Ultrathin ink processing method

Abstract

The invention discloses a processing method of ultrathin ink. The processing method comprises the following steps: 1) cleaning a coiled material; (2) ink jetting; (3) pre-baking; 4) exposing; 5) developing; (6) post-baking or photo-curing; 7) film covering; and (8) cutting, ink jet is used for replacing silk-screen printing, the efficiency is high, the ink thickness is more uniform and thinner, a product manufactured through the yellow light technology is high in pattern precision, the pattern edge is neat, sawteeth are avoided, and the ink performance in all aspects can meet the standard requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of OLED displays, and particularly relates to a method for processing ultra-thin ink. Background Art

[0002] In the process of implementing the present invention, the inventor found that the prior art has at least the following problems:

[0003] With the continuous innovation of technology, the recognition of folding-screen mobile phones has increased, and folding-screen mobile phones have gradually entered the mass market. The price reduction can attract more potential consumers and accelerate the popularization of folding-screen mobile phones in the Chinese market. Compared with straight-screen mobile phones, folding-screen mobile phones are more technological, and users pay more attention to the innovation of the intelligent system and the quality of mobile phones.

[0004] However, since the release of folding-screen mobile phones, numerous serious problems have occurred, such as screen breakage and liquid leakage, which have rendered the mobile phones unable to be used normally. In addition, the initial internal folding double-screen design of Samsung's Galaxy Fold, such as, made the body very thick, and the external screen was almost "unusable" due to the aspect ratio problem; Coincidentally, although the external folding scheme adopted by Mate X avoided the above problems, since the surface of the foldable screen must use flexible materials, the screen was very non-abrasive, and the external folding scheme made the screen exposed for a long time, and the problem of scratches caused by friction was much more serious.

[0005] Using screen printing to print the required pattern on the PET printing surface, the ink thickness has been maintained at 3-4 um, and the pattern has large serrations and poor graphic consistency. After bonding with the glass, the PV value of the camera hole is about 1.5, which seriously does not meet the customer's standards, and will cause the edge of the camera hole to be blurred when taking pictures; Secondly, the PET ink produced by screen printing has a large step difference, which will cause bubbles that cannot be removed after bonding, and 25 um OCA cannot be used, which will cause the mobile phone to be unable to be lightweight.

[0006] CN107118613A - An ink, an OLED border printed with the ink and a preparation method thereof, discloses an ink, an OLED border printed with the ink and a preparation method thereof. In this solution, the ink is composed of a thermosetting resin, carbon black dye, solvent, thickener and matting agent in a preset weight percentage, and it also cannot solve the above technical problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for processing ultra-thin ink, using inkjet instead of screen printing, which is not only efficient, but also has a more uniform and thinner ink thickness. The product made by the yellow light process has high graphic accuracy, neat pattern edges and no serrations, and the ink performance in all aspects can meet the standard requirements.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is: an ultra-thin ink processing method, including the following steps: 1) Coil cleaning; 2) Inkjet printing; 3) Pre-baking; 4) Exposure; 5) Development; 6) Post-baking or photocuring; 7) Film laminating; 8) Cutting.

[0009] In the above step 1), the PET surface dirt and foreign matters are cleaned using plasma.

[0010] In the above step 2), a high-precision inkjet printing device is adopted, the nozzle is micron-level positioned, the inkjet height is adjusted by a computer control system to be within 0.5 - 1 mm, the position accuracy is within ±0.05 mm, the pressure is 0.3 - 0.5 MPa, the ink flow rate and the nozzle state are monitored in real time, and the ink thickness on the PET surface is 1 - 2 um.

[0011] In the above step 3), the ink is pre-solidified through pre-baking, the baking temperature is lower than the ink curing temperature, and the baking time is 30 - 50 minutes.

[0012] In the above step 4), a combination of DI exposure and film exposure is adopted. In DI exposure, a high-precision laser is used to draw the required pattern, and film exposure is used for assistance. The exposure time is 30 - 40 seconds, so that the photosensitive ink undergoes a photochemical reaction to generate a pattern outline.

