Preparation method of circuit board

Abstract

The invention provides a preparation method of a circuit board. The preparation method comprises the following steps: coating a substrate with imprinting glue; an imprint mold is provided, the imprint mold is provided with a first imprint structure corresponding to the target conductive circuit and a second imprint structure corresponding to the target virtual structure, and the first imprint structure and the second imprint structure are arranged at an interval; coining the coining glue by adopting a coining mold, separating the coining mold after the coining glue is cured, and forming a conductive groove corresponding to the first coining structure and a non-conductive groove corresponding to the second coining structure on the coining glue; filling a conductive material in the conductive groove to form a conductive circuit, and filling a conductive material in the non-conductive groove to form a virtual structure; according to the circuit board, the demolding yield can be improved, the duty ratio of the circuit area and the non-circuit area in the conducting layer can be reduced, and the color difference uniformity of the whole circuit board is good.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and in particular to a method for preparing a circuit board. Background Art

[0002] With the development of display technology, mini LED display devices have gradually become the trend of high-end display devices due to their advantages of high contrast, high brightness, and local dimming. At present, the preparation method of mini LED circuit boards is mainly through exposure-development-etching and other processes to remove unnecessary copper on the substrate to form a conductive circuit (conductive layer). The production cost is high and the process is relatively cumbersome.

[0003] Some existing circuit boards are prepared by printing thin films, that is, first coating a layer of UV glue or embossed glue on the substrate, and then attaching the mold to the substrate. The mold is only provided with an embossed structure at the position corresponding to the target conductive circuit. After curing and demolding, the embossed structure forms a conductive groove on the UV glue or embossed glue, and finally a conductive material is deposited in the conductive groove to form a conductive circuit. The preparation method is simple. However, due to the large difference in duty cycle between the circuit area and the non-circuit area (i.e., the area other than the conductive groove), the demolding stress is greatly different, the demolding yield is low, and the overall color difference of the final circuit board is large. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a circuit board.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a method for preparing a circuit board, comprising the following steps:

[0006] Applying embossing glue on the substrate;

[0007] Providing an imprinting mold, wherein the imprinting mold is provided with a first imprinting structure corresponding to a target conductive circuit and a second imprinting structure corresponding to a target virtual structure, wherein the first imprinting structure and the second imprinting structure are arranged at an interval;

[0008] Imprinting the embossing adhesive using an imprinting mold, separating the imprinting mold after the embossing adhesive is solidified, and forming a conductive groove corresponding to the first imprinting structure and a non-conductive groove corresponding to the second imprinting structure on the embossing adhesive;

[0009] The conductive groove is filled with a conductive material to form a conductive circuit, and the non-conductive groove is filled with a conductive material to form a dummy structure.

[0010] As a further improved technical solution of the present invention, the embossing adhesive is a light-curing adhesive or a heat-curing adhesive.

[0011] As a further improved technical solution of the present invention, the conductive material is copper.

[0012] As a further improved technical solution of the present invention, the distance between the second embossing structure and the first embossing structure is 0.2 mm to 2 mm.

[0013] As a further improved technical solution of the present invention, the second embossing structures are arranged at intervals on the circumference of the first embossing structure.

[0014] As a further improved technical solution of the present invention, the imprinting mold includes a substrate, the substrate has a first surface, the first surface has a conductive groove molding area for forming the conductive groove, and a non-conductive molding area located around the conductive groove molding area, the first imprinting structure covers the conductive groove molding area; the non-conductive molding area has a spacing area located on the peripheral side of the first imprinting structure and extending along the extension direction of the first imprinting structure, and the non-conductive molding areas except the spacing area are all provided with the second imprinting structure.

[0015] As a further improved technical solution of the present invention, the second imprinted structure is a strip-shaped structure extending along the extension direction of the first imprinted structure on the peripheral side of the first imprinted structure.

[0016] As a further improved technical solution of the present invention, the width of the second embossing structure is 0.2 mm to 20 mm.

