LED lamp panel and coating method therefor

Abstract

An LED lamp panel and a coating method therefor. The coating method for the LED lamp panel comprises the following steps: providing an LED lamp panel, the LED lamp panel comprising a PCB substrate (12) and lamp beads (11) provided on the surface of the PCB substrate (12), and each lamp bead (11) having a light-emitting surface and a side surface surrounding the light-emitting surface; applying a photosensitive ink (21) onto the light-emitting surfaces and side surfaces of the lamp beads (11) and the surface of the PCB substrate (12) which is provided with no lamp bead (11); and performing patterning mask exposure on the photosensitive ink (21), removing the photosensitive ink (21) covering the light-emitting surfaces, and retaining the photosensitive ink (21) covering the side surfaces. The LED coating method has high uniformity, and can mitigate the problems of light leakage from the side surfaces of lamp beads (11) of LED lamp panels, and ink color inconsistency between the LED lamp panels.

Description

LED light board and coating method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 2024101060728, filed on January 24, 2024, entitled “LED light board and coating method thereof,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of LED display technology, and in particular to an LED light board and a coating method thereof. Background Art

[0004] Light-emitting diode (LED) displays are widely used in the display industry due to their high brightness, high luminous efficiency, vivid colors, high contrast, wide operating temperature range, fast response time, and low energy consumption. LED displays are typically composed of multiple LED panels, which consist of a printed circuit board (PCB) with multiple LED beads soldered to it. To protect the circuitry on the PCB, a layer of ink is applied to the surface of the PCB.

[0005] At present, the design of lamp beads in LED light boards is becoming more and more dense, and the distance between lamps is becoming smaller and smaller. Therefore, the color difference of ink after the LED light boards are assembled has a more obvious impact on the brightness consistency and color fidelity of the LED display.

[0006] Traditional LED light panels typically use a surface coating process to darken the lamp surface and improve ink color consistency. However, this improvement is limited and reduces the light extraction efficiency of the LED chip. Existing technology also uses a slot inkjet process to produce LED light panels, but this method is inefficient and unsuitable for smaller LED slots. Summary of the Invention

[0007] Based on this, it is necessary to provide an LED light board and a coating method thereof. The LED light board coating method of the present application can improve the problems of light leakage from the side of the LED light beads and inconsistent ink color.

[0008] This application provides a method for coating an LED light panel, comprising the following steps:

[0009] An LED light board is provided, comprising a PCB substrate and a lamp bead arranged on a surface of the PCB substrate, wherein the lamp bead has a light emitting surface and a side surface surrounding the light emitting surface;

[0010] Applying photosensitive ink on the light-emitting surface and side surfaces of the lamp beads and the surface of the PCB substrate where no lamp beads are provided;

[0011] The photosensitive ink is exposed through a patterned mask to remove the photosensitive ink covering the light-emitting surface and retain the photosensitive ink covering the side surface.

[0012] In some embodiments, before exposing the photosensitive ink to a patterned mask, the following steps are further included:

[0013] The photosensitive ink is pre-cured.

[0014] In some embodiments, the pre-curing temperature is 60°C to 90°C.

[0015] In some embodiments, the pre-curing time is 15 min to 40 min.

[0016] In some embodiments, after removing the photosensitive ink covering the light-emitting surface and retaining the photosensitive ink covering the side surface, the method further includes:

[0017] The remaining photosensitive ink is subjected to secondary curing.

[0018] In some embodiments, the temperature of the secondary curing is 80°C to 150°C.

[0019] In some embodiments, the secondary curing time is 30 min to 120 min.

[0020] In some embodiments, exposing the photosensitive ink through a patterned mask to remove the photosensitive ink covering the light-emitting surface and retaining the photosensitive ink covering the side surface comprises the following steps:

[0021] Curing the photosensitive ink covering the side surface and the surface of the PCB substrate where the lamp beads are not provided by exposing the photosensitive ink through a patterned mask;

[0022] The photosensitive ink covering the light-emitting surface is cleaned using an alkaline solution.

[0023] In some embodiments, the following steps are further included before the patterned mask exposure of the photosensitive ink:

[0024] A protective film layer is prepared on the photosensitive ink, wherein the material of the protective film layer includes at least one of a matte agent, a waterproof coating, and a nano coating.

