Film, device and preparation method of device

Abstract

The invention provides a thin film and a preparation method and device thereof. The third film layer with proper thickness, refractive index n and extinction coefficient k is arranged on the second film layer, and the components of the second film layer and the third film layer are adjusted, so that the blue light reflected by the third film layer and the blue light reflected by the second film layer are subjected to destructive interference (destructive interference); meanwhile, the yellow light reflected by the third film layer and the yellow light reflected by the second film layer are subjected to constructive interference (constructive interference), so that the chromatic value b * of the thin film is changed from a negative value to a positive value, and the thin film has a warm color system effect.

Description

Technical Field

[0001] The present application relates to the field of film coating technology, and in particular to a thin film, a device and a method for preparing the device. Background Art

[0002] Silver film has a color similar to that of metal substrates such as stainless steel and is widely used. In current technology, the materials used to make silver film are mainly high-reflectivity elements such as aluminum (Al), silver (Ag) and chromium (Cr). Aluminum easily forms aluminum oxide on the surface, which reduces brightness, and is easily corroded by halogen ions and fails. Silver has limited application scenarios due to its high material cost. Chromium is widely used in silver film layers due to its advantages such as high corrosion resistance, high hardness and low surface energy.

[0003] In human eye perception, colors that tend to be warm (b>0) can make people feel excited, while colors that tend to be cold (b<0) can make people feel indifferent and peaceful. The brightness (L) of the silver film on the Cr substrate can reach 83, which is a cold material, and can make people think that the product is sharp and cold. Therefore, it is expected that the silver film on the surface of the product can be warm. Summary of the invention

[0004] In view of this, the present application proposes a film to achieve a warm color effect.

[0005] One embodiment of the present application provides a thin film formed on the surface of a substrate, the thin film comprising a first film layer, a second film layer and a second film layer stacked in sequence. The first film layer is located on the surface of the substrate. The second film layer is located on the surface of the first film layer away from the second film layer. The third film layer is located on the surface of the second film layer away from the first film layer. The second film layer includes chromium carbide. The third film layer includes chromium carbide, and the atomic percentage content of chromium in the third film layer is lower than the atomic percentage content of chromium in the second film layer. The thickness of the third film layer is 5nm to 20nm. When the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the second film layer is 1 to 3.8, and the extinction coefficient k of the second film layer is 1.8 to 4.3. When the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the third film layer is 1.2 to 3.3, and the extinction coefficient k of the third film layer is 1.8 to 4.3. The blue light reflected by the third film layer and the blue light reflected by the second film layer are superimposed to generate destructive interference, and the yellow light reflected by the third film layer and the yellow light reflected by the second film layer are superimposed to generate constructive interference.

[0006] In one embodiment, the thickness of the second film layer is 100 nm to 2000 nm.

[0007] In one embodiment, the film further comprises a transition layer, the transition layer is located between the first film layer and the second film layer, the thickness of the transition layer is 100nm to 2000nm, and the transition layer comprises chromium silicon nitride, titanium silicon nitride or tungsten silicon nitride.

[0008] In one embodiment, the thickness of the first film layer is 100 nm to 2000 nm, and the first film layer includes chromium, titanium or tungsten.

[0009] In one embodiment, the film has a thickness of 950 nm to 6000 nm.

[0010] In one embodiment, the substrate comprises a conductive material or a plastic. The conductive material comprises metal, silicon or carbon fiber, and the metal comprises stainless steel, aluminum, titanium, copper, nickel or magnesium. The plastic comprises one or more of polyvinyl chloride, polypropylene, polymethyl methacrylate, polystyrene, polyvinyl acetate, polyethylene terephthalate, styrene-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, polycarbonate, and polyamide.

[0011] One embodiment of the present application provides a device, which includes a substrate and the film as described above.

[0012] One embodiment of the present application provides a method for preparing a device, comprising the following steps: placing a substrate in a reaction furnace of a vacuum coating machine for cleaning; introducing argon gas into the reaction furnace, and turning on a power supply and a target material to deposit a first film layer on the surface of the substrate; introducing argon gas and a reaction gas into the reaction furnace, and turning on a power supply and a target material to deposit a second film layer on the surface of the first film layer, wherein the second film layer includes chromium carbide; introducing argon gas and a reaction gas into the reaction furnace, and turning on a power supply and a target material to deposit a third film layer on the surface of the second film layer to obtain the film. The third film layer includes chromium carbide, and the atomic percentage content of chromium in the third film layer is lower than the atomic percentage content of chromium in the second film layer, and the thickness of the third film layer is 10nm to 20nm. When the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the second film layer is 1 to 3.8, and the extinction coefficient k of the second film layer is 1.8 to 4.3. When the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the third film layer is 1.2 to 3.3, and the extinction coefficient k of the third film layer is 1.8 to 4.3. The blue light reflected by the third film layer and the blue light reflected by the second film layer are superimposed to produce destructive interference, and the yellow light reflected by the third film layer and the yellow light reflected by the second film layer are superimposed to produce constructive interference.

