Display film material and preparation method therefor

Abstract

The present invention relates to a display film material and a preparation method therefor. The display film material comprises a substrate, and a light-modulating layer arranged on the substrate, wherein the substrate is made of an optically transparent material; and the light-modulating layer is formed by alternately stacking a low-refractive-index material and a high-refractive-index material, the difference between the refractive indexes of the low-refractive-index material and the high-refractive-index material being greater than 0.4. After being subjected to the action of the light-modulating layer and the substrate, light can achieve a visible-light transmittance of 90% or above, a near-infrared blocking rate of up to 80% or above, and a high transmittance at the band of 940-1000 nm and a mid-infrared emissivity of up to 90% or above, thereby ultimately realizing a cooling effect of 3-8 degrees centigrade.

Description

A display film material and a preparation method thereof TECHNICAL FIELD

[0001] The present application relates to a film, in particular to a display film material and a preparation method thereof. BACKGROUND

[0002] With the growth of the global population and the continuous development of society, the problem of climate warming is becoming increasingly serious, which leads to an increase in the demand for refrigeration energy consumption. The traditional active refrigeration means is a compression-based cooling system, which consumes a large amount of electricity and produces a large amount of carbon dioxide, and the refrigerant used in the compression cooling system, such as freon, also destroys the ozone layer and causes serious environmental problems. Radiation refrigeration, which is significantly different from the traditional refrigeration means, is a passive refrigeration method that emits heat to the cold universe through thermal radiation. The atmosphere of the earth has different transmittances to electromagnetic waves of different wavelengths, among which the transmittance to electromagnetic waves of 8-13 mu m band is extremely high, i.e. the "atmospheric window". Therefore, an excellent radiation refrigeration surface should have as high emissivity as possible in the 8-13 mu m band, while strongly reflecting sunlight (0.3-2.5 mu m), so as to achieve spontaneous cooling without consuming any energy. In summary, the radiation refrigeration technology can save energy and at the same time alleviate the problems of greenhouse effect, environmental pollution and the like caused by the traditional refrigeration.

[0003] With the development of nanophotonics and advanced manufacturing technology, photonic crystals and metamaterials are first applied to radiation refrigeration materials. Nanophotonic crystals refer to nanophotonic materials with various layered structures and super surface structures formed by coating processes such as magnetron sputtering, electron beam evaporation or micro-nano processing of some semiconductor materials, so as to realize selective high emission in a specific mid-infrared band.

[0004] The radiation spectrum of ordinary materials is usually wide, while photonic materials can be used to design a controllable, narrow-band emission spectrum heat source, which is particularly needed in radiation refrigeration. At present, many nano-structured materials have been applied to radiation refrigeration. However, most of the current radiation refrigeration materials are applied to outdoor buildings such as walls and roofs, and are less applied to display devices, because the display devices have higher requirements for the radiation refrigeration materials in the spectrum.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a radiation refrigeration film suitable for display devices, especially a radiation refrigeration film suitable for display devices integrated with sensors. Based on this purpose, the present application provides a display film material, which meets the requirements of high visible light transmittance, high near-infrared reflectivity and high mid-infrared emissivity through the design of selected materials and structures.

[0007] The technical scheme adopted by the present application is: a display film material, comprising a substrate and a light regulation layer arranged on the substrate, the substrate has an absorption rate of <5% in the visible light of 400-780 nm, preferably no absorption, and a transmittance of >90%, and an absorption rate of <5% in the near-infrared light of 900-1100 nm, preferably no absorption, and can be an organic material or an inorganic material, and can be a flexible material or a rigid material, and preferably a mixture of one or more materials selected from Glass, PET, PC, PMMA, PE and COP. The light regulation layer is used to regulate the optical properties of the film material, make up for the deficiency of the substrate in the optical properties, and enhance the operability of the material. The light regulation layer is formed by depositing a plurality of organic or / and inorganic materials. After the light passes through the light regulation layer and the substrate, the transmittance in the visible light of 400-780 nm is greater than 80%, preferably greater than 90%, the emissivity in the mid-infrared waveband of 8-13 μm is greater than 85%, preferably greater than 95%, and the reflectivity in the near-infrared waveband of 900-1400 nm is greater than 70%, and the transmittance in the waveband of 940-1100 nm is >70%.

