阅读说明：本技术 一种通透led显示屏的线路板及制作工艺 (Circuit board of transparent LED display screen and manufacturing process ) 是由 陈子安 罗明晖 于 2021-09-28 设计创作，主要内容包括：本发明公开了一种通透LED显示屏的线路板及制作工艺,其中线路板包括PCB板和设置在PCB板一侧的LED灯珠；所述PCB板包括基板,其中基板的两个侧面均依次设置有半固化片和刻蚀后的覆铜板；PCB板的表面涂覆有绝缘散热层。区别于常规的绝缘层、散热层和防水层分别设置导致的涂层过厚以及相互层之间结合不佳导致的最终不能达到相应的效果,本发明设置的绝缘散热层为集绝缘、散热和防水为一体,具有更加轻薄的优点且无需考虑多层之间的粘合问题,在散热和防水上也具有更优异的表现,能够满足市场的需求。(The invention discloses a circuit board of a transparent LED display screen and a manufacturing process thereof, wherein the circuit board comprises a PCB and LED lamp beads arranged on one side of the PCB; the PCB comprises a substrate, wherein two side surfaces of the substrate are respectively provided with a prepreg and an etched copper-clad plate in sequence; the surface of the PCB is coated with an insulating heat dissipation layer. The insulating and heat-dissipating layer provided by the invention integrates insulation, heat dissipation and water resistance, has the advantages of being thinner and thinner, does not need to consider the problem of adhesion among multiple layers, has more excellent performance in heat dissipation and water resistance, and can meet the market demand.)

1. A circuit board for a transparent LED display screen is characterized by comprising a PCB and LED lamp beads arranged on one side of the PCB; the PCB comprises a substrate, wherein prepregs and etched copper-clad plates are sequentially arranged on two side surfaces of the substrate; the surface of the PCB is coated with an insulating heat dissipation layer.

2. The circuit board of claim 1, wherein the LED beads include one or more of white light beads, yellow light beads, blue light beads and red light beads.

3. The circuit board of claim 1, wherein the substrate is made of polyimide.

4. The circuit board of the transparent LED display screen of claim 1, wherein the thickness of the prepreg is 0.1mm, the thickness of the substrate is 0.3mm, and the thickness of the etched copper clad laminate is 0.2 mm.

5. The circuit board of the transparent LED display screen of claim 1, wherein the insulating and heat dissipating layer is made of modified polyimide, and the modified polyimide is prepared by mixing polyimide resin and a modifier in dimethylformamide and then performing vacuum drying treatment; wherein the mass ratio of the polyimide resin, the modifier and the dimethylformamide is 6-8: 2-4: 5-12.

6. The circuit board of the transparent LED display screen of claim 5, wherein the modifier is polyvinylbenzoate-coated tantalum disilicide/silica/pyridoxamine, and the preparation method of the polyvinylbenzoate-coated tantalum disilicide/silica/pyridoxamine comprises:

s1, weighing tantalum disilicide nano powder, mixing the tantalum disilicide nano powder into an ethanol water solution with the mass fraction of 50%, after ultrasonic homogenization, dropwise adding ammonia water until the pH value of the system is 7.5-8.0, performing ultrasonic homogenization again, heating the mixture to 35-45 ℃ in a reflux condensing device, dropwise adding tetraethoxysilane at the speed of 20-30 drops/min, continuously stirring a reaction solution in the dropwise adding process, and after the dropwise adding is finished, continuously stirring the reaction solution for 5-8 hours to obtain a pre-reaction solution; wherein the mass ratio of the tantalum disilicide nano powder to the ethanol aqueous solution is 1: 6-10, and the mass ratio of the ethyl orthosilicate to the ethanol aqueous solution is 1: 8-12;

s2, adding pyridoxamine hydrochloride into the pre-reaction liquid, stirring and reacting for 1-2 h, centrifuging to collect solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain tantalum disilicide/silicon dioxide/pyridoxamine particles; wherein the mass ratio of the pyriminohydrochloride to the pre-reaction liquid is 1: 8-12;

s3, weighing 4-vinylphenylboronic acid and isophorone diamine, mixing into methanol, heating to 35-45 ℃ in a reflux condensing device, and stirring for reaction for 1-2 hours to obtain a vinylphenylboronic acid ester solution; wherein the mass ratio of the 4-vinylphenylboronic acid to the isophorone diamine to the methanol is 1.24-1.56: 1.6-1.8: 10-15;

