High-conductivity corrosion-resistant film and preparation method thereof

Abstract

The invention discloses a high-conductivity corrosion-resistant film with wide color range, scratch resistance, corrosion resistance and good conductivity, the high-conductivity corrosion-resistant film comprises a conductive layer, a primary wear-resistant layer capable of displaying colors and a secondary wear-resistant layer which are sequentially stacked from bottom to top, the conductive layer is a Cr layer covering a substrate, the primary wear-resistant layer is formed by alternately stacking a plurality of CrxSiyCzNw layers with different refractive indexes, and the secondary wear-resistant layer is formed by alternately stacking a plurality of CrxSiyCzNw layers with different refractive indexes. The second-stage wear-resistant layer comprises at least one CrxNy layer, and when the number of the CrxNy layers is larger than 1, all the CrxNy layers are arranged in a stacked mode; wherein x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44. The invention also discloses a method for preparing the high-conductivity corrosion-resistant film.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film production and manufacturing, and particularly to a highly conductive and corrosion-resistant thin film and a preparation method thereof. Background Art

[0002] For smart watches with functions such as electrocardiogram (ECG) testing and blood oxygen detection, it is often necessary to provide a non-transparent PVD (Physical Vapor Deposition) conductive film on the back cover of the smart watch, so that the PVD conductive film can cooperate with the ECG (Electrocardiogram) component in the smart watch to detect various human body indicators (such as ECG and blood oxygen indicators). Therefore, the performance of the PVD conductive film directly determines the reliability of human body indicator detection and the presentation effect of the detection results. At present, the PVD conductive film in the industry bombards the target element onto the glass surface through magnetron sputtering coating to obtain a conductive film layer. Affected by the film layer structure and elements, traditional conductive films can either be corrosion-resistant and scratch-resistant, but their film layer conductivity is insufficient, or they will lose color change, scratch resistance, and corrosion resistance while meeting the conductivity requirements. It is difficult for the conductive film to simultaneously have wide color range control, scratch resistance, corrosion resistance, and high conductivity, and it is difficult to meet the diverse needs of different customers. Summary of the Invention

[0003] Based on this, in view of the above deficiencies, it is necessary to provide a highly conductive and corrosion-resistant thin film with a wide color range, scratch resistance, corrosion resistance, and good conductivity, as well as a preparation method thereof.

[0004] A highly conductive and corrosion-resistant thin film, which is used to adhere to the back cover of a smart wearable device and cooperate with an ECG component or / and a PPG sensor to detect human body indicators, includes a conductive layer, a first wear-resistant layer capable of displaying colors, and a second wear-resistant layer stacked in sequence from bottom to top. The conductive layer is a Cr layer covering a substrate. The first wear-resistant layer is formed by alternately stacking a plurality of Cr x Si y C z N w layers. The second wear-resistant layer includes at least one Cr x N y layer. When the number of Cr x N y layers is greater than 1, the Cr x N y layers are stacked. Wherein, x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44.

[0005] In one embodiment, the thickness of the conductive layer is 50 - 1000 nm, the thickness of the primary wear-resistant layer is 50 - 1000 nm, the thickness of the secondary wear-resistant layer is 50 - 1000 nm, and the resistance of the highly conductive and corrosion-resistant thin film is 1 - 10 Ω; the Lab color value coverage range of the highly conductive and corrosion-resistant thin film is: the L value is 38 - 75, the a value is 0 ± 20, and the b value is 0 ± 20; the Vickers hardness of the highly conductive and corrosion-resistant thin film is Hv 1200 - 1400.

[0006] In one embodiment, the conductive layer, the primary wear-resistant layer, and the secondary wear-resistant layer are stacked layer by layer on the substrate by magnetron sputtering coating.

[0007] The present invention also discloses a method for preparing the above-mentioned highly conductive and corrosion-resistant thin film, and the method includes the following steps:

[0008] S1. Calculate the sputtering power of each coating material according to the Lab color value of the target film layer;

[0009] S2. Select the coating material Cr as the target, use Ar gas as the auxiliary gas, and deposit Cr on the substrate according to the preset sputtering power to form a conductive layer;

[0010] S3. Select the coating materials Cr, Si, C, and N 2 gases as the targets, use Ar gas as the auxiliary gas, and deposit Cr, Si, C, and N on the conductive layer according to the preset sputtering power to form a primary wear-resistant layer formed by alternately stacking several Cr x Si y C z N w layers;

[0011] S4. Select the coating materials Cr and N 2 gases as the targets, use Ar gas as the auxiliary gas, and deposit Cr and N on the primary wear-resistant layer according to the preset sputtering power to form a secondary wear-resistant layer composed of at least one layer of Cr x N y layer, and obtain the highly conductive and corrosion-resistant thin film;

[0012] where x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44; the sputtering power includes the L value power, the a value power, and the b value power.