[0025] In some embodiments, the photosensitive ink includes a first ink composition and a second ink composition;

[0026] The first ink composition comprises the following components in percentage by mass: 20% to 70% of a prepolymer, 5% to 20% of a first epoxy resin, 1% to 10% of a photoinitiator, 0.1% to 1% of a carbon black pigment, 5% to 50% of a first inorganic filler, 1% to 10% of an additive, and 10% to 40% of a first solvent, wherein the additive comprises at least one of a leveling agent, a defoaming agent, and a dispersant;

[0027] The second ink composition includes the following components in the following mass percentages: 5% to 20% of a thermal curing accelerator, 5% to 10% of a photopolymerizable monomer, 10% to 40% of a second epoxy resin, 10% to 20% of a stabilizer, 5% to 40% of a second inorganic filler, and 10% to 40% of a second solvent.

[0028] In some embodiments, the mass ratio of the first ink composition to the second ink composition in the photosensitive ink is (2-5):1.

[0029] In some embodiments, the photosensitive ink further comprises oil-opening water, and the ratio of the mass of the oil-opening water to the total mass of the first ink composition and the second ink composition is 1:(8-20).

[0030] The present application also provides an LED light board, which is obtained by coating using any of the above-mentioned LED light board coating methods.

[0031] In the above-mentioned LED light board coating method, the surface of the PCB substrate on which the lamp beads are provided is directly coated with photosensitive ink, which can achieve better uniformity of ink coating. The photosensitive ink is then subjected to graphic mask exposure, the photosensitive ink covering the light-emitting surface is removed, and the photosensitive ink covering the side is retained, thereby completing the coating of the LED light board to achieve better coverage of the sides of the lamp beads by the photosensitive ink. Compared with the method of directly spraying ink at the lamp seam in the traditional coating process of LED light boards, the LED coating method has higher uniformity and can improve the problems of light leakage from the sides of the lamp beads of the LED light board and inconsistent ink color. Furthermore, this method can also achieve the effect of small-pitch filling that is difficult to achieve with the traditional coating process of LED light boards. At the same time, when using the screen printing process for photosensitive ink coating, the thickness of the ink layer at the lamp seam can also be made higher than the height of the lamp beads, which can achieve a better effect of reducing light leakage from the sides of the lamp beads. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic diagram of a process for coating an LED light panel according to an embodiment of the present application;

[0033] FIG2 is a schematic diagram of spray coating and mask exposure of an LED light board in Example 1 of the present application;

[0034] FIG3 is a schematic diagram of secondary spray coating and secondary laser cleaning of an LED light panel in Example 1 of the present application;

[0035] FIG4 is a schematic diagram of screen printing and mask exposure of an LED light board in Example 2 of the present application;

[0036] Figure 5 is a schematic diagram of the structure after the LED light board is cleaned in Example 2 of the present application.

[0037] Reference numerals:

[0038] 11. Lamp beads; 111. R-MLED; 112. G-MLED; 113. B-MLED; 12. PCB substrate; 13. Driver IC; 21. Photosensitive ink; 22. Protective film layer; 30. Mask; 40. UV lamp; 50. Spraying equipment; 60. Laser; 70. Scraper. DETAILED DESCRIPTION

[0039] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0043] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0044] 1 , an embodiment of the present application provides a method for coating an LED light panel, comprising the following steps:

[0045] An LED light board is provided, comprising a PCB substrate 12 and a lamp bead 11 disposed on a surface of the PCB substrate 12, wherein the lamp bead 11 has a light emitting surface and a side surface surrounding the light emitting surface;

[0046] Apply the photosensitive ink 21 to the light-emitting surface and side surfaces of the lamp bead 11 and the surface of the PCB substrate 12 where the lamp bead 11 is not provided;

[0047] The photosensitive ink 21 is exposed through a patterned mask to remove the photosensitive ink 21 covering the light-emitting surface, while retaining the photosensitive ink 21 covering the side surfaces.

[0048] In the above-mentioned LED light board coating method, the photosensitive ink 21 is directly coated on the entire surface of the PCB substrate 12 on which the lamp beads 11 are provided, which can achieve better uniformity of ink coating. The photosensitive ink 21 is then exposed using a graphic mask to remove the photosensitive ink 21 covering the light-emitting surface, while retaining the photosensitive ink 21 covering the side, thereby completing the coating of the LED light board to achieve better coverage of the sides of the lamp beads 11 by the photosensitive ink 21. Compared with the method of directly spraying ink at the lamp seam in the traditional LED light board coating process, this LED coating method has higher uniformity and can improve the problems of light leakage from the side of the LED lamp beads and inconsistent ink color. Furthermore, this method can also achieve the effect of filling small gaps that are difficult to achieve with the traditional LED light board coating process. At the same time, when using the screen printing process for photosensitive ink coating, the thickness of the ink layer at the lamp seam can also be made higher than the height of the lamp beads 11, which can achieve a better effect of reducing light leakage from the side of the lamp beads 11.

