An organic sacrificial layer coating and transparent substrate laser micro-welding method

Abstract

The application discloses an organic sacrificial layer coating and a transparent substrate laser micro-welding method. The organic sacrificial layer coating comprises 5-20 parts by mass of an organic polymer matrix, 0.1-1 part of light-absorbing filler and 79-94.9 parts of organic solvent; the light-absorbing filler has specific particle size and optical parameters, and has the functions of laser photo-thermal conversion and visual alignment recognition. When welding, the coating is used to prepare alignment marks on the welding areas of two transparent substrates; after high-precision alignment and pasting through a visual system, the sacrificial layer is heated and melted by using a first energy parameter laser, and the transparent substrate interface micro-welding is completed; and then a second energy parameter laser is used to pyrolyze and remove the residual sacrificial layer and excess solder. The application utilizes the organic sacrificial layer to realize selective heat absorption of laser, and can effectively avoid thermal damage of the transparent substrate; meanwhile, the single coating realizes multiple functions of alignment mark, welding heat source and welding limiting support, and the process is simple, the alignment precision is high, and the welding quality is stable.

Description

Technical Field

[0001] This invention relates to laser welding technology for transparent substrates, specifically to an organic sacrificial coating and a laser micro-welding method for transparent substrates. Background Technology

[0002] With the rapid development of optoelectronic displays, flexible electronics, smart wearables, and optical instruments, transparent materials such as glass, quartz, sapphire, and transparent polymers have become core substrate materials for high-end electronic devices and optical components due to their excellent optical transmittance, chemical stability, and mechanical strength. In practical applications, transparent substrates often require precision welding and alignment at the micron or even submicron level to meet the demands for miniaturization, integration, and high reliability in devices.

[0003] Currently, transparent substrate welding is mostly carried out using soldering iron welding, hot air welding, ultrasonic welding, or laser welding. Conventional welding processes have high temperatures and large heat-affected zones, which can easily cause deformation, aging, or even damage to low-thermal-sensitive transparent substrates such as PI and PET. While traditional laser welding has high precision, when welding double-layer transparent substrates, the laser can easily penetrate directly through the two substrates, making it impossible to form an effective heating area at the interface, making it difficult to achieve stable fusion and failing to meet the requirements of precision welding.

[0004] In the prior art, US Patent US2011 / 0200802A1 discloses a transparent polymer laser welding method, which directly carbonizes the substrate material at the transparent polymer interface using a short-pulse laser to form a high-contrast mark, and then completes the welding by secondary laser heating of the marked area. This method does not require the addition of an additional light-absorbing medium, but it has obvious drawbacks: first, it relies on the carbonization of the substrate, which can easily damage the local structure of the substrate and affect optical performance; second, it lacks a dedicated alignment structure and visual positioning system, making it impossible to achieve high-precision alignment; and third, it lacks temporary support, making it difficult to adapt to the precision assembly scenarios of high-end transparent substrates.

[0005] Therefore, how to overcome the shortcomings of the existing technology is the subject of this invention. Summary of the Invention

[0006] The purpose of this invention is to provide a method for laser micro-welding of an organic sacrificial coating and a transparent substrate to solve the above-mentioned technical problems.

[0007] To achieve the above objectives, the technical solution adopted in this invention is an organic sacrificial layer coating for laser micro-welding of transparent substrates, comprising the following components in parts by weight: 5-20 parts of organic polymer matrix; 0.1-1 part of light-absorbing filler; and 79-94.9 parts of organic solvent;

[0008] The organic polymer matrix is ​​at least one of acrylic resin, epoxy resin, and polyvinyl butyral.

[0009] The organic solvent is at least one of ethanol or ethyl acetate;

[0010] The light-absorbing filler has a particle size of 20nm~50nm, an optical density of 0.3~1.5 in the visible light and 915nm~1064nm near-infrared laser bands, and a light-blocking contrast of 60%~95%.

[0011] In the above scheme, by selecting a suitable light-absorbing filler, the resulting coating can absorb laser energy to achieve heat absorption welding, and can also form a high-contrast pattern to serve as a positioning mark.

[0012] In a further technical solution, the light-absorbing filler is carbon black.

