Display film material and preparation method thereof

Abstract

The present invention relates to a display film material and a preparation method thereof. The display film material comprises a substrate and a light regulation layer disposed on the substrate. The substrate is an optically transparent material. The light regulation layer is formed by alternating a low-refractive index material and a high-refractive index material. The difference in refractive index between the low-refractive index material and the high-refractive index material is greater than 0.4. After light passes through the light regulation layer and the substrate, a visible light transmittance of over 90% and a near-infrared rejection rate of up to over 80% are achieved. Furthermore, the display film material has high transmittance at 940-1000nm and a mid-infrared emissivity of over 90%, ultimately achieving a cooling effect of 3-8 degrees Celsius.

Description

Technical Field

[0001] This invention relates to a film, and more particularly to a display film material and its preparation method. Background Technology

[0002] With global population growth and continuous social development, climate change is becoming increasingly severe, leading to a surge in demand for cooling energy. Traditional active cooling methods rely on compression-based cooling systems, which consume significant amounts of electricity and generate large amounts of carbon dioxide. Furthermore, the refrigerants used in these systems, such as Freon, deplete the ozone layer, causing serious environmental problems. Radiation cooling, significantly different from traditional methods, is a passive cooling approach that emits heat into the cold universe through thermal radiation. The Earth's atmosphere has varying transmittance for different wavelengths of electromagnetic waves, with extremely high transmittance in the 8-13 μm band, known as the "atmospheric window." Therefore, an excellent radiation cooling surface should have the highest possible emissivity in the 8-13 μm band while strongly reflecting sunlight (0.3-2.5 μm), thus achieving spontaneous cooling without consuming any energy. In conclusion, radiation cooling technology can save energy and mitigate the greenhouse effect and environmental pollution associated with traditional cooling methods.

[0003] With the development of nanophotonics and advanced manufacturing technologies, photonic crystals and metamaterials have been first applied to radiation cooling materials. Nanophotonic crystals refer to nanophotonic materials with various layered structures and metasurface structures formed by processing some semiconductor materials through coating processes such as magnetron sputtering and electron beam evaporation or micro-nano fabrication processes, thereby achieving selective high emission in specific mid-infrared bands.

[0004] Ordinary materials typically have broad radiation spectra, while photonic materials can be used to design a controllable, narrow-band emission spectrum heat source, which is particularly needed in radiative cooling. Currently, many nanostructured materials are being used in radiative cooling. However, radiative cooling materials are mostly used in outdoor construction such as walls and roofs, and less frequently in display devices. This is because display devices have higher requirements for the spectral properties of radiative cooling materials. Summary of the Invention

[0005] The purpose of this invention is to provide a radiation cooling film suitable for display devices, especially for display devices with integrated sensors. Based on this purpose, this invention provides a display film material that, through the design of the selected material and the design of the structure, satisfies the requirements of high visible transmittance, high near-infrared reflectivity, and high mid-infrared emissivity.

[0006] The technical solution adopted in this invention is as follows: a display film material, comprising a substrate and a light modulation layer disposed on the substrate, wherein the substrate has a visible light absorption rate of <5% in the 400-780nm range, preferably no absorption, and a transmittance of >90%, and a near-infrared light absorption rate of <5% in the 900-1100nm band, preferably no absorption, and can be an organic or inorganic material, and can be a flexible or rigid material, preferably a mixture of one or more materials selected from Glass, PET, PC, PMMA, PE, and COP. The light modulation layer is used to modulate the optical properties of the film material, compensate for the shortcomings of the substrate in terms of optical properties, and enhance the operability of the material. The light modulation layer is formed by the deposition of several organic and / or inorganic materials. After the light passes through the light modulation layer and the substrate, the transmittance in the visible light band of 400~780nm is greater than 80%, preferably greater than 90%, the emissivity in the mid-infrared band of 8~13μm is greater than 85%, preferably greater than 95%, the reflectivity in the near-infrared band of 900~1400nm is greater than 70%, and the transmittance in the 940~1100nm band is greater than 70%.

