformity and brightness of the display. In practical applications, improving the visual consistency and display quality of the display module is a key focus. The black performance of the display when it is turned off is particularly critical. The selection of materials and the rationality of the structural design during the manufacturing process directly affect the ultimate performance of the display module. Therefore, optimizing these aspects to improve the visual performance of the display is a core focus of research and development in this field.

[0003] Application Contents

[0004] In view of the deficiencies of the above-mentioned related technologies, the purpose of this application is to provide a display module and a display device, aiming to solve the problem of poor blackness when the display module is in the off state or displays black in the prior art.

[0005] A display module, comprising:

[0006] A substrate, wherein a top surface of the substrate is provided with a plurality of pads;

[0007] A micro flip-chip LED chip, the micro flip-chip LED chip being fixed on the top surface of the substrate and electrically connected to the corresponding solder pad;

[0008] A lower light-transmitting layer, a black optical layer, and an upper light-transmitting layer are stacked in sequence; wherein:

[0009] The lower light-transmitting layer at least covers the area between adjacent micro flip-chip LED chips on the top surface of the substrate, and;

[0010] The black optical layer covers the top surface of the lower light-transmitting layer, and the top surface of the black optical layer is lower than the top surface of the micro flip-chip LED chip. The top surface of the black optical layer is lower than the top surface of the micro flip-chip LED chip.

[0011] The upper light-transmitting layer covers the top surface of the black optical layer and the top surface of the LED chip.

[0012] The above-mentioned display module is composed of a lower light-transmitting layer, a black optical layer and an upper light-transmitting layer stacked in sequence, so that the black optical layer is sandwiched between two transparent layers, which can block the solder pads and solder paste, making the blackness of the display module better when the screen is turned off or black is displayed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG1-1 is a schematic diagram of the structure of a display module in the prior art;

[0014] Figures 1-2 are schematic diagrams of the display module structure provided in an embodiment of the present application;

[0015] 1-3 are schematic structural diagrams of a display module provided in an embodiment of the present application having a transparent raised portion;

[0016] 1-4 are schematic diagrams of light emission from a micro flip-chip LED chip in a tilted state in a display module provided by an embodiment of the present application;

[0017] Figures 1-5 are schematic diagrams of a display module structure provided in an embodiment of the present application;

[0018] Figures 1-6 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0019] Figures 1-7 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0020] 1-8 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0021] Figures 1-9 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0022] Figures 1-10 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0023] Figures 1-11 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0024] Figures 1-12 are schematic diagrams of another display module structure provided in an embodiment of the present application;

[0025] FIG2-1 to FIG2-2 are schematic diagrams of a method for manufacturing a display module provided in an embodiment of the present application;

[0026] FIG2-3 and FIG2-4 are schematic side cross-sectional views of a display module manufactured by the method for manufacturing a display module provided in an embodiment of the present application;

[0027] 2-5 are schematic top views of a display module manufactured by the method for manufacturing a display module provided in an embodiment of the present application;

[0028] 2-6 are schematic diagrams showing further improvements to the manufacturing method of the display module provided in the embodiments of the present application;

[0029] 2-7 are schematic cross-sectional views of a display module manufactured by the method for manufacturing a display module provided in an embodiment of the present application;

[0030] 2-8 are schematic cross-sectional views of a display module manufactured by the method for manufacturing a display module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0033] In the related art, referring to Figure 1-1, in order to eliminate the impact of the substrate surface color and the solder pad color on the contrast of the display module and prevent the display module from appearing silver-gray in the off state and failing to display pure black, a black optical layer 4' is added to the display module to mask the color of the substrate 1' and solder pad 7' area, excluding the LED chip 2'. One approach is to apply the black optical layer 4' directly to the surface of the substrate 1', that is, the black optical layer 4' directly covers the substrate 1' and solder pad 7'. In this case, if the black optical layer 4' is thin, it cannot ensure complete coverage of the substrate 1' and solder pad 7' area. If there is solder paste on the solder pad surface, the silver-gray solder paste will reduce the blackness of the black optical layer. If the black optical layer is thick, it will directly affect the consistency of the light emitted from each side of the LED chip 2'. In particular, the LED chip 2' itself may be tilted after installation, resulting in significant differences in the path of the light emitted from its side through the black optical layer, thus causing uneven display effects on the display screen. 1-1 , there is a big difference in the path lengths of the black optical layer 4 'through which the light L1 and L2 on the left and right sides of the LED chip 2 'pass, resulting in a certain unevenness in the light output of the LED chip 2 ', causing a distorted screen on the actual display.

[0034] Based on this, the present application hopes to provide a solution that can solve the above technical problems, the details of which will be explained in the subsequent embodiments.

[0035] An embodiment of the present application provides a display module. Referring to FIG. 1-2 , the display module includes:

[0036] A substrate 1, with a plurality of pads 7 provided on the top surface of the substrate 1;

[0037] Multiple light-emitting elements 2 are fixed to the top surface of the substrate 1 and electrically connected to the corresponding pad 7. Figures 1-2 only representatively illustrate the structure in which one light-emitting element 2 among the multiple light-emitting elements is fixed to the substrate 1. The structure in which the other light-emitting elements 2 are connected to the substrate is the same as the structure in which the light-emitting elements 2 are connected to the substrate 1 shown in Figures 1-2.

