Preparation method of glass cover plate

Abstract

The invention discloses a preparation method of a glass cover plate, and belongs to the technical field of electronics. The scheme is used for carrying out ink printing on the glass cover plate with the large boss. According to the method, the sub-ink layers are sequentially formed on the concave portion of the boss through the transfer printing technology, and the sub-ink layers are sequentially formed on the flat portion of the inner surface through the silk-screen technology. And the sub-ink layer formed by the transfer printing process and the sub-ink layer formed by the screen printing process are overlapped in a transition area of the boss and the flat part. By means of the mode that transfer printing is adopted in the deep concave part and silk-screen printing is adopted in the large-area flat part, the advantages of the two technologies are fully exerted, and the printing quality and the printing efficiency are both considered. The transfer printing ink layer and the silk-screen printing ink layer are overlapped in the transition area, stress concentration can be effectively relieved, cracking is avoided, and the continuity of the visual effect and the shading and bonding functions is ensured.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a method for preparing a glass cover plate. Background Technology

[0002] With the trend towards thinner and lighter smartphones and higher integration, the industry has seen the emergence of designs that create protruding bosses in specific areas of the glass back cover to accommodate camera modules, photosensitive holes, and even some hardware circuitry. To provide more space within these bosses, their lateral cross-sections are typically large, with some single-sided or radial widths exceeding 20mm. To achieve both aesthetic appeal and functional integration, multiple layers of ink are printed on the planar areas of the inner surface of the glass back cover and the concave surfaces of the bosses, resulting in a unified, one-dimensional color for the entire glass back cover.

[0003] However, due to the special structure of the boss, the existing process faces severe challenges: the large area of ​​the inner surface is suitable for screen printing, but the concave surface of the boss is deep and steep, making it difficult for screen printing to cover the side walls and bottom, which easily leads to ink loss or uneven thickness. If spraying is used on the concave surface of the boss, uneven color is likely to occur in different parts. If pad printing is used entirely, the efficiency is low, the cost is high, and multiple layers are prone to misalignment. Furthermore, the ink layer is prone to cracking or peeling in the connection area between the concave surface of the boss and the inner surface plane.

[0004] Therefore, there is an urgent need for a special ink printing method for glass back covers with large protrusions that can balance printing integrity, interlayer adhesion, optical performance and production efficiency. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a glass cover plate, which addresses the above-mentioned deficiencies of the prior art.

[0006] To achieve the above objectives, the present invention provides a method for preparing a glass cover plate, the glass cover plate comprising a glass substrate and a composite ink layer, the glass substrate having opposing inner and outer surfaces, and a local area thereof forming an integral protrusion structure protruding outward from the main body of the glass substrate by the inner and outer surfaces being simultaneously recessed inward. The inner surface has a flat portion and a recessed portion formed by the boss structure. The recessed portion includes a flat bottom and an annular sidewall portion. A first end of the sidewall portion is connected to the flat bottom, and a second end is connected to the flat portion to form an annular transition area. The maximum width of the annular transition area in the horizontal plane is greater than 20 mm. The composite ink layer includes a plurality of sub-ink layers formed sequentially on the inner surface; The method includes the following steps: Each sub-ink layer is sequentially formed in the recessed area using a pad printing process; Each sub-ink layer is sequentially formed on the flat portion using a screen printing process. The sub-ink layer formed by the pad printing process and the sub-ink layer formed by the screen printing process form an overlapping area near the second end of the sidewall portion.

[0007] In the glass cover preparation method of the present invention, the composite ink layer includes, in order of distance from near to far from the inner surface: a main color layer, a masking layer, a light-shielding layer, and an adhesive layer; the main color layer is used to provide color effect, the masking layer is used to provide a high-reflectivity background for the main color layer, the light-shielding layer is used to prevent stray light interference, and the adhesive layer is used to enhance the bonding strength with the metal frame.

[0008] In the glass cover preparation method of the present invention, the main color layer includes a first color layer and a second color layer, the first color layer covers the inner surface, and the second color layer covers the side of the first color layer away from the inner surface.

