Silver nanowire heater and its preparation method and application

Abstract

The present invention relates to a silver nanowire heater, a preparation method thereof and an application. The preparation method of the nanowire heater comprises the following steps: preparing two contacts on a first substrate to obtain a pretreated first substrate; preparing a silver nanowire transparent conductive film on the surface of a second substrate, and preparing a positive electrode and a negative electrode on the surface of the silver nanowire transparent conductive film to obtain a pretreated second substrate; bonding the contact surface of the pretreated first substrate to the electrode surface of the pretreated second substrate by using an optical adhesive, and enabling the positive electrode and the negative electrode to be respectively combined with the two contacts and to be electrically connected to an external power source, so as to obtain a silver nanowire heater. The silver nanowire heater prepared by the preparation method has excellent compactness, can effectively block water vapor and oxygen, has high reliability, and can meet the use requirements of actual products.

Description

Technical Field

[0001] The present invention relates to the technical field of electric heating elements, and particularly to a silver nanowire heater, a preparation method thereof, and an application thereof. Background Art

[0002] Monitoring devices operate in outdoor open-air places. When applied in regions with extremely low outdoor temperatures such as northern China, northern Europe, and North America, due to large differences in environmental temperature, humidity, etc., the lenses of camera devices will fog or freeze, resulting in unclear images, affecting the monitoring effect, and even causing the camera to be unusable in severe cases. Traditional camera products mainly achieve the anti-fog function through methods such as hot fans, coating, and PDS heating. Among them, silver nanowires have a fast thermal response speed and are commonly used in the coating method to construct heaters.

[0003] Traditional silver nanowire heaters usually adopt a preparation process of layer-by-layer stacking deposition. However, the silver nanowire heaters prepared by layer-by-layer stacking deposition have poor compactness and low ability to block water vapor and oxygen. Even when a protective layer (overcoating, OC layer) is stacked and deposited on the surface of the silver nanowires, the silver nanowire heaters cannot meet the usage requirements of actual products in severe reliability tests. Summary of the Invention

[0004] Based on this, it is necessary to provide a silver nanowire heater, a preparation method thereof, and an application thereof for the above problems; the silver nanowire heater prepared by the preparation method has excellent compactness, can effectively block water vapor and oxygen, has high reliability, and can meet the usage requirements of actual products.

[0005] A preparation method of a silver nanowire heater includes the following steps:

[0006] Prepare two contacts on a first substrate to obtain a pretreated first substrate;

[0007] Prepare a silver nanowire transparent conductive film on the surface of a second substrate, and prepare a positive electrode and a negative electrode on the surface of the silver nanowire transparent conductive film to obtain a pretreated second substrate;

[0008] Adhere the contact surface of the pretreated first substrate to the electrode surface of the pretreated second substrate with an optical adhesive, so that the positive electrode and the negative electrode are respectively combined with the two contacts and can be electrically connected to an external power source to obtain a silver nanowire heater.

[0009] In one embodiment, at least two branches extend outward from one end of the positive electrode and the negative electrode away from the contacts, and the positive electrode and the negative electrode have an equal number of branches.

[0010] In one embodiment, the positive electrode and the negative electrode are each provided with two branches.

[0011] In one embodiment, the branches extend outward from the ends of the positive electrode or the negative electrode, and are provided with a wider outer end and a narrower inner end, and the inner end is connected to the end.

[0012] In one embodiment, the width of the inner end to the outer end of the branch increases.

[0013] In one embodiment, the width of the outer end of the branch is 2 mm - 3 mm more than the width of the inner end.

[0014] In one embodiment, the width of the inner end is 1 mm - 2 mm.

[0015] In one embodiment, the length from the inner end to the outer end of the branch is at least 40 mm.

[0016] A silver nanowire heater prepared by the preparation method of the silver nanowire heater as described above.

[0017] An application of the silver nanowire heater as described above in a camera window.

[0018] The preparation method of the silver nanowire heater according to the present invention is different from the traditional layer-by-layer stacking deposition preparation process. Through special flip-chip bonding and at the same time cooperating with the design of the lead-out electrodes, the structure of the silver nanowire heater is simplified, and the risks of structural looseness, easy water and oxygen permeability caused by layer-by-layer stacking deposition are reduced. And in the flip-chip bonding structure of the silver nanowire heater, on the one hand, the second substrate is used as a unique protective layer, which is beneficial to improving the ability of the silver nanowire heater to block water vapor and oxygen; on the other hand, it can ensure that the contact between layers is closer, thereby improving the density of the silver nanowire heater, which is beneficial to enhancing the reliability of the silver nanowire heater.