s4, adding tantalum disilicide/silicon dioxide/pyridine polyamine particles into a vinyl phenylboronate solution, adding azodiisobutyronitrile, performing reflux condensation reaction for 4-6 hours at the temperature of 60-70 ℃, centrifuging, collecting solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain the tantalum disilicide/silicon dioxide/pyridine polyamine coated with polyvinyl phenylboronate; wherein the mass ratio of the tantalum disilicide/silicon dioxide/pyridine polyamine particles to the vinyl phenylboronate solution is 1: 5-7, and the mass ratio of the azodiisobutyronitrile to the vinyl phenylboronate solution is 0.4-0.8: 100.

7. The manufacturing process of the circuit board for the through LED display screen of claim 1, comprising the steps of:

step 1, taking a copper-clad plate base material, and sequentially cutting, cleaning and drying the copper-clad plate base material to obtain a clean copper-clad plate;

step 2, exposing and developing one side surface of the cleaned copper-clad plate to obtain an inner layer circuit pattern, and then etching the inner layer circuit pattern by using etching liquid to obtain an etched copper-clad plate;

step 3, cleaning and drying both sides of the substrate, and sequentially laminating the semi-cured sheets and the etched copper-clad plate on both sides to obtain the PCB prefabricated plate;

step 4, sequentially drilling the PCB prefabricated plate to form a via hole, and carrying out metallization treatment on the via hole to obtain the PCB;

step 5, coating a layer of insulating heat dissipation layer on the surfaces of two sides of the PCB, and drying to remove the solvent to obtain the high-insulating heat dissipation PCB;

and 6, fixing the LED lamp beads on one side of the high-insulation heat-dissipation PCB, and obtaining the circuit board of the transparent LED display screen.

8. A brush as claimed in claim 7The manufacturing process of the circuit board of the LED display screen is characterized in that in the step 3, the pressing temperature is 160-200 ℃, and the pressing pressure is 120-160 kg/cm²And the pressing time is 2-3 min.

9. The manufacturing process of the circuit board for the through LED display screen of claim 7, wherein in the step 4, the aperture size of the via hole is 0.2-0.4 mm.

10. The manufacturing process of the circuit board for the through LED display screen according to claim 7, wherein in the step 5, the thickness of the insulating heat dissipation layer after drying is 20-50 μm.

Technical Field

The invention relates to the field of LED display screens, in particular to a circuit board of a transparent LED display screen and a manufacturing process thereof.

Background

The LED display screen industry is located at the downstream of an LED industry chain, is one of three terminal product lines of an LED, and along with the mature of a small-distance LED display screen technology, the application scale of the display screen keeps a relatively stable and rapid growth trend, and the display screen gradually moves from outdoor large-size display screen application to indoor, so that the LED display screen can be widely applied to the fields of outdoor advertisements, control rooms, video conferences and high-end display. The circuit board makes the circuit miniize, it is directly perceived, play an important role with electrical apparatus overall arrangement to fixed circuit's batch production and optimization, traditional LED display screen majority is LED pastes on the circuit board surface, the circuit board reassembling forms the LED display screen unit on the box structure spare, this kind of way simple process, but product ventilation heat dispersion is not good, and form to indoor outer daylighting and shelter from, and these problems of solution that penetrating LED display screen can be fine, penetrating LED display screen is through with the LED paster in the circuit board side, assemble the circuit board side again, the space between two circuit boards can form penetrating effect. However, although the conventional circuit board, such as chinese patent CN105792514B, has good permeability, the insulating film is only coated on the surface of the copper-clad plate in the manufacturing process of the circuit board, which cannot perform the functions of effective heat dissipation and water resistance, and is liable to cause damage and short circuit of the circuit board.

Disclosure of Invention

Aiming at the problems that in the prior art, the surface of a copper-clad plate is only coated with an insulating film in the manufacturing engineering of a circuit board, the copper-clad plate cannot play the roles of effective heat dissipation and water resistance, and the circuit board is easy to damage and short-circuit, the invention aims to provide the circuit board of the transparent LED display screen, which can effectively dissipate heat and prevent water, and the manufacturing process thereof.