[0013] In one embodiment, in the step of depositing the first film layer, the flow rate of the argon gas is 150sccm to 500sccm, the target material includes a chromium target, a titanium target or a tungsten target, the working current of the power supply is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, and the duration is 54min to 66min. In the step of depositing the second film layer, the flow rate of the argon gas is 50sccm to 300sccm, the flow rate of the reaction gas is 5sccm to 35sccm, the reaction gas includes methane or acetylene, the target material includes a chromium target, and the number of chromium targets is W1; the working current of the power supply is I1, I1 is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, the duration is T1, and T1 is 22.5min to 27.5min. In the step of depositing the third film layer, the flow rate of the argon gas is 50 sccm to 300 sccm, the flow rate of the reaction gas is 5 sccm to 35 sccm, the reaction gas includes methane or acetylene, the target material includes a chromium target, and the number of the chromium targets is W2; the working current of the power supply is I2, I2 is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, the duration is T2, T2 is 3.15min to 3.85min. Wherein, W2<W1, I2<I1, T2<T1.

[0014] In one embodiment, before the step of "depositing a second film layer on the surface of the first film layer", the preparation method further includes: introducing argon and nitrogen into the reaction furnace, and turning on the power supply and the target material to deposit a transition layer on the surface of the first film layer. The flow rate of the argon gas is 150sccm to 500sccm, and the flow rate of the nitrogen gas is 25sccm to 80sccm. The target material includes a silicon target, and also includes a chromium target, a titanium target or a tungsten target. The working current of the power supply is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, and the duration is 81min to 99min.

[0015] The present application arranges a third film layer with a suitable thickness, refractive index n and extinction coefficient k on the second film layer, and adjusts the components of the second film layer and the third film layer so that the blue light reflected by the third film layer and the blue light reflected by the second film layer undergo destructive interference (destructive interference), and at the same time, the yellow light reflected by the third film layer and the yellow light reflected by the second film layer undergo constructive interference (constructive interference), thereby changing the chromaticity value b* of the film from a negative value to a positive value, thereby giving the film a warm color effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a device and a film according to one embodiment of the present application.

[0017] Figure 2 Schematic diagram of constructive interference caused by the superposition of two waves.

[0018] Figure 3 Schematic diagram of the destructive interference caused by the superposition of two waves.

[0019] Figure 4 This is a schematic diagram of the film prepared in Comparative Example 1 of the present application.

[0020] Figure 5 This is a color distribution diagram of the films prepared in Examples 1 to 3 of the present application.

[0021] Figure 6 This is a curve diagram of the refractive index n and extinction coefficient k of the surface layer of the film prepared in Example 1 of the present application.

[0022] Figure 7 This is a curve diagram of the refractive index n and extinction coefficient k of the surface layer of the film prepared in Comparative Example 1 of the present application.

[0023] Fig. 8A This is a scanning electron microscope (SEM) image of the film prepared in Example 1 of the present application.

[0024] Figure 8B This is a scanning electron microscope image of the cross section of the film prepared in Example 1 of the present application.

[0025] Fig. 9A This is a scanning electron microscope image of the film prepared in Example 2 of the present application.

[0026] Fig. 9B This is a scanning electron microscope image of the cross section of the film prepared in Example 2 of the present application.

[0027] Fig. 10A This is a scanning electron microscope image of the film prepared in Example 3 of the present application.

[0028] Fig. 10B This is a scanning electron microscope image of the cross section of the film prepared in Example 3 of the present application.

[0029] Main component symbols

[0030] 1000: device; 100: film; 200: substrate; 10: first film layer; 20: second film layer; 30: third film layer; 40: transition layer.

[0031] The following specific implementation manner will further illustrate the embodiments of the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0032] Unless otherwise defined, all technical and scientific terms used herein are identical with the meanings generally understood by those skilled in the art of the technical field belonging to the embodiments of the present application. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present application. In the embodiments, if specific conditions are not specified, they are carried out according to the conditions recommended by normal conditions or manufacturers. If the manufacturer is not specified for reagents or instruments, they are all conventional products that can be obtained by commercial purchase.

[0033] It will be understood that when a layer is referred to as being “on” another layer, it can be directly on the other layer or intervening layers may be present therebetween. In contrast, when a layer is referred to as being “directly on” another layer, there are no intervening layers present.

[0034] Here, the embodiments of the present application are described with reference to the cross-sectional views, which are schematic diagrams of the idealized embodiments (and intermediate configurations) of the present application. Thus, it is foreseeable that the shapes of the diagrams are different due to manufacturing processes and / or tolerances. Therefore, the embodiments of the present application should not be interpreted as being limited to the specific shapes of the regions illustrated here, but should include deviations in shapes such as those produced due to manufacturing. The regions shown in the figures are themselves only schematic, and their shapes are not intended to illustrate the actual shapes of the devices, and are not intended to limit the scope of the present application.

[0035] Some embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0036] See also Figure 1In a first aspect, the present application provides a thin film 100, which is formed on the surface of a substrate 200. The thin film 100 includes a first film layer 10, a second film layer 20, and a third film layer 30 which are stacked in sequence. The first film layer 10 is located on the surface of the substrate 200, the second film layer 20 is located on the surface of the first film layer 10 away from the second film layer 20, and the third film layer 30 is located on the surface of the second film layer 20 away from the first film layer 10. The first film layer 10 is used to connect the substrate 200 to increase the adhesion of the thin film 100 on the surface of the substrate 200, thereby reducing the probability of the thin film 100 falling off the surface of the substrate 200. The second film layer 20 and the third film layer 30 are used to reflect incident light so that the thin film 100 presents a certain color (for example, silver, etc.). The material of the second film layer 20 and the third film layer 30 is chromium carbide (CrC), which has a high refractive index n and a high extinction coefficient k, and has a high reflective property. Although the second film layer 20 and the third film layer 30 are both chromium carbide, the content of chromium in these two film layers is different, so the incident light will be reflected on the surface of both the third film layer 20 and the second film layer 20. In the present application, the atomic percentage content of chromium in the third film layer 30 is lower than the atomic percentage content of chromium in the second film layer 20. The second film layer 20 formed by chromium carbide has a high reflective property, and the film 100 as a whole presents a high brightness (large L*) effect; the third film layer 30 formed by chromium carbide can achieve the effect of increasing the reflection of yellow light (constructive interference) without affecting the color and brightness of the second film layer 20, so that the film 100 achieves a warm color effect.

