Processing method of circuit substrate of display module and processing method of display module

Abstract

The invention provides a processing method of a circuit substrate of a display module, comprising the following steps: providing a first substrate for the display module, the first substrate having a first surface, the first surface being provided with a plurality of pads for welding LED chips; a photosensitive solder resist ink covering layer is formed on the first surface through a spin coating process, the photosensitive solder resist ink covering layer covers the first substrate and a bonding pad on the first substrate, and the surface, away from the bonding pad, of the photosensitive solder resist ink covering layer is flat; processing the photosensitive solder resist ink covering layer by adopting an exposure and development process to remove the photosensitive solder resist ink covering layer covering the bonding pad so as to expose the bonding pad; and curing the residual photosensitive solder resist ink covering layer to form a solder resist ink layer. The photosensitive solder resist ink covering layer is formed through the spin coating process, so that the first outer surface of the photosensitive solder resist ink covering layer is very flat, the thickness consistency of the solder resist ink layer is very high, and the ink color consistency of the display module can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of display, and more particularly to a method for processing a circuit board for a display module and a method for processing a display module. Background Technology

[0002] Currently, the PCBs used in COB and MIP are mainly HDI boards, or High-Density Interconnect Circuit Boards. Their structure includes a core board, copper foil, PP material, copper foil, and an ink layer stacked sequentially. The core board is a cured sheet of glass fiber and epoxy resin, while the PP material is a semi-cured sheet of glass fiber and semi-cured epoxy resin. The epoxy resin is in a semi-cured state and its main function is as an adhesive layer between the core board and the copper foil. During the manufacturing process, the core board, copper foil, PP material, and copper foil are pressed together by heat. Due to the uneven filling of the semi-cured epoxy resin and glass fiber in the PP material, the thickness of the PP material layer varies, thus increasing the thickness difference of the screen-printed ink. Since the ink is on the outermost layer of the PCB, the reflected light from the ink layer will differ when it reaches the human eye, resulting in differences in PCB ink color.

[0003] Since the uneven ink distribution caused by the differences in PP material after lamination and the tolerances of screen printing cannot be completely eliminated, a black adhesive film with a transmittance of less than 5-10% is applied on the original ink layer. Due to the high consistency of the adhesive film manufacturing process, the problem of inconsistent reflectivity caused by the inconsistency of the ink layer is solved. Moreover, the blackness of the adhesive film greatly absorbs light reflection, which further weakens the human eye's ability to distinguish differences in PCB boards.

[0004] An LED display screen is composed of multiple LED display modules spliced ​​together. When not lit, each LED display module appears black, and it is crucial to ensure that adjacent LED display modules have the same black color, i.e., color consistency. Currently, to achieve this black color, a black solder resist ink layer is typically formed on the surface of a PCB substrate using screen printing. However, screen printing involves multiple squeegees applying ink, causing it to seep through the mesh and cover the PCB substrate surface. In different areas of the PCB substrate, the thickness error of a single squeegee application can be 1-3µm or even higher. After multiple squeegees, the thickness difference of the solder resist ink layer at different locations can reach 5µm, with the overall thickness of the solder resist ink layer ranging from 25-30µm, demonstrating significant thickness variations. When multiple LED display modules are spliced ​​together, the color difference becomes obvious. Summary of the Invention

[0005] The purpose of this invention is to provide a method for processing a circuit board for a display module and a method for processing a display module, so as to solve the problem that the thickness error of the solder resist ink layer formed by screen printing in the prior art is large, resulting in obvious ink color differences.

[0006] To achieve the above objectives, the present invention provides a method for processing a circuit board for a display module, characterized by comprising the following steps: providing a first substrate for a display module, the first substrate having opposing first and second surfaces, the first surface having a plurality of pads for soldering LED chips; forming a photosensitive solder resist ink coating layer on the first surface by a spin coating process, the photosensitive solder resist ink coating layer covering the first substrate and the pads on the first substrate, the surface of the photosensitive solder resist ink coating layer being flat away from the pads; processing the photosensitive solder resist ink coating layer by an exposure and development process to remove the photosensitive solder resist ink coating layer covering the pads to expose the pads; and curing the remaining photosensitive solder resist ink coating layer to form a solder resist ink layer.