[0013] In the above scheme, by using carbon black as a light-absorbing filler, a stable wide-band light absorption and high light-shielding effect can be achieved, ensuring sufficient welding heat and clear alignment marks.

[0014] In a further technical solution, the light-absorbing filler is a high-temperature decomposable organic pigment, which includes benzidine yellow, Hansa yellow, or phthalocyanine blue B.

[0015] In the above scheme, by selecting high-temperature decomposable organic pigments as light-absorbing fillers, the pigments are decomposed after welding, thus meeting the requirements of high light transmittance, while satisfying the requirements of light absorption and alignment.

[0016] According to a second aspect of this application, a method for laser micro-welding of a transparent substrate is provided, comprising the following steps:

[0017] S1. Using an organic sacrificial coating as described in any of the first aspects, a first organic sacrificial layer and a second organic sacrificial layer are formed at the soldering locations of two transparent substrates, wherein the first organic sacrificial layer and the second organic sacrificial layer are mated in the vertical direction to form an alignment mark;

[0018] S2. The alignment marks are identified by a vision system, and the relative positions of the two transparent substrates are adjusted by a moving platform to vertically align and bond the two transparent substrates.

[0019] S3. Focus the laser with the first energy parameter on the part to be welded, and use the light absorption characteristics of the organic sacrificial layer coating to make the first organic sacrificial layer and the second organic sacrificial layer absorb heat and melt, thereby realizing the interface welding of the two transparent substrates.

[0020] S4. The area to be welded is scanned with a laser using a second energy parameter, and the remaining organic sacrificial layer and solder are removed by pyrolysis.

[0021] The laser power of the second energy parameter is 1 / 3 to 1 / 2 of the laser power of the first energy parameter.

[0022] In the above scheme, a sacrificial layer is prepared by using the above coating to sequentially complete high-precision alignment, low thermal damage interface welding and non-damaging, residue removal.

[0023] In a further technical solution, the thickness of the first organic sacrificial layer and the second organic sacrificial layer is 10nm~3μm, the band gap is no greater than 3.4eV, and the band gap of the transparent substrate is greater than 3.5eV.

[0024] In the above scheme, by limiting the thickness and bandgap of the sacrificial layer, selective laser absorption can be achieved, with heat generated only in the sacrificial layer, thus avoiding thermal damage to the substrate.

[0025] In a further technical solution, S1, before preparing the organic sacrificial layer, further includes: performing a surface pretreatment on the transparent substrate; the surface pretreatment includes cleaning the surface of the transparent substrate and roughening the area to be soldered.

[0026] In the above solution, cleaning and roughening the substrate before welding can improve the interfacial adhesion between the sacrificial layer and the substrate, and prevent the coating from peeling off during the welding process.

[0027] In a further technical solution, in S1, the organic sacrificial coating is made into a first organic sacrificial layer and a second organic sacrificial layer by spin coating, spraying or vapor deposition process.

[0028] The above solutions employ various processes such as spin coating, spray coating, or vapor deposition to prepare coatings, offering flexible process selection to adapt to the processing needs of substrates of different sizes and operating conditions.

[0029] In a further technical solution, in S1, the projection shapes of the first organic sacrificial layer and the second organic sacrificial layer in the vertical direction are complementary.

[0030] In the above scheme, complementary alignment marks can be more clearly identified by the vision system, thus improving alignment accuracy.

[0031] In a further technical solution, the laser with the first energy parameter in S3 has a power of 20W~100W, a pulse time of 0.2ms~1ms, a spot diameter of 30μm~200μm, a welding speed of 0.5m / s~5m / s, and a laser wavelength of 915nm or 1064nm.

[0032] In the above scheme, by selecting the laser with the first energy parameter, the sacrificial layer can be fully melted, achieving a stable interface welding effect.

[0033] In a further technical solution, the laser with the second energy parameter in S4 has a power of 10W~25W, a spot diameter of 200μm~500μm, and a scanning speed of 0.2m / s~1m / s.

[0034] In the above scheme, by selecting a laser with a second energy parameter, the residual sacrificial layer and solder can be gently removed by pyrolysis, achieving residue-free and damage-free separation.

