A light source module for miniLED / microLED and a manufacturing method thereof

Abstract

The present invention relates to a light source module for miniLED / microLED and a manufacturing method thereof, wherein the light source module comprises a backplane support, a flexible circuit board attached to the backplane support, and a plurality of LED chips mounted on the flexible circuit board. Diffusing particles are mixed into the encapsulation adhesive layer that entirely covers the LED chip, and the particle size is between 10 and 20 μm, and a reflective pattern coating is provided on the inner surface of the flexible circuit board. The reflective pattern coating is arranged at a portion including the flexible circuit board in the installation gap. The example product of the present invention has the advantage of a thin light source module, and when miniLED is applied, the LED light source can reduce the dark area contrast between the light-emitting points before expanding the light domain, or the pixel primary color light premixing effect when microLED is applied.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor light source devices, and in particular to a light source module applied to miniLED / microLED and a manufacturing method thereof, which can be applied to a miniLED backlight module or a microLED display panel device. Background Art

[0002] MiniLED backlight module and microLED display panel device are the development direction of semiconductor display industry, aiming to provide users with better experience. In the common main structure of MiniLED / MicroLED at present, after the flip-chip LED chip is soldered on the circuit board, it is packaged by silicone, and a single packaged LED chip is installed on the module board to form a light board. Various functional structural films are placed on the FPCA light board to achieve a luminous effect that satisfies the market. In the prior art, the main functional films in MiniLED backlight modules include: 1. Diffuser film, whose main function is to diffuse light, disperse the light emitted by the LED chip to the surroundings, and reduce the display of bright clusters; 2. Anti-red and green film, whose main function is to prevent the passage of red and green wavelengths of light; 3. OD Film (quantum dot film), whose main function is to receive blue wavelengths of light and generate light of different wavelengths after being excited. Among them, the diffuser film that realizes the diffuser function needs to select materials with different haze or diffuser effects according to the MiniLED / microLED arrangement Pitch. Usually, 1 to 4 diffuser films are required, and the thickness of the overall backlight module is relatively thick. The more diffusion function films there are, the higher the module cost and thickness, and the more complicated the module assembly process. Currently, the light diffusion function is mainly achieved by a diffusion plate or diffusion film in a separate area. Depending on the inconsistency of the MiniLED / MicroLED chip arrangement pitch, multiple layers or pieces of diffusion function films are usually used.

[0003] Regarding the prior art of increasing the light diffusion capacity by using diffusion space partitions on both sides of the fluorescent film layer, the invention patent application publication number CN109407395A discloses a MiniLED backlight module, which can disperse the light from the specific light-emitting direction of the LED chip by setting at least one first refractive particle layer between each LED chip and the fluorescent film layer, so that the light can be diffused to a larger area to increase the light-emitting angle. In addition, at least one second refractive particle layer is set on the side of the fluorescent film layer away from the LED chip, which can disperse the light emitted from the fluorescent film layer so that the light can be diffused to a larger area, thereby making the light uniformly emitted from the front of the backlight module. Structurally, the inner and outer surfaces of the fluorescent film layer are each formed with a first refractive particle layer, and the particle distribution density of the first refractive particle layer is less than the particle distribution density of the second refractive particle layer.

[0004] However, in the prior art of similar architecture, it is shown that a refractive / diffusion particle layer is provided on both sides of the fluorescent film layer. After passing through the fluorescent film layer, different colored lights will produce different refractive indices when passing through the refractive particles of the outer refractive particle layer, which affects the light mixing effect. Usually, the light emitted from the front of the LED chip is directional monochromatic light. The gap between the LED chips will produce a dark area effect, and the color light separation aggravates the recognizable contrast of the dark area. Therefore, the particle distribution density outside the fluorescent film layer cannot be reduced. The more refractive / diffusion particles are used, the higher the light loss; and the higher the light loss, the more serious the heating of the backlight module. Therefore, how to reduce the use of diffusion particles and maintain the same level or better light diffusion effect requires continuous research.

[0005] Regarding the prior art that uses an additional component between the substrate and the LED chip to increase the light diffusion capacity, the invention patent application publication number CN111025765A discloses a direct-type backlight device suitable for MiniLED, which includes an array of LED light sources, a PCB substrate, an array of reflective cups, and an optical film. An array of multiple LED light sources is mounted on the PCB substrate. The array of reflective cups reflects a portion of the light distribution of the LED light sources to one side of the display surface of the direct-type backlight device. The optical film is arranged above the reflective cup. An opening is arranged at the bottom of the reflective cup, and a light-transmitting structure is arranged at the connection position between the reflective cups so that light can propagate between the reflective cups through the light-transmitting structure. The array of reflective cups is used to design reflection to increase the light-emitting area of ​​each single LED chip. In the prior art of similar architecture, the opening of the reflective cup must be adapted to the size of the LED chip, and the reflective cup will interfere with the installation of the LED chip on the PCB substrate.

[0006] Regarding the prior art that uses the encapsulation glue that seals the LED chip to increase the light diffusion ability with a high refractive index, the invention patent application publication number CN102197092A discloses a curable organopolysiloxane composition, an optical semiconductor element sealant, and an optical semiconductor device. The organopolysiloxane composition comprises: (A) a methylphenyl alkenyl polysiloxane having at least two alkenyl groups, wherein the diphenylsiloxane unit is at most 5 mol% and at least 20 mol% is composed of phenyl groups, (B) a methylphenyl hydrogen polysiloxane having at least two hydrogen atoms bonded to silicon, wherein the diphenylsiloxane unit is at most 5 mol% and at least 20 mol% is composed of phenyl groups, and (C) a hydrosilylation reaction catalyst. The refractive index for visible light of 589 nm at 25°C is at least 1.5. This type of high-refractive index LED silicone potting glue (high-refractive index silicone) is an optical-grade transparent silicone potting glue with a refractive index of about 1.54. It is made using phenyl technology. This type of high-refractive encapsulation glue used to seal LED chips is quite expensive. When using high-refractive encapsulation glue to form a light source module, its light diffusion efficiency is fixed based on the selection of the refractive index of the glue, and cannot effectively solve the problem of needing to adjust the number of diffusion diaphragms installed due to changes in the installation size or spacing of the LED chips during actual production. Summary of the invention