[0037] The thickness of the third film layer 30 is 5nm to 15nm. For example, the thickness of the third film layer 30 can be 5nm, 6nm, 7nm, 8nm, 10nm, 11nm, 15nm or any value between any two adjacent values ​​mentioned above. When the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the third film layer 30 is 1.2 to 3.3, and the extinction coefficient k of the third film layer 30 is 1.8 to 4.3. Under the above conditions, the blue light reflected by the third film layer 30 and the blue light reflected by the second film layer 20 are superimposed to produce destructive interference, and the yellow light reflected by the third film layer 30 and the yellow light reflected by the second film layer 20 are superimposed to produce constructive interference. The reasons why the blue light undergoes destructive interference and the yellow light undergoes constructive interference will be explained in detail below.

[0038] like Figure 1 As shown, when incident light enters the film 100, the incident light will be reflected by the third film layer 30 and the second film layer 20 respectively, and the total reflected light is the sum of the reflected light of the third film layer 30 and the reflected light of the second film layer 20. Figure 2 As shown, if the peak (or trough) of the light reflected by the third film layer 30 is close to or consistent with the peak (or trough) of the light reflected by the second film layer 20, constructive interference (constructive interference) will occur. Figure 3As shown, if the peak (or trough) of the reflected light of the third film layer 30 is close to or consistent with the trough (or peak) of the reflected light of the second film layer 20, destructive interference (destructive interference) occurs. When the optical path difference 2nd = (i + 1 / 2) λ, the two groups of reflected light have constructive interference; when the optical path difference 2nd = iλ, the two groups of emitted light have destructive interference. Wherein, d is the thickness of the third film layer 30, and i and n are integers.

[0039] The inventors of the present application have discovered that the composition, optical parameters (refractive index n, extinction coefficient k) and thickness of the interference film layer (the third film layer 30 of the present application) will affect the chromaticity value (L*, a*, b*) of the film 100. Among them, L* represents brightness (black and white), and L* is 0 to 100, and there is no negative value. The larger the L*, the whiter (brighter), and the smaller the L*, the darker (darker). a* represents red and green, and there are positive and negative values. A positive a* represents reddish, and a negative a* represents greenish (not red enough). b* represents yellow and blue, and there are also positive and negative values. A positive b* represents yellowish, and a negative b* represents bluish. That is, if the blue light undergoes destructive interference and the yellow light undergoes constructive interference, the chromaticity value b* is a positive value, and the color of the film 100 will be warm. Therefore, the inventors of the present application adjusted the components of the second film layer 20 and the third film layer 30 (chromium carbide, and the atomic percentage content of chromium in the third film layer 30 is lower than the atomic percentage content of chromium in the second film layer 20), the thickness d of the third film layer 30, and the refractive index n and extinction coefficient k of the third film layer 30, so that the optical path difference between the blue light reflected by the third film layer 30 and the blue light reflected by the second film layer 20 is an integer multiple of the wavelength (2nd=iλ), and the blue light reflected by the third film layer 30 and the blue light reflected by the second film layer 20 undergo destructive interference (destructive interference), and at the same time, the optical path difference between the yellow light reflected by the third film layer 30 and the yellow light reflected by the second film layer 20 is an odd multiple of half the wavelength (2nd=(i+1 / 2)λ), and the yellow light undergoes constructive interference (constructive interference). Under the premise that the chromaticity values ​​L* and a* remain roughly unchanged, the chromaticity value b* is changed from a negative value to a positive value, thereby making the film 100 have a warm color effect.

[0040] In some embodiments, the third film layer 30 can be formed by physical vapor deposition (PVD) technology. Specifically, the third film layer 30 can be formed by medium frequency magnetron sputtering (MF). The third film layer 30 can use chromium as a target material, and a reactive gas (methane or acetylene) can be introduced during the sputtering process. The target material can be a cylindrical target or a planar target, which is not limited in the present application.

[0041] In some embodiments, when the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the second film layer 20 is 1 to 3.8, and the extinction coefficient k of the second film layer 20 is 1.8 to 4.3. The thickness of the second film layer 20 may be 100nm to 2000nm. In this way, it is ensured that the second film layer 20 can reflect the incident light. The thickness of the second film layer 20 may be 100nm, 500nm, 600nm, 700nm, 800nm, 1000nm, 2000nm, or any value between any two adjacent values ​​above.

[0042] In some embodiments, the second film layer 20 can be formed by medium frequency magnetron sputtering. The second film layer 20 can use chromium as a target material, and the target material can be a cylindrical target or a planar target. Reactive gas (methane or acetylene) needs to be introduced during the sputtering process.