[0007] Preferably, the substrate has an absorption rate of less than 1% and a transmittance of greater than 90% in the 400-780nm wavelength range, and an absorption rate of less than 1% in the 900-1400nm 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 in the 400-780nm wavelength range is greater than 90%, the emissivity in the 8-13μm wavelength range is greater than 85%, the reflectivity in the 900-1400nm wavelength range is greater than 80%, and the transmittance in the 940-1000nm wavelength range is greater than 90%.

[0008] In this invention, the light modulation layer is formed by stacking at least two materials, and the refractive index difference between the two materials is greater than or equal to 0.4, preferably greater than or equal to 0.5, and even more preferably between 0.5 and 0.8. The material with the higher refractive index is referred to as the high-refractive-index material, and the material with the lower refractive index as the low-refractive-index material. The high-refractive-index material and the low-refractive-index material are stacked alternately. This alternating stacking of high and low refractive-index materials allows for interference, selective transmission, or reflection of light in different wavelength bands, thereby achieving spectral modulation. When the refractive index difference between the high-refractive-index material and the low-refractive-index material is greater than or equal to 0.4, admittance-matched interference of the multilayer film can be used to achieve a refractive index close to that of air (1) in the 400–780 nm and 940–1100 nm wavelength bands, thus achieving high transmission in these bands. In the 900–1400 nm band (excluding 940–1100 nm), the refractive index is far from that of air (∞), thus achieving high reflection in these bands.

[0009] The number of layers of the high-refractive-index material and the low-refractive-index material can be the same or different. The high-refractive-index material can also be one or more materials. Similarly, the low-refractive-index material can also be one or more materials. The present invention preferably has at least two layers of material in the thickness range of 25nm to 500nm. The refractive index difference between the two layers is 0.5 to 0.8. To explain in more detail, when the film layer is less than the preferred thickness, the processing will cause (1) poor film uniformity, poor cooling effect and sensor sensitivity, and even affect normal operation; (2) film layer stress imbalance, which cannot be offset by the stress of the adjacent layers, thus leading to film cracking, etc.; (3) the influence of error is amplified in the normal processing, thus making it impossible to accurately control the spectral deviation. When the film layer is greater than the preferred thickness, it is easy to cause problems such as excessive local film layer stress, excessive use of film material, poor appearance, and increased equipment failure rate. The refractive index difference between the two layers is preferably 0.5 to 0.8. This refractive index difference ensures sufficient refractive index difference to achieve excellent spectral control effect with fewer layers. It also helps to select more suitable materials for product processing. Furthermore, at this film thickness setting, a refractive index difference lower than this value will result in low near-infrared reflectivity, which will affect the cooling effect of radiative cooling.

[0010] The light modulation layer comprises multiple layers of low-refractive-index material and multiple layers of high-refractive-index material, with a preferred total number of 38-50 layers. Fewer layers would fail to coordinate the optical effects across different wavelengths, while a higher number would result in poor adhesion between the light modulation layer and the substrate, and also reduce light transmittance. Each low-refractive-index material and each high-refractive-index material is a metal oxide or non-metal oxide, and within a nanometer thickness range, the transmittance of each low-refractive-index material and each high-refractive-index material in the visible light band is higher than 90%. The low-refractive-index materials can be the same or different, and are preferably selected from one or more combinations of TiO2 (titanium oxide), Ti3O5 (titanium pentoxide), ZrO2 (zirconia), CeO2 (cesium oxide), HfO2 (hafnium oxide), Nb2O5 (niobium pentoxide), and Ta2O5 (tantalum pentoxide). The high-refractive-index materials can also be the same or different, and are preferably selected from one or more combinations of SiO2 (silicon dioxide), SiO (silicon monoxide), MgF2 (magnesium fluoride), Al2O3 (aluminum oxide), PRO4 (silicon-aluminum mixture), PRO6 (silicon-aluminum mixture), cryolite, and AlF3 (aluminum fluoride). The above-mentioned high-refractive-index materials do not absorb light in the spectral bands that need to be regulated, which is beneficial to enhancing the light regulation effect.

