Glass with spectral selectivity, window and optical design method

Abstract

The invention discloses glass with spectral selectivity, a window and an optical design method, and belongs to the technical field of glass. The glass with spectral selectivity comprises a radiation cooling layer, a photon structure regulation and control layer and a substrate which are sequentially arranged from the outer side to the inner side, the outer side is a heat energy incidence side, and the inner side is a side needing temperature control; the mid-infrared light emissivity of the radiation cooling layer is greater than or equal to 90%; the photonic structure regulation and control layer is designed based on an effective medium theory and optical topology transformation, and meets the following optical properties: the reflectivity to an ultraviolet band is greater than or equal to 80%, the transmittance to a visible light band is greater than or equal to 75%, and the reflectivity to a near-infrared band is greater than or equal to 80%. Independent and accurate management of ultraviolet, visible light and near-infrared bands can be achieved, meanwhile, the radiation cooling layer conducts active heat dissipation, and indoor temperature control balance is maintained.

Description

Technical Field

[0001] This application relates to the field of glass technology, and more particularly to a method for designing glass, windows, and optics with spectral selectivity. Background Technology

[0002] In architecture and transportation, windows, as a crucial interface connecting indoor spaces with the external environment, not only fulfill the basic functions of providing light and visibility but also play a key role in thermal management. With the continuous growth of global energy consumption, building energy consumption now accounts for over 40% of total global energy consumption, including heating, cooling, and lighting loads, with approximately 50% of energy loss occurring through windows. This is primarily because traditional glass used in windows has poor thermal management efficiency. Its single optical characteristic means that in summer, the near-infrared band of solar radiation significantly increases the indoor heat load, leading to increased air conditioning energy consumption; while in winter, the low insulation performance of traditional glass exacerbates heat loss. Therefore, developing a type of window glass that can achieve efficient thermal regulation while maintaining good visible light transmittance to maintain optimal indoor temperatures in buildings or vehicles and minimize energy consumption has become an important research direction for achieving building energy conservation and improving the comfort of living environments.

[0003] In recent years, passive radiative cooling technology has attracted widespread attention because it can dissipate heat into outer space through atmospheric transparent windows without external energy input. Combined with multi-band spectrally selectively modulated photonic structure design, it provides a new path for the development of high-performance energy-saving glass and windows. Currently, various spectrally modulated glasses have been proposed and applied in practical scenarios to improve the energy-saving capabilities of windows, mainly including radiative cooling windows. These technologies typically utilize transition metal oxides or noble metal nanoparticles to achieve selective reflection, absorption, or transmission of specific bands in the solar spectrum.

[0004] However, current radiative cooling glass still faces several key technological bottlenecks that need to be overcome. First, most structures lack the ability to precisely and independently control multiple solar spectral bands, often sacrificing visible light transmittance while blocking harmful near-infrared radiation, thus affecting indoor natural lighting. Second, existing structures have poor multi-band spectral modulation capabilities, insufficient for efficiently regulating indoor living temperature and reducing energy consumption. Finally, some materials shield ultraviolet light by absorption rather than reflection; the resulting localized temperature rise actually increases heat transfer into the room, weakening overall cooling efficiency and affecting living comfort. These problems collectively restrict the overall energy-saving performance of radiative cooling glass in real-world environments, especially making it difficult to maintain ideal room temperature stability under high-intensity sunlight conditions. Summary of the Invention

[0005] This application provides a spectrally selective glass, window, and optical design method that can solve the problem that existing glass lacks the ability to accurately and independently control multiple solar spectral bands or has poor multi-band spectral modulation capabilities, and shields ultraviolet light by absorption rather than reflection.

[0006] To achieve the above objectives, the technical solution of this invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide a spectrally selective glass, comprising a radiation cooling layer, a photonic structure modulation layer and a substrate arranged sequentially from the outside to the inside, wherein the outside is the heat energy incident side and the inside is the side requiring temperature control.

[0008] The mid-infrared light emissivity of the radiation cooling layer is ≥90%;

[0009] The photonic structure modulation layer is based on the effective medium theory and optical topological transformation design, and meets the following optical performance requirements: reflectivity ≥80% in the ultraviolet band, transmittance ≥75% in the visible band, and reflectivity ≥80% in the near-infrared band.

[0010] In conjunction with the first aspect, in one possible implementation, the material of the radiative cooling layer is selected from polydimethylsiloxane, polymethyl methacrylate, and poly(vinylidene fluoride-co-hexafluoropropylene).

