Flip COB full-color unit and coating tool for preparing side edge coating thereof

Abstract

The present application relates to a kind of flip COB full-color unit and preparation its side coating coating tool, the surface periphery side of the protective film and epoxy resin layer of the COB full-color unit is prepared with coating;Coating is the mixture of gray solid pigment and acrylic resin;Coating tool includes oblique coating tool and parallel coating tool;In oblique coating tool, first coating pen is fixed on the moving part of first linear displacement mechanism with 45 ° inclination, and the pen tip section can be attached to the side of full-color unit protective film and move linearly;In parallel coating tool, second coating pen is vertically fixed on the moving part of second linear displacement mechanism, and the pen tip cylinder can be attached to the side of full-color unit epoxy resin layer and protective film and move linearly in deep groove.The present application can achieve the effect of eliminating the abnormality of gap brightness between flip COB full-color unit.

Description

Technical Field

[0001] This invention belongs to the technical field of flip-chip COB full-color cells, and relates to a flip-chip COB full-color cell and a coating tooling for preparing its side coating. Background Technology

[0002] In a flip-chip COB full-color unit, the R, G, and B chips inside the package are arranged in a straight line. Above the chips is a layer of epoxy resin of uniform thickness, and a PVC film is adhered to the outside of the epoxy resin layer. When the three colors of light pass through the PVC film, refraction occurs, resulting in a softer brightness. However, there are certain gaps between flip-chip COB full-color units, and due to the immature cutting technology of the PVC film at the corners of the full-color units, some of the three colors of light are reflected after hitting the epoxy resin layer. This resulting high brightness significantly affects the display effect when flip-chip COB full-color units are spliced ​​into modules, such as... Figure 1 , Figure 2 As shown, this significantly impacts the customer experience. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an inverted COB full-color cell that can eliminate the abnormal brightness of the gap between inverted COB full-color cells and a coating tool for preparing its side coating.

[0004] To solve the above-mentioned technical problems, the present invention provides a flip-chip COB full-color unit in which a chip array is arranged on a circuit board, an epoxy resin layer covers the circuit board and the chip array, and a protective film is pasted on the surface of the epoxy resin layer. The protective film and the periphery of the epoxy resin layer are characterized by coatings formed on the sides; the coatings formed on the periphery of the protective film consist of a first coating and a second coating applied to the surface of the first coating; the coatings formed on the periphery of the epoxy resin layer consist of the second coating; the first coating is a mixture of gray solid pigment and acrylic resin in a weight ratio of (16-21):(10-15), and the second coating is a mixture of gray solid pigment and acrylic resin in a weight ratio of (14-19):(12-17).

[0005] Preferably, the weight ratio of gray solid pigment to acrylic resin in the first coating is (20-21):(10-11), and the weight ratio of gray solid pigment to acrylic resin in the second coating is (18-19):(12-13).

[0006] Preferably, the weight ratio of gray solid pigment to acrylic resin in the first coating is (16-17):(14-15), and the weight ratio of gray solid pigment to acrylic resin in the second coating is (18-19):(12-13).

[0007] Preferably, the weight ratio of gray solid pigment to acrylic resin in the first coating is (20-21):(10-11), and the weight ratio of gray solid pigment to acrylic resin in the second coating is (14-15):(16-17).

[0008] Furthermore, the coating fixture for preparing the side coating of the above-mentioned inverted COB full-color unit includes an inclined coating fixture and a parallel coating fixture; the inclined coating fixture includes a first working platform, a first linear displacement mechanism, and a first coating pen; the first linear displacement mechanism is disposed on the first working platform, and the first coating pen is fixed at a 45° angle to the moving part of the first linear displacement mechanism, and the full-color unit can be partially embedded in the groove structure of the first working platform; the 45° tip cut surface of the first coating pen can conform to the side of the protective film of the full-color unit and move linearly; the parallel coating fixture includes a second working platform, a second linear displacement mechanism, and a second coating pen; the second linear displacement mechanism is disposed on the second working platform, and the second coating pen is vertically fixed to the moving part of the second linear displacement mechanism, and the full-color unit can be embedded in the groove structure of the second working platform with the protective film facing downward; the cylindrical tip of the second coating pen can conform to the side of the epoxy resin layer and the protective film of the full-color unit and move linearly in the deep groove.