[0007] The main purpose of the present invention is to provide a light source module for miniLED / microLED, and the main improvement is to solve the problem of increasing the number of diffusion films or diffusion particles required to be installed, which causes the light source module to become thicker and cause light loss and heat generation. In a specific application, even if the pitch of the MiniLED / MicroLED chips is inconsistent, there is no need to adjust the number of multi-layer or multi-piece diffusion functional films used.

[0008] The second main purpose of the present invention is to provide a method for manufacturing a light source module. The main improvement is that compared with the existing technical solutions of using high-cost packaging glue, adding a reflective cup cover, and forming a diffusion / refractive film with a double-sided diffusion zone, it can better achieve low-cost production of a direct-type light source module with a scattered light / mixed light effect, and the obtained product can be specifically applied to a miniLED backlight module or a microLED display panel device.

[0009] The main purpose of the present invention is achieved through the following technical solutions:

[0010] A light source module for miniLED / microLED is proposed, comprising:

[0011] A backplane support member having a stepped frame and a receiving groove in the stepped frame;

[0012] A flexible circuit board partially attached to the receiving groove of the backplane support member;

[0013] A plurality of LED chips are mounted on the inner surface of the flexible circuit board, and an array grid-shaped mounting gap is formed between the LED chips;

[0014] The encapsulation layer is formed on the flexible circuit board in a manner of covering the entire surface, and the LED chip is sealed with light transmittance. The encapsulation layer covers the light-emitting front and side surfaces of the LED chip, and the encapsulation layer is mixed with diffusion particles, and the particle size is between 10 and 20 μm;

[0015] An optical film group structure, the edge of which is disposed on the step frame of the backplane support member;

[0016] Wherein, a reflective pattern coating is provided on the inner surface of the flexible circuit board, and the configuration area of ​​the reflective pattern coating includes the portion of the flexible circuit board in the installation gap.

[0017] By adopting the above basic technical solution and using a specific frame combination, diffusion particles with a particle size of 10 to 20 μm are mixed into the encapsulation glue layer to increase the short-path multi-curved divergent refraction of LED light to the installation gap between LED chips, so as to reduce the number of refractive particle layers or diffusion film plates required to be set on the inner and outer surfaces of the fluorescent film layer, or to reduce the particle distribution density of the diffusion / refractive particles. This is because when the same light diffusion effect is required, the farther away from the LED chip, the higher the number of diffusion particles or particle distribution density required, and when the particle size is less than 10 μm, the phenomenon of direct reflection of light on the particle surface is more important than the multiple refraction effect of light passing through the diffusion particles, which weakens the luminous flux of the multi-curved divergent refraction path; and, in addition, the inner surface of the flexible circuit board is provided with a reflective pattern coating, which serves as a divergent reflection in the installation gap between the LED chips, and can solve the dark area effect of the LED chip array light source at a low cost and has a relatively thin size. When the installation gap between the LED chips changes, the number of diffusion particles mixed in the installation gap also increases naturally, realizing the synchronous dynamic self-adjustment effect of the light diffusion efficiency with the change of the installation size or interval of the LED chip. In addition, under this architecture, the optical film group structure is positioned in the step frame, and the optical film group structure does not have direct thermal contact with the packaging glue layer. It can provide better light-emitting front protection for the packaging glue layer mixed with diffusion particles, and a heat conduction and heat dissipation effect on the back side of the light-emitting light that is stronger than the front side of the light-emitting light, thereby realizing light source protection and back side heat dissipation by first scattering / mixing the light to make it uniform and then adjusting the light domain.

[0018] In a preferred example, the present invention can be further configured as follows: the light source module includes a miniLED backlight module or a microLED display panel device; preferably, the reflective pattern coating includes diffusion wires with a wire diameter ranging from 10 to 100 μm; the reflective pattern coating is in the shape of a staggered mesh, and the reflective pattern coating includes metal silver wires, white glue wires, or a combination thereof according to the material.

[0019] By adopting the above-mentioned preferred features, the diffuse reflection effect of the surface of the reflective pattern coating can be increased by utilizing the diffuse filaments and / or the shape of the reflective pattern coating; by utilizing the material selection of the reflective pattern coating, the coating includes a light-transmitting resin and reflective particles such as white glue and silver powder, so as to enhance the internal diffuse reflection effect by first refraction and then curved surface reflection; preferably, diffuse particles can also be mixed into the reflective pattern coating.

[0020] In a preferred example, the present invention can be further configured as follows: the mass percentage of the mixed diffusion particles in the packaging glue layer is between 9% and 15%, and the diffusion particles include PMMA, nylon, PC, glass particles or a combination of two or more of the foregoing materials.

[0021] By adopting the above-mentioned preferred features and utilizing the specific mass ratio range of the diffusion particles in the encapsulation glue layer, the diffusion particles have the stability of not participating in the reaction in the cross-linking reaction of the silica gel, and the mixing amount of the diffusion particles is controlled to adjust the degree of light diffusion in the side gap of the LED chip to avoid excessive dispersion of the light emission on the front side of the chip; in addition, by utilizing the material selection of the diffusion particles, the refractive index of the diffusion particles can reach 1.5 or above 1.5, and the diffusion particles are a light-dense medium relative to the light-transmitting layer solidified by the curing glue, and the difference in refractive index between the two can be 0.1 or above 0.1, and the light passing through the encapsulation glue layer can produce a multi-refractive light diffusion effect when passing through the diffusion particles.