[0035] Compared with existing technologies, the organic sacrificial layer coating and transparent substrate laser micro-welding method provided in this application have at least the following technical advantages:

[0036] The organic sacrificial coating provided in this application, through reasonable proportioning and control of each component, and the addition of light-absorbing fillers with specified particle size and optical performance, results in a uniform and stable film formation. The cured coating can efficiently absorb laser energy in specific wavelengths and complete photothermal conversion, providing a sufficient heat source for transparent substrate interface welding. Simultaneously, the coating can form high-contrast patterns with significant differences in brightness and darkness, enabling precise recognition by visual alignment systems, thus simultaneously meeting the dual requirements of laser welding and machine vision positioning.

[0037] The transparent substrate laser micro-welding method provided in this application directly constructs alignment marks using an organic sacrificial layer, achieving multiple uses and a simplified structure. This sacrificial layer can not only work with a vision system to achieve micron-level high-precision alignment and bonding, but also absorb heat and melt under laser action to complete substrate interface bonding. Furthermore, it serves as a temporary support throughout the welding process, significantly improving the welding precision of transparent substrates. Attached Figure Description

[0038] Figure 1 This is a process flow diagram of an embodiment of the method of the present invention;

[0039] Figure 2 This is one possible alignment mark shape in an embodiment of the method of the present invention;

[0040] Figure 3 This is another possible alignment mark shape in the method embodiment of the present invention;

[0041] Figure 4 This is a visual alignment diagram of an embodiment of the method of the present invention;

[0042] Figure 5 This is a schematic diagram of the laser welding process with the first parameter in an embodiment of the method of the present invention;

[0043] Figure 6 This is a schematic diagram of the second parameter laser removal of excess organic sacrificial layer in an embodiment of the method of the present invention;

[0044] Figure 7This is a cross-sectional view of the welding process after completion in an embodiment of the method of the present invention.

[0045] In the above figures: 1-first transparent substrate; 11-first organic sacrificial layer; 2-second transparent substrate; 21-second organic sacrificial layer; 3-first energy parameter laser; 4-second energy parameter laser; 5-weld; 6-excess organic sacrificial layer; 7-vision alignment system; 8-moving platform. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0048] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0049] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0050] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the case.

[0051] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0052] This application provides an organic sacrificial layer coating for laser micro-welding of transparent substrates, comprising the following components in parts by weight: 5-20 parts of organic polymer matrix; 0.1-1 part of light-absorbing filler; and 79-94.9 parts of organic solvent;

[0053] The organic polymer matrix is ​​at least one of acrylic resin, epoxy resin, and polyvinyl butyral. This type of resin material has excellent film-forming properties, substrate adhesion, and light transmittance adaptability. It can quickly form a uniform, dense, and thin organic film substrate on the surface of a transparent substrate, stably coat and disperse light-absorbing fillers, avoid filler agglomeration and sedimentation, and also has good laser pyrolysis performance. It can be completely removed by laser heating in the future.

[0054] The organic solvent is at least one of ethanol or ethyl acetate; both of these organic solvents are environmentally friendly solvents with low boiling point, high volatility, and low viscosity, which can fully dissolve the above-mentioned organic polymer matrix and achieve uniform dispersion of light-absorbing fillers. The prepared coating system has good stability and is not prone to stratification and sedimentation.

[0055] The light-absorbing filler has a particle size of 20nm~50nm. This nanoscale particle size range allows the light-absorbing filler to be uniformly dispersed in the coating system, which can meet the film formation requirements of ultra-thin sacrificial layers.

[0056] The light-absorbing filler has an optical density of 0.3 to 1.5 in the visible light and near-infrared laser bands of 915 nm to 1064 nm. This reasonable optical density range allows the light-absorbing filler to stably absorb the laser energy in the corresponding bands, ensuring that the laser energy is fully converted into heat energy, thus providing a sufficient heat source for the fusion welding of the transparent substrate interface.

[0057] With a light-blocking contrast of 60% to 95%, the prepared sacrificial layer and the highly transparent substrate can form a significant difference in light and dark visuals. The formed alignment mark has clear boundaries and high recognizability, which can meet the precise recognition requirements of the equipment vision system.