[0013] In one embodiment, in step S1, the sputtering power of Cr is calculated using the following formula:

[0014] PL Cr = sqrt[(L Cr - 48.43) / 1.583]^2;

[0015] Pa C r = sqrt[(a Cr - 0.264) / 0.00631]^2;

[0016] Pb Cr = sqrt[(b Cr + 0.7175) / 0.3869]^2;

[0017] Among them, PL Cr is the L - value power of Cr, and L Cr is the L - value of Cr in the target film layer; Pa Cr is the a - value power of Cr, and a Cr is the a - value of Cr in the target film layer; Pb Cr is the b - value power of Cr, and b Cr is the b - value of Cr in the target film layer.

[0018] In one of the embodiments, in step S1, the sputtering power of Si is calculated using the following formula:

[0019] PL Si = sqrt[(L - 52.42) / 0.6784]^2;

[0020] Pa Si = sqrt[(a - 0.6754) / 0.0154]^2;

[0021] Pb Si = sqrt[(b + 0.629) / 0.3022]^2;

[0022] Among them, PL Si is the L - value power of Si, and L Si is the L - value of Si in the target film layer; Pa Si is the a - value power of Si, and a Si is the a - value of Si in the target film layer; Pb Si is the b - value power of Si, and b Si is the b - value of Si in the target film layer.

[0023] In one of the embodiments, in step S1, the sputtering power of C is calculated using the following formula:

[0024] PL C = sqrt[(L - 63.02) / - 0.5369]^2;

[0025] Pa C = sqrt[(a - 3.889) / - 0.3084]^2;

[0026] PbC = sqrt[(b - 0.543) / 0.08673]^2;

[0027] Among them, PL C is the L - value power of C, and L C is the L - value of C in the target film layer; Pa C is the a - value power of C, and a C is the a - value of C in the target film layer; Pb C is the b - value power of C, and b C is the b - value of C in the target film layer.

[0028] In one of the embodiments, in step S1, the sputtering power of N is calculated using the following formula:

[0029] PL N = sqrt[(L - 58.87) / - 0.01602]^2;

[0030] Pa N = sqrt[(a - 1.593) / - 0.005528]^2;

[0031] Pb N = sqrt[(b - 2.623) / - 0.009291]^2;

[0032] Among them, PL N is the L - value power of N, and L N is the L - value of N in the target film layer; Pa N is the a - value power of N, and a N is the a - value of N in the target film layer; Pb N is the b - value power of N, and b N is the b - value of N in the target film layer.

[0033] In one of the embodiments, in step S3, by controlling the flow rate of N 2 gas, Cr x Si y C z N w layers with different refractive indices are deposited on the conductive layer.

[0034] In one of the embodiments, the Lab color value coverage range of the highly conductive and corrosion - resistant thin film is: the L - value is 38 - 75, the a - value is 0 ± 20, and the b - value is 0 ± 20; the Vickers hardness of the highly conductive and corrosion - resistant thin film is Hv1200 - 1400.

[0035] Implementing the highly conductive and corrosion - resistant thin film of the present invention and its preparation method, its surface layer has Cr x N yThe two - level wear - resistant layer composed of layers makes the Vickers hardness of the entire highly conductive and corrosion - resistant thin film reach Hv1200 - 1400, having good friction and scratch resistance. And the N element forms a protective film on the surface layer of the highly conductive and corrosion - resistant thin film, which can prevent the erosion of corrosive substances and extend the service life of the highly conductive and corrosion - resistant thin film; the setting of the Cr layer ensures the electrical conductivity of the highly conductive and corrosion - resistant thin film, so that the highly conductive and corrosion - resistant thin film can cooperate with ECG components or / and PPG sensors to detect human indicators; by setting the power of the coating materials, the atomic weights of the coating materials in the film layer can be changed, and then the color of the first - level wear - resistant layer can be changed, so that the color of the highly conductive and corrosion - resistant thin film can be adjusted as needed. Its Lab color value coverage range can reach L value of 38 - 75, a value of 0 ± 20, b value of 0 ± 20, obtaining thin films with diverse colors, which can meet the needs of users to a greater extent and make the product more aesthetically pleasing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of the highly conductive and corrosion - resistant thin film in an embodiment of the present invention;