[0038] The lower light-transmitting layer 3, the black optical layer 4 and the upper light-transmitting layer 5 are stacked in sequence; wherein:

[0039] The lower light-transmitting layer 3 at least covers the area between adjacent light-emitting elements 2 on the top surface of the substrate 1, and the top surface of the lower light-transmitting layer 3 is lower than the top surface of the light-emitting element 2;

[0040] The black optical layer 4 covers the top surface of the lower light-transmitting layer 3 , and the top surface of the black optical layer 4 is lower than the top surface of the light-emitting element 2 ;

[0041] The upper light-transmitting layer 5 covers the top surface of the black optical layer 4 and the top surface of the light-emitting element 2 .

[0042] The display module in the embodiment of the present application is generally used as a display panel of a display device, that is, as a display panel of an LED display screen. The light-emitting element 2 in the display module in the embodiment of the present application is a micro flip-chip LED chip 2, wherein the micro flip-chip LED chip 2 means that its size is smaller than that of a conventional flip-chip LED chip, and its specific type can be a mini LED chip or a micro LED chip, both of which are feasible in the embodiment of the present application. In this embodiment, the micro flip-chip LED chip 2 is fixed on the top surface of the substrate 1 and is electrically connected to the corresponding solder pad 7. In other embodiments, the light-emitting element 2 can also be other electroluminescent light-emitting elements. In this embodiment, one light-emitting element 2 includes only one micro flip-chip LED chip 2; but in other embodiments of the present application, one light-emitting element 2 can also include two or more micro flip-chip LED chips or include three or more micro flip-chip LED chips or include four or more micro flip-chip LED chips.

[0043] The specific positions of the solder pads 7 on the substrate 1 are typically arranged in an array, based on the number and location of the micro flip-chip LED chips 2 to be mounted. The solder pads 7 can be formed by applying a conductive layer to the surface of the insulating base layer of the substrate 1, then removing some of the metal through a process such as etching to expose the insulating layer, thereby obtaining the desired solder pad 7 area and corresponding circuitry to form a circuit layer. The micro flip-chip LED chips 2 are then mounted on the substrate 1 through a die-bonding process, achieving both a fixed connection and an electrical connection between the micro flip-chip LED chips 2 and the substrate 1.

[0044] In order to prevent the non-black parts such as the surface color of the substrate 1 and the color of the solder pad from affecting the blackness of the display module when displaying black, in the embodiment of the present application, a black optical layer 4 is covered on the display module except for the micro flip-chip LED chip 2 to cover the substrate 1 and the solder pad and other non-micro flip-chip LED chip 2 areas. Specifically, in the embodiment of the present application, the black optical layer 4 is arranged between two light-transmitting layers, namely the lower light-transmitting layer 3 directly covering the top surface of the substrate 1, and the upper light-transmitting layer 5 covering the black optical layer 4. That is, the lower light-transmitting layer 3, the black optical layer 4, and the upper light-transmitting layer 5 are stacked in sequence from close to the top surface of the substrate 1 to away from the top surface of the substrate 1. Among them, since the lower light-transmitting layer 3 and the upper light-transmitting layer 5 are themselves light-transmitting, most of the light emitted by the micro flip-chip LED chip 2 can pass through the upper light-transmitting layer 3 and the lower light-transmitting layer 5.

[0045] The lower light-transmitting layer 3 is positioned directly above the top surface of the substrate 1. Its coverage includes the area between adjacent miniature flip-chip LED chips 2, that is, it covers the gaps between each miniature flip-chip LED chip 2. This is equivalent to the lower light-transmitting layer 3 directly enveloping each miniature flip-chip LED chip 2 from the side. Furthermore, the top surface of the lower light-transmitting layer 3 is lower than the top surface of the miniature flip-chip LED chip 2. This means that the bottom area of ​​the miniature flip-chip LED chip 2 is enclosed by the lower light-transmitting layer 3, while its top area, including portions of the side surfaces and the entire light-emitting surface, is higher than the lower light-transmitting layer 3.

[0046] This structure allows the lower light-transmitting layer 3 to cover the top surface of the substrate 1 while also avoiding the problems of uneven or incomplete coverage of the black optical layer 4 when directly covering the substrate surface due to low surface flatness. If the black optical layer 4 is too thin, this can lead to poor brightness and display uniformity. In this embodiment, a lower light-transmitting layer 3 is placed beneath the black optical layer 4 to improve the flatness of the substrate 1. This allows a thinner black optical layer 4 to achieve optimal shielding of the top surface of the substrate 1, the solder pads 7, and the solder paste.