[0022] In a preferred example, the present invention can be further configured as follows: the precursor of the encapsulation glue layer includes curing glue A and curing glue B, curing glue A includes vinyl siloxane as a main content, and curing glue B includes hydrogenated silicone oil as a main content.

[0023] By adopting the above-mentioned preferred features and utilizing the precursor selection of the encapsulation glue layer, a light-transmitting encapsulation layer having a refractive index greater than that of air and less than that of the diffusion particles is provided. Vinyl siloxane and hydrogen-containing silicone oil can form transparent and colorless silica gel under a cross-linking polymerization reaction. The hydrogen-containing silicone oil can increase the mass fraction of active hydrogen in the cross-linking reaction to improve the tensile strength and hardness of the mixed cured glue, and adjust the light refractive index of the mixed cured glue.

[0024] In a preferred example, the present invention can be further configured as follows: the mass ratio of the curing glue A, the curing glue B, and the diffusion particles is between (1:4:0.5) and (1:10:1.5).

[0025] By adopting the above preferred features, the ratio of curing glue A (vinyl siloxane) to curing glue B (hydrogen-containing silicone oil) is adjusted to 1: 4 to 1: 10 to change the main refractive index of the encapsulation glue layer. When the ratio of curing glue B (hydrogen-containing silicone oil) is increased to reduce the main refractive index, the ratio of diffusion particles is increased to 0.5 to 1.5, and hydrogen-containing silicone oil is used as the main agent of the encapsulation glue layer precursor. Under the conditions of increasing the refractive index difference and increasing the ratio of scattered particles, a lower refractive index encapsulation glue layer precursor can be used. Compared with silicone curing glue using functional groups such as phenyl, a high-cost high-refractive index encapsulation glue layer with a lower cost can achieve the same light diffusion effect.

[0026] In a preferred example, the present invention may be further configured as follows: the thickness of the packaging adhesive layer on the flexible circuit board is between 100 and 160 μm.

[0027] By adopting the above-mentioned preferred features and utilizing the thickness of the encapsulation adhesive layer on the flexible circuit board to define the height of the LED chip mounted on the flexible circuit board, usually the height of the LED chip mounted on the flexible circuit board is not more than 80 μm, and the long side dimension of the LED chip in the miniLED architecture is not more than 200 μm (the long side dimension of the microLED chip is even smaller, approximately below 100 μm). The encapsulation adhesive layer can completely cover the multiple array LED chips on the flexible circuit board, and the thickness portion of the encapsulation adhesive layer on the light-emitting surface of the LED chip is mixed with diffused particles.

[0028] In a preferred example, the present invention can be further configured as follows: the backplane support member includes a metal frame bottom plate and a plastic frame fixed to the metal frame bottom plate and surrounding the periphery of the metal frame bottom plate, and the plastic frame provides the step frame.

[0029] By adopting the above preferred features, the backplane support uses the metal frame bottom plate to dissipate heat on the back side of the chip bonding, and avoids the backplane support from conducting heat to the various light processing layers of the optical film group structure through the glue frame, for example, specifically reducing the emission and escape of quantum dots in the optical film group structure in miniLED applications. The step frame is provided by the glue frame, which increases the positioning margin of the optical film group structure.

[0030] In a preferred example, the present invention can be further configured as follows: when the light source module is a miniLED backlight module, the LED chip is directly bonded to the flexible circuit board in a flip chip COF manner; preferably, the optical film group structure includes a filter film, an excitation film, and a brightening film from the inside to the outside, and the thickness of the encapsulation layer is less than the height difference between the bottom of the step frame and the step frame, so that the encapsulation layer and the filter film maintain a non-contact light-emitting gap.

[0031] By adopting the above preferred features, the LED chip is directly bonded to the flexible circuit board in a flip chip COF manner, and a large number of LED chips are transferred to the flexible circuit board. In this architecture, the LED chip and the flexible circuit board are welded with protruding electrodes, and the bottom surface of the LED chip bonded in the flip chip COF will be higher than the coating height of the reflective pattern coating on the flexible circuit board. Therefore, the setting of the reflective pattern coating will not have a harmful effect on the installation of the LED chip, nor will it interfere with the installation of the LED chip. Preferably, the thickness of the encapsulation glue layer is smaller than the bottom height difference between the step frame and the step frame, so that a non-contact luminous gap is generated between the encapsulation glue layer and the filter film, forming a structure in which the luminous front side does not conduct heat, and the heat generated by the LED chip will not be directly conducted from the luminous front side to the various light processing film layers of the optical film group structure.

[0032] In a preferred example, the present invention can be further configured as follows: the light source module further includes a shading sheet, the periphery of which is installed above the step frame of the back panel support, and the opening of the shading sheet is located on the optical film group structure; preferably, the filter film includes an anti-red and green film, and the excitation film includes a quantum dot film.

[0033] By adopting the above preferred features, the shading sheet is installed to cover the luminous parts of the four edges of the backplane support. Preferably, the anti-red and green film included in the filter film and the quantum dot film included in the excitation film are used to select a blue light LED chip, and the anti-red and green film is used to filter out the red and green light after the light is diffused, and then the quantum dot film is used to excite the blue light into white light or white mixed light to improve the display effect, and the brightness enhancement film is used to change the direction of the emitted light to upward (towards the direction away from the light-emitting surface of the LED chip), and the overall light source has uniform intensity and light color uniformity of surface light emission.