[0037] Figure 2 It is a wavelength - reflectivity relationship diagram of the highly conductive and corrosion - resistant thin film in an embodiment of the present invention;

[0038] Figure 3 It is a flowchart of the preparation method of the highly conductive and corrosion - resistant thin film in an embodiment of the present invention;

[0039] Figure 4 It is a function diagram of the sputtering power of each coating material and the Lab value in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0041] Please refer to Figure 1 and Figure 2, the present invention discloses a highly conductive and corrosion-resistant film with a wide color range, scratch resistance, corrosion resistance, and good electrical conductivity. The highly conductive and corrosion-resistant film is used to adhere to the back cover of a smart wearable device and cooperate with an ECG component or / and a PPG sensor to detect human body indicators. In particular, the highly conductive and corrosion-resistant film is used as a non-transparent PVD conductive film for testing functions such as electrocardiogram and blood oxygen in a smart watch, and can also be used in the back covers of mobile phones, wearable devices, or smart devices such as computers, and can also act on different materials, such as ceramics, glass, sapphire, etc. The highly conductive and corrosion-resistant film is specifically used for importing the ECG (electrocardiogram) and PPG (postprandial plasma glucose) functions of a smart watch, and can also be used in the sensor field to sense conditions such as temperature, humidity, and gas.

[0042] Specifically, in this embodiment, the highly conductive and corrosion-resistant film includes a conductive layer 100, a first wear-resistant layer 200 capable of displaying colors, and a second wear-resistant layer 300 that are sequentially stacked from bottom to top. The conductive layer 100 is a Cr layer covering the substrate, and the Cr layer is used to ensure the electrical conductivity of the highly conductive and corrosion-resistant film so that the highly conductive and corrosion-resistant film can cooperate with an ECG component or / and a PPG sensor. The first wear-resistant layer 200 is formed by alternately stacking several Cr x Si y C z N w layers, and the second wear-resistant layer 300 includes at least one Cr x N y layer. When the number of Cr x N y layers is greater than 1, the Cr x N y layers are stacked; where x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44. In this solution, by controlling the number of each atom in the first wear-resistant layer 200 and the second wear-resistant layer 300, in particular, controlling the number of each atom in the first wear-resistant layer 200, a highly conductive and corrosion-resistant film with a preset color can be obtained to meet the user's requirements for the appearance and personalization of the film. In this embodiment, by setting a Cr x N y layer as the second wear-resistant layer 300 on the surface layer of the highly conductive and corrosion-resistant film, Cr x N yThe layer is a chromium nitride coating, which has high hardness, with a Vickers hardness as high as 1000 - 3000 Hv, and can significantly improve the wear resistance and service life of materials; it has excellent wear resistance and is suitable for machining high - requirement parts; due to the nitrogen element contained in the chromium nitride coating, a protective film can be formed on the surface to prevent the erosion of corrosive substances, thereby extending the service life of the equipment; in high - temperature or corrosive environments, a dense chromium oxide protective layer can be formed on the surface of the chromium nitride coating to enhance the oxidation - resistance and corrosion - resistance of the coating. Cr x N y The above properties of the layer are due to the fact that the chromium nitride adopts a cubic crystal system, has a unit cell in the shape of a cube, each unit cell contains one Cr and one N atom, and a strong covalent bond is formed between them. Such a crystal structure makes the chromium nitride have the advantages of high hardness, wear - resistance, and corrosion - resistance, thus improving the hardness, wear resistance, and corrosion resistance of the highly conductive and corrosion - resistant thin film. In addition, in this embodiment, since the highly conductive and corrosion - resistant thin film contains C and Cr, the thin film as a whole is opaque, which can effectively prevent the green light measured by the heart rate sensor from leaking out from areas other than the sensor, thereby affecting the heart rate test result and ensuring the reliability of the human body index detection result.