[0047] In some optional embodiments, referring to Figures 1-3, the top surface of the micro-flip LED chip 2 may also have a transparent raised portion 6, with the middle region of the transparent raised portion 6 being higher than its edge regions. The transparent raised portion 6 is inherently light-transmissive and has minimal impact on the light output of the micro-flip LED chip 2. Furthermore, the transparent raised portion 6 is shaped such that its middle region is higher and its edge regions are lower. The transparent raised portion 6 is formed during the heat lamination process of the black optical layer 4, when the micro-flip LED chip 2 is squeezed, leaving a portion of the lower light-transmitting layer 3 remaining on the top of the micro-flip LED chip 2. Due to the high middle and low edge shape of the transparent raised portion 6, the black optical layer 4 is smoothly squeezed to the side of the micro-flip LED chip 2, covering the area between the micro-flip LED chips 2. This reduces or even prevents the black optical layer 4 from remaining on the top surface of the micro-flip LED chip 2, which could reduce the brightness of the micro-flip LED chip 2. In actual applications, if the black optical layer 4 is completely squeezed onto the side of the micro flip-chip LED chip 2 without any residue, the transparent raised portion 6 is visually invisible; if most of the black optical layer 4 is squeezed onto the side of the micro flip-chip LED chip 2, with a small portion remaining above the micro flip-chip LED chip 2, at least a partial outline of the transparent raised portion 6 can be seen.

[0048] The black optical layer 4 overlies the lower light-transmitting layer 3. Because the lower light-transmitting layer 3 is positioned away from the micro-flip-chip LED chips 2, the corresponding black optical layer 4 also surrounds each micro-flip-chip LED chip 2, wrapping around the sides of the micro-flip-chip LED chips 2. Because the black optical layer 4 overlies the lower light-transmitting layer 3, the thickness of the black optical layer 4 can be reduced without worrying about it being unable to block solder paste protruding from the substrate 1. In this embodiment, because the lower light-transmitting layer 3 is first laid on top of the substrate 1 and the black optical layer 4 is positioned above the lower light-transmitting layer 3, the surface of the lower light-transmitting layer 3 is relatively flat. This allows the black optical layer 4, even when very thin, to cover the lower light-transmitting layer 3 and block solder pads and solder paste.

[0049] In the embodiment of the present application, the top surface of the black optical layer 4 is also lower than the top surface of the light-emitting element 2, indicating that the top area of ​​the micro flip-chip LED chip 2, including part of the side surface and the entire light-emitting surface, is higher than the black optical layer 4. In this case, the black optical layer 4 will not cover the light in the main light-emitting direction of the micro flip-chip LED chip 2, and because the thickness of the black optical layer 4 is relatively thin, the light emitted from each side of the light-emitting element 2 passes through the black optical layer 4 at a similar distance, so its display effect is also relatively uniform, effectively improving the screen distortion phenomenon of the display screen. Please refer to Figures 1-4 for details, which show the state of the light-emitting element 2 tilted after assembly. The thickness of the black optical layer 4 through which the side light output L3 and L4 passes is basically the same. Therefore, in this state, the light output of the light-emitting element 2 is more uniform, and the screen distortion phenomenon is improved.

[0050] The black optical layer 4 is also covered with an upper light-transmitting layer 5, wherein the upper light-transmitting layer 5 is different from the lower light-transmitting layer 3 and the black optical layer 4 in that the area and shape of the upper light-transmitting layer 5 not only cover the black optical layer 4 thereunder, but also cover the exposed portion of the micro flip-chip LED chip 2 not covered by the black optical layer 4, thereby making the entire display module appear as an integral structure to improve the consistency of light output.

[0051] In some optional embodiments, please refer to Figures 1-5. In order to adapt to the tilt of the light-emitting element 2 after it is installed on the substrate 1 as much as possible, the height of the top surface of the black optical layer 4 is lower than 1 / 4 of the height of the substrate 21 of the light-emitting element 2. The position of the dotted line X1 in Figures 1-5 is 1 / 4 of the substrate height; the position of the dotted line X2 is 1 / 2 of the substrate height. In this application, the substrate height is measured in the direction of the electrode of the light-emitting element with the top surface of the substrate as the reference. The most perfect state for the light-emitting element 2 to be installed on the substrate 1 is that its top light-emitting surface is parallel to the top surface of the substrate 1. However, in actual operation, it is difficult to completely avoid the deflection of the light-emitting element 2. This deflection will cause an angle to be formed between its top light-emitting surface and the top surface of the substrate 1. According to the assembly accuracy requirements, this angle is usually small. In order to solve the problem of still being able to achieve uniform light emission when the light-emitting element 2 is deflected, a certain height difference can be set between the top surface of the black optical layer 4 and the top surface of the light-emitting element 2. This height difference ensures that even if the micro flip-chip LED chip 2 is tilted within a certain range, the black optical layer 4 is always below the top surface of the light-emitting element 2, without affecting the normal light emission from the top light-emitting surface of the light-emitting element 2. The thickness of the black optical layer 4 required for the side light to pass through is also consistent, thereby improving the display uniformity of the display panel and improving the screen distortion phenomenon. Taking into account the display effect and process difficulty, the height difference between the top surface of the black optical layer 4 and the top surface of the micro flip-chip LED chip 2 can generally be greater than or equal to 1 / 2 the height of the substrate 21 of the micro flip-chip LED chip 2. This can minimize the processing accuracy required for the display module while ensuring the display effect, thereby improving the yield rate.