[0058] It should be noted that the particle size, optical density, and shading contrast mentioned above refer to the parameters of the light-absorbing filler powder. The optical density and shading contrast were measured from the dry powder tablets of the light-absorbing filler; the shading contrast refers to the visible light reflection contrast between the standard tablet made of dry powder and the blank glass substrate.

[0059] Different types of light-absorbing fillers can be flexibly selected according to the actual welding conditions and product performance requirements. Among them, carbon black filler has excellent light-shielding and color-developing properties, high optical contrast, stable light absorption performance, and good dispersion. It can stably meet the requirements of high-precision visual alignment recognition and is suitable for laser micro-welding scenarios with high requirements for the clarity of alignment marks and the accuracy of light-shielding contrast.

[0060] For applications requiring high overall light transmittance and transparency of the transparent substrate after welding, high-temperature decomposable organic pigments can be used as light-absorbing fillers, such as benzidine yellow, Hansa yellow, and phthalocyanine blue B. These organic pigments possess excellent near-infrared laser absorption capabilities, meeting the heat absorption requirements of laser welding and visual alignment marking, while also exhibiting the characteristic of complete high-temperature pyrolysis. Under the high-temperature pyrolysis of the subsequent laser residue removal process, these organic pigments decompose and vaporize, leaving no colored residue or carbon residue. This reduces the negative impact of light-absorbing fillers on the light transmittance and cleanliness of the transparent substrate, maximizing the restoration of the original light transmittance of the transparent substrate and meeting the welding requirements of high-transmittance and high-cleanliness transparent devices.

[0061] Example 1: This example provides an organic sacrificial layer coating for laser micro-welding of transparent substrates. By mass, the proportions of each component are: 12 parts organic polymer matrix, 1 part carbon black, and 87 parts organic solvent.

[0062] The organic polymer matrix is ​​made of acrylic resin; the organic solvent is ethanol; and the carbon black particle size is 30 nm.

[0063] The above components are mixed evenly and stirred until the system is completely dissolved and the powder is fully dispersed to obtain an organic sacrificial layer coating. After spin coating and low-temperature curing, the coating forms a thin film with a thickness controlled between 30 nm and 3 μm and an optical bandgap of no more than 3.4 eV.

[0064] Example 2: This example provides an organic sacrificial layer coating for laser micro-welding of transparent substrates. The component proportions, by weight, are as follows:

[0065] 12 parts organic polymer matrix, 0.5 parts benzidine yellow, and 87.5 parts organic solvent.

[0066] The organic polymer matrix is ​​polyvinyl butyral; the organic solvent is ethyl acetate; and the particle size of benzidine yellow is controlled to be 40 nm after dispersion treatment.

[0067] The above components are mixed and stirred until the pigment is uniformly dispersed to obtain an organic sacrificial layer coating. After curing, the coating has a film thickness of approximately 40 nm to 3 μm and an optical bandgap of no more than 3.4 eV.

[0068] like Figure 1 As shown, this application also provides a method for laser micro-welding of transparent substrates, specifically including the following steps:

[0069] S1. Using the organic sacrificial coating described above, a first organic sacrificial layer 11 and a second organic sacrificial layer 21 are respectively prepared in the areas to be soldered on the first transparent substrate 1 and the second transparent substrate 2. The two organic sacrificial layers can cooperate with each other in the vertical direction to form alignment marks. In actual processing, spin coating, spray coating or vapor deposition processes can be used to prepare the organic sacrificial layers.

[0070] The thickness of the first organic sacrificial layer 11 and the second organic sacrificial layer 21 is controlled between 10 nm and 3 μm, which is compatible with the laser penetration depth. If the organic sacrificial layer is too thick, it will cause laser energy attenuation, blurring of the marking outline, and difficulty in laser penetration. If the organic sacrificial layer is too thin, it will not be able to play an effective temporary support role.

[0071] Preferably, the projection shapes of the first organic sacrificial layer 11 and the second organic sacrificial layer 21 in the vertical direction are complementary (i.e., when viewed in the vertical direction, the first organic sacrificial layer 11 and the second organic sacrificial layer 21 do not obstruct each other), thereby enabling the visual system to recognize more clearly and improving the accuracy of visual recognition and alignment. Figure 2 , Figure 3 Two typical complementary alignment marks are shown. In practical applications, other shapes can be selected according to requirements.