[0009] The groove structure of the first working platform includes a horizontal groove A and a vertical groove A, which can be used to embed two full-color units into the horizontal groove A and the vertical groove A respectively.

[0010] The tilting coating fixture further includes a first connecting plate, a first clamp, a first connector, and a first fine-tuning rod. The first connecting plate is fixed to the moving part of the first linear displacement mechanism. The first clamp is mounted on the first connecting plate via a slide rail pair and can be locked in place by a locking nut. The first coating pen is clamped and fixed to the first clamp at a 45° angle. The first connector is fixed to the first clamp. The first fine-tuning rod is fixed to the first connecting plate via a threaded connector, and its front end abuts against the side of the first connector. Rotating the first fine-tuning rod can push the first clamp to move through the first connector, thereby causing the tip of the first coating pen to contact the side surface of the full-color unit protective film.

[0011] The groove structure of the second working platform includes a horizontal groove (B) and a vertical groove (B), which can embed two full-color units into the horizontal groove (B) and the vertical groove (B) respectively. The second working platform has a horizontal deep groove, and the cylindrical surface of the tip of the second coating pen can move linearly in the deep groove while adhering to the side of the epoxy resin layer and protective film of the full-color unit.

[0012] The parallel coating fixture further includes a second connecting plate, a second clamp, a second connector, and a second fine-tuning rod. The second connecting plate is fixed to the moving part of the second linear displacement mechanism. The second clamp is mounted on the second connecting plate via a slide rail pair and can be locked in place by a locking nut. The second coating pen is vertically clamped and fixed on the second clamp. The second connector is fixed on the second clamp. The second fine-tuning rod is fixed to the second connecting plate via a threaded connector, and its front end abuts against the side of the second connector. By rotating the second fine-tuning rod, the second clamp can be moved through the second connector, thereby causing the cylindrical tip of the second coating pen to contact the side surface of the full-color unit.

[0013] The method for preparing the protective film and the epoxy resin layer peripheral side coating using the above coating tooling is as follows:

[0014] 1. Place the two full-color unit protective films facing upwards into the horizontal groove A and the vertical groove A of the inclined coating fixture, respectively.

[0015] 2. Fill the pen holder of the first coating pen with an alcoholic solvent in a weight ratio of (16-21):(68-70):(10-15) of gray solid pigment, denatured alcohol, and acrylic resin; rotate the first fine-tuning rod to push the first clamp to move through the first connector, so that the tip of the first coating pen contacts one side of the full-color unit protective film; the moving part of the first linear displacement mechanism moves linearly, causing the first coating pen and the first clamp to move together, and the tip of the pen applies the alcoholic solvent to one side of the two full-color unit protective films. After the alcoholic solvent dries, apply another layer, and after drying again, form the first coating layer on the side of the protective film; rotate the two full-color units 180° and prepare the first coating layer on the opposite side of the protective film using the same method; swap the positions of the two full-color units and prepare the first coating layer on the other two sides of the protective film using the same method; manually apply the alcoholic solvent to the four corners of the protective film and then let it air dry, for a total of three times;

[0016] 3. The pen barrel of the second coating pen 23 is filled with an alcoholic solvent in a weight ratio of (14-19):(68-70):(12-17) of gray solid pigment, denatured alcohol, and acrylic resin. The second fine-tuning rod is rotated to push the second clamp to move through the second connector, so that the cylindrical tip of the second coating pen contacts one side of the protective film and epoxy resin layer. The second coating pen and the second clamp move linearly together with the moving parts of the second linear displacement mechanism. The cylindrical tip moves along the deep groove to coat the alcoholic solvent onto one side of the protective film and epoxy resin layer of the two full-color units. After the alcoholic solvent dries, it is coated again. After drying again, a second coating is formed on the surface of the first coating and the side of the epoxy resin layer. The two full-color units are rotated 180° and the second coating is prepared on the opposite side of the protective film and epoxy resin layer using the same method. The positions of the two full-color units are swapped, and the second coating is prepared on the other two sides of the epoxy resin layer using the same method. The alcoholic solvent B is manually applied to the four corners of the epoxy resin layer and then dried. This process is repeated three times.

