Method for electroplating film layer on IR printing ink

Abstract

The invention discloses a method for electroplating a film layer on IR printing ink, and belongs to the technical field of glass processing. According to the scheme, the baking temperature is increased in the baking link after screen printing of the IR printing ink, and the adhesive force of the IR printing ink and the glass substrate is enhanced; in the electroplating process, an electroplating machine table is heated to 120 DEG C or above, heat preservation is conducted on a product for 10-20 minutes, then a film layer is electroplated on IR printing ink in a constant-temperature heating environment, it is ensured that the IR printing ink and the film layer are fully expanded at the high temperature, accumulation of thermal stress is reduced, the bottom layer of the film layer is made of a material which is good in binding force with the IR printing ink, and therefore the service life of the film layer is prolonged. The adhesive force between the film layer and IR printing ink is improved; and then, the baking temperature of the silk-screen link after electroplating is reduced, so that the baking temperature is closer to the electroplating temperature, the stress effect between the IR ink and the film layer caused by temperature difference is reduced, and the generation of cracks is further reduced. The crack phenomenon of the IR printing ink in the high-temperature baking process is effectively reduced, and the quality and reliability of the product are improved.

Description

Technical Field

[0001] The invention relates to the technical field of glass processing, and in particular to a method for electroplating a film layer on IR ink. Background Art

[0002] In the production and processing of mobile phone camera lenses, mobile phone covers, etc., it is usually necessary to perform multiple steps of processing on the glass substrate to obtain the desired optical and appearance effects. The specific steps include:

[0003] 1. Screen printing IR (Infrared Reflective) ink: Screen printing IR ink on glass substrate to achieve specific optical properties.

[0004] 2. Electroplating film layer: Electroplating is performed on the IR ink to form a dielectric film layer to provide color decoration or enhance the reflection or transmission performance of the lens. The electroplating process is usually carried out at room temperature.

[0005] 3. Silk screen printing cover bottom: Silk screen printing is performed again on the electroplated film layer to form a cover bottom layer to protect the film layer and provide the required appearance effect. The baking temperature after silk screen printing is usually above 150℃, and the baking time is generally 30 minutes.

[0006] However, this traditional production process has the following problems: During the screen printing baking process, the IR ink and the film layer expand together due to heat. Since the thermal expansion coefficient of the IR ink is much larger than that of the film layer, the IR ink is prone to cracks under the action of thermal stress, such as Figure 1 The figure shows a schematic diagram of IR ink cracks at the camera hole. In actual production, it is found that the probability of cracks is very high and the crack phenomenon is very obvious. This not only affects the appearance quality of the product, but also may reduce its optical performance and service life.

[0007] Therefore, it is necessary to propose a new production process or material processing method to reduce or eliminate the cracking phenomenon of IR ink during high-temperature baking and improve the quality and reliability of the product. Summary of the invention

[0008] The technical problem to be solved by the present invention is: in view of the above-mentioned defects of the prior art, a method for electroplating a film layer on IR ink is provided.

[0009] To achieve the above object, the present invention provides a method for electroplating a film layer on IR ink, the method comprising the following steps:

[0010] Step S1, screen printing IR ink on a glass substrate;

[0011] Step S2, silk screen baking, the baking temperature is higher than the normal baking temperature;

[0012] Step S3, placing the glass substrate into an electroplating machine, turning on the heating function of the electroplating machine, heating the temperature in the machine to a first temperature, the first temperature being ≥120° C., and then maintaining the constant temperature for 10 minutes to 20 minutes, and then electroplating a film layer on the IR ink, the film layer being a laminated structure, and a layer closest to the IR ink in the laminated structure is made of a material having good bonding strength with the IR ink; the entire process of electroplating the film layer is carried out in a constant temperature heating environment;

[0013] Step S4, continuing the subsequent silk screen printing process, the baking temperature after the silk screen printing process is a second temperature, the second temperature is lower than the normal baking temperature, and the baking time is longer than the normal baking time;

[0014] The difference between the second temperature and the first temperature is less than 20°C.

