LED display module and manufacturing method thereof

Abstract

The application provides an LED display module and a manufacturing method thereof. The LED display module comprises a substrate, a plurality of light emitting units arranged on one side surface of the substrate, the light emitting units comprising a plurality of light emitting chips, a reflection structure comprising a support body and a reflection part, the support body having a plurality of bowl-shaped light emitting parts penetrating up and down and having a large opening and a small bottom, the bowl-shaped light emitting parts being arranged one-to-one corresponding to the light emitting units, the cross-sectional shape of the inner side wall of the bowl-shaped light emitting part being an asymmetric race track shape, the light emitting unit being located at the bottom of the bowl-shaped light emitting part, the bowl-shaped light emitting part having a major axis and a minor axis perpendicular to each other, the plurality of light emitting chips being arranged along the major axis, and the inner side wall of the bowl-shaped light emitting part being formed with the reflection part, and a transparent protective layer arranged in the bowl-shaped light emitting part and covering the light emitting unit. The application solves the problems of poor display brightness and color effect of Micro LED in the related art.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically, to an LED display module and its manufacturing method. Background Technology

[0002] With the rapid development of Micro LED display technology in high-end applications such as ultra-large screen displays, AR / VR, automotive, and wearable devices, higher requirements are being placed on the optical performance of display modules, including high resolution, high brightness, excellent color consistency, and thinner and lighter structures. Currently, in mainstream Micro LED display modules, the light-emitting chips are arrayed using mass transfer technology. The emitted light is mixed by scattering homogenizing materials (such as phosphors or diffusion films) and then separated into RGB colors by independent color filters. In this structure, each layer is independently manufactured and assembled, resulting in significant tolerance accumulation between layers, leading to pixel-level alignment deviations. Simultaneously, crosstalk occurs within the package, causing color aliasing between adjacent pixels. The filters struggle to effectively remove stray light, thus reducing color gamut coverage and contrast. Uneven light emission also results in poor image uniformity and color purity.

[0003] In other words, Micro LED displays suffer from poor brightness and color display performance in related technologies. Summary of the Invention

[0004] The main objective of this invention is to provide an LED display module and its manufacturing method to solve the problem of poor brightness and color performance in Micro LED displays in related technologies.

[0005] To achieve the above objectives, according to one aspect of the present invention, an LED display module is provided, comprising: a substrate; a plurality of light-emitting units disposed on one side surface of the substrate, the light-emitting units including a plurality of light-emitting chips; a reflective structure including a supporting body and a reflective portion, the reflective structure and the light-emitting units being disposed on the same side of the substrate, the supporting body having a plurality of cup-shaped light-emitting portions extending vertically and vertically with large openings and small bottoms, the cup-shaped light-emitting portions being disposed one-to-one with the light-emitting units, the cross-sectional shape of the inner sidewall of the cup-shaped light-emitting portion being asymmetrical racetrack shape, the light-emitting units being located at the bottom of the cup-shaped light-emitting portion, the cup-shaped light-emitting portion having mutually perpendicular major and minor axes, the plurality of light-emitting chips being arranged along the major axis, the inner sidewall of the cup-shaped light-emitting portion forming a reflective portion for emitting light emitted by the light-emitting chips perpendicularly to the substrate; and a transparent protective layer disposed within the cup-shaped light-emitting portion and covering the light-emitting units.

[0006] Furthermore, the inner wall of the cup-shaped light-emitting portion is a parabola. Along a direction perpendicular to the substrate and parallel to the minor axis, at a cross-section of at least one of the plurality of light-emitting chips, the inner wall of the cup-shaped light-emitting portion lies on a first parabola, and at least one light-emitting chip is located at the focal point of the first parabola; and / or along a direction perpendicular to the substrate and parallel to the major axis, at a cross-section of at least one of the plurality of light-emitting chips, the inner wall of the cup-shaped light-emitting portion lies on a second parabola, and at least one light-emitting chip is located at the focal point of the second parabola; wherein the first parabola and the second parabola are adapted to the parabolic surface.

[0007] Furthermore, the light-emitting unit includes a first chip, a second chip, and a third chip arranged sequentially along the long axis. Along a direction perpendicular to the substrate and parallel to the short axis, on the cross-section of the first chip, the inner sidewall of the cup-shaped light-emitting portion is located on a first parabola corresponding to the first chip, the second chip, or the third chip, and the first chip, the second chip, or the third chip is located at the focal point of the first parabola corresponding to it; and / or along a direction perpendicular to the substrate and parallel to the long axis, on the cross-section of the first chip or the third chip, the inner sidewall of the cup-shaped light-emitting portion is located on a second parabola corresponding to the first chip or the third chip, and the first chip or the third chip is located at the focal point of the second parabola corresponding to it.

[0008] Furthermore, the transparent protective layer includes multiple upright isolation slots located between two adjacent light-emitting chips. The LED display module also includes multiple isolation walls filled within the isolation slots, and the isolation walls are non-transparent structures.

[0009] Furthermore, the cup-shaped light-emitting part and the isolation wall enclose the first chip in the first space, the cup-shaped light-emitting part and the isolation wall enclose the second chip in the second space, and the cup-shaped light-emitting part and the isolation wall enclose the third chip in the third space. The volume ratio of the second space to the first space is greater than or equal to 0.6 and less than or equal to 0.8; and / or the volume ratio of the second space to the first space is greater than or equal to 0.6 and less than or equal to 0.8.