[0049] It can be understood that in the LED lamp board, each lamp bead 11 has a light-emitting surface. Taking Figure 2 as an example, the light-emitting surface of the lamp bead 11 in the LED lamp board is the surface of the lamp bead 11 away from the PCB substrate 12, and the four side surfaces surrounding the light-emitting surface are the side surfaces of the lamp bead 11.

[0050] In some embodiments, before the photosensitive ink 21 is subjected to patterned mask exposure, the following step is further included: pre-curing the photosensitive ink 21 .

[0051] Pre-curing the photosensitive ink 21 can solidify the surface of the photosensitive ink 21 , reduce the flow and damage of the photosensitive ink 21 in subsequent steps, and facilitate the formation of the mask 30 on the surface of the photosensitive ink 21 .

[0052] In some embodiments, the pre-curing temperature is 60°C to 90°C. Within this pre-curing temperature range, the surface pre-curing effect of the photosensitive ink 21 is better, while also preventing over-curing of the photosensitive ink 21, facilitating the subsequent removal of the photosensitive ink 21 from the light-emitting surface. Optionally, the pre-curing temperature is 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C, 84°C, 86°C, 88°C, or 90°C. Alternatively, the pre-curing temperature may be within a range between any two of the above temperatures.

[0053] In some embodiments, the pre-curing time is 15 to 40 minutes. Within this pre-curing time range, the surface pre-curing effect of the photosensitive ink 21 is better, while also preventing over-curing of the photosensitive ink 21, facilitating subsequent removal of the photosensitive ink 21 from the light-emitting surface. Alternatively, the pre-curing time is 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, or 40 minutes. Alternatively, the pre-curing time may be within a range between any two of the above times.

[0054] In some embodiments, after removing the photosensitive ink 21 covering the light-emitting surface and retaining the photosensitive ink 21 covering the side surfaces, the method further includes: performing secondary curing on the remaining photosensitive ink 21 .

[0055] During the mask exposure process, the curing effect of the photosensitive ink 21 may not be complete. Removing the photosensitive ink 21 covering the light-emitting surface, retaining the photosensitive ink 21 covering the side, and performing secondary curing on the remaining photosensitive ink 21 can completely cure the photosensitive ink 21 and achieve a better coating effect.

[0056] In some embodiments, the temperature of the secondary curing is 80°C to 150°C.

[0057] Within this secondary curing temperature range, the photosensitive ink 21 is cured well, and a good coating effect can be achieved on the side of the lamp bead 11. Optionally, the secondary curing temperature is 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, or 150°C. Alternatively, the secondary curing temperature may be within a range between any two of the above temperatures.

[0058] In some embodiments, the secondary curing time is 30 min to 120 min.

[0059] Within this secondary curing time range, the photosensitive ink 21 is cured effectively, and a good coating effect can be achieved on the side of the lamp bead 11. Optionally, the secondary curing time is 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, or 120 minutes. Alternatively, the secondary curing time can be within a range between any two of the above times.

[0060] In some embodiments, performing patterned mask exposure on the photosensitive ink 21 to remove the photosensitive ink 21 covering the light-emitting surface and retaining the photosensitive ink 21 covering the side surfaces includes the following steps:

[0061] The photosensitive ink 21 covering the side surfaces and the surface of the PCB substrate 12 where the lamp beads 11 are not provided is cured by exposing the PCB substrate 12 through a patterned mask;

[0062] The photosensitive ink 21 covering the light-emitting surface is cleaned using an alkaline solution.

[0063] In some embodiments, the exposure energy is 200 mJ / cm 2 ~500mJ / cm 2 Optionally, the energy of the mask exposure is 200mJ / cm 2 , 250mJ / cm 2 、300mJ / cm 2 、350mJ / cm 2 , 400mJ / cm 2 , 450mJ / cm 2 or 500mJ / cm 2 Alternatively, the energy of the mask exposure may also be within the range between any two of the above energies.

[0064] In some embodiments, the exposure time is 30s to 60s. Alternatively, the exposure time is 30s, 35s, 40s, 45s, 50s, 55s, or 60s. Alternatively, the exposure time may be within a range between any two of the above times.

