Mechanically reversible dual-mode glass for energy conservation

Abstract

A dual mode glass for a window includes a glass substrate having a first side and a second side, a first member disposed on the first side of the glass substrate, and a second member disposed on the second side of the glass substrate. Wherein the first component and the second component are configured to enable the dual-mode glass to present a first transmissivity / emissivity mode for light rays incident on the first side and to present a second transmissivity / emissivity mode for light rays incident on the second side. The dual-mode glass is extremely suitable for different weather conditions due to different spectral characteristics on the two sides so as to maintain indoor comfort.

Description

Technical Field

[0001] This invention relates to glass windows, and in particular to windows that provide a variety of reflection or transmission modes. Background Technology

[0002] Smart glass has extremely broad application prospects. The latest smart glass market report shows that the global smart glass market size has been approximately US$4.5 billion to US$6.6 billion in recent years, with a compound annual growth rate of 10%, and is projected to reach US$23.34 billion by 2032. This growth is mainly driven by the continued increase in demand for energy-saving solutions in high-end commercial office and residential spaces. Smart glass manufacturers are actively investing in research and development, adopting new technologies and low-cost raw materials to reduce production costs.

[0003] The demand for smart windows in commercial buildings is growing rapidly, especially in the field of energy-efficient and environmentally friendly building design. By regulating light and heat conduction, smart windows can significantly reduce the energy consumption of air conditioning and heating systems, thereby improving energy efficiency and indoor comfort. The automotive industry is another important application area for smart windows, improving vehicle energy efficiency and passenger comfort. By suppressing heat buildup inside the vehicle and regulating visible light transmittance, smart windows optimize energy use and enhance the passenger experience. Furthermore, smart windows also have a promising future in the residential market. As people's pursuit of a higher quality living environment increases, smart windows can provide better light management and privacy protection while reducing energy consumption, meeting the environmental and energy-saving needs of modern families. Smart windows have broad application prospects in multiple industries, including construction, automotive, aerospace, and residential, significantly improving energy efficiency and user comfort. These characteristics give smart windows enormous growth potential in the future market.

[0004] Studies have shown that the human eye can only perceive light with wavelengths from 360nm-400nm to 830nm; light outside this range is called infrared or ultraviolet radiation. In the sunlight frequency band, visible light accounts for approximately 40-45% of the total energy, ultraviolet radiation for about 10%, and infrared radiation for about 45-50%. In the field of smart windows, especially for windows used in subtropical / tropical regions, it is essential to block infrared and ultraviolet radiation to prevent excess radiant energy from heating the indoor space. Therefore, a series of optical structures need to be designed to enable smart windows to achieve the aforementioned spectral performance. Summary of the Invention

[0005] According to a first aspect of this disclosure, a dual-mode glass for a window is provided, comprising a glass substrate having a first side and a second side, a first member disposed on the first side of the glass substrate, and a second member disposed on the second side of the glass substrate. The first and second members are configured such that the dual-mode glass exhibits a first transmittance / emissivity mode for light incident on the first side, and a second transmittance / emissivity mode for light incident on the second side.

[0006] Preferably, the first transmittance / emissivity mode is a high emissivity, low solar transmittance mode, while the second transmittance / emissivity mode is a low emissivity, high solar transmittance mode.

[0007] More preferably, the first component is a bandpass filter, and the second component is a silver coating.

[0008] In one embodiment, a silver coating is further disposed on the second side of the glass substrate, between the bandpass filter and the glass substrate.

[0009] In a variation of the preferred embodiment, ultraviolet and near-infrared rays in light illuminating the first or second side of the dual-mode glass are substantially blocked by the dual-mode glass.

[0010] In another variation of the preferred embodiment, the bandpass filter comprises a multilayer structure having alternating arrangements of high-refractive-index and low-refractive-index materials.

