CN216816991U

CN216816991U - Improved high-reflection mirror coating

Info

Publication number: CN216816991U
Application number: CN202220479593.4U
Authority: CN
Inventors: 马丁·森斯; 眭凌杰; 孙伟明; 吴景权; 张燕华
Original assignee: Fujian Xinyue Metal Material Technology Co ltd
Current assignee: Fujian Xinyue Metal Material Technology Co ltd
Priority date: 2022-03-07
Filing date: 2022-03-07
Publication date: 2022-06-24
Anticipated expiration: 2032-03-07

Abstract

The utility model relates to an improved high-reflection mirror coating, which comprises a high-refractive-index layer, a low-refractive-index layer, an auxiliary layer and at least one composite layer which are sequentially arranged, wherein the auxiliary layer is used for diffusion barrier and adhesion promotion of a high-reflection metal material. The high-reflection mirror coating is coated on the coating surface of the metal substrate. The composite layer is located between the auxiliary layer and the metal substrate. The composite layer comprises a silver coating, an ultrathin coating, a middle layer and an aluminum coating which are sequentially arranged, wherein the middle layer is made of zinc oxide or metal-doped zinc oxide, and the ultrathin coating is made of chromium, chromium alloy, nickel alloy and/or nickel-chromium alloy. When the composite layers are provided in at least two, the composite layers are arranged one on top of another. Through the structure, the high-reflection mirror coating is more economical in cost, has the highest reflectivity, and is stable under the high-temperature condition of 180 ℃ or even higher and stable in a humid environment.

Description

Improved high-reflection mirror coating

Technical Field

The utility model relates to the field of light reflection coatings, in particular to an improved high-reflection mirror coating.

Background

Highly reflective mirror coatings, especially those with very high reflectivity in the wavelength range of 400nm to 2500nm, are widely used in lighting engineering, in equipment applications (e.g. flash lamps, projectors, solar energy collection and decoration applications), and the requirements of the emerging market are applications in the field of Concentrated Solar Power (CSP) and as back reflectors for LEDs in MC-COB modules.

The widely used way of the existing high-reflection mirror coating is to plate a high-reflectivity metal coating (such as aluminum or silver; wherein the reflectivity of silver is the highest of all metals in the wavelength range of interest) on a metal substrate, and then to match a low-refractive index layer, a high-refractive index layer, etc. However, the high-reflectivity mirror coating of the structure, especially the structure using silver as the high-reflectivity metal, is difficult to control the product cost and the high-temperature resistance and corrosion resistance (such as humid environment) of the high-reflectivity mirror coating. A coating system with high durability and method of making it, as disclosed in patent US6078425,2000, with a thin nickel chromium nitride ((NiCr) under the silver film layer_x）N_y) Layers, making the overall high temperature stability only general, especially if a sufficiently smooth substrate surface without any defects is not achieved, as is expected, for example, in large area coating systems for mass production; in the improved solution disclosed in patent US20060141272,2006, galvanic corrosion between the silver film and the aluminum substrate caused by pinhole defects is avoided by the thick tungsten (W) film, but information about its stability in high temperature applications is still missing and from a cost perspective, an additional tungsten layerGreatly increasing the cost of the coating. Further, as disclosed in patent CN101379218B, the vacuum coating scheme is also only suitable for use in good environmental conditions, and has poor durability in high temperature (e.g. up to 180 ℃ or even 200 ℃) and more severe (e.g. humid) environments.

In order to remain stable under high temperature conditions, both patents CN106796312B and CN108351442B propose to provide and implement a diffusion barrier between the substrate and the adhesion layer under the silver film layer. The proposed diffusion barrier layer functions to provide additional intermetallic diffusion inhibition between the aluminum-based substrate and the silver film layer. However, they all require a low productivity or a high investment cost of the coating tool from the viewpoint of the coated product estimated from the information disclosed in the patent document. The applicant has considered in patent application CN110908027A a feasible method of reducing operating costs and guaranteeing productivity. However, further cost reduction and material are desired directions, and lower cost may improve market positioning of the product.

SUMMERY OF THE UTILITY MODEL

The present invention provides an improved high reflection mirror coating to solve the above problems.