[0007] Preferably, the step of forming a photosensitive solder resist ink coating layer on the first surface by spin coating, wherein the photosensitive solder resist ink coating layer covers the first substrate and the pads on the first substrate, includes: providing a processing device, the processing device including a support fixture and a rotating shaft disposed at the bottom of the support fixture to drive the support fixture to rotate, the support fixture being plate-shaped and having an upward-facing upper surface, the support fixture having a mounting groove recessed inward from the upper surface; the size of the mounting groove corresponding to the first substrate, and when the first substrate is mounted in the mounting groove, the pads of the first substrate are located below the upper surface; mounting the first substrate in the mounting groove, with the pads of the first substrate facing upward; applying photosensitive solder resist ink material to the first surface and rotating the rotating shaft to form the photosensitive solder resist ink coating layer on the first surface by spin coating, the photosensitive solder resist ink coating layer covering the first substrate, the pads on the first substrate and extending to the upper surface.

[0008] Preferably, the support fixture is circular, and the mounting groove is located in the middle of the support fixture.

[0009] Preferably, a plurality of first adsorption elements are provided on the second surface of the first substrate, and a plurality of second adsorption elements are provided at the bottom of the mounting groove corresponding to the plurality of first adsorption elements. The first substrate is magnetically connected to the mounting groove through the first adsorption elements and the second adsorption elements.

[0010] Preferably, the processing apparatus further includes a lifting mechanism for lifting the first substrate. After the steps of applying photosensitive solder resist ink material to the first surface and rotating the rotating shaft to form the photosensitive solder resist ink coating layer on the first surface by spin coating process, wherein the photosensitive solder resist ink coating layer covers the first substrate, the pads on the first substrate and extends to the upper surface, the apparatus further includes: using the lifting mechanism to lift the first substrate upward to remove the first substrate from the mounting groove and separate the photosensitive solder resist ink coating layer on the first substrate and the pads from the photosensitive solder resist ink coating layer on the upper surface.

[0011] Preferably, before the step of using the lifting mechanism to lift the first substrate upward to remove the first substrate from the mounting groove and separate the photosensitive solder resist ink coating layer on the first substrate and the pad from the photosensitive solder resist ink coating layer on the upper surface, the method further includes: allowing the photosensitive solder resist ink coating layer to stand for a first time, the first time being greater than or equal to 0.5 minutes and less than or equal to 5 minutes.

[0012] Preferably, the photosensitive solder resist ink material comprises negative photosensitive resin, epoxy resin, photoinitiator, diluent, and carbon black pigment. The photosensitive ink cover layer has a first photosensitive area corresponding to a plurality of the solder pads and a second photosensitive area other than the first photosensitive area. The step of treating the photosensitive solder resist ink cover layer to remove the photosensitive solder resist ink cover layer covering the solder pads and exposing the solder pads by using an exposure and development process includes: treating the second photosensitive area by an exposure process to pre-cur the second photosensitive area; and treating the photosensitive solder resist ink layer by a development process to remove the first photosensitive area and expose the solder pads.

[0013] Preferably, the difference between the maximum and minimum height of the photosensitive solder resist ink coating layer away from the surface of the solder pad is less than 2 micrometers.

[0014] The present invention also provides a method for processing a display module, comprising the following steps: providing a circuit board obtained by the above-described method for manufacturing a circuit board; and soldering LED chips onto the pads of the circuit board.

[0015] Preferably, after the step of soldering LED chips onto the pads of the circuit board, the method further includes: spraying a thin-film protective material onto the solder resist ink layer and curing the thin-film protective material to form a thin-film protective layer attached to the surface of the solder resist ink layer, the light-emitting surface of the LED chip, and the side surface of the LED chip; providing a protective film, the bottom layer of which is a soft adhesive layer, attaching the protective film to the thin-film protective layer through the soft adhesive layer, and filling the spaces between adjacent LED chips with the soft adhesive layer. Compared with the prior art, the present invention forms a photosensitive solder resist ink coating layer through a spin coating process, which makes the first outer surface of the photosensitive solder resist ink coating layer very smooth, thereby making the thickness of the solder resist ink layer very consistent, thus significantly improving the ink color consistency of the display module. Attached Figure Description

[0016] Figure 1 This is a top view of the first substrate in an embodiment of the present invention.