[0019] Therefore, the silver nanowire heater prepared by the preparation method has excellent density and strong water and oxygen barrier ability, high reliability, can meet the use requirements of actual products, and is especially suitable for camera windows in harsh outdoor environments such as low temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flowchart of the preparation method of the silver nanowire heater in one embodiment of the present invention;

[0021] Figure 2 It is a schematic structural diagram in one embodiment of the present invention where the positive electrode and the negative electrode are each provided with two branches.

[0022] Among them, 101 is the first substrate; 102 is the contact; 103 is the second substrate; 104 is the silver nanowire transparent conductive film; 105 is the electrode, 1051 is the end; 1052 is the branch, 1052a is the inner end, 1052b is the outer end; 106 is the optical adhesive. Detailed implementation manners

[0023] For the convenience of understanding the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, these embodiments or examples are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments or examples and are not intended to limit the present invention.

[0025] Combined with Figure 1 As shown, it is a flowchart of a preparation method of a silver nanowire heater provided by the present invention, including the following steps:

[0026] S1. Prepare two contacts 102 on the first substrate 101 to obtain a pre-treated first substrate;

[0027] S2. Prepare a silver nanowire transparent conductive film 104 on the surface of the second substrate 103, and prepare a positive electrode and a negative electrode on the surface of the silver nanowire transparent conductive film 104 to obtain a pre-treated second substrate;

[0028] S3. Use the optical adhesive 106 to bond the contact surface of the pre-treated first substrate to the electrode surface of the pre-treated second substrate, so that the positive electrode and the negative electrode are respectively combined with the two contacts 102 and can be electrically connected to an external power source to obtain a silver nanowire heater.

[0029] Among them, Figure 1 105 in represents the electrode. The present invention does not specifically specify the electrode 105, Figure 1 The electrode 105 in generally refers to the positive electrode and the negative electrode.

[0030] Different from the traditional preparation process of layer-by-layer stacking deposition, this preparation method simplifies the structure of the silver nanowire heater through special flip-chip bonding and simultaneously coordinates the design to lead out the electrode 105, reducing the risks of structural looseness, easy water and oxygen permeability caused by layer-by-layer stacking deposition. Moreover, in the flip-chip bonding structure of the silver nanowire heater, on the one hand, the second substrate 103 is used as a unique protective layer, which is beneficial to improving the ability of the silver nanowire heater to block water vapor and oxygen; on the other hand, it can ensure that the contact between layers is closer, thereby improving the compactness of the silver nanowire heater and being beneficial to enhancing the reliability of the silver nanowire heater.

[0031] In steps S1 and S2, the preparation method of respectively preparing the contact 102 and the electrode 105 on the first substrate 101 and the second substrate 103 is adopted. During the flip-chip bonding preparation process, the silver nanowire transparent conductive film 104 is directly encapsulated between the first substrate 101 and the second substrate 103. It can not only connect the contact 102 through an external wire to lead out the electrode 105 to ensure the conduction of the heater circuit, but also ensure that the silver nanowire transparent conductive film 104 and the electrode 105 are not eroded by water vapor and oxygen, and at the same time make the pre-treated first substrate and the pre-treated second substrate fit more closely, thereby improving the compactness of the silver nanowire heater.

[0032] Among them, based on the high conductivity of the electrode 105 and the contact 102, when the electrode 105 and the contact 102 are in contact and combined, using the contact 102 to connect an external wire and connect to an external power supply can achieve the conductive connection between the electrode 105 and the contact 102.

[0033] Specifically, the electrode 105 can be selected from a silver electrode or a silver-aluminum electrode; the contact 102 can be a pad. By welding the pad to an external wire and connecting the wire to an external power supply, the circuit conduction can be achieved.

[0034] When the contact 102 is a pad, the first substrate 101 is preferably a glass substrate, which can prevent the first substrate 101 from being damaged by high temperature during the preparation of the pad.

[0035] In an embodiment, one end of the positive electrode and the negative electrode far from the contact 102 both extend outwardly with a branch 1052, that is, both the positive electrode and the negative electrode are single-electrode structures.

