CN115119410A

CN115119410A - Method for manufacturing miniLED backlight plate by interconnecting high-precision single-sided circuit

Info

Publication number: CN115119410A
Application number: CN202210706443.7A
Authority: CN
Inventors: 郭冉
Original assignee: Shenzhen Baroy New Material Technology Co ltd
Current assignee: Shenzhen Baroy New Material Technology Co ltd
Priority date: 2022-06-21
Filing date: 2022-06-21
Publication date: 2022-09-27

Abstract

The invention discloses a method for manufacturing a miniLED backlight board by interconnecting high-precision single-sided circuits, which comprises the steps of filling a nano metal material in a transfer material with a circuit pattern groove, sintering to form a conductive circuit pattern, transferring to a substrate, peeling off the transfer material to realize circuit transfer, coating conductive adhesive on the surface of a circuit pad, aligning welding pins of a vertical chip with P, N electrodes positioned at two ends of an LED chip to an upper glass-based single-sided circuit pad and a lower glass-based single-sided circuit pad, leaving packaging pads of control chips at two ends, and realizing the packaging of the miniLED backlight board by heating and curing the conductive adhesive. The method of the invention can avoid the problem that the thermal stability of the conventional resin-based PCB is difficult to meet the control requirement of expansion and shrinkage, can also avoid the defects of high drilling difficulty, high cost and immature hole metallization process of the glass substrate, and can simply realize the packaging of the miniLED backlight board.

Description

Method for manufacturing miniLED backlight plate by interconnecting high-precision single-sided circuit

Technical Field

The invention belongs to the technical field of miniLED backlight plate manufacturing, and particularly relates to a method for manufacturing a miniLED backlight plate by interconnecting a high-precision single-sided circuit.

Background

The miniLED partition dimming backlight plate generally adopts a double-sided circuit board, an LED chip is mounted on the front side of the circuit board, and a control chip is mounted on the back side of the circuit board. At present, a circuit is manufactured by adopting traditional mechanical drilling and electroplating through holes of a resin PCB substrate. Because the miniLED chip is smaller, the requirement of mass transfer on the position precision of a circuit board bonding pad is higher, the thermal stability characteristic of the conventional resin-based PCB is difficult to meet the control requirement of expansion and shrinkage in manufacturing, and a glass substrate is hoped to replace a resin-based circuit in the industry. But because the punching difficulty of the glass base is large, the cost is high, and the hole metallization process is not mature, the comprehensive industrialization is difficult to realize.

Therefore, there is still a need for a method for manufacturing a miniLED segmented backlight panel using a glass substrate.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a method for manufacturing a miniLED backlight plate by interconnecting high-precision single-sided circuits, wherein an upper glass-based single-sided circuit and a lower glass-based single-sided circuit are adopted to clamp an upper anode and a lower cathode of a vertical LED chip, so that the chip at a specific position of an LED array is driven to emit light, glass punching is not needed, and LED light rays are penetrated through transparent glass.

In order to achieve the above purpose, the invention adopts the following technical scheme:

a method for manufacturing miniLED backlight board by interconnection of high-precision single-sided circuits comprises the following steps:

1) manufacturing a high-precision pattern groove on the surface of a transfer printing template;

2) filling the nano metal ink into the pattern groove on the surface of the transfer printing template, and then sintering to form a conductive circuit;

3) coating an adhesive on the surface of one side of the glass substrate, and pressing a transfer printing template filled with the sintered conductive circuit on the surface of one side of the glass substrate with the adhesive to realize the contact of the adhesive and the conductive layer;

4) curing the adhesive, and adhering the sintered circuit in the transfer printing template on the glass substrate;

5) removing the adhesive on the surface of the glass substrate where the circuit is not covered to obtain a P electrode circuit printed on the glass substrate;

6) repeating the steps 1) to 5) to obtain an N-pole circuit printed on the glass substrate;

7) coating conductive adhesive or solder paste on the surface of the P, N-electrode circuit bonding pad, aligning the welding feet of the vertical chips of the P, N electrodes at the two ends of the LED chip to the upper glass-based single-sided circuit bonding pad and the lower glass-based single-sided circuit bonding pad, and leaving the encapsulation bonding pads of the control chip at the two ends of the glass substrate circuit;

8) and (3) heating and curing the conductive adhesive or reflow soldering tin paste to realize the packaging of the miniLED backlight board.

In a specific embodiment, the material of the transfer template in step 1) is selected from inorganic materials, organic materials or metallic materials, and the transfer template is a flat plate or a cylinder with any shape; preferably, the surface of the transfer printing template is coated with a film, and then a high-precision pattern groove is manufactured on the film; more preferably, the transfer template material or the surface coating material thereof is selected from materials with low surface tension, preferably polytetrafluoroethylene materials or polydimethylsiloxane.