[0015] Preferably, the method further comprises:

[0016] Step S5, removing the unnecessary film layer by stripping, wherein the stripping temperature is higher than the conventional stripping temperature, and / or the stripping time is longer than the conventional stripping time.

[0017] Preferably, in step S3, while turning on the heating function of the electroplating machine, the electroplating machine is evacuated. When the vacuum degree is ≤3.0*10^-5Torr, the ion source is started to perform ion cleaning. After the cleaning is completed, the vacuum is continued to reach a vacuum degree of 2.0*10^-5Torr.

[0018] Preferably, in step S3, when the vacuum degree reaches 2.0*10^-5 Torr and the constant temperature is maintained for 10 minutes to 20 minutes, the coating is started.

[0019] Preferably, in step S3, the specific parameters of the electroplating film layer on the IR ink are:

[0020] The electron gun voltage is 90-120V, the current is 6-10A, and the oxygen flow rate is 20-40SCCM.

[0021] The present invention has the following beneficial effects: in the baking process after screen printing IR ink, the present solution enhances the adhesion between IR ink and glass substrate by increasing the baking temperature; in the electroplating process, the electroplating machine is heated to above 120°C, and the product is kept at this temperature for 10 minutes to 20 minutes, and then the film layer is electroplated on the IR ink under a constant temperature heating environment, ensuring that the IR ink and the film layer fully expand at high temperature, reducing the accumulation of thermal stress, and the bottom layer of the film layer adopts a material with good bonding strength with the IR ink to improve the adhesion between the film layer and the IR ink; then the baking temperature of the screen printing process after electroplating is reduced to make it closer to the electroplating temperature, reducing the stress effect between the IR ink and the film layer caused by the temperature difference, and further reducing the generation of cracks. Through the above-mentioned improvement measures, the present invention effectively reduces the crack phenomenon of IR ink during high-temperature baking, and significantly improves the quality and reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 Schematic diagram of IR ink cracks.

[0024] Figure 2 A schematic diagram of the steps of a method for electroplating a film layer on IR ink provided in an embodiment of the present invention.

[0025] Figure 3 A schematic diagram of the processing process of the mobile phone camera lens and the surrounding area provided in Example 1 of the present invention.

[0026] Figure 4 A schematic diagram of the processing process of the mobile phone camera lens and the surrounding area provided in Example 2 of the present invention.

[0027] Figure 5 This is a schematic diagram of the crack effect of Example 2. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of the specification. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0030] The solution of the present invention is suitable for the scenario of electroplating a film layer on IR ink, and can be applied to the production process of camera lenses and mobile phone covers. In addition, because the expansion coefficient of IR ink and ordinary ink is not much different, the solution of the present invention can also be extended to the scenario of electroplating a film layer on ink, and the ink includes IR ink and ordinary ink.

[0031] like Figure 1 As shown, an embodiment of the present invention provides a method for electroplating a film layer on IR ink, characterized in that the method comprises the following steps:

[0032] Step S1, screen printing IR ink on a glass substrate.

[0033] Step S2, screen printing baking, the baking temperature is higher than the normal baking temperature.

[0034] In actual applications, due to different application scenarios, there may be other screen printing processes between step S1 and step S2. After step S2, it is usually necessary to first perform ultrasonic cleaning on the screen-printed glass substrate before starting step S3.

[0035] In step S2, the baking temperature is higher than the conventional baking temperature in order to make the baking more complete so as to enhance the adhesion between the IR ink and the glass substrate.

[0036] Step S3, placing the glass substrate into an electroplating machine, turning on the heating function of the electroplating machine, heating the temperature in the machine to a first temperature, wherein the first temperature is ≥120°C, and then maintaining the constant temperature for 10 minutes to 20 minutes, and then electroplating a film layer on the IR ink, wherein the film layer is a laminated structure, and a layer closest to the IR ink in the laminated structure is made of a material having good bonding with the IR ink; the entire process of electroplating the film layer is carried out in a constant temperature heating environment.