[0017] Figure 2 This is a side view of the first substrate in an embodiment of the present invention.

[0018] Figure 3 This is a structural diagram of the processing device in an embodiment of the present invention.

[0019] Figure 4 This is a structural diagram of the first substrate after it is disposed in the mounting groove in an embodiment of the present invention.

[0020] Figure 5 This is a structural diagram of a photosensitive solder resist ink coating layer formed by spin coating a photosensitive solder resist ink material onto a first substrate using a processing device in an embodiment of the present invention.

[0021] Figure 6 This is a structural diagram of the lifting mechanism after lifting the first substrate in an embodiment of the present invention.

[0022] Figure 7 This is a structural diagram of the first cover layer after exposure and development in an embodiment of the present invention.

[0023] Figure 8 This is a structural diagram of the circuit board in an embodiment of the present invention.

[0024] Figure 9 This is a structural diagram of the display module in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached diagram: 1. First substrate; 11. First surface; 111. Pad area; 112. Non-pad area; 110. Pad group; 1101. Pad; 1102. Positive electrode pad; 1103. Negative electrode pad; 12. Second surface; 121. First adsorption element; 20. Processing device; 2. Support fixture; 21. Upper surface; 22. Mounting groove; 3. Rotation shaft; 4. Photosensitive solder resist ink cover layer; 401. First outer surface; 41. First cover layer; 411. First photosensitive area; 412. Second photosensitive area; 413. Solder resist ink layer; 42. Second cover layer; 5. Second adsorption element; 6. Lifting shaft; 7. LED chip; 701. Light-emitting surface; 71. Positive electrode; 72. Negative electrode; 8. Thin film protective layer; 9. Protective film; 10. Circuit board; 100. Display module. Detailed Implementation

[0026] To illustrate the technical content, structural features, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0027] like Figures 1 to 8 As shown, this embodiment of the invention provides a method for processing a circuit board for a display module, comprising the following steps: S1. A first substrate 1 for a display module 100 is provided. The first substrate 1 has a first surface 11 and a second surface 12 facing each other. The first surface 11 is provided with a plurality of pads 1101 for soldering LED chips 7; specifically, as shown in the figure... Figure 1 , Figure 2 as well as Figure 9 As shown, the first substrate 1 can be a PCB substrate, glass substrate, BT substrate, or other circuit substrate. Pads 1101 are used to solder LED chips 7. Pads 1101 include spaced-apart positive electrode pads 1102 and negative electrode pads 1103. Positive electrode pads 1102 are used to solder the positive electrode 71 of the LED chip 7, and negative electrode pads 1103 are used to solder the negative electrode 72 of the LED chip 7. The circuit substrate 10 typically includes several pad groups 110, each pad group 110 including at least three pads 1101. The pad area 111 is the location of the pads 1101 and the positive electrode of each pad 1101. The area between pad 1102 and the corresponding negative electrode pad 1103. Of course, in some other specific embodiments, pad area 111 may refer only to the location of several pads 1101, or pad area 111 may refer only to a part of the location of several pads 1101. That is, as long as the exposed part of the positive electrode pad 1102 and the exposed part of the negative electrode pad 1103 can be soldered to the positive electrode 71 and the negative electrode 72, the exposed area of ​​pad 1101 can be reduced, so as to further improve the consistency of ink color. The area on the first substrate 1 other than pad area 111 is non-pad area 112.