[0017] As a further improved technical solution of the present invention, the second embossing structure includes a plurality of annular annular embossing structures.

[0018] As a further improved technical solution of the present invention, the protrusion heights of the first embossing structure and the second embossing structure are the same.

[0019] The beneficial effects of the present invention are as follows: in the method for preparing a circuit board of the present invention, by adding a second imprinting structure in the imprinting mold, after the imprinting mold imprints the imprinting glue, a non-conductive groove is also added to the non-conductive area in the imprinting glue to form a non-conductive groove, which can reduce the duty ratio of the groove area and the non-groove area in the imprinting glue, so that when the imprinting glue is cured to form a polymer and the imprinting mold is separated, that is, when demolding, the demolding stress of the entire surface can be made more balanced, the size of the entire sheet is less affected, and the demolding yield can be improved; at the same time, the non-conductive area in the circuit board finally prepared is also added with a virtual structure that does not have a conductive effect, which can reduce the duty ratio of the line area and the non-line area in the conductive layer of the formed circuit board, so that the overall color difference uniformity of the circuit board is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1is a flow chart of preparing a circuit board using the imprinting mold in the first embodiment of the present invention;

[0021] Figure 2 yes Figure 1 A schematic diagram of the structure of the conductive layer in the prepared circuit board;

[0022] Figure 3 is a flow chart of preparing a circuit board using the imprinting mold in the second embodiment of the present invention;

[0023] Figure 4 yes Figure 3 Schematic diagram of the structure of the conductive layer in the prepared circuit board. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below in conjunction with the various embodiments shown in the accompanying drawings. Figures 1 to 4 It is shown as a preferred embodiment of the present invention. However, it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformation or replacement of functions, methods, or structures made by ordinary technicians in the field according to these embodiments shall fall within the protection scope of the present invention.

[0025] Please refer to Figure 1 As shown, the present invention provides a method for preparing a circuit board 10, comprising the following steps:

[0026] Coating an embossing adhesive 3 on the substrate 1;

[0027] Providing an imprinting mold 20, wherein the imprinting mold 20 is provided with a first imprinting structure 5 corresponding to a target conductive circuit and a second imprinting structure 6 corresponding to a target virtual structure, wherein the first imprinting structure 5 and the second imprinting structure 6 are arranged at an interval;

[0028] The embossing adhesive 3 is embossed by using an embossing mold 20. After the embossing adhesive 3 is cured and the embossing mold 20 is separated, a conductive groove 31 corresponding to the first embossing structure 5 and a non-conductive groove 32 corresponding to the second embossing structure 6 are formed on the embossing adhesive 3.

[0029] The conductive groove 31 is filled with a conductive material to form a conductive circuit 21 , and the non-conductive groove 32 is filled with a conductive material to form a dummy structure 22 .

[0030] In the present invention, by adding a second stamping structure 6 for forming a non-conductive groove 32 for accommodating a dummy circuit on the stamping mold 20, after the stamping mold 20 stamps the stamping glue 3, the duty ratio of the groove area and the non-groove area in the stamping glue 3 can be reduced, so that when the stamping glue 3 is cured to form a polymer 23 and the stamping mold 20 is separated, that is, when demolding, the demolding stress of the entire surface can be made more balanced, the effect on the size of the entire sheet is small, and the demolding yield can be improved; at the same time, the duty ratio of the line area and the non-line area in the conductive layer 2 in the finally formed circuit board 10 can also be reduced, so that the overall color difference uniformity of the circuit board 10 is better.

[0031] It should be noted that the above-mentioned line area refers to the area of ​​the conductive line 21 and the dummy structure 22, and the above-mentioned non-line area refers to the area of ​​the polymer 23. The above-mentioned groove area refers to the area of ​​the polymer 23 corresponding to the conductive groove 31 and the non-conductive groove 32, and the above-mentioned non-groove area refers to the area of ​​the polymer 23. The above-mentioned groove area in the embossed glue 3 refers to the area of ​​the conductive groove 31 and the non-conductive groove 32 in the embossed glue 3, and the above-mentioned non-groove area in the embossed glue 3 refers to the other areas of the embossed glue 3 except the groove area.