[0011] As can be seen, different embodiments of the present invention disclose smart windows with a dual-sided structural design, allowing users to flexibly adjust the window's function according to seasonal and climatic needs. For example, in winter, facing the low-emissivity side outwards minimizes heat radiation exchange and enhances indoor insulation; conversely, in summer, facing the bandpass filter side outwards increases window emissivity, promoting radiative cooling while maintaining visible light transmittance. This type of dual-mode window system has significant potential for improving building and vehicle energy efficiency and promoting sustainable urban development. The solution combines cost-effectiveness and environmental friendliness, further highlighting its potential for widespread application in the industry.

[0012] The above description of the invention is for illustrative purposes only and is not intended to be limiting. This disclosure includes one or more corresponding aspects, embodiments, or features, whether used alone or in various combinations, whether or not explicitly stated in such combinations or when used alone (including in the claims). It should be understood that features defined according to any aspect of this disclosure, or features associated with any specific embodiment of this disclosure, may be used alone or in combination with any other defined features, used in any other aspect or embodiment, or form further aspects or embodiments of this disclosure. Attached Figure Description

[0013] These and other aspects of this disclosure will be illustrated with reference to the accompanying drawings, which are by way of example only, wherein: Figure 1 A schematic diagram of a mechanically flip-up dual-mode smart glass for energy saving according to a first embodiment of the present invention is shown.

[0014] Figure 2This is a schematic diagram of a typical double-sided silver-plated glass.

[0015] Figure 3a It shows Figure 2 A comparison of the mid-infrared emissivity of silver-plated glass and ordinary glass.

[0016] Figure 3b Showing Figure 2 The transmittance of the silver-plated glass shown is categorized by different silver layer thicknesses.

[0017] Figure 4 This is a typical spectrum of a bandpass filter in the visible light band.

[0018] Figure 5a Presented Figure 1 The transmittance of the three-band smart window composed of dual-mode smart glass.

[0019] Figure 5b Presented Figure 1 The emissivity on both sides of the three-band smart window, which is composed of dual-mode smart glass.

[0020] Figure 6a Presented Figure 1 A schematic diagram illustrating the function of the three-band smart window, composed of dual-mode smart glass, in its winter insulation mode.

[0021] Figure 6b Presented Figure 1 A schematic diagram of the radiative cooling mode of a three-band smart window composed of dual-mode smart glass in summer heat preservation mode.

[0022] Figure 7 Showing Figure 1 A schematic diagram illustrating the application of a three-band smart window, composed of dual-mode smart glass, to residential and automotive sunroofs.

[0023] Figure 8a This demonstrates an exemplary method for regulation verification. Figure 1 Experimental device for dual-mode smart glass.

[0024] Figure 8b The temperature-time curves tested in the experiment are shown.

[0025] Figure 9a The different transmittances obtained when different substrates are combined with bandpass filters are shown.

[0026] Figure 9b The AM1.5 solar spectrum is shown. Detailed Implementation

[0027] Exemplary embodiments of the present invention relate to a dual-mode energy-saving window system, one of the features of which is an integrated structure of a reversible bandpass filter and a silver-glass-silver composite layer. The system can seamlessly switch between two modes: a low-emissivity, high-solar-transmittance mode for thermal insulation, and a high-emissivity, low-solar-transmittance mode for optimizing heat dissipation. This design focuses on optimizing the spectral performance of both sides of the window: a silver-plated layer on one side achieves extremely low infrared emissivity (low radiation), while the other side is equipped with a bandpass filter that selectively blocks harmful near-infrared and ultraviolet light while ensuring visible light transmittance.