[0065] In some embodiments, the alkaline solution includes at least one of a sodium carbonate solution and a sodium bicarbonate solution.

[0066] In some embodiments, the mass percentage concentration of the alkaline solution is 0.5% to 2%. Alternatively, the mass percentage concentration of the alkaline solution is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%. Alternatively, the mass percentage concentration of the alkaline solution can also be within the range between any two of the above percentage concentrations.

[0067] In some embodiments, the cleaning time is 30s to 120s. Alternatively, the cleaning time is 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, or 120s. Alternatively, the cleaning time may be within a range between any two of the above times.

[0068] In some embodiments, the following steps are further included before the patterned mask exposure of the photosensitive ink 21:

[0069] A protective film layer 22 is prepared on the surface of the photosensitive ink 21 . The material of the protective film layer 22 includes at least one of a matte agent, a waterproof coating, and a nano coating.

[0070] In some embodiments, after the secondary curing of the remaining photosensitive ink 21, the following steps are further included:

[0071] Perform a second cleaning on the light-emitting surface.

[0072] The second cleaning can clean the residual solidified ink on the light emitting surface.

[0073] In some embodiments, the second cleaning includes at least one of plasma cleaning and laser cleaning.

[0074] In some embodiments, laser cleaning comprises ultraviolet pulsed laser cleaning.

[0075] In some embodiments, during ultraviolet pulse laser cleaning, the laser energy of a single pulse is 20 μJ to 100 μJ. Within the above-mentioned range of the laser energy of a single pulse, the cleaning effect on the residual ink is improved, and the luminous efficiency of the lamp bead 11 can be ensured to be unaffected. Optionally, the laser energy of a single pulse is 20 μJ, 30 μJ, 40 μJ, 50 μJ, 60 μJ, 70 μJ, 80 μJ, 90 μJ or 100 μJ. Alternatively, during ultraviolet pulse laser cleaning, the laser energy of a single pulse can also be within the range between any two of the above-mentioned energies.

[0076] In some embodiments, the photosensitive ink 21 includes a first ink composition and a second ink composition;

[0077] The first ink composition includes the following components in percentage by mass: 20% to 70% of a prepolymer, 5% to 20% of a first epoxy resin, 1% to 10% of a photoinitiator, 0.1% to 1% of a carbon black pigment, 5% to 50% of a first inorganic filler, 1% to 10% of an additive, and 10% to 40% of a first solvent, wherein the additive includes at least one of a leveling agent, a defoaming agent, and a dispersant;

[0078] The second ink composition includes the following components in percentage by mass: 5% to 20% of a thermal curing accelerator, 5% to 10% of a photopolymerizable monomer, 10% to 40% of a second epoxy resin, 10% to 20% of a stabilizer, 5% to 40% of a second inorganic filler, and 10% to 40% of a second solvent.

[0079] The ink can be cured by heating or by light.

[0080] Optionally, the mask exposure method includes UV lamp exposure or laser direct writing exposure machine (LDI exposure machine) exposure.

[0081] In some embodiments, the raw material of the prepolymer includes a low molecular weight resin containing a "C=C" unsaturated double bond.

[0082] In some embodiments, the raw material of the prepolymer includes an acrylic resin.

[0083] In some embodiments, the raw material of the prepolymer includes at least one of a polyether acrylic resin, a polypropyl acrylate, an epoxy acrylate resin, an unsaturated polyester resin, a polyurethane acrylate resin, and a polyester acrylate resin. Alternatively, the mass percentage of the prepolymer is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%. Alternatively, the mass percentage of the prepolymer may be within a range between any two of the aforementioned percentages.

[0084] In some embodiments, the first epoxy resin comprises a thermosetting resin.

[0085] In some embodiments, the first epoxy resin comprises at least one of a bisphenol A epoxy resin, a novolac epoxy resin, an alicyclic epoxy resin, and a bisphenol S epoxy resin. Optionally, the mass percentage of the first epoxy resin is 5%, 7%, 9%, 10%, 12%, 14%, 15%, 17%, 19%, or 20%. Alternatively, the mass percentage of the first epoxy resin may be within a range between any two of the aforementioned percentages.

[0086] In some embodiments, the photoinitiator includes a mixture of one or more of benzoin, acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, benzoin alkyl ethers, aminoacetophenones, benzoyl peroxide, cumyl peroxide, and benzophenone. Alternatively, the mass percentage of the photoinitiator is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. Alternatively, the mass percentage of the photoinitiator may be within a range between any two of the aforementioned percentages.