[0008] More preferably, the substrate has an absorption rate of <1% in the waveband of 400-780 nm, and a transmittance of >90%, and an absorption rate of <1% in the waveband of 900-1400 nm. The light regulation layer is formed by alternately stacking low-refractive-index materials and high-refractive-index materials. The difference between the refractive indexes of the low-refractive-index materials and the high-refractive-index materials is greater than 0.5. After the light passes through the light regulation layer and the substrate, the transmittance in the waveband of 400-780 nm is greater than 90%, the emissivity in the waveband of 8-13 μm is greater than 85%, the reflectivity in the waveband of 900-1400 nm is greater than 80%, and the transmittance in the waveband of 940-1000 nm is greater than 90%.

[0009] In the present application, the light regulation layer is formed by stacking at least two materials, and the difference between the refractive indexes of the two materials is greater than 0.4, preferably greater than 0.5, and more preferably the difference between the refractive indexes is 0.5-0.8. The material with the higher refractive index is referred to as the high-refractive-index material. The material with the lower refractive index is referred to as the low-refractive-index material. The high-refractive-index material and the low-refractive-index material are alternately stacked to interfere with, selectively transmit or reflect light of different wavebands, thereby realizing spectral regulation. When the difference between the refractive indexes of the high-refractive-index material and the low-refractive-index material is greater than 0.4, the light in the wavebands of 400-780 nm and 940-1100 nm can have a refractive index close to that of air (1) by performing multilayer film admittance matching interference, thereby realizing high transmittance in the wavebands; and the light in the waveband of 900-1400 nm (excluding 940-1100 nm) can have a refractive index far from that of air (infinity), thereby realizing high reflectivity in the waveband.

[0010] The number of layers of the high refractive index material and the low refractive index material can be the same or different, and the high refractive index material can be one material or multiple materials, and similarly, the low refractive index material can be one material or multiple materials. The present application preferably has at least two layers of material in the thickness range of 25 nm to 500 nm, and the refractive index difference between the two layers of material is 0.5 to 0.8. Further detailed explanation is that when the film layer is lower than the preferred thickness, the following problems will occur during the processing: (1) poor film uniformity, poor cooling effect and sensor sensitivity, and even affect normal work; (2) film stress disorder, unable to form stress compensation with adjacent layers, and further cause film cracking; (3) magnify the error influence in the normal processing, thus leading to inaccurate control of spectral deviation. When the film layer is higher than the preferred thickness, the following problems will occur: local film stress is too large, film material is used excessively, appearance is poor, equipment failure rate is high, etc. The refractive index difference between the two layers of material is preferably 0.5 to 0.8. On the one hand, this refractive index difference ensures sufficient refractive index difference, achieves excellent spectral regulation effect with fewer layers, on the other hand, it helps to select more suitable materials for product processing, and on the other hand, below this refractive index difference will lead to low near-infrared reflectivity, thus affecting the cooling effect of radiative cooling.