[0034] The second main purpose of the present invention is achieved through the following technical solutions:

[0035] A manufacturing method is proposed for making a light source module according to any of the technical solutions described above, wherein the reflective pattern coating is applied to the flexible circuit board after the flexible circuit board is formed and before the LED chip is installed; preferably, in the step of forming the encapsulation glue layer, when the precursor of the encapsulation glue layer includes curing glue A and curing glue B, the encapsulation glue is stirred with the assistance of a catalyst and an adhesive to form the encapsulation glue, and diffusion particles are added after mixing. After mixing and stirring, the front side of the flexible circuit board is coated with glue once or multiple times in the X and Y directions to form the encapsulation glue layer covering the LED chip; preferably, in the process of coating to form the encapsulation glue layer, the encapsulation glue layer also fills the installation gap and contacts the reflective pattern coating; preferably, the printing method of the reflective pattern coating includes screen printing, and the material used for the reflective pattern coating includes white oil or silver paste.

[0036] By adopting the above technical solution, using the coating setting method and formation sequence of the reflective pattern coating, it is not necessary to change the circuit layout of the flexible circuit board and not interfere with the installation of the LED chip on the flexible circuit board. The installation gap formed between the LED chips can have diffuse light refracted by the diffusion particles and diffusely reflect light through the reflective pattern coating to eliminate or reduce the dark area effect between the LED chips. Preferably, by defining the steps of forming the encapsulation glue layer, first mix the curing glue A and the curing glue B, then add the stirring catalyst and the adhesive, and then add the diffusion particles after mixing. The step-by-step and orderly addition and mixing avoids the bubbling of the encapsulation glue layer precursor. The use of one-time glue coating or multiple glue coatings including X-direction and Y-direction depends on the purpose of avoiding the air traps encapsulated by air or the gaps filled with loose glue to form the installation gaps between the LED chips. Preferably, the reflective pattern coating formed by screen printing can have more diverse patterns and designs, and the materials and proportions of the reflective pattern coating have design flexibility. Conventional materials and processes that are not used to make flexible circuit boards can be selected, and the thickness of the reflective pattern coating can also be adjusted.

[0037] In summary, the examples of the present invention include at least one of the following beneficial technical effects that contribute to the prior art:

[0038] 1. Diffusion particles are mixed into the encapsulation layer. The light emitted by the chip also passes through the round or elliptical surface of the particles in the encapsulation layer. The light undergoes multiple curved surface reflections and refractions to achieve the purpose of scattering light in the installation gap between chips, and then diffusely reflects with the reflective pattern coating;

[0039] 2. Compared with the existing technical means of light diffusion, the structure of the light source module used in miniLED / microLED is thinned and concentrated, the manufacturing process of the reflection mechanism is simplified, and the cost of the encapsulation layer is reduced;

[0040] 3. Compared with the light source module structure of the existing technology, it can provide a solution with better light effect adjustment and matching. The light source module can be applied to mobile phones, tablets, wearables, vehicles and flexible displays and has its own astigmatism effect;

[0041] 4. Provide more solutions for miniLED / microLED flexible display. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagrams showing the cross-sectional structures of light source modules of some preferred embodiments of the present invention;

[0043] Figure 2 A partial cross-sectional schematic diagram of a light source module of some preferred embodiments of the present invention is shown;

[0044] Figure 3 The light source modules of some preferred embodiments of the present invention are shown in FIG. Figure 2 A local enlarged schematic diagram in FIG.

[0045] Figure 4 and Figure 5 Schematic diagram of the inner surface of the flexible circuit board in the installation gap in some preferred embodiments of the present invention is shown ( Figure 4 An example of a hexagonal arrangement of LED chips. Figure 5 (Another example of a square arrangement of LED chips).

[0046] Figure numerals: 10, back panel support; 11, step frame; 12, accommodating groove; 13, metal frame bottom plate; 14, rubber frame; 20, flexible circuit board; 21, fixed rubber layer; 22, extension section; 30, LED chip; 31, installation gap; 32, bonding electrode; 40, packaging rubber layer; 41, diffusion particles; 50, optical film group structure; 51, filter film; 52, excitation film; 53, brightening film; 60, reflective pattern coating; 61, diffusion wire; 70, shading film. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments for understanding the inventive concept of the present invention, and cannot represent all the embodiments, nor are they interpreted as the only embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field on the premise of understanding the inventive concept of the present invention are within the scope of protection of the present invention.

[0048] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0049] In order to facilitate understanding of the technical solution of the present invention, a light source module applied to miniLED / microLED and a manufacturing method thereof of the present invention are further described and explained in detail in the following embodiments, but are not intended to limit the protection scope of the present invention.

[0050] Figure 1 Schematic diagrams showing the cross-sectional structures of light source modules of some preferred embodiments of the present invention; Figure 2 A partial cross-sectional schematic diagram of a light source module of some preferred embodiments of the present invention is shown; Figure 3 The light source modules of some preferred embodiments of the present invention are shown in FIG. Figure 2 A local enlarged schematic diagram in FIG. Figure 4 and Figure 5 Schematic diagrams showing the inner surface of a flexible circuit board in an installation gap in some preferred embodiments of the present invention where a reflective pattern coating is disposed. Figures 1 to 5 It does not represent only one embodiment. Figures 1 to 5 Any one figure or combination of figures does not represent individual embodiments. Figures 1 to 5 Only the common parts of the multiple embodiments are illustrated, and the different or distinguished parts are described in words or presented in comparison with the drawings, for example Figure 4 , Figure 5 The LED chips in different examples are shown to be arranged in hexagonal and tetragonal arrangements. Basically, different chip arrangements cannot coexist in the same embodiment; however, the technical solution of the present application is mainly to effectively improve the dark area effect of the installation gap between chips. When the arrangement method is changed and the same embodiment exists, the dark area effect is still not obvious. Therefore, in order to improve the problem of insufficient local light emission, hexagonal and tetragonal arrangements can appear at the same time in the extreme combination of chip mass transfer. Therefore, based on the characteristics of the industry and the essence of the technology, it should be correctly and reasonably understood and judged whether the individual technical features described below or any combination of them can be characterized in the same embodiment, or whether multiple technical features that are mutually exclusive in essence can only be characterized in different variations. In some preferred examples, the light source module includes a miniLED backlight module or a microLED display panel device.