[0011] The thickness settings of high-refractive-index and low-refractive-index materials affect the light control effect of the material layer. In this invention, the preferred thickness value of the high-refractive-index material is 10~200nm, and the preferred thickness value of the low-refractive-index material is 20~300nm. With this thickness combination, on the one hand, the uniformity of the material layer can be guaranteed, on the other hand, the high film stress can be prevented, reducing the possibility of film cracking. Furthermore, it can sensitively distinguish beams of different wavelengths and control the path of each beam of different wavelengths, effectively distinguishing visible light, near-infrared light, and mid-infrared light. Moreover, based on light interference, the transmittance of the visible light band can be increased, and the reflectivity of the near-infrared band can be improved.

[0012] In this invention, the alternating layering of high-refractive-index and low-refractive-index materials is not limited to adjacent alternating layers. It can also consist of several layers of low-refractive-index materials followed by high-refractive-index materials, and then another layer of low-refractive-index materials. That is, the layering method 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 materials…. In the setting of method (2), the tunability of the wavelength band can be enhanced, so that light of different wavelength bands exhibits different optical properties.

[0013] The light-regulating layer in this invention can be directly deposited on the substrate, or a transition layer can be deposited on the substrate first. The presence of the transition layer helps to enhance the bonding stability between the light-regulating layer and the substrate. Preferably, the transition layer is an organic material, referred to as the first organic layer. SA, RA, SHA, phthalocyanine organic compounds are also preferred. SA, RA, and SHA are commercial organic materials manufactured by Ceko and NanoPrimer in South Korea. When SA, RA, SHA, and phthalocyanine organic compounds are used as the first organic layer, they have no light absorption in the visible light band, reducing the impact of the film layer on the transmittance of the visible light band, and have excellent impact resistance, thus improving the bonding stability between the substrate and the light-regulating layer. Above the light-regulating layer, i.e., on the side of the light-regulating layer facing away from the substrate, a second organic layer is disposed. The second organic layer is a hydrophobic and oleophobic organic material, preferably a fluorinated organic material, and more preferably AF (anti-fingerprint film). AF has extremely low surface energy, enabling self-cleaning. The second organic layer, on the one hand, makes the film material of this invention less susceptible to water or oil contamination during use, thus playing a self-cleaning role; on the other hand, AF has excellent spectral regulation performance. The preferred thickness of the AF layer is (10-40) nm. When the AF thickness is less than 10 nm, it is difficult to form a dense film on the surface, resulting in poor hydrophobicity. When it exceeds 40 nm, an oily layer will form on the surface, which cannot effectively bond with other film layers. Furthermore, an excessively thick film layer will cause material waste and surface changes.

[0014] The second organic layer needs to be deposited using a barrier evaporation process. The preferred current is (30-200) mA, and the deposition rate is (3-9) A / s. If the evaporation rate is too low, the AF material will lack kinetic energy, resulting in a thin film with poor density. If the evaporation rate is too high, the product will have poor uniformity.

[0015] As a preferred embodiment, the second organic layer is disposed on the substrate, specifically on the side of the substrate opposite to the light-controlling layer. During film application, the light-controlling layer contacts the display screen via AB adhesive, while the second organic layer remains on the surface. This configuration enhances the hydrophobic and abrasion-resistant properties of the AF material.

[0016] As a preferred embodiment, the high-refractive-index material in this invention is TiO2, and the low-refractive-index material is SiO2. The light-modulating layer consists of 41 layers of alternating TiO2 and SiO2 layers. The first organic layer is SHA, and the second organic layer is AF. The particle size of both the high-refractive-index and low-refractive-index materials is (1-3) mm. The production process is as follows:

[0017] The coating temperature of the light control layer is set to 100℃, and the vacuum degree is set to 1*10. -3 Pa. The energy of SiO2 ion source flux is 170V, 6A; the energy of TiO2 ion source flux is 200V, 8A; SHA is processed by EB (electron beam evaporation) with a current of 10-60mA; AF is processed by barrier evaporation with a heating current of 100-200mA.