[0028] S2. A photosensitive solder resist ink coating layer 4 is formed on the first surface 11 by a spin coating process. The photosensitive solder resist ink coating layer 4 covers the first substrate 1 and the pads 1101 on the first substrate 1. The surface of the photosensitive solder resist ink coating layer 4 away from the pads 1101 is flat. The spin coating process specifically includes a low-speed spin coating droplet stage and a high-speed spin coating homogenization stage. In the low-speed spin coating droplet stage, the spin coating speed is set to 500~1500 rpm and the spin coating time is 2~10s to complete the application of the required photosensitive solder resist ink material. In the high-speed spin coating homogenization stage, the spin coating speed is set to 2500~3500 rpm and the spin coating time is 20~40s to form a uniform photosensitive solder resist ink coating layer 4. Figure 5As shown, the surface of the photosensitive solder resist ink coating layer 4 away from the solder pad 1101 is the first outer surface 401. The first outer surface 401 formed by spin coating is very flat. The difference between the maximum and minimum height of the first outer surface 401 is less than 2 micrometers. Therefore, the photosensitive solder resist ink coating layer 4 formed by spin coating is flatter than the solder resist ink layer obtained by screen printing. This ensures that the ink color of adjacent LED display modules 100 is the same, thus guaranteeing ink color consistency. The height of the first outer surface 401 is higher than the height of the outer surface of the solder pad 1101.

[0029] S3. The photosensitive solder resist ink coating layer 4 is removed from the solder pad 1101 using an exposure and development process to expose the solder pad 1101; specifically, as follows: Figure 1 as well as Figure 7 As shown, removing the photosensitive solder resist ink coating layer 4 covering the pad area 111 exposes the pad 1101 for subsequent soldering of the LED chip 7.

[0030] S4. The remaining photosensitive solder resist ink coating layer 4 is cured to form solder resist ink layer 413. Specifically, as follows... Figures 7 to 8 As shown, the remaining photosensitive solder resist ink coating layer 4 is baked and cured. The baking temperature can be 150 degrees Celsius, and the baking time can be greater than or equal to 1 hour and less than or equal to 4 hours. Because the first outer surface 401 of the photosensitive solder resist ink coating layer 4 is very flat, the thickness of the cured solder resist ink layer 413 is basically consistent, thus ensuring that the ink color of adjacent display modules 100 is the same, guaranteeing ink color consistency.

[0031] In this embodiment of the invention, a photosensitive solder resist ink coating layer 4 is formed by spin coating process, which makes the first outer surface 401 of the photosensitive solder resist ink coating layer 4 very flat, thereby making the thickness of the solder resist ink layer 413 very consistent, thus significantly improving the ink color consistency of the display module 100.

[0032] In this embodiment of the invention, step S2, forming a photosensitive solder resist ink cover layer 4 on the first surface 11 by spin coating, wherein the photosensitive solder resist ink cover layer 4 covers the first substrate 1 and the solder pads 1101 on the first substrate 1, includes the following steps: S21. A processing apparatus 20 is provided. The processing apparatus 20 includes a support fixture 2 and a rotating shaft 3 disposed at the bottom of the support fixture 2 to drive the support fixture 2 to rotate. The support fixture 2 is plate-shaped and has an upper surface 21 facing upward. The support fixture 2 has a mounting groove 22 recessed inward from the upper surface 21. The size of the mounting groove 22 corresponds to that of the first substrate 1, and when the first substrate 1 is mounted in the mounting groove 22, the pads 1101 of the first substrate 1 are located below the upper surface 21. Specifically, as shown... Figures 3 to 4As shown, the first substrate 1 is generally rectangular or square. The size of the mounting groove 22 is a predetermined size larger than the size of the first substrate 1 to allow for a clearance fit between the first substrate 1 and the mounting groove 22. For example, when the first substrate 1 is rectangular, the difference between the length of the mounting groove 22 and the length of the first substrate 1 is 0.1 mm, and the difference between the width of the mounting groove 22 and the width of the first substrate 1 is 0.1 mm. Furthermore, the solder pads 1101 of the first substrate 1 are located below the upper surface 21, allowing the photosensitive solder resist ink material to extend onto the upper surface 21 during spin coating, resulting in a higher flatness of the photosensitive solder resist ink coating layer 4 on the first substrate 1. In addition, the support fixture 2 can be circular, and the mounting groove 22 is located in the middle of the support fixture 2, thereby ensuring high flatness during spin coating.

[0033] S22. The first substrate 1 is mounted in the mounting groove 22, with the pads 1101 of the first substrate 1 facing upwards, thereby facilitating the application of photosensitive solder resist ink material on the first substrate 1 and the pads 1101, specifically as follows: Figure 4 As shown.