[0010] Furthermore, the isolation wall and the transparent protective layer are at the same height.

[0011] Furthermore, the LED display module also includes a functional layer, which is set on the transparent protective layer.

[0012] Furthermore, the functional layer includes a filter layer, which is a multilayer interference film consisting of alternating depositions of high and low refractive index materials.

[0013] Furthermore, the functional layer includes a microlens layer, which contains multiple microlenses, each corresponding to a light-emitting unit.

[0014] Furthermore, the functional layer also includes a grating layer, which is disposed on the surface of the microlens layer away from the transparent protective layer, and the grating layer is made of a subwavelength grating.

[0015] According to another aspect of the present invention, a method for manufacturing an LED display module is provided. The method is used to manufacture the aforementioned LED display module. The method includes: obtaining a substrate of the LED display module; fixing light-emitting units of the LED display module on the substrate; processing a reflective structure of the LED display module on the substrate, wherein a cup-shaped light-emitting portion of the reflective structure is disposed corresponding to a light-emitting unit; and filling the cup-shaped light-emitting portion with a transparent protective layer of the LED display module.

[0016] Furthermore, the process of fixing the light-emitting units of the LED display module on the substrate includes: batch transferring the light-emitting chips of the light-emitting units through a laser lift-off process; and bonding the light-emitting chips and the substrate using conductive adhesive.

[0017] Furthermore, the process of fabricating the reflective structure of the LED display module on the substrate, wherein the cup-shaped light-emitting part of the reflective structure is set in a one-to-one correspondence with the light-emitting unit, includes: forming a reflective structure on the substrate using a UV nanoimprinting process so that the reflective structure and the substrate form a cup-shaped light-emitting part; and depositing a reflective part on the inner wall surface of the reflective structure.

[0018] Furthermore, the process of filling the transparent protective layer of the LED display module into the cup-shaped light-emitting part includes: using a mold to press and fill the UV optical adhesive to form a transparent protective layer, and pressing out an isolation groove; injecting isolation adhesive into the isolation groove to form an isolation wall.

[0019] Furthermore, the LED display module also includes a functional layer, and the manufacturing method further includes: depositing multiple notch filter interference films on a transparent protective layer to form a filter layer; and using a nanoimprinting process to process a microlens layer and a grating layer on the filter layer.

[0020] According to the technical solution of this invention, the LED display module includes a substrate, multiple light-emitting units, a reflective structure, and a transparent protective layer. The multiple light-emitting units are disposed on one side surface of the substrate, and each light-emitting unit includes multiple light-emitting chips. The reflective structure includes a supporting body and a reflective part. The reflective structure and the light-emitting units are disposed on the same side of the substrate. The supporting body has multiple cup-shaped light-emitting parts that are vertically connected and have large openings and small bottoms. The cup-shaped light-emitting parts are arranged one-to-one with the light-emitting units. The cross-sectional shape of the inner sidewall of the cup-shaped light-emitting part is an asymmetrical racetrack shape. The light-emitting units are located at the bottom of the cup-shaped light-emitting parts. The cup-shaped light-emitting parts have mutually perpendicular major and minor axes. The multiple light-emitting chips are arranged along the major axis. The inner sidewall of the cup-shaped light-emitting part forms a reflective part, which is used to emit the light emitted by the light-emitting chips perpendicularly to the substrate. The transparent protective layer is disposed inside the cup-shaped light-emitting part and covers the light-emitting units.

[0021] By directly setting multiple light-emitting units on the substrate and combining them with reflective cup-shaped light-emitting parts, each cup-shaped light-emitting part precisely wraps around each light-emitting unit and forms a closed optical cavity, effectively constraining the lateral propagation path of the light emitted from the light-emitting chip and significantly suppressing light leakage between adjacent pixels. Since the light emitted by the light-emitting chip is a Lambertian distribution that is uniformly diffused in all directions, the inner wall of the cup-shaped light-emitting part is set as an asymmetrical racetrack shape and a reflective part is formed. The cup-shaped light-emitting part has a major axis and a minor axis, which constrain the light emitted from the light-emitting chip in the direction of the major axis and the minor axis, so that the emitted light is emitted in a direction perpendicular to the substrate, further improving the directional reflection efficiency of light in the cavity and reducing scattering loss in non-target directions, thereby greatly improving color purity. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 A front view schematic diagram of an optional embodiment of an LED display module of this application;

[0024] Figure 2 It shows Figure 1 A vertical structural cross-sectional view of the LED display module in the image;

[0025] Figure 3 It shows Figure 1 Isometric side view of the LED display module in the image;

[0026] Figure 4 It shows Figure 2 An enlarged schematic diagram of part B in the diagram;

[0027] Figure 5 This shows a partially enlarged schematic diagram of the LED display module after the light-emitting chip has been installed;

[0028] Figure 6 This shows a partially enlarged cross-sectional view of the LED display module after the reflective structure has been installed;

[0029] Figure 7 This shows a partially enlarged axial view of the LED display module after the reflective structure has been installed;

[0030] Figure 8 This shows a partially enlarged cross-sectional view of the LED display module after the isolation wall has been installed;

[0031] Figure 9 This shows a partially enlarged cross-sectional view of the LED display module after the filter layer has been applied.