[0051] Reference Figures 1 to 3 , a light source module applied to miniLED / microLED disclosed in some embodiments of the present invention, comprising:

[0052] The backplane support member 10 has a stepped frame 11 and a receiving groove 12 in the stepped frame 11; the backplane support member 10 is used to support the flexible circuit board 20 and the LED chip 30 and provide a back heat dissipation path for the LED chip 30;

[0053] The flexible circuit board 20 is partially attached to the receiving groove 12 of the backplane support member 10; the flexible circuit board 20 functions as an electrical transmission of the LED chip 30;

[0054] A plurality of LED chips 30 are mounted on the inner surface of the flexible circuit board 20, and an array grid-shaped mounting gap 31 is formed between the LED chips 30; the LED chips 30 arranged in an array function as a flat or curved light source;

[0055] The encapsulation layer 40 is formed on the flexible circuit board 20 in a manner of covering the entire surface, and seals the LED chip 30 with light transmittance. The encapsulation layer 40 covers the light-emitting front and side surfaces of the LED chip 30. The encapsulation layer 40 contains diffusion particles 41, and the particle size is between 10 and 20 μm. The encapsulation layer 40 functions as a protection for the LED chip 30. The diffusion particles 41 are used to enhance the local light diffusion between the LED chips 30 by multi-bending and refracting part but not all of the diffused light based on the light diffusion of the transparent material body of the encapsulation layer 40.

[0056] The optical film group structure 50, whose edge is disposed on the step frame 11 of the back panel support member 10; the optical film group structure 50 is used for post-processing the angle, direction or light domain of the emitted light, etc. after the light is diffused;

[0057] Among them, a reflective pattern coating 60 is provided on the inner surface of the flexible circuit board 20, and the configuration area of ​​the reflective pattern coating 60 includes the portion of the flexible circuit board 20 in the installation gap 31; the reflective pattern coating 60 is used to diffusely reflect the diffused light between the LED chips 30.

[0058] The implementation principle of this embodiment is as follows: under a specific frame combination, diffusion particles 41 with a particle size of 10 to 20 μm are mixed into the packaging glue layer 40 to increase the short-path multi-curved divergent refraction of the LED light to the installation gap 31 between the LED chips 30, so as to reduce the number of refractive particle layers or diffusion film plates required to be set on the inner and outer surfaces of the fluorescent film layer, or to reduce the particle distribution density of the diffusion / refractive particles. This is because when the same light diffusion effect is required, the farther the distance from the LED chip 30 is, the higher the number of diffusion particles 41 or the particle distribution density required, and when the particle size is less than 10 μm, the phenomenon of direct reflection of light on the particle surface is more serious than the multiple refraction effect of light passing through the diffusion particles 41, which weakens the influence on the luminous flux of the multi-curved divergent refraction path; and, in addition, the inner surface of the flexible circuit board 20 is provided with a reflective pattern coating 60, which serves as a divergent reflection in the installation gap 31 between the LED chips 30, can solve the dark area effect of the LED chip 30 array light source at a low cost and has a relatively thin size. In addition, under this architecture, the optical film group structure 50 is positioned in the step frame 11, and the optical film group structure 50 does not have direct thermal contact with the packaging glue layer 40. It can provide better light-emitting front protection and a heat conduction and heat dissipation effect on the back side of the light-emitting layer 40 that is stronger than the light-emitting front side, thereby realizing the light source protection and back side heat dissipation of the light source by first scattering / mixing the light to make it uniform and then adjusting the light domain.

[0059] Regarding the specific structure of the backplane support 10, in some preferred examples, the backplane support 10 is used to reinforce and support the flexible circuit board 20, and can be a heat dissipation base. More specifically, the backplane support 10 includes a metal frame bottom plate 13 and a glue frame 14 fixed to the metal frame bottom plate 13 and surrounding the periphery of the metal frame bottom plate 13, and the glue frame 14 provides the step frame 11. The material of the metal frame bottom plate 13 may include copper, iron and other metals with high thermal conductivity. The glue frame 14 can be a white glue frame 14 bracket to increase the light reflection characteristics that do not absorb light and do not generate heat. Therefore, the backplane support 10 uses the metal frame bottom plate 13 to dissipate heat on the back side of the chip bonding, and avoids the backplane support 10 from conducting heat to the various light processing layers of the optical film group structure 50 through the glue frame 14, for example, specifically in miniLED applications, reducing the heat dissipation and escape of quantum dots in the optical film group structure 50. The step frame 11 is provided by the plastic frame 14 , which increases the positioning margin of the optical film group structure 50 .

[0060] Regarding the specific structure and installation of the flexible circuit board 20 (FPC), in some preferred examples, the flexible circuit board 20 is fixed to the backplane support 10 (specifically, Figure 3 As shown), the fixed adhesive layer 21 may be a double-sided adhesive film having adhesiveness on both sides. Figure 1The flexible circuit board 20 may also have an extended section 22 located outside the backplane support 10 as an external electrical connection for the LED chip 30 .

