ITO (Indium Tin Oxide) film aging crystallization process and ITO film

Abstract

The invention discloses an ITO (Indium Tin Oxide) film aging crystallization process and an ITO film. The ITO film aging crystallization process comprises the following steps: unwinding a coiled film material at a certain tension; the unwound membrane material is fed into a drying oven to be heated and aged, the aging temperature ranges from 155 DEG C to 160 DEG C, the time ranges from 4 min to 6 min, and the membrane material moves in the drying oven with certain tension; the membrane material is taken out of the drying oven and then rolled with certain tension; wherein the tension of the membrane material in the drying oven is larger than the unwinding tension and smaller than the winding tension. The aging crystallization process provided by the invention can effectively solve the warping problem of the ITO film, and can ensure that the crystallization is qualified and the yield of finished products is high.

Description

Technical Field

[0001] The invention belongs to the technical field of ITO film preparation, and in particular relates to an ITO film aging crystallization process and an ITO film. Background Art

[0002] ITO film, i.e. indium tin oxide film, is also called ITO conductive film. It is widely used in touch products, especially in electronic products such as liquid crystal display screens, touch screens, and flat panel displays. In order to further improve the performance of ITO film, after the ITO layer is plated using vacuum magnetron sputtering technology, other layer structures will be set on the ITO layer. Before setting other layer structures, the ITO layer needs to be aged and crystallized to increase the yield rate.

[0003] At present, the aging and crystallization of the ITO layer is mostly carried out by placing the film material in an infrared oven for aging, and using a conveyor belt to move the film material in the infrared oven. However, this aging and crystallization method is prone to the problem of film warping. Severe warping will cause the ITO film to be unable to be used normally.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide an ITO film aging crystallization process and an ITO film. The aging crystallization process in the present invention can effectively solve the problem of warping of the ITO film and ensure the yield of the finished product.

[0006] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0007] An ITO film aging crystallization process comprises the following steps:

[0008] Unwind the rolled film material at a certain tension;

[0009] The unwound film is sent into an oven for heating and aging at a temperature of 155-160°C for 4-6 minutes. The film moves in the oven with a certain tension.

[0010] After the film comes out of the oven, it is rolled up with a certain tension;

[0011] Among them, the tension of the film material in the oven is greater than the unwinding tension, and less than the winding tension.

[0012] In one or more embodiments of the present invention, the film is unwound at a tension of 200-220N.

[0013] In one or more embodiments of the present invention, the tension of the film in the oven is 250-350N.

[0014] In one or more embodiments of the present invention, the tension of the film material increases step by step by 10-20N in the oven along the moving direction of the film material.

[0015] In one or more embodiments of the present invention, along the moving direction of the film material, the oven is divided into a first tension section, a second tension section and a third tension section, the film material tension in the first tension section is 250-310N, the film material tension in the second tension section is 260-330N, and the film material tension in the third tension section is 280-350N;

[0016] Moreover, the tension of the film material in the first tension section is smaller than that in the second tension section, and the tension of the film material in the second tension section is smaller than that in the third tension section.

[0017] In one or more embodiments of the present invention, the film material is preheated after entering the oven, and the preheating temperature is 100-120°C.

[0018] In one or more embodiments of the present invention, the preheating time of the film material is 0.5 to 1 min.

[0019] In one or more embodiments of the present invention, the film is rolled up at a tension of 360-450N.

[0020] Another specific embodiment of the present invention provides a technical solution as follows:

[0021] The ITO film is prepared by the above-mentioned ITO film aging crystallization process.

[0022] Compared with the prior art, the present invention ages and crystallizes the film material under a certain tension, and controls the aging temperature and time at the same time, thereby effectively solving the warping problem of the ITO film and effectively increasing the yield rate. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only 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 should fall within the scope of protection of the present invention.

[0024] A specific embodiment of the present invention provides an ITO film aging crystallization process, including steps 1-3.

[0025] Step 1: Unwind the film at a certain tension.

[0026] Specifically, after the ITO film is plated with the ITO layer, the film is rolled up first. In the aging and crystallization process, the film is unrolled at a tension of 200 to 220 N to prevent the film from being excessively relaxed and enters the oven at a certain tension for aging and crystallization.