[0043] In some embodiments, Figure 1 As shown, the film 100 further includes a transition layer 40, which is located between the first film layer 10 and the second film layer 20. The transition layer 40 can increase the bonding force between the second film layer 20 and the first film layer 10, and can further improve the adhesion of the film 100 on the surface of the substrate 200.

[0044] Further, the thickness of the transition layer 40 may be 100 nm to 2000 nm to ensure the bonding force between the second film layer 20 and the first film layer 10. The thickness of the transition layer 40 may be 100 nm, 500 nm, 510 nm, 540 nm, 600 nm, 650 nm, 700 nm, 1000 nm, 2000 nm or any value between any two adjacent values ​​thereof.

[0045] Further, the transition layer 40 may be chromium silicon nitride (CrSiN), titanium silicon nitride (TiSiN) or tungsten silicon nitride (WSiN), and the transition layer 40 may be formed by medium frequency magnetron sputtering. The transition layer 40 may use chromium and silicon as target materials, or use chromium silicon alloys in various proportions as target materials, and then introduce reaction gas (nitrogen) during the sputtering process to form a CrSiN transition layer 40. The transition layer 40 may use pure titanium and pure silicon as target materials, or use titanium silicon alloys in various proportions as target materials, and then introduce reaction gas (nitrogen) during the sputtering process to form a TiSiN transition layer 40. The transition layer 40 may use pure tungsten and pure silicon as target materials, or use tungsten silicon alloys in various proportions as target materials, and then introduce reaction gas (nitrogen) during the sputtering process to form a WSiN transition layer 40. The above-mentioned target materials may be cylindrical targets or planar targets, and the present application does not limit them.

[0046] In some embodiments, the material of the first film layer 10 may be, but is not limited to, chromium, titanium or tungsten. The first film layer 10 may be formed by medium frequency magnetron sputtering, and the target material may be a chromium target, a titanium target or a tungsten target. The thickness of the first film layer 10 may be 190nm to 400nm. For example, the thickness of the first film layer 10 may be 190nm, 195nm, 210nm, 270nm, 300nm, 350nm, 400nm or any value between any two adjacent values ​​mentioned above. The thickness of the first film layer 10 is within the above range, which can ensure the adhesion of the film 100 to the surface of the substrate 200, thereby reducing the probability of the film 100 falling off the surface of the substrate 200.

[0047] In some embodiments, the total thickness of the film 100 may be 950 nm to 6000 nm to ensure that the film 100 has a suitable thickness and is not easy to fall off, is not easy to be scratched to expose the substrate 200, and can also control costs and avoid wasting resources.

[0048] In some embodiments, the substrate 200 may be a conductive material or plastic. The conductive material may be, but is not limited to, metal, silicon or carbon fiber, and the metal may be, but is not limited to, stainless steel, aluminum, titanium, copper, nickel, magnesium, etc. The plastic may be one or more of polyvinyl chloride (PVC), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene (PS), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), styrene-acrylonitrile copolymer (SAN), ethylene-vinyl acetate copolymer (EVA), polycarbonate (PC), and polyamide (PA). The surface structure of the substrate 200 may be a polished surface, a brushed surface, or a sandblasted matte surface. If it is a polished surface, the chromaticity value L* of the film 100 may reach about 84 (L*~84).

[0049] Please continue reading Figure 1 In a second aspect, the present application provides a device 1000, which includes a substrate 200 and a film 100 formed on the surface of the substrate 200. The device 1000 can be a housing of an electronic product, or a container for packaging other products (e.g., cosmetics, toys, food, etc.), which is not limited by the present application. The electronic product can be a desktop computer, a laptop computer, a tablet computer, a mobile phone, a media player, a television, a wristwatch device, an earphone or receiver device, a head-mounted device, etc.

[0050] A third aspect of the present application provides a method for preparing a device 1000 , which includes steps S10 to S50 .

[0051] S10, placing the substrate 200 in a reaction furnace of a vacuum coating machine for cleaning.

[0052] In some embodiments, argon (Ar) gas may be introduced to perform plasma cleaning on the substrate 200. The flow rate of Ar may be 700 to 2000 sccm, the voltage (rotor bias) may be 500 to 1000 V, the duty cycle may be 50 to 90%, and the cleaning time may be 5 minutes to 30 minutes. For example, the flow rate of Ar may be 1000 sccm, the voltage (rotor bias) may be 600 V, the duty cycle may be 80%, and the cleaning time may be 20 minutes.

[0053] In some embodiments, the substrate 200 may be pretreated before being placed in the reaction furnace. The substrate 200 is cleaned with pure water, cleaning agents (weak acid and weak base), bubbling, ultrasonic vibration and other procedures, and then dried. After being placed on a fixture, it is placed in a vacuum coating machine for vacuuming. First, the air pressure in the reaction furnace can be pumped from atmospheric pressure to 20 Pa, and then the Roots pump is turned on to assist in pumping the air to 7 Pa. Then, three molecular pumps are turned on to pump air to a high vacuum state, and heating is turned on at the same time to raise the temperature in the furnace to 100 ° C, and the moisture and residual gas in the furnace are removed and pumped to 6.0x10 -3 Pa. Next, the temperature in the furnace is raised to 120°C and the gas is continuously pumped for 2 hours before the temperature is lowered back to 100°C. The pretreatment is completed. After the pretreatment is completed, the substrate 200 can be plasma cleaned.

[0054] S20 , introducing argon gas into the reaction furnace, and turning on the power supply and the target material to deposit the first film layer 10 on the surface of the substrate 200 .