[0043] In one embodiment, the thickness of the conductive layer 100 is 50 - 1000 nm, the thickness of the primary wear - resistant layer 200 is 50 - 1000 nm, and the thickness of the secondary wear - resistant layer 300 is 50 - 1000 nm. That is to say, the overall thickness of the highly conductive and corrosion - resistant thin film ranges from 150 - 3000 nm. The conductive layer 100 is made of pure metal Cr with a thickness of 50 - 1000 nm, making the resistance of the highly conductive and corrosion - resistant thin film 1 - 10 Ω, ensuring the high - conductivity performance of the highly conductive and corrosion - resistant thin film. In this embodiment, by adjusting the atomic number of each element in the primary wear - resistant layer 200, a highly conductive and corrosion - resistant thin film with a preset color can be obtained. Preferably, the coverage range of the Lab color value of the highly conductive and corrosion - resistant thin film is: the L value is 38 - 75, the a value is 0 ± 20, and the b value is 0 ± 20. Set the secondary wear - resistant layer 300 composed of at least one layer of Cr x N y layer. The Vickers hardness of the highly conductive and corrosion - resistant thin film is Hv1200 - 1400.

[0044] In addition, in this embodiment, the conductive layer 100, the first wear-resistant layer 200, and the second wear-resistant layer 300 are stacked layer by layer on the substrate by magnetron sputtering coating. The substrate can be selected from one of sapphire, glass, ceramic, and plastic materials. The conductive layer 100, the first wear-resistant layer 200, and the second wear-resistant layer 300 are deposited by physical vapor deposition technology of magnetron sputtering coating, and its core technologies include target sputtering and ion-assisted deposition. Specifically, in the magnetron sputtering equipment, a solid material identical or similar to the thin film material to be deposited is selected as the target; in the vacuum chamber, the environment in the vacuum chamber is evacuated to reach a vacuum state through vacuum pumping; then, the surface of the target is activated by methods such as glow discharge or radio frequency radiation to ionize the working gas atoms or molecular ions to form a plasma. Next, a magnetic field is applied to the vacuum chamber to form a rotating plasma region called the "arc region"; in the arc region, the ions are controlled by the magnetic field and move along a spiral orbit, increasing the probability of hitting the surface of the target. The ion-assisted deposition process usually includes an ion source to generate a high-energy ion beam and guide it to the surface of the target, so that the atoms or molecules on the target are sputtered and deposited on the surface of the substrate at a high speed to form a thin film.

[0045] Please refer to Figures 1 - 4 , the present invention also discloses a method for preparing the above-mentioned highly conductive and corrosion-resistant thin film, and the method includes the following steps:

[0046] S1. Calculate the sputtering power of each coating material according to the Lab color value of the target film layer. The target film layer is the finally prepared highly conductive and corrosion-resistant thin film.

[0047] Specifically, in step S1, the sputtering power of Cr is calculated by the following formula:

[0048] PL Cr =sqrt[(L Cr -48.43) / 1.583]^2;

[0049] Pa C r=sqrt[(a Cr -0.264) / 0.00631]^2;

[0050] Pb Cr =sqrt[(b Cr +0.7175) / 0.3869]^2;

[0051] Among them, PL Cr is the L-value power of Cr, and its unit is Kw, L Cr is the L value of Cr in the target film layer; Pa Cr is the a-value power of Cr, and its unit is Kw, a Cr is the a value of Cr in the target film layer; Pb CrThe b-value power of Cr, with the unit of Kw, b Cr is the b-value of Cr in the target film layer.

[0052] In step S1, the sputtering power of Si is calculated using the following formula:

[0053] PL Si = sqrt[(L - 52.42) / 0.6784]^2;

[0054] Pa Si = sqrt[(a - 0.6754) / 0.0154]^2;

[0055] Pb Si = sqrt[(b + 0.629) / 0.3022]^2;

[0056] Among them, PL Si is the L-value power of Si, with the unit of Kw, L Si is the L-value of Si in the target film layer; Pa Si is the a-value power of Si, with the unit of Kw, a Si is the a-value of Si in the target film layer; Pb Si is the b-value power of Si, with the unit of Kw, b Si is the b-value of Si in the target film layer.