The purpose of the invention is realized by adopting the following technical scheme:

in a first aspect, the invention provides a circuit board of a transparent LED display screen, which comprises a PCB and LED lamp beads arranged on one side of the PCB; the PCB comprises a substrate, wherein two side surfaces of the substrate are respectively provided with a prepreg and a reinforced copper-clad plate in sequence; the surface of the PCB is coated with an insulating heat dissipation layer.

Preferably, the LED lamp beads comprise one or more of white light lamp beads, yellow light lamp beads, blue light lamp beads and red light lamp beads.

Preferably, the material of the substrate is polyimide.

Preferably, the thickness of the prepreg is 0.1mm, the thickness of the substrate is 0.3mm, and the thickness of the copper clad laminate is 0.2 mm.

Preferably, the insulating and heat-dissipating layer is prepared from modified polyimide, and the modified polyimide is prepared by mixing polyimide resin and a modifier in dimethylformamide and then performing vacuum drying treatment; wherein the mass ratio of the polyimide resin, the modifier and the dimethylformamide is 6-8: 2-4: 5-12.

Preferably, the modifier is tantalum disilicide/silicon dioxide/pyrilamine coated by polyvinyl phenylboronate, and the preparation method of the tantalum disilicide/silicon dioxide/pyrilamine coated by polyvinyl phenylboronate comprises the following steps:

s1, weighing tantalum disilicide nano powder, mixing the tantalum disilicide nano powder into an ethanol water solution with the mass fraction of 50%, after ultrasonic homogenization, dropwise adding ammonia water until the pH value of the system is 7.5-8.0, performing ultrasonic homogenization again, heating the mixture to 35-45 ℃ in a reflux condensing device, dropwise adding tetraethoxysilane at the speed of 20-30 drops/min, continuously stirring a reaction solution in the dropwise adding process, and after the dropwise adding is finished, continuously stirring the reaction solution for 5-8 hours to obtain a pre-reaction solution; wherein the mass ratio of the tantalum disilicide nano powder to the ethanol aqueous solution is 1: 6-10, and the mass ratio of the ethyl orthosilicate to the ethanol aqueous solution is 1: 8-12;

s2, adding pyridoxamine hydrochloride into the pre-reaction liquid, stirring and reacting for 1-2 h, centrifuging to collect solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain tantalum disilicide/silicon dioxide/pyridoxamine particles; wherein the mass ratio of the pyriminohydrochloride to the pre-reaction liquid is 1: 8-12;

s3, weighing 4-vinylphenylboronic acid and isophorone diamine, mixing into methanol, heating to 35-45 ℃ in a reflux condensing device, and stirring for reaction for 1-2 hours to obtain a vinylphenylboronic acid ester solution; wherein the mass ratio of the 4-vinylphenylboronic acid to the isophorone diamine to the methanol is 1.24-1.56: 1.6-1.8: 10-15;

s4, adding tantalum disilicide/silicon dioxide/pyridine polyamine particles into a vinyl phenylboronate solution, adding azodiisobutyronitrile, performing reflux condensation reaction for 4-6 hours at the temperature of 60-70 ℃, centrifuging, collecting solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain the tantalum disilicide/silicon dioxide/pyridine polyamine coated with polyvinyl phenylboronate; wherein the mass ratio of the tantalum disilicide/silicon dioxide/pyridine polyamine particles to the vinyl phenylboronate solution is 1: 5-7, and the mass ratio of the azodiisobutyronitrile to the vinyl phenylboronate solution is 0.4-0.8: 100.

In a second aspect, the invention provides a manufacturing process of a circuit board of a transparent LED display screen, which comprises the following steps:

step 1, taking a copper-clad plate base material, and sequentially cutting, cleaning and drying the copper-clad plate base material to obtain a clean copper-clad plate;

step 2, exposing and developing one side surface of the cleaned copper-clad plate to obtain an inner layer circuit pattern, and then etching the inner layer circuit pattern by using etching liquid to obtain an etched copper-clad plate;

step 3, cleaning and drying both sides of the substrate, and sequentially laminating the semi-cured sheets and the etched copper-clad plate on both sides to obtain the PCB prefabricated plate;

step 4, sequentially drilling the PCB prefabricated plate to form a via hole, and carrying out metallization treatment on the via hole to obtain the PCB;

step 5, coating a layer of insulating heat dissipation layer on the surfaces of two sides of the PCB, and drying to remove the solvent to obtain the high-insulating heat dissipation PCB;

and 6, fixing the LED lamp beads on one side of the high-insulation heat-dissipation PCB, and obtaining the circuit board of the transparent LED display screen.