[0032] In a specific embodiment, the embossed adhesive 3 is a photocurable adhesive. The corresponding polymer 23 is a photocurable adhesive after light curing, which can improve the stability of the shape / size of the formed conductive groove 31 and the non-conductive groove 32, is conducive to the linearity / size control of the conductive line 21 / dummy structure 22, and improves the stability of the circuit board 10. Of course, it is not limited to this. In other embodiments, the embossed adhesive 3 can also be a thermal curable adhesive.

[0033] Furthermore, the conductive material is copper, that is, the conductive line 21 and the dummy structure 22 are both made of copper, which can reduce the cost of the circuit board 10 and has good conductivity. Of course, this is not limited to this. In other embodiments, the conductive material can also be a conductive metal such as silver, a conductive non-metal, a conductive alloy, etc.; at the same time, the conductive materials forming the conductive line 21 and the dummy structure 22 can also be set to different conductive materials.

[0034] Specifically, the imprinting mold 20 includes a substrate 4, the substrate 4 has a first surface, the first surface has a conductive groove forming area for forming the conductive groove 31, and a non-conductive forming area located around the conductive groove forming area. The first imprinting structure 5 covers the conductive groove forming area, and the second imprinting structure 6 is arranged in the non-conductive forming area.

[0035] It is known that all areas of the first surface except the conductive groove forming area are the non-conductive forming area. For the embossing glue 3, all areas except the conductive area corresponding to the target conductive circuit are non-conductive areas.

[0036] It is known that when the embossing mold 20 is used to emboss the embossing adhesive 3 , the first surface faces the embossing adhesive 3 , so as to form a pattern on the embossing adhesive 3 that is complementary to the pattern on the first surface.

[0037] Furthermore, the protrusion heights of the first embossing structure 5 and the second embossing structure 6 are the same.

[0038] Furthermore, the spacing between the second imprinting structure 6 and the first imprinting structure 5 is 0.2 mm to 2 mm. This ensures that the spacing between the second imprinting structure 6 and the first imprinting structure 5 is not too small, the distance between the conductive groove 31 formed by the first imprinting structure 5 and the non-conductive groove 32 formed by the second imprinting structure 6 is not too close to cause connection, and the distance between the corresponding conductive circuit 21 and the virtual structure 22 is not too small, which can avoid electrical connection between the conductive circuit 21 and the virtual structure 22; at the same time, the spacing between the second imprinting structure 6 and the first imprinting structure 5 is not too large, and the distance between the corresponding conductive groove 31 and the non-conductive groove 32 is not too large, so that when the imprinting mold 20 is removed, the demolding stress in the area around the conductive groove 31 is more balanced, which has less impact on the size of the entire sheet and can improve the demolding yield.

[0039] In a specific embodiment, the distance between the second embossing structure 6 and the first embossing structure 5 is 0.5 mm. Of course, this is not limited to this.

[0040] Furthermore, the second embossing structures 6 are arranged at intervals around the first embossing structures 5. Correspondingly, the non-conductive grooves 32 are arranged around each conductive groove 31, so that when the embossing mold 20 is removed, the demoulding stress of the area around the conductive groove 31 is more balanced, which has little effect on the size of the whole sheet and can improve the demoulding yield; at the same time, the color difference uniformity of the whole circuit board 10 finally prepared can be better.