[0009] In the glass cover preparation method of the present invention, an annular ink layer is further provided between the first color layer and the second color layer on the flat portion, and the annular ink layer is provided along the edge of the first color layer.

[0010] In the glass cover preparation method of the present invention, the light-shielding layer includes a first light-shielding layer and a second light-shielding layer, the first light-shielding layer covers the shielding layer, and the second light-shielding layer covers the side of the first light-shielding layer away from the shielding layer.

[0011] In the glass cover preparation method of the present invention, the flat bottom is provided with at least one through hole, and the glass cover preparation method further includes: transferring the main color layer on the sidewall of the through hole.

[0012] In the glass cover preparation method of the present invention, the execution order of the pad printing and screen printing processes is as follows: Each sub-ink layer is screen-printed sequentially on the flat surface. After each layer is screen-printed, a pre-curing process is performed before screen-printing the next layer. At least one outermost sub-ink layer is reserved to be applied after the transfer printing is completed. Each sub-ink layer is sequentially transferred into the recessed area. After each layer is transferred, a pre-curing treatment is performed before transferring the next layer. The glass cover is cleaned using a plasma cleaner to remove dirt adsorbed on the inner surface. The reserved sub-ink layer is screen-printed on the flat area, then pre-cured, and then the next layer is screen-printed until all screen-printing processes are completed, and then the final curing process is performed.

[0013] In the glass cover preparation method of the present invention, the execution order of the pad printing and screen printing processes is as follows: The first sub-ink layer is screen-printed on the flat portion and then pre-cured. The remaining sub-ink layer pad printing and screen printing processes are cross-combined and arranged: the pad printing process of one sub-ink layer and the screen printing process of one sub-ink layer are combined as one process combination. After the process combination is completed, a pre-curing treatment is performed. Then the next process combination is executed, and a pre-curing treatment is performed after the next process combination is completed, and so on. A process combination or an independent process is reserved at the end. Redundant screen printing or pad printing processes are grouped separately and pre-cured separately. Perform the reserved process combination or independent process, and then carry out the final curing treatment.

[0014] In the glass cover preparation method of the present invention, for the process combination, the pre-curing time is not less than the maximum value of the pre-curing time required by each process in the combination.

[0015] The present invention has the following beneficial effects: The glass cover preparation method of the present invention is used for ink printing on glass cover plates with large protrusions. The method involves sequentially forming sub-ink layers using pad printing on the recessed areas of the protrusions and sequentially forming sub-ink layers using screen printing on the flat areas of the inner surface. The sub-ink layers formed by pad printing and screen printing overlap in the transition area between the protrusions and the flat areas. By using pad printing on the deep recessed areas and screen printing on the large flat areas, the advantages of both processes are fully utilized, balancing printing quality and efficiency. The overlap between the pad-printed and screen-printed ink layers in the transition area effectively alleviates stress concentration, prevents cracking, and ensures the continuity of visual effect, light-blocking, and adhesion functions. Attached Figure Description

[0016] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0017] Figure 1 This is a side cross-sectional view of the glass cover plate provided in an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the film layer structure on the inner surface of a glass cover plate provided in some embodiments of the present invention.

[0019] Figure 3 This is a schematic diagram illustrating the steps of a glass cover plate preparation method provided in some embodiments of the present invention.

[0020] Figure 4 This is a schematic diagram of the membrane structure of the flat portion provided in some embodiments of the present invention.

[0021] Figure 5This is a schematic diagram of the membrane structure of the recessed portion provided in some embodiments of the present invention.

[0022] Figure 6 This is a schematic diagram of a flat-bottom structure provided for some embodiments of the present invention.

[0023] Figure 7 This is a schematic diagram of the process execution sequence provided in Embodiment 1 of the present invention.

[0024] Figure 8 This is a schematic diagram of the process execution sequence provided in Embodiment 2 of the present invention.

