Conductive circuit board with controllable transmittance and preparation method thereof

Abstract

The invention discloses a controllable transmittance conductive circuit board and a preparation method thereof, and belongs to the technical field of circuit boards, the controllable transmittance conductive circuit board comprises a base material, the base material is made of one of polyamide, transparent polyimide, polyethylene glycol terephthalate and cycloolefin polymer, and the thickness of the base material is 25-500 [mu] m; the invention discloses a copper-clad plate, which comprises a base material, an alloy plating layer, which is arranged on the base material and is made of copper alloy, and the thickness of the alloy plating layer is 1-50 [mu] m. According to the invention, polyamide, transparent polyimide, polyethylene glycol terephthalate or cycloolefin polymer is used as a substrate material of the circuit board, so that the substrate has high light transmittance while having good physical properties and stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit boards, and in particular relates to a controllable transmittance conductive circuit board and a preparation method thereof. Background Art

[0002] Circuit boards are an indispensable part of electronic equipment. They are responsible for connecting various electronic components together according to a predetermined circuit to form a complete circuit system. In order to pursue better lighting effects and visual experience, modern electronic products and instruments have increasing requirements for light transmittance.

[0003] In the existing technology, most circuit boards use polyimide (PI) film as the substrate, which has a low transmittance and cannot achieve conductivity while meeting the requirements of high transmittance. It also cannot meet the requirements of different transmittance scenarios and has a poor visual effect. Therefore, there is room for improvement. Summary of the invention

[0004] In view of the above situation, in order to overcome at least part of the defects of the above-mentioned prior art, the present invention provides a controllable transmittance conductive circuit board and a preparation method thereof.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides a controllable transmittance conductive circuit board, comprising: A substrate, wherein the material of the substrate is one of polyamide, transparent polyimide, polyethylene terephthalate and cycloolefin polymer, and the thickness of the substrate is 25 μm-500 μm; The alloy plating layer is arranged on the substrate, the material of the alloy plating layer is copper alloy, and the thickness of the alloy plating layer is 1 μm-50 μm.

[0006] In some embodiments, an anti-oxidation layer is formed on the surface of the alloy coating.

[0007] In some embodiments, further comprising: Circuits are formed on the alloy plating layer by exposure and development.

[0008] In some embodiments, during the exposure and development process, the transmittance of the circuit board is adjusted by controlling the line width of the pattern and the distance between the lines.

[0009] In some embodiments, further comprising: The optical adhesive layer is located on the back of the substrate and has a thickness of 100 μm-300 μm.

[0010] The present invention also provides a method for preparing a controllable transmittance conductive circuit board, comprising the following steps: preparing a substrate; Forming an alloy coating on the entire surface of the substrate by electroplating, and passivating the alloy coating to form an anti-oxidation layer; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is applied to the back of the substrate by roller bonding to form an optical adhesive layer.

[0011] In some embodiments, the electroplating comprises the steps of: Activate the circuit board in palladium activation solution; The circuit board is immersed in a plating solution containing copper ions and nickel ions, and a copper-nickel alloy is deposited on the surface by electrolysis; Clean and dry the circuit board.

[0012] In some embodiments, the passivation process comprises the following steps: Immersing the electroplated circuit board in a passivation solution to form a passivation film; Clean and dry the circuit board.

[0013] In some embodiments, further comprising: The optical adhesive layer is degassed by heating and pressurizing.

[0014] In some embodiments, further comprising: After the optical adhesive is applied to form an optical adhesive layer, laser cutting is used for shape processing.

[0015] The beneficial effects achieved by the present invention are as follows: By using polyamide, transparent polyimide, polyethylene terephthalate or cycloolefin polymer, the substrate has good physical properties and stability while having a high light transmittance; a copper alloy plating layer is provided on the surface of the substrate, so that the circuit board has better conductive properties while meeting the requirements of high transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a controllable transmittance conductive circuit board according to an embodiment of the present invention.