[0027] Step 2, sending the unwound film material into an oven for heating and aging, the aging temperature is 155-160°C, the time is 4-6 minutes, and the film material moves in the oven with a certain tension.

[0028] Specifically, the aging crystallization temperature and time of the film will affect the degree of crystallization of the ITO layer. Too long or too short a time will affect the final performance of the film. By controlling the time for the film to pass through the aging crystallization stage to 4 to 6 minutes and limiting the aging temperature, a better crystallization effect can be obtained, and the warping problem of the film can be effectively solved.

[0029] The tension of the film in the oven is 250-350 N. The oven is a conventional roll-to-roll oven, which uses rollers to convey the film inside. The roll-to-roll oven is equipped with a conventional segmented tension structure, which can make the film have different tensions at different positions in the oven.

[0030] Furthermore, along the direction of film movement, the oven is divided into the first tension section, the second tension section and the third tension section. The film tension in the first tension section is 250-310N, the film tension in the second tension section is 260-330N, and the film tension in the third tension section is 280-350N; and the film tension in the first tension section is less than the film tension in the second tension section, and the film tension in the second tension section is less than the film tension in the third tension section. Passing the film through the oven with different tensions and gradually increasing the tension can better reduce the possibility of warping of the film. In addition, the tension of the film increases step by step by 10-20N in the oven, that is, the tension of the film in the latter tension section is 10-20N greater than the tension in the previous tension section. The film tension increases by a certain amplitude, which can better ensure the yield of the film and reduce the possibility of warping due to excessive tension growth.

[0031] Furthermore, the film material is preheated before entering the oven, the preheating temperature is 100-120°C, and the preheating time is 0.5-1min. The film material is preheated before entering the oven, which can gradually increase the temperature of the film material, reduce the negative impact of the sudden temperature increase, and help reduce the internal stress and warping of the film material.

[0032] Step 3: After the film comes out of the oven, it is rolled up at a certain tension.

[0033] Specifically, winding at a tension of 360 to 450 N can effectively ensure the flatness of the film and further reduce the warping problem.

[0034] Another specific embodiment of the present invention provides an ITO film, which is prepared by the above-mentioned ITO film aging crystallization process.

[0035] The present invention is further described in detail below in conjunction with specific embodiments.

[0036] The ITO films used in the specific embodiments of the present invention and the comparative examples are: the specific structure includes a stacked 50μm thick PET protective layer, a 70nm thick acrylic resin lower coating layer, a 50μm thick PET layer, a 60nm thick acrylic resin upper coating layer, a 10nm thick silica base layer, a 20nm thick silicon-aluminum mixed layer (the silicon-aluminum molar ratio in this layer is 75:25 based on silicon-aluminum atoms) and a 200nm thick ITO layer.

[0037] The oven used in the present invention is a conventional roll-to-roll oven, the interior of which is equipped with a conventional segmented tension structure, and the film material is transported in the oven by the transport rollers inside the oven.

[0038] Example 1

[0039] The rolled film material is unwound at a tension of 200N and then enters the drying oven. The speed of the film material in the drying oven is 6m / min.

[0040] Along the moving direction of the film material, the oven is divided into a preheating section and an aging crystallization section. The temperature of the preheating section is 100°C, and the temperature of the aging crystallization section is 155°C. The time for the film material to pass through the preheating section is 0.8 min, and the time for passing through the aging crystallization section is 5 min.

[0041] Along the moving direction of the film material, the aging crystallization section of the oven is divided into the first tension section, the second tension section and the third tension section according to its average length along its own length direction. The tension of the film material in the first tension section is 310N, the tension in the second tension section is 330N, and the tension in the third tension section is 350N.

[0042] After the film material comes out of the oven, it is rolled up at a tension of 360N, completing the aging and crystallization of the ITO film to obtain the ITO film.

[0043] Example 2

[0044] The rolled film material is unwound at a tension of 210N and then enters the drying oven. The speed of the film material in the drying oven is 7m / min.

[0045] Along the moving direction of the film material, the oven is divided into a preheating section and an aging crystallization section. The temperature of the preheating section is 120°C, and the temperature of the aging crystallization section is 160°C. The time for the film material to pass through the preheating section is 0.7 min, and the time for passing through the aging crystallization section is 4.3 min.