The utility model adopts the following technical scheme:

an improved high-reflectivity mirror coating comprises a high-refractive index layer, a low-refractive index layer, an auxiliary layer and at least one composite layer which are sequentially arranged, wherein the auxiliary layer is used for diffusion blocking and adhesion promotion of a high-reflectivity metal material. The high-reflection mirror coating is coated on the coating surface of the metal substrate. The composite layer is located between the auxiliary layer and the metal substrate. The composite layer comprises a silver coating, an ultrathin coating, a middle layer and an aluminum coating which are sequentially arranged, wherein the middle layer is made of zinc oxide or metal-doped zinc oxide, and the ultrathin coating is made of chromium, chromium alloy, nickel alloy and/or nickel-chromium alloy. When the composite layers are provided in at least two, the composite layers are arranged one on another.

Further:

the silver coating is formed by magnetron sputtering deposition. When one composite layer is arranged, the thickness of the silver coating is less than or equal to 50 nm. When the composite layer is provided with at least two, the thickness of the silver coating is < 40 nm.

The aluminum coating is formed by magnetron sputtering deposition. When one composite layer is arranged, the thickness of the aluminum coating is less than or equal to 50 nm. When the composite layers are provided in at least two, the thickness of the aluminum coating is < 50 nm.

The intermediate layer is made of aluminum-doped zinc oxide.

The intermediate layer is formed by magnetron sputtering deposition, and the thickness of the intermediate layer is 3nm-30 nm. The thickness of the ultrathin coating is 1nm-5 nm.

The thickness of the ultrathin coating is 2.5 nm.

Further:

the metal substrate is provided with a surface treatment layer on the film coating surface, the composite layer is covered on the surface treatment layer, the auxiliary layer is covered on the composite layer, the low refractive index layer is covered on the auxiliary layer, and the high refractive index layer is covered on the low refractive index layer. The surface treatment layer is an anodic oxidation layer, a varnish coating layer or a highly polished layer.

The metal substrate is made of aluminum or aluminum alloy, and the surface treatment layer is an anodic aluminum oxide thin film layer. The metal base material is a metal strip coiled material or a metal sheet with the thickness of 0.1mm-1.5mm and the width of 500mm-1500 mm.

The auxiliary layer is made of metal silicon nitride (Me: Si) N_XThe compound is formed by Me represents metal or metal alloy, (Me: Si) represents the ratio of Me to Si, index X represents the reaction coefficient of nitrogen element N, and Me is Ti, Cr, NiCr or NiV. The thickness of the auxiliary layer is 0.5nm-20 nm.

The thickness of the auxiliary layer is 2nm-5 nm.

The low-refractive-index layer is formed by silicon oxide or silicon aluminum oxide, is formed by electron beam evaporation and deposition, and has a thickness of 40-100 nm. The high refractive index layer is formed by titanium oxide, is formed by electron beam evaporation deposition, and has a thickness of 30nm-90 nm.

As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:

the utility model replaces the structure of matching the 'first auxiliary film layer' and the 'high-reflection silver film layer' in the previously disclosed CN110908027A document of the applicant by the composite layer of the aluminum-silver composite film structure, namely, the aluminum-silver composite film structure is introduced instead of using a relatively thick pure silver layer, thereby being beneficial to obviously reducing the cost.

And at least one of the composite layer structures is an aluminum bottom coating and a thin silver top coating, with a zinc oxide or metal doped zinc oxide layer (e.g., aluminum doped zinc oxide) in between, with an ultra-thin chromium or chromium alloy, nickel or nickel alloy, or nickel-chromium alloy, placed over it, and isolated by a structure placed at the interface between the zinc oxide or metal doped zinc oxide and the silver coating. Firstly, the composite layer of the aluminum-silver composite film structure defines a substructure, and the substructure can be not only applied independently (namely, only one composite layer is arranged), but also repeated for multiple times (namely, at least two composite layers are arranged), and both performance adjustment and cost control are more flexible. The zinc oxide layer or the metal-doped zinc oxide isolation layer between the aluminum and the silver has the function of inhibiting intermetallic diffusion. Placing an ultra-thin chromium layer or chromium alloy, nickel layer or nickel alloy or nickel chromium alloy on the interface between the zinc oxide or metal doped zinc oxide and the silver coating can improve durability, i.e., adhesion in a humid environment.

And an auxiliary layer, a low refractive index layer and a high refractive index layer on the composite layer are matched to form a high-reflection mirror coating structure which has the advantages of more economical cost, highest reflectivity, stable performance under the high-temperature condition of 180 ℃ or even higher and stable performance in the humid environment.

Drawings

FIG. 1 is a schematic structural diagram of a high-reflectivity mirror coating of the present invention.

FIG. 2 is a schematic view of the structure of a single composite layer of the present invention.

FIG. 3 is a schematic structural diagram of n composite layers according to the present invention.