[0037] In practical applications, there are many purposes for electroplating film layers, such as IR anti-reflection, IR color or hiding effects. The layer closest to the IR ink in the stack uses a material that has good bonding with the IR ink, which can make the film layer have better adhesion with the IR ink. For example, when electroplating a color film or a bottom AR film, the bonding between titanium oxide material and IR ink is better than that between silicon oxide material. The structure of the film layer needs to be designed according to the optical simulation results and actual test conditions, and the optical performance of the film layer is met while ensuring the adhesion between the film layer and the IR ink.

[0038] In the prior art, electroplating is usually performed at room temperature without heating the electroplating machine. However, at room temperature, neither the IR ink nor the film layer expands. In the subsequent screen printing baking process, the IR ink and the film layer expand together due to heat. Since the thermal expansion coefficient of the IR ink is much larger than that of the film layer, the IR ink is prone to cracks under the action of thermal stress. The screen printing temperature is generally 150°C or above. Therefore, in the embodiment of the present invention, the machine temperature is heated to above 120°C to make it as close to the screen printing temperature as possible, so that the IR ink and the film layer material are combined under full expansion, avoiding cracks due to stress in the subsequent screen printing baking process.

[0039] Compared with sputtering coating, evaporation coating is more prone to fading, so the electroplating machine commonly used in glass processing is the evaporation coating machine. Evaporation coating machines include diffusion pump machines and cryogenic pump machines. The temperature of the diffusion pump machine can be heated to 150°C or higher, which is close to the temperature range of silk screen printing. However, most diffusion pump machines have been eliminated at present, and most of the machines used in production environments are cryogenic pump machines. The maximum heating temperature of the cryogenic pump machine is generally around 120°C. Too high a temperature will create a risk of regeneration. Because the scheme of the present invention has high requirements on the heating temperature of the cryogenic pump machine, it is necessary to strictly carry out regular maintenance of the cryogenic pump machine, regularly replace new heating lamps, and ensure the accuracy of the temperature sensing probe.

[0040] The electroplating process has very high requirements for cleanliness. In the embodiment of the present invention, in the step S3, while the heating function of the electroplating machine is turned on, the electroplating machine is evacuated. When the vacuum degree is ≤3.0*10^-5Torr, the ion source is started for ion cleaning. After the cleaning is completed, the vacuum is continued to be evacuated to a vacuum degree of 2.0*10^-5Torr. When the vacuum degree reaches 2.0*10^-5Torr and the constant temperature is maintained for 10 minutes to 20 minutes, the coating is started again.

[0041] In the embodiment of the present invention, in step S3, the specific parameters of the electroplating film layer on the IR ink are:

[0042] The electron gun voltage is 90V-120V, the current is 6-10A, and the oxygen flow rate is 20-40SCCM.

[0043] Step S4, continuing the subsequent silk screen printing process, the baking temperature after the silk screen printing process is a second temperature, the second temperature is lower than the normal baking temperature, and the baking time is longer than the normal baking time.

[0044] The difference between the second temperature and the first temperature is less than 20°C.

[0045] In practical applications, the baking temperature in step S4 can be controlled at about 140°C, making it closer to the electroplating temperature. The temperature difference between the screen printing baking temperature after electroplating and the electroplating temperature is controlled within 20°C. Within this temperature difference range, the IR ink will basically not produce cracks. Because the baking temperature is lowered, the baking time needs to be extended accordingly to achieve the purpose of curing the screen printing effect and enhancing the adhesion between the layers.

[0046] In some embodiments of the present invention, the method further comprises:

[0047] Step S5, removing the unnecessary film layer by stripping, wherein the stripping temperature is higher than the conventional stripping temperature and / or the stripping time is longer than the conventional stripping time.