[0052] As shown in Figures 1-6, to achieve the optimal display effect of the display module, the ideal design is for the black optical layer 4 to be positioned in alignment with the light-emitting layer 22 of the micro flip-chip LED chip 2. Specifically, the height of the top surface of the black optical layer 4 is no greater than the height of the light-emitting surface of the micro flip-chip LED chip 2. Preferably, the top and bottom surfaces of the black optical layer 4 are opposite the top and bottom surfaces of the light-emitting layer 22 of the micro flip-chip LED chip 2, respectively. While the top and bottom surfaces of the black optical layer 4 are opposite the top and bottom surfaces of the light-emitting layer 22 of the micro flip-chip LED chip 2, it is not strictly required that the top and bottom surfaces of the black optical layer 4 be coplanar. In practice, since the micro flip-chip LED chip 2 inevitably tilts after being mounted on the substrate 1, the top and bottom surfaces of the black optical layer 4 can be positioned approximately in the same plane as the top and bottom surfaces of the light-emitting layer 22 of the micro flip-chip LED chip 2. Furthermore, the thickness of the black optical layer 4 is not necessarily identical to that of the light-emitting layer 22. The desired dimensions can be determined based on factors such as display effect and process cost. Specifically, in some typical examples, the thickness of the black optical layer 4 can be 3 μm to 10 μm. Taking into account actual display effects and processing accuracy, the thickness of the black optical layer 4 can be set to 5 μm. Of course, display modules made from micro flip-chip LED chips 2 of different specifications and sizes may have different size requirements. The corresponding size can be set according to actual conditions during product manufacturing.

[0053] In some optional embodiments, the transmittance of the black optical layer 4 can be adjusted to the desired specifications based on the different display brightness and blackness requirements of the display module. For example, when the blackness of the display module needs to be improved, the transmittance of the black optical layer 4 can be set to 0-5%, that is, it is essentially opaque, which can maximize the blackness of the display when the display module is not illuminated. Alternatively, the transmittance of the black optical layer 4 can be set to 10%-30%, preferably 20%-30%, for example, it can be 20%. In this case, the black optical layer 4 has a certain degree of transmittance, which can improve the display brightness of the display module. In some optional embodiments, the thickness of the lower light-transmitting layer 3 is 20μm to 45μm. The thickness of the lower light-transmitting layer 3 is related to the desired location and thickness of the black optical layer 4, which in turn is related to the actual display effect required by the display module. Generally speaking, the thickness of the lower light-transmitting layer 3 ranges from 20μm to 45μm, which is greater than the thickness of the black optical layer 4.

[0054] To minimize the effect of the light-transmitting layer on the light output of the micro flip-chip LED chip 2, the transparency of the lower light-transmitting layer 3 and the upper light-transmitting layer 5 can be set to be as high as possible. In some optional embodiments, the transparency of the lower light-transmitting layer 3 and the upper light-transmitting layer 5 can be set to greater than 90%. Silicon dioxide powder can also be added to the lower light-transmitting layer 3 and the upper light-transmitting layer 5 to achieve a light diffusion effect, further improving display brightness.

[0055] In the present application, the lower light-transmitting layer 3 and the upper light-transmitting layer 5 can be either completely transparent or translucent. However, compared with the black optical layer 4, these two layers are visually distinct and different, and have significantly different light transmittance. Specifically, the color of the black optical layer 4 is visually significantly darker than that of the lower light-transmitting layer 3 and the upper light-transmitting layer 5, and its light transmittance is also significantly lower than that of the lower light-transmitting layer 3 and the upper light-transmitting layer 5, so it has better light-shielding performance. It should be noted that the light transmittance of the lower light-transmitting layer 3 and the upper light-transmitting layer 5 is based on the black optical layer 4 as a reference, and it is not required that the lower light-transmitting layer 3 and the upper light-transmitting layer 5 must be completely transparent.

[0056] In some optional embodiments, to ensure tight bonding between the layers and stable performance of the display module, the lower light-transmitting layer 3, the black optical layer 4, and the upper light-transmitting layer 5 can all be airtight glue layers. Specifically, the glue layer can be epoxy resin, including but not limited to silicone, silicone-epoxy modified resins, acrylic resins, polyethylene resins, and the like.

[0057] In an optional embodiment, referring to Figures 1-7, the black optical layer 4 contacts the side of the micro flip-chip LED chip 2, and the portion of the black optical layer 4 that contacts the side of the micro flip-chip LED chip 2 is recessed downward, and the space 41 below the micro flip-chip LED chip 2 is also partially filled with the black optical layer. This allows the black optical layer 4 to be tightly attached to the micro flip-chip LED chip 2, more fully covering the solder pad.

[0058] In one embodiment, referring to Figures 1-8, the black optical layer 4 contacts the side of the micro flip-chip LED chip 2, and the portion of the black optical layer 4 that contacts the side of the micro flip-chip LED chip 2 is tilted upward or lies horizontally relative to the side of the micro flip-chip LED chip 2. The space 41 below the micro flip-chip LED chip 2 is free of the black optical layer. This ensures that the black optical layer 4 is in close contact with the micro flip-chip LED chip 2, providing more adequate coverage of the solder pads.

[0059] In one embodiment, referring to Figures 1-9, the black optical layer 4 does not contact or does not completely contact the side surfaces of the micro flip-chip LED chip 2. The space 41 below the micro flip-chip LED chip 2 is free of the black optical layer 4. The portion of the black optical layer 4 that is adjacent to the side surfaces of the micro flip-chip LED chip 2 is tilted upward or lies horizontally relative to the side surfaces of the micro flip-chip LED chip 2. This creates at least some gap between the black optical layer 4 and the side surfaces of the micro flip-chip LED chip 2. This gap is small enough that light reflected from the solder pads or solder paste cannot be clearly seen through the gap. However, when the micro flip-chip LED chip 2 is illuminated, some light will be emitted from its side surfaces, thereby improving display brightness.