[0011] The low refractive index material in the light regulation layer is provided in multiple layers, and the high refractive index material is provided in multiple layers, and the total number of layers is preferably 38 to 50 layers. Below this number of layers, the optical effect of each waveband cannot be coordinated, and above this number of layers, the bonding force between the light regulation layer and the substrate will be poor, and the light transmittance will also be reduced. Each low refractive index material and each high refractive index material is a metal oxide or a non-metal oxide, and the transmittance of each low refractive index material and each high refractive index material in the visible light waveband is higher than 90% in the nanometer thickness range. Each low refractive index material can be the same or different, and is preferably selected from one or more combinations of TiO2 [titanium oxide], Ti3O5 [trititanium pentoxide], ZrO2 [zirconium oxide], CeO2 [cesium oxide], HfO2 [hafnium oxide], Nb2O5 [di-niobium pentoxide], Ta2O5 [di-tantalum pentoxide]; each high refractive index material can be the same or different, and is preferably selected from one or more combinations of SiO2 [silicon dioxide], SiO [silicon monoxide], MgF2 [magnesium fluoride], Al2O3 [aluminum trioxide], PR04 [silicon-aluminum mixture], PR06 [silicon-aluminum mixture], ice crystal, and AlF3 [aluminum fluoride]. The above high refractive index material has no light absorption in the required spectral waveband, which is beneficial to enhancing the light regulation effect.

[0012] The thickness of the high refractive index material and the low refractive index material affects the light control effect of the material layer, preferably, the thickness of the high refractive index material is 10-200 nm, and the thickness of the low refractive index material is 20-300 nm, which can ensure the uniformity of the material layer, prevent the film stress from being too large, reduce the possibility of film cracking, sharply distinguish the light beams of different wave bands, control the paths of the light beams of different wave bands, effectively distinguish the visible light, near-infrared light and mid-infrared light, and increase the transmittance of the visible light wave band and the reflectivity of the near-infrared wave band based on the interference of light.

[0013] The high refractive index material and the low refractive index material in the application are not only limited to the immediately adjacent interleaved layering, but also can be interleaved layering of several layers of low refractive index material, high refractive index material and then low refractive index material, that is, the layering mode can be (1) one layer of high refractive index material - one layer of low refractive index material - one layer of high refractive index material; (2) two layers of high refractive index material - one layer of low refractive index material - one layer of high refractive index material - two layers of low refractive index material. The mode (2) can enhance the controllability of the wave band, and make the light of different wave bands present different optical properties.

[0014] The light control layer in the application can be directly deposited on the substrate, or a transition layer can be first deposited on the substrate. The existence of the transition layer is beneficial to enhancing the bonding stability between the light control layer and the substrate. The transition layer is preferably an organic material, which is referred to as a first organic layer. The SA, RA, SHA and phthalocyanine organic material are produced by the Korean ceko, Nano Primer company, and the model of the organic material is SA, RA, SHA. The SA, RA, SHA and phthalocyanine organic material has no light absorption in the visible light wave band when used as the first organic layer, reduces the influence of the film layer on the transmittance of the visible light wave band, and has excellent impact resistance, thereby improving the bonding stability between the substrate and the light control layer. A second organic layer is arranged above the light control layer, that is, on the side of the light control layer away from the substrate. The second organic layer is a hydrophobic and oleophobic organic material, preferably a fluorine-containing organic material, and more preferably AF (anti-fingerprint film). The AF has extremely low surface energy and can achieve the function of surface self-cleaning. The arrangement of the second organic layer can prevent the film material of the application from being contaminated by water or oil stains during use, and has the function of self-cleaning. In addition, the AF has excellent spectral control performance. The thickness of the AF layer is preferably (10-40) nm. When the thickness of the AF is less than 10 nm, it is difficult to form a dense film layer on the surface, resulting in poor hydrophobic effect. When the thickness of the AF is more than 40 nm, an oil stain layer is formed on the surface, which cannot be effectively combined with other film layers, and the thick film layer will cause material waste and surface discoloration.

[0015] The second organic layer needs to be deposited into a film by using a resistance evaporation process, and the current is preferably (30-200) mA, and the plating rate is (3-9) A / s; if the evaporation rate is too low, the kinetic energy of the AF material is insufficient, the film thickness is low, and the film compactness is poor; and if the evaporation rate is too high, the product uniformity is poor.