[0017] This invention achieves the effect of eliminating abnormal brightness in the gaps between flip-chip COB full-color units by coating the peripheral sides of the full-color unit with a mixture of gray solid pigment, denatured alcohol and acrylic resin to block the light emitted by the light-emitting chip. Attached Figure Description

[0018] Figure 1 These are images showing the display effect of an existing inverted COB full-color unit splicing module.

[0019] Figure 2 This is an image showing the display effect at the corners of the full-color units when using an existing inverted COB full-color unit splicing module.

[0020] Figure 3 This is a top view of the inclined coating fixture structure.

[0021] Figure 4 It is a 3D view of the inclined coating tooling structure.

[0022] Figure 5 This is a 3D view of the parallel coating tooling structure.

[0023] Figure 6 This is a top view of the parallel coating fixture structure.

[0024] Figure 7 This is a front view of the parallel coating fixture structure.

[0025] Figure 8 , Figure 9 , Figure 10 These are the module display effect diagrams of full-color unit splicing after coating of Examples 1-1, 2-3, and 3-1.

[0026] In the figure: 11. First working platform; 111. A transverse groove; 112. A longitudinal groove; 12. First linear displacement mechanism; 13. First coating pen; 131. Pen tip cross-section; 14. First connecting plate; 15. First clamp; 16. First connector; 17. First fine-tuning rod; 18. Locking nut; 21. Second working platform; 211. B transverse groove; 212. B longitudinal groove; 213. Deep groove; 22. Second linear displacement mechanism; 23. Second coating pen; 231. Pen tip cylindrical surface; 24. Second connecting plate; 25. Second clamp; 26. Second connector; 27. Second fine-tuning rod; 28. Locking nut. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the drawings, not the entire structure.

[0028] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0031] Existing flip-chip COB full-color cells have a chip array arranged on a circuit board, an epoxy resin layer covering the circuit board and the chip array, and a protective film adhered to the surface of the epoxy resin layer. This invention prepares a coating with a total thickness of 0.005-0.015 mm on the peripheral sides of the protective film and the epoxy resin layer. The coating prepared on the peripheral sides of the protective film consists of a first coating and a second coating applied to the surface of the first coating. The coating prepared on the peripheral sides of the epoxy resin layer consists of the second coating. Both the first and second coatings are mixtures of gray solid pigment and acrylic resin, prepared using a coating tooling.

[0032] The coating fixtures include inclined coating fixtures and parallel coating fixtures.

[0033] like Figure 3 , 4 As shown, the inclined coating fixture includes a first working platform 11, a first linear displacement mechanism 12, a first coating pen 13, a first connecting plate 14, a first clamp 15, a first connector 16, and a first fine-tuning rod 17.

[0034] The first working platform 11 has a groove structure for placing full-color units. When the full-color unit is square, the groove structure can be a groove that can only hold one full-color unit, or it can be a groove that can hold multiple full-color units side by side. When the full-color unit is rectangular, the groove structure includes a transverse groove 111 and a longitudinal groove 112. The two full-color units are embedded in the transverse groove 111 and the longitudinal groove 112 respectively with their protective films facing upwards, as long as the protective films of the full-color units are higher than the upper surface of the first working platform 11. The first linear displacement mechanism 12 is located on one side of the first working platform 11 and can be a rodless cylinder or other existing linear displacement mechanisms. The moving part of the rodless cylinder moves parallel to the transverse side of the transverse groove 111. The first connecting plate 14 is fixed on the moving part of the rodless cylinder. The first clamp 15 is mounted on the first connecting plate 14 through a slide rail pair and can be locked and fixed by a locking nut 18. The first coating pen 13 is clamped and fixed at a 45° angle on the first clamp 15, and the 45° tip cut surface 131 of the first coating pen 13 is parallel to the side of the full-color unit; the first connector 16 is fixed on the first clamp 15; the first fine-tuning rod 17 is fixed on the first connecting plate 14 through a threaded connector and its front end abuts against the side of the first connector 16. Rotating the first fine-tuning rod 17 can push the first clamp 15 to move through the first connector 16, so that the tip cut surface 131 of the first coating pen 13 contacts the side of the protective film of the full-color unit; the tip of the first coating pen 13 is made of fiber.