[0072] In addition, to improve the interfacial bonding between the sacrificial layer and the transparent substrate and prevent coating peeling during the welding process, the transparent substrate can be pretreated before the organic sacrificial layer is prepared. The pretreatment process includes overall substrate cleaning and surface roughening of the area to be welded.

[0073] S2. Using the visual alignment system 7 to identify the alignment marks, and then using the moving platform 8 to adjust the relative positions of the two transparent substrates, the vertical alignment and bonding of the substrates is finally completed. Figure 4 As shown. This step can be used with conventional picosecond laser processing equipment. The vision alignment system 7 can use a high-precision industrial camera, and the moving platform 8 can use a CNC moving platform commonly used in laser processing to achieve positioning operations.

[0074] S3. For example Figure 5 As shown, the laser 3 with the first energy parameter is focused on the area to be welded. By utilizing the light absorption characteristics of the organic sacrificial layer, the first organic sacrificial layer 11 and the second organic sacrificial layer 21 absorb heat and melt to form a weld 5, thereby realizing the interface welding of the two transparent substrates.

[0075] The laser parameters in this step are set according to the material characteristics of the organic sacrificial layer and the transparent substrate. In this embodiment, the first energy parameter is a laser wavelength of 915nm or 1064nm, a power of 20W~100W, a pulse duration of 0.2ms~1ms, a spot diameter of 30μm~200μm, and a welding speed of 0.5m / s~5m / s. During the welding process, the sacrificial layer absorbs laser energy, melts upon heating, and partially volatilizes. On the one hand, it transfers heat to the substrate contact surface; on the other hand, it can act as solder, achieving a stable bond between the two transparent substrates.

[0076] To ensure that laser energy is preferentially absorbed by the sacrificial layer, the optical bandgap of the organic sacrificial layer is no greater than 3.4 eV, while the optical bandgap of the transparent substrate is greater than 3.5 eV. This allows for the use of the difference in bandgap between the two to form a selective light absorption mechanism, thus preventing the substrate from being burned by the laser.

[0077] S4. For example Figure 6 As shown, the laser 4 with the second energy parameter is used to scan the area to be welded, and the residual excess organic sacrificial layer 6 and excess solder are removed by pyrolysis.

[0078] The laser parameters are set based on the characteristics of the organic sacrificial layer. In this embodiment, the second energy parameters are: laser power 10W~25W, spot diameter 200μm~500μm, and scanning speed 0.2m / s~1m / s. The second laser power is 1 / 3 to 1 / 2 of the first laser power, so as to remove residual material without damaging the welding interface or the optical properties of the transparent substrate.

[0079] The main purpose of this step is to remove the residual organic sacrificial layer and excess solder that were not completely decomposed after welding, resulting in the following structure: Figure 7 As shown.

[0080] Two specific embodiments are given below.

[0081] Example 3: In this example, two polycarbonate (PC) transparent substrates with a thickness of 1 mm and a light transmittance of more than 88% are selected as the workpieces to be welded. The band gap of the transparent substrate is greater than 3.5 eV.

[0082] The organic sacrificial coating was prepared according to the following mass proportions: 12 parts acrylic resin, 0.6 parts carbon black with a particle size of 30 nm, and 87.4 parts anhydrous ethanol. All components were thoroughly stirred, dispersed, and filtered to obtain a uniform and stable black sacrificial coating. The cured film of the prepared coating exhibited a light density of 0.3–1.5 in the visible light and 915–1064 nm wavelength bands, a light-blocking contrast ratio of 92%, and a band gap ≤3.4 eV.

[0083] The PC substrate underwent surface pretreatment: it was ultrasonically cleaned with anhydrous ethanol for 5 minutes and dried, and then the area to be welded was roughened by scanning with a low-power laser to achieve a roughness of Ra0.5μm.

[0084] A sacrificial layer was prepared on the substrate to be soldered using a spin coating process. The spin coating speed was 5000 rpm and the spin coating time was 10 s. The substrate was then baked at 80°C for 15 min to obtain a first organic sacrificial layer and a second organic sacrificial layer with a thickness of 800 nm and a contour size of 10 μm, which served as alignment markers.