FIG. 4 is an exemplary graph of the thickness of a reflectance output contrast adjusting silver coating in accordance with the present invention.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

Referring to FIG. 1, an improved high-reflectivity mirror coating is applied to the coating side of a metal substrate S0. The present embodiment is illustrated by a structure in which one side of the metal substrate S0 is a plated surface and the other side is a back surface, where in fig. 1, the side of the metal substrate S0 plated with the high-reflection mirror coating is the plated surface, and the side facing away from the plated surface is the back surface. Preferred metals for the metal substrate S0 include aluminum or alloys of aluminum. Preferred shapes for the metal substrate S0 include a metal strip or sheet having a thickness of 0.1mm to 1.5mm, a width of 500mm to 1500mm, and a length from a minimum of 10cm for the sheet to a maximum of several kilometers for the coiled metal strip.

With continued reference to fig. 1, the coating surface of the metal substrate S0 is composed of a surface treatment layer SF, at least one composite layer L10, an auxiliary layer L20, a low refractive index layer L30, and a high refractive index layer L40 from the metal substrate S0 upward in sequence. The surface treatment layer SF functions to smooth the surface and/or increase the hardness of the surface, for example, the metal substrate S0 is aluminum or an aluminum alloy and the surface treatment layer SF is an anodized aluminum thin film layer. Of course, the surface treatment layer SF may also be prepared by applying a layer of varnish or lacquer or even consist of only one highly polished metal surface. And a composite layer L10 of the Al-Ag composite film structure is formed on the surface treatment layer SF.

Referring to fig. 1, 2 and 3, the composite layer L10 includes a silver coating layer L14, an ultra-thin coating layer L13, an intermediate layer L12 and an aluminum coating layer L11, which are sequentially disposed, the intermediate layer L12 is made of zinc oxide or metal-doped zinc oxide, and the ultra-thin coating layer L13 is made of chromium, chromium alloy, nickel alloy and/or nickel-chromium alloy. For the same composite layer L10 structure, the aluminum coating L11 of the composite layer L10 is at the bottom and the silver coating L14 of the composite layer L10 is at the top. When at least two of the composite layers L10 are provided, the composite layers L10 are stacked one on another. That is, the composite layer L10 of such an aluminum-silver composite film structure defines a substructure that can be applied in multiple stacks. Specifically, fig. 2 is a structural schematic of a single composite layer L10, and fig. 3 is a structural schematic of n composite layers L10, and the occurrences of-1, -2, and-n in the reference numbers in fig. 3 indicate the repetition of the corresponding coating layer of each composite layer L10, i.e., the repetition of 1, 2, to n substructures. Specifically, the method comprises the following steps:

the aluminum coating L11 was deposited by magnetron sputtering, and the thickness could reach 50nm if only one composite layer L10 was provided. If there are several composite layers L10, the skilled engineer knows how to adjust the thickness of the aluminum coating L11 to below 50nm to achieve maximum reflected output.

The zinc oxide (ZnO) layer or the metal-doped zinc oxide barrier layer of the intermediate layer L12 described above has an effect of suppressing intermetallic diffusion. The intermediate layer L12 is prepared by a magnetron sputtering method, the thickness can reach 3nm-30nm, and the method is particularly dependent on the adjustment of the production efficiency of the coating and the arrangement number of the composite layers L10. The preferred choice for the intermediate layer L12 is aluminum doped zinc oxide (AZO). Research shows that the diffusion coefficient of aluminum-doped zinc oxide (AZO, 3 wt%) can be as low as 5.0E-21 or less. For comparison, the diffusion coefficient of silicon nitride (SiNx) may be below 5.5E-20. Silicon nitride is a commonly used diffusion barrier material.