Preferably, in the step 3, the pressing temperature is 160-200 ℃, and the pressing pressure is 120-160 kg/cm²And the pressing time is 2-3 min.

Preferably, in the step 4, the aperture size of the via hole is 0.2-0.4 mm.

Preferably, in the step 5, the thickness of the insulating heat dissipation layer after drying is 20-50 μm.

The invention has the beneficial effects that:

the invention discloses a circuit board of a transparent LED display screen, which is provided with an insulating heat dissipation layer on the basis of the prior art, and aims to keep the surface insulativity of the circuit board and have better heat dissipation and waterproofness, so that a PCB is more durable and is not easy to damage. The insulating and heat-dissipating layer provided by the invention integrates insulation, heat dissipation and water resistance, has the advantages of being thinner and thinner, does not need to consider the problem of adhesion among multiple layers, has more excellent performance in heat dissipation and water resistance, and can meet the market demand.

The invention also discloses a manufacturing process of the circuit board of the transparent LED display screen, wherein the PCB is directly processed by using a copper-clad plate and then is pressed with a prepreg and a substrate, then an insulating heat dissipation layer is coated on the surface of the PCB, and the LED lamp beads are arranged on one side of the PCB, so that the LED display screen has the advantage of high light transmittance in application.

The insulating heat dissipation layer coated by the invention is obtained by coating a modified polyimide solution on the surface of a PCB and then drying the solution, the modified polyimide is obtained by modifying the polyimide with a modifier, the modified polyimide not only can keep better high temperature resistance, insulativity and mechanical properties, but also has greatly enhanced heat dissipation performance, improved processing performance, enhanced flexibility and stronger adhesiveness.

Drawings

The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be obtained on the basis of the following drawings without inventive effort.

FIG. 1 is a schematic diagram of a circuit board of a transparent LED display screen according to the present invention;

fig. 2 is a schematic cross-sectional view of fig. 1.

Reference numerals: the LED lamp comprises a circuit board 1, a PCB 2, LED lamp beads 3, a substrate 4, a prepreg 5, an etched copper-clad plate 6 and an insulating heat dissipation layer 7.

Detailed Description

For the purpose of more clearly illustrating the present invention and more clearly understanding the technical features, objects and advantages of the present invention, the technical solutions of the present invention will now be described in detail below, but are not to be construed as limiting the implementable scope of the present invention.

The polyimide has excellent heat resistance, high temperature resistance of more than 400 ℃, long-term use temperature range of-200 to 300 ℃, high insulativity of 10 DEG C³The dielectric constant is 4.0 under Hertz, and the dielectric loss is only 0.004-0.007. In addition, the material has strong mechanical property and stable chemical property. However, polyimide has the structural characteristics of higher molecular chain rigidity, good regularity, strong interaction force among chains and the like, is difficult to dissolve and infusible, is difficult to process and form, lacks of flexibility and brittleness, has poor adhesion with other materials, and has the defects of limitation on application of polyimide.

Silica is a stable oxide, has a high melting point, can be used in a small amount in a polymer to enhance certain properties, but is brittle, has high surface hydrophilicity and is easy to agglomerate when added in a large amount, so that the silica has poor compatibility in the polymer and weakens the stability of the polymer. Tantalum disilicide (TaSi2) is a silicide with the highest melting point, has high hardness and elastic modulus, excellent corrosion resistance and high temperature oxidation resistance, and has good compatibility, both metallic and ceramic properties, and can maintain high stability in extremely harsh environments.

The molecule of the pyridoxamine contains amino and hydroxyl, and can gradually self-polymerize under mild conditions (alkalescence).