[0017] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0020] In view of the deficiencies in the prior art mentioned in the background technology, a first aspect of an embodiment of the present invention provides a controllable transmittance conductive circuit board, comprising: A substrate, wherein the material of the substrate is one of polyamide, transparent polyimide, polyethylene terephthalate and cycloolefin polymer, and the thickness of the substrate is 25 μm-500 μm; The alloy plating layer is arranged on the substrate, the material of the alloy plating layer is copper alloy, and the thickness of the alloy plating layer is 1μm-50μm.

[0021] Reference Figure 1 By using polyamide (PA), transparent polyimide (CPI), polyethylene terephthalate (PET) or cycloolefin polymer (COP) as the substrate material of the circuit board, the substrate has good physical properties and stability while having a high light transmittance; a copper alloy plating layer is provided on the surface of the substrate, which can make the circuit board have better conductive properties while meeting the demand for high transmittance.

[0022] Preferably, the material of the substrate is cycloolefin polymer (COP). According to tests, the transmittance of cycloolefin polymer is higher than that of polyamide, transparent polyimide and polyethylene terephthalate, which can reach 90%. In addition, cycloolefin polymer also has high mechanical strength and can meet the requirements of the circuit board for load-bearing capacity and stability.

[0023] Among them, the thickness of the substrate affects the mechanical strength and transmittance of the circuit board. The smaller the thickness of the substrate, the higher the transmittance and the lower the mechanical strength. Conversely, the thicker the substrate, the lower the transmittance and the higher the mechanical strength. Therefore, limiting the thickness of the substrate to 25μm-500μm can meet the mechanical strength of the circuit board while making the substrate have a higher transmittance. The thickness of the alloy coating determines the conductivity of the circuit board. The thicker the coating, the better the conductivity. However, too thick a coating will waste precious metal resources. Therefore, the thickness of the alloy coating is set at 1μm-50μm.

[0024] In some embodiments, an anti-oxidation layer is formed on the surface of the alloy coating, which can isolate the alloy from direct contact with corrosive substances such as oxygen, moisture, acid and alkali in the external environment, thereby slowing down or preventing the corrosion process of the alloy coating, which is beneficial to prolonging the service life of the alloy.

[0025] In some embodiments, the controllable transmittance conductive circuit board further comprises: Circuits are made on the alloy plating layer by exposure and development. The circuits on the circuit board mainly connect various electronic components (such as chips, capacitors, resistors, etc.). Through exposure and development, a predetermined circuit layout and routing rules can be prepared, so that various components can be connected to form a complete circuit system.

[0026] In some embodiments, during the exposure and development process, the transmittance of the circuit board is adjusted by controlling the line width of the pattern and the distance between the lines. By controlling the line width of the pattern and the distance between the lines, the transmittance of the circuit board can be adjusted to achieve the transmittance requirement of 10%-90%.

[0027] In some embodiments, the controllable transmittance conductive circuit board further comprises: The optical adhesive layer is located on the back of the substrate, and the thickness of the optical adhesive layer is 100 μm-300 μm.

[0028] By providing an optical adhesive layer on the back of the substrate, adhesion with a base plate or a specific outdoor background plate can be achieved, and the thickness of the optical adhesive layer is limited to 100μm-300μm, which can avoid the optical adhesive layer limiting the transmission of light and make the optical adhesive layer have better durability.

[0029] A second aspect of an embodiment of the present invention provides a method for preparing a controllable transmittance conductive circuit board, comprising the following steps: preparing a substrate; Forming an alloy coating on the entire surface of the substrate by electroplating, and passivating the alloy coating to form an anti-oxidation layer; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is applied to the back of the substrate by roller bonding to form an optical adhesive layer.