[0036] In another embodiment, at least two branches 1052 extend outward from one end of the positive electrode and the negative electrode away from the contact point 102, and the positive electrode and the negative electrode have an equal number of branches 1052. For example, two branches 1052 extend outward from one end of the positive electrode and the negative electrode away from the contact point 102; or, three branches 1052 extend outward from one end of the positive electrode and the negative electrode away from the contact point 102; or, four branches 1052 extend outward from one end of the positive electrode and the negative electrode away from the contact point 102, etc.

[0037] By designing and improving the structure of the electrode 105, the present invention can reduce the current in a single electrode 105, thereby reducing the current density and Joule heat of the electrode 105, avoiding silver atom migration and thermal diffusion at the contact between the electrode 105 and the silver nanowire transparent conductive film 104, ensuring uniform distribution of the entire power line at the same time, avoiding overheating, significantly extending the power-on duration of the silver nanowire, and thus improving the reliability of the silver nanowire heater.

[0038] Preferably, when the positive electrode and the negative electrode are respectively provided with two branches, the reliability of the silver nanowire heater is better.

[0039] It should be noted that when a plurality of branches 1052 extend outward from one end of the positive electrode and the negative electrode away from the contact point 102, the structures between the respective branches 1052 in the positive electrode or the negative electrode are independent of each other and there is no fixed structural relationship. For example, when the end portion 1051 of the positive electrode or the negative electrode extends outward to form a plurality of branches 1052, the extending directions can be the same or different. Preferably, the end portion 1051 extends in the same direction to form a plurality of branches 1052, so that the plurality of branches 1052 are located on the same side of the end portion; the distances between the plurality of branches 1052 formed by extending the end portion 1051 of the positive electrode or the negative electrode can be the same or different. Preferably, the distances between the plurality of branches 1052 formed by extending from the same end portion are the same. The present invention does not make specific limitations in this regard.

[0040] The applicant has found through long-term and in-depth research that when the electrode 105 is relatively thin, the contact resistance between the electrode 105 and the silver nanowire transparent conductive film 104 will be too large, so that the current passes through the shortest path due to the water flow effect, and it is easy to cause the contact between the electrode 105 and the silver nanowire transparent conductive film 104 to fail; when the thickness of the electrode 105 is uniform, based on the fact that the overall resistance of the short path is small and the overall resistance of the long path is large, the power line distribution on the electrode 105 will be uneven, and the service life will be shortened due to the water flow effect, which will in turn affect the reliability of the silver nanowire heater.

[0041] Therefore, in order to effectively reduce the contact resistance between the electrode 105 and the silver nanowire transparent conductive film 104, as well as the overall resistance of the electrode 105, and further improve the reliability of the silver nanowire heater, preferably, the branch 1052 extends outward from the end 1051 of the positive electrode or the negative electrode, and has a wider outer end 1052b and a narrower inner end 1052a, and the inner end 1052a is connected to the end 1051.

[0042] It should be noted that the shape and size between the inner end 1052a and the outer end 1052b of the branch 1052 can be regular or irregular. For example, the width increases from the inner end 1052a to the outer end 1052b; or, the width from the inner end 1052a to the outer end 1052b is in a uniform wavy shape, etc.; the sizes of multiple branches 1052 of the positive electrode or the negative electrode can be the same or different, and preferably the sizes of multiple branches 1052 of the positive electrode or the negative electrode are the same. The present invention does not make specific limitations on this.

[0043] Preferably, the width of the branch 1052 increases from the inner end 1052a to the outer end 1052b, which can make the power line distribution uniform and is beneficial to further improving the reliability of the silver nanowire heater.

[0044] More preferably, the width of the outer end 1052b of the branch 1052 is 2 mm - 3 mm more than the width of the inner end 1052a, which is beneficial to further improving the uniformity of the power line distribution, thereby extending the service life of the silver nanowire heater.

[0045] Further preferably, as shown in Figure 2 When the positive electrode and the negative electrode each extend in the same direction and are provided with two branches 1052, the sizes of the branches 1052 of the positive electrode are equal, the sizes of the branches 1052 of the negative electrode are equal, and the width of the outer end 1052b of any branch is 2 mm - 3 mm more than the width of the inner end 1052a, the reliability of the silver nanowire heater is the best.

[0046] In one embodiment, the width of the inner end 1052a is 1 mm - 2 mm.

[0047] Preferably, the length of the branch 1052 from the inner end 1052a to the outer end 1052b is at least 40 mm, which can make the change rate of the width of the electrode 105 smaller and is beneficial to improving the stability of the electrode 105.