[0055] In some embodiments, the flow rate of argon gas can be 150sccm to 500sccm. Turn on the power supply and target, the operating current can be 6A to 14A, the turret bias (voltage) can be 100V to 250V, the duty cycle can be 40% to 90%, and the duration can be 60±60×10%min, that is, 54min to 66min. For example, the Ar flow rate can be 300sccm, 2 pairs of chromium targets can be turned on, the operating current can be 8A, the turret bias can be 200V, the duty cycle can be 70%, and the duration can be 60min.

[0056] S30 , introducing argon and nitrogen into the reaction furnace, and turning on the power supply and the target material to deposit the transition layer 40 on the surface of the first film layer 10 .

[0057] In some embodiments, the flow rate of argon gas may be 150 sccm to 500 sccm, and the flow rate of nitrogen gas may be 25 sccm to 80 sccm. The target material may be a silicon target, and may also include a chromium target, a titanium target, or a tungsten target. The operating current is 6A to 14A, the turret bias (voltage) is 100V to 250V, the duty cycle is 40% to 90%, and the duration is 90±90×10%min, that is, 81min to 99min. For example, the flow rate of argon gas may be 300 sccm, and the flow rate of nitrogen gas may be 400 sccm. Turn on 1 pair of silicon targets and 2 pairs of chromium targets, the operating current may be 10A, the turret bias (voltage) may be 150V, the duty cycle may be 50%, and the duration may be 90min.

[0058] S40, introducing argon gas and reaction gas into the reaction furnace, and turning on the power supply and the target material to deposit the second film layer 20 on the surface of the transition layer 40 away from the first film layer 10. The second film layer 20 includes chromium carbide.

[0059] In some embodiments, the flow rate of argon gas may be 50 sccm to 300 sccm, the flow rate of the reaction gas may be 5 sccm to 35 sccm, and the reaction gas may be methane or acetylene. The target material may be a chromium target, and the number of chromium targets W1 may be adjusted according to actual needs. The operating current of the power supply is I1, and I1 may be 6A to 14A. The turret bias (voltage) of the power supply may be 100V to 250V, the duty cycle may be 40% to 90%, and the duration is T1, and T1 may be 25±25×10%min, that is, 22.5min to 27.5min. For example, the flow rate of argon gas may be 100 sccm, and the flow rate of acetylene may be 10 sccm. The number of opened chromium targets W1 may be 4 pairs, the operating current I1 of the power supply may be 10A, the turret bias (voltage) may be 200V, the duty cycle may be 50%, and the duration T1 may be 25min.

[0060] S50, introducing argon gas and reaction gas into the reaction furnace, and turning on the power supply and the target material to deposit the third film layer 30 on the surface of the second film layer 20 away from the transition layer 40, to obtain Figure 1 The thin film 100 is shown. The third film layer 30 includes chromium carbide.

[0061] In some embodiments, the flow rate of argon gas can be 50sccm to 300sccm, the flow rate of the reaction gas can be 5sccm to 35sccm, and the reaction gas can be methane or acetylene. The target material can be a chromium target, and the number of chromium targets W2 can be adjusted according to actual needs and must be less than W1. The working current of the power supply is I2, I2 is 6A to 14A, the turret bias (voltage) can be 100V to 250V, the duty cycle can be 40% to 90%, and the duration is T2, T2 can be 3.5±3.5×10%min, that is, 3.15min to 3.85min. Among them, W2<W1, I2<I1, T2<T1, so as to ensure that the atomic percentage content of chromium carbide element in the third film layer is lower than the atomic percentage content of chromium element in the second film layer. The voltage when depositing the third film layer can be equal to or less than the voltage when depositing the second film layer, and the duty cycle when depositing the third film layer can be equal to or less than the duty cycle when depositing the second film layer. For example, the flow rate of argon gas can be 100 sccm, the flow rate of acetylene can be 10 sccm, the number of turned-on chromium targets W2 can be 2 pairs, the working current I2 of the power supply can be 6A, the turret bias (voltage) can be 200V, the duty cycle can be 50%, and the duration T2 can be 3.5min.

[0062] The present application will be described in detail below with reference to specific embodiments and comparative examples.

[0063] Example 1

[0064] Pretreatment: The substrate (stainless steel, SUS 316) is cleaned with pure water, cleaning agents (weak acid and weak alkali), bubbling, ultrasonic vibration and other procedures, and then dried. It is placed on the fixture and placed in the vacuum coating machine for vacuuming. First, the air pressure in the reaction furnace can be pumped from atmospheric pressure to 20pa, and then the Roots pump is turned on to assist in pumping to make the air pressure in the furnace reach 7pa. Then, 3 molecular pumps are turned on to pump to a high vacuum state, and heating is started at the beginning to make the temperature in the furnace reach 100℃, remove the moisture and residual gas in the furnace, and pump to 6.0x10 -3 Pa. Next, the temperature in the furnace is raised to 120°C and the gas is continuously pumped for 2 hours before the temperature is lowered back to 100°C. The pretreatment is completed. After the pretreatment is completed, the substrate 200 can be plasma cleaned.

[0065] S10, placing the substrate in a reaction furnace of a vacuum coating machine for cleaning. The Ar flow rate is 1000 sccm, the voltage (rotor bias) is 600 V, the duty cycle is 80%, and the cleaning time is 20 minutes.