[0061] Regarding the specific structure and installation of the LED chip 30, in some preferred examples, when the light source module is a miniLED backlight module, the LED chip 30 is directly bonded to the flexible circuit board 20 in a flip chip COF (Chip On Film) manner; for example, in the growth process of the LED chip 30, the bonding electrode 32 is formed on the upper surface of the chip, and the chip is flipped after singulation so that the bonding electrode 32 is soldered to the circuit contact of the flexible circuit board 20 (specifically, Figure 3 As shown). The installation gap 31 between the LED chips 30 is a relatively dark area, and the LED chip 30 has the semiconductor property of electroluminescence. The LED chip 30 can emit monochromatic light in the application of the miniLED backlight module, preferably blue light; the LED chip 30 can be a pixel unit of multi-color mixed light in the application of the microLED display panel device, which can mix the red light, green light, and blue light in a short path, and each pixel includes a dense arrangement of LED chips 30 of various three primary colors. Therefore, the LED chip 30 is directly bonded to the flexible circuit board 20 in a flip chip COF manner to transfer a large number of LED chips 30 to the flexible circuit board 20. In this architecture, the LED chip 30 and the flexible circuit board 20 are welded with a protruding bonding electrode 32. The bottom surface of the LED chip 30 bonded in the flip chip COF will be higher than the coating height of the reflective pattern coating 60 on the flexible circuit board 20. Therefore, the setting of the reflective pattern coating 60 will not have a harmful effect on the installation of the LED chip 30, nor will it interfere with the installation of the LED chip 30.

[0062] In other preferred examples, the LED chip 30 can also be installed with the front side facing up in the COB wafer process. The front side in the wafer process here refers to the surface of film deposition or epitaxial growth in the wafer form, which can be electrically connected to the flexible circuit board 20 by wire bonding or vias.

[0063] See also Figure 4 , Figure 5 The arrangement of the LED chips 30 on the flexible circuit board 20 can be a hexagonal arrangement, a quadrilateral arrangement, or a hexagonal arrangement and a quadrilateral arrangement in different areas. The hexagonal arrangement means that six LED chips 30 are equally spaced and arranged in a circle centered on any LED chip 30 of the same light color that is not located at the edge, forming a regular hexagon. The quadrilateral arrangement means that four LED chips 30 are equally spaced and arranged in a circle centered on any LED chip 30 of the same light color that is not located at the edge, forming a square.

[0064] Regarding the embodiment and formation of the main transparent glue material of the encapsulation glue layer 40, in some preferred examples, the precursor of the encapsulation glue layer 40 includes curing glue A and curing glue B, curing glue A includes vinyl siloxane as a main content, and curing glue B includes hydrogenated silicone oil as a main content. Therefore, by selecting the precursor of the encapsulation glue layer 40, a light-transmitting encapsulation layer with a refractive index greater than that of air and less than that of the diffusion particles 41 is provided, and vinyl siloxane and hydrogenated silicone oil can form transparent and colorless silica gel under cross-linking polymerization reaction, and hydrogenated silicone oil can increase the mass fraction of active hydrogen in the cross-linking reaction to improve the tensile strength and hardness of the curing glue after mixing, and adjust the light refractive index of the curing glue after mixing.

[0065] Regarding the specific materials and proportions of the diffusion particles 41 mixed into the encapsulation glue layer 40, in some preferred examples, the mass percentage of the diffusion particles 41 mixed into the encapsulation glue layer 40 is between 9% and 15%, and the diffusion particles 41 include PMMA, nylon, PC, glass particles, or a combination of two or more of the above materials. Therefore, by utilizing the specific mass ratio range of the diffusion particles 41 in the encapsulation glue layer 40, the diffusion particles 41 have the stability of not participating in the reaction in the cross-linking reaction of the silicone, and the mixing amount of the diffusion particles 41 is controlled to adjust the light diffusion degree in the side gap of the LED chip 30 to avoid excessive dispersion of the light emission on the front side of the chip; in addition, by utilizing the material selection of the diffusion particles 41, the refractive index of the diffusion particles 41 can reach 1.5 or above 1.5, and the diffusion particles 41 are optically dense media relative to the light-transmitting layer solidified by the curing glue, and the difference in refractive index between the two can be 0.1 or above 0.1, and the light passing through the encapsulation glue layer 40 can produce a multi-refractive light diffusion effect when passing through the diffusion particles 41.

[0066] Regarding the specific ratio range of the diffusion particles 41 mixed into the encapsulation glue layer 40, in some preferred examples, the mass ratio of the curing glue A, the curing glue B and the diffusion particles 41 is between (1: 4: 0.5) and (1: 10: 1.5). Therefore, the ratio of the curing glue A (vinyl siloxane) to the curing glue B (hydrogen-containing silicone oil) is adjusted between 1: 4 and 1: 10 to change the main refractive index of the encapsulation glue layer 40. When the ratio of the curing glue B (hydrogen-containing silicone oil) is increased to reduce the main refractive index, the ratio of the diffusion particles 41 is increased to 0.5 to 1.5, and the hydrogen-containing silicone oil is used as the main agent of the precursor of the encapsulation glue layer 40. Under the conditions of increasing the refractive index difference and increasing the proportion of scattered particles, a lower refractive index encapsulation glue layer 40 precursor can be used. Compared with using silicone-cured glue with functional groups such as phenyl, a high-refractive index encapsulation glue layer 40 with a lower cost can achieve the same light diffusion effect as a high-cost high-refractive index encapsulation glue layer 40.

[0067] In some preferred examples, the thickness of the encapsulation layer 40 on the flexible circuit board 20 is between 100 and 160 μm. Therefore, based on the thickness of the encapsulation layer 40 on the flexible circuit board 20, the height of the LED chip 30 mounted on the flexible circuit board 20 is usually not more than 80 μm, and the long side dimension of the LED chip 30 in the miniLED architecture is not more than 200 μm (the long side dimension of the microLED chip is smaller, about 100 μm or less). The encapsulation layer 40 can completely cover the multiple array LED chips 30 on the flexible circuit board 20, and the thickness of the encapsulation layer 40 on the light-emitting surface of the LED chip 30 is mixed with diffusion particles 41.