[0087] It is understood that the carbon black pigment can be any carbon black pigment commonly used in the art. Optionally, the mass percentage of the carbon black pigment is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%. Alternatively, the mass percentage of the carbon black pigment can also be within the range between any two of the above percentages.

[0088] The first inorganic filler includes at least one of magnesium carbonate, calcium carbonate, kaolin, silicon dioxide, barium sulfate, talc, clay, and aluminum oxide powder. Optionally, the mass percentage of the first inorganic filler is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. Alternatively, the mass percentage of the first inorganic filler may be within a range between any two of the aforementioned percentages.

[0089] Optionally, the mass percentage of the additive is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%. Alternatively, the mass percentage of the additive can also be within the range between any two of the above percentages.

[0090] The first solvent comprises at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethyl acetate, butyl ester, diethylene glycol monobutyl ether acetate, butanone, cyclohexanone, toluene and xylene. Optionally, the mass percentage of the first solvent is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38% or 40%. Alternatively, the mass percentage of the first solvent can also be within the range between any two of the above percentages.

[0091] The thermal curing accelerator includes at least one of dicyandiamide and its modified compounds, imidazoles and their modified compounds, organic amines, phenylguanidine, guanamine resins, thiol compounds, and amino resins. Optionally, the mass percentage of the thermal curing accelerator is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. Alternatively, the mass percentage of the thermal curing accelerator may be within a range between any two of the aforementioned percentages.

[0092] The photopolymerizable monomer includes at least one of methyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and diethylene glycol di(meth)acrylate. Optionally, the mass percentage of the photopolymerizable monomer is 5%, 6%, 7%, 8%, 9%, or 10%. Alternatively, the mass percentage of the photopolymerizable monomer may be within a range between any two of the aforementioned percentages.

[0093] The second epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol S epoxy resin, alicyclic epoxy resin, novolac epoxy resin, and biphenyl epoxy resin. Optionally, the mass percentage of the second epoxy resin is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, or 40%. Alternatively, the mass percentage of the second epoxy resin may be within a range between any two of the above percentages.

[0094] The stabilizer includes at least one of hydroquinone, p-methoxyphenol, p-benzoquinone, and 2,6-di-tert-butylcresol. Optionally, the weight percentage of the stabilizer is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. Alternatively, the weight percentage of the stabilizer may be within a range between any two of the aforementioned percentages.

[0095] The second inorganic filler includes at least one of magnesium carbonate, calcium carbonate, kaolin, silicon dioxide, barium sulfate, talc, clay, and aluminum oxide powder. Optionally, the mass percentage of the second inorganic filler is 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, or 40%. Alternatively, the mass percentage of the second inorganic filler may be within a range between any two of the aforementioned percentages.

[0096] The second solvent comprises at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethyl acetate, butyl ester, diethylene glycol monobutyl ether acetate, butanone, cyclohexanone, toluene and xylene. Optionally, the mass percentage of the second solvent is 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38% or 40%. Alternatively, the mass percentage of the second solvent can also be within the range between any two of the above percentages.

[0097] In some embodiments, the mass ratio of the first ink composition to the second ink composition in the photosensitive ink 21 is (2-5):1.

[0098] Within the range of the mass ratio of the first ink composition to the second ink composition in the photosensitive ink 21, the photosensitive ink 21 can achieve a good coating effect and ink color consistency. Optionally, the mass ratio of the first ink composition to the second ink composition in the photosensitive ink 21 is 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, or 5:1. Alternatively, the mass ratio of the first ink composition to the second ink composition in the photosensitive ink 21 can also be within a range between any two of the above mass ratios.

[0099] In some embodiments, the photosensitive ink 21 further includes open oil water, and the ratio of the mass of the open oil water to the total mass of the first ink composition and the second ink composition is 1:(8-20).

[0100] It is understood that the oil-water is a diluent used to dilute ink or coating. It can adjust the viscosity of the ink and improve its printability. Within the range of the ratio of the mass of the oil-water to the total mass of the first ink composition and the second ink composition, the photosensitive ink 21 has a suitable viscosity and a good coating effect. Optionally, the ratio of the mass of the oil-water to the total mass of the first ink composition and the second ink composition is 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, or 1:20. Alternatively, the ratio of the mass of the oil-water to the total mass of the first ink composition and the second ink composition can also be within the range between any two of the above-mentioned mass ratios.

