Metal substrate ultraviolet broadband high reflection filter and preparation method thereof

Abstract

The application belongs to the field of optical film, and particularly relates to a metal base ultraviolet wideband high reflection filter and a preparation method thereof. The metal base ultraviolet wideband high reflection filter comprises a base, an absorption film system and a reflection film system. The absorption film system is composed of an absorption layer and an anti-reflection layer. The reflection film system is formed by alternately depositing high refractive index ZrO2 film layers and low refractive index SiO2 film layers, and the first layer and the last layer are both high refractive index ZrO2 film layers. The absorption film system has a total of 2 layers, the absorption layer is plated by using mixed film material of metal Cr and SiO2, the physical thickness of the absorption layer is 800-1200 nm, and the anti-reflection layer is a single layer of SiO2, and the physical thickness of the single layer of SiO2 is 40-70 nm. The application can effectively improve the ultraviolet reflectivity of the metal base ultraviolet wideband high reflection filter, has the characteristics of high production efficiency, high film layer hardness, stable spectrum and chemical performance, long replacement period and convenient maintenance, etc.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical film, in particular to a metal substrate ultraviolet broadband high reflection filter and a preparation method thereof. BACKGROUND

[0002] Ultraviolet light is a high-efficiency, environmentally friendly, energy-saving, and high-quality material surface technology. This technology has been applied from the earliest printed board to photoresist, ultraviolet light coating, ink, and adhesive, and its application field is expanding, forming a new industry.

[0003] Mercury lamp is a conventional light source commonly used in ultraviolet light source systems. It is widely used due to its wide ultraviolet spectral distribution, continuous energy, high power, and other advantages. Ultraviolet reflector is an essential key component of mercury lamp light source system. Its role is to collect and reflect the ultraviolet light emitted by the mercury lamp light source, improve the energy utilization rate of the mercury lamp light source, effectively increase the ultraviolet light irradiation intensity of the working surface, and improve the intensity and efficiency. According to the different base materials of the reflector, there are two types of ultraviolet reflectors-metal base reflector and glass base reflector. Compared with glass reflector, the commonly used aluminum alloy base ultraviolet reflector in metal has the advantages of light weight, fast heat dissipation, and convenient processing and molding, and is widely used in the ultraviolet industry.

[0004] Currently, aluminum alloy, stainless steel, and nickel alloy are commonly used as the base of ultraviolet reflectors. The mirror surface aluminum alloy plate with a thickness of 0.3-0.5mm is commonly used. The spectral reflection characteristics of the mirror surface aluminum plate are similar to those of aluminum film, and it has high reflectivity from the ultraviolet region to the infrared region. In actual use, the mercury lamp light source will radiate certain visible light and near-infrared light heat. The high temperature accumulated by long-term thermal radiation will cause the material to shrink and affect the precision. Especially for some heat-sensitive materials, the adhesion of the material may be affected. If the aluminum alloy base ultraviolet reflector has the spectral splitting effect of high reflection in the ultraviolet region and low reflection in the visible and near-infrared regions, the problem of infrared radiation heating can be solved.

[0005] In the existing technology query, the paper "Development of UV cold mirror aluminum reflector film" uses HfO2, SiO2, Cr, and TiN as plating film materials to design a filter film with high ultraviolet reflection, visible and near-infrared high absorption. In actual production, TiN film does not have good optical properties; HFO2 film has high absorption and many defects due to its material evaporation characteristics, which is not suitable for mass production. SUMMARY

[0006] The present application aims to provide a metal substrate ultraviolet broadband high reflection filter which can effectively improve the ultraviolet reflectivity of the metal substrate ultraviolet broadband high reflection filter, has high production efficiency, high film hardness, stable spectral and chemical properties, long replacement cycle and convenient maintenance, and a preparation method thereof.