[0032] Figure 10 A schematic diagram of the light-emitting path of the light-emitting chip is shown;

[0033] Figure 11 This shows a top-view, partially enlarged schematic diagram of the LED display module after the isolation wall has been installed;

[0034] Figure 12 This shows a partially enlarged axial view of the LED display module after the isolation wall has been installed;

[0035] Figure 13 A flowchart illustrating a method for manufacturing an LED display module according to any optional embodiment of this application is shown.

[0036] The above figures include the following reference numerals:

[0037] 10. Substrate; 20. Light-emitting unit; 21. First chip; 22. Second chip; 23. Third chip; 30. Reflective structure; 31. Reflective part; 32. Support body; 40. Transparent protective layer; 50. Functional layer; 51. Filter layer; 52. Microlens layer; 53. Grating layer; 60. Isolation wall. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0040] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0041] like Figures 1 to 13 As shown, the LED display module for an LED display of this application includes a substrate 10, a light-emitting unit 20, a reflective structure 30, and a transparent protective layer 40. The light-emitting unit 20 is disposed on one side surface of the substrate 10, and the reflective structure 30 is disposed on the same side of the substrate 10 as the light-emitting unit 20, surrounding the light-emitting unit 20 in the middle. The transparent protective layer 40 fills within the reflective structure 30 to cover the light-emitting unit 20 and form a protective layer. In some embodiments, the LED display module further includes a functional layer 50, which is disposed on the transparent protective layer 40 to further improve the optical display effect.

[0042] like Figures 1 to 3 As shown, at least the light-emitting unit 20 and the reflective structure 30 are arranged in an array. Figure 1 As shown in part A of the array arrangement, a plurality of light-emitting units 20 and reflective structures 30 are disposed on the substrate 10. The plurality of light-emitting units 20 are spaced apart, and all reflective structures 30 are simultaneously formed on the substrate 10, with each reflective structure 30 corresponding to a light-emitting unit 20. All reflective structures 30 are connected together, so that the tops of the reflective structures 30 are at the same height without gaps, which facilitates the subsequent processing and forming of the structure.

[0043] like Figures 1 to 9 As shown, the substrate 10 serves to support and protect the light-emitting unit 20. In some embodiments, the substrate 10 is made of glass.

[0044] It should be noted that the substrate 10 of this application is a functional substrate 10, which already has pads, electrodes or adhesive layer structures for chip bonding. Before use, only surface cleaning treatment is required, including plasma cleaning or ultrasonic cleaning, to remove dust and organic impurities, ensure surface cleanliness, and perform drying treatment.

[0045] like Figures 5 to 7 As shown, the reflective structure 30 is formed on the substrate 10. The reflective structure 30 includes a supporting body and a reflective portion 31. The reflective structure 30 and the light-emitting unit 20 are disposed on the same side of the substrate 10. The supporting body has multiple cup-shaped light-emitting portions that are vertically connected and have large openings and small bottoms. The cup-shaped light-emitting portions are arranged one-to-one with the light-emitting units 20. The cross-sectional shape of the inner sidewall of the cup-shaped light-emitting portion is an asymmetrical racetrack shape. The light-emitting unit 20 is located at the bottom of the cup-shaped light-emitting portion. The cup-shaped light-emitting portion has a major axis and a minor axis that are perpendicular to each other. Multiple light-emitting chips are arranged along the major axis. The inner sidewall of the cup-shaped light-emitting portion forms a reflective portion 31, which is used to reflect the light emitted by the light-emitting chip perpendicularly to the substrate 10. Figure 10 As shown in the light trajectory diagram, this improves the directionality of the emitted light, the concentration of brightness, and the efficiency of light energy utilization.

[0046] Specifically, the cross-sectional shape of the light-emitting chip along the direction parallel to the substrate 10 is rectangular. Taking a rectangular chip with a length-to-width ratio of 2:1 as an example, the light-emitting chips are densely arranged in a rectangular array with an ultra-fine pitch of 60μm, but the light emitted is a Lambertian distribution that is evenly diffused in all directions.

[0047] Traditional rotationally symmetric bowl-shaped light emitters have only one degree of curvature freedom, meaning the cross-sectional shape of the inner wall is designed as a rotationally symmetric circle. This makes it impossible to simultaneously apply differentiated optical constraints to the long and short sides of the light-emitting chip: light escapes and causes crosstalk along the long side due to insufficient reflectivity, while excessive reflection along the short side leads to reduced light efficiency, and the circular light-emitting spot crosses boundaries in the rectangular pixel array. In this invention, the cross-sectional shape of the inner wall of the bowl-shaped light-emitting part is designed as an asymmetrical racetrack shape, i.e., a non-rotationally symmetric shape with a major axis and a minor axis. Specifically, the main body of the "racetrack" extends along the major axis, and at least part of both ends of the "racetrack" are arc-shaped. Preferably, the two ends of the "racetrack" are continuous arcs; however, in other embodiments, the two ends of the "racetrack" can also be connected in a sequence of arcs, straight lines, and arcs, with the "straight lines" extending along the minor axis. Furthermore, the curvature of the arcs at both ends of the "racetrack" can be constant (i.e., a segment of the arc) or continuously changing. The inner wall of the cup-shaped light-emitting portion of this application is a parabola. Along a direction perpendicular to the substrate 10 and parallel to the minor axis, in a cross-section at at least one of the plurality of light-emitting chips, the inner wall of the cup-shaped light-emitting portion lies on a first parabola, and at least one light-emitting chip is located at the focal point of the first parabola; and / or along a direction perpendicular to the substrate 10 and parallel to the major axis, in a cross-section at at least one of the plurality of light-emitting chips, the inner wall of the cup-shaped light-emitting portion lies on a second parabola, and at least one light-emitting chip is located at the focal point of the second parabola; wherein the first parabola and the second parabola are adapted to the parabolic surface.