[0034] S23. A photosensitive solder resist ink material is applied to the first surface 11, and the rotating shaft 3 is rotated to form a photosensitive solder resist ink cover layer 4 on the first surface 11 by a spin coating process. The photosensitive solder resist ink cover layer 4 covers the first substrate 1, the solder pads 1101 on the first substrate 1, and extends to the upper surface 21. Specifically, as shown... Figure 5 As shown.

[0035] In this embodiment of the invention, a plurality of first adsorption members 121 are provided on the second surface 12 of the first substrate 1, and a plurality of second adsorption members 5 are provided at the bottom of the mounting groove 22 corresponding to the plurality of first adsorption members 121. The first substrate 1 is magnetically connected to the mounting groove 22 through the first adsorption members 121 and the second adsorption members 5. Specifically, the first adsorption member 121 can be a first magnet, and the second adsorption member 5 can be a second magnet. The adsorption force of the first magnet and the second magnet connects the first substrate 1 to the mounting groove 22, and the first substrate 1 can be easily connected to the mounting groove 22. Of course, one of the first adsorption members 121 and the second adsorption member 5 can be set as ferromagnetic, and the other as a magnetic metal part. The first adsorption members 121 are evenly distributed at the edge and middle of the second surface 12, and the second adsorption members 5 are set one-to-one with the first adsorption members 121 to adsorb each other. The setting of the positions of the first adsorption members 121 and the second adsorption members 5 ensures that the first substrate 1 is effectively flattened, overcoming the problem of unevenness of the first substrate 1 itself.

[0036] In this embodiment of the invention, the processing apparatus 20 further includes a lifting mechanism for lifting the first substrate 1. Step S23, after applying photosensitive solder resist ink material to the first surface 11 and rotating the rotating shaft 3 to form a photosensitive solder resist ink coating layer 4 on the first surface 11 via a spin coating process, after the photosensitive solder resist ink coating layer 4 covers the first substrate 1, the solder pads 1101 on the first substrate 1, and extends to the upper surface 21, further includes: S24. The first substrate 1 is lifted upward using a lifting mechanism to remove it from the mounting groove 22 and separate the photosensitive solder resist ink coating 4 on the first substrate 1 and the pad 1101 from the photosensitive solder resist ink coating 4 on the upper surface 21. Specifically, the photosensitive solder resist ink coating 4 on the first substrate 1 and the pad 1101 is the first coating layer 41, and the photosensitive solder resist ink coating 4 on the upper surface 21 is the second coating layer 42. The lifting mechanism includes a lifting shaft 6, which extends into the mounting groove 22 from below to lift the first substrate 1 upward when it is necessary to remove it from the mounting groove 22. There can be two lifting shafts 6, which can lift both ends of the first substrate 1 for stable lifting. The lifting shaft 6 can be the output shaft of a cylinder. The lifting mechanism is fixed to the support fixture 2 to rotate with the support fixture 2. After the spin coating operation is completed, the first substrate 1 is lifted by the lifting mechanism to overcome the magnetic attraction between the first adsorption member 121 and the second adsorption member 5, and to separate the first adsorption member 121 and the second adsorption member 5.

[0037] It should be noted that during the lifting process, when the second cover layer 42 separates from the first cover layer 41, although the second cover layer 42 slightly pulls on the first cover layer 41, causing defects on the edge of the solder resist ink layer 413 of the subsequent circuit board 10, the processed edge of the circuit board 10 will be removed in the subsequent process of manufacturing the display module 100, and the defective part of the solder resist ink layer 413 will also be removed, thus ensuring the ink color consistency of the display module 100.

[0038] In this embodiment of the invention, before step S24, which involves using a lifting mechanism to lift the first substrate 1 upwards to remove it from the mounting groove 22 and separate the photosensitive solder resist ink coating layer 4 on the first substrate 1 and the solder pad 1101 from the photosensitive solder resist ink coating layer 4 on the upper surface 21, the method further includes: S024, the photosensitive solder resist ink coating layer 4 is left to stand for a first time, which is greater than or equal to 0.5 minutes and less than or equal to 5 minutes. Specifically, by leaving the photosensitive solder resist ink coating layer 4 to stand for a first time, the photosensitive solder resist ink material is naturally formed into a film, and its fluidity is reduced. In the subsequent step S24, when the first substrate 1 is lifted upward using the lifting mechanism, the surface of the photosensitive solder resist ink coating layer 4 can be better ensured to be flat.