[0011] In conjunction with the first aspect, in one possible implementation, the radiation cooling layer is physically bonded to the photonic structure modulation layer by lamination.

[0012] In conjunction with the first aspect, in one possible implementation, the photonic structure modulation layer includes at least one set of modulation sublayers;

[0013] Each group of control sublayers consists of a silver film, a titanium dioxide film, and a silicon dioxide film, arranged from the outside to the inside.

[0014] In conjunction with the first aspect, in one possible implementation, the silver film has a thickness of 10 nm, the titanium dioxide film has a thickness of 27 nm, and the silicon dioxide film has a thickness of 50 nm.

[0015] In conjunction with the first aspect, in one possible implementation, the photonic structure modulation layer includes two sets of modulation sublayers.

[0016] In conjunction with the first aspect, in one possible implementation, the substrate is quartz glass, and the substrate thickness is 1.1 cm.

[0017] Secondly, another embodiment of the present invention provides a window comprising the spectrally selective glass described above.

[0018] Thirdly, another embodiment of the present invention provides an optical design method for a photonic structure control layer, used to design the aforementioned photonic structure control layer, comprising the following steps:

[0019] S1: Based on the effective medium theory, by adjusting the duty cycle f of the metal layer thickness. m Given the dielectric constants of metals and dielectrics, calculate the effective dielectric constant ε in the x, y, and z directions. xx , ε yy , ε zz The calculation formula is:

[0020] In the formula, ε || ε is the horizontal component of the real part of the effective dielectric constant. ⊥ f is the perpendicular component of the real part of the effective dielectric constant. m ε represents the duty cycle of the metal layer thickness. m ε is the dielectric constant of the metal. d d is the dielectric constant of the dielectric. m d is the thickness of the metal layer. d The thickness of the dielectric layer;

[0021] S2: At the boundary wavelength of 380 nm between ultraviolet and visible light and the boundary wavelength of 780 nm between visible and near-infrared light, the effective dielectric constant ε is adjusted. xx , ε yy , ε zz The sign change enables the topological transformation of the isofrequency surface from a closed ellipsoid to an open hyperboloid;

[0022] S3: Determine the film thickness based on the topological transition point, so that the ultraviolet reflectivity is ≥80%, the visible light transmittance is ≥75%, and the near-infrared reflectivity is ≥80%.

[0023] In conjunction with the third aspect, in one possible implementation, the topological transformation in step S2 is achieved by satisfying the following conditions:

[0024] At a wavelength of 380 nm, ε zz The change from negative to positive results in high reflectivity in the ultraviolet band;

[0025] At a wavelength of 780 nm, ε zz The change from positive to negative results in high reflectivity in the near-infrared band.

[0026] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0027] The spectrally selective glass provided in this application has the following characteristics: First, a radiative cooling layer is located on the outer side where heat energy is incident. Its high emissivity (mid-infrared emissivity ≥90%) allows it to efficiently dissipate accumulated heat from the room in the form of mid-infrared radiation, achieving a passive cooling effect. Second, a photonic structure control layer is placed between the radiative cooling layer and the substrate. Based on the effective medium theory and optical topological transformation design, it achieves abrupt changes in optical performance in specific wavelength bands: In the ultraviolet band (380nm and below), the layer triggers a topological transformation through a change in the dielectric constant, resulting in a reflectivity ≥80%, effectively shielding ultraviolet rays; in the visible light band (380-780nm), the topological transformation transforms into a closed ellipsoidal iso-frequency surface, maintaining a transmittance ≥75%, ensuring sufficient natural light intake; in the near-infrared band (above 780nm), the topological transformation occurs again, and the iso-frequency surface forms an open hyperboloid, achieving a reflectivity ≥80%, blocking heat input. Finally, the substrate, as a support layer, is located on the inner side where temperature control is required, enhancing the overall structural stability. The entire operation requires no external energy input. When heat is injected from the outside, the three layers work together to achieve independent and precise management of the ultraviolet, visible, and near-infrared bands. Simultaneously, the radiative cooling layer actively dissipates heat, maintaining indoor temperature balance. The glass provided in this application, through the design of the photonic structure control layer, achieves precise and independent control of the ultraviolet, visible, and near-infrared bands, solving the problem of poor multi-band spectral modulation capabilities in existing technologies: high reflectivity (≥80%) in the ultraviolet band avoids localized temperature rise and increased heat conduction caused by absorption-type shielding, significantly reducing indoor thermal gain; high transmittance (≥75%) in the visible band maintains high light transmittance while blocking harmful radiation, overcoming the defect of traditional structures sacrificing visible light transmittance; high reflectivity (≥80%) in the near-infrared band effectively blocks solar heat input, reducing summer cooling energy consumption. Furthermore, the high mid-infrared emissivity (≥90%) of the radiative cooling layer, combined with the substrate structure, achieves zero-energy active cooling, solving the problems of poor insulation performance and increased heat loss in winter, significantly improving overall energy efficiency. Finally, the integrated design of the three-layer structure optimizes thermal management performance, maintains room temperature stability under high-intensity sunlight, and solves the technical bottleneck of insufficient overall energy-saving performance of existing radiant cooling windows, providing an efficient solution for energy-saving applications in the building and transportation sectors. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of a spectrally selective glass provided in an embodiment of this application;