[0048] Specifically, the parabolic surface is obtained by scanning under the original equation of a parabola. In each light-emitting unit, a longitudinal section with a cup-shaped light-emitting portion is made at each light-emitting chip along the minor axis. The edge contour of the cup-shaped light-emitting portion on the longitudinal section is a first parabola, and each light-emitting chip is located at the focus of its corresponding first parabola. When a longitudinal section is made along the major axis, the edge contour of the cup-shaped light-emitting portion on the longitudinal section is a second parabola. Only some light-emitting chips are located at the focus of their corresponding second parabola, while some light-emitting chips are not located at the focus of their corresponding second parabola.

[0049] This asymmetrical racetrack-shaped parabolic bowl-shaped light-emitting part precisely wraps around each light-emitting unit 20 and forms a closed optical cavity, effectively constraining the lateral propagation path of the light emitted from the light-emitting chip and significantly suppressing light leakage between adjacent pixels. Since the light emitted by the light-emitting chip is a Lambertian distribution that is uniformly diffused in all directions, the inner wall of the bowl-shaped light-emitting part is set to an asymmetrical racetrack shape and a reflective part is formed. The bowl-shaped light-emitting part has a major axis and a minor axis, which constrain the light emitted from the light-emitting chip in the direction of the major axis and the minor axis, and emits the light in a direction perpendicular to the substrate 10, further improving the directional reflection efficiency of the light in the cavity and reducing the scattering loss in non-target directions, thereby greatly improving the color purity.

[0050] In some embodiments, such as Figure 3 As shown in section C, the light-emitting unit 20 is soldered to one side surface of the substrate 10. In some embodiments, the light-emitting unit 20 includes a first chip 21, a second chip 22, and a third chip 23 arranged sequentially along the long axis. In some embodiments, these can be red, green, and blue light chips (hereinafter referred to as R / G / B chips). Along a direction perpendicular to the substrate 10 and parallel to the short axis, on the cross-section of the first chip 21, the second chip 22, or the third chip 23, the inner sidewall of the cup-shaped light-emitting portion is located on a first parabola corresponding to the first chip 21, the second chip 22, or the third chip 23, and the first chip 21, the second chip 22, or the third chip 23 is located at the focal point of its corresponding first parabola; and / or along a direction perpendicular to the substrate 10 and parallel to the long axis, on the cross-section of the first chip 21 or the third chip 23, the inner sidewall of the cup-shaped light-emitting portion is located on a second parabola corresponding to the first chip 21 or the third chip 23, and the first chip 21 or the third chip 23 is located at the focal point of its corresponding second parabola. In some embodiments, such as Figure 11 and Figure 12 As shown, the cup-shaped light-emitting part and the isolation wall 60 enclose the first chip 21 in the first space, the cup-shaped light-emitting part and the isolation wall 60 enclose the second chip 22 in the second space, and the cup-shaped light-emitting part and the isolation wall 60 enclose the third chip 23 in the third space. The volume ratio of the first space, the second space, and the third space is 1:(0.6~0.8):1, preferably 1:0.7:1. In other embodiments, it can also be 1:0.6:1, 1:0.8:1, etc.

[0051] like Figure 4 As shown, the transparent protective layer 40 is formed within the space enclosed by the reflective structure 30, that is, the transparent protective layer 40 fills the cup-shaped light-emitting part, which protects the light-emitting unit 20 at the bottom of the cup-shaped light-emitting part and provides a uniform medium for light propagation.

[0052] like Figure 8 As shown, the transparent protective layer 40 has multiple vertically positioned isolation slots located between two adjacent light-emitting chips. Isolation walls 60, which are opaque, are filled within the isolation slots to isolate the light emitted by each light-emitting chip, effectively suppressing light crosstalk and improving color purity and filtering accuracy. Preferably, the isolation walls are black.

[0053] In some embodiments, the top of the partition wall 60 is flush with the top of the transparent protective layer 40 to avoid blocking light.

[0054] like Figure 4 and Figure 9As shown, a functional layer 50 can also be set on the transparent protective layer 40 to improve the display effect.

[0055] In some embodiments, the functional layer 50 includes a filter layer 51 covering the transparent protective layer 40. The filter layer 51 is a multi-band notch filter structure composed of multiple interference films. By alternately depositing high and low refractive index materials, a notch structure for a specific band, namely a strong reflection notch structure, is formed. It has high spectral selectivity, can accurately filter out stray band light, improve color purity and contrast, and the coverage of a certain color gamut. It can also significantly reduce harmful blue light and reduce the impact on the user's eyes.