[0039] In this embodiment of the invention, the photosensitive solder resist ink material comprises negative photosensitive resin, epoxy resin, photoinitiator, diluent, and carbon black pigment. The photosensitive solder resist ink cover layer 4 has a first photosensitive area 411 corresponding to a plurality of solder pads 1101 and a second photosensitive area 412 other than the first photosensitive area 411. Step S3, using an exposure and development process to process the photosensitive solder resist ink cover layer 4 to remove the photosensitive solder resist ink cover layer 4 covering the solder pads 1101 to expose the solder pads 1101, includes the following steps: S31. The second photosensitive area 412 is treated by an exposure process to preliminarily cure the second photosensitive area 412. Specifically, a mask is used to cover the first photosensitive area 411 of the photosensitive solder resist ink coating layer 4, and the second photosensitive area 412 is irradiated with a UV lamp with a wavelength of 365 nm or 395 nm. Alternatively, a mercury lamp can be used to irradiate the second photosensitive area 412, thereby causing the second photosensitive area 412 to undergo a cross-linking reaction. The second photosensitive area 412 after the cross-linking reaction is insoluble in the developing solution used in the developing process of step S32.

[0040] S32. The photosensitive solder resist ink layer 413 is processed by a developing process to remove the first photosensitive area 411 to expose the solder pad 1101. Specifically, as follows... Figures 6 to 7 As shown, the first substrate 1 and the photosensitive solder resist ink coating layer 4 are placed in the developing solution. The photosensitive solder resist ink material in the second photosensitive area 412 after exposure process is insoluble in the developing solution, while the photosensitive solder resist ink material in the first photosensitive area 411 is soluble in the developing solution, thereby removing the first photosensitive area 411 and retaining only the second photosensitive area 412.

[0041] It should be noted that when the composition of photosensitive solder resist ink includes negative photosensitive resin, epoxy resin, photoinitiator, diluent, and carbon black pigment, the photosensitive solder resist ink is a photolithographic negative resist with added carbon black pigment. The negative photosensitive resin can be one or more of cyclized polyisoprene, bisphenol A type epoxy resin, polymethyl methacrylate (PMMA), or modified acrylate. The photoinitiator can be a diazid compound, benzophenone, or benzoin ether. The diluent can be xylene, propylene glycol methyl ether acetate, or ethylene glycol monoethyl ether. The first developer generally uses organic solvents such as xylene or propylene glycol methyl ether acetate (PGMEA). Of course, the photolithographic negative resist and the corresponding developer are conventional photolithography process materials, and the specific materials can be selected according to actual needs, which will not be elaborated here.

[0042] In some other specific embodiments, when the photosensitive solder resist ink material may include positive photosensitive resin, epoxy resin, photoacid generator, diluent, and carbon black pigment, the photosensitive solder resist ink is a photoresist with added carbon black pigment. The positive photosensitive resin may be a linear phenolic resin, acrylate, or fluorinated resin; the photoacid generator may be a triphenylsulfonate or sulfonate; and the diluent may be propylene glycol methyl ether acetate, ethyl lactate, or cyclohexanone. In this case, the first photosensitive area 411 is exposed, and the first photosensitive area 411 is removed using a developer solution such as tetramethylammonium hydroxide (TMAH). Of course, the photoresist and the corresponding developer solution are conventional photolithography process materials, and the specific materials can be selected according to actual needs, which will not be elaborated here.

[0043] In this embodiment of the invention, the difference between the maximum and minimum height of the photosensitive solder resist ink coating layer 4 away from the surface of the solder pad 1101 is less than 2 micrometers, which effectively ensures the flatness of the first outer surface 401 of the photosensitive solder resist ink coating layer 4.