[0018] Material layer Material Thickness (nm) Coating rate (A / s) Low refractive index materials SiO2 15-300 4-6 High refractive index materials <![CDATA[TiO2]]> 10-200 2-2.5 First organic layer SHA 80-150 3-8 Second organic layer AF 30nm 4-10

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

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

[0021] Material layer Material Thickness (nm) Coating rate (A / s) Low refractive index materials <![CDATA[SiO2&MgF2]]> 15-300 4-6 High refractive index materials <![CDATA[TiO2]]> 10-200 2-2.5 First organic layer SHA 80-150 3-8 Second organic layer AF 30nm 4-10

[0022] As a preferred embodiment, the high refractive index material in this invention is Ta₂O₅ (n=2.32@500 nm) and the low refractive index material is SiO₂ (n=1.46@550 nm). The total number of layers is 49, and the particle size of both the high and low refractive index materials is 1-3 mm. The first organic layer is SA, and the second organic layer is AF. The preparation process used is as follows:

[0023] The coating temperature is set to 100℃, and the vacuum degree is set to 1*10. -3 The energy of the SiO2 ion source flux is 170V and 6A; the energy of the Ta2O5 ion source flux is 200V and 8A; SA is processed using the EB method with a current of 10-60mA; AF is processed using the barrier vaporization process with a heating current of 100-200mA.

[0024] Material layer Material Thickness (nm) Coating rate (A / s) Low refractive index materials <![CDATA[SiO2]]> 15-300 4-6 High refractive index materials <![CDATA[Ta2O5]]> 10-200 2-2.5 First organic layer SA 80-150 3-8 Second organic layer AF 30nm 4-10

[0025] The beneficial effects of this invention include: the film controls the spectral performance of different bands through the multilayer film structure design, so that the film material in this invention has the following properties: (1) high near-infrared blocking performance, (2) does not affect the sensor sensing effect, (3) effectively blocks the incident of other energy in the solar light band, and (4) emits heat in the form of electromagnetic waves into the natural cold source of the universe through the thermal infrared band, so as to achieve the maximum radiation cooling effect.

[0026] In this invention, the film material is alternately set with high and low refractive indices. Utilizing the interference effect of light, the stacking of different materials increases the transmittance in the visible light band, the reflectance in the near-infrared band, and the emissivity in the mid-infrared band. Ultimately, it achieves a visible light transmittance of over 90%, a near-infrared blocking rate of over 80%, a mid-infrared emissivity of over 90%, and high transmittance of over 90% in the 940-1000nm band, resulting in a cooling effect of 3-8 degrees Celsius.

[0027] The membrane material in this invention can be adhered to almost any material surface for cooling, such as glass, walls, roofs, and displays of electronic devices, making it an effective tool for energy conservation and emission reduction. Adding an organic encapsulation layer to the surface of the membrane material gives the product excellent anti-aging properties, resulting in superior hydrophobic, antifouling, and wear-resistant performance during use.

[0028] When the film material of this invention is applied to display devices, especially flat panel displays such as mobile phones, the screen integrates a large number of sensors, such as fingerprint sensors, Face ID sensors, proximity sensors, ambient light sensors, and Time-of-Flight (TOF) sensors. The operating wavelengths of these sensors are mainly concentrated in the visible light or near-infrared bands (commonly 940nm). The film material of this invention can achieve high transmittance at 940nm, ensuring sensor sensitivity.

[0029] According to Planck's law of thermal radiation: B(λ, T) = (2hc² / λ) 5 B(λ, T) is the radiant energy density per unit area and per unit wavelength range, where λ is the wavelength, T is the absolute temperature, c is the speed of light, h is Planck's constant, and k is Boltzmann's constant. The operating temperature of products related to daily life is between 30-70℃, especially display devices, which typically operate between 30-60℃. Their main wavelength range for thermal radiation lies within the atmospheric window region. By attaching this invention to the screen cover glass of a display device, wide-spectrum modulation can be achieved to isolate solar thermal radiation, optimize the operating wavelength of optical sensors to avoid affecting their operation, and improve the product's thermal radiation capability in the 8-13μm atmospheric window band. Attached Figure Description