[0057] In step S1, the sputtering power of C is calculated using the following formula:

[0058] PL C = sqrt[(L - 63.02) / -0.5369]^2;

[0059] Pa C = sqrt[(a - 3.889) / -0.3084]^2;

[0060] Pb C = sqrt[(b - 0.543) / 0.08673]^2;

[0061] Among them, PL C is the L-value power of C, with the unit of Kw, L C is the L-value of C in the target film layer; Pa C is the a-value power of C, with the unit of Kw, a C is the a-value of C in the target film layer; Pb C is the b-value power of C, with the unit of Kw, b C is the b-value of C in the target film layer.

[0062] In step S1, the sputtering power of N is calculated using the following formula:

[0063] PL N = sqrt[(L - 58.87) / -0.01602]^2;

[0064] Pa N = sqrt[(a - 1.593) / -0.005528]^2;

[0065] Pb N = sqrt[(b - 2.623) / -0.009291]^2;

[0066] Wherein, PL N is the L - value power of N, with the unit of Kw, and L N is the L - value of N in the target film layer; Pa N is the a - value power of N, with the unit of Kw, and a N is the a - value of N in the target film layer; Pb N is the b - value power of N, with the unit of Kw, and b N is the b - value of N in the target film layer.

[0067] Thus, during the magnetron sputtering coating process, by controlling the power of the coating material during coating, the number of atoms in each layer of the finally formed thin film can be controlled to achieve the purpose of regulating the color of the thin film. In addition, in this step, according to the requirements of the user for parameters such as the color and refractive index of the first - level wear - resistant layer 200, the number of layers of Cr x Si y C z N w in the first - level wear - resistant layer 200 and the required Lab color values (i.e., the number of each atom) for each layer can be designed. At the same time, the number of layers of the second - level wear - resistant layer 300 and the required Lab color values (i.e., the number of each atom) for each layer can also be designed.

[0068] S2. Select the coating material Cr as the target, use Ar gas as the auxiliary gas, and deposit Cr on the substrate according to the preset sputtering power to form the conductive layer 100.

[0069] In this embodiment, before step S2, it also includes selecting and cleaning the substrate. The substrate is selected from one of sapphire, glass, ceramic, and plastic materials. Specifically, an appropriate cleaning solvent (such as detergent) is used to clean the surface of the substrate in an ultrasonic cleaner to remove grease, dust, and other contaminants on the surface of the substrate. Subsequently, the substrate is dried (using low - temperature drying or air - drying with a blower), and the appearance of the substrate is inspected for scratches, chipping, etc. The qualified substrate is fixed on the sample holder for standby.

[0070] Secondly, install the Cr target at the cathode position of the magnetron sputtering equipment, turn on the vacuum pump of the magnetron sputtering equipment, and evacuate the sputtering chamber to a vacuum state. Before depositing the Cr layer, the substrate can be further pretreated. Specifically, perform ion bombardment (ion cleaning) on the substrate to further clean the substrate surface and improve the film adhesion. Perform pre-sputtering on the Cr target for a period of time to remove oxides and other contaminants on the target surface.

[0071] Subsequently, fill the sputtering chamber with Ar gas, and adjust the Ar gas flow rate and pressure (generally between 0.1 - 1 Pa). Turn on the magnetron sputtering power supply and select an appropriate sputtering power. Preferably, in this embodiment, the sputtering power during the Cr layer deposition operation is 10 Kw. After reaching the set power and gas pressure, start the sputtering process. Cr atoms will be sputtered out and deposited on the substrate surface to form a thin film. By controlling the sputtering time or using a quartz crystal monitor, the film thickness can be precisely controlled. When the desired film thickness is reached, turn off the magnetron sputtering power supply. In this embodiment, the thickness of the Cr layer is 50 - 1000 nm.

[0072] S3. Select coating materials Cr, Si, C, and N 2 gases as targets, use Ar gas as the auxiliary gas, and deposit Cr, Si, C, and N on the conductive layer 100 according to the preset sputtering power to form a primary wear-resistant layer 200 composed of alternating stacks of several Cr x Si y C z N w layers.

[0073] In this embodiment, use N 2 gas as one of the targets for depositing the primary wear-resistant layer 200. It is the reaction gas during the Cr, Si, and C coating processes, so that the generated film layer contains N element. In step S3, by controlling the flow rate of N 2 gas, deposit Cr x Si y C z N w layers with different refractive indices on the conductive layer 100. In other words, in this embodiment, the refractive index of the interlayer in the primary wear-resistant layer 200 is determined by the flow rate of N 2 gas.