[0041] In the embossing mold 20 in the first embodiment of the present invention, the non-conductive forming area has a spacing area located on the peripheral side of the first embossing structure 5 and extending along the extension direction of the first embossing structure 5, and the non-conductive forming area except the spacing area is provided with the second embossing structure 6, that is, the second embossing structure 6 is arranged in a sheet shape, and the embossing mold 20 has a gap only between the first embossing structure 5 and the second embossing structure 6, which can maximize the area of ​​the groove area in the embossing glue 3, and further make the whole fabric more detachable when the embossing mold 20 is removed. The mold stress is relatively balanced, which has little effect on the size of the entire sheet, and can improve the demolding yield; at the same time, for the prepared circuit board 10, its conductive layer 2 is only composed of a conductive circuit 21 located in a conductive groove 31, a virtual structure 22 located in a non-conductive groove 32, and a polymer 23 located between the conductive circuit 21 and the virtual structure 22 to separate the conductive circuit 21 and the virtual structure 22, thereby maximizing the area of ​​the virtual structure 22, maximizing the area of ​​the conductive layer 2 occupied by the circuit area, and further making the overall color difference uniformity of the circuit board 10 better.

[0042] Combination Figure 1 as well as Figure 2 As shown, the circuit board 10 prepared by the stamping mold 20 in the first embodiment of the present invention comprises a substrate 1, a conductive layer 2 located on the substrate 1, the conductive layer 2 comprises a conductive line 21, a dummy structure 22 spaced apart from the conductive line 21, and a polymer 23 located around the dummy structure 22. In the present invention, by adding the dummy structure 22 in the conductive layer 2, on the one hand, the duty ratio of the line area and the non-line area in the conductive layer 2 can be reduced, so that the overall color difference uniformity of the circuit board 10 is better; on the other hand, when the conductive groove 31 for accommodating the conductive line 21 and the non-conductive groove 32 for accommodating the dummy structure 22 are formed on the polymer 23 (stamping glue 3) by the stamping mold 20, the duty ratio of the groove area and the non-groove area can be reduced, so that when the stamping mold 20 is removed, the demoulding stress of the entire sheet is more balanced, the size of the entire sheet is less affected, and the demoulding yield can be improved.

[0043] In a specific implementation, the circuit board 10 is a mini LED circuit board, but of course, it is not limited to this.

[0044] Furthermore, the conductive circuit 21 , the dummy structure 22 , and the polymer 23 are flush with each other on a side away from the substrate 1 , which can meet the requirement of surface flatness of the circuit board 10 .

[0045] Furthermore, the spacing between the conductive circuit 21 and the dummy structure 22 is 0.2 mm to 2 mm. This ensures that the distance between the conductive circuit 21 and the dummy structure 22 is not too small, and electrical connection between the conductive circuit 21 and the dummy structure 22 can be avoided; at the same time, the distance between the conductive circuit 21 and the dummy structure 22 is not too large, and the distance between the corresponding conductive groove 31 and the non-conductive groove 32 is not too large, so that when the imprint mold 20 is removed, the demoulding stress in the area around the conductive groove 31 is more balanced, which has less impact on the size of the entire sheet and can improve the demoulding yield.

[0046] In a specific implementation, the distance between the conductive circuit 21 and the dummy structure 22 is 0.5 mm. Of course, this is not limited thereto.

[0047] It can be known that the conductive circuit 21 and the dummy structure 22 are separated by the polymer 23, so that the electrical connection between the conductive circuit 21 and the dummy structure 22 can be avoided and the conductive layer 2 can be made more stable.

[0048] Furthermore, each of the conductive circuits 21 has the virtual structure 22 on its peripheral side, and correspondingly, each of the conductive grooves 31 has the non-conductive grooves 32 on its peripheral side, so that when the imprinting mold 20 is removed, the demolding stress in the area around the conductive grooves 31 is more balanced, which has less impact on the size of the entire sheet and can improve the demolding yield.