[0025] Figure 9 In accordance with Figure 7 The diagram shows a magnified view of the overlapping area of ​​the composite ink layer obtained by the process sequence shown.

[0026] Figure 10 In accordance with Figure 8 The diagram shows a magnified view of the overlapping area of ​​the composite ink layer obtained by the process sequence shown.

[0027] In the attached diagram: 100. Glass substrate; 110. Inner surface; 111. Flat portion; 112. Flat bottom; 113. Side wall portion; 114. Through hole; 120. Outer surface; 130. Boss structure; 200. Composite ink layer; 210. Main color layer; 211. First color layer; 212. Second color layer; 220. Masking layer; 230. Light-shielding layer; 231. First light-shielding layer; 232. Second light-shielding layer; 240. Adhesive layer; 250. Annular ink layer. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. It should be understood that the embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0030] This invention provides a method for preparing a glass cover plate, used for ink printing on a glass cover plate with large protrusions. For example... Figures 1-4As shown, the glass cover plate includes a glass substrate 100 and a composite ink layer 200. The glass substrate 100 has an inner surface 110 and an outer surface 120, and a local area of ​​it is formed by the inner surface 110 and the outer surface 120 being recessed inward simultaneously to form a boss structure 130 that protrudes outward from the main body of the glass substrate 100. The inner surface 110 has a flat portion 111 and a recessed portion formed by the boss structure 130. The recessed portion includes a flat bottom 112 and an annular sidewall portion 113. A first end of the sidewall portion 113 is connected to the flat bottom 112, and a second end is connected to the flat portion 111 to form an annular transition region. The maximum width of the annular transition region in the horizontal plane is greater than 20 mm.

[0031] In this embodiment of the invention, the glass cover is the back cover of a mobile phone terminal. The glass cover includes a glass substrate 100, and the inner and outer surfaces of the glass substrate 100 are simultaneously recessed inward to form a boss structure 130 that protrudes outward from the main body of the glass substrate 100. The inner surface 110 has a flat portion 111 and a recessed portion formed by the boss structure. The recessed portion includes a flat bottom 112 and an annular sidewall portion 113. The first end of the sidewall portion 113 is connected to the flat bottom 112, and the second end is connected to the flat portion 111 to form an annular transition area. The outline shape of the annular transition area is set according to actual needs, for example, it can be set as a circle or a racetrack shape. In some products, in order to accommodate the camera module, photosensitive hole, and some hardware circuits, the cross-section of the boss structure 130 is made relatively large, and the maximum width of the annular transition area in the horizontal plane usually exceeds 20mm. For the annular transition area with a racetrack-shaped profile, the maximum width of the annular transition area in the horizontal plane refers to the length of the long side of the racetrack. For the annular transition area with a circular profile, the maximum width of the annular transition area in the horizontal plane is the inner diameter of the ring. The boss structure 130 is typically located at the upper part of the back cover of the mobile phone, away from the handheld part. This allows for more space to be allocated to a larger capacity battery, enhancing the battery life of the mobile phone, while also enabling the body to be made thinner.

[0032] The composite ink layer 200 includes a plurality of sub-ink layers sequentially formed on the inner surface 110. In some embodiments of the present invention, the layers are arranged in order of distance from the inner surface 110 from near to far: a main color layer 210, a masking layer 220, a light-shielding layer 230, and an adhesive layer 240; the main color layer 210 is used to provide color effects, the masking layer 220 is used to provide a highly reflective background for the main color layer 210, the light-shielding layer 230 is used to prevent stray light interference, and the adhesive layer 240 is used to enhance the bonding strength with the metal frame.