[0016] As a preferred solution, the second organic layer is arranged on the substrate, specifically arranged on the side of the substrate away from the light control layer; when the film is attached, the light control layer is in contact with the display screen through the AB glue, and the second organic layer is arranged on the surface. This arrangement enhances the hydrophobic property and the friction resistance of the AF material.

[0017] As a preferred solution, the high-refractive-index material is TiO2, the low-refractive-index material is SiO2, the light control layer is arranged by alternately stacking TiO2 and SiO2, there are 41 layers in total, the first organic layer is SHA, the second organic layer is AF, and the particle size of the high-refractive-index material and the low-refractive-index material is (1-3) mm. The production process is as follows:

[0018] The plating temperature of the light control layer is 100℃, and the vacuum degree is set to 1*10 -3 Pa. The energy of the SiO2 ion source for plating assistance is 170V, 6A; the energy of the TiO2 ion source for plating assistance is 200V, 8A; the SHA is processed by using an EB (electron beam evaporation) method, and the current is 10-60mA; and the AF is processed by using a resistance evaporation process, and the heating current is 100-200mA.

[0019] As a preferred solution, the high-refractive-index material is TiO2 (n=2.35@500nm), the low-refractive-index material is SiO2 (n=1.46@550nm) & MgF2 (n=1.38@550nm), the high-refractive-index material and the low-refractive-index material are arranged in 41 layers in total, the particle size of the high-refractive-index material and the low-refractive-index material is 1-3mm, the first organic layer is SHA, the second organic layer is AF, and the preparation process used is as follows:

[0020] The plating temperature is 150℃, and the vacuum degree is set to 1.5*10 -3 Pa. The energy of the SiO2 ion source for plating assistance is 200V, 7A; the energy of the TiO2 ion source for plating assistance is 250V, 7.5A; the SHA is processed by using an EB method, and the current is 10-60mA; and the AF is processed by using a resistance evaporation process, and the heating current is 100-200mA.

[0021] As a preferred solution, the high refractive index material in the application is Ta2O5 (n = 2.32@500nm) and the low refractive index material is SiO2 (n = 1.46@550nm), the total number of layers of the high refractive index material and the low refractive index material is 49 layers, the particle size of the high refractive index material and the low refractive index material is 1-3mm, the first organic layer is SA, the second organic layer is AF, and the preparation process used is:

[0022] The coating temperature is selected as 100 DEG C, and the vacuum degree is set as 1*10 -3 The energy of the SiO2 ion source for plating is 170V, 6A; the energy of the Ta2O5 ion source for plating is 200V, 8A; the SA is processed by the EB mode, and the current is 10-60mA; the AF is processed by the resistance evaporation process, and the heating current is 100-200mA.

[0023] The beneficial effects of the application include that the film is designed by the structure of the multilayer film to regulate the spectral performance of different wave bands, so that the film material in the application has the following performances (1) high near-infrared barrier performance, (2) does not affect the sensor sensing effect, (3) effectively isolates the incidence of other energy of the sunlight wave band, (4) emits heat in the form of electromagnetic waves to the natural cold source in the universe through the thermal infrared wave band, so as to realize the maximum radiation cooling effect.

[0024] The film material in the application is alternately arranged by high and low refractive index materials, the interference effect of light is utilized, the stacking of different materials increases the transmittance of the visible light wave band, the reflectivity of the near-infrared wave band and the emissivity of the mid-infrared wave band. Ultimately, the visible light transmittance is more than 90%, the near-infrared barrier rate is more than 80%, the mid-infrared wave band emissivity is more than 90%, the 940-1000nm wave band has a high transmittance of more than 90%, and a cooling effect of 3-8 degrees is achieved.

[0025] The film material in the application can be attached to the surface of any material for cooling, such as glass, wall, roof, display device of electronic equipment, and is an effective tool for energy saving and emission reduction. The surface of the film material is added with an organic packaging layer, so that the product has excellent anti-aging properties, excellent hydrophobicity, anti-fouling and wear resistance during use.