[0035] like Figure 5 , 6As shown, the parallel coating fixture includes a second working platform 21, a second linear displacement mechanism 22, a second coating pen 23, a second connecting plate 24, a second clamp 25, a second connector 26, and a second fine-tuning rod 27.

[0036] The second working platform 21 has a groove structure for placing full-color units. When the full-color unit is square, the groove structure can be a groove that can only hold one full-color unit, or it can hold multiple full-color units side by side. When the full-color unit is rectangular, the groove structure includes a B-shaped horizontal groove 211 and a B-shaped vertical groove 212. The second working platform 21 also has a horizontal deep groove 213. The tip cylindrical surface 231 of the second coating pen 23 can conform to the side of the epoxy resin layer and protective film of the full-color unit and move linearly within the deep groove 213. The two full-color units can be embedded in the B-shaped horizontal groove 211 and the B-shaped vertical groove 212 respectively with the protective film facing down. The second linear displacement mechanism 22 is set on one side of the second working platform 21 and adopts a rodless cylinder or other existing linear displacement mechanism. The rodless cylinder operates... The moving part moves in a direction parallel to the transverse side of the B transverse groove 211. The second connecting plate 24 is fixed on the moving part of the rodless cylinder. The second clamp 25 is mounted on the second connecting plate 24 via a slide rail pair and can be locked and fixed by a locking nut 28. The second coating pen 23 is vertically clamped and fixed on the second clamp 25. The tip of the second coating pen 23 is located in the deep groove 213 and its tip cylindrical surface 231 is parallel to the side of the full-color unit. The second connector 26 is fixed on the second clamp 25. The second fine-tuning rod 27 is fixed on the second connecting plate 24 via a threaded connector and its front end abuts against the side of the second connector 26. Rotating the second fine-tuning rod 27 can push the second clamp 25 to move through the second connector 26, thereby making the tip cylindrical surface 231 of the second coating pen 23 contact the side of the full-color unit. The tip of the second coating pen 23 is made of fiber.

[0037] Example 1

[0038] The method for preparing the peripheral side coating of the protective film and epoxy resin layer is as follows:

[0039] 1. Place the two full-color unit protective films face up into the horizontal groove 111 and the vertical groove 112 of the inclined coating fixture, respectively.

[0040] 2. The first coating pen 13 is filled with alcoholic solvent A, and the weight ratio of gray solid pigment, denatured alcohol, and acrylic resin in alcoholic solvent A is (20-21):(68-70):(10-11); the first fine-tuning rod 17 is rotated to push the first clamp 15 to move through the first connector 16, so that the tip cut surface 131 of the first coating pen 13 contacts one side of the full-color unit protective film; the first coating pen 13 and the first clamp 15 move together with the first linear displacement mechanism 12. The moving part moves linearly, and the pen tip cut surface 131 applies alcoholic solvent A to one side of the protective film of the full-color unit. After the alcoholic solvent A dries, it is applied again and dried again to form the first coating on the side of the protective film. The two full-color units are rotated 180° and the first coating is prepared on the opposite side of the protective film using the same method. The two full-color units are swapped and the first coating is prepared on the other two sides of the protective film using the same method. The alcoholic solvent A is manually applied to the four corners of the protective film and then dried, for a total of three times.

[0041] 3. The pen barrel of the second coating pen 23 is filled with alcoholic solvent B, and the weight ratio of gray solid pigment, denatured alcohol, and acrylic resin in alcoholic solvent B is (18-19):(68-70):(12-13); the second fine-tuning rod 27 is rotated to push the second clamp 25 to move through the second connector 26, so that the pen tip cylindrical surface 231 of the second coating pen 23 contacts one side of the full-color unit protective film and epoxy resin layer; the second coating pen 23 and the second clamp 25 move linearly together with the moving parts of the second linear displacement mechanism 22, and the pen tip cylindrical surface 231 moves along... The deep groove 213 moves to coat the surface of the first coating layer of the protective film and the side of the epoxy resin layer with alcoholic solvent B. After the alcoholic solvent B dries, it is coated again and dried again to form a second coating layer on the surface of the first coating layer and the side of the epoxy resin layer. The two full-color units are rotated 180° and the second coating layer is prepared on the opposite side of the protective film and the epoxy resin layer using the same method. The two full-color units are swapped and the second coating layer is prepared on the other two side of the protective film and the epoxy resin layer using the same method. The alcoholic solvent B is manually applied to the four corners of the epoxy resin layer and then dried, for a total of three times.