The chromium (Cr) or chromium alloy, nickel (Ni) or nickel alloy or nickel chromium alloy (NiCr) layer of the ultra-thin coating L13 described above was placed at the interface between the intermediate layer L12 and the silver coating L14 to improve durability, i.e., adhesion in a humid environment. The coating is deposited by magnetron sputtering or other vacuum deposition techniques, and has a thickness of 1nm-5nm, preferably about 2.5 nm. A key problem with PVD coatings is the possible presence of so-called pinholes in the coating. These pinholes may still act as a conduction path for moisture. Depending on the size and density of the pinholes, these pinhole size defects may be exacerbated by long term exposure to extreme moisture. This effect is broadly explained as the lateral migration of silver atoms. It is further understood that water, such as from a humid environment, may adhere to the surface of the zinc oxide, weakening the adhesion to silver. This effect can be suppressed by applying a metallic interface between the zinc oxide and the silver coating L14. The metallic interfacial layer between the zinc oxide and the silver must be sufficiently thin so as not to inhibit the positive effect of the zinc oxide on the growth of the silver film, in particular the contribution to the spreading and crystal growth properties of the silver film. Studies by the applicant have shown that a thickness of around 2.5nm is optimal. The material of the ultra-thin coating L13 is selected such that a metal having high solubility for silver, such as aluminum or titanium, may help to inhibit lateral migration of silver in a humid environment and promote adhesion, but may also have disadvantages such as reducing the initial reflectance of silver by dissolving into silver. The use of pure chromium or chromium alloys, pure nickel or nickel alloys or nickel-chromium alloys according to the utility model avoids this disadvantage. Although the addition of a pure metal layer between the zinc oxide and the silver coating L14 will increase the complexity of the film system, it is advantageous for durability in humid environments and greatly reduces the cost since it is possible to significantly reduce the thickness of the silver coating L14.

The silver coating L14 is deposited by magnetron sputtering to a thickness of up to 50nm, but preferably not more than 40nm if only one of the composite layers L10 is provided. If there are several composite layers L10, the skilled engineer knows how to adjust the thickness of the silver coating L14 below 40nm to achieve maximum reflected output. By adjusting the thickness of the silver coating L14, not only can the reflected output be optimized, but also the cost, or more specifically, the cost versus reflected output, can be optimized.

Referring to fig. 1, the auxiliary layer L20 is disposed on the composite layer L10, and the auxiliary layer L20 is used for diffusion barrier and adhesion promotion of the highly reflective metal material, and also can be used as an anti-oxidation layer to protect the silver coating L14 on the top of the composite layer L10 from oxidation. The auxiliary layer L20 is made of silicon nitride (Me: Si) N_XThe compound, wherein Me represents a metal or a metal alloy, (Me: Si) represents the ratio between Me and Si, index X represents the reaction coefficient of nitrogen element N, and Me is Ti, Cr, NiCr or NiV, i.e., preferably a compound containing (Ti: Si) Nx, (Cr: Si) Nx, (NiCr: Si) Nx or (NiV: Si) Nx. The more preferable scheme of the auxiliary layer L20 is to use SiAl to replace pure Si for sputtering to improve the efficiency, wherein the content of Si to Al is 90% to 10%. I.e. (Me: Si) N_XBecause pure Si is not easy to sputter and the sputtering efficiency is low, SiAl is adopted for sputtering so as to improve the efficiency. The preferred coating technique for the auxiliary layer L20 is magnetron sputtering. The auxiliary layer L20 has a thickness of 0.5nm-20nm, preferablyIs 2nm-5 nm. On the auxiliary layer L20 was a low refractive index layer L30 followed by a high refractive index layer L40. The low refractive index layer L30 and the high refractive index layer L40 both serve as a reflectivity enhancing layer and protect the composite layer L10. The low refractive index layer L30 is preferably made of silicon oxide (SiOx) or silicon aluminum oxide (Si: Al) Ox, and the high refractive index layer L40 is preferably made of titanium oxide (TiOx). The preferred coating method for the low refractive index layer L30 and the high refractive index layer L40 is electron beam evaporation, but other PVD coating methods, such as magnetron sputtering, are also contemplated. The low refractive index layer L30 has a thickness of 10nm to 200nm, preferably 40nm to 100 nm. The high refractive index layer L40 has a thickness of 10nm to 200nm, preferably 30nm to 90 nm.

With reference to fig. 1-4, in accordance with the above-described embodiment, a skilled engineer can adjust the thickness of aluminum and the thickness of silver in the composite layer L10 and the number of composite layers L10 to optimize cost versus reflection output and optimize durability. Different applications may require different adjustments. Several examples of reflected output versus adjusted silver coating L14 thickness are given in fig. 4. The thinner the thickness of the silver coating L14, the lower the cost. But lower cost is traded off by lower reflected output. Where R _ vis in FIG. 4 represents the visible reflectance according to the standard CIE D65 specification for daylight.

This is further illustrated below with a specific experimental data.

Example 1:

composite layer L10:

L11 Al 25nm

l12 AZO (aluminum-doped zinc oxide) 5nm

L13 NiCr 5nm

L14 Ag 30nm

High-reflection mirror coating:

L40 TiOx 30nm

L30 SiOx 60nm

L20 (NiCr:SiAl)Nx 2nm

l10 Al-Ag composite film structure 65nm

SF anodized aluminum 1000-

S0 common aluminum 1085 alloy

The total visible reflectance R _ vis is measured in accordance with ISO 6719:2010 standard and the combined ISO/CIE standard, ISO 10526:1999/CIE S005/E-1998 (CIE standard illuminant for colorimetric quantitative analysis) and D65 illuminant at 2 observer angles.