[0085] By using a vision alignment system equipped with a high-precision industrial camera to identify alignment marks, and in conjunction with a CNC moving platform, the vertical alignment and bonding of two PC substrates can be completed, with an alignment accuracy of ±0.08μm and a substrate bonding gap of less than 2μm.

[0086] Welding was performed using a 1064nm fiber laser. The initial energy parameters were set as follows: laser power 50W, pulse duration 0.5ms, spot diameter 100μm, and welding speed 2m / s. The laser was focused on the alignment mark area, and the sacrificial layer efficiently absorbed the light and heated to approximately 400℃, melting and generating heat. The heat was conducted to the PC substrate interface, causing it to slightly melt and achieving stable interface welding. The sacrificial layer remained in the welding area to form the weld.

[0087] After welding, a second energy parameter laser scanning was used to remove residual material. The parameters were set as follows: power 20W, spot diameter 300μm, and scanning speed 0.5m / s. The remaining sacrificial layer was removed by pyrolysis and vaporization. The substrate temperature rise was below 40℃, and there were no residues, thermal damage, or scratches on the surface.

[0088] Tests showed that the alignment accuracy of this embodiment was ±0.08μm, the weld pull-out strength was 12MPa, the light transmittance of the substrate remained above 87% after welding, and the welding stability and appearance quality were excellent.

[0089] Example 4: In this example, a 0.5 mm thick PET transparent film and a 2 mm thick quartz glass substrate are selected as the workpieces to be welded. The band gap of both types of transparent substrates is greater than 3.5 eV.

[0090] The organic sacrificial coating was prepared according to the following proportions by weight: 10 parts epoxy resin, 0.4 parts benzidine yellow (40nm particle size), and 89.6 parts ethyl acetate. The mixture was thoroughly stirred and dispersed, then allowed to stand to defoam, resulting in a uniform and stable sacrificial coating. The cured film exhibited a light-blocking contrast of 88%.

[0091] Differentiated pretreatments were performed on the substrates: the PET film was wiped with isopropanol and then plasma cleaned for 1 minute; the quartz glass substrate was cleaned with dilute acid, rinsed with deionized water and dried to achieve a roughness of Ra0.8μm in the welding area, ensuring that the coating adhered firmly.

[0092] The sacrificial layer was prepared by spin coating at 6000 rpm for 12 s and baked at 90℃ for 20 min to obtain a circular complementary alignment mark with a thickness of 1.2 μm and a contour size of 15 μm.

[0093] High-precision industrial cameras and alignment systems are used to complete mark recognition and alignment, achieving high-precision alignment and bonding.

[0094] Welding was performed using a 915nm semiconductor laser. The first laser parameters were: power 70W, pulse time 0.6ms, spot diameter 150μm, and welding speed 1.5m / s. The sacrificial layer rapidly absorbed light and heated to 450℃, melting and generating heat, causing the PET interface to slightly melt and the quartz interface to moderately soften, forming a stable composite weld.

[0095] After welding, a second energy parameter laser was used to remove residual material. The parameters were set as follows: power 22W, spot diameter 400μm, and scanning speed 0.3m / s. After laser scanning, the coating in the non-welded areas was completely removed by pyrolysis. The temperature rise of the PET film was below 45℃, with no warping or yellowing, and the surface of the quartz substrate was clean and undamaged.

[0096] Tests showed that the alignment accuracy of this embodiment was ±0.09μm, the weld shear strength was 10MPa, the light transmittance of the quartz substrate remained above 90%, and the overall welding quality was excellent.