[0056] In some embodiments, the functional layer 50 further includes a microlens layer 52 for shaping the diverging light emitted from the light-emitting chip or the cup-shaped light-emitting part, thereby achieving light collimation, mixing, and angle control, and improving brightness concentration and color consistency. The microlens layer 52 has a microlens array, with each microlens corresponding to one light-emitting unit 20.

[0057] In some embodiments, the functional layer 50 further includes a grating layer 53 disposed on the microlens layer 52. The grating layer 53 can effectively control the light emission angle and reduce reflection loss, and has functions of light mixing enhancement, angle control optimization and anti-reflection and anti-reflection, improving brightness uniformity and viewing angle consistency, and is suitable for display systems with high brightness, high contrast and high color gamut.

[0058] In one embodiment, the grating layer 53 is made of a subwavelength grating, a nanostructure with a period much smaller than the wavelength of visible light (typically 200-300 nm). Based on the effective medium and Bragg diffraction principle, it possesses ultrathin, wide-angle scattering characteristics. When the grating period is smaller than the incident light wavelength, no higher-order diffraction occurs, and optically it appears as a refractive index gradient layer. The subwavelength grating can significantly reduce the reflectivity at the air-material interface (from approximately 4% to less than 1%), thus providing broadband anti-reflection. The grating's period, depth, and shape can be tuned to control the light emission direction, enabling directional beam emission or expanding the viewing angle, improving viewing angle consistency. Furthermore, the subwavelength grating can suppress interference fringes and ghosting between multilayer films, improving image clarity.

[0059] like Figure 13As shown, this application also provides a manufacturing method for manufacturing the aforementioned LED display module. The manufacturing method includes: step S10: obtaining a substrate 10 for an LED display module for an LED display; step S20: fixing light-emitting units 20 of the LED display module for an LED display on the substrate 10; step S30: processing a reflective structure 30 for the LED display module for an LED display on the substrate 10, wherein the cup-shaped light-emitting portion of the reflective structure 30 corresponds one-to-one with the light-emitting unit 20; step S40: filling the cup-shaped light-emitting portion of the reflective structure 30 with a transparent protective layer 40 for the LED display module for an LED display. The manufacturing method of this application will now be described in conjunction with specific operational methods.

[0060] In some embodiments, step S20 includes steps S21 and S22:

[0061] Step S21: The light-emitting chips of the light-emitting unit 20 are transferred in batches by laser stripping process.

[0062] When multiple light-emitting units 20 are formed on the substrate 10, the R / G / B chips are transferred in large quantities through a laser lift-off process, and the R / G / B chips are transferred from the transfer carrier to the corresponding pad positions on the substrate 10 in one high-precision transfer.

[0063] In one embodiment, the size of a single light-emitting chip is approximately 40×20×10μm, the center-to-center distance between adjacent light-emitting chips is 60μm, and a high-precision coordinate positioning system is used during the transfer process to ensure that the light-emitting chip is precisely aligned with the pads of the substrate 10, with a mounting accuracy better than ±2μm.

[0064] Step S22: Bond the light-emitting chip and the substrate 10 using conductive adhesive.

[0065] Conductive adhesive (such as silver paste) is used to align and bond the light-emitting chip electrodes to the pads of the substrate 10. Electrical connection and structural fixation are achieved through a low-temperature thermosetting process (80-120°C, 10-30 minutes). This method is suitable for substrates 10 made of materials that are not resistant to high temperatures, such as glass. It has advantages such as mild process, low stress, and strong adaptability, which helps to improve module yield and reliability.

[0066] In some embodiments, step S30 includes steps S31 and S32:

[0067] Step S31: Using UV nanoimprinting process, a support body 32 for the reflective structure 30 is formed on the substrate 10. The support body 32 has a plurality of the cup-shaped light-emitting parts.

[0068] Using UV nanoimprinting technology, an asymmetric parabolic cup-shaped light-emitting part is imprinted on the top of the light-emitting chip to collimate and guide the light emitted from the chip, thereby improving the directionality and brightness concentration of the emitted light.

[0069] Unlike traditional rotationally symmetric parabolic surfaces, the bowl-shaped light-emitting portion of this application is parametrically designed. In one embodiment, the profile curve is defined by the following parametric equation:

[0070] The original equation of the parabola: z = x 2 / 4f; x=t; z=2.1875 t 2 +1.4. Where f is the focal length when the R / G / B chip is regarded as the focus, in mm; t is the scanning parameter, the value range of which is determined according to the size of the cup-shaped light-emitting part; x is the lateral coordinate, and z is the height perpendicular to the substrate 10 (i.e., the depth of the cup-shaped light-emitting part).

[0071] The equation represents an upward-opening parabola with an aperture coefficient of 2.1875 and an initial offset of 1.4 mm. By scanning the equation along the curve (related to the R / G / B chip position) within the interval t ∈ [–400 μm, +400 μm], the complete cup-shaped light-emitting section profile curve can be obtained.