[0060] In an optional embodiment, as shown in FIG1-10 , a gray optical layer 8 may be further provided on the upper light-transmitting layer. The light transmittance of the gray optical layer 8 is higher than that of the black optical layer 4, but lower than that of the upper light-transmitting layer 5 and the lower light-transmitting layer 4. The light transmittance of the gray optical layer 8 is preferably 60%-88%, which slightly darkens the surface of the display device and reduces the whitening phenomenon of the display device surface. Although there is a clear dividing line between the gray optical layer 8 and the upper light-transmitting layer 5 in the embodiment shown in FIG1-10 , in an embodiment, as shown in FIG1-10 , during the process of providing the gray optical layer 8 on the upper light-transmitting layer 5 through a heat lamination process, the gray optical layer 8 may also interact and fuse with the portion of the upper light-transmitting layer 5 that contacts the gray optical layer 8, thereby eliminating a clear dividing line and giving the appearance of a gradient gray effect.

[0061] In an optional embodiment, referring to FIG1-12 , the light-emitting element 2 includes three micro flip-chip LED chips 2-1, 2-2, and 2-3 emitting light of different colors. The three micro flip-chip LED chips emitting light of different colors may emit red, green, and blue, respectively, and may together form a pixel unit. If the spacing between the three micro flip-chip LED chips is very small, the black optical layer may not be able to fit into the gaps between the chips. Therefore, the three micro flip-chip LED chips may penetrate the black optical layer 4 as a whole. However, if the gaps between the micro flip-chip LED chips are large enough, the composite black optical film 200 may also fit into the gaps between the micro flip-chip LED chips.

[0062] The display device provided in the embodiment of the present application has a display module in which a lower light-transmitting layer 3, a black optical layer 4 and an upper light-transmitting layer 5 are stacked in sequence, so that the black optical layer 4 is sandwiched between the two light-transmitting layers. While ensuring the display blackness of the display module, the thickness of the black optical layer 4 is reduced, thereby shortening the path of the light emitted by the light-emitting element 2 through the black optical layer 4, thereby minimizing the problem of uneven light output caused by the tilt of the LED chip 2, and effectively improving the white screen display flower screen phenomenon.

[0063] An embodiment of the present application further provides a display device (not shown), which includes a driving module and the display module in the embodiment of the present application, wherein the driving module is connected to the display module to drive and control the display module.

[0064] 2-1 and 2-2 , an embodiment of the present application provides a method for manufacturing a display module. This embodiment can be implemented independently of the other embodiments.

[0065] The manufacturing method of the display module provided in this embodiment includes: providing a light board 100, a composite black optical film 200 and a translucent protective film 50; wherein the light board 100 includes a substrate 1, and a plurality of light-emitting elements 2 arranged on the substrate 1; the composite black optical film 200 includes a black optical layer 4 and an upper translucent layer 3 and a lower translucent layer 4 respectively covering the upper surface and the lower surface of the black optical layer 4; as shown in Figure 2-1, the composite black optical film 200 is first covered and pressed on the light board 100, so that the top light-emitting surfaces of the plurality of light-emitting elements penetrate the black optical layer 4 of the composite black optical film 200 (refer to Figure 2-2) and then the translucent protective film 50 is covered and pressed on the upper surface of the composite black optical film 200, and the upper surface of the translucent protective film 50 is made flat.

[0066] This embodiment provides a method for manufacturing a display module, and schematic side structure diagrams of a display module 1000 are shown in FIG. 2-3 and FIG. 2-4 .

[0067] In this embodiment, referring to Figures 2-5, a plurality of light emitting elements 2 are arranged in a rectangular array on the surface of the substrate.

[0068] In the manufacturing method described above, the thickness of the black optical layer 4 in the composite black optical film 200 gradually decreases due to being squeezed by the top of the light-emitting element 2, the lower light-transmitting layer 4, and the upper light-transmitting layer 220, so that the tops of multiple light-emitting elements 2 penetrate the black optical layer 4, which can reduce or even avoid the black optical layer 4 remaining on the top of the light-emitting element 2 to block the light-emitting surface of the light-emitting element 2, thereby making the light-emitting effect of the light-emitting element 2 more consistent. On the other hand, the side of the light-emitting element 2 surrounded by the black optical layer can block the area except the top area of ​​the light-emitting element, so that the blackness of the display module is better when the screen is off or displays black. In addition, the present method prefabricates the upper light-transmitting layer, the black optical layer, and the upper optical layer into a composite black optical film 200. When manufacturing the display module, the black optical film 200 is directly pressed onto the surface of the substrate 1 and multiple light-emitting elements 2 through a hot lamination process, without the need to set them layer by layer, which has the advantage of simple manufacturing.