In a specific embodiment, the high-precision pattern groove is manufactured by adopting any one process of nano-imprinting, laser etching, mechanical engraving and electroforming; preferably, the surface of the transfer template or the surface of the coated film thereof is coated with a release agent with low surface tension, preferably a silicone release agent.

In a specific embodiment, the nano metal ink in the step 2) is prepared by mixing a nano metal powder material and a solvent in a mass ratio of 1: 99-95: 5, wherein the nano metal is selected from at least any one of copper, silver, gold, aluminum, tin, bismuth or an alloy thereof; preferably, the nano metal ink further comprises a dispersant, and the addition amount of the dispersant is 1-10% of the total mass of the nano metal and the solvent; more preferably, the nano-metallic material is selected from nano-metallic particles or alloy particles having a sintering temperature lower than the softening or melting temperature of the transfer template material or its surface coating material.

In a specific embodiment, the sintering is selected from the group consisting of heating, laser, or composite pulse sintering; preferably, when the shrinkage of the nano metal ink is large after sintering, the conductive circuit needs to be thickened by electroplating.

In a specific embodiment, the adhesive in step 3) is a thermoplastic resin, a thermosetting resin adhesive or a light-cured resin adhesive; preferably, the thermoplastic resin and the thermosetting resin glue are selected from acrylic resin or epoxy resin, and the light-cured resin glue is selected from acrylate resin.

In a particular embodiment, the adhesive is cured by heat or light in step 4); preferably, when the adhesive coated on the surface of the glass substrate is a light-cured resin adhesive, the adhesive is cured by irradiating UV light on the side of the glass substrate without the adhesive; more preferably, the UV light is incident from one side of the glass substrate through a mask or by using the LID technique in such a manner as to completely coincide with the circuit pattern, and the photo-curing type adhesive is cured, while the other adhesives without light irradiation are not cured.

In a specific embodiment, the glass-based surface adhesive without circuit covering is removed in the step 5) by solvent or acid-base washing; preferably, the solvent is selected from any one of acetone, isopropanol and ethanol, and the alkali is selected from NaOH or Na ₂ CO ₃ Preferably the mass concentration of the alkali melt<5wt.％。

In a specific embodiment, the N electrode circuit in the step 6) corresponds to the P electrode circuit pattern in the step 5) up and down.

In a specific embodiment, in the step 7), the encapsulation pads of the control chip are left at two ends of the glass substrate circuit for welding the control circuit chip and the circuit pins.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the upper and lower anodes and cathodes of the vertical LED chip are clamped by the upper and lower glass-based single-sided circuits, the chip at the specific position of the LED array is driven to emit light, glass punching is not needed, LED light rays can penetrate through the transparent glass, and meanwhile, the strength of the glass-based backlight module can be improved by adopting the structure of two pieces of glass.

In order to meet the circuit precision requirement of miniLED level, the transfer printing material with the circuit pattern groove is filled with the nano metal material, the nano material is sintered under the light wave or heat condition to form the conductive circuit pattern with excellent conductivity, and the conductive circuit pattern is transferred to the surface of the glass substrate, so that the circuit pattern meeting the precision requirement can be simply obtained.

Drawings

FIG. 1 is a schematic view of the pattern grooves on the surface of the transfer template in step 1) of the method of the present invention.

FIG. 2 is a schematic diagram of filling the nano-metal ink into the grooves in step 2) of the method of the present invention.

FIG. 3 is a schematic diagram of the sintering process of step 2) of the method of the present invention to form a conductive circuit.

FIG. 4 is a schematic view of the combination of the transfer template and the glass substrate in step 3) of the method of the present invention.

Fig. 5 is a schematic view of the step 4) of the method for curing the adhesive.

FIG. 6 is a schematic view of the solvent stripping in step 5) of the method of the present invention.

Fig. 7 is a schematic view of the miniLED chip package in step 7) of the method of the present invention.

Wherein, 1 is a substrate, 2 transfer template materials, 3 pattern grooves, 4 nanometer metal ink, 5 pulse light waves, 6 conductive circuits after sintering shrinkage, 7 glass substrates, 701 upper glass, 702 lower glass, 8UV glue, 9 masks, 10UV light, 11 uncured parts, 12 cured parts, 13N electrode circuits, 14P electrode circuits, 15LED vertical chips, 16 tin paste, 17 rows of control chips and 18 rows of control chips.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting.