[0013] In the above step 5), a developer is used to wash away the unexposed ink by spraying or soaking. The temperature of the developer is controlled at 25 - 30 °C, the spraying pressure is 0.2 - 0.3 MPa, the soaking time is 3 - 5 minutes, and then deionized water is used to rinse the residual developer to keep the PET surface clean.

[0014] In the above step 6), for thermosetting ink, a process with a temperature higher than the pre-baking temperature is used to crosslink and cure it; for photocurable ink, a high-intensity ultraviolet light curing device is used to cure the ink, the light intensity is 100 - 150 mW / cm 2 , and the irradiation time is 60 - 90 seconds.

[0015] In the above step 7), a 10 - 50 um PE or PET protective film is laminated on the cured PET surface.

[0016] In the above step 8), a laser cutting device is used to cut the laminated PET coil into small pieces according to the product size for use in folding screen mobile phones.

[0017] One of the above technical solutions has the following advantages or beneficial effects. Using inkjet printing instead of screen printing not only has high efficiency, but also the ink thickness is more uniform and thinner. The product graphics made by the yellow light process have high precision, the pattern edges are neat and without serrations, and the ink performance in all aspects can meet the standard requirements. Description of the Drawings

[0018] Figure 1This is the schematic diagram of the ultra-thin ink processing method provided in the embodiments of the present invention; Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] Embodiment 1

[0021] Refer to Figure 1 , an ultra-thin ink processing method, including the following steps: 1) Coil cleaning; 2) Inkjet printing; 3) Pre-baking; 4) Exposure; 5) Development; 6) Post-baking or photocuring; 7) Laminating; 8) Cutting.

[0022] In the above step 1), coil cleaning: Use plasma to clean the dirt and foreign matters on the surface of PET. Plasma cleaning can effectively remove organic pollutants, dust particles, etc. on the surface of PET through physical and chemical actions, improve the cleanliness and activity of the PET surface, enhance the adhesion between the subsequent ink and the PET surface, and lay a foundation for high-quality ink printing.

[0023] In the above step 2), inkjet printing: Adopt a high-precision inkjet device, with micron-level positioning of the nozzle, and the computer control system adjusts the inkjet height within 0.5 - 1 mm, the position accuracy within ±0.05 mm, and the pressure of 0.3 - 0.5 MPa. The ink flow rate and the nozzle state are monitored in real time to make the ink thickness on the PET surface 1 - 2 um. Micron-level nozzle positioning and high-precision position control ensure that the ink is accurately jetted to the specified position on the PET surface, avoiding pattern distortion or deviation; controlling the inkjet height and pressure ensures that the ink is jetted in a suitable form and speed to form a uniform ink layer; real-time monitoring of the ink flow rate and the nozzle state can promptly detect and solve problems such as nozzle clogging and abnormal ink supply, improving production stability; controlling the ink thickness within 1 - 2 um meets the requirements of the subsequent process for the ink layer thickness, ensuring pattern clarity and accuracy.

[0024] In the above step 3), pre-baking: The ink is pre-solidified through pre-baking, and the baking temperature is lower than the ink curing temperature, and it is baked for 30 - 50 minutes. Pre-baking preliminarily fixes the ink on the PET surface, prevents the ink from shifting or bleeding in the subsequent processes, and at the same time retains the activity of the photosensitive components of the ink; baking at a temperature lower than the curing temperature avoids over-curing of the ink and affecting the photochemical reaction; a baking time of 30 - 50 minutes ensures that the ink is fully pre-solidified, and also prevents the PET material from deforming or the ink performance from being damaged, improving the product qualification rate and quality stability.