For ease of understanding, the process of preparing the modifier of the invention is analyzed as follows:

according to the invention, tetraethoxysilane is used as a silicon source, cross-linked and coated silicon dioxide is formed on the surface of tantalum disilicide, so that a silicon dioxide/tantalum disilicide composite material is formed, then pyridoxamine is used for carrying out surface modification on the silicon dioxide/tantalum disilicide composite material, then 4-vinylphenylboronic acid is combined with vinylphenylboronic acid ester generated by isophorone diamine, then under the condition that methanol is used as a solution and azodiisobutyronitrile is used as an initiator, the vinyl group in the vinylphenylboronic acid ester is subjected to self-polymerization reaction, and the polyvinylphenylboronic acid ester generated by self-polymerization can be gradually coated on the tantalum disilicide/silicon dioxide/pyridoxamine, so that the tantalum disilicide/silicon dioxide/pyridoxamine coated by the polyvinylphenylboronic acid ester, namely the modifier, is formed. The preparation process is only the steps and principles referred to by the inventor in the preparation process, and the properties of the specifically prepared product need to be judged according to specific application conditions.

The invention is further described with reference to the following examples.

Example 1

A circuit board 1 for a transparent LED display screen is shown in figures 1-2 and comprises a PCB 2 and LED lamp beads 3 arranged on one side of the PCB 2; the PCB 2 comprises a substrate 4, wherein two side surfaces of the substrate 4 are sequentially provided with a prepreg 5 and an etched copper-clad plate 6, the substrate 4 is made of polyimide, the prepreg 5 is 0.1mm thick, the substrate 4 is 0.3mm thick, and the etched copper-clad plate 6 is 0.2mm thick; the surface of the PCB 2 is coated with an insulating heat sink layer 7.

The LED lamp beads 3 comprise one or more of white light lamp beads, yellow light lamp beads, blue light lamp beads and red light lamp beads.

The insulating heat dissipation layer 7 is prepared from modified polyimide, and the modified polyimide is prepared by mixing polyimide resin and a modifier in dimethylformamide and then performing vacuum drying treatment; wherein the mass ratio of the polyimide resin, the modifier and the dimethylformamide is 7:3: 8.

The modifier is tantalum disilicide/silicon dioxide/pyrilamine coated by polyvinyl phenylboronate, and the preparation method of the tantalum disilicide/silicon dioxide/pyrilamine coated by the polyvinyl phenylboronate comprises the following steps:

s1, weighing tantalum disilicide nano powder, mixing the tantalum disilicide nano powder into an ethanol water solution with the mass fraction of 50%, after ultrasonic homogenization, dropwise adding ammonia water until the pH value of the system is 7.5-8.0, performing ultrasonic homogenization again, heating the mixture to 35-45 ℃ in a reflux condensing device, dropwise adding tetraethoxysilane at the speed of 20-30 drops/min, continuously stirring a reaction solution in the dropwise adding process, and after the dropwise adding is finished, continuously stirring the reaction solution for 5-8 hours to obtain a pre-reaction solution; wherein the mass ratio of the tantalum disilicide nano powder to the ethanol aqueous solution is 1:8, and the mass ratio of the ethyl orthosilicate to the ethanol aqueous solution is 1: 10;

s2, adding pyridoxamine hydrochloride into the pre-reaction liquid, stirring and reacting for 1-2 h, centrifuging to collect solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain tantalum disilicide/silicon dioxide/pyridoxamine particles; wherein the mass ratio of the pyriminostrobin hydrochloride to the pre-reaction liquid is 1: 10;

s3, weighing 4-vinylphenylboronic acid and isophorone diamine, mixing into methanol, heating to 35-45 ℃ in a reflux condensing device, and stirring for reaction for 1-2 hours to obtain a vinylphenylboronic acid ester solution; wherein the mass ratio of the 4-vinylphenylboronic acid to the isophorone diamine to the methanol is 1.38:1.7: 13;

s4, adding tantalum disilicide/silicon dioxide/pyridine polyamine particles into a vinyl phenylboronate solution, adding azodiisobutyronitrile, performing reflux condensation reaction for 4-6 hours at the temperature of 60-70 ℃, centrifuging, collecting solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain the tantalum disilicide/silicon dioxide/pyridine polyamine coated with polyvinyl phenylboronate; wherein the mass ratio of the tantalum disilicide/silicon dioxide/pyridine polyamine particles to the vinyl phenylboronate solution is 1:6, and the mass ratio of the azodiisobutyronitrile to the vinyl phenylboronate solution is 0.6: 100.