[0066] S20, depositing the first film layer. The argon gas flow rate is 300 sccm, two pairs of chromium targets are turned on, the working current is 8A, the turret bias is 200V, the duty cycle is 70%, and the duration is 60 minutes. The first film layer is a Cr layer.

[0067] S30, depositing a transition layer. The flow rate of argon is 300 sccm, and the flow rate of nitrogen is 40 sccm. One pair of silicon targets and two pairs of chromium targets are turned on, the operating current is 10A, the turret bias (voltage) is 150V, the duty cycle is 50%, and the duration is 90 minutes. The transition layer is CrSiN.

[0068] S40, deposit the second film layer. The flow rate of argon gas is 100 sccm, and the flow rate of acetylene is 10 sccm. Turn on 4 pairs of chromium targets, the working current of the power supply is 10A, the bias voltage (voltage) of the rotating frame is 200V, the duty cycle is 50%, and the duration is 25 minutes. The second film layer is CrC.

[0069] S50, depositing the third film layer. The flow rate of argon gas is 100 sccm, and the flow rate of acetylene is 10 sccm. Two pairs of chromium targets are turned on, the working current of the power supply is 6A, the bias voltage (voltage) of the rotating frame is 200V, the duty cycle is 50%, and the duration is 3.5min. The third film layer is CrC.

[0070] Example 2

[0071] The difference between Example 2 and Example 1 is that:

[0072] In S20, the argon gas flow rate is 500 sccm, the operating current is 6 A, the turret bias is 100 V, the duty cycle is 40%, and the duration is 66 min;

[0073] In S30, the flow rate of argon gas is 150 sccm, the flow rate of nitrogen gas is 80 sccm, the operating current is 6 A, the turret bias (voltage) is 200 V, the duty cycle is 40%, and the duration is 99 min;

[0074] In S40, the flow rate of argon gas is 50 sccm, the flow rate of acetylene is 5 sccm, the operating current is 14 A, the turret bias (voltage) is 250 V, the duty cycle is 40%, and the duration is 27.5 min;

[0075] In S50, the flow rate of argon gas is 50 sccm, the flow rate of acetylene can be 5 sccm, the operating current is 14 A, the turret bias (voltage) is 250 V, the duty cycle is 40%, and the duration is 3.15 min.

[0076] Example 3

[0077] The difference between Example 3 and Example 1 is that:

[0078] In S20, the argon gas flow rate is 150 sccm, the operating current is 14 A, the turret bias is 250 V, the duty cycle is 90%, and the duration is 54 min;

[0079] In S30, the flow rate of argon gas is 500 sccm, the flow rate of nitrogen gas is 25 sccm, the operating current is 14 A, the turret bias (voltage) is 250 V, the duty cycle is 90%, and the duration is 81 min;

[0080] In S40, the flow rate of argon gas is 300 sccm, the flow rate of acetylene is 35 sccm, the operating current is 6 A, the turret bias (voltage) is 100 V, the duty cycle is 90%, and the duration is 22.5 min;

[0081] In S50, the flow rate of argon gas is 300 sccm, the flow rate of acetylene can be 35 sccm, the operating current is 10 A, the turret bias (voltage) is 100 V, the duty cycle is 90%, and the duration is 3.85 min.

[0082] Comparative Example 1

[0083] The difference between Comparative Example 1 and Example 1 is that step S50 is omitted, and the following is obtained: Figure 4 The film shown. Figure 4 As shown, the film of Comparative Example 1 includes a first film layer 20 (the first film layer 20 is located on the surface of the substrate 200 ), a transition layer 40 , and a second film layer 20 arranged in sequence, and does not have a third film layer 30 .

[0084] The film 100 prepared in Examples 1 to 3 was tested for color distribution, and the following results were obtained: Figure 5 The color distribution diagram shown. In the reaction furnace of the vacuum coating machine, the furnace body contains a total of 10 layers of structures, namely, the upper, middle and lower layers. The substrate 200 can be placed on these 10 layers for coating. The substrate 200 may have color differences due to different sputtering angles of the target material.

[0085] Depend on Figure 5 It can be seen that in Examples 1 to 3 of the present application, the color distribution of the film 100 obtained from the substrate 200 of different layers in each embodiment is relatively consistent and uniform, indicating that the color distribution uniformity of the upper, middle and lower layers of the film 100 is relatively high during mass production of the preparation method of the present application.

[0086] The films of Example 1 and Comparative Example 1 were tested for chromaticity using a colorimeter (manufacturer: Konica Minolta, model: CM3700A). The test results of chromaticity are shown in Table 1.

[0087] Table 1

[0088] L* a* b* Example 1 84.07 -0.17 1.85 Comparative Example 1 84.83 -0.23 -1

[0089] As can be seen from Table 1, compared with the film in Comparative Example 1, the film in Example 1 of the present application has a warm color effect, while L* and a* remain roughly unchanged, and b* changes from a negative value to a positive value.

[0090] The thin films (surface layers) of Example 1 and Comparative Example 1 were tested for refractive index n and extinction coefficient k, respectively. See the test results. Figure 6 and Figure 7 .Depend on Figure 6 It can be seen that within the range of incident light wavelength of 250nm to 800nm, the refractive index n of the surface layer (third film layer) of the film of Example 1 is 1.2 to 3.3, and the extinction coefficient k is 1.8 to 4.3. Figure 7 It can be seen that within the range of incident light wavelength of 250nm to 800nm, the refractive index n of the surface layer (second film layer) of the film of Comparative Example 1 is 1 to 3.8, and the extinction coefficient k is 1.8 to 4.3.