[0046] Along the moving direction of the film material, the aging crystallization section of the oven is divided into the first tension section, the second tension section and the third tension section according to its average length along its own length direction. The tension of the film material in the first tension section is 310N, the tension in the second tension section is 330N, and the tension in the third tension section is 350N.

[0047] After the film material comes out of the oven, it is rolled up at a tension of 400N, completing the aging and crystallization of the ITO film to obtain the ITO film.

[0048] Comparative Example 1

[0049] The rolled film material is unwound at a tension of 200N and then enters the drying oven. The speed of the film material in the drying oven is 4m / min.

[0050] Along the moving direction of the film material, the oven is divided into a preheating section and an aging crystallization section. The temperature of the preheating section is 100°C, and the temperature of the aging crystallization section is 165°C. The time for the film material to pass through the preheating section is 1.25 minutes, and the time to pass through the aging crystallization section is 7.5 minutes.

[0051] Along the moving direction of the film material, the aging crystallization section of the oven is divided into the first tension section, the second tension section and the third tension section according to its average length along its own length direction. The tension of the film material in the first tension section is 310N, the tension in the second tension section is 330N, and the tension in the third tension section is 350N.

[0052] After the film material comes out of the oven, it is rolled up at a tension of 360N, completing the aging and crystallization of the ITO film to obtain the ITO film.

[0053] Comparative Example 2

[0054] The rolled film material is unwound at a tension of 200N and then enters the drying oven. The speed of the film material in the drying oven is 4m / min.

[0055] Along the moving direction of the film material, the oven is divided into a preheating section and an aging crystallization section. The temperature of the preheating section is 100°C, and the temperature of the aging crystallization section is 160°C. The time for the film material to pass through the preheating section is 1.25 minutes, and the time to pass through the aging crystallization section is 7.5 minutes.

[0056] Along the moving direction of the film material, the aging crystallization section of the oven is divided into the first tension section, the second tension section and the third tension section according to its average length along its own length direction. The tension of the film material in the first tension section is 310N, the tension in the second tension section is 330N, and the tension in the third tension section is 350N.

[0057] After the film material comes out of the oven, it is rolled up at a tension of 360N, completing the aging and crystallization of the ITO film to obtain the ITO film.

[0058] Comparative Example 3

[0059] The rolled film material is unwound at a tension of 200N and then enters the drying oven. The speed of the film material in the drying oven is 5m / min.

[0060] Along the moving direction of the film material, the oven is divided into a preheating section and an aging crystallization section. The temperature of the preheating section is 100°C, and the temperature of the aging crystallization section is 155°C. The time for the film material to pass through the preheating section is 1 minute, and the time for passing through the aging crystallization section is 6 minutes.

[0061] Along the moving direction of the film material, the aging crystallization section of the oven is divided into the first tension section, the second tension section and the third tension section according to its average length along its own length direction. The tension of the film material in the first tension section is 310N, the tension in the second tension section is 330N, and the tension in the third tension section is 350N.

[0062] After the film material comes out of the oven, it is rolled up at a tension of 360N, completing the aging and crystallization of the ITO film to obtain the ITO film.

[0063] Comparative Example 4

[0064] The rolled film material is unwound at a tension of 200N and then enters the drying oven. The speed of the film material in the drying oven is 7m / min.

[0065] Along the moving direction of the film material, the oven is divided into a preheating section and an aging crystallization section. The temperature of the preheating section is 100°C, and the temperature of the aging crystallization section is 165°C. The time for the film material to pass through the preheating section is 0.7 min, and the time to pass through the aging crystallization section is 4.3 min.

[0066] Along the moving direction of the film material, the aging crystallization section of the oven is divided into the first tension section, the second tension section and the third tension section according to its average length along its own length direction. The tension of the film material in the first tension section is 310N, the tension in the second tension section is 330N, and the tension in the third tension section is 350N.

[0067] After the film material comes out of the oven, it is rolled up at a tension of 360N, completing the aging and crystallization of the ITO film to obtain the ITO film.