[0048] In one embodiment, the material of the second substrate 103 is preferably a flexible substrate, which is beneficial to further improving the protection effect of the second substrate 103 on the silver nanowire transparent conductive film 104 and the electrode 105, thereby further enhancing the ability of the silver nanowire heater to block water vapor and oxygen.

[0049] Specifically, the material of the second substrate 103 is selected from polyarylether nitrile (PEN) or polyethylene terephthalate (PET).

[0050] Preferably, the thickness of the second substrate 103 is 100 μm - 500 μm, more preferably 125 μm - 200 μm, which can enable the second substrate 103 to achieve the protective effect without affecting the transmittance of the silver nanowire heater.

[0051] In an embodiment, the positions of the two contacts 102 are designed to be close to each other, which can shorten the distance of the connecting wires. Correspondingly, the position of the electrode 105 needs to be adjusted to ensure that the electrode 105 can be combined with the contact 102 to achieve the conduction of the external power supply.

[0052] Specifically, the preparation process of the contact 102 and the electrode 105 can be selected from printing.

[0053] The deposition process of the silver nanowire transparent conductive film 104 is selected from spraying, spin coating, electrostatic adsorption or screen printing.

[0054] It should be noted that there is no fixed sequence for steps S1 and S2 in the present invention. Step S1 can be prepared first and then step S2, or step S2 can be prepared first and then step S1, or steps S1 and S2 can be prepared simultaneously. The present invention does not limit this, and those skilled in the art can choose according to the actual preparation requirements.

[0055] In step S3, the use of the optical adhesive 106 for auxiliary bonding helps to improve the bonding effect between the pretreated first substrate and the pretreated second substrate, and is beneficial to further improving the density of the silver nanowire heater.

[0056] Specifically, the positions of the contacts 102 and the electrode 105 can be reserved in the optical adhesive 106 to ensure the close contact between the contacts 102 and the electrode 105 and achieve efficient electron conduction.

[0057] Optionally, the optical adhesive 106 is selected from OCA optical adhesive.

[0058] In an embodiment, after bonding, defoaming treatment can be used to further remove the air remaining in the optical adhesive 106 during the flip-chip bonding process, making the contact between layers closer and further improving the reliability of the silver nanowire heater. Among them, the defoaming treatment method can be selected from pressure defoaming.

[0059] The present invention provides a silver nanowire heater prepared by the preparation method of the silver nanowire heater as described above.

[0060] The silver nanowire heater prepared by the preparation method described in the present invention has excellent compactness, can effectively block water vapor and oxygen, has high reliability, and can meet the usage requirements of actual products.

[0061] The present invention also provides an application of the silver nanowire heater as described above in a camera window.

[0062] The silver nanowire heater described in the present invention is used for a camera window, can achieve excellent defogging and defrosting effects, solve problems such as unclear captured images caused by fogging and frosting of the window, and ensure that the camera can be normally used in harsh working environments such as high temperature and high humidity.

[0063] Hereinafter, the silver nanowire heater, its preparation method and application will be further described through the following specific examples.

[0064] Example 1

[0065] Print and prepare two pads on a glass substrate to obtain a pretreated glass substrate.

[0066] Spin-coat a silver nanowire transparent conductive film on the surface of a PET substrate, and print and prepare a silver paste positive electrode and a silver paste negative electrode on the surface of the silver nanowire transparent conductive film to obtain a pretreated PET substrate. Among them, one end of the silver paste positive electrode and the silver paste negative electrode far from the pad extends outward with a uniformly thick and 1-mm-wide branch. The length from the inner end to the outer end of the silver paste positive electrode branch is 40 mm, and the length from the inner end to the outer end of the silver paste negative electrode branch is 40 mm.

[0067] After reserving the positions of the pads and the silver paste electrodes in the OCA optical adhesive, use the OCA optical adhesive to bond the pad surface of the pretreated first substrate to the electrode surface of the pretreated second substrate, and make the silver paste positive electrode and the silver paste negative electrode respectively combine with the two pads and be electrically connected to an external power supply, and perform pressure defoaming treatment to obtain a silver nanowire heater.

[0068] Perform a reliability test on the silver nanowire heater under the conditions of an environmental set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. It is measured that the working duration of the silver nanowire heater maintaining its heating performance unchanged is as high as 300 h.

[0069] Example 2

[0070] Print and prepare two pads on a glass substrate to obtain a pretreated glass substrate.