The manufacturing process of the circuit board 1 of the transparent LED display screen comprises the following steps:

step 1, taking a copper-clad plate base material, and sequentially cutting, cleaning and drying the copper-clad plate base material to obtain a clean copper-clad plate;

step 2, exposing and developing one side surface of the cleaned copper-clad plate to obtain an inner layer circuit pattern, and then etching the inner layer circuit pattern by using etching liquid to obtain an etched copper-clad plate 6;

step 3, cleaning and drying both sides of the substrate 4, sequentially laminating the semi-cured sheet 5 and the etched copper-clad plate 6 on both sides, wherein the laminating temperature is 180 ℃, and the laminating pressure is 150kg/cm²Pressing for 2.5min to obtain the PCB prefabricated slab;

step 4, sequentially drilling the PCB prefabricated plate to form a via hole, wherein the aperture of the via hole is 0.3mm, and carrying out metallization treatment on the via hole to obtain a PCB 2;

step 5, coating a layer of insulating heat dissipation layer 7 on the two side surfaces of the PCB 2, and drying under reduced pressure to remove the solvent to obtain the high-insulating heat dissipation PCB 2;

and 6, fixing the LED lamp beads 3 on one side of the high-insulation heat-dissipation PCB 2 to obtain the circuit board 1 with the transparent LED display screen.

Example 2

A circuit board 1 for a transparent LED display screen is shown in figures 1-2 and comprises a PCB 2 and LED lamp beads 3 arranged on one side of the PCB 2; the PCB 2 comprises a substrate 4, wherein two side surfaces of the substrate 4 are sequentially provided with a prepreg 5 and an etched copper-clad plate 6, the substrate 4 is made of polyimide, the prepreg 5 is 0.1mm thick, the substrate 4 is 0.3mm thick, and the etched copper-clad plate 6 is 0.2mm thick; the surface of the PCB 2 is coated with an insulating heat sink layer 7.

The LED lamp beads 3 comprise one or more of white light lamp beads, yellow light lamp beads, blue light lamp beads and red light lamp beads.

The insulating heat dissipation layer 7 is prepared from modified polyimide, and the modified polyimide is prepared by mixing polyimide resin and a modifier in dimethylformamide and then performing vacuum drying treatment; wherein the mass ratio of the polyimide resin, the modifier and the dimethylformamide is 6:2: 5.

The modifier is tantalum disilicide/silicon dioxide/pyrilamine coated by polyvinyl phenylboronate, and the preparation method of the tantalum disilicide/silicon dioxide/pyrilamine coated by the polyvinyl phenylboronate comprises the following steps:

s1, weighing tantalum disilicide nano powder, mixing the tantalum disilicide nano powder into an ethanol water solution with the mass fraction of 50%, after ultrasonic homogenization, dropwise adding ammonia water until the pH value of the system is 7.5-8.0, performing ultrasonic homogenization again, heating the mixture to 35-45 ℃ in a reflux condensing device, dropwise adding tetraethoxysilane at the speed of 20-30 drops/min, continuously stirring a reaction solution in the dropwise adding process, and after the dropwise adding is finished, continuously stirring the reaction solution for 5-8 hours to obtain a pre-reaction solution; wherein the mass ratio of the tantalum disilicide nano powder to the ethanol aqueous solution is 1:6, and the mass ratio of the ethyl orthosilicate to the ethanol aqueous solution is 1: 8;

s2, adding pyridoxamine hydrochloride into the pre-reaction liquid, stirring and reacting for 1-2 h, centrifuging to collect solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain tantalum disilicide/silicon dioxide/pyridoxamine particles; wherein the mass ratio of the pyriminostrobin hydrochloride to the pre-reaction liquid is 1: 8;

s3, weighing 4-vinylphenylboronic acid and isophorone diamine, mixing into methanol, heating to 35-45 ℃ in a reflux condensing device, and stirring for reaction for 1-2 hours to obtain a vinylphenylboronic acid ester solution; wherein the mass ratio of the 4-vinylphenylboronic acid to the isophorone diamine to the methanol is 1.24:1.6: 10;

s4, adding tantalum disilicide/silicon dioxide/pyridine polyamine particles into a vinyl phenylboronate solution, adding azodiisobutyronitrile, performing reflux condensation reaction for 4-6 hours at the temperature of 60-70 ℃, centrifuging, collecting solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain the tantalum disilicide/silicon dioxide/pyridine polyamine coated with polyvinyl phenylboronate; wherein the mass ratio of the tantalum disilicide/silicon dioxide/pyridine polyamine particles to the vinyl phenylboronate solution is 1:5, and the mass ratio of the azodiisobutyronitrile to the vinyl phenylboronate solution is 0.4: 100.