[0068] Regarding the specific structure and installation of the optical film group structure 50, in some preferred examples, the optical film group structure 50 includes a filter film 51, an excitation film 52, and a brightness enhancement film 53 from the inside to the outside, the filter film 51 is used to filter unexpected stray light, the excitation film 52 is used to expand the light domain of the emitted light, and one or more layers of brightness enhancement film 53 are used to change or correct the direction of the light, and the thickness of the encapsulation glue layer 40 is less than the bottom height difference between the step frame 11 and the step frame 11, so that the encapsulation glue layer 40 and the filter film 51 maintain a non-contact light-emitting gap. Therefore, by using the thickness of the encapsulation glue layer 40 being less than the bottom height difference between the step frame 11 and the step frame 11, a non-contact light-emitting gap is generated between the encapsulation glue layer 40 and the filter film 51, forming a structure in which the light-emitting front side does not conduct heat, and the heat generated by the LED chip 30 will not be directly conducted from the light-emitting front side to the various light-processing film layers of the optical film group structure 50. Preferably, the filter film 51 includes a red-green anti-film, and the excitation film 52 includes a quantum dot film. In a specific example, a gap is left between the optical film group structure 50 and the packaging glue layer 40, and the optical film group structure 50 closes the opening of the receiving groove 12 to avoid compressing the packaging glue layer 40 mixed with the diffusion particles 41.

[0069] In some preferred examples, the light source module may further include a shading sheet 70, the periphery of which is installed above the step frame 11 of the back panel support 10, and the opening of the shading sheet 70 is located on the optical film group structure 50. Therefore, by installing the shading sheet 70, the luminous parts of the four edges of the back panel support 10 are shielded. Preferably, the anti-red and green film included in the filter film 51 and the quantum dot film included in the excitation film 52 are used to select a blue light LED chip 30, and the anti-red and green film is used to filter out the red and green light after the light is diffused, and then the quantum dot film is used to excite the blue light into white light or white mixed light to improve the display effect, and the brightness enhancement film 53 is used to change the direction of the emitted light to be upward (towards the direction away from the light-emitting surface of the LED chip 30), and the overall light source has uniform intensity of surface light emission and uniform light color.

[0070] Regarding the specific structure and configuration of the reflective pattern coating 60, in some preferred examples, refer to Figure 4 , Figure 5 The reflective pattern coating 60 includes a diffusion wire 61, the wire diameter of which is between 10 and 100 μm; the reflective pattern coating 60 is in the shape of a staggered mesh, and the reflective pattern coating 60 includes metal silver wire, white glue wire, or a combination thereof according to the material. Therefore, the diffuser wire 61 or / and its shape included in the reflective pattern coating 60 are used to increase the diffuse reflection effect on the surface of the reflective pattern coating 60; the material selection of the reflective pattern coating 60 includes a light-transmitting resin and reflective particles such as white glue and silver powder in the coating, so as to enhance the internal diffuse reflection effect by first refraction and then curved surface reflection; preferably, the diffuser particles 41 can also be mixed into the reflective pattern coating 60.

[0071] In addition, some other embodiments of the present invention disclose a manufacturing method for making a light source module according to any of the technical solutions described above, wherein the reflective pattern coating 60 is printed on the flexible circuit board 20 after the flexible circuit board 20 is formed and before the LED chip 30 is installed.

[0072] The implementation principle of this embodiment is: by utilizing the coating setting method and formation sequence of the reflective pattern coating 60, there is no need to change the circuit layout of the flexible circuit board 20 and does not interfere with the installation of the LED chip 30 on the flexible circuit board 20. The installation gap 31 formed between the LED chips 30 can have diffuse light refracted by the diffusion particles 41 and diffusely reflected by the reflective pattern coating 60 to eliminate or reduce the dark area effect between the LED chips 30.

[0073] Regarding the detailed formation steps of the encapsulation glue layer 40, in some preferred examples, in the step of forming the encapsulation glue layer 40, when the precursor of the encapsulation glue layer 40 includes curing glue A and curing glue B, the encapsulation glue is formed by stirring with the assistance of a catalyst and an adhesive, and the diffusion particles 41 are added after mixing. After mixing and stirring, the front side is coated with glue on the flexible circuit board 20 once or multiple times in the X direction and the Y direction to form the encapsulation glue layer 40 covering the LED chip 30; preferably, in the process of coating to form the encapsulation glue layer 40, the encapsulation glue layer 40 also fills the installation gap 31 and contacts the reflective pattern coating 60; preferably, the printing method of the reflective pattern coating 60 includes screen printing, and the material used for the reflective pattern coating 60 includes white oil or silver paste.

[0074] According to the step definition of forming the encapsulation glue layer 40, the curing glue A and the curing glue B are first mixed, and then the stirring catalyst and the adhesive are added. After mixing, the diffusion particles 41 are added. The step-by-step and orderly addition and mixing avoids the bubbling of the precursor of the encapsulation glue layer 40. The use of one-time glue coating or multiple glue coatings including X-direction and Y-direction is based on the purpose of avoiding the air traps encapsulated by air or the gaps filled with loose glue to form the installation gap 31 between the LED chips 30. Preferably, the reflective pattern coating 60 formed by screen printing can have more diverse patterns and designs. The material and ratio of the reflective pattern coating 60 have design flexibility. Conventional materials and processes that are not used to make the flexible circuit board 20 can be selected, and the thickness of the reflective pattern coating 60 can also be adjusted.