A method for manufacturing a miniLED backlight plate by interconnecting high-precision single-sided circuits comprises the following steps:

In step 1), as shown in fig. 1, a high-precision pattern groove 3 is formed on the surface of a transfer template material 2 with a substrate 1, wherein the substrate 1 is usually made of high-rigidity steel, aluminum, nickel, silicon, ceramic material, and the like, and preferably ceramic material with high elastic modulus, small thermal expansion coefficient, small surface roughness and high flatness, such as alumina. The transfer template material 2 may be an inorganic material such as any one of silicon, alumina, silicon carbide, borosilicate glass, or quartz glass, an organic material such as polyimide, polytetrafluoroethylene, polysulfone, nylon, or the like, a metallic material such as aluminum alloy, high carbon steel, electroformed nickel, or the like, or a metallic material such as a plate, a cylinder, or any other shape. Or coating a film on the surface of the transfer printing template and then manufacturing a high-precision pattern groove on the film. The high-precision pattern grooves on the surface of the transfer template can be formed by nanoimprinting, laser etching, mechanical engraving, electroforming, etc., and the engraving process for the pattern grooves can be performed by the methods well known in the art.

In one case, the surface of the transfer template or the surface of the coating film thereof is coated with a release agent having a low surface tension, such as a silicone release agent or the like. In another case, the transfer template material or the surface coating material thereof is a material having a low surface tension, such as polytetrafluoroethylene.

In step 2), as shown in fig. 2, filling a nano metal ink 4 into the pattern groove 3 on the surface of the transfer template material 2, wherein the nano metal material is mixed with a solvent to prepare the nano metal ink with good fluidity, specifically, the ratio of the nano metal particles to the solvent is in the range of 1:99 to 95: 5. In one case, a certain proportion of dispersant can be added, for example, the dispersant is ionic wetting dispersant with small molecular weight such as BYK110, BYK111, and the addition amount of the dispersant is 1-10% of the total mass of the nano metal and the solvent. Specifically, the nano metal is copper, silver, gold, aluminum, tin, bismuth or an alloy thereof, preferably copper, silver or an alloy thereof; the solvent is organic solvent with boiling point below 150 deg.C such as isopropanol, acetone, xylene, and benzyl alcohol. In one case, it is preferable to select micron-sized metal particles or alloy particles having a sintering temperature lower than the softening or melting temperature of the transfer template material or its surface coating material. The sintering temperatures for the various nanometals and the softening temperatures of the transfer template material or its surface coating material are well known to those skilled in the art or may be easily determined and selected as desired.

As shown in fig. 3, the sintering of the nano metal ink is realized by the pulse light wave 5, and the conductive circuit 6 after sintering shrinkage is obtained. The sintering can be realized by heating, laser, composite pulse light wave and other methods, and can be specifically selected according to the process requirements. The conductive circuit after the nano metal ink is sintered has no adhesive force on the surface of the pattern groove and is ensured to be difficult to fall off only by the pattern groove. In one case, when the shrinkage of the nano metal ink is large after sintering, the conductive circuit needs to be thickened by electroplating, and specifically, the thickening can be selected according to the shrinkage condition, which is also a conventional circuit thickening method in the field.

In step 3), as shown in fig. 4, UV glue 8 is coated on one side surface of the glass substrate 7, and then the transfer template filled with the sintered conductive circuit is pressed on one side surface of the glass substrate with the adhesive to realize the contact between the adhesive and the conductive layer. The UV glue 8 may also be an adhesive commonly used in the art, such as a thermoplastic resin or a thermosetting resin glue, such as an acrylic resin, an epoxy resin, and the like. In one case, the adhesive is a photocurable resin adhesive, such as an acrylate resin or the like.

In step 4), as shown in fig. 5, a mask 9 is coated on the surface of the glass substrate 7 at a position corresponding to a position where there is no circuit, and the UV paste 8 at the circuit is photocured by vertical irradiation of UV light 10 while the UV paste 8 covered by the mask 9 is not cured, thereby obtaining an uncured portion 11 and a cured portion 12. Under the condition, the adhesive coated on the surface of the glass needs to be light-cured resin, UV light is incident on the side, without the adhesive, of the glass substrate to penetrate through the mask or is incident from the side, with the circuit pattern completely superposed, of the glass substrate by adopting an LID technology, so that the light-cured adhesive is cured, other adhesives without light irradiation are not cured, the transfer printing template can be more conveniently separated from the surface of the glass substrate, and the circuit layer is reserved. In another embodiment, the sintered circuit in the transfer template can be adhered to the glass substrate by a thermosetting adhesive, and the sintered circuit can be easily detached due to the fact that the surface tension of the surface of the transfer template or the surface of the coating film thereof is low and the sintered circuit has no adhesion with the adhesive.