[0042] Example 2

[0043] The difference between this embodiment and embodiment 1 is that the pen barrel of the first coating pen 13 is filled with an alcoholic solvent C, and the weight ratio of gray solid pigment, denatured alcohol and acrylic resin in the alcoholic solvent is (16-17):(68-70):(14-15).

[0044] Example 3

[0045] The difference between this embodiment and embodiment 1 is that the pen barrel of the second coating pen 13 is filled with alcoholic solvent D, and the weight ratio of gray solid pigment, denatured alcohol and acrylic resin in alcoholic solvent D is (14-15):(68-70):(16-17).

[0046] The weights of gray solid pigment, denatured alcohol, and acrylic resin, the thickness of the peripheral side coating of the protective film and epoxy resin layer, and the display effect of the gaps between COB full-color units in each embodiment are shown in Table 1.

[0047] Table 1

[0048]

Claims

1. A flip-chip COB full-color unit, wherein a chip array is arranged on a circuit board, an epoxy resin layer covers the circuit board and the chip array, and a protective film is adhered to the surface of the epoxy resin layer, characterized in that... The protective film and epoxy resin layer are coated with a coating on their peripheral sides; the coating on the peripheral sides of the protective film consists of a first coating and a second coating applied to the surface of the first coating; the coating on the peripheral sides of the epoxy resin layer consists of the second coating; the first coating is a mixture of gray solid pigment and acrylic resin in a weight ratio of (16-21):(10-15), and the second coating is a mixture of gray solid pigment and acrylic resin in a weight ratio of (14-19):(12-17).

2. The flip-chip COB full-color unit according to claim 1, characterized in that... The weight ratio of gray solid pigment to acrylic resin in the first coating is (20-21):(10-11), and the weight ratio of gray solid pigment to acrylic resin in the second coating is (18-19):(12-13).

3. The flip-chip COB full-color unit according to claim 1, characterized in that... The weight ratio of gray solid pigment to acrylic resin in the first coating is (16-17):(14-15), and the weight ratio of gray solid pigment to acrylic resin in the second coating is (18-19):(12-13).

4. The flip-chip COB full-color unit according to claim 1, characterized in that... The weight ratio of gray solid pigment to acrylic resin in the first coating is (20-21):(10-11), and the weight ratio of gray solid pigment to acrylic resin in the second coating is (14-15):(16-17).

5. A coating tooling for preparing the side coating of the inverted COB full-color unit as described in claim 1, characterized in that... The fixture includes an inclined coating fixture and a parallel coating fixture. The inclined coating fixture includes a first working platform (11), a first linear displacement mechanism (12), and a first coating pen (13). The first linear displacement mechanism is set on the first working platform, and the first coating pen is fixed at a 45° angle to the moving part of the first linear displacement mechanism. The full-color unit can be partially embedded in the groove structure of the first working platform. The 45° tip cut surface (131) of the first coating pen can conform to the side of the protective film of the full-color unit and move linearly. The parallel coating fixture includes a second working platform (21), a second linear displacement mechanism (22), and a second coating pen (23). The second linear displacement mechanism is set on the second working platform, and the second coating pen is fixed vertically to the moving part of the second linear displacement mechanism. The full-color unit can be embedded in the groove structure of the second working platform with the protective film facing down. The tip cylindrical surface (231) of the second coating pen can conform to the side of the epoxy resin layer and the protective film of the full-color unit and move linearly in the deep groove (213).

6. The coating fixture for preparing the side coating of the inverted COB full-color unit as described in claim 1, as described in claim 5, is characterized in that... The groove structure of the first working platform includes a horizontal groove (111) and a vertical groove (112), which can embed two full-color units into the horizontal groove and the vertical groove respectively.