[0068] Comparative Example 5

[0069] The film material with the ITO layer coated is placed in an infrared furnace for aging. In the infrared furnace, the film material sample is directly placed on a conveyor belt for transportation. The aging temperature is 165°C, the speed is 4m / min, and the aging time is 7.5min.

[0070] Comparative Example 6

[0071] The film material with the ITO layer coated is placed in an infrared furnace for aging. In the infrared furnace, the film material sample is directly placed on a conveyor belt for transportation. The aging temperature is 160°C, the speed is 4m / min, and the aging time is 7.5min.

[0072] Comparative Example 7

[0073] The film material with the ITO layer coated is placed in an infrared furnace for aging. In the infrared furnace, the film material sample is directly placed on a conveyor belt for transportation. The aging temperature is 155°C, the speed is 5m / min, and the aging time is 6min.

[0074] Comparative Example 8

[0075] The film material with the ITO layer coated is placed in an infrared furnace for aging. In the infrared furnace, the film material sample is directly placed on a conveyor belt for transportation. The aging temperature is 155°C, the speed is 6m / min, and the aging time is 5min.

[0076] Comparative Example 9

[0077] The film material with the ITO layer coated is placed in an infrared furnace for aging. In the infrared furnace, the film material sample is directly placed on a conveyor belt for transportation. The aging temperature is 165°C, the speed is 7m / min, and the aging time is 4.3min.

[0078] Comparative Example 10

[0079] The difference between this comparative example and Example 1 lies in the running speed of the membrane material and the temperature of the aging crystallization stage. In this comparative example, the aging temperature is 120° C. and the running speed is 4 m / min.

[0080] Comparative Example 11

[0081] The difference between this comparative example and Example 1 lies in the travel speed of the membrane material and the temperature of the aging crystallization stage. In this comparative example, the aging temperature is 135° C. and the travel speed is 4 m / min.

[0082] Comparative Example 12

[0083] The difference between this comparative example and Example 1 lies in the running speed of the membrane material and the temperature of the aging crystallization stage. In this comparative example, the aging temperature is 150° C. and the running speed is 4 m / min.

[0084] Comparative Example 13

[0085] The difference between this comparative example and Example 1 lies in the running speed of the membrane material and the temperature of the aging crystallization stage. In this comparative example, the aging temperature is 165° C. and the running speed is 4 m / min.

[0086] Comparative Example 14

[0087] The difference between this comparative example and Example 1 lies in the running speed of the membrane material and the temperature of the aging crystallization stage. In this comparative example, the aging temperature is 160° C. and the running speed is 4 m / min.

[0088] Comparative Example 15

[0089] The difference between this comparative example and Example 1 lies in the running speed of the membrane material and the temperature of the aging crystallization stage. In this comparative example, the aging temperature is 155° C. and the running speed is 4 m / min.

[0090] Performance Testing

[0091] Test 1. After the aging of the film materials in Comparative Examples 5-9 is completed, the ITO film is cut into 3 pieces according to the width, each with a specification of 340*340mm. The sample is placed face up, and the upward height of the four corners is measured with a ruler. Then it is placed upside down and the downward height of the four corners is measured. The upward height is required to be ≤10mm and the downward height is ≤-3mm to be qualified.

[0092] Table 1 Infrared furnace aging results

[0093]

[0094] Note: The unit in Table 1 is mm.

[0095] It can be seen from the data in Table 1 that when the ITO film samples were transported by conveyor belt in the infrared furnace, the obtained film materials were warped and the results were all judged as NG, which did not meet the qualification requirements.

[0096] Test 2: After the films in comparative examples 10-15 come out of the oven, 12 points are taken on average along the width direction of the films, and the films are placed flat on the table with the film surface facing up. 12 points are taken on average along the width direction of the films, and the surface square resistance of the films is tested with a square resistance meter. The resistance value is required to be 105-145Ω for qualified crystallinity.