In step 5), as shown in fig. 6, the glass-based surface adhesive without circuit coverage is further washed away with a solvent or alkali, thereby obtaining a P-pole circuit on a glass substrate. Wherein the solvent is selected from any one of acetone, isopropanol and ethanol, and the alkali is selected from NaOH or Na ₂ CO ₃ Preferably the mass concentration of the alkali solution<5wt.％。

In the step 6), repeating the steps 1) to 5) to obtain an N-pole circuit printed on the glass substrate; the positions of the N electrodes of the circuits are required to correspond to the positions of the P electrodes of the circuits one by one, and the LED vertical chips can be clamped up and down to realize effective packaging when the LED vertical chips are packaged up and down. It is understood by those skilled in the art that the N electrode circuit printed on the glass substrate can be fabricated according to steps 1) to 5), and then the P electrode circuit printed on the glass substrate can be fabricated by repeating steps 1) to 5), and this embodiment can be regarded as an equivalent solution of the present invention and should also be within the protection scope of the present invention.

In step 7), as shown in fig. 7, solder paste 16 is coated on the surface of the circuit pad, the solder tails of the P-pole circuit 14 and the N-pole circuit 13 at two ends of the LED vertical chip 15 are aligned with the upper and lower glass (701, 702) -based single-sided circuit pads, and the package pads of the control chip are left at two ends of the glass-based circuit, namely the column control chip 17 and the row control chip 18 for welding the control circuit chip and the circuit pins. The solder paste may be replaced by a conductive paste commonly used in the art.

In the step 8), the miniLED backlight plate is packaged by reflow soldering of the solder paste. When the conductive adhesive is used in the step 7), the solder reflow paste in the middle year of the step can be replaced by the heating and curing conductive adhesive, so that the miniLED backlight board is packaged.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A method for manufacturing a miniLED backlight plate by interconnecting high-precision single-sided circuits is characterized by comprising the following steps:

2. The method as claimed in claim 1, wherein the material of the transfer template in step 1) is selected from inorganic material, organic material or metallic material, and the transfer template is a flat plate or a cylinder with any shape; preferably, the surface of the transfer printing template is coated with a film, and then a high-precision pattern groove is manufactured on the film; more preferably, the transfer template material or the surface coating material thereof is selected from materials with low surface tension, preferably polytetrafluoroethylene materials or polydimethylsiloxane.

3. The method according to claim 1 or 2, wherein the high-precision pattern groove is manufactured by any one of nano-imprinting, laser etching, mechanical engraving and electroforming; preferably, a release agent with low surface tension, preferably an organic silicon release agent, is coated on the surface of the transfer printing template or the surface of the coating film thereof.

4. The method according to claim 1, wherein the nano metal ink in the step 2) is prepared by mixing a nano metal powder material and a solvent in a mass ratio of 1: 99-95: 5, and the nano metal is selected from at least any one of copper, silver, gold, aluminum, tin, bismuth or an alloy thereof; preferably, the nano metal ink further comprises a dispersant, and the addition amount of the dispersant is 1-10% of the total mass of the nano metal and the solvent; more preferably, the nano-metallic material is selected from nano-metallic particles or alloy particles having a sintering temperature lower than the softening or melting temperature of the transfer template material or its surface coating material.

5. The method of claim 1 or 4, wherein the sintering is selected from the group consisting of heating, laser, and composite pulse sintering; preferably, when the shrinkage of the nano metal ink is large after sintering, the conductive circuit needs to be thickened by electroplating.

6. The method according to claim 1, wherein the adhesive in step 3) is a thermoplastic resin, a thermosetting resin adhesive or a light-cured resin adhesive; preferably, the thermoplastic resin and the thermosetting resin glue are selected from acrylic resin or epoxy resin, and the light-cured resin glue is selected from acrylate resin.

7. The method according to claim 1, wherein the adhesive is cured by heat or light in the step 4); preferably, when the adhesive coated on the surface of the glass substrate is a light-cured resin adhesive, the adhesive is cured by irradiating UV light on the side of the glass substrate without the adhesive; more preferably, the UV light is incident from one side of the glass substrate through a mask or by using the LID technique in such a manner as to completely coincide with the circuit pattern, and the photo-curing type adhesive is cured, while the other adhesives without light irradiation are not cured.

8. The method according to claim 1, wherein the glass-based surface adhesive without circuit covering is cleaned off in step 5) by a solvent or alkali; preferably, the solvent is selected from any one of acetone, isopropanol and ethanol, and the alkali is selected from NaOH or Na ₂ CO ₃ Preferably the mass concentration of the alkali melt<5wt.％。

9. The method according to claim 1, wherein the N-pole circuit in step 6) is positioned up and down corresponding to the P-pole circuit pattern in step 5).

10. The method as claimed in claim 1, wherein in the step 7), encapsulation pads of the control chip are left at two ends of the glass substrate circuit for welding the control circuit chip and the circuit pins.