[0026] When the film material in the application is applied to a display device, a large number of sensors are integrated on the screen of the flat panel display device, especially a product represented by a mobile phone, such as a fingerprint sensor, a Face ID sensor, a distance sensor, an ambient light sensor, a TOF sensor and the like. The working wavelength of these sensors is mainly concentrated in the visible light or near-infrared wave band (commonly known as 940nm). The film material in the application can realize high transmittance of the 940nm wave, and ensure the sensitivity of the sensor.

[0027] According to Planck's law of thermal radiation: B(λ, T) = (2hc 2 / λ 5 )*(1 / (e^(hc / λkT)-1), wherein B(λ, T) is the radiation energy density per unit area per unit wavelength range, λ is the wavelength, T is the absolute temperature, c is the speed of light, h is the Planck constant, and k is the Boltzmann constant. The working temperature of a product related to life is between 30-70℃, and in particular, the working temperature of a display device is usually between 30-60℃, and the main wavelength range of thermal radiation thereof is located in the atmospheric window region. The present application is attached to the screen cover glass of a display device, and can be controlled in a wide spectrum to achieve solar radiation thermal radiation isolation, to optimize the working wavelength of an optical sensor to avoid affecting the work, and to improve the thermal radiation capacity of the product in the 8-13μm atmospheric window band. BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 is a structural diagram of the film material in Example 1;

[0029] FIG. 2 is the transmittance of the film before and after coating in Example 1;

[0030] FIG. 3 is the emissivity of the film material in Example 1;

[0031] FIG. 4 shows the detection values of the display film, the display without the film, and the ambient temperature;

[0032] FIG. 5 is a structural diagram of the film material in Example 2. DETAILED DESCRIPTION

[0033] The present application will be further explained in detail below in conjunction with the drawings and specific examples, but it should be understood that the scope of protection of the present application is not limited by the specific examples.

[0034] Example 1

[0035] In this embodiment, the substrate of the film material is a commercial mobile phone tempered film, the high refractive index material in the light regulation layer is TiO2(n=2.35@500nm), and the low refractive index material is SiO2(n=1.46@550nm). The light regulation layer is obtained by an electron beam evaporation coating system, and there are 39 layers, which are arranged from close to the substrate to far from the substrate: TiO2 layer, SiO2 layer, TiO2 layer, SiO2 layer, TiO2 layer, and the thickness and coating rate of each layer are shown in Table 1, and the particle size of the high refractive index material and the low refractive index material is selected to be 1-3mm. The organic layer adopts SHA&AF. The structure of the film material is shown in FIG. 1, the first organic layer is deposited on the substrate, and the second organic layer is deposited on the back side of the substrate. The number 1 / 2 / 3...n in the figure is the layer number label of the light regulation layer.

[0036] The coating temperature of the light regulation layer is selected to be 100℃, the vacuum degree is 1*10 -3The SiO2ion source assisted plating energy is 170 V, 6 A; the TiO2ion source assisted plating energy is 200 V, 8 A; the SHA is processed in an EB mode, with a current of 10-60 mA; and the AF is processed in a resistive evaporation process, with a heating current of 100-200 mA.

[0037] Table 1: Materials, thicknesses, and plating rates of each layer

[0038] The original glass (commercial mobile phone tempered film) and the glass after plating were tested respectively.

[0039] 1. The reflectivity of the commercial glass and the glass after plating in the solar waveband was tested using a UV-vis-nir spectrophotometer (uv3600, Shimadzu) equipped with an integrating sphere model (ISR-3100), with a test range of (0.3-2.5) μm.

[0040] The reflectivity of the glass before and after plating is shown in FIG. 2, and the results show that after adding the radiation refrigeration film of the present application, the transmittance of the glass in the near-infrared waveband is significantly reduced, from 90% for the original glass to about 30%.