[0074] Specifically, install the Cr, Si, and C targets at the cathode position of the magnetron sputtering equipment, turn on the vacuum pump of the magnetron sputtering equipment, evacuate the sputtering chamber to a vacuum state, fill the sputtering chamber with Ar gas and N 2 gas, and adjust the flow rates and pressures of Ar gas and N 2 gas. Turn on the magnetron sputtering power supply and select an appropriate sputtering power. According to the Cr xSi y C z N w The number of layers and Lab values are used to adjust the sputtering power of each target in real time, so as to deposit Cr layers with different refractive indices that are stacked layer by layer on the conductive layer 100. x Si y C z N w layer. When the required film thickness is reached, the magnetron sputtering power supply is turned off. In this embodiment, the thickness of the first-level wear-resistant layer 200 is 50 - 1000 nm.

[0075] S4. Select Cr and N 2 gases as targets, use Ar gas as the auxiliary gas, and deposit Cr and N on the first-level wear-resistant layer 200 according to the preset sputtering power to form a second-level wear-resistant layer 300 composed of at least one layer of Cr x N y layers, thus obtaining a highly conductive and corrosion-resistant thin film. Among them, x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44; the sputtering power includes L-value power, a-value power, and b-value power.

[0076] Specifically, install the Cr target at the cathode position of the magnetron sputtering equipment, turn on the vacuum pump of the magnetron sputtering equipment, evacuate the sputtering chamber to a vacuum state, and fill the sputtering chamber with Ar gas and N 2 gas, and adjust the flow rate and pressure of Ar gas and N 2 gas. Turn on the magnetron sputtering power supply and select an appropriate sputtering power. According to the number of Cr x N y layers and Lab values designed in step S1, adjust the sputtering power of each target in real time, so as to deposit Cr x N y layers with different Lab values on the first-level wear-resistant layer 200. When the required film thickness is reached, turn off the magnetron sputtering power supply. In this embodiment, the thickness of the second-level wear-resistant layer 300 is 50 - 1000 nm.

[0077] In this embodiment, as the flow rate of N 2 gas increases, the phase of the Cr x N y layer experiences changes of Cr →... → Cr 2 N... → CrN. The nano-indentation hardness and elastic modulus of the film layer first increase and then decrease, the average friction coefficient and wear rate first decrease, then increase and then decrease, and the corrosion resistance first improves and then deteriorates. Therefore, by adjusting the flow rate of N 2 gas, the number of atoms of each element in the Cr x N y layer can be controlled, and thus the wear resistance and corrosion resistance of the second-level wear-resistant layer 300 can be controlled. When N2 When the gas flow rate is 30 cm 3 ·min-1, the coating structure is dense, and the mechanical properties, wear resistance, and corrosion resistance are optimal.

[0078] In an embodiment of the present invention, the power parameters for plating the conductive layer 100, the first-level wear-resistant layer 200, and the second-level wear-resistant layer 300 are shown in the following table:

[0079]

[0080]

[0081] It should be noted that in this embodiment, when plating the first-level wear-resistant layer 200 and the second-level wear-resistant layer 300, since the target material of the first-level wear-resistant layer 200 includes the target material of the second-level wear-resistant layer 300, therefore, after the plating of the first-level wear-resistant layer 200 is completed, there is no need to replace the target material, and only the coating power needs to be applied to the Cr and N 2 gas, and then the second-level wear-resistant layer 300 can be plated. A high-conductivity and corrosion-resistant thin film can be processed in one furnace, reducing the production cost of the high-conductivity and corrosion-resistant thin film.

[0082] After the high-conductivity and corrosion-resistant thin film is processed, the conductivity and performance of the thin film are tested. In this embodiment, before the product is delivered to the user, the color difference between the thin film and the user's product standard also needs to be tested. The color difference is calculated according to the following formula:

[0083] ΔEab = [(L1 - L2) 2 +(a1 - a2) 2 +(b1 - b2) 2 1 / 2 .