The manufacturing process of the circuit board 1 of the transparent LED display screen comprises the following steps:

step 1, taking a copper-clad plate base material, and sequentially cutting, cleaning and drying the copper-clad plate base material to obtain a clean copper-clad plate;

step 2, exposing and developing one side surface of the cleaned copper-clad plate to obtain an inner layer circuit pattern, and then etching the inner layer circuit pattern by using etching liquid to obtain an etched copper-clad plate 6;

step 3, cleaning and drying both sides of the substrate 4, sequentially laminating the semi-cured sheet 5 and the etched copper-clad plate 6 on both sides, wherein the laminating temperature is 160 ℃, and the laminating pressure is 120kg/cm²Pressing for 2min to obtain the PCB prefabricated board;

step 4, sequentially drilling the PCB prefabricated plate to form a via hole, wherein the aperture of the via hole is 0.2mm, and carrying out metallization treatment on the via hole to obtain a PCB 2;

step 5, coating a layer of insulating heat dissipation layer 7 on the two side surfaces of the PCB 2, and drying under reduced pressure to remove the solvent to obtain the high-insulating heat dissipation PCB 2;

and 6, fixing the LED lamp beads 3 on one side of the high-insulation heat-dissipation PCB 2 to obtain the circuit board 1 with the transparent LED display screen.

Example 3

A circuit board 1 for a transparent LED display screen is shown in figures 1-2 and comprises a PCB 2 and LED lamp beads 3 arranged on one side of the PCB 2; the PCB 2 comprises a substrate 4, wherein two side surfaces of the substrate 4 are sequentially provided with a prepreg 5 and an etched copper-clad plate 6, the substrate 4 is made of polyimide, the prepreg 5 is 0.1mm thick, the substrate 4 is 0.3mm thick, and the etched copper-clad plate 6 is 0.2mm thick; the surface of the PCB 2 is coated with an insulating heat sink layer 7.

The LED lamp beads 3 comprise one or more of white light lamp beads, yellow light lamp beads, blue light lamp beads and red light lamp beads.

The insulating heat dissipation layer 7 is prepared from modified polyimide, and the modified polyimide is prepared by mixing polyimide resin and a modifier in dimethylformamide and then performing vacuum drying treatment; wherein the mass ratio of the polyimide resin, the modifier and the dimethylformamide is 8:4: 12.

The modifier is tantalum disilicide/silicon dioxide/pyrilamine coated by polyvinyl phenylboronate, and the preparation method of the tantalum disilicide/silicon dioxide/pyrilamine coated by the polyvinyl phenylboronate comprises the following steps:

s1, weighing tantalum disilicide nano powder, mixing the tantalum disilicide nano powder into an ethanol water solution with the mass fraction of 50%, after ultrasonic homogenization, dropwise adding ammonia water until the pH value of the system is 7.5-8.0, performing ultrasonic homogenization again, heating the mixture to 35-45 ℃ in a reflux condensing device, dropwise adding tetraethoxysilane at the speed of 20-30 drops/min, continuously stirring a reaction solution in the dropwise adding process, and after the dropwise adding is finished, continuously stirring the reaction solution for 5-8 hours to obtain a pre-reaction solution; wherein the mass ratio of the tantalum disilicide nano powder to the ethanol aqueous solution is 1:10, and the mass ratio of the ethyl orthosilicate to the ethanol aqueous solution is 1: 12;

s2, adding pyridoxamine hydrochloride into the pre-reaction liquid, stirring and reacting for 1-2 h, centrifuging to collect solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain tantalum disilicide/silicon dioxide/pyridoxamine particles; wherein the mass ratio of the pyriminostrobin hydrochloride to the pre-reaction liquid is 1: 12;