[0033] To achieve a seamless integration of aesthetics and functionality, a composite ink layer 200 needs to be printed on the flat area 110 of the inner surface of the glass back cover and the concave surface of the protrusions, so that the glass back cover presents a unified, integrated color. For example... Figure 2 The diagram shows the structure of the glass substrate 100 and the composite ink layer 200. The main color layer 210 provides the color effect. Because the glass cover itself is transparent, after the ink is printed on its inner surface, the main color layer 210 is the first thing seen from the outer surface (the user's side). The shielding layer 220, also known as the cover layer in the industry, typically uses white ink to provide a highly reflective background for the main color layer 210. The light-shielding layer 230 typically uses dark ink to prevent stray light interference. The adhesive layer 240 uses a varnish, which is viscous and enhances the adhesion strength to the metal frame. However, there is currently no ink printing solution specifically designed for this type of large-protrusion glass cover structure.

[0034] Therefore, such as Figure 3 As shown, this invention proposes a method for preparing a glass cover plate, specifically for printing ink on the inner surface of the glass cover plate, the method comprising the following steps: Each sub-ink layer is sequentially formed in the recessed area using a pad printing process; Each sub-ink layer is sequentially formed in the flat portion 111 using a screen printing process. The sub-ink layer formed by the pad printing process and the sub-ink layer formed by the screen printing process form an overlapping area near the second end of the sidewall portion 113 to ensure interlayer continuity and sealing.

[0035] It should be noted that, regardless of whether it is the flat portion 111 or the recessed portion, the order of the above-mentioned sub-ink layers is as follows: Figure 2 The film layers shown are printed sequentially, but this invention does not limit the specific order of pad printing and screen printing processes.

[0036] In this embodiment of the invention, by employing pad printing for deep recesses and screen printing for large flat areas, the structural characteristics of both recesses and flat areas are taken into account, fully leveraging the advantages of both processes: pad printing can precisely cover steep sidewalls and bottoms, ensuring ink uniformity and integrity; screen printing, on the other hand, efficiently and cost-effectively completes large-area coating. The ink layers from pad printing and screen printing overlap in the transition zone, effectively alleviating stress concentration, preventing cracking, and ensuring continuity of visual effects, light-blocking, and adhesion. This method solves the technical challenge of existing single printing processes being unable to simultaneously achieve full coverage and high efficiency for complex 3D structures.

[0037] Figure 4 This is a schematic diagram of the membrane structure of the flat portion provided in some embodiments of the present invention. Figure 5This is a schematic diagram of the membrane structure of the recessed portion provided in some embodiments of the present invention. For example... Figure 4 , Figure 5 As shown, in some embodiments of the present invention, the main color layer 210 includes a first color layer 211 and a second color layer 212. The first color layer 211 covers the inner surface 110, and the second color layer 212 covers the side of the first color layer 211 away from the inner surface 110. The main color layer 210 is the color seen from the outer surface 120 of the glass cover. Mobile phone terminal products of the same model typically have several different color versions. By setting the first color layer 211 and the second color layer 212, the durability of the color can be enhanced, and a richer color gradation can be achieved. The first color layer 211 and the second color layer 212 can be the same color or different colors; the present invention does not impose any special limitations on this.

[0038] like Figure 4 As shown, in some embodiments of the present invention, an annular ink layer 250 is further provided between the first color layer 211 and the second color layer 212 on the flat portion 111, and the annular ink layer 250 is disposed along the edge of the first color layer 211. Adding an annular ink layer 250 to the edge of the color layer on the flat portion 111 can enhance the light-shielding and sealing performance of the edge area.

[0039] like Figure 4 , Figure 5 As shown, in some embodiments of the present invention, the light-shielding layer 230 includes a first light-shielding layer 231 and a second light-shielding layer 232. The first light-shielding layer 231 covers the shielding layer 220, and the second light-shielding layer 232 covers the side of the first light-shielding layer 231 away from the shielding layer 220. This double-layer light-shielding structure significantly improves the ability to block stray light, making it particularly suitable for high-sensitivity camera modules, preventing internal light crosstalk from degrading image quality.

[0040] like Figure 6 The diagram shows a flat-bottom structure provided in some embodiments of the present invention. Figure 6 As shown, in some embodiments of the present invention, the flat bottom 112 is provided with at least one through hole 114, and the method for preparing the glass cover plate further includes: transferring the main color layer 210 onto the sidewall of the through hole 114.