[0041] 2. The emissivity of the commercial glass and the glass after plating in the mid-infrared waveband was tested using a Fourier transform infrared (FT-IR) spectrometer (Nicolet IS50, ThermoFisher) and a gold integrating sphere (IntergatIR MIR, Pike) and a mercury cadmium telluride detector. The emissivity of the glass before and after plating is shown in FIG. 3, and the results show that after adding the radiation refrigeration film of the present application, the emissivity of the glass in the mid-infrared waveband is significantly improved, especially in the atmospheric window (8-13 μm), from an average of less than 0.8 for the original glass to more than 0.9.

[0042] 3. The cooling effect of the commercial glass and the glass after plating was tested. A temperature tester was placed on the glass after plating, the original glass (attached to a commercial mobile phone under the condition of continuous work of the bright screen), and the air, and the temperature changes under the three conditions were recorded. The lower the temperature, the better the refrigeration effect. The instrument used was a K-type thermocouple of Omega. The results are shown in FIG. 4. Under outdoor conditions at an ambient temperature of about 30°C, the glass after plating can reduce the working temperature of the mobile phone by 3-8°C, with a significant cooling effect.

[0043] 4. The hydrophobic performance of the glass after plating was tested using a Theta contact angle tester (LSA100, LAUDA Scientific), and the average value of the static contact angle was measured to be more than 115°, with excellent hydrophobic performance.

[0044] Example 2

[0045] The base of the film material in this embodiment is tempered glass, the low refractive index material in the light control layer is SiO2, and the high refractive index material is TiO2. The light control layer is obtained by an electron beam evaporation coating system, and is composed of 36 layers. The particle size of the high refractive index material and the low refractive index material is selected to be 1-3 mm. The organic layer adopts SHA&AF. After coating, the structure is shown in FIG. 5. The first organic layer is deposited between the light control layer and the glass base as a buffer transition layer, and the second organic layer is deposited on the light control layer.

[0046] The coating temperature is selected to be 150°C, and the vacuum degree is set to be 1.5*10 -3 The energy of the SiO2 ion source for coating is 200V, 7A; the energy of the TiO2 ion source for coating is 250V, 7.5A; the SHA is processed by EB mode, and the current is 10-60mA; the AF is processed by a resistance evaporation process, and the heating current is 100-200mA.

[0047] Table 2: Material, thickness and coating rate of each layer

[0048] The original glass (commercial mobile phone tempered film) and the coated glass are tested respectively.

[0049] 1. The reflectivity of the commercial glass and the coated glass in the solar wave band is tested. The instrument used is a UV-vis-nir spectrophotometer (uv3600, Shimadzu) equipped with an integrating sphere model (ISR-3100), and the test range is (0.3-2.5) μm.

[0050] The reflectivity of the glass before and after coating shows that after adding the radiation refrigeration film of the present application, the transmittance of the glass in the near-infrared wave band is obviously reduced, from 90% of the original glass to about 30%.

[0051] 2. The emissivity of the commercial glass and the coated glass in the mid-infrared wave band is tested. The instrument used is a Fourier transform infrared (FT-IR) spectrometer (Nicolet IS50, ThermoFisher) and a gold integrating sphere (IntergatIR MIR, Pike) and a mercury cadmium telluride detector. The emissivity results of the glass before and after coating show that after adding the radiation refrigeration film of the present application, the emissivity of the glass in the mid-infrared wave band is obviously improved, especially in the atmospheric window (8-13 μm), from an average of less than 0.8 of the original glass to more than 0.9.

[0052] 3. The reflectivity of the glued screen of the processed product is tested using a color difference meter (HC-CR8W), and the test reflectivity Y is about 1.8. The reflectivity of the glued screen of the original glass is tested, and the test reflectivity Y is about 5.3. The processed product has obvious anti-glare and anti-fog functions.