[0044] This invention also provides a method for processing a display module 100, comprising the following steps: S10, the circuit board 10 obtained by the above-described method for manufacturing a circuit board; specifically, as shown in... Figures 1 to 9 As shown, the pad 1101 includes positive electrode pads 1102 and negative electrode pads 1103 spaced apart. The positive electrode pads 1102 are used to solder the positive electrode 71 of the LED chip 7, and the negative electrode pads 1103 are used to solder the negative electrode 72 of the LED chip 7. The circuit board 10 typically includes several pad groups 110, each pad group 110 including at least three pads 1101. The pad area 111 is the location of the pads 1101 and the positive electrode pad 1102 of each pad 1101. The area between the corresponding negative electrode pads 1103. Of course, in some other specific embodiments, the pad area 111 may refer only to the location of several pads 1101, or the pad area 111 may refer only to a portion of the location of several pads 1101. That is, as long as the exposed positive electrode pads 1102 and the exposed negative electrode pads 1103 can be soldered to the positive electrode 71 and the negative electrode 72, the exposed area of ​​the pads 1101 can be reduced, thereby further improving the consistency of the ink color.

[0045] S20. Solder the LED chip 7 onto the pad 1101 of the circuit board 10. Specifically, as follows... Figure 9 As shown, LED chips 7 are soldered onto the positive electrode pad 1102 and the corresponding negative electrode pad 1103 of the circuit board 10.

[0046] In this embodiment of the invention, after soldering the LED chip 7 onto the pads 1101 of the circuit board 10 in step S20, the method further includes: S30. A thin film protective material is sprayed onto the solder resist ink layer 413 and cured to form a thin film protective layer 8 attached to the surface of the solder resist ink layer 413, the light-emitting surface 701 of the LED chip 7, and the side surface of the LED chip 7. Specifically, the thin film protective material includes a uniformly mixed adhesive material and a thinner, with a ratio of 1:3 to 3:5. The thinner ensures that the adhesive material has sufficient fluidity in the nozzle. During the process of spraying the thin film protective material from the nozzle (from the nozzle to the LED chip 7 and the solder resist ink layer 413), the thinner evaporates in the air. Finally, when the adhesive material is sprayed onto the LED surface, the fluidity of the adhesive material is greatly reduced, so that it adheres to the surface of the LED chip 7 and forms a protective layer shape.

[0047] S40. A protective film 9 is provided. The bottom layer of the protective film 9 is a soft adhesive layer. The protective film 9 is attached to the thin film protective layer 8 through the soft adhesive layer, and the soft adhesive layer fills the spaces between adjacent LED chips 7. Specifically, the bottom layer of the protective film 9 is a soft adhesive layer, which is an OCA soft adhesive layer. Of course, other elastic adhesive materials can also be selected as the soft adhesive layer, not limited to OCA soft adhesive. The protective film 9 also includes a PET transparent layer formed on the soft adhesive layer and a black ink layer formed on the PET transparent layer. The protective film 9 also includes a functional layer formed on the black ink layer. The functional layer is an AG layer, an AR layer, or an AF layer, etc. Among them, the AR (Anti-Reflection) layer is an anti-reflective film layer or glass, the AG (Anti-Glare) layer is an anti-glare film layer or glass, and the AF (Anti-Fingerprint) layer is an anti-fingerprint film layer or glass. In another embodiment, the protective film 9 includes a carbon black layer formed on the soft adhesive layer and a PET transparent layer formed on the carbon black layer. Of course, other ink materials can be used to make ink to replace the carbon black layer, and it is not limited to carbon black. Similarly, other transparent insulating materials can be used to make the transparent layer to replace the PET transparent layer, and it is not limited to PET. The protective film 9 also includes functional layers formed on the PET transparent layer. These functional layers can be AG layers, AR layers, or AF layers, etc.

[0048] The above-disclosed examples are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for processing a circuit board for a display module, characterized in that, Includes the following steps: A first substrate for a display module is provided, the first substrate having opposing first and second surfaces, the first surface having a plurality of pads for soldering LED chips; A photosensitive solder resist ink coating layer is formed on the first surface by a spin coating process. The photosensitive solder resist ink coating layer covers the first substrate and the pads on the first substrate. The surface of the photosensitive solder resist ink coating layer away from the pads is flat. The photosensitive solder resist ink covering layer is removed by an exposure and development process to expose the solder pad; The remaining photosensitive solder resist ink coating layer is cured to form a solder resist ink layer.