[0025] In the above step 4), exposure: DI exposure and film exposure are combined. For DI exposure, a high-precision laser is used to draw the required pattern, and film exposure is used as an auxiliary. The exposure time is 30 - 40 seconds, enabling the photoreaction of the photosensitive ink to generate a pattern outline. DI exposure uses a high-precision laser to achieve high-resolution pattern production, meeting the requirements of high-end products for fine patterns; film exposure as an auxiliary makes up for the deficiencies of DI exposure in the processing of large-area patterns or the edges of complex graphics; the 30 - 40-second exposure time ensures that the photosensitive ink reacts fully, forming a clear and accurate pattern outline, and avoiding pattern quality problems caused by insufficient or excessive exposure.

[0026] In the above step 5), development: A developer is used to wash away the unexposed ink by spraying or immersion. The temperature of the developer is controlled at 25 - 30°C, the spraying pressure is 0.2 - 0.3 MPa, and the immersion time is 3 - 5 minutes. Then, deionized water is used to rinse the residual developer to ensure the cleanliness of the PET surface. The spraying or immersion method allows the developer to come into full contact with the unexposed ink, improving the development effect; controlling the temperature, pressure, and immersion time of the developer ensures the development efficiency and quality, and avoids damaging the PET surface and the formed pattern; rinsing the residual developer with deionized water prevents it from having an adverse effect on the subsequent curing process, ensuring the pattern quality and durability.

[0027] In the above step 6), post-baking or photocuring: For thermosetting inks, a process with a temperature higher than the pre-baking temperature is used to crosslink and cure them; for photocuring inks, a high-intensity ultraviolet photocuring device is used to cure the ink, with a light intensity of 100 - 150 mW / cm 2 , and the irradiation time is 60 - 90 seconds. The thermosetting process promotes the crosslinking of thermosetting ink molecules to form a strong cured film, improving the ink adhesion, abrasion resistance, and chemical stability; high-intensity ultraviolet irradiation enables the rapid and complete curing of photocuring inks. The cured ink layer has good hardness, gloss, and weather resistance, meeting the strict requirements of folding screen mobile phones for pattern quality and durability.

[0028] In the above step 7), laminating: A 10 - 50 μm PE or PET protective film is laminated on the cured PET surface. The protective film has good flexibility, abrasion resistance, and chemical stability, and can protect the cured pattern from scratches, abrasions, contamination, and other damages during subsequent processing, transportation, and use; the 10 - 50 μm thickness can not only ensure the protection performance but also does not affect the flexibility of the PET material and the thin and light design of the mobile phone, and is easy to adhere and peel off without leaving impurities.

[0029] In the above step 8), cutting: Use a laser cutting device to cut the PET roll after laminating into small pieces according to the product size for use in folding screen mobile phones. The high precision of the laser cutting device ensures small cutting size errors, meeting the precise assembly requirements of mobile phone components; the high speed and non-contact processing improve production efficiency and avoid damaging the surface pattern and protective film of the PET; complex shape cutting can be achieved, meeting the diverse design requirements of folding screen mobile phones, with neat and smooth cutting edges, reducing production costs and processing time.

[0030] Adopt the inkjet + yellow light process instead of screen printing. Using inkjet instead of screen printing not only has high efficiency, but also has a more uniform and thinner ink thickness. The product graphics made by the yellow light process have high precision, neat pattern edges and no serrations, and the ink performance in all aspects can meet the standard requirements. Moreover, when laminating, it can accommodate a thinner OCA, which will make the mobile phone develop towards lightweight. At the same time, the PV value of the camera hole is also maintained below 0.75. Compared with the traditional screen printing method, the PV value is reduced by half, perfectly solving the technical problems existing in the existing screen printing. And both inkjet and yellow light operations can be carried out in a dust-free environment, with less contact with foreign objects compared to the screen printing process, effectively reducing the risk of foreign objects.