[0053] 4. Test the cooling effect of commercial glass and coated glass. Place the temperature tester on the coated glass, the original glass (attached to the commercial mobile phone under the condition of bright screen continuous work) and the air, and record the temperature change under the three conditions. The lower the temperature, the better the cooling effect. The instrument used is K-type, Omega thermocouple. Under the outdoor condition of ambient temperature about 30℃, the coated glass can reduce the working temperature of the mobile phone by 3-8℃, which has significant cooling effect.

[0054] 4. Test the hydrophobicity of the coated glass. The instrument used is Theta contact angle tester (LSA100, LAUDA Scientific), and the average value of the static contact angle is more than 115°, which has excellent hydrophobicity.

[0055] Example 3

[0056] The substrate of the film material in this example is tempered glass, the low refractive index material in the light control layer is SiO2, and the high refractive index material is Ta2O5 (n = 2.32@500nm). The light control layer is obtained by an electron beam evaporation coating system, and is composed of 39 layers, from the substrate to the far substrate, it is TA2O5 layer, SIO2 layer, TA2O5 layer, SIO2 layer……TA2O5 layer, SIO2 layer, and the particle size of the high refractive index material and the low refractive index material is 1-3mm. The first organic layer uses SA, and the second organic layer uses AF, which is a granular material. The first organic layer is arranged between the light control layer and the substrate material, and the second organic layer is arranged on the side of the light control layer away from the first organic layer.

[0057] The coating temperature is selected as 100℃, and the vacuum degree is set as 1*10 -3 The energy of SiO2 ion source assisted coating is 170V, 6A; the energy of Ta2O5 ion source assisted coating is 200V, 8A; SA is processed by EB method, and the current is 10-60mA; AF is processed by resistance evaporation process, and the heating current is 100-200mA.

[0058] Table 3 Material, thickness and coating rate of each layer

[0059] Test the original glass (commercial mobile phone tempered film) and the coated glass respectively.

[0060] 1. Test the reflectivity of commercial glass and coated glass in the solar wave band. The instrument used is UV-vis-nir spectrophotometer (uv3600, Shimadzu) equipped with integral sphere model (ISR-3100), and the test range is (0.3-2.5) μm.

[0061] The reflectivity of the glass before and after coating shows that the transmittance of the glass in the near-infrared band is obviously reduced from 90% of the original glass to about 40% after adding the radiation cooling film of the application.

[0062] 2. The emissivity of the commercial glass and the coated glass in the mid-infrared band was tested. The instrument used was a Fourier transform infrared (FT-IR) spectrometer (Nicolet IS50, ThermoFisher) and a gold integrating sphere (IntergatIR MIR, Pike) and a mercury cadmium telluride detector. The emissivity of the glass before and after coating shows that the emissivity of the glass in the mid-infrared band is obviously improved after adding the radiation cooling film of the application, especially in the atmospheric window (8-13 μm), from an average of less than 0.8 of the original glass to more than 0.9.

[0063] 3. The cooling effect of the commercial glass and the coated glass was tested. The temperature tester was placed on the coated glass, the original glass (attached under the condition of continuous work of the commercial mobile phone bright screen) and the air, and the temperature changes under the three conditions were recorded. The lower the temperature, the better the cooling effect. The instrument used was a K-type thermocouple of Omega. Under the outdoor condition of an ambient temperature of about 30°C, the coated glass can reduce the working temperature of the mobile phone by 3-6°C, and has obvious cooling effect.

[0064] 4. The hydrophobic performance of the coated glass was tested. The instrument used was a Theta contact angle tester (LSA100, LAUDA Scientific). The average value of the static contact angle was more than 115°, and the hydrophobic performance was excellent.

[0065] The above examples are only used to illustrate the technical solutions of the application and not to limit it. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the application.