[0030] Figure 2 A diagram illustrating the mechanism of action of the spectrally selective glass provided in Embodiment 1 of this application in a window and the ordinary glass in Comparative Example 1 in a window in terms of thermal insulation.

[0031] Figure 3 The transmittance and reflectance curves of the spectrally selective glass provided in the embodiments of this application in the solar spectrum;

[0032] Figure 4 Electric field diagrams of spectrally selective glass provided for embodiments of this application at different wavelengths: (a) 380 nm; (b) 530 nm; (c) 1000 nm; (d) 2500 nm;

[0033] Figure 5 Physical models of radiative cooling effects for spectrally selective glass simulation applications provided for embodiments of this application: (a) an open cavity box; (b) a box with a glass cover; (c) a view of the cavity;

[0034] Figure 6 (a) is a graph showing the change of outdoor temperature and time throughout the year in a certain city; (b) is a graph showing the change of solar radiation intensity and time on a certain day in a certain city; and (c) is a graph showing the change of ambient temperature and time on a certain day in a certain city.

[0035] Figure 7 The temperature and time variation curves under simulated all-weather solar environmental conditions are shown in the embodiment of this application, after the spectrally selective glass and ordinary glass are installed in an open cavity box.

[0036] Icons: 1-Radiative cooling layer; 2-Photonic structure control layer; 21-Control sublayer; 211-Silver film; 212-Titanium dioxide film; 213-Silicon dioxide film; 3-Substrate. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of the embodiments of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0039] A spectrally selective glass includes a radiation cooling layer 1, a photonic structure modulation layer 2, and a substrate 3 arranged sequentially from the outside to the inside. The outside is the heat energy incident side, and the inside is the side requiring temperature control.

[0040] The mid-infrared emissivity of the radiative cooling layer 1 is ≥90%. The high emissivity in the mid-infrared band of the radiative cooling layer 1 allows for indoor cooling. The photonic structure modulation layer 2, based on effective medium theory and optical topological transformation design, meets the following optical performance requirements: reflectivity ≥80% in the ultraviolet band, transmittance ≥75% in the visible light band, and reflectivity ≥80% in the near-infrared band, enabling modulation of ultraviolet, visible, and near-infrared light bands.

[0041] The spectrally selective glass provided in this application has the following characteristics: First, the radiative cooling layer 1 is located on the outer side where heat energy is incident. Its high emissivity (mid-infrared emissivity ≥90%) allows it to efficiently dissipate accumulated heat from the room in the form of mid-infrared radiation, achieving a passive cooling effect. Second, the photonic structure control layer 2 is placed between the radiative cooling layer 1 and the substrate 3. Based on the effective medium theory and optical topological transformation design, it achieves abrupt changes in optical performance in specific wavelength bands: In the ultraviolet band (380nm and below), this layer triggers a topological transformation through a change in the dielectric constant, resulting in a reflectivity ≥80%, effectively shielding ultraviolet rays; in the visible light band (380-780nm), the topological transformation transforms into a closed ellipsoidal iso-frequency surface, maintaining a transmittance ≥75%, ensuring sufficient natural light intake; in the near-infrared band (above 780nm), the topological transformation occurs again, and the iso-frequency surface forms an open hyperboloid, achieving a reflectivity ≥80%, blocking heat input. Finally, the substrate 3, as a support layer, is located on the inner side where temperature control is required, enhancing the overall structural stability. The entire operation requires no external energy input. When heat is injected from the outside, the three layers work together to achieve independent and precise management of the ultraviolet, visible, and near-infrared bands. At the same time, the radiative cooling layer 1 actively dissipates heat to maintain indoor temperature balance. The glass provided in this embodiment achieves precise and independent control of the ultraviolet, visible, and near-infrared bands through the design of the photonic structure control layer 2, solving the problem of poor multi-band spectral modulation capability in the prior art: the high reflectivity (≥80%) in the ultraviolet band avoids the local temperature rise and increased heat conduction caused by absorption shielding, significantly reducing indoor heat gain; the high transmittance (≥75%) in the visible band maintains high light transmittance while blocking harmful radiation, overcoming the defect of traditional structures sacrificing visible light transmittance; the high reflectivity (≥80%) in the near-infrared band effectively blocks solar heat input, reducing cooling energy consumption in summer. In addition, the high mid-infrared emissivity (≥90%) of the radiative cooling layer 1, combined with the substrate 3 structure, achieves zero-energy active cooling, solving the problems of poor insulation performance and increased heat loss in winter, and significantly improving overall energy efficiency. Finally, the integrated design of the three-layer structure optimizes thermal management performance, maintains room temperature stability under high-intensity sunlight, and solves the technical bottleneck of insufficient overall energy-saving performance of existing radiant cooling windows, providing an efficient solution for energy-saving applications in the building and transportation sectors.