[0048] In some embodiments of the present invention, after the film layer is electroplated, it is necessary to remove the film layer from the parts that are not needed for the product by stripping. Because the film layer is electroplated in a heated environment and the baking time is increased during the silk screen baking process after electroplating, the stripping temperature needs to be increased accordingly and / or the stripping time needs to be extended during stripping to ensure the stripping effect.

[0049] Because the temperature is precisely controlled during the electroplating process and the silk screen baking process after electroplating, the IR ink and the film layer are fully expanded. After baking, the IR ink and the film layer shrink naturally during the cooling process, and the film layer will not produce outward tensile stress on the IR ink. Therefore, the IR ink will not crack during the cooling process.

[0050] The solution of the present invention is described in detail below in conjunction with two specific embodiments.

[0051] Example 1

[0052] like Figure 3 As shown, it is a schematic diagram of some process links in the production process of the mobile phone glass camera lens and the surrounding area provided in Example 1, which specifically includes the following links:

[0053] 1. Two layers of IR ink are screen printed on the entire back of the glass substrate, and a camera hole is reserved in the IR ink layer. Figure 3 As shown, four circular camera holes are reserved on each layer of IR ink.

[0054] 2. Screen print the first black background on the IR ink, and reserve holes for IR ink, camera, and CD. Figure 3 As shown, there are 4 IR ink holes, 4 camera holes, and 4 CD pattern holes on the first black matrix. IR ink can be exposed through the IR oil holes.

[0055] 3. Silk screen CD pattern on the first black background.

[0056] 4. Electroplating a color film on the entire CD pattern, the color film is a decorative film for the CD pattern. Because the CD pattern and the IR oil hole are very close, it is impossible to cover the IR oil hole by applying a protective film, so the purpose of electroplating a color film on the CD pattern is achieved by electroplating the color film on the entire surface and then fading the color film.

[0057] 5. Screen print the second black matrix on the color film, and the second black matrix has reserved holes for IR oil and camera. Figure 3 As shown, four IR oil holes and four camera holes are reserved on the second black substrate.

[0058] 6. Remove the color film on the IR oil hole and the camera hole to ensure the transmittance of the IR oil hole and the camera hole.

[0059] According to the conventional coating method in the prior art, after stripping, cracks of the IR ink will be seen from the IR oil holes.

[0060] In the embodiment of the present invention, the following method is used to complete the above process steps:

[0061] Step S1, screen printing two layers of IR ink on the back of the glass substrate, wherein the IR ink has a camera hole reserved therein; after the first layer of IR ink is screen printed, it is sent into a tunnel furnace and dried at 150° C. for 5 minutes; after the second layer of IR ink is screen printed, it is sent into a tunnel furnace and dried at 150° C. for 10 minutes.

[0062] Step S2, screen print the first black matrix on the upper layer of IR ink, the first black matrix is ​​reserved with IR oil holes, camera holes, and CD pattern holes, and sent to the tunnel furnace, and dried at 150℃ for 10 minutes. Screen print CD pattern on the first black matrix, and then bake at 160℃ for 30 minutes. In this step, the baking temperature is deliberately increased from 150℃ to 160℃ to enhance the adhesion between IR ink and glass substrate. After baking, the product is ultrasonically cleaned.

[0063] Step S3, while ensuring the cleanliness of the surface to be electroplated, use the Korean vacuum coating machine UNIVAC2050 to evacuate and heat at the same time. When the vacuum reaches 3.0-10^-5Torr, start the ion source for ion cleaning for 5 minutes, and fill the ion source with 10SCCM of oxygen and 20SCCM of argon; after cleaning, continue to vacuum and wait. When the vacuum reaches 2.0*10^-5Torr and the heating time is more than 35 minutes, start the color film coating. When the heating time is more than 35 minutes, it can ensure that the product is kept at a constant temperature of 120℃ for more than 15 minutes. The first layer is made of titanium oxide as the base, and the remaining layers are titanium oxide or silicon oxide. During electroplating, the electron gun voltage is 110V, the current is 8A, and the oxygen filling flow rate is 30SCCM. After plating titanium oxide, electroplate other film layers in turn to ensure that the electroplating film layer process is carried out in a constant temperature heating environment, so that the electroplated film layer and IR oil are fully expanded to avoid the formation of film layer stacking and cracks in the subsequent heating process.