[0030] Figure 1 Structural diagram of the membrane material in Example 1;

[0031] Figure 2 Transmittance of the film before and after coating in Example 1;

[0032] Figure 3 The emissivity of the membrane material in Example 1;

[0033] Figure 4 Detection values ​​for monitor with and without screen protector, and ambient temperature;

[0034] Figure 5 Structural diagram of the membrane material in Example 2. Detailed Implementation

[0035] The present invention will be further explained in detail below with reference to the accompanying drawings and specific embodiments, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0036] Example 1

[0037] In this embodiment, the substrate of the film material is a commercial tempered glass screen protector for mobile phones. The high-refractive-index material in the light-modulating layer is TiO2 (n=2.35@500 nm), and the low-refractive-index material is SiO2 (n=1.46@550 nm). The light-modulating layer is obtained using an electron beam evaporation coating system and consists of 39 layers, arranged sequentially from closest to furthest from the substrate: TiO2 layer, SiO2 layer, TiO2 layer…SiO2 layer, TiO2 layer. The thickness and coating rate of each layer are shown in Table 1. The particle size of the high-refractive-index and low-refractive-index materials is selected as 1-3 mm. The organic layer uses SHA & AF. The structure of the film material is as follows: Figure 1As shown, the first organic layer is deposited on the substrate, and the second organic layer is deposited on the back side of the substrate. The numbers 1 / 2 / 3...n in the figure are the layer numbers of the light-modulating layer.

[0038] The coating temperature of the light control layer is 100℃, and the vacuum degree is 1*10. -3 The energy of the SiO2 ion source flux is 170V and 6A; the energy of the TiO2 ion source flux is 200V and 8A; SHA is processed using the EB method with a current of 10-60mA; AF is processed using the barrier vaporization process with a heating current of 100-200mA.

[0039] Table 1. Materials, thicknesses, and coating rates of each layer

[0040] Floor Material Thickness (nm) Rate (A / S) 1 SHA 100 8 2 TIO2 14.47 2.5 3 SIO2 28.57 6 4 TIO2 114.7 2.5 5 SIO2 36.54 6 6 TIO2 13 2.5 7 SIO2 99.42 6 8 TIO2 16.98 2.5 9 SIO2 30.36 6 10 TIO2 144.72 2.5 11 SIO2 25 6 12 TIO2 26.29 2.5 13 SIO2 192.99 6 14 TIO2 108.41 2.5 15 SIO2 184.96 6 16 TIO2 38.51 2.5 17 SIO2 28.88 6 18 TIO2 27.35 2.5 19 SIO2 373.2 6 20 TIO2 25.28 2.5 21 SIO2 33.09 6 22 TIO2 35.37 2.5 23 SIO2 186.66 6 24 TIO2 109.58 2.5 25 SIO2 194.07 6 26 TIO2 26.55 2.5 27 SIO2 25 6 28 TIO2 148.09 2.5 29 SIO2 32.22 6 30 TIO2 17.21 2.5 31 SIO2 112.23 6 32 TIO2 14.17 2.5 33 SIO2 37.89 6 34 TIO2 137.03 2.5 ·35 SIO2 25 6 36 TIO2 35.18 2.5 37（n-3） SIO2 40.65 6 38（n-2） TIO2 27.6 2.5 39（n-1） SIO2 50.02 6 40（n） TIO2 13 2.5 -1 AF 20 6

[0041] Tests were conducted on the original glass (commercial tempered glass screen protector) and the coated glass, respectively.

[0042] 1. The reflectivity of commercial glass and coated glass in the solar spectrum 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.

[0043] The reflectivity of glass before and after coating is as follows: Figure 2 As shown, the results indicate that after adding the radiation cooling film of the present invention, the transmittance of the glass in the near-infrared band is significantly reduced, from 90% of the original glass to about 30%.