s3, weighing 4-vinylphenylboronic acid and isophorone diamine, mixing into methanol, heating to 35-45 ℃ in a reflux condensing device, and stirring for reaction for 1-2 hours to obtain a vinylphenylboronic acid ester solution; wherein the mass ratio of the 4-vinylphenylboronic acid to the isophorone diamine to the methanol is 1.56:1.8: 15;

s4, adding tantalum disilicide/silicon dioxide/pyridine polyamine particles into a vinyl phenylboronate solution, adding azodiisobutyronitrile, performing reflux condensation reaction for 4-6 hours at the temperature of 60-70 ℃, centrifuging, collecting solid precipitates, washing with distilled water and acetone in sequence, and drying under reduced pressure to obtain the tantalum disilicide/silicon dioxide/pyridine polyamine coated with polyvinyl phenylboronate; wherein the mass ratio of the tantalum disilicide/silicon dioxide/pyridine polyamine particles to the vinyl phenylboronate solution is 1:7, and the mass ratio of the azodiisobutyronitrile to the vinyl phenylboronate solution is 0.8: 100.

The manufacturing process of the circuit board 1 of the transparent LED display screen comprises the following steps:

step 1, taking a copper-clad plate base material, and sequentially cutting, cleaning and drying the copper-clad plate base material to obtain a clean copper-clad plate;

step 2, exposing and developing one side surface of the cleaned copper-clad plate to obtain an inner layer circuit pattern, and then etching the inner layer circuit pattern by using etching liquid to obtain an etched copper-clad plate 6;

step 3, cleaning and drying both sides of the substrate 4, sequentially laminating the semi-cured sheet 5 and the etched copper-clad plate 6 on both sides, wherein the laminating temperature is 200 ℃, and the laminating pressure is 160kg/cm²Pressing for 3min to obtain the PCB prefabricated slab;

step 4, sequentially drilling the PCB prefabricated plate to form a via hole, wherein the aperture of the via hole is 0.4mm, and carrying out metallization treatment on the via hole to obtain a PCB 2;

step 5, coating a layer of insulating heat dissipation layer 7 on the two side surfaces of the PCB 2, and drying under reduced pressure to remove the solvent to obtain the high-insulating heat dissipation PCB 2;

and 6, fixing the LED lamp beads 3 on one side of the high-insulation heat-dissipation PCB 2 to obtain the circuit board 1 with the transparent LED display screen.

Comparative example

The insulating heat dissipation layer is prepared from modified polyimide, wherein the modified polyimide is prepared by mixing polyimide resin and a modifier in a solution and then drying the mixture, and the preparation method comprises the following steps: dispersing polyimide resin and a modifier into dimethylacetamide, and performing ultrasonic homogenization to obtain a polyimide solution; wherein the mass ratio of the polyimide resin to the modifier to the dimethylacetamide is 7:3: 18.

The modifier is tantalum disilicide/silicon dioxide, and the preparation method of the tantalum disilicide/silicon dioxide comprises the following steps:

weighing tantalum disilicide nano powder, mixing the tantalum disilicide nano powder into 50% ethanol water solution, performing ultrasonic homogenization, dropwise adding ammonia water until the pH value of the system is 7.5-8.0, performing ultrasonic homogenization again, heating the mixture to 35-45 ℃ in a reflux condensing device, dropwise adding tetraethoxysilane at the speed of 20-30 drops/min, continuously stirring the reaction solution in the dropwise adding process, continuously stirring the reaction solution for 5-8 hours after the dropwise adding is finished, performing centrifugal cleaning with ethanol for three times, and performing reduced pressure drying to obtain tantalum disilicide/silicon dioxide/; wherein the mass ratio of the tantalum disilicide nano powder to the ethanol aqueous solution is 1:8, and the mass ratio of the ethyl orthosilicate to the ethanol aqueous solution is 1: 10.

In order to more clearly illustrate the invention, the performance of the insulating heat dissipation layers in examples 1 to 3 and the comparative example of the invention was tested, the peel strength was tested according to the IPC-TM-650 standard, and the moisture absorption was tested according to the GB/T1034-2008 standard, and the results are shown in Table 1.

TABLE 1 Properties of different insulating and heat-dissipating layers

As can be seen from the results of table 1, the insulating and heat dissipating layer prepared according to the present invention has better heat dissipation (higher thermal conductivity), better peel resistance (high peel strength), and better water resistance (low moisture absorption).

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.