[0028] Specifically, see Figure 1 In a first embodiment of the present invention, a mechanically flip-able dual-mode smart glass for energy saving is provided. Here, "mechanically flip-able" means that in this embodiment, the dual-mode glass can be flipped manually (including automatically by a mechanical drive device), for example, by flipping 180 degrees along its central axis (not shown), so that either side of the dual-mode glass can face one direction or be reversed to face away from that direction. Figure 1 The dual-mode glass includes a glass substrate 20 having a first side and a second side, a first silver coating 22 disposed on the first side of the glass substrate 20, a second silver coating 24 disposed on the second side of the glass substrate 20, and a bandpass filter 26 located outside the second silver coating 24 and further away from the glass substrate 20. In this embodiment, the bandpass filter 26 is also referred to as the second component, and the first silver coating 22 is also referred to as the first component. Figure 1 As can be seen, the bandpass filter 26 comprises a multilayer structure with alternating high refractive index material 30 and low refractive index material 28.

[0029] The first silver coating 22 and the bandpass filter 26 are configured such that the dual-mode glass presents a first transmittance / emissivity mode for light incident on the first side and a second transmittance / emissivity mode for light incident on the second side. Specifically, the first transmittance / emissivity mode is a high emissivity, low solar transmittance mode, while the second transmittance / emissivity mode is a low emissivity, high solar transmittance mode. The principle of this dual-mode operation will be described in detail below. Furthermore, for light illuminating either the first or second side of the dual-mode glass, ultraviolet and near-infrared rays in the light are substantially blocked by the dual-mode glass.

[0030] Next, we will describe it in detail. Figure 1 The working principle of dual-mode glass. First, let's look at the silver plating feature of the integrated structure in the above embodiment. Dual-mode glass requires silver plating on at least one side to achieve low surface emissivity. Silver-plated glass significantly suppresses window emissivity by reducing thermal conductivity and enhancing heat insulation. Figure 2The image shows a typical double-sided silvered glass, whose mid-infrared emissivity is compared to that of ordinary glass. Figure 3a As shown in the image, silvered glass offers the following advantages when used for building windows compared to ordinary glass: • Controlling mid-infrared spectral characteristics: The silver layer has excellent infrared reflection capabilities, effectively preventing indoor heat loss through windows while blocking external heat intrusion. • Enhance indoor comfort: By minimizing unnecessary heat transfer, silvered glass helps maintain a stable indoor temperature, creating a more comfortable living and working environment; • Protects indoor furniture and decorations: The silver layer also reduces ultraviolet radiation, preventing indoor furniture and decorations from fading and aging, thereby extending their service life.

[0031] Standard silver-plated glass should appear as follows Figure 3a The infrared radiation spectrum shown is illustrated (ordinary glass is also marked as a control in this figure).

[0032] The thickness of the silver layer significantly affects visible light transmittance; therefore, it is crucial to precisely control the silver layer thickness to ensure that the glass improves thermal insulation performance without compromising natural indoor lighting. The silver layer must reflect both infrared and ultraviolet rays while allowing visible light to pass through, ensuring sufficient natural indoor illumination. In embodiments of this invention, the silver layer thickness needs to be precisely controlled for dual-mode glass to achieve the optimal balance between thermal insulation performance and light transmittance. Experimental and calculation results show that the silver layer thickness significantly affects the overall transmittance of the glass. Figure 3b As shown, visible light transmittance is extremely sensitive to the thickness of the silver layer: while thickening the silver layer can enhance reflectivity, it reduces visible light transmittance, leading to insufficient indoor lighting. Therefore, the coating technology must ensure that the silver layer is uniformly deposited on the glass surface to achieve the desired optical performance and balance. This technology should ensure high visible light transmittance while improving thermal insulation performance.

[0033] Therefore, through the aforementioned silver plating design and process, the glass can achieve high thermal insulation efficiency and excellent visible light transmittance. Preferably, silver plating can be applied to both sides of the glass to obtain even better low-emissivity performance.