[0072] Specifically, the design parameters for the bowl-shaped light-emitting section are as follows:

[0073] Bottom dimensions of the bowl-shaped light-emitting part: minor axis 601μm, major axis 744μm;

[0074] Dimensions of the bowl-shaped light-emitting part: minor axis 771μm, major axis 910μm;

[0075] Height of the cup-shaped light-emitting part: 125μm.

[0076] The sidewall shape of the bowl-shaped light-emitting part is similar to that of a racetrack, and the aperture coefficient is relatively large, which increases the sidewall area of ​​the bowl-shaped light-emitting part.

[0077] The space ratio of the R / G / B chips within the cup-shaped light-emitting section is approximately 1:0.7:1.

[0078] Immediately after imprinting, while the mold remains in place, irradiate with ultraviolet light (wavelength 365nm, intensity 100-300mW / cm²). 2 (30-60 seconds) to fully cure the optical adhesive and form a stable cup-shaped light-emitting part.

[0079] After curing, the mold is removed to obtain a solid bowl-cup array with a complete parabolic profile. The inner wall (effective area) of the bowl-cup-shaped light-emitting part needs to be smooth with a surface roughness Ra < 4nm (mold surface finishing). This structure provides the morphological basis for the subsequent deposition of the reflective part 31.

[0080] Step S32: Deposit a reflective portion 31 on the inner wall surface of the bowl-shaped light-emitting portion of the reflective structure 30.

[0081] A high-reflectivity metal film is deposited on the inner wall of the cup-shaped light-emitting part using PVD (Physical Vapor Deposition) technology, such as electron beam evaporation, to improve light reflection efficiency and prevent light leakage.

[0082] The reflective part 31 is preferably made of aluminum (Al) or a composite film of aluminum + titanium dioxide (Al + TiO2), and the film thickness is controlled within 100nm ± 10nm.

[0083] Preferably, low-temperature annealing (e.g., 80-100°C, 10-20 minutes) is performed to improve the density and adhesion of the film layer of the reflective part 31.

[0084] In another embodiment, IAD (Ion-Assisted Deposition) can be used to introduce ion beam assistance on the basis of PVD to improve the density and adhesion of the reflective part 31.

[0085] In some embodiments, step S40 includes steps S41 to S43:

[0086] Step S41: Use a mold to fill the UV optical adhesive to form a transparent protective layer 40 and press out the isolation groove.

[0087] Using a mold with raised isolation grooves, UV optical adhesive is pressed into the bottom of the cup-shaped light-emitting section, simultaneously pressing out the isolation groove structure. Before pressing, a coordinate alignment system is used to ensure precise alignment between the mold and the light-emitting chip array to avoid structural misalignment. After pressing, UV curing is performed in the bonded state to solidify the adhesive.

[0088] In one embodiment, ultraviolet curing uses a wavelength of 365nm and an intensity of 200mW / cm². 2 Expose the product to ultraviolet light for 30-60 seconds.

[0089] After demolding, a flat, bowl-shaped light-emitting section with a pre-reserved isolation groove structure is obtained, providing a precise channel for the subsequent injection of the isolation wall 60.

[0090] Step S42: Inject isolation adhesive into the isolation tank to form an isolation wall 60.

[0091] A piezoelectric jet dispensing method is used to inject black UV optical adhesive (containing carbon black) into the isolation tank to form a black optical isolation wall 60, which connects to the bottom wall of the cup-shaped light-emitting part. After dispensing, UV curing is performed to stabilize the isolation wall 60.

[0092] In one embodiment, the thickness of the partition wall 60 is 0.1 mm.

[0093] In one embodiment, ultraviolet curing uses a wavelength of 365nm and an intensity of 100-200mW / cm². 2 Expose the product to ultraviolet light for 20-40 seconds.

[0094] It may further include step S43: leveling all the partition walls to a height of 60.

[0095] The partition wall 60 is leveled using a scraper or roller to ensure a uniform height and prevent light blockage. After leveling, a second UV reinforcement treatment is applied to ensure the edges of the partition wall 60 are intact and the structure is stable.

[0096] In some embodiments, the method further includes step S50: processing a functional layer 50 for an LED display module on the transparent protective layer 40.

[0097] In one embodiment, the functional layer 50 includes a filter layer 51, and step S50 includes:

[0098] Step S51: Deposit a multilayer notch filter interference film on the transparent protective layer 40.

[0099] Specifically, an ALD process can be used to deposit a TiO2 / SiO2 multilayer interference film, that is, to form a multilayer interference film by alternating layers of TiO2 and SiO2 oxides, thus forming a three-band notch filter layer 51:

[0100] First notch region (blue stray light): center wavelength is 445nm, bandwidth is 40nm (425-465nm), designed as a 64-layer structure, with a total thickness of about 0.95μm;

[0101] The second notch region (blue-green spurious): the center wavelength is 490nm, the bandwidth is 50nm (465-515nm), and it is designed as an 80-layer structure with a total thickness of about 1.20μm;

[0102] The third notch region (orange-red spurious): with a center wavelength of 590nm and a bandwidth of 60nm (560-620nm), is designed as a 96-layer structure with a total thickness of approximately 1.50μm.

[0103] The principle of the filter layer 51 is as follows: using the multi-layer interference principle (borrowed from the Fabry-Pérot cavity), a strong reflection (notch) structure for a specific wavelength band is formed by alternating deposition of high / low refractive index materials (such as TiO2 / SiO2).