[0007] To solve the above technical problems, the present application is implemented as follows:

[0008] A metal substrate ultraviolet broadband high reflection filter comprises a substrate, an absorbing film system and a reflecting film system; the absorbing film system is composed of an absorbing layer and an anti-reflection layer; the reflecting film system is composed of high-refractive-index ZrO2 film layers and low-refractive-index SiO2 film layers which are alternately deposited in sequence, and the first layer and the last layer are both high-refractive-index ZrO2 film layers.

[0009] Further, the absorbing film system comprises two layers in total, the absorbing layer is plated by using a mixed film material of metal Cr and SiO2, the physical thickness of the absorbing layer is 800-1200 nm, and the anti-reflection layer is a single-layer SiO2, the physical thickness of the single-layer SiO2 is 40-70 nm.

[0010] Further, the high-refractive-index ZrO2 film layers and the low-refractive-index SiO2 film layers are both non-periodic multilayer films, the physical thickness of the high-refractive-index ZrO2 is 14-55 nm, and the physical thickness of the low-refractive-index SiO2 is 30-100 nm.

[0011] Further, the number of layers of the high-refractive-index ZrO2 film layers and the low-refractive-index SiO2 film layers ranges from 33 to 41.

[0012] The preparation method of the metal substrate ultraviolet broadband high reflection filter comprises the following steps:

[0013] (1) substrate cleaning: the substrate is soaked and cleaned in a detergent, and then the surface of the substrate is cleaned by using a mixed ethyl ether alcohol solution with a mixing ratio of 1:3 and low-power ultrasonic waves;

[0014] (2) ion bombardment: the substrate is placed in a vacuum chamber, when the heating temperature reaches 200 degrees, the vacuum degree is greater than 3.0x10 -3 Pa, the ion source is started, and the substrate is ion bombarded for 5 minutes;

[0015] (3) Absorbing film system plating: after the ion cleaning of the substrate is completed, the ion source is closed; the e-type electron gun is used to complete the plating of the absorbing layer of the mixed film material of Cr and SiO2 and the anti-reflection layer of SiO2 in sequence;

[0016] (4) Ion assistance: after the plating of the absorbing film system is completed, the ion source is restarted;

[0017] (5) Reflection film system plating: after the ion source is restarted, the multi-layer film plating is performed; the two materials of high refractive index ZrO2 and low refractive index SiO2 are evaporated layer by layer by using the electron beam evaporation plus ion assistance process, wherein the high refractive index ZrO2 film layer is plated by using the high refractive index ZrO2 enhanced oxidation method on the basis of the electron beam evaporation plus ion assistance process.

[0018] Further, in the step (1), the detergent is an IPA solution, and the soaking time is 2 hours.

[0019] Further, in the steps (2) and (4), the ion source working parameters are the same, the ion source screen voltage is 500 V, the beam current is 250 mA, and the ion source working gas is oxygen.

[0020] Further, the steps (3) and (5) are both deposited into films in a 200-degree high-temperature environment.

[0021] Further, in the steps (3) and (5), the physical thickness of the plating is controlled by using the quartz crystal monitoring mode for all film layers.

[0022] Further, in the step (5), the high refractive index ZrO2 enhanced oxidation method is to supplement oxygen by using a pressure gauge during the electron gun evaporation of the high refractive index ZrO2, and the oxygen charging pressure of the pressure gauge is controlled at about 2.0*10 -2 Pa.

[0023] The whole plating process of the present application adopts a heating process at 200 degrees, which improves the film layer deposition density, reduces the film layer interface scattering, increases the optical constant of the film layer, effectively improves the reflectivity of the metal substrate ultraviolet wideband high reflection area, and increases the reflectivity by nearly 6% compared with the prior art. The absorbing film system in the present application is composed of only two layers of films, one is an absorbing layer, and the other is an anti-reflection layer, without the need for a connecting layer or a transition layer, and a multi-layer anti-reflection layer and other film layer structures. The absorbing film system of the present application simplifies the plating process, can improve the production efficiency and is suitable for batch manufacturing. The reflection film system in the present application selects film materials that are oxides, which have the advantages of high film hardness and stable chemical properties compared with other types of film materials, can ensure that the metal-based ultraviolet filter works continuously in a long-time high-temperature and high-intensity ultraviolet light irradiation environment, the film layer does not ablate and fall off, the spectral performance is stable, the replacement cycle is long during daily use, and the maintenance is convenient. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the descriptions below.