[0030] Among them, exposure is to project the original image containing the circuit pattern onto the circuit board coated with photosensitive material through the exposure equipment, development is to immerse the exposed circuit board in the developer to remove the photosensitive material of the unexposed part, and etching is to use chemical solution or physical method to remove the unnecessary parts of the circuit board, leaving only the circuit pattern protected by the photosensitive material.

[0031] In some embodiments, electroplating includes the following steps: Clean the circuit board and remove the oil stains on the surface of the circuit board; Activate the circuit board in palladium activation solution; The circuit board is immersed in a plating solution containing copper ions and nickel ions, and a copper-nickel alloy is deposited on the surface by electrolysis; Clean and dry the circuit board.

[0032] Among them, the electroplated copper-nickel alloy coating can further improve the stability and corrosion resistance of the coating and increase the service life of the circuit board.

[0033] In some embodiments, the passivation process includes the following steps: Immersing the electroplated circuit board in a passivation solution to form a passivation film; Clean and dry the circuit board.

[0034] Passivation treatment can form a dense passivation film on the surface of the metal coating. This film has good chemical stability, can effectively resist the erosion of most chemical media, and helps to extend the service life of the metal coating.

[0035] In some embodiments, the preparation method further comprises: The optical adhesive layer is degassed by heating and pressurizing.

[0036] Since a certain amount of air will remain in the optical adhesive during the bonding process, this air will form bubbles, which will seriously affect the light transmittance. Therefore, a degassing treatment is performed to remove the bubbles in the optical adhesive layer and improve the light transmittance of the optical adhesive layer.

[0037] In some embodiments, the preparation method further comprises: After the optical adhesive is applied to form an optical adhesive layer, laser cutting is used for shape processing.

[0038] Laser cutting has high precision and quality, avoiding errors and deformations, and improving the overall appearance and dimensional quality of the circuit board.

[0039] The present invention will be further described below by way of specific embodiments.

[0040] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0041] Example 1 A polyamide (PA) substrate is prepared, and the thickness of the substrate is 25 μm; Clean the circuit board, remove the oil stains on the surface of the circuit board, activate the circuit board in a palladium activation solution, immerse the circuit board in a plating solution containing copper ions and nickel ions, deposit a copper-nickel alloy on the surface by electrolysis, clean and dry the circuit board, and the thickness of the alloy plating layer is 1 μm; Immerse the electroplated circuit board in a passivation solution to form a passivation film, and then clean and dry the circuit board; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is pasted on the back of the substrate by roller lamination to form an optical adhesive layer, the thickness of the optical adhesive layer is 100 μm-300 μm, and the optical adhesive layer is degassed by heating and pressurizing; Laser cutting is used for shape processing to obtain a conductive circuit board with controllable transmittance.

[0042] Example 2 A transparent polyimide (CPI) substrate is prepared, and the thickness of the substrate is 150 μm; Clean the circuit board, remove the oil stains on the surface of the circuit board, activate the circuit board in a palladium activation solution, immerse the circuit board in a plating solution containing copper ions and nickel ions, deposit a copper-nickel alloy on the surface by electrolysis, clean and dry the circuit board, and the thickness of the alloy plating layer is 20 μm; Immerse the electroplated circuit board in a passivation solution to form a passivation film, and then clean and dry the circuit board; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is pasted on the back of the substrate by roller lamination to form an optical adhesive layer, the thickness of the optical adhesive layer is 100 μm-300 μm, and the optical adhesive layer is degassed by heating and pressurizing; Laser cutting is used for shape processing to obtain a conductive circuit board with controllable transmittance.

[0043] Example 3 A polyethylene terephthalate (PET) substrate is prepared, wherein the thickness of the substrate is 200 μm; Clean the circuit board, remove the oil stains on the surface of the circuit board, activate the circuit board in a palladium activation solution, immerse the circuit board in a plating solution containing copper ions and nickel ions, deposit a copper-nickel alloy on the surface by electrolysis, clean and dry the circuit board, and the thickness of the alloy plating layer is 40 μm; Immerse the electroplated circuit board in a passivation solution to form a passivation film, and then clean and dry the circuit board; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is pasted on the back of the substrate by roller lamination to form an optical adhesive layer, the thickness of the optical adhesive layer is 100 μm-300 μm, and the optical adhesive layer is degassed by heating and pressurizing; Laser cutting is used for shape processing to obtain a conductive circuit board with controllable transmittance.