2. The method for processing the circuit board of the display module as described in claim 1, characterized in that, Forming a photosensitive solder resist ink coating layer on the first surface by spin coating, wherein the photosensitive solder resist ink coating layer covers the first substrate and the pads on the first substrate, includes the following steps: A processing apparatus is provided, the processing apparatus including a support fixture and a rotating shaft disposed at the bottom of the support fixture to drive the support fixture to rotate, the support fixture being plate-shaped and having an upward-facing upper surface, the support fixture having a mounting groove recessed inward from the upper surface; the size of the mounting groove is set to correspond to the first substrate, and when the first substrate is mounted in the mounting groove, the pads of the first substrate are located below the upper surface; The first substrate is mounted in the mounting groove, with the pads of the first substrate facing upwards; A photosensitive solder resist ink material is disposed on the first surface and the rotating shaft is rotated to form a photosensitive solder resist ink cover layer on the first surface by a spin coating process. The photosensitive solder resist ink cover layer covers the first substrate, the solder pads on the first substrate and extends to the upper surface.

3. The method for processing the circuit board of the display module as described in claim 2, characterized in that, The support fixture is circular, and the mounting groove is located in the middle of the support fixture.

4. The method for processing the circuit board of the display module as described in claim 2, characterized in that, The second surface of the first substrate is provided with a plurality of first adsorption elements, and the bottom of the mounting groove is provided with a plurality of second adsorption elements corresponding to the plurality of first adsorption elements. The first substrate is magnetically connected to the mounting groove through the first adsorption elements and the second adsorption elements.

5. The method for processing the circuit board of the display module as described in claim 2, characterized in that, The processing apparatus further includes a lifting mechanism for lifting the first substrate. After the steps of applying photosensitive solder resist ink material to the first surface and rotating the rotating shaft to form a photosensitive solder resist ink coating layer on the first surface via a spin coating process, wherein the photosensitive solder resist ink coating layer covers the first substrate, the solder pads on the first substrate, and extends to the upper surface, the apparatus further includes: The lifting mechanism is used to lift the first substrate upwards to remove the first substrate from the mounting groove and separate the photosensitive solder resist ink coating on the first substrate and the pad from the photosensitive solder resist ink coating on the upper surface.

6. The method for processing the circuit board of the display module as described in claim 5, characterized in that, Before the step of lifting the first substrate upward using the lifting mechanism to remove the first substrate from the mounting groove and separating the photosensitive solder resist coating on the first substrate and the pads from the photosensitive solder resist coating on the upper surface, the method further includes: The photosensitive solder resist ink coating layer is left to stand for a first time, which is greater than or equal to 0.5 minutes and less than or equal to 5 minutes.

7. The method for processing the circuit board of the display module as described in claim 2, characterized in that, The photosensitive solder resist ink material comprises negative photosensitive resin, epoxy resin, photoinitiator, diluent, and carbon black pigment. The photosensitive ink coating layer has a first photosensitive area corresponding to a plurality of solder pads and a second photosensitive area other than the first photosensitive area. The step of removing the photosensitive solder resist ink coating layer covering the solder pads by processing the photosensitive solder resist ink coating layer with an exposure and development process to expose the solder pads includes: The second photosensitive area is processed using an exposure process to pre-cure the second photosensitive area; The photosensitive solder resist ink layer is processed by a developing process to remove the first photosensitive area and expose the solder pad.

8. The method for processing the circuit board of the display module as described in claim 1, characterized in that, The difference between the maximum and minimum height of the photosensitive solder resist ink coating layer away from the surface of the solder pad is less than 2 micrometers.

9. A method for processing a display module, characterized in that, Includes the following steps: A circuit board manufactured by the method of any one of claims 1 to 8 is provided; LED chips are soldered onto the pads of the circuit board.

10. The processing method of the display module as described in claim 9, characterized in that, After the step of soldering the LED chip onto the pads of the circuit board, the method further includes: A thin film protective material is sprayed onto the solder resist ink layer and cured to form a thin film protective layer attached to the surface of the solder resist ink layer, the light-emitting surface of the LED chip, and the side surface of the LED chip. A protective film is provided, the bottom layer of which is a soft adhesive layer. The protective film is attached to the thin film protective layer through the soft adhesive layer, and the soft adhesive layer fills the spaces between adjacent LED chips.

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