[0091] An energy dispersive spectrometer (EDS) is used in conjunction with a scanning electron microscope (SEM) to perform elemental analysis on the films of Examples 1 to 3 and Comparative Example 1. EDS bombards the film surface with an electron beam (test conditions are 10 kV, penetrating to the second film layer), exciting the film to emit characteristic X-rays, and the composition of the film surface can be qualitatively and quantitatively analyzed based on the wavelength of the characteristic X-rays. The element types and contents (atomic percentage, indicating the percentage of the number of atoms of a certain element in the total number of atoms) of the second film layer in Comparative Example 1, as well as the element types and contents (atomic percentage, indicating the percentage of the number of atoms of a certain element in the total number of atoms) of the third film layer 30 and the second film layer 20 in Examples 1 to 3 are shown in Table 2 (others are trace components routinely added during the detection operation, such as oxygen atoms).

[0092] Table 2

[0093]

[0094]

[0095] In Comparative Example 1, the preparation steps of the second film layer are exactly the same as those of the second film layer in Example 1, so the composition of the second film layer in Example 1 is basically the same as that of the second film layer in Comparative Example 1. As shown in Table 2, the atomic percentage content (At%) of chromium in the third film layer and the second film layer of Example 1 is slightly lower than the atomic percentage content (At%) of the chromium primary color in Comparative Example 1, indicating that in the third film layer of Example 1, the atomic percentage content of chromium in the third film layer is lower than the atomic percentage content of chromium in the second film layer.

[0096] When the surface of the thin films of Examples 1 to 3 is analyzed by combining an energy dispersive spectrometer with a scanning electron microscope, the following results can be obtained: FIG. 8A to FIG. 10B Electron micrograph shown.

[0097] Depend on Fig. 8A It can be seen that in Example 1, the third film layer 30 is deposited more uniformly. Figure 8B It can be seen that the thickness of the first film layer 20 is 195 nm, the thickness of the transition film layer 40 is 568 nm, and the thickness of the second film layer 20 is 195 nm.

[0098] Depend on Fig. 9A It can be seen that in Example 2, the third film layer 30 is deposited more uniformly. Fig. 9B It can be seen that the thickness of the first film layer 20 is 195 nm, the thickness of the transition film layer 40 is 571 nm, and the thickness of the second film layer 20 is 179 nm.

[0099] Depend on Fig. 10A It can be seen that in Example 3, the third film layer 30 is deposited more uniformly. Fig. 10B It can be seen that the thickness of the first film layer 20 is 195 nm, the thickness of the transition film layer 40 is 574 nm, and the thickness of the second film layer 20 is 182 nm.

[0100] The film 100 of Examples 1 to 3 is subjected to chemical tests to test the corrosion resistance of the film 100 to various chemicals that are commonly encountered in life. The chemicals used for the test may be, but are not limited to: Banana Boat sunscreen, Ivory dishwashing liquid, Fantastik cleaning agent, yellow mustard, Coca-Cola, 70% isopropyl alcohol, extra virgin olive oil, vaseline, ketchup, mayonnaise, 409 cleaning agent, spray, acetone, artificial sweat, L'Oreal hairspray, Maybelline lipstick, Maybelline blush, sebum, hand sanitizer, black coffee, screen cleaner, Clorox disinfectant, oleic acid.

[0101] After applying the above chemicals evenly on the surface of the film, store it under refrigeration conditions or at a temperature of 65°C and a humidity of 90% for 72 hours, then wash the film, visually inspect it, observe whether there is any discoloration, corrosion, or film peeling on the surface of the film, and record the grade. Among them, grade A means there is no difference before and after the test; grade B means there is a small area of ​​discoloration after the test or the discoloration occurs only when water vapor is sprayed on the product; grade Ca means there is obvious visual discoloration after the test (maximum 55% grayscale), grade Cb means there is obvious visual discoloration after the test (maximum 70% grayscale), and grade Cc means there is obvious visual discoloration after the test (maximum 80% grayscale); grade D means the film layer is damaged, the surface texture is abnormal, but there are no corrosion points; grade F means the film is corroded and the film peels off.

[0102] After applying most of the above chemicals, the film of Examples 1 to 3 of the present application has a grade of B, that is, after the test, there is a small area of ​​discoloration or discoloration only occurs when water vapor is sprayed on the product; after applying Maybelline lipstick or Maybelline blush, there is no difference between the film before and after the test, and the grade is A; after applying a small part of the chemicals, the grade is Ca. It shows that the film of Examples 1 to 3 of the present application has good corrosion resistance and can fully meet the use needs in daily life.

[0103] The film 100 and the preparation method thereof of the embodiment of the present application are configured such that a third film layer 30 having a suitable thickness, a refractive index n and an extinction coefficient k is disposed on the second film layer 20, and the components of the second film layer 20 and the third film layer 30 are adjusted so that the blue light reflected by the third film layer 30 and the blue light reflected by the second film layer 20 undergo destructive interference (destructive interference), and the yellow light reflected by the third film layer 30 and the yellow light reflected by the second film layer 20 undergo constructive interference (constructive interference), thereby changing the chromaticity value b* of the film 100 from a negative value to a positive value, and thereby giving the film 100 a warm color effect.