[0075] In summary, when the diffusion particles 41 are mixed and stirred with the packaging glue to form an integrated whole, the purpose of packaging and light dispersion is achieved after the entire surface is coated with glue. After the entire surface is coated with glue, there will also be a glue layer with this function between the chips, and the four sides of the chip will also emit light. When matched with the FPC flexible circuit board with white oil / silver printed on the surface, it can increase light reflection, increase light utilization, reduce light loss, increase module brightness, and achieve a brighter and better mixed light effect. Therefore, the light source module proposed in each example of the present invention can directly make part or all of the functions of the diffusion plate directly in the packaging glue of the chip, and the ratio can be adjusted according to the actual use effect, and the light dispersion effect can be satisfied through the glue layer, saving about 0.5mm of the overall module thickness. When the arrangement pitch Pitch of the LED chips 30 in the miniLED / microLED architecture increases, more diffusion particles 41 are mixed into the installation gap 31 between the LED chips 30, thereby improving the dark area effect between the LED chips 30 in a positively correlated relationship. This can improve the problem of the need to use a multi-layer diffusion functional film to adapt and adjust the module so that the module is thick or thin, or the module needs to be designed with a thicker adjustable diffusion functional film.

[0076] The embodiments of this specific implementation method are all preferred embodiments for facilitating the understanding or implementation of the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention. All equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A light source module applied to miniLED / microLED, characterized in that: include: A backboard support member (10) having a step frame (11) and a receiving groove (12) in the step frame (11); A flexible circuit board (20) is partially attached to the receiving groove (12) of the backplane support member (10); A plurality of LED chips (30) are mounted on the inner surface of the flexible circuit board (20), and array grid-shaped mounting gaps (31) are formed between the LED chips (30); The encapsulation adhesive layer (40) is formed on the flexible circuit board (20) in a manner of covering the entire surface, and seals the LED chip (30) with light transmittance. The encapsulation adhesive layer (40) covers the light-emitting front and side surfaces of the LED chip (30). Diffusion particles (41) are mixed into the encapsulation adhesive layer (40), and the particle size is between 10 and 20 μm. An optical film group structure (50), the edge of which is arranged on the step frame (11) of the back panel support (10); The inner surface of the flexible circuit board (20) is provided with a reflective pattern coating (60), and the configuration area of ​​the reflective pattern coating (60) includes the portion of the flexible circuit board (20) in the installation gap (31); The mass percentage of the mixed diffusion particles (41) in the packaging glue layer (40) is between 9% and 15%, and the diffusion particles (41) include one or more combinations of PMMA, nylon, PC, and glass particles according to the material. The precursor of the encapsulation glue layer (40) includes curing glue A and curing glue B, wherein the curing glue A includes vinyl siloxane and the curing glue B includes hydrogen-containing silicone oil; The mass ratio of the curing glue A, the curing glue B and the diffusion particles (41) is between (1:4:0.5) and (1:10:1.5). The ratio of the curing glue A to the curing glue B is adjusted between 1:4 and 1:10 to change the main refractive index of the packaging glue layer. When the ratio of the curing glue B is increased to reduce the main refractive index, the ratio of the diffusion particles is increased simultaneously to 0.5 to 1.5, and hydrogen-containing silicone oil is used as the main agent of the packaging glue layer precursor.

2. The light source module according to claim 1, characterized in that: The light source module includes a mini LED backlight module or a micro LED display panel device.

3. The light source module according to claim 1, characterized in that: The thickness of the packaging adhesive layer (40) on the flexible circuit board (20) is between 100 and 160 μm.

4. The light source module according to claim 1, characterized in that: The backplane support member (10) comprises a metal frame bottom plate (13) and a plastic frame (14) fixed to the metal frame bottom plate (13) and surrounding the periphery of the metal frame bottom plate (13), wherein the plastic frame (14) provides the step frame (11).

5. The light source module according to any one of claims 1 to 4, characterized in that: When the light source module is a miniLED backlight module, the LED chip (30) is directly bonded to the flexible circuit board (20) in a flip chip COF manner.

6. The light source module according to claim 5, characterized in that: The optical film group structure (50) comprises, from the inside to the outside, a filter film (51), an excitation film (52), and a brightness enhancement film (53), and the thickness of the packaging glue layer (40) is less than the height difference between the bottoms of the step frames (11) and the step frames (11), so that the packaging glue layer (40) and the filter film (51) maintain a non-contact light-emitting gap.

7. The light source module according to claim 5, characterized in that: It also includes a shading sheet (70), the periphery of which is installed above the step frame (11) of the back panel support (10), and the opening of the shading sheet (70) is located on the optical film group structure (50).

8. The light source module according to claim 6, characterized in that: The filter film (51) comprises a red-green anti-film, and the excitation film (52) comprises a quantum dot film.

9. A manufacturing method, characterized in that: Used to manufacture a light source module for miniLED / microLED as described in any one of claims 1 to 8, the reflective pattern coating (60) is printed on the flexible circuit board (20) after the flexible circuit board (20) is formed and before the LED chip (30) is installed.

10. The manufacturing method according to claim 9, characterized in that: In the step of forming the encapsulation glue layer (40), when the precursor of the encapsulation glue layer (40) includes curing glue A and curing glue B, the encapsulation glue is stirred with the assistance of a catalyst and an adhesive to form the encapsulation glue, and then the diffusion particles (41) are added after mixing. After mixing and stirring, the front side of the flexible circuit board (20) is coated with glue once or multiple times in the X direction and the Y direction to form the encapsulation glue layer (40) covering the LED chip (30).

11. The manufacturing method according to claim 10, characterized in that: In the process of coating to form the packaging adhesive layer (40), the packaging adhesive layer (40) also fills the installation gap (31) and contacts the reflective pattern coating (60); the coating method of the reflective pattern coating (60) includes screen printing, and the material used for the reflective pattern coating (60) includes white oil or silver paste.

12. A display device, characterized in that: It comprises a light source module applied to miniLED / microLED as described in any one of claims 1-8.

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