[0064] The base layer of the color film and AR film is usually made of silicon oxide, but through optical simulation, it can be found that removing the silicon oxide base layer does not affect the optical properties of the color film and AR film. Therefore, titanium oxide is used as the base layer in this embodiment, and the titanium oxide base layer serves as both the base layer and the effective layer of the color film.

[0065] The solution of the embodiment of the present invention has relatively high requirements for the maintenance and heating of the low-temperature pump of the evaporation machine. Usually, a newly maintained machine that has passed the temperature control function verification of the machine is used. In addition to the temperature control function, it is also necessary to verify whether the vacuum and cleanliness of the evaporation machine meet the specified requirements.

[0066] Step S4, screen printing the second black matrix on the color film, the baking temperature after screen printing is 140 degrees Celsius, and the baking time is 35 minutes. In this step, the baking temperature is reduced from 150 degrees Celsius to 140 degrees Celsius, and the baking time is extended from 30 minutes to 35 minutes.

[0067] Step S5, remove the color film in the IR oil hole and the camera hole, and adjust the stripping parameters from 70°C, 120 seconds to 85°C, 240 seconds. The single stripping time should not exceed 60 seconds, and rinse with clean water once between each stripping.

[0068] Example 2

[0069] like Figure 3 As shown, it is a schematic diagram of some process links in the production process of the mobile phone glass camera lens and the surrounding area provided in Example 2, which specifically includes the following links:

[0070] 1. The CD pattern is silk-screened in the rectangular area on the left, and the three hollow areas are camera holes.

[0071] 2. Print the first layer of IR ink in the rectangular area on the right. The three holes from top to bottom are the flash hole, Moca hole, and Mic hole.

[0072] 3. Screen print the second layer of IR ink in the rectangular area on the right.

[0073] 4. Print the first layer of black ink in the rectangular area on the right. The four holes from top to bottom are the flash hole, laser hole, Moca hole, and Mic hole. The second layer of IR ink is exposed from the hollow laser hole.

[0074] 5. Print a layer of varnish on the laser hole. Because the IR ink exposed in the laser hole is easy to fall off during the cleaning process, varnish is printed on the IR ink of the laser hole. IR ink is an optical ink prepared by adding colored ingredients to varnish, and its main component is still varnish. Therefore, the expansion coefficients of varnish and IR ink are almost the same.

[0075] 6. The whole surface is electroplated with color film.

[0076] 7. Silk screen printed LOGO.

[0077] 8. Silk screen print the second layer of black ink. During the silk screen printing process, all functional holes are hollowed out.

[0078] 9. Silk screen the third layer of black ink.

[0079] 10. De-plating the color films on all functional holes.

[0080] The difference between Example 2 and Example 1 is that after printing varnish on the IR ink, a color film is electroplated on the varnish. The electroplated color film is also a laminated structure of titanium oxide and silicon oxide. Because the expansion coefficients of varnish and IR ink are similar, if the varnish and the color film are not heated during the electroplating process, the varnish and the color film cannot be fully expanded. During the heating process of the screen printing link, the varnish expands faster than the color film, and the color film generates an outward pulling stress on the varnish, causing cracks in the varnish.