[0034] on the other hand, Figure 1 The dual-mode glass shown also includes a bandpass filter 26. A bandpass filter is a component designed for the selective transmission of light within a specific wavelength range. Its working principle is based on the interference effect and optical properties of materials, achieving the target spectral performance through the design of a multilayer thin-film structure. For example... Figure 1In the illustrated embodiment, the bandpass filter 26 is formed by alternating stacks of high-refractive-index material 30 and low-refractive-index material 28, with the thickness of each layer precisely controlled to create specific interference conditions. This bandpass filter 26 is fabricated on one surface of double-sided silver-plated glass. It achieves stray wavelength suppression near the visible light band and provides high emissivity in the mid-infrared band at high temperatures; while the double-sided silver-plated glass suppresses near-infrared wavelengths at low temperatures and achieves low emissivity in the mid-infrared band. When light passes through the multilayer film, light of different wavelengths undergoes partial reflection and transmission at each interface. By precisely designing the thickness and refractive index of each layer of high-refractive-index material 30 and low-refractive-index material 28, the coherent interference effect between reflected and transmitted light waves can enhance light within a specific wavelength range while attenuating or completely blocking other wavelengths. Specifically, when light passes through the multilayer film, light waves of different wavelengths are reflected and transmitted at each interface, and the superposition produces an interference effect. By designing the thickness of each layer to match the phase of reflected and transmitted light waves of a specific wavelength, an enhanced interference effect can be formed, thereby improving the transmittance of that wavelength. Non-target wavelengths, due to phase mismatch, experience reduced interference, resulting in high reflectivity or absorptivity, thus blocking these wavelengths. Therefore, the bandpass filter 26 can selectively transmit light within a specific wavelength range while blocking other wavelengths.

[0035] The design process for this type of bandpass filter should follow these steps: The first step is to select suitable high-refractive-index and low-refractive-index materials. High-refractive-index materials (such as TiO2, with a refractive index of...) ≈ 2.4) and low refractive index materials (such as SiO2, refractive index ≈ 2.4) The selection of (≈ 1.46) needs to be based on the refractive index difference, which is key to achieving the desired interference effect. Preferably, an organic optical medium is used to obtain a higher emissivity.

[0036] The second step is to determine the center wavelength of the bandpass filter based on application requirements. For example, to design a high-transmittance filter for the visible spectrum (400-700 nm), one can select... = 550 as the center wavelength.

[0037] The third step is to determine the thickness of each layer based on the center wavelength. The initial thickness is calculated using the quarter-wavelength rule: for the selected high-refractive-index layer... With low refractive index layer The formulas for calculating the thickness are as follows:

[0038] These thickness values and This forms the basis of the multi-layered structure.

[0039] The fourth step is to fine-tune the thickness and number of layers using the transfer matrix method. This involves simulating and optimizing the multi-layer structure using the transfer matrix method, and adjusting the thickness of each layer. , Composition and number of layers N This can achieve the target spectral performance.

[0040] The formula for the transfer matrix is:

[0041] in For the first i The feature matrix of the layer, M This is the transmission matrix for the entire multilayer system.

[0042] The formula for calculating the characteristic matrix is:

[0043] in and .

[0044] Following this design approach, bandpass filters with high transmittance in the visible spectrum and low transmittance in the ultraviolet and infrared regions can be achieved.

[0045] Figure 4 The spectrum of a typical bandpass filter in the visible light band is shown, revealing reasonable transmittance in the visible light range (400nm-860nm), while transmittance is close to zero in the ultraviolet and near-infrared regions (860nm-1100nm). However, this filter cannot block near-infrared light with wavelengths greater than 1100nm. This is because the design range of bandpass filters is typically limited, making it difficult to achieve an extremely wide functional passband. This phenomenon stems from limitations in material properties, interference effects, the influence of resonance peaks and sidebands, and manufacturing constraints. Therefore, in practical applications, the design of bandpass filters must strike a balance between performance requirements and manufacturability, and this phenomenon is difficult to completely avoid in the design process.