[0071] A silver nanowire transparent conductive film was screen-printed on the surface of a PEN substrate, and a silver paste positive electrode and a silver paste negative electrode were printed on the surface of the silver nanowire transparent conductive film to obtain a pretreated PEN substrate. Among them, one branch with a uniform thickness and a width of 2 mm extends outward from the end of the silver paste positive electrode and the silver paste negative electrode far from the pad. The length from the inner end to the outer end of the branch of the silver paste positive electrode is 45 mm, and the length from the inner end to the outer end of the branch of the silver paste negative electrode is 45 mm.

[0072] After reserving the positions of the pads and the silver paste electrodes in the OCA optical adhesive, the pad surface of the pretreated first substrate was bonded to the electrode surface of the pretreated second substrate by using the OCA optical adhesive, so that the silver paste positive electrode and the silver paste negative electrode were respectively combined with the two pads and could be electrically connected to an external power supply, and a pressure defoaming treatment was carried out to obtain a silver nanowire heater.

[0073] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. It was measured that the working duration of the silver nanowire heater maintaining its heating performance unchanged was as high as 338 h.

[0074] Comparative Example 1

[0075] A silver nanowire transparent conductive film was screen-printed on the surface of a glass substrate, and then a graphene protective layer was laminated on the surface of the silver nanowire transparent conductive film to obtain a silver nanowire heater.

[0076] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. It was measured that the working duration of the silver nanowire heater maintaining its heating performance unchanged was only 5 h.

[0077] Comparative Example 2

[0078] A silver nanowire transparent conductive film was screen-printed on the surface of a glass substrate, and then a polyvinyl alcohol protective layer was laminated on the surface of the silver nanowire transparent conductive film to obtain a silver nanowire heater.

[0079] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. It was measured that the working duration of the silver nanowire heater maintaining its heating performance unchanged was only 2 h.

[0080] Comparing Comparative Examples 1-2 and Examples 1-2, it can be seen that the silver nanowire heaters prepared in Examples 1-2 have high reliability. Under the environmental conditions of a temperature of 85°C and a humidity of 85%, they can work stably, and the working duration is as high as about 300 h. In contrast, Comparative Examples 1-2 adopt the traditional preparation process of layer-by-layer stacking deposition. Even with the addition of a graphene protective layer or a polyvinyl alcohol protective layer, the reliability of the prepared silver nanowire heaters is still poor. Under the environmental conditions of a temperature of 85°C and a humidity of 85%, the working duration is as low as about 2 h.

[0081] Therefore, the preparation method provided by the present invention can significantly improve the compactness of the silver nanowire heater, effectively block water vapor and oxygen, has high reliability, and can meet the use requirements of related products in harsh environments.

[0082] Example 3

[0083] The difference between Example 3 and Example 1 is that at the end of the silver paste positive electrode far from the pad, two branches with a uniform thickness and a width of 1 mm extend outward, and at the end of the silver paste negative electrode far from the pad, two branches with a uniform thickness and a width of 1 mm also extend outward. The lengths of the two branches of the silver paste positive electrode are both 40 mm, and the lengths of the two branches of the silver paste negative electrode are both 40 mm.

[0084] The silver nanowire heater was subjected to a reliability test under the conditions of an environmental set temperature of 85°C, a humidity of 85%, and an input voltage of 12V. The measured working duration of the silver nanowire heater to maintain its heating performance unchanged was as high as 447 h.

[0085] Example 4

[0086] The difference between Example 4 and Example 1 is that at the end of the silver paste positive electrode far from the pad, three branches with a uniform thickness and a width of 1 mm extend outward, and at the end of the silver paste negative electrode far from the pad, three branches with a uniform thickness and a width of 1 mm also extend outward. The lengths of the three branches of the silver paste positive electrode are both 40 mm, and the lengths of the three branches of the silver paste negative electrode are both 40 mm.

[0087] The silver nanowire heater was subjected to a reliability test under the conditions of an environmental set temperature of 85°C, a humidity of 85%, and an input voltage of 12V. The measured working duration of the silver nanowire heater to maintain its heating performance unchanged was 429 h.

[0088] Comparing Comparative Example 1, Example 3, and Example 4, it can be seen that when the ends of the positive electrode and the negative electrode far from the contact extend outwardly and are respectively provided with at least two branches, and the number of branches of the positive electrode and the negative electrode is equal, the reliability of the silver nanowire heater is improved; comparing Example 3 and Example 4, it can be seen that when the positive electrode and the negative electrode are respectively provided with two branches, the reliability of the silver nanowire heater is the best.