[0069] In the above manufacturing method, there are two situations in which the tops of the multiple light-emitting elements 2 penetrate the black optical layer 4. One situation is that the tops of the multiple light-emitting elements 2 first penetrate the lower light-transmitting layer 4 and then penetrate the black optical layer 4. In this situation, although the light-emitting elements 2 may contact the black light-transmitting layer 220 after penetrating the lower light-transmitting layer 4, the black light-transmitting layer 220 will be squeezed by the light-emitting elements 2 in the process of penetrating the lower light-transmitting layer, making the thickness of the black light-transmitting layer 220 smaller and smaller. At the same time, the black light-transmitting layer 220 will also be squeezed by the upper light-transmitting layer 3, thereby further squeezing the black light-transmitting layer. When the light-emitting elements 2 penetrate the black light-transmitting layer 220, the black light-transmitting layer is reduced or avoided to remain on the top of the light-emitting elements 2.

[0070] Another scenario is that the tops of the multiple light-emitting elements 2 push against a portion of the lower light-transmitting layer 4 and penetrate the black optical layer 4 together. In this case, due to the barrier effect of the lower light-transmitting layer 4, the multiple light-emitting elements 2 will not come into contact with the black optical layer 4. Furthermore, due to the mutual compression between the multiple light-emitting elements 2 and the upper light-transmitting layer 3, the tops of the multiple light-emitting elements 2 penetrate the black optical layer 4, allowing the lower light-transmitting layer 4 and the upper light-transmitting layer 3 to meet at the tops of the multiple light-emitting elements 2. As a result, the black optical layer 4 will not remain on the tops of the multiple light-emitting elements 2.

[0071] As a further refinement of the above-mentioned manufacturing method, when the composite black optical film 200 is covered and pressed onto the lamp board 100, the composite black optical film 200 is pressed onto the lamp board 100 under a negative pressure and heating environment and under the action of extrusion pressure, so that the composite black optical film 200 is softened so that the top light-emitting surfaces of multiple light-emitting elements 2 penetrate the black optical layer 4 under the extrusion pressure.

[0072] Under negative pressure, the composite black optical film 200 is more closely attached to the light board 100. In combination with the heating environment, the composite black optical film 200 softens into a paste with a certain fluidity, which can reduce bubbles between the composite black optical film 200 and the surface of the substrate. Under extrusion force, for example, when pressure is applied to the upper light-transmitting layer 3 of the composite black optical film 200 on the upper surface of the light board, the tops of the multiple light-emitting elements 2 squeeze the lower light-transmitting layer 4 and the black optical layer 4 upward. Since the black optical layer 4 is squeezed, it will flow to the periphery of the tops of the multiple light-emitting elements 2, thereby reducing or even avoiding the residue on the tops of the multiple light-emitting elements 2, thereby reducing or even avoiding blocking the light-emitting surface of the tops of the multiple light-emitting elements 2, thereby improving the light-emitting effect of the multiple light-emitting elements 2. In the above steps, the lower light-transmitting layer 4 plays a role of buffering and lubrication, making it easier for the black optical layer 4 to flow to the periphery of the tops of the multiple light-emitting elements 2, thereby making it easier for the multiple light-emitting elements 2 to penetrate the black optical layer 4.

[0073] In this embodiment, the multiple light-emitting elements 2 do not penetrate the lower light-transmitting layer 4. Instead, they are lifted up by the multiple light-emitting elements 2, penetrate the black optical layer 4 together, and contact and fuse with the upper light-transmitting layer 3. In other embodiments, the multiple light-emitting elements 2 can also penetrate the lower light-transmitting layer 4 after penetrating the black optical layer 4, and a portion of the upper light-transmitting layer 3 moves downward to connect and fuse with the lower light-transmitting layer 4.

[0074] In this embodiment, the lower light-transmitting layer 4 and the upper light-transmitting layer 3 are made of the same material, so that the lower light-transmitting layer 4 and the upper light-transmitting layer 3 are more tightly connected when in contact and fused, thereby avoiding delamination and peeling off after long-term use.

[0075] As a further refinement of the above manufacturing method, when the light-transmitting protective film 50 is covered and pressed onto the upper surface of the composite black optical film 200, the light-transmitting protective film 50 is pressed onto the composite black optical film 200 under negative pressure and heating environment and under the action of extrusion force.

[0076] Under the action of negative pressure, the light-transmitting protective film 50 is more easily adhered to the upper surface of the composite black optical film 200. Combined with the heating environment, the light-transmitting protective film 50 is softened into a paste, thereby filling the uneven surface formed on the upper surface of the composite black optical film 200 and reducing the bubbles between the black optical film 200 and the light-transmitting protective film 50, so that the outer surface of the display module finally manufactured is smooth, which can not only protect the display module but also facilitate the cleaning of dust on the surface of the display module.

[0077] In one embodiment, referring to Figures 2-4 , the light-transmitting protective film 50 and the upper light-transmitting layer 3 of the composite black optical film 200 are made of the same material. After the light-transmitting protective film 50 is covered and pressed onto the upper surface of the composite black optical film 200, the light-transmitting protective film 50 and the upper light-transmitting layer of the composite black optical film 200 are integrated and become part of the upper light-transmitting layer. This prevents delamination between the light-transmitting protective film 50 and the composite black optical film 200, providing the advantage of good sealing.