[0049] In this embodiment, the conductive circuit 21 divides the conductive layer 2 into a plurality of non-conductive areas, and the conductive layer 2 has a virtual structure 22 corresponding to the non-conductive area one by one, and the virtual structure 22 and the polymer 23 located between the virtual structure 22 and the corresponding conductive circuit 21 cover the corresponding non-conductive area. That is, the virtual structure 22 in this embodiment is arranged in a sheet shape, and the conductive layer 2 is only composed of the conductive circuit 21, the virtual structure 22, and the polymer 23 located between the conductive circuit 21 and the virtual structure 22 to separate the conductive circuit 21 and the virtual structure 22. The area of ​​the virtual structure 22 is maximized, so that the area of ​​the circuit area occupied by the conductive layer 2 is maximized, and the color difference uniformity of the circuit board 10 as a whole is further improved; correspondingly, the area of ​​the groove area in the polymer 23 is maximized, and when the stamping mold 20 is removed, the demoulding stress of the entire surface is further balanced, which has little effect on the size of the entire sheet material and can improve the demoulding yield.

[0050] Combination Figure 3-4 1 and 2 show a method for preparing the circuit board 20a using the imprinting mold 20a in the second embodiment of the present invention and the prepared circuit board 20a.

[0051] Please refer to Figure 3 as well as Figure 4 As shown, the difference between the imprinting mold 20a in the second embodiment and the imprinting mold 20 in the first embodiment is that: in the imprinting mold 20a, the second imprinting structure 6a is a strip-shaped structure extending along the extension direction of the first imprinting structure 5 on the peripheral side of the first imprinting structure 5. Therefore, after the imprinting mold 20a is imprinted on the imprinting glue 3, a conductive groove 31 and a long strip of non-conductive groove 32a only around the outer circumference of the conductive groove 31 are formed on the imprinting glue 3, which can reduce the subsequent filling of conductive materials, and reduce the area of ​​the non-conductive groove on the basis of making the demoulding stress of the entire surface more balanced when demoulding is achieved, thereby reducing the filling amount of conductive materials in the conductive layer 2a and reducing costs.

[0052] Specifically, the first embossing structure 5 divides the first surface into a plurality of non-conductive forming areas, and the embossing mold 20a has a second embossing structure 6a corresponding to the non-conductive forming areas one by one, and the second embossing structure 6a is an annular embossing structure corresponding to the contour line of the non-conductive forming area, that is, the embossing mold 20a includes a plurality of annular second embossing structures 6a. The first embossing structure 5 in the embossing mold 20a and the outer ring between the second embossing structure 6a and the inner ring inside the second embossing structure 6a are all in a groove shape and do not have an embossing structure. Correspondingly, the conductive layer 2a in the circuit board 10a finally formed includes a conductive circuit 21, a dummy structure 22a, and a polymer 23 located between the outer ring of the dummy structure 22a and the conductive circuit 21 and located within the inner ring of the dummy structure 22a.

[0053] Furthermore, the width of the second embossing structure 6a is 0.2 mm to 20 mm. On the basis of achieving a relatively balanced demoulding stress of the entire surface during demoulding, the area of ​​the dummy structure 22 is reduced, thereby reducing the amount of conductive material filled subsequently and reducing costs.

[0054] In a specific embodiment, the width of the second embossing structure 6a is 0.85 mm, but it is not limited thereto.

[0055] Correspondingly, the method for preparing the circuit board 10a using the imprinting mold 20a in the second embodiment of the present invention is the same as the method for preparing the circuit board 10 using the imprinting mold 20 in the first embodiment of the present invention, and will not be repeated here.

[0056] Correspondingly, combined Figure 4As shown, the conductive circuit 21 in the circuit board 10a prepared by the imprinting mold 20a in the second embodiment of the present invention divides the conductive layer 2a into a plurality of non-conductive areas, and the conductive layer 2a has a virtual structure 22a corresponding to the non-conductive area one by one, and the virtual structure 22a is in a ring shape corresponding to the contour line of the corresponding non-conductive area, and the polymer 23a is located between the outer ring of the virtual structure 22 and the corresponding conductive circuit 21 and in the inner ring of the virtual structure 22a. That is, the virtual structure 22a is in a strip shape extending along the extension direction of the conductive circuit 21 on the side of the conductive circuit 21, and the area of ​​the virtual structure 22a is reduced on the basis of making the demoulding stress of the entire surface relatively balanced when demoulding is achieved, thereby reducing the filling amount of the conductive material in the conductive layer 2a and reducing the cost.