[0104] Specifically, the design formula (center wavelength λ0) is: λ0 = 4n1 d. Where n1 is the refractive index, d is the thickness of the single layer in nm, and the optical path thickness is λ0 / 4nm.

[0105] The bandwidth control logic is as follows: the wider the bandwidth, the more film layers there are; the narrower the bandwidth, the fewer film layers there are; the longer the center wavelength, the thicker the single film layer.

[0106] By precisely controlling the thickness and number of cycles of high / low refractive index materials, a notch filter effect can be achieved for specific wavelengths, thereby improving color purity and BT.2020 color gamut coverage.

[0107] In some embodiments, the functional layer 50 further includes a microlens layer 52 and a grating layer 53, and step S50 further includes:

[0108] Step S52: Fabricate a microlens layer 52 and a grating layer 53 on the filter layer 51.

[0109] A composite structure of a microlens array and a subwavelength grating is formed on the upper surface of the module using a nanoimprinting process. The inner surface of the mold core in this layer has a precision-machined grating structure. The microlenses are used to improve light extraction efficiency and light mixing uniformity, while the grating, based on Bragg diffraction and anti-reflection principles, effectively controls the light extraction angle and reduces reflection loss. Compared to a structure with a single lens layer and uniform light-emitting powder, the composite structure of the microlens layer 52 and the grating layer 53 in this application achieves a wider viewing angle.

[0110] In one embodiment, the grating has a period of 200-280 nm and a height of 200 μm.

[0111] In one embodiment, the microlens has a radius of curvature R = 3.36 mm and a thickness H = 200 μm. The focal length f2 of the microlens is calculated (paraxial approximation): f2 = R / (n2-1). The microlens material is UV optical adhesive with a refractive index n2 of 1.54; therefore, f2 = 3.36 mm / (1.54-1) ≈ 6.22 mm.

[0112] In other embodiments, the LED display module of this application can also be cut into individual pixels and applied to the backlight module, which has a significant effect on improving the theoretical proportion of the BT.2020 color gamut.

[0113] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0114] 1. By directly setting multiple light-emitting units 20 on the substrate 10, combined with non-rotationally symmetric reflective cup-shaped light-emitting parts, each cup-shaped light-emitting part precisely wraps around each light-emitting unit 20 and forms a closed optical cavity, effectively constraining the lateral propagation path of the light emitted from the light-emitting chip and significantly suppressing light leakage between adjacent pixels.

[0115] 2. A reflective part 31 is formed on the inner wall of the cup-shaped light-emitting part to further improve the directional reflection efficiency of light in the cavity and reduce scattering loss in non-target directions, thereby greatly improving color purity;

[0116] 3. A black optical isolation wall 60 is placed in front of adjacent light-emitting chips to completely block light crosstalk between pixels and achieve physical-level light isolation;

[0117] 4. A notch filter layer 51 is deposited above the transparent protective layer 40 to effectively filter out stray wavelengths in the emission spectrum of the light-emitting chip caused by material defects or excitation redundancy, thereby improving color gamut accuracy and color saturation.

[0118] 5. A composite microlens layer 52 and a grating layer 53 are integrally formed on the filter layer 51 to achieve beam focusing and light output uniformity, while the diffraction modulation effect is used to further optimize the angular distribution of the emitted light.

[0119] 6. All the above structures are formed in situ layer by layer on the substrate 10, eliminating the need for traditional multi-layer alignment processes. This fundamentally solves the problems of low yield and optical performance fluctuations caused by multiple structural layers, mismatched thermal expansion coefficients of materials, and accumulated alignment errors, achieving high color purity, high brightness uniformity, and high manufacturing consistency.

[0120] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0121] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0122] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0123] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An LED display module, characterized in that, include: base(10); Multiple light-emitting units (20) are disposed on one side surface of the substrate (10), and each light-emitting unit (20) includes multiple light-emitting chips; The reflective structure (30) includes a supporting body (32) and a reflective part (31). The reflective structure (30) and the light-emitting unit (20) are disposed on the same side of the substrate (10). The supporting body (32) has multiple cup-shaped light-emitting parts that are vertically connected and have large openings and small bottoms. The cup-shaped light-emitting parts are disposed one-to-one with the light-emitting units (20). The cross-sectional shape of the inner sidewall of the cup-shaped light-emitting part is an asymmetrical racetrack shape. The light-emitting unit (20) is located at the bottom of the cup-shaped light-emitting part. The cup-shaped light-emitting part has a long axis and a short axis that are perpendicular to each other. Multiple light-emitting chips are arranged along the long axis. The inner sidewall of the cup-shaped light-emitting part forms the reflective part (31). The reflective part (31) is used to emit the light emitted by the light-emitting chip perpendicular to the substrate (10). A transparent protective layer (40) is disposed inside the cup-shaped light-emitting part and covers the light-emitting unit (20).