[0025] Figure 1 This is a schematic diagram of the structure of the metal substrate ultraviolet broadband high reflectance filter of the present invention;

[0026] Figure 2 This is a schematic diagram of the method for fabricating a metal substrate ultraviolet broadband high reflectance filter according to the present invention;

[0027] Figure 3 This is the measured reflectance spectrum of the metal substrate ultraviolet broadband high reflectance filter of the present invention. Detailed Implementation

[0028] A metal-based ultraviolet broadband high-reflection filter comprises a mirror-finish aluminum alloy substrate 1, an absorption film system, and a reflection film system. The absorption film system includes an absorption layer 2 and an antireflection layer 3. The absorption layer 2 is deposited using a mixed film material of metallic Cr and SiO2, with a physical thickness varying from 800 to 1200 nm. The antireflection layer 3 is a single layer of SiO2, with a physical thickness varying from 40 to 70 nm. The reflection film system is formed by alternating deposition of a high-refractive-index ZrO2 film layer 4 and a low-refractive-index SiO2 film layer 5, with the first and last layers being both high-refractive-index ZrO2 film layers 4. The ZrO2 film layer 4 and the SiO2 film layer 5 are optimized non-periodic multilayer films, with the physical thickness of the ZrO2 film layer 4 varying from 14 to 55 nm and the physical thickness of the SiO2 film layer 5 varying from 30 to 100 nm. The number of the two high- and low-refractive-index material layers ranges from 33 to 41 layers. The typical film structure and physical thickness of the metal substrate ultraviolet broadband high reflectance filter are shown in Table 1.

[0029] Table 1

[0030]

[0031] The above-mentioned method for fabricating a metal-based ultraviolet broadband high-reflection filter includes the following steps:

[0032] (1) Cleaning of aluminum alloy substrate: Soak the mirror aluminum alloy substrate 1 in IPA detergent for 2 hours, and then use a 1:3 ether alcohol solution to manually wipe the substrate surface clean.

[0033] (2) Ion bombardment: The aluminum alloy substrate 1 is placed in a vacuum chamber. When the heating temperature reaches 200 degrees and the vacuum degree is better than 3.0 × 10⁻⁶, the ion bombardment is carried out. -3After the Pa, open the ion source, ion source anode voltage of 500V, beam current of 250mA, ion source working gas for oxygen, the substrate ion bombardment 5 minutes.

[0034] (3) absorption film system plating: after the completion of the substrate ion cleaning, the ion source is closed. Ensure that the absorption film system and the aluminum alloy substrate thermal stress match, and then after plating the reflective film system, the aluminum-based optical filter is processed into a film layer without falling off by twice bending. Using an e-type electron gun, first complete the plating of the metal Cr and SiO2 mixed film material absorption layer 2, and then perform the plating of the single-layer SiO2 anti-reflection layer 3.

[0035] (4) ion assistance: after the completion of the plating of the absorption layer 2 and the anti-reflection layer 3, the ion source is reopened. The ion source anode voltage is 500V, the beam current is 250mA, and the working gas is oxygen.

[0036] (5) reflective film system plating: after the ion source is reopened, the multi-layer reflective film is plated. The ZrO2 high refractive index film material 4 and the SiO2 low refractive index film material 5 are both evaporated layer by layer by using the electron beam evaporation plus ion assistance process. Among them, the ZrO2 film layer 4 is plated by using the ZrO2 enhanced oxidation method on the basis of the electron beam evaporation plus ion assistance process, that is, in the process of evaporating the ZrO2 film layer 4 by the electron gun, the oxygen is supplemented by the pressure instrument, and the oxygen filling pressure is controlled at about 2.0×10 -2 Pa. Ensure that the ZrO2 film layer 4 is fully oxidized and reduced during the film forming process, effectively reduces the absorption of the ZrO2 film layer 4 in the ultraviolet short wave length range, and realizes the effect of wide-band high reflection spectrum of the reflective film system in the ultraviolet waveband. The plating spectrum curve is shown in Figure 3 .