[0089] Example 5

[0090] The difference between Example 5 and Example 1 is that the width of the inner end to the outer end of the branches of the silver paste positive electrode and the silver paste negative electrode increases. The inner ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 1 mm, and the outer ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 0.5 mm wider than the inner ends.

[0091] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. The measured working duration for which the silver nanowire heater maintained its heating performance unchanged was 331 h.

[0092] Example 6

[0093] The difference between Example 6 and Example 3 is that the width of the inner end to the outer end of the branches of the silver paste positive electrode and the silver paste negative electrode increases. The inner ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 1 mm, and the outer ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 2 mm wider than the inner ends.

[0094] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. The measured working duration for which the silver nanowire heater maintained its heating performance unchanged was as high as 502 h.

[0095] Example 7

[0096] The difference between Example 7 and Example 3 is that the width of the inner end to the outer end of the branches of the silver paste positive electrode and the silver paste negative electrode increases. The inner ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 1 mm, and the outer ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 3 mm wider than the inner ends.

[0097] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. The measured working duration for which the silver nanowire heater maintained its heating performance unchanged was as high as 495 h.

[0098] Example 8

[0099] The difference between Example 8 and Example 3 is that the width of the silver paste positive electrode and the silver paste negative electrode increases from the inner end to the outer end of the branch. The inner ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 1 mm, and the outer ends of the branches of the silver paste positive electrode and the silver paste negative electrode are both about 5 mm wider than the inner ends.

[0100] The silver nanowire heater was subjected to a reliability test under the conditions of an ambient set temperature of 85 °C, a humidity of 85%, and an input voltage of 12 V. The working duration during which the silver nanowire heater maintained its heating performance unchanged was measured to be as high as 468 h.

[0101] Comparing Example 1, Example 3, and Examples 5-8, it can be seen that when the width of the branch increases from the inner end to the outer end, the reliability of the silver nanowire heater improves; comparing Example 3 and Examples 6-8, it can be seen that when the positive electrode and the negative electrode are each provided with two branches and the width of the branch increases from the inner end to the outer end, the reliability of the silver nanowire heater is better; comparing Examples 6-8, it can be seen that when the positive electrode and the negative electrode are each provided with two branches and the width of the outer end of the branch is 2 mm - 3 mm more than the width of the inner end, the reliability of the silver nanowire heater is the best.

[0102] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0103] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A preparation method of a silver nanowire heater, characterized in that, The preparation method of the silver nanowire heater comprises the following steps: Prepare two contacts on a first substrate to obtain a pretreated first substrate; Prepare a silver nanowire transparent conductive film on the surface of a second substrate, and prepare a positive electrode and a negative electrode on the surface of the silver nanowire transparent conductive film to obtain a pretreated second substrate; Bond the contact surface of the pretreated first substrate and the electrode surface of the pretreated second substrate with an optical adhesive, so that the positive electrode and the negative electrode are respectively combined with the two contacts and can be electrically connected to an external power supply to obtain a silver nanowire heater.

2. The preparation method of the silver nanowire heater according to claim 1, wherein, At least two branches extend outward from one end of the positive electrode and the negative electrode away from the contacts, and the positive electrode and the negative electrode have an equal number of branches.

3. The preparation method of the silver nanowire heater according to claim 2, wherein, The positive electrode and the negative electrode respectively have two branches.

4. The preparation method of the silver nanowire heater according to claim 2, wherein, The branches extend outward from the end of the positive electrode or the negative electrode, and have a wider outer end and a narrower inner end, and the inner end is connected to the end.

5. The preparation method of the silver nanowire heater according to claim 4, characterized in that, The width of the branches increases from the inner end to the outer end.

6. The preparation method of the silver nanowire heater according to claim 4, wherein The width of the outer end of the branches is 2 mm - 3 mm more than the width of the inner end.

7. The preparation method of the silver nanowire heater according to claim 4, characterized in that, The width of the inner end is 1 mm - 2 mm.

8. The preparation method of the silver nanowire heater according to claim 4, characterized in that, The length of the branches from the inner end to the outer end is at least 40 mm.

9. A silver nanowire heater prepared by the preparation method of the silver nanowire heater according to any one of claims 1 - 8.

10. An application of the silver nanowire heater according to claim 9 in a camera window.

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