[0041] The through-holes 114 on the flat bottom 112 are typically used for camera modules and photosensitive holes. The number, location, and size of the through-holes 114 may vary in different mobile phone terminal products. To ensure the overall visual consistency of the glass cover, the main color layer 210 also needs to be printed on the sidewalls of the through-holes 114.

[0042] Example 1 In this embodiment, the execution order of each process in pad printing and screen printing is as follows: Each sub-ink layer is screen-printed sequentially on the flat surface. After each layer is screen-printed, a pre-curing process is performed before screen-printing the next layer. At least one outermost sub-ink layer is reserved to be applied after the transfer printing is completed. Each sub-ink layer is sequentially transferred into the recessed area. After each layer is transferred, a pre-curing treatment is performed before transferring the next layer. The glass cover is cleaned using a plasma cleaner to remove dirt adsorbed on the inner surface. The reserved sub-ink layer is screen-printed on the flat area, then pre-cured, and then the next layer is screen-printed until all screen-printing processes are completed, and then the final curing process is performed.

[0043] The goal of pre-curing is to bring the ink to a gel or partially cured state, causing it to lose its fluidity and fix its edges. This is typically done using low-temperature baking. The goal of final curing is to fully and completely cure the ink, typically using high-temperature baking. The duration of pre-curing and final curing depends on the type and thickness of the ink.

[0044] In this embodiment, the screen printing area and the pad printing area are pre-cured layer by layer, which is beneficial to the stable adhesion and spread of the next layer of ink. It can prevent uncured ink from being contaminated or scratched in subsequent processes. At least one outermost layer of screen printing is reserved for processing after the pad printing is completed, which ensures the surface smoothness and final adhesion.

[0045] In a specific application of this embodiment, the membrane structure of the flat portion is as follows: Figure 4 As shown, the membrane structure of the recessed portion is as follows: Figure 5 As shown. The process execution sequence is as follows: screen printing the first color layer -- pre-curing -- screen printing the ring-shaped ink layer -- pre-curing -- screen printing the second color layer -- pre-curing -- screen printing the masking layer -- pre-curing -- screen printing the first light-blocking layer -- pre-curing -- pad printing the first color layer -- pre-curing -- pad printing the first through-hole sidewall -- pre-curing -- pad printing the second color layer -- pre-curing -- pad printing the second through-hole sidewall -- pre-curing -- pad printing the masking layer -- pre-curing -- pad printing the first light-blocking layer -- pre-curing -- pad printing the second light-blocking layer -- pre-curing -- pad printing the adhesive layer -- pre-curing -- plasma cleaning -- screen printing the second light-blocking layer -- pre-curing -- screen printing the adhesive layer -- final curing. After all pad printing processes are completed and pre-cured, a total of thirteen pre-curing processes are performed. The flat part spends too much time in the pre-curing oven, resulting in its surface cleanliness not meeting the standards. Therefore, after the thirteenth pre-curing, plasma cleaning is performed first. Figure 7The diagram shows the execution sequence of each process. The actual meaning of each process symbol, the duration of each process, and the equipment length are shown in Table 1. As can be seen from Table 1, there are a total of 31 processes, with a total processing time of 117.7 minutes. Since the processes need to be performed sequentially in actual production, each process uses independent equipment to prevent confusion, and all equipment is usually arranged in a straight line. Therefore, the line length required to complete the entire ink printing task is equal to the total length of the equipment in each process, which is 171.34 meters.

[0046] Table 1. Summary of the actual meaning of each process symbol, the duration of each process, and the equipment length in Example 1.

[0047] Understandably, in practical applications, Figure 7 The sequence of processes shown can be adjusted. For example, the screen printing process for the adhesive layer can be reserved only after all the pad printing processes, or more screen printing processes can be reserved after the pad printing processes, or the position of the through-hole pad printing process can be adjusted, etc. Because all processes are performed sequentially, each printing process is pre-cured separately, such adjustments will not affect the number of processes, the total time, or the length of the production line.