[0042] The material of radiative cooling layer 1 is selected from polydimethylsiloxane (PDMS), polymethyl methacrylate, and poly(vinylidene fluoride-co-hexafluoropropylene). These materials have high chemical stability and excellent optical properties, especially an emissivity of ≥90% in the mid-infrared band, which can efficiently convert indoor heat into radiant energy and dissipate it to the outer space, thus enhancing the passive radiative cooling capability of the glass. For example, PDMS, as a common polymer, is not only inexpensive and easy to process, but also maintains high emissivity at a thickness of micrometers, ensuring that the cooling effect does not cause local temperature rise due to material absorption. This material selection solves the problem of reduced cooling efficiency caused by improper material selection in traditional radiative cooling glass, improves overall thermal management performance, and supports environmentally friendly manufacturing processes.

[0043] Furthermore, the thickness of the radiation cooling layer 1 is on the micrometer level, for example 200 μm, to achieve good emissivity.

[0044] Furthermore, the radiative cooling layer 1 is physically bonded to the photonic structure modulation layer 2 via lamination. This bonding method avoids optical losses or thermal conduction problems that may be introduced by chemical adhesives, ensuring the stability and durability of the interlayer interface. Physical bonding simplifies the manufacturing process, reduces production complexity, and facilitates large-scale industrial production. Simultaneously, this method maintains the high emissivity of the radiative cooling layer 1, preventing spectral performance degradation due to interface defects. This design improves the overall reliability of the glass, solves the performance fluctuation problem caused by weak interlayer bonding in existing technologies, and ensures that the optical properties of ultraviolet reflection, visible light transmission, and near-infrared reflection remain consistent over long-term use.

[0045] The photonic structure modulation layer 2 includes at least one set of modulation sublayers 21, each set consisting of a silver film 211, a titanium dioxide film 212, and a silicon dioxide film 213, arranged sequentially from the outside to the inside. This multilayer nanostructure, based on the effective medium theory and the principle of optical topological transition, precisely achieves performance of ≥80% reflectivity in the ultraviolet band, ≥75% transmittance in the visible light band, and ≥80% reflectivity in the near-infrared band. The silver film 211 provides high reflectivity, while the titanium dioxide and silicon dioxide films 213 act as dielectrics to adjust the dielectric constant, jointly facilitating an optical topological transition at wavelengths of 380nm and 780nm, causing a sudden change in electromagnetic wave propagation characteristics, thereby efficiently reflecting ultraviolet and near-infrared light while maintaining high transmittance of visible light. This structural design solves the problem of not being able to simultaneously optimize multiple bands in existing technologies, avoids the thermal gain caused by absorptive ultraviolet shielding, and significantly improves energy-saving performance.