[0031] Solve some difficulties in the existing PET processing process. Compared with the existing process, it has the following advantages: 1. This method will make the ink on the PET surface more uniform, thinner and lighter, showing a better pattern effect and achieving no serrations. 2. This method will make the PV value of the PET smaller, better meeting customer requirements. 3. The products made by this method have high consistency and high production efficiency. 4. The ink thickness of the PET made by this method and the pattern display effect of the product can easily meet customer requirements by adjusting process parameters. 5. The ultra-thin ink made by this process will enable the laminating section to accommodate a thinner OCA, solving the difficulty that the OCA cannot absorb laminating bubbles due to too large an ink step difference, and will make the production of the entire mobile phone develop towards lightweight.

[0032] After adopting the above structure, using inkjet instead of screen printing not only has high efficiency, but also has a more uniform and thinner ink thickness. The product graphics made by the yellow light process have high precision, neat pattern edges and no serrations, and the ink performance in all aspects can meet the standard requirements.

[0033] Example 2

[0034] An ultra-thin ink processing method, combining inkjet and yellow light processes, is completed through several steps including coil cleaning, inkjet printing, pre-baking, exposure, development, post-baking / light curing, laminating, and cutting. The specific detailed drawings are attached Figure 1 .

[0035] In the first step, use a plasma cleaning machine to clean the dirt and foreign objects on the PET surface and remove them.

[0036] In the second step, through the inkjet section, high-precision inkjet equipment is used. The nozzle is positioned at the micron level, and the computer control system precisely adjusts the inkjet height to be within 0.5 - 1 mm, the position accuracy within ±0.05 mm, and the pressure at 0.3 - 0.5 MPa. The ink flow rate and the nozzle status are monitored in real time, making the ink thickness on the PET surface controllable and uniform at 1 - 2 μm, which is better than traditional screen printing.

[0037] In the third step, pre-curing of the ink is carried out through pre-baking. The baking temperature is lower than the ink curing temperature, and the baking time is 30 - 50 minutes.

[0038] In the fourth step, a combination of DI exposure and film exposure is adopted. For DI exposure, a high-precision laser is used to draw the required pattern, and film exposure is used as an auxiliary. The exposure time is fine-tuned according to the pattern fineness for 30 - 40 seconds, enabling the photochemical reaction of the photosensitive ink to form the pattern outline.

[0039] In the fifth step, a (TMAH) developer with a precisely adjusted concentration is used to wash away the unexposed ink by spraying or immersion. The temperature of the developer is controlled at 25 - 30 °C, the spraying pressure at 0.2 - 0.3 MPa, and the immersion time at 3 - 5 minutes. After washing, deionized water is used to rinse the residual developer to keep the PET surface clean.

[0040] In the sixth step, for inks that require heat curing, a process similar to pre-baking but at a higher temperature (such as 120 - 130 °C for 20 - 30 minutes) is used to cross-link and cure them; for photo-curable inks, a high-intensity ultraviolet light curing device (light intensity 100 - 150 mW / cm 2 , irradiation time 60 - 90 seconds) is used to ensure complete curing, improving hardness and wear resistance.

[0041] In the seventh step, a 10 - 50 μm PE or PET protective film with good optical properties and strong flexibility is then covered on the cured PET surface to prevent the ink from being scratched and protect the subsequent processes.

[0042] In the eighth step, a high-precision laser cutting device is used to cut the PET film after laminating into small pieces according to the product size, and the cut small pieces are used for the lamination of folding screen mobile phones.

[0043] The entire surface of the product is inkjet-printed, and the ink thickness of the produced product is controllable and has high uniformity. Its entire surface spraying, in-line cutting, exposure, and development process has the ability to be mass-produced, with high production efficiency and better quality. It solves the problem that foreign objects cannot be completely eliminated, and further avoids the uncertainty of manual operations. It can make the ink layer covered on the PET surface thinner, and the ink thickness can be adjusted according to requirements, reducing the impact of too large PV value caused by too large ink step difference on the mobile phone camera hole.