[0048] This embodiment solves the problem of multi-layer ink printing on glass covers with large-area protrusions described in this invention, achieving a basically consistent overall visual effect. However, the ink printing process in this embodiment consists of 31 steps, resulting in a large number of steps, long overall time consumption, low efficiency, excessively long production lines, large factory space requirements, and high production costs. Secondly, because each layer of ink undergoes pre-curing treatment before the next layer is printed, the thickness of the ink in the overlapping area is equivalent to a simple superposition of the layer thicknesses. Therefore, in the overlapping area of ​​screen printing and pad printing near the second end of the sidewall, the ink layer thickness is relatively large. Theoretical calculations show that the maximum thickness of the overlapping area is 88.5 μm, and there are visible discoloration lines in the overlapping area. Abnormal thickness values ​​can lead to substandard inspections and even affect internal assembly, while discoloration lines directly affect the visual effect. In addition, excessively long intervals between screen printing steps may lead to the risk of delamination between adjacent sub-ink layers.

[0049] Example 2 Although Example 1 solves the problem of multi-layer ink printing on glass cover plates with large-area protrusions as described in this invention, it also has problems such as excessive ink thickness in overlapping areas, color-changing lines, low efficiency, and excessively long lines.

[0050] Therefore, this embodiment is an optimization based on Embodiment 1.

[0051] In this embodiment, the execution order of each process in pad printing and screen printing is as follows: The first sub-ink layer is screen-printed on the flat portion and then pre-cured. The remaining sub-ink layer pad printing and screen printing processes are cross-combined and arranged: the pad printing process of one sub-ink layer and the screen printing process of one sub-ink layer are combined as one process combination. After the process combination is completed, a pre-curing treatment is performed. Then the next process combination is executed, and a pre-curing treatment is performed after the next process combination is completed, and so on. A process combination or an independent process is reserved at the end. Redundant screen printing or pad printing processes are grouped separately and pre-cured separately. Perform the reserved process combination or independent process, and then carry out the final curing treatment.

[0052] In this embodiment, for process combinations, the pre-curing time is not less than the maximum pre-curing time required by each process in the combination. For example, if the pre-curing time required for the screen printing process in the combination is 84 minutes and the pre-curing time required for the pad printing process is 48 minutes, then the pre-curing time required for the combination can be set to 84 minutes, or a value slightly larger than 84 minutes, to ensure that the inks printed in the process combination, including overlapping areas, are effectively pre-cured.

[0053] In this embodiment, pad printing and screen printing processes are cross-grouped and pre-cured according to the combination, which significantly reduces the number of pre-curing processes and equipment, greatly shortens the production line cycle time, and significantly reduces production energy consumption. Within the same combination, the overlapping area is first printed with a first sub-ink layer, and then a second sub-ink layer is printed on top of it without pre-curing. Since the second sub-ink layer acts on an uncured, viscoelastic base layer, the two inks do not simply stack at the interface, but undergo molecular-level mutual penetration and fusion. Because neither is cured, the ink components diffuse into each other at the contact interface, forming a transition layer with gradually changing components, rather than two distinct layers. This fusion causes the clear physical interface to disappear, resulting in an overall thickness less than the theoretical absolute superposition value. Experiments showed that after pre-curing a 7.268µm ink layer screen-printed on the flat area, and then pre-curing a 14.966µm ink layer pad-printed on the recessed area, the ink layer thickness in the overlapping area was 22.242µm. In the flat areas, a 7.050µm ink layer is screen-printed without pre-curing. Then, a 13.947µm ink layer is transferred to the recessed areas, followed by pre-curing. The resulting ink layer thickness in the overlapping area is 17.103µm. This demonstrates that by combining the transfer printing and screen printing processes and then pre-curing them together, the ink layer thickness in the overlapping area is significantly reduced. Therefore, this embodiment significantly improves the problem of excessive thickness in the overlapping area in Embodiment 1, and the discoloration line problem is also significantly improved due to interfacial solubility.