[0046] Furthermore, the thicknesses of the silver film 211, titanium dioxide film 212, and silicon dioxide film 213 are all in the nanometer range. Even further, the thickness of the silver film 211 is 10 nm, the titanium dioxide film 212 is 27 nm, and the silicon dioxide film 213 is 50 nm. This achieves an optical topological transition at the boundary wavelength of 380 nm between ultraviolet and visible light, and at the boundary wavelength of 780 nm between visible and near-infrared light, resulting in abrupt changes in transmittance and reflectance. These nanometer-scale thickness parameters are the result of optical calculation optimization, ensuring that the effective dielectric constant changes sign at the boundary wavelength of 380 nm between ultraviolet and visible light, and at the boundary wavelength of 780 nm between visible and near-infrared light, triggering a topological transition of the isofrequency surface from a closed ellipsoid to an open hyperboloid. This precise control achieves abrupt changes in reflectance and transmittance (such as a sharp increase in reflectance at 780 nm), avoiding performance deviations caused by excessively thick or thin films. Thickness optimization enhances spectral selectivity, ensuring the synergistic effect of high ultraviolet reflectance, high visible light transmittance, and high near-infrared reflectance, solving the problem of insufficient or excessive control, and improving the overall energy efficiency of the glass.

[0047] If there are too many control sublayers 21, the transmittance of visible light will decrease. Using only one set of control sublayers 21 results in poor reflection in the ultraviolet and near-infrared bands. Preferably, the photonic structure control layer 2 includes two sets of control sublayers 21 to achieve optimal spectral control performance, enhance the superposition effect of multilayer films, and further optimize the indicators of ultraviolet reflectance ≥80%, visible light transmittance ≥75%, and near-infrared reflectance ≥80%. For example, the two sets of sublayers enhance optical interference, improve the reflection efficiency of ultraviolet and near-infrared light, and maintain high visible light transmittance, thus solving the problem of limited control capability of a single structure.

[0048] The substrate 3 is made of quartz glass. Preferably, the thickness of the substrate 3 is 1.1 cm. Quartz glass has high transparency and excellent mechanical strength, ensuring high transmittance (≥75%) in the visible light band, while enhancing the overall durability of the glass. The thickness of 1.1 cm is a result of careful consideration: too thin (below 1.1 cm) can lead to increased brittleness and a higher risk of breakage; too thick (above 1.1 cm) would reduce visible light transmittance and affect the lighting effect. The 1.1 cm thickness of the substrate 3 balances the issues of transmittance loss and structural fragility, providing stable support for the radiation cooling layer 1 and the photon structure modulation layer 2, thus improving the practicality and service life of the glass.

[0049] The spectrally selective glass provided in this application achieves excellent multispectral modulation performance and radiative cooling capability through precise control of the ultraviolet-visible-near-infrared bands via different functional layers. This allows for maintaining good light transmittance on the temperature-controlled side while also meeting thermal management requirements. The core innovation of this glass lies in its photonic structure modulation layer 2: it exhibits high transmittance in the visible light band to maintain high transparency and thus good indoor light transmittance; it maintains high reflectivity in the near-infrared band to block additional thermal radiation energy; and it employs a high-reflectivity rather than high-absorption design in the ultraviolet band to effectively reduce indoor thermal gain. Simultaneously, this material can spontaneously radiate heat outwards through the mid-infrared band without external power or heating, achieving zero-energy thermal management. This design satisfies indoor thermal regulation requirements while also considering light transmittance. Furthermore, this glass exhibits precise control, high efficiency, and zero energy consumption, and its innovative design provides a new approach to reducing energy consumption in building or automotive interiors. This technology can be fabricated using currently commercially available magnetron sputtering technology, possessing large-scale production capabilities and promising commercial prospects.

[0050] Another embodiment of the present invention provides a window comprising the above-described spectrally selective glass.

[0051] In practice, abrupt control of reflection and transmission at different wavelengths can be achieved through the epsilon-near-zero (ENZ) region of the material, in which the horizontal component of the real part of the dielectric constant ε... || The sign of one component changes from positive to negative. For example, when a material is irradiated with light of wavelength λ, if its dielectric constant is close to zero, then that wavelength is located in the ENZ region of the material. Therefore, by designing a structure to tune the equivalent zero-dispersion region near a specific wavelength band, precise control of transmission and reflection in the ultraviolet, visible, and near-infrared bands can be achieved.

[0052] In order to achieve abrupt changes in transmittance and reflectance of the thin film in a specific solar spectral band, it is necessary to perform nanoscale calculations on the metal layer (silver film 211) and the dielectric layer (titanium dioxide film 212 and silicon dioxide film 213) based on the effective medium theory.