7. The coating tooling for preparing the side coating of the inverted COB full-color unit as described in claim 1, according to claim 6, is characterized in that... The tilting coating fixture also includes a first connecting plate (14), a first clamp (15), a first connector (16), and a first fine-tuning rod (17). The first connecting plate is fixed on the moving part of the first linear displacement mechanism. The first clamp is mounted on the first connecting plate via a slide rail pair and can be locked and fixed by a locking nut. The first coating pen is clamped and fixed on the first clamp at a 45° angle. The first connector is fixed on the first clamp. The first fine-tuning rod is fixed on the first connecting plate via a threaded connector and its front end abuts against the side of the first connector. Rotating the first fine-tuning rod can push the first clamp to move through the first connector, thereby making the pen tip of the first coating pen contact the side surface of the full-color unit protective film.

8. The coating fixture for preparing the side coating of the inverted COB full-color unit as described in claim 1, according to claim 7, is characterized in that... The groove structure of the second working platform includes a horizontal groove (211) and a vertical groove (212), which can embed two full-color units into the horizontal groove and the vertical groove respectively; the second working platform has a horizontal deep groove (213), and the cylindrical surface of the tip of the second coating pen can conform to the side of the epoxy resin layer and protective film of the full-color unit and move linearly in the deep groove.

9. The coating tooling for preparing the side coating of the flip-chip COB full-color unit as described in claim 1, as described in claim 8, is characterized in that... The parallel coating fixture also includes a second connecting plate (24), a second clamp (25), a second connector (26), and a second fine-tuning rod (27). The second connecting plate is fixed on the moving part of the second linear displacement mechanism. The second clamp is mounted on the second connecting plate via a slide rail pair and can be locked and fixed by a locking nut. The second coating pen is vertically clamped and fixed on the second clamp. The second connector is fixed on the second clamp. The second fine-tuning rod is fixed on the second connecting plate via a threaded connector and its front end abuts against the side of the second connector. By rotating the second fine-tuning rod, the second clamp can be moved through the second connector, thereby making the cylindrical surface of the pen tip of the second coating pen contact the side surface of the full-color unit.

10. A method for preparing a protective film and an epoxy resin layer peripheral side coating using the coating fixture as described in claim 9, characterized in that... The method includes the following steps:

1. Place the two full-color unit protective films facing upwards into the horizontal groove A and the vertical groove A of the inclined coating fixture, respectively.

2. Fill the pen holder of the first coating pen with an alcoholic solvent A in a weight ratio of (16-21):(68-70):(10-15) of gray solid pigment, denatured alcohol, and acrylic resin; rotate the first fine-tuning rod to push the first clamp to move through the first connector, so that the pen tip of the first coating pen contacts one side of the full-color unit protective film; the moving part of the first linear displacement mechanism moves linearly, causing the first coating pen and the first clamp to move together, and the pen tip applies the alcoholic solvent A to one side of the two full-color unit protective films. After the alcoholic solvent A dries, apply another layer, and after it dries again, a first coating layer is formed on the side of the protective film; rotate the two full-color units 180° and prepare the first coating layer on the opposite side of the protective film using the same method; swap the positions of the two full-color units and prepare the first coating layer on the other two sides of the protective film using the same method. Apply alcohol-based solvent A to the four corners of the protective film manually, then air dry, repeating this process three times.

3. The pen barrel of the second coating pen (23) is filled with an alcoholic solvent B in a weight ratio of gray solid pigment, denatured alcohol and acrylic resin of (14-19): (68-70): (12-17); the second fine-tuning rod is rotated to push the second clamp to move through the second connector, so that the pen tip of the second coating pen contacts one side of the protective film and epoxy resin layer; the second coating pen and the second clamp move together with the moving parts of the second linear displacement mechanism, and the pen tip moves along the deep groove to coat the alcoholic solvent B onto one side of the two full-color unit protective films and epoxy resin layers. After the alcoholic solvent B dries, it is coated again, and after drying again, a second coating is formed on the surface of the first coating layer and the side of the epoxy resin layer. Rotate the two full-color units 180° and use the same method to prepare the second coating on the opposite sides of the protective film and epoxy resin layer; swap the positions of the two full-color units and use the same method to prepare the second coating on the other two sides of the epoxy resin layer. Apply alcoholic solvent B manually to the four corners of the epoxy resin layer, then air dry, for a total of three times.

Images