[0057] Furthermore, the width of the dummy structure 22a is 0.2 mm to 20 mm. On the basis of achieving a more balanced demoulding stress of the entire surface during demoulding, the area of ​​the dummy structure 22a is reduced, thereby reducing the amount of conductive material filled in the conductive layer 2a and reducing costs.

[0058] In a specific implementation, the width of the dummy structure 22a is 0.85 mm, but of course, it is not limited thereto.

[0059] Compared with the prior art, in the method for preparing a circuit board of the present invention, a second embossing structure 6, 6a is added to the non-conductive forming area in the embossing mold 20, 20a, and then after the embossing mold 20, 20a embosses the embossing glue 3, a non-conductive groove 32 is also added to the non-conductive area in the embossing glue 3, which can reduce the duty ratio of the groove area and the non-groove area in the embossing glue 3. Therefore, when the embossing glue 3 is cured to form the polymer 23, 23a and the embossing mold 20, 20a is separated, that is, when demolding, the demolding stress of the entire sheet material can be more balanced, the effect on the size of the entire sheet material is small, and the demolding yield can be improved; at the same time, the non-conductive area in the circuit board 10, 10a finally prepared is also added with an inactive virtual structure, which can reduce the duty ratio of the line area and the non-line area in the conductive layer 2, so that the overall color difference uniformity of the circuit board 10, 10a is better.

[0060] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0061] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a circuit board, Features: The steps include: Applying embossing glue on the substrate; Providing an imprinting mold, wherein the imprinting mold is provided with a first imprinting structure corresponding to a target conductive circuit and a second imprinting structure corresponding to a target virtual structure, wherein the first imprinting structure and the second imprinting structure are arranged at an interval; Imprinting the embossing adhesive using an imprinting mold, separating the imprinting mold after the embossing adhesive is solidified, and forming a conductive groove corresponding to the first imprinting structure and a non-conductive groove corresponding to the second imprinting structure on the embossing adhesive; The conductive groove is filled with a conductive material to form a conductive circuit, and the non-conductive groove is filled with a conductive material to form a dummy structure.

2. The method for preparing a circuit board according to claim 1, Features: The embossing adhesive is a light-curing adhesive or a heat-curing adhesive.

3. The method for preparing a circuit board according to claim 1, Features: The conductive material is copper.

4. The method for preparing a circuit board according to claim 1, Features: The distance between the second embossing structure and the first embossing structure is 0.2 mm to 2 mm.

5. The method for preparing a circuit board according to claim 1, Features: The second embossing structures are arranged at intervals around the first embossing structure.

6. The method for preparing a circuit board according to claim 5, Features: The imprinting mold includes a substrate, the substrate has a first surface, the first surface has a conductive groove forming area for forming the conductive groove, and a non-conductive forming area located around the conductive groove forming area, the first imprinting structure covers the conductive groove forming area; the non-conductive forming area has a spacing area located on the peripheral side of the first imprinting structure and extending along the extension direction of the first imprinting structure, and the non-conductive forming areas except the spacing area are all provided with the second imprinting structure.

7. The method for preparing a circuit board according to claim 5, Features: The second imprinting structure is a strip-shaped structure extending along an extension direction of the first imprinting structure at a peripheral side of the first imprinting structure.

8. The method for preparing a circuit board according to claim 7, Features: The width of the second embossed structure is 0.2 mm to 20 mm.

9. The method for preparing a circuit board according to claim 7, Features: The second embossing structure includes a plurality of annular embossing structures.

10. The method for preparing a circuit board according to claim 1, Features: The first embossing structure and the second embossing structure have the same protrusion height.

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