[0078] In one embodiment, the composite black optical film 200 is covered and pressed onto the light board 100 so that when the top light-emitting surfaces of the plurality of light-emitting elements 2 penetrate the lower light-transmitting layer 4 and the black optical layer 4 of the composite black optical film 200, the plurality of light-emitting elements 2 do not penetrate the upper light-transmitting layer 3 of the composite black optical film 200. Thus, a protective layer is always present on the top surfaces of the plurality of light-emitting elements 2.

[0079] In this embodiment, in order to make the composite black optical film 200 fit more closely with the light board 100, the thickness of the composite black optical film 200 should be as small as possible. After the thinner composite black optical film 200 is pressed onto the light board 100, since multiple light-emitting elements 2 protrude from the substrate, the surface of the composite black optical film 200 is an uneven surface. Therefore, in order to allow the translucent protective film 50 to fully fill the uneven surface of the composite black optical film 200, the thickness of the translucent protective film 50 should be greater than the thickness of the composite black optical film 200.

[0080] In order to facilitate the plurality of light-emitting elements 2 to penetrate the black optical layer 4 , the thickness of the black optical layer 4 is the smallest in the composite black optical film 200 .

[0081] In this embodiment, the transmittance of the black optical layer 4 is 0-5% or 10-30%. When the blackness of the display module needs to be improved, the transmittance of the black layer 4 can be set to 0-5%, that is, it is essentially opaque, which can maximize the blackness of the display when the display module is not lit. Alternatively, the transmittance of the black layer 4 can be set to 10-30%, for example, it can be 20%. In this case, the black layer 4 has a certain degree of transmittance, which can improve the display brightness of the display module.

[0082] In actual production, due to issues with the film manufacturing process, it is easiest to achieve a transmittance of 20%-30% for the black optical layer 4. However, if the transmittance of the black layer 4 is too low, the light uniformity of each light-emitting element will be poor, resulting in low height uniformity of the black optical layer 4 on the side of the chip. Slightly increasing the transmittance of the black optical layer can alleviate this defect. Therefore, in a preferred embodiment, the transmittance of the black layer 4 is 20%-30%.

[0083] Since the lower light-transmitting layer 4 can play a lubricating and buffering role when multiple light-emitting elements 2 squeeze the lower light-transmitting layer 4 and the black optical layer 4, it reduces or even prevents the black optical layer 4 from remaining on the top surface of the light-emitting element 2, and multiple light-emitting elements 2 penetrate the black optical layer 4, so that the light-emitting effect of each light-emitting element 2 is consistent.

[0084] Among the multiple light-emitting elements 2 , each light-emitting element 2 includes at least one, at least two, at least three, or at least four or more flip-chip LED chips.

[0085] In some optional embodiments, during the process of setting the black optical layer 4 using a heat lamination process, under a negative pressure environment, part of the black optical layer 4 will be sucked into the space 41 below the micro flip-chip LED chip 2, and the following situations will occur: (1) Referring to Figures 1-7, if the thickness of the lower light-transmitting layer 3 is too thin, so that part of the black optical layer 4 also fills the space 41 below the micro flip-chip LED chip 2, the black optical layer 4 will contact the side of the micro flip-chip LED chip 2, and the part of the black optical layer 4 that contacts the side of the micro flip-chip LED chip 2 will be concave downward. In this way, the black optical layer 4 can be closely attached to the micro flip-chip LED chip 2, and the solder pad can be more fully covered. (2) Referring to FIG1-8 , if the thickness of the lower light-transmitting layer 3 is sufficient to fill the space 41 below the micro flip-chip LED chip 2, the black optical layer 4 is not required, and the thickness of the lower light-transmitting layer 3 is not sufficient to isolate the black optical layer from the surface of the micro flip-chip LED chip 2, the black optical layer 4 may contact the side of the micro flip-chip LED chip 2, but the portion of the black optical layer 4 that contacts the side of the micro flip-chip LED chip 2 may be tilted upward or horizontally opposed to the side of the micro flip-chip LED chip 2. This may also allow the black optical layer 4 to be in close contact with the micro flip-chip LED chip 2, providing more adequate coverage of the soldering pad. (3) Referring to Figures 1-9, if the thickness of the lower light-transmitting layer 3 is sufficient to fill the space 41 below the micro flip-chip LED chip 2, the black optical layer 4 is not required, and the thickness of the lower light-transmitting layer 3 is thicker than in case (2), sufficient to isolate the black optical layer from the surface of the micro flip-chip LED chip 2, which will result in the black optical layer 4 not being in contact with or not being in complete contact with the side of the micro flip-chip LED chip 2, but the portion of the black optical layer 4 close to the side of the micro flip-chip LED chip 2 is tilted upward or horizontally opposite to the side of the micro flip-chip LED chip 2. This will result in at least some gaps between the black optical layer 4 and the side of the micro flip-chip LED chip 2. These gaps are small enough that the light reflected by the solder pad or solder paste cannot be seen from the gaps. However, when the micro flip-chip LED chip 2 is lit, some light will be emitted from its side, which can improve the display brightness.

[0086] As a further improvement to this embodiment, referring to Figures 2-6 , the above manufacturing method further includes overlaying a gray optical layer 8 on the light-transmitting protective film 50. Gray optical layer 8 is deposited on the gray optical layer through a thermal lamination process. The light transmittance of gray optical layer 8 is higher than that of the black optical layer, but lower than that of the upper light-transmitting layer and the lower light-transmitting layer.