Claims

1. A display film material, characterized in that: The device includes a substrate and a light modulation layer disposed on the substrate. The substrate has an absorptivity of less than 5% and a transmittance of greater than 80% in the 400–780 nm wavelength range, and an absorptivity of less than 5% in the 900–1400 nm wavelength range. The light modulation layer is formed by alternating layers of low-refractive-index and high-refractive-index materials, with a refractive index difference of greater than 0.5 between the low-refractive-index and high-refractive-index materials. After light passes through the light modulation layer and the substrate, the transmittance is greater than 80% in the 400–780 nm wavelength range, the emissivity is greater than 85% in the 8–13 μm wavelength range, the reflectivity is greater than 70% in the 900–1400 nm wavelength range, and the transmittance is greater than 80% in the 940–1000 nm wavelength range.

2. The display film material according to claim 1, characterized in that: The number of low-refractive-index material layers and high-refractive-index material layers may be the same or different. The total number of spectral modulation layers is 28 to 50. The composition and thickness of each low-refractive-index material layer are the same or different. The composition and thickness of each high-refractive-index material layer are the same or different. The light modulation layer is disposed directly or indirectly on the substrate.

3. The display film material according to claim 2, characterized in that: The light modulation layer is disposed on the substrate through a first organic layer. The first organic layer has a light absorption rate of less than 5% in the 400-780nm wavelength band. The first organic layer is selected from one or more of SA, RA, SHA, and phthalocyanine organic compounds.

4. The display film material according to claim 1, characterized in that: The spectral modulation layer satisfies at least one or more of the following combinations. —The high refractive index material is selected from one or more of TiO2, Ti3O5, ZrO2, CeO2, HfO2, Nb2O5, and Ta2O5; —The low refractive index material is selected from one or more of SiO2, SiO, MgF2, Al2O3, PRO4, PRO6, cryolite, and AlF3; —The thickness of the low-refractive-index material is 20-300 nm; —The thickness of the high refractive index material is 10-200 nm.

5. The display film material according to claim 1, characterized in that: A second organic layer is disposed on the side of the substrate opposite to the light modulation layer, or on the side of the light modulation layer opposite to the substrate, wherein the second organic layer satisfies one or more of the following: —The second organic layer is a fluorinated organic compound; —The second organic layer is AF; —The water droplet angle of the second organic layer is greater than 115°; —The thickness of the second organic layer is 10-40 nm; —The second organic layer is deposited by a barrier evaporation process, with the preferred barrier evaporation current being (30-200) mA and the deposition rate being (3-9) A / s.

6. The display film material according to claim 1, characterized in that: A first organic layer and a second organic layer are respectively disposed on both sides of the substrate. The optical control layer is disposed on the side where the first organic layer is disposed. The optical control layer has 41 to 49 layers of TiO2 and SiO2 stacked alternately. The thickness of the TiO2 layer is (15-300) nm and the thickness of the SiO2 layer is (10-200) nm. The first organic layer is SHA and the second organic layer is AF.

7. The display film material according to claim 1, characterized in that: In the thickness direction of the light modulation layer, within any thickness range of 25nm to 500nm, at least two layers of material with a refractive index difference of 0.5 to 0.8 are provided.

8. The display film material according to claim 1, characterized in that: After passing through the light modulation layer and the substrate, the light has a transmittance of more than 90% in the visible light band, an emissivity of more than 95% in the mid-infrared band, a reflectivity of more than 80% in the near-infrared band, and a transmittance of more than 90% at 940nm.

9. The display film material according to claim 1, characterized in that: The materials and thicknesses of each layer in the spectral modulation layer are set as follows:

10. A method for preparing the display film material according to claim 1, characterized in that: TiO2 was used as the high-refractive-index material and SiO2 as the low-refractive-index material. Both TiO2 and SiO2 were deposited by electron beam evaporation deposition. The deposition temperature was selected as (100-150)℃, and the vacuum degree was set to 1*10. -3 ~1.5*10 -3 The energy of the SiO2 ion source flux is (170-200) V, (6-7) A, and the energy of the TiO2 ion source flux is (200-250) V, (7.5-8) A; the TiO2 particle size is 1-3 mm; the SiO2 material particle size is 1-3 mm.

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