[0097] In summary, this application discloses an organic sacrificial layer coating and a method for laser micro-welding of transparent substrates. The organic sacrificial layer coating comprises 5-20 parts by weight of an organic polymer matrix, 0.1-1 parts by weight of a light-absorbing filler, and 79-94.9 parts by weight of an organic solvent. The light-absorbing filler has specific particle size and optical parameters, and combines laser photothermal conversion with visual alignment recognition. This invention uses this coating to prepare alignment marks on the areas to be welded on two transparent substrates. After high-precision alignment and bonding through a vision system, a laser with a first energy parameter is used to melt the sacrificial layer through heat absorption, completing the micro-welding of the transparent substrate interface. Then, a laser with a lower energy parameter is used to scan the welding area, pyrolyzing and removing residual sacrificial layer and excess solder. This invention utilizes the difference in bandgap width between the substrate and the sacrificial layer to achieve selective laser heat absorption, effectively avoiding thermal damage to the transparent substrate. Simultaneously, a single coating achieves multiple functions: alignment marking, welding heat source, and welding limiting support. The process is simple, with high alignment accuracy and stable welding quality, making it suitable for high-precision laser micro-welding scenarios on transparent substrates.

[0098] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An organic sacrificial coating for laser micro-welding of transparent substrates, characterized in that, The composition includes the following components in parts by weight: 5-20 parts organic polymer matrix; 0.1-1 part light-absorbing filler; 79-94.9 parts organic solvent; The organic polymer matrix is ​​at least one of acrylic resin, epoxy resin, and polyvinyl butyral. The organic solvent is at least one of ethanol or ethyl acetate; The light-absorbing filler has a particle size of 20nm~50nm, an optical density of 0.3~1.5 in the visible light and 915nm~1064nm near-infrared laser bands, and a light-blocking contrast of 60%~95%.

2. The organic sacrificial coating according to claim 1, characterized in that: The light-absorbing filler is carbon black.

3. The organic sacrificial coating according to claim 1, characterized in that: The light-absorbing filler is a high-temperature decomposable organic pigment, which includes benzidine yellow, Hansa yellow, or phthalocyanine blue B.

4. A method for laser micro-welding of transparent substrates, characterized in that, Includes the following steps: S1. Using the organic sacrificial coating according to any one of claims 1 to 3, a first organic sacrificial layer and a second organic sacrificial layer are formed on the welding areas of two transparent substrates, respectively, wherein the first organic sacrificial layer and the second organic sacrificial layer are mated in the vertical direction to form an alignment mark; S2. The alignment marks are identified by a vision system, and the relative positions of the two transparent substrates are adjusted by a moving platform to vertically align and bond the two transparent substrates. S3. Focus the laser with the first energy parameter on the part to be welded, and use the light absorption characteristics of the organic sacrificial layer coating to make the first organic sacrificial layer and the second organic sacrificial layer absorb heat and melt, thereby realizing the interface welding of the two transparent substrates. S4. The area to be welded is scanned with a laser using a second energy parameter, and the remaining organic sacrificial layer and solder are removed by pyrolysis. The laser power of the second energy parameter is 1 / 3 to 1 / 2 of the laser power of the first energy parameter.

5. The laser micro-welding method for transparent substrates according to claim 4, characterized in that, The thickness of the first organic sacrificial layer and the second organic sacrificial layer is 10nm~3μm, and the band gap is no greater than 3.4eV. The band gap of the transparent substrate is greater than 3.5eV.

6. The laser micro-welding method for transparent substrates according to claim 4, characterized in that, In step S1, before preparing the organic sacrificial layer, the process further includes: performing a surface pretreatment on the transparent substrate; the surface pretreatment includes cleaning the surface of the transparent substrate and roughening the area to be soldered.

7. The laser micro-welding method for transparent substrates according to claim 4, characterized in that, In S1, the organic sacrificial coating is made into a first organic sacrificial layer and a second organic sacrificial layer by spin coating, spray coating or vapor deposition process.

8. The laser micro-welding method for transparent substrates according to claim 4, characterized in that, In S1, the projection shapes of the first organic sacrificial layer and the second organic sacrificial layer in the vertical direction are complementary.

9. The laser micro-welding method for transparent substrates according to claim 4, characterized in that, The laser in S3 with the first energy parameter has a power of 20W~100W, a pulse time of 0.2ms~1ms, a spot diameter of 30μm~200μm, a welding speed of 0.5m / s~5m / s, and a laser wavelength of 915nm or 1064nm.

10. The laser micro-welding method for transparent substrates according to claim 9, characterized in that, The laser with the second energy parameter in S4 has a power of 10W~25W, a spot diameter of 200μm~500μm, and a scanning speed of 0.2m / s~1m / s.

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