[0084] Among them, ΔEab is the actual color difference value, L1 is the L value of the standard Lab color value of the thin film required by the user, L2 is the L value of the Lab color value measured for the processed high-conductivity and corrosion-resistant thin film using a CM700D color difference meter; a1 is the a value of the standard Lab color value of the thin film required by the user, a2 is the a value of the Lab color value measured for the processed high-conductivity and corrosion-resistant thin film using a CM700D color difference meter; b1 is the b value of the standard Lab color value of the thin film required by the user, b2 is the b value of the Lab color value measured for the processed high-conductivity and corrosion-resistant thin film using a CM700D color difference meter.

[0085] ​When processing the highly conductive and corrosion-resistant thin film by the above method, the Lab color value coverage range of the highly conductive and corrosion-resistant thin film is: the L value is 38 - 75, the a value is 0 ± 20, and the b value is 0 ± 20. It has a wide color coverage range. By adjusting different Lab values, diverse colors can be obtained, which can meet the needs of customers to a greater extent and make the product more aesthetically pleasing. The Vickers hardness of the highly conductive and corrosion-resistant thin film is Hv1200 - 1400, which is about twice that of glass. It has good friction and scratch resistance. Verification such as 3000 times of rubber friction, pencil hardness, and 6000 times of sweat friction found that there are no obvious scratches on the conductive film and the conductive performance remains the same as before the test. In addition, it has been verified that it can still maintain the original color and conductive effect after being soaked in HClO solution / NaOH solution (soaking for more than 36 hours), and daily contact with chemicals will not affect the performance and appearance of this conductive film.

[0086] Implementing the highly conductive and corrosion-resistant thin film and its preparation method of the present invention, its surface layer has a secondary wear-resistant layer 300 composed of a Cr x N y layer, which makes the Vickers hardness of the entire highly conductive and corrosion-resistant thin film reach Hv1200 - 1400, has good friction and scratch resistance, and the N element forms a protective film on the surface layer of the highly conductive and corrosion-resistant thin film, which can prevent the erosion of corrosive substances and extend the service life of the highly conductive and corrosion-resistant thin film; the setting of the Cr layer ensures the conductive performance of the highly conductive and corrosion-resistant thin film, so that the highly conductive and corrosion-resistant thin film can cooperate with ECG components or / and PPG sensors to detect human indicators; by setting the power of the coating materials, the atomic weights of the coating materials in the film layer can be changed, and then the color of the primary wear-resistant layer 200 can be changed, so that the color of the highly conductive and corrosion-resistant thin film can be adjusted as needed. Its Lab color value coverage range can reach L value of 38 - 75, a value of 0 ± 20, and b value of 0 ± 20, obtaining a thin film with diverse colors, which can meet the needs of users to a greater extent and make the product more aesthetically pleasing.

[0087] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0088] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting 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 deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A highly conductive and corrosion-resistant film, used to be attached to the back cover of a smart wearable device and cooperate with an ECG element or / and a PPG sensor to detect human body indicators, characterized in that: The conductive layer, the primary wear-resistant layer capable of displaying colors, and the secondary wear-resistant layer are stacked in sequence from bottom to top. The conductive layer is a Cr layer covering the substrate. The primary wear-resistant layer is composed of a plurality of Cr layers with different refractive indices. x Si y C z N w The secondary wear-resistant layer includes at least one layer of Cr x N y layer, when Cr x N y When the number of layers is greater than 1, each Cr x N y Layer stacking arrangement; wherein x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44.

2. The highly conductive corrosion-resistant film according to claim 1, characterized in that: The thickness of the conductive layer is 50-1000nm, the thickness of the primary wear-resistant layer is 50-1000nm, the thickness of the secondary wear-resistant layer is 50-1000nm, and the resistance of the highly conductive corrosion-resistant film is 1-10Ω; the Lab color value coverage range of the highly conductive corrosion-resistant film is: L value is 38-75, a value is 0±20, and b value is 0±20; the Vickers hardness of the highly conductive corrosion-resistant film is Hv1200-1400.

3. The highly conductive corrosion-resistant film according to claim 1, characterized in that: The conductive layer, the primary wear-resistant layer and the secondary wear-resistant layer are deposited layer by layer on the substrate by magnetron sputtering coating.