[0046] After fabricating a bandpass filter on silver-coated low-emissivity glass, a composite window with different spectral characteristics on both sides was obtained. Its spectral characteristics are as follows: Figures 5a-5b As shown: Specifically, when a bandpass filter is combined with low-emissivity glass, such as Figure 5a As shown, its visible light transmittance facing the sun decreases from approximately 65% ​​to approximately 50%, and to 35% in the silver-coated area. In the ultraviolet-near-infrared band (860nm-1100nm), the composite window is nearly opaque. The adhesion of the silver-coated low-emissivity glass significantly suppresses transmittance in the near-infrared band—a band where… Figure 4The typical bandpass filter spectrum shown was not originally suppressed. Due to the significant difference in refractive index between silver and common materials, the silver / dielectric interface has a large reflectance coefficient, resulting in high reflectivity and low transmittance. Even with a silver layer only a few nanometers thick, this effect is still very significant in the near-infrared band. Figure 5b As shown, there is a significant difference in emissivity between the two sides in the mid-infrared band. The silver layer side exhibits excellent low-emissivity characteristics, comparable to typical low-emissivity glass; while the bandpass filter side exhibits high emissivity due to the inherent high emissivity of the polymer.

[0047] according to Figure 1 The spectral characteristics of the dual-mode smart glass in this embodiment fully demonstrate its excellent temperature control potential, and its main functions for energy saving purposes include... Figures 6a-6b As shown. Figure 1 The dual-mode smart glass of the embodiment can be used to realize a flip-type three-band smart window, which can easily switch between heat preservation modes (such as...). Figure 6a (as shown) and radiative cooling mode (such as) Figure 6b As shown in the diagram, the two modes have distinctly different mid-infrared characteristics, making them particularly suitable for maintaining indoor comfort under various climatic conditions. In both modes, they block ultraviolet (UV) and near-infrared (NIR) wavelengths while ensuring transmittance in the visible (VIS) wavelength range. Figure 1 The dual-mode smart glass of the embodiment is suitable for automotive and residential applications (such as...) Figure 7 (As shown). In winter, the low-emissivity side is flipped to the outside to block heat radiation and keep the inside warm; in summer, the bandpass filter side is flipped to the outside, and the window's high thermal emissivity allows heat to dissipate outwards, keeping the inside cool. Its characteristics are explained as follows: regardless of which side faces outwards, it can effectively block ultraviolet and near-infrared rays.

[0048] 1. Ultraviolet radiation blocking: By blocking harmful ultraviolet rays, the aforementioned smart window effectively prevents interior decorations and furniture from fading and aging, thereby extending their lifespan. Ultraviolet rays are a major factor causing the deterioration and fading of many materials; therefore, the ultraviolet protection performance of this glass is crucial for maintaining the aesthetics and durability of the indoor environment.

[0049] 2. Near-infrared blocking: Blocking near-infrared radiation can significantly reduce solar heat radiation transmission, alleviating the load on air conditioning systems in summer, thereby reducing energy consumption and carbon emissions. Near-infrared radiation constitutes a significant portion of solar radiation energy; blocking this band can effectively suppress indoor heat buildup, enabling more efficient temperature control. Especially under extreme heat conditions, this feature can significantly reduce the energy consumption of air conditioning systems and improve energy efficiency.

[0050] The two functions mentioned above involve the ultraviolet and near-infrared bands. However, when flipping the window to display different sides, the visible light and mid-infrared radiation can be significantly adjusted.

[0051] 3. Winter Mode (silver-plated side facing out): Visible light transmittance: When maintaining indoor warmth in winter, rotate the silver-plated side outwards. At this time, the visible light transmittance is approximately 50%, ensuring ample natural light and creating a comfortable lighting environment. Natural light not only enhances indoor brightness and visual comfort but also helps regulate the body's circadian rhythm, improving physical and mental health and work efficiency. While maintaining high light transmittance, this product effectively suppresses glare, enhancing the comfort of living and working spaces.