[0053] Another embodiment of the present invention provides an optical design method for a photonic structure control layer 2, used to design the aforementioned photonic structure control layer 2, comprising the following steps:

[0054] According to the effective dielectric theory, the effective dielectric constant of the interface (ε) eff ) can be represented as:

[0055]

[0056] S1: Based on the effective medium theory, by adjusting the duty cycle f of the metal layer thickness.m Given the dielectric constants of metals and dielectrics, calculate the effective dielectric constant ε in the x, y, and z directions. xx , ε yy , ε zz The calculation formula is:

[0057] ,

[0058] In the formula, ε || ε is the horizontal component of the real part of the effective dielectric constant. ⊥ f is the perpendicular component of the real part of the effective dielectric constant. m ε represents the duty cycle of the metal layer thickness. m ε is the dielectric constant of the metal. d d is the dielectric constant of the dielectric. m d is the thickness of the metal layer. d The thickness of the dielectric layer.

[0059] S2: At the boundary wavelength of 380 nm between ultraviolet and visible light and the boundary wavelength of 780 nm between visible and near-infrared light, the effective dielectric constant ε is adjusted. xx , ε yy , ε zz The sign change enables the topological transformation of the isofrequency surface from a closed ellipsoid to an open hyperboloid, thereby significantly altering the propagation characteristics of electromagnetic waves.

[0060] Specifically, when a transverse wave (TM wave) is incident on the medium, the isofrequency surface formula of the hyperbolic metamaterial is expressed as:

[0061] ,

[0062] In the formula, k x k y and k z These are the components of the wave vector in the x, y, and z directions, respectively, and ε || ε is the horizontal component of the real part of the effective dielectric constant. ⊥ Let ω be the perpendicular component of the real part of the effective dielectric constant, and let c be the angular frequency and propagation speed of the light wave in vacuum, respectively.

[0063] Using the formula for isofrequency surfaces, when ε xx =ε yy =ε zz When ε = 0, the corresponding isofrequency surface is a closed ellipsoid, but when ε xx >0 and ε yy =ε zzWhen the frequency is less than 0, the isofrequency surface becomes an open hyperboloid. That is, near the ENZ wavelength, it changes from positive to negative, significantly altering the propagation characteristics of electromagnetic waves and causing abrupt changes in light transmission and reflection intensity. Specifically, at the boundary wavelength of 380nm between ultraviolet and visible light, and at the boundary wavelength of 780nm between visible and near-infrared light, an optical topological transformation occurs, resulting in abrupt changes in transmittance and reflectance. Corresponding to the photonic structure modulation layer 2, the silver film 211 has a thickness of 10nm, the titanium dioxide film 212 has a thickness of 27nm, and the silicon dioxide film 213 has a thickness of 50nm. The two sets of modulation sublayers 21 are arranged alternately to achieve the optimal spectral modulation effect.

[0064] like Figure 3 As shown in the figure, the leftmost starting point of the horizontal axis is 300nm, and the band from the left starting point to the left boundary of the blue box area is 380nm. The interval between 300nm and 380nm is the ultraviolet band. The band within the blue box area is 380nm to 780nm, which is the visible light band. The right boundary of the blue box area is 780nm, and the interval between 780nm and 2500nm is the near-infrared band. The black curve represents transmittance, and the red curve represents reflectance. Within the visible light band in the blue area, the reflectance and transmittance curves combine to form a closed ellipsoid, indicating high transmittance and low reflectance in the visible light band. To the right of the 780nm band, in the near-infrared band, it forms an open hyperboloid, indicating high reflectance and low transmittance in the ultraviolet band.

[0065] S3: Determine the film thickness based on the topological transition point, so that the ultraviolet reflectivity is ≥80%, the visible light transmittance is ≥75%, and the near-infrared reflectivity is ≥80%.

[0066] The optical design method for the photonic structure control layer 2 provided in this invention systematically establishes the mathematical relationship between the metal / dielectric nanolayer structure and the equivalent dielectric constant through effective dielectric theory (step S1), providing a theoretical calculation basis for multilayer film design. Step S2 introduces the concept of optical topological transformation, innovatively manipulating the equivalent dielectric constant component (ε) at two key spectral boundaries: ultraviolet-visible light (380 nm) and visible-near-infrared light (780 nm). xx , ε yy , ε zzThe sign change of the isofrequency surface (i.e., the topological transformation from a closed ellipsoid to an open hyperboloid) fundamentally alters the propagation characteristics of electromagnetic waves. This transformation is the physical root cause of the leap in optical performance at specific wavelengths. Step S3 directly correlates the topological transformation point with specific film thickness parameters, ensuring that the design results meet the stringent performance indicators of high ultraviolet reflectivity (≥80%), high visible light transmittance (≥75%), and high near-infrared reflectivity (≥80%). The entire method, from theoretical modeling to physical mechanisms to engineering parameters, forms a closed-loop design process, significantly improving the scientific rigor, accuracy, and predictability of the photonic structure control layer 2 design.