[0097] Table 2 Effect of oven aging crystallization stage temperature on crystallinity

[0098] Group Point 1 Point 2 Point 3 Point 4 Point 5 Point 6 Point 7 Point 8 Point 9 Point 10 Point 11 Point 12 average value Comparative Example 10 203 168 194 187 176 201 184 204 200 208 181 92 183 Comparative Example 11 189 177 168 193 187 184 184 204 180 184 172 184 184 Comparative Example 12 151 149 135 128 131 125 121 151 158 171 176 180 148 Comparative Example 13 119 120 120 122 122 119 119 118 117 123 119 126 120 Comparative Example 14 119 120 120 122 122 119 119 118 117 123 119 126 120 Comparative Example 15 120 121 121 122 121 117 118 118 118 118 119 121 119

[0099] Note: The unit in Table 2 is Ω.

[0100] It can be seen from Table 2 that the resistance values ​​of Comparative Examples 10-12 do not meet the requirements and the crystallinity is unqualified, while the resistance values ​​of Comparative Examples 13-15 all meet the requirements and the crystallinity is qualified, indicating that the temperatures of 155°C, 160°C and 165°C can all meet the crystallinity requirements.

[0101] Test 3. After the aging of the ITO films in Examples 1-2 and Comparative Examples 1-4 is completed, the ITO films are cut into 3 pieces according to the width, each with a specification of 340*340mm. The sample is placed face up, and the upward height of the four corners is measured with a ruler. Then, it is placed upside down and the downward height of the four corners is measured. The upward height is required to be ≤10mm and the downward height is ≤-3mm to be qualified.

[0102] Table 3 Warpage test results of each embodiment and each comparative example

[0103]

[0104]

[0105] Note: The unit in Table 3 is mm.

[0106] It can be seen from Table 3 that the running speed of the film in Comparative Examples 1-3 is relatively low, and the time for the film to pass through the aging and crystallization stage becomes longer, which makes the heat of the film higher, thus causing serious warping. Although the running speed of the film in Comparative Example 4 is relatively high, the temperature of the aging and crystallization stage is relatively high, which also causes serious warping of the film. The warping of the film in the embodiment of the present invention is relatively small, which meets the requirements.

[0107] In summary, in Test 1, a conveyor belt is used to transport the film material for aging and crystallization. During the transportation process, the film material has no tension or the tension is small, and the crystallization effect of the film material is not good, which causes the final product to have heavy warping and does not meet the qualified requirements. In the embodiment of the present invention, the film material passes through the oven with a certain tension, the crystallization effect is good, the warping is small, and the finished product meets the qualified requirements. At the same time, combined with Test 2 and Test 3, the present invention can control the aging crystallization temperature and the aging crystallization time, while ensuring the crystallization effect, better reduce the possibility of warping of the film material, so that the prepared film material meets the qualified requirements.

[0108] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0109] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An ITO film aging crystallization process, characterized in that: The steps include: Unwind the rolled film material at a certain tension; The unwound film is sent into an oven for heating and aging at a temperature of 155-160°C for 4-6 minutes. The film moves in the oven with a certain tension. After the film comes out of the oven, it is rolled up with a certain tension; Among them, the tension of the film material in the oven is greater than the unwinding tension, and less than the winding tension.

2. The ITO film aging crystallization process according to claim 1, characterized in that: The film is unwound at a tension of 200 to 220N.

3. The ITO film aging crystallization process according to claim 1, characterized in that: The tension of the film material in the oven is 250~350N.

4. The ITO film aging crystallization process according to claim 1, characterized in that: Along the moving direction of the film material, the tension of the film material increases step by step by 10 to 20N in the oven.

5. The ITO film aging crystallization process according to claim 1, characterized in that: Along the moving direction of the film material, the oven is divided into the first tension section, the second tension section and the third tension section. The film material tension in the first tension section is 250-310N, the film material tension in the second tension section is 260-330N, and the film material tension in the third tension section is 280-350N. Moreover, the tension of the film material in the first tension section is smaller than that in the second tension section, and the tension of the film material in the second tension section is smaller than that in the third tension section.

6. The ITO film aging crystallization process according to claim 1, characterized in that: The film material is preheated after entering the oven, and the preheating temperature is 100-120℃.

7. The ITO film aging crystallization process according to claim 6, characterized in that: The preheating time of the membrane material is 0.5 to 1 minute.

8. The ITO film aging crystallization process according to claim 1, characterized in that: The film is rolled up at a tension of 360 to 450N.

9. ITO film, characterized in that The invention is prepared by the ITO film aging crystallization process described in any one of claims 1 to 8.

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