[0101] Referring again to FIG. 1 , in some embodiments, a method for coating an LED light panel includes the following steps.

[0102] (1) An LED light board is provided, which includes a PCB substrate 12 and a lamp bead 11 arranged on the surface of the PCB substrate 12, and the lamp bead 11 has a light emitting surface and a side surface surrounding the light emitting surface.

[0103] (2) The photosensitive ink 21 is applied to the light-emitting surface and side surfaces of the lamp bead 11 and the surface of the PCB substrate 12 where the lamp bead 11 is not provided.

[0104] (3) Pre-curing the photosensitive ink 21.

[0105] (4) The photosensitive ink 21 covering the side surfaces of the lamp beads 11 and the surface of the PCB substrate 12 where the lamp beads 11 are not provided is cured by patterned mask exposure.

[0106] (5) A protective film layer 22 is prepared on the surface of the photosensitive ink 21. The material of the protective film layer 22 includes at least one of a matte agent, a waterproof coating, and a nano coating.

[0107] (6) Use an alkaline solution to clean the photosensitive ink 21 covering the light-emitting surface, and retain the photosensitive ink 21 covering the side surfaces.

[0108] (7) The remaining photosensitive ink 21 is subjected to secondary curing.

[0109] Another embodiment of the present application provides an LED light board, which is obtained by coating using any of the above-mentioned LED light board coating methods.

[0110] In some embodiments, in the LED light board, the photosensitive ink 21 covers the surface of the PCB substrate 12 where no lamp beads 11 are provided and the sides of the lamp beads 11 , and the surface of the lamp beads 11 away from the PCB substrate 12 is exposed to the photosensitive ink 21 .

[0111] In some embodiments, the upper surface of the photosensitive ink 21 is flush with the light-emitting surface of the lamp bead 11 .

[0112] In some embodiments, the upper surface of the photosensitive ink 21 is higher than the light emitting surface of the lamp bead 11 .

[0113] Example 1

[0114] LED light board coating method

[0115] (1) Provide a first ink composition and a second ink composition. The first ink composition is a main agent, which is composed of the following components in percentage by mass: 55% of o-cresol aldehyde epoxy acrylic acid copolymer, which is prepared by polymerization of o-cresol aldehyde and epoxy acrylic acid, 4% of aminoacetophenone photoinitiator, 10% of bisphenol A epoxy resin, 1% of carbon black pigment, 8% of talc powder and silica as inorganic fillers, 20% of ethylene glycol dimethyl ester and propylene glycol dimethyl ester as solvents, and 2% of defoaming agent and leveling agent. The second ink composition is a curing agent, which includes the following components in percentage by mass: 20% of polypropylene glycol diacrylate as a photopolymerization monomer, 5% of dicyandiamide as an epoxy resin thermosetting accelerator, 40% of phenolic epoxy resin, 10% of barium sulfate and calcium carbonate as inorganic fillers, and 25% of ethylene glycol dimethyl ester and propylene glycol dimethyl ester as solvents.

[0116] (2) The first ink composition, the second ink composition and the oil-water were mixed in a mass ratio of 3:1:0.2, and stirred by mechanical stirring for 10 minutes. After covering, the mixture was allowed to stand for 15 minutes to defoam.

[0117] (3) Fix the LED light board with MIP lamp beads 11 and driver IC 13 on the pre-set coating fixture, where the height of MIP lamp beads 11 is 170μm. Place the LED light board with the lamp surface facing up on the spray equipment platform, pour the rested photosensitive ink 21 into the material barrel and then automatically spray it with atomization. Set the spray thickness to 20μm.

[0118] (4) The sprayed LED light board is placed in a hot air oven, and the heating temperature is set to 75° C. and the heating time is 40 minutes to pre-cure the photosensitive ink 21.

[0119] (5) As shown in Figure 2, after the surface of the photosensitive ink 21 is pre-cured, the film with the array structure of the lamp beads 11 is symmetrically pressed onto the photosensitive ink 21 through the Mark point positioning system. Among them, the film corresponding to the MIP lamp beads 11 is painted black and opaque, and the film corresponding to the lamp slit and the PCB substrate 12 is windowed and transparent. Use UV or other methods for exposure, and the exposure energy is set to 400mJ / cm 2 The exposure time is 60s, and the film is left to stand for 10 minutes after exposure.