[0067] Furthermore, the topological transformation in step S2 above is achieved by satisfying the following conditions:

[0068] At a wavelength of 380 nm, ε zz The change from negative to positive results in high reflectivity in the ultraviolet band;

[0069] At a wavelength of 780 nm, ε zz The change from positive to negative results in high reflectivity in the near-infrared band.

[0070] ε at 380 nm wavelength zz The shift from negative to positive is a key condition for inducing high reflectivity in the ultraviolet band; and achieving ε at a wavelength of 780 nm is crucial. zz The change from positive to negative is the decisive factor triggering high reflectivity in the near-infrared band. This affects the dielectric constant component ε. zz The precise positioning and manipulation of sign changes reveal the intrinsic physical principle of how optical topological transformations modulate reflectivity at specific wavelengths. It clearly explains the physical nature of abrupt changes in spectral performance at the microscopic level of dielectric constant variation, enabling the design objective (high reflectivity / high transmittance) to be aligned with the underlying physical parameters (ε). zz The symbolic change established a direct and clear causal relationship.

[0071] The technical solution of this application will be further described below with reference to specific embodiments.

[0072] Example 1

[0073] Embodiment 1 of this application provides a spectrally selective glass, comprising a radiative cooling layer 1, a photonic structure modulation layer 2, and a substrate 3, arranged sequentially from the outside to the inside. The mid-infrared emissivity of the radiative cooling layer 1 is ≥90%. The photonic structure modulation layer 2, based on effective medium theory and optical topological transformation design, meets the following optical properties: reflectivity of 82.3% in the ultraviolet band (300-380 nm), transmittance of 78.4% in the visible light band (380-780 nm), and reflectivity of 85.7% in the near-infrared band (780-2500 nm).

[0074] Comparative Example 1

[0075] A traditional single-pane window is provided.

[0076] like Figure 2 As shown, traditional single-pane windows, lacking solar spectral selectivity, result in full-spectrum transmission, significantly increasing indoor thermal gain and hindering effective cooling. In contrast, the spectrally selective glass provided in Embodiment 1 of this application solves this problem through precise regional control of the ultraviolet-visible-near-infrared bands: its high reflectivity design in the ultraviolet band reduces heat load, its high transmittance in the visible band maintains indoor lighting, and its high reflectivity in the near-infrared band effectively blocks heat radiation. This structure significantly reduces the amount of light entering the room, improves the residential thermal environment, and achieves radiative cooling. The core difference from Comparative Example 1 is that Embodiment 1 implements the aforementioned spectral selectivity control mechanism, thereby optimizing thermal management performance. Figure 2 The high reflectivity in the ultraviolet / near-infrared band and the high transmittance in the visible light band of this glass were further verified, confirming its precise spectral control capability of high ultraviolet reflectivity, high visible light transmittance, and high near-infrared reflectivity. This radiation-cooled window, with its excellent spectral selectivity and thermal management performance, can be fabricated on a large scale using commercial technologies such as magnetron sputtering.

[0077] To characterize the zero-energy thermal management performance of the spectrally selective glass of Example 1, radiation cooling simulation was performed using COMSOL Multiphysics software. The test model was a 10×10×2 cm³ open cavity box. Figure 5 (a), (b), (c)), the outer layer is sealed with aluminum foil tape, and the openings are respectively covered with the glass of Example 1 and the conventional single-layer glass of Comparative Example 1. The solar radiation data are the measured values ​​of a certain city. Figure 6 The simulation results show that () Figure 7 Before 6:00 AM, when solar irradiance is low, the cavity temperature changes of Example 1 and Comparative Example 1 are similar and both are lower than the ambient temperature, due to the inherent mid-infrared radiation cooling capability of traditional glass. During the period of enhanced light intensity from 6:00 AM to 8:00 PM, the cavity temperature rises significantly under external thermal radiation, far exceeding the ambient temperature. When the irradiance reaches its peak, the cavity temperature of Comparative Example 1 rises to 90°C, while that of Example 1 is only 70°C, with a maximum temperature difference of 20°C. After 4:30 PM, the temperature difference between the two narrows due to the weakening of incident light caused by the increased solar tilt angle. These results fully demonstrate that Example 1 can achieve effective cavity cooling without external energy input, and its thermal management performance is significantly better than that of traditional glass.