2. The LED display module according to claim 1, characterized in that, The inner wall of the bowl-shaped light-emitting part is parabolic. Along a direction perpendicular to the substrate (10) and parallel to the minor axis, at the cross-section of at least one of the plurality of light-emitting chips, the inner wall of the cup-shaped light-emitting portion is located on a first parabola, and the at least one light-emitting chip is located at the focal point of the first parabola. and / or Along a direction perpendicular to the substrate (10) and parallel to the long axis, at the cross-section of at least one of the plurality of light-emitting chips, the inner wall of the cup-shaped light-emitting portion is located on a second parabola, and the at least one light-emitting chip is located at the focal point of the second parabola; The first parabola and the second parabola are adapted to the parabolic surface.

3. The LED display module according to claim 2, characterized in that, The light-emitting unit (20) includes a first chip (21), a second chip (22) and a third chip (23) arranged sequentially along the long axis. Along a direction perpendicular to the substrate (10) and parallel to the minor axis, on the cross-section of the first chip (21), the second chip (22), or the third chip (23), the inner sidewall of the cup-shaped light-emitting portion is located on the first parabola corresponding to the first chip (21), the second chip (22), or the third chip (23), respectively, and the first chip (21), the second chip (22), or the third chip (23) is located at the focal point of the first parabola corresponding to it; and / or Along a direction perpendicular to the substrate (10) and parallel to the long axis, on the cross section of the first chip (21) or the third chip (23), the inner sidewall of the cup-shaped light-emitting part is located on the second parabola corresponding to the first chip (21) or the third chip (23), and the first chip (21) or the third chip (23) is located at the focus of the second parabola corresponding to it.

4. The LED display module according to claim 1, characterized in that, The transparent protective layer (40) includes multiple upright isolation slots, which are located between two adjacent light-emitting chips. The LED display module also includes multiple isolation walls (60), which are filled in the isolation slots and are non-transparent structures.

5. The LED display module according to claim 4, characterized in that, The light-emitting unit (20) includes a first chip (21), a second chip (22), and a third chip (23) arranged sequentially along the long axis. The cup-shaped light-emitting part and the isolation wall (60) enclose the first chip (21) in a first space, the cup-shaped light-emitting part and the isolation wall (60) enclose the second chip (22) in a second space, and the cup-shaped light-emitting part and the isolation wall (60) enclose the third chip (23) in a third space. The volume ratio of the second space to the first space is greater than or equal to 0.6 and less than or equal to 0.8; and / or The volume ratio of the second space to the first space is greater than or equal to 0.6 and less than or equal to 0.

8.

6. The LED display module according to claim 4, characterized in that, The isolation wall (60) has the same height as the transparent protective layer (40).

7. The LED display module according to any one of claims 1 to 6, characterized in that, The LED display module also includes a functional layer (50), which is disposed on the transparent protective layer (40).

8. The LED display module according to claim 7, characterized in that, The functional layer (50) includes a filter layer (51), which is a multilayer interference film with alternating deposition of high and low refractive index materials.

9. The LED display module according to claim 7, characterized in that, The functional layer (50) includes a microlens layer (52), which includes a plurality of microlenses, and the microlenses are arranged in a one-to-one correspondence with the light-emitting unit (20).

10. The LED display module according to claim 9, characterized in that, The functional layer (50) further includes a grating layer (53), which is disposed on the side surface of the microlens layer (52) away from the transparent protective layer (40), and the grating layer (53) is made of a subwavelength grating.

11. A method for manufacturing an LED display module, characterized in that, The manufacturing method is used to manufacture the LED display module according to any one of claims 1 to 10, and the manufacturing method includes: Obtain the substrate (10) of the LED display module; The light-emitting unit (20) of the LED display module is fixed on the substrate (10); The reflective structure (30) of the LED display module is processed on the substrate (10), and the cup-shaped light-emitting part of the reflective structure (30) is arranged in a one-to-one correspondence with the light-emitting unit (20); The transparent protective layer (40) of the LED display module is filled inside the bowl-shaped light-emitting part.

12. The manufacturing method according to claim 11, characterized in that, The process of fixing the light-emitting unit (20) of the LED display module on the substrate (10) includes: The light-emitting chips of the light-emitting unit (20) are transferred in batches using a laser stripping process; The light-emitting chip and the substrate (10) are bonded together using conductive adhesive.

13. The manufacturing method according to claim 11, characterized in that, The process of fabricating the reflective structure (30) of the LED display module on the substrate (10), wherein the cup-shaped light-emitting portion of the reflective structure (30) is configured to correspond one-to-one with the light-emitting unit (20), includes: A support body (32) for the reflective structure (30) is formed on the substrate (10) using a UV nanoimprinting process. The support body (32) has a plurality of cup-shaped light-emitting parts. A reflective portion (31) is deposited on the inner wall surface of the bowl-shaped light-emitting portion.

14. The manufacturing method according to claim 11, characterized in that, The process of filling the transparent protective layer (40) of the LED display module into the cup-shaped light-emitting part includes: The transparent protective layer (40) is formed by filling UV optical adhesive with a mold and pressing out the isolation groove; Injecting a release agent into the isolation groove to form an isolation wall (60).

15. The manufacturing method according to claim 11, characterized in that, The LED display module further includes a functional layer (50), and the manufacturing method further includes: A multilayer notch filter interference film is deposited on the transparent protective layer (40) to form a filter layer (51). A microlens layer (52) and a grating layer (53) are fabricated on the filter layer (51) using a nanoimprinting process.

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