[0054] In one specific application of this embodiment, for Figure 7 The process shown has been adjusted to obtain... Figure 8 The diagram shows the process sequence. The actual meaning of each process symbol, the duration of each process, and the equipment length are shown in Table 2 below. Figure 8 The process sequence is as follows: screen printing the first color layer -- pre-curing -- pad printing the first color layer -- screen printing the ring-shaped ink layer -- pre-curing -- pad printing the first through-hole sidewall -- screen printing the second color layer -- pre-curing -- pad printing the second color layer -- screen printing the masking layer -- pre-curing -- pad printing the second through-hole sidewall -- pre-curing -- pad printing the masking layer -- screen printing the first light-blocking layer -- pre-curing -- pad printing the first light-blocking layer -- pre-curing -- pad printing the second light-blocking layer -- screen printing the second light-blocking layer -- pre-curing -- pad printing the adhesive layer -- screen printing the adhesive layer -- final curing. There are multiple combinations of pad printing and screen printing. To achieve a smooth surface on a large area of ​​the flat section, the last process before final curing is screen printing. Because there are more pad printing processes, some pad printing processes are combined separately and pre-cured immediately after pad printing. Compared to Example 1, Example 2 reduces pre-curing time by 6 times, and pad printing and screen printing are performed alternately. The cleanliness of the inner surface of the glass cover meets product requirements, thus eliminating the need for a plasma cleaner and significantly reducing the risk of delamination between adjacent screen-printed ink layers. As shown in Table 2, there are a total of 24 processes, with a total process time of 79.7 minutes and a production line length of 132.94 meters. Compared to Example 1, this reduces 7 processes and 7 pieces of equipment, increasing production efficiency by 32.3%, saving 22.4% of space, and significantly reducing production energy consumption.

[0055] Table 2 Summary of the actual meaning of each process symbol, the duration of each process, and the equipment length in Example 2

[0056] Understandably, in practical applications, it is also possible to... Figure 8 The process shown should be adjusted. In principle, while ensuring that each sub-ink layer is printed in sequence, group pad printing and screen printing processes with similar curing times together, and group pad printing processes with shorter required pre-curing times separately. Multiple through-hole pad printing processes can also be grouped together. Within the same group, screen printing can be performed first, followed by pad printing.

[0057] like Figure 9 As shown, according to Figure 7 The diagram shows a magnified view of the overlapping area of ​​the composite ink layer obtained by the process sequence shown. Figure 10 As shown, according to Figure 8The diagram shows a magnified view of the overlapping area of ​​the composite ink layer obtained by the process sequence shown. Figure 9 and Figure 10 In the diagram, the point marked [7] is the same location in the overlapping area. Figure 9 In the middle, the ink thickness at position [7] is 69.673 μm. Figure 10 In the middle, the ink thickness at position [7] is 51.394 μm, relative to Figure 9 The thickness was reduced by 26.2%.

[0058] In Examples 1 and 2, the printing parameters used in the same process are basically the same. In the pad printing process, a silicone pad printing head is used, and the main parameters are as follows: hot air surface drying time: 1-3s, pad printing head pressing speed: 1-10mm / s, steel plate depth: 14-22um.

[0059] The above are merely specific embodiments of the present invention and should not be construed as limiting the scope of the present invention. Equivalent variations made by those skilled in the art based on this invention, as well as changes well-known to those skilled in the art, should still fall within the scope of the present invention.