[0052] Low emissivity: With an emissivity as low as 10%, it effectively locks in indoor heat and prevents heat loss through radiation. The low emissivity of the window effectively blocks heat radiation, significantly improving its insulation performance in winter.

[0053] 4. Summer mode (bandpass filter facing out): Visible light transmittance: When keeping the room cool in summer, rotate the bandpass filter so that the side facing outwards. At this point, the visible light transmittance is approximately 35%. Further reducing visible light transmittance can effectively reduce solar radiation entering the room under strong summer sunlight, significantly suppressing the rise in indoor temperature. Furthermore, reducing light transmittance in the midsummer heat can alleviate indoor glare and create a more comfortable visual environment. This is especially important for people who work or live in areas with direct sunlight, helping to reduce eye strain and improve their quality of life.

[0054] High emissivity: Emissivity is approximately 85%. When the exterior surface of the window is heated by sunlight and the ambient temperature is higher than the indoor temperature, it is necessary to effectively reduce the temperature of the exterior surface to prevent heat radiation into the room. The high emissivity of the exterior surface allows for efficient heat dissipation to the environment, thereby reducing the air conditioning load and saving energy.

[0055] To verify the effective regulating capability of this invention under hot and cold environments, a sunlight exposure experiment was designed. For example... Figure 8a As shown, the smart window sample is placed in an acrylic sample holder, which is wrapped with aluminum foil to prevent it from absorbing sunlight and heating up, ensuring experimental accuracy. The bottom of the sample holder is a sealed chamber, simulating a closed environment such as a building or vehicle. A layer of carbon black is laid at the bottom of the chamber to simulate the temperature changes of objects inside the room / vehicle under sunlight.

[0056] like Figure 8bAs shown, the sample with the silver coating facing the sky consistently had a higher temperature than the sample with the bandpass filter facing the sky. This is primarily because when the silver coating faces the sky, more visible light penetrates the glass, making the objects inside the cavity more susceptible to heating. Simultaneously, the low emissivity of the silver layer hinders heat radiation from the cavity, thus retaining heat within the cavity. Conversely, when the bandpass filter faces the sky, the transmittance of the glass in the visible spectrum decreases, reducing the heating effect of sunlight on the objects inside. Furthermore, its inherently high emissivity effectively dissipates heat to the surrounding environment, thus effectively controlling the indoor temperature.

[0057] Figure 9a The results show that, compared to conventional ITO (indium tin oxide) coated glass and ordinary glass (uncoated), double-sided silver-plated glass exhibits acceptable transmittance in the visible light band and demonstrates the best suppression effect in the near-infrared band, maximizing the blocking of solar radiation in this band (such as...). Figure 9b As shown, and please refer to [1] Standard, ASTM "G173-03 - standard tables for reference solar spectral irradiances: Direct normal and hemispherical on 37° tilted surface." Ann. Book of ASTM Standards 2003 14 (2012): 1-20.).

[0058] Experimental results show that the flip-up smart window provided by the exemplary embodiment of the present invention has strong adjustment capabilities under both high and low temperature conditions, demonstrating broad application prospects.

[0059] The exemplary embodiment of this invention provides a flip-up smart window with a double-sided design, which can optimize light and heat performance under different seasons and environmental conditions. Regardless of which side faces outward, it can effectively block ultraviolet (UV) and near-infrared (NIR) rays, preventing fading and aging of interior decorations and furniture, and significantly reducing indoor solar heat conduction. Its adjustment range is wider than that of existing technologies.

[0060] Compared to existing smart window technologies, the flip-up smart window provided in the exemplary embodiments of the present invention has significant advantages.

[0061] 1. Seasonal Optimization Mode: Winter Mode: When indoor heating is required, the bandpass filter faces outwards, maintaining 50% visible light transmittance and 10% ultra-low emissivity. This ensures ample natural light while effectively preventing heat loss through radiation, improving indoor comfort and energy efficiency.