4. A method for preparing the highly conductive and corrosion-resistant film according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Calculate the sputtering power of each coating material according to the Lab color value of the target film layer; S2, selecting the coating material Cr as the target material, using Ar gas as the auxiliary gas, and coating Cr on the substrate according to the preset sputtering power to form a conductive layer; S3, select coating materials Cr, Si, C and N2 gas as target materials, use Ar gas as auxiliary gas, and plate Cr, Si, C, N on the conductive layer according to the preset sputtering power to form a plurality of Cr with different refractive indices. x Si y C z N w The primary wear-resistant layer is formed by alternately stacking layers; S4, select the coating material Cr and N2 gas as the target material, use Ar gas as the auxiliary gas, and plate Cr and N on the primary wear-resistant layer according to the preset sputtering power to form at least one layer of Cr x N y A secondary wear-resistant layer composed of layers is produced to obtain a highly conductive and corrosion-resistant film; Among them, x is an integer not exceeding 33, y is an integer not exceeding 22, z is an integer not exceeding 44, and w is an integer not exceeding 44; the sputtering power includes L value power, a value power, and b value power.

5. The method according to claim 4, characterized in that In step S1, the sputtering power of Cr is calculated using the following formula: <h2 style=";text-align:left;direction:ltr">PL<h2 style=";text-align:left;direction:ltr"> Cr <h2 style=";text-align:left;direction:ltr"> =sqrt[(L<h2 style=";text-align:left;direction:ltr"> Cr <h2 style=";text-align:left;direction:ltr"> -48.43) / 1.583]^2; Pa C r=sqrt[(a Cr -0.264) / 0.00631]^2; Pb Cr =sqrt[(b Cr +0.7175) / 0.3869]^2; Among them, PL Cr is the L value power of Cr, L Cr is the L value of Cr in the target film; Pa Cr is the a value power of Cr, a Cr is the a value of Cr in the target film; Pb Cr is the b-value power of Cr, b Cr is the b value of Cr in the target film layer.

6. The method according to claim 4, characterized in that In step S1, the sputtering power of Si is calculated using the following formula: <h2 style=";text-align:left;direction:ltr">PL<h2 style=";text-align:left;direction:ltr"> Si <h2 style=";text-align:left;direction:ltr"> = sqrt[(L-52.42) / 0.6784]^2 Pa Si =sqrt[(a-0.6754) / 0.0154]^2; Pb Si =sqrt[(b+0.629) / 0.3022]^2; Among them, PL Si is the L value power of Si, L Si is the L value of Si in the target film; Pa Si is the a-value power of Si, a Si is the a value of Si in the target film; Pb Si is the b-value power of Si, b Si is the b value of Si in the target film layer.

7. The method according to claim 4, characterized in that In step S1, the sputtering power of C is calculated using the following formula: <h2 style=";text-align:left;direction:ltr">PL<h2 style=";text-align:left;direction:ltr"> C <h2 style=";text-align:left;direction:ltr"> =sqrt[(L-63.02) / -0.5369]^2; Pa C =sqrt[(a-3.889) / -0.3084]^2; Pb C =sqrt[(b-0.543) / 0.08673]^2; Among them, PL C is the L value power of C, L C is the L value of C in the target film layer; Pa C is the a value power of C, a C is the a value of C in the target film layer; Pb C is the b-value power of C, b C is the b value of C in the target film layer.

8. The method according to claim 4, characterized in that In step S1, the sputtering power of N is calculated using the following formula: <h2 style=";text-align:left;direction:ltr">PL<h2 style=";text-align:left;direction:ltr"> N <h2 style=";text-align:left;direction:ltr"> =sqrt[(L-58.87) / -0.01602]^2; Pa N =sqrt[(a-1.593) / -0.005528]^2; Pb N =sqrt[(b-2.623) / -0.009291]^2; Among them, PL N is the L value power of N, L N is the L value of N in the target film layer; Pa N is the power of N at value a, a N is the a value of N in the target film layer; Pb N is the b-value power of N, b N is the b value of N in the target film layer.

9. The method according to claim 4, characterized in that In step S3, by controlling the flow rate of N2 gas, Cr with different refractive indices is plated on the conductive layer. x Si y C z N w layer.

10. The method according to claim 4, characterized in that The Lab color value coverage range of the highly conductive corrosion-resistant film is: L value is 38-75, a value is 0±20, and b value is 0±20; the Vickers hardness of the highly conductive corrosion-resistant film is Hv1200-1400.

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