[0044] 2. The emissivity of commercial glass and coated glass in the mid-infrared band was tested using a Fourier Transform Infrared (FT-IR) spectrometer (Nicolet IS50, ThermoFisher), an Integral Gazelle Sphere (IntergatIR MIR, Pike), and a mercury cadmium telluride detector. The emissivity of the glass before and after coating is shown below. Figure 3 As shown, the results indicate that after adding the radiation cooling film of the present invention, the emissivity of the glass in the mid- and far-infrared bands is significantly improved, especially in the atmospheric window (8-13 μm), from an average of less than 0.8 to more than 0.9.

[0045] 3. To test the cooling effect of commercial glass and coated glass, a temperature tester was placed in coated glass, original glass (attached to a commercial mobile phone under continuous operation with the screen on), and air. Temperature changes were recorded under all three conditions. Lower temperatures indicate better cooling performance. The instrument used was a K-type Omega thermocouple. Results are as follows: Figure 4As shown, under outdoor conditions with an ambient temperature of approximately 30°C, the coated glass can reduce the operating temperature of a mobile phone by 3-8°C, demonstrating a significant cooling effect.

[0046] 4. The hydrophobic properties of the coated glass were tested using a Theta contact angle tester (LSA100, LAUDAS Scientific). The average static contact angle was found to be over 115°, indicating excellent hydrophobic properties.

[0047] Example 2

[0048] In this embodiment, the substrate of the film material is tempered glass. The low-refractive-index material in the light-modulating layer is SiO2, and the high-refractive-index material is TiO2. The light-modulating layer is obtained using an electron beam evaporation coating system and consists of 36 layers. The particle size of the high-refractive-index and low-refractive-index materials is selected as 1-3 mm. The organic layer uses SHA & AF, and the structure after coating is as follows... Figure 5 As shown, the first organic layer is deposited between the light control layer and the glass substrate as a buffer transition layer, and the second organic layer is deposited on the light control layer.

[0049] The coating temperature was set to 150℃, and the vacuum degree was set to 1.5*10. -3 The energy of the SiO2 ion source flux is 200V and 7A; the energy of the TiO2 ion source flux is 250V and 7.5A; SHA is processed using the EB method with a current of 10-60mA; AF is processed using the resistance evaporation process with a heating current of 100-200mA.

[0050] Table 2. Materials, thicknesses, and coating rates of each layer

[0051] Floor Material Thickness (nm) Rate (A / S) 1 SHA 100 8 2 TIO2 14.08 2.5 3 SIO2 27.38 6 4 TIO2 112.05 2.5 5 SIO2 31.6 6 6 TIO2 17.57 2.5 7 SIO2 75.99 6 8 TIO2 18.9 2.5 9 SIO2 32.78 6 10 TIO2 141.74 2.5 11 SIO2 27 6 12 TIO2 25.11 2.5 13 SIO2 194.84 6 14 TIO2 109.22 2.5 15 SIO2 175.86 6 16 TIO2 117.77 2.5 17 SIO2 46.39 6 18 TIO2 12 2.5 19 SIO2 263.95 6 20 TIO2 25.19 2.5 21 SIO2 32.87 6 22 TIO2 35.99 2.5 23 SIO2 188.33 6 24 TIO2 110.48 2.5 25 SIO2 194.35 6 26 TIO2 25.65 2.5 27 SIO2 27 6 28 TIO2 151.49 2.5 29 SIO2 27 6 30 TIO2 21.93 2.5 31 SIO2 233.95 6 32 TIO2 14.75 2.5 33 SIO2 63.54 6 34（n-3） TIO2 27.16 2.5 35（n-2） SIO2 31.28 6 36（n-1） TIO2 123.53 2.5 37（n） SIO2 91.58 6 -1 AF 20 6

[0052] Tests were conducted on the original glass (commercial tempered glass screen protector) and the coated glass, respectively.

[0053] 1. The reflectivity of commercial glass and coated glass in the solar spectrum 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.

[0054] The reflectivity of the glass before and after coating shows that after adding the radiation cooling film of the present invention, the transmittance of the glass in the near-infrared band is significantly reduced, from 90% of the original glass to about 30%.