[0044] Some difficult points in the existing PET processing are solved. Compared with the existing processes, it has the following advantages: 1. This method will make the ink on the PET surface more uniform, thinner, show a better pattern effect, and can achieve no serrations. 2. This method will make the PV value of PET smaller and better meet the customer requirements. 3. The products made by this method have high consistency and high production efficiency. 4. The ink thickness of the PET made by this method and the display effect of the product pattern can easily meet the customer requirements by adjusting the process parameters. 5. The ultra-thin ink made by this process will enable the lamination section to accommodate a thinner OCA, solve the difficulty that the OCA cannot absorb the lamination bubbles due to too large ink step difference, and will make the production of the entire mobile phone develop towards light weight.

[0045] After adopting the above structure, using inkjet instead of screen printing not only has high efficiency, but also has a more uniform and thinner ink thickness. The product patterns made by the yellow light process have high precision, the pattern edges are neat and without serrations, and the ink properties in all aspects can also meet the standard requirements.

[0046] The inkjet + yellow light process of the present invention is completed through the above series of processes, replacing the traditional screen printing method. Compared with the previous processing methods, the manufacturing process is simpler and more controllable, the ink thickness is more uniform and thinner, the process is more controllable and easier to automate, the products made have better effects, are more suitable for mass production, and can make the products cleaner, and will not cause too many foreign matters in the products that cannot be solved due to being exposed. The specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inner", "front", "center", "both ends", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0048] In the present invention, unless otherwise clearly specified or limited, terms such as "installation", "setting", "connection", "fixation", "swivel connection" and the like shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. Unless otherwise clearly limited, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-thin ink processing method, characterized in that, It includes the following steps: 1) Coil cleaning; 2) Inkjet printing; 3) Pre-baking; 4) Exposure; 5) Development; 6) Post-baking or photocuring; 7) Laminating; 8) Cutting.

2. The ultra-thin ink processing method according to claim 1, wherein, In the above step 1), the dirt and foreign matters on the PET surface are cleaned using plasma.

3. The ultra-thin ink processing method according to claim 2, characterized in that, In the above step 2), a high-precision inkjet device is adopted. The nozzle is micron-level positioned. The computer control system adjusts the inkjet height to be within 0.5 - 1 mm, the position accuracy within ±0.05 mm, and the pressure to be 0.3 - 0.5 MPa. The ink flow rate and the nozzle state are monitored in real time to make the ink thickness on the PET surface 1 - 2 μm.

4. The ultra-thin ink processing method according to claim 3, wherein In the above step 3), the ink is pre-solidified through pre-baking. The baking temperature is lower than the ink curing temperature, and the baking time is 30 - 50 minutes.

5. The ultra-thin ink processing method according to claim 4, characterized in that, In the above step 4), a combination of DI exposure and film exposure is adopted. In DI exposure, a high-precision laser is used to draw the required pattern, and film exposure is used for assistance. The exposure time is 30 - 40 seconds to make the photosensitive ink undergo a photochemical reaction to generate the pattern outline.

6. The ultra-thin ink processing method according to claim 5, characterized in that, In the above step 5), a developer is used to wash away the unexposed ink by spraying or immersion. The temperature of the developer is controlled at 25 - 30 °C, the spraying pressure is 0.2 - 0.3 MPa, and the immersion time is 3 - 5 minutes. Then, deionized water is used to rinse the residual developer to keep the PET surface clean.

7. The ultra-thin ink processing method according to claim 6, wherein, In the above step 6), for thermosetting inks, use a process with a temperature higher than the pre-baking temperature to crosslink and cure them; for photocuring inks, use a high-intensity ultraviolet photocuring device to cure the inks, with a light intensity of 100-150 mW / cm 2 , and the irradiation time is 60-90 seconds.

8. The ultra-thin ink processing method according to claim 7, characterized in that In the above step 7), a 10 - 50 μm PE or PET protective film is laminated on the cured PET surface.

9. The ultra-thin ink processing method according to claim 8, characterized in that, In the above step 8), a laser cutting device is used to cut the laminated PET coil into small pieces according to the product size for use in folding screen mobile phones.

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