[0104] The above descriptions are some specific implementations of the present application, but they are not limited to these implementations in actual application. For ordinary technicians in this field, other variations and changes made according to the technical concept of the present application should all fall within the protection scope of the present application.

Claims

1. A thin film formed on a surface of a substrate, characterized in that: The film comprises a first film layer, a second film layer, and a third film layer which are stacked in sequence. Wherein, the first film layer is located on the surface of the substrate, the second film layer includes chromium carbide, the third film layer includes chromium carbide, the atomic percentage content of chromium element in the third film layer is lower than the atomic percentage content of chromium element in the second film layer, and the thickness of the third film layer is 10nm to 20nm; when the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the second film layer is 1 to 3.8, and the extinction coefficient k of the second film layer is 1.8 to 4.3; when the incident light is in the wavelength range of 250nm to 800nm, the refractive index n of the third film layer is 1.2 to 3.3, and the extinction coefficient k of the third film layer is 1.8 to 4.3; the blue light reflected by the third film layer and the blue light reflected by the second film layer are superimposed to produce destructive interference, and the yellow light reflected by the third film layer and the yellow light reflected by the second film layer are superimposed to produce constructive interference.

2. The film according to claim 1, characterized in that The thickness of the second film layer is 100nm-2000nm.

3. The film according to claim 1, characterized in that The film further comprises a transition layer, which is located between the first film layer and the second film layer, has a thickness of 100 nm to 2000 nm, and comprises chromium silicon nitride, titanium silicon nitride or tungsten silicon nitride.

4. The film according to claim 1, characterized in that The thickness of the first film layer is 100 nm to 2000 nm, and the first film layer includes chromium, titanium or tungsten.

5. The film according to claim 1, characterized in that The thickness of the film is 950nm-6000nm.

6. The film according to claim 1, characterized in that The substrate is a conductive material or plastic, the conductive material includes metal, silicon or carbon fiber, the metal includes stainless steel, aluminum, titanium, copper, nickel or magnesium, and the plastic includes one or more of polyvinyl chloride, polypropylene, polymethyl methacrylate, polystyrene, polyvinyl acetate, polyethylene terephthalate, styrene-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, polycarbonate, and polyamide.

7. A device, characterized in that: The method comprises a substrate and the film according to any one of claims 1 to 6.

8. A method for preparing a device, characterized in that: The following steps are involved: The substrate is placed in a reaction furnace of a vacuum coating machine for cleaning; Introducing argon gas into the reaction furnace, and turning on a power source and a target material to deposit a first film layer on the surface of the substrate; Introducing argon gas and reaction gas into the reaction furnace, and turning on a power source and a target material to deposit a second film layer on the surface of the first film layer, wherein the second film layer includes chromium carbide; Introducing argon gas and reaction gas into the reaction furnace, and turning on the power supply and the target material to deposit a third film layer on the surface of the second film layer to obtain a thin film; Wherein, the third film layer includes chromium carbide, the atomic percentage content of chromium element in the third film layer is lower than the atomic percentage content of chromium element in the second film layer, and the thickness of the third film layer is 10nm~20nm; when the incident light is in the wavelength range of 250nm~800nm, the refractive index n of the second film layer is 1~3.8, and the extinction coefficient k of the second film layer is 1.8~4.3; when the incident light is in the wavelength range of 250nm~800nm, the refractive index n of the third film layer is 1.2~3.3, and the extinction coefficient k of the third film layer is 1.8~4.3; the blue light reflected by the third film layer and the blue light reflected by the second film layer are superimposed to produce destructive interference, and the yellow light reflected by the third film layer and the yellow light reflected by the second film layer are superimposed to produce constructive interference.

9. The preparation method according to claim 8, characterized in that: In the step of depositing the first film layer, the flow rate of the argon gas is 150 sccm to 500 sccm, the target material includes a chromium target, a titanium target or a tungsten target, the working current of the power supply is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, and the duration is 54min to 66min; In the step of depositing the second film layer, the flow rate of the argon gas is 50 sccm to 300 sccm; the flow rate of the reaction gas is 5 sccm to 35 sccm, and the reaction gas includes methane or acetylene; the target material includes a chromium target, and the number of the chromium targets is W1; the working current of the power supply is I1, I1 is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, and the duration is T1, T1 is 22.5min to 27.5min; In the step of depositing the third film layer, the flow rate of the argon gas is 50 sccm to 300 sccm; the flow rate of the reaction gas is 5 sccm to 35 sccm, and the reaction gas includes methane or acetylene; the target material includes a chromium target, and the number of the chromium targets is W2; the working current of the power supply is I2, I2 is 6A to 14A, the voltage is 100V to 250V, the duty cycle is 40% to 90%, the duration is T2, and T2 is 3.15min to 3.85min; Among them, W2<W1, I2<I1, T2<T1.

10. The preparation method according to claim 8, characterized in that: Before the step of "depositing a second film layer on the surface of the first film layer", the preparation method also includes: introducing argon and nitrogen into the reaction furnace, and turning on the power supply and the target material to deposit a transition layer on the surface of the first film layer; wherein the flow rate of the argon gas is 150sccm~500sccm, the flow rate of the nitrogen gas is 25sccm~80sccm, the target material includes a silicon target, and also includes a chromium target, a titanium target or a tungsten target, the operating current of the power supply is 6A~14A, the voltage is 100V~250V, the duty cycle is 40%~90%, and the duration is 81min~99min.

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