[0055] 2. The emissivity of commercial glass and coated glass in the mid-infrared band was tested using a Fourier transform infrared (FT-IR) spectrometer (Nicolet IS50, ThermoFisher), an IntergatIR MIR (Pike), and a mercury cadmium telluride detector. The emissivity results before and after coating show that the addition of the radiation-cooling film of this invention significantly improves the emissivity of the glass in the mid- and far-infrared bands, especially in the atmospheric window (8-13 μm), increasing from an average of less than 0.8 for the original glass to more than 0.9.

[0056] 3. Using a colorimeter (HC-CR8W), the reflectance of the glued screen on the processed product was tested, and the reflectance Y was approximately 1.8. The reflectance of the glued screen on the original glass was also tested, and the reflectance Y was approximately 5.3. The processed product exhibits significant anti-reflective and anti-glare properties.

[0057] 4. To test the cooling effect of commercial glass and coated glass, a temperature tester was placed in coated glass, original glass (attached to a commercial mobile phone under continuous operation with the screen on), and air. Temperature changes were recorded under all three conditions. Lower temperatures indicate better cooling performance. The instrument used was a K-type Omega thermocouple. In outdoor conditions with an ambient temperature of approximately 30℃, the coated glass reduced the mobile phone's operating temperature by 3-8℃, demonstrating a significant cooling effect.

[0058] 5. The hydrophobic properties of the coated glass were tested using a Theta contact angle tester (LSA100, LAUDAS Scientific). The average static contact angle was found to be over 115°, indicating excellent hydrophobic properties.

[0059] Example 3

[0060] In this embodiment, the substrate of the film material is tempered glass. The low-refractive-index material in the light-modulating layer is SiO2, and the high-refractive-index material is Ta2O5 (n=2.32@500 nm). The light-modulating layer is obtained by an electron beam evaporation coating system and consists of 39 layers. From the closest to the substrate to the farthest away from the substrate, the layers are Ta2O5, SiO2, Ta2O5, SiO2, ... Ta2O5, SiO2. The particle size of the high-refractive-index and low-refractive-index materials is selected as 1-3 mm. The first organic layer is made of SA, and the second organic layer is made of AF, which are particulate materials. The first organic layer is disposed between the light-modulating layer and the substrate material, and the second organic layer is disposed on the side of the light-modulating layer opposite to the first organic layer.

[0061] The coating temperature is set to 100℃, and the vacuum degree is set to 1*10. -3The energy of the SiO2 ion source flux is 170V and 6A; the energy of the Ta2O5 ion source flux is 200V and 8A; SA is processed using the EB method with a current of 10-60mA; AF is processed using the barrier vaporization process with a heating current of 100-200mA.

[0062] Table 3. Materials, thicknesses, and coating rates of each layer

[0063] Floor Material Thickness (nm) Rate (A / S) 1 SA 100 8 2 TA2O5 15.81 2.5 3 SIO2 28.57 6 4 TA2O5 125.35 2.5 5 SIO2 36.54 6 6 TA2O5 14.21 2.5 7 SIO2 99.42 6 8 TA2O5 18.56 2.5 9 SIO2 30.36 6 10 TA2O5 158.15 2.5 11 SIO2 25 6 12 TA2O5 28.74 2.5 13 SIO2 192.99 6 14 TA2O5 118.47 2.5 15 SIO2 184.96 6 16 TA2O5 42.08 2.5 17 SIO2 28.88 6 18 TA2O5 29.89 2.5 19 SIO2 373.2 6 20 TA2O5 27.63 2.5 21 SIO2 33.09 6 22 TA2O5 38.65 2.5 23 SIO2 186.66 6 24 TA2O5 119.76 2.5 25 SIO2 194.07 6 26 TA2O5 29.02 2.5 27 SIO2 25 6 28 TA2O5 161.84 2.5 29 SIO2 32.22 6 30 TA2O5 18.81 2.5 31 SIO2 112.23 6 32 TA2O5 15.49 2.5 33 SIO2 37.89 6 34 TA2O5 149.76 2.5 35 SIO2 25 6 36 TA2O5 38.44 2.5 37（n-3） SIO2 40.65 6 38（n-2） TA2O5 30.17 2.5 39（n-）1 SIO2 50.02 6 40（n） TA2O5 14.21 2.5 -1 AF 20 6

[0064] Tests were conducted on the original glass (commercial tempered glass screen protector) and the coated glass, respectively.