[0037] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that for ordinary skilled persons in the art, various improvements and changes can be made without departing from the principles of the present application, and these improvements and changes should also be considered as the scope of protection of the present application.

Claims

1. A metal-based ultraviolet wide-band high-reflectance filter, characterized in that, The application relates to a high-refractive-index ZrO2 film layer and a low-refractive-index SiO2 film layer, and belongs to the technical field of high-refractive-index film and low-refractive-index film.

2. The metal-based ultraviolet wide-band high reflection filter according to claim 1, characterized in that: The high-refractive-index ZrO2 film layer and the low-refractive-index SiO2 film layer are both non-periodic multilayer films, the physical thickness of the high-refractive-index ZrO2 is 14-55nm, and the physical thickness of the low-refractive-index SiO2 is 30-100nm.

3. The metal-based ultraviolet wide-band high-reflectance filter according to claim 2, wherein: The number of layers of the high-refractive-index ZrO2 and the low-refractive-index SiO2 film layer ranges from 33 to 41.

4. The method for preparing the metal substrate ultraviolet wideband high reflection filter according to any one of claims 1-3, characterized in that, The application further discloses a preparation method of the high-refractive-index film and the low-refractive-index film. (1) substrate cleaning: the substrate is soaked in a detergent for cleaning, and then the surface of the substrate is cleaned by using a mixed ethyl ether alcohol solution with a mixing ratio of 1:3 and low-power ultrasonic waves; (2) Ion bombardment: the substrate is put into the vacuum chamber, when the heating temperature reaches 200 degrees, the vacuum degree is greater than 3.0*10 -3 After 30 minutes, the ion source is turned on, and the substrate is ion bombarded for 5 minutes; (3) absorption film system plating: after the ion cleaning of the substrate is completed, the ion source is closed; the plating of the absorption layer of the mixed film material of metal Cr and SiO2 and the plating of the anti-reflection layer of SiO2 are completed by using an e-type electron gun; (4) ion assistance: after the plating of the absorption film system is completed, the ion source is restarted; (5) reflection film system plating: after the ion source is restarted, the multilayer film plating is carried out; the two materials of the high-refractive-index ZrO2 and the low-refractive-index SiO2 are evaporated layer by layer by using an electron beam evaporation and ion assistance process, wherein the high-refractive-index ZrO2 film layer is plated by using a high-refractive-index ZrO2 enhanced oxidation method on the basis of the electron beam evaporation and ion assistance process.

5. The method for fabricating a metal-substrate ultraviolet broadband high-reflection filter according to claim 4, characterized in that: In the step (1), the detergent is an IPA solution, and the soaking time is 2 hours.

6. The method for fabricating a metal-substrate ultraviolet broadband high-reflection filter according to claim 5, characterized in that: In the steps (2) and (4), the working parameters of the ion source are the same, the screen voltage of the ion source is 500V, the beam current is 250mA, and the working gas of the ion source is oxygen.

7. The method for fabricating a metal-substrate ultraviolet broadband high-reflection filter according to claim 6, characterized in that: The steps (3) and (5) are both carried out in a high-temperature environment of 200 degrees.

8. The method for fabricating a metal-substrate ultraviolet broadband high-reflection filter according to claim 7, characterized in that: In the steps (3) and (5), the physical thickness of the plating is controlled by using a quartz crystal monitoring mode.

9. The method for fabricating a metal-substrate ultraviolet broadband high-reflection filter according to claim 8, characterized in that: In step (5), the high refractive index ZrO2reinforced oxidation method is to use a pressure gauge to supplement oxygen during the electron gun evaporation of high refractive index ZrO2, and the oxygen supplementing pressure of the pressure gauge is controlled at 2.0×10 -2 Pa or so.

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