[0078] Figure 3The spectral selectivity modulation mechanism of the glass in Example 1 was revealed: at 0.78 μm (780 nm) (right boundary of the blue region), the transmittance curve (black) drops sharply while the reflectance curve (red) rises simultaneously, forming a clear intersection, marking the activation of the near-infrared shielding effect. In the visible light band (380-780 nm), a completely opposite trend is observed: reflectance remains low while transmittance remains high, ensuring high light transmittance while blocking near-infrared radiation. In the ultraviolet band (0.3-0.38 μm, 300-380 nm) (left blank narrow band of the blue region), the reflectance peak reaches 0.86, achieving highly efficient ultraviolet reflection. Figure 4 Further refining this characteristic: low reflectivity and high transmittance at 380nm; optimal transmittance in the visible light center band at 530nm; and significantly improved near-infrared reflectivity from 1000nm, maintaining high reflectivity up to 2500nm. This precise spectral tuning of high ultraviolet reflectivity, high visible light transmittance, and high near-infrared reflectivity is the core foundation for achieving radiative cooling.

[0079] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0080] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A glass with spectral selectivity, characterized in that, It includes a radiation cooling layer, a photonic structure control layer and a substrate arranged sequentially from the outside to the inside, wherein the outside is the heat energy incident side and the inside is the side that needs temperature control; The mid-infrared light emissivity of the radiation cooling layer is ≥90%; The photonic structure modulation layer is based on the effective medium theory and optical topological transformation design, and meets the following optical performance requirements: reflectivity ≥80% in the ultraviolet band, transmittance ≥75% in the visible band, and reflectivity ≥80% in the near-infrared band.

2. The spectrally selective glass according to claim 1, characterized in that, The material of the radiation cooling layer is selected from one of polydimethylsiloxane, polymethyl methacrylate, and poly(vinylidene fluoride-co-hexafluoropropylene).

3. The spectrally selective glass according to claim 1, characterized in that, The radiation cooling layer is physically bonded to the photonic structure modulation layer through lamination.

4. The spectrally selective glass according to claim 1, characterized in that, The photonic structure modulation layer includes at least one set of modulation sublayers; Each group of control sublayers consists of a silver film, a titanium dioxide film, and a silicon dioxide film, arranged from the outside to the inside.

5. The spectrally selective glass according to claim 4, characterized in that, The silver film has a thickness of 10 nm, the titanium dioxide film has a thickness of 27 nm, and the silicon dioxide film has a thickness of 50 nm.

6. The spectrally selective glass according to claim 4 or 5, characterized in that, The photonic structure modulation layer includes two sets of modulation sublayers.

7. The spectrally selective glass according to claim 1, characterized in that, The substrate is quartz glass, and the substrate thickness is 1.1 cm.

8. A window, characterized in that, Includes the spectrally selective glass as described in any one of claims 1 to 7.

9. An optical design method for a photonic structure control layer, characterized in that, The method for designing the photonic structure modulation layer according to claims 1-7 includes the following steps: S1: based on the effective medium theory, by adjusting the metal layer thickness duty cycle f m and the dielectric constant of metal, dielectric, the effective dielectric constant ε of x, y, z direction xx , ε yy , ε zz , the formula is: In the formula, ε || ε is the horizontal component of the real part of the effective dielectric constant. ⊥ f is the perpendicular component of the real part of the effective dielectric constant. m ε represents the duty cycle of the metal layer thickness. m ε is the dielectric constant of the metal. d d is the dielectric constant of the dielectric. m d is the thickness of the metal layer. d The thickness of the dielectric layer; S2: At the boundary wavelength of 380 nm between ultraviolet and visible light and the boundary wavelength of 780 nm between visible and near-infrared light, the effective dielectric constant ε is adjusted. xx , ε yy , ε zz The sign change enables the topological transformation of the isofrequency surface from a closed ellipsoid to an open hyperboloid; S3: Determine the film thickness based on the topological transition point, so that the ultraviolet reflectivity is ≥80%, the visible light transmittance is ≥75%, and the near-infrared reflectivity is ≥80%.

10. The optical design method for the photonic structure modulation layer according to claim 9, characterized in that, The topological transformation in step S2 is achieved by satisfying the following conditions: At a wavelength of 380 nm, ε zz The change from negative to positive results in high reflectivity in the ultraviolet band; At a wavelength of 780 nm, ε zz The change from positive to negative results in high reflectivity in the near-infrared band.

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