[0044] Example 4 A cycloolefin polymer (COP) substrate is prepared, wherein the thickness of the substrate is 500 μm; Clean the circuit board, remove the oil stains on the surface of the circuit board, activate the circuit board in a palladium activation solution, immerse the circuit board in a plating solution containing copper ions and nickel ions, deposit a copper-nickel alloy on the surface by electrolysis, clean and dry the circuit board, and the thickness of the alloy plating layer is 50 μm; Immerse the electroplated circuit board in a passivation solution to form a passivation film, and then clean and dry the circuit board; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is pasted on the back of the substrate by roller lamination to form an optical adhesive layer, the thickness of the optical adhesive layer is 100 μm-300 μm, and the optical adhesive layer is degassed by heating and pressurizing; Laser cutting is used for shape processing to obtain a conductive circuit board with controllable transmittance.

[0045] Comparative Example 1 This comparative example is consistent with Example 1, the only difference being that the material of the substrate is PI.

[0046] Experimental Example 1 Under the same circuit conditions, transmittance tests were performed on Examples 1-4 and Comparative Example 1, and the results are shown in Table 1.

[0047] Table 1

[0048] It can be seen that the transmittance of Examples 1-4 is greatly improved compared with Comparative Example 1.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A controllable transmittance conductive circuit board, characterized in that: include: A substrate, wherein the material of the substrate is one of polyamide, transparent polyimide, polyethylene terephthalate and cycloolefin polymer, and the thickness of the substrate is 25 μm-500 μm; The alloy plating layer is arranged on the substrate, the material of the alloy plating layer is copper alloy, and the thickness of the alloy plating layer is 1 μm-50 μm.

2. The controllable transmittance conductive circuit board according to claim 1, characterized in that: An anti-oxidation layer is formed on the surface of the alloy plating layer.

3. The controllable transmittance conductive circuit board according to claim 1, characterized in that: Further including: Circuits are formed on the alloy plating layer by exposure and development.

4. The controllable transmittance conductive circuit board according to claim 3, characterized in that: During the exposure and development process, the transmittance of the circuit board is adjusted by controlling the line width of the pattern and the distance between the lines.

5. The controllable transmittance conductive circuit board according to claim 1, characterized in that: Further including: The optical adhesive layer is located on the back of the substrate and has a thickness of 100 μm-300 μm.

6. The method for preparing a controllable transmittance conductive circuit board according to any one of claims 1 to 5, characterized in that: The steps include: preparing a substrate; Forming an alloy coating on the entire surface of the substrate by electroplating, and passivating the alloy coating to form an anti-oxidation layer; A circuit pattern is formed by exposure, development and etching to form a circuit; Optical adhesive is applied to the back of the substrate by roller bonding to form an optical adhesive layer.

7. The preparation method according to claim 6, characterized in that: The electroplating comprises the following steps: Activate the circuit board in palladium activation solution; The circuit board is immersed in a plating solution containing copper ions and nickel ions, and a copper-nickel alloy is deposited on the surface by electrolysis; Clean and dry the circuit board.

8. The preparation method according to claim 6, characterized in that: The passivation process comprises the following steps: Immersing the electroplated circuit board in a passivation solution to form a passivation film; Clean and dry the circuit board.

9. The preparation method according to claim 6, characterized in that: Further including: The optical adhesive layer is degassed by heating and pressurizing.

10. The preparation method according to claim 6, characterized in that: Further including: After the optical adhesive is applied to form an optical adhesive layer, laser cutting is used for shape processing.

Images