[0120] (6) As shown in FIG3 , after the exposure is completed, the film is removed and a solvent-volatile matte agent is sprayed on the surface of the LED light board for the second time using a sprayer with a thickness of 0.5 μm, and then heated at 75° C. for pre-curing for 15 minutes.

[0121] (7) Place the coated LED light panel with the lamp surface facing downward on an ultrasonic cleaning platform, select a sodium carbonate solution with a mass fraction of 1% as the cleaning liquid, ultrasonically clean the lamp surface for 60 seconds, and then use deionized water to clean the lamp surface for a second time to remove the film layer on the MIP lamp surface.

[0122] (8) The cleaned lamp panel is placed in a hot air oven for vacuum high-temperature curing. A step-by-step heating program is set, with the temperature rising from 80°C to 150°C, with each temperature heating time being 10 minutes, for a total heating time of 80 minutes. The photosensitive ink 21 is completely cured, and the final film thickness is measured to be 5 μm to 15 μm.

[0123] (9) When it is detected that there is residual cured photosensitive ink 21 on the surface of a certain lamp bead 11, as shown in Figure 3, a second laser cleaning of the surface of the lamp bead 11 can be performed using an ultraviolet pulse laser. The laser wavelength is 355nm, the single pulse energy is set to 20μJ, the spot size is 30μm, and the lamp surface is selectively cleaned by line scanning.

[0124] Example 2

[0125] (1) The photosensitive ink 21 used in this embodiment is the same as that used in Example 1.

[0126] (2) As shown in Figure 4, the LED light board with MIP lamp beads 11 and driver IC 13 is fixed on a pre-set screen printing fixture, where the height of the MIP lamp beads 11 is 170 μm. The LED light board is fixed on the screen printing table with the lamp surface facing up. The ink after standing is poured onto the lamp surface and screen printing is performed. The distance between the screen printing scraper and the MIP lamp surface is set to 20 μm.

[0127] (3) Place the screen-printed LED light board in a hot air oven, set the heating temperature to 75°C, and the heating time to 40 minutes.

[0128] (4) After the surface of the photosensitive ink 21 is pre-cured, the film with the array structure of the lamp beads 11 is symmetrically pressed onto the LED lamp surface through the Mark point positioning system. The film position corresponding to the MIP lamp beads 11 is painted black and opaque, and the film position corresponding to the lamp slit and the PCB substrate 12 is opened to allow light to pass through. UV exposure is used, and the exposure energy is set to 400mJ / cm 2 The exposure time is 60s, and the film is left to stand for 10min after exposure.

[0129] (5) Place the exposed LED light panel face down on an ultrasonic cleaning platform, select a 1% sodium carbonate solution as the cleaning solution, ultrasonically clean the light panel for 60 seconds, and then use deionized water to clean the light panel for a second time to remove the film layer on the MIP light panel.

[0130] (6) The cleaned lamp panel is placed in a hot air oven for vacuum high-temperature curing. A step-by-step heating program is set, with the temperature rising from 80°C to 150°C. The heating time at each temperature is set to 10 minutes, for a total heating time of 80 minutes. The photosensitive ink 21 is completely cured. As shown in FIG5 , the final lamp slit film height is measured to be approximately 175 μm to 185 μm, 5 μm to 15 μm above the lamp surface.

[0131] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0132] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make several modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the appended claims, and the specification and drawings may be used to interpret the claims.

Claims

1. A method for coating an LED lamp board, comprising: providing an LED lamp board, the LED lamp board including a PCB substrate and lamp beads disposed on the surface of the PCB substrate, the lamp beads having a light-emitting surface and a side surface surrounding the light-emitting surface; coating photosensitive ink on the light-emitting surface, the side surface of the lamp beads, and the surface of the PCB substrate where no lamp beads are disposed; performing patterned mask exposure on the photosensitive ink to remove the photosensitive ink covering the light-emitting surface and retain the photosensitive ink covering the side surface.

2. The method for coating an LED light board according to claim 1, wherein, Before performing the patterned mask exposure on the photosensitive ink, it further includes: pre-curing the photosensitive ink.

3. The method for coating an LED light board according to claim 2, wherein, The temperature of the pre-curing is 60°C to 90°C; and / or, The time of the pre-curing is 15 min to 40 min.

4. The LED lamp board coating method according to claim 3, wherein, The temperature of the pre-curing is 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C, 84°C, 86°C, 88°C or 90°C.

5. The LED lamp board coating method according to claim 3 or 4, wherein The time of the pre-curing is 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, 32 min, 35 min, 38 min or 40 min.