[0081] During the production process, the product described in Example 2 was produced simultaneously in 5 workshops, namely A, B, C, D, and E, according to the above process. Among them, the temperatures when electroplating the color film in workshop A and workshop B were 120°C and 110°C, respectively. As in Example 1, the baking temperature was increased in the silk-screen printing step before electroplating, and the baking temperature was reduced and the baking time was extended in the silk-screen printing step after electroplating. During stripping, the stripping temperature was increased and the stripping time was extended. The electroplating process in workshops C, workshop D, and workshop E was not heated, and the silk-screen printing step before electroplating, the silk-screen printing step after electroplating, and the stripping step were all carried out according to conventional process parameters. The film layer structure of the color film in each workshop is consistent. After statistics, it was found that the crack incidence rates after stripping in workshops A, B, C, D, and E were 0%, 3%, 100%, 80%, and 70%, respectively. The crack effects are as follows. Figure 5 As shown. It can be seen that, because the expansion coefficient of varnish is substantially the same as that of IR ink, based on the same principle as in Example 1, the solution of the present invention is also applicable to electroplating a film layer on varnish to reduce the cracking rate of ink.

[0082] The present invention has the following beneficial effects: in the baking process after screen printing IR ink, the present solution enhances the adhesion between IR ink and glass substrate by increasing the baking temperature; in the electroplating process, the electroplating machine is heated to above 120°C, and the product is kept at this temperature for 10 minutes to 20 minutes, and then the film layer is electroplated on the IR ink under a constant temperature heating environment, ensuring that the IR ink and the film layer fully expand at high temperature, reducing the accumulation of thermal stress, and the bottom layer of the film layer adopts a material with good bonding strength with the IR ink to improve the adhesion between the film layer and the IR ink; then the baking temperature of the screen printing process after electroplating is reduced to make it closer to the electroplating temperature, reducing the stress effect between the IR ink and the film layer caused by the temperature difference, and further reducing the generation of cracks. Through the above-mentioned improvement measures, the present invention effectively reduces the crack phenomenon of IR ink during high-temperature baking, and significantly improves the quality and reliability of the product.

[0083] The above are only specific implementations of the present invention, which cannot be used to limit the scope of the present invention. Equivalent changes made by ordinary technicians in this technical field based on this creation, as well as changes known to technicians in this field, should still fall within the scope of the present invention.

Claims

1. A method for electroplating a film layer on IR ink, characterized in that: The method comprises the following steps: Step S1, screen printing IR ink on a glass substrate; Step S2, silk screen baking, the baking temperature is higher than the normal baking temperature; Step S3, placing the glass substrate into an electroplating machine, turning on the heating function of the electroplating machine, heating the temperature in the machine to a first temperature, the first temperature being ≥120° C., and then maintaining the constant temperature for 10 minutes to 20 minutes, and then electroplating a film layer on the IR ink, the film layer being a laminated structure, and a layer closest to the IR ink in the laminated structure is made of a material having good bonding strength with the IR ink; the entire process of electroplating the film layer is carried out in a constant temperature heating environment; Step S4, continuing the subsequent silk screen printing process, the baking temperature after the silk screen printing process is a second temperature, the second temperature is lower than the normal baking temperature, and the baking time is longer than the normal baking time; The difference between the second temperature and the first temperature is less than 20°C.

2. The method for electroplating a film layer on IR ink according to claim 1, characterized in that: The method further comprises: Step S5, removing the unnecessary film layer by stripping, wherein the stripping temperature is higher than the conventional stripping temperature, and / or the stripping time is longer than the conventional stripping time.

3. The method for electroplating a film layer on IR ink according to claim 1, characterized in that: In step S3, while turning on the heating function of the electroplating machine, the electroplating machine is evacuated. When the vacuum degree is ≤3.0*10^-5Torr, the ion source is started to perform ion cleaning. After the cleaning is completed, the vacuum is continued to reach a vacuum degree of 2.0*10^-5Torr.

4. The method for electroplating a film layer on IR ink according to claim 3, characterized in that: In step S3, when the vacuum degree reaches 2.0*10^-5 Torr and the constant temperature is maintained for 10 minutes to 20 minutes, the coating is started.

5. The method for electroplating a film layer on IR ink according to claim 3, characterized in that: In step S3, the specific parameters of the electroplated film layer on the IR ink are: The electron gun voltage is 90-120V, the current is 6-10A, and the oxygen flow rate is 20-40SCCM.

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