[0087] The light transmittance of the gray optical layer 8 is preferably 60%-88%, which slightly darkens the surface of the display device and reduces the whitening effect of the display device surface. In one embodiment, referring to Figures 2-7, there is a clear boundary between the gray optical layer 8 and the transparent protective film 50. However, in one embodiment, referring to Figures 2-8, during the molding process of the gray optical layer 8 onto the transparent protective layer 300, the gray optical layer 8 and the transparent protective layer 300 may partially blend together, thereby eliminating the clear boundary and giving the appearance of a gradient gray effect.

[0088] It should be understood that the application of this application is not limited to the above examples. For ordinary technicians in this field, they can make improvements or changes based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A display module, characterized in that: The display module comprises: A substrate, wherein a plurality of pads are disposed on the top surface of the substrate; A plurality of light-emitting elements, each of which is fixed on the top surface of the substrate and electrically connected to the corresponding pad; A lower light-transmitting layer, a black optical layer and an upper light-transmitting layer are stacked in sequence; wherein: The lower light-transmitting layer at least covers the area between adjacent light-emitting elements on the top surface of the substrate; The black optical layer covers the top surface of the lower light-transmitting layer, and each of the light-emitting elements penetrates the top surface of the black optical layer, and the top surface of the black optical layer is lower than the top surface of the light-emitting element; The upper light-transmitting layer covers the top surface of the black optical layer and the top surface of the LED chip.

2. The display module according to any one of claims 1, characterized in that: Among the plurality of light-emitting elements, each light-emitting element includes at least one, at least two, at least three, or at least four or more flip-chip LED chips.

3. The display module according to claim 1, wherein: The thickness of the black optical layer is smaller than that of the upper light-transmitting layer and the lower light-transmitting layer.

4. The display module according to claim 1, wherein: The thickness of the black optical layer is 3 μm to 10 μm; the thickness of the lower light-transmitting layer is 20 μm to 45 μm.

5. The display module according to any one of claims 1, characterized in that: The transparency of the lower light-transmitting layer and the upper light-transmitting layer is greater than 90%.

6. The display module according to any one of claims 1, characterized in that: The black optical layer is upwardly tilted around the plurality of light emitting elements.

7. The display module according to any one of claims 1, characterized in that: The surfaces of the plurality of light emitting elements are blocked from the black optical layer by the lower light-transmitting layer.

8. The display module according to any one of claims 1, characterized in that: In the upper light-transmitting layer on the top of the light-emitting element, a light-transmitting protrusion whose middle area is higher than its edge area is provided on the top surface facing the light-emitting element.

9. The display module according to any one of claims 1, characterized in that: The upper light-transmitting layer is provided with a gray optical layer thereon, and the light transmittance of the gray optical layer is higher than the light transmittance of the black optical layer, and lower than the light transmittance of the upper light-transmitting layer.

10. The display module according to any one of claims 1, characterized in that: The light transmittance of the gray optical layer is 60% to 88%.

11. A display device, characterized in that: The display device comprises a driving module and the display module according to any one of claims 1 to 10, wherein the driving module is connected to the display module to drive and control the display module.

12. A method for manufacturing a display module, characterized in that: include: Provide light board, composite black optical film and transparent protective film; The light board comprises a substrate, and a plurality of light-emitting elements arranged on the substrate; The composite black optical film includes a black optical layer and an upper light-transmitting layer and a lower light-transmitting layer respectively covering the upper surface and the lower surface of the black optical layer; the composite black optical film is first covered and pressed onto the light board so that the top light-emitting surfaces of the multiple light-emitting elements at least penetrate the black optical layer of the composite black optical film, and then the transparent protective film is covered and pressed onto the upper surface of the composite black optical film, so that the upper surface of the transparent protective film is a flat surface.

13. The manufacturing method according to claim 12, characterized in that: When the composite black optical film is covered and pressed onto the lamp board, the composite black optical film is pressed onto the lamp board under negative pressure and heating environment and under the action of extrusion force, so that the composite black optical film softens so that the top light-emitting surfaces of multiple light-emitting elements penetrate the black optical layer under the extrusion force.

14. The manufacturing method according to claim 12, characterized in that: When the transparent protective film is covered and pressed onto the upper surface of the composite black optical film, the transparent protective film is pressed onto the composite black optical film under negative pressure and heating environment and under the action of extrusion force.

15. The manufacturing method according to claim 12, characterized in that: The transparent protective film and the upper light-transmitting layer of the composite black optical film are made of the same material; after the transparent protective film is covered and pressed onto the upper surface of the composite black optical film, the transparent protective film and the upper light-transmitting layer of the composite black optical film are integrated and become a part of the upper light-transmitting layer.

16. The manufacturing method according to claim 12, characterized in that: The thickness of the black optical layer is smaller than that of the upper light-transmitting layer and the lower light-transmitting layer.

17. The manufacturing method according to claim 12, characterized in that: The method also includes the step of covering the transparent protective layer with a gray optical layer; the light transmittance of the gray optical layer is higher than the light transmittance of the black optical layer, and lower than the light transmittance of the upper light-transmitting layer.

18. The manufacturing method according to claim 15, characterized in that: The light transmittance of the gray optical layer is 60% to 88%.

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