Claims

1. A method for preparing a glass cover plate, characterized in that, The glass cover plate includes a glass substrate (100) and a composite ink layer (200). The glass substrate (100) has an inner surface (110) and an outer surface (120) with opposite sides. A local area of ​​the substrate is formed by the inner surface (110) and the outer surface (120) being recessed inward simultaneously to form a boss structure (130) that protrudes outward from the main body of the glass substrate (100). The inner surface (110) has a flat portion (111) and a recessed portion formed by the boss structure (130). The recessed portion includes a flat bottom (112) and an annular sidewall portion (113). A first end of the sidewall portion (113) is connected to the flat bottom (112), and a second end is connected to the flat portion (111) to form an annular transition area. The maximum width of the annular transition area in the horizontal plane is greater than 20 mm. The composite ink layer (200) includes a plurality of sub-ink layers formed sequentially on the inner surface (110); The method includes the following steps: Each sub-ink layer is sequentially formed in the recessed area using a pad printing process; Each sub-ink layer is formed sequentially using a screen printing process on the flat portion (111); The sub-ink layer formed by the pad printing process and the sub-ink layer formed by the screen printing process form an overlapping area near the second end of the sidewall portion (113).

2. The method for preparing a glass cover plate according to claim 1, characterized in that, The composite ink layer (200) comprises, in order of increasing distance from the inner surface (110), a main color layer (210), a masking layer (220), a light-shielding layer (230), and an adhesive layer (240); the main color layer (210) is used to provide color effects, the masking layer (220) is used to provide a highly reflective background for the main color layer (210), the light-shielding layer (230) is used to prevent stray light interference, and the adhesive layer (240) is used to enhance the bonding strength with the metal frame.

3. The method for preparing a glass cover plate according to claim 2, characterized in that, The main color layer (210) includes a first color layer (211) and a second color layer (212). The first color layer (211) covers the inner surface (110), and the second color layer (212) covers the side of the first color layer (211) away from the inner surface (110).

4. The method for preparing a glass cover plate according to claim 3, characterized in that, An annular ink layer (250) is also provided between the first color layer (211) and the second color layer (212) on the flat portion (111), the annular ink layer (250) being disposed along the edge of the first color layer (211).

5. The method for preparing a glass cover plate according to claim 2, characterized in that, The light-shielding layer (230) includes a first light-shielding layer (231) and a second light-shielding layer (232). The first light-shielding layer (231) covers the shielding layer (220), and the second light-shielding layer (232) covers the side of the first light-shielding layer (231) away from the shielding layer (220).

6. The method for preparing a glass cover plate according to claim 2, characterized in that, The flat bottom (112) is provided with at least one through hole (114), and the method of preparing the glass cover plate further includes: transferring the main color layer (210) on the side wall of the through hole (114).

7. The method for preparing a glass cover plate according to any one of claims 1 to 6, characterized in that, The execution sequence of each process in pad printing and screen printing is as follows: Each sub-ink layer is screen-printed sequentially on the flat surface. After each layer is screen-printed, a pre-curing process is performed before screen-printing the next layer. At least one outermost sub-ink layer is reserved to be applied after the transfer printing is completed. Each sub-ink layer is sequentially transferred into the recessed area. After each layer is transferred, a pre-curing treatment is performed before transferring the next layer. The glass cover is cleaned using a plasma cleaner to remove dirt adsorbed on the inner surface. The reserved sub-ink layer is screen-printed on the flat area, then pre-cured, and then the next layer is screen-printed until all screen-printing processes are completed, and then the final curing process is performed.

8. The method for preparing a glass cover plate according to any one of claims 1 to 6, characterized in that, The execution sequence of each process in pad printing and screen printing is as follows: The first sub-ink layer is screen-printed on the flat portion and then pre-cured. The remaining sub-ink layer pad printing and screen printing processes are cross-combined and arranged: the pad printing process of one sub-ink layer and the screen printing process of one sub-ink layer are combined as one process combination. After the process combination is completed, a pre-curing treatment is performed. Then the next process combination is executed, and a pre-curing treatment is performed after the next process combination is completed, and so on. A process combination or an independent process is reserved at the end. Redundant screen printing or pad printing processes are grouped separately and pre-cured separately. Perform the reserved process combination or independent process, and then carry out the final curing treatment.

9. The method for preparing a glass cover plate according to claim 8, characterized in that, For process combinations, the pre-curing time should not be less than the maximum value of the pre-curing time required for each process in the combination.

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