97.6% after film coating (not tested)

97.6 percent of the mixture is baked at the high temperature of 180 ℃ for 168 hours

97.7% after exposure to 85 ℃, 85% r.H after 168 hours of ambient

'ao' (moisture test)

Coating adhesion was measured according to the hundred-grid cross scratch adhesion test described in ISO 2409:2013 and GB/T9286-.

After coating (not tested) grade 0, no stripping was observed.

The grade is 0 after the high-temperature baking for 168 hours at 180 ℃, and the film is not stripped.

Grade 0 after 168 hours of exposure to 85 ℃, 85% r.H.

'ao' (moisture test)

The test data shows that the structure of the utility model can obtain higher optical reflection performance and durability. And the data particularly shows high temperature stability.

The above description is only an embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by using the design concept should fall within the scope of infringing the present invention.

Claims

1. An improved high-reflection mirror coating comprises a high-refractive index layer, a low-refractive index layer and an auxiliary layer which are sequentially arranged, wherein the auxiliary layer is used for diffusion blocking and adhesion promotion of a high-reflection metal material; the high-reflection mirror surface coating is covered on the coating surface of the metal base material; the method is characterized in that: the composite layer is positioned between the auxiliary layer and the metal substrate; the composite layer comprises a silver coating, an ultrathin coating, an intermediate layer and an aluminum coating which are sequentially arranged, wherein the intermediate layer is made of zinc oxide or metal-doped zinc oxide, and the ultrathin coating is made of chromium, chromium alloy, nickel alloy and/or nickel-chromium alloy; when the composite layers are provided in at least two, the composite layers are arranged one on another.

2. An improved highly reflective specular coating as defined by claim 1, wherein: the aluminum coating and the silver coating are formed by magnetron sputtering deposition; when one composite layer is arranged, the thickness of the aluminum coating is less than or equal to 50nm, and the thickness of the silver coating is less than or equal to 50 nm; when at least two composite layers are provided, the thickness of the aluminum coating is less than 50nm, and the thickness of the silver coating is less than 40 nm.

3. An improved highly reflective specular coating as defined by claim 1, wherein: the middle layer is made of aluminum-doped zinc oxide.

4. An improved highly reflective specular coating as defined by claim 1, wherein: the middle layer is formed by magnetron sputtering deposition, and the thickness of the middle layer is 3nm-30 nm; the thickness of the ultrathin coating is 1nm-5 nm.

5. An improved highly reflective mirror coating according to claim 4, wherein: the thickness of the ultrathin coating is 2.5 nm.

6. An improved highly reflective mirror coating according to any of claims 1 to 5, wherein: the metal substrate is provided with a surface treatment layer on the film coating surface, the composite layer is covered on the surface treatment layer, the auxiliary layer is covered on the composite layer, the low refractive index layer is covered on the auxiliary layer, and the high refractive index layer is covered on the low refractive index layer; the surface treatment layer is an anodic oxidation layer, a varnish coating layer or a highly polished layer.

7. An improved highly reflective mirror coating according to claim 6, wherein: the metal substrate is made of aluminum or aluminum alloy, and the surface treatment layer is an anodic aluminum oxide film layer; the metal base material is a metal strip coiled material or a metal sheet with the thickness of 0.1mm-1.5mm and the width of 500mm-1500 mm.

8. An improved highly reflective specular coating as defined by claim 6, wherein: the auxiliary layer is made of metal silicon nitride (Me: Si) N_XThe compound is formed, wherein Me represents metal or metal alloy, (Me: Si) represents the ratio of Me to Si, index X represents the reaction coefficient of nitrogen element N, and Me is Ti, Cr, NiCr or NiV; the thickness of the auxiliary layer is 0.5nm-20 nm.

9. An improved highly reflective mirror coating according to claim 8, wherein: the thickness of the auxiliary layer is 2nm-5 nm.

10. An improved highly reflective specular coating as defined by claim 6, wherein: the low-refractive-index layer is formed by silicon oxide or silicon-aluminum oxide, is formed by electron beam evaporation and deposition, and has a thickness of 40-100 nm; the high-refractive-index layer is formed by titanium oxide, is formed by electron beam evaporation and deposition, and has a thickness of 30-90 nm.