[0065] 1. The reflectivity of commercial glass and coated glass in the solar spectrum 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.

[0066] The reflectivity of the glass before and after coating shows that after adding the radiation cooling film of the present invention, the transmittance of the glass in the near-infrared band is significantly reduced, from 90% of the original glass to about 40%.

[0067] 2. The emissivity of commercial glass and coated glass in the mid-infrared band was tested using a Fourier transform infrared (FT-IR) spectrometer (Nicolet IS50, ThermoFisher), an IntergatIR MIR (Pike), and a mercury cadmium telluride detector. The emissivity of the glass before and after coating showed that adding the radiation-cooling film of this invention significantly improved the emissivity of the glass in the mid- and far-infrared bands, especially in the atmospheric window (8-13 μm), increasing from an average of less than 0.8 to over 0.9.

[0068] 3. To test the cooling effect of commercial glass and coated glass, a temperature tester was placed in the coated glass, the original glass (attached to the commercial mobile phone under continuous operation with the screen on), and air. Temperature changes were recorded under all three conditions. Lower temperatures indicate better cooling performance. The instrument used was a K-type Omega thermocouple. In outdoor conditions with an ambient temperature of approximately 30℃, the coated glass reduced the mobile phone's operating temperature by 3-6℃, demonstrating a significant cooling effect.

[0069] 4. The hydrophobic properties of the coated glass were tested using a Theta contact angle tester (LSA100, LAUDAS Scientific). The average static contact angle was found to be over 115°, indicating excellent hydrophobic properties.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A display film material, characterized in that: The device includes a substrate and a light-modulating 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-modulating layer is formed by alternating layers of low-refractive-index and high-refractive-index materials. The material layer of the light-modulating layer closest to the substrate is a high-refractive-index layer, and the refractive index difference between the low-refractive-index and high-refractive-index materials is greater than 0.

5. In any thickness range of 25 nm to 500 nm along the thickness direction of the light-modulating layer, at least two layers of materials with a refractive index difference of 0.5 to 0.8 are disposed on the substrate through a first organic layer, the first organic layer having a light absorptivity of less than 5% in the 400-780 nm wavelength range. A second organic layer is disposed on the side of the substrate opposite to the light modulation layer, or a second organic layer is disposed on the side of the light modulation layer opposite to the substrate; after light passes through the light modulation layer and the substrate, the transmittance in the 400~780nm band is greater than 80%, the emissivity in the 8~13μm band is greater than 85%, the reflectivity in the 900~1400nm band excluding the 940~1100nm band is greater than 70%, and the transmittance in the 940~1000nm band is greater than 80%; the display film material is used on display devices integrating sensors. The materials and thicknesses of each layer in the light modulation layer are selected from one of A, B, and C, wherein... A is ； B is ； C is 。 2. The display film material according to claim 1, characterized in that: The first organic layer is selected from one or more of SA, RA, SHA, and phthalocyanine organic compounds.

3. The display film material according to claim 1, characterized in that: The second organic layer satisfies one or more of the following combinations: —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 a barrier evaporation current range of (30-200) mA and a deposition rate of (3-9) A / s.

4. 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, and the light modulation layer is disposed on the side where the first organic layer is disposed; the first organic layer is SHA and the second organic layer is AF.

5. 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 excluding the 940-1100nm band, and a transmittance of more than 90% at 940nm.

6. A method for preparing the display film material according to claim 1, characterized in that: TiO2 is used as a high refractive index material and SiO2 is used as a low refractive index material. Both TiO2 and SiO2 are formed by electron beam evaporation deposition. The deposition temperature is (100~150)℃, the vacuum degree is 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 particle size of TiO2 is 1-3 mm. The particle size of SiO2 material is 1-3 mm.

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