[0062] Summer Mode: When indoor cooling is required, the silver side faces outwards, reducing visible light transmittance to 35% and increasing emissivity to 85%. This configuration effectively reduces solar heat entering the room, lowers the air conditioning load, improves energy efficiency, and minimizes indoor glare, enhancing visual comfort.

[0063] 2. Static optical performance: Unlike electrochromic or thermochromic windows, the flip-up smart window provided in the exemplary embodiments of the present invention relies on the inherent optical properties of the material and does not require external current or temperature changes to drive it, thus completely avoiding the problems of response delay and durability.

[0064] 3. Energy-saving characteristics: Ultraviolet and near-infrared blocking: Effectively blocks ultraviolet and near-infrared rays, delays material aging, reduces indoor heat gain, and lowers energy consumption and carbon emissions.

[0065] Optical control: The double-sided design enables precise control of light and heat, significantly improving energy efficiency.

[0066] 4. Safe and environmentally friendly: It contains no toxic substances or liquids that pose a risk of leakage, ensuring user safety and environmental compliance, and eliminating health and environmental hazards caused by material leakage.

[0067] 5. Cost-effectiveness: Its simple structure eliminates the need for complex processes, effectively reducing production costs.

[0068] 6. Visual comfort and health: Glare suppression: Summer mode reduces visible light transmittance, effectively reducing glare, improving visual comfort, and alleviating eye fatigue.

[0069] Natural lighting utilization: 50% visible light transmittance in winter mode ensures ample natural light, which helps regulate the body's circadian rhythm and promotes physical and mental health and work efficiency.

[0070] The exemplary embodiment of this invention provides a flip-up smart window that achieves seasonal light and heat optimization through a double-sided design, offering higher reliability, maintenance-free operation, and significant energy savings compared to existing smart window technologies. Its precise control of light and heat characteristics enhances visual comfort and durability, while its environmentally friendly and safe features further strengthen its competitiveness in the smart window market.

[0071] The embodiments described above have been thoroughly explained. Although the specification refers to specific embodiments, those skilled in the art will understand that the invention can be modified in detail without changing the core principles. Therefore, the invention should not be considered as limited to the embodiments described herein.

[0072] While embodiments have been described in detail with reference to the accompanying drawings and the foregoing description, such descriptions are exemplary and not restrictive. It should be understood that this document illustrates exemplary embodiments only and does not limit the scope of the invention in any way. It is understood that any feature described herein can be used in conjunction with any embodiment. There is no exclusivity between exemplary embodiments, nor are other embodiments not mentioned herein excluded. Therefore, the present invention also provides embodiments that include one or more combinations of the illustrative embodiments described above. Modifications and variations to the content of this invention do not depart from its spirit and scope.

Claims

1. A dual-mode glass for a window, comprising: A glass substrate having a first side and a second side; A first component disposed on a first side of the glass substrate; as well as A second component disposed on the second side of the glass substrate; The first and second components are configured such that the dual-mode glass presents a first transmittance / emissivity mode for light incident on the first side and a second transmittance / emissivity mode for light incident on the second side.

2. The dual-mode glass as claimed in claim 1, wherein the first transmittance / emissivity mode is a high emissivity, low solar transmittance mode, and the second transmittance / emissivity mode is a low emissivity, high solar transmittance mode.

3. The dual-mode glass of claim 2, wherein the first component is a bandpass filter and the second component is a silver coating.

4. The dual-mode glass of claim 3, wherein a silver coating is further disposed on the second side of the glass substrate, between the bandpass filter and the glass substrate.

5. The dual-mode glass of claim 1, wherein ultraviolet and near-infrared rays in light irradiating the first or second side of the dual-mode glass are substantially blocked by the dual-mode glass.

6. The dual-mode glass of claim 2, wherein the bandpass filter comprises a multilayer structure having alternating high-refractive-index and low-refractive-index materials.

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