6. The method for coating an LED light board according to claim 1, wherein, After removing the photosensitive ink covering the light-emitting surface and retaining the photosensitive ink covering the side surface, it further includes: performing secondary curing on the remaining photosensitive ink.

7. The method for coating an LED lamp board according to claim 6, wherein, The temperature of the secondary curing is 80°C to 150°C; and / or, The time of the secondary curing is 30 min to 120 min.

8. The LED lamp board coating method according to claim 7, wherein, The temperature of the secondary curing is 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C.

9. The LED light board coating method according to claim 7 or 8, wherein The time of the secondary curing is 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min.

10. The LED light board coating method according to any one of claims 1 to 9, wherein, Performing patterned mask exposure on the photosensitive ink to remove the photosensitive ink covering the light-emitting surface and retain the photosensitive ink covering the side surface includes: curing the photosensitive ink covering the side surface and the surface of the PCB substrate where no lamp beads are disposed through patterned mask exposure; cleaning the photosensitive ink covering the light-emitting surface with an alkaline solution.

11. The method for coating an LED light board according to claim 10, wherein, The energy of the mask exposure is 200 mJ / cm 2 ~500 mJ / cm 2 .

12. The LED lamp board coating method according to claim 11, wherein, The energy of the mask exposure is 200 mJ / cm 2 , 250 mJ / cm 2 , 300 mJ / cm 2 , 350 mJ / cm 2 , 400 mJ / cm 2 , 450 mJ / cm 2 or 500 mJ / cm 2 .

13. The method for coating an LED light board according to any one of claims 10 to 12, wherein, The time of the exposure is 30 s to 60 s.

14. The LED lamp board coating method according to claim 13, wherein, The time of the exposure is 30 s, 35 s, 40 s, 45 s, 50 s, 55 s or 60 s.

15. The method for coating an LED lamp board according to any one of claims 10 to 14, wherein, The alkaline solution includes at least one of a sodium carbonate solution and a sodium bicarbonate solution.

16. The method for coating an LED lamp board according to any one of claims 10 to 15, wherein, The mass percentage concentration of the alkaline solution is 0.5% to 2%.

17. The method for coating an LED light board according to any one of claims 16, wherein, The mass percentage concentration of the alkaline solution is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%.

18. The method for coating an LED lamp board according to any one of claims 10 to 17, wherein, The time of the cleaning is 30 s to 120 s.

19. The LED lamp board coating method according to claim 18, wherein, The cleaning time is 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s or 120s.

20. The method for coating an LED light board according to any one of claims 1 to 19, wherein, Before performing patterning mask exposure on the photosensitive ink, it further includes: Preparing a protective film layer on the photosensitive ink, and the material of the protective film layer includes at least one of a matting agent, a waterproof coating, and a nano - coating.

21. The method for coating an LED light board according to any one of claims 6 to 20, wherein, After performing secondary curing on the remaining photosensitive ink, it further includes: Performing a second cleaning on the light - emitting surface.

22. The LED light board coating method according to claim 21, wherein, The second cleaning includes at least one of plasma cleaning and laser cleaning, and the laser cleaning includes ultraviolet pulsed laser cleaning.

23. The method for coating an LED light board according to any one of claims 1 to 22, wherein, The photosensitive ink includes a first ink composition and a second ink composition; The first ink composition includes the following components in mass percentages: 20% - 70% of a prepolymer, 5% - 20% of a first epoxy resin, 1% - 10% of a photoinitiator, 0.1% - 1% of a carbon black pigment, 5% - 50% of a first inorganic filler, 1% - 10% of an additive, and 10% - 40% of a first solvent, and the additive includes at least one of a leveling agent, an antifoaming agent, and a dispersant; The second ink composition includes the following components in mass percentages: 5% - 20% of a thermal curing accelerator, 5% - 10% of a photopolymerizable monomer, 10% - 40% of a second epoxy resin, 10% - 20% of a stabilizer, 5% - 40% of a second inorganic filler, and 10% - 40% of a second solvent.

24. The LED lamp panel coating method according to claim 23, wherein, The mass ratio of the first ink composition to the second ink composition in the photosensitive ink is (2 - 5):1; and / or, The photosensitive ink further includes thinner, and the mass ratio of the thinner to the total mass of the first ink composition and the second ink composition is 1:(8 - 20).

25. An LED light board, which is coated by using the